STEMI-DTU Trial: LV Unloading Before PCI Fails to Reduce Infarct Size in Anterior STEMI Without Shock
The STEMI-DTU trial, presented at ACC.26 and published in JACC, has indicated that mechanical left ventricular (LV) unloading using a transvalvular micro-axial flow pump (TV-mAFP) combined with delayed percutaneous coronary intervention (PCI) did not decrease infarct size in patients with anterior ST-elevation myocardial infarction (STEMI) who were not experiencing cardiogenic shock.
The STEMI-DTU trial indicated that mechanical left ventricular (LV) unloading using a transvalvular micro-axial flow pump (TV-mAFP) combined with delayed percutaneous coronary intervention (PCI) did not decrease infarct size in patients with anterior ST-elevation myocardial infarction (STEMI) who were not experiencing cardiogenic shock.
Study Overview
The multi-country study involved 527 adult participants, none with a prior history of myocardial infarction, across 55 hospitals. Participants were randomly assigned to one of two groups: either receiving LV unloading with a TV-mAFP for 30 minutes before PCI, or undergoing immediate PCI alone. The average age of the patients was 61 years, with approximately 79% being women.
Key Findings: No Reduction in Infarct Size
The primary outcome, infarct size normalized to LV mass, was assessed by cardiac magnetic resonance imaging (CMR) 3-5 days post-PCI. Results showed no significant difference in heart muscle damage between the two groups. The infarct size was reported as 30.8% in the TV-mAFP group versus 31.9% in the control group.
Results showed no significant difference in heart muscle damage between the two groups (30.8% in the TV-mAFP group versus 31.9% in the control group).
Safety Outcomes: Bleeding Concerns Highlighted
Regarding safety, the 30-day rate of device-related major bleeding or blood vessel complications in the intervention group was 30.8%, which exceeded the pre-defined performance goal of 26.5%. Bleeding rates were notably higher in the TV-mAFP group compared to the PCI-only group, at 34% versus 6% respectively.
A researcher suggested that this increase in bleeding could be attributed to prolonged exposure to high-dose peri-procedural anticoagulation stemming from the protocolized delay to PCI. One-year mortality rates were 3.6% in the TV-mAFP group and 5.1% in the control group, a difference that was not statistically significant.
Expert Commentary and Future Directions
Gregg W. Stone, MD, FACC, a co-author of the trial, commented that the findings do not support the routine use of a TV-mAFP with a 30-minute waiting period before PCI, as opposed to immediate PCI without the pump.
Gregg W. Stone, MD, FACC, co-author of the trial, stated that the findings do not support the routine use of a TV-mAFP with a 30-minute waiting period before PCI, as opposed to immediate PCI without the pump.
Dr. Stone also outlined several areas for future research. He emphasized that these findings apply specifically to STEMI patients without cardiogenic shock. He noted that a previous study using the same TV-mAFP in patients with both STEMI and cardiogenic shock showed a significant reduction in death within 180 days.
Future studies could explore ways to improve pump effectiveness, such as pre-treating patients with intravenous medications to lower blood pressure, given that most study participants had elevated blood pressure and the pump operates more efficiently at normal or low blood pressure. Additionally, Dr. Stone suggested that removing the pump sooner might help reduce bleeding complications.