Abstract OBJECTIVES The incidence of both solitary pulmonary nodules (SPN) and non-valvular atrial fibrillation (NVAF) has increased over the past decade. We performed concomitant video-assisted thoracoscopic surgery with modified epicardial radiofrequency ablation procedure for NVAF and SPN resection. METHODS Sixteen patients (7 men, mean age 62.6 ± 11.2 years) with SPN and NVAF underwent this procedure. Of these patients, 10 had paroxysmal atrial fibrillation and 6 persistent atrial fibrillation. A modified epicardial radiofrequency ablation combined with pulmonary vein isolation, circumferential left atrial ablation, ganglionic plexus ablation and left atrial appendage resection was performed for all patients. Left pulmonary surgery was carried out subsequently. RESULTS The mean procedure duration was 203.1 ± 15.6 (range 177–224) min. All patients successfully underwent this procedure with no conversion to sternotomy or pacemaker implantation. Of the 16 included patients, 13 received lobectomy and 3 received wedge resection. No severe complications occurred postoperatively. The mean length of hospital stay was 9.1 ± 1.4 (range 7–11) days with a mean follow-up period of 18.7 ± 6.7 (range 8–32) months. One patient had AF recurrence 6 months postoperatively. No pulmonary vein stenosis was detected at the 3rd postoperative month. There were no deaths or thromboembolic events during follow-up. CONCLUSIONS This concomitant therapy proved to be safe and yielded good clinical outcomes. Therefore, it deserves to be considered as a treatment for patients with SPN and NVAF. Solitary pulmonary nodule, Non-valvular atrial fibrillation, Thoracoscopic surgery INTRODUCTION A solitary pulmonary nodule (SPN) is defined as an approximately round lesion that is less than 3 cm in diameter and completely surrounded by pulmonary parenchyma in the absence of other abnormalities . During the past decade, patients in China have experienced increasing morbidity associated with SPN . Elective video-assisted thoracoscopic surgery (VATS) for SPN is associated with long-term patient survival. During the same period, the incidence of non-valvular atrial fibrillation (NVAF) has also risen . Patients with NVAF have higher rates of thrombosis, cardiovascular morbidity and all-cause mortality [4, 5]. A proportion of patients may have both SPN and NVAF. Without simultaneous treatment of NVAF, such patients would undergo staged pulmonary resection and atrial fibrillation (AF) ablation surgeries or receive lifelong anticoagulation and medical therapy. Although catheter ablation may be considered, the single-procedure success rate remains unsatisfactory. In contrast, VATS-assisted ablation for NVAF has demonstrated promising clinical outcomes but has not been suitable for patients with previous lung surgery. Therefore, we performed concomitant VATS with modified epicardial radiofrequency (RF) ablation procedure for NVAF and SPN resection. Our modified VATS-assisted ablation has improved the success rate by increasing the number of ablation lines and allowing left pulmonary surgery. In this study, we aim to describe this novel therapy, evaluate its feasibility and assess its preliminary safety and efficacy. MATERIALS AND METHODS Patient selection From March 2014 to January 2016, 16 patients diagnosed with left SPN and NVAF underwent this procedure. The study protocol was approved by the institutional review board, and informed consent was received from all patients. All patients were diagnosed with SPN by chest computed tomography (CT). Contrast-enhanced CT was performed for evaluating lymph nodes and distant metastases. Transthoracic echocardiography was routinely performed to evaluate cardiac structure and function. Patients with left SPN requiring an operation were considered appropriate candidates for this procedure. Surgical indication was determined according to the 2013 American College of Chest Physicians guidelines for SPN . Inclusion criteria included SPNs ≤3 cm in diameter requiring operation and without distant metastases confirmed by preoperative evaluation. The relative contraindications were previous cardiac or lung surgery, left atrial (LA) diameter >70 mm or moderate-to-severe valvular heart disease. The absolute contraindication was lung cancer with distant metastases. Standard preoperative evaluation was performed to exclude surgical contraindications. Surgical technique Surgery was performed under general anaesthesia with double-lumen endotracheal intubation. Modified epicardial AF ablation has been described previously . Transoesophageal echocardiography was performed routinely to exclude the existence of an LA thrombus. Right lateral decubitus position was adopted during the operation. Three