Dataset Information

Kidney volume to GFR ratio predicts functional improvement after revascularization in atheromatous renal artery stenosis.

ABSTRACT:

Background

Randomized controlled trials (RCT) have shown no overall benefit of renal revascularization in atherosclerotic renovascular disease (ARVD). However, 25% of patients demonstrate improvement in renal function. We used the ratio of magnetic resonance parenchymal volume (PV) to isotopic single kidney glomerular filtration rate (isoSKGFR) ratio as our method to prospectively identify "improvers" before revascularization.

Methods

Patients with renal artery stenosis who were due revascularization were recruited alongside non-ARVD hypertensive CKD controls. Using the controls, 95% CI were calculated for expected PV:isoSK-GFR at given renal volumes. For ARVD patients, "improvers" were defined as having both >15% and >1ml/min increase in isoSK-GFR at 4 months after revascularization. Sensitivity and specificity of PV:isoSK-GFR for predicting improvers was calculated.

Results

30 patients (mean age 68 ±8 years), underwent revascularization, of whom 10 patients had intervention for bilateral RAS. Stented kidneys which manifested >15% improvement in function had larger PV:isoSK-GFR compared to controls (19±16 vs. 6±4ml/ml/min, p = 0.002). The sensitivity and specificity of this equation in predicting a positive renal functional outcome were 64% and 88% respectively. Use of PV:isoSK-GFR increased prediction of functional improvement (area under curve 0.93). Of note, non-RAS contralateral kidneys which improved (n = 5) also demonstrated larger PV:isoSK-GFR (15.2±16.2 ml/ml/min, p = 0.006).

Conclusion

This study offers early indicators that the ratio of PV:isoSK-GFR may help identify patients with kidneys suitable for renal revascularization which could improve patient selection for a procedure associated with risks. Calculation of the PV:isoSK-GFR ratio is easy, does not require MRI contrast agent.

SUBMITTER: Chrysochou C

PROVIDER: S-EPMC5464522 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Publications

Kidney volume to GFR ratio predicts functional improvement after revascularization in atheromatous renal artery stenosis.

Chrysochou Constantina C Green Darren D Ritchie James J Buckley David L DL Kalra Philip A PA

PloS one 20170608 6

<h4>Background</h4>Randomized controlled trials (RCT) have shown no overall benefit of renal revascularization in atherosclerotic renovascular disease (ARVD). However, 25% of patients demonstrate improvement in renal function. We used the ratio of magnetic resonance parenchymal volume (PV) to isotopic single kidney glomerular filtration rate (isoSKGFR) ratio as our method to prospectively identify "improvers" before revascularization.<h4>Methods</h4>Patients with renal artery stenosis who were d ...[more]

PMID: 28594847

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Project description:BACKGROUND:Atherosclerotic renal artery stenosis reduces renal blood flow (RBF) and amplifies stenotic kidney hypoxia. Revascularization with percutaneous transluminal renal angioplasty (PTRA) and stenting often fails to recover renal function, possibly because of ischemia/reperfusion injury developing after PTRA. Elamipretide is a mitochondrial-targeted peptide that binds to cardiolipin and stabilizes mitochondrial function. We tested the hypothesis that elamipretide plus PTRA would improve renal function, oxygenation, and RBF in patients with atherosclerotic renal artery stenosis undergoing PTRA. METHODS AND RESULTS:Inpatient studies were performed in patients with severe atherosclerotic renal artery stenosis scheduled for PTRA. Patients were treated before and during PTRA with elamipretide (0.05 mg/kg per hour intravenous infusion, n=6) or placebo (n=8). Stenotic kidney cortical/medullary perfusion and RBF were measured using contrast-enhanced multidetector CT, and renal oxygenation by 3-T blood oxygen level-dependent magnetic resonance imaging before and 3 months after PTRA. Age and basal glomerular filtration rate did not differ between groups. Blood oxygen level-dependent imaging demonstrated increased fractional hypoxia 24 hours after angiography and stenting in placebo (+47%) versus elamipretide (-6%). These were reverted to baseline 3 months later. Stenotic kidney RBF rose (202±29-262±115 mL/min; P=0.04) 3 months after PTRA in the elamipretide-treated group only. Over 3 months, systolic blood pressure decreased, and estimated glomerular filtration rate increased (P=0.003) more in the elamipretide group than in the placebo group (P=0.11). CONCLUSIONS:Adjunctive elamipretide during PTRA was associated with attenuated postprocedural hypoxia, increased RBF, and improved kidney function in this pilot trial. These data support a role for targeted mitochondrial protection to minimize procedure-associated ischemic injury and to improve outcomes of revascularization for human atherosclerotic renal artery stenosis. CLINICAL TRIAL REGISTRATION:URL: https://www.clinicaltrials.gov. Unique identifier: NCT01755858.

