Comparing treatment options for patients with coronary artery disease and diabetes

This study compared the outcomes of two interventional procedures for multivessel coronary artery disease, coronary artery-bypass grafting (CABG) and percutaneous coronary intervention (PCI) in patients with diabetes mellitus (DM).

Coronary artery disease (CAD) is a condition caused by the narrowing of the blood vessels that supply the heart (coronary arteries). This is the result of a process called atherosclerosis; the accumulation of fatty deposits within artery walls. Two interventional procedures can be used to restore blood flow to the heart muscle, CABG or PCI. CABG is a major surgery in which a healthy artery or vein is used to bypass the blocked portion of the artery. In PCI, a catheter is inserted into the artery, with a balloon at the tip. The balloon inflates to widen around the blockage; afterwards a stent (flexible tube) can be placed at the blocked site to support the artery and keep it open. Diabetic patients often have extensive atherosclerosis, which leads to a multivessel CAD, meaning that many coronary arteries are sick and narrowed. In such patients, CABG used to be the treatment of choice. Today, PCI has evolved to include different types of stents, some can release a drug that prevent re-clogging of the stent, referred to as drug-eluting stents (DES). The present study compared the benefits of CABG versus PCI using DES for diabetic patients with a multivessel CAD.

This study included 1900 diabetic patients with a mulivessel CAD. Patient were randomly assigned to undergo either CABG or PCI with a drug-releasing stent. Patients were followed for up to 6.75 years following their procedure; three main outcomes were documented: death, nonfatal heart attack (not resulting in death), or nonfatal stroke. 

After 5 years, 26.6% of patients who underwent PCI had either outcome, significantly more than the 18.7% of CABG patients. This benefit for CABG patients is due to their lower risk of death or heart attack; they did have a higher rate of stroke than did the PCI patients.

In summary, for patients with multivessel CAD and DM, CABG leads to more satisfactory long-term outcomes than PCI: it reduced the rates of death and heart attack, but not the rate of stroke.

CABG is a major surgery that involves a high rate of short-term morbidity (illness) and mortality (death) and slow recovery. In contrast, PCI is a non-surgical procedure, with less risks in the short-term, but higher long-term complications such as stent restenosis (blockage of the stent) that may lead to a heart attack.

Accordingly, a well-planned study that compares these two interventions, should better choose the outcomes, i.e. both short and long-term cardiovascular morbidity and mortality. Death from any cause (that can be unrelated to the procedure), and nonfatal heart attacks and strokes may not be the best choice of outcomes for such comparison.    

If you have diabetes and CAD and intend to undergo PCI or CABG, discuss with your doctor the pros and cons of each procedure, considering the extent of your CAD.