Effect of Chronic Pretreatment with β-Blocker on No-Reflow Phenomenon in Diabetic Patients with Acute ST-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Abstract

Coronary no-reflow is a serious complication of PCI which is caused by microvascular obstruction. Microvascular obstruction may result from downstream distal embolization of particulate material from the epicardial coronary artery, as well as from in situ microvascular and myocardial tissue injury. Microvascular obstruction leads to myocardial ischemia and is associated with adverse clinical outcome and increased mortality. B-blockers could protect the myocardium through the inhibition of the apoptosis and provide theoretical basis for the clinical prevention and therapy of no-reflow. The purpose of this study was to investigate the possible role of chronic B-blocker therapy in the prevention of the no-reflow phenomenon in diabetic patients with acute ST-elevation myocardial infarction undergoing primary PCI. The study included 107 diabetic patients who had presented with acute STEMI within 12 hours from the onset of chest pain, during the period from February 2015 to September 2015. The patients were randomized according to their previous treatment with oral beta blocker; 50 patients were on oral Beta blocker for at least 6 months before, and 57 patients who were not on oral Beta blocker therapy. All the patients underwent primary PCI at Ain Shams university hospitals or National Heart institute. Our study showed that the incidence of no-reflow phenomenon in the present study was 21%. No-reflow phenomenon was significantly lower in patients on chronic B-blocker therapy (12% vs. 28%; P = 0.04). The heart rate was significantly lower in the normal reflow group than in the no-reflow group (P = 0.03). The study also showed that B-blocker pretreatment is an independent protective predictor for the no-reflow phenomenon (P=0.045), while increased heart rate was significantly associated with occurrence of no-reflow phenomenon (P=0.009). The limited number of patients could limit the strength of the study.