By Jeffrey Zimmet, MD, PhD

Associate Professor of Medicine, University of California, San Francisco; Director, Cardiac Catheterization Laboratory, San Francisco VA Medical Center

SYNOPSIS: An analysis of a real-world database revealed 14% of patients undergoing routine transfemoral transcatheter aortic valve replacement required permanent pacemaker implantation within 30 days of the valve procedure. There was no difference in long-term survival between patients who did and did not undergo pacemaker implant.

SOURCE: Rück A, Saleh N, Glaser N. Outcomes following permanent pacemaker implantation after transcatheter aortic valve replacement: SWEDEHEART observational study. JACC Cardiovasc Interv 2021;14:2173-2181.

Transcatheter aortic valve replacement (TAVR) has expanded dramatically over the past decade. This procedure was limited to patients who were at prohibitive or high risk of surgical complications, and primarily involved patients of advanced age with significant comorbidities. As TAVR has expanded to younger and lower-risk patients, it has become increasingly important to understand the differences in outcomes between surgical AVR and TAVR. Mechanical pressure from the TAVR valve itself, along with inflammation following valve deployment, results in an increased risk of high-grade atrioventricular block requiring permanent pacemaker implantation following TAVR. The ventricular desynchrony induced by right ventricular pacing has been associated with higher rates of atrial fibrillation, reduced ejection fraction, and clinical heart failure. The effect of this higher pacemaker risk on longer-term outcomes after valve replacement is uncertain. Rück et al examined the records of all patients who underwent transfemoral TAVR in Sweden between 2008 and 2018, using the SWEDEHEART registry. Of 4,750 TAVR patients during this period, the authors excluded those with non-transfemoral access (581 patients), those with preoperative permanent pacemakers (465 patients), and those who underwent valve-in-valve procedures (160 patients). A total of 124 patients who died within 30 days of the procedure also were excluded. This left 3,420 patients for analysis.

From this group, 481 underwent permanent pacemaker implantation within 30 days after TAVR. The mean age of the study population was 81 years, and half were women. Patients who received pacemakers were more likely to be men and recorded a higher prevalence of atrial fibrillation, diabetes, prior MI, and prior cardiac surgery. Balloon-expandable valves were used less frequently in patients who received pacemakers vs. those who did not. During a median follow-up of 2.7 years (interquartile range = 2.5 years; maximum = 11.8 years), there was not a significant difference in survival between those patients who received pacemakers and those who did not. The survival rates at one, five, and 10 years were 90.1%, 52.7%, and 10.9% in the pacemaker group and 92.7%, 53.8%, and 15.3% in the non-pacemaker group, respectively. Similarly, there was no significant difference in cardiovascular death between groups.

The incidence of endocarditis was not different in the pacemaker and no pacemaker groups (2.9% and 2.6%, respectively). Heart failure hospitalization was numerically higher in the pacemaker group (15%) than in the non-pacemaker group (9.3%), but this did not meet statistical significance (HR, 1.23; 95% CI, 0.92-1.63; P = 0.157). The authors did not find a difference in long-term survival between patients who did and did not require permanent pacemaker implantation after TAVR.

COMMENTARY

Much of the editorial commentary regarding this study centers on the term “reassuring.” That is, the lack of a signal for higher long-term mortality rates among patients who required pacemaker implantation post-TAVR gives reassurance these patients are not experiencing harm.

One of the more illuminating comparisons comes from a previous publication from the same research group, which found permanent pacemaker implantation after surgical AVR was associated with a higher risk for heart failure hospitalization and all-cause mortality.1 The major difference here, as Rück et al noted, is surgical AVR patients historically are younger and present with fewer comorbidities vs. TAVR patients. Those undergoing TAVR during the examined period likely died of other causes before the full detrimental effects of permanent pacing become fully evident, at least in terms of hard outcomes, including death and congestive heart failure hospitalization. For these patients, the results of the Rück et al study are reassuring.

There is no mystery when it comes to the negative effects of long-term right ventricular pacing. The question Rück et al hoped to answer concerned the potential deleterious effects of permanent pacing in patients who are younger and with longer life expectancy. For this group, the study adds little. These are the patients in whom TAVR is increasingly applied and for whom the decision between surgical AVR and TAVR will need to consider not only the relative morbidity of the surgery and longevity of the implant, but also the persistent difference in post-implant pacemaker requirement that is likely to remain in surgery’s favor. We are certain to see more discussion of this issue in the future, as more contemporary data become available.

REFERENCE

  1. Glaser N, Persson M, Dalén M, Sartipy U. Long-term outcomes associated with permanent pacemaker implantation after surgical aortic valve replacement. JAMA Netw Open 2021;4:e2116564.