A potential evidence to explain the reason behind the devastating prognosis of coronary artery disease in uraemic patients: renal insufficiency is associated with poor coronary collateral vessel development.

The potential of individuals to develop coronary collateral circulation is often neglected but is of potential major importance in myocardial vulnerability. Likewise, the effect of chronic kidney disease (CKD) on collateral vessel development is not known. The purpose of this study was to evaluate the effect of CKD on collateral development in patients with advanced coronary artery disease. A total of 171 uraemic patients (serum creatinine > or = 1.5 mg/dl, creatinine clearance < 80 mL)/min) who underwent coronary angiography were evaluated in this study. A total of 134 patients met the criteria for the uraemic group and 134 consecutive non-uraemic patients who constituted the control group. The collateral score (CS) was graded according to the Rentrop classification and the collateral score was calculated by summing the Rentrop numbers of every patient. Collateral vessels have also been categorized according to their anatomic locations and collateral connection grades (CC). CC2 collaterals were observed less frequently in the uraemic patients than in the control subjects (11% versus 26%, p=0.03) and CC0 more frequently (31% versus 22%, p<0.05). Epicardial pathway was detected more frequently in the control subjects than in the uraemic patients (31% versus 12%, p=0.03) and septal pathway less frequently (37% versus 54%). There was a significant negative correlation between CS and creatinine (r=-0.68, p<0.01). The mean CS in the uraemic group was significantly lower than the non-uraemic group (1.29+/-0.88 versus 2.18+/-1.3, p<0.001). These results altogether showed that besides the quantity, quality (functional, haemodynamic and anatomic features) of the uraemic collaterals and a network that they constitute is also impaired and different from the collaterals of the patient with normal renal function.