ports were introduced around the subscapular angle line of the left chest wall. The camera port (10 mm) was introduced in the eighth intercostal space at the subscapular angle line. Two other working ports were introduced 30 mm anterior to the subscapular angle line in the sixth intercostal space and 10 mm posterior to the subscapular angle line in the seventh intercostal space (Fig. 1A). The surgical field was adequately exposed after isolating the left inferior pulmonary ligament and the pericardial suspension. Three circular and 3 linear lesions on the left atrium were achieved during the ablation. Bilateral pulmonary vein isolation was achieved by bipolar RF ablation with the AtriCure Isolator Synergy ablation clamp (AtriCure, Inc., Ohio, USA). The third circular lesion connecting the right and left pulmonary vein ablation rings was also made by bipolar RF clamp after exposing the dome of the left atrium (Fig. 1B). The effect of electrical isolation on all pulmonary veins was tested by an AtriCure Synergy ablation pen (AtriCure Inc.). Three linear lesions were performed with the ablation pen on the left atrium: the first between the left pulmonary vein and the incision of the LA appendage (LAA), the second between the 2 inferior pulmonary veins and the third from the right pulmonary vein to the aortic root. A sketch map of the 3 circular and 3 linear ablation lesions on the left atrium is illustrated (Fig. 1C). LAA was resected by Endo GIATM (Covidien, Missouri, USA) (Fig. 1D). The ablation of the epicardial ganglionic plexus was achieved by the ablation pen with the marshall ligament receiving targeted ablation. If a patient failed to restore sinus rhythm (SR) following ablation, cardioversion was immediately performed. Pulmonary surgery was performed after the ablation with a surgical approach appropriate to the intraoperative pathology (Fig. 1E). Figure 1: View largeDownload slide (A) All procedures were performed through 3 ports on the left chest wall. (B) Bilateral pulmonary vein isolation and a circular lesion connecting the right and left pulmonary vein ablation rings were made by bipolar radiofrequency clamp. (C) A sketch map of 3 circular and 3 linear ablation lesions on left atrium. (D) Resection of left atrial appendage with a stapler. (E) Solitary pulmonary nodule procedure following atrial fibrillation ablation. Figure 1: View largeDownload slide (A) All procedures were performed through 3 ports on the left chest wall. (B) Bilateral pulmonary vein isolation and a circular lesion connecting the right and left pulmonary vein ablation rings were made by bipolar radiofrequency clamp. (C) A sketch map of 3 circular and 3 linear ablation lesions on left atrium. (D) Resection of left atrial appendage with a stapler. (E) Solitary pulmonary nodule procedure following atrial fibrillation ablation. Postoperative management and follow-up The CHA2DS2-VAS score was applied in guiding the use of anticoagulants and can be explained as follows: congestive heart failure/left ventricular ejection fraction ≤ 40%, 1 point; hypertension: 1 point, age ≥75 years: 2 points, diabetes: 1 point, stroke/transient cerebral ischaemia: 2 points, age 65–74 years: 1 point and sex category (female): 1 point. Postoperative anticoagulation with warfarin or aspirin was administered for patients with a CHA2DS2-VAS score ≥2 during the 3-month blanking period. Anticoagulant drugs were discontinued if SR was present after the blanking period. Aspirin at 100 mg/day was continued if AF recurrence occurred. Amiodarone at 200 mg/day was also administered during the blanking period and tapered off in the presence of stable SR. Postoperative follow-up was conducted 3, 6 and 12 months following discharge and annually thereafter. Baseline characteristics, in-hospital outcomes and follow-up data were collected from inpatient and outpatient records. In addition to outpatient visits, telephone calls and questionnaires were also used for follow-up. Transthoracic echocardiography and 24-h Holter monitoring were performed on all patients in the outpatient clinic at each follow-up visit. AF was considered recurrent if confirmed by 24-h Holter monitoring or electrocardiogram with AF lasting more than 30 s. Chest CT was performed for patients with benign tumour or carcinoma at the 3rd and 6th postoperative months. Patients with malignant tumours were offered radiotherapy or chemotherapy according to pathological typing and tumour–node–metastasis (TNM) staging and received chest CT 2, 6 and 12 months postoperatively and annually thereafter. Statistical analysis Qualitative variables were expressed as numbers and percentages, and quantitative variables were expressed as mean ± standard deviation. Data