Screening For Renal Artery Stenosis Research Articles

Abstract MP72: Renal Artery Stenosis Screening Among Women With Hypertensive Disorders Of Pregnancy And Associations With Pregnancy Outcomes

Introduction: Patients with hypertensive disorders of pregnancy (HDoP) have increased prevalence of renal artery stenosis due to fibromuscular dysplasia (FMD) that is usually diagnosed years post-partum. Because renal artery FMD is a treatable cause of hypertension, earlier diagnosis has potential to decrease maternal risk and improve pregnancy outcomes. We sought to characterize utilization of renal artery duplex screening among women with HDoP and associations with pregnancy outcomes. Hypothesis: We hypothesize that renal artery duplex screening for renal artery stenosis among women with HDoP will be low. Methods: Women diagnosed with HDoP treated at a single academic medical center from 2016-2021 were identified using ICD-9&10 codes for hypertension of pregnancy, pre-eclampsia, eclampsia, and HELLP syndrome. Screening for renal artery FMD was categorized based on performance of at least one renal duplex ultrasounds during the study period. Associations with maternal demographic factors and pregnancy outcomes based on screening status were explored using descriptive statistics and categorical tests. Results: 11,564 women diagnosed with HDoP were identified. Mean age was 37.1±8.5 years. Race was categorized as 17% African American, 5% Asian, and 73% white; 4% of women had Hispanic or Latino ethnicity. 33% of patients were current or former smokers. Renal artery stenosis screening was performed on 72 women (0.6%). No significant differences in age, race, or ethnicity were identified between screened versus unscreened patients. Renal artery duplex results were abnormal in 14/72 (19%) of women screened, and an additional 3 women were diagnosed with FMD at a non-renal anatomic location based on imaging studies other than renal artery duplex. Women screened for renal artery stenosis for 44/8386 pregnancies (0.5%) associated with HDoP during the study period and had higher rates of preterm delivery (53% versus 20%; P<0.001). Conclusions: Renal artery stenosis screening is uncommon among women with HDoP, but identified abnormal findings in a significant proportion of studies. Associations between screening and preterm delivery may reflect selection bias based on severity of HDoP symptoms and related risks. Renal artery stenosis screening may be under-utilized among women with HDoP, and expanded screening has potential to reduce both short- and long-term maternal risk and improve pregnancy outcomes.

Renovascular Disease and Mesenteric Vascular Disease.

Renal artery stenosis is caused by atherosclerosis and fibromuscular dysplasia and is associated with ischemic nephropathy, renovascular hypertension, and accelerated cardiovascular disease. Routine screening for renal artery stenosis is not recommended but is reasonable in patients who have rapid onset of hypertension, resistant hypertension, progressive renal insufficiency, recurrent pulmonary edema, or repeat admissions for heart failure. Acute mesenteric ischemia is caused by arterial embolism or thrombosis, mesenteric venous thrombosis, or nonocclusive mesenteric ischemia, whereas chronic mesenteric ischemia is most often caused by arterial obstruction. This article reviews the epidemiology, pathophysiology, diagnosis, and management of these two conditions.

Relationship between aortic valve stenosis and the hemodynamic pattern in the renal circulation, and restoration of the flow wave profile after correction of the valvular defect.

ObjectiveThe index of maximal systolic acceleration ([AImax]: maximal systolic acceleration of the Doppler waveform divided by peak systolic velocity) shows diagnostic accuracy in screening of renal artery stenosis. This study aimed to determine whether an upstream factor of resistance, such as aortic valve stenosis (AVS), can affect Doppler parameters detected in the peripheral arteries.MethodsIn this prospective study, we measured the AImax in non-stenotic renal interlobar arteries of 62 patients with AVS. Patients were divided into three groups on the basis of severity of valvulopathy as follows: mild-to-moderate AVS (M-AVS; n = 24), intermediate AVS (I-AVS; n = 15), and severe AVS (S-AVS; n = 23) based on Nishimura’s criteria.ResultsThe AImax in the renal parenchymal arteries was significantly lower in the S-AVS group (8.9 ± 3.6 s−1) than in the M-AVS (15.3 ± 3.8 s−1) and I-AVS groups (16.7 ± 5.2 s−1). The AImax was positively correlated with the aortic valve area and inversely correlated with the tranvalvular aortic pressure gradient. After aortic valve replacement, the AImax significantly increased from 10.7 ± 4.0 s−1 at baseline to 19.3 ± 4.4 s−1.ConclusionsProximal resistance can lead to diagnostic bias of Doppler parameters that are applied in the diagnosis of peripheral vasculopathies, particularly in renal artery stenosis.

