Comparison of Intracoronary Epinephrine and Adenosine for No-Reflow in Normotensive Patients With Acute Coronary Syndrome (COAR Trial)

Background: Intracoronary epinephrine has been effectively used in treating refractory no-reflow, but there is a dearth of data on its use as a first-line drug in normotensive patients in comparison to the widely used adenosine. Methods: In this open-labeled randomized clinical trial, 201 patients with no-reflow were randomized 1:1 into intracoronary epinephrine as the treatment group and intracoronary adenosine as the control group and followed for 1 month. The primary end points were improvement in coronary flow, as assessed by TIMI (Thrombolysis in Myocardial Infarction) flow, frame counts, and myocardial blush. Secondary end points were in-hospital and short-term mortality and major adverse cardiac events. Results: In all, 101 patients received intracoronary epinephrine and 100 patients received adenosine. Epinephrine was generally well tolerated with no immediate table death or ventricular fibrillation. No-reflow was more effectively improved with epinephrine with final TIMI III flow (90.1% versus 78%, P =0.019) and final corrected TIMI frame count (24±8.43 versus 26.63±9.22, P =0.036). However, no significant difference was observed in final grade III myocardial blush (55.4% versus 45%, P =0.139), mean reduction of corrected TIMI frame count (−25.71±11.79 versus −26.08±11.71, P =0.825), in-hospital and short-term mortality, and major adverse cardiac events. Conclusions: Epinephrine is relatively safe to use in no-reflow in normotensive patients. A significantly higher frequency of post-treatment TIMI III flow grade and lower final corrected TIMI frame count with relatively better achievement of myocardial blush grade III translate into it displaying relatively better efficacy than adenosine. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04699110.