Data on transcatheter aortic valve implantation (TAVI) for severe bicuspid aortic valve (BAV) stenosis and how this compares to that for tricuspid aortic valve (TAV) stenosis are limited. Twenty-one consecutive patients with BAV were treated with the Edwards or CoreValve bioprosthesis from November 2007 to December 2012 at San Raffaele Scientific Institute and Clinical Institute S. Ambrogio, Milan, Italy. Results were compared with a cohort of patients with TAV (n = 447) treated with the same bioprostheses over the same period. Procedural 1- and 12-month outcomes were examined as defined by the Valve Academic Research Consortium criteria. Patients with BAV were younger (76.7 ± 7.1 vs 79.8 ± 7.4 years, p = 0.06) and with a larger aortic annulus (25.0 ± 1.8 vs 23.6 ± 2.1 mm, p = 0.01). Device success (85.7% vs 94.4%, p = 0.10) was lower in patients with BAV. Although the 30-day composite safety end point (23.8% vs 21.0%, p = 0.76) was similar between the 2 groups, mortality rate at 30 days was higher (14.2% vs 3.6%, p = 0.02) in the BAV group. Cardiovascular mortality at 1 year did not differ significantly between the 2 groups (10.5% vs 7.4%, p = 0.62). In conclusion, transcatheter aortic valve implantation in high surgical risk patients with severe BAV stenosis appears to be feasible with mid-term cardiovascular mortality similar to that for patients with TAV. Early survival and device success, however, were lower for patients with BAV demonstrating that further studies are required to identify which subset of patients with BAV is best suited for transcatheter treatment.
Transcatheter aortic valve implantation (TAVI) has become the mainstay treatment for patients with symptomatic severe aortic stenosis in whom surgical aortic valve replacement is prohibitive because of high surgical risk. A number of studies, including randomized trials, have demonstrated that TAVI is associated with improvements in clinical outcomes in these high-risk patients. Bicuspid aortic valve (BAV), in contrast, is the commonest congenital aortic valve anomaly with a reported incidence of approximately 1% in the general population, often manifesting as aortic stenosis or aortic regurgitation (AR) later in life. Data on the role of TAVI in the treatment of severe BAV stenosis are limited because such patients were excluded from most clinical trials because of concerns regarding the elliptical annular anatomy, dilatation and fragility of the ascending aorta, as this can lead to uneven valve expansion, bioprosthesis malposition or malfunction, annular rupture, or aortic dissection. Furthermore, although previous small studies have demonstrated that TAVI in patients with BAV is feasible with both the Edwards (Edwards Lifesciences, Irvine, California) and the CoreValve (Medtronic, Minneapolis, Minnesota) bioprostheses, there is little information with regard to early- and mid-term clinical outcomes and how these compare with those of patients with tricuspid aortic valve (TAV). The aim of this study was thus to examine the procedural results and mid-term clinical outcomes in patients with BAV treated with TAVI and compare with those with TAV.
Methods
All patients with BAV (n = 21) treated with the Edwards or CoreValve bioprosthesis from November 2007 to December 2012 at the San Raffaele Scientific Institute, Milan, Italy and Clinical Institute S. Ambrogio, Milan, Italy were retrospectively analyzed. The diagnosis of BAV was made by an imaging specialist before the procedure by either transesophageal echocardiography or multislice computer tomography. Results were compared with a cohort of patients with TAV (n = 447) treated with the same bioprostheses over the same period. Patients were considered eligible for TAVI if they had a high or prohibitive risk for conventional surgical valve replacement, after being reviewed by a dedicated heart team. Details of the TAVI procedure had been previously reported. Valve choice was mostly dependent on aortic annulus size, although annular shape, degree of annular calcification, coronary ostia height, and aortic angulation were also contributing factors. Patients received dual antiplatelet therapy for 6 months after the procedure and only aspirin thereafter. Follow-up data were collected in all patients at 30 days. Further follow-up was performed through telephone contact or clinic visit. All patients provided informed consent for both the procedure and subsequent data collection and analysis.
