Extent of Coronary and Myocardial Disease and Benefit From Surgical Revascularization in LV Dysfunction

Study Questions:

What is the impact of anatomic variables associated with poor prognosis on the effect of coronary artery bypass grafting (CABG) in ischemic cardiomyopathy?

Methods:

This was a secondary analysis of the STICH (Surgical Treatment for Ischemic Heart failure) trial. Patients had coronary artery disease (CAD) and ejection fraction (EF) of <35%, and were randomized to receive CABG plus medical therapy or optimal medical therapy (OMT) alone. The authors focused on three prognostic factors: presence of three-vessel CAD, EF below the median (27%), and end-systolic volume index above the median (79 ml/m2). Patients were categorized as having 0-1 or 2-3 of these factors.

Results:

Patients with 2-3 prognostic factors (n = 636) had reduced mortality with CABG compared to those who received OMT (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.56-0.89; p = 0.004); CABG had no such effect in patients with 0-1 factor (HR, 1.08; 95% CI, 0.81-1.44; p = 0.591). There was a significant interaction between the number of factors and the effect of CABG on mortality (p = 0.022). Among patients randomized to medical therapy alone, there was a significantly higher mortality in patients with 2-3 prognostic factors than in those with 0-1 factor (p < 0.001), but a difference was not observed among patients randomized to CABG (p = 0.190).

Conclusions:

The authors concluded that among patients with ischemic cardiomyopathy, the survival benefit of CABG is limited only to those with more extensive anatomical disease.

Perspective:

Surgical revascularization is commonly recommended for patients with severe CAD and low EF, although the overall results of the STICH trial did not demonstrate a survival benefit. This substudy demonstrates that the survival benefit of CABG is limited to those with the most extensive disease (although the early hazard is greater in this group). This suggests that CABG for survival benefit should be restricted to this group of patients, and for those with less extensive disease, it would only be indicated for relief of angina.

Keywords: Coronary Artery Disease, Cardiomyopathies, Coronary Artery Bypass, Angioplasty, Balloon, Coronary


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