Phase 2a Clinical Trial of Mitochondrial Protection (Elamipretide) During Stent Revascularization in Patients With Atherosclerotic Renal Artery Stenosis.

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.

Predictors and Outcomes of Postcontrast Acute Kidney Injury after Endovascular Renal Artery Intervention.

PURPOSE: To determine incidence, predictors, and clinical outcomes of postcontrast acute kidney injury (PC-AKI) following renal artery stent placement for atherosclerotic renal artery stenosis. MATERIALS AND METHODS: This retrospective study reviewed 1,052 patients who underwent renal artery stent placement for atherosclerotic renal artery stenosis; 437 patients with follow-up data were included. Mean age was 73.6 years ± 8.3. PC-AKI was defined as absolute serum creatinine increase ≥ 0.3 mg/dL or percentage increase in serum creatinine ≥ 50% within 48 hours of intervention. Logistic regression analysis was performed to identify risk factors for PC-AKI. The cumulative proportion of patients who died or went on to hemodialysis was determined using Kaplan-Meier survival analysis. RESULTS: Mean follow-up was 71.1 months ± 68.4. PC-AKI developed in 26 patients (5.9%). Patients with PC-AKI had significantly higher levels of baseline proteinuria compared with patients without PC-AKI (odds ratio = 1.38; 95% confidence interval, 1.11-1.72; P = .004). Hydration before intervention, chronic kidney disease stage, baseline glomerular filtration rate, statin medications, contrast volume, and iodine load were not associated with higher rates of PC-AKI. Dialysis-free survival and mortality rates were not significantly different between patients with and without PC-AKI (P = .50 and P = .17, respectively). CONCLUSIONS: Elevated baseline proteinuria was the only predictor for PC-AKI in patients undergoing renal artery stent placement. Patients who developed PC-AKI were not at greater risk for hemodialysis or death.

Autologous Mesenchymal Stem Cells Increase Cortical Perfusion in Renovascular Disease.

Atherosclerotic renovascular disease (RVD) reduces renal blood flow (RBF) and GFR and accelerates poststenotic kidney (STK) tissue injury. Preclinical studies indicate that mesenchymal stem cells (MSCs) can stimulate angiogenesis and modify immune function in experimental RVD. We assessed the safety and efficacy of adding intra-arterial autologous adipose-derived MSCs into STK to standardized medical treatment in human subjects without revascularization. The intervention group (n=14) received a single infusion of MSC (1.0 × 105 or 2.5 × 105 cells/kg; n=7 each) plus standardized medical treatment; the medical treatment only group (n=14) included subjects matched for age, kidney function, and stenosis severity. We measured cortical and medullary volumes, perfusion, and RBF using multidetector computed tomography. We assessed tissue oxygenation by blood oxygen level-dependent MRI and GFR by iothalamate clearance. MSC infusions were well tolerated. Three months after infusion, cortical perfusion and RBF rose in the STK (151.8-185.5 ml/min, P=0.01); contralateral kidney RBF increased (212.7-271.8 ml/min, P=0.01); and STK renal hypoxia (percentage of the whole kidney with R2*>30/s) decreased (12.1% [interquartile range, 3.3%-17.8%] to 6.8% [interquartile range, 1.8%-12.9%], P=0.04). No changes in RBF occurred in medical treatment only subjects. Single-kidney GFR remained stable after MSC but fell in the medical treatment only group (-3% versus -24%, P=0.04). This first-in-man dose-escalation study provides evidence of safety of intra-arterial infusion of autologous MSCs in patients with RVD. MSC infusion without main renal artery revascularization associated with increased renal tissue oxygenation and cortical blood flow.

Treatment of In-Stent Restenosis in Patients with Renal Artery Stenosis.

