Renal Artery Peak Systolic Velocity Research Articles

The effect of fetal renal artery Doppler ultrasound on neonatal outcomes in fetuses with ureteropelvic junction type obstruction

Objective: Fetal urinary tract dilatation (UTD) is one of the common fetal problems with remarkable difficulties in diagnosis and management in the antenatal and postnatal periods. This study aimed to determine the value of Doppler ultrasound assessment of the renal arteries in fetuses with ureteropelvic junction type hydronephrosis (UPJO) for the prediction of neonatal outcomes of infants. Materials and Methods: Fetal renal artery Doppler values were evaluated in pregnant women between 28-32 weeks. Measurements were taken for Doppler values and the fetal obstruction and were classified through the utilization of UTD classification. Based on postnatal ultrasound, these infants were grouped by UTD classification. Results: There was a statistically significant difference between the left renal artery Systolic/Diastolic (S/D) Ratio and bilateral renal artery Peak Systolic Velocity (PSV) values of the control and patient groups, (p<0.05). PSV values were higher in the patient group. The difference between the pulsality index, resistive index, and right renal artery S/D values of the control and patient groups was not statistically significant (p>0.05). Conclusion: Fetal renal artery Doppler is not effective in predicting the degree of hydronephrosis and renal damage in postnatal follow-up of fetuses with a diagnosis of UPJO.

Impact of Breathing Control Training Program on sonographic quantification of abdominal vasculature.

To compare vascular scanning parameters (vessel diameter, peak systolic velocity, end-diastolic velocity, and resistive index) and scanning time before and after breathing control training program for selected abdominal vessels. This study was pre and post quasi-experimental. The researchers designed a breathing training program that gives participants instructions through a video describing breathing maneuvers. Data were collected at the ultrasound laboratory/College of Health and Rehabilitation Sciences in Princess Nourah bint Abdul Rahman University, Riyadh, Saudi Arabia from January 2023 to November 2023. About 49 volunteers at the university participated in the study. Scanning was performed two times for the right renal artery, upper abdominal aorta, inferior vena cava, and superior mesenteric artery. Scanning time was measured before and after the program as well. A paired sample t-test was used to compare the parameters means and time before and after the program. The program had a significant effect on the following parameters: right renal artery peak systolic velocity (p=0.042), upper abdominal aortic peak systolic velocity, and resistive index (p=0.014, p=0.014 respectively), superior mesenteric artery and inferior vena cava diameters (p=0.010 and p=0.020). The scanning time was reduced significantly (p<0.001). The breathing training program saves time and improves ultrasound measurement quality. Hospitals and health centers should consider the importance of breathing control training programs before abdominal scanning.

The performance of duplex ultrasonography for the assessment of renal artery stenosis in Takayasu’s arteritis patients

BackgroundThis study intends to analyze the hemodynamic parameters of the renal artery in patients with Takayasu’s arteritis (TAK) to explore the diagnostic efficacy of duplex ultrasonography in assessing the involved renal artery in TAK patients.MethodsOne hundred fifteen TAK patients with 314 renal arteries were retrospectively analyzed, who were admitted to Peking Union Medical College Hospital between 2017 and 2022. These patients underwent both renal artery ultrasonography and angiography within a 4-week period. Specifically, the study compared seven ultrasonic parameters across groups categorized by the severity of renal artery stenosis (RAS), including noninvolvement, < 50% stenosis, 50–69% stenosis, and 70–99% stenosis. Receiver operating characteristic (ROC) curves were employed to determine the optimal threshold values for renal artery peak systolic velocity (RPSV), renal-aortic PSV ratio (RAR), and renal-interlobar PSV ratio (RIR) in order to diagnose various degrees of RAS in TAK patients.ResultsStatistically significant differences were observed in RAR and RIR among the four groups (all P < 0.05). However, no statistically significant differences were found in RPSV and AT between the moderate stenosis group (50–69% stenosis) and the severe stenosis group (70–99% stenosis). The discrimination of interlobar PSV (IPSV) and interlobar RI (IRI) was not significant, and IEDV did not show statistical significance among the four groups.For TAK patients, the recommended thresholds of RPSV for the diagnosis of renal artery involvement (RAI), ≥ 50% RAS, and ≥ 70% RAS were determined to be 143 cm/s, 152 cm/s, and 183 cm/s, respectively. The sensitivities, specificities, and accuracies of these thresholds were all found to be greater than 80%. Additionally, the optimal thresholds of RIR for detecting RAI, ≥ 50% RAS, and ≥ 70% RAS were determined to be 4.6, 5.6, and 6.4, respectively, with satisfactory diagnostic efficiencies. The areas under the curve (AUCs) for RPSV and RIR were calculated to be 0.908 and 0.910, respectively, for the diagnosis of ≥ 50% RAS, and 0.876 and 0.882 for the diagnosis of ≥ 70% RAS. When the aortic PSV is greater than or equal to 140 cm/s, the RAR exhibits inadequate diagnostic efficacy. Conversely, when the aortic PSV is less than 140 cm/s, a RAR value of 2.2 or higher can be employed as the diagnostic threshold for identifying RAS of 70% or greater, with a sensitivity of 84.00%, specificity of 89.93%, and an overall accuracy of 89.08%.ConclusionIn the present study, it has been demonstrated that RPSV and RIR possess substantial diagnostic value as ultrasonic parameters for diagnosing RAS in TAK patients. Furthermore, when assessing the diagnostic efficacy of RAR, it is crucial to consider the severity of aortic stenosis as a determining factor.