analysis was performed with Statistical Package for Social Systems 12.0 (SPSS, Inc., Chicago, IL, USA). RESULTS Procedural success occurred in 100% of patients. There were no severe complications or postoperative mortality. Patient characteristics and operative outcomes are detailed in Table 1. Of the 16 included patients, 13 received lobectomy and 3 received wedge resection. There was no conversion to sternotomy or thoracotomy. Intraoperative cardioversion was performed in 4 patients. Mean bleeding volume was 150 ml, and no blood product transfusions occurred during hospitalization. The mean operative time was 203.1 ± 15.6 (range 177–224) min with an average hospitalization length of 9.1 ± 1.4 (range 7–11) days. No obvious abnormalities were detected during postoperative review by thoracic ultrasound and chest CT. The postoperative pathological typing was consistent with intraoperative frozen pathology and demonstrated 12 cases of lung adenocarcinoma, 1 squamous cell carcinoma, 1 inflammatory pseudotumour and 2 hamartoma. TNM staging is listed in Table 1. Table 1 Patient characteristics Patient number Age (years) Gender CHA2DS2- VAS score AF duration (years) AF type LAD (mm) Nodule site Pulmonary procedure Pathological type TNM stage Procedure time (min) Follow-up (months) 1 66 Male 2 4 Paroxysmal 43 Left upper lobe Lobectomy Adenocarcinoma T1bN0M0 212 32 2 53 Female 4 13 Persistent 46 Left lower lobe Lobectomy Adenocarcinoma T1aN0M0 202 28 3 59 Female 1 5 Paroxysmal 39 Left upper lobe Lobectomy Adenocarcinoma T1aN0M0 214 26 4 61 Male 2 11 Persistent 39 Left upper lobe Lobectomy Adenocarcinoma T1aN0M0 196 23 5 63 Female 2 6 Paroxysmal 42 Left lower lobe Lobectomy Adenocarcinoma TisN0M0 209 23 6 46 Male 1 4 Paroxysmal 38 Left lower lobe Lobectomy Adenocarcinoma T1aN0M0 206 22 7 56 Female 2 3 Paroxysmal 41 Left upper lobe Lobectomy Adenocarcinoma T1aN0M0 223 19 8 67 Female 3 15 Persistent 47 Left lower lobe Wedge resection Inflammatory pseudotumour 177 19 9 72 Male 2 3 Paroxysmal 44 Left lower lobe Lobectomy Adenocarcinoma T1bN1M0 199 18 10 61 Female 2 5 Paroxysmal 42 Left lower lobe Lobectomy Adenocarcinoma TisN0M0 213 16 11 57 Female 2 7 Paroxysmal 41 Left upper lobe Lobectomy Adenocarcinoma T1bN0M0 204 15 12 76 Male 5 2 Paroxysmal 48 Left upper lobe Wedge resection Hamartoma 168 14 13 76 Female 5 8 Persistent 41 Left lower lobe Lobectomy Adenocarcinoma T1aN0M0 224 14 14 38 Female 1 2 Paroxysmal 46 Left lower lobe Lobectomy Squamous cell carcinoma T1aN0M0 213 12 15 75 Male 4 12 Persistent 39 Left lower lobe Wedge resection Hamartoma 183 10 16 77 Male 4 9 Persistent 49 Left upper lobe Lobectomy Adenocarcinoma T1bN1M0 206 8 Patient number Age (years) Gender CHA2DS2- VAS score AF duration (years) AF type LAD (mm) Nodule site Pulmonary procedure Pathological type TNM stage Procedure time (min) Follow-up (months) 1 66 Male 2 4 Paroxysmal 43 Left upper lobe Lobectomy Adenocarcinoma T1bN0M0 212 32 2 53 Female 4 13 Persistent 46 Left lower lobe Lobectomy Adenocarcinoma T1aN0M0 202 28 3 59 Female 1 5 Paroxysmal 39 Left upper lobe Lobectomy Adenocarcinoma T1aN0M0 214 26 4 61 Male 2 11 Persistent 39 Left upper lobe Lobectomy Adenocarcinoma T1aN0M0 196 23 5 63 Female 2 6 Paroxysmal 42 Left lower lobe Lobectomy Adenocarcinoma TisN0M0 209 23 6 46 Male 1 4 Paroxysmal 38 Left lower lobe Lobectomy Adenocarcinoma T1aN0M0 206 22 7 56 Female 2 3 Paroxysmal 41 Left upper lobe Lobectomy Adenocarcinoma T1aN0M0 223 19 8 67 Female 3 15 Persistent 47 Left lower lobe Wedge resection Inflammatory pseudotumour 177 19 9 72 Male 2 3 Paroxysmal 44 Left lower lobe Lobectomy Adenocarcinoma T1bN1M0 199 18 10 61 Female 2 5 Paroxysmal 42 Left lower lobe Lobectomy Adenocarcinoma TisN0M0 213 16 11 57 Female 2 7 Paroxysmal 41 Left upper lobe Lobectomy Adenocarcinoma T1bN0M0 204 15 12 76 Male 5 2 Paroxysmal 48 Left upper lobe Wedge resection Hamartoma 168 14 13 76 Female 5 8 Persistent 41 Left lower lobe Lobectomy Adenocarcinoma T1aN0M0 224 14 14 38 Female 1 2 Paroxysmal 46 Left lower lobe Lobectomy Squamous cell carcinoma T1aN0M0 213 12 15 75 Male 4 12 Persistent 39 Left lower lobe Wedge resection Hamartoma 183 10 16 77 Male 4 9 Persistent 49 Left upper lobe Lobectomy Adenocarcinoma T1bN1M0 206 8 CHA2DS2-VAS score: congestive heart failure/left ventricular ejection fraction ≤40%: 1 point, hypertension: 1 point, age ≥75 years: 2 points, diabetes: 1 point, stroke/transient cerebral ischaemia: 2 points, age 65–74 years: 1 point, sex category (female): 1 point. AF: atrial fibrillation; CHF: congestive heart failure; LAD: left atrial dimension; TNM: tumour–node–metastasis. The mean follow-up duration was 18.7 ± 6.7 (range 8–32) months. At discharge, 15 of 16 patients were free from AF according to 24-h Holter