Impact of Nodular Calcifications in the Aortic Annulus and Left Ventricular Outflow Tract on TAVI Outcome with New-Generation Devices.

Abstract

The impact of nodular calcifications in left ventricular outlow tract (LVOT) and aortic annulus on the procedural outcome of transcatheter aortic valve implantation (TAVI) with new-generation devices is yet to be elucidated. Similarly, computational simulations may provide a novel insight into the biomechanical features of TAVI devices and their interaction with nodular calcifications. This retrospective single-center study included 232 patients submitted to TAVI with Evolut-R (53.4%), Portico (33.6%) and Lotus (13.0%) devices with available preoperative computed tomography (CT) angiography and evidence of nodular calcifications in aortic annulus and/or LVOT. Calcification severity was defined moderate in presence of at least two nodules or one nodule 5 mm. Three virtual simulation models of aortic root presenting a nodular calcification of increasing size were implemented. Stress distribution, stent-root contact area and paravalvular orifice area were computed. At least moderate calcifications were found in 123 (53.0%) patients, with no sex differences. Among the moderate calcification group, lower device success rate was evident (87.8% vs. 95.4%; p = 0.039). Higher rates of moderate paravalvular leak (PVL) (11.4% vs. 3.7%; p = 0.028) and vascular complications (9.8% vs. 2.8%; p = 0.030) were also observed. Among the Evolut-R group, higher rates of at moderate PVL (12.1%) were observed compared to Portico (3.8%; p = 0.045) and Lotus (0.0%; p = 0.044) groups. Calcification of both annulus and LVOT (odds ratio [OR] 0.105; p = 0.023) were independent predictors of device success. On computational simulations, Portico exhibited homogeneous stress distribution by increasing calfications and overall a larger paravalvular orifice areas compared to Evolut-R and Lotus. Evolut-R showed higher values of average stress than Portico, although with a more dishomogeneous distribution leading to greater paravalvular orifice areas by severe calcifications. Lotus showed overall small paravalvular orifice areas, with no significant increase across the three models. At least moderate nodular calcifications in the annulus/LVOT region significantly affected TAVI outcome, as they were independent predictors of device success. Lotus and Portico seemed to perform better than Evolut-R as for device success and moderate PVL. Computational simulations revealed unique biomechanical features of the investigated devices in terms of stent compliance and radial force.