Compact Point of Care Ultrasound Reveals Hemodynamic Abnormalities in Children with Sickle Cell Disease

In sickle cell disease (SCD), kidney related morbidity and mortality are significant, with ~80% of patients displaying signs of chronic kidney disease (CKD) by age 401 and kidney related mortality being the third leading cause of death (16.4%)2. Children with SCD are also prone to kidney disease with 20% of 12 years-old displaying microalbuminuria4 and enuresis and hyposthenuria commonly observed in infants4. Current clinical guidelines are insufficient as they ignore pediatric disease until the development of late signs like proteinuria or large drops in eGFR have occurred5. A major limitation in the assessment of kidney disease in children with SCD is the incomplete understanding of disease progression and the lack of suitable biomarkers to discriminate health and disease. Serum creatinine based eGFR is the most common biomarker of kidney function but is poorly validated and relatively insensitive in SCD patients due low muscle mass and hyperfiltration6. Point of care ultrasound (POCUS) offers a non-invasive alternative to blood based biomarkers. POCUS has proven clinical utility in decreasing primary and secondary stroke7. Additionally, POCUS technology now offers compact, cartless systems, with tablet and smartphone compatibility, multiprobe functionality in a single probe and an economical price point (<3000$)8. Therefore, the goals of this study were two-fold. 1) Determine the feasibility of renal assessment using compact POCUS in children with SCD in a clinical setting. 2) Establish normative values for possible compact POCUS biomarkers that could supplement existing biomarkers of kidney disease in SCD. Methods: Studies were performed with informed consent under an IRB approved protocol. 18 patients with SCD were recruited during their routine clinical visit to undergo a 10-20 minute ultrasound examination. All POCUS exams were performed in supine position, on the right kidney by an experienced imaging researcher (AB, +10 years). Images were acquired with a Butterfly IQ+ (Burlington, MA, USA) system and an Apple Smartphone (Cupertino, CA, USA). The abdominal preset and B-mode imaging was used to determine the long axis renal length and echogenicity of the renal/liver parenchyma. The cardiac preset, pulsed Doppler mode was used to determine the peak systolic velocity (PSV), end diastolic velocity (EDV) and resistive index (RI = (PSV-EDV)/PSV) of the main right renal artery. Images were saved to a cloud based, HIPPA protected database, downloaded to a local workstation and processed using custom MATLAB scripts. An angle correction of 1/cos(60°) was applied to the uncorrected velocity values. Results: Renal length and serum creatinine was measured in 18 patients with SCD (3 HbSC, 15 HbSS) and pulsed Doppler estimates were obtained in 14 of 18 subjects (hemoglobin 9.9±2.3,12 male). The average renal length was 8.7±1.3 cms and serum creatinine was 0.69±0.16 and showed a statistically significant increase with respect to age (Figure 1). The average angle corrected main renal artery PSV was 74.5±64.4 cm/s and RI was 0.49±0.33 and both decreased with respect to age (Figure 1). The average echogenicity ratio between kidney and liver parenchyma was 0.64±0.14 and was uncorrelated with age. Discussion: This work demonstrates that high quality structural and hemodynamic images can be acquired with low cost, compact POCUS in a clinical setting. The age dependent increase in serum creatinine9 and kidney length10 were in good agreement with prior cart-based sonography work in healthy children. Conversely, the age dependent drop in main renal artery PSV and RI was in opposition to work in healthy children that showed no change11 or an increase with age12. The clinical significance of abnormally elevated velocity in young children with SCD and its impact on the development of sickle nephropathy should be studied in more detail. Future work comparing cross-sectional and longitudinal variability in compact POCUS and physiologic biomarkers of kidney function in both pediatric and adult subjects with and without SCD is ongoing.

Renal Artery Stenosis due to Entrapment

Common etiologies of renovascular occlusive disease include atherosclerosis disease, developmental fibrotic conditions such as fibromuscular dysplasia, and vasculitis. Extrinsic compression of the renal artery is a rarely reported phenomenon but can lead to similar clinical manifestations. We report recent experience with 2 patients who presented with extrinsic renal artery compression due to entrapment. Diagnosis was made with a constellation of findings on computed tomography angiography, dynamic duplex sonography, and catheter angiography. Both patients had hypertension and 1 had downstream subsegmental renal infarcts. The patients, both with right-sided renal artery entrapment, were treated with open surgical decompression. Exposure was achieved via extended Kocher maneuver followed by mobilization of the right kidney and, in 1 patient, detachment of the right lobe of liver to allow circumferential exposure of the proximal right renal artery to the aorta. All entrapping tissue was circumferentially released. Both operations were uncomplicated. Intraoperative sonography was used to confirm luminal patency of the released segments. Follow-up of renal artery duplex in both patients demonstrated resolution of dynamic compression. Renal artery peak systolic velocity and accelerations indices were all within normal limits. In both patients, improvement in blood pressure control was noted and discontinuation of anticoagulation was possible in the patient who had recurrent episodes of renal infarct. Extrinsic compression of renal artery by diaphragmatic crura is rare but should be considered in younger patients or otherwise any patients with no vascular risk factors when renovascular hypertension workup yields no demonstrable intrinsic disease. A high index of suspicion should be raised when an anomalously high origin of the renal artery or proximity to the diaphragmatic crura is seen on cross-sectional imaging. Work-up should include dynamic imaging to assess compression of renal arteries during expiration. Open surgical or laparoscopic decompression of the involved renal arteries can be curative.

