Top 10 candidate aortic disease trials.

Aortic pathologies such as aneurysm, dissection and trauma are relatively common and potentially fatal diseases. Over the past two decades, we have experienced unprecedented technical and medical developments in the field. Despite this, there is a great need, and great opportunities, to further explore the area. In this review, we have identified important areas that need to be further studied and selected priority aortic disease trials. There is a pressing need to update the AAA natural history and the role for endovascular AAA repair as well as to define biomarkers and genetic risk factors as well as influence of gender for development and progression of aortic disease. A key limitation of contemporary treatment strategies of AAA is the lack of therapy directed at small AAA, to prevent AAA expansion and need for surgical repair, as well as to reduce the risk for aortic rupture. Currently, the most promising potential drug candidate to slow AAA growth is metformin, and RCTs to verify or reject this hypothesis are warranted. In addition, the role of endovascular treatment for ascending pathologies and for uncomplicated type B aortic dissection needs to be clarified.

Snorkel/chimney and fenestrated endografts for complex abdominal aortic aneurysms.

Complex endovascular aneurysm repair (EVAR) involves extension of the proximal aortic seal zone with preservation of branch vessel patency, thereby expanding the applicability of endografting from the infrarenal to the suprarenal aorta. Snorkel/chimney (Sn-EVAR) and fenestrated EVAR (f-EVAR) serve as the two most commonly utilized advanced endovascular techniques to combat hostile proximal neck anatomy. The purpose of this article is to describe the principles and evolution of these advanced endovascular strategies, technical considerations, and results of sn- and f-EVAR in the management of challenging neck anatomy in abdominal aortic aneurysm disease.

Rapamycin limits the growth of established experimental abdominal aortic aneurysms.

OBJECTIVES: Abdominal aortic aneurysm (AAA) is a chronic inflammatory disease affecting 4-8% of men older than 60 years. No pharmacologic strategies limit disease progression, aneurysm rupture, or aneurysm-related death. We examined the ability of rapamycin to limit the progression of established experimental AAAs. METHODS: AAAs were created in 10-12-week-old male C57BL/6J mice via the porcine pancreatic elastase (PPE) infusion method. Beginning 4 days after PPE infusion, mice were treated with rapamycin (5 mg/kg/day) or an equal volume of vehicle for 10 days. AAA progression was monitored by serial ultrasound examination. Aortae were harvested for histological analyses at sacrifice. RESULTS: Three days after PPE infusion, prior to vehicle or rapamycin treatment, aneurysms were enlarging at an equal rate between groups. In the rapamycin group, treatment reduced aortic enlargement by 38%, and 53% at 3 and 10 days, respectively. On histological analysis, medial elastin and smooth muscle cell populations were relatively preserved in the rapamycin group. Rapamycin treatment also reduced mural macrophage density and neoangiogenesis. CONCLUSION: Rapamycin limits the progression of established experimental aneurysms, increasing the translational potential of mechanistic target of rapamycin-related AAA inhibition strategies.

EVAR deployment in anatomically challenging necks outside the IFU.

OBJECTIVE: Treatment of abdominal aortic aneurysms with high-risk anatomy (neck length <10-15 mm, neck angle >60°) using commercially available devices has become increasingly common with expanding institutional experience. We examined whether placement of approved devices in short angled necks provides acceptable durability at early and intermediate time points. METHODS: A total of 218 patients (197 men, 21 women) at a single academic center underwent endovascular aneurysm repair (EVAR) with a commercially available device between January 2004 and December 2007. Available medical records, pre- and postoperative imaging, and clinical follow-up were retrospectively reviewed. Patients were divided into those with suitable anatomy (instructions for use, IFU) for EVAR and those with high-risk anatomic aneurysm characteristics (non-IFU). RESULTS: IFU (n = 143) patients underwent repair with Excluder (40%), AneuRx (34%), and Zenith (26%) devices, whereas non-IFU (n = 75) were preferentially treated with Zenith (57%) over Excluder (25%) and AneuRx (17%). Demographics and medical comorbidities between the groups were similar. Operative mortality was 1.4% (2.1% IFU, 0% non-IFU) with mean follow-up of 35 months (range 12-72). Non-IFU patients tended to have larger sac diameters (46.7% ≥60 mm) with shorter (30.7% ≤10 mm), conical (49.3%), and more angled (68% >60°) necks (all p < .05 compared with IFU patients). Operative characteristics revealed that the non-IFU patients were more likely to be treated utilizing suprarenal fixation devices, to require placement of proximal cuffs (13.3% vs. 2.1%, p = .003), and needed increased fluoroscopy time (31 vs. 25 minutes, p = .02). Contrast dose was similar between groups (IFU = 118 mL, non-IFU = 119 mL, p = .95). There were no early or late surgical conversions. Rates of migration, endoleak, need for reintervention, sac regression, and freedom from aneurysm-related death were similar between the groups (p > .05). CONCLUSIONS: EVAR may be performed safely in high-risk patients with unfavorable neck anatomy using particular commercially available endografts. In our experience, the preferential use of active suprarenal fixation and aggressive use of proximal cuffs is associated with optimal results in these settings. Mid-term outcomes are comparable with those achieved in patients with suitable anatomy using a similar range of EVAR devices. Careful and mandatory long-term follow-up will be necessary to confirm the benefit of treating these high-risk anatomic patients.

