PARTNER: TAVR Compares Well Even With Minimally Invasive Surgery
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While cohort A of the PARTNER trial established transcatheter aortic valve replacement (TAVR) as noninferior to surgical AVR for high-risk patients with severe aortic stenosis, there have been few formal comparisons between the transcatheter technique and minimally invasive surgery. In a new subanalysis presented Monday, January 30, 2011, at the Society of Thoracic Surgeons (STS) annual meeting in Ft. Lauderdale, FL, researchers showed that TAVR is just as effective as the alternative surgical technique, and perhaps safer in the short term.
For the PARTNER (Placement of AoRTic TraNscathetER valve) trial’s cohort A, researchers randomized 699 patients at high surgical risk to receive TAVR (via transapical or transfemoral access) or surgery at 25 centers in the United States, Canada, and Germany.
In the new posthoc subanalysis, investigators led by Vinod H. Thourani, MD, of Emory University School of Medicine (Atlanta, GA), compared 341 TAVR patients with patients receiving either full-sternotomy surgery (n = 250) or minimally invasive surgery (n = 49), which uses either a mini-thoracotomy or a partial sternotomy to access the heart.
Early Safety Signal with Mini-Surgery
Mean age (about 84 years) and STS predicted mortality risk (about 11%) were equivalent across groups. At 30 days, mortality was equivalent between TAVR and full-sternotomy surgery, but minimally invasive surgery showed a higher death rate, although the difference was not statistically significant. Major vascular complications, meanwhile, were higher with TAVR, while other endpoints such as rehospitalization and stroke were equivalent between all groups.
Table 1. Thirty-Day Endpoints
|
TAVR |
Minimally Invasive Surgery |
Full-Sternotomy Surgery |
Mortality |
5.2% |
14.3%a |
6.8% |
Rehospitalization |
5.4% |
6.7% |
5.2% |
Stroke |
4.4% |
4.1% |
2.3% |
Major Vascular Complications |
11.1% |
2.0%b |
4.2%c |
a P = 0.08 vs. TAVR.
b P = 0.0006 vs. TAVR.
c P = 0.001 vs. TAVR.
On multivariable analysis that adjusted for STS score, full-sternotomy surgery was not associated with increased mortality at 30 days compared with TAVR (adjusted OR 1.33; 95% CI 0.68-2.60; P = 0.41), but minimally invasive surgery was (adjusted OR 3.02; 95% CI 1.19-7.65; P = 0.02).
At 1 year, however, neither full-sternotomy surgery (adjusted OR 1.06; 95% CI 0.73-1.54; P = 0.40) nor minimally invasive surgery (adjusted OR 1.17; 95% CI 0.59-2.32; P = 0.65) was associated with increased mortality compared with TAVR.
Dr. Thourani noted that, overall, both TAVR and surgical AVR provide excellent results in high-risk patients, but “early mortality is significantly higher in those patients undergoing [minimally invasive] AVR vs. TAVR.”
Despite this, “one-year mortality was not significantly different among groups,” Dr. Thourani said, adding that “in this high-risk patient population, careful preoperative consideration for operative strategy should be performed.
“Unfortunately, [the analysis is] underpowered, so we can’t make any strong conclusions and it’s very difficult to tease out exactly why the mini-surgery patients did worse at 30 days,” Dr. Thourani told TCTMD in a telephone interview. “What this study shows is that we need to do more investigation on mini vs. full sternotomy. We’ve uncovered that something is going on, [and] what it is deserves a randomized study to look at that further.”
Surgeons Differ Regarding Pros and Cons of Procedure
He explained that surgeons have differing views on the merits of minimally invasive heart surgery. Proponents point to decreased release of inflammatory mediators and less trauma on the lungs since there is no full sternotomy. “Since you don’t open the entire chest, the lungs take less of a hit,” Dr. Thourani said.
However, detractors claim they are unable to adequately cool the heart with ice, contributing to decreased myocardial protection, and have to operate with lower visibility because of the smaller incisions. “So it takes longer because they can’t see as well, increasing cardiopulmonary bypass time,” Dr. Thourani said. “It’s very dependent on the surgeon. We’ve done many of these procedures in healthier patients. The question is, what do we do in these high-risk cases?”
Theodore A. Bass, MD, of the University of Florida College of Medicine (Jacksonville, FL), agreed that the early safety signal with minimally invasive surgery is “a little concerning,” adding that “it’s appropriate that this be looked into a little more carefully.”
‘Do What You’re Good At’
Nevertheless, “at 1 year, they’re still equal,” he said. “That’s what happened with PARTNER [cohort] A. There are certain advantages with surgical or endovascular-based therapy, and a lot of the discrepancies equal out after a year, so [this new finding] makes sense.”
Dr. Bass noted that only a minority of patients in the study were treated via minimally invasive surgery, and the choice to use the technique is primarily driven by training and operator experience. “It’s done only in certain centers, so it’s not a widespread practice,” he said, adding that a key message from the study in terms of choosing a particular technique is to “do what you’re good at and what you do often. If you’re not doing many of your aortic valves via a minimally invasive approach, maybe the message is either get more training or stick with what your quality numbers are.”
“That’s exactly right,” Dr. Thourani said. “You don’t want to do anything new or inventive on these types of high-risk patients.”
Study Details
Prior CABG was significantly more common in the TAVR group compared with the minimally invasive surgery group, but less common compared with the full-sternotomy group. Ejection fraction was similar across all groups (range 53%-57%). In the TAVR group, more patients received the transfemoral approach compared with the transapical approach.
Source:
Thourani VH. Short- and mid-term outcomes in patients undergoing transcatheter versus minimally-invasive or full sternotomy aortic valve replacement: Results from a U.S. multi-institutional trial. Paper presented at: 48th Society of Thoracic Surgeons Annual Meeting; January 30, 2012; Ft. Lauderdale, FL.
Disclosures:
- Dr. Thourani reports serving on the speakers bureau/receiving honoraria from Edwards Lifesciences and Sorin Medical, and serving as a consultant/advisory board member to St. Jude Medical.
- Dr. Bass reports no relevant conflicts of interest.
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