monitoring and symptom resolution. Only 1 patient had recurrence of AF 6 months postoperatively. No additional recurrence of AF or thromboembolic events was detected during subsequent follow-up. There was also no mortality during follow-up. One patient received chemotherapy, and no patients received radiotherapy. No pulmonary vein stenosis or thrombosis was observed by echocardiography or chest CT at the 3rd postoperative month. DISCUSSION In China, pulmonary nodules are increasingly diagnosed with routine physical examination and high-definition CT. Pulmonary wedge resection via VATS is the most effective diagnostic method for SPN . If intraoperative tumour biopsy suggests malignancy, segmentectomy or lobectomy will be performed. Previous studies have demonstrated the advantages of the VATS approach for managing SPN over traditional thoracotomy . Traditionally, patients with SPN and AF had to receive sequential operations or additional medical management for arrhythmia. NVAF is the most common form of cardiac arrhythmia and is known to increase cardiovascular complications, including stroke, heart failure and all-cause mortality . The rate of successful SR restoration is limited with medical therapy, which requires lifelong medication for stroke prophylaxis and rate/rhythm control. With the advent of several modified VATS ablation procedures, procedural success rates have increased, and complication rates have fallen. Therefore, thoracoscopic-assisted ablation may be a promising treatment modality for NVAF, particularly for patients undergoing surgical SPN resection. Our team had described previously a novel modified thoracoscopic-assisted ablation procedure characterized by the left thoracic approach with modified ablation on the left atrium. This novel approach utilized 3 ports on the left chest wall around the left subscapular line, which made it possible to achieve bilateral pulmonary vein isolation, LA ablation, resection of the LAA and ganglion plexus ablation . Using this approach, lobectomy may also be performed with relative ease. Left lower lobectomy was completed following routine operative techniques, beginning with resection of the inferior pulmonary ligament, followed by inferior pulmonary vein, artery and finally bronchus. Compared with the routine upper lobectomy position, our approach employs a relatively lower position. To minimize the influence of the lower position, we performed pulmonary vein dissection by stapler through the assistant working port or camera port, followed by pulmonary artery and bronchi amputation. Thoracoscopic-assisted surgery and ablation was previously performed separately but can now be accomplished concomitantly using our novel approach. During follow-up, postoperative recovery was uneventful with SR maintenance occurring in all patients receiving ablation. As a result, there was reduced risk of complications associated with postoperative AF, such as haemodynamic instability, thromboembolic events or acute heart failure. SR restoration for NVAF patients may confer long-term benefits by maintaining cardiac function and preventing stroke. We have previously reported a success rate of 86.9% in SR restoration, effective symptomatic control and no postoperative stroke using this modified epicardial RF ablation procedure at 2-year follow-up . Postoperative SR restoration and LAA resection may be effective for stroke prevention. Furthermore, the LA function of patients achieving SR maintenance was also improved following our modified AF ablation procedure . Our experience demonstrated that the concomitant VATS-assisted NVAF ablation with SPN resection is feasible and may be safe and efficacious. To our knowledge, our procedure is a novel technique that differs from most video-assisted AF ablation procedures, which are normally performed through the bilateral approach . If ablation is performed via the bilateral approach, lung surgery may be performed on both sides. Further research is needed to assess the outcomes of this concomitant procedure. ACKNOWLEDGEMENTS We would like to thank Saie Shen, Yuan Sun, Yin Cai, Mingsong Wang, Huihua Chen and Yu Su for their excellent experimental and clinical support. Funding This work was supported by National Natural Science Foundation of China (grant numbers: 81570290, 81600264) and Science and Technology Commission of Shanghai Municipality (grant number: 15411952600). Conflict of interest: none declared. REFERENCES 1 Ost D, Fein AM, Feinsilver SH. Clinical practice. The solitary pulmonary nodule. 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Interactive CardioVascular and Thoracic Surgery – Oxford University Press
Published: Mar 1, 2018
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