The Relationship between Renal Resistive Index and Complexity of Coronary Lesions in Patients with Stable Coronary Artery Diseases

Background : The most common cause of coronary artery diseases (CAD) is atherosclerosis. The synergy between percutaneous coronary intervention with TAXUSTM and cardiac surgery (SYNTAX) score was used to assess complex CAD lesions. The renal resistive index (RRI) is a Doppler ultrasound parameter calculated to assess renal haemodynamics. The direct relationship between CAD complexity and RRI was not yet investigated. The aim of our study was to investigate this relationship between RRI and SYNTAX score in stable CAD patients. Methods : This study included 214 patients with stable CAD and subsequent coronary angiography done at our institution. Regarding CAD complexity, these patients were classified into 166 patients with low SYNTAX score (SYNTAX <= 22), and 48 patients with high SYNTAX score (SYNTAX > 22). The demographic, laboratory, clinical, echocardiographic data and renal Doppler parameters; including RRI, were recorded. Results : Multivariate logistic regression analysis demonstrated that RRI (odds ratio, OR = 4.440, 95% (confidence interval) CI: 1.418-13.903, p = 0.010) was a novel independent predictor of high SYNTAX score in patients with stable CAD, in addition to other traditional predictors as diabetes mellitus (OR = 4.401, 95% CI: 1.081-17.923, p = 0.04), low -density lipoprotein cholesterol (LDL-C) (OR = 2.957, 95% CI: 1.920-8.995, p = 0.027), multi -vessel CAD (OR = 2.113, 95% CI: 1.241-2.280, p = 0.001) and Gensini score (OR = 6.539, 95% CI: 1.977-21.626, p = 0.002). Receiver operator characteristic curve analysis showed that RRI > 0.655 (sensitivity of 80%, specificity of 73.6%) was the best cut-off value for predicting high SYNTAX score. Conclusions : The non -invasively measured RRI is closely associated with high SYNTAX score in stable CAD patients.