The aim of the study was to evaluate the transcatheter aortic valve replacement (TAVR) in high-risk patients with severe bicuspid aortic valve (BAV) stenosis and to compare the outcomes with a matched group of patients with tricuspid aortic valve. TAVR became an alternative treatment method in high-risk patients with symptomatic aortic stenosis; however, BAV stenosis is regarded as a relative contraindication to TAVR. The study population comprised 28 patients with BAV who underwent TAVR. BAV was diagnosed based on a transesophageal echocardiography. CoreValve and Edwards SAPIEN prostheses were implanted. The control group consisted of 84 patients (3:1 matching) with significant tricuspid aortic valve stenosis treated with TAVR. There were no significant differences between patients with and without BAV in device success (93% vs 93%, p = 1.0), risk of annulus rupture (0% in both groups), or conversion to cardiosurgery (4% vs 0%, respectively, p = 0.25). The postprocedural mean pressure gradient (11.5 ± 6.4 vs 10.4 ± 4.5 mm Hg, p = 0.33), aortic regurgitation grade ≥2 of 4 (32% vs 23%, p = 0.45), 30-day mortality (4% vs 7%, p = 0.68), and 1-year all-cause mortality (19% vs 18%, p = 1.00) did not differ between the groups. Echocardiography showed well-functioning valve prosthesis with a mean prosthetic valve area of 1.6 ± 0.4 cm 2 versus 1.7 ± 0.3 cm 2 (p = 0.73), a mean pressure gradient of 10.3 ± 5.4 versus 9.8 ± 2.8 mm Hg (p = 0.64), and aortic regurgitation grade ≥2 of 4 (22% vs 22%, p = 1.00) for the 2 groups. In conclusion, selected high-risk patients with BAV can be successfully treated with TAVR, and their outcomes are similar to those reported in patients without BAV.
Transcatheter aortic valve replacement (TAVR) is now regarded as a well-established treatment strategy in patients with severe symptomatic aortic stenosis who are at high risk for surgical aortic valve replacement and in those considered inoperable. This recommendation, however, is based on study results, which did not include patients with bicuspid aortic valve (BAV). Therefore, TAVR is relatively contraindicated in this category of patients. This limitation becomes an important issue in everyday clinical practice as BAV is a relatively common anomaly present in up to 2% of the population, and in those undergoing surgical aortic valve replacement, its prevalence is substantially greater. Although there have been some publications reporting feasibility of TAVR in BAV, these mainly covered single case studies and small cohorts of patients. The aim of the study was to evaluate the efficacy and safety of TAVR in patients with severe BAV stenosis and to compare the results with those achieved in a matched cohort of patients with tricuspid valve.
Methods
The study group comprised consecutive patients with severe (valve area <1.0 cm 2 or indexed valve area <0.6 cm 2 /m 2 in echocardiography) symptomatic BAV stenosis treated with transcatheter implantation of Medtronic CoreValve system (MCS; Medtronic, Inc, Minneapolis, Minnesota) and Edwards SAPIEN valves (ESV; Edwards Lifesciences, Inc, Irvine, California) in 5 academic centers in Poland. A local heart team consisting of cardiac surgeon, interventional cardiologist, and general cardiologist at each center qualified the patients for the procedure. The inclusion criteria for TAVR included high surgical risk (logistic EuroSCORE ≥20%, end-stage renal failure requiring dialysis, chronic pulmonary disease, and pulmonary hypertension defined as pulmonary artery systolic pressure >60 mm Hg) or other contraindications to surgery that are not included in the risk scores (“porcelain” aorta, previous chest radiotherapy, previous pulmonary lobectomy, cirrhosis with portal hypertension, previous chest surgery, and cognitive dysfunction due to neurologic disease). From January 1, 2009, to September 30, 2012, a total of 417 patients underwent TAVR and 28 (6.7%) of them had BAV. The transthoracic echocardiography and transesophageal echocardiography (TEE) were performed in all patients as part of the routine preprocedural assessment protocol. Visualization of 2 commissures delimiting 2 aortic leaflets in TEE short axis was regarded as the diagnostic criterion for BAV. Other echocardiographic parameters included aortic annulus, aortic root and ascending aorta diameters, aortic valve area, and peak and/or mean transvalvular gradient. In all patients, coronary angiography and angiograms of the ascending aorta, left subclavian (SC) artery, and iliac and femoral arteries were obtained. The appropriate measurements of peripheral vessel diameters, aortic annulus, and assessment of iliac and femoral vessel tortuosity, and calcifications were performed. A part of the study group also underwent multidetector computed tomography (MDCT). However, we have decided not to analyze these measurements as the MDCT was done in <50% of the patients. To objectively assess the feasibility and efficacy of TAVR in BAV, we matched (3:1) the study group with 84 patients with tricuspid aortic valve using the following variables: perioperative risk (logistic EuroSCORE), annulus diameter, delivery route, and type and size of the implanted bioprosthesis (control group).
