Abstract 562: A New Method for Evaluating Renal Artery Stenosis and Coronary Artery Disease by Multislice Computed Tomography
(Background) Renal artery stenosis (RAS) is most frequently due to atherosclerosis and is associated with coronary artery disease (CAD) and aortic atheroma. Recently multislice computed tomography (MSCT) has remarkably progressed and it is recommended for noninvasive diagnosis of RAS. Variable pitch helical scanning (VPHS) method can scan cardiac (narrow pitch, ECG gated) and abdominal (wide pitch, non ECG gated) area within one scanning. Thus this method enables us to screen CAD and RAS noninvasively at a time. The aim of this study was to investigate the frequency of RAS using VPHS with MSCT and to find the predictors for RAS.
(Methods) Consecutive 354 patients (male 57%, mean age 67 y.o.) who were suspected of CAD and planned for MSCT (Aquilion 64, Toshiba Medical Systems) were enrolled in this study. VPHS method was used in all patients. The patients with renal insufficiency (serum creatinine > 1.5mg/dl) were excluded. Traditional risk factors and estimated creatinine clearance (eCcr) calculated by the Cockcroft-Gault formula were analyzed. According to the maximum aortic atheroma thickness, patients were classified into 3 groups. (normal: <2mm, moderate: 2– 4mm, severe: 75% stenosis or severe calcification, and RAS was defined as >50% stenosis.
(Results) Renal artery was clearly shown in 96% of the patients (contrast amount 0.9ml/kg, radiation exposure 25mSv). CAD was identified in 152 patients (45%) and number of stenotic vessel was 1 in 21%, 2 in 15% and 3 in 8%. RAS was found in 26 patients (8%) (Right; 16, Left 18, Both 8). When patients were classified into 2 groups with and without RAS, there was a significant difference in age, gender, refractory hypertension required ≥ 3 drug classes of antihypertensives, eCcr, CAD, number of stenotic vessel and aortic atheroma between 2 groups. Finally, multivariate analysis showed that number of stenotic vessel (per 1 vessel, OR 1.9, 95%CI 1.1– 4.2, P=0.04), and moderate or severe atheroma (OR 3.8, 95%CI 1.1–15.8, P=0.03; OR 14.3, 95%CI 3.7–71.4, P<0.0001, respectively) were independently associated with RAS.
(Conclusions) MSCT with VPHS system was an excellent modality to identify both CAD and RAS. Multivessel CAD or aortic atheroma was the independent predictor for RAS.