Doppler ultrasonography of the renal artery: Guidelines and predictive factors for the presence of a tight stenosis. Retrospective analysis of 450 consecutive examinations

To determine how well guideline indications for ultrasonography matched with requests and results in our university hospital; to determine whether compliance with guidelines was predictive of renal artery stenosis; to identify guidelines predictive of presence of stenosis; and to determine whether other predictive factors can be recognized. Requests and results of 450 Duplex ultrasonography examinations of the renal arteries performed from January 1st 2014 to December 31st 2015 were compared with published guidelines. At least one guideline indication was identified for 212 of the 450 examinations performed (47.1%). Among these examinations, renal artery stenosis≥70% was identified in 18 patients (8.0%). No case of stenosis was identified during examinations performed outside guideline indications. Factors predictive of stenosis were: compliance with guidelines (OR=21.86 [2.88; 165.8]). Predictive guidelines were: resistant hypertension in spite of appropriate treatment (OR=3.85, [1.44; 10.33], P=0.011), accelerated hypertension (OR=7.30, [1.40; 37.99], P=0.049), sudden unexplained pulmonary edema (OR=7.30, [1.40; 37.99], P=0.049), unexplained renal insufficiency (OR=3.58, [1.37; 9.37], P=0.011), unexplained renal hypotrophy (OR=16.69, [4.38; 63.69], P<0.001), renal asymmetry (OR=4.32, [1.45; 12.85], P<0.016). No other factor was predictive of renal stenosis. These examinations had therapeutic consequences in only 50% of patients. This study confirms the relevance of published guidelines. The diagnostic-effectiveness of Duplex ultrasonography examinations to search for renal artery stenosis depends upon compliance with these guidelines.

Retrospective Study of Renal Artery Doppler evaluation of Hypertensive patients

Introduction: Doppler study is a good screening test for initial screening of renal artery stenosis however controversies exists regarding its use as screening study. This study aims to evaluate the Doppler study findings in patients with atypical hypertension.Methods: The study was a retrospective hospital record based study conducted in Metro Radiological and Imaging Center, Kathmandu. Reports of Doppler studies performed for atypical hypertension were reviewed for the duration of 6 years (2009 to 2014). Doppler studies were performed by two experienced radiologist with more than 5 and 20 years of experience. Patients with transplant kidney, patient with accessory renal artery and patient with known chronic kidney disease were excluded from the study. Data was entered in predesigned proforma and analysis was done with SPSS 21.0.Results: A total of 1001 Doppler studies done during the study period revealed abnormalities in 227 patients. The most common abnormality was elevation of main renal artery and lobar renal artery resistance index, alone which was seen in 187(82.4%) patients. Renal artery stenosis was noted in 30(13.2%) cases with 10 patients each having renal artery stenosis involving left and right renal arteries respectively and 10 patients had bilateral renal artery stenosis.Conclusion: Non-specific raised resistance index indicating renal impairment is the most common abnormality in atypical hypertensives. The presence of renal artery stenosis in atypical hypertensive is around 3%.

Renal Artery Stenosis: When to Revascularize in 2017

Atherosclerotic renal artery stenosis is the leading cause of secondary hypertension; it can also cause progressive renal insufficiency and cardiovascular complications such as refractory heart failure and flash pulmonary edema. Medical therapy including risk factor modification, renin-angiotensin-aldosterone system antagonists, lipid lowering agents, and antiplatelet therapy is the first line of treatment in all patients. Patients with uncontrolled renovascular hypertension despite optimal medical therapy, ischemic nephropathy, and cardiac destabilization syndromes who have severe renal artery stenosis are likely to benefit from renal artery revascularization. Screening for renal artery stenosis can be done with Doppler ultrasonography, computed tomographic angiography and magnetic resonance angiography. Invasive physiologic measurements are useful to confirm the severity of renal hypoperfusion and therefore improve the selection patients likely to respond to renal artery revascularization. Primary patency exceeds 80% at 5 years and surveillance for in-stent restenosis can be done with periodic clinical, laboratory, and imaging follow-up.

