Hypertrophic cardiomyopathy (HCM), the most common genetic disease of the myocardium, is characterized by extreme diversity with regard to phenotypic expression and clinical course. Extent and distribution of left ventricular (LV) hypertrophy as well as the functional manifestations of the disease are heterogeneous. Clinically, HCM is the most common cause of sudden cardiac death in the young, but also a substrate of heart failure (HF) at any age. Coronary microvascular dysfunction (CMD) is a common feature in HCM leading to altered myocardial perfusion and reduced coronary flow reserve and represents an independent predictor of unfavourable outcome in HCM patients.
HCM is characterized by a severe alteration of cardiac architecture and function, involving cardiomyocytes and coronary microvessels. Microvascular remodelling consists in vessel wall thickening, due to medial smooth muscle hypertrophy/proliferation and collagen deposition with different degrees of intimal thickening and perivascular fibrosis.
Morphologic and in situ expression studies are necessary to shed light on the pathogenic mechanism of microvascular remodelling.
Coronary microvascular dysfunction (CMD) is a mechanism of myocardial ischemia in patients with left ventricular dysfunction (LVH) and normal epicardial coronary arteries. Chronic CMD and ischemia lead to replacement fibrosis and contribute to disease progression towards LVD and heart failure (HF) both in arterial hypertension (AH) and in hypertrophic cardiomyopathy (HCM). This accounts for an increased cardiovascular morbidity and mortality even in patients