Patients undergoing permanent pacemaker implantation after surgical aortic valve replacement (SAVR) are at increased risk of all-cause mortality and heart failure hospitalisation, according to the findings of a Swedish observational study published in JAMA Network Open.
Authors of the study, Natalie Glaser (Department of Cardiology, Stockholm South General Hospital, and Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden) and colleagues, examined 24,983 patients who underwent SAVR in Sweden from 1997‒2018 in order to investigate long-term outcomes after primary surgical aortic valve replacement among patients who underwent postoperative permanent pacemaker implantation, with a primary outcome of all-cause mortality.
Aortic valve replacement (AVR), they write, is associated with radically improved prognosis among patients with severe aortic valve disease, but surgical and transcatheter AVR carry risks of perioperative damage to the conduction system, sometimes requiring permanent pacemaker implantation. Prior studies investigating the long-term clinical outcomes of patients who have undergone permanent pacemaker implantation after aortic valve replacement reported conflicting results, they note.
Data were extracted from the Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART) registry and included all patients who underwent primary SAVR in the eight Swedish centres that perform cardiac procedures. Among the 24,983 patients who were eligible for study, 849 (3.4%) underwent permanent pacemaker implantation within 30 days after surgical treatment and 24,134 (96.6%) did not receive pacemakers in that time.
The mean age of the total study population was 69.7 (10.8) years, and 9,209 patients were women (36.9%). The mean (SD) and maximum follow-up periods were 7.3 years and 22 years, respectively.
At 10 years and 20 years after surgical treatment, the Kaplan-Meier estimated survival rates were 52.8% and 18% in the pacemaker group, respectively, and 57.5% and 19.6% in the non-pacemaker group, respectively.
According to Glaser and colleagues, all-cause mortality was statistically significantly increased in the pacemaker group compared with the non-pacemaker group (hazard ratio [HR], 1.14; 95% CI, 1.01‒1.29; p=0.03), as was risk of heart failure hospitalisation (HR, 1.58; 95% CI, 1.31‒1.89; p<0.001). Meanwhile, no statistically significant increase was found in the risk of endocarditis in the pacemaker group.
Discussing the findings of the study, Glaser et al point to data collected by Kevin Greason (Mayo Clinic, Rochester, USA) and colleagues, analysis 5,842 patients who underwent SAVR from 1993–2014. Permanent pacemakers were implanted in 2.5% of patients within 30 days after surgical treatment, and the mortality rate at 10 years was 65% in the pacemaker group. Permanent pacemakers were implanted in 2.5% of patients within 30 days after surgical treatment, with worse long-term survival noted among patients who underwent permanent pacemaker implantation.
Glaser et al write that their findings support the conclusions drawn by Greason et al and provide “robust data obtained from a nationwide and contemporary patient cohort consisting of almost 25,000 patients.”
Additionally, the study’s authors suggest that the findings may be clinically relevant in patients who have undergone transcatheter aortic valve implantation (TAVI). They write: “The prevalence of permanent pacemaker implantation after transcatheter AVR is consistently increased compared with the prevalence after surgical AVR. Although our results cannot be directly generalised to patients who underwent transcatheter AVR, it is likely that our findings may be valid in transcatheter AVR patient populations. The results of our study are clinically relevant, especially in an era when transcatheter AVR is used among younger patients with lower surgical risk.”
Limitations of the study include that the authors were unable to discriminate between patients with a high pacing burden and low or no pacing dependency during follow-up, and that it did not investigate other central aspects of well-being, such as quality of life or functional capacity.
And, Glaser et al note that while they adjusted for a range of comorbidities and socioeconomic factors, there were factors that were unknown or unmeasured for which they were unable to adjust, including preoperative electrocardiographic characteristics and indications for pacemaker implantation. “Thus, this study allows for demonstrating associations rather than causality,” they add.
In conclusion, Glaser and colleagues write: “We observed an increased risk of all-cause mortality and heart failure hospitalisation among patients who underwent permanent pacemaker implantation after SAVR. We found no association between permanent pacemaker implantation and risk of endocarditis. Our findings are important to consider, especially in an era when transcatheter AVR is used among younger patients at lower risk of adverse surgical outcomes. These findings suggest that future research should investigate how to avoid permanent pacemaker dependency after surgical and transcatheter AVR.”