Management of Acute Coronary Syndromes in Patients with Diabetes: Implications of the FREEDOM Trial

Background

Diabetes mellitus (DM) is a powerful independent risk factor for multivessel, diffuse coronary artery disease (CAD). The optimal coronary revascularization strategy in DM is not clearly defined, but past trials have suggested an advantage for coronary artery bypass grafting (CABG). Recently, the Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease (FREEDOM) trial found patients randomized to CABG had lower rates of death and myocardial infarction (MI) compared with those randomized to percutaneous coronary intervention (PCI).

Objective

This article reviews the contemporary management of patients with DM presenting with acute coronary syndromes, particularly ST-elevation MI, in the post-FREEDOM era.

Methods

We undertook a comprehensive review of published literature addressing trials in this field performed to address current knowledge both in the pre- and post-FREEDOM era.

Results

The implications of FREEDOM for patients with acute coronary syndrome are that CABG provides a significant benefit, compared with PCI with drug-eluting stents, to patients with DM and multivessel coronary artery disease; and that patients similar to those enrolled in FREEDOM should receive CABG in preference to PCI. The relevance of FREEDOM’s findings to the large proportion of patients who would not meet inclusion criteria—including patients with an acute coronary syndrome undergoing an early or emergent invasive strategy, remains uncertain.

Discussion

FREEDOM’s outcomes have generated uncertainty regarding best practice once thrombolysis in myocardial infarction grade 3 flow is re-established in patients with DM and multivessel disease. Current interventional guidelines recommend optimally treating the culprit artery; however, decisions made at the time of revascularization influence future revascularization strategies, particularly stent choice and resultant P2Y₁₂ receptor antagonist therapy. The preferred method for future revascularization may be questioned if the patient's residual coronary stenoses do not, post-PCI, meet the FREEDOM inclusion criteria, or where the left anterior descending artery is the infarct-related artery, and after left anterior descending artery PCI the patient would not receive an internal mammary graft. The management of residual disease and the preferred (further) revascularization strategy needs to be tested in an appropriately powered randomized trial.

Conclusions

The optimal revascularization strategy in patients with acute coronary syndrome, diabetes, and multivessel disease, in particular those with ST elevation, is unclear, and not guided by level A (or B) evidence. Currently CABG is favored over PCI, and an individually tailored, collaborative approach, guided by a multidisciplinary heart team, should be employed.