Transcatheter aortic valve implantation (TAVI) procedures had a high rate of success and low risk of death or disabling stroke at 30 days in patients with a bicuspid aortic valve, according to research presented by Basel Ramlawi (Valley Health, Winchester, USA) during a late-breaking clinical trial session on day two of the American College of Cardiology/World Congress of Cardiology’s virtual scientific sessions (ACC.20/WCC Virtual).
These were conclusions of the Evolut Low Risk Bicuspid Study, which sought to evaluate the safety and efficacy of the Evolut (Medtronic) TAVR system in bicuspid aortic valve patients at low surgical risk for early mortality. “These findings point to a potentially less invasive treatment for patients who otherwise would undergo open heart surgery due to their anatomical valve structure,” said Ramlawi, a co-primary investigator of the study who presented the data at the meeting. “We feel confident that these primary early outcomes provide additional evidence that the Evolut TAVR platform is a suitable treatment option for patients with bicuspid valves who have previously been left out of TAVR trials.”
Bicuspid aortic valve disease (BAVD) is an abnormality of the aortic valve resulting in the patient having two functional valve leaflets instead of the more common three leaflets (tricuspid). Often bicuspid aortic stenosis patients are younger than tricuspid patients (median age of 70 in the study).
During his presentation, Ramlawi noted that TAVR is the standard of care in patients at intermediate or higher risk of early surgical mortality. This has recently been shown to be non-inferior to surgery in low-risk patients, Ramlawi said, noting that pivotal TAVR trials have excluded patients with bicuspid aortic valves, “due to anatomic issues, as well as technical concerns about implantation”.
The prospective, multicentre study involved 150 patients with severe bicuspid aortic stenosis at low risk of 30-day mortality who underwent TAVR at 25 centres across the US. Patients were treated with the Evolut R (23, 26, 29, 34mm) or the Evolut PRO (23, 26, 29mm) self-expanding, supra-annular, repositionable valves. Those included in the study had a bicuspid aortic valve anatomy confirmed by multi-slice computed tomography. Patients under the age of 60 years were excluded from the study, as were those with significant ascending aortopathy requiring surgical repair, or an ascending aorta diameter of less than 4.5cm.
Thirty day follow-up was completed in 147 of the participating patients. The primary safety endpoint assessed was death or disabling stroke at 30 days, and the primary efficacy endpoint comprised device success involving the absence of procedural death and correct positioning of one valve in the proper location, as well as absence of moderate or severe total aortic regurgitation at 18 hours to seven days.
The study showed low rates of all-cause mortality or stroke at 30 days (1.3%) with a low rate of serious procedural complications, and no annular rupture or aortic dissection. The study was presented as part of the American College of Cardiology together with World Congress of Cardiology Scientific Sessions (ACC.20/WCC) meeting.
Results from the study showed positive outcomes at 30 days, with a 95.3% device success rate and a low rate of serious procedural complications including no annular ruptures or aortic dissection. In addition, results from the study showed:
- Low rate of all-cause mortality (0.7%)
- Low rate of disabling stroke (0.7%)
- Exceptional haemodynamics with low mean AV gradients (7.6 ± 3.7 mm Hg), and large effective orifice area (2.3 ± 0.7 cm2)
- No incidence of moderate or severe paravalvular leak (PVL)
- Low rate of major vascular complications (1.3%)
- High utilisation of the Evolut 34 mm (41.6% of patients in the study were implanted with this larger valve size)
- New pacemaker rate (15.1%) was lower than in the Evolut Low Risk Trial
Summarising his findings, Ramlawi said: “TAVR with a supra-annular, self-expanding valve in low risk bicuspid patients achieved excellent early results, consistent with annular sizing. With 95% device success, low mortality and stroke at 30 days of 1.3%, and low risk of aortic insufficiency with no moderate or severe aortic insufficiency in this population.”
Ramlawi said that study limitations include the fact that all patients received TAVR, rather than providing a randomised comparison between TAVR and open-heart surgery. In addition, the study was conducted in medical centres that perform a high volume of TAVR procedures, and it is unclear whether a similarly high success rate would be achievable in centres with less TAVR experience. The researchers plan to continue to track outcomes in the patients for 10 years to assess the long-term efficacy of the TAVR-implanted valves.
