New-Onset Conductance Disturbances After Transcatheter Tricuspid Valve Replacement: A Mechanistic Assessment.

Background The anatomical relationship between the tricuspid annulus and the conduction system increases the risk for new-onset conductance disturbance (NOCD) following transcatheter tricuspid valve replacement (TTVR).Objectives The aim of this study was to describe the incidence and types of NOCD and potential risk factors. Methods This was a single-center, retrospective analysis of TTVR patients. The primary endpoint was 30-day NOCD incidence. Subgroups with (NOCD+) and without (NOCD-) conduction disturbances were compared. Echocardiographic measures of tricuspid valve and right ventricular size, morphology, and function as well as post-TTVR computed tomographic device position within the annulus were assessed. Results Seventy patients were included in this analysis, of whom 31 (44.3%) developed NOCD, which included right bundle branch block, complete atrioventricular block and slow atrial fibrillation. New permanent pacemaker implantation was required in 8 patients (14%) within 30 days. Baseline absolute right ventricle free wall longitudinal strain was significantly higher in NOCD+ patients (29.7% ± 5.4% vs 25.1% ± 6.4%; P = 0.002). Type IIIB leaflet morphology was more prevalent in NOCD+ patients (48.4% vs 25.6%; P = 0.049). No difference was found regarding membranous septum (MS) dimensions or device oversizing. The postprocedural incidence of white blood cell count peak > 13 × 109/L was higher in NOCD+ patients (51.6% vs 28.2%; P = 0.046). By logistic regression, the primary outcome was associated with baseline absolute right ventricle free wall longitudinal strain ≥29% and contact of subvalvular device component with the MS on follow-up computed tomography. Conclusions NOCD incidence was 44.6% after TTVR in a highly selected patient population. Baseline hyperdynamic right ventricular function and contact of the device with the MS were independently associated with NOCD at 30 days. Further studies are warranted.