A comparison of long-term survival between patients who either underwent or did not undergo permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement (TAVR) showed no differences according to the results of the SWEDEHEART observational study.

The nationwide population-based cohort study included all patients who underwent transfemoral TAVR in Sweden from 2008 to 2018.

Most common complications

While newer generation aortic valve prostheses are less likely to require PPI, the need for PPI after TAVR is higher than after surgical aortic valve replacement (SAVR), and the need for PPI remains the most common complication after TAVR, the study authors found. The risk factors for a PPI according to TAVR include the use of self-expanding valves, deep prosthetic valve implantation, pre-procedural conduction disorders, old age and a high number of comorbidities.

Because previous studies provided conflicting results, the effects of PPIs after TAVR remained unknown. Expanding the use of TAVR to younger and lower risk patients with a long life expectancy underscores the importance of better understanding the effects of PPIs after TAVR. Accordingly, the study was conducted to investigate long-term, clinically important outcomes in this post-TAVR population.

Of 4,750 patients who underwent TAVR during the study period, 3,420 patients in SWEDEHEART met the study criteria, with 481 (14.1%) receiving a PPI within 30 days of TAVR and 2,939 not receiving a pacemaker. PPI exposure was defined as implantation of a permanent pacemaker or implantable cardioverter defibrillator. The primary endpoint of the study was all-cause mortality with cardiovascular death, heart failure, and endocarditis as secondary endpoints. It was reported in JACC: Cardiovascular Interventions.

Similar survival

The mean patient age was 81.3 years (50.4% female). The overall mortality in patients without a pacemaker was 11.4 per 100 patient-years and 13.1 in patients with a pacemaker (hazard ratio 1.04; 95% confidence interval 0.89-1.23). The cardiovascular death rate in the pacemaker group was 6.0 per 100 patient-years and 7.1 per 100 patient-years in the pacemaker group (HR 0.96; 95% CI 0.75-1.23). For heart failure, the rates were 4.5 per 100 patient-years in the pacemaker group and 6.3 in the pacemaker group (HR 1.22; 95% CI 0.93-1.672). The endocarditis rates were 1.2 and 1.1 per 100 patient-years in the group without pacemaker or pacemaker (HR 0.93; 95% CI 0.51-1.71).

The authors pointed out that in their previous study, PPIs after SAVR were associated with increased all-cause mortality and heart failure rates in almost 25,000 patients. However, patients undergoing TAVR are older and have more comorbidities than patients undergoing SAVR.

It is therefore likely that patients undergoing TAVR will die from other causes before the negative effects of their pacemaker become clinically apparent.

In addition, the incidence of conduction disorders increases with age, making it more likely that the beneficial effects of pacemakers will be more likely to occur in older than younger patients, which more offsets the harmful effects.

Reduce PPI rates after TAVR

The study authors also noted that while PPIs did not identify increased mortality or heart failure in patients undergoing PPIs, they do carry risks, including complications related to electrodes and pouches, other traumatic complications, longer hospital stays, and higher societal costs . These factors justify the search for strategies to lower PPI rates after TAVR.

“Our study provides important information about the prognosis of patients who have had a permanent pacemaker implanted after TAVR,” said study author Natalie Glaser, MD, PhD, in an interview. “The expanded knowledge of the prognosis after TAVR in different patient populations has important implications for preoperative risk stratification and can help optimize postoperative follow-up and treatment for these patients.” Future studies, Glaser added, should include younger, lower-risk patients with longer follow-up to confirm the present results.

Compensation factors

In an accompanying editorial, Antonio J. Muñoz-García, MD, PhD, and Erika Muñoz-García, MD also noted factors that may offset and mask the side effects of PPIs, reiterating some of the study authors’ mention. Among those without PPI, 10–50% develop emerging left bundle branch block (LBBB) after TAVR. LBBB is a well-known marker of low long-term survival in TAVR populations, causing intraventricular dyssynchrony, potentially leading to left ventricular dysfunction or the development of complete atrioventricular block with a higher risk of mortality in patients without a pacemaker. PPI can also protect against unexpected death in patients with advanced conduction disorders. However, they do suggest that PPI can lead to lead dysfunction, generator replacement, infection, and tricuspid regurgitation.

Antonio Muñoz-García commented in an interview that an observed trend of a greater increase in events in the group of pacemaker patients in the first 4 years is in line with previous studies: the TAVI population is caused by comorbidities. It is true that the presence of a pacemaker can cause the left ventricular ejection fraction to deteriorate, leading to heart failure and increased mortality. But the involvement of the pacemaker in left ventricular function in patients with TAVI is multifactorial and depends on the indication of the pacemaker, whether prophylactic or absolute, on the time-dependent stimulation, whether the patients present with changes in the atrioventricular conduction before the TAVI [and therefore could benefit from the implantation of pacemakers], as well as the forms of pacing optimization [resynchronization, hisian pacing, etc]. All of these are questions that need to be considered in clinical practice. “

The editorials concluded: “To date, the impact of PPIs on late TAVR clinical outcomes remains controversial; however, this study helps to some extent to resolve this controversy.” In agreement with the study authors, they called for a reduction in PPI rates and long-term clinical follow-up.

The study was funded by several Swedish research organizations. The investigators and editors of the study stated that they had not provided any information.

This story originally appeared on MDedge.com, part of the Medscape Professional Network.

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