Impact of endovascular repair on open aortic aneurysm surgical training.

PURPOSE: The purpose of this study was to determine the impact of an endovascular stent-graft program on vascular training in open aortic aneurysm surgery. METHODS: The institutional and vascular surgery fellow experience in aortic aneurysm repair during a 6-year period was reviewed. The 3-year period before introduction of endovascular repair was compared with the 3-year period after introduction of endovascular repair. All patients undergoing abdominal aortic aneurysm (AAA) or thoracoabdominal aortic aneurysm repairs were entered prospectively into a vascular registry and retrospectively analyzed to evaluate the changing patterns in aortic aneurysm treatment and surgical training. RESULTS: Between July 1994 and June 2000, a total of 588 patients with AAA or thoracoabdominal aneurysms were treated at Stanford University Medical Center. There were 296 (50%) open infrarenal AAA repairs, 87 (15%) suprarenal AAA repairs, 47 (8%) thoracoabdominal aneurysm repairs, and 153 (26%) endovascular stent-grafts. The total number of aneurysms repaired per year by vascular fellows before the endovascular program was 71.3 +/- 4.9 (range, 68-77) and increased to 124.7 +/- 35.6 (range, 91-162) after introduction of endovascular repair (P <.05). This increase was primarily caused by the addition of endovascular stent-graft repairs by vascular fellows (51.0 +/- 29.0/year [range, 23-81]). There was no change in the number of open infrarenal aortic aneurysm repairs per year, 53.0 +/- 6.6 (range, 48-56) before endovascular repair versus 47.0 +/- 1.7 (range, 46-49) after (P = not significant). There was a significant increase in the number of suprarenal AAA repairs per year by vascular fellows, 10.0 +/- 1.0 (range, 9-11) before endovascular repair compared with 19.0 +/- 6.5 (range, 13-26) after (P <.05). There was no change in the number of thoracoabdominal aneurysm repairs per year between the two groups, 8.0 +/- 3.0 (range, 4-11) before endovascular repair compared with 7.6 +/- 2.3 (range, 5-9) after. CONCLUSIONS: Introduction of an endovascular aneurysm stent-graft program significantly increased the total number of aneurysms treated. Although the number of open aneurysm repairs has remained the same, the complexity of the open aneurysm experience has increased significantly for vascular fellows in training.

Duplex surveillance of abdominal aortic stent grafts.

Aortic stent grafting is gaining acceptance rapidly as a durable and effective alternative to open surgery for abdominal aortic aneurysms (AAA). Unlike follow-up after open surgical procedures, postplacement surveillance protocols are necessary to ensure long-term freedom from device failure or aneurysm rupture. Surveillance protocols incorporating duplex scanning are effective and may reduce overall postplacement expenses. Specific device or patient anatomic features may be prone to failure, and familiarity with each approved device is a prerequisite to the performance of effective device surveillance studies. Mechanisms of failure of aneurysm exclusion after device placement, or "endoleak," have been described and categorized. Endoleak significance is directly related to location, duration, and influence on AAA diameter. Endoleak type also determines when and whether additional interventions are indicated. Future progress in endovascular AAA exclusion will depend in large part on the reliability and utility of cost-effective postprocedure surveillance protocols incorporating duplex ultrasound imaging.

