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

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).

The aim of this study was to describe the incidence and types of NOCD and potential risk factors.

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.

A total of 70 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.

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.