TAVI-specific end points were defined according to the Valve Academic Research Consortium criteria. Device success was defined as successful vascular access, delivery and deployment of the device with successful retrieval of the delivery system, with the device in the correct anatomic location, and with an aortic valve area of >1.2 cm 2 , mean aortic valve gradient <20 mm Hg, and without moderate or greater AR. All patients were assessed at hospital discharge and at 30 days. The 30-day combined safety end point was a hierarchical composite of all-cause mortality, major stroke, life-threatening bleeding, acute stage 3 kidney injury, periprocedural myocardial infarction, major vascular complication, or repeat procedure for valve-related dysfunction. Mortality is reported as overall mortality and cardiovascular mortality.
Values are presented as mean ± SD or median (interquartile range [IQR]) for continuous variables or as counts and percentages for categorical variables. Continuous variables were compared by the independent sample t or Mann-Whitney U tests. Categorical variables were compared by the chi-square statistic or Fisher’s exact test. A p value of <0.05 was considered to be statistically significant and all reported p values are 2-sided. Analyses were carried out using SPSS for Windows, version 19.0 (SPSS Inc., Chicago, Illinois).
Results
Baseline characteristics for the 2 groups are summarized in Table 1 . Mean age of the BAV group was significantly lower compared with the TAV group (76.7 ± 7.1 vs 79.8 ± 7.4 years, p = 0.06) consistent with the fact that aortic stenosis in general tends to develop earlier in BAV. Aortic annulus size, however, was larger in patients with BAV (25.0 ± 1 vs 23.6 ± 2.1 mm, p = 0.01).
| Characteristic | BAV (n = 21) | TAV (n = 447) | p Value |
|---|---|---|---|
| Age (yrs) | 76.7 ± 7.1 | 79.8 ± 7.4 | 0.06 |
| Men | 12 (57) | 212 (47) | 0.38 |
| Body mass index (kg/m 2 ) | 26.6 ± 4.4 | 26.1 ± 4.6 | 0.70 |
| Diabetes mellitus | 6 (29) | 135 (30) | 0.87 |
| Hypertension | 14 (67) | 345 (77) | 0.27 |
| Ejection fraction (%) | 50.1 ± 12.4 | 52.0 ± 12.6 | 0.50 |
| Ejection fraction (<35%) | 4 (19) | 63 (14) | 0.53 |
| New York Heart Association class III/IV | 15 (71) | 301 (67) | 0.70 |
| Previous myocardial infarction | 4 (19) | 88 (20) | 0.94 |
| Previous percutaneous coronary intervention | 6 (29) | 96 (22) | 0.44 |
| Previous cardiac surgery | 3 (14) | 89 (20) | 0.53 |
| Peripheral artery disease | 7 (33) | 133 (30) | 0.73 |
| Cerebrovascular disease | 4 (19) | 72 (16) | 0.72 |
| Estimated glomerular filtration rate <60 ml/min | 11 (52) | 257 (58) | 0.64 |
| Chronic obstructive pulmonary disease | 7 (33) | 137 (31) | 0.79 |
| Logistic EuroSCORE (%) | 23.9 ± 12.0 | 24.4 ± 17.3 | 0.88 |
| Society of Thoracic Surgeons score (%) | 7.6 ± 4.2 | 7.8 ± 7.3 | 0.91 |
| Peak aortic transvalvular gradient (mm Hg) | 85.9 ± 20.9 | 84.5 ± 24.6 | 0.80 |
| Mean aortic valve gradient (mm Hg) | 54.4 ± 17.9 | 52.5 ± 16.0 | 0.65 |
| Aortic valve area (cm 2 ) | 0.70 ± 0.23 | 0.75 ± 0.50 | 0.65 |
| Aortic annulus size (mm) | 25.0 ± 1.8 | 23.6 ± 2.1 | 0.01 |
| AR grade | 1.05 ± 0.94 | 0.98 ± 0.97 | 0.74 |
| Mitral regurgitation grade | 1.29 ± 1.0 | 1.36 ± 0.93 | 0.72 |
Procedural characteristics are listed in Table 2 . The use of the CoreValve bioprosthesis was more common in the BAV group (61.9% vs 41.4%, p = 0.06). In the case of the Edwards bioprosthesis, valves with larger diameter were used in the BAV group (p = 0.03). Postdilatation was more commonly performed in the BAV group (52.4% vs 23.5%, p <0.01).
