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.