Low gradient aortic stenosis and TAVI: The differential prognostic value of valvular and aortic calcifications may traduce a particular pathophysiology

Abstract

Low gradient aortic stenosis (LGAS) is still poorly understood. The valular aspect may be less prominent than in the other forms of aortic stenosis (AS) and intertwined with other aspects such as vascular ones. The severity of the valvular disease was assessed from aortic valvular calcifications (VAC) and that of aorta from thoracic aortic calcifications (TAC). To assess the prognostic significance of VAC and TAC in patients with and without LGAS treated by TAVI. Ancillary study of the C4CAPRI trial including 1282 consecutive patients from 4 French hospitals. The primary outcome was 3 years CV mortality after TAVI. 397 (31%) had a LGAS. They were more frequently men, younger, with atrial fibrillation (AF), and lower left ventricular ejection fraction (LVEF), P < 0.05 for all. VAC was lower in LGAS (1.05 cm 3 ± 0.7 vs. 0.75 cm 3 ± 0.5), P < 0.001, while the opposite was noticed for TAC, (3.1 cm 3 ± 3 vs. 3.7 cm 3 ± 3.7), P = 0.01. After 3 years, 227 (17.7%) patients died from CV causes; respectively 85(21.4%) and 142(16.1%) patients with and without LGAS, P = 0.02. Multivariate analysis was adjusted for TAC, VAC, age, gender, AF, LVEF, pulmonary systolic pressures, history of diabetes, chronic respiratory disease, renal insufficiency and peripheral vascular disease. In LGAS patients TAC HR 1.090 CI (1.02–1.16) but not VAC was a predictor of CV mortality while in patients without LGAS, VAC HR 1.377 CI (1.049–1.809) but not TAC was associated with CV mortality. The present study confirms that valvular disease seems less prevailing in LGAS patients than in other forms of AS. On the other hand, vascular after load, estimated by TAC, conveys a major prognostic information in this subgroups. This has clinical impact: VAC may be a marker of early and periprocedural mortality and aortic regurgitation in non-LGAS patients, while TAC may continue to increase left ventricular after load in patients with LGAS whom LVEF is often impaired.