ST-elevation myocardial infarction (STEMI) occurs when a coronary artery is completely blocked and is the most severe type of heart attack. The STREAM-2 study evaluated the safety of a pharmacoinvasive treatment with half-dose tenecteplase, a clot-busting drug used to prevent death, in STEMI patients aged 60 and older who presented within 3 hours of symptom onset, and were unable to undergo primary percutaneous coronary intervention (PPCI), a procedure used to open a blocked artery, within 1 hour. Patients in the study were randomized to either a Pharmacoinvasive strategy or to timely PPCI.
Since the initial study results demonstrated similar angiographic and clinical 30-day outcomes, except for a higher rate of intracranial bleeding in the pharmacoinvasive arm, partly due to protocol violations like excessive anticoagulation, the researchers performed a prespecified exploratory analysis of mortality and cardiac rehospitalization rates at 1-year.
At 1-year, no significant differences were observed in all-cause or cardiac mortality between the pharmacoinvasive and PPCI groups. Cardiac rehospitalizations were low overall and nominally lower in the pharmacoinvasive group. Patients randomized within 1 hour of symptom onset showed greater benefit from a pharmacoinvasive approach, however, those with anterior infarctions or high TIMI risk scores appeared to have worse outcomes. Treatment delays for both strategies were notably shorter than guideline-recommended targets, which potentially explains the similar 1-year mortality outcomes. The benefit of a pharmacoinvasive strategy was particularly evident in patients treated within 1 hour of symptom onset, aligning with the time-sensitive nature of fibrinolysis and supporting previous 30-day findings. These observations also support a reduction of the current 120-minute guideline recommendations for PPCI delays.
The researchers 1-year findings underscore that a pharmacoinvasive approach using half-dose tenecteplase is a viable option for patients aged 60 and older who present shortly after symptoms begin and are likely to experience substantial delays in accessing PPCI.
This analysis was conducted on behalf of the STREAM-2 Investigators, and CVC co-authors include Paul Armstrong, MD, Robert Welsh, MD, and Kevin Bainey, MD, MSc.
