Background: Cardiac magnetic resonance (CMR) is considered the reference standard for assessment of left ventricular ejection fraction (LVEF) and myocardial damage. However, few studies have evaluated the relationship between CMR findings and patient outcome, and of these, most are small and none multicenter. We performed an international, multicenter study to assess the prognostic importance of routine CMR in patients with known or suspected heart disease.
Methods and results: From 10 centers in 6 countries, consecutive patients undergoing routine CMR assessment of LVEF and myocardial damage by cine and delayed-enhancement imaging (DE-CMR), respectively, were screened for enrollment. Clinical data, CMR protocol information, and findings were collected at all sites and submitted to the data coordinating center for verification of completeness and analysis. The primary end point was all-cause mortality. A total of 1560 patients (age, 59±14 years; 70% men) were enrolled. Mean LVEF was 45±18%, and 1049 (67%) patients had hyperenhanced tissue (HE) on DE-CMR indicative of damage. During a median follow-up time of 2.4 years (interquartile range, 1.2, 2.9 years), 176 (11.3%) patients died. Patients who died were more likely to be older (P<0.0001), have coronary disease (P=0.004), have lower LVEF (P<0.0001), and have more segments with HE (P<0.0001). In multivariable analysis, age, LVEF, and number of segments with HE were independent predictors of mortality. Among patients with near-normal LVEF (≥50%), those with above-median HE (>4 segments) had reduced survival compared to patients with below- or at-median HE (P=0.02).
Conclusions: Both LVEF and amount of myocardial damage as assessed by routine CMR are independent predictors of all-cause mortality. Even in patients with near-normal LVEF, significant damage identifies a cohort with a high risk for early mortality.