Mesenteric duplex scanning: a blinded prospective study

Median Arcuate Ligament Syndrome: Where Are We Today?

Median arcuate ligament syndrome, or celiac artery compression syndrome (eponym: Dunbar syndrome), has historically been attributed to pathophysiologic vascular compression causing downstream ischemic symptoms of the organs supplied by the celiac trunk. However, the more we learn about the histology, clinical presentation, and treatment outcomes, health care providers are increasingly correlating the symptoms of MALS with the long-term, repetitive compression of the celiac ganglion rather than the celiac trunk. This article provides a comprehensive review of current MALS literature, emphasizing the multidisciplinary approach these patients require in all phases of their care. With most patients with MALS waiting an average of 10.5 months to 2.6 years, 9, 10 our need for better diagnostic protocols and clearer understanding of the pathophysiology of the disease is paramount. Further investigation into patient outcomes, associated conditions, and linked pathophysiology would help better characterize this disease with hopes of moving it from a diagnosis of exclusion to one of standard work-up with decreased time to treatment and symptom relief for patients.

Mesenteric Ischemia

Mesenteric ischemia occurs when perfusion of the visceral organs fails to meet normal metabolic requirements and subsequently results in abdominal symptoms such as diffuse postprandial pain, peritonitis, food fear, and weight loss. While generally divided into acute and chronic manifestations, mesenteric ischemia is commonly misdiagnosed at initial presentation due to the significant overlap with symptoms of other abdominal pathologies. Prompt recognition and diagnosis, mesenteric revascularization, and critical care management remain the mainstay of treatment in these patients for optimal outcomes. This review will highlight acute versus chronic mesenteric ischemia, their etiology, diagnostic criteria, treatment options, and will emphasize the joint role of the gastrointestinal and vascular surgeon in the timely management of this condition to prevent devastating outcomes.

Comparative outcomes of open mesenteric bypass after a failed endovascular or open mesenteric revascularization for chronic mesenteric ischemia

INTRODUCTION

Clinical practice guidelines have recommended an endovascular-first approach (ENDO) for the management of patients with chronic mesenteric ischemia (CMI), whereas an open mesenteric bypass (OMB) is proposed for subjects deemed to be poor ENDO candidates. However, the impact of a previous failed endovascular or open mesenteric reconstruction on a subsequent OMB is unknown. Accordingly, this study was designed to examine the results of a remedial OMB (R-OMB) after a failed ENDO or a primary OMB (P-OMB) for patients with recurrent CMI.

METHODS

All patients who underwent an OMB from 2002 to 2022 at the University of Florida were reviewed. Outcomes after an R-OMB (ie, history of a failed ENDO or P-OMB) and P-OMB were compared. The primary end point was 30-day mortality, whereas secondary outcomes included complications, reintervention, and survival. The Kaplan-Meier methodology was used to estimate freedom from reintervention and all-cause mortality, whereas multivariable Cox proportional hazards modeling identified predictors of death.

RESULTS

A total of 145 OMB procedures (R-OMB, n = 48 [33%]; P-OMB, n = 97 [67%]) were analyzed. A majority of R-OMB operations were performed for a failed stent (prior ENDO, n = 39 [81%]; prior OMB, n = 9 [19%]). R-OMB patients were generally younger (66 ± 9 years vs P-OMB, 69 ± 11 years; P = .09) and had lower incidence of smoking exposure (29% vs P-OMB, 48%; P = .07); however, there were no other differences in demographics or comorbidities. R-OMB was associated with less intraoperative transfusion (0.6 units vs P-OMB, 1.4 units; P = .01), but there were no differences in conduit choice or bypass configuration.The overall 30-day mortality and complication rates were 7% (n = 10/145) and 53% (n = 77/145), respectively, with no difference between the groups. Notably, R-OMB had decreased cardiac (6% vs P-OMB, 21%; P < .01) and bleeding complication rates (2% vs P-OMB, 15%; P = .01). The freedom from reintervention (1 and 5 years: R-OMB: 95% ± 4%, 83% ± 9% vs P-OMB: 97% ± 2%, 93% ± 5%, respectively; log-rank P = .21) and survival (1 and 5 years: R-OMB: 82% ± 6%, 68% ± 9% vs P-OMB: 84% ± 4%, 66% ± 7%; P = .91) were similar. Independent predictors of all-cause mortality included new postoperative hemodialysis requirement (hazard ratio [HR], 7.4, 95% confidence interval [CI], 3.1-17.3; P < .001), pulmonary (HR, 2.7, 95% CI, 1.4-5.3; P = .004) and cardiac (HR, 2.4, 95% CI, 1.1-5.1; P = .04) complications, and female sex (HR, 2.1, 95% CI, 1.03-4.8; P = .04). Notably, R-OMB was not a predictor of death.