PURPOSE: To determine clinical outcomes of patients treated for renal artery in-stent restenosis (ISR) with atherosclerotic renal artery stenosis. MATERIALS AND METHODS: A retrospective review was performed of the clinical data of all patients who underwent renal artery stent placement for atherosclerotic renal artery stenosis from 1996 to 2009. Medical records of patients were reviewed for relevant clinical history, including blood pressure, antihypertensive medications, and renal function data before and after an intervention. In 1,052 patients, 1,090 renal artery stent placements were performed. Of these, 101 stents in 79 patients developed ISR, which was treated with either percutaneous transluminal angioplasty (PTA) or repeat stent placement. Procedural details, including modality of intervention, stent diameter, and time to restenosis, were recorded. Hypertensive agent and use of statins were recorded. Univariate analysis was performed to identify risk factors associated with restenosis after treatment of ISR. RESULTS: Patients treated with repeat stent placement were 6.89 times more likely to lose patency after treatment than patients treated with PTA (P < .01). No additional clinical or procedural factor, including smoking history; presence of cardiac, renal, or metabolic disease; use of statin at time of ISR treatment; or diameter of treatment (stent or PTA), had a significant association with duration of stent or angioplasty patency. CONCLUSIONS: Treatment of renal artery ISR with PTA among patients with atherosclerotic renal artery stenosis has a lower rate of subsequent ISR compared with repeat stent placement.

Atherosclerotic renal artery stenosis is associated with elevated cell cycle arrest markers related to reduced renal blood flow and postcontrast hypoxia.

BACKGROUND: Atherosclerotic renal artery stenosis (ARAS) reduces renal blood flow (RBF), ultimately leading to kidney hypoxia and inflammation. Insulin-like growth factor binding protein-7 (IGFBP-7) and tissue inhibitor of metalloproteinases-2 (TIMP-2) are biomarkers of cell cycle arrest, often increased in ischemic conditions and predictive of acute kidney injury (AKI). This study sought to examine the relationships between renal vein levels of IGFBP-7, TIMP-2, reductions in RBF and postcontrast hypoxia as measured by blood oxygen level-dependent (BOLD) magnetic resonance imaging. METHODS: Renal vein levels of IGFBP-7 and TIMP-2 were obtained in an ARAS cohort (n= 29) scheduled for renal artery stenting and essential hypertensive (EH) healthy controls (n = 32). Cortical and medullary RBFs were measured by multidetector computed tomography (CT) immediately before renal artery stenting and 3 months later. BOLD imaging was performed before and 3 months after stenting in all patients, and a subgroup (N = 12) underwent repeat BOLD imaging 24 h after CT/stenting to examine postcontrast/procedure levels of hypoxia. RESULTS: Preintervention IGFBP-7 and TIMP-2 levels were elevated in ARAS compared with EH (18.5 ± 2.0 versus 15.7 ± 1.5 and 97.4 ± 23.1 versus 62.7 ± 9.2 ng/mL, respectively; P< 0.0001); baseline IGFBP-7 correlated inversely with hypoxia developing 24 h after contrast injection (r = -0.73, P< 0.0001) and with prestent cortical blood flow (r = -0.59, P= 0.004). CONCLUSION: These data demonstrate elevated IGFBP-7 and TIMP-2 levels in ARAS as a function of the degree of reduced RBF. Elevated baseline IGFBP-7 levels were associated with protection against postimaging hypoxia, consistent with 'ischemic preconditioning'. Despite contrast injection and stenting, AKI in these high-risk ARAS subjects with elevated IGFBP-7/TIMP-2 was rare and did not affect long-term kidney function.

Impact of Chronic Kidney Disease on Clinical Outcomes of Endovascular Treatment for Femoropopliteal Arterial Disease.

