401Prognostic role of late gadolinium enhancement in patients with low-intermediate 5 year HCM SCD risk score: a multicenter study

Abstract

Background: Hypertrophic cardiomyopathy (HCM) is a familiar disease with a heterogeneous clinical expression and variable prognosis. Sudden cardiac death (SCD) is the most life-threating complication of HCM. Nowadays, cardiac magnetic resonance (CMR) is affirmed as fundamental imaging technique for diagnosis of HCM and for not invasive detection of myocardial fibrosis, expressed as late gadolinium enhancement (LGE). ESC Guidelines suggest the implantation of a ICD in primary prevention according to a 5-year Risk SCD score >=6%. Unfortunately when the Risk SCD score is intermediate there is not a clear recommendation for therapeutic strategy. Purpose(s): The aim of the study is to evaluate the prognostic role of LGE in a population with a low-intermediate 5-year Risk SCD score according to the current ESC Guidelines. Method(s): From 2008 to 2017 patients with HCM underwent a consecutive CMR scan. This study was multicenter investigation, including data from 5 hospitals. The examination was performed using 1.5 Tesla systems with cardiac phased array multichannel coil. LGE images were acquired 10 min after the administration of Gd-DTPA with a dosage of 0.2 mmol/kg for the short axis views. The extent of LGE was measured using a previously validated method (1) and expressed in percentage of LV mass. The 5-years Risk SCD score was calculated in entire population and patients with an intermediate-low Risk SCD score <6% were enrolled in the study. At follow up hard cardiac events included SCD, resuscitated cardiac arrest, appropriate ICD shock, adequate anti-tachycardia pacing, sustained ventricular tachycardia on Holter electrocardiogram monitoring. Result(s): The final population of the study comprised of 354 patients with 5-year ESC risk SCD score <6% (257 males, age 54+/-17). Two hundred and thirty (65%) patients were positive for LGE at visual assessment. Episodes of hard cardiac events occurred in 22 patients; LGE was detected in a high proportion (92%) of patients who experienced of a malignant arrhythmic event. The worst prognosis was found in patients with extreme LV hypertrophy (p=0.04), higher indexed LV mass (p=0.034) and higher extent of myocardial fibrosis (p=0.002), while, based on HCM risk SCD score, no differences between the group with cardiac events and those without were detected (p=0.6). Based on the logistic regression analysis, LGE extent was the best independent predictor of hard cardiac events (HR 1.05; 95% CI 1.03-107; p<0,0001) and at Kaplan-Meier curves patients with LGE >10% had a worst prognosis than those with lower extent (p<0.0001). Conclusion(s): This is the first manuscript that demonstrates as the extent of LGE is able to recognize additional patients at increased risk for malignant arrhythmic episodes in a population with low-intermediate 5-year ESC risk SCD score.