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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Contemporary management of giant renal and visceral arteriovenous fistulae.

PURPOSE: To evaluate our experience with treatment of giant arteriovenous fistulae (AVFs) involving the renal and visceral vasculature and assess outcomes. METHODS: Clinical data from 12 consecutive patients (10 women; median age 58 years, range 37-79) undergoing intervention for 14 giant renal/visceral AVFs over a 15-year period (1994-2008) were retrospectively reviewed. Only patients with extra-parenchymal, wide arteriovenous communications were included. Thirteen were located in the renal artery and one in the splenic artery. The etiology was most likely post-traumatic/iatrogenic in 6 patients, idiopathic in 4 (1 bilateral), congenital in 1 (bilateral), and one was associated with fibromuscular dysplasia. In 4 cases, the lesion was asymptomatic. RESULTS: Two large renal AVFs were treated with open surgery: one elective AV fistula repair early in our experience and the other an emergent nephrectomy for rupture. Twelve AV fistulae were closed successfully using endovascular techniques performed solely through the feeding vessel without cannulating the draining vein. All symptomatic patients, except one with continued dyspnea from cardiac causes, had complete symptomatic relief. There was no mortality. Morbidity included 2 access site hematomas that were managed conservatively. Loss of renal parenchyma ranged from 5% to 30%, but median serum creatinine levels remained stable. CONCLUSION: Endovascular treatment of giant renal/visceral AVFs is challenging but feasible and safe, with good organ preservation. Endovascular techniques have replaced open surgical repair as a first-line treatment for these challenging lesions.

Pelvic pseudotumor and pseudoaneurysm in a pediatric patient with moderate hemophilia B: successful management with arterial embolization and surgical excision.

Development of pseudotumors is an unusual complication of hemophilia. Treatment is controversial, especially in patients with large proximal lesions. Surgery, while curative, can be associated with massive intra-operative bleeding, infection and amputation. Arterial embolization of blood vessels supplying the pseudotumor may reduce these complications. Herein, we report a 14-year-old patient with moderate hemophilia B with a pelvic pseudotumor and pseudoaneurysm that failed conservative management with factor replacement alone. He was successfully treated with Bead Block and coil embolization followed by surgical extirpation of the lesion 24 hr later.

Outpatient vascular and interventional radiology practice from 2001-2008.

PURPOSE: To describe experience with an outpatient vascular interventional radiology (IR) practice with respect to number of patients seen, number of procedures performed, and number of imaging studies ordered in follow-up. MATERIALS AND METHODS: The outpatient vascular IR practice at the authors' institution was established in 2001 with two physicians spending one half-day per week; a third physician joined in 2004. A retrospective review was done of all patients seen by an interventional radiologist from 2001 to July 2008. The following data were collected for each physician per year: the number of new and established patients seen, the number and type of procedures performed, and the number and type of imaging studies ordered. Data are presented as mean ± standard deviation per physician per year and total number. RESULTS: In 2001, the average number of new patients seen was 61 ± 11 (total number = 122), which peaked in 2006 at 127 ± 28 (total number = 380). A similar trend occurred with the established patients. In 2001, the procedure performed with the greatest frequency was abdominal aortogram with stent placement, which started at 18 ± 2 (total number = 35) and peaked by 2006 at 37 ± 23 (total number = 122). The number of ancillary imaging studies ordered by each physician increased each year and by 2006 was nearly 93 ± 77 (total number = 278). CONCLUSIONS: A robust outpatient IR practice in vascular disease can be developed in 3-5 years with downstream imaging studies being ordered for the radiology department.

Results of single- and two-vessel mesenteric artery stents for chronic mesenteric ischemia.

BACKGROUND: To describe the outcomes of single- and two-vessel mesenteric artery stents in patients with chronic mesenteric ischemia (CMI). METHODS: We reviewed 101 patients (41 men and 60 women; mean age, 73 ± 13 years) treated with mesenteric artery stents for atherosclerotic CMI between 1998 and 2008. Clinical data and outcomes were reviewed in patients treated with single superior mesenteric artery (SMA) stent (group A) or two-vessel celiac artery (CA) and SMA stent (group B). Isolated CA stenting was analyzed as a separate group (group C). End-points were taken as differences in morbidity and mortality and freedom from recurrent symptoms and reinterventions. RESULTS: There were 61 patients in group A, 24 in group B, and 16 in group C. All three groups had similar demographics, cardiovascular risk factors, and clinical presentation. There were no differences in early mortality (2%, 4%, and 0%), morbidity (18%, 26%, and 12%), and symptom relief (95%, 78%, and 100%) between groups A, B, and C, respectively (p value was not significant). Mean follow-up was 41 ± 17 months. Freedom for reintervention at 1 and 3 years was similar among patients in groups A (86 ± 5% and 50 ± 9%), B (67 ± 11% and 67 ± 11%), and C (63 ± 13% and 63 ± 13%), respectively (p value was not significant). There were no significant differences in freedom from restenosis at 1 and 3 years among patients in groups A (54 ± 7% and 44 ± 9%), B (47 ± 12% and 39 ± 12%), and C (43 ± 13% and 34 ± 13%), respectively. Primary and secondary patency rates at 3 years were 57% and 96% for SMA and 61% and 87% for CA stents, respectively (p value was not significant). CA stent alone was associated with symptom recurrence in 6 of 16 patients (38%), as compared with the recurrence rate of 18% (11 of 61) in patients who underwent SMA stent placement (p = 0.06). CONCLUSION: Two-vessel CA and SMA stenting do not reduce the incidence of recurrent symptoms or reinterventions when compared with single-vessel SMA stents in patients with CMI. CA stent alone carries a high risk of recurrence.