Accuracy of colour duplex sonography for the diagnosis of renal artery stenosis

To examine the diagnostic value of novel velocimetric colour duplex sonography indices in the screening of renal artery stenosis (RAS). We performed a retrospective analysis of all consecutively studied patients at our centre with suspected RAS, and a colour duplex sonography carried out at less than 4 months (mean 34 days) before renal angiography during a 6-year period (2002-2007). A significant RAS was defined as an at least 60% stenosis on angiography or a transstenotic mean arterial pressure gradient of at least 10 mmHg or both. In a total of 169 patients, 111 stenotic and 206 nonstenotic kidneys were examined. The sensitivity and specificity for acceleration of blood flow in early systole (ACCmax) were 85 and 75%, respectively, and for the acceleration index (ACCmax/peak systolic velocity, AImax) 83 and 79%, respectively. Corresponding values in patients with estimated glomerular filtration rate of less than 30 ml/min/1.73 m2 were 90 and 73% (for ACCmax) and 74 and 88% (for AImax). In addition, the transstenotic mean arterial pressure gradient showed a significant, though weak, negative correlation to ACCmax (r = -0.26, P = 0.02) and AImax (r = -0.29, P = 0.01) in stenotic kidneys. ACCmax and AImax provide similar, good diagnostic accuracy in the detection of a haemodynamically significant RAS, even in patients with markedly reduced glomerular filtration rate. Presumably, the lack of superiority of the novel index AImax could be explained by a highly homogenous methodological approach in the present single-centre study.

Screening for renal artery stenosis in patients with aorticoiliac occlusive disease

The prevalence of atherosclerotic renal artery disease has increased with improved life expectancy. Because renal artery stenosis is a potentially correctable cause of hypertension and ischemic nephropathy, early identification of this entity may lead to proper hypertension control and improved renal function and survival. The aim of this study was to determine the prevalence and patterns of subclinical renal artery stenosis in patients with aorticoiliac atherosclerosis. The abdominal angiographies of 44 patients with high-grade aorticoiliac occlusive disease (> 70% stenosis) were reviewed for evidence of renal artery stenosis. This was compared to a group of 20 patients with mild-to-moderate aorticoiliac disease (< 70% stenosis). These patients had no history of renal artery disease or renal failure. In patients with high-grade aorticoiliac occlusive disease, renal artery stenosis was found in 25 patients (56.8%); 13 with unilateral (29.5%) and 12 (27.3%) with bilateral involvement. A hemodynamically significant stenosis (> 50%) was found in 11 patients (25%), one of whom had bilateral stenosis (2.3%). High-grade renal artery stenosis (> 70%) or complete arterial occlusion was noted on seven sides (7.9%). The most common sites of stenosis were the origin and first centimeter of the renal artery. In patients with mild-to-moderate aorticoiliac disease, renal artery stenosis was found in two patients (10%). The present study revealed that subclinical renal artery disease may be present in more than half of the patients with high-grade aorticoiliac atherosclerosis highlighting the need for proper risk stratifications and screening programs. Based on our results, we suggest that examination of the renal arteries in these patients may be necessary in order to delay or prevent complications. Additionally, such information may have important therapeutic implications in planning reconstructive vascular surgeries or percutaneous angioplasties.

Prevalence and Predictors of Renal Artery Stenosis in Hypertensive Patients Undergoing Elective Coronary Procedures

This study explored the prevalence and predictors of renal artery stenosis in a cohort of 525 hypertensive patients referred for elective coronary procedures. Patients underwent coronary and renal arteriography. The study defined renal artery stenosis as > or =60% luminal obstruction (physiologic or hemodynamic significance was not tested). Patients were classified into groups of those with normal renal arteries, those with insignificant renal artery stenosis, and individuals with significant renal artery stenosis. The mean age was 52.6+/-8.5 years, and 403 (76.8%) were males. Significant renal artery stenosis was found in 3.6%. It correlated significantly with hypertension duration (P=.005), history of cerebrovascular stroke (P=.01), history of angioplasty to >1 coronary vessel (P=.003), and 3-vessel coronary disease (P=.0003). Multivariate regression analysis identified 2-vessel and 3-vessel coronary artery disease as independent predictors of renal artery stenosis, with odds ratios of 4.9 and 12.1, respectively. It was concluded that invasive screening for renal artery stenosis was probably warranted only in hypertensive patients with multivessel coronary disease referred for elective coronary procedures.

Is duplex scanning the best screening test for renal artery stenosis?

Screening for renal artery stenosis is indicated in patients with suspected renovascular hypertension or ischemic nephropathy to identify those who could benefit from renal artery interventions. The critical requirements for a clinically useful screening test include safety, low cost, and a high sensitivity or low false-negative rate. Arteriography remains the "gold standard" for the anatomic diagnosis of renal artery disease, but it is unsuitable for screening because of its high cost and invasive nature. Although renal duplex scanning technically is difficult, experienced laboratories have been able to achieve sensitivities and specificities in the range of 93% to 98% for identification of stenoses in the main renal arteries. Renal duplex scanning also provides a method for assessing the renal parenchyma and predicting the clinical outcome of renal revascularization. The principal limitation of renal duplex scanning is failure to identify accessory renal arteries. The finding of one or more widely patent main renal arteries makes ischemic nephropathy unlikely, because this condition results from "total" renal ischemia. However, renovascular hypertension can be present with normal main renal arteries when there are isolated stenoses involving accessory renal arteries, so further testing may be indicated in selected hypertensive patients with normal main renal arteries by duplex scanning. Currently, duplex scanning in a qualified vascular laboratory arguably is the best screening test for renal artery stenosis. Other methods for assessing the renal arteries, particularly spiral computed tomography and magnetic resonance angiography, are evolving rapidly and also may play a role in screening of selected patients.

