Systematic bilateral internal mammary artery grafting: lessons learned from the CATHolic University EXtensive BIMA Grafting Study

Systematic bilateral internal mammary artery grafting: lessons learned from the CATHolic... Abstract OBJECTIVES Despite claims of feasibility, to date no study has examined the effect of systematic bilateral internal mammary artery (BIMA) use in a large cohort of real-world unselected patients. The CATHolic University EXtensive BIMA Grafting Study (CATHEXIS) registry was designed to assess the feasibility and safety of systematic BIMA grafting. METHODS The CATHEXIS was a single-centre, prospective, observational, propensity-matched study. The study was supposed to include 2 arms of 500 patients each: a prospective arm and a retrospective arm. The prospective arm included almost all patients referred for coronary artery bypass grafting (CABG) at our institution after the start of the CATHEXIS with very few exceptions. BIMA would have been used in all these patients. The retrospective arm included patients submitted to CABG before the start of the CATHEXIS and propensity matched to the prospective group (average BIMA use 50%; the radial artery was extensively used). Safety analyses were scheduled after enrolment of 200, 300 and 400 BIMA patients. RESULTS After the first 226 patients, the BIMA use percentage was 88.5% (200 of 226). In 178 (89%) patients, mammary arteries were used as Y graft. Postoperative mortality was 2%, and incidence of perioperative myocardial infarction, graft failure and sternal complications were 3.5%, 3% and 5.5%, respectively. No perioperative stroke occurred. The incidence of major adverse cardiac events (particularly graft failure and sternal complications) in the BIMA arm were significantly higher than those in the propensity-matched cohort; the study was stopped for safety. CONCLUSIONS In a real world setting the systematic use of BIMA was associated with a higher incidence of perioperative adverse events (particularly sternal complications). Individualization of the revascularization strategy and use of alternative arterial conduits are probably preferable to systematic use of BIMA. Coronary artery bypass grafting , Bilateral internal mammary artery , Coronary artery disease INTRODUCTION Despite several guidelines and position papers recommending a wider use of bilateral internal mammary arteries (BIMAs) [1–3], no study has been published on the feasibility of systematic BIMA use. In all the published studies, the use of BIMA has been restricted to a portion of the overall population, and the BIMA group has in some way been selected by the operating surgeons. In October 2012, we started a complete re-engineering of our institutional strategy for coronary artery bypass grafting (CABG) surgery towards a systematic adoption of BIMA grafting. At that time, the evidence of the clinical benefits associated with BIMA use was even more solid than today. The literature was almost unanimously concordant in reporting that BIMA use did not increase operative mortality and morbidity, even in subgroups of high-risk patients [4–6]. A very large body of observational evidence summarized in 2 independent meta-analyses showed significant long-term survival benefit using BIMA for CABG, without adverse effect in terms of mortality [7, 8]. According to the 2010 Guidelines of the Task Force on Myocardial Revascularization of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS), complete revascularization with arterial grafts was a Class IA recommendation for patients with reasonable life expectancy [9]. Our centre had a very solid tradition with the use of arterial grafts for CABG, and at that time, approximately 70–80% of our patients referred for non-emergent CABG received more than 1 arterial graft. BIMA was used in almost half of the cases, and the radial artery was extensively used. Despite our good results, the evidence supporting the use of BIMA was clearly superior to that supporting the radial artery. On this basis, we decided to progressively adopt systematic BIMA grafting in every patient referred to our institution who met the criteria depicted in guidelines. The CATHolic University EXtensive BIMA Grafting Study (CATHEXIS) registry was designed to record this transition and to assess the feasibility and safety of systematic use of BIMA for treatment of multivessel coronary artery disease in an unrestricted consecutive cohort of patients undergoing CABG at a large academic cardiac surgery department. After an initial phase of progressive increase in the rate of BIMA use, the CATHEXIS was started on 16 April 2012. We herein report our results. MATERIALS AND METHODS Study design The CATHEXIS was an observational, non-randomized single-centre study started on 16 April 2012 at the Department of Cardiovascular Medicine of the Catholic University of Rome (ClinicalTrials.gov, identifier NTC01593865). The trial was aimed at prospectively including 500 patients undergoing primary non-emergent isolated multivessel CABG with BIMA and to compare them with a retrospective cohort of 500 historic propensity-matched controls. Exclusion criteria were emergency status, previous cardiac operation, associated cardiac procedures other than CABG, preoperative left ventricular ejection fraction <30% and expected life expectancy <5 years. End points The primary end point of the CATHEXIS was to assess whether systematic BIMA grafting was feasible as a routine intervention in the clinical practice of a large academic cardiac surgery centre. Systematic BIMA grafting would have been considered feasible if the trial inclusion rate (number of BIMA patients versus total number of eligible patients) would have been ≥80% during the study period. As there was already solid evidence on the safety of BIMA and based on the available literature, our study was underpowered to detect differences in clinical outcomes, we considered safety a secondary end point. The secondary end point of the CATHEXIS was to evaluate differences in the rate of major adverse cardiac events (death, acute myocardial infarction, graft failure) and in the rate of sternotomy-related complications between the CATHEXIS patients and a control retrospective CABG group. A first interim efficacy analysis was planned after enrolment of the first 100 BIMA patients, and safety analyses were scheduled after enrolment of 200, 300 and 400 BIMA patients. Because of the observational nature of the study and the fact that the intervention was a Class IA recommendation according to the contemporary guidelines, no specific consent to participate in the CATHEXIS was requested. All patients consented to the surgical procedure and data collection. Patient groups The prospective arm (BIMA Group) was supposed to enrol 500 consecutive patients undergoing CABG with BIMA. The eligibility and the best revascularization strategy in each patient were assessed by the local Heart Team on the basis of clinical and anatomical conditions. The retrospective group (pre-CATHEXIS group) was designed to consist of 500 consecutive, historical control patients who received standard CABG from March 2012 going backwards. For this analysis, the control group consisted of patients operated on between January 2009 and March 2012. The percentage of BIMA use in this group was approximately 50% (Supplementary Material, Fig. S1). Data collection The data of patients in the BIMA study group were prospectively recorded in a datasheet divided into a preoperative section, an intraoperative section and a postoperative section. The preoperative data included age, gender, weight, height, body mass index (BMI), the presence of renal failure (defined as serum creatinine level >2.0 mg/dl), diabetes (defined as glucose blood levels >126 mg/dl or antidiabetic therapy) or chronic obstructive pulmonary disease, left ventricular ejection fraction (measured by Simpson rule using 2-dimensional echocardiography) and the logistic EuroSCORE. Obesity was defined as BMI >30 kg/m2. The intraoperative data included total operative time (from skin incision to skin closure), cardiopulmonary bypass time, cross-clamping time, type of conduits used, their configuration and coronary targets; for each bypass mean flow, pulsatility index and backward flow, measured by intraoperative transit-time flowmetry, were recorded. The postoperative data included bleeding in the first 24 h, the need for blood transfusion, type and number of postoperative complications and duration of the intensive care unit stay and in-hospital stay. Postoperative myocardial infarction was defined according to the universal definition in use at that time [10]. The same data were collected for patients included in the retrospective control group of patients from the electronic database of our hospital. Data of the control group were also prospectively collected. Per institutional protocols, we are very aggressive in performing control reangiography in the postoperative period [11]. Clinical, laboratory, ECG or echocardiographic evidence of ischaemia, as well as arrhythmias, prolonged low cardiac output, and marginal results at intraoperative flowmetric evaluation were indication for reangiography. Surgical technique All cases were operated using full median sternotomy, normothermic cardiopulmonary bypass, single aortic clamping and isothermic, intermittent, antegrade blood cardioplegia. Internal mammary arteries were harvested skeletonized and used to graft the main target vessels. Additional radial artery or saphenous vein grafts were used to complete revascularization. The 2 mammary arteries were used either in situ or as a Y graft depending on the anatomy of the coronary arteries and the surgeon’s intraoperative choice. The use of sequentials, double Y grafts and alternative inflow sources were also allowed. Intraoperative flowmetric evaluation was used in all cases. Statistical analysis Demographic and clinical data are