An analysis of 28 multicenter registries and nine randomized trials found that transcatheter aortic valve replacement (TAVR) studies tended to underestimate the incidence of permanent pacemaker implantations because they do not include patients who had permanent pacemakers before undergoing TAVR.

Lead researcher Josep Rodés-Cabau, MD, of the Quebec Heart and Lung Institute at Laval University in Canada, and colleagues published their results online in the Journal of the American College of Cardiology on Nov. 21.

The researchers included large multicenter registries and randomized trials that evaluated the Sapien and Sapien XT balloon-expandable valve systems from Edwards Lifesciences and the CoreValve self-expanding valve system from Medtronic in patients with native severe aortic stenosis.

They estimated the incidence of new permanent pacemaker implantations by excluding patients with permanent pacemakers before undergoing TAVR as well as patients who died within 30 days of undergoing TAVR. They also determined an estimated minimal incidence of new permanent pacemaker implantation by assuming that patients who died after the procedures had prior pacemakers. In addition, they obtained an estimated maximal incidence of new permanent pacemaker implantations by assuming that none of the patients who died had pacemakers.

For the nine studies that enrolled patients using both valve systems, the mean reported incidence of new permanent pacemaker implantation was 15 percent, while the mean estimated minimal incidence was 16.9 percent and the mean estimated maximal incidence was 18.2 percent.

For the 11 studies that evaluated the self-expanding valve system, the mean reported incidence of new permanent pacemaker implantation was 23.1 percent, while the mean estimated minimal incidence was 27.4 percent and the mean estimated maximal incidence was 29.9 percent.

For the 14 studies that evaluated the balloon-expandable valve systems, the mean reported incidence of new permanent pacemaker implantation was 6.8 percent, while the mean estimated minimal incidence was 7.8 percent and the mean estimated maximal incidence was 8.4 percent.

“Controversy still exists regarding the long-term impact of new [permanent pacemakers] post-TAVR, but the short- and long-term risks and morbidity associated with [permanent pacemakers] are well known,” the researchers wrote. “Therefore, it would be important to consider these results in future TAVR studies especially with the shift towards implanting newer generation devices within lower-risk patients. Also, these results should be taken into account when advising TAVR candidates without prior [permanent pacemakers] about the risks of the procedure.”