Echocardiographic criteria to detect unicuspid aortic valve morphology

Echocardiographic criteria to detect unicuspid aortic valve morphology Abstract Aims Unicuspid aortic valve (UAV) is a rare congenital malformation associated with severe aortic stenosis or regurgitation. This study aimed to systematically determine echocardiographic criteria to identify UAV. Methods and results All patients underwent a preoperative baseline examination, including echocardiography. A total of 69 patients with intraoperatively confirmed UAV underwent an aortic valve repair procedure between August 2001 and May 2011. To compare the findings of UAV cases with those of other valve morphologies, we examined 99 consecutive patients with a bicuspid aortic valve (BAV) and 103 consecutive patients with a tricuspid aortic valve (TAV) undergoing isolated aortic valve surgery before May 2016. The mean age of the 271 patients was 44.2 ± 12.8 years; 85% were male, with a mean body mass index of 26.2 ± 4.0 kg/m2. Patients with UAV were younger and had fewer co-morbidities than patients with BAV or TAV, respectively. The major criteria for the echocardiographic diagnosis of UAV were defined based on our preoperative examination as follows: (i) single commissural attachment zone, (ii) rounded, leaflet-free edge on the opposite side of the commissural attachment zone, (iii) eccentric valvular orifice during systole, and (iv) patient age <20 years and mean transvalvular gradient >15 mmHg. The minor criteria were defined as an associated thoracic aortopathy and age <40 years. Three out of the four major criteria or two out of the four major criteria and one minor criterion were met in all patients with UAV and in none of the patients with BAV or TAV. Associated 95% confidence intervals were calculated for each estimate of sensitivity (94.7–100%) and specificity (98.1–100%), indicating that an adequate number of patients were included in each of the three groups. Conclusion The proposed echocardiographic score appears to be a specific and sensitive method to distinguish UAV from BAV and TAV. echocardiography, unicuspid aortic valve, preoperative assessment, echocardiographic score Introduction Unicuspid aortic valve (UAV) is a rare congenital cardiac valvular anomaly with an estimated prevalence of 0.02% in adults who are undergoing transthoracic echocardiography (TTE), frequently causing valve dysfunction, usually in the third to fifth decade of life.1,2 UAV is described as one of the main causes of congenital aortic valve stenosis and regurgitation in infants, children, and young adults.2,3 UAV is often misdiagnosed as the more prevalent bicuspid aortic valve (BAV), due to similar symptoms and characteristics during cardiac imaging.2 The diagnosis was previously based on autopsy or intraoperative inspection of the valve; the advance of cardiac imaging modalities, however, may allow diagnosis of UAV by TTE and transoesophageal echocardiographic (TOE) evaluation.4 Correct diagnosis can sometimes be complicated by the presence of calcification, and the number of commissures at the level of the sinotubular junction is critical in distinguishing between UAV and BAV.5 Precise information regarding valve morphology is crucial for aortic valve intervention, reconstruction, or replacement.6,7 However, the echocardiographic features to detect UAV and distinguish it from other morphologies are not well defined. Consequently, despite its important prognostic implications for patients, this disorder is mostly missed. This study aims to systematically determine the echocardiographic criteria to diagnose UAV morphology. Methods From August 2001 to May 2011, 69 patients underwent an aortic valve repair procedure for severe aortic regurgitation or stenosis and suspected UAV. The valve morphology was confirmed intraoperatively by one experienced surgeon (H.J.S.). To compare our echocardiographic findings with other valve morphologies, we investigated 99 consecutive patients with a BAV and 103 consecutive patients with a tricuspid aortic valve (TAV) who underwent isolated aortic valve surgery and were discussed by the Homburg Heart Team from May 2016 backwards. Patients with BAV were further scaled by the classification of Angelini.8 Based on our statistical analysis, a sufficient number of BAV and TAV patients was included to allow a statistically valid differentiation from patients with UAV. Echocardiographic assessment All patients underwent preoperative baseline examination that included an echocardiographic examination. TTE and TOE were performed on a Vivid 7 and E9 (General Electric, Frankfurt, Germany) machine by experienced echocardiographers. If the TTE image modality (parasternal short-axis) was adequate, no further TOE assessment was prompted. The analysis of the echocardiography was performed retrospectively by two experienced investigators who were blinded to the result of the intraoperative valve inspection and clinical parameters. Special attention was paid on known anatomic landmarks for the presence of a UVA such as a single commissural zone of attachment, a rounded leaflet-free edge on the opposite side of the commissural attachment zone and an eccentric valvular orifice (Figure 1).5 Figure 1 View largeDownload slide schematic illustration of an unicuspid aortic valve morphology, assessed from a 2D transthoracic parasternal short-axis view. Figure 1 View largeDownload slide schematic illustration of an unicuspid aortic valve morphology, assessed from a 2D transthoracic parasternal short-axis view. Statistical analysis Data are presented as mean ± standard deviation unless otherwise specified. Statistical comparisons between groups were performed using the Pearson’s χ2 test for categorical variables and the paired and unpaired t-test, the Wilcoxon rank-sum test, or the one-way-ANOVA for continuous variables wherever appropriate. Significance tests were two-tailed, with P-value of <0.05 considered significant. The clinical diagnosis of UAV using each of the defined criteria was used to determine the sensitivity and the specificity. The associated 95% confidence intervals were calculated for each of the estimates of sensitivity (94.7–100%) and specificity (98.1–100%), indicating an adequate number of patients had been included in each of the three groups to detect intergroup differences.9 Based on the sensitivity and the specificity of each individual criterion, the classification in the major and the minor criteria was determined. All statistical analyses were calculated using SPSS statistical software (version 20.0, SPSS Inc., Chicago, IL, USA). Results Table 1 depicts baseline patient characteristics. Mean patient age was 44.2 ± 12.8 years; 85% were male, with a mean body mass index of 26.2 ± 4.0 kg/m2 and a body surface area of 1.99 ± 0.26 cm/m2. Patients with UAV were younger, smaller and had been prescribed less medication than patients with BAV and TAV (P < 0.001 for all). None of the patients was diabetic. Predominant aortic stenosis was present in 18 (7%) patients, aortic regurgitation in 239 (88%) patients, and combined aortic valve disease in 14 (5%) patients. Table 1 Baseline characteristics Number of patients All patients UAV BAV TAV P-value n = 271 n = 69 n = 99 n = 103 Age (years), mean ± SD 44.2 ± 12.8 29.0 ± 13.0 43.3 ± 12.2 60.4 ± 13.2 <0.001 Male, n (%) 229 (85) 61 (88) 94 (95) 74 (72) <0.001 BMI (kg/m2), mean ± SD 26.2 ± 4.0 25.2 ± 4.5 27.4 ± 3.6 26.1 ± 3.8 0.028 BSA after Mosteller (m2), mean ± SD 1.99 ± 0.26 1.92 ± 0.32 2.09 ± 0.19 