Prevalence and Predictors of Renal Artery Stenosis (RAS) in Coronary Artery Disease (CAD) Patients Undergoing Coronary Angiogram (CAG)

INTRODUCTION: The true prevalence of atherosclerotic renal artery stenosis (ARAS) is higher than the number reported because of the lack of specific clinical symptoms and signs and lack of appropriate guidelines for evaluation of ARAS. Early identification of ARAS helps in preventing the renal and cardiovascular morbidity and mortality. There is sparse available Indian literature about the occurrence of ARAS in CAD individuals. This study intends to study the percentage and predictors of ARAS in CAD individuals undergoing CAG in Government Stanley Hospital, Chennai. Identifying clinical risk factors would enable stratifying patients and identifying those patients in whom screening renal angiography would be indicated. AIMS AND OBJECTIVE: 1. To determine the prevalence of significant RAS in patients with CAD. 2. Correlation between severity of CAD and RAS. 3. To determine the predictive factors associated with RAS. The predictive factors studied are age, gender, smoking, hypertension, diabetes mellitus, hypercholestrolemia, preprocedure serum creatinine and extent of CAD. MATERIALS AND METHODS: Source of Data: A sample of 100 CAD patients admitted for CAG in Government Stanley Hospital, Chennai during the period June 2012 to November 2012. Type of Study: Observational study. Inclusion Criteria: 1. Suspected CAD was by ECG, Echo or TMT criteria. 2. Creatinine clearance>60ml/min(By Cockroft and Gault equation). 3. Renal size of more than 9 cm on sonogram. Exclusion Criteria: 1. Known case of RAS. 2. Presence of single kidney. 3. Known case of Chronic kidney disease. RESULTS: In the study, renal angiogram was done for100 CAD patients who underwent CAG, to look for the presence of atherosclerotic renal artery stenosis, the location and number of RAS sites involved. Out of the 100 patients screened, 11 patients had no significant CAD, 22 patients had single vessel disease, 31 patients had double vessel disease and 36 patients had between triple vessel disease. The patients in the study were aged between 42 and 70 years. 11 patients were aged between 42- 50 years, 55 patients 51- 60 years and 34 patients between 61- 70 years. In our study all patients found to have were above age 60 years. CONCLUSIONS: The true clinical occurrence of RAS is more than that reported. • Early identification of patients having RAS can help to early institution of treatment and hence prevention of long term complications and better prognosis. • In our study, age> 60 years (p=0.001), creatinine clearance (p=0.001), lipid profile (p=0.002), serum creatinine (p=0.005), extent of CAD (p=0.0080) were observed to be significantly associated with ARAS at 0.01 level of significance. • Male gender, hypertension, diabetes mellitus, smoking were observed to be other independent risk factors. • The logistic regression was obtained to be: Probability (patient having RAS) = 1/(1+exp(-(-102.247 + (0.655*Age) + (21.371*Serum Creatinine) + (0.354*Creatinine Clearance) + (6.022*Lipid Profile) + (3.927* Extent Of CAD) + (4.327 * Hypertension)). It was observed that if probability (patient having RAS) > 0.5, patients were at a more risk of having RAS