Clinical and echocardiographic outcomes at 30 days and one year were similar between patients with bicuspid and tricuspid aortic stenosis following transcatheter aortic valve implantation (TAVI) with a self-expanding valve in a recent analysis from the TVT Registry. Researchers also noted that, in patients at increased surgical risk, TAVI for bicuspid aortic valve stenosis had acceptable safety outcomes with low complications rates.
Writing in JACC: Cardiovascular Interventions, John K Forrest (Yale School of Medicine, New Haven, Connecticut) and colleagues say: “In this analysis, among 929 pairs of propensity-matched patients undergoing TAVI in the United States between July 2015 and September 2018, there was no significant difference in all-cause mortality or stroke at 30 days or one year between patients with bicuspid versus tricuspid aortic valve anatomy. However, there was a small but increased number of patients in the bicuspid group who required aortic valve reintervention as compared with the tricuspid group at 30 days and at one year.”
Forrest et al point out that TAVI has shown excellent safety and efficacy in patients with tricuspid aortic valve stenosis, but limited data are available on the use of self-expanding valves in patients with bicuspid valves. The objective of their study was to compare outcomes in patients with bicuspid versus tricuspid anatomy undergoing TAVI. They used the Society of Thoracic Surgeons/American College of Cardiology TVT Registry to analyse patients who underwent TAVI with the Evolut R or Evolut PRO valves. Clinical and echocardiographic outcomes were analysed through one-year follow-up.
Between July 2015 and September 2018, a total of 932 patients with bicuspid aortic valve stenosis underwent elective TAVI with the self-expanding Evolut R or Evolut PRO valve. These patients were compared with a group of 26,154 patients with tricuspid aortic stenosis who underwent TAVI during that same time period. At baseline, patients with bicuspid valves were younger, had fewer cardiac comorbidities, and had lower Society of Thoracic Surgeons Predicted Risk of Mortality (PROM) scores (5.3±4.2% vs. 6.9±4.8%, p<0.001). To account for these differences, propensity matching was performed, which resulted in 929 matched pairs.
Among the propensity score–matched patients, there were no significant differences in procedural characteristics except for procedure time, which was longer for patients with bicuspid valves than for those with tricuspid valves (113.6±61 minutes vs. 105.1±51.2 minutes; p=0.001). The type of anaesthesia used (general anaesthesia in circa 58%) and route of valve delivery (iliofemoral approach in circa 92%) did not differ between the groups. The size and type of valve implanted, as well as device success rates, were also not different between the two groups.
There was no significant difference in all-cause mortality between the bicuspid and tricuspid groups at 30 days (2.6% vs. 1.7%; p=0.18) or one year (10.4% vs.12.1%; p=0.63). The incidence of stroke was also not different at 30 days (3.4% vs. 2.7%; p=0.41) or one year (3.9% vs. 4.4%; p=0.93). There was no significant difference in the incidence of pacemaker implantation, coronary intervention, or life-threatening bleeding between the bicuspid and tricuspid propensity-matched groups. There were more patients in the bicuspid group who required aortic valve reintervention as compared with the tricuspid group at both 30 days (0.8% vs. 0.1%; p=0.03) and one year (1.7% vs. 0.3%; p=0.01).
Additionally, say the researchers, “Valve haemodynamics were excellent for bicuspid and tricuspid patients post-procedure, and at one year.” Post-procedural effective valve area was 1.9 cm2 in both groups. Mean gradients for the bicuspid group were slightly higher post-procedure as compared with tricuspid patients but were not statistically different at one year. Post-procedure moderate or severe aortic regurgitation (AR) was more prevalent in patients with bicuspid aortic valves (5.6% vs. 2.1%; p < 0.001) at 30 days.
Examining by valve type, Evolut PRO versus the prior generation Evolut R, there was significantly less moderate or severe AR seen in patients who were implanted with the Evolut PRO valve. In addition, in patients implanted with the Evolut PRO valve, there was no difference seen in greater than mild AR at 30 days between the bicuspid and tricuspid groups (2.2% bicuspid vs. 1.5% tricuspid; p = 0.71).
Quality of life as assessed via the Kansas City Cardiomyopathy Questionnaire improved significantly from baseline to one year, and improvement in New York Heart Association functional class at one year occurred in most patients in both groups
The authors conclude: “Given intrinsic differences in bicuspid and tricuspid aortic valve anatomies and a lack of data around low-risk patients with bicuspid aortic valves, randomised studies evaluating TAVI in low-risk patients with bicuspid aortic valve disease are needed.” They concede that the study’s retrospective and observational design, using the TVT Registry, is a limitation.