Evaluation of Fetal Renal Artery Doppler Indices in Pregnancies Complicated with Preeclampsia

Objective: Preeclampsia, characterized by endothelial dysfunction, is associated with maternal and fetal Doppler alterations. This study aimed to evaluate fetal renal artery Doppler indices in pregnancies complicated with preeclampsia and compare them with normotensive pregnancies. Design: This cross-sectional study enrolled 46 pregnancies complicated with preeclampsia between weeks 24 and 37 of gestation as the study group and 48 normotensive pregnancies as the control group. Materials and Methods: The abdominal aorta, its bifurcation, and the renal arteries were visualized in the coronal view of the fetal abdomen using color Doppler. Renal artery Doppler indices were measured after arising from the abdominal aorta. The angle of insonation was ≤30° from the direction of blood flow, and the sample volume was 2 mm. Fetal renal artery pulsatility index, resistance index, systolic/diastolic ratio, and peak systolic velocity (PSV) were measured. All Doppler measurements were performed in the absence of fetal movements. Moreover, demographic characteristics and the perinatal outcome data of patients were recorded. Results: The values of fetal renal artery pulsatility and resistance indices were found to be significantly lower in the study group than those in the control group (p < 0.001 and p = 0.013, respectively). The fetal renal artery systolic/diastolic ratio and PSV values were also significantly lower in the study group compared with those in the control group (p = 0.007 and p < 0.001, respectively). Renal artery pulsatility and resistance indices were negatively correlated with mean arterial pressure (r = −0.381, p < 0.001 and r = −0.267, p = 0.009, respectively). The renal artery systolic/diastolic ratio was also significantly negatively correlated with the mean arterial pressure (r = −0.257, p = 0.013). Limitations: The main limitations of this study are its cross-sectional design and the small number of participants. Another limitation of the study is that preeclamptic pregnancies complicated with fetal growth restriction were not included. Conclusion: The observed decrease in fetal renal artery Doppler impedance may be caused by the unique response of the fetal renal artery to the factors involved in the etiopathogenesis of preeclampsia than other fetal peripheral vessels. These changes in fetal renal artery indices in pregnancies complicated with preeclampsia could be taken into account in the assessment of fetal health.

Influence of renal artery stenosis morphology on hemodynamics

Objective Currently, the clinical classification of the severity of renal artery stenosis (RAS) solely depends on the degree of stenosis. In addition, when the stenosis degree is between 50% and 70%, the clinical strategy is decided based on whether the RAS is hemodynamically significant. In this study, the influence of RAS morphological parameters on hemodynamics was numerically analyzed to provide a theoretical basis for clinical treatment. Methods Idealized RAS models were established to investigate the hemodynamic effects of the stenosis length, asymmetric stenosis, and direction of the opening of the renal artery. Results The longer the stenosis length, the greater is the ratio of the low time-averaged wall shear stress (WSS) and high oscillatory shear index (OSI) area distal stenosis (when the stenosis area is the same). In addition, asymmetric stenosis leads to a significant increase in the ratio of the renal artery peak systolic velocity (R-PSV) and the abdominal aorta peak systolic velocity (A-PSV) when the stenosis area is 60–70%. Furthermore, the fraction flow reserve (FFR) of the RAS model with 12 mm stenosis length, upward eccentricity and upward direction of renal artery opening was approximately equal to the cumulative value of the influence of different stenosis morphologies on FFR. Conclusion An assessment of the severity of RAS should consider the stenosis area and other morphological parameters, including the length and asymmetry of RAS as well as the direction of the opening of renal artery, particularly when the stenosis degree of RAS is between 50% and 70%.

Renal artery Doppler studies in the assessment of monochorionic, diamniotic twin pregnancies with and without twin-twin transfusion syndrome

