Predictors of PPM Implantation

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Predictors of PPM Implantation

Pre-existing Conduction Abnormalities and Anatomical Conditions

Patients undergoing TAVR have similar rates of pre-existing conduction disease as SAVR patients, which are described at 40–50 % in both surgical and transcatheter populations^4,6. In an early study with the self-expanding Medtronic CoreValve Prosthesis (MCP, Medtronic, Minneapolis, Minnesota), left bundle-branch block (LBBB) at baseline, increased interventricular septal diameter (>17 mm) and increased non-coronary aortic cusp thickness (>8 mm) were highly predictive for PPM (receiver operating characteristic area 0.93±0.055, P< 0.001)⁷. In this analysis, non-coronary aortic cusp thickness was the strongest predictor (P=0.002, correlation coefficient =0.655). A similar study by Baan et al.⁸ found in 34 MCP patients that small left-ventricular outflow tract diameter, left axis deviation, significant mitral annular calcification and lower post-implant valve area are predicting post-TAVR PPM. Several studies showed that right bundle-branch block (RBBB) at baseline is one of the most significant predictors of PPM after TAVR^9–14. Additionally, baseline first-degree atrioventricular (AV) block¹⁰, left anterior hemiblock¹² and intraprocedural AV block¹⁵ are important predictors for PPM dependence. Most of the previously mentioned studies looked at a low number of cases. In contrast to the recent meta-analysis of Siontis et al., RBBB (n=2158; risk ratio (RR): 2.89 (CI: 2.36–2.54), p<0.01), baseline AV block (n=1381; RR: 1.52 (CI: 1.15–2.01), p<0.01), and left anterior hemiblock (n=1065; RR: 1.62 (CI: 1.17–2.25), p<0.01) were the strongest predisposing conduction disturbances for PPM¹⁶. Figure 1 emphasises the close anatomical relationship of the cardiac conduction system referring to the aortic valve and highlights the importance of pre-existing conduction abnormalities as a predictor for PPM after TAVR.