A randomized, double-blind, placebo-controlled trial is currently investigating the potential benefits of low-dose dobutamine in patients experiencing acute myocardial infarction (AMI) who are at intermediate to high risk. The study, conducted in Denmark, aims to evaluate whether a 24-hour infusion of dobutamine can improve cardiac function and reduce the levels of pro-brain natriuretic peptide (proBNP), a marker of cardiac stress.
The rationale behind using dobutamine lies in its ability to enhance cardiac contractility and reduce systemic vascular resistance, thereby decreasing left ventricular afterload. While standard dosages for acute heart failure range from 2-3 μg/kg/min up to 20 μg/kg/min, this trial employs a low maintenance dose of 5 μg/kg/min to minimize the risk of tachyarrhythmias in the setting of AMI and to balance vasoconstriction and vasodilation.
Trial Design and Intervention
Eligible patients will be randomized to receive either a 24-hour intravenous infusion of dobutamine at 5 μg/kg/min or a placebo (saline). The infusion is prepared as a weight-standardized solution, administered at a rate of 5 mL per hour, resulting in a total volume of 120 mL. To maintain blinding, the infusions are prepared by a collaborating cardiac unit, ensuring that clinical staff, patients, investigators, and sponsors remain unaware of the treatment assignment. The infusion is initiated as early as possible after informed consent, but no later than 2 hours after percutaneous coronary intervention (PCI).
The protocol allows for a reduction in the dobutamine/placebo infusion rate to 2.5 μg/kg/min if persistent tachyarrhythmia occurs (ventricular rate ≥ 130/min for > 30 min). The treating physician also has the discretion to modify or halt the dobutamine infusion if deemed necessary.
Endpoints and Assessments
The primary endpoint of the trial is the between-group difference in peak proBNP levels within 48 hours from randomization. Secondary endpoints include assessments of acute and follow-up hemodynamic function via transthoracic echocardiography (TTE), differences in pulse rate and blood pressure within 48 hours, proBNP levels at three-month follow-up, and changes in troponin T, lactate, and CK-MB levels at various time points after infusion.
Sample Size and Recruitment
The trial aims to enroll 100 patients to account for dropouts and missing data. The recruitment period is estimated to last three years, based on historical data from previous studies conducted at the center.
Concomitant Care and Post-Trial Provisions
The trial intervention is designed to supplement current standard guidelines for the treatment of AMI patients, with no expected delays or restrictions on concomitant care or interventions. Patients participating in the study are covered by the Danish Patient Compensation Scheme. After the final follow-up visit, any observed clinical indicators of new or worsening diseases will be assessed and referred for appropriate management.