In monochorionic, diamniotic twin pregnancies complicated by twin-twin transfusion syndrome, imbalanced fetofetal blood shunting and discordant activation of the renin-angiotensin system result in a hypovolemic, oliguric donor twin and a hypervolemic, polyuric recipient twin. Renal artery Doppler assessments have been reported to predict oligohydramnios in singleton pregnancies; however, their value in assessing monochorionic, diamniotic twin gestations, including pregnancies complicated by twin-twin transfusion syndrome, remains unstudied. This investigation evaluated whether renal artery Doppler parameters are different between sets of monochorionic, diamniotic twins with and without twin-twin transfusion syndrome. We conducted a prospective study of women with monochorionic, diamniotic twin pregnancies complicated by twin-twin transfusion syndrome and women with gestational-age matched monochorionic, diamniotic twin control pregnancies without twin-twin transfusion syndrome. For each twin, renal artery Doppler assessment was performed from a coronal view of the fetus, and pulsatility index, resistive index, and peak systolic velocity were measured. In twin pairs complicated by twin-twin transfusion syndrome, renal artery Doppler pulsatility index, resistive index, and peak systolic velocity intertwin ratios were calculated by comparing paired recipient-to-donor values. Similar ratios were calculated for control twin pairs. We compared each measurement between donors and controls and between recipients and controls. Intertwin ratios were compared between twin-twin transfusion syndrome cases and monochorionic, diamniotic controls. Our primary outcome was a comparison of renal artery Doppler pulsatility index measurement between donor fetuses in twin-twin transfusion syndrome cases and matched control twins. Secondary outcomes included comparisons of other renal artery Doppler parameters between twin-twin transfusion syndrome donor twins and controls and between twin-twin transfusion syndrome recipients and controls and comparisons of the renal artery Doppler parameter ratios between twin-twin transfusion syndrome and non-twin-twin transfusion syndrome twin pair groups. Finally, we performed a subgroup analysis involving pregnancies with twin-twin transfusion syndrome that underwent fetoscopic laser therapy and resulted in twin survivors to evaluate if laser therapy influenced renal artery Doppler findings. We recruited 12 donors and 12 controls. Renal artery Doppler pulsatility index and resistive index did not differ between donors and controls. However, donor renal artery Doppler peak systolic velocity (median, 14.24 [11.51-15.36]) was significantly lower than that of controls (median, 24.79 [22.46-27.03]; P<.0004). When recipient twins were compared with controls, there was no difference in renal artery Doppler pulsatility index, renal artery Doppler resistive index, or renal artery Doppler peak systolic velocity. Renal artery Doppler peak systolic velocity ratios were significantly higher among cases with twin-twin transfusion syndrome (median, 1.70 [1.53-2.02]) than controls (median, 1.06 [1.03-1.15]; P=.002). Applying a renal artery Doppler peak systolic velocity ratio cutoff of >1.35 for the diagnosis of twin-twin transfusion syndrome correctly classified 11 of 12 cases with twin-twin transfusion syndrome and all 12 controls without twin-twin transfusion syndrome (92% sensitivity and 100% specificity). Among donors with twin-twin transfusion syndrome with double survivors after undergoing laser therapy (n=4), prelaser renal artery Doppler peak systolic velocity ratios (mean, 1.46; standard deviation, 0.37) were significantly higher than postlaser renal artery Doppler peak systolic velocity ratios (mean, 0.87; standard deviation=0.37; P=.02). Postlaser intertwin renal artery Doppler peak systolic velocity ratios did not differ from control twin pairs (P=.125). Renal artery Doppler peak systolic velocity ratios differ between monochorionic, diamniotic twins with twin-twin transfusion syndrome and those without twin-twin transfusion syndrome. This effect seems to be driven by altered donor twin renal artery Doppler peak systolic velocity. Laser therapy may normalize renal artery Doppler peak systolic velocity ratios and donor twin renal artery Doppler values to those observed in monochorionic, diamniotic twins without twin-twin transfusion syndrome. Further study is warranted to explore whether renal artery Doppler peak systolic velocity has utility as a tool for twin-twin transfusion syndrome prediction, diagnosis, or staging, and fetal response to laser therapy.

Abstract No. 649 Endovascular management of transplant renal artery stenosis

Transplant renal artery stenosis (TRAS) occurs in up to 23% of renal transplant recipients, with consequences including refractory hypertension and graft failure. Endovascular treatment options for TRAS include percutaneous transluminal angioplasty (PTA) and stenting. In this study, we compare clinical outcomes of TRAS treated by PTA alone vs. PTA with stenting at a large tertiary referral center performing over 400 renal transplants per year. Thirty adult patients referred for treatment of TRAS between November 2011 and May 2019 were retrospectively reviewed. Indications for angiogram included elevated creatinine, refractory hypertension, graft dysfunction, or elevated renal artery peak systolic velocity. Primary outcomes were reduction in blood pressure (systolic/diastolic) and serum creatinine following intervention. Secondary outcomes included change in peak systolic velocity and intra-arterial pressure gradient. Sixteen patients underwent PTA alone; 14 underwent PTA with stenting (5 drug-eluting, 9 bare-metal). PTA with stenting resulted in statistically significant, sustained drop in systolic blood pressure immediately (11.5%, P = 0.0023), 1 month (7.45%, P = 0.006), and 3 months (12.0%, P = 0.0028) postintervention, but had no significant effect on creatinine at any time point. PTA alone had no significant effect on blood pressure but did result in significant creatinine reduction at 1 month (6.01%, P = 0.005) and 3 months (8.2%, P = 0.014). Baseline creatinine was higher in patients who received PTA alone (2.82 ± 1.33) vs. stenting (1.95 ± 0.68), although the difference was non-significant. No complications were noted in the PTA group; one access complication of common femoral artery pseudoaneurysm occurred in the PTA with stenting group and was treated with thrombin injection. Endovascular treatment of TRAS is safe and effective, with significant, sustained improvement in systolic blood pressure in patients treated with stent placement as compared to PTA alone.

Duplex ultrasound for identifying renal artery stenosis: direct criteria re-evaluated.

