TAVR in Bicuspid vs. Tricuspid Aortic Valves in TVT Registry
- In a propensity-matched analysis of patients with bicuspid vs. tricuspid aortic stenosis in the STS/ACC TVT Registry who underwent TAVR with a self-expanding valve, there was no major difference in 30-day and 1-year mortality or stroke.
- Outcomes such as paravalvular aortic insufficiency in bicuspid aortic valve patients may improve with newer-generation (Evolut PRO) models.
How do the 30-day and 1-year outcomes differ for transcatheter aortic valve replacement (TAVR) in patients with bicuspid versus tricuspid aortic valves using a self-expanding prosthesis?
This is a retrospective review of the Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) Transcatheter Valve Therapy (TVT) Registry comparing outcomes of TAVR with a self-expanding prosthesis (Evolut R or Evolut PRO) in patients with tricuspid versus bicuspid aortic valves. Patients with previous transcatheter or surgical aortic valves who were undergoing a valve-in-valve procedure were excluded, as were emergent or salvage procedures and patients with “other” valve morphology.
Propensity-matching was performed using a multivariable logistic regression model with 28 baseline characteristics. Outcomes analyzed were: 30-day and 1-year mortality, stroke, and other procedure-specific outcomes including pacemaker implantation, coronary intervention, valve intervention, and life-threatening bleeding. Other endpoints included prosthetic valve function and quality of life (QOL), as assessed by the Kansas City Cardiomyopathy Questionnaire (KCCQ).
Of 27,086 patients who underwent commercial TAVR from July 2015-September 2018 who were not excluded for the reasons listed above, 932 patients had bicuspid aortic stenosis. Median follow-up was not significantly different between the two groups (79 days for bicuspid, 168 days for tricuspid, p = 0.60), and follow-up existed through December 2018. Unadjusted comparison showed that patients with bicuspid aortic valve were younger (72.9 ± 10.3 vs. 81.0 ± 7.6 years, p < 0.001), more frequently male (55.3% vs. 46.7%, p < 0.001), had lower STS Predicted Risk of Mortality (PROM) (5.3 ± 4.2% vs. 6.9 ± 4.8%, p < 0.001), and had less cardiovascular co-morbidity. Propensity-matching yielded 929 well-balanced pairs with absolute standardized differences < 0.10 across all measured baseline characteristics except for 5-m gait speed and hostile mediastinum.
After propensity-matching, there was no significant difference in all-cause mortality between bicuspid versus tricuspid groups at 30 days (2.6% vs. 1.7%, p = 0.18) or at 1 year (10.4% vs. 12.1%, p = 0.63), nor was there for stroke (3.4% vs. 2.7%, p = 0.93 at 30 days; 3.9% vs. 4.4%, p = 0.93). There were no significant differences in incidence of pacemaker implantation, coronary intervention, or life-threatening bleeding. Bicuspid valve patients required more aortic-valve re-intervention at 30 days (0.8% vs. 0.1%, p = 0.03) and at 1 year (1.7% vs. 0.3%, p = 0.01). They also had more moderate or severe aortic insufficiency (AI) at 30 days (5.6 vs. 2.1%, p < 0.001), though there was less moderate or severe AI in patients who received the newer-generation PRO valve. While mean gradients were significantly higher in the bicuspid group at 30 days, this difference did not persist at 1 year. QOL improved significantly in both groups with >32-point increase in KCCQ score for each group (p < 0.001). Procedures for bicuspid patients were longer (113.6 ± 61.0 vs. 105.1 ± 51.2 minutes, p = 0.001). Median length of stay for both groups was 2 days.
TAVR with a self-expanding prosthesis can be performed safely and effectively in patients with bicuspid aortic valve with outcomes comparable to patients with tricuspid valves.
This is another important analysis of TVT Registry data showing that TAVR can be performed safely and effectively in selected patients with bicuspid aortic valve who are at intermediate or higher risk for mortality and morbidity from surgical aortic valve replacement (SAVR). This adds to the analysis of the TVT Registry by Makkar RR, et al. (JAMA 2019;321:2193-202), which specifically looked at TAVR with a balloon-expandable prosthesis in bicuspid versus tricuspid aortic valve patients; that analysis showed comparable results between the two groups, as this study did.
Patients with bicuspid aortic valve are carefully evaluated by a Heart Team for co-morbidities and anatomic considerations, and TAVR is recommended for those who are thought likely to have a successful technical outcome. Otherwise, SAVR offers an effective way to address the unique considerations in patients with bicuspid aortic valve, as mentioned by the authors: a more oval orifice, bulky and asymmetric leaflet calcification, unusual coronary anatomy, annular measurements out of recommended range for TAVR, and concomitant aortopathy. Of note, patients with bicuspid aortic valve comprise only 3.4% of the patients in the registry.
Certainly, for both self-expanding and balloon-expanding TAVR valves, there have been device iterations with time – such as a “skirt” to reduce paravalvular AI, as well as lower profile devices that have reduced the diameter requirement for transfemoral access – that may have contributed to increased procedural success. Technology waits for no one, and the valves will continue to improve with time.
We should remember that we still do not yet know what the optimal aortic valve replacement strategy is for younger patients (like those with bicuspid aortic valve) who are likely to outlive two or more valves during their lifetime if they opt for tissue valves rather than a mechanical valve. Studies are needed to evaluate decision-making strategies that take into account age, risk and extent of re-operation(s), and device developments.
Keywords: Aortic Valve Insufficiency, Cardiac Surgical Procedures, Heart Valve Diseases, Heart Valve Prosthesis, Hemorrhage, Length of Stay, Pacemaker, Artificial, Percutaneous Coronary Intervention, Quality of Life, STS/ACC TVT Registry, Transcatheter Aortic Valve Replacement, Tricuspid Valve Insufficiency
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