presented as frequency distributions and simple percentages. Values of continuous variables are expressed as mean ± standard deviation. For propensity matching, a propensity score was generated for each patient from a multivariable logistic regression model based on the following preoperative covariates: age, gender, diabetes, chronic pulmonary disease, renal insufficiency, obesity, preoperative ejection fraction and EuroSCORE, with treatment type (control versus the CATHEXIS) as a binary dependent variable. The resulting propensity score represented the probability that a patient underwent BIMA grafting. BIMA patients were then matched to the standard CABG patients in a 1:1 ratio using a Rosenbaum optimal matching algorithm and a caliper size of 0.05. This approach minimized the overall distance between observations and was conducted using the Mahalanobis distance within propensity score calipers (no matches outside the calipers). The quality of the match was assessed using standardized difference. To assess differences in matched cohorts, the McNemar test was used to test categorical variables and paired t-test for continuous variables. All analyses were performed using the Number Cruncher Statistical Systems software (Version 8, Copyright 2012, NCSS, Kaysville, UT, USA) and Stata (Version 12, Copyright 2012, StataCorp LP, College Station, TX, USA). RESULTS From 16 April 2012 to 14 March 2013, 226 patients matching the inclusion criteria were referred to our centre. Of these, 11 (4.9%) patients were excluded preoperatively due to anatomical considerations on the status and quality of the target vessels. Another 15 (6.6%) patients were excluded intraoperatively for technical problems or considerations related to the quality of the conduits or the target vessels. Two hundred patients of the 226 (88.5%) patients received BIMA. Demographic characteristics The demographic and clinical characteristics of the 200 BIMA patients are listed in Table 1. The mean age was 66 ± 9 years, and the great majority of patients were men. The mean preoperative ejection fraction was 56 ± 8%, and the mean preoperative EuroSCORE was 3.7 ± 3.9. Table 1: Preoperative data of the 200 CATHEXIS patients Mean age, mean ± SD (range)  66 ± 9 (42–82)  Male, n (%)  183 (91.5)  Diabetes, n (%)  71 (35.5)  Chronic pulmonary disease, n (%)  13 (6.5)  Peripheral vascular disease, n (%)  11 (5.5)  Hypertension, n (%)  87 (43.5)  Dyslipidaemia, n (%)  91 (45.5)  Obesity, n (%)  38 (19)  Renal insufficiency, n (%)  6 (3)  Coronary disease, n (%)     Left main  19 (9.5)   3-vessel disease  148 (74)   2-vessel disease  33 (16.5)  Preoperative LVEF, mean ± SD (range)  56.1 ± 7.7 (34–71)  Mean EuroSCORE, mean ± SD  3.7 ± 3.9  Mean age, mean ± SD (range)  66 ± 9 (42–82)  Male, n (%)  183 (91.5)  Diabetes, n (%)  71 (35.5)  Chronic pulmonary disease, n (%)  13 (6.5)  Peripheral vascular disease, n (%)  11 (5.5)  Hypertension, n (%)  87 (43.5)  Dyslipidaemia, n (%)  91 (45.5)  Obesity, n (%)  38 (19)  Renal insufficiency, n (%)  6 (3)  Coronary disease, n (%)     Left main  19 (9.5)   3-vessel disease  148 (74)   2-vessel disease  33 (16.5)  Preoperative LVEF, mean ± SD (range)  56.1 ± 7.7 (34–71)  Mean EuroSCORE, mean ± SD  3.7 ± 3.9  LVEF: left ventricular ejection fraction; SD: standard deviation. Table 1: Preoperative data of the 200 CATHEXIS patients Mean age, mean ± SD (range)  66 ± 9 (42–82)  Male, n (%)  183 (91.5)  Diabetes, n (%)  71 (35.5)  Chronic pulmonary disease, n (%)  13 (6.5)  Peripheral vascular disease, n (%)  11 (5.5)  Hypertension, n (%)  87 (43.5)  Dyslipidaemia, n (%)  91 (45.5)  Obesity, n (%)  38 (19)  Renal insufficiency, n (%)  6 (3)  Coronary disease, n (%)     Left main  19 (9.5)   3-vessel disease  148 (74)   2-vessel disease  33 (16.5)  Preoperative LVEF, mean ± SD (range)  56.1 ± 7.7 (34–71)  Mean EuroSCORE, mean ± SD  3.7 ± 3.9  Mean age, mean ± SD (range)  66 ± 9 (42–82)  Male, n (%)  183 (91.5)  Diabetes, n (%)  71 (35.5)  Chronic pulmonary disease, n (%)  13 (6.5)  Peripheral vascular disease, n (%)  11 (5.5)  Hypertension, n (%)  87 (43.5)  Dyslipidaemia, n (%)  91 (45.5)  Obesity, n (%)  38 (19)  Renal insufficiency, n (%)  6 (3)  Coronary disease, n (%)     Left main  19 (9.5)   3-vessel disease  148 (74)   2-vessel disease  33 (16.5)  Preoperative LVEF, mean ± SD (range)  56.1 ± 7.7 (34–71)  Mean EuroSCORE, mean ± SD  3.7 ± 3.9  LVEF: left ventricular ejection fraction; SD: standard deviation. Perioperative data The mean number of grafts, arterial grafts and grafts with mammary artery per patient was 2.60 ± 0.70, 2.40 ± 0.72 and 2.38 ± 0.65, respectively. In 178 (89%) patients, the mammary arteries were used in Y graft configuration. Total arterial revascularization was obtained in 138 (69%) cases. Table 2 shows the targets of the internal mammary arteries and Table 3 the results of the intraoperative flow evaluation. Table 2: Targets of the mammary arteries in the CATHEXIS patients   n (%)  LIMA     LAD  158 (79)   D-LAD  25 (12.5)   OM  17 (8.5)  RIMA     OM  134 (67)   OM-PDA  20 (10)   OM-PL  8 (4)   OM2-OM1  4 (2)   PL  2 (1)   LAD  10 (5)   D  10 (5)   D-LAD  4 (2)   AL  7 (3.5)   AL-PL-PDA  1 (0.5)    n (%)  LIMA     LAD  158 (79)   D-LAD  25 (12.5)   OM  17 (8.5)  RIMA     OM  134 (67)   OM-PDA  20 (10)   OM-PL  8 (4)   OM2-OM1  4 (2)   PL  2 (1)   LAD  10 (5)   D  10 (5)   D-LAD  4 (2)   AL  7 (3.5)   AL-PL-PDA  1 (0.5)  AL: anterolateral branch; D: diagonal branch; LAD: left anterior descending artery; LIMA: left internal mammary artery; OM: obtuse marginal artery; PDA: posterior interventricular artery; PL: posterolateral branch; RCA: right coronary artery; RIMA: right internal mammary artery. Table 2: Targets of the mammary arteries in the CATHEXIS patients   n (%)  LIMA     LAD  158 (79)   D-LAD  25 (12.5)   OM  17 (8.5)  RIMA     OM  134 (67)   OM-PDA  20 (10)   OM-PL  8 (4)   OM2-OM1  4 (2)   PL  2 (1)   LAD  10 (5)   D  10 (5)   D-LAD  4 (2)   AL  7 (3.5)   AL-PL-PDA  1 (0.5)    n (%)  LIMA     LAD  158 (79)   D-LAD  25 (12.5)   OM  17 (8.5)  RIMA     OM  134 (67)   OM-PDA  20 (10)   OM-PL  8 (4)   OM2-OM1  4 (2)   PL  2 (1)   LAD  10 (5)   D  10 (5)   D-LAD  4 (2)   AL  7 (3.5)   AL-PL-PDA  1 (0.5)  AL: anterolateral branch; D: diagonal branch; LAD: left anterior descending artery; LIMA: left internal mammary artery; OM: obtuse marginal artery; PDA: posterior interventricular artery; PL: posterolateral branch; RCA: right coronary artery; RIMA: right internal mammary artery. Table 3: Results of intraoperative flow evaluation in the CATHEXIS patients   Flow (ml/min)  Pulsatility index  Y graft main  57.09 (41.52–75.29)  1.97 (1.34–2.69)  LIMA  45.79 (29.73–61.71)  2.11 (1.33–3.01)  RIMA  32.51 (20.31–46.16)  2.71 (1.20–4.25)    Flow (ml/min)  Pulsatility index  Y graft main  57.09 (41.52–75.29)  1.97 (1.34–2.69)  LIMA  45.79 (29.73–61.71)  2.11 (1.33–3.01)  RIMA  32.51 (20.31–46.16)  2.71 (1.20–4.25)  Values are presented as median (lower quartile interval–upper quartile interval). LIMA: left internal mammary artery; RIMA: right internal mammary artery. Table 3: Results of intraoperative flow evaluation in the CATHEXIS patients   Flow (ml/min)  Pulsatility index  Y graft main  57.09 (41.52–75.29)  1.97 (1.34–2.69)  LIMA  45.79 (29.73–61.71)  2.11 (1.33–3.01)  RIMA  32.51 (20.31–46.16)  2.71 (1.20–4.25)    Flow (ml/min)  Pulsatility index  Y graft main  57.09 (41.52–75.29)  1.97 (1.34–2.69)  LIMA  45.79 (29.73–61.71)  2.11 (1.33–3.01)  RIMA  32.51 (20.31–46.16)  2.71 (1.20–4.25)  Values are presented as median (lower quartile interval–upper quartile interval). LIMA: left internal mammary artery; RIMA: right internal mammary artery. The mean ± standard deviation operating time, clamping time and cardiopulmonary bypass time were 277 ± 44, 53 ± 16, 64 ± 17 min, respectively. Postoperative data The main postoperative complications are shown in Table 4. Four patients died: 2 due to multiorgan failure, 1 due to arrhythmia and 1 due to perioperative myocardial infarction. Table 4: Postoperative course of the 200 CATHEXIS patients Death, n (%)  4 (2)  Atrial fibrillation, n (%)  45 (22.5)  Myocardial infarction, n (%)  7 (3.5)  Reintervention for bleeding, n (%)  7 (3.5)  Prolonged ventilatory support, n (%)  6 (3)  Delirium, n (%)  1 (0.5)  Graft failure, n (%)  6 (3)  Sternal complications, n (%)  11 (5.5)  Death, n (%)  4 (2)  Atrial fibrillation, n (%)  45 (22.5)  Myocardial infarction, n (%)  7 (3.5)  Reintervention for bleeding, n (%)  7 (3.5)  Prolonged ventilatory support, n (%)  6 (3)  Delirium, n (%)  1 (0.5)  Graft failure, n (%)  6 (3)  Sternal complications, n (%)  11 (5.5)  Table 4: Postoperative course of the 200 CATHEXIS patients Death, n (%)  4 (2)  Atrial fibrillation, n (%)  45 (22.5)  Myocardial infarction, n (%)  7 (3.5)  Reintervention for bleeding, n (%)  7 (3.5)  Prolonged ventilatory support, n (%)  6 (3)  Delirium, n (%)  1 (0.5)  Graft failure, n (%)  6 (3)  Sternal complications, n (%)  11 (5.5)  Death, n (%)  4 (2)  Atrial fibrillation, n (%)  45 (22.5)  Myocardial infarction, n (%)  7 (3.5)  Reintervention for bleeding, n (%)  7 (3.5)  Prolonged ventilatory support, n (%)  6 (3)  Delirium, n (%)  1 (0.5)  Graft failure, n (%)  6 (3)  Sternal complications, n (%)  11 (5.5)  There were 7 (3.5%) perioperative myocardial infarctions. No postoperative stroke occurred. Other complications were atrial fibrillation (22.5%) and reoperation for bleeding (3.5%). Nine patients were submitted to control reangiography before discharge. Six of them (3% of the overall BIMA cohort) underwent percutaneous intervention due to graft failure. The culprit graft was always the left or right branch of the Y graft. In the remaining 3 cases, the angiographic findings were occlusion of an ungrafted coronary artery, diffuse coronary artery spasm and normal findings (1 case each). Mean stay in the intensive care unit and hospital after surgery was 2.55 ± 1.86 and 7.32 ± 4.00 days, respectively. Sternal