A new study presented at the American College of Cardiology's Annual Scientific Session (ACC.26) on Mar. 28 found that using a temporary heart pump and intentionally delaying percutaneous coronary intervention (PCI) for 30 minutes did not significantly reduce heart damage compared to standard immediate PCI in patients experiencing severe heart attacks known as STEMIs.
The research is important because STEMI, a type of heart attack caused by a complete blockage of a major coronary artery, can quickly lead to extensive damage or death if blood flow is not restored rapidly. Current guidelines recommend performing PCI within 90 minutes after arrival at the emergency room, but delays often occur due to late symptom recognition.
Gregg W. Stone said, "In general, the sooner we can get the blocked artery open, the less heart damage the patient will experience." He added that despite rapid angioplasty, many patients still suffer large heart attacks leading to death and heart failure. The trial involved 527 patients across six countries who were randomly assigned either a left-ventricular unloading procedure with a temporary mechanical pump followed by delayed PCI or immediate conventional PCI without pump support.
Magnetic resonance imaging three to five days after treatment showed no significant difference in the extent of heart-muscle damage between groups—30.8% for those with delayed PCI versus 31.9% for those with immediate treatment. Safety data indicated higher rates of major bleeding or vascular complications in patients who received the pump (34%) compared to those who did not (6%). One-year mortality rates were similar between groups.
Stone said further research may be needed: "Of note, in the group that received the heart pump, there was a 47-minute delay before PCI was performed... We would have expected this to increase the extent of heart damage. But we did not see that—if anything, there was slightly less heart damage in the treatment group, although this did not reach statistical significance." He also suggested future studies could examine lowering blood pressure before using such pumps and removing them sooner to reduce complications.
The findings apply only to STEMI patients without cardiogenic shock; previous studies have shown benefits from temporary pumps in shock cases but not among most participants here who had elevated blood pressure instead.
