Prognostic value of echocardiographic-derived stroke volume in severe primary mitral regurgitation.

Aims: Studies have demonstrated the importance of forward flow, and specifically of stroke volume (SV) and SV index (SVI), as prognostic markers in different cardiovascular diseases. In this study, we aim to evaluate the association between SV and SVI thresholds and prognosis in patients with severe primary mitral regurgitation (MR).

Methods and results: The association between either SV (<55, 55-70, and >70 mL) or SVI (<30, 30-35, and >35 mL/m2) thresholds and all-cause mortality and heart failure (HF) hospitalizations was examined in a retrospective analysis of 283 patients [60% male, median age 70 years, interquartile range (IQR) 58-82] with severe primary MR, normal left ventricular size and systolic function, and no other significant left-sided valvular abnormalities. Compared with normal values, SV < 55 mL was found to be associated with worse outcomes (hazard ratio 1.8, IQR 1.1-2.8, P = 0.016), whereas SV between 55 and 70 mL was not. A non-significant trend for worse outcomes was noted for SVI < 35 mL/m2 compared with normal SVI.

Conclusion: In patients with severe primary MR, SV < 55 mL was found to be associated with increased rates of HF hospitalization and all-cause mortality. This easily obtainable parameter may allow for better risk stratification of patients with primary MR.