wound complications occurred in 11 (5.5%) patients. Ten of them were diabetics (6 insulin dependent and 4 non-insulin dependent), so that the incidence of sternal complications in diabetics was 14% (10 of 71). Eight sternal complications (4%) were deep (involving the sternum), whereas the remaining 3 were superficial (limited to skin and subcutaneous tissue). Mean hospital stay for patient with sternal complications was 30 ± 14 days. Data of the unmatched control population are given in the Supplementary Material, Table S1. Propensity matching led to 2 groups of 150 pairs with minimal residual imbalance (Table 5). The Y graft was used in 137 (91.3%) patients in the CATHEXIS group and in 38 (25.3%) in the control group (P < 0.001). When compared with patients operated in the pre-CATHEXIS era, BIMA patients had higher (although not significantly) rates of death and myocardial infarction and a significantly higher incidence of graft failure, sternal complications and major cardiac events (Table 6). In the control group, no patients had to be submitted to control reangiography. Table 5: Preoperative data of the 150 matched pairs   CATHEXIS patients  Control patients  Standardized difference  Mean age, mean ± SD  65.1 ± 7.3  64.5 ± 8.2  0.03  Male, n (%)  135 (90)  133 (88.6)  0.02  Diabetes, n (%)  64 (42.6)  65 (43.3)  0.01  Chronic pulmonary disease, n (%)  7 (4.6)  5 (3.3)  0.03  Peripheral vascular disease, n (%)  9 (6.0)  8 (5.3)  0.02  Hypertension, n (%)  69 (46)  70 (46.6)  0.02  Dyslipidaemia, n (%)  72 (48)  71 (47.3)  0.02  Obesity, n (%)  26 (17.3)  22 (14.6)  0.03  Renal insufficiency, n (%)  5 (3.3)  7 (4.6)  0.03  Preoperative LVEF, mean ± SD  55.2 ± 5.8  54.1 ± 5.5  0.07  Mean EuroSCORE, mean ± SD  3.9 ± 3.1  3.8 ± 2.9  0.02    CATHEXIS patients  Control patients  Standardized difference  Mean age, mean ± SD  65.1 ± 7.3  64.5 ± 8.2  0.03  Male, n (%)  135 (90)  133 (88.6)  0.02  Diabetes, n (%)  64 (42.6)  65 (43.3)  0.01  Chronic pulmonary disease, n (%)  7 (4.6)  5 (3.3)  0.03  Peripheral vascular disease, n (%)  9 (6.0)  8 (5.3)  0.02  Hypertension, n (%)  69 (46)  70 (46.6)  0.02  Dyslipidaemia, n (%)  72 (48)  71 (47.3)  0.02  Obesity, n (%)  26 (17.3)  22 (14.6)  0.03  Renal insufficiency, n (%)  5 (3.3)  7 (4.6)  0.03  Preoperative LVEF, mean ± SD  55.2 ± 5.8  54.1 ± 5.5  0.07  Mean EuroSCORE, mean ± SD  3.9 ± 3.1  3.8 ± 2.9  0.02  LVEF: left ventricular ejection fraction; SD: standard deviation. Table 5: Preoperative data of the 150 matched pairs   CATHEXIS patients  Control patients  Standardized difference  Mean age, mean ± SD  65.1 ± 7.3  64.5 ± 8.2  0.03  Male, n (%)  135 (90)  133 (88.6)  0.02  Diabetes, n (%)  64 (42.6)  65 (43.3)  0.01  Chronic pulmonary disease, n (%)  7 (4.6)  5 (3.3)  0.03  Peripheral vascular disease, n (%)  9 (6.0)  8 (5.3)  0.02  Hypertension, n (%)  69 (46)  70 (46.6)  0.02  Dyslipidaemia, n (%)  72 (48)  71 (47.3)  0.02  Obesity, n (%)  26 (17.3)  22 (14.6)  0.03  Renal insufficiency, n (%)  5 (3.3)  7 (4.6)  0.03  Preoperative LVEF, mean ± SD  55.2 ± 5.8  54.1 ± 5.5  0.07  Mean EuroSCORE, mean ± SD  3.9 ± 3.1  3.8 ± 2.9  0.02    CATHEXIS patients  Control patients  Standardized difference  Mean age, mean ± SD  65.1 ± 7.3  64.5 ± 8.2  0.03  Male, n (%)  135 (90)  133 (88.6)  0.02  Diabetes, n (%)  64 (42.6)  65 (43.3)  0.01  Chronic pulmonary disease, n (%)  7 (4.6)  5 (3.3)  0.03  Peripheral vascular disease, n (%)  9 (6.0)  8 (5.3)  0.02  Hypertension, n (%)  69 (46)  70 (46.6)  0.02  Dyslipidaemia, n (%)  72 (48)  71 (47.3)  0.02  Obesity, n (%)  26 (17.3)  22 (14.6)  0.03  Renal insufficiency, n (%)  5 (3.3)  7 (4.6)  0.03  Preoperative LVEF, mean ± SD  55.2 ± 5.8  54.1 ± 5.5  0.07  Mean EuroSCORE, mean ± SD  3.9 ± 3.1  3.8 ± 2.9  0.02  LVEF: left ventricular ejection fraction; SD: standard deviation. Table 6: Postoperative course of the 150 matched pairs   CATHEXIS patients, n (%)  Control patients, n (%)  P-value  BIMA use  150 (100)  66 (44)  0.001  Use of 2 arterial grafts  150 (100)  122 (81.3)  <0.001  Death  3 (2)  1 (0.6)  0.31  Myocardial infarction  4 (2.6)  1 (0.6)  0.17  Graft failure  4 (2.6)  0  0.044  Sternal complications  9 (6)  2 (1.3)  0.031  Stroke  0  1 (0.6)  0.31  MACE  11 (7.3)  2 (1.3)  0.010    CATHEXIS patients, n (%)  Control patients, n (%)  P-value  BIMA use  150 (100)  66 (44)  0.001  Use of 2 arterial grafts  150 (100)  122 (81.3)  <0.001  Death  3 (2)  1 (0.6)  0.31  Myocardial infarction  4 (2.6)  1 (0.6)  0.17  Graft failure  4 (2.6)  0  0.044  Sternal complications  9 (6)  2 (1.3)  0.031  Stroke  0  1 (0.6)  0.31  MACE  11 (7.3)  2 (1.3)  0.010  BIMA: bilateral internal mammary artery; MACE: major adverse cardiac events (death, myocardial infarction, graft failure). Table 6: Postoperative course of the 150 matched pairs   CATHEXIS patients, n (%)  Control patients, n (%)  P-value  BIMA use  150 (100)  66 (44)  0.001  Use of 2 arterial grafts  150 (100)  122 (81.3)  <0.001  Death  3 (2)  1 (0.6)  0.31  Myocardial infarction  4 (2.6)  1 (0.6)  0.17  Graft failure  4 (2.6)  0  0.044  Sternal complications  9 (6)  2 (1.3)  0.031  Stroke  0  1 (0.6)  0.31  MACE  11 (7.3)  2 (1.3)  0.010    CATHEXIS patients, n (%)  Control patients, n (%)  P-value  BIMA use  150 (100)  66 (44)  0.001  Use of 2 arterial grafts  150 (100)  122 (81.3)  <0.001  Death  3 (2)  1 (0.6)  0.31  Myocardial infarction  4 (2.6)  1 (0.6)  0.17  Graft failure  4 (2.6)  0  0.044  Sternal complications  9 (6)  2 (1.3)  0.031  Stroke  0  1 (0.6)  0.31  MACE  11 (7.3)  2 (1.3)  0.010  BIMA: bilateral internal mammary artery; MACE: major adverse cardiac events (death, myocardial infarction, graft failure). On the basis of aforementioned data, the CATHEXIS was stopped for safety reasons on 14 March 2013. We went back to our pre-CATHEXIS grafting strategy. DISCUSSION We have a long-standing tradition in coronary surgery. In the early 90s, we pioneered the use of arterial grafts [12–14]. All the surgeons involved in the CATHEXIS had more than 10 years of experience with the use of BIMA. For some of them, the years of experience with BIMA were 15 or 20. The majority of us were using a second arterial graft in 70–80% of their CABG cases before starting the CATHEXIS, although often the second arterial graft was the radial artery. The available evidence at the time of the CATHEXIS was clearly supporting the safety and effectiveness of BIMA in improving postoperative outcomes [4–8], and according to the guidelines, complete revascularization with arterial grafts was a Class IA recommendation for patients with reasonable life expectancy [1, 2]. The evidence in support of the use of BIMA appeared more solid that the one in favour of the use of the radial artery and the routine use of BIMA had often been advocated. On this basis, we were confident that re-engineering our CABG strategy towards the systematic use of BIMA was a step in the right direction. After the CATHEXIS, we went back to a strategy for frequent use of the radial artery and careful individualization of the choice of the arterial conduits in accordance with the characteristics of a single patient. Our results went back to the pretrial era very quickly, and we were able to maintain the percentage of the use of a second arterial graft at approximately 80% of our CABG population. Although bad experiences with systematic BIMA use are often the subject of conversation in the hallways of national and international meetings, they are very rarely brought to the podium. To date, no study on systematic use of BIMA has been published. Indeed, in almost all of the existing studies, the operation has been reserved to a selected portion of the total of CABG cases. In a recent publication using the SWEDEHEART registry, the percentage of BIMA use in a nationwide real-world setting was 1% [15]. The process of preoperatively selecting the patients on the basis of their clinical and angiographic characteristics and the surgeon’s technical skill is probably the key in determining the safety and long-term results of BIMA. When this process is abandoned and BIMA becomes a per-protocol choice, safety can be jeopardized. The Arterial Revascularization Trial (ART) is the only large-scale study where the decision to use BIMA was based on the randomization process and not on the decision of the operating surgeon [16]. However, even in ART, only 28% of the patients who met the eligibility criteria were actually randomized, so that a process of preselection was clearly part of the study. Also, in ART, 16.4% of patients randomized to BIMA received a single mammary at surgery. This high percentage of crossover expresses the technical difficulty of systematically using BIMA. This is even more notable because in ART, the participating surgeons were selected based on their experience with BIMA grafting and were considered experts of the technique. In the CATHEXIS, 88.4% of the eligible patients received BIMA, and the crossover from BIMA to single mammary was 6.9%. There is no doubt that the use of BIMA substantially increases the technical complexity of the operation. In the majority of the cases, skilled surgeons with adequate experience can overcome the technical difficulties. In most situations, there are technical solutions to overcome length, calibre and geometric issues (although at the price of exponentially increasing complexity). The use of skeletonization, multiple sequentials, Y or double Y grafts and alternative inflow sources are part of this armamentarium and allow the use of BIMA in a selected majority of CABG cases. As a group, we were all familiar with these techniques. However, when we started using BIMA in a systematic fashion moving from our standard 50% to almost 90% BIMA use, we faced with the reality that the systematic adoption of these technical modifications can lead to suboptimal results. In 89% of our BIMA patients, we used the Y graft. This technical solution was necessary to reach distal target vessels