Demographics and clinical outcomes of flow-gradient patterns of aortic stenosis: an analysis of the CURRENT AS Registry-2

Abstract Background Low-gradient (LG) severe aortic stenosis (AS) has not been fully characterized compared with high-gradient (HG) AS. Methods Among 3369 patients with severe AS enrolled in the CURRENT AS Registry-2, the current study population consisted of 3363 patients with data on left ventricular ejection fraction (LVEF) after excluding patients with LG AS without indexed stroke volume data. Patients were divided into 4 groups (LG AS with reduced LVEF: N=285, paradoxical low-flow low-gradient [LFLG] AS: N=220, normal-flow low-gradient [NFLG] AS: N=872, and HG AS: N=1986). Results Compared to HG AS, LG AS with reduced LVEF more often had cardiovascular comorbidities, advanced cardiac damage stages, and frailty with less extensive aortic valve (AV) calcification by computed tomography (CT), and paradoxical LFLG AS more often had atrial fibrillation, concomitant valvular disease, advanced cardiac damage stages, and frailty with less extensive AV calcification, while NFLG AS were less often symptomatic, and had comparable cardiac damage stages, and frailty with less extensive AV calcification. Patients with the 3 types of LG AS less often underwent surgical or transcatheter aortic valve replacement than those with HG AS (cumulative 3-year incidence: LG AS with reduced LVEF: 64.5%, paradoxical LFLG AS: 59.1%, NFLG AS: 54.2%, and HG AS: 87.3%, P<0.001). Cumulative 3-year incidence of death or heart failure hospitalization was much higher in patients with LG AS with reduced LVEF and paradoxical LFLG AS than in those with HG AS (cumulative 3-year incidence: LG AS with reduced LVEF: 65.9%, paradoxical LFLG: 51.1%, NFLG: 35.5%, and HG: 30.5%, P<0.001). After adjusting confounders, LG AS with reduced LVEF and paradoxical LFLG AS compared with HG AS were independently associated with higher risk for death or heart failure hospitalization (HR: 1.82, 95%CI: 1.49-2.23, P<0.001; HR 1.43, 95%CI: 1.13-1.82, P=0.003, respectively), but not NFLG AS (HR 1.03, 95%CI: 0.88-1.21, P=0.68). Conclusions Aortic stenosis might be less severe in LG AS than in HG AS when assessed by the CT calcium score of the aortic valve, and each of the 3 hemodynamic types of LG AS had distinct clinical, and echocardiographic characteristics as well as clinical outcomes that were different from HG AS.Different patterns of severe AS