AIM: This investigation was aimed at comparing the results of doppler examination with those of angiography (AGX), of the computed tomographic angiography (CTa), and the angiographic nuclear magnetic resonance (MRa) for the screening of critical (>60%) renal artery stenosis (RAS). The study evaluated also the relation between RAS, the renal dysfunction and the cardiovascular outcome; in patients that underwent renal PTA/stenting we evaluated the effects of the procedure on renal function.
METHODS: among the 1072 hypertensives examined between 2001 and 2013 RAS was diagnosed by Doppler according to the corrected Strandness and Fortune criteria: proxymal renal artery peak systolic velocity - PSV> 200 cm/sec; renal aortic velocity ratio - RAR >3.5; interlobular acceleration time AT >80msec. All follow-up informations (cardiovascular clinical outcome; effects of the diagnosis on therapy - medications vs PTA) were collected by phone.
RESULTS: a RAS was detected in 99 patients (9%); 25 underwent further investigation (AGX, CTa, MRa). AGX and US data were consistent (positive RAS test) in 8/9 patients; MRa and US in 5/6 patients; CTa and US in 14/16, with a 88,9, 83,3 and 87,5% agreement respectively. A >200 cm/s PSV proved to be the most reliable diagnostic parameter since it was present in all patients with a positive AGX or CTa. An elevated (>0.80) hilar resistive index and a <1.00cm cortical thickness were the strongest death predictors and were beyond the normal limits in all patients that had died by the end of the follow up. In 44,4% of the patients treated with renal PTA/stenting serum creatinine dropped an average 8.63% (from >1.2 to <1.2 mg/dl; p= 0,021, χ²).
CONCLUSIONS: Renal PSV is the best doppler parameter to diagnose RAS; an elevated RI (>0.80) is related with a poorer clinical outcome. The PTA/stenting can improve renal function in some patients.