and maximize the completeness of revascularization. The Y graft is known to have complex flow dynamics and to be more sensitive to flow competition and flow diversion when compared with the in situ graft [17]. It is conceivable to hypothesize that the risk of graft occlusion is higher when systematically using the Y graft rather than the insitu configuration for BIMA. In fact, the safety of the Y graft has been demonstrated by 1 randomized trial and observational studies [18–20]. However, in none of these studies, the Y configuration was used on a systematic basis. In Glineur’s randomized trial, only 23.4% (301 of 1297) of the overall CABG population was considered eligible and randomized for the trial [18]. In our series, all graft failures were observed in Y grafts, suggesting that the routine and unrestricted adoption of this configuration can jeopardize patency. It is possible that our results would have been different with a more extensive use of the insitu BIMA. On the other hand, the use of the Y graft was often mandate by the necessity to graft distal or multiple targets. A special note of concern is the very high incidence of sternal complications, in particular, in diabetics. Ten of the 11 patients who had sternal complications were in fact diabetics, and of them, 6 were also obese. Sternal complications were the most frequent adverse event in the CATHEXIS series and were the major determinant of the statistical difference in postoperative outcome between groups. The results of the ART are similar to ours in reporting a significantly higher incidence of sternal complications in the BIMA series [16]. The use of the radial artery as the second arterial conduit makes the use of multiple arterial grafts technically easier and safer in terms of sternal complications. Technically, the radial artery is very similar to a vein graft, and because of its superior length and diameter and thicker wall, it is much more versatile and easy to use than the second mammary. Clearly, harvesting of the radial artery does not increase the risk of sternal complications. It is likely that with an extensive use of both the radial artery and the right mammary, a percentage of use of the second arterial graft similar to that reported in the CATHEXIS can be achieved without the increase in the operative risk seen in the ART and in the CATHEXIS. The fact that at 5 years the ART did not show any clinical benefit for the addition of a second mammary graft [16], while a posthoc analysis found that the use of the radial artery to supplement single and double mammaries was associated with a lower risk for mid-term major adverse cardiac events [21] and the high crossover rate in the BIMA group in the ART seems to support this hypothesis. Limitations Several limitations of this study must be acknowledged. The CATHEXIS was an observational registry whose primary aim was to show feasibility. Hence, no formal sample size calculation was performed for the comparison between BIMA and the previous revascularization strategy. The use of propensity matching cannot account for unmeasured confounding and propensity matched observational studies are far less rigorous than randomized trials. Also, the comparison of consecutive cohorts instead of contemporary cohorts of patients has intrinsic limitations. The lack of follow-up data is another limitation of this study. Finally, the reported findings reflect our own experience. The results can be different for other surgeons. CONCLUSION In conclusion, in our study, the systematic and unrestricted use of BIMA was associated with a high incidence of perioperative adverse events (particularly sternal complications). Individualization of the revascularization strategy to the patient and combined use of alternative arterial conduits (in particular the radial artery) are probably preferable to systematic use of BIMA. SUPPLEMENTARY MATERIAL Supplementary material is available at EJCTS online. Conflict of interest: none declared. REFERENCES 1 Hillis LD, Smith PK, Anderson JL, Bittl JA, Bridges CR, Byrne JG. 2011 ACCF/AHA guideline for coronary artery bypass graft surgery: executive summary: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Thorac Cardiovasc Surg  2012; 143: 4– 34. Google Scholar CrossRef Search ADS PubMed  2 Kolh P, Windecker S, Alfonso F, Collet J-P, Cremer J, Falk V et al.   2014 ESC/EACTS guidelines on myocardial revascularization: the task force on myocardial revascularization of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS). Developed with the special contribution of the European Association of Percutaneous Cardiovascular Interventions (EAPCI). Eur J Cardiothorac Surg  2014; 46: 517– 92. Google Scholar CrossRef Search ADS PubMed  3 Aldea GS, Bakaeen FG, Pal J, Fremes S, Head SJ, Sabik J et al.   The Society of Thoracic Surgeons clinical practice guidelines on arterial conduits for coronary artery bypass grafting. Ann Thorac Surg  2016; 101: 801– 9. Google Scholar CrossRef Search ADS PubMed  4 Kinoshita T, Asai T, Suzuki T, Kambara A, Matsubayashi K. Off-pump bilateral versus single skeletonized internal thoracic artery grafting in high-risk patients. Circulation  2011; 124: S130– 4. Google Scholar CrossRef Search ADS PubMed  5 Bonacchi M, Maiani M, Prifti E, Di Eusanio G, Di Eusanio M, Leacche M. Urgent/emergent surgical revascularization in unstable angina: influence of different type of conduits. J Cardiovasc Surg (Torino)  2006; 47: 201– 10. Google Scholar PubMed  6 Gansera B, Schmidtler F, Gillrath G, Angelis I, Wenke K, Weingartner J et al.   Does bilateral ITA grafting increase perioperative complications? Outcome of 4462 patients with bilateral versus 4204 patients with single ITA bypass. Eur J Cardiothorac Surg  2006; 30: 318– 23. Google Scholar CrossRef Search ADS PubMed  7 Rizzoli G, Schiavon L, Bellini P. Does the use of bilateral internal mammary artery (IMA) grafts provide incremental benefit relative to the use of a single IMA graft? A meta-analysis approach. Eur J Cardiothorac Surg  2002; 22: 781– 6. Google Scholar CrossRef Search ADS PubMed  8 Taggart DP, D’Amico R, Altman DG. Effect of arterial revascularisation on survival: a systematic review of studies comparing bilateral and single internal mammary arteries. Lancet  2001; 358: 870– 5. Google Scholar CrossRef Search ADS PubMed  9 Wijns W, Kolh P, Danchin N, Di Mario C. Guidelines on myocardial revascularization: task force on myocardial revascularization of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS), European Association for Percutaneous Cardiovascular Interventions (EAPCI). Eur Heart J  2010; 31: 2501– 55. Google Scholar CrossRef Search ADS PubMed  10 Thygesen K, Alpert JS, White HD, Jaffe AS, Apple FS, Galvani M et al.   Universal definition of myocardial infarction. Circulation  2007; 116: 2634– 53. Google Scholar CrossRef Search ADS PubMed  11 Gaudino M, Nesta M, Burzotta F, Trani C, Coluccia V, Crea F et al.   Results of emergency postoperative re-angiography after cardiac surgery procedures. Ann Thorac Surg  2015; 99: 1576– 82. Google Scholar CrossRef Search ADS PubMed  12 Gaudino M, Cellini C, Pragliola C, Trani C, Burzotta F, Schiavoni G et al.   Arterial versus venous bypass grafts in patients with in-stent restenosis. Circulation  2005; 112: I265– 9. Google Scholar CrossRef Search ADS PubMed  13 Possati G, Gaudino M, Prati F, Alessandrini F, Trani C, Glieca F et al.   Long-term results of the radial artery used for myocardial revascularization. Circulation  2003; 108: 1350– 4. Google Scholar CrossRef Search ADS PubMed  14 Gaudino M, Glieca F, Luciani N, Alessandrini F, Possati G. Clinical and angiographic effects of chronic calcium channel blocker therapy continued beyond first postoperative year in patients with radial artery grafts: results of a prospective randomized investigation. Circulation  2001; 104: I64– 7. Google Scholar CrossRef Search ADS PubMed  15 Dalén M, Ivert T, Holzmann MJ, Sartipy U. Bilateral versus single internal mammary coronary artery bypass grafting in Sweden from 1997–2008. PLoS One  2014; 9: e86929. Google Scholar CrossRef Search ADS PubMed  16 Taggart DP, Altman DG, Gray AM, Lees B, Gerry S, Benedetto U et al.   Randomized trial of bilateral versus single internal-thoracic-artery grafts. N Engl J Med  2016; 375: 2540– 9. Google Scholar CrossRef Search ADS PubMed  17 Nakajima H, Kobayashi J, Toda K, Fujita T, Shimahara Y, Kasahara Y et al.   Angiographic evaluation of flow distribution in sequential and composite arterial grafts for three vessel disease. Eur J Cardiothorac Surg  2012; 41: 763– 9. Google Scholar CrossRef Search ADS PubMed  18 Glineur D, Hanet C, Poncelet A, D’Hoore W, Funken J-C, Rubay J et al.   Comparison of bilateral internal thoracic artery revascularization using in situ or Y graft configurations: a prospective randomized clinical, functional, and angiographic midterm evaluation. Circulation  2008; 118: S216– 21. Google Scholar CrossRef Search ADS PubMed  19 Barner HB, Sundt TM, Bailey M, Zang Y. Midterm results of complete arterial revascularization in more than 1, 000 patients using an internal thoracic artery/radial artery T graft. Ann Surg  2001; 234: 447– 53. Google Scholar CrossRef Search ADS PubMed  20 Yanagawa B, Verma S, Jüni P, Tam DY, Mazine A, Puskas JD et al.   A systematic review and meta-analysis of in situ versus composite bilateral internal thoracic artery grafting. J Thorac Cardiovasc Surg  2017; 153: 1108– 16.e16. Google Scholar CrossRef Search ADS PubMed  21 Taggart DP, Altman DG, Flather M, Gerry S, Gray A, Lees B et al.   Associations between adding a radial artery graft to single and bilateral internal thoracic artery grafts and outcomes: insights from the arterial revascularization trial. Circulation  2017; 136: 454– 63. Google Scholar CrossRef Search ADS PubMed  © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png European Journal of Cardio-Thoracic Surgery Oxford University Press

Loading next page...
