Circumferential strain acquired by CMR early after acute myocardial infarction adds incremental predictive value to late gadolinium enhancement imaging to predict late myocardial remodeling and subsequent risk of sudden cardiac death.

Abstract

Late adverse myocardial remodeling after acute myocardial infarction (AMI) is strongly associated with sudden cardiac death (SCD). Cardiac magnetic resonance (CMR) performed early after AMI can predict late remodeling and SCD risk with moderate accuracy. This study assessed the ability of CMR-measured circumferential strain (CS) to add incremental predictive information to late gadolinium enhancement (LGE). Patients with an AMI and LVEF < 50% were screened for inclusion. A total of 27 patients, totaling 432 myocardial segments, prospectively underwent CMR 7±5days after percutaneous coronary intervention (PCI). LGE, microvascular obstruction (MVO), and myocardial CS were measured for each segment. The primary endpoint was late segmental adverse remodeling defined as segmental wall motion score (WMS) > 1 measured by echocardiography 3months after PCI. A total of 141 segments experienced the primary endpoint at 3months. The mean LGE volume was higher in these segments, but LGE was also present in many segments with normal WMS (40±28 versus 20±26%, p<0.01). Segments that met the primary endpoint also showed greater impairment of CS. Segments with both LGE > 17% and impaired CS >- 7.2% on CMR were more likely to experience late adverse remodeling (73%) as compared to segments with neither (9%, p<0.001) or one abnormal parameter (36%, p<0.001). CS >- 7.2% also added incremental accuracy to LGE > 17% for predicting late adverse remodeling (AUC 0.81 from 0.70, p<0.001). When performed early after AMI, LGE is a moderate predictor of late remodeling and CS is a powerful predictor of late myocardial remodeling. When combined, they can predict late remodeling, a surrogate of SCD, with high accuracy.