Concomitant mitral regurgitation in patients with low-gradient aortic stenosis: an analysis from the German Aortic...

Patients with severe aortic stenosis (AS) frequently presented mitral regurgitation (MR), which may interfere with the standard echocardiographic measurements of mean pressure gradient (MPG), flow velocity, and aortic valve area (AVA).

Herein we investigated the prevalence and severity of MR in patients with severe AS and its role on the accuracy of the standard echocardiographic parameters of AS quantification.

Of all patients with severe AS undergoing transcatheter or surgical aortic valve replacement enrolled in the German Aortic Registry from 2011 to 2017, 119,641 were included in this study. The population was divided based on the values of left ventricular ejection fraction ([LVEF] > 50%, LVEF 31-50%, and LVEF ≤ 30%] and AVA (0.80 to ≤ 1.00 cm², 0.60 to < 0.80 cm², 0.40 to < 0.60 cm², and 0.20 to < 0.40 cm²).

Overall, 77,890 (65%) patients with mild to-moderate and 4262 (4%) with severe MR were compared with 37,489 (31%) patients without MR. Patients with mild-to-moderate and severe MR presented significantly lower mPG (ΔmPG [95%CI] - 1.694 mmHg [- 2.123 to - 1.265], p < 0.0001 and - 6.954 mmHg [- 7.725 to - 6.183], p < 0.0001, respectively), that increased with LVEF impairment. Conversely, AVA did not differ (severe versus no MR: ΔAVA [95%CI]: - 0.007cm² [- 0.023 to 0.009], p = 0.973). Increasing MR severity was associated with significant mPG reduction throughout all AVA strata, causing a low-gradient pattern, that manifested since the early stages of severe AS (LVEF > 50%: AVA 0.80 to 1.00 cm²; LVEF 31-50%: AVA 0.60 to 0.80 cm²).

In patients with severe AS, concomitant MR is common, contributes to the onset of a low-gradient AS pattern, and affects the diagnostic accuracy of flow-dependent AVA measurements. In this setting, a multimodality, AVA-centric approach should be implemented. In patients with severe aortic stenosis, concomitant mitral regurgitation contributes to the onset of a low-gradient pattern, warranting a multimodality, and AVA-centric diagnostic approach.