Patients with bicuspid aortic stenosis may benefit as much from transcatheter aortic valve implantation (TAVI) as those with tricuspid aortic stenosis, according to the findings of two studies presented at TVT 2021 (The Structural Heart Summit, 20–22 July, Miami Beach, USA & virtual).
John Forrest (Yale School of Medicine, New Haven, USA) presented findings of a comparison of one-year outcomes after TAVI in low-risk patients with bicuspid and tricuspid aortic stenosis at the podium during a late-breaking TAVI trial session at TVT 2021. The study is part of the Evolut Low Risk study programme, examining patients receiving the Evolut R and PRO devices (Medtronic).
Forrest told attendees, attending both in person and via a digital livestream, that patients with bicuspid aortic valve anatomy have until now been excluded from many of the major randomised TAVI trials, including recent studies in the low-risk population. However, he noted that these patients are not uncommon, pointing out that bicuspid valve anatomy is present in up to 50% of low-risk patients referred for aortic valve replacement.
“We have previously published the primary outcomes from the single-arm Low Risk Biscupid study, which demonstrated that TAVI with a self-expanding supra-annular valve resulted in favourable results”, he said, noting that this includes a low rate of all-cause mortality or disabling stroke at 30 days (1.3%).
The latest analysis reports the one-year outcomes and directly compares TAVI results in low-risk patients with bicuspid anatomy to that in low-risk patients with three-leaflet aortic valves.
The Low Risk Bicuspid study was a prospective, single-arm study that enrolled 150 patients at 25 sites in the USA. A screening committee confirmed bicuspid type using CT analysis, and the valve size was based upon annular measurements. An independent clinical events committee adjudicated all serious adverse events, and an independent core laboratory assessed all echocardiograms.
For the analysis, 150 patients form the Low Risk Bicuspid study were propensity matched to the TAVI patients in the randomised Evolut Low Risk trial.
Propensity matching was performed for patients who received either an Evolut R or an Evolut PRO valve, with variables including age, sex, body surface area, STS score and a number of cardiovascular risk factors—which matched 145 patients in both the Evolut Low Risk Bicuspid and Tricuspid arms.
Bicuspid patients tended to be younger than those in the tricuspid arm, Forrest said (70.3 vs. 74 years, p<0.001), a higher proportion were female (48% vs. 37.7%, p=0.019), and a lower proportion had prior percutaneous coronary intervention (PCI, 7.3% vs. 14.1%, p=0.0024). Forrest remarked that recent data have shown an increasing prevalence regarding coronary disease and tri-leaflet aortic stenosis, but as it relates to bicuspid disease “that may not be the case”.
“Device success was excellent,” Forrest commented, adding that there were no significant differences between matched bicuspid and tricuspid patients in terms of clinical outcomes including death or disabling stroke, major bleeding, pacemaker implantation, rehospitalisation, or valve thrombosis at one year. Valve haemodynamics were “excellent”, regardless of whether the native valve was bicuspid or tricuspid, Forrest added.
One of the areas of concern for bicuspid valves in early data was the risk of paravalvular regurgitation, Forrest commented, adding that in bicuspid patients at one year 78.7% of patients had no or trace paravalvular regurgitation, compared to 57.4% of tricuspid patients. Incidences of severe and moderate paravalvular regurgitation were low in both arms.
“From this study what we have seen is that the presence of a bicuspid valve did not result in differences in major clinical outcomes at one year between propensity matched low-risk patients undergoing transcatheter aortic valve replacement,” Forrest told TVT attendees. Patients with a bicuspid valve underwent pre-implant valvuloplasty significantly more frequently, he added, although noted that there was no clinical difference in post-dilatation or stroke.
“I think we can conclude from this that the presence of a bicuspid valve does not appear to impact procedural or early outcomes at one year in low-risk patients undergoing TAVI using a self-expanding, supra-annular valve,” Forrest said in his concluding statement.
He added that it is likely that calcium distribution appears to impact outcomes more than the number of leaflets. However, he cautioned against potential bias in interpreting the results, remarking: “It is important to note that the results of all of these low-risk studies, both for three-leaflet as well as bicuspid patients, cannot be extrapolated to include all patients regardless of their anatomy.
“Regardless of the number of leaflets, vigilant case planning and focus by the heart team on the CTA [coronary computed tomography] is critical for success in these low-risk patients.”
Following Forrest, Matthew Williams (NYU Langone Health, New York, USA) presented results from the PARTNER 3 Bicuspid registry, comparing the one-year safety and efficacy of the Sapien 3 (Edwards Lifesciences) TAVI system in selected low risk patients with severe symptomatic aortic stenosis and bicuspid anatomy to a clinically similar cohort of patients with tricuspid anatomy treated in the PARTNER 3 trial.
Williams told TVT delegates that the results showed that the composite primary endpoint of death, stroke or cardiovascular rehospitalisation related to valve or procedure and heart failure at one year were similar for both the bicuspid and tricuspid cohorts, 10.9% vs. 10.2%, respectively (p-value=0.9).
The individual components of the primary endpoint were also similar at one year (bicuspid vs. tricuspid: 0.7% vs. 1.4% mortality; 2.1% vs. 2% stroke; 9.6% vs. 9.5% rehospitalisation related to valve or procedure and heart failure). Additionally, the new pacemaker implantation rate was similar between the two groups (6.8% vs. 7.4%).
Both cohorts experienced similar symptomatic relief and quality of life gains at 30 days and one year when measured by both the New York Heart Association (NYHA) Classification and the Kansas City Cardiomyopathy Questionnaire (KCCQ), Williams explained.
“Patients with severe, symptomatic aortic stensosis who are low surgical risk with favourable bicuspid anatomy who underwent TAVI with the Sapien 3 valve demonstrated haemodynamic outcomes and adverse events that were comparable to a similar group with tricuspid anatomy,” Williams concluded. “They had a similar quality of life and symptomatic improvement, and longer term follow-up will obviously be necessary and continued in these patients.”