Background: Transcatheter aortic valve implantation (TAVI) is commonly associated with the development of conduction disorders due to the close proximity of the conduction system to the aortic valve. Fractional shortening (FS) is a measure of left ventricular (LV) contractility calculated from the difference in LV basal diameters close to the conduction system. We hypothesized that FS may be related to the risk for permanent pacemaker (PPM) requirement or development of a new left bundle branch block (LBBB) when prosthetic valves that protrude into the LV outflow tract are implanted,
Methods: A total of 308 patients (mean age of 81.5±6.5 years) with severe symptomatic aortic stenosis (AS) and without prior PPM underwent TAVI in our institute using CoreValve (70%) or Edwards-SAPIEN (30%) prosthetic devices. We investigated independent predictors for PPM implantation. The relation between FS and PPM requirement or new LBBB was evaluated both as a continuous and a categorical variable.
Results: Fifty one patients (17%) underwent PPM implantation and 136 patients (44%) had PPM implanted or developed new LBBB during hospitalization. Multivariate analysis demonstrated that baseline RBBB, CoreValve prosthetic device, valve size and FS were independent predictors of PPM implantation. Patients with high FS (>40%, upper quartile) had a 3-fold (p=0.003) increased risk for PPM implantation and 2.2-fold (p=0.011) increased risk for PPM or new LBBB. Consistently, every 10% increment in FS was associated with 80% (p=0.003) and 48% (p=0.011) increase in the risk for PPM implantation, and PPM implantation or new LBBB, respectively. In a separate model, shorter LV end systolic diameter (LVESD) also predicted PPM implantation (odds ratio (OR) per every cm decrease =2.08, p=0.012).
Conclusions: In this study we have found that baseline FS is an independent predictor for PPM implantation, suggesting that this simple measure may be used to guide clinical decision making before TAVI.