CONCLUSIONS

The perioperative and longer-term outcomes for a remedial OMB after a failed intraluminal stent or previous open bypass appear to be comparable to a P-OMB. These findings support the recently updated clinical practice guideline recommendations for an endovascular-first approach to treating recurrent CMI due to the significant perioperative complication risk of OMB. However, among the subset of patients deemed ineligible for endoluminal reconstruction after failed mesenteric revascularization, R-OMB results appear to be acceptable and highlight the utility of this strategy in selected patients.

Mesenteric and renal arterial duplex ultrasound: A review

Duplex ultrasound examinations of the mesenteric and renal circulations are commonly used to detect disease as well as to follow up patients after open surgery or endovascular intervention. The aims of this review were to present essential elements of these duplex ultrasound examinations as well as conduct a literature review of diagnostic criteria. Documentation of appropriate images and data will aid in an accurate interpretation. Spectral Doppler waveforms from various segments of these arterial systems can contribute both direct and indirect evidence of the presence of disease. Various studies have validated the duplex ultrasound diagnostic criteria which more recently have expanded to include specific criteria for stented vessels. This review presents a summary of the fundamental exam components and diagnostic criteria utilized for mesenteric and renal duplex ultrasound.

Measuring gut perfusion and blood flow in neonates using ultrasound Doppler of the superior mesenteric artery: a narrative review

The gut is a relatively silent organ in utero but takes on a major role after birth for the absorption and digestion of feed for adequate nutrition and growth. The neonatal circulation undergoes a transition period after birth, and gut perfusion increases rapidly to satisfy the oxygen demand and consumption. If this process is compromised at any stage, preterm and fetal growth restricted infants are at particular risk of gut tissue injury secondary to hypoxia, leading to necrotizing enterocolitis. Feeding can also be a challenge in these high-risk groups due to gut dysmotility. Superior mesenteric artery (SMA) Doppler is a safe, bedside investigation that could rapidly aid clinicians with feeding strategies and in monitoring high-risk infants. This article aims to establish normal patterns of gut blood flow velocity in neonates using SMA Doppler and reviews how it might be used clinically in pathologic states.

Abdominal Vascular Evaluation

The vascular lab (VL) is instrumental in diagnosing vascular diseases such as renal artery stenosis and mesenteric ischemia or following a patient after transjugular intrahepatic portal systemic shunt (TIPS) creation. This article discusses indications, protocol, and diagnostic criteria for abdominal vascular ultrasound. The vascular lab can be used to investigate pathology in the abdomen either as a preliminary screening tool to evaluate for a pathology such as mesenteric artery stenosis in a patient with food fear and weight loss, renal artery stenosis in a patient with refractory hypertension or renal failure, or as a diagnostic tool in follow up after a patient has undergone a transjugular intrahepatic portal systemic shunt (TIPS) for portal hypertension. The technical success of duplex ultrasonography of the abdomen can be compromised by respiratory motion, obesity, and intestinal gas. Therefore, duplex scanning is performed in the fasting state particularly in elective outpatient cases. In emergent cases when pathology such as acute mesenteric ischemia is suspected evaluation with CT angiography may be best.

Laparoscopic Surgery for Median Arcuate Ligament Syndrome (MALS): A Prospective Cohort of 52 Patients

Background

The selection of patients with MALS for surgical treatment depends upon the reliability of the symptom interpretation and the diagnostic work-up. We aimed to follow up the results of the laparoscopic decompression of the patients with MALS.

Patients and Methods

In a single-center, 52 consecutive MALS patients were followed-up, prospectively, after transperitoneal laparoscopic decompression. MALS was diagnosed with a computed tomography angiography (CTA) verified stenosis, ≥50% of the celiac artery (CA), and with duplex ultrasound, a peak systolic velocity (PSV) ≥2.0 m/s. Postoperative, CTA, and duplex ultrasound were performed, and the patients were followed-up at 3, 6, 12 months, and yearly after that.

