As body mass index (BMI) increases, the likelihood that atherosclerosis will progress after coronary artery bypass grafting (CABG) also rises, US researchers report. However, aggressive statin therapy may eliminate this association.
Prior research has established obesity as a clear and major risk factor for heart disease, but whether it also affects disease progression post-CABG was unclear, Dr. Christine C. Wee, from Beth Israel Deaconess Hospital in Boston, and colleagues point out.
The researchers addressed this question in 1314 subjects enrolled in the Post CABG trial, which looked at the effects of warfarin and statin therapy following heart surgery. Of the subjects, 254 had a BMI of 30 to 34.9 (class I obesity) and 68 had a BMI of 35 or higher (class II or III).
Angiographic evaluation at 4 to 5 years post-CABG revealed a direct link between BMI and the odds of atherosclerotic progression, according to the report in the Journal of the American College of Cardiology for August 19. Higher BMI, however, did not correlate with an elevated risk of clinical events.
In patients on low-dose lovastatin (2.5 to 5 mg/day), class I obesity and class II or III obesity increased the odds of disease progression by 1.34- and 2.97-fold, respectively (p for trend = < 0.001).
By contrast, obesity was not significantly tied to progression in patients taking high-dose lovastatin (40 to 80 mg/day). In fact, with high-dose lovastatin on board, there was a suggestion that higher BMI actually protected against clinical events (p = 0.06).
The results, the researchers conclude, suggest that "aggressive treatment with (lovastatin) and potentially with other statins may reverse the adverse effect of obesity on coronary artery disease progression. Future studies should examine whether the larger benefits of statins in obese persons generalize to those without pre-existing coronary disease."
J Am Coll Cardiol 2008;52:620-625.
