ECHO COLOR DOPPLER STUDY DEMONSTRATING AN HIGHER INCIDENCE OF LEFT VS RIGHT RENAL ARTERY STENOSIS IN OLD PEOPLE

INTRODUCTION AND AIMS: Renal vascular pathology is a topic of rising clinical interest and growing therapeutic application (atherosclerosis prevention, percutaneous transluminal renal artery angioplasty and stenting). The aim of this study was to confirm our previous scintigraphic data suggesting a higher incidence of left Renal Artery Stenosis (RAS) Vs the right one. METHODS: 341 nephropathic or hypertensive elderly patients (pts) (219 males, 122 females) mean age 71.7 ± 15.5 (years ± SD) were studied with B mode ultrasound (US) and color Doppler (CD). Renal function was evaluated by determining serum creatinine and glomerular filtration rate (eGFR), calculated using the CKD-EPI formula. The kidney size has been measured by m mode ultrasound. The presence of stenosis has been defined as estimated lumen reduction >50%. RESULTS: Mean serum creatinine levels 1.8 ± 0.9 mg/dl, eGFR 44.1 ± 25.7 ml/min, due to hypertensive or parenchymal renal disease Right Kidney (RK) Longitudinal Diameter (LD) 103.2 ± 12.4 mm (Normal Value -NV)-: 109 ± 12 mm) and Left Kidney (LK) LD (103 ± 12.9 mm - NV: 112 ± 12 mm); that’s to say there is a slight inversion in anatomic size between the kidneys, with a left kidney shrinking for ageing more pronounced in our whole group of nephropathic people. Over 65 years the LK becomes clearly smaller than RK (101.2 ± 13.2 Vs 102.3 ± 12.4 mm) kidney cortical thickness (NV: 16-18 mm) resulted 14.2 ± 3.3 mm on the RK Vs of 13.9 ± 3.3 mm of the LK, confirming a more evident parenchymal loss on this side 100 pts (29%) presented renal artery stenosis with lumen reduction >50%: (in these, 78% interested a single renal artery versus 22% involved both renal arteries) In the subgroups with a single RAS, 31% (24) interested the RKartery and 69% (54) the LK artery, p <0.001 ). Pts with single or bilateral RAS showed more evident reduction in renal function (39.2+21.61) in comparison to pts without any stenosis (46.3 ± 27.04, p = 0.029). We didn’t find any statistically significant functional difference, between pts with single or bilateral stenosis (eGFR 38.5 ± 20.40 and 41.6 ± 25.8 ml/ min respectively p: ns) Index Resistance (IR) presented symmetrically in nephroangiosclerotic pts without any lateral unbalancement in pts without critical RAS. CONCLUSIONS: Our study confirms a higher susceptibility of the left renal artery to develop atherosclerotic stenosis in the elderly. This probably derives from anatomic reasons (first of all the narrower emergency angle) inducing blood flow turbulence and atheroslerosis progression. Peripheral Nephrosclerosis, on the contrary, results a symmetric disease, probably for a predominance of metabolic over reologic causes in atherosclerosis development. The LK seems hence more susceptible to aging progressively loosing both size and function. In over 65 people the RK becomes the predominant one in size and functional performance.