Evaluation of duplex ultrasound and captopril renography for detection of renovascular hypertension

Renovascular hypertension is the most common form of curable secondary hypertension and, if untreated, may lead to end-stage kidney disease. Given that renal function and hypertension may improve after renal angioplasty, it is pertinent to identify patients with renal artery stenosis. The aim of the present study was to evaluate both duplex ultrasound and captopril renography for detection of renal artery stenosis among hypertensive patients. To avoid selection bias, all patients referred to our center for evaluation of renovascular hypertension were asked to participate in the study. Patients were examined by intra-renal duplex ultrasound (N = 121), measuring pulsatility index and acceleration of the blood flow during early systole. In 98 patients, 99mTc-DTPA captopril renography was performed in conjunction with duplex ultrasound. Renal angiography was performed in all patients regardless of the results of the noninvasive tests. The prevalence of renal artery stenosis was 19%. In the 98 patients examined by both duplex ultrasound and captopril renography, sensitivity and positive predictive values for detection of a renal artery stenosis of 50% degree or more were 84 and 76%, respectively, for duplex ultrasound, whereas captopril renography was associated with a sensitivity and positive predictive value of 68% for both (P = NS). Specificity and negative predictive values were 94 and 96%, respectively, for duplex ultrasound, whereas the corresponding values for captopril renography were 92% for both (P = NS). Specificity and negative predictive values were 94 and 96%, respectively, for duplex ultrasound, whereas the corresponding values for captopril renography were 92% for both (P = NS). Both duplex ultrasound and captopril renography are associated with high specificity and negative predictive values for detection of renal artery stenosis. Sensitivity and positive predictive values are at least as good for duplex ultrasound compared with captopril renography. Given that duplex ultrasound is easier to perform and more cost effective, we propose that it should be the method of first choice when screening for renal artery stenosis in a hypertensive population.

Screening for renal artery stenosis: which patients? Which test?

If a patient has clinical clues suggestive of renovascular hypertension such as persistently high blood pressure despite a multiple-drug regimen, it may be reasonable to screen him or her using captopril renography, duplex ultrasonography, or magnetic resonance angiography.

EFFECT OF ACUTE INTRAVENOUS ACE-INHIBITION ON THE INTRARENAL DOPPLER FLOW CHARACTERISTICS IN HYPERTENSIVE PATIENTS WITH AND WITHOUT UNILATERAL RENAL ARTERY STENOSIS

Assessment of intrarenal doppler signals is of particular importance in screening for renal artery stenosis. We studied the effect of acute ACE-inhibition (1,25 mg enalaprilate i.v.) on intrarenal resistive indices in 10 hypertensive patients with unilateral renal artery stenosis versus 10 patients with essential hypertension. Any changes limited to poststenotic vessels could possibly improve the diagnostic value of duplex sonography.After ACE-inhibition a significant fall of the intrarenal Resistive Index occurred in both patient groups. In cases of unilateral renal artery stenosis we saw a tendency to an increased side difference of the Resistive Index due to a greater fall on the poststenotic side.Therefore a clear advantage of duplex scanning after acute ACE-inhibition due to a limited effect of enalaprilate on poststenotic vessels was not found. The results suggest that the vascular resistance and not only the degree of renal artery stenosis is of significance for the characteristics of the doppler signal.

MR angiography after renal revascularization: spectrum of expected anatomic results and postintervention complications.