1.98 ± 0.19 <0.001 Coronary artery disease, n (%) 22 (8) 1 (2) 1 (1) 20 (19) <0.001 Hypertension, n (%) 168 (62) 29 (42) 51 (51) 88 (85) <0.001 Hypercholesterolemia, n (%) 71 (26) 18 (26) 8 (8) 45 (44) <0.001 Type 2 diabetes, n (%) 27 (10) 0 (0) 19 (40) 8 (8) 0.016 Cystatin GFR >60 mL/min/1.73 m2, n (%) 258 (95) 69 (100) 99 (100) 90 (87) 0.441 Number of all prescribed drugs, mean ± SD 0.9 ± 0.8 0.5 ± 0.6 1.0 ± 0.7 1.3 ± 1.1 <0.001 Number of patients All patients UAV BAV TAV P-value n = 271 n = 69 n = 99 n = 103 Age (years), mean ± SD 44.2 ± 12.8 29.0 ± 13.0 43.3 ± 12.2 60.4 ± 13.2 <0.001 Male, n (%) 229 (85) 61 (88) 94 (95) 74 (72) <0.001 BMI (kg/m2), mean ± SD 26.2 ± 4.0 25.2 ± 4.5 27.4 ± 3.6 26.1 ± 3.8 0.028 BSA after Mosteller (m2), mean ± SD 1.99 ± 0.26 1.92 ± 0.32 2.09 ± 0.19 1.98 ± 0.19 <0.001 Coronary artery disease, n (%) 22 (8) 1 (2) 1 (1) 20 (19) <0.001 Hypertension, n (%) 168 (62) 29 (42) 51 (51) 88 (85) <0.001 Hypercholesterolemia, n (%) 71 (26) 18 (26) 8 (8) 45 (44) <0.001 Type 2 diabetes, n (%) 27 (10) 0 (0) 19 (40) 8 (8) 0.016 Cystatin GFR >60 mL/min/1.73 m2, n (%) 258 (95) 69 (100) 99 (100) 90 (87) 0.441 Number of all prescribed drugs, mean ± SD 0.9 ± 0.8 0.5 ± 0.6 1.0 ± 0.7 1.3 ± 1.1 <0.001 BAV, bicuspid aortic valve; BMI, body mass index; BSA, body surface area; SD: standard deviation; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Table 1 Baseline characteristics Number of patients All patients UAV BAV TAV P-value n = 271 n = 69 n = 99 n = 103 Age (years), mean ± SD 44.2 ± 12.8 29.0 ± 13.0 43.3 ± 12.2 60.4 ± 13.2 <0.001 Male, n (%) 229 (85) 61 (88) 94 (95) 74 (72) <0.001 BMI (kg/m2), mean ± SD 26.2 ± 4.0 25.2 ± 4.5 27.4 ± 3.6 26.1 ± 3.8 0.028 BSA after Mosteller (m2), mean ± SD 1.99 ± 0.26 1.92 ± 0.32 2.09 ± 0.19 1.98 ± 0.19 <0.001 Coronary artery disease, n (%) 22 (8) 1 (2) 1 (1) 20 (19) <0.001 Hypertension, n (%) 168 (62) 29 (42) 51 (51) 88 (85) <0.001 Hypercholesterolemia, n (%) 71 (26) 18 (26) 8 (8) 45 (44) <0.001 Type 2 diabetes, n (%) 27 (10) 0 (0) 19 (40) 8 (8) 0.016 Cystatin GFR >60 mL/min/1.73 m2, n (%) 258 (95) 69 (100) 99 (100) 90 (87) 0.441 Number of all prescribed drugs, mean ± SD 0.9 ± 0.8 0.5 ± 0.6 1.0 ± 0.7 1.3 ± 1.1 <0.001 Number of patients All patients UAV BAV TAV P-value n = 271 n = 69 n = 99 n = 103 Age (years), mean ± SD 44.2 ± 12.8 29.0 ± 13.0 43.3 ± 12.2 60.4 ± 13.2 <0.001 Male, n (%) 229 (85) 61 (88) 94 (95) 74 (72) <0.001 BMI (kg/m2), mean ± SD 26.2 ± 4.0 25.2 ± 4.5 27.4 ± 3.6 26.1 ± 3.8 0.028 BSA after Mosteller (m2), mean ± SD 1.99 ± 0.26 1.92 ± 0.32 2.09 ± 0.19 1.98 ± 0.19 <0.001 Coronary artery disease, n (%) 22 (8) 1 (2) 1 (1) 20 (19) <0.001 Hypertension, n (%) 168 (62) 29 (42) 51 (51) 88 (85) <0.001 Hypercholesterolemia, n (%) 71 (26) 18 (26) 8 (8) 45 (44) <0.001 Type 2 diabetes, n (%) 27 (10) 0 (0) 19 (40) 8 (8) 0.016 Cystatin GFR >60 mL/min/1.73 m2, n (%) 258 (95) 69 (100) 99 (100) 90 (87) 0.441 Number of all prescribed drugs, mean ± SD 0.9 ± 0.8 0.5 ± 0.6 1.0 ± 0.7 1.3 ± 1.1 <0.001 BAV, bicuspid aortic valve; BMI, body mass index; BSA, body surface area; SD: standard deviation; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Table 2 illustrates echocardiographic values for the left ventricle and the proximal part of the ascending aorta. Eight (12%) patients with UAV, 30 (30%) patients with BAV, and 25 (24%) patients with TAV had normal sized left ventricular geometry and a preserved ejection fraction > 55%. Patients suffering from UAV had a higher mean ejection fraction than those with BAV (−3 ± 7%, P = 0.047) and TAV (−6 ± 8%, P < 0.001). The sinus diameter (1.84 ± 0.31 cm/m2, P < 0.001) and the sinus-tubular junction (1.68 ± 0.36 cm/m2, P < 0.001) of the ascending aorta were more pronounced in patients with BAV than those with UAV and TAV. Six (6%) patients with a BAV had no raphe (type 0) and 93 (94%) patients had a single raphe [type 1: 76/93 (82%) L-R, 13/93 (14%) R-N, and 4/93 (4%) N-L).8 Table 2 Echocardiographic parameters for the left ventricle and the proximal part of the ascending aorta Echocardiographic value [value related to BSA (cm/m2)] UAV BAV TAV P-value n = 69, mean ± SD n = 99, mean ± SD n = 103, mean ± SD MDAA 1.76 ± 0.38 1.8 ± 0.38 2.05 ± 0.52 0.45 LVEDD 3.0 ± 0.7 2.9 ± 0.39 2.93 ± 0.65 0.536 LVESD 2.04 ± 0.49 2.04 ± 0.34 2.12 ± 0.58 0.453 Annulus diameter 1.29 ± 0.25 1.32 ± 0.2 1.29 ± 0.23 0.64 Sinus diameter 1.7 ± 0.34 1.84 ± 0.31 1.72 ± 0.34 <0.001 STJ diameter 1.6 ± 0.34 1.68 ± 0.36 1.57 ± 0.42 <0.001 Ejection fraction (%) 58 ± 13 55 ± 11 52 ± 13 0.018 Echocardiographic value [value related to BSA (cm/m2)] UAV BAV TAV P-value n = 69, mean ± SD n = 99, mean ± SD n = 103, mean ± SD MDAA 1.76 ± 0.38 1.8 ± 0.38 2.05 ± 0.52 0.45 LVEDD 3.0 ± 0.7 2.9 ± 0.39 2.93 ± 0.65 0.536 LVESD 2.04 ± 0.49 2.04 ± 0.34 2.12 ± 0.58 0.453 Annulus diameter 1.29 ± 0.25 1.32 ± 0.2 1.29 ± 0.23 0.64 Sinus diameter 1.7 ± 0.34 1.84 ± 0.31 1.72 ± 0.34 <0.001 STJ diameter 1.6 ± 0.34 1.68 ± 0.36 1.57 ± 0.42 <0.001 Ejection fraction (%) 58 ± 13 55 ± 11 52 ± 13 0.018 BAV, bicuspid aortic valve; BSA, body surface area; LVEDD, left ventricle end-diastolic diameter; LVESD, left ventricle end-systolic diameter; MDAA, mean diameter of the aorta ascending; SD, standard deviation; SJT, Sino-tubular junction; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Table 2 Echocardiographic parameters for the left ventricle and the proximal part of the ascending aorta Echocardiographic value [value related to BSA (cm/m2)] UAV BAV TAV P-value n = 69, mean ± SD n = 99, mean ± SD n = 103, mean ± SD MDAA 1.76 ± 0.38 1.8 ± 0.38 2.05 ± 0.52 0.45 LVEDD 3.0 ± 0.7 2.9 ± 0.39 2.93 ± 0.65 0.536 LVESD 2.04 ± 0.49 2.04 ± 0.34 2.12 ± 0.58 0.453 Annulus diameter 1.29 ± 0.25 1.32 ± 0.2 1.29 ± 0.23 0.64 Sinus diameter 1.7 ± 0.34 1.84 ± 0.31 1.72 ± 0.34 <0.001 STJ diameter 1.6 ± 0.34 1.68 ± 0.36 1.57 ± 0.42 <0.001 Ejection fraction (%) 58 ± 13 55 ± 11 52 ± 13 0.018 Echocardiographic value [value related to BSA (cm/m2)] UAV BAV TAV P-value n = 69, mean ± SD n = 99, mean ± SD n = 103, mean ± SD MDAA 1.76 ± 0.38 1.8 ± 0.38 2.05 ± 0.52 0.45 LVEDD 3.0 ± 0.7 2.9 ± 0.39 2.93 ± 0.65 0.536 LVESD 2.04 ± 0.49 2.04 ± 0.34 2.12 ± 0.58 0.453 Annulus diameter 1.29 ± 0.25 1.32 ± 0.2 1.29 ± 0.23 0.64 Sinus diameter 1.7 ± 0.34 1.84 ± 0.31 1.72 ± 0.34 <0.001 STJ diameter 1.6 ± 0.34 1.68 ± 0.36 1.57 ± 0.42 <0.001 Ejection fraction (%) 58 ± 13 55 ± 11 52 ± 13 0.018 BAV, bicuspid aortic valve; BSA, body surface area; LVEDD, left ventricle end-diastolic diameter; LVESD, left ventricle end-systolic diameter; MDAA, mean diameter of the aorta ascending; SD, standard deviation; SJT, Sino-tubular junction; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Based on anatomic landmarks from the literature,5 our echocardiographic findings and the Homburg Heart Team discussion, the following echocardiographic diagnostic criteria were defined as major criteria to detect a UAV: (i) single commissural zone of attachment, (ii) rounded leaflet-free edge on the opposite side of the commissural attachment zone, (iii) eccentric valvular orifice during systole, and (iv) age <20 years and delta mean pressure gradient (dPmean) >15 mmHg. Age <40 years and an associated thoracic aortopathy (e.g. dilatation and aortic coarctation) were defined as minor criteria. The four major criteria (single commissural zone of attachment; rounded, leaflet-free edge on the opposite side of the commissural attachment zone; eccentric valvular orifice during systole; and age <20 years and dPmean >15 mmHg) were met by 68 (99%) patients, 63 (91%) patients, 68 (99%) patients, and 13 (19%) patients with a UAV, respectively (Figure 2). None of the patients with TAV fulfilled any of the major criteria (Table 3). The minor criteria of age <40 years and having an associated thoracic aortopathy were met in 56 (81%) patients and 30 (44%) patients with UAV, respectively. In patients with BAV, an associated thoracic aortopathy [aortic dilatation in 48 (48%) patients] was numerally more present. However, this difference did not reach statistical significance (P = 0.382 for all) compared with patients with UAV (44%) and TAV (34%). All patients with UAV met three out of the four major criteria or two out of the four major criteria and one minor criterion. This was not true for any of the patients with BAV or TAV. Table 3 Echocardiographic criteria to differentiate aortic valve morphology Echocardiographic criteria UAV BAV TAV P-value n = 69, n (%) n = 99, n (%) n = 103, n (%) Single commissural zone of attachment 68 (99) 7 (7) 0 (0) <0.001 Rounded leaflet-free edge on the opposite side of the commissural attachment zone 63 (91) 0 (0) 0 (0) <0.001 Eccentric valvular orifice during systole 68 (99) 12 (12) 0 (0) <0.001 Age <20 years and dPmean >15 mmHg 13 (19) 1 (1) 0 (0) <0.001 Age <40 years 56 (81) 37 (37) 10 (10) <0.001 Associated thoracic aortopathy 30 (44) 48 (48) 35 (34) 0.382 Echocardiographic criteria UAV BAV TAV P-value n = 69, n (%) n = 99, n (%) n = 103, n (%) Single commissural zone of attachment 68 (99) 7 (7) 0 (0) <0.001 Rounded leaflet-free edge on the opposite side of the commissural attachment zone 63 (91) 0 (0) 0 (0) <0.001 Eccentric valvular orifice during systole 68 (99) 12 (12) 0 (0) <0.001 Age <20 years and dPmean >15 mmHg 13 (19) 1 (1) 0 (0) <0.001 Age <40 years 56 (81) 37 (37) 10 (10) <0.001 Associated thoracic aortopathy 30 (44) 48 (48) 35 (34) 0.382 BAV, bicuspid aortic valve; dPmean, delta mean pressure gradient; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Table 3 Echocardiographic criteria to differentiate aortic valve morphology Echocardiographic criteria UAV BAV TAV P-value n = 69, n (%) n = 99, n (%) n = 103, n (%) Single commissural zone of attachment 68 (99) 7 (7) 0 (0) <0.001 Rounded leaflet-free edge on the opposite side of the commissural attachment zone 63 (91) 0 (0) 0 (0) <0.001 Eccentric valvular orifice during systole 68 (99) 12 (12) 0 (0) <0.001 Age <20 years and dPmean >15 mmHg 13 (19) 1 (1) 0 (0) <0.001 Age <40 years 56 (81) 37 (37) 10 (10) <0.001 Associated thoracic aortopathy 30 (44) 48 (48) 35 (34) 0.382 Echocardiographic criteria UAV BAV TAV P-value n = 69, n (%) n = 99, n (%) n = 103, n (%) Single commissural zone of attachment 68 (99) 7 (7) 0 (0) <0.001 Rounded leaflet-free edge on the opposite side of the commissural attachment zone 63 (91) 0 (0) 0 (0) <0.001 Eccentric valvular orifice during systole 68 (99) 12 (12) 0 (0) <0.001 Age <20 years and dPmean >15 mmHg 13 (19) 1 (1) 0 (0) <0.001 Age <40 years 56 (81) 37 (37) 10 (10) <0.001 Associated thoracic aortopathy 30 (44) 48 (48) 35 (34) 0.382 BAV, bicuspid aortic valve; dPmean, delta mean pressure gradient; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Figure 2 View largeDownload slide echocardiographic findings of aortic valve morphology, assessed from a 2D transoesophageal short-axis view (30–60°). BAV, bicuspid aortic valve; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Figure 2 View largeDownload slide echocardiographic findings of aortic valve morphology, assessed from a 2D transoesophageal short-axis view (30–60°). BAV, bicuspid aortic valve; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Based on the individual analyses of the two experienced echocardiographers, 67 of 69 (97%) patients with UAV, 96 of 99 (97%) patients with BAV, and 102 of 103 (99%) patients with TAV were classified identically. In the six unequally evaluated morphologies, a decision was made by the Homburg Heart team. Discussion The increasing number of treatment options for aortic valve disease requires a precise definition of the valve pathology in order to choose the best treatment. Currently, the best morphological information is provided by echocardiography. UAV is a rare pathology, which may present as congenital stenosis, as regurgitation, or in conjunction with ascending aortic aneurysm. Unicuspid valves may be subject to repair, especially in juvenile patients or young adults.6 Therefore, the exact morphological diagnosis will be of marked clinical relevance. Congenital UAV is a rare pathology causing aortic valve disease in young adolescent and adults. However, this incidence is probably underestimated.10,11 Since many UAV are misdiagnosed as BAV by surgeons.10 When relying on echocardiographic studies the prevalence is probably even more underestimated because there are no generally accepted echocardiographic criteria which allow a precise differentiation between UAV, BAV, and TAV. Such a differentiation, however, is of increasing clinical importance. Earlier, when surgical aortic valve replacement was the only therapeutic option, a precise preoperatively anatomic characterization was of limited importance as the valve was excised irrespective of anatomical features. Currently, surgical aortic valve repair and transcatheter interventions have become clinically accepted modalities.7,12 Transcatheter interventions yield the most predictable results in the presence of TAV anatomy; its use in BAV is possible but controversially discussed,13,14 and there is no data on UAV. Considering the anatomical features and characterization of patients with UAV, even in the dynamic progress of transcatheter aortic valve implantation,15 till date or the near future, the interventional approach may only be a ‘bail out’ option (e.g. in case of contra indication for surgery) and not recommended on a routine basis.12 The detailed anatomic characterization is even more important if valve reconstruction is considered. Both BAV and UAV require very specific and individualized repair approaches.6,7,16 In the view of the anatomic variability and in order to facilitate echocardiographic analysis, we decided to create an echocardiographic score that allows the identification of UAV from BAV and TAV in a specific and sensitive way. A TAV is anatomically characterized by three commissures and three cusps with complete separation of cusp tissue.17 The BAV has two commissures of normal height which may vary in their circumferential orientation. In addition, there is very often a third, rudimentary commissure, which is of abnormally low height. The cusps are fused to a variable degree in the area of the rudimentary commissure, producing a raphe.18 UAVs occurs in acommissural (very rare) or unicommissural variants.5 Herein, we focus on the more common, the unicommissural valve. This valve pathology is characterized by one commissure of normal height, in our clinical experience almost always the one between left and non-coronary cusps. The two other commissures are most often hypoplastic, i.e. of subnormal height. There is a variable degree of cusp fusion adjacent to the hypoplastic commissures, thus two raphes may be seen.5 Therefore, the presence of two raphes is highly suggestive of unicuspid rather than bicuspid anatomy.18 These aspects may be visualized to different extent. A TAV will show on a short-axis view three commissures of similar height, which usually have an orientation of 120°. In systole opening of the cusps results in an orifice resembling a circle and complete in the area of the commissure. In BAV