Association of Preoperative Cardiac Magnetic Resonance and Echocardiography with Post-Operative Left Ventricular Dysfunction in Primary Mitral Regurgitation.

Abstract

Background: We evaluated the relationship between preoperative left ventricular (LV) structural and functional characteristics assessed by echocardiography (Echo) and cardiac magnetic resonance (CMR), and the risk of post-operative left ventricular (LV) dysfunction in patients with primary mitral regurgitation (MR) undergoing mitral valve (MV) repair surgery.

Methods: We retrospectively studied 223 patients (median age 60 years, 21% women) with chronic primary MR who underwent preoperative Echo and CMR before MV repair surgery. The primary endpoint was post-operative LV dysfunction, defined as LV ejection fraction (EF) < 50% on follow-up Echo.

Results: Post-operative LV dysfunction occurred in 41 patients (18%) after a median follow-up of 8.7 [IQR: 6.7-12.5] months. These patients had higher absolute and indexed (ind) LV end-systolic diameters (ESD) and volumes (ESV) (all p≤0.009), lower CMR-LVEF (p=0.003), and a trend towards lower Echo-LVEF (p=0.072). Individually, Echo and CMR parameters showed modest discriminative ability (areas under the curve from 0.59 [0.49-0.68] for Echo-LVEF - to 0.70 [0.61-0.78] for Echo-indLVESD). Strain imaging, whether assessed by Echo or CMR, did not improve risk stratification. Echo-indLVESD and CMR-LVEF were the most contributive LV characteristics. A two-step approach based on Echo-indLVESD < or ≥ 18 mm/m², followed by CMR-LVEF > or ≤ 56% in patients with Echo-indLVESD ≥ 18 mm/m², identified three subgroups with distinct rates of post-operative LV dysfunction (9%, 20% and 41%, respectively).

Conclusion: In patients with primary MR undergoing MV surgery, preoperative LV characteristics assessed by Echo and CMR showed only moderate ability to identify those at higher risk of post-operative LV dysfunction. A stepwise approach using Echo-indLVESD followed by CMR-LVEF may help identify subgroups at differing risk levels. These exploratory findings require confirmation in larger prospective studies.