Patients with permanent pacemakers implanted after transcatheter aortic valve replacement (TAVR) did not have any long-term survival benefit over those with no pacemaker, a new analysis of the Swedish SWEDEHEART registry found.
The findings in 3,420 TAVR patients were published online Monday, ahead of the Oct 11 issue of JACC: Cardiovascular Interventions, by Andreas Rück, MD, PhD, from Karolinska Institutet and Karolinska University Hospital, Stockholm, together with colleagues.
Use of TAVR as a treatment for severe aortic stenosis continues to rise; however, the impact of permanent pacemaker implantation after TAVR is unknown, the researchers said, adding that prior studies have produced conflicting results.
This is the despite the fact that TAVR patients are at “high risk” of requiring permanent pacemaker because the aortic valve annulus is adjacent to the conduction system, they said. “Mechanical pressure from the valve prosthesis, local swelling, and periprocedural systemic ischemia may induce high degree atrioventricular block and new onset left bundle branch block.”
Although advances in newer-generation aortic valve prostheses mean lower risk of need for pacemakers, prevalence of pacemaker implants after TAVR ranges from around 9% to 26%, with the highest risk factors associated with self-expandable valves and deep prosthetic valve implantation, the researchers added.
The current study was, therefore, set up to investigate long-term, clinically important outcomes in patients who underwent pacemaker implantation after TAVR – knowledge the researchers stressed is particularly important given that TAVR use is expanding to younger and lower-risk patients with longer life expectancies.
The study included 3,420 patients who underwent transfemoral TAVR in eight Swedish centers from 2008 to 2018 in the SWEDEHEART (Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies) register, 481 (14.1%) of whom underwent permanent pacemaker implantation within 30 days after TAVR.
The patients had a mean age of 81.3 ± 7.2 years, were fairly evenly divided between men and women (50.4% women), but men were the majority in the pacemaker group (56.1%), and the majority had a body-mass index above 25 kg/m2 (55.8%).
Patients who underwent permanent pacemaker implantation had a higher prevalence of atrial fibrillation (43.7% in pacemaker group vs. 39.6% in non-pacemaker patients), diabetes mellitus (32.8% vs. 28.2%, respectively), prior myocardial infarction (29.1% vs. 22.4%, respectively) and prior cardiac surgery (21.4% vs. 15.9% ,respectively). The pacemaker patients had a lower prevalence of balloon-expandable valves (20.2% vs. 41.3%), however, and lower incidence of left ventricular ejection fraction above 50% (60.1% vs. 67.2%).
Following the subjects for all-cause mortality until March 20, 2020, the researchers found the survival rate at 1 year was 90% in the pacemaker group and 92.7% for non-pacemaker subjects, at 5 years was 52.7% for pacemaker vs. 53.8% for non-pacemaker patients, and at 10 years was 10.9% for pacemaker vs. 15.3% for the non-pacemaker group (hazard ratio [HR]: 1.03; 95% confidence interval [CI]: 0.88-1.22; P = 0.692). The results were similar in a propensity-score-matched cohort, and when stratified by sex and left ventricular ejection fraction.
The median follow-up was 2.7 years (interquartile range: 2.5-11.8 years), and total follow-up time was 10,591 patient years.
Cardiovascular death (HR: 0.91; 95% CI: 0.71-1.18; P = 0.611), heart failure (HR: 1.23; 95% CI: 0.92-1.63; P = 0.157) and endocarditis (HR: 0.90; 95% CI: 0.47-1.69; P = 0.734) were followed until Dec 31. 2018, again with no difference in risk between the groups.
“Our study contributes to understanding the impact of pacemaker implantation after transcatheter aortic valve replacement, which is becoming increasingly important as the use of this method expands to include younger and low-risk patients with a long life expectancy,” said the study’s corresponding author, Natalie Glaser, MD, PHD, from Karolinska Institutet and the Stockholm South General Hospital, in a press statement.
The researchers went on to call out “particular strengths” of the study, including the large cohort, long follow-up period, nationwide population-based design and “high accuracy of the Swedish health data registers”.
In an accompanying editorial, Antonio J. Muñoz-García, MD, PhD, and Erika Muñoz-García, MD, from Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), Spain, said: “To date, the impact of PPI on late clinical outcomes after TAVR remains controversial; however, this study to some extent helps clarify this controversy.”
Nevertheless, they stressed that to fully solve the lack of consensus across studies over pacemaker outcomes after TAVR, it is necessary to “reduce the rate of [permanent pacemaker implantation], homogenize criteria and studies, and have long-term clinical follow-up.”
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.
Muñoz-García AJ, Muñoz-García E. Pacemaker Implantation After Transcatheter Aortic Valve Replacement: Controversial Complications With Prognostic Uncertainties— Clearing the Unknowns. JACC Cardiovasc Interv 2021;14:2182-2184.
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