the height of the two functional commissures and the one rudimentary commissure may be difficult to define in the short-axis view. The fusion of cusp tissue adjacent to the rudimentary commissure is visible by incomplete opening in systole. Thus, in systole the cusps in the area of functioning commissures open completely resulting in a ‘fish mouth’ orifice. Extrapolating the anatomical characteristics of UAV, in echocardiography only one functional commissure of normal height would be expected in the short-axis view. This difference in commissural height may be suggested in the short-axis view: often a SAX will derive an image with the normal commissure open while the two rudimentary commissures are barely visible. This phenomenon can be difficult to quantify precisely with standard 2D imaging. The most striking finding is incomplete opening of the cusp tissue adjacent to the rudimentary cusps in a short-axis view, resulting in an eccentric circular orifice. This characteristic orifice in systole has also been observed by others.1 We have found the size of the opening area to vary, depending on the degree of stenosis. Since the valve assumes a funnel-shaped form in systole also this feature is best defined by 3D echocardiography. With appropriate imaging techniques correlates of these anatomic features of the UAV can be detected, which was the basis for our echocardiographic criteria. Based on our preoperative echo findings and the intraoperative visual examination above mentioned criteria were defined. Our study confirms that UAV can be identified by preoperative echocardiography using several criteria. The apparently most important are: single commissural zone of attachment, rounded leaflet-free edge on opposite side of the commissural attachment zone, and eccentric valvular orifice during systole. Furthermore, age <20 years and dPmean >15 mmHg were defined as major criteria. Age <40 years and an associated thoracic aortopathy (e.g. dilatation and aortic coarctation) were considered as minor criteria. In our experience, these echocardiographic findings are a specific and sensitive method to differentiate UAV both from BAV and TAV; this was confirmed by this study. Limitations Due to the study design, a potential selection bias contributing to the outcome of the results cannot be fully excluded. The echocardiographic assessment was performed by multiple operators; however, the retrospective analyses were conducted by two experienced operators from the Homburg Heart Team. Due to its 3D structure, 3D echocardiography might have helped to better differentiate the aortic valve morphology.19 BAV were scaled by the classification of Angelini8 and not by the classification Sievers and Schmidtke.18 Conclusion This echocardiographic score is a specific and sensitive method to differentiate UAV from BAV and TAV and might provide important benefits in the preoperative assessment of patients undergoing aortic valve procedures. Conflict of interest: None declared. Funding This retrospective analysis is an investigator initiated study without any funding. References 1 Novaro GM , Mishra M , Griffin BP. Incidence and echocardiographic features of congenital unicuspid aortic valve in an adult population . J Heart Valve Dis 2003 ; 12 : 674 – 8 . Google Scholar PubMed 2 Roberts WC , Ko JM. Frequency by decades of unicuspid, bicuspid, and tricuspid aortic valves in adults having isolated aortic valve replacement for aortic stenosis, with or without associated aortic regurgitation . Circulation 2005 ; 111 : 920 – 5 . http://dx.doi.org/10.1161/01.CIR.0000155623.48408.C5 Google Scholar CrossRef Search ADS PubMed 3 Miyamoto T , Sinzobahamvya N , Wetter J , Kallenberg R , Brecher AM , Asfour B et al. Twenty years experience of surgical aortic valvotomy for critical aortic stenosis in early infancy . Eur J Cardiothorac Surg 2006 ; 30 : 35 – 40 . Google Scholar CrossRef Search ADS PubMed 4 Evangelista A , Flachskampf FA , Erbel R , Antonini-Canterin F , Vlachopoulos C , Rocchi G et al. Echocardiography in aortic diseases: EAE recommendations for clinical practice . Eur J Echocardiogr 2010 ; 11 : 645 – 58 . Google Scholar CrossRef Search ADS PubMed 5 Anderson RH. Understanding the structure of the unicuspid and unicommissural aortic valve . J Heart Valve Dis 2003 ; 12 : 670 – 3 . Google Scholar PubMed 6 Aicher D , Bewarder M , Kindermann M , Abdul-Khalique H , Schäfers HJ. Aortic valve function after bicuspidization of the unicuspid aortic valve . Ann Thorac Surg 2013 ; 95 : 1545 – 50 . Google Scholar CrossRef Search ADS PubMed 7 Schäfers HJ , Aicher D , Riodionycheva S , Lindinger A , Radle-Hurst T , Langer F et al. Bicuspidization of the unicuspid aortic valve: a new reconstructive approach . Ann Thorac Surg 2008 ; 85 : 2012 – 8 . Google Scholar CrossRef Search ADS PubMed 8 Angelini A , Ho SY , Anderson RH , Devine WA , Zuberbuhler JR , Becker AE et al. The morphology of the normal aortic valve as compared with the aortic valve having two leaflets . J Thorac Cardiovasc Surg 1989 ; 98 : 362 – 7 . Google Scholar PubMed 9 Wilson EB. Probable Inference, the Law of Succession, and Statistical Inference . J Am Stat Assoc 1927 ; 22 : 209 – 12 . http://dx.doi.org/10.1080/01621459.1927.10502953 Google Scholar CrossRef Search ADS 10 Roberts WC. The congenitally bicuspid aortic valve. A study of 85 autopsy cases . Am J Cardiol 1970 ; 26 : 72 – 83 . Google Scholar CrossRef Search ADS PubMed 11 Mookadam F , Thota VR , Garcia-Lopez AM , Emani UR , Alharthi MS , Zamorano J et al. Unicuspid aortic valve in adults: a systematic review . J Heart Valve Dis 2010 ; 19 : 79 – 85 . Google Scholar PubMed 12 Baumgartner H , Falk V , Bax JJ , De Bonis M , Hamm C , Holm PJ et al. 2017 ESC/EACTS Guidelines for the management of valvular heart disease . Eur Heart J 2017 ; 38 : 2739 – 91 . Google Scholar CrossRef Search ADS PubMed 13 Hakeem A , Cilingiroglu M. Outcomes of TAVR in bicuspid aortic valve stenosis . J Am Coll Cardiol 2017 ; 70 : 1684 – 5 . http://dx.doi.org/10.1016/j.jacc.2017.06.071 Google Scholar CrossRef Search ADS PubMed 14 Yoon SH , Bleiziffer S , De Backer O , Delgado V , Arai T , Ziegelmueller J et al. Outcomes in transcatheter aortic valve replacement for bicuspid versus tricuspid aortic valve stenosis . J Am Coll Cardiol 2017 ; 69 : 2579 – 89 . http://dx.doi.org/10.1016/j.jacc.2017.03.017 Google Scholar CrossRef Search ADS PubMed 15 Kim WK , Hamm CW. The future of TAVI . Eur Heart J 2017 ; 38 : 2704 – 7 . http://dx.doi.org/10.1093/eurheartj/ehx474 Google Scholar CrossRef Search ADS PubMed 16 Schäfers HJ , Aicher D , Langer F , Lausberg HF. Preservation of the bicuspid aortic valve . Ann Thorac Surg 2007 ; 83 : S740 – 5 . Google Scholar CrossRef Search ADS PubMed 17 Loukas M , Bilinsky E , Bilinsky S , Blaak C , Tubbs RS , Anderson RH. The anatomy of the aortic root . Clin Anat 2014 ; 27 : 748 – 56 . Google Scholar CrossRef Search ADS PubMed 18 Sievers HH , Schmidtke C. A classification system for the bicuspid aortic valve from 304 surgical specimens . J Thorac Cardiovasc Surg 2007 ; 133 : 1226 – 33 . http://dx.doi.org/10.1016/j.jtcvs.2007.01.039 Google Scholar CrossRef Search ADS PubMed 19 Shiota T. Role of modern 3D echocardiography in valvular heart disease . Korean J Intern Med 2014 ; 29 : 685 – 702 . http://dx.doi.org/10.3904/kjim.2014.29.6.685 Google Scholar CrossRef Search ADS PubMed Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. 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Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.
