Transcatheter aortic valve replacement in bicuspid versus tricuspid aortic valves from the STS/ACC TVT registry
Selected in JACC: Cardiovascular Interventions by D. Giacoppo
TAVR with self-expandable bioprosthesis appears to be an acceptable therapeutic strategy in patients with bicuspid aortic valve disease.
References
Authors
Forrest JK, Kaple RK, Ramlawi B, Gleason TG, Meduri CU, Yakubov SJ, Jilaihawi H, Liu F and Reardon MJ
Reference
JACC: Cardiovascular Interventions. DOI: 10.1016/j.jcin.2020.03.022
Published
May 2020
Link
Read the abstractReviewer
My Comment
Why this study? – the rationale/objective
Several randomised clinical trials have demonstrated that TAVR is safe and effective as compared with surgical aortic valve replacement, regardless of the surgical risk profile of patients. However, in all these trials bicuspid valve disease was among exclusion criteria.
Bicuspid aortic valve disease is the most frequent congenital heart defect, with a prevalence of 0.5-2.0%, and the incidence of stenosis in this anatomic substrate is higher than in tricuspid aortic valve and occurring at a relatively younger age.
There is a paucity of large-scale data on the treatment of bicuspid aortic valve stenosis with TAVR. A recent analysis from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy (TVT) registry including only patients who underwent TAVR with SAPIEN 3 balloon-expandable prosthesis showed comparable major clinical outcomes between bicuspid and tricuspid aortic valve disease at 30 days and 1 year. However, whether also TAVR with self-expandable prosthesis is effective and safe in the treatment of bicuspid aortic valve stenosis is less clear.
How was it executed? – the methodology
The TVT registry serves as the national database for medical device tracking of all commercially available transcatheter aortic valves implanted in the United States. Entry of patients is mandatory and performed by each individual site. Random audit of 10% of data elements is performed on-site, remotely, or both.
Between July 2015 and September 2018, a total of 37903 patients with aortic valve stenosis underwent elective TAVR with the supra-annular, repositionable, self-expandable Evolut R and Evolut PRO prostheses. The Evolut PRO valve shares the same design as the Evolut R valve, except for the addition of an outer pericardial tissue wrap to reduce paravalvular leak. After exclusion of valve-in-valve procedures, emergency or salvage interventions, and records with unspecified aortic valve morphology, a total of 27086 patients remained. Of them, 932 had bicuspid aortic valve stenosis. To account for differences between bicuspid and tricuspid aortic valve groups, propensity score matching by multivariable logistic regression with 28 baseline characteristics was performed with identification of 929 pairs. Missing data was handled by imputation. In-hospital outcomes were compared by using the chi-square test, while 30-day and 1-year outcomes were compared by using the log-rank test.
The endpoints of interest were defined according to the Valve Academic Research Consortium.
What is the main result?
The unadjusted database revealed that patients with bicuspid aortic valve were younger, more frequently men, had lower Society of Thoracic Surgeons Predicted Risk of Mortality (STS PROM) score and less prior cardiovascular interventions (percutaneous coronary intervention, coronary artery bypass grafting, pacemaker/defibrillator) compared with those with tricuspid aortic valve. Patients with bicuspid aortic valve showed higher maximum aortic valve velocity, mean aortic valve gradient, and annular size and lower left ventricular ejection fraction, moderate-to-severe mitral regurgitation, and severe tricuspid regurgitation as compared with those with tricuspid aortic valve. After propensity score matching, the two groups became well balanced for almost all variables.
There were no significant differences between bicuspid and tricuspid aortic valve stenosis for major in-hospital events, including death, stroke, myocardial infarction, coronary obstruction, pacemaker implantation, and vascular complications. However, mean aortic valve gradient ≥20 mmHg (5.9% vs. 3.2%, p=0.009) and moderate-to-severe post-procedure aortic regurgitation (5.6% vs. 2.1%, p<0.001) were higher in patients with bicuspid aortic valve. At 30 days, there were no significant differences in all-cause mortality (2.6% vs. 1.7%, p=0.18) and stroke (3.4% vs. 2.7%, p=0.41) between bicuspid and tricuspid groups. At 1 year, differences between groups remained nonsignificant in terms of both all-cause death (10.4% vs. 12.4%, p=0.63) and stroke (3.9% vs. 4.4%, p=0.93). At 30 days and 1 year, no significant differences in myocardial infarction, pacemaker implantation, coronary intervention, or life-threatening bleeding between groups was observed. However, patients with bicuspid aortic valve required more frequently aortic valve reintervention at both 30 days (0.8% vs. 0.1%, p=0.03) and 1 year (1.7% vs. 0.3%, p=0.01).
Illustration credit: JACC: Cardiovascular Interventions, May 2020. DOI: 10.1016/j.jcin.2020.03.022
Critical reading and the relevance for clinical practice
Bicuspid aortic valve disease anatomy is often more challenging that tricuspid aortic valve disease due to the asymmetric bulky leaflet calcification and fused raphe, larger and more asymmetric annuli, increased incidence of aortopathy with dilation of the aortic root and ascending aorta, and more frequent atypical location of coronary artery ostia. These unfavorable characteristics can lead to more difficult valve positioning and stable anchoring as well as to a higher number of complications and incidence of paravalvular leak.
The results of the study of Forrest and colleagues show low rates of in-hospital complications and adverse events after TAVR for bicuspid aortic valve stenosis compared with tricuspid aortic valve stenosis. At 1 year, these favorable results remained consistent, with quite similar incidences of all-cause death and stroke between bicuspid and tricuspid groups. Of note, at long-term follow-up valve thrombosis, pacemaker implantation, and need for percutaneous coronary intervention remained also comparable between groups. However, aortic valve reintervention incidence resulted to be higher in bicuspid aortic valve patients at both 30 days and 1 year and the concurrent higher rates of moderate-to-severe post-procedure aortic regurgitation in the same group may provide a reasonable explanation for this finding. On the other hand, in a sensitivity analysis moderate-to-severe aortic regurgitation seemed to be driven by patients who received an old-generation valve (i.e., Evolut R).
The results of this study need to be viewed in light of a number of considerations. First, the design of the TVT registry imposes some limitations in the extent of variables collected and the self-reported adjudication of the outcomes may have introduced bias. Second, although propensity score matching was used to balance the two groups, some unmeasured characteristics (e.g. bicuspid aortic valve type) might still have had an influence on the results. Third, only individual endpoints were analysed and, despite the large number of patients included in this study, some nonsignificant differences, especially with respect to in-hospital mortality, might be function of the limited statistical power. On the other hand, the long-term comparison between bicuspid and tricuspid groups did not reveal differences with a large margin of nonsignificance in terms of the hard endpoints of all-cause death and stroke. Finally, echocardiography data were missing in a significant proportion of patients and functional information at long-term follow-up was fragmentary. Higher quality data are needed to better understand potential advantages and limitations of TAVR for bicuspid aortic valve stenosis.
In conclusion, TAVR with self-expandable bioprosthesis appears to be an acceptable therapeutic strategy in patients with bicuspid aortic valve disease, though a higher incidence of reintervention compared with tricuspid aortic valve disease was observed. The most important unaddressed questions remain the durability of the effects observed at 1 year in this challenging setting and the performance of TAVR in bicuspid aortic valve stenosis as compared with the traditional surgical approach.
No comments yet!