The technical aspects of the TAVR procedure have been described elsewhere. Briefly, all the procedures were performed under general anesthesia with TEE guidance. Transfemoral access was preferred. Because of individual anatomic characteristics (femoral and SC artery diameters, tortuosity, and calcification of the arteries) and operators’ preferences, other vascular approaches were also used, including SC, direct aorta, and transapical access.
Femoral arterial access was secured with a PROSTAR 10 French XL (Abbott Vascular Devices, Redwood City, California) or in selected cases using surgical technique. The latter was also applied in all SC procedures. Direct aorta procedures were carried out using a partial upper J-sternotomy or right anterior thoracotomy. Transapical access was obtained with standard anterolateral minithoracotomy in the fifth intercostal space. Balloon predilatation was performed in all patients using undersized balloons. In selected cases, a postdilatation was performed to optimize the procedural results, at the discretion of the operators. The ESV was used in patients with annulus diameter of 18 to 24.5 mm and the MCS in annulus diameter of 20 to 29 mm. If both types of prosthesis were suitable, the choice was at the discretion of the operator. Because of earlier introduction of MCS, supported by widely available training program, this type of bioprosthesis was preferentially used in patients who were amenable to receive treatment with either valve.
To evaluate the acute procedural outcome, the aortic angiogram, invasive gradient measurement, diastolic pressure in aorta, left ventricular end-diastolic pressure, and TEE with color Doppler were performed. A common echocardiographic scale was used across the centers to assess the paravalvular regurgitation (PVLR): (0) none, (1) trivial, (2) mild, (3) moderate, and (4) severe.
All patients were treated with acetylsalicylic acid (75 mg/day). Naïve clopidogrel patients received a loading dose of 300 to 600 mg before or immediately after the procedure. After vascular access was secured, an adjusted dose of intravenous unfractionated heparin bolus (70 IU/kg) was administered to achieve an activated clotting time of 250 to 300 seconds.
As a part of the routine, postprocedural standard-of-care patients were observed at the intensive care unit for 48 to 72 hours. The individual length of stay depended mainly on the periprocedural complications. Thereafter, patients were transferred to a general cardiology unit and discharged home. The postprocedural antiplatelet pharmacotherapy comprised dose of 75 mg/day of clopidogrel continued for 6 months and 75 mg of acetylsalicylic acid lifelong. Oral anticoagulation was added if necessary. Transthoracic echocardiography was performed before discharge in all patients.
The follow-up was carried out at 30 days and 6 and 12 months and included clinical assessment, electrocardiography, and transthoracic echocardiography. Echocardiographic imaging was done by the same physician who performed the pre- and periprocedural studies. The data were prospectively collected and entered into the multicenter registry.
Device success and clinical end points were defined according to the standardized definitions for TAVR published by the Valvular Academic Research Consortium. The study end points were 30-day safety composite end point consisting of all-cause mortality, major and minor stroke, transient ischemic attack, myocardial infarction, major vascular complications, life-threatening or disabling bleeding, acute kidney injury stage 3 and the need for pacemaker implantation, and all-cause 12-month mortality. Device success was defined as successful implantation of a single prosthesis with its appropriate placement and function (aortic valve area >1.2 cm 2 , mean aortic valve gradient <20 mm Hg or peak velocity <3 mm/s, and no moderate-to-severe PVLR) and successful retrieval of the delivery system.
