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PARTNER 2: TAVR noninferior to surgery in intermediate-risk patients
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CHICAGO — In intermediate-risk patients, transcatheter aortic valve replacement was noninferior to surgical valve replacement for death or disabling stroke, according to new data from the PARTNER 2 trial.
Researchers assigned 2,032 patients with severe aortic stenosis and intermediate risk for surgery to undergo TAVR with a balloon-expandable system (Sapien XT, Edwards Lifesciences) or surgical AVR. Patients were also stratified into two cohorts based on clinical and imaging findings: a transfemoral-access cohort (76.3%) and a transthoracic-access cohort (23.7%).
During a press conference at the American College of Cardiology Scientific Session, Craig R. Smith, MD, Chief of Surgery at NewYork-Presbyterian/Columbia University Medical Center, said the rate of the primary endpoint — all-cause mortality or disabling stroke at 2 years — was similar in both groups. Disabling stroke was defined as modified Rankin Scale score ≥ 2 at 90 days after stroke.
Craig R. Smith
In the intention-to-treat population, the primary endpoint occurred in 19.3% of the TAVR group vs. 21.1% of the surgery group (HR = 0.89; 95% CI, 0.73-1.09; P for noninferiority = .001). In the as-treated population, the primary endpoint occurred in 18.9% of the TAVR group vs. 21% of the surgery group (HR = 0.87; 95% CI, 0.71-1.07; P for noninferiority < .001), Smith and colleagues reported.
In the transfemoral-access cohort, TAVR was associated with reduced risk for the primary outcome compared with surgery (HR = 0.79; 95% CI, 0.62-1). Smith noted that there was no difference in the transthoracic-access cohort.
The researchers found that the TAVR group had larger aortic valve areas and lower rates of acute kidney injury, severe bleeding and new-onset atrial fibrillation, while the surgery group had lower rates of major vascular complications and paravalvular aortic regurgitation.
“Based on all previous experience with TAVR, we know that TAVR valves leak more than surgical valves, which is no surprise to anyone,” Smith, Johnson & Johnson Distinguished Professor, Valentine Mott Professor of Surgery and chair of the department of surgery at Columbia University and surgeon-in-chief at Seymour Milstein Family Heart Hospital and New York-Presbyterian Hospital/Columbia University Medical Center, said during the press conference.
“One of the unanswered questions is: How important is that? We know now from this report that in medium-risk patients, at 2 years, there was indeed significantly more paravalvular regurgitation with TAVR valves than surgery, but in only 8% was it moderate or greater. Most was mild or trace. Compared with previous experiences reported with a balloon-expandable valve, this is an improvement in the rate of paravalvular regurgitation. If you are in the 8% that is moderate or severe [paravalvular regurgitation], there is indeed impact on mortality, but in the mild group, it no longer appears to affect mortality, at least in this cohort.”
Those who had no or trace paravalvular regurgitation had an all-cause mortality rate of 14.1% at 2 years, those with mild paravalvular regurgitation had a rate of 13.5% (log-rank P = .82) and those with moderate or severe had a rate of 34% (log-rank P < .001), Smith said.
In an editorial accompanying the study in The New England Journal of Medicine, Neil E. Moat, MBBS, from the Transcatheter Valve Programme, Royal Brompton Hospital, London, noted that the results “seem to confirm that TAVR is the treatment of choice for most patients with aortic stenosis who are at high risk for early death and major complications from conventional surgery, particularly if the patient has clinical and vascular features such that he or she can be treated by a transfemoral (or perhaps nontransthoracic) approach.” – by Erik Swain
References:
Leon MB, et al. Joint ACC/JACC Late-Breaking Clinical Trials. Presented at: American College of Cardiology Scientific Session; April 2-4, 2016; Chicago.
Leon MB, et al. N Engl J Med. 2016;doi:10.1056/NEJMoa1514616.
Moat NE. N Engl J Med. 2016;doi:10.1056/NEJMe1603473.
Disclosure: Smith reports receiving reimbursement for travel and trial-related expenses from Edwards Lifesciences. Please see the full study for a list of the other researchers’ relevant financial disclosures. Moat reports receiving personal fees from Abbott, Direct Flow Medical, Edwards Lifesciences, Medtronic, Mitralign and Tendyne.
Perspective
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Michael Rinaldi, MD
This trial was a well-conducted study at excellent centers, and was well thought-out. It found that TAVR seems to be as good as conventional surgery for all the outcomes in an intermediate-risk population. The complication rates were excellent in the TAVR arm. Stroke and death were equal in the two arms, and in the subset of patients with transfemoral access, which is the easier way to get a transcatheter valve done, patients statistically did better with TAVR than surgery. There can be no criticisms of the surgical techniques. Society of Thoracic Surgeons Predicted Rate of Mortality was 5%, but the observed mortality was only 3%, even in the surgical arm. The study had excellent surgery and excellent TAVR, and TAVR looks like a reasonable alternative to conventional surgery. That doesn’t mean that surgery is bad, just that TAVR is complementary. Hopefully, this will open up options for patients who are not perfect surgical candidates, but not terrible ones either.
The major implication is that TAVR has really caught on. At this point, the technique has advanced even from when this trial was conducted. The Sapien XT device, used in this trial, is a good device and better than the original Sapien device. But the new Sapien 3 device (Edwards Lifesciences) is even better, with a skirt that reduces paravalvular leak and a smaller profile to reduce vascular complications. In most centers, even the surgeons believe that TAVR is the best therapy for these patients. There had already been a lot of creep toward using TAVR in the intermediate-risk population. A lot of patients who are currently being called high-risk by surgeons probably would have qualified for this trial.
There were concerns that TAVR is associated with a higher paravalvular leak rate. There were slightly higher, but not terrible, paravalvular leak rates with the Sapien XT device. Interestingly, only patients with moderate or severe paravalvular leak had worse outcomes. Mild paravalvular leak was not associated with poorer outcomes. With the Sapien 3 device, we’re seeing almost no moderate or severe aortic insufficiency, just mild, which this study suggests is not important. There are also concerns about pacemaker rates being higher with TAVR. In this study, the pacemaker rates were slightly higher in the TAVR group, but not by a lot, approximately 2%. I find that reassuring, and it is important as we move the device to younger patients, in whom the implications of pacemakers are not insignificant. This is important as there remains concern that pacemaker rates are higher with TAVR, and these findings put that concern into question.
It is also important to note that in PARTNER 2, the length of stay was shorter with TAVR and complications such as major life threatening bleeding, kidney injury and new onset of atrial fibrillation were lower with TAVR than surgical AVR. TAVR appears in moderate risk patients to have a quicker recovery and lower risk for certain important complications.
I believe this will lead to FDA approval and Medicare reimbursement for this indication. The TAVR market share is approximately 30%, and I think after this study it will move toward 50%.
The PARTNER 3 trial of TAVR in low-risk patients is about to commence, as is a similar study with the CoreValve device (Medtronic), so the field is moving in the direction of TAVR.
This is a win for TAVR and patients. It does not mean that surgical valve replacement is going to go away, but it opens more options for a larger number of patients.
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