PURPOSE: To evaluate effect of chronic kidney disease (CKD) on all-cause mortality, major adverse limb event (MALE), MALE and postoperative death (MALE + POD), and amputation after endovascular treatment of femoropopliteal disease. MATERIALS AND METHODS: A retrospective review from January 2002 to October 2011 was performed of 440 patients who underwent endovascular treatment of symptomatic femoropopliteal disease for claudication (n = 251) or critical limb ischemia (CLI) (n = 267). CKD stage was divided based on Kidney Dialysis Outcomes Quality Initiative classification. Outcomes and factors associated with amputation, MALE, and MALE + POD were determined. RESULTS: Patients with diabetes (hazard ratio [HR] = 2.2; 95% confidence interval [CI], 1.3-3.6; P = .002) and runoff score of 0 or 1 (HR = 2.0; 95% CI, 1.2-3.4; P = .01) relative to runoff score of 3 were at increased risk of amputation. Patients with baseline glomerular filtration rate < 45 mL/min/1.73 m(2) had a 17% increase in amputation for every 5-point decrease < 45 mL/min/1.73 m(2) (95% CI, 1.09-1.26; P < .001). Increase of 10 years in age (HR = 1.9; 95% CI, 1.5-2.3; P < .001), TransAtlantic Inter-Society Consensus class of C/D relative to A/B (HR = 1.6; 95% CI, 1.1-2.2; P = .01), and CLI (HR = 2.4; 95% CI, 0.5-0.9; P < .001) were associated with increased mortality. Female sex was associated with decreased risk of mortality (HR = 0.7; 95% CI, 0.5-0.9; P = .01). CONCLUSIONS: Worsening CKD is associated with higher amputation rates, all-cause mortality, and MALE + POD in patients undergoing endovascular treatment of femoropopliteal disease.

Percutaneous radiologic gastrostomy catheter placement without gastropexy: a co-axial balloon technique and evaluation of safety and efficacy.

PURPOSE: The purpose of this study is to evaluate the short-term safety and efficacy of a co-axial angioplasty balloon technique for percutaneous radiologic gastrostomy catheter placement (PRG). METHODS: A total of 65 percutaneous radiologic gastrostomy tube placements were performed with the co-axial angioplasty balloon technique from 10/1999 to 1/2014. This included 19 females and 46 males between the ages of 20-83. Without the use of T-fasteners for gastropexy, the gastrostomy tube was placed over a catheter-shaft angioplasty balloon as a co-axial system. The angioplasty balloon was used to sequentially approximate the stomach wall to the abdominal wall, dilate the tract, and was then used as a dilator to aid gastrostomy tube advancement into the gastric lumen. Technical success, complications, and dislodgements were evaluated by means of retrospective review of patient medical records and imaging. RESULTS: There was no procedural failure in any of the 65 placements. 30-day follow-up was available for 56 patients. 7 patients died within 30 days; none of the deaths were recorded as procedure-related. There was 1 major complication (1.5%) consisting of a colocutaneous fistula. There were 4 minor complications (6.2%). There was no occurrence of bleeding or skin infection while using this technique. CONCLUSIONS: PRG with the co-axial angioplasty-balloon technique is a safe and effective technique for gastrostomy placement.

Mortality and Renal Replacement Therapy after Renal Artery Stent Placement for Atherosclerotic Renovascular Disease.

PURPOSE: To identify risk factors for progression to renal replacement therapy (RRT) and all-cause mortality in patients who underwent renal artery (RA) stent placement for atherosclerotic renal artery stenosis (RAS). MATERIALS AND METHODS: A retrospective study from June 1996 to June 2009 identified 1,052 patients who underwent RA stent placement. Glomerular filtration rate at time of RA stent placement was estimated from serum creatinine level and divided into chronic kidney disease (CKD) stages 1-5. Univariate and multivariable Cox proportional hazards models were used to determine which factors were associated with each endpoint. RESULTS: Times to progression to all-cause mortality and RRT were similar for CKD stages 1/2/3A and served as the reference group. In multivariable analysis, high-grade proteinuria (P < .001) and higher CKD stage (5 vs 1/2/3A [P < .001], 4 vs 1/2/3A [P < .001], 3B vs 1/2/3A [P = .02]) remained independently associated with increased risk of progression to RRT. Angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACEI/ARB) use was associated with decreased risk of progression to RRT (P = .03). Higher CKD stage (5 vs 1/2/3A [P < .001], 4 vs 1/2/3A [P = .004]), carotid artery disease (P < .001), diabetes mellitus (P = .002), and high-grade proteinuria (P < .001) remained independently associated with all-cause mortality. Statin use was associated with decreased risk of all-cause mortality (P < .001). CONCLUSIONS: Patients with atherosclerotic RAS who undergo RA stent placement and have high-grade proteinuria and CKD stage 3B/4/5 have increased risk of progression to RRT. Patients with high-grade proteinuria, CKD stage 3B/4/5, carotid artery disease, or diabetes have increased risk for all-cause mortality after renal artery stent placement. Patients receiving ACEI/ARBs have a decreased risk of progression to RRT, and patients receiving statins have a decreased risk of all-cause mortality.

