Invasive compared with non-invasive treatment in unstable coronary-artery disease: FRISC II prospective randomised multicentre study. FRagmin and Fast Revascularisation during InStability in Coronary artery disease Investigators.

BACKGROUND: In unstable coronary-artery disease early invasive procedures are common, despite lack of evidence for the superiority of this approach. We compared an early invasive with a non-invasive treatment strategy in unstable coronary-artery disease.

METHODS: In a prospective randomised multicentre study, we randomly assigned 2457 patients in 58 Scandinavian hospitals (median age 66 years, 70% men) an early invasive or non-invasive treatment strategy with placebo-controlled long-term low-molecular-mass heparin (dalteparin) for 3 months. Coronary angiography was done within the first 7 days in 96% and 10%, and revascularisation within the first 10 days in 71% and 9% of patients in the invasive and non-invasive groups, respectively. We followed up patients for 6 months. Analysis was by intention to treat.

FINDINGS: After 6 months there was a decrease in the composite endpoint of death or myocardial infarction of 9.4% in the invasive group, compared with 12.1% in the non-invasive group (risk ratio 0.78 [95% CI 0.62-0.98], p=0.031). There was a significant decrease in myocardial infarction alone (7.8 vs 10.1%, 0.77 [0.60-0.99]; p=0.045) and non-significantly lower mortality (1.9 vs 2.9%, 0.65 [0.39-1.09]; p=0.10). Symptoms of angina and re-admission were halved by the invasive strategy. Results were independent of the randomised dalteparin treatment. The greatest advantages were seen in high-risk patients.

INTERPRETATION: The early invasive approach should be the preferred strategy in most patients with unstable coronary-artery disease who have signs of ischaemia on electrocardiography or raised biochemical markers of myocardial damage.