Background Renal artery duplex ultrasound (RADUS) is an established method for diagnosis of renal artery stenosis (RAS), but there is no consensus regarding optimal RADUS criteria. Purpose To define optimal cutoff values for RADUS parameters when screening for RAS using intra-arterial trans-stenotic pressure gradient measurement (PGM) as reference. Material and Methods The renal arteries of 58 consecutive patients evaluated for renovascular hypertension were examined by RADUS and PGM. Conclusive measurements with both methods were obtained in 76 arteries. Hemodynamically significant RAS was defined as PGM ≥15 mmHg and was found in 43 of the 76 arteries. RADUS parameters included renal artery peak systolic velocity (PSV) and the renal-aortic ratio (RAR) of flow velocities. Receiver operating characteristic curves (ROCs) and Youden's index were used to calculate optimal RADUS criteria for RAS. Results When traditional RADUS criteria for RAS were used, with a combination of PSV ≥180 cm/s and RAR ≥3.5, the sensitivity was 62% and the specificity was 91%. When RADUS criteria were optimized for sensitivity, then RAR ≥2.6 alone resulted in a sensitivity of 89% and a specificity of 69%. Conclusion The RAR ≥2.6 is a more sensitive criterion than traditional RADUS criteria when screening patients with clinical suspicion of RAS.

Ultrasonographic Tissue Characterization of Kidneys in Patients with Unilateral Renal Artery Stenosis

Introduction Ultrasound tissue characterization (USTC) has been applied to B-mode images of normal, young and transplanted kidneys, carotid, and peripheral atherosclerosis and venous thrombosis. We analyzed USTC from both kidneys of patients with severe unilateral renal artery stenosis. Seven women and 11 men, 79 ± 9 standard deviation (range = 57–96) years of age, were included. Severe, unilateral, renal artery stenosis was based on renal artery peak-systolic velocity (PSV) &gt; 200 cm/sec and/or renal-aortic PSV ratio &gt; 3.5. This sample population, selected sequentially by date of ultrasonographic examinations requested, was heterogeneous: kidney lengths and resistivity indices varied from 6.7 to 13.4 cm and 0.45 to 0.85. Methods USTC was applied to images selected for kidney length measurements. Pixel brightness in the 0–255 range was rescaled to zero for black and 200 for fascia brightness. Gray-scale medians (GSM) of entire kidneys were estimated for statistical comparisons between: (a) kidneys ipsilateral to stenosis (KIS), (b) kidneys contralateral to stenosis (KCS), and (c) normal, young kidneys (KN), previously published GSM = 37 ± 6 (27–48). Results Two distinct KCS subgroups were identified: (1) near-normal GSM &lt; 54 (KCSN, n = 10, 56%); and (2) elevated GSM &gt; 60 (KCSH, n = 8, 44%). Subgroup increasing GSM order was (1) KN, (2) KCSN (47 ± 7, &gt; KN, p &lt; 0.002), (3) KIS-CN (59 ± 20, &gt;KCSN, p &lt; 0.003), (4) KIS-CH (73 ± 20, &gt; KCSN, p &lt; 0.007), and (5) KCSH (78 ± 17, &gt;KIS-CN, p &lt; 0.05). GSM was independent of kidney length or resistivity index, with Pearson correlation coefficients &lt; 0.5 for either KIS or KCS, respectively. Conclusions Tissue echogenicity, represented by GSM, was an independent variable characterizing effects of unilateral renal artery stenosis on the ipsilateral or on both kidneys.

Renal duplex ultrasound findings in fenestrated endovascular aortic repair for juxtarenal aortic aneurysms

This study characterized duplex ultrasound (DUS) findings and clinical outcomes associated with covered stent placement in renal arteries during fenestrated endovascular aortic repair (FEVAR) to determine if velocity criteria for native renal artery stenosis can be applied. Data from a prospectively maintained database of patients who underwent FEVAR between January 2010 and August 2014 were obtained before FEVAR (preoperative or baseline) and at follow-up assessments at 30days, 6months, and 1, 2, and 3years. The established DUS threshold criteria for ≥60% stenosis in native renal arteries were applied at baseline and all follow-up intervals: renal artery peak systolic velocity (PSV) ≥200cm/s or renal-aortic velocity ratio (RAR) ≥3.5. Forty-nine patients underwent placement of 88 covered renal artery stents during FEVAR. At least 30-day follow-up was available for 43 patients with 80 stents. A ≥60% stenosis was identified in seven renal arteries of six patients on baseline DUS, and these patients were analyzed separately. The remaining 73 renal arteries were classified as normal or<60% stenosis at baseline, with a median PSV of 121cm/s (interquartile range, 96-143) and median RAR of 1.4 (interquartile range, 1.1-1.7). No significant differences were found between the baseline and follow-up PSV measurements at any time point. The RAR differed significantly at some time points, although median values remained below the ≥60% stenosis threshold. Some increased RAR values were attributed to low aortic velocities after repair. In the 13 patients with 17 covered renal artery stents found to have PSV or RAR exceeding a DUS threshold for ≥60% native renal artery stenosis, there was no evidence of stenosis by computed tomography angiography, of renal dysfunction by estimated glomerular filtration rate, or of renal volume decrease by three-dimensional analysis. None of the seven renal arteries with ≥60% stenosis atbaseline showed evidence of restenosis at 1, 2, or 3years. Covered stent placement in nonstenotic renal arteries during FEVAR is safe and durable, with PSV and RAR remaining in the normal or<60% stenosis range in most patients. Increases in PSV or RAR that occur are not associated with clinically significant sequelae or in-stent stenosis on computed tomography angiography. DUS velocity criteria for stenosis in native renal arteries appear to overestimate the severity of stenosis in covered stents after FEVAR.

