Abstract 18349: The Impact of Concomitant Mitral Regurgitation on Aortic Valve Intervention Outcomes in Paradoxical Low-Flow Low-Gradient Severe Aortic Stenosis

Background: Patients with paradoxical low flow low gradient severe aortic stenosis (LFLGAS) exhibit low transvalvular flow rates due to reduced stroke volumes, while maintaining preserved left ventricular ejection fraction (LVEF). The presence of mitral regurgitation (MR) adds complexity to this already challenging diagnosis, by further lowering flow rate. However, the impact of aortic valve intervention in this patient population remains uncertain.

Methods: A total of 1178 patients were included from an institutional echo database with adjudicated aortic valve area (AVA <1.0 cm2), transaortic gradients (mean gradient< 40 mmHg) and low flow rate (Q ≤210 ml/sec), to confirm the diagnosis of LFLGAS and preserved LVEF (>50%). Subgroups were formed based on the presence of severe MR and subsequent surgical and transcatheter aortic valve intervention (SAVR/TAVR). Patients who underwent mitral valve intervention were censored. All-cause mortality was assessed as the primary outcome.

Results: Patients with severe MR had significantly lower flow rates compared to patients w/o severe MR (166.5 ± 26.3 vs 174.7 ± 25, p=0.006). During a median follow up of 1.3 years, 745 deaths (62.2%) were identified, with a cumulative incidence significantly lower in the intervention groups (Figure). After multivariate propensity adjustment for age, sex, aortic valve area and comorbidities, aortic valve intervention showed a significant reduction in mortality risk in both intervention groups, which was more pronounced in the severe MR group compared to patients w/o severe MR (AdjHR 0.334, p=0.015 vs 0.436, p<0.001, p for interaction =0.24).

Conclusions: In paradoxical low-flow low-gradient severe aortic stenosis, aortic valve intervention results in a survival benefit, especially among patients with concomitant severe MR. Our findings highlight the importance of recognizing severe MR as a flow-diverting lesion that can impact outcomes in LFLGAS.