This is a double-blind, multicenter, randomized, placebo-controlled clinical trial. It is planned to enroll patients admitted with anterior ST-segment elevation myocardial infarction (STEMI) within 6h of symptom onset and undergo primary percutaneous coronary intervention (pPCI). Patients who meet the inclusion criteria and without exclusion criteria were randomized 1:1 into the dexmedetomidine (DEX) group or the placebo (saline) group after signing the informed consent. In the DEX group, intravenous injection of DEX was started immediately after enrollment, covering the entire PCI operation, and the administration was stopped at the end of the pPCI. The administration of saline was the same as those in the DEX group. The primary endpoint was the myocardial infarct size (MIS) as assessed by cardiac magnetic resonance imaging (CMR) at 5±2 days post-STEMI. Based on a superiority design and assuming an 20.0% relative infarct size reduction (from 26.0% to 20.8% with a SD of 13.0%), 250 patients are required to be enrolled, accounting for 20% drop-out (α= 0.05 and power= 80%).
Aged 18-75 years old (inclusive);
Diagnosed with anterior STEMI within 6h of symptom onset: (1) ischemic chest discomfort; (2) electrocardiogram (ECG) with ST elevation ≥0.2 mV in 2 or more contiguous precordial leads (one of which should be V2, V3, or V4);
Sign the informed consent form.
Ventricular fibrillation, cardiogenic shock, Killip III-IV grade;
Sinus bradycardia (heart rate sustained <60 beats/min), PR interval> 240ms or II-III degree atrioventricular block;
Continuous systolic blood pressure <120mmHg;
Severe breathing difficulties, aterial blood oxygen saturation <92%;
Parallel
Dexmedetomidine (DEX)
DrugThe patient began to inject DEX intravenously as soon as he enrolled. This study started with the maximum maintenance dose allowed by the label (0.7μg/kg/h). With reference to previous studies, we set 3 pump injection gradients within the range of 0.2-0.7μg/kg/h (0.2μg/kg/h, 0.45μg/kg/h, 0.7μg/kg/h), and based on the patient's heart rate , systolic blood pressure and RASS sedation score to adjust.
Placebo (Saline)
DrugThe patient began intravenous injection of normal saline immediately after enrollment. The administration method and dosage adjustment of normal saline are the same as DEX.
Myocardial infarction size (MIS) evaluated by CMR 5±2 days post-STEMI.
MIS was measured by CMR delayed gadolinium enhancement（expressed as %LV myocardial mass).
Myocardial salvage index (MSI) evaluated by CMR 5±2 days post-STEMI.
MSI defined as: (area at risk - myocardial infarct size) / area at risk × 100.
Microvascular obstruction (MVO) evaluated by CMR 5±2 days post-STEMI.
MVO was evaluated qualitatively on delayed enhanced images; it was defined as hypodense regions within the hyperenhanced infracted area.
Left ventricular ejection fraction (LVEF) evaluated by CMR 5±2 days post-STEMI.
LVEF was defined as: (left ventricular end-diastolic volume - left ventricular end-systolic volume) / left ventricular end-diastolic volume × 100.
The area under curve (AUC) for troponin I (cTnI) and creatine kinase-MB (CK-MB).
Myocardial ischemic injury markers refer to CK-MB and cTnI
The major prespecified safety endpoint: a composite of cardiac death during the first 24 hours after admission.
A composite of cardiac death was defined death from cardiac causes
The major prespecified safety endpoint: II-III degree atrioventricular block during the first 24 hours after admission.
Atrioventricular block is defined as the abnormal conduction of electrical activation between the atria and ventricles during the conduction of electrical activation of the heart, which can lead to arrhythmia and prevent the heart from contracting and pumping blood normally.
The major prespecified safety endpoint:severe sinus bradycardia during the first 24 hours after admission.
Severe sinus bradycardia was defined as heart rate (HR) sustained \<50 beats/min
The major prespecified safety endpoint:severe hypotension during the first 24 hours after admission.
severe hypotension was defined as continuous systolic blood pressure \<80mmHg
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Harbin Medical University
Lead sponsor
Yangtze River Pharmaceutical Group Co., Ltd.
Collaborator
