Results of a study presented at the American College of Cardiology's Annual Scientific Session on March 29 demonstrated “excellent” outcomes following transcatheter aortic valve replacement (TAVR) using the Medtronic plc Evolut in low surgical risk patients with bicuspid aortic valve stenosis. Patients who had the minimally invasive procedure experienced low rates of all-cause mortality and stroke at 30 days.

“These findings point to potentially less invasive treatment for patients who otherwise would undergo open-heart surgery due to their anatomical valve structure,” said study co-primary investigator Basel Ramlawi, of Valley Health System in Winchester, Va.

Compared to open-heart surgery, TAVR typically permits quicker recovery for patients with fewer transfusions and less post-procedural arrhythmia, Ramlawi told BioWorld.

“This study shows that excellent early outcomes with TAVR are possible in bicuspid patients,” Ramlawi said. “While these are very early (30-day) outcomes, TAVR early safety and efficacy was excellent in this selected patient population.”

The study

The Low Risk Bicuspid Study enrolled 150 patients, all with bicuspid aortic valve disease (BAVD), a congenital heart defect. The disease affects 3% to 5% of the general population, according to Ramlawi. People with BAVD have an aortic valve with two functional valve leaflets instead of the usual three.

“The bicuspid anatomy is actually the most common congenital malformation,” said Pieter Kappetein, Medtronic vice president and chief medical officer of the Heart Valve Therapies business in an investor and analyst briefing following the ACC presentation. “It results in that more than 60% of patients who are at low risk and who have an aortic stenosis have a bicuspid valve.”

These patients have been excluded from previous TAVR studies because they “generally have multiple anatomic and technical concerns with TAVR procedures,” Ramlawi said. “These include a more asymmetric annulus, excessive calcification, and the presence of raphae (congenitally fused leaflets). In addition, BAVD patients, like all low-risk aortic stenosis patients, have excellent results with traditional surgical aortic valve replacement.”

Most study participants had Sievers bicuspid type 1 (91%), while 9% had a type 0 bicuspid.

“Interestingly, type 0 patients, who are traditionally more concerning for TAVR due to more difficult anatomy, performed just as well as the type 1 bicuspid patients with excellent hemodynamics and no residual moderate/severe aortic insufficiency,” Ramlawi noted.

The study demonstrated a 95.3% device success rate. No patients experienced annular rupture or aortic dissection.

In addition, “30-day mortality seen in this bicuspid TAVR study at 0.7% is on par or better than most trials assessing TAVR in the low-risk general population” with tricuspid valves, Ramlawi added. One patient died and one suffered a disabling stroke.

The Evolut TAVR platform includes the Evolut R, Evolut Pro, and Evolut Pro+ TAVR Systems. The systems are currently approved for use in patients with symptomatic severe aortic stenosis, ranging from low-risk to extreme, and for intermediate-risk patients with BAVD.

In the study, 57% of patients received an Evolut Pro valve and 43% received an Evolut R valve.

Dublin-based Medtronic plans to submit the results of the study to the U,S, FDA for revised TAVR labeling, Kappentein said.

Market implications

Evolut technology “is well positioned as the valve of choice for low-risk patients,” said Nina Goodheart, Medtronic vice president and general manager of Diagnostics and Monitoring in the briefing. “All of our studies to date continue to show superior hemodynamics compared to surgery and to other valve options, which we think is critical to lower-risk and potentially younger patients.”

Goodheart estimated the size of the TAVR market to be about $5 billion and she anticipated that about 800 accounts in the U.S. would be doing the procedure.

The results of recent trials “has really created a significant paradigm shift in terms of device selection in these lower-risk and potentially younger patients,” Goodheart noted. “With low risk, the criteria for device selection has shifted from really just thinking about risk characterization to moving more towards age, towards anatomy and towards activity level. And in this population, it's becoming clearer that hemodynamics, patient prosthesis mismatch, the ability to treat bicuspid valves, and valve durability become much more important.”

With the move away from clinical risk as the primary factor, heart teams may give increasing weight toward patient-specific data that may favor TAVR, such as patient frailty, rehabilitation potential, and structural issues, Ramlawi said.

Medtronic noted that its TAVR business had shown positive momentum in its current fiscal quarter, with a significant increase in implant rates. In recent weeks, however, COVID-19 has resulted in delayed procedures around the world. Elective surgeries have been particularly hard hit, with concomitant impact on Medtronic revenues, said Michael Coyle, Medtronic executive vice president and group president of the Cardia and Vascular Group in the briefing.

On the upside, the company reported that procedures had begun picking up again in China. Elsewhere, the delays have built over the last month and the company expects the Q4 numbers to reflect their significant negative impact on the top line.