 
/lp/ou_press/systematic-bilateral-internal-mammary-artery-grafting-lessons-learned-jRPbHtxSat
Publisher
Oxford University Press
Copyright
© The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
ISSN
1010-7940
eISSN
1873-734X
D.O.I.
10.1093/ejcts/ezy148
Publisher site
See Article on Publisher Site

Abstract

Abstract OBJECTIVES Despite claims of feasibility, to date no study has examined the effect of systematic bilateral internal mammary artery (BIMA) use in a large cohort of real-world unselected patients. The CATHolic University EXtensive BIMA Grafting Study (CATHEXIS) registry was designed to assess the feasibility and safety of systematic BIMA grafting. METHODS The CATHEXIS was a single-centre, prospective, observational, propensity-matched study. The study was supposed to include 2 arms of 500 patients each: a prospective arm and a retrospective arm. The prospective arm included almost all patients referred for coronary artery bypass grafting (CABG) at our institution after the start of the CATHEXIS with very few exceptions. BIMA would have been used in all these patients. The retrospective arm included patients submitted to CABG before the start of the CATHEXIS and propensity matched to the prospective group (average BIMA use 50%; the radial artery was extensively used). Safety analyses were scheduled after enrolment of 200, 300 and 400 BIMA patients. RESULTS After the first 226 patients, the BIMA use percentage was 88.5% (200 of 226). In 178 (89%) patients, mammary arteries were used as Y graft. Postoperative mortality was 2%, and incidence of perioperative myocardial infarction, graft failure and sternal complications were 3.5%, 3% and 5.5%, respectively. No perioperative stroke occurred. The incidence of major adverse cardiac events (particularly graft failure and sternal complications) in the BIMA arm were significantly higher than those in the propensity-matched cohort; the study was stopped for safety. CONCLUSIONS In a real world setting the systematic use of BIMA was associated with a higher incidence of perioperative adverse events (particularly sternal complications). Individualization of the revascularization strategy and use of alternative arterial conduits are probably preferable to systematic use of BIMA. Coronary artery bypass grafting , Bilateral internal mammary artery , Coronary artery disease INTRODUCTION Despite several guidelines and position papers recommending a wider use of bilateral internal mammary arteries (BIMAs) [1–3], no study has been published on the feasibility of systematic BIMA use. In all the published studies, the use of BIMA has been restricted to a portion of the overall population, and the BIMA group has in some way been selected by the operating surgeons. In October 2012, we started a complete re-engineering of our institutional strategy for coronary artery bypass grafting (CABG) surgery towards a systematic adoption of BIMA grafting. At that time, the evidence of the clinical benefits associated with BIMA use was even more solid than today. The literature was almost unanimously concordant in reporting that BIMA use did not increase operative mortality and morbidity, even in subgroups of high-risk patients [4–6]. A very large body of observational evidence summarized in 2 independent meta-analyses showed significant long-term survival benefit using BIMA for CABG, without adverse effect in terms of mortality [7, 8]. According to the 2010 Guidelines of the Task Force on Myocardial Revascularization of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS), complete revascularization with arterial grafts was a Class IA recommendation for patients with reasonable life expectancy [9]. Our centre had a very solid tradition with the use of arterial grafts for CABG, and at that time, approximately 70–80% of our patients referred for non-emergent CABG received more than 1 arterial graft. BIMA was used in almost half of the cases, and the radial artery was extensively used. Despite our good results, the evidence supporting the use of BIMA was clearly superior to that supporting the radial artery. On this basis, we decided to progressively adopt systematic BIMA grafting in every patient referred to our institution who met the criteria depicted in guidelines. The CATHolic University EXtensive BIMA Grafting Study (CATHEXIS) registry was designed to record this transition and to assess the feasibility and safety of systematic use of BIMA for treatment of multivessel coronary artery disease in an unrestricted consecutive cohort of patients undergoing CABG at a large academic cardiac surgery department. After an initial phase of progressive increase in the rate of BIMA use, the CATHEXIS was started on 16 April 2012. We herein report our results. MATERIALS AND METHODS Study design The CATHEXIS was an observational, non-randomized single-centre study started on 16 April 2012 at the Department of Cardiovascular Medicine of the Catholic University of Rome (ClinicalTrials.gov, identifier NTC01593865). The trial was aimed at prospectively including 500 patients undergoing primary non-emergent isolated multivessel CABG with BIMA and to compare them with a retrospective cohort of 500 historic propensity-matched controls. Exclusion criteria were emergency status, previous cardiac operation, associated cardiac procedures other than CABG, preoperative left ventricular ejection fraction <30% and expected life expectancy <5 years. End points The primary end point of the CATHEXIS was to assess whether systematic BIMA grafting was feasible as a routine intervention in the clinical practice of a large academic cardiac surgery centre. Systematic BIMA grafting would have been considered feasible if the trial inclusion rate (number of BIMA patients versus total number of eligible patients) would have been ≥80% during the study period. As there was already solid evidence on the safety of BIMA and based on the available literature, our study was underpowered to detect differences in clinical outcomes, we considered safety a secondary end point. The secondary end point of the CATHEXIS was to evaluate differences in the rate of major adverse cardiac events (death, acute myocardial infarction, graft failure) and in the rate of sternotomy-related complications between the CATHEXIS patients and a control retrospective CABG group. A first interim efficacy analysis was planned after enrolment of the first 100 BIMA patients, and safety analyses were scheduled after enrolment of 200, 300 and 400 BIMA patients. Because of the observational nature of the study and the fact that the intervention was a Class IA recommendation according to the contemporary guidelines, no specific consent to participate in the CATHEXIS was requested. All patients consented to the surgical procedure and data collection. Patient groups The prospective arm (BIMA Group) was supposed to enrol 500 consecutive patients undergoing CABG with BIMA. The eligibility and the best revascularization strategy in each patient were assessed by the local Heart Team on the basis of clinical and anatomical conditions. The retrospective group (pre-CATHEXIS group) was designed to consist of 500 consecutive, historical control patients who received standard CABG from March 2012 going backwards. For this analysis, the control group consisted of patients operated on between January 2009 and March 2012. The percentage of BIMA use in this group was approximately 50% (Supplementary Material, Fig. S1). Data collection The data of patients in the BIMA study group were prospectively recorded in a datasheet divided into a preoperative section, an intraoperative section and a postoperative section. The preoperative data included age, gender, weight, height, body mass index (BMI), the presence of renal failure (defined as serum creatinine level >2.0 mg/dl), diabetes (defined as glucose blood levels >126 mg/dl or antidiabetic therapy) or chronic obstructive pulmonary disease, left ventricular ejection fraction (measured by Simpson rule using 2-dimensional echocardiography) and the logistic EuroSCORE. Obesity was defined as BMI >30 kg/m2. The intraoperative data included total operative time (from skin incision to skin closure), cardiopulmonary bypass time, cross-clamping time, type of conduits used, their configuration and coronary targets; for each bypass mean flow, pulsatility index and backward flow, measured by intraoperative transit-time flowmetry, were recorded. The postoperative data included bleeding in the first 24 h, the need for blood transfusion, type and number of postoperative complications and duration of the intensive care unit stay and in-hospital stay. Postoperative myocardial infarction was defined according to the universal definition in use at that time [10]. The same data were collected for patients included in the retrospective control group of patients from the electronic database of our hospital. Data of the control group were also prospectively collected. Per institutional protocols, we are very aggressive in performing control reangiography in the postoperative period [11]. Clinical, laboratory, ECG or echocardiographic evidence of ischaemia, as well as arrhythmias, prolonged low cardiac output, and marginal results at intraoperative flowmetric evaluation were indication for reangiography. Surgical technique All cases were operated using full median sternotomy, normothermic cardiopulmonary bypass, single aortic clamping and isothermic, intermittent, antegrade blood cardioplegia. Internal mammary arteries were harvested skeletonized and used to graft the main target vessels. Additional radial artery or saphenous vein grafts were used to complete revascularization. The 2 mammary arteries were used either in situ or as a Y graft depending on the anatomy of the coronary arteries and the surgeon’s intraoperative choice. The use of sequentials, double Y grafts and alternative inflow sources were also allowed. Intraoperative flowmetric evaluation was used in all cases. Statistical