Results from trials of both Medtronic‘s (NYSE:MDT) and Edwards Lifesciences‘ (NYSE:EW) transcatheter aortic valve replacement systems exploring their use in low-risk patients indicated that the devices were as safe as open surgery, paving the way for possible new indications for TAVR technology.
Data from the trials were presented over the weekend at the American College of Cardiology 68th Annual Scientific Session 2019 in New Orleans and simultaneously published in the New England Journal of Medicine.
Currently, TAVR devices are only approved by the FDA for treating severe aortic valve stenosis in patients at intermediate and high risk for death and complications associated with surgery.
The results, both from trials exploring use of TAVR devices in low-risk patients, earned a standing ovation for presenters at the conference, according to a Medscape report.
In the Medtronic-sponsored Evolut Low Risk study, researchers reported that the use of its self-expanding TAVR system, when compared to open-heart surgery for valve replacements, had a similar rate of disabling stroke or death from any cause at two years at 5.3% versus 6.7%, respectively.
“We now have a minimally invasive procedure that is as good as or better than surgery, while at the same time allowing most patients to be out of the hospital within a few days and be back to their normal activities within a week, and that’s pretty important,” study senior author Dr. Michael Reardon of Houston Methodist Hospital said in a press release.
In the trial, study investigators recruited 1,468 patients with severe, symptomatic aortic stenosis who were deemed to be at low risk of surgery. Patients either received TAVR treatments with one of three Medtronic self-expanding devices, the CoreValve, Evolut R and Evolut Pro, or underwent surgical aortic valve replacement with biopsothetic surgical valves.
The majority of patients in the trial, 74.1%, received Fridley, Minn.-based Medtronic’s Evolut R, while the third-generation Evolut Pro was used in 22.3% and the CoreValve was used in 3.6% of patients, researchers report.
Study researchers said that groups were well-matched in terms of baseline characteristics, with a 2-to-1 ratio of men to women.
At 30 days, TAVR was shown to be statistically superior to SAVR, with a 0.8% rate of disabling stroke or all-cause mortality versus 2.6%, respectively. Rates of death at one month were not statistically different between TAVR and SAVR at 1.3% and 0.5%, respectively, according to the study.
TAVR maintained its superiority to open heart surgery for major stroke at one year, at 0.8% for TAVR patients versus 2.4% in SAVR patients. All-cause mortality rates were similar at 2.4% for TAVR versus 3% for SAVR, while hospitalization and heart failure rates were are 3.2% for TAVR versus a higher 6.5% for SAVR patients.
Quality of life assessments using the Kansas City Cardiomyopathy Questionnaire were higher for TAVR patients than SAVR at 20 versus 9.1 at one month post-procedure, with scores evening out at one year to 22.2 for TAVR and 20.9 for SAVR patients, according to the study.
“TAVR beat surgery at 30 days for mortality or disabling stroke, quality of life and time in the hospital. In other words, you’re more likely to be alive without a disabling stroke, get out of the hospital sooner— in half the time—and have a better quality of life one month after getting a new valve. The mean age of patients in this study was 74, so while this is still not a young group of patients, many of them are very active and whether it be in their professional or social lives, getting back to full range of daily activities is very important to them. At one year, patients with TAVR were more likely than surgery patients to be alive, without a disabling stroke and without a hospital admission for heart failure,” Reardon said in a prepared statement.
Data from echocardiograms indicated that TAVR valves may work better than SAVR valves, with an orifice measurement of 2.2 cm2 vs 2.0 cm2, respectively, and lower mean gradients than surgery at all time points in the trial, according to study data.
Similar to earlier studies, TAVR patients had had more pacemakers and moderate to severe paravalvular leakage, more vascular injuries including dissection, cardiac perforation and access site injuries. SAVR patients reported more cases of atrial fibrillation, transfusions and acute kidney injury, according to the report.
