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Needing a permanent pacemaker after surgical aortic valve replacement (SAVR) was linked to mortality in Swedish registry data.

Such risk was not apparent in the first few years: all-cause mortality reached 38.3% over follow-up averaging 7.3 years among SAVR recipients who required a new pacemaker and a comparable 41.3% of peers who did not experience this complication of surgery.

But when the authors turned to look at survival rather than at mortality, Kaplan-Meier estimated survival rates showed a noticeable difference between pacemaker and non-pacemaker groups at 10 years (52.8% vs 57.5%) and 20 years 18.0% vs 19.6%).

Pacemaker recipients had significantly higher rates of all-cause mortality (HR 1.14, 95% CI 1.01-1.29) and heart failure hospitalization (HR 1.58, 95% CI 1.31-1.89) over the entire up to 22 years of follow-up.

No statistically significant increase was found in the risk of endocarditis in the pacemaker group, researchers led by Natalie Glaser, MD, PhD, of Stockholm South General Hospital reported .

These findings add to the notion that the risk of permanent pacemaker implantation should be an important consideration in the modern age of aortic valve replacement (AVR), especially as transcatheter operations expand to younger patients at lower surgical risk.

In practice, pacemaker rates range from 9% to 26% after transcatheter aortic valve replacement (TAVR), compared with 3% to 5% after SAVR, Glaser's group noted.

"Although our results cannot be directly generalized to patients who underwent TAVR, it is likely that our findings may be valid in TAVR patient populations," the authors said.

The clinical significance of pacemaker implantation after AVR has been a subject of debate given the conflicting results of prior long-term studies, the authors said. "Furthermore, these studies are limited by their small patient numbers, short follow-up times, and single-center designs."

"Our findings suggest that the association of permanent pacemaker implantation with adverse outcomes becomes clinically apparent over a longer follow-up period," the group concluded. "These findings further suggest that future research should investigate how to avoid permanent pacemaker dependency after surgical and transcatheter AVR."

Glaser and colleagues relied on the SWEDEHEART registry for their cohort study. The database identified all SAVR patients from 1997 to 2018 in Sweden, where there are eight centers offering cardiac surgery.

People undergoing concomitant coronary artery bypass grafting or surgical treatment of the ascending aorta were included in the study. Excluded were patients who underwent preoperative permanent pacemaker implantation, concomitant surgical treatment for another valve, or emergency SAVR.

In the end, the study included 24,983 SAVR recipients who had a mean age of around 70 and 36.9% of whom were women.

Conduction system damage during surgery resulted in 3.4% of patients requiring permanent pacemaker or implantable cardioverter defibrillator implantation in the first 30 days after SAVR.

This group was more likely to have preoperative heart failure and less likely to receive concomitant CABG compared with patients not requiring pacemakers but was otherwise comparable at baseline.

Study results pointed to a non-significant association between permanent pacemaker implantation and cardiovascular death.

"This may have been associated with the low number of events, and we believe that a larger study may indeed find an increased risk of cardiovascular death among patients who undergo permanent pacemaker implantation after AVR," Glaser's team said.

The potential for residual confounding was another major limitation of the retrospective study.

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