Giving a small dose of alteplase, a clot-busting drug, directly into the heart artery during emergency treatment for a major heart attack does not reduce microvascular damage or major adverse cardiac events (MACE), according to a PHRI study.
Shamir Mehta
Findings were presented by Shamir Mehta, principal investigator of the study and PHRI senior scientist, at TCT 2025 and simultaneously published in the Journal of the American College of Cardiology.
Heart attacks caused by ST-segment elevation myocardial infarction (STEMI) occur when a coronary artery becomes completely blocked. Even after the artery is reopened with primary percutaneous coronary intervention (PCI), nearly half of patients experience tiny fragments of clot breaking off and blocking smaller blood vessels, a process called microvascular obstruction, which limits blood flow to the heart muscle and can hinder recovery.
“Microvascular obstruction after primary PCI remains the single most important unresolved issue limiting the efficacy of primary PCI in STEMI patients,” said Mehta.
The STRIVE trial tested whether low-dose intracoronary alteplase could reduce microvascular obstruction or MACE in patients with STEMI and a high clot burden. The multicenter, randomized, double-blind study assigned patients to receive 10 mg or 20 mg of alteplase or placebo (saline) through a specialized catheter after initial blood flow was restored.
A total of 210 patients were randomly assigned to receive the study drug or placebo (68 received alteplase 10 mg, 69 received alteplase 20 mg and 70 were given placebo). MACE, a composite of cardiovascular death, myocardial re-infarction, cardiogenic shock or new onset heart failure at 30 days, occurred in 53.3% in the alteplase group compared to 52.9% in the placebo group.
“STRIVE does not support the routine administration of alteplase and it joins the growing list of previously promising therapies that have not succeeded in improving this important issue.”
The study was funded by the Heart and Stroke Foundation of Canada.