Quantitative data are presented as mean and SD or as median (interquartile range) and qualitative variables as numbers and percentages. An unpaired Student t test or Wilcoxon rank-sum test was used for comparison of quantitative variables, whereas the comparison of qualitative variables was performed with the 2-tailed Fisher’s exact test. Statistical significance was defined as p <0.05. Statistical analysis was performed using Medcalc (MedCalc Software bvba, Belgium), version 11, and Statistica (StatSoft, Inc.), version 12.
Results
Of the 417 TAVRs performed in 5 academic centers in Poland from January 1, 2009, to September 30, 2012, a total of 28 cases (6.7%) were identified as BAV (study group). There were no significant differences in the baseline, clinical, and echocardiographic characteristics between the study group and the control group, except for ascending aorta diameter, which was significantly larger in the study group ( Table 1 ).
| Characteristics | BAV (n = 28) | No-BAV (n = 84) | p Value |
|---|---|---|---|
| Age (years) | 77.6 ± 5.5 | 79.1 ± 6.8 | 0.70 |
| Men | 13 (46%) | 40 (48%) | 1.00 |
| Diabetes mellitus type 2 | 11 (39%) | 29 (35%) | 0.82 |
| Insulin | 4 (14%) | 10 (12%) | 1.00 |
| Oral drug | 7 (25%) | 19 (23%) | 1.00 |
| Hypertension | 17 (60%) | 55 (66%) | 0.82 |
| NYHA class III/IV | 20 (71%) | 66 (79%) | 0.61 |
| Coronary artery disease | 14 (50%) | 54 (64%) | 0.26 |
| Previous myocardial infarction | 11 (39%) | 26 (31%) | 0.49 |
| Previous percutaneous coronary intervention | 6 (21%) | 30 (36%) | 0.24 |
| Previous coronary bypass | 4 (14%) | 21 (25%) | 0.30 |
| Previous stroke | 8 (29%) | 14 (17%) | 0.27 |
| Peripheral artery disease | 6 (21%) | 29 (35%) | 0.24 |
| Chronic obstructive pulmonary disease | 6 (21%) | 17 (20%) | 1.00 |
| Pulmonary hypertension | 5 (18%) | 29 (35%) | 0.15 |
| Estimated glomerular filtration rate <60 mL/min | 12 (43%) | 36 (43%) | 1.00 |
| Logistic EuroSCORE | 19.2 ± 9.0 | 18.8 ± 8.7 | 0.99 |
| Aortic valve area (cm 2 ) | 0.6 ± 0.1 | 0.6 ± 0.2 | 0.24 |
| Aortic annulus size (mm) | 24.8 ± 2.4 | 24.1 ± 2.7 | 1.00 |
| Mean pressure gradient (mm Hg) | 55.5 ± 17.6 | 52.5 ± 18.9 | 0.96 |
| Ascending aorta (mm) | 38.9 ± 6.2 | 33.8 ± 3.8 | 0.04 |
| Aortic regurgitation (0–4) | 1.3 ± 1.1 | 1.2 ± 0.9 | 0.61 |
| Mitral regurgitation (0–4) | 1.4 ± 1.0 | 1.6 ± 0.8 | 0.44 |
| Ejection fraction | 48.1 ± 13.1 | 49.8 ± 14.0 | 0.69 |
| Ejection fraction <40% | 7 (25%) | 19 (23%) | 1.00 |
All procedures were performed under general anesthesia. An intraprocedural TEE was routinely conducted to optimize the valve placement and to evaluate the bioprosthesis function. The transfemoral approach was used in >3/4 of patients ( Table 2 ). In all procedures, preimplantation balloon valvuloplasty with undersized balloon was performed. The postdilatation was used in selected cases accounting for 25% in the study group and 18% in the control group (p = 0.41). Most patients received the MCS that was equally distributed in both groups (82%). Details regarding the prosthesis type and size as well as the vascular access route are listed in Table 2 .