Changes in inflammatory biomarkers after renal revascularization in atherosclerotic renal artery stenosis.

BACKGROUND: Atherosclerotic renal artery stenosis (ARAS) activates oxidative stress and chronic inflammatory injury. Contrast imaging and endovascular stenting pose potential hazards for acute kidney injury, particularly when superimposed upon reduced kidney perfusion. METHODS: We measured sequential early and long-term changes in circulating inflammatory and injury biomarkers in 12 ARAS subjects subjected to computed tomography imaging and stent revascularization compared with essential hypertensive (EH) subjects of similar age under fixed sodium intake and medication regimens in a clinical research unit. RESULTS: NGAL, TIMP-2, IGFBP7, MCP-1 and TNF-α all were elevated before intervention. Post-stenotic kidney volume, perfusion, blood flow and glomerular filtration rate (GFR) were lower in ARAS than in EH subjects. TIMP-2 and IGFBP7 fell briefly, then rose over 18 h after contrast imaging and stent deployment. Circulating NGAL decreased and remained lower for 27 h. These biomarkers in ARAS returned to baseline after 3 months, while kidney volume, perfusion, blood flow and GFR increased, but remained lower than EH. CONCLUSIONS: These divergent patterns of inflammatory signals are consistent with cell cycle arrest (TIMP-2, IGFBP7) and relative protection from acute kidney injury after imaging and stenting. Sustained basal elevation of circulating and renal venous inflammatory biomarkers support ongoing, possibly episodic, renal stress in ARAS that limits toxicity from stent revascularization.

Differences in GFR and Tissue Oxygenation, and Interactions between Stenotic and Contralateral Kidneys in Unilateral Atherosclerotic Renovascular Disease.

BACKGROUND AND OBJECTIVES: Atherosclerotic renal artery stenosis (ARAS) can reduce renal blood flow, tissue oxygenation, and GFR. In this study, we sought to examine associations between renal hemodynamics and tissue oxygenation with single-kidney function, pressor hormones, and inflammatory biomarkers in patients with unilateral ARAS undergoing medical therapy alone or stent revascularization. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Nonrandomized inpatient studies were performed in patients with unilateral ARAS (>60% occlusion) before and 3 months after revascularization (n=10) or medical therapy (n=20) or patients with essential hypertension (n=32) under identical conditions. The primary study outcome was change in single-kidney GFR. Individual kidney hemodynamics and volume were measured using multidetector computed tomography. Tissue oxygenation (using R(2)* as a measure of deoxyhemoglobin) was determined by blood oxygen level-dependent magnetic resonance imaging at 3 T. Renal vein neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemoattractant protein-1 (MCP-1), and plasma renin activity were measured. RESULTS: Total GFR did not change over 3 months in either group, but the stenotic kidney (STK) GFR rose over time in the stent compared with the medical group (+2.2[-1.8 to 10.5] versus -5.3[-7.3 to -0.3] ml/min; P=0.03). Contralateral kidney (CLK) GFR declined in the stent group (43.6±19.7 to 36.6±19.5 ml/min; P=0.03). Fractional tissue hypoxia fell in the STK (fraction R(2)* >30/s: 22.1%±20% versus 14.9%±18.3%; P<0.01) after stenting. Renal vein biomarkers correlated with the degree of hypoxia in the STK: NGAL(r=0.3; P=0.01) and MCP-1(r=0.3; P=0.02; more so after stenting). Renal vein NGAL was inversely related to renal blood flow in the STK (r=-0.65; P<0.001). Biomarkers were highly correlated between STK and CLK, NGAL (r=0.94; P<0.001), and MCP-1 (r=0.96; P<0.001). CONCLUSIONS: These results showed changes over time in single-kidney GFR that were not evident in parameters of total GFR. Furthermore, they delineate the relationship of measurable tissue hypoxia within the STK and markers of inflammation in human ARAS. Renal vein NGAL and MCP-1 indicated persistent interactions between the ischemic kidney and both CLK and systemic levels of inflammatory cytokines.

