“(T)he last decade taught us that invasive therapy reduces adverse ischemic events, including early and intermediate death, myocardial infarction, or urgent revascularization for unstable angina,” Bavry concluded. “Future research will need to refine the lowest risk patients who are appropriate for conservative therapy.”

Despite the important differences between the three trials in terms of inclusion criteria, study design, treatment methods and recruitment periods, which might have contributed to the differing results, the studies “reported comparable long-term mortality in patients treated by selective invasive and routine invasive strategies,” Dr. Robert Henderson of Nottingham University Hospitals in the UK told Reuters Health by email.

Moreover, he added, the trials all reported higher rates of the combined endpoint of death or MI in the routine invasive arm, which, ICTUS suggests, is due to procedure-related MI, which nonetheless “did not translate into an excess mortality over 10-15 years follow-up.”

The combined evidence from these three trials, Dr. Henderson said, “raises questions about the widespread use of the routine invasive strategy in the majority of patients with non-ST-segment elevation myocardial infarction, many of whom may not benefit substantially from invasive treatment.”

On the other hand, he continued, interventional practice has evolved substantially since these trials recruited patients and now includes, for example, second generation drug-eluting stents and novel antiplatelet regimens. Therefore, “it is possible that the results of a routine invasive strategy will have improved over the last decade,” though such a strategy is associated with risks and costs.

“An invasive approach is indicated in patients with hemodynamic instability or with persistent or recurrent myocardial ischemia, but for patients who remain stable after a single episode of ischemia, the role of routine invasive treatment is less certain, particularly if risk assessment suggests that the patient is at low risk of recurrent cardiovascular events,” concluded Dr. Henderson, who was not involved with ICTUS.

The trial was supported by the Interuniversity Cardiology Institute of the Netherlands, the Working Group on Cardiovascular Research of the Netherlands, and educational grants from Eli Lilly, Sanofi/Synthelabo, Sanofi, Pfizer, and Medtronic.