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Abstract

Abstract Aims Unicuspid aortic valve (UAV) is a rare congenital malformation associated with severe aortic stenosis or regurgitation. This study aimed to systematically determine echocardiographic criteria to identify UAV. Methods and results All patients underwent a preoperative baseline examination, including echocardiography. A total of 69 patients with intraoperatively confirmed UAV underwent an aortic valve repair procedure between August 2001 and May 2011. To compare the findings of UAV cases with those of other valve morphologies, we examined 99 consecutive patients with a bicuspid aortic valve (BAV) and 103 consecutive patients with a tricuspid aortic valve (TAV) undergoing isolated aortic valve surgery before May 2016. The mean age of the 271 patients was 44.2 ± 12.8 years; 85% were male, with a mean body mass index of 26.2 ± 4.0 kg/m2. Patients with UAV were younger and had fewer co-morbidities than patients with BAV or TAV, respectively. The major criteria for the echocardiographic diagnosis of UAV were defined based on our preoperative examination as follows: (i) single commissural attachment zone, (ii) rounded, leaflet-free edge on the opposite side of the commissural attachment zone, (iii) eccentric valvular orifice during systole, and (iv) patient age <20 years and mean transvalvular gradient >15 mmHg. The minor criteria were defined as an associated thoracic aortopathy and age <40 years. Three out of the four major criteria or two out of the four major criteria and one minor criterion were met in all patients with UAV and in none of the patients with BAV or TAV. Associated 95% confidence intervals were calculated for each estimate of sensitivity (94.7–100%) and specificity (98.1–100%), indicating that an adequate number of patients were included in each of the three groups. Conclusion The proposed echocardiographic score appears to be a specific and sensitive method to distinguish UAV from BAV and TAV. echocardiography, unicuspid aortic valve, preoperative assessment, echocardiographic score Introduction Unicuspid aortic valve (UAV) is a rare congenital cardiac valvular anomaly with an estimated prevalence of 0.02% in adults who are undergoing transthoracic echocardiography (TTE), frequently causing valve dysfunction, usually in the third to fifth decade of life.1,2 UAV is described as one of the main causes of congenital aortic valve stenosis and regurgitation in infants, children, and young adults.2,3 UAV is often misdiagnosed as the more prevalent bicuspid aortic valve (BAV), due to similar symptoms and characteristics during cardiac imaging.2 The diagnosis was previously based on autopsy or intraoperative inspection of the valve; the advance of cardiac imaging modalities, however, may allow diagnosis of UAV by TTE and transoesophageal echocardiographic (TOE) evaluation.4 Correct diagnosis can sometimes be complicated by the presence of calcification, and the number of commissures at the level of the sinotubular junction is critical in distinguishing between UAV and BAV.5 Precise information regarding valve morphology is crucial for aortic valve intervention, reconstruction, or replacement.6,7 However, the echocardiographic features to detect UAV and distinguish it from other morphologies are not well defined. Consequently, despite its important prognostic implications for patients, this disorder is mostly missed. This study aims to systematically determine the echocardiographic criteria to diagnose UAV morphology. Methods From August 2001 to May 2011, 69 patients underwent an aortic valve repair procedure for severe aortic regurgitation or stenosis and suspected UAV. The valve morphology was confirmed intraoperatively by one experienced surgeon (H.J.S.). To compare our echocardiographic findings with other valve morphologies, we investigated 99 consecutive patients with a BAV and 103 consecutive patients with a tricuspid aortic valve (TAV) who underwent isolated aortic valve surgery and were discussed by the Homburg Heart Team from May 2016 backwards. Patients with BAV were further scaled by the classification of Angelini.8 Based on our statistical analysis, a sufficient number of BAV and TAV patients was included to allow a statistically valid differentiation from patients with UAV. Echocardiographic assessment All patients underwent preoperative baseline examination that included an echocardiographic examination. TTE and TOE were performed on a Vivid 7 and E9 (General Electric, Frankfurt, Germany) machine by experienced echocardiographers. If the TTE image modality (parasternal short-axis) was adequate, no further TOE assessment was prompted. The analysis of the echocardiography was performed retrospectively by two experienced investigators who were blinded to the result of the intraoperative valve inspection and clinical parameters. Special attention was paid on known anatomic landmarks for the presence of a UVA such as a single commissural zone of attachment, a rounded leaflet-free edge on the opposite side of the commissural attachment zone and an eccentric valvular orifice (Figure 1).5 Figure 1 View largeDownload slide schematic illustration of an unicuspid aortic valve morphology, assessed from a 2D transthoracic parasternal short-axis view. Figure 1 View largeDownload slide schematic illustration of an unicuspid aortic valve morphology, assessed from a 2D transthoracic parasternal short-axis view. Statistical analysis Data are presented as mean ± standard deviation unless otherwise specified. Statistical comparisons between groups were performed using the Pearson’s χ2 test for categorical variables and the paired and unpaired t-test, the Wilcoxon rank-sum test, or the one-way-ANOVA for continuous variables wherever appropriate. Significance tests were two-tailed, with P-value of <0.05 considered significant. The clinical diagnosis of UAV using each of the defined criteria was used to determine the sensitivity and the specificity. The associated 95% confidence intervals were calculated for each of the estimates of sensitivity (94.7–100%) and specificity (98.1–100%), indicating an adequate number of patients had been included in each of the three groups to detect intergroup differences.9 Based on the sensitivity and the specificity of each individual criterion, the classification in the major and the minor criteria was determined. All statistical analyses were calculated using SPSS statistical software (version 20.0, SPSS Inc., Chicago, IL, USA). Results Table 1 depicts baseline patient characteristics. Mean patient age was 44.2 ± 12.8 years; 85% were male, with a mean body mass index of 26.2 ± 4.0 kg/m2 and a body surface area of 1.99 ± 0.26 cm/m2. Patients with UAV were younger, smaller and had been prescribed less medication than patients with BAV and TAV (P < 0.001 for all). None of the patients was diabetic. Predominant aortic stenosis was present in 18 (7%) patients, aortic regurgitation in 239 (88%) patients, and combined aortic valve disease in 14 (5%) patients. Table 1 Baseline characteristics Number of patients All patients UAV BAV TAV P-value n = 271 n = 69 n = 99 n = 103 Age (years), mean ± SD 44.2 ± 12.8 29.0 ± 13.0 43.3 ± 12.2 60.4 ± 13.2 <0.001 Male, n (%) 229 (85) 61 (88) 94 (95) 74 (72) <0.001 BMI (kg/m2), mean ± SD 26.2 ± 4.0 25.2 ± 4.5 27.4 ± 3.6 26.1 ± 3.8 0.028 BSA after Mosteller (m2), mean ± SD 1.99 ± 0.26 1.92 ± 0.32 2.09 ± 0.19 1.98 ± 0.19 <0.001 Coronary artery disease, n (%) 22 (8) 1 (2) 1 (1) 20 (19) <0.001 