World Congress of Cardiology 2006 - Thrombolytic Therapy, given during cardiopulmonary resuscitation (CPR) in out-ofhospital cardiac arrests, may be no better than placebo.
One of the largest trials ever conducted into the condition was halted early because of the low chance of patients benefiting. However, researchers say thrombolysis may still be considered in some cases.
The Thrombolysis in Cardiac Arrest (TROICA) Trial was due to enrol 1,300 patients in ten European countries. It was stopped by the data safety monitoring board in July 2006, because of the low chance of the drug, tenecteplase, showing superiority over placebo.
By then, 1,050 patients had been included in this randomised, double-blind study. The new analysis was presented at yesterday’s Hot Line II session. It included 827 patients, of whom 412 received tenecteplase and 415, placebo.
The results were unexpected. There was no significant difference in primary or secondary endpoints. Thirty-day survival was 18.2% for the tenecteplase group, compared with 20.2% for placebo (p=0.512). Hospital admission was 59.0% for the treated patients, and 59.5% for the controls (p= 0.931). There was little difference in rates of return of spontaneous circulation, 24-hour survival, and survival to day 30 or hospital discharge.
Adverse events were higher in the treated group, but again, the differences were not significant. Symptomatic intracranial haemorrhage occurred in 1% of the tenecteplase patients, and 0% among controls (p=0.133); major bleeds in 8.9% of the tenecteplase patients versus 7.4% of controls (p=0.528).
Bernd Böttiger (Heidelberg, Germany) led the project: “The results were somewhat disappointing. We had several pilot studies – not done by our group, but by others around the world – that showed benefit with this particular agent during cardiopulmonary resuscitation.”
There had been a strong rationale for the study: up to 70% of out-of-hospital cardiac arrest patients have underlying acute myocardial infarction or pulmonary embolism.
Thrombolytic therapy is indicated for both conditions. Cardiac arrest is associated with systemic coagulation and, again, dissolving clots with thrombolytic therapy was expected to be beneficial.