The use of magnetic resonance (MR) angiography in screening for renal artery stenosis has been extensively evaluated. However, the MR angiographic findings after renal artery revascularization are not as well characterized. The renal artery and parenchyma can be evaluated after revascularization with a comprehensive MR imaging protocol that includes T1- and T2-weighted spin-echo sequences, three-dimensional (3D) gadolinium-enhanced MR angiography, and 3D phase-contrast MR angiography. Because surgical techniques for revascularization vary, knowledge of the surgical procedure is necessary to ensure inclusion of the pertinent anatomy at 3D gadolinium-enhanced MR angiography and to define appropriate 3D phase-contrast MR angiography volumes. The 3D gadolinium-enhanced MR angiography volume can be manipulated to view relevant vascular anatomy at the optimal obliquity and section thickness. This protocol allows robust, noninvasive evaluation of the expected arterial anatomy after revascularization, including renal artery endarterectomy, aortorenal bypass grafts, and extraanatomic reconstructions. In cases of suspected postrevascularization complications, gadolinium-enhanced MR angiography is useful because of its lack of nephrotoxicity and radiation exposure. Immediate complications of renal revascularization include renal artery thrombosis, renal infarction, and perinephric hemorrhage. Long-term complications include aneurysms of bypass grafts and recurrent stenosis of the renal artery.

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Screening for renal artery stenosis: hypertension and more...

ENOVASCULAR disease is a clinical entity of increasing interest related to both improved diagnostic techniques and new options for revascularization. The clinical sequelae, hypertension that is often accelerated and progressive renal failure due to ischemic nephropathy, can be attenuated by revascularization. As the aging population predisposed to atherosclerosis grows, clinical complications related to renal artery stenosis are expected to increase. While cure or improvement of hypertension is an important goal of revascularization, excellent medical therapies are currently available that make truly refractory hypertension unusual. Ischemic nephropathy is emerging as a primary indication for diagnosis and treatment of renal artery disease, particularly since there are no therapeutic alternatives to revascularization and because it is an important cause of progressive renal failure

Secondary hypertension in the elderly.

This paper discusses the most significant aspects of secondary hypertension in older patients against the background of a rising proportion of elderly in the hypertensive population. Renal artery stenosis and pheochromocytoma are singled out as those causes of secondary hypertension which appear to be related to older age. The available data relevant to epidemiology of these conditions and age-dependent clinical characteristics are reviewed. Preservation of renal function in the elderly with renal artery stenosis is underlined as an important goal of therapy with revascularising techniques. It is proposed that screening for renal artery stenosis and pheochromocytoma may be equally important in the elderly as in the younger hypertensive patient.

Screening of renal artery stenosis: Assessment with magnetic resonance angiography at 1.0 T

The results of MR angiography at 1.0 T with digital intraarterial angiography in the screening of patients with suspected renal hypertension were compared. In the first phase of the study, 10 volunteers underwent examination with both two-dimensional (2D) with traveling saturation time-of-flight (TOF) magnetic resonance angiography (MRA) with various parameters to develop a protocol for evaluation of the renal arteries. In the second phase, 36 patients with suspected renovascular hypertension underwent both 2D TOF MRA and intraarterial digital angiography to evaluate the clinical value of MRA. The degree of stenosis was graded with a two-point scale. In volunteers, using 2D acquisitions, C/N ratios indicated the best flip angle as being 55° ( p = .02). MRA showed 100% ( 70 70 ) of all main arteries and 86% ( 6 7 ) of all accessory renal arteries seen on angiography. MRA had a sensitivity of 94% ( 15 16 ) and a specificity of 98% ( 60 61 ) for detection of stenoses of greater than 50% present in 14 patients. 2D-TOF MRA at 1.0 T shows promise in the noninvasive diagnosis of patients with suspected renovascular hypertension.

Preliminary assessment of captopril sonography in screening for renal artery stenosis.

We assessed the usefulness of the resistive index (RI) and renal length in predicting a significant renal artery stenosis (RAS) and evaluated the effect of captopril on the RI in kidneys with and without a significant RAS. The RIs and renal lengths of both kidneys were measured in 39 patients who were referred for captopril renography for suspected renovascular hypertension. The difference in RIs (delta RI), the smaller RI (SRI), the difference in lengths (delta L), and the shorter length (SL) of the patient's two kidneys were determined. The accuracy of each of these parameters was calculated using captopril renography (n = 39) and arteriography (n = 9) as the gold standards. There was a significant difference in the delta RI (P < .05), SRI (p < .001), and delta L (p < .05) in patients with a positive captopril renogram for a significant RAS. Captopril increased delta RI (p = .052) in patients with a positive captopril renogram (n = 6). Use of an SRI threshold of less than .55 resulted in ultrasound being as accurate as captopril renography in predicting an angiographically documented stenosis of greater than or equal to 50%. The RI and renal length are useful in detecting a significant RAS. In this preliminary study, captopril was shown to increase delta RI in patients with a significant RAS, but larger prospective studies are necessary to further assess the value of captopril sonography in detecting a significant RAS.

The value of the resistive index in screening for renal artery stenosis

The value of the resistive index in screening for renal artery stenosis