Clinical significance of low-grade renal artery stenosis

Background. Patients with a renal artery stenosis (RAS) > 50% carry an increased risk for future cardiovascular (CV) events. Experimental literature on this topic suggests that this might as well be true for subjects with lower-grade RAS. Methods. Recruitment in this longitudinal cohort study was conducted from 1982 to 2002 in a Dutch University Hospital. Included in this study were 301 hypertensive patients clinically suspected of having RAS. Study participants were radiologically classified as having no, a low-grade (< 50% lumen narrowing) or high-grade (>= 50%) RAS. A predetermined composite CV end-point was defined as one of the following: myocardial infarction or 'objectified' angina pectoris, ischaemic stroke or death from any CV cause. Other end-points were the occurrence of CV complications, all-cause plus CV mortality and decline in renal function. Results. During a median follow-up of 8.2 years, the incidence of the composite end-point totalled 79 events. After full adjustment in Cox models, a significant risk increase in high-grade [hazard ratio (HR) 2.81; P = 0.002] and low-grade RAS (HR 2.32; P = 0.038) was observed. Other end-points did not differ significantly between study groups. Conclusion. Hypertensive subjects with RAS of any extent, compared with hypertensives without RAS, carry a substantially increased risk for future CV events. Therefore, even in patients with low-grade RAS, aggressive pharmacological treatment strategies should be adopted as a preventive measure.