Researchers in the trial plan to follow patients out to 10 years, exploring long-term data as well as cost-effectiveness. Study investigators said that the study was limited by short follow-up time, and that the trial excluded patients with bicuspid aortic valves and those with anatomic incompatibilities.
“We’ve now looked at a broad risk spectrum of patients—those at high, intermediate and low surgical risk—and these series of trials have shown that TAVR is better than or as good as surgery in terms of disabling strokes and deaths from all causes. When we look at secondary outcomes of quality of life and functional recovery, these seem to favor TAVR at this point. Given this data, it now seems reasonable to consider moving TAVR in low risk patients to a class I guideline indication on par with surgery for patients with severe aortic stenosis,” Reardon said in prepared remarks.
In a separate presentation on the same day, Edwards Lifesciences touted that data from its PARTNER 3 study of its Sapien 3 TAVR system indicated a reduction in death, stroke and rehospitalization of 46% at one year.
A total of 1,000 patients with severe aortic stenosis deemed at low risk for surgery were recruited for the PARTNER 3 trial, the Irvine, Calif.-based company said. The group was younger, at 73 years average, with fewer co-morbid conditions and fewer symptoms than previous PARTNER trials, with a similar two-to-one ratio of men to women.
The primary endpoint of the trial was a combined rate of all-cause death, any stroke and re-hospitalizations at one-year post procedure, Edwards said.
Results from the trial indicated a 1% mortality rate for TAVR patients versus 2.5% in SAVR patients, with a 1.2% stroke risk for TAVR patients versus a higher 3.1% rate for SAVR patients. SAVR patients were also more likely to be rehospitalized, at an 11% rate, versus only 7.3% for TAVR patients.
“This is a landmark study because it involves 80 percent of the people who are currently being treated with surgery for aortic stenosis. Our hope was that TAVR would be non-inferior or comparable to surgery, and we were surprised to find an almost 50 percent reduction in the primary endpoint, from 15.1% in the surgical group to 8.5% with TAVR. This is beyond anything we could have expected, mostly because surgery is so good in treating aortic stenosis in these low risk patients. Taken by themselves, each component of the primary endpoint also favored TAVR, which is confirmatory evidence of the outcome,” lead study author Dr. Martin Leon of the New York-Presbyterian/Columbia University Irving Medical Center said in a press release.
Evaluation of secondary endpoints indicated that hospital stay length was reduced from seven to three days for TAVR patients, and that TAVR patients had more rapid 30-day functional recovery based on six-minute walk tests and quality of life measurements.
Post-operative or new onset atrial fibrillation was reported in approximately 40% of SAVR patients, compared to only 5% in TAVR patients. Major vascular complications were also similar between groups, Edwards said.
Patients in the TAVR arm were more likely to need new permanent pacemakers, at 6.5% for TAVR patients versus 4% for SAVR patients, while rates of moderate to severe paravalvular leaks were similar between groups.
“Surgery eventually catches up to TAVR in terms of functional recovery and quality of life, but it takes several months. TAVR is a less invasive procedure, so we expect an earlier return to normal daily activities compared with surgery. There has also been an evolution of TAVR technology, increased operator experience and enhanced procedural techniques, all of which combine to lower complications after TAVR especially in the lowest risk patients,” Leon said in a prepared statement.
Researchers in the trial said it was limited by its breadth and said that longer-term follow-ups would be needed to explore the viability of TAVR devices. Study investigators added that they plan to follow patients in the trial out to ten years.
“The results of this trial in low risk patients indicates that the choice of TAVR versus surgery for severe aortic stenosis should be independent of surgical risk profile assessments. The combined rate of death and disabling stroke at one year was only 1 percent with TAVR, which was an unexpectedly favorable outcome. Based on these findings, the choice of TAVR versus surgery should be a shared decision-making process that respects patient preferences and considers some of the knowledge gaps, especially in treating young patients,” Leon said in prepared remarks.