Hypertension, n (%) 168 (62) 29 (42) 51 (51) 88 (85) <0.001 Hypercholesterolemia, n (%) 71 (26) 18 (26) 8 (8) 45 (44) <0.001 Type 2 diabetes, n (%) 27 (10) 0 (0) 19 (40) 8 (8) 0.016 Cystatin GFR >60 mL/min/1.73 m2, n (%) 258 (95) 69 (100) 99 (100) 90 (87) 0.441 Number of all prescribed drugs, mean ± SD 0.9 ± 0.8 0.5 ± 0.6 1.0 ± 0.7 1.3 ± 1.1 <0.001 Number of patients All patients UAV BAV TAV P-value n = 271 n = 69 n = 99 n = 103 Age (years), mean ± SD 44.2 ± 12.8 29.0 ± 13.0 43.3 ± 12.2 60.4 ± 13.2 <0.001 Male, n (%) 229 (85) 61 (88) 94 (95) 74 (72) <0.001 BMI (kg/m2), mean ± SD 26.2 ± 4.0 25.2 ± 4.5 27.4 ± 3.6 26.1 ± 3.8 0.028 BSA after Mosteller (m2), mean ± SD 1.99 ± 0.26 1.92 ± 0.32 2.09 ± 0.19 1.98 ± 0.19 <0.001 Coronary artery disease, n (%) 22 (8) 1 (2) 1 (1) 20 (19) <0.001 Hypertension, n (%) 168 (62) 29 (42) 51 (51) 88 (85) <0.001 Hypercholesterolemia, n (%) 71 (26) 18 (26) 8 (8) 45 (44) <0.001 Type 2 diabetes, n (%) 27 (10) 0 (0) 19 (40) 8 (8) 0.016 Cystatin GFR >60 mL/min/1.73 m2, n (%) 258 (95) 69 (100) 99 (100) 90 (87) 0.441 Number of all prescribed drugs, mean ± SD 0.9 ± 0.8 0.5 ± 0.6 1.0 ± 0.7 1.3 ± 1.1 <0.001 BAV, bicuspid aortic valve; BMI, body mass index; BSA, body surface area; SD: standard deviation; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Table 1 Baseline characteristics Number of patients All patients UAV BAV TAV P-value n = 271 n = 69 n = 99 n = 103 Age (years), mean ± SD 44.2 ± 12.8 29.0 ± 13.0 43.3 ± 12.2 60.4 ± 13.2 <0.001 Male, n (%) 229 (85) 61 (88) 94 (95) 74 (72) <0.001 BMI (kg/m2), mean ± SD 26.2 ± 4.0 25.2 ± 4.5 27.4 ± 3.6 26.1 ± 3.8 0.028 BSA after Mosteller (m2), mean ± SD 1.99 ± 0.26 1.92 ± 0.32 2.09 ± 0.19 1.98 ± 0.19 <0.001 Coronary artery disease, n (%) 22 (8) 1 (2) 1 (1) 20 (19) <0.001 Hypertension, n (%) 168 (62) 29 (42) 51 (51) 88 (85) <0.001 Hypercholesterolemia, n (%) 71 (26) 18 (26) 8 (8) 45 (44) <0.001 Type 2 diabetes, n (%) 27 (10) 0 (0) 19 (40) 8 (8) 0.016 Cystatin GFR >60 mL/min/1.73 m2, n (%) 258 (95) 69 (100) 99 (100) 90 (87) 0.441 Number of all prescribed drugs, mean ± SD 0.9 ± 0.8 0.5 ± 0.6 1.0 ± 0.7 1.3 ± 1.1 <0.001 Number of patients All patients UAV BAV TAV P-value n = 271 n = 69 n = 99 n = 103 Age (years), mean ± SD 44.2 ± 12.8 29.0 ± 13.0 43.3 ± 12.2 60.4 ± 13.2 <0.001 Male, n (%) 229 (85) 61 (88) 94 (95) 74 (72) <0.001 BMI (kg/m2), mean ± SD 26.2 ± 4.0 25.2 ± 4.5 27.4 ± 3.6 26.1 ± 3.8 0.028 BSA after Mosteller (m2), mean ± SD 1.99 ± 0.26 1.92 ± 0.32 2.09 ± 0.19 1.98 ± 0.19 <0.001 Coronary artery disease, n (%) 22 (8) 1 (2) 1 (1) 20 (19) <0.001 Hypertension, n (%) 168 (62) 29 (42) 51 (51) 88 (85) <0.001 Hypercholesterolemia, n (%) 71 (26) 18 (26) 8 (8) 45 (44) <0.001 Type 2 diabetes, n (%) 27 (10) 0 (0) 19 (40) 8 (8) 0.016 Cystatin GFR >60 mL/min/1.73 m2, n (%) 258 (95) 69 (100) 99 (100) 90 (87) 0.441 Number of all prescribed drugs, mean ± SD 0.9 ± 0.8 0.5 ± 0.6 1.0 ± 0.7 1.3 ± 1.1 <0.001 BAV, bicuspid aortic valve; BMI, body mass index; BSA, body surface area; SD: standard deviation; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Table 2 illustrates echocardiographic values for the left ventricle and the proximal part of the ascending aorta. Eight (12%) patients with UAV, 30 (30%) patients with BAV, and 25 (24%) patients with TAV had normal sized left ventricular geometry and a preserved ejection fraction > 55%. Patients suffering from UAV had a higher mean ejection fraction than those with BAV (−3 ± 7%, P = 0.047) and TAV (−6 ± 8%, P < 0.001). The sinus diameter (1.84 ± 0.31 cm/m2, P < 0.001) and the sinus-tubular junction (1.68 ± 0.36 cm/m2, P < 0.001) of the ascending aorta were more pronounced in patients with BAV than those with UAV and TAV. Six (6%) patients with a BAV had no raphe (type 0) and 93 (94%) patients had a single raphe [type 1: 76/93 (82%) L-R, 13/93 (14%) R-N, and 4/93 (4%) N-L).8 Table 2 Echocardiographic parameters for the left ventricle and the proximal part of the ascending aorta Echocardiographic value [value related to BSA (cm/m2)] UAV BAV TAV P-value n = 69, mean ± SD n = 99, mean ± SD n = 103, mean ± SD MDAA 1.76 ± 0.38 1.8 ± 0.38 2.05 ± 0.52 0.45 LVEDD 3.0 ± 0.7 2.9 ± 0.39 2.93 ± 0.65 0.536 LVESD 2.04 ± 0.49 2.04 ± 0.34 2.12 ± 0.58 0.453 Annulus diameter 1.29 ± 0.25 1.32 ± 0.2 1.29 ± 0.23 0.64 Sinus diameter 1.7 ± 0.34 1.84 ± 0.31 1.72 ± 0.34 <0.001 STJ diameter 1.6 ± 0.34 1.68 ± 0.36 1.57 ± 0.42 <0.001 Ejection fraction (%) 58 ± 13 55 ± 11 52 ± 13 0.018 Echocardiographic value [value related to BSA (cm/m2)] UAV BAV TAV P-value n = 69, mean ± SD n = 99, mean ± SD n = 103, mean ± SD MDAA 1.76 ± 0.38 1.8 ± 0.38 2.05 ± 0.52 0.45 LVEDD 3.0 ± 0.7 2.9 ± 0.39 2.93 ± 0.65 0.536 LVESD 2.04 ± 0.49 2.04 ± 0.34 2.12 ± 0.58 0.453 Annulus diameter 1.29 ± 0.25 1.32 ± 0.2 1.29 ± 0.23 0.64 Sinus diameter 1.7 ± 0.34 1.84 ± 0.31 1.72 ± 0.34 <0.001 STJ diameter 1.6 ± 0.34 1.68 ± 0.36 1.57 ± 0.42 <0.001 Ejection fraction (%) 58 ± 13 55 ± 11 52 ± 13 0.018 BAV, bicuspid aortic valve; BSA, body surface area; LVEDD, left ventricle end-diastolic diameter; LVESD, left ventricle end-systolic diameter; MDAA, mean diameter of the aorta ascending; SD, standard deviation; SJT, Sino-tubular junction; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Table 2 Echocardiographic parameters for the left ventricle and the proximal part of the ascending aorta Echocardiographic value [value related to BSA (cm/m2)] UAV BAV TAV P-value n = 69, mean ± SD n = 99, mean ± SD n = 103, mean ± SD MDAA 1.76 ± 0.38 1.8 ± 0.38 2.05 ± 0.52 0.45 LVEDD 3.0 ± 0.7 2.9 ± 0.39 2.93 ± 0.65 0.536 LVESD 2.04 ± 0.49 2.04 ± 0.34 2.12 ± 0.58 0.453 Annulus diameter 1.29 ± 0.25 1.32 ± 0.2 1.29 ± 0.23 0.64 Sinus diameter 1.7 ± 0.34 1.84 ± 0.31 1.72 ± 0.34 <0.001 STJ diameter 1.6 ± 0.34 1.68 ± 0.36 1.57 ± 0.42 <0.001 Ejection fraction (%) 58 ± 13 55 ± 11 52 ± 13 0.018 Echocardiographic value [value related to BSA (cm/m2)] UAV BAV TAV P-value n = 69, mean ± SD n = 99, mean ± SD n = 103, mean ± SD MDAA 1.76 ± 0.38 1.8 ± 0.38 2.05 ± 0.52 0.45 LVEDD 3.0 ± 0.7 2.9 ± 0.39 2.93 ± 0.65 0.536 LVESD 2.04 ± 0.49 2.04 ± 0.34 2.12 ± 0.58 0.453 Annulus diameter 1.29 ± 0.25 1.32 ± 0.2 1.29 ± 0.23 0.64 Sinus diameter 1.7 ± 0.34 1.84 ± 0.31 1.72 ± 0.34 <0.001 STJ diameter 1.6 ± 0.34 1.68 ± 0.36 1.57 ± 0.42 <0.001 Ejection fraction (%) 58 ± 13 55 ± 11 52 ± 13 0.018 BAV, bicuspid aortic valve; BSA, body surface area; LVEDD, left ventricle end-diastolic diameter; LVESD, left ventricle end-systolic diameter; MDAA, mean diameter of the aorta ascending; SD, standard deviation; SJT, Sino-tubular junction; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Based on anatomic landmarks from the literature,5 our echocardiographic findings and the Homburg Heart Team discussion, the following echocardiographic diagnostic criteria were defined as major criteria to detect a UAV: (i) single commissural zone of attachment, (ii) rounded leaflet-free edge on the opposite side of the commissural attachment zone, (iii) eccentric valvular orifice during systole, and (iv) age <20 years and delta mean pressure gradient (dPmean) >15 mmHg. Age <40 years and an associated thoracic aortopathy (e.g. dilatation and aortic coarctation) were defined as minor criteria. The four major criteria (single commissural zone of attachment; rounded, leaflet-free edge on the opposite side of the commissural attachment zone; eccentric valvular orifice during systole; and age <20 years and dPmean >15 mmHg) were met by 68 (99%) patients, 63 (91%) patients, 68 (99%) patients, and 13 (19%) patients with a UAV, respectively (Figure 2). None of the patients