Abstract 13892: Incidence and Risk Factors of Restenosis, and Its Impact on Blood Pressure Control After Percutaneous Transluminal Renal Angioplasty in Patients With Renovascular Hypertension

Background: Percutaneous transluminal renal angioplasty (PTRA) is one of the standard treatments for renal artery stenosis (RAS). Restenosis after PTRA may influence disease prognosis, but little is known about its frequency, risk factors, or impact on blood pressure control. Methods: This study included 175 renovascular hypertensive patients (mean age= 59.6 years; 33.7% women; 30.3% fibromuscular dysplasia [FMD]) with 207 treated renal arteries and were followed more than 12 months after PTRA. Data including blood pressure (BP), antihypertensive medication, and duplex ultrasonography (DUS) was collected before and 12 months, and then yearly after PTRA. Cure of hypertension was defines as a BP below 140/90mmHg without antihypertensive medication. Diagnosis of restenosis was based on DUS, by applying a renal aortic ratio &gt;3.5 in conjunction with a renal artery peak systolic velocity &gt; 250cm/s. Results: At 12 months after PTRA, the cumulative incidence of restenosis was 35 (20.0%). We divided the total patients into four groups on the basis of cause of RAS; FMD or atherosclerotic RAS (ARAS), and the absence/presence of restenosis, and found that the decrease in systolic BP (F=3.10, p&lt;0.05) as well as cure of hypertension (F=6.96, p&lt;0.01) were significantly different among the subgroups. Decrease in systolic BP (-31±19 vs -12±25mmHg, p&lt;0.05) as well as cure of hypertension (36.4 vs 5.0%, p&lt;0.01) were significantly greater in FMD patients without restenosis than those with restenosis; whereas no significant difference was found in patients with ARAS. During a median follow-up of 4.0 (IQR, 1.2-8.0) years, 56 patients (32.0%) developed restenosis. In multivariate Cox regression analysis, FMD was an independent predictor of restenosis (hazard ratio [HR] 2.65, p=0.02). We then divided total patients into two groups according to the cause of RAS, and found that statin use (HR 0.50) in FMD, and the presence of previous cardiovascular disease (HR 2.88) as well as severe RAS (≥90%) (HR 3.30) in ARAS were significant predictors of restenosis (p&lt;0.05, respectively). Conclusions: Incidence of restenosis after PTRA was higher in FMD than in ARAS among renovascular hypertensive patients. Assessment of restenosis is important for treatment success, especially for FMD.

Abstract P165: Incident and Associated Factors of Restenosis After Percutaneous Transluminal Renal Angioplasty in Renovascular Hypertensive Patients

Background: Percutaneous transluminal renal angioplasty (PTRA) is one of the standard treatments for renal artery stenosis (RAS). Restenosis after PTRA may influence disease prognosis, but little is unknown about the frequency or its associated factors. Methods: This study included 174 renovascular hypertensive patients (mean age= 59.5 years; 33.9% women) who underwent PTRA and were followed more than 12 months after PTRA. Data collection including blood pressure (BP), intensity of antihypertensive medication, and duplex ultrasonography (DUS) was performed before and 3, 6, and 12 months after PTRA. Cure of hypertension was defines as a BP below 140/90mmHg without antihypertensive medication. Diagnosis of restenosis was based on DUS, by applying a renal aortic ratio &gt;3.5 in conjunction with a renal artery peak systolic velocity &gt; 250cm/s. Results: At 12 months after PTRA, BP (156±25/82±15 to 133±16/75±13mmHg) as well as antihypertensive medications (2.5±1.2 to 2.1±1.3 types) decreased significantly (p&lt;0.01, respectively), and the incident of restenosis was 34 (19.5%). Compared with patients without restenosis, baseline clinical characteristics in those with restenosis showed significantly younger (46.1±23.6 vs 62.8±16.3 years), higher prevalence of female (50.0 vs 30.0%), fibromuscular dysplasia (FMD) diagnosed by angiography (58.8 vs 23.6%), and balloon PTRA without stenting (44.1 vs 18.6%), and lower numbers of antiplatelet and/or anticoagulant agents administrated after PTRA (1.3±0.6 vs 1.7±0.6 types of drug) (p&lt;0.05, respectively). Compared with atherosclerotic RAS patients (n=121), the rates of cured (25.9 vs 9.0%) and the cumulative incident rates of restenosis at 3 (20.8 vs 0 %), 6 (35.9 vs 6.6%), and 12 (37.7 vs 11.6%) months after PTRA were significantly higher in FMD (p&lt;0.01, respectively). FMD without restenosis showed a significantly greater decrease in systolic BP than that with (159±21 to 131±17 vs 154±28 to 141±25 mmHg, p&lt;0.05), whereas no significant difference was found in atherosclerotic RAS. Conclusions: Incident of restenosis after PTRA was higher in FMD than in atherosclerotic, and its incident pattern seemed to be different by causes. Especially for FMD, assessment of restenosis is important for treatment success.

Color Doppler Imaging Analysis of Retrobulbar Blood Flow Velocities in Diabetic Patients Without or With Retinopathy: A Meta-analysis.