analysis Demographic and clinical data are presented as frequency distributions and simple percentages. Values of continuous variables are expressed as mean ± standard deviation. For propensity matching, a propensity score was generated for each patient from a multivariable logistic regression model based on the following preoperative covariates: age, gender, diabetes, chronic pulmonary disease, renal insufficiency, obesity, preoperative ejection fraction and EuroSCORE, with treatment type (control versus the CATHEXIS) as a binary dependent variable. The resulting propensity score represented the probability that a patient underwent BIMA grafting. BIMA patients were then matched to the standard CABG patients in a 1:1 ratio using a Rosenbaum optimal matching algorithm and a caliper size of 0.05. This approach minimized the overall distance between observations and was conducted using the Mahalanobis distance within propensity score calipers (no matches outside the calipers). The quality of the match was assessed using standardized difference. To assess differences in matched cohorts, the McNemar test was used to test categorical variables and paired t-test for continuous variables. All analyses were performed using the Number Cruncher Statistical Systems software (Version 8, Copyright 2012, NCSS, Kaysville, UT, USA) and Stata (Version 12, Copyright 2012, StataCorp LP, College Station, TX, USA). RESULTS From 16 April 2012 to 14 March 2013, 226 patients matching the inclusion criteria were referred to our centre. Of these, 11 (4.9%) patients were excluded preoperatively due to anatomical considerations on the status and quality of the target vessels. Another 15 (6.6%) patients were excluded intraoperatively for technical problems or considerations related to the quality of the conduits or the target vessels. Two hundred patients of the 226 (88.5%) patients received BIMA. Demographic characteristics The demographic and clinical characteristics of the 200 BIMA patients are listed in Table 1. The mean age was 66 ± 9 years, and the great majority of patients were men. The mean preoperative ejection fraction was 56 ± 8%, and the mean preoperative EuroSCORE was 3.7 ± 3.9. Table 1: Preoperative data of the 200 CATHEXIS patients Mean age, mean ± SD (range)  66 ± 9 (42–82)  Male, n (%)  183 (91.5)  Diabetes, n (%)  71 (35.5)  Chronic pulmonary disease, n (%)  13 (6.5)  Peripheral vascular disease, n (%)  11 (5.5)  Hypertension, n (%)  87 (43.5)  Dyslipidaemia, n (%)  91 (45.5)  Obesity, n (%)  38 (19)  Renal insufficiency, n (%)  6 (3)  Coronary disease, n (%)     Left main  19 (9.5)   3-vessel disease  148 (74)   2-vessel disease  33 (16.5)  Preoperative LVEF, mean ± SD (range)  56.1 ± 7.7 (34–71)  Mean EuroSCORE, mean ± SD  3.7 ± 3.9  Mean age, mean ± SD (range)  66 ± 9 (42–82)  Male, n (%)  183 (91.5)  Diabetes, n (%)  71 (35.5)  Chronic pulmonary disease, n (%)  13 (6.5)  Peripheral vascular disease, n (%)  11 (5.5)  Hypertension, n (%)  87 (43.5)  Dyslipidaemia, n (%)  91 (45.5)  Obesity, n (%)  38 (19)  Renal insufficiency, n (%)  6 (3)  Coronary disease, n (%)     Left main  19 (9.5)   3-vessel disease  148 (74)   2-vessel disease  33 (16.5)  Preoperative LVEF, mean ± SD (range)  56.1 ± 7.7 (34–71)  Mean EuroSCORE, mean ± SD  3.7 ± 3.9  LVEF: left ventricular ejection fraction; SD: standard deviation. Table 1: Preoperative data of the 200 CATHEXIS patients Mean age, mean ± SD (range)  66 ± 9 (42–82)  Male, n (%)  183 (91.5)  Diabetes, n (%)  71 (35.5)  Chronic pulmonary disease, n (%)  13 (6.5)  Peripheral vascular disease, n (%)  11 (5.5)  Hypertension, n (%)  87 (43.5)  Dyslipidaemia, n (%)  91 (45.5)  Obesity, n (%)  38 (19)  Renal insufficiency, n (%)  6 (3)  Coronary disease, n (%)     Left main  19 (9.5)   3-vessel disease  148 (74)   2-vessel disease  33 (16.5)  Preoperative LVEF, mean ± SD (range)  56.1 ± 7.7 (34–71)  Mean EuroSCORE, mean ± SD  3.7 ± 3.9  Mean age, mean ± SD (range)  66 ± 9 (42–82)  Male, n (%)  183 (91.5)  Diabetes, n (%)  71 (35.5)  Chronic pulmonary disease, n (%)  13 (6.5)  Peripheral vascular disease, n (%)  11 (5.5)  Hypertension, n (%)  87 (43.5)  Dyslipidaemia, n (%)  91 (45.5)  Obesity, n (%)  38 (19)  Renal insufficiency, n (%)  6 (3)  Coronary disease, n (%)     Left main  19 (9.5)   3-vessel disease  148 (74)   2-vessel disease  33 (16.5)  Preoperative LVEF, mean ± SD (range)  56.1 ± 7.7 (34–71)  Mean EuroSCORE, mean ± SD  3.7 ± 3.9  LVEF: left ventricular ejection fraction; SD: standard deviation. Perioperative data The mean number of grafts, arterial grafts and grafts with mammary artery per patient was 2.60 ± 0.70, 2.40 ± 0.72 and 2.38 ± 0.65, respectively. In 178 (89%) patients, the mammary arteries were used in Y graft configuration. Total arterial revascularization was obtained in 138 (69%) cases. Table 2 shows the targets of the internal mammary arteries and Table 3 the results of the intraoperative flow evaluation. Table 2: Targets of the mammary arteries in the CATHEXIS patients   n (%)  LIMA     LAD  158 (79)   D-LAD  25 (12.5)   OM  17 (8.5)  RIMA     OM  134 (67)   OM-PDA  20 (10)   OM-PL  8 (4)   OM2-OM1  4 (2)   PL  2 (1)   LAD  10 (5)   D  10 (5)   D-LAD  4 (2)   AL  7 (3.5)   AL-PL-PDA  1 (0.5)    n (%)  LIMA     LAD  158 (79)   D-LAD  25 (12.5)   OM  17 (8.5)  RIMA     OM  134 (67)   OM-PDA  20 (10)   OM-PL  8 (4)   OM2-OM1  4 (2)   PL  2 (1)   LAD  10 (5)   D  10 (5)   D-LAD  4 (2)   AL  7 (3.5)   AL-PL-PDA  1 (0.5)  AL: anterolateral branch; D: diagonal branch; LAD: left anterior descending artery; LIMA: left internal mammary artery; OM: obtuse marginal artery; PDA: posterior interventricular artery; PL: posterolateral branch; RCA: right coronary artery; RIMA: right internal mammary artery. Table 2: Targets of the mammary arteries in the CATHEXIS patients   n (%)  LIMA     LAD  158 (79)   D-LAD  25 (12.5)   OM  17 (8.5)  RIMA     OM  134 (67)   OM-PDA  20 (10)   OM-PL  8 (4)   OM2-OM1  4 (2)   PL  2 (1)   LAD  10 (5)   D  10 (5)   D-LAD  4 (2)   AL  7 (3.5)   AL-PL-PDA  1 (0.5)    n (%)  LIMA     LAD  158 (79)   D-LAD  25 (12.5)   OM  17 (8.5)  RIMA     OM  134 (67)   OM-PDA  20 (10)   OM-PL  8 (4)   OM2-OM1  4 (2)   PL  2 (1)   LAD  10 (5)   D  10 (5)   D-LAD  4 (2)   AL  7 (3.5)   AL-PL-PDA  1 (0.5)  AL: anterolateral branch; D: diagonal branch; LAD: left anterior descending artery; LIMA: left internal mammary artery; OM: obtuse marginal artery; PDA: posterior interventricular artery; PL: posterolateral branch; RCA: right coronary artery; RIMA: right internal mammary artery. Table 3: Results of intraoperative flow evaluation in the CATHEXIS patients   Flow (ml/min)  Pulsatility index  Y graft main  57.09 (41.52–75.29)  1.97 (1.34–2.69)  LIMA  45.79 (29.73–61.71)  2.11 (1.33–3.01)  RIMA  32.51 (20.31–46.16)  2.71 (1.20–4.25)    Flow (ml/min)  Pulsatility index  Y graft main  57.09 (41.52–75.29)  1.97 (1.34–2.69)  LIMA  45.79 (29.73–61.71)  2.11 (1.33–3.01)  RIMA  32.51 (20.31–46.16)  2.71 (1.20–4.25)  Values are presented as median (lower quartile interval–upper quartile interval). LIMA: left internal mammary artery; RIMA: right internal mammary artery. Table 3: Results of intraoperative flow evaluation in the CATHEXIS patients   Flow (ml/min)  Pulsatility index  Y graft main  57.09 (41.52–75.29)  1.97 (1.34–2.69)  LIMA  45.79 (29.73–61.71)  2.11 (1.33–3.01)  RIMA  32.51 (20.31–46.16)  2.71 (1.20–4.25)    Flow (ml/min)  Pulsatility index  Y graft main  57.09 (41.52–75.29)  1.97 (1.34–2.69)  LIMA  45.79 (29.73–61.71)  2.11 (1.33–3.01)  RIMA  32.51 (20.31–46.16)  2.71 (1.20–4.25)  Values are presented as median (lower quartile interval–upper quartile interval). LIMA: left internal mammary artery; RIMA: right internal mammary artery. The mean ± standard deviation operating time, clamping time and cardiopulmonary bypass time were 277 ± 44, 53 ± 16, 64 ± 17 min, respectively. Postoperative data The main postoperative complications are shown in Table 4. Four patients died: 2 due to multiorgan failure, 1 due to arrhythmia and 1 due to perioperative myocardial infarction. Table 4: Postoperative course of the 200 CATHEXIS patients Death, n (%)  4 (2)  Atrial fibrillation, n (%)  45 (22.5)  Myocardial infarction, n (%)  7 (3.5)  Reintervention for bleeding, n (%)  7 (3.5)  Prolonged ventilatory support, n (%)  6 (3)  Delirium, n (%)  1 (0.5)  Graft failure, n (%)  6 (3)  Sternal complications, n (%)  11 (5.5)  Death, n (%)  4 (2)  Atrial fibrillation, n (%)  45 (22.5)  Myocardial infarction, n (%)  7 (3.5)  Reintervention for bleeding, n (%)  7 (3.5)  Prolonged ventilatory support, n (%)  6 (3)  Delirium, n (%)  1 (0.5)  Graft failure, n (%)  6 (3)  Sternal complications, n (%)  11 (5.5)  Table 4: Postoperative course of the 200 CATHEXIS patients Death, n (%)  4 (2)  Atrial fibrillation, n (%)  45 (22.5)  Myocardial infarction, n (%)  7 (3.5)  Reintervention for bleeding, n (%)  7 (3.5)  Prolonged ventilatory support, n (%)  6 (3)  Delirium, n (%)  1 (0.5)  Graft failure, n (%)  6 (3)  Sternal complications, n (%)  11 (5.5)  Death, n (%)  4 (2)  Atrial fibrillation, n (%)  45 (22.5)  Myocardial infarction, n (%)  7 (3.5)  Reintervention for bleeding, n (%)  7 (3.5)  Prolonged ventilatory support, n (%)  6 (3)  Delirium, n (%)  1 (0.5)  Graft failure, n (%)  6 (3)  Sternal complications, n (%)  11 (5.5)  There were 7 (3.5%) perioperative myocardial infarctions. No postoperative stroke occurred. Other complications were atrial fibrillation (22.5%) and reoperation for bleeding (3.5%). Nine patients were submitted to control reangiography before discharge. Six of them (3% of the overall BIMA cohort) underwent percutaneous intervention due to graft failure. The culprit graft was always the left or right branch of the Y graft. In the remaining 3 cases, the angiographic findings were occlusion of an ungrafted coronary artery, diffuse coronary artery spasm and normal findings (1 case each). Mean stay in the intensive care unit and hospital after surgery was 2.55 ± 1.86 and 7.32 ± 4.00 days, respectively. Sternal