Background

Recent studies have shown that factors such as valve-calcification patterns, bundle branch blocks, membranous septum length and implantation depth contribute to an increased risk of permanent pacemaker (PPM) after percutaneous aortic valve replacement (TAVI). However, it is unclear, to what extent each risk factor contributes to a potential need for PPM. This study assessed the independent risk factors and integrated them into a comprehensive risk score to facilitate future clinical PPM risk-assessment.

Methods

A total of 797 patients with severe aortic stenosis undergoing TAVI between January 2019 and December 2020 were included in the TAVI-PACER-study, a retrospective, multicenter and multimodal study. A dedicated CoreLab consisting of experienced cardiologists and radiologists assessed contrast-enhanced computed tomographic parameters using the 3mensio software (version 10.2, Maastricht, The Netherlands), echo- and electrocardiographic parameters as well as procedural parameters and patient characteristics to identify risk factors for PPM and creating a predictive, comprehensive risk score.

Results

Among the 797 patients undergoing TAVI, 15,6% developed higher-degree rhythm disturbances (71% third-degree AV block, 16.1% bradyarrhythmia, 10.5% second-degree AV block type Mobitz, 2.4% sinoatrial block) requiring a PPM-implantation within the index hospitalization after TAVI. Parameters strongest associated with an increased PPM risk were electrocardiographic parameters such as right bundle branch block (RBBB) (OR 3.91, 95% CI 2.37-6.50, p<0.001), prolonged PQ intervals (OR 0.46, 95% CI 0.28-0.76, p<0.05) and prolonged QRS duration (OR 0.61, 95% CI 0.40-0.93, p<0.05). With respect to morphologic predictors assessed by CT and echocardiography, length of the membranous septum (OR 0.93, 95% CI 0.83-1.03, p<0.05) was the only significant factor being associated with PPM, whereas interventricular septum thickness (IVSDd; OR 1.04, 95% CI 0.99-1.10, p=0.15) as well as presence of calcifications in the LVOT (OR 1.16, 95% CI 0.70-1.91, p=0.575) and non-coronary cusp (NCC; OR 1.00, 95% CI 1.00-1.00, p=0.49) showed no association with PPM rates, similar to  LCC- and RCC-calcifications (OR 1.00, 95% CI 1.00-1.00, p=0.80 and OR 1.00 95% CI 1.00-1.00, p=0.86).

Conclusion

The present study confirms in a recent, large, multicenter patient cohort that particularly electrophysiological factors such as pre-existing atrioventricular and ventricular conduction disturbances and increased IVSD are associated with PPM after TAVI. Importantly, CT-assessed calcifications failed to predict PPM risk and therefore seem to be less relevant factors for patients’ individual PPM risk following TAVI.