Intracoronary Administration of Epinephrine and Verapamil in the Refractory No-reflow Phenomenon in Patients With Acute Myocardial Infarction: The EPIVER Randomized Controlled Trial

Primary percutaneous coronary intervention (PPCI) is the preferred reperfusion strategy for treating acute ST-segment elevation myocardial infarction (STEMI). The main goals are to restore epicardial infarct-related artery patency and to achieve microvascular reperfusion as early as possible. No-reflow is the term used to describe inadequate myocardial perfusion of a given coronary segment without angiographic evidence of persistent mechanical obstruction of epicardial vessels and it refers to the high resistance of microvascular blood flow encountered during opening of the infarct-related coronary artery. Despite optimal evidence-based PPCI, myocardial no-reflow can still occur, negating many of the benefits of restoring culprit vessel patency, and is associated with a worse in-hospital and long-term prognosis.

According to clinical guidelines, nitrates, adenosine, platelet IIb / IIIa receptor inhibitors and thrombus extraction can be used to prevent and treat this complication.These methods have demonstrated the ability to improve coronary blood flow in experiment and small clinical trials, however, limiting the zone of myocardial necrosis and improving disease outcomes have not been achieved.

The search for new methods of influencing the pathogenetic links of this complication is urgent. One of the main potentially reversible factors in the pathogenesis of the no-reflow phenomenon, along with microvascular obstruction, is microvascular arteriolar spasm. Thus, this problem of emergency cardiology remains relevant and requires further research, new methods of prevention and treatment.

Aside from exerting beta-1 agonist properties at higher doses and increasing the inotropic and chronotropic stimulation of the myocardium, epinephrine may, at lower doses, exert potent beta receptor agonist properties that mediate coronary vasodilatation. Another drug with a pronounced coronary vasodilation effect is verapamil.

Based on the pharmacodynamic effects of epinephrine and verapamil, it is expected to increase the vasodilating effect when they are used together, due to the additive type of synergistic interaction, which will improve coronary microcirculation after PCI in patients with acute myocardial infarction and refractory no-reflow phenomenon.