| Variable | BAV (n = 28) | No-BAV (n = 84) | p Value |
|---|---|---|---|
| Access | |||
| Edwards | 5 (18%) | 15 (18%) | 1.00 |
| Transfemoral | 3 (11%) | 9 (11%) | 1.00 |
| Transapical | 2 (7%) | 6 (7%) | 1.00 |
| CoreValve | 23 (82%) | 69 (82%) | 1.00 |
| Transfemoral | 19 (68%) | 56 (68%) | 1.00 |
| Transaortic | 1 (4%) | 3 (4%) | 1.00 |
| Transsubclavian | 2 (7%) | 6 (7%) | 1.00 |
| Transapical | 1 (4%) | 3 (4%) | 1.00 |
| Transfemoral access TOTAL | 22 (79%) | 65 (78%) | 1.00 |
| Valve type/size (mm) | |||
| Edwards | |||
| 23 | 3 (11%) | 9 (11%) | 1.00 |
| 26 | 1 (4%) | 3 (4%) | 1.00 |
| Corevalve | |||
| 23 | 1 (4%) | 3 (4%) | 1.00 |
| 26 | 2 (7%) | 6 (7%) | 1.00 |
| 29 | 18 (63%) | 54 (64%) | 1.00 |
| 31 | 3 (11%) | 9 (11%) | 1.00 |
The incidence of periprocedural and in-hospital complications was comparable in both groups, and device success was achieved similarly in both groups ( Table 3 ). No annulus rupture, aortic dissection, or death was observed during TAVR. In 2 patients from the study group and 3 patients from the control group, technical difficulties were reported. In 1 patient from the study group and 2 patients from the control group, the MCS was dislodged to the ascending aorta during implantation. Nonetheless, all procedures were securely completed. In 1 case, the valve was retrieved to the delivery system, repositioned, and successfully implanted. In the remaining 2 cases, the valves were completely removed and new bioprostheses were implanted. One patient from the control group had a severe PVLR, likely caused by too low MCS position. A second prosthesis was introduced, and the PVLR was decreased to mild (2+). Conversion to open heart surgery was required in another patient from the study group because of ESV embolization into the left ventricle.
| Variable | BAV (n = 28) | No-BAV (n = 84) | p Value |
|---|---|---|---|
| Transfusions ≥4 units of red blood cells | 3 (11%) | 7 (8%) | 0.71 |
| Bleeding (life-threatening) | 3 (11%) | 12 (14%) | 0.76 |
| Bleeding (major and minor) | 9 (32%) | 25 (30%) | 1.00 |
| Periprocedural myocardial infarction | 0 | 2 (2%) | 1.00 |
| Periprocedural cerebrovascular accident | 0 | 3 (4%) | 0.57 |
| Vascular complication (any) | 3 (11%) | 20 (24%) | 0.18 |
| Major vascular complications | 0 | 2 (2%) | 1.00 |
| Acute kidney injury (stage III) | 0 | 1 (1%) | 1.00 |
| Pericardial effusion | 0 | 3 (4%) | 0.57 |
| Permanent pacemaker implantation | 8 (29%) | 28 (33%) | 0.82 |
| CoreValve | 7 (25%) | 25 (30%) | 0.81 |
| Edward Sapien | 1 (4%) | 3 (4%) | 1.00 |
| Conversion to open-heart surgery | 1 (4%) | 0 (0%) | 0.25 |
| Valve migration | 1 (4%) | 2 (2%) | 1.00 |
| Ejection fraction (%) | 50.8 ± 18.2 | 52.1 ± 11.5 | 0.67 |
| Aortic prosthetic valve area (cm 2 ) | 1.54 ± 0.3 | 1.61 ± 0.2 | 0.22 |
| Mean gradient (mm Hg) | 11.5 ± 6.4 | 10.4 ± 4.5 | 0.33 |
| Aortic regurgitation ≥2 | 9 (32%) | 19 (23%) | 0.45 |
| Mitral regurgitation ≥2 | 4 (14%) | 21 (25%) | 0.30 |
| Hospital stay, days | 21.0 ± 11.0 | 19.2 ± 11.7 | 0.53 |
| 30-Day mortality | 1 (4%) | 6 (7%) | 0.68 |
| Device success | 26 (93%) | 78 (93%) | 1.00 |
| 30-Day combined safety endpoint | 5 (18%) | 19 (23%) | 0.79 |
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