Spontaneous late carotid-cutaneous fistula following radical neck dissection: a case report.

The authors present an unusual case of a spontaneous carotid-cutaneous fistula occurring as a late complication 4 years after radical neck dissection and postoperative radiation therapy for tonsillar squamous cell carcinoma in a 50-year-old patient. The etiologic factors predisposing patients to carotid artery rupture following radical neck dissection and a surgical option for carotid artery reconstruction instead of ligation are discussed.

Will endovascular repair replace open surgery for abdominal aortic aneurysm repair?

OBJECTIVE: To evaluate of the impact of endovascular aneurysm repair on the rate of open surgical repair and on the overall treatment of abdominal aortic aneurysms (AAAs). METHODS: All patients with AAA who were treated during two consecutive 40-month periods were reviewed. During the first period, only open surgical repair was performed; during the subsequent 40 months, endovascular repair and open surgical repair were treatment options. RESULTS: A total of 727 patients with AAA were treated during the entire period. During the initial 40 months, 268 patients were treated with open surgical repair, including 216 infrarenal (81%), 43 complex (16%), and 9 ruptured (3%) aortic aneurysms. During the subsequent 40 months, 459 patients with AAA were treated (71% increase). There was no significant change in the number of patients undergoing open surgical repair and no significant difference in the rate of infrarenal (238 [77%]) and complex (51 [16%]) repairs. A total of 353 patients were referred for endovascular repair. Of these, 190 (54%) were considered candidates for endovascular repair based on computed tomography or arteriographic morphologic criteria. Analyzing a subgroup of 123 patients, the most common primary reasons for ineligibility for endovascular repair were related to morphology of the neck in 80 patients (65%) and of the iliac arteries in 35 patients (28%). A total of 149 patients underwent endovascular repair. Of these, the procedure was successful in 147 (99%), and 2 (1%) patients underwent surgical conversion. The hospital death rate was 0%, and the 30-day death rate was 1%. During a follow-up period of 1 to 39 months (mean 12 +/- 9), 21 secondary procedures to treat endoleak (20) or to maintain graft limb patency (1) were performed in 17 patients (11%). There were no aneurysm ruptures or aneurysm-related deaths. CONCLUSIONS: Endovascular repair appears to have augmented treatment options rather than replaced open surgical repair for patients with AAA. Patients who previously were not candidates for repair because of medical comorbidity may now be safely treated with endovascular repair.

Endovascular repair of abdominal aortic aneurysms: eligibility rate and impact on the rate of open repair.

OBJECTIVE: The purpose of this study was to determine the rate of eligibility among patients with abdominal aortic aneurysms (AAAs) considered for endovascular repair and to examine the effect of an endovascular program on the institutional pattern of AAA repair. METHODS: All patients evaluated for endovascular AAA repair since the inception of an endovascular program were reviewed for determination of eligibility rates and eventual treatment. Open AAA repairs were categorized as simple (uncomplicated infrarenal), complex (juxtarenal, suprarenal, thoracoabdominal, infected), or ruptured, and their rates before and after initiation of an endovascular program were compared. RESULTS: Over 3 years, 324 patients were considered for endovascular AAA repair; 176 (54%) were candidates, 138 (43%) were not candidates, and 10 (3%) did not complete the evaluation. The rate of eligibility increased significantly from 45% (66/148 patients) during the first half of this period to 63% (110/176 patients) during the second half (P <. 001). Candidates were significantly younger (74.4 +/- 7.6 years) than noncandidates (78.3 +/- 6.7 years) (P <.01), and their aneurysm diameter tended to be smaller (57.6 +/- 9.2 mm compared with 60.8 +/- 12.3 mm; P =.06). The most common reason for ineligibility was an inadequate proximal aortic neck. Of 176 candidates, 78% underwent endovascular repair, and 6% underwent open repair. Of 138 noncandidates, 56% underwent surgical repair. Over a period of 6 years, 542 patients with AAAs (429 simple, 86 complex, 27 ruptured) underwent open repair. The total number and ratio of simple to complex open repairs for nonruptured aneurysms during the 3 years before the initiation of the endovascular program (213 simple, 44 complex) were not significantly different from the repairs over the subsequent 3-year period (216 simple, 42 complex). Similarly, no difference in the total number and the ratio of simple to complex open repairs was found between the first and the second 18-month periods since the initiation of the endovascular program. CONCLUSIONS: The rate of eligibility of patients with AAA for endovascular repair appears to be higher than previously reported. The presence of an active endovascular program has not decreased the number or shifted the distribution of open AAA repair.

