Unloading the Left Ventricle Before Reperfusion in Patients with Anterior ST-Segment Elevation Myocardial Infarction: A Pilot Study Using the Impella CP®

Author Department

Cardiology; Medicine

Document Type

Article, Peer-reviewed

Publication Date




In ST-elevation myocardial infarction (STEMI), infarct size correlates directly with heart failure and mortality. Preclinical testing has shown that compared with reperfusion alone, mechanically unloading the left ventricle (LV) before reperfusion reduces infarct size and in addition, that 30 minutes of unloading activates a cardioprotective program that limits reperfusion injury. The Door-To-Unload in STEMI Pilot Trial represents the first exploratory study testing whether LV unloading and delayed reperfusion in patients with STEMI without cardiogenic shock is safe and feasible.


In a multi-center, prospective, randomized exploratory safety and feasibility trial, we assigned 50 patients with anterior STEMI to LV unloading using the Impella CP followed by immediate reperfusion (U-IR) versus delayed reperfusion after 30 minutes of unloading (U-DR). The primary safety outcome was a composite of major adverse cardiovascular and cerebrovascular events (MACCE) at 30 days. Efficacy parameters included assessment of infarct size using cardiac magnetic resonance (CMR) imaging.


All patients completed the U-IR (n=25) or U-DR (n=25) protocols with respective mean door-to-balloon times of 72 versus 97 minutes. MACCE rates were not statistically different between the U-IR versus U-DR groups (8% vs. 12%, respectively, p=0.99). Compared with the U-IR group, delaying reperfusion in the U-DR group did not affect 30-day mean infarct size measured as a percent of LV mass (15±12% vs. 13±11%, U-IR vs. U-DR, p=0.53).


We report that LV unloading using the Impella CP device with a 30 minute delay before reperfusion is feasible within a relatively short time period in anterior STEMI. The DTUSTEMI pilot trial did not identify prohibitive safety signals that would preclude proceeding to a larger pivotal study of LV unloading before reperfusion. An appropriately powered pivotal trial comparing LV unloading before reperfusion to the current standard of care is required.