Initial Results of Image-Guided Percutaneous Ablation as Second-Line Treatment for Symptomatic Vascular Anomalies.

PURPOSE: The purpose of this study was to determine the feasibility, safety, and early effectiveness of percutaneous image-guided ablation as second-line treatment for symptomatic soft-tissue vascular anomalies (VA). MATERIALS AND METHODS: An IRB-approved retrospective review was undertaken of all patients who underwent percutaneous image-guided ablation as second-line therapy for treatment of symptomatic soft-tissue VA during the period from 1/1/2008 to 5/20/2014. US/CT- or MRI-guided and monitored cryoablation or MRI-guided and monitored laser ablation was performed. Clinical follow-up began at one-month post-ablation. RESULTS: Eight patients with nine torso or lower extremity VA were treated with US/CT (N = 4) or MRI-guided (N = 2) cryoablation or MRI-guided laser ablation (N = 5) for moderate to severe pain (N = 7) or diffuse bleeding secondary to hemangioma-thrombocytopenia syndrome (N = 1). The median maximal diameter was 9.0 cm (6.5-11.1 cm) and 2.5 cm (2.3-5.3 cm) for VA undergoing cryoablation and laser ablation, respectively. Seven VA were ablated in one session, one VA initially treated with MRI-guided cryoablation for severe pain was re-treated with MRI-guided laser ablation due to persistent moderate pain, and one VA was treated in a planned two-stage session due to large VA size. At an average follow-up of 19.8 months (range 2-62 months), 7 of 7 patients with painful VA reported symptomatic pain relief. There was no recurrence of bleeding at five-year post-ablation in the patient with hemangioma-thrombocytopenia syndrome. There were two minor complications and no major complications. CONCLUSION: Image-guided percutaneous ablation is a feasible, safe, and effective second-line treatment option for symptomatic VA.

Pretreatment imaging of peripheral vascular malformations.

Peripheral vascular malformations (VMs) are complex and diverse vascular lesions which require individualized pretreatment planning. Pretreatment imaging using various modalities, especially magnetic resonance imaging and time-resolved magnetic resonance angiography, is a valuable tool for classifying peripheral VMs to allow proper diagnosis, demonstrate complete extent, identify the nidus, and distinguish between low-flow and high-flow dynamics that determines the treatment approach. We discuss pretreatment imaging findings in four patients with peripheral VMs and how diagnostic imaging helped guide management.

Stent revascularization restores cortical blood flow and reverses tissue hypoxia in atherosclerotic renal artery stenosis but fails to reverse inflammatory pathways or glomerular filtration rate.