wound complications occurred in 11 (5.5%) patients. Ten of them were diabetics (6 insulin dependent and 4 non-insulin dependent), so that the incidence of sternal complications in diabetics was 14% (10 of 71). Eight sternal complications (4%) were deep (involving the sternum), whereas the remaining 3 were superficial (limited to skin and subcutaneous tissue). Mean hospital stay for patient with sternal complications was 30 ± 14 days. Data of the unmatched control population are given in the Supplementary Material, Table S1. Propensity matching led to 2 groups of 150 pairs with minimal residual imbalance (Table 5). The Y graft was used in 137 (91.3%) patients in the CATHEXIS group and in 38 (25.3%) in the control group (P < 0.001). When compared with patients operated in the pre-CATHEXIS era, BIMA patients had higher (although not significantly) rates of death and myocardial infarction and a significantly higher incidence of graft failure, sternal complications and major cardiac events (Table 6). In the control group, no patients had to be submitted to control reangiography. Table 5: Preoperative data of the 150 matched pairs   CATHEXIS patients  Control patients  Standardized difference  Mean age, mean ± SD  65.1 ± 7.3  64.5 ± 8.2  0.03  Male, n (%)  135 (90)  133 (88.6)  0.02  Diabetes, n (%)  64 (42.6)  65 (43.3)  0.01  Chronic pulmonary disease, n (%)  7 (4.6)  5 (3.3)  0.03  Peripheral vascular disease, n (%)  9 (6.0)  8 (5.3)  0.02  Hypertension, n (%)  69 (46)  70 (46.6)  0.02  Dyslipidaemia, n (%)  72 (48)  71 (47.3)  0.02  Obesity, n (%)  26 (17.3)  22 (14.6)  0.03  Renal insufficiency, n (%)  5 (3.3)  7 (4.6)  0.03  Preoperative LVEF, mean ± SD  55.2 ± 5.8  54.1 ± 5.5  0.07  Mean EuroSCORE, mean ± SD  3.9 ± 3.1  3.8 ± 2.9  0.02    CATHEXIS patients  Control patients  Standardized difference  Mean age, mean ± SD  65.1 ± 7.3  64.5 ± 8.2  0.03  Male, n (%)  135 (90)  133 (88.6)  0.02  Diabetes, n (%)  64 (42.6)  65 (43.3)  0.01  Chronic pulmonary disease, n (%)  7 (4.6)  5 (3.3)  0.03  Peripheral vascular disease, n (%)  9 (6.0)  8 (5.3)  0.02  Hypertension, n (%)  69 (46)  70 (46.6)  0.02  Dyslipidaemia, n (%)  72 (48)  71 (47.3)  0.02  Obesity, n (%)  26 (17.3)  22 (14.6)  0.03  Renal insufficiency, n (%)  5 (3.3)  7 (4.6)  0.03  Preoperative LVEF, mean ± SD  55.2 ± 5.8  54.1 ± 5.5  0.07  Mean EuroSCORE, mean ± SD  3.9 ± 3.1  3.8 ± 2.9  0.02  LVEF: left ventricular ejection fraction; SD: standard deviation. Table 5: Preoperative data of the 150 matched pairs   CATHEXIS patients  Control patients  Standardized difference  Mean age, mean ± SD  65.1 ± 7.3  64.5 ± 8.2  0.03  Male, n (%)  135 (90)  133 (88.6)  0.02  Diabetes, n (%)  64 (42.6)  65 (43.3)  0.01  Chronic pulmonary disease, n (%)  7 (4.6)  5 (3.3)  0.03  Peripheral vascular disease, n (%)  9 (6.0)  8 (5.3)  0.02  Hypertension, n (%)  69 (46)  70 (46.6)  0.02  Dyslipidaemia, n (%)  72 (48)  71 (47.3)  0.02  Obesity, n (%)  26 (17.3)  22 (14.6)  0.03  Renal insufficiency, n (%)  5 (3.3)  7 (4.6)  0.03  Preoperative LVEF, mean ± SD  55.2 ± 5.8  54.1 ± 5.5  0.07  Mean EuroSCORE, mean ± SD  3.9 ± 3.1  3.8 ± 2.9  0.02    CATHEXIS patients  Control patients  Standardized difference  Mean age, mean ± SD  65.1 ± 7.3  64.5 ± 8.2  0.03  Male, n (%)  135 (90)  133 (88.6)  0.02  Diabetes, n (%)  64 (42.6)  65 (43.3)  0.01  Chronic pulmonary disease, n (%)  7 (4.6)  5 (3.3)  0.03  Peripheral vascular disease, n (%)  9 (6.0)  8 (5.3)  0.02  Hypertension, n (%)  69 (46)  70 (46.6)  0.02  Dyslipidaemia, n (%)  72 (48)  71 (47.3)  0.02  Obesity, n (%)  26 (17.3)  22 (14.6)  0.03  Renal insufficiency, n (%)  5 (3.3)  7 (4.6)  0.03  Preoperative LVEF, mean ± SD  55.2 ± 5.8  54.1 ± 5.5  0.07  Mean EuroSCORE, mean ± SD  3.9 ± 3.1  3.8 ± 2.9  0.02  LVEF: left ventricular ejection fraction; SD: standard deviation. Table 6: Postoperative course of the 150 matched pairs   CATHEXIS patients, n (%)  Control patients, n (%)  P-value  BIMA use  150 (100)  66 (44)  0.001  Use of 2 arterial grafts  150 (100)  122 (81.3)  <0.001  Death  3 (2)  1 (0.6)  0.31  Myocardial infarction  4 (2.6)  1 (0.6)  0.17  Graft failure  4 (2.6)  0  0.044  Sternal complications  9 (6)  2 (1.3)  0.031  Stroke  0  1 (0.6)  0.31  MACE  11 (7.3)  2 (1.3)  0.010    CATHEXIS patients, n (%)  Control patients, n (%)  P-value  BIMA use  150 (100)  66 (44)  0.001  Use of 2 arterial grafts  150 (100)  122 (81.3)  <0.001  Death  3 (2)  1 (0.6)  0.31  Myocardial infarction  4 (2.6)  1 (0.6)  0.17  Graft failure  4 (2.6)  0  0.044  Sternal complications  9 (6)  2 (1.3)  0.031  Stroke  0  1 (0.6)  0.31  MACE  11 (7.3)  2 (1.3)  0.010  BIMA: bilateral internal mammary artery; MACE: major adverse cardiac events (death, myocardial infarction, graft failure). Table 6: Postoperative course of the 150 matched pairs   CATHEXIS patients, n (%)  Control patients, n (%)  P-value  BIMA use  150 (100)  66 (44)  0.001  Use of 2 arterial grafts  150 (100)  122 (81.3)  <0.001  Death  3 (2)  1 (0.6)  0.31  Myocardial infarction  4 (2.6)  1 (0.6)  0.17  Graft failure  4 (2.6)  0  0.044  Sternal complications  9 (6)  2 (1.3)  0.031  Stroke  0  1 (0.6)  0.31  MACE  11 (7.3)  2 (1.3)  0.010    CATHEXIS patients, n (%)  Control patients, n (%)  P-value  BIMA use  150 (100)  66 (44)  0.001  Use of 2 arterial grafts  150 (100)  122 (81.3)  <0.001  Death  3 (2)  1 (0.6)  0.31  Myocardial infarction  4 (2.6)  1 (0.6)  0.17  Graft failure  4 (2.6)  0  0.044  Sternal complications  9 (6)  2 (1.3)  0.031  Stroke  0  1 (0.6)  0.31  MACE  11 (7.3)  2 (1.3)  0.010  BIMA: bilateral internal mammary artery; MACE: major adverse cardiac events (death, myocardial infarction, graft failure). On the basis of aforementioned data, the CATHEXIS was stopped for safety reasons on 14 March 2013. We went back to our pre-CATHEXIS grafting strategy. DISCUSSION We have a long-standing tradition in coronary surgery. In the early 90s, we pioneered the use of arterial grafts [12–14]. All the surgeons involved in the CATHEXIS had more than 10 years of experience with the use of BIMA. For some of them, the years of experience with BIMA were 15 or 20. The majority of us were using a second arterial graft in 70–80% of their CABG cases before starting the CATHEXIS, although often the second arterial graft was the radial artery. The available evidence at the time of the CATHEXIS was clearly supporting the safety and effectiveness of BIMA in improving postoperative outcomes [4–8], and according to the guidelines, complete revascularization with arterial grafts was a Class IA recommendation for patients with reasonable life expectancy [1, 2]. The evidence in support of the use of BIMA appeared more solid that the one in favour of the use of the radial artery and the routine use of BIMA had often been advocated. On this basis, we were confident that re-engineering our CABG strategy towards the systematic use of BIMA was a step in the right direction. After the CATHEXIS, we went back to a strategy for frequent use of the radial artery and careful individualization of the choice of the arterial conduits in accordance with the characteristics of a single patient. Our results went back to the pretrial era very quickly, and we were able to maintain the percentage of the use of a second arterial graft at approximately 80% of our CABG population. Although bad experiences with systematic BIMA use are often the subject of conversation in the hallways of national and international meetings, they are very rarely brought to the podium. To date, no study on systematic use of BIMA has been published. Indeed, in almost all of the existing studies, the operation has been reserved to a selected portion of the total of CABG cases. In a recent publication using the SWEDEHEART registry, the percentage of BIMA use in a nationwide real-world setting was 1% [15]. The process of preoperatively selecting the patients on the basis of their clinical and angiographic characteristics and the surgeon’s technical skill is probably the key in determining the safety and long-term results of BIMA. When this process is abandoned and BIMA becomes a per-protocol choice, safety can be jeopardized. The Arterial Revascularization Trial (ART) is the only large-scale study where the decision to use BIMA was based on the randomization process and not on the decision of the operating surgeon [16]. However, even in ART, only 28% of the patients who met the eligibility criteria were actually randomized, so that a process of preselection was clearly part of the study. Also, in ART, 16.4% of patients randomized to BIMA received a single mammary at surgery. This high percentage of crossover expresses the technical difficulty of systematically using BIMA. This is even more notable because in ART, the participating surgeons were selected based on their experience with BIMA grafting and were considered experts of the technique. In the CATHEXIS, 88.4% of the eligible patients received BIMA, and the crossover from BIMA to single mammary was 6.9%. There is no doubt that the use of BIMA substantially increases the technical complexity of the operation. In the majority of the cases, skilled surgeons with adequate experience can overcome the technical difficulties. In most situations, there are technical solutions to overcome length, calibre and geometric issues (although at the price of exponentially increasing complexity). The use of skeletonization, multiple sequentials, Y or double Y grafts and alternative inflow sources are part of this armamentarium and allow the use of BIMA in a selected majority of CABG cases. As a group, we were all familiar with these techniques. However, when we started using BIMA in a systematic fashion moving from our standard 50% to almost 90% BIMA use, we faced with the reality that the systematic adoption of these technical modifications can lead to suboptimal results. In 89% of our BIMA patients, we used the Y graft. This technical solution was necessary to reach distal target vessels and maximize the completeness