The role of microvascular obstruction and intramyocardial hemorrhage in reperfusion injury to the heart

Abstract

Microvascular obstruction (MVO) of coronary arteries promotes an increase in mortality and major adverse cardiac events in patients with acute myocardial infarction (AMI) and percutaneous coronary intervention (PCI). Intramyocardial hemorrhage (IMH) is observed in 41–50 % of patients with ST-segment elevation myocardial infarction and PCI and is accompanied by inflammation. There is evidence that microthrombi are not involved in the development of MVO, which is associated with infarct size, the duration of ischemia, and myocardial edema. However, there is no conclusive evidence that the latter plays an important role in the development of MVO. There is evidence that platelets, inflammation, Ca2+ overload, neuropeptide Y, and endothelin-1 could be involved in the pathogenesis of MVO. The role of endothelial cell dysfunction in MVO formation in patients with AMI and PCI remains under question. It is unclear whether nitric oxide production is decreased in patients with MVO. It was obtained only indirect evidence on the involvement of inflammation in the development of MVO. The role of reactive oxygen species, necroptosis and pyroptosis in the pathogenesis of MVO is also not studied. The participation of thromboxane A2, vasopressin, and prostacyclin in the formation of MVO is unknown. It was not obtained conclusive evidence on the involvement of coronary artery spasm in the development of MVO. Dual antiplatelet therapy improves the efficacy of PCI in prevention of MVO. It is unknown whether epinephrine or L-type Ca2+-channel blockers improves coronary blood flow in patients with MVO.