Results

Mean age of the patients was 47 ±21 years, and 65% were females. The patients had a mean weight loss of 8.4 ±7.2 kg. Fifty-one patients had the laparoscopic operation with a mean operation time of 102 ± 28 minutes. Forty-seven patients (90%) achieved relief from the symptoms either completely (67%) or partially (23%) at 3–6 months of follow-up. Significant improvement in postoperative PSV was found compared to the preoperative values, p<0.001. Five patients (10%) with no immediate effect of the operation, but two of them became free from symptoms during the mean study follow-up of 2.4 ± 2 years. Five patients (10%) had operative complications, including one trocar injury to the liver, one pneumothorax, and three cases of bleeding from the branches of CA. Two patients died of cancer disease during the study period. Only two patients (4%) had symptoms relapse, both later treated successfully.

Conclusion

Laparoscopic transperitoneal decompression provides most of the patients a persistent relief from MALS symptoms.

Ultrasound imaging for assessing functions of the GI tract

OBJECTIVE

In the following review we outline how ultrasound can be used to measure physiological processes in the gastrointestinal tract.

APPROACH

We have investigated the potential of ultrasound in assessing gastrointestinal physiology including original research regarding both basic methodology and clinical applications.

MAIN RESULTS

Our main findings show the use of ultrasound to study esophageal motility, measure volume and contractility of the stomach, assess motility, wall thickness, and perfusion of the small bowel, and evaluate wall vascularization and diameters of the large bowel.

SIGNIFICANCE

Ultrasound is a widely accessible technology that can be used for both scientific and clinical purposes. Being radiation-free and user friendly, the examination can be frequently repeated enabling longitudinal studies. Furthermore, it does not influence normal GI physiology, thus being useful to estimate motility and subtle changes in physiology. Accordingly, ultrasound scanning and physiological measurements may make a big difference for the scientist and the doctor; and for the patients who receive an efficient work-up.

Noncontrast Magnetic Resonance Angiography in the Era of Nephrogenic Systemic Fibrosis and Gadolinium Deposition

ABSTRACT

Gadolinium-based contrast agents for clinical magnetic resonance imaging are overall safe. However, the discovery of nephrogenic systemic fibrosis in patients with severe renal impairment and gadolinium deposition in patients receiving contrast have generated developments in contrast-free imaging of the vasculature, that is, noncontrast magnetic resonance angiography. This article presents an update on noncontrast magnetic resonance angiography techniques, with comparison to other imaging alternatives. Potential benefits and challenges to implementation, and evidence to date for various clinical applications are discussed.

Usefulness of Transesophageal Echocardiography in the Evaluation of Celiac Trunk and Superior Mesenteric Artery Involvement in Acute Aortic Dissection

Mesenteric ischemia is a serious complication of acute aortic dissection (AAD), and its early diagnosis is vital for prognosis and appropriate treatment indication. Arteries affected by this complication are the celiac trunk and superior mesenteric artery, and their evaluation is usually based on computed tomographic angiography. Transesophageal echocardiography is also a useful technique for diagnosing AAD and is essential in monitoring surgical or endovascular treatment when computed tomographic angiography is not available. However, the usefulness of transesophageal echocardiography for evaluating celiac trunk and superior mesenteric artery involvement and mesenteric ischemia mechanisms in AAD is not well established. Real-time information on mesenteric malperfusion is needed at the bedside, in primary care facilities, and in the operating room to achieve prompt diagnosis and better therapeutic management. The aims of this review are to assess the role of TEE to diagnose celiac trunk and superior mesenteric artery involvement in AAD, determine the mechanisms that can cause flow obstruction in patients with mesenteric ischemia, and analyze possible implications in the treatment of this complication.

Chronic mesenteric ischemia: Clinical practice guidelines from the Society for Vascular Surgery

BACKGROUND

Chronic mesenteric ischemia (CMI) results from the inability to achieve adequate postprandial intestinal blood flow, usually from atherosclerotic occlusive disease at the origins of the mesenteric vessels. Patients typically present with postprandial pain, food fear, and weight loss, although they can present with acute mesenteric ischemia and bowel infarction. The diagnosis requires a combination of the appropriate clinical symptoms and significant mesenteric artery occlusive disease, although it is often delayed given the spectrum of gastrointestinal disorders associated with abdominal pain and weight loss. The treatment goals include relieving the presenting symptoms, preventing progression to acute mesenteric ischemia, and improving overall quality of life. These practice guidelines were developed to provide the best possible evidence for the diagnosis and treatment of patients with CMI from atherosclerosis.

