Invasive compared with non-invasive treatment in unstable coronary-artery disease: FRISC II prospective randomised multicentre study Original Research Article

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% Cl 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.