790 left ventricular outflow tract velocity time integral outperforms left ventricular ejection fraction in heart failure patients with significant mitral regurgitation

Abstract Background Reduced left ventricular ejection fraction (LVEF) has been used as a key criterion for the management of mitral regurgitation (MR) in patients with heart failure (HF), including the decision about mitral valve repair. However, LVEF, not taking into account mitral regurgitant volume, may be an imprecise predictor of outcome in HF patients with MR. Conversely, the estimation of the forward volume through the LV outflow tract (LVOT) may be a better metric in this setting. In this regard, LVOT velocity time integral (LVOT-VTI), not relying on geometrical assumptions, has been shown to be more reproducible than the calculated stroke volume (i.e., LVOT-VTI * LVOT cross sectional area), at least in the acute setting. Objective To assess the prognostic significance of LVOT-VTI in a contemporary cohort of patients with chronic HF and significant MR. Methods Consecutive patients with chronic HF with reduced (≤40%) or mildly reduced (41-49%) LVEF and moderate-to-severe or severe MR, according to the latest European Society of Cardiology criteria, were selected and followed-up for the endpoint of cardiovascular death. Results 203 patients were enrolled in the study (74±11 years, 66% men, 47% ischemic etiology, HFrEF 86%, LVEF 31±9%, mean LVOT-VTI 21±6 cm). Most patients showed a NYHA class II (40%) or III (31%) and received beta-blockers (95%), ACE-inhibitors/ARBs or ARNI (77%), and mineralocorticoid receptor antagonists (82%). Seventy-seven patients (38%) had permanent atrial fibrillation and 46 (23%) a cardiac resynchronization therapy device. Over a median follow-up of 18 (7-33) months, 30 patients died, 24 of whom for a cardiovascular cause, and 10 underwent mitral valve repair/replacement. When stratified according to the optimal prognostic cut-off of LVOT-VTI, patients with a LVOT-VTI <16 cm (n=36) showed the greater risk of cardiovascular death (Log Rank 18.2, p<0.001, Figure). Similarly, patients with a LVEF <33% (n=122) showed a higher risk of cardiovascular death (Log Rank 5.5, p=0.019). Nevertheless, at Cox regression analysis, a unit decrease in LVOT-VTI (hazard ratio, HR 0.87 [95%CI 0.79-0.95], p=0.002) but not in LVEF (p=0.729) was associated with a higher risk of cardiovascular death (Figure). Conclusion Left ventricular forward volume, noninvasively estimated through LVOT-VTI, but not LVEF, predicts the risk of cardiac death in patients with chronic HF and significant MR.