The Spectrum of Microvascular Obstruction in Nonischemic Cardiomyopathy

Microvascular obstruction (MVO) is a commonly described complication of coronary reperfusion therapy following a prolonged period of myocardial ischaemia. 1 It is typified by damage and dysfunction of the myocardial microvasculature resulting in a no-reflow phenomenon, where blood flow beyond the myocardial capillary bed is impaired. The emergence of cardiovascular magnetic resonance (CMR) quantitative perfusion mapping has established a robust graded association between left ventricular hypertrophy and microvascular dysfunction. To date, however, MVO as an entity has been underreported outside the setting of acute myocardial infarction. 2 In this vignette, we present CMR imaging examples of MVO in a series of patients with unobstructed coronaries but with left ventricular hypertrophy sufficient to cause structural damage to the microvasculature, resulting in chronic impairment of blood flow to the cardiac myocytes (Figures 1 to 4).

Although the presence of MVO on CMR following acute coronary syndrome is an independent predictor of major adverse cardiovascular events and mortality, 1 further research is needed into whether MVO confers a similarly elevated risk among patients with nonischemic cardiomyopathy.