METHODS

The Society for Vascular Surgery established a committee composed of vascular surgeons and individuals experienced with evidence-based reviews. The committee focused on six specific areas, including the diagnostic evaluation, indications for treatment, choice of treatment, perioperative evaluation, endovascular/open revascularization, and surveillance/remediation. A formal systematic review was performed by the evidence team to identify the optimal technique for revascularization. Specific practice recommendations were developed using the Grading of Recommendations Assessment, Development, and Evaluation system based on review of literature, the strength of the data, and consensus.

RESULTS

Patients with symptoms consistent with CMI should undergo an expedited workup, including a computed tomography arteriogram, to exclude other potential causes. The diagnosis is supported by significant arterial occlusive disease in the mesenteric vessels, particularly the superior mesenteric artery. Treatment requires revascularization with the primary target being the superior mesenteric artery. Endovascular revascularization with a balloon-expandable covered intraluminal stent is the recommended initial treatment with open repair reserved for select younger patients and those who are not endovascular candidates. Long-term follow-up and surveillance are recommended after revascularization and for asymptomatic patients with severe mesenteric occlusive disease. Patient with recurrent symptoms after revascularization owing to recurrent stenoses should be treated with an endovascular-first approach, similar to the de novo lesion.

CONCLUSIONS

These practice guidelines were developed based on the best available evidence. They should help to optimize the care of patients with CMI. Multiple areas for future research were identified.

The radiologist's guide to duplex ultrasound assessment of chronic mesenteric ischemia

OBJECTIVE

This article reviews the relevant anatomy and physiology of the mesenteric vasculature, familiarizes the radiologist with the accepted diagnostic criteria for mesenteric artery stenosis and its role in the diagnosis of chronic mesenteric ischemia, describes Doppler imaging techniques, and provides protocols for the assessment and surveillance of the mesenteric vasculature before and after revascularization. It also discusses expected changes following revascularization and reviews common post-procedural complications.

RESULTS

Duplex sonography plays an important role in the diagnosis and management of chronic mesenteric ischemia (CMI). Establishing a successful diagnosis is dependent upon knowledge of mesenteric arterial anatomy and physiology as well as sufficient expertise in image optimization and scanning techniques. Although there has been a trend toward utilization of other noninvasive [computed tomographic angiography (CTA), magnetic resonance angiography (MRA), and invasive (digital subtraction angiography (DSA)] imaging modalities for assessment of the mesenteric vasculature, a new era of "imaging wisely" raises legitimate concerns about the effects of ionizing radiation as well as potential effects of CT and MR contrast agents. These concerns are obviated by the use of ultrasound, and recently developed techniques, such as contrast-enhanced ultrasound and vascular applications focused on the evaluation of slow flow, have revealed the vast potential of vascular ultrasound in the evaluation of chronic mesenteric ischemia.

CONCLUSION

Duplex sonography is a cost-effective and powerful tool that can be utilized for the accurate assessment of mesenteric vascular pathology, specifically mesenteric arterial stenosis, and for the evaluation of mesenteric arterial system post revascularization.

Perioperative Microcirculatory Changes Detected with Gastroscopy Assisted Laser Doppler Flowmetry and Visible Light Spectroscopy in Patients with Median Arcuate Ligament Syndrome

Purpose

Physiological tests may aid in diagnosing median arcuate ligament syndrome (MALS). MALS is a symptomatic compression of the celiac artery causing symptoms similar to chronic mesenteric ischemia (CMI) of atherosclerotic etiology. Simultaneous use of visible light spectroscopy (VLS) and laser doppler flowmetry (LDF) during upper endoscopy may detect microcirculatory changes in these patients.

Patients and Methods

In a single-center, prospective comparative cohort, 25 patients were evaluated for MALS. Patients with a consensus diagnosis of MALS (n=15) underwent a gastroscopy assisted, transmucosal microcirculatory assessment with LDF and VLS. Results were compared to individuals with normal intestinal circulation (n=38) evaluated with duplex ultrasonography, and to patients with chronic mesenteric ischemia (n=32). Treatment response was evaluated clinically at 1, 3, 6, and 12 months, and with ultrasound, VLS and LDF at three months. Health-related quality of life (QoL) was assessed with Euroqol (EQ-5D-5L), preoperatively, and 12 months postoperatively.

