TAVR: More procedural success with balloon-expandable valves

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Head-to-head comparison fills a void

The lack of a head-to-head comparison in a multicenter, randomized clinical trial has made it difficult to choose the appropriate device for a given patient. The report by Abdel-Wahab et al. on the CHOICE trial, a randomized clinical trial comparing balloon-expandable and self-expanding valves, fills this void, albeit partially. The authors conducted a robust randomized trial involving 241 patients at five centers and experienced investigators capable of implanting either valve with expertise.

The balloon-expandable valve implantation resulted in a higher device success than did the self-expanding valve, with device success of 95.9% (116 of 121 patients) in the balloon-expandable valve group and 77.5% (93 of 120 patients) in the self-expanding valve group. This result is important but should not be interpreted as a surrogate for long-term outcomes, such as death, stroke, and quality of life. In this relatively small study, there was no difference in 30-day cardiovascular mortality (4.3% in the self-expanding valve group and 4.1% in the balloon-expandable valve group), Dr. Murat Tuzcu and Dr. Kapadia wrote in an accompanying editorial in JAMA (2014 March 30 [doi:10.1001/jama.2014.3317]).

Although the two study groups were, for the most part well balanced, more women were in the self-expanding group than in the balloon-expandable group. In the PARTNER trial, women had greater benefit from TAVR with balloon-expandable valve, compared with men. In the CHOICE trial, sex imbalance may have introduced some bias that could not be addressed because of the small size of the study. In addition, paravalvular regurgitation and the need for a second valve were significantly less for balloon-expandable valve, whereas stroke and coronary occlusion were numerically, although not statistically, higher for the balloon-expandable valve. These and other points have been discussed extensively in the literature, as they are critical in deciding which valve to use in a given patient.

Dr. E. Murat Tuzcu and Dr. Samir R. Kapadia are both at the Heart and Vascular Institute, department of cardiology, Cleveland Clinic.



Patients with high-risk aortic stenosis undergoing transfemoral transcatheter aortic valve replacement saw better results with balloon-expandable valve prostheses, compared with self-expanding valve prostheses, according to results from the first multicenter, randomized trial comparing the two types of devices directly.

For their research, presented at the annual meeting of the American College of Cardiology, Dr. Mohamed Abdel-Wahab of the Segeberger Kliniken in Bad Segeberg, Germany, and his associates randomized 241 patients with severe aortic stenosis to either a balloon-expandable valve (n = 121; 43% men) or a self-expanding valve (n = 120; 28.3% men). Patients were recruited from five centers in Germany between March 2012 and December 2013, and followed up for 30 days post procedure.

The trial’s main endpoint was device success – a 4-point composite, incorporating correct device positioning, performance of the valve without more than mild regurgitation, successful vascular access and deployment of the device and retrieval of the delivery system, and only one valve implanted.

Secondary endpoints included cardiovascular mortality, need for new pacemaker placement post procedure, major stroke and other vascular events, and a combined safety endpoint of all-cause mortality, major stroke, bleeding, kidney injury, myocardial infarction, major vascular complications, and repeat procedure for valve-related dysfunction, they said in a report on their research that was simultaneously published in JAMA (2014 March 30 [doi:10.1001/jama.2014.3316]).

Device success was seen as markedly higher among patients receiving the balloon-expandable valves (95.9% of patients, compared with 77.5%; relative risk 1.24; 95% confidence interval, 1.12-1.37; P less than .001), thanks mainly to less incidence of moderate to severe aortic regurgitation after valve placement (4.1% vs. 18.3%; RR, 0.23; 95% CI, 0.09-0.58; P less than .001).

Observational studies have found widely differing outcomes in aortic regurgitation associated with the different devices, due in part to "challenges in identification and quantification of aortic regurgitation after TAVR [transcatheter aortic valve replacement], but also to the observational and nonrandomized nature of all reported comparisons," Dr. Abdel-Wahab and his colleagues wrote. This study used angiographic, echocardiographic, and hemodynamic assessments of aortic regurgitation following TAVR.

At 30 days post procedure, new pacemakers had been placed half as frequently in the balloon-expandable valve group (17.3% vs. 37.6%, P = .001). Altogether five patients were rehospitalized for heart failure in the self-expanding valve group, compared with none in the balloon-expandable group.

Neither 30-day cardiovascular mortality nor vascular nor bleeding complications were significantly different between the two groups. In the balloon-expandable group, 30-day mortality was 4.1%, compared with 4.3% for the self-expanding group. The combined safety end point occurred in 18.2% of those in the balloon-expandable valve group and 23.1% of the self-expanding group (RR, 0.79; 95% CI, 0.48-1.30; P = .42).

However, patients in the balloon-expandable arm saw higher numerical incidence of stroke. Stroke was seen in seven patients (three major and four minor strokes), compared with three (all major strokes) in the self-expanding valve group.

The investigators described the use of core laboratory–adjudicated angiography and the lack of an echocardiographic core laboratory as potential limitations of their study. Long-term follow-up was needed, they said, to "determine whether differences in device success will translate into a clinically relevant overall benefit for the balloon-expandable valve."

The study was sponsored by Dr. Abdel-Wahab’s institution. Dr. Abdel-Wahab disclosed support from Medtronic, Edwards Lifesciences, and Boston Scientific. Four of his 11 coauthors disclosed support from Abbott Vascular, Terumo Lilly/Daiichi Sankyo, Biotronik, Edwards Lifesciences, Medtronic, and/or Boston Scientific.

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