Open saphenectomy complications following lower extremity revascularization.

A review of saphenectomy site complications following lower extremity revascularization was conducted. Leg incisions used for 133 consecutive infrainguinal bypass procedures were categorized by location. Patient and procedural risk factors were analyzed for risk of wound complications. Procedure, limb and patient outcome were reported via life table analysis. Incisional wound complications followed 32/133 procedures (24%), including 15 groin, eight saphenectomy, five distal and four vein/distal incisions. There were five grade I and three grade II saphenectomy complications. Only weight (body mass index) predicted the likelihood of wound complication (P < 0.05). The 6-month primary patency rate was 79% (mean follow-up 22 months). Four-year assisted primary patency, limb salvage and survival rates were 75, 87 and 57%, respectively. Most bypass-related wound complications (24/32, 75%) involve arterial access incisions. Incisional complications are related to body mass index. Only 6% of GS vein bypass procedures develop saphenectomy site complications. Limiting saphenectomy size may not significantly reduce incisional morbidity following bypass grafting.

Dose-dependent limitation of arterial enlargement by the matrix metalloproteinase inhibitor RS-113,456.

BACKGROUND: Arterial diameter changes in response to flow. Chronic flow-mediated arterial enlargement may be mediated through metalloproteinase activity in the extracellular matrix of the arterial wall. We examined flow-mediated enlargement in the setting of increasing competitive matrix metalloproteinase (MMP) inhibition and with respect to gelatinase A and B expression and activity. METHODS: Left common femoral arteriovenous fistulas (AVFs) were created in dose-response (52) and time course (34) cohorts of rats. Dose-response rats received either vehicle alone or 12.5, 25, or 37. 5 mg/kg b.i.d. RS 113,456, a competitive MMP inhibitor. Heart rate, blood pressure, and weight were measured at intervals following AVF construction. Aortic and common iliac diameters were measured on postoperative day (POD) 21. Untreated time course rats were sacrificed on PODs 0 (no AVF), 3, 7, 14, and 21. Aortic diameter was measured and the vessels were harvested for tissue analysis. Equal amounts of aortic RNA underwent reverse transcription and polymerase chain reaction with primers for MMP-2, MMP-9, and GAPDH. Zymography was performed on iliac artery tissue to measure gelatinolytic activity. RESULTS: A significant, stepwise reduction in flow-mediated aortic and left common iliac enlargement following left femoral AVF creation was noted with progressively higher doses of RS 113,456 without apparent hemodynamic or toxic effects. Right common iliac diameter was unchanged. Over 21 days following AVF creation, there was an upward trend in expression and activity for MMP-2 not evident for MMP-9. CONCLUSION: Flow-mediated arterial enlargement is limited by competitive MMP inhibition in a dose-dependent fashion. MMP-dependent flow-mediated enlargement may involve differential expression and activity of MMP-2 and MMP-9.

Reoperation for carotid stenosis is as safe as primary carotid endarterectomy.

PURPOSE: Patients with recurrent carotid artery stenosis are sometimes referred for carotid angioplasty and stenting because of reports that carotid reoperation has a higher complication rate than primary carotid endarterectomy. The purpose of this study was to determine whether a difference exists between outcomes of primary carotid endarterectomy and reoperative carotid surgery. METHODS: Medical records were reviewed for all carotid operations performed from September 1993 through March 1998 by vascular surgery faculty at a single academic center. The results of primary carotid endarterectomy and operation for recurrent carotid stenosis were compared. RESULTS: A total of 390 operations were performed on 352 patients. Indications for primary carotid endarterectomy (n = 350) were asymptomatic high-grade stenosis in 42% of the cases, amaurosis fugax and transient ischemic symptoms in 35%, global symptoms in 14%, and previous stroke in 9%. Indications for reoperative carotid surgery (n = 40) were symptomatic recurrent lesions in 50% of the cases and progressive high-grade asymptomatic stenoses in 50%. The results of primary carotid endarterectomy were no postoperative deaths, an overall stroke rate of 1.1% (three postoperative strokes, one preoperative stroke after angiography), and no permanent cranial nerve deficits. The results of operations for recurrent carotid stenosis were no postoperative deaths, no postoperative strokes, and no permanent cranial nerve deficits. In the primary carotid endarterectomy group, the mean hospital length of stay was 2.6 +/- 1. 1 days and the mean hospital cost was $9700. In the reoperative group, the mean length of stay was 2.6 +/- 1.5 days and the mean cost was $13,700. The higher cost of redo surgery is accounted for by a higher preoperative cerebral angiography rate (90%) in redo cases as compared with primary endarterectomy (40%). CONCLUSION: In this series of 390 carotid operations, the procedure-related stroke/death rate was 0.8%. There were no differences between the stroke-death rates after primary carotid endarterectomy and operation for recurrent carotid stenosis. Operation for recurrent carotid stenosis is as safe and effective as primary carotid endarterectomy and should continue to be standard treatment.

