Background: The FRISC-II trial was the first randomised trial to show a reduction in death or myocardial infarction with an early invasive versus a non-invasive treatment strategy in patients with non-ST-elevation acute coronary syndrome. Here we provide a remaining lifetime perspective on the effects on all cardiovascular events during 15 years' follow-up.

Methods: The FRISC-II prospective, randomised, multicentre trial was done at 58 Scandinavian centres in Sweden, Denmark, and Norway. Between June 17, 1996, and Aug 28, 1998, we randomly assigned (1:1) 2457 patients with non-ST-elevation acute coronary syndrome to an early invasive treatment strategy, aiming for revascularisation within 7 days, or a non-invasive strategy, with invasive procedures at recurrent symptoms or severe exercise-induced ischaemia. Plasma for biomarker analyses was obtained at randomisation. For long-term outcomes, we linked data with national health-care registers. The primary endpoint was a composite of death or myocardial infarction. Outcomes were compared as the average postponement of the next event, including recurrent events, calculated as the area between mean cumulative count-of-events curves. Analyses were done by intention to treat.

Findings: At a minimum of 15 years' follow-up on Dec 31, 2014, data for survival status and death were available for 2421 (99%) of the initially recruited 2457 patients, and for other events after 2 years for 2182 (89%) patients. During follow-up, the invasive strategy postponed death or next myocardial infarction by a mean of 549 days (95% CI 204-888; p=0·0020) compared with the non-invasive strategy. This effect was larger in non-smokers (mean gain 809 days, 95% CI 402-1175; p_interaction=0·0182), patients with elevated troponin T (778 days, 357-1165; p_interaction=0·0241), and patients with high concentrations of growth differentiation factor-15 (1356 days, 507-1650; p_interaction=0·0210). The difference was mainly driven by postponement of new myocardial infarction, whereas the early difference in mortality alone was not sustained over time. The invasive strategy led to a mean of 1128 days (95% CI 830-1366) postponement of death or next readmission to hospital for ischaemic heart disease, which was consistent in all subgroups (p<0·0001).

Interpretation: During 15 years of follow-up, an early invasive treatment strategy postponed the occurrence of death or next myocardial infarction by an average of 18 months, and the next readmission to hospital for ischaemic heart disease by 37 months, compared with a non-invasive strategy in patients with non-ST-elevation acute coronary syndrome. This remaining lifetime perspective supports that an early invasive treatment strategy should be the preferred option in most patients with non-ST-elevation acute coronary syndrome.

Funding: Swedish Heart-Lung Foundation, Swedish Foundation for Strategic Research, and Uppsala Clinical Research Center.