IRIS-MAIN Evaluates Differential Event Rates for Treatments of Unprotected Left Main CAD Patients

July 24, 2017—Findings from the Interventional Research Incorporation Society-Left Main Revascularization registry (IRIS-MAIN) were recently published online by Se Hun Kang, MD, et al in Circulation: Cardiovascular Interventions.

This large, international, multicenter registry evaluated differential event rates and independent predictors of long-term major cardiovascular events and death in 5,795 patients with unprotected left main coronary artery disease (CAD) who were treated with stents, bypass surgery, or medication. Identifying predictive factors for events in these patients is of great clinical value for risk stratification and possible guidance for tailored preventive strategies, advised the investigators.

The treatment strategies for patients in the registry were percutaneous coronary intervention (PCI) (n = 2,850), coronary artery bypass grafting (CABG) (n = 2,337), and medication alone (n = 608). The investigators analyzed the incidence and independent predictors of major adverse cardiac and cerebrovascular events (MACCEs), which was a composite of death, myocardial infarction, stroke, and repeat revascularization, as well as all-cause mortality in each treatment stratum.

As summarized in Circulation: Cardiovascular Interventions, during follow-up (median, 4.3 years), the rates of MACCEs and death were substantially higher in the medication group than in the PCI and CABG groups (P < .001).

In the PCI group, the three strongest predictors for MACCEs were chronic renal failure, age 65 years or older, and previous heart failure; those for all-cause mortality were chronic renal failure, older age, and low ejection fraction.

In the CABG group, age 65 years or older, chronic renal failure, and low ejection fraction were the three strongest predictors of MACCEs and death.

In the medication group, age 65 years or older, low ejection fraction, and diabetes mellitus were the three strongest predictors of MACCEs and death.

These findings demonstrated that among patients with unprotected left main CAD, the key clinical predictors for MACCEs and death were generally similar regardless of index treatment. This study provides effect estimates for clinically relevant predictors of long-term clinical outcomes in real-world left main CAD patients, providing possible guidance for tailored preventive strategies, concluded the investigators in Circulation: Cardiovascular Interventions.