Impact of valvuloarterial impedance on 2-year outcome of patients undergoing transcatheter aortic valve implantation

Background: Elderly patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI) often have increased calcification and fibrosis of the aorta. Indices that account for the severity of valvular obstruction and systemic vascular impedance may better assess total left ventricular afterload. The aims of the present study were to evaluate changes in valvuloarterial impedance (Z_va), systemic arterial compliance, and systemic vascular resistance after TAVI and to investigate the prognostic value of these parameters. Methods: A total of 116 patients (49% men; mean age, 81 ± 8 years) with symptomatic severe aortic stenosis underwent TAVI. Z_va, systemic arterial compliance, and systemic vascular resistance were measured at baseline and 1 and 12 months after TAVI. The primary end point was all-cause mortality. Results: After TAVI, there was a significant reduction in Z_va (from 5.40 ± 1.52 mm Hg/mL/m ² at baseline to 4.13 ± 1.17 mm Hg/mL/m² at 1 month and 4.35 ± 1.38 mm Hg/mL/m² at 1 year, P <.001). Systemic arterial compliance (from 0.57 ± 0.27 to 0.57 ± 0.28 and 0.53 ± 0.27 mL/m²/mm Hg, P =.408) and systemic vascular resistance (from 1,938 ± 669 to 1,856 ± 888 and 1,871 ± 767, dyne·s·cm^-5, P =.697) did not change significantly over time. During a median follow-up period of 25 months, survival rates of patients with baseline Z_va ≥ 5 mm Hg/mL/m² were lower compared with those with Z_va < 5 mm Hg/mL/m² (82% vs 91%, respectively, log-rank P =.04). On multivariate Cox proportional-hazards analysis, baseline Z_va was independently associated with all-cause mortality (hazard ratio, 1.48; 95% confidence interval, 1.05-2.07; P =.025). Conclusions: In patients undergoing TAVI, there is a significant postprocedural reduction in Z_va, but there is no reduction in systemic arterial compliance or vascular resistance. Baseline Z_va is an independent predictor of overall mortality at 2-year follow-up.