with TAV fulfilled any of the major criteria (Table 3). The minor criteria of age <40 years and having an associated thoracic aortopathy were met in 56 (81%) patients and 30 (44%) patients with UAV, respectively. In patients with BAV, an associated thoracic aortopathy [aortic dilatation in 48 (48%) patients] was numerally more present. However, this difference did not reach statistical significance (P = 0.382 for all) compared with patients with UAV (44%) and TAV (34%). All patients with UAV met three out of the four major criteria or two out of the four major criteria and one minor criterion. This was not true for any of the patients with BAV or TAV. Table 3 Echocardiographic criteria to differentiate aortic valve morphology Echocardiographic criteria UAV BAV TAV P-value n = 69, n (%) n = 99, n (%) n = 103, n (%) Single commissural zone of attachment 68 (99) 7 (7) 0 (0) <0.001 Rounded leaflet-free edge on the opposite side of the commissural attachment zone 63 (91) 0 (0) 0 (0) <0.001 Eccentric valvular orifice during systole 68 (99) 12 (12) 0 (0) <0.001 Age <20 years and dPmean >15 mmHg 13 (19) 1 (1) 0 (0) <0.001 Age <40 years 56 (81) 37 (37) 10 (10) <0.001 Associated thoracic aortopathy 30 (44) 48 (48) 35 (34) 0.382 Echocardiographic criteria UAV BAV TAV P-value n = 69, n (%) n = 99, n (%) n = 103, n (%) Single commissural zone of attachment 68 (99) 7 (7) 0 (0) <0.001 Rounded leaflet-free edge on the opposite side of the commissural attachment zone 63 (91) 0 (0) 0 (0) <0.001 Eccentric valvular orifice during systole 68 (99) 12 (12) 0 (0) <0.001 Age <20 years and dPmean >15 mmHg 13 (19) 1 (1) 0 (0) <0.001 Age <40 years 56 (81) 37 (37) 10 (10) <0.001 Associated thoracic aortopathy 30 (44) 48 (48) 35 (34) 0.382 BAV, bicuspid aortic valve; dPmean, delta mean pressure gradient; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Table 3 Echocardiographic criteria to differentiate aortic valve morphology Echocardiographic criteria UAV BAV TAV P-value n = 69, n (%) n = 99, n (%) n = 103, n (%) Single commissural zone of attachment 68 (99) 7 (7) 0 (0) <0.001 Rounded leaflet-free edge on the opposite side of the commissural attachment zone 63 (91) 0 (0) 0 (0) <0.001 Eccentric valvular orifice during systole 68 (99) 12 (12) 0 (0) <0.001 Age <20 years and dPmean >15 mmHg 13 (19) 1 (1) 0 (0) <0.001 Age <40 years 56 (81) 37 (37) 10 (10) <0.001 Associated thoracic aortopathy 30 (44) 48 (48) 35 (34) 0.382 Echocardiographic criteria UAV BAV TAV P-value n = 69, n (%) n = 99, n (%) n = 103, n (%) Single commissural zone of attachment 68 (99) 7 (7) 0 (0) <0.001 Rounded leaflet-free edge on the opposite side of the commissural attachment zone 63 (91) 0 (0) 0 (0) <0.001 Eccentric valvular orifice during systole 68 (99) 12 (12) 0 (0) <0.001 Age <20 years and dPmean >15 mmHg 13 (19) 1 (1) 0 (0) <0.001 Age <40 years 56 (81) 37 (37) 10 (10) <0.001 Associated thoracic aortopathy 30 (44) 48 (48) 35 (34) 0.382 BAV, bicuspid aortic valve; dPmean, delta mean pressure gradient; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Figure 2 View largeDownload slide echocardiographic findings of aortic valve morphology, assessed from a 2D transoesophageal short-axis view (30–60°). BAV, bicuspid aortic valve; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Figure 2 View largeDownload slide echocardiographic findings of aortic valve morphology, assessed from a 2D transoesophageal short-axis view (30–60°). BAV, bicuspid aortic valve; TAV, tricuspid aortic valve; UAV, unicuspid aortic valve. Based on the individual analyses of the two experienced echocardiographers, 67 of 69 (97%) patients with UAV, 96 of 99 (97%) patients with BAV, and 102 of 103 (99%) patients with TAV were classified identically. In the six unequally evaluated morphologies, a decision was made by the Homburg Heart team. Discussion The increasing number of treatment options for aortic valve disease requires a precise definition of the valve pathology in order to choose the best treatment. Currently, the best morphological information is provided by echocardiography. UAV is a rare pathology, which may present as congenital stenosis, as regurgitation, or in conjunction with ascending aortic aneurysm. Unicuspid valves may be subject to repair, especially in juvenile patients or young adults.6 Therefore, the exact morphological diagnosis will be of marked clinical relevance. Congenital UAV is a rare pathology causing aortic valve disease in young adolescent and adults. However, this incidence is probably underestimated.10,11 Since many UAV are misdiagnosed as BAV by surgeons.10 When relying on echocardiographic studies the prevalence is probably even more underestimated because there are no generally accepted echocardiographic criteria which allow a precise differentiation between UAV, BAV, and TAV. Such a differentiation, however, is of increasing clinical importance. Earlier, when surgical aortic valve replacement was the only therapeutic option, a precise preoperatively anatomic characterization was of limited importance as the valve was excised irrespective of anatomical features. Currently, surgical aortic valve repair and transcatheter interventions have become clinically accepted modalities.7,12 Transcatheter interventions yield the most predictable results in the presence of TAV anatomy; its use in BAV is possible but controversially discussed,13,14 and there is no data on UAV. Considering the anatomical features and characterization of patients with UAV, even in the dynamic progress of transcatheter aortic valve implantation,15 till date or the near future, the interventional approach may only be a ‘bail out’ option (e.g. in case of contra indication for surgery) and not recommended on a routine basis.12 The detailed anatomic characterization is even more important if valve reconstruction is considered. Both BAV and UAV require very specific and individualized repair approaches.6,7,16 In the view of the anatomic variability and in order to facilitate echocardiographic analysis, we decided to create an echocardiographic score that allows the identification of UAV from BAV and TAV in a specific and sensitive way. A TAV is anatomically characterized by three commissures and three cusps with complete separation of cusp tissue.17 The BAV has two commissures of normal height which may vary in their circumferential orientation. In addition, there is very often a third, rudimentary commissure, which is of abnormally low height. The cusps are fused to a variable degree in the area of the rudimentary commissure, producing a raphe.18 UAVs occurs in acommissural (very rare) or unicommissural variants.5 Herein, we focus on the more common, the unicommissural valve. This valve pathology is characterized by one commissure of normal height, in our clinical experience almost always the one between left and non-coronary cusps. The two other commissures are most often hypoplastic, i.e. of subnormal height. There is a variable degree of cusp fusion adjacent to the hypoplastic commissures, thus two raphes may be seen.5 Therefore, the presence of two raphes is highly suggestive of unicuspid rather than bicuspid anatomy.18 These aspects may be visualized to different extent. A TAV will show on a short-axis view three commissures of similar height, which usually have an orientation of 120°. In systole opening of the cusps results in an orifice resembling a circle and complete in the area of the commissure. In BAV the height of the two functional commissures and the one rudimentary commissure may be