To analyze hemodynamic changes in retrobulbar blood vessels using color Doppler imaging in diabetic patients without or with retinopathy. Pertinent publications were retrieved from 3 databases. Changes in peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) of the ophthalmic artery, central retinal artery, and short posterior ciliary artery of diabetic eyes without or with retinopathy and healthy controls were evaluated by color Doppler imaging. Comparisons were conducted in 3 groups: group 1, no retinopathy versus control; group 2, retinopathy versus control; and group 3, no retinopathy versus retinopathy. In group 1, eyes without retinopathy had a significant increase in ophthalmic artery PSV (P = .002), with no heterogeneity (Pheterogeneity = 0.09; inconsistency index [I(2)] = 46%); however, significant reductions in central renal artery PSV and EDV were shown (P = .002; P = .007, respectively), with significant heterogeneity (Pheterogeneity < .00001; I(2) = 85%; Pheterogeneity = .008, I(2) = 68%). A significant increase in ophthalmic artery RI (P = .02) was found in eyes without retinopathy, with heterogeneity (Pheterogeneity = .0009; I(2) = 74%). In group 2, central retinal artery PSV and EDV in eyes with retinopathy decreased significantly (P < 0.00001). Similar results were found for ophthalmic and short posterior ciliary artery EDVs (P= .0003; P< .00001). Ophthalmic artery RI was significantly higher in eyes with retinopathy than controls (P = .0008), with heterogeneity (Pheterogeneity < .00001; I(2) = 84%). In group 3, ophthalmic artery PSV was lower in eyes with retinopathy (P= .04) than eyes without, and central retinal artery PSV and EDV decreased significantly (P = .004; P < .00001) in eyes with retinopathy compared to eyes without. Differences in ophthalmic and central retinal artery RIs were also found in eyes with retinopathy (P = .05; P < .00001). Significant changes in retrobulbar blood flow were found in eyes without and with diabetic retinopathy, especially those with retinopathy.

Renal artery stenosis and abdominal aorta aneurysm in patients with pseudoexfoliation syndrome

To evaluate the renal arteries and abdominal aorta in patients with pseudoexfoliation syndrome (PEX). Prospective, case-control study. The study involved 49 patients with PEX and 42 control subjects. Abdominal aorta and renal arteries were examined by Doppler ultrasonography. In both renal arteries (proximal and distal portions) and abdominal aorta, the peak systolic velocity (PSV) was measured. Renal artery stenosis (RAS) was defined as the renal artery PSV >150 cm/s or renal-to-aortic ratio (RAR) >3.0. Patients who had an abdominal aortic diameter >3 cm were recorded. Computed tomographic angiography was performed to confirm these findings in patients with RAS and/or abdominal aorta aneurysm. The mean PSV in the proximal renal artery was 88.3 cm/s in PEX group and 79.5 cm/s in control group (P=0.314); in distal renal artery was 91.7 cm/s in PEX group and 93.0 cm/s in control group (P=0.794); in abdominal aorta was 76.0 cm/s in PEX group and 65.2 cm/s in control group (P=0.046). RAS was observed in nine patients with PEX and in only one patient without PEX (P=0.017). Seven out of 10 patients with RAS (six patients in PEX group; one patient in control group) had hypertension. Abdominal aorta aneurysm was observed in four patients in PEX group but not in control group (P=0.061). Our study has demonstrated that there is a significant association between PEX and RAS. The abdominal aorta aneurysm may be seen in patients with PEX.

Early duplex predicts restenosis after renal artery angioplasty and stenting

To examine the relationship between early renal duplex sonography (RDS) and restenosis after primary renal artery percutaneous angioplasty and stenting (RA-PTAS). Consecutive patients undergoing RA-PTAS for hemodynamically significant atherosclerotic renal artery stenosis with hypertension and/or ischemic nephropathy between September 2003 and July 2010 were identified from a prospective registry. Patients had renal RDS pre-RA-PTAS, within 1 week of RA-PTAS and follow-up RDS examinations after the first postoperative week for surveillance of restenosis. Restenosis was defined as a renal artery peak systolic velocity (PSV) ≥ 180 cm/s on follow-up RDS. Associations between RDS and restenosis were examined using proportional hazards regression. Eighty-three patients (59% female; 12% nonwhite; mean age, 70 ± 10 years; mean pre-RA-PTAS PSV, 276 ± 107 cm/s) undergoing 91 RA-PTAS procedures comprised the sample for this study. All procedures included a completion arteriogram demonstrating no significant residual stenosis. Mean follow-up time was 14.9 ± 10.8 months. Thirty-four renal arteries (RAs) demonstrated restenosis on follow-up with a median time to restenosis of 8.7 months. There was no significant difference in the mean PSV pre-RA-PTAS in those with and without restenosis (287 ± 96 cm/s vs 269 ± 113 cm/s; P = .455), and PSV pre-RA-PTAS was not predictive of restenosis. Within 1 week of RA-PTAS, mean renal artery PSV differed significantly for renal arteries with and without restenosis (112 ± 27 cm/s vs 91 ± 34 cm/s; P = .003). Proportional hazards regression analysis demonstrated increased PSV on first post-RA-PTAS RDS was significantly and independently associated with subsequent restenosis during follow-up (hazard ratio for 30 cm/s increase, 1.81; 95% confidence interval, 1.32-2.49; P = .0003). There was no difference in pre- minus postprocedural PSV in those with and without restenosis on follow-up (175 ± 104 cm/s vs 179 ± 124 cm/s; P = .88), nor was this associated with time to restenosis. Best subsets model selection identified first postprocedural RDS as the only factor predictive of follow-up restenosis. A receiver-operating characteristic curve was examined to assess the first week PSV post-RA-PTAS most predictive of restenosis during follow-up. The ideal cut point for RA-PSV was 87 cm/s or greater. This value was associated with a sensitivity of 82.4%, specificity of 52.6%, and area under the receiver-operating characteristic curve of 69.3%. Increased first postprocedural RA-PSV was predictive of lower estimated glomerular filtration rate in the first 2 years after the procedure (-1.6 ± 0.7 mL/min/1.73 m(2) lower estimated glomerular filtration rate per 10 cm/s increase in RA-PSV; P = .010). Early renal artery PSV within 1 week after RA-PTAS predicted renal artery restenosis and lower postprocedure renal function. Recurrent stenosis demonstrated no association with absolute elevation in PSV prior to RA-PTAS nor with the change in PSV after RA-PTAS. These data suggest that detectable differences exist in renal artery flow parameters following RA-PTAS that are predictive of restenosis during follow-up but are not apparent on completion arteriography or detectable by intra-arterial pressure measurements. Further study is warranted.

