NEW ORLEANS – Transcatheter aortic valve replacement was associated with the same survival rates at 1 year as was conventional surgery in older, high-risk patients with severe, symptomatic aortic stenosis in the PARTNER trial.
All-cause mortality at 30 days favored transcatheter aortic valve replacement (TAVR) at 3.4%, compared with 6.5% for open surgery, and was similar at 1 year (24% and 27%, respectively). The difference at 1 year reached the trial’s prespecified noninferiority margin with a P value of .001.
Dr. Craig B. Smith
"We already learned from the previous cohort that TAVR is the standard of care for patients who can’t tolerate surgery. So this [finding] opens up a new set of patients who may very well benefit as much with TAVR as with the gold standard surgery," coprincipal investigator Dr. Craig B. Smith said at the annual meeting of the American College of Cardiology.
The stroke rate with TAVR in the industry-sponsored PARTNER (Placement of Aortic Transcatheter Valve) trial, however, was associated with a stroke rate that was twice the rate observed with surgery.
Stroke plus transient ischemic attack (TIA) rates were significantly more frequent with TAVR than surgery at both 30 days (5.5% vs. 2.4%) and 1 year (8.3% vs. 4.3%). When only major strokes were compared, the difference was not significant between TAVR and surgery at 30 days (3.8% vs. 2.1%) or 1 year (5.1% vs. 2.4%), said Dr. Smith, chief of cardiothoracic surgery at New York–Presbyterian Hospital/Columbia University Medical Center in New York City.
Notably, patients who underwent conventional surgery were significantly more likely than TAVR patients to experience major bleeding at 30 days (19.5% vs. 9.3%) and 1 year (26% vs. 15%), as well as new atrial fibrillation at both 30 days (16% vs. 8.6%) and 1 year (17% vs. 12%).
Echocardiographic findings indicated a small hemodynamic benefit with TAVR vs. surgery at 1 year, but significantly increased paravalvular aortic regurgitation at 30 days, 6 months, and 1 year.
"TAVR and AVR [aortic valve replacement] are both acceptable therapies in these high-risk patients; differing periprocedural hazards should influence case-based decision making," Dr. Smith said.
Dr. David Moliterno, chair of the intervention program (i2 Summit) at the meeting, told reporters that they were witnessing history in the making.
"This will probably be seen as one of the biggest steps in cardiovascular medicine, as far as intervention is concerned, potentially in our lifetime," said Dr. Moliterno, chief of cardiovascular medicine at the University of Kentucky, Lexington. "If we look back to balloon angioplasty, the advent of stents and drug-eluting stents, ... this will be seen as the next major turning point."
Last year, the PARTNER trial investigators reported a 20% survival benefit at 1 year in a separate cohort of 358 inoperable patients with severe aortic stenosis who underwent transfemoral TAVR vs. standard therapy, including balloon aortic valvuloplasty (N. Engl. J. Med. 2010;363:1597-607). TAVR was associated with significantly more major vascular complications (16% vs. 1%) and a higher incidence of major strokes (5% vs. 1%).
The current portion of PARTNER randomly assigned 699 patients at 26 centers to surgery or TAVR, using the transfemoral approach in 492 patients and the transapical approach in 207.
Severe stenosis was defined as an aortic valve area of less than 0.8 cm2 and mean aortic valve gradient of more than 40 mm Hg or a peak aortic jet velocity of more than 4.0 m/second. The patients had a New York Heart Association heart failure class II or greater, and had a predicted risk of operative mortality of at least 15% as determined by the site surgeon and cardiologist, coupled with a Society of Thoracic Surgery score of at least 10.
Their mean age was 83 years, and 94% were NYHA class III or IV. In all, 42 patients were not treated as assigned, Dr. Smith said.
All-cause mortality at 1 year was similar for the transfemoral TAVR subgroup, at 22.2% and 26.4% for surgery, as well as for the transapical TAVR subgroup (29% vs. 28%, respectively).
A preliminary subgroup analysis suggests that there may be a possible benefit with TAVR in women and patients without prior coronary artery bypass surgery, but Dr. Smith said that those results should be interpreted cautiously.
Overall, the TAVR mortality of 3.4% at 30-days was the lowest reported in any series, despite the use of an early-generation device and limited previous operator experience, he said, noting that nine of the participating centers had never performed TAVR before the trial.
Symptom improvement, including NYHA class and 6-minute walk distance, favored TAVR at 30 days and was similar to conventional surgery at 1 year, he said.