Use of kissing embolic protection devices in the treatment of early bifurcation renal artery stenosis: a case report.

Renal artery stenosis (RAS) is a progressive disease that may cause hypertension and chronic renal insufficiency. Percutaneous renal artery angioplasty with stent placement is a well-recognized treatment for atherosclerotic RAS. It can infrequently involve the bifurcation, and treatment of this stenosis has been described using bare metal and drug-eluting stents deployed simultaneously in a kissing fashion. Atheroembolism is believed to be caused by the release of microscopic plaque fragments and cholesterol crystals from the RAS or atherosclerotic aorta. Herein, the authors describe the use of a kissing embolic protection device technique during renal artery stent placement.

Proteomic profiling in early venous stenosis formation in a porcine model of hemodialysis graft.

PURPOSE: To use proteomic analysis to identify up- and downregulated proteins in early venous stenosis formation in a porcine model of hemodialysis graft failure. MATERIALS AND METHODS: Pigs had chronic renal insufficiency created by subtotal renal infarction caused by renal artery embolization. Arteriovenous polytetrafluoroethylene grafts were placed 28 days later and the animals were killed after a further 3 days (n = 4), 7 days (n = 4), or 14 days (n = 4). Proteomic analysis with isotope-coded affinity tags and multidimensional liquid chromatography followed by tandem mass spectrometry was performed on the venous stenosis and control vessels. Expression of proteins was further confirmed by Western blot analysis. The blood urea nitrogen (BUN) and creatinine levels were determined before renal artery embolization and at the time of graft placement. RESULTS: At graft placement, mean BUN and creatinine levels were significantly higher than before embolization (P < .05). Six proteins were identified that were common to all four animals at the same time point. Five proteins (alpha-fetoprotein, fetuin A, macrophage migration inhibitory factor, pyruvate dehydrogenase E1 component, and lactoferrin) were upregulated and one protein (decorin) was downregulated. Expression of macrophage migration inhibitory factor, alpha-fetoprotein, and lactoferrin was further validated with Western blotting. By day 14, lactoferrin and fetuin-A expression were increased significantly in early venous stenosis formation. CONCLUSIONS: Significantly increased expression of lactoferrin and fetuin-A were observed in early venous stenosis by day 14. Understanding the role of lactoferrin and fetuin-A in hemodialysis vascular access failure could help in improving outcomes in patients undergoing hemodialysis.

The use of magnetic resonance to evaluate tissue oxygenation in renal artery stenosis.

Vascular occlusive disease poses a threat to kidney viability, but whether the events leading to injury and eventual fibrosis actually entail reduced oxygenation and regional tissue ischemia is unknown. Answering this question has been difficult because of the lack of an adequate method to assess tissue oxygenation in humans. BOLD (blood oxygen-level-dependent) magnetic resonance imaging detects changes in tissue deoxyhemoglobin during maneuvers that affect oxygen consumption, therefore this technique was used to image and analyze cortical and medullary segments of 50 kidneys in 25 subjects undergoing magnetic resonance (MR) angiography to diagnose renal artery stenosis (RAS). Magnetic rate of relaxation (R2*) positively correlates with deoxyhemoglobin levels and was therefore used as a surrogate measure of tissue oxygenation. Furosemide was administered to examine the effect of inhibiting energy-dependent electrolyte transport on tissue oxygenation in subjects with renovascular disease. In 21 kidneys with normal nephrograms, administration of furosemide led to a 20% decrease in medullary R2* (P < 0.01) and an 11.2% decrease in cortical R2*. In normal-size kidneys downstream of high-grade renal arterial stenoses, R2* was elevated at baseline, but fell after furosemide. In contrast, atrophic kidneys beyond totally occluded renal arteries demonstrated low levels of R2* that did not change after furosemide. In kidneys with multiple arteries, localized renal artery stenoses produced focal elevations of R2*, suggesting areas of deoxyhemoglobin accumulation. These results suggest that BOLD MR coupled with a method to suppress tubular oxygen consumption can be used to evaluate regional tissue oxygenation in the human kidney affected by vascular occlusive disease.

Pharmacoangiographic evidence of the presence and anatomical dominance of accessory pudendal artery(s).

PURPOSE: Potency preservation is one of the principal concerns surrounding newer developments in the management of organ confined carcinoma prostate. Nerve sparing techniques may not solely preserve erectile function and it is known that vascular factors may be an etiology of the dysfunction. The role of accessory pudendal arteries in the etiology and prevention of erectile dysfunction after radical prostatectomy is at present unclear. We reviewed pudendal angiograms in patients with erectile dysfunction to evaluate the prevalence and importance of these vessels. MATERIALS AND METHODS: Selective pudendal pharmacoangiograms were obtained in 79 consecutive patients with a history of erectile dysfunction. The aim was to identify accessory pudendal arteries, their origin and their significance relative to all identifiable pudendal arteries and the dorsal penile artery with respect to penile arterial inflow. RESULTS: An accessory pudendal artery was identified in 28 (35%) of the patients. The most common origin was the obturator artery. In 15 of the 28 men (54%) in whom an accessory artery was identified it appeared angiographically to be the dominant penile artery. In 3 patients it was apparently the only major arterial inflow to the penis. CONCLUSIONS: Accessory pudendal arteries may be identifiable with pharmacoangiograms in approximately a third of all men. Because they may be the dominant source of blood supply to the penis in some cases, their preservation during radical prostatectomy could be critical to erectile function following radical prostatectomy.