Results

Preoperative mean transmucosal oxygen saturation was significantly lower in patients with MALS (SO₂ 76±6), as compared to healthy individuals (SO₂ 81±4), p=0.02. An overall significant improvement in SO₂ after surgical decompression of the celiac artery was found (SO₂ 81±3.7, p=0.05). Eleven (92%) patients with clinical improvement after laparoscopic decompression had a definitive diagnosis of MALS. Median follow-up was 18 months (4–24 months). Four of the five dimensions investigated with EQ-5D-5L improved.

Conclusion

VLS detected a significantly lower baseline transmucosal SO₂ in patients with MALS as compared to control subjects with normal intestinal circulation. An improvement in SO₂ after laparoscopic decompression was found, supporting a possible ischemic etiology in our patient population.

Interpretation of peripheral arterial and venous Doppler waveforms: A consensus statement from the Society for Vascular Medicine and Society for Vascular Ultrasound

This expert consensus statement on the interpretation of peripheral arterial and venous spectral Doppler waveforms was jointly commissioned by the Society for Vascular Medicine (SVM) and the Society for Vascular Ultrasound (SVU). The consensus statement proposes a standardized nomenclature for arterial and venous spectral Doppler waveforms using a framework of key major descriptors and additional modifier terms. These key major descriptors and additional modifier terms are presented alongside representative Doppler waveforms, and nomenclature tables provide context by listing previous alternate terms to be replaced by the new major descriptors and modifiers. Finally, the document reviews Doppler waveform alterations with physiologic changes and disease states, provides optimization techniques for waveform acquisition and display, and provides practical guidance for incorporating the proposed nomenclature into the final interpretation report.

European guidelines on chronic mesenteric ischaemia - joint United European Gastroenterology, European Association for Gastroenterology, Endoscopy and Nutrition, European Society of Gastrointestinal and Abdominal Radiology, Netherlands Association of Hepatogastroenterologists, Hellenic Society of Gastroenterology, Cardiovascular and Interventional Radiological Society of Europe, and Dutch Mesenteric Ischemia Study group clinical guidelines on the diagnosis and treatment of patients with chronic mesenteric ischaemia

Chronic mesenteric ischaemia is a severe and incapacitating disease, causing complaints of post-prandial pain, fear of eating and weight loss. Even though chronic mesenteric ischaemia may progress to acute mesenteric ischaemia, chronic mesenteric ischaemia remains an underappreciated and undertreated disease entity. Probable explanations are the lack of knowledge and awareness among physicians and the lack of a gold standard diagnostic test. The underappreciation of this disease results in diagnostic delays, underdiagnosis and undertreating of patients with chronic mesenteric ischaemia, potentially resulting in fatal acute mesenteric ischaemia. This guideline provides a comprehensive overview and repository of the current evidence and multidisciplinary expert agreement on pertinent issues regarding diagnosis and treatment, and provides guidance in the multidisciplinary field of chronic mesenteric ischaemia.

Post-esophagectomy Symptomatic Dunbar Syndrome: A rare diagnosis of abdominal pain after surgery

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Median Arcuate Ligament syndrome (MALS) is also known as Durban syndrome.

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MALS is a rare condition.

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MALS must be considered in case of refractory post-surgical abdominal pain.

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Angiotomography is accessible and reliable for making the diagnosis.

Introduction

Dunbar syndrome is a rare anatomical abnormality characterized by the extrinsic compression of the celiac trunk by the median arcuate ligament (MAL). Though it is rarely misdiagnosed, the clinical diagnosis may be difficult, especially after complex visceral surgery such as esophagectomy.

Presentation of case

A 62-year-old male patient with a squamous cell carcinoma of the distal esophagus, placed under trimodal treatment (chemotherapy, radiotherapy followed by hybrid minimal invasive 2-field esophagectomy) presented with abdominal pain refractory to analgesics, anti-spasmodic, opioids, and neuronal celiac plexus ablation in the late post-operative period. He was diagnosed with extrinsic celiac trunk compression based on abdominal angiotomography findings. Retrospectively, similar images were found in conventional abdominal tomography at pre-operative staging, but this time, the patient had only dysphagia. After surgical treatment of MAL, the patient had total relief of pain and symptoms.

