Left Ventricular Outflow Tract Morphology as a Predictor of Conductance Disturbances Following Transcatheter Aortic Valve Replacement.

Background: Conduction disturbances represent one of the most common complications following transcatheter aortic valve replacement (TAVR). We sought to investigate the role of left ventricular outflow tract (LVOT) morphology in the development of conduction disturbances following TAVR.

Methods and results: Consecutive patients who underwent TAVR in our center were included. The ratio between the LVOT area and the aortic annulus area was calculated. Patients were then divided into 2 groups on the basis of this ratio: group 1, which included patients with an LVOT area/aortic annulus area ratio <0.9; and group 2, which included patients with an LVOT area/aortic annulus area ratio ≥0.9. The primary end point was to assess the relationship between LVOT shape and the rate of permanent pacemaker implantation following TAVR. A multivariable analysis was performed to identify predictors of permanent pacemaker implantation following TAVR. From January 2018 to December 2020, 276 patients were included. Ninety-one patients with tapered LVOT morphology were assigned to group 1 and the rest (n=185 patients), tubular LVOT or flared LVOT shape, to group 2. The mean age was 81.5±5.7 years and 57% were women. After adjusting by confounding factors, tapered morphology of the LVOT and prior right bundle-branch block were found to be independent predictors of permanent pacemaker implantation (hazard ratio [HR], 2.6 [95% CI, 1.2-5.7]; P=0.014; and HR: 4.3 [95% CI 2.4-7.6], P<0.001); at a median follow-up time of 15.5 (interquartile range, 15) months.

Conclusions: A tapered-LVOT morphology was associated with increased risk for permanent pacemaker implantation. LVOT morphology may be an additional factor to consider when choosing prosthesis size.