Unloading the Left Ventricle Before Reperfusion in Patients With Anterior ST-Segment-Elevation Myocardial Infarction

Area of Science:

• Cardiology
• Interventional Cardiology
• Acute Myocardial Infarction Research

Background:

• ST-segment-elevation myocardial infarction (STEMI) infarct size directly impacts heart failure and mortality.
• Preclinical studies indicate mechanical left ventricular (LV) unloading before reperfusion reduces infarct size and activates cardioprotective pathways.
• The DTU-STEMI trial is the first to explore the safety and feasibility of LV unloading and delayed reperfusion in STEMI patients without cardiogenic shock.

Purpose of the Study:

• To assess the safety and feasibility of mechanical left ventricular (LV) unloading using the Impella CP device in patients with anterior STEMI.
• To evaluate the impact of a 30-minute LV unloading period followed by reperfusion on infarct size compared to immediate reperfusion.
• To determine if LV unloading prior to reperfusion is a safe strategy in STEMI patients.

Main Methods:

• A multicenter, prospective, randomized exploratory safety and feasibility trial involving 50 anterior STEMI patients.
• Patients were assigned to either immediate reperfusion (U-IR) or delayed reperfusion after 30 minutes of LV unloading (U-DR) using Impella CP.
• The primary safety endpoint was a composite of major adverse cardiovascular and cerebrovascular events at 30 days; infarct size was assessed by cardiac MRI.

Main Results:

• All 50 patients completed their assigned protocols (U-IR, n=25; U-DR, n=25) with mean door-to-balloon times of 72 and 97 minutes, respectively.
• No statistically significant difference in major adverse cardiovascular and cerebrovascular event rates between the U-IR (8%) and U-DR (12%) groups (P=0.99).
• Delayed reperfusion after 30 minutes of LV unloading did not significantly affect 30-day mean infarct size compared to immediate reperfusion (13% vs. 15% LV mass, P=0.53).

Conclusions:

• Mechanical LV unloading with the Impella CP device, followed by a 30-minute delay before reperfusion, is feasible in anterior STEMI patients within a reasonable timeframe.
• The DTU-STEMI pilot trial did not reveal safety concerns that would prevent larger pivotal studies.
• Further investigation in a powered pivotal trial is necessary to compare LV unloading before reperfusion against the current standard of care for STEMI treatment.