BACKGROUND: Atherosclerotic renal artery stenosis (ARAS) is known to reduce renal blood flow, glomerular filtration rate (GFR) and amplify kidney hypoxia, but the relationships between these factors and tubulointerstitial injury in the poststenotic kidney are poorly understood. The purpose of this study was to examine the effect of renal revascularization in ARAS on renal tissue hypoxia and renal injury. METHODS AND RESULTS: Inpatient studies were performed in patients with ARAS (n=17; >60% occlusion) before and 3 months after stent revascularization, or in patients with essential hypertension (n=32), during fixed Na(+) intake and angiotensin converting enzyme/angiotensin receptors blockers Rx. Single kidney cortical, medullary perfusion, and renal blood flow were measured using multidetector computed tomography, and GFR by iothalamate clearance. Tissue deoxyhemoglobin levels (R(2)*) were measured by blood oxygen level-dependent MRI at 3T, as was fractional kidney hypoxia (percentage of axial area with R(2)*>30/s). In addition, we measured renal vein levels of neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and tumor necrosis factor-α. Pre-stent single kidney renal blood flow, perfusion, and GFR were reduced in the poststenotic kidney. Renal vein neutrophil gelatinase-associated lipocalin, tumor necrosis factor-α, monocyte chemoattractant protein-1, and fractional hypoxia were higher in untreated ARAS than in essential hypertension. After stent revascularization, fractional hypoxia fell (P<0.002) with increased cortical perfusion and blood flow, whereas GFR and neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and tumor necrosis factor-α remained unchanged. CONCLUSIONS: These data demonstrate that despite reversal of renal hypoxia and partial restoration of renal blood flow after revascularization, inflammatory cytokines and injury biomarkers remained elevated and GFR failed to recover in ARAS. Restoration of vessel patency alone failed to reverse tubulointerstitial damage and partly explains the limited clinical benefit of renal stenting. These results identify potential therapeutic targets for recovery of kidney function in renovascular disease.

TGF expression and macrophage accumulation in atherosclerotic renal artery stenosis.

BACKGROUND AND OBJECTIVES: Atherosclerotic renal artery stenosis (ARAS) reduces renal blood flow and is a potential cause of chronic kidney injury, yet little is known regarding inflammatory pathways in this disorder in human participants. This study aimed to examine the hypothesis that reduced renal blood flow (RBF) in ARAS would be associated with tissue TGF-ß activation and inflammatory cell accumulation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This cross-sectional study of ARAS of varying severity compared transjugular biopsy specimens in patients with ARAS (n=12, recruited between 2008 and 2012) with tissue from healthy kidney donors (n=15) and nephrectomy specimens from individuals with total vascular occlusion (n=65). ARAS patients were studied under controlled conditions to measure RBF by multidetector computed tomography and tissue oxygenation by blood oxygen level-dependent magnetic resonance imaging. RESULTS: Compared with the nonstenotic contralateral kidneys, RBF was reduced in poststenotic kidneys (242±149 versus 365+174 ml/min; P<0.01) as was single-kidney GFR (28±17 versus 41±19 ml/min; P<0.01), whereas cortical and medullary oxygenation were relatively preserved. Tissue TGF-ß immunoreactivity was higher in ARAS patients compared with those with both normal kidneys and those with total occlusion (mean score 2.4±0.7 versus 1.5+1.1 in the nephrectomy group and versus 0±0 in donors; P<0.01). By contrast, the number of CD68+ macrophages was higher with greater disease severity (from 2.2±2.7 in normal to 22.4±18 cells/high-power field in nephrectomy samples; P<0.001). CONCLUSIONS: The results of this study indicate robust stimulation of TGF-ß associated with macrophage infiltration within the human kidney with vascular occlusive disease.

High temporal and spatial resolution imaging of peripheral vascular malformations.

PURPOSE: To assess the performance of a recently developed 3D time-resolved CE-MRA technique, Cartesian Acquisition with Projection-Reconstruction-like sampling (CAPR), for accurate characterization and treatment planning of vascular malformations of the periphery. MATERIALS AND METHODS: Twelve patient studies were performed (eight female, four male; average age, 33 years). The protocol consisted of three-dimensional (3D) time-resolved CE-MRA followed by a single late phase T1-weighted acquisition. Vascular malformations were imaged in the forearm, hand, thigh, and foot. Imaging evaluation was performed for accurate characterization of lesion type, identification of feeding and draining vessels, involvement with surrounding tissue, overall quality for diagnosis and treatment planning, and correlation with conventional angiography. RESULTS: Time-resolved CE-MRA allowed for characterization of malformation flow and type. Feeding and draining vessels were identified in all cases. Overall quality for diagnosis and treatment planning was 3.58/4.0, and correlation with conventional angiography was scored as 3.89/4.0. CONCLUSION: The CAPR time series has been shown to portray the temporal dynamics and structure of vascular malformations as well as the normal vasculature with high quality. CAPR time-resolved imaging is able to accurately characterize high and low flow lesions, allowing for pretreatment lesion assessment and treatment planning. Delayed imaging is important to capture complete filling of very slow flow vascular malformations.

