Effect of Cystatin C Levels on Angiographic Atherosclerosis Progression and Events Among Postmenopausal Women With Angiographically Decompensated Coronary Artery Disease (from the Women’s Angiographic Vitamin and Estrogen [WAVE] Study)

End-stage renal disease and mild renal insufficiency are associated with increased cardiovascular risk. Cystatin C, a novel marker of kidney function, was found to be associated with a higher frequency of cardiovascular events and mortality independent of glomerular filtration rate. It remained uncertain, however, whether enhanced cardiovascular risk associated with cystatin C is due to accelerated progression of atherosclerosis or to plaque instability. The aim of this study was to examine the effects of baseline cystatin C on annual change in coronary artery narrowing and clinical events in 423 postmenopausal women with angiographically documented coronary artery disease enrolled in the Women’s Angiographic Vitamin and Estrogen (WAVE) trial. Baseline and follow-up (mean 2.8 ± 0.9 years) angiography was performed in 320 women. Angiographic progression of disease and clinical events in each cystatin C quartile were compared. Women with cystatin C levels in the highest quartile were older and more likely to have histories of heart failure and stroke. Annualized changes in minimal and average luminal diameters were similar in diseased and nondiseased segments. All-cause death or myocardial infarction (3.6% vs 15.6%, p <0.001), cardiovascular death or myocardial infarction (2.3% vs 13.5%, p <0.001), and cardiovascular events (3.6% vs 13.5%, p <0.001) were significantly higher in women with baseline cystatin C levels in the highest quartile compared with women with cystatin C levels in the lower 3 quartiles. The risk for clinical events associated with cystatin C remained significantly higher in multivariate logistic regression analysis after adjusting for baseline differences and cardiovascular risk factors. The risk for clinical events was also independent of estimated glomerular filtration rate. In conclusion, in postmenopausal women with angiographically documented coronary artery disease, baseline cystatin C levels were associated with worse clinical outcomes without accelerated progression of atherosclerosis.