Doppler Parameters of Hepatic and Renal Hemodynamics in Patients with Liver Cirrhosis

Introduction. There are limited studies on simultaneous evaluation of liver and renal blood flow using Doppler methods. We evaluated and compared the changes of liver and renal Doppler US parameters in patients with liver cirrhosis according to the degree of liver disease. Material and Methods. We assessed a large spectrum of liver and renal Doppler US parameters in 67 patients with liver cirrhosis. Results. Significant differences between Child's classes or score, as well as MELD score, were observed in all investigated intrarenal blood flow Doppler US parameters, except renal artery peak systolic velocity, but only in some of the hepatic ones. The deviations of renal Doppler US parameters were also related with the complications of liver cirrhosis, as well as serum urea and creatinine levels. There was relationship between Doppler US parameters of hepatic artery and the corresponding renal artery Doppler US parameters. The changes of Doppler US parameters were age independent. Conclusion. Our results show, renal Doppler US parameters correlate with the severity and complications of liver cirrhosis. Because of dynamic deviations of renal Doppler US parameters with advance of liver cirrhosis, we recommend Doppler US of renal artery as a part of follow up of these patients.

Natural history and progression of atherosclerotic renal vascular stenosis

Date written: December 2008Final submission: October 2009

Associations Between Renal Duplex Parameters and Adverse Cardiovascular Events in the Elderly: A Prospective Cohort Study

Atherosclerotic renovascular disease is associated with an increased risk of cardiovascular disease (CVD) events. This study examines associations between Doppler-derived parameters from the renal artery and renal parenchyma and all-cause mortality and fatal and nonfatal CVD events in a cohort of elderly Americans. Cohort study. A subset of participants from the Cardiovascular Health Study (CHS). Through an ancillary study, 870 (70% recruitment) Forsyth County, NC, CHS participants consented to undergo renal duplex sonography to define the prevalence of renovascular disease in the elderly, resulting in 726 (36% men; mean age, 77 years) technically adequate complete studies included in this investigation. Renal duplex sonography-derived Doppler signals from the main renal arteries and renal parenchyma. Spectral analysis from Doppler-shifted frequencies and angle of insonation were used to estimate renal artery peak systolic and end diastolic velocity (both in meters per second). Color Doppler was used to identify the corticomedullary junction. Using a 3-mm Doppler sample, the parenchymal peak systolic and end diastolic frequency shift (both in kilohertz) were obtained. Resistive index was calculated as (1 - [end diastolic frequency shift/peak systolic frequency shift]) using Doppler samples from the hilar arteries of the left or right kidney with the higher main renal artery peak systolic velocity. Proportional hazard regression analysis was used to determine associations between renal duplex sonography-derived Doppler signals and CVD events and all-cause mortality adjusted for accepted cardiovascular risk factors. Index CVD outcomes were defined as coronary events (angina, myocardial infarction, and coronary artery bypass grafting/percutaneous coronary intervention), cerebrovascular events (stroke or transient ischemic attack), and any CVD event (angina, congestive heart failure, myocardial infarction, stroke, transient ischemic attack, and coronary artery bypass grafting [CABG]/percutaneous transluminal coronary intervention [PTCI]). During follow-up, 221 deaths (31%), 229 CVD events (32%), 122 coronary events (17%), and 92 cerebrovascular events (13%) were observed. Renal duplex sonography-derived Doppler signals from the renal parenchyma were associated independently with all-cause mortality and CVD outcomes. In particular, increased parenchymal end diastolic frequency shift was associated significantly with any CVD event (HR, 0.73; 95% CI, 0.62-0.87; P < 0.001). Marginally significant associations were observed between increases in parenchymal end diastolic frequency shift and decreased risk of death (HR, 0.86; 95% CI, 0.73-1.00; P = 0.06) and decreased risk of cerebrovascular events (HR, 0.78; 95% CI, 0.61-1.01; P = 0.06). Parenchymal end diastolic frequency shift was not significantly predictive of coronary events (HR, 0.84; 95% CI, 0.67-1.06; P = 0.1). CHS participants showed a "healthy cohort" effect that may underestimate the rate of CVD events in the general population. Renal duplex sonographic Doppler signals from the renal parenchyma showed significant associations with subsequent CVD events after controlling for other significant risk factors. In particular, a standard deviation increase in parenchymal end diastolic frequency shift was associated with 27% risk reduction in any CVD event.