Discussion

Abdominal pain after complex surgical procedures is very frequent and its investigation is mandatory, even more after refractory clinical management. Dunbar syndrome is related to ambiguous abdominal pain. It is uncommon and its diagnosis with angiotomography is accessible.

Conclusion

Vascular disorders should be investigated in cases of abdominal pain after complex surgical procedures.

Doppler ultrasonographic evaluation of celiac and mesenteric arteries in subjects with sickle cell disease

Vasculopathy, as occurring in sickle cell disease (SCD), can affect celiac and mesenteric arteries and result in stenosis, with elevated peak systolic velocity (PSV) on Doppler ultrasonography. In six subjects with confirmed SCD in steady state, routine Doppler ultrasonographic examination discovered features of celiac artery (CA) or superior mesenteric artery (SMA) stenosis with CA PSV >200 cm/s (median = 222.8 cm/s; range = 201.5-427.1 cm/s) and/or SMA PSV >275 cm/s (median 183.2 cm/s; range = 87.8-289.3 cm/s). Among the six subjects, five had elevated soluble P-selectin values (median 72.55 ng/mL), while all six (100%) had elevated cystatin C levels (median 4.15 mg/L). Peripheral oxygen saturation was suboptimal in five subjects. All subjects had low hemoglobin concentration levels (median 8.5 g/dL) while four had elevated white blood cell count. Although vaso-occlusive crises result from microvessel occlusion, these findings at the macrovascular level suggest that SCD patients may also be vulnerable to mesenteric ischemic injury, especially in the setting of anemic heart failure from hemolysis.

Gastroscopy assisted laser Doppler flowmetry and visible light spectroscopy in patients with chronic mesenteric ischemia

Mucosal pathology due to chronic mesenteric ischemia (CMI) is rarely seen during upper endoscopy. Combining Laser Doppler Flowmetry (LDF) and Visible Light Spectroscopy (VLS) may aid in detection of CMI at an early stage. We aimed to investigate the utility of LDF and VLS in detecting microcirculatory changes in patients with CMI during upper endoscopy. In a single center, prospective study, 104 patients were evaluated for mesenteric ischemia during a 24 months period. Patients with a consensus diagnosis of CMI (n = 40) were examined with LDF and VLS. Thirty-two were successfully treated and had a definitive diagnosis of CMI. Results were compared with controls (n = 38) with normal intestinal circulation evaluated with duplex ultrasonography (DUS). Treatment response was evaluated clinically and with DUS at 1 month and with VLS and LDF at 3 months. A significant reduction in mucosal capillary hemoglobin oxygen saturation (SO₂) was found in CMI patients compared to controls before treatment: mean ± SD: 67 ± 9%, 81 ± 4%, respectively (p < .001). A significant reduction was also seen for the relative hemoglobin (rHb) amount, flow and velocity (p < .001). The sensitivity of SO₂ measured by VLS for diagnosing CMI was 94% and the specificity 72% (cut-off 78%), calculated with ROC curve analysis. A combination of SO₂ and rHb increased the test sensitivity and specificity to 97% and 79%, respectively. Conclusion: CMI patients have significantly reduced microcirculation in the stomach and duodenum compared to controls. The results suggest that VLS should be included when performing an upper endoscopy in patients with suspected CMI.

Acute and Chronic Ischemic Disorders of the Small Bowel

PURPOSE OF REVIEW

Ischemic disorders of the small bowel represent a rare but highly morbid disease process which is often difficult to diagnose and has a complex management course involving multidisciplinary care. Given recent advances in radiologic modalities and surgical/endovascular techniques, this review seeks to provide a disease overview as well as a summary of emerging management strategies.

RECENT FINDINGS

In cases of acute mesenteric ischemia without evidence of frank bowel necrosis, an endovascular-first strategy employing thrombolysis, pharmacomechanical thrombectomy, and/or adjunctive angioplasty/stenting has been shown to have positive outcomes. In cases requiring open laparotomy, retrograde open mesenteric stenting may facilitate less dissection and more straightforward revascularization. While endovascular intervention for chronic mesenteric ischemia was historically limited by high rates of restenosis, use of covered stents in these vascular beds has been shown to have excellent patency rates. Ischemia of the small bowel can be acute or chronic in nature-endovascular treatment modalities have been shown to have excellent results given appropriate patient selection and should be an important tool in the armamentarium of management options for this complex disease process.

