Initiate Danhong Injection before or after percutaneous coronary intervention for microvascular obstruction in ST-elevation myocardial infarction (DIRECTION): Study protocol for a randomized controlled trial

Background: No treatment has convincingly been proven to be beneficial for microvascular obstruction (MVO) in patients with ST-elevation myocardial infarction (STEMI). Several studies have described the effects of Danhong Injection. However, evidence of a rigorously designed verification study is still lacking, and the intervention timing of Danhong Injection is uncertain. Methods: The DIRECTION study is a multicenter, prospective, randomized, evaluator-blind study. A total of 336 patients with STEMI receiving percutaneous coronary intervention (PCI) will be randomly assigned to conventional treatment, the preoperative Danhong Injection, or the postoperative Danhong Injection. The primary outcome is rate of ST-segment resolution (STR) ≥ 70% at 90 min after PCI. The secondary outcomes are the degree of STR, Thrombolysis in Myocardial Infarction (TIMI) flow grade, TIMI myocardial perfusion grade, left ventricular ejection fraction, N-terminal prohormone brain natriuretic peptide, high-sensitivity C-reactive protein, and infarct size expressed as area under the curve for cardiac troponin I (cTnI) and for creatine kinase MB. The major adverse cardiovascular events and hospital readmission events will be recorded. Health quality will be assessed with the 12-item Short Form Health Survey. The safety outcomes include bleeding events, adverse events, and abnormal changes in routine blood tests. Psychological status and dietary patterns will be evaluated using Hamilton Depression Rating Scale and Food Frequency Questionnaire as the relevant indicators. Discussion: This trial will evaluate the efficacy and safety of Danhong Injection, as well as its optimal timing of intervention to prevent MVO in patients with STEMI. Trial registration: Chinese Clinical Trial Registry, ChiCTR1900021440. Registered on February 21, 2019.