of revascularization. The Y graft is known to have complex flow dynamics and to be more sensitive to flow competition and flow diversion when compared with the in situ graft [17]. It is conceivable to hypothesize that the risk of graft occlusion is higher when systematically using the Y graft rather than the insitu configuration for BIMA. In fact, the safety of the Y graft has been demonstrated by 1 randomized trial and observational studies [18–20]. However, in none of these studies, the Y configuration was used on a systematic basis. In Glineur’s randomized trial, only 23.4% (301 of 1297) of the overall CABG population was considered eligible and randomized for the trial [18]. In our series, all graft failures were observed in Y grafts, suggesting that the routine and unrestricted adoption of this configuration can jeopardize patency. It is possible that our results would have been different with a more extensive use of the insitu BIMA. On the other hand, the use of the Y graft was often mandate by the necessity to graft distal or multiple targets. A special note of concern is the very high incidence of sternal complications, in particular, in diabetics. Ten of the 11 patients who had sternal complications were in fact diabetics, and of them, 6 were also obese. Sternal complications were the most frequent adverse event in the CATHEXIS series and were the major determinant of the statistical difference in postoperative outcome between groups. The results of the ART are similar to ours in reporting a significantly higher incidence of sternal complications in the BIMA series [16]. The use of the radial artery as the second arterial conduit makes the use of multiple arterial grafts technically easier and safer in terms of sternal complications. Technically, the radial artery is very similar to a vein graft, and because of its superior length and diameter and thicker wall, it is much more versatile and easy to use than the second mammary. Clearly, harvesting of the radial artery does not increase the risk of sternal complications. It is likely that with an extensive use of both the radial artery and the right mammary, a percentage of use of the second arterial graft similar to that reported in the CATHEXIS can be achieved without the increase in the operative risk seen in the ART and in the CATHEXIS. The fact that at 5 years the ART did not show any clinical benefit for the addition of a second mammary graft [16], while a posthoc analysis found that the use of the radial artery to supplement single and double mammaries was associated with a lower risk for mid-term major adverse cardiac events [21] and the high crossover rate in the BIMA group in the ART seems to support this hypothesis. Limitations Several limitations of this study must be acknowledged. The CATHEXIS was an observational registry whose primary aim was to show feasibility. Hence, no formal sample size calculation was performed for the comparison between BIMA and the previous revascularization strategy. The use of propensity matching cannot account for unmeasured confounding and propensity matched observational studies are far less rigorous than randomized trials. Also, the comparison of consecutive cohorts instead of contemporary cohorts of patients has intrinsic limitations. The lack of follow-up data is another limitation of this study. Finally, the reported findings reflect our own experience. The results can be different for other surgeons. CONCLUSION In conclusion, in our study, the systematic and unrestricted use of BIMA was associated with a high incidence of perioperative adverse events (particularly sternal complications). Individualization of the revascularization strategy to the patient and combined use of alternative arterial conduits (in particular the radial artery) are probably preferable to systematic use of BIMA. SUPPLEMENTARY MATERIAL Supplementary material is available at EJCTS online. Conflict of interest: none declared. REFERENCES 1 Hillis LD, Smith PK, Anderson JL, Bittl JA, Bridges CR, Byrne JG. 2011 ACCF/AHA guideline for coronary artery bypass graft surgery: executive summary: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Thorac Cardiovasc Surg  2012; 143: 4– 34. Google Scholar CrossRef Search ADS PubMed  2 Kolh P, Windecker S, Alfonso F, Collet J-P, Cremer J, Falk V et al.   2014 ESC/EACTS guidelines on myocardial revascularization: the task force on myocardial revascularization of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS). Developed with the special contribution of the European Association of Percutaneous Cardiovascular Interventions (EAPCI). Eur J Cardiothorac Surg  2014; 46: 517– 92. Google Scholar CrossRef Search ADS PubMed  3 Aldea GS, Bakaeen FG, Pal J, Fremes S, Head SJ, Sabik J et al.   The Society of Thoracic Surgeons clinical practice guidelines on arterial conduits for coronary artery bypass grafting. Ann Thorac Surg  2016; 101: 801– 9. Google Scholar CrossRef Search ADS PubMed  4 Kinoshita T, Asai T, Suzuki T, Kambara A, Matsubayashi K. Off-pump bilateral versus single skeletonized internal thoracic artery grafting in high-risk patients. Circulation  2011; 124: S130– 4. Google Scholar CrossRef Search ADS PubMed  5 Bonacchi M, Maiani M, Prifti E, Di Eusanio G, Di Eusanio M, Leacche M. Urgent/emergent surgical revascularization in unstable angina: influence of different type of conduits. J Cardiovasc Surg (Torino)  2006; 47: 201– 10. Google Scholar PubMed  6 Gansera B, Schmidtler F, Gillrath G, Angelis I, Wenke K, Weingartner J et al.   Does bilateral ITA grafting increase perioperative complications? Outcome of 4462 patients with bilateral versus 4204 patients with single ITA bypass. Eur J Cardiothorac Surg  2006; 30: 318– 23. Google Scholar CrossRef Search ADS PubMed  7 Rizzoli G, Schiavon L, Bellini P. Does the use of bilateral internal mammary artery (IMA) grafts provide incremental benefit relative to the use of a single IMA graft? A meta-analysis approach. Eur J Cardiothorac Surg  2002; 22: 781– 6. Google Scholar CrossRef Search ADS PubMed  8 Taggart DP, D’Amico R, Altman DG. Effect of arterial revascularisation on survival: a systematic review of studies comparing bilateral and single internal mammary arteries. Lancet  2001; 358: 870– 5. Google Scholar CrossRef Search ADS PubMed  9 Wijns W, Kolh P, Danchin N, Di Mario C. Guidelines on myocardial revascularization: task force on myocardial revascularization of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS), European Association for Percutaneous Cardiovascular Interventions (EAPCI). Eur Heart J  2010; 31: 2501– 55. Google Scholar CrossRef Search ADS PubMed  10 Thygesen K, Alpert JS, White HD, Jaffe AS, Apple FS, Galvani M et al.   Universal definition of myocardial infarction. Circulation  2007; 116: 2634– 53. Google Scholar CrossRef Search ADS PubMed  11 Gaudino M, Nesta M, Burzotta F, Trani C, Coluccia V, Crea F et al.   Results of emergency postoperative re-angiography after cardiac surgery procedures. Ann Thorac Surg  2015; 99: 1576– 82. Google Scholar CrossRef Search ADS PubMed  12 Gaudino M, Cellini C, Pragliola C, Trani C, Burzotta F, Schiavoni G et al.   Arterial versus venous bypass grafts in patients with in-stent restenosis. Circulation  2005; 112: I265– 9. Google Scholar CrossRef Search ADS PubMed  13 Possati G, Gaudino M, Prati F, Alessandrini F, Trani C, Glieca F et al.   Long-term results of the radial artery used for myocardial revascularization. Circulation  2003; 108: 1350– 4. Google Scholar CrossRef Search ADS PubMed  14 Gaudino M, Glieca F, Luciani N, Alessandrini F, Possati G. Clinical and angiographic effects of chronic calcium channel blocker therapy continued beyond first postoperative year in patients with radial artery grafts: results of a prospective randomized investigation. Circulation  2001; 104: I64– 7. Google Scholar CrossRef Search ADS PubMed  15 Dalén M, Ivert T, Holzmann MJ, Sartipy U. Bilateral versus single internal mammary coronary artery bypass grafting in Sweden from 1997–2008. PLoS One  2014; 9: e86929. Google Scholar CrossRef Search ADS PubMed  16 Taggart DP, Altman DG, Gray AM, Lees B, Gerry S, Benedetto U et al.   Randomized trial of bilateral versus single internal-thoracic-artery grafts. N Engl J Med  2016; 375: 2540– 9. Google Scholar CrossRef Search ADS PubMed  17 Nakajima H, Kobayashi J, Toda K, Fujita T, Shimahara Y, Kasahara Y et al.   Angiographic evaluation of flow distribution in sequential and composite arterial grafts for three vessel disease. Eur J Cardiothorac Surg  2012; 41: 763– 9. Google Scholar CrossRef Search ADS PubMed  18 Glineur D, Hanet C, Poncelet A, D’Hoore W, Funken J-C, Rubay J et al.   Comparison of bilateral internal thoracic artery revascularization using in situ or Y graft configurations: a prospective randomized clinical, functional, and angiographic midterm evaluation. Circulation  2008; 118: S216– 21. Google Scholar CrossRef Search ADS PubMed  19 Barner HB, Sundt TM, Bailey M, Zang Y. Midterm results of complete arterial revascularization in more than 1, 000 patients using an internal thoracic artery/radial artery T graft. Ann Surg  2001; 234: 447– 53. Google Scholar CrossRef Search ADS PubMed  20 Yanagawa B, Verma S, Jüni P, Tam DY, Mazine A, Puskas JD et al.   A systematic review and meta-analysis of in situ versus composite bilateral internal thoracic artery grafting. J Thorac Cardiovasc Surg  2017; 153: 1108– 16.e16. Google Scholar CrossRef Search ADS PubMed  21 Taggart DP, Altman DG, Flather M, Gerry S, Gray A, Lees B et al.   Associations between adding a radial artery graft to single and bilateral internal thoracic artery grafts and outcomes: insights from the arterial revascularization trial. Circulation  2017; 136: 454– 63. Google Scholar CrossRef Search ADS PubMed  © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)

Journal

European Journal of Cardio-Thoracic SurgeryOxford University Press

Published: Apr 16, 2018

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off