Dexrazoxane linked to 68% less heart-muscle bleeding after severe heart attacks

The artery is open, but the heart muscle can still be bleeding. That is the problem targeted by the phase 2 SHIELD-MI trial at Indiana University School of Medicine, where adults with severe heart attacks received intravenous dexrazoxane before, during and after emergency angioplasty. In the final comparison, the drug was associated with a 68% reduction in intramyocardial hemorrhage (IMH), bleeding inside the heart muscle.

The mechanism matters because reopening the artery is only the first step. Reperfusion—the return of blood flow—can leave small vessels injured, allowing red blood cells to leak into the myocardium, or heart muscle. The Indiana team used cardiac magnetic resonance imaging (CMR) 48 to 72 hours after the procedure to measure hemorrhage, infarct size, microvascular injury and left ventricular function.

SHIELD-MI enrolled 123 STEMI patients, but its final analytic cohort contained 50 clinically matched participants: 25 received dexrazoxane and 25 received a placebo. The treatment group showed a 34% reduction in infarct size and higher left ventricular ejection fraction. The researchers reported no serious adverse events, and the trial’s findings were presented at ESC Congress 2026 in Munich and published in the European Heart Journal.

And so, concretely, the potential benefit is a drug already used in oncology being tested at a precise moment in emergency heart care: immediately before primary PCI, then at four, eight and 12 hours afterward. If larger studies confirm the signal, cardiology teams could have a way to limit damage that continues after the blocked artery has been reopened, potentially reducing later heart failure or death for patients with STEMI.

The limits are clear. SHIELD-MI was a single-center, double-blind, placebo-controlled sequential-cohort trial, and its results measure early heart injury rather than proven long-term survival. The study supports further investigation; it does not yet establish dexrazoxane as standard treatment.