Difference between renal and splenic resistive index as a novel criterion in Doppler evaluation of renal artery stenosis

Abstract

Detection of renal artery stenosis (RAS) using Doppler is difficult to evaluate, particularly under conditions such as bilateral RAS or difficultly accessible renal arteries (RA). The objective of the present study was to assess the utility of splenic arterial compared to renal flow as an additional parameter in the Doppler evaluation of RAS. The difference between the resistive indices (RI) determined in renal and splenic parenchymal arteries (ΔRIK−S) was evaluated in 181 hypertensive subjects without any evidence of RAS. Subsequently 47 RA in 24 patients with suspected RAS were angiographically assessed. A ΔRIK−S of 0.055 (median) was determined in the population without any evidence of RAS similar to RA with angiographically excluded stenosis (ΔRIK−S 0.068). In contrast, in angiographic proven RAS, ΔRIK−S was significantly lower (−0.050; P < .005). The assessment of the ΔRIK−S, proved to be an easily feasible parameter, which improves the diagnostic accuracy in the detection of RAS.

Splenic Doppler Resistive Index Variation Mirrors Cardiac Responsiveness and Systemic Hemodynamics upon Fluid Challenge Resuscitation in Postoperative Mechanically Ventilated Patients

“…The large variability of spleen volume in adult humans makes the simple evaluation of spleen size unreliable for hemodynamic assessment. The only parameter validated and described in various contexts for this purpose is the SDRI because it is easier to measure and shows a better defined diastolic phase if compared with other splanchnic arteries (i.e., superior mesenteric artery) [ 11 , 17 , 18 ]. In addition, SDRI provides information on downstream arterial vascular resistance, with the consequent possibility of detecting hemodynamic abnormality related to organ dysfunction before biochemical and macrohemodynamic changes.…”

“…In clinical practice, the measurement of the spleen size is commonly used even if it represents only an indirect method to assess splenic circulation and its clinical application is limited by wide interindividual variability. Splenic Doppler resistive index (SDRI) can provide a more direct and less variable assessment of splenic circulation [ 11 ] without requiring estimates of Doppler angle or vessel cross-sectional area. Moreover, SDRI is independent of perfusion pressure and is increased by hypotension, hypovolemia, or anemia, and it has been shown to be a clinically useful noninvasive method for early detection of acute cardiovascular changes and persistent occult hypoperfusion in critically ill patients [ 12 ].…”

Renal resistive index in hypertensive patients

“…12 Beyond the diagnosis of renovascular HTN, RRI has been also proposed as a marker of possible benefit from revascularization. The authors conclude that this parameter is easily determinable, with high specificity and sensitivity and improves the diagnostic accuracy in the detection of renal artery stenosis.…”

“…The authors conclude that this parameter is easily determinable, with high specificity and sensitivity and improves the diagnostic accuracy in the detection of renal artery stenosis. 12 Beyond the diagnosis of renovascular HTN, RRI has been also proposed as a marker of possible benefit from revascularization. According to a prospective study in patients with a >50% unilateral or bilateral renal artery stenosis who underwent renal angioplasty or surgery, a RRI value of at least 0.8 before revascularization was a strong predictor of renal function impairment and failure of blood pressure (BP) lowering, despite the correction of renal artery stenosis.…”

Renal resistive index for renovascular hypertension: In the quest of the Holy Grail

“…Grupp and colleagues conducted a clinically important and meaningful study, evaluating an innovative hypothesis. The outcomes suggest that ΔRI k−s adds a greater diagnostic accuracy in Doppler ultrasonography for the detection of RAS.…”