Prediction of Post-operative Left Ventricular Dysfunction in Patients with Severe Mitral Regurgitation

Background: Surgical repair of mitral regurgitation (MR) results in reduction in left ventricular (LV) stroke volume secondary to cessation of retrograde flow and may lead to LV dysfunction. LV ejection fraction (EF) and LV end systolic dimension (ESD) are used to determine the timing of surgery, however they are suboptimal predictors of post-operative LV dysfunction.

Objective: To evaluate the value of quantitative parameters of MR severity as a predictors of LV dysfunction (LVEF<50%) after MV repair.

Methods: We evaluated 83 patients with severe, degenerative MR undergoing MV repair. Quantitative parameters of MR severity included effective regurgitant orifice area (EROA) and regurgitant volume (RVol). RVol >80ml or EROA >0.6cm² were classified as a very severe MR.

Results: Of 83 patients, 39 (47%) had RVol>80%. Pre-operative EF was comparable between RVol>80% and RVol≤80ml patients (p=0.54). RVol >80ml patients compared to those with RVol ≤80ml demonstrated lower post-operative EF (47±9% vs 52%±10, p=0.009), and higher prevalence of LV dysfunction (64% vs 43%, p=0.031)

EROA>0.6 cm² was observed in 40 (48%) of patients. Pre-operative EF was similar in EROA>0.6cm² and EROA≤0.6cm² patients (p=0.6). Patients with EROA>0.6 cm² compared to patients with EROA≤0.6cm² showed an insignificant trend towards a lower post-operative EF (48% vs. 51%, p=0.065) and a more frequent LV dysfunction (60% vs. 46.5%, p=0.013).

In multivariate analysis RVol rejected EROA and, along with EF, was an independent predictors of post-operative LV dysfunction (p<0.001, p=0.52, and p

Conclusion: Very severe MR defined as an RVol>80ml is associated with post-operative LV dysfunction after MV repair. This parameter may be helpful in asymptomatic patients for decision making regarding timing of surgery.