Findings from REPRISE III (The Repositionable Percutaneous Replacement of Stenotic Aortic Valve through Implantation of Lotus Valve System—Randomized Clinical Evaluation), as published in the Journal of the American Heart Association, present new insights around incidence and proposed predictors of pacemaker implantation and pacemaker dependency after TAVR.

Due to the proximity of the aortic annulus with the atrioventricular conduction system, replacement of the aortic valve often results in bundle branch block or high degree atrioventricular block and subsequent implantation of a permanent pacemaker. According to the paper, although long‐term pacemaker dependency rates of 27% to 68% following transcatheter aortic valve replacement (TAVR) have been reported, these studies have not systematically assessed pacemaker dependency using a consistent protocol‐driven algorithm. Further, despite the prevalence of these incidents, there remains a lack of data and consensus around guidelines for pacemaker implantation after TAVR.

“Despite the rapid adoption of TAVR for the treatment of aortic stenosis, the high frequency of conduction disturbances and subsequent requirement for permanent pacemaker remains a challenge,” said Robert C Stoler, MD, one of the paper’s authors. “Additional data could lend support to the safe continued expansion of this procedure to more populations.”

REPRISE III was the first large‐scale randomized comparison of two different TAVR platforms: the Lotus mechanically‐expanded valve and the CoreValve self‐expanding bioprosthesis. In evaluating cases from 912 patients with high/extreme surgical risk as well as severe, symptomatic aortic stenosis, the researchers:

• Captured incidence, timing, and predictors for pacemaker requirement to 30 days after TAVR
• Evaluated the proportion of patients who were pacemaker dependent after TAVR
• Outlined predictors and long‐term clinical impact of pacemaker dependency

Study Structure

In total, 912 patients with high/extreme surgical risk and severe, symptomatic aortic stenosis were randomized 2:1 between two transcatheter aortic valve replacement systems, Lotus and CoreValve with pre-existing pacemakers present in nearly 18% of patients receiving the Lotus valve and nearly 19% of patients receiving CoreValve.

Clinical outcomes were based on the Valve Academic Research Consortium end points and were analyzed between 30 days and 1 year to avoid bias stemming from patients not receiving a pacemaker because of early death. Additionally, echocardiograms were analyzed by an independent core lab and Kansas City Cardiomyopathy Quality of Life was used to assess health status.

Key Findings

By multivariable analysis, researchers outlined five key findings:

1. Patients with pre-existing pacemakers were at highest risk of death post-TAVR, however new pacemaker impanation was not associated with worse 1-year outcomes
2. Multivariate model predictors of new pacemaker implantation included baseline RBBB and depth of valve implantation
3. Pacemaker dependence was dynamic with 20- 25% of new pacemaker patients switching dependency status between 30 days and 1 year
4. Pacemaker dependent patients did not have worse clinical outcomes at 1 year compared with patients without a pacemaker.
5. Pacemaker dependency at both time points was predicted by baseline RBBB; depth of valve implantation and female sex predicted 30-day dependency whereas LVOT overstretch predicted 1-year dependency

Conclusion

Overall, the study demonstrated that implantation of a new pacemaker was not associated with adverse outcomes as compared with patients who did not receive a pacemaker and, in fact, was associated with numerically fewer adverse outcomes through 1 year.

Patients with a pacemaker before TAVR had a higher mortality rate compared with patients who never received a pacemaker. And overall, patients with a pre-existing permanent pacemaker were at the highest risk of adverse clinical outcomes.

No associations was identified between new pacemaker implantation and clinical outcomes. Most patients with a new pacemaker were not dependent at 1 year. Of those patients who were pacemaker dependent, there were no worse outcomes compared with either those patients without pacemaker dependency or patients without a pacemaker.

The two most consistent independent predictors of new pacemaker implantation, regardless of device used, were pre-existing right bundle branch block (RBBB), which is commonly associated with poorer clinical outcomes, and the depth of the valve implantation.

The authors also noted select factors that would require additional research, including:

• Certain complications and financial considerations related to the pacemaker itself
• Patient demographics as these data were primarily derived from higher risk populations
• The clinical consequences of new pacemaker implantation in lower risk patients

The full paper is available https://www.ahajournals.org/doi/10.1161/JAHA.119.012594.

Dr. Stoler is board certified by the American Board of Internal Medicine in Interventional Cardiology. He serves as the Co-Medical Director of Cardiology and Medical Director of the Cardiac Catheterization Lab at Baylor Scott & White Heart and Vascular Hospital in Dallas in addition to his involvement in research. Dr. Stoler has published multiple cardiology related articles in peer reviewed medical journals and books, and he continues to be a principal investigator in many national clinical trials. His professional and clinical research interests and expertise lie in the various percutaneous treatments for coronary and structural heart disease and he is regularly invited to proctor cases across the United States for all three commercially available valve platforms:  Evolut, Sapien and Lotus.

Dr. Stoler was appointed Clinical Professor of Medicine at the Texas A&M Health Science Center College of Medicine. Since 2006, Dr. Stoler has appeared annually on D Magazine’s list of “Best Doctors” in Dallas as voted by his peers and as a “Super Doctor” in Texas Monthly magazine. Dr. Stoler was also recently named “Best of the Best” by Patients’ Choice Award for his consistently high ratings by his patients. After receiving his undergraduate and medical degree from Duke University, Dr. Stoler served his internship and residency in Internal Medicine at University of Texas Southwestern Medical Center in Dallas. He completed his fellowship in Cardiology and Interventional Cardiology at Beth Israel Hospital, Harvard Medical School in Boston. Dr. Stoler is recognized as a Fellow of the American College of Cardiology and The Society for Cardiovascular Angiography and Interventions. He is an active member of Dallas County Medical Society and Texas Medical Association.