March 28, 2026 — Randomized controlled trial (RCT) data presented at the American College of Cardiology (ACC) 2026 and simultaneously published in the Journal of the American College of Cardiology demonstrates for the first time that supporting the left ventricle (LV) with an Impella CP for more than 40 minutes prior to reperfusion does not reduce nor increase heart muscle damage, known as a myocardial infarction. Greater infarct size correlates to a higher risk of dying or developing heart failure, a condition that impacts more than 55 million worldwide1. Findings from the trial support future studies on whether pre-PCI treatment with Impella CP opens a window of time that enables delivery of adjunct pharmacotherapies designed to reduce reperfusion injury.
STEMI DTU (ST-segment Elevation Myocardial Infarction Door-To-Unloading) RCT2 is a mechanistic study investigating the impact of LV unloading on infarct size. The overall findings are neutral because the trial’s primary endpoint did not demonstrate that LV support plus delayed reperfusion reduces heart muscle damage in patients with anterior STEMI without cardiogenic shock compared with PCI alone. The hypertensive nature of most anterior STEMI patients enrolled in the study may have limited the ability of Impella CP to reduce LV wall stress and unload the LV, thereby contributing to the neutral results.
“This is a landmark trial with novel insights that will impact future scientific discovery for years,” said Gregg Stone, MD3, Professor of Medicine and Director of Academic Affairs for the Mount Sinai Health System, co-Principal Investigator, and presenter of the study at ACC 2026. “STEMI-DTU challenges the standard STEMI treatment paradigm that is focused only on rapid coronary reperfusion, a directive that has not changed in the last three decades. While this trial was neutral, the results raise intriguing possibilities about potential therapeutic approaches that combine mechanical circulatory support and pharmaceutical therapy.”
Other novel findings from the study include:
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Older patients enrolled in the study (61+ years of age) demonstrated a trend towards reduced infarct size with LV support and delayed PCI (p=0.056). Over 75% of STEMI patients in the U.S. are over age 654.
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Higher rates of bleeding and vascular complications in the treatment arm were not associated with increased mortality at 12 months.
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Compared to controls, pre-PCI TIMI blood flow was significantly improved after 30 minutes of Impella CP support and corresponded to an increase in coronary perfusion pressure. Coupled with 100% operator compliance with the treatment protocol, these observations suggest a period of patient stability on Impella CP support prior to revascularization that informs future clinical trials.
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Elevated lactate levels were correlated with larger infarct sizes across the total study population. This finding provides new insight into the clinical utility of a pre-PCI lactate level to identify patients at higher risk, despite clinical stability.
“STEMI DTU is the first clinical trial to test this novel and disruptive hypothesis and demonstrate the ability to stop the ischemic clock during infarct. More research is needed in older age, abnormal lactate subsets and the impact of concomitant beta blockade. We will continue to explore LV unloading impact without PCI in STEMI patients in future studies,” said William O’Neill, MD2, emeritus director of the Center for Structural Heart Disease at Henry Ford Health System and co-Principal Investigator of the study.
“During the period between Impella CP insertion and PCI, operators could bail out and perform PCI at their discretion based on patient stability. However, there was never a clinical need to begin PCI during this waiting period. We had 100% compliance. Many of my patients began to snore, suggesting that they were clinically stable enough to fall asleep. This suggests that pre-PCI LV unloading rested the heart without worsening the infarction,” said Nima Aghili, MD, MPH2, Interventional Cardiology, Advanced Heart Failure Specialist, Colorado Heart and Vascular and participating clinician in the study.
For more information, please visit www.jnjmedtech.com/en-US/.
1 World Heart Federation
2 STEMI DTU Randomized Control Trial is a Johnson & Johnson sponsored study
3 Drs. Stone, O’Neill and Aghili were not compensated for their participation in this press release
4 Salari, N., Morddarvanjoghi, F., Abdolmaleki, A., Rasoulpoor, S., Khaleghi, A. A., Hezarkhani, L. A., Shohaimi, S., & Mohammadi, M. (2023). The global prevalence of myocardial infarction: a systematic review and meta-analysis. BMC cardiovascular disorders, 23(1), 206. https://doi.org/10.1186/s12872-023-03231-w
March 27, 2026 
