Transcatheter aortic valve implants once again took the spotlight at the annual meeting of the American College of Cardiology, with a spate of studies both confirming the long-term benefits of the replacement heart valves and showing that newer TAVI versions are even better.

The results position TAVI to become the standard of care for aortic valve stenosis, according to Leerink Partners analysts Danielle Antalffy.

“The key take-home message from ACC was that TAVI is rapidly advancing toward standard of care in not just high-risk and inoperable patients but also in the much larger intermediate-risk patient population – likely to support double-digit TAVI market growth for the foreseeable future," Antalffy wrote this morning in a note to investors.

Final 5-year data for Edwards Lifesciences‘ (NYSE:EW) market-leading Sapien device from the Partner trial, presented over the weekend at the ACC meeting in San Diego, showed its benefits and durability in both inoperable and high-risk groups.

After 5 years the inoperable cohort showed an all-cause mortality rate of 71.8%, compared with 93.6% for the TAVI control group, patients treated with open heart surgery. For the high-risk TAVI group, the 5-year mortality rate was 67.8%, compared with 62.4% for the surgical control arm.

"It’s remarkable that this 5-year data report continues to show equivalency between what was then a brand-new procedure with a 1st-generation TAVI device and the gold standard of surgery, which has been honed over 50 years of experience," Dr. Michael Mack, who presented the results at ACC, said in prepared remarks. "Just as we observed in the 5-year report from the Partner trial on outcomes in inoperable patients treated with Sapien, the high-risk patients also had durable valve performance. These data show that TAVI is an effective treatment for these patients."

Medtronic’s competing CoreValve device also did well, with 2-year results showing that TAVI patients fared better than the t surgical valve replacement control group. The data, also presented at ACC, not only showed that results seen at 1 year were sustained a year later, but that there were greater differences favoring CoreValve over open heart surgery.

The rate of all-cause mortality or major stroke at 2 years was 24.2% for CoreValve, versus 32.5% for surgery, a greater difference than 1-year rates of 16.2% and 22.5%. The difference in all-cause mortality alone and for all strokes in the trial of 750 high-risk patients also favored TAVI by a wider margin at 2 years. For all strokes, the rate after two years was 10.9% for CoreValve versus 16.6% for surgery.

"This data is strong enough that it should change our guidelines in the increased risk surgical population where TAVR is not just an alternative to surgery, but it should be the preferred option," said lead investigator Dr. Michael Reardon, noting that It had been believed that TAVI would have a hard time competing with surgical results.

"We did really good surgery and at 2 years there was a survival advantage [for TAVI] that was highly statistically significant," Reardon said. "When you look at the way the field is going, for me as a cardiac surgeon it may not be that great, but for our patients it’s really groundbreaking."

Next-generation devices even better

Results for the 3rd-generation Sapien 3 from Edwards showed very low mortality and stroke rates at 30 days, with a 2.2% mortality rate in high-risk patients and a 1.1% death rate among intermediate-risk patients. The rate for all strokes at 30 days was 1.5% for high-risk patients and 2.6% for the intermediate-risk group. The disabling stroke rates were 0.86% and 1%.

"The numbers that we’re seeing are truly phenomenal," said co-lead investigator Dr. Susheel Kodali. "This is a sick population."

The results demonstrated a clear improvement over those seen in prior studies of two earlier Sapien iterations and compared favorably to historical complication expectations for surgical valve replacement, Kodali said. The mortality rate for high-risk patients in a trial of the original Sapien was more than 5%, he explained.

The Sapien 3 features a smaller catheter to deliver the valve to the heart than its predecessors, and an improved design aimed at minimizing valve leakage. It has been in use in Europe for high risk and inoperable patients since early 2014. Edwards is hoping to gain U.S. approval in early 2016.

The study involved 583 high-risk and 1,076 intermediate-risk patients with an average age of about 82.

The combined rate of moderate or severe valve leakage was under 4%. "In terms of reducing significant perivalvular leak, the rates are extremely low," said Kodali, director of the Heart Valve Center at Columbia New York Presbyterian Hospital.

In coming years, Kodali said, he envisions TAVI will no longer be viewed as a secondary option. "The conversation will be who’s going to be getting surgery in the era of TAVI."

Thirty-day results for Medtronic’s next-generation TAVI offering, the CoreValve Evolut R, were also extremely promising. The 60-patient Evolut R trial showed no incidents of all-cause mortality or stroke in a high- and extreme-risk patients, Medtronic said.

"Initial clinical experience with the Evolut R system is remarkable and ushers in a new era of TAVI technology that provides increased confidence with recapturability, excellent procedural results, and impressive clinical outcomes," study investigator Dr. Ian Meredith said in prepared remarks. "The 14 French-equivalent delivery system allowed transfemoral access for most patients and the recapturable technology enabled implanters to optimize valve placement for improved annular sealing and reduced conduction disturbances without compromise on mortality or stroke."

Material from Reuters was used in this report.