Background: Atherosclerotic renovascular disease is associated with resistant hypertension and chronic kidney disease, although the causal relationship is discussed. To date, the role of renal artery diameter on these pathological conditions was not clearly studied. We aimed to identify the association of reference diameter and minimal luminal renal artery diameter with glomerular filtration rate (GFR) and resistant hypertension in a high cardiovascular risk population.
Methods: In this cross-sectional, single-center study, we enrolled 734 patients who underwent a renal angiography immediately after a coronary angiography indicated for a diagnosis of ischemic heart disease.
Results: Mean age was 64 ± 10 years (men 72%). GFR was 79 ± 22 ml/min per 1.73 m(2). Five hundred and eighteen patients had no luminal narrowing and 216 patients had low-to-moderate luminal narrowing (10-70%, mean 36%). A positive significant association between reference diameter and GFR was detected in patients without luminal narrowing [beta 2.2 ml/min per 1.73 m(2) for 1 mm increase, 95% confidence interval (CI) 0.3-4.0, P < 0.05] and in those with low-to-moderate luminal narrowing (beta 7.7 ml/min per 1.73 m(2) for 1 mm increase, 95% CI 4.2-11.1, P < 0.001). The lowest quartile of reference diameter (<5.2 mm) was associated with GFR less than 60 ml/min per 1.73 m(2) [odds ratio (OR) 3.18, 95% CI 1.61-6.29, P < 0.001]. Patients with resistant hypertension had low minimal diameter and reference diameter. Reference diameter less than 5.2 mm was associated with an increased risk of resistant hypertension (OR 2.63, 95% CI 1.02-6.77, P < 0.05).
Conclusions: Small renal arteries, defined by a low reference diameter or minimal luminal diameter, are independently associated with low GFR and resistant hypertension, independent of the degree of stenosis and major confounders.