| Variable | BAV (n = 21) | TAV (n = 447) | p Value |
|---|---|---|---|
| Valve type | 0.06 | ||
| Edwards | 8 (38) | 262 (59) | |
| CoreValve | 13 (62) | 185 (41) | |
| Access | |||
| Edwards | 0.97 | ||
| Transfemoral | 7 (89) | 232 (89) | |
| Transapical | 1 (13) | 25 (10) | |
| Transaxillary | 0 | 4 (2) | |
| Transaortic | 0 | 1 (0.3) | |
| CoreValve | 0.23 | ||
| Transfemoral | 8 (62) | 143 (77) | |
| Transaxillary | 5 (39) | 36 (20) | |
| Transaortic | 0 | 6 (3) | |
| Valve size (mm) | |||
| Edwards | 0.03 | ||
| 23 | 2 (25) | 111 (42) | |
| 26 | 5 (63) | 148 (57) | |
| 29 | 1 (13) | 3 (1) | |
| CoreValve | 0.26 | ||
| 26 | 2 (15) | 69 (37) | |
| 29 | 10 (77) | 104 (56) | |
| 31 | 1 (8) | 12 (7) |
Patient outcomes after procedure, at 30 days and at 1 year are demonstrated in Table 3 . No significant differences were noted between the 2 groups with regard to postprocedural AR grade (1.15 ± 0.59 vs 0.92 ± 0.80, p = 0.21) after TAVI. Within the BAV group, comparison between the CoreValve and Edwards valve did not demonstrate any significant differences with regard to AR grade (1.23 ± 0.60 vs 1.0 ± 0.5, p = 0.38). Device success in the BAV group was high, although slightly lower compared with the TAV group (85.7% vs 94.4%, p = 0.10), without reaching statistical significance. This was largely due to a more frequent need for a second valve in the BAV group (9.5% vs 4.5%, p = 0.29). Regarding the reasons for the 2 second valve implantations in the BAV group, in one case this was due to severe AR after implantation of a 31-mm CoreValve that did not resolve after postdilatation, necessitating thus the implantation of a second 31-mm CoreValve at a lower position. In the other case, this was due to the upward migration of a 29-mm CoreValve that required the implantation of a second CoreValve of the same size. The final case of device failure in the BAV group was the result of aortic dissection after the implantation of a 26-mm Edwards valve requiring surgical treatment.
| Variable | BAV (n = 21) | TAV (n = 447) | p Value |
|---|---|---|---|
| Postprocedural | |||
| Transfusion ≥4 | 1 (5) | 52 (12) | 0.33 |
| Bleeding (life threatening) | 1 (5) | 62 (14) | 0.23 |
| Bleeding (major) | 4 (19) | 90 (20) | 0.90 |
| Bleeding (minor) | 1 (5) | 41 (9) | 0.49 |
| Periprocedural myocardial infarction | 0 | 6 (1) | 0.59 |
| Periprocedural stroke | 0 | 5 (1) | 0.63 |
| Valve migration | 1 (5) | 14 (3) | 0.73 |
| Coronary occlusion | 0 | 4 (1) | 0.66 |
| Conversion to open heart surgery | 1 (5) | 9 (2) | 0.39 |
| Major vascular complication | 2 (10) | 46 (10) | 0.91 |
| Acute kidney injury | 4 (19) | 142 (32) | 0.22 |
| AR (0–4) | 1.15 ± 0.59 | 0.92 ± 0.80 | 0.21 |
| AR ≥2 | 5 (24) | 97 (22) | 0.82 |
| AR ≥3 | 0 | 11 (3) | 0.47 |
| Peak aortic valve gradient (mm Hg) | 15.1 ± 5.4 | 18.8 ± 8.7 | 0.87 |
| Mean aortic valve gradient (mm Hg) | 10.3 ± 5.7 | 10.5 ± 4.7 | 0.28 |
| New pacemaker | 3 (14) | 67 (15) | 0.93 |
| Device success | 18 (86) | 422 (94) | 0.10 |
| 30-Day outcomes | n = 21 | n = 447 | |
| 30-Day mortality | 3 (14) | 16 (4) | 0.02 |
| Cardiovascular mortality | 2 (10) | 12 (3) | 0.07 |
| Composite safety end point | 6 (29) | 94 (22) | 0.41 |
| 1-Year outcomes | n = 19 | n = 378 | |
| 1-Year mortality | 6 (32) | 52 (14) | 0.03 |
| Cardiovascular mortality | 2 (11) | 28 (7) | 0.62 |
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