STEMI DTU™: “Unloading Is Not Delaying Treatment” 

“This could be a paradigm-shifting trial in interventional cardiology as we start to think about door-to-unloading as the critical metric, and not just door-to-balloon time,” Vijay Iyer, MD, PhD, FACC, FSCAI emphasizes in this presentation from the 2022 SCAI Scientific Sessions. Dr. Iyer is an associate professor and chief of cardiovascular medicine at Jacobs School of Medicine and Biomedical Sciences, University at Buffalo.

Dr. Iyer explains that the ST-Elevation Myocardial Infarction Door-to-Unloading (STEMI DTU™) pivotal randomized controlled trial (RCT), which is currently enrolling patients, explores whether unloading the left ventricle for 30 minutes with an Impella® heart pump prior to opening blocked arteries will reduce infarct size after a heart attack and lead to a reduction in future heart failure rates.

Explaining the need for this trial, Dr. Iyer states, “For every 5% increase in a myocardial infarct size, the one-year all-cause mortality increases by 19% and the heart failure hospitalization by 20%.” He notes that data going back several decades demonstrates that unloading the ventricle alone can reduce infarct size.

Dr. Iyer presents a case that he enrolled in the STEMI DTU trial, emphasizing that unloading is not delaying treatment. “In the 30-minute waiting period, and we’ve seen this repeatedly in the patients who’ve been randomized to the Impella arm, patients report symptom improvement, we see better hemodynamics and many times we actually sometimes see resolution of the STs as well.” 

He emphasizes the importance of the Impella removal protocol in the study. “We bring all of our Impellas back to the cath lab for removal. We’ve learned that we have been able to minimize the vascular complication rates down to almost 0% by doing that and this is a huge difference from a 4-5% vascular complication rate that we were noticing when the Impella was being removed in the ICU setting.” 

“We as a generation of interventionalists have been raised on the concept of door-to-balloon and we are obsessed with it,” Dr. Iyer concludes. “But I think it’s important to realize that you’re not delaying treatment when you’re unloading these ventricles. And I think at the end of the day our goal is essentially to take these acute MI patients and recover them without heart failure, to reduce the size of the infarct, send them home on good medical therapy and make sure that they have preserved LVs or infarcts that are as small as possible.”

Impella heart pumps are not FDA approved for use in STEMI patients without cardiogenic shock.