Compared with immediate PCI alone, the combination of mechanical left ventricular (LV) unloading using a transvalvular micro-axial flow pump (TV-mAFP) plus delayed PCI did not reduce infarct size in patients with anterior STEMI without cardiogenic shock, according to findings from the STEMI-DTU trial presented at ACC.26 and simultaneously published in JACC.

Researchers randomized 527 adults with no prior myocardial infarction from 55 hospitals in the U.S., Germany, Italy, Switzerland, Canada and the UK to receive either LV unloading with a TV-mAFP for 30 minutes prior to PCI or PCI alone. The average age of patients was 61 and about 79% were women.

The primary outcome was infarct size normalized to LV mass evaluated by cardiac magnetic resonance imaging 3-5 days after PCI. The key secondary efficacy endpoint was a composite of death within one year, cardiogenic shock, heart failure, need for a heart transplant, and the extent of heart muscle damage. The key secondary safety endpoint was major bleeding or blood vessel complications within 30 days.

Results showed that the extent of heart-muscle damage was not significantly different across the two groups (30.8% in the TV-mAFP group vs. 31.9% in the control group. The 30-day rate of device-related major bleeding or blood vessel complications was 30.8% in the intervention group, which exceeded the 26.5% pre-defined performance goal.

“Our findings do not support the routine use of a [TV-mAFP] followed by a 30-minute waiting period before performing PCI, as opposed to performing immediate PCI without the heart pump,” said Gregg W. Stone, MD, FACC, co-author of the trial.

In other findings, bleeding rates were significantly higher in the TV-mAFP group compared with the PCI only group (34% vs. 6%), potentially reflecting “prolonged exposure to high dose peri-procedural anticoagulation driven by the protocolized delay to PCI,” the researcher said. Additionally, at one year, 3.6% of patients in the TV-mAFP group had died compared with 5.1% in the control group, a non-statistically significant difference.

While the study did not meet its primary endpoint, Stone said the findings do suggest several avenues for further research. Of note, he said the findings apply only to patients with STEMIs who are not experiencing cardiogenic shock. Use of the same TV-mAFP in a previous study involving patients with both a STEMI and cardiogenic shock significantly reduced the risk of death from any cause within 180 days, compared with similar patients who were not treated with the heart pump.

Stone also added that most patients enrolled in the study had elevated blood pressure, and the type of temporary heart pump used works most efficiently in patients with normal or low blood pressure, pointing to open areas of inquiry. “Pre-treating patients with intravenous medications to lower blood pressure before or shortly after inserting the temporary heart pump could improve the pump’s effectiveness and lead to a greater reduction in heart damage,” he said. “In addition, removing the pump sooner would likely reduce bleeding complications. These changes represent potential avenues for future studies.”

Clinical Topics: Anticoagulation Management, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Stable Ischemic Heart Disease, Vascular Medicine, Acute Heart Failure, Interventions and Vascular Medicine, Chronic Angina

Keywords: ACC Annual Scientific Session, ACC26, New Orleans, Blood Pressure, Percutaneous Coronary Intervention, ST Elevation Myocardial Infarction, Shock, Cardiogenic, Hypotension, Anticoagulants, Hemorrhage, Heart Failure