Diagnostic relevance of angiography-derived coronary microcirculatory resistance in sudden cardiac death

Background: Obstructive coronary disease remains a leading cause of sudden cardiac death (SCD). The management of SCD therefore involves coronary angiography. Our aim was to evaluate whether the non-hyperemic angiography-derived microcirculatory resistance index (NH-IMRangio) could be an easy-to-use tool for identifying patients with electrical heart disease (EHD) from patients with other causes of SCD. Methods: A retrospective study was carried out on 30 patients who survived from SCD with no significant coronary lesions on coronary angiography. Etiological investigations enabled the classification of patients with myocardial disease (Group 1, n=20) and those with EHD without myocardial disease (Group 2, n=10). Myocardial disease was investigated by cardiac magnetic resonance imaging (CMR). NH-IMRangio was determined based on standard coronary angiographic views with 3-dimensional-modeling and computational analysis of the coronary flow. Results: Patients were 46.4±15.9 years old and mostly male (73%). Group 1 included patients with dilated cardiomyopathy (n=7), non-dilated left ventricular cardiomyopathy (n=6), hypertrophic cardiomyopathy (n=2), arrhythmogenic right ventricular cardiomyopathy (n=1), myocardial infarction with non-obstructive coronary arteries (MINOCA) disease due to vasospastic angina (n=1), myocarditis (n=2), chemotherapy-induced cardiomyopathy (n=1). Group 1 presented a significantly higher NH-IMR angio compared to group 2 (46.5±13.1 vs. 34.1±10.8, P