Abstract
BACKGROUND: Knowledge remains limited regarding the relationship between cardiac magnetic resonance (CMR) preoperative characteristics and postoperative clinical outcomes in primary mitral regurgitation (MR). OBJECTIVES: The authors assessed the prognostic value of CMR preoperative characteristics in patients with primary MR due to prolapse or flail undergoing mitral valve surgery. METHODS: We retrospectively studied 284 patients (median age 61 years, 24% women) with chronic significant primary MR, who underwent CMR and echocardiography (echo) prior to mitral valve repair surgery. The endpoint was a composite of all-cause mortality, hospitalization for heart failure, stroke, or life-threatening ventricular arrhythmia. RESULTS: Over a median follow-up of 7.3 years (Q1-Q3: 3.4-10.5), adverse events occurred in 36 (13%) patients. CMR-left atrial emptying fraction (LAEF) (HR: 1.84 [95% CI: 1.32-2.56]; P < 0.001), CMR-right ventricular ejection fraction (HR: 1.36 [95% CI: 1.00-1.84]; P = 0.047), and CMR-indexed aortic forward stroke volume (HR: 1.40 [95% CI: 0.99-2]; P = 0.059) were each associated with a higher risk of adverse outcomes (HR for decrease in 1 SD). After adjusting for clinical and imaging risk factors, reduced CMR-LAEF remained independently associated with adverse prognosis (adjusted HR: 1.78 [95% CI: 1.27-2.48]; P < 0.001). Patients with CMR-LAEF <30% had higher 5-year event rates (28% vs 4%; P < 0.001) and were at a substantially higher risk of adverse outcomes (adjusted HR: 3.78 [95% CI: 1.83-7.80]; P < 0.001), with added prognostic value confirmed by multiple performance model metrics. CONCLUSIONS: In patients with primary MR, among CMR and echo preoperative characteristics, reduced CMR-LAEF, with a threshold value of 30%, is markedly associated with an increased risk of postoperative adverse outcomes.