Prevalence, Correlates, and Prognostic Relevance of Mid-Wall Late Gadolinium Enhancement in Patients With Ischemic Cardiomyopathy

Background. Late gadolinium enhancement (LGE) imaging is an established cardiac magnetic resonance (CMR) technique for the assessment of myocardial replacement fibrosis. The presence of mid-wall LGE has been described in ~30% of patients with non-ischemic dilated cardiomyopathy and is known to be associated with poor outcome. Conversely, little is known regarding the clinical significance of mid-wall LGE in patients with ischemic cardiomyopathy (ICM). Therefore, the aim of the present study was to investigate the prevalence, correlates and prognostic role of mid-wall LGE in a consecutive cohort of patients with ICM. Methods and Results. A total of 319 consecutive outpatients with ICM (mean age 64±11 years, 87% males) enrolled in the UHSM CMR Study (ClinicalTrials.gov NCT02326324) were included. All patients had CMR with LGE imaging and were followed for a median of 13 months (25th–75th percentiles, 6–28 months). The outcome end-point was a composite of cardiovascular death, aborted sudden cardiac death, appropriate implantable cardioverter-defibrillator therapy, heart failure hospitalisations, implantation of left ventricular (LV) assist device or occurrence of heart transplant. At CMR with LGE imaging, mean LV ejection was 37±9%, mean ischemic-type LGE expressed as % of LV mass was 16±9%, while mid-wall LGE was observed in 32 (10%) patients. LVEDV index (OR 1.02, 95% CI 1.01-1.03, p = 0.001) and LV sphericity index (OR 1.04, 95%CI 1.01-1.07, p = 0.024) were the only variables significantly and independently related to the presence of mid-wall LGE. The outcome end-point was documented in 37 (12%) patients. Ischemic-type LGE expressed as % of LV mass (HR 1.04, 95% CI 1.01-1.08; p = 0.015) and the presence of mid-wall LGE (HR 4.5, 95% CI 2.2-9.2; p < 0.001) were the only independent predictors of the composite outcome. Furthermore, mid-wall LGE had significant incremental predictive value compared to the extent of ischemic-type LGE (Dχ2 = 16.5, p <0.001). Conclusions. Mid-wall LGE is observed in a substantial minority of patients with ICM. In this population, the presence of mid-wall LGE is associated with adverse LV remodeling and worse prognosis, independently from the extent of ischemic-type LGE.