Late gadolinium enhancement by cardiovascular magnetic resonance heralds an adverse prognosis in nonischemic cardiomyopathy

Abstract

Objectives: We examined whether the presence and extent of late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR) predict adverse outcomes in nonischemic cardiomyopathy (NICM) patients.

Background: Morbidity and mortality is high in NICM patients. However, the clinical course of an individual patient is unpredictable and current risk stratification approaches are limited. Cardiovascular magnetic resonance detects myocardial fibrosis, which appears as LGE after contrast administration and may convey prognostic importance.

Methods: In a prospective cohort study, 65 NICM patients with left ventricular (LV) ejection fraction < or =35% underwent CMR before placement of an implantable cardioverter-defibrillator (ICD) for primary prevention of sudden cardiac death. The CMR images were analyzed for the presence and extent of LGE and for LV function, volumes, and mass. Patients were followed for an index composite end point of 3 cardiac events: hospitalization for heart failure, appropriate ICD firing, and cardiac death.

Results: A total of 42% (n = 27) of patients had CMR LGE, averaging 10 +/- 13% of LV mass. During a 17-month median follow-up, 44% (n = 12) of patients with LGE had an index composite outcome event versus only 8% (n = 3) of those without LGE (p < 0.001 for Kaplan-Meier survival curves). After adjustment for LV volume index and functional class, patients with LGE had an 8-fold higher risk of experiencing the primary outcome (hazard ratio 8.2, 95% confidence interval 2.2 to 30.9; p = 0.002).

Conclusions: A CMR LGE in NICM patients strongly predicts adverse cardiac outcomes. The CMR LGE may represent the end-organ consequences of sustained adrenergic activation and adverse LV remodeling, and its identification may significantly improve risk stratification strategies in this high risk population. (Imaging Techniques for Identifying Factors of Sudden Cardiac Death Risk; NCT00181233).

Figure 1. CMR late gadolinium enhancement patterns seen in the study group

Panel A shows predominantly mid-wall enhancement involving the septal, anterior, and anterolateral walls. Panel B shows apical-lateral near-transmural enhancement (subendocardial to epicardial enhancement). Panel C shows patterns of patchy foci not following an epicardial coronary perfusion territory. In panel C1, there is a focus of mid-lateral wall enhancement. In panel C2, there is basal septal enhancement.

Figure 2

Kaplan-Meier event-free survival curve for the occurrence of an index composite event in patients, grouped by presence or absence of CMR late gadolinium enhancement. Wilcoxon-Breslow p<0.001 for the two survival curves.