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

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 postoperative 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 end point was postoperative LV dysfunction, defined as LV ejection fraction (LVEF) <50% on follow-up Echo.

RESULTS

Postoperative LV dysfunction occurred in 41 patients (18%) after a median follow-up of 8.7 (interquartile range, 6.7-12.5) months. These patients had higher absolute and indexed (ind-) LV end-systolic diameters (LVESDs) and volumes (LVESVs; all P ≤ .009), lower CMR LV ejection fraction (LVEF; P = .003), and a trend toward lower Echo LVEF (P = .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 2-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 3 subgroups with distinct rates of postoperative 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 postoperative 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.