difficult to define in the short-axis view. The fusion of cusp tissue adjacent to the rudimentary commissure is visible by incomplete opening in systole. Thus, in systole the cusps in the area of functioning commissures open completely resulting in a ‘fish mouth’ orifice. Extrapolating the anatomical characteristics of UAV, in echocardiography only one functional commissure of normal height would be expected in the short-axis view. This difference in commissural height may be suggested in the short-axis view: often a SAX will derive an image with the normal commissure open while the two rudimentary commissures are barely visible. This phenomenon can be difficult to quantify precisely with standard 2D imaging. The most striking finding is incomplete opening of the cusp tissue adjacent to the rudimentary cusps in a short-axis view, resulting in an eccentric circular orifice. This characteristic orifice in systole has also been observed by others.1 We have found the size of the opening area to vary, depending on the degree of stenosis. Since the valve assumes a funnel-shaped form in systole also this feature is best defined by 3D echocardiography. With appropriate imaging techniques correlates of these anatomic features of the UAV can be detected, which was the basis for our echocardiographic criteria. Based on our preoperative echo findings and the intraoperative visual examination above mentioned criteria were defined. Our study confirms that UAV can be identified by preoperative echocardiography using several criteria. The apparently most important are: single commissural zone of attachment, rounded leaflet-free edge on opposite side of the commissural attachment zone, and eccentric valvular orifice during systole. Furthermore, age <20 years and dPmean >15 mmHg were defined as major criteria. Age <40 years and an associated thoracic aortopathy (e.g. dilatation and aortic coarctation) were considered as minor criteria. In our experience, these echocardiographic findings are a specific and sensitive method to differentiate UAV both from BAV and TAV; this was confirmed by this study. Limitations Due to the study design, a potential selection bias contributing to the outcome of the results cannot be fully excluded. The echocardiographic assessment was performed by multiple operators; however, the retrospective analyses were conducted by two experienced operators from the Homburg Heart Team. Due to its 3D structure, 3D echocardiography might have helped to better differentiate the aortic valve morphology.19 BAV were scaled by the classification of Angelini8 and not by the classification Sievers and Schmidtke.18 Conclusion This echocardiographic score is a specific and sensitive method to differentiate UAV from BAV and TAV and might provide important benefits in the preoperative assessment of patients undergoing aortic valve procedures. Conflict of interest: None declared. Funding This retrospective analysis is an investigator initiated study without any funding. References 1 Novaro GM , Mishra M , Griffin BP. Incidence and echocardiographic features of congenital unicuspid aortic valve in an adult population . J Heart Valve Dis 2003 ; 12 : 674 – 8 . Google Scholar PubMed 2 Roberts WC , Ko JM. Frequency by decades of unicuspid, bicuspid, and tricuspid aortic valves in adults having isolated aortic valve replacement for aortic stenosis, with or without associated aortic regurgitation . Circulation 2005 ; 111 : 920 – 5 . http://dx.doi.org/10.1161/01.CIR.0000155623.48408.C5 Google Scholar CrossRef Search ADS PubMed 3 Miyamoto T , Sinzobahamvya N , Wetter J , Kallenberg R , Brecher AM , Asfour B et al. Twenty years experience of surgical aortic valvotomy for critical aortic stenosis in early infancy . Eur J Cardiothorac Surg 2006 ; 30 : 35 – 40 . Google Scholar CrossRef Search ADS PubMed 4 Evangelista A , Flachskampf FA , Erbel R , Antonini-Canterin F , Vlachopoulos C , Rocchi G et al. Echocardiography in aortic diseases: EAE recommendations for clinical practice . Eur J Echocardiogr 2010 ; 11 : 645 – 58 . Google Scholar CrossRef Search ADS PubMed 5 Anderson RH. Understanding the structure of the unicuspid and unicommissural aortic valve . J Heart Valve Dis 2003 ; 12 : 670 – 3 . Google Scholar PubMed 6 Aicher D , Bewarder M , Kindermann M , Abdul-Khalique H , Schäfers HJ. Aortic valve function after bicuspidization of the unicuspid aortic valve . Ann Thorac Surg 2013 ; 95 : 1545 – 50 . Google Scholar CrossRef Search ADS PubMed 7 Schäfers HJ , Aicher D , Riodionycheva S , Lindinger A , Radle-Hurst T , Langer F et al. Bicuspidization of the unicuspid aortic valve: a new reconstructive approach . Ann Thorac Surg 2008 ; 85 : 2012 – 8 . Google Scholar CrossRef Search ADS PubMed 8 Angelini A , Ho SY , Anderson RH , Devine WA , Zuberbuhler JR , Becker AE et al. The morphology of the normal aortic valve as compared with the aortic valve having two leaflets . J Thorac Cardiovasc Surg 1989 ; 98 : 362 – 7 . Google Scholar PubMed 9 Wilson EB. Probable Inference, the Law of Succession, and Statistical Inference . J Am Stat Assoc 1927 ; 22 : 209 – 12 . http://dx.doi.org/10.1080/01621459.1927.10502953 Google Scholar CrossRef Search ADS 10 Roberts WC. The congenitally bicuspid aortic valve. A study of 85 autopsy cases . Am J Cardiol 1970 ; 26 : 72 – 83 . Google Scholar CrossRef Search ADS PubMed 11 Mookadam F , Thota VR , Garcia-Lopez AM , Emani UR , Alharthi MS , Zamorano J et al. Unicuspid aortic valve in adults: a systematic review . J Heart Valve Dis 2010 ; 19 : 79 – 85 . Google Scholar PubMed 12 Baumgartner H , Falk V , Bax JJ , De Bonis M , Hamm C , Holm PJ et al. 2017 ESC/EACTS Guidelines for the management of valvular heart disease . Eur Heart J 2017 ; 38 : 2739 – 91 . Google Scholar CrossRef Search ADS PubMed 13 Hakeem A , Cilingiroglu M. Outcomes of TAVR in bicuspid aortic valve stenosis . J Am Coll Cardiol 2017 ; 70 : 1684 – 5 . http://dx.doi.org/10.1016/j.jacc.2017.06.071 Google Scholar CrossRef Search ADS PubMed 14 Yoon SH , Bleiziffer S , De Backer O , Delgado V , Arai T , Ziegelmueller J et al. Outcomes in transcatheter aortic valve replacement for bicuspid versus tricuspid aortic valve stenosis . J Am Coll Cardiol 2017 ; 69 : 2579 – 89 . http://dx.doi.org/10.1016/j.jacc.2017.03.017 Google Scholar CrossRef Search ADS PubMed 15 Kim WK , Hamm CW. The future of TAVI . Eur Heart J 2017 ; 38 : 2704 – 7 . http://dx.doi.org/10.1093/eurheartj/ehx474 Google Scholar CrossRef Search ADS PubMed 16 Schäfers HJ , Aicher D , Langer F , Lausberg HF. Preservation of the bicuspid aortic valve . Ann Thorac Surg 2007 ; 83 : S740 – 5 . Google Scholar CrossRef Search ADS PubMed 17 Loukas M , Bilinsky E , Bilinsky S , Blaak C , Tubbs RS , Anderson RH. The anatomy of the aortic root . Clin Anat 2014 ; 27 : 748 – 56 . Google Scholar CrossRef Search ADS PubMed 18 Sievers HH , Schmidtke C. A classification system for the bicuspid aortic valve from 304 surgical specimens . J Thorac Cardiovasc Surg 2007 ; 133 : 1226 – 33 . http://dx.doi.org/10.1016/j.jtcvs.2007.01.039 Google Scholar CrossRef Search ADS PubMed 19 Shiota T. Role of modern 3D echocardiography in valvular heart disease . Korean J Intern Med 2014 ; 29 : 685 – 702 . http://dx.doi.org/10.3904/kjim.2014.29.6.685 Google Scholar CrossRef Search ADS PubMed Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.

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European Heart Journal – Cardiovascular ImagingOxford University Press

Published: Jan 15, 2018

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