In vivo flow-independent T2 measurements of superior mesenteric vein blood in diagnosis of chronic mesenteric ischemia: a preliminary evaluation.

RATIONALE AND OBJECTIVES: The authors attempted to determine whether the T2 relaxation time of superior mesenteric vein (SMV) blood would decrease in patients with chronic mesenteric ischemia after a meal. MATERIALS AND METHODS: Thirty-two patients without chronic mesenteric ischemia and eight patients with symptomatic chronic mesenteric ischemia underwent magnetic resonance (MR) imaging. All examinations were performed with a 1.5-T unit, a modified Carr-Purcell-Meiboom-Gill sequence, final section-selective pulse of 180 degrees, and spiral readout gradients. Measurements of SMV blood T2 were obtained after at least 6 hours of fasting and 15 and 35 minutes after ingestion of 240 mL of a liquid nutritional supplement. Maximal change of the SMV blood T2 was expressed as a percentage of the fasting T2 in all patients. RESULTS: In control patients, SMV blood T2 increased postprandially by 9.4% +/- 1.3 (95% confidence level; range, 6.8%-11.9%) (data range, -7.3% to 25.6%) compared with fasting T2. In symptomatic patients, SMV blood T2 decreased postprandially by 15.8% +/- 2.2 (95% confidence level; range, -20.1% to -10.7%) (data range, -7.9% to -25.3%). The difference between the two groups was statistically significant (P < .0001 by Student unpaired t test). CONCLUSION: Measurement of SMV blood T2 is a promising test for chronic mesenteric ischemia diagnosis. Therefore, conversion of T2 measurements to estimate oxygen saturation may not be necessary for all cases of this clinical indication.

Matrix metalloproteinase inhibition limits arterial enlargements in a rodent arteriovenous fistula model.

BACKGROUND: We administered a specific, nonselective matrix metalloproteinase (MMP) inhibitor (RS-113,456) to examine the effect of MMP inhibition on flow-mediated arterial enlargement in a rodent arteriovenous fistula (AVF) model. METHODS: Four groups of male Sprague-Dawley rats were created: sham (sham operated; n = 10), control (2.0 mm left common femoral AVF alone; n = 16), vehicle (AVF plus 0.5 mL vehicle orally twice a day; n = 20), and treatment (AVF plus 25 mg/kg RS-113,456 in 0.5 mL vehicle orally twice a day; n = 16). Heart rate, mean arterial pressure, and body weight were recorded on postoperative days 0, 7, 14, and 21. On day 21, AVF patency was confirmed, the infrarenal aorta and common iliac arteries were exposed, blood flow velocity and external diameter were measured, and wall shear stress (WSS) was calculated. Analysis was performed by paired, two-tailed Student t test, one-way analysis of variance, and the Bonferroni/Dunn procedure for post hoc testing. RESULTS: Heat rate, mean arterial pressure, and weight did not vary at any time between groups. Aortic and left iliac diameter was larger in the AVF groups than in sham groups (P < .001), and control and vehicle groups were larger than treatment groups (P < .0001). Changes in aortic and left iliac flow were also significant (AVF was more than sham and control, and vehicle was more than treatment). No difference in aortic and left iliac artery velocity and WSS or right iliac diameter, velocity, flow, or WSS was observed between groups. CONCLUSIONS: MMP inhibition diminishes flow-mediated arterial enlargement in the rat AVF model.

Limb salvage surgery in spinal cord injury patients.

