A comparison of long-term survival between patients who either did or did not undergo permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement (TAVR) revealed no differences, according to 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 frequent complications
While newer-generation aortic valve prostheses are less likely to necessitate PPI, the need for PPI is higher after TAVR than after surgical aortic valve replacement (SAVR), and the need for PPI remains the most frequent complication after TAVR, the study authors noted. Use of self-expandable valves, deep prosthetic valve implantation, preprocedural conduction disturbances, older age, and a high number of comorbidities are among the risk factors for PPI following TAVR.
With prior studies producing conflicting results, the authors stated, the impact of PPI after TAVR remains unknown. Expanding use of TAVR to include younger and low-risk patients with a long life expectancy underscores the importance of gaining greater understand of the impact of PPI after TAVR. Accordingly, the study was conducted to investigate long-term, clinically important outcomes in this post-TAVR population.
Out of 4,750 patients who underwent TAVR in the study period, 3,420 patients in SWEDEHEART met study criteria, with 481 (14.1%) undergoing PPI within 30 days after TAVR, and 2,939 not receiving a pacemaker. PPI exposure was defined as implantation of a permanent pacemaker or implantable cardioverter-defibrillator. The study primary outcome was all-cause mortality, with cardiovascular death, heart failure, and endocarditis as secondary outcomes. It was reported in
Mean patient age was 81.3 years (50.4% female). The rate for all-cause mortality in those with no pacemaker was 11.4 per 100 patient years and 13.1 for those with a pacemaker (hazard ratio, 1.04; 95% confidence interval, 0.89-1.23). The cardiovascular death rate in the no-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 no pacemaker group and 6.3 in the pacemaker group (HR, 1.22; 95% CI, 0.93-1.672). Endocarditis rates were 1.2 and 1.1 per 100 patient years in the no pacemaker and pacemaker groups, respectively (HR, 0.93; 95% CI, 0.51-1.71).
The authors pointed out that their prior study had found PPI after SAVR in almost 25,000 patients to be associated with increased all-cause mortality and heart failure rates. Patients who undergo TAVR, however, are older and have more comorbidities than patients who undergo SAVR.
It is thus likely that patients who undergo TAVR die of other causes before the negative effects of their pacemaker become clinically evident.
Also, the incidence of conduction abnormalities increases with age, making it more likely that beneficial effects of pacemakers occur in older patients rather than younger ones, counterbalancing the detrimental effects to a larger extent.
Reduce PPI rates after TAVR
The study authors also observed that, although they did not find increased mortality or heart failure in patients who underwent PPI, PPI is associated with risks, including lead- and pocket-related complications, other traumatic complications, longer hospital stays and higher societal costs. These factors justify the search for strategies to reduce PPI rates after TAVR.
“Our study adds important information about the prognosis in patients who received a permanent pacemaker implantation following TAVR,” study author
In an accompanying, , and Erika Muñoz-García, MD also noted factors potentially counterbalancing and masking adverse effects of PPI, echoing some mentioned by the study authors. Among those without PPI, 10%-50% develop new-onset left bundle branch block (LBBB) after TAVR. LBBB is a known marker of low long-term survival in TAVR populations, producing intraventricular dyssynchrony leading potentially to left ventricular dysfunction or development of complete atrioventricular block with higher mortality risk in those without pacemakers. PPI, as well, can be protective against unexpected death in those with advanced conduction disorders. Still, they point out, PPI can entail lead dysfunction, need for generator replacement, infection, and tricuspid valve regurgitation.
Commenting in an interview that an observed trend of a greater increase in events in the group of patients with pacemakers for the first 4 years is consistent with, Dr. Antonio Muñoz-García said: “This can be explained because long-term survival in the TAVI population is conditioned by comorbidities. It is true that the presence of a pacemaker can cause left ventricular ejection fraction to deteriorate and therefore condition 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 pacing, whether or not the patients prior to TAVI present with alterations in atrioventricular conduction [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 issues to be considered in clinical practice.”
The editorialists concluded: “To date, the impact of PPI on late clinical outcomes after TAVR remains controversial; however, this study to some extent helps clarify this controversy.” In accord with the study authors, they called for reductions in PPI rates and long-term clinical follow-up.
The study was funded by several Swedish research organizations. The study investigators and editorial authors declared having no disclosures.