Project description:The purpose of this study was to define the relationship between left ventricular diastolic function and survival after renal revascularization.Seventy-six adult patients (49 women, 27 men; mean age: 63 ± 13 years) with preoperative echocardiography who underwent renal revascularization for atherosclerotic disease were identified. Diastolic function was estimated from the early diastolic transmitral flow velocity (E), the atrial transmitral flow velocity (A), and the mitral annular tissue doppler velocity (e'). Patients were divided into two groups of diastolic dysfunction as either none/mild (E/A ? 0.75, E/e' <10) or moderate/severe (E/A >0.75, E/e' ? 10). Perioperative and follow-up mortality were determined from a prospective vascular database and the National Death Index. Descriptive statistics were calculated and postoperative survival was estimated by product-limit methods. Associations between preoperative factors, perioperative factors, and follow-up survival were examined using proportional hazards regression models. A forward stepwise variable selection procedure was used to select a "best" model to predict follow-up survival.Seventy-six patients were followed for an average of 41.9 months after renal revascularization. Within this group, 47 of 76 patients (61.8%) were identified as having moderate or severe diastolic dysfunction. Diastolic dysfunction had no apparent association with abnormal systolic function. The mean ejection fraction for those with moderate/severe diastolic dysfunction was 57.7% ± 11.5%. When comparing the moderate/severe and none/mild groupings of diastolic dysfunction, there was a significant difference in left ventricular mass index (151.9 ± 48.9 vs 125.3 ± 31.7; P = .0087). There were five deaths in the perioperative period and 20 deaths on follow-up. Among perioperative survivors, hypertension was cured or improved in 82% of the none/mild group and 53% of the moderate/severe group (P = .012). In multivariable analysis, none/mild diastolic dysfunction was significantly and independently associated with an improvement in blood pressure after revascularization (odds ratio [OR], 6.2; 95% confidence interval [CI], 1.4-28.6; P = .018). Ejection fraction was not associated with survival. After forward variable selection, moderate/severe diastolic dysfunction (hazard ratio [HR], 5.8; 95% CI 1.4-25; P = .018) was the only variable to demonstrate a significant and independent association with follow-up survival.Diastolic dysfunction, but not systolic dysfunction, was frequent in patients with renovascular disease. Blood pressure response and follow-up survival after renal revascularization demonstrated significant and independent associations with diastolic function. Consideration of diastolic function should be included in the management of patients with atherosclerotic renovascular disease.

Project description:As a non-invasive, side effect-free and cost-effective method, ultrasonography represents the method of choice for the diagnosis of renal artery stenosis. Four different criteria in total, including two direct criteria in peak systolic velocity (PSV) and renal aortic ratio (RAR) and two indirect criteria in resistance index (RI) and acceleration time (AT) for the measurement of relevant renal artery stenosis are described, each demonstrating highly variable accuracy in studies. Furthermore, there is controversy over the degree beyond which stenosis becomes therapeutically relevant and which ultrasound PSV is diagnostically relevant in terms of stenosis grading.This article gives a critical review based on a selective literature search on measurement methodology and the validity of ultrasound in renal artery stenosis. A critical evaluation of methods and a presentation of measurement principles to establish the most precise measurement method possible compared with the gold standard angiography, as well as an evaluation of the importance of computed tomography angiography (CTA) and magnetic resonance angiography (MRA).The PSV provides high sensitivity and specificity as a direct measurement method in stenosis detection and grading. Most studies found sensitivities and specificities of 85-90?% for >?50?% stenosis at a PSV >?180-200 cm/s in ROC curve analysis. Other methods, such as the ratio of the PSV in the aorta to the PSV in the renal artery (RAR) or indirect criteria, such as side to side differences in RI (dRI) or AT can be additionally used to improve accuracy. Contrast-enhanced ultrasound improves accuracy by means of echo contrast enhancement. Although in the past only high-grade stenosis was considered relevant for treatment, a drop in pressure of >?20 mmHg in >?50?% stenosis (PSV 180 cm/s) is classified as relevant for increased renin secretion. Stenosis in fibromuscular dysplasia can be reliably graded according to the continuity equation. Although the available studies on the grading of in-stent restenosis are the subject of controversy, there is a tendency to assume higher cut-off values for PSV and RAR. Whilst MRA and CTA demonstrate an accuracy of >?90?%, this is at the cost of possible side effects for patients, particularly in the case of pre-existing renal parenchymal damage.This article includes two additional video sequences on visualizing renal artery stenosis. This supplemental material can be found under: dx.doi.org/10.1007/s00772-015-0060-3.

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Dataset Information

Kidney volume to GFR ratio predicts functional improvement after revascularization in atheromatous renal artery stenosis.

Background

Methods

Results

Conclusion

Publications

Kidney volume to GFR ratio predicts functional improvement after revascularization in atheromatous renal artery stenosis.

Similar Datasets

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