Advances in the care and rehabilitation of patients with spinal cord injuries (SCI) have resulted in extended survival following injury. Increasingly, we are faced with difficult chronic lower extremity ischemic complications in SCI patients. Recognizing limitations associated with amputation in these nonambulatory patients, we report the preliminary results of a program of selective limb salvage via arterial reconstructive surgery. Retrospective chart review was performed on the records of the Veterans Affairs Palo Alto Health Care System SCI unit. Since 1989, 15 revascularization procedures were identified in 10 SCI patients. All patients suffered from ischemic ulceration and/or gangrene. Procedures performed included femorotibial bypass (8), aortofemoral bypass (4), femoro-femoral bypass (2), and axillobifemoral bypass (AXF) (1). All patients were men. The mean age was 56 (range 43-73). Follow-up was available on 10 procedures performed in seven patients since 1992. Mean follow-up was 17 months. One patient died 3 months following distal bypass. The AXF occluded within 1 month. One distal bypass occluded in the immediate postoperative period and could not be salvaged. All other grafts remain patent, and all wounds have healed following successful bypass. One patient developed pressure ulceration following AXF grafting due to postoperative upper extremity limitations. No other complications were encountered. Standard arterial reconstructive procedures can be performed safely and successfully in SCI patients, despite diminished limb blood flow due to inactivity, and atrophic arteries, muscle, and fascia. Axillobifemoral bypass grafting may not be suitable in SCI due to requirements for upper extremity-based mobility. Confirmation of benefit of limb salvage versus amputation awaits comparison between patients eligible for either procedure.

Use of outpatient preoperative evaluation to decrease length of stay for vascular surgery.

UNLABELLED: Interventions that decrease perioperative length of stay can result in considerable cost-savings. This study assesses the impact of same-day admission using outpatient preoperative evaluation on the lengths of stay and hospital costs for patients who underwent carotid end-arterectomy (CEA) or lower extremity revascularization (LER). Patient characteristics and length of stay were compared for two 1-yr periods before and after outpatient preoperative evaluation had been implemented. There were no significant differences before and after the initiation of outpatient preoperative evaluation in the CEA and LER groups in mean age and ASA physical status distributions. The average preoperative length of stay decreased significantly from 7.0 to 1.9 days in the CEA group and from 9.0 to 2.8 days in the LER group. This reduction in the length of stay was associated with a cost-savings of $900 per patient and did not have an adverse effect on patient outcome. We conclude that outpatient preoperative evaluation clinics reduce the cost and length of stay in vascular surgery patients. IMPLICATIONS: We found that outpatient preoperative evaluation and same-day admission were associated with a decrease of 4.5 days in the preoperative length of stay for carotid endarterectomy and lower-extremity revascularization. This was not accompanied by increased mortality and led to hospital cost-savings of approximately $900 per patient.

Chronic mesenteric ischemia: use of in vivo MR imaging measurements of blood oxygen saturation in the superior mesenteric vein for diagnosis.

PURPOSE: To determine if dogs and humans with chronic mesenteric ischemia demonstrate a decrease in the percentage of oxygenated hemoglobin (%HbO2) in the superior mesenteric vein (SMV) after a meal. MATERIALS AND METHODS: In 10 dogs, ameroid rings were surgically implanted around the superior mesenteric arteries to create gradual stenosis. Pre- and postoperative angiograms and pre- and postprandial magnetic resonance (MR) oximetry measurements of the SMV %HbO2, with flow-independent T2 measurements of venous blood, were obtained at different times. In 10 patients with atherosclerotic disease and six patients with symptomatic chronic mesenteric ischemia, the same measurements were obtained after at least 6 hours of fasting and at 15, 35, and 45 minutes after ingestion of a liquid nutritional supplement. RESULTS: In seven dogs, the postprandial SMV %HbO2 increased an average of 2.5% +/- 0.8 before surgery and decreased an average of 6.3% +/- 2.1 when hemodynamically significant (>70%) stenosis of the superior mesenteric artery developed 7-14 days after surgery. In the 10 patients without ischemia, the SMV %HbO2 increased by 4.6% +/- 0.6, whereas in the symptomatic patients a postprandial decrease of 8.8% +/- 0.7 occurred (P < .0001). CONCLUSION: Measurement of the SMV %HbO2 with MR oximetry is a promising test for diagnosis of chronic mesenteric ischemia.