Abstract
We read with interest the study by Uysal et al 1 evaluating the association between serum uric acid (SUA) level and coronary collateral circulation (CCC) in patients with stable coronary artery disease (CAD).
Several studies reported a relationship between SUA and CCC in acute coronary syndrome 2–4 but none had previously addressed stable CAD. As a simple, widely available noninvasive marker, SUA is a useful indicator of inflammation and oxidative stress that have been studied in several cardiovascular diseases. 5–7 So, for the first time, Uysal et al 1 demonstrated a relationship between SUA level and CCC in stable CAD. However, the study has limitations.
First, the study lacks data regarding some of the components of metabolic syndrome like dyslipidemia and waist circumference which correlate with SUA levels. 8,9 Second, the study has no data regarding cardiovascular medications. Among these drugs, the beneficial effects of statins are not only due to the improvement in plasma lipid levels but also due to the action on the vasculature including the improvement in endothelial function, anti-inflammatory, and antithrombotic actions. 10,11 Animal studies have shown that statins promote angiogenesis and CCC development. 12,13 However, there are conflicting data in clinical trials. 14,15 Another study 16 reported that the dosage and duration of statin therapy (≥10 mg atorvastatin-equivalent dose for > 3 months) were associated with enhanced CCC. Also, there have been several reports on the SUA-lowering effect of statins, 17,18 which may impact on the study results. Third, renal function has not been reported in the study. Impaired renal function has effects on both the SUA levels and the poor CCC development. 19
In conclusion, Uysal et al 1 showed that higher SUA levels were associated with poor CCC in stable CAD, but these results should be interpreted with some limitations.