Clinical outcomes in patients with renal artery stenosis treated with stent placement with embolic protection compared with those treated with stent alone.

PURPOSE: To compare the clinical outcomes in patients with chronic renal insufficiency (CRI) and renal artery stenosis (RAS) following renal artery (RA) stent placement with and without embolic protection device (EPD) usage. MATERIALS AND METHODS: Eighteen patients who had RA stent placement with EPD were matched to control patients (RA stent only). Blood pressure, number of hypertensive medications, and estimated glomerular filtration rate (eGFR) at 3 months before the procedure and after 12 months were determined. An increase of ≥ 20% in eGFR at 12 months from baseline was defined as "improvement," decrease of ≥ 20% as "deterioration," and an eGFR change between those values as "stabilization" at 12 months. RESULTS: At 12 months, stage 4 patients treated with EPD had significantly higher eGFR than controls (P = .01). There was no statistical difference in blood pressure outcomes between the 2 groups. CONCLUSIONS: Patients with stage 4 CRI did significantly better with EPD than those treated without it.

Percutaneous ultrasound-guided thrombin injection of a post-traumatic pancreatic pseudoaneurysm in a pediatric patient.

Non-operative management for blunt injuries to the proximal pancreas has become increasingly common. A bleeding pseudoaneurysm in the setting of a traumatic pancreatic pseudocyst presents a morbid operation. We present the case of a 15-year old with a grade V pancreatic injury that developed a bleeding pseudoaneurysm successfully treated with percutaneous ultrasound-guided thrombin injection.

Association of filtered sodium load with medullary volumes and medullary hypoxia in hypertensive African Americans as compared with whites.

BACKGROUND: African Americans develop hypertension earlier with more target manifestations than whites despite having a higher glomerular filtration rate (GFR) for any level of serum creatinine. STUDY DESIGN & PARTICIPANTS: This study tested the hypothesis that increased GFR and sodium reabsorption in African Americans is associated with increased metabolic work and medullary hypoxia in 49 nondiabetic patients with essential hypertension (29 whites and 20 African Americans) following a constant-sodium diet (150 mEq/d) and renin-angiotensin system blockade. PREDICTORS: Ethnicity, age, measured GFR, sodium excretion, and body mass index. OUTCOMES: We examined cortical and medullary volumes and blood flows using multidetector computed tomography and intrarenal deoxyhemoglobin (R2*) using blood oxygen level-dependent magnetic resonance. RESULTS: Blood pressure and sodium excretion were similar, whereas African Americans were more obese and had higher iothalamate GFRs. Renal cortical volumes did not differ, but medullary volumes adjusted for body size and age were higher in African Americans (32.3 ± 11.2 vs 25.1 ± 7.4 cm(3)/m(2) body surface area; P < 0.001). Sodium reabsorption and blood flows were higher in African Americans. Basal cortical deoxyhemoglobin values were similar between ethnic groups, whereas medullary R2* was higher in African Americans (39.7 ± 5.1 vs 36.3 ± 6.5/s; P = 0.02), but decreased to levels similar to whites after furosemide treatment. Levels of the circulating isoprostane prostaglandin F(2α) were higher in African Americans and daily urinary prostaglandin F(2α) excretion in African Americans correlated directly with renal blood flow (R = 0.71; P < 0.01). LIMITATIONS: Studies were limited to treated volunteers with normal kidney function without knowledge of prior nutrient intake. CONCLUSIONS: These data show for the first time that increased sodium reabsorption in obese African American patients with hypertension was associated with enlarged medullary volumes, functional hypoxia related to solute reabsorption, and a direct relationship between blood flows and urinary isoprostane levels. Our results support a model of increased oxygen consumption and oxidative stress in African Americans that may accelerate hypertension and target-organ injury compared with white patients with essential hypertension.