Duplex ultrasound in the early diagnosis of acute mesenteric ischemia: a longitudinal cohort multicentric study

OBJECTIVE

Acute mesenteric ischemia (AMI) is a life-threatening condition requiring time-dependent treatment; thus, early recognition may improve outcomes. We hypothesized that clinician-performed mesenteric vessels duplex ultrasound (DUS) could facilitate early identification of patients with AMI in high-risk patients presenting with abdominal pain.

METHODS

This was a single-operator, observational, prospective cohort study. Patients aged at least 65 presenting to Emergency Departments with acute abdominal pain and no clear diagnosis after an initial work-up were enrolled. All patients underwent multidetector computed tomography and these findings provided the reference standard in this study. DUS of the celiac artery and superior mesenteric artery (SMA) were obtained to measure the peak systolic velocity (PSV) and were performed within 24 h of admission. PSVs outside the normal range were considered to indicate AMI.

RESULTS

Of 49 patients identified, 47 were consented to enrollment and diagnostic images were obtained in 45 (96%). Fifteen patients (33%) had AMI (six occlusive, nine nonocclusive disease). Among these, 12 (80%) had abnormal DUS velocities. SMA PSV showed a sensitivity of 78.57% [95% confidence interval (CI): 49.2-95.34], a specificity of 64.52% (95% CI: 45.37-80.77), a positive predictive value of 50% (95% CI: 28.22-71.78), and a negative predictive value of 86.96% (95% CI: 66.41-97.22) for AMI. DUS had a sensitivity of 100%, a specificity of 64%, and a negative predictive value of 100% for occlusive AMI. Assessment of celiac artery PSV did not improve diagnostic performance.

CONCLUSION

In this single-operator pilot study, mesenteric vessel DUS was performed successfully in the Emergency Department, with a high proportion of diagnostic images obtained. A normal SMA PSV was associated with a low risk of occlusive AMI.

Acute and Isolated Dissection of the Superior Mesenteric Artery: Presentation and follow-up with Duplex Ultrasound

Introduction

Isolated dissection of the superior mesenteric artery (SMA) is a rare and often-fatal condition. Currently, only 47 cases of SMA dissection, in the absence of aortic dissection, have been reported in the literature. This report describes a case wherein the use of duplex ultrasound (DU) established the initial diagnosis and was used aggressively in follow-up care.

Case Report

A 51-year-old man presented to the emergency department (ED) complaining of severe abdominal pain. A DU of the mesenteric vessels was normal with the exception of a focal dilatation noted near the origin of the SMA that was later confirmed by computed tomography. Two days after admission, a second DU revealed a further increase in diameter of the proximal SMA and an intimal flap present in this segment. The patient was managed conservatively and discharged. Approximately 1 year later, the patient returned to the ED complaining of nausea and diarrhea for 3 weeks. DU revealed chronic dissection of the SMA as well as a stenosis in the celiac artery and inferior mesenteric artery (IMA). A stent was placed into the origin of the IMA to ensure collateral blood flow and anticoagulant therapy was continued. Before discharge, another DU was performed, which showed a patent IMA and well-perfused proximal SMA. One week later, the patient was asymptomatic and discharged home.

Conclusions

The use of DU provided a prompt and accurate diagnosis for a rare and unsuspected abnormality in the SMA that proved to be very beneficial in follow-up management decisions.

Long-Term Results of Endovascular Treatment of Atherosclerotic Stenoses or Occlusions of the Coeliac and Superior Mesenteric Artery in Patients With Mesenteric Ischaemia

INTRODUCTION

Over the past decade, primary percutaneous mesenteric artery stenting (PMAS) has become an alternative to open revascularisation for treatment of mesenteric ischaemia. Institutes have presented favourable short-term outcomes after PMAS, but there is a lack of data on long-term stent patency.

METHODS

One hundred and forty-one patients treated by PMAS for acute and chronic mesenteric ischaemia over an 8 year period were studied. Anatomical success was assessed by duplex ultrasound and/or CT angiography. A stenosis ≥70% was considered to be a failure.

RESULTS

Eighty-six coeliac arteries (CA) and 99 superior mesenteric arteries (SMA) were treated with PMAS in 141 patients. Nine CAs (10%) and 30 SMAs (30%) were occluded at the time of treatment. Median follow-up was 32 months (IQR 20-46). The overall primary patency rate at 12 and 60 months was 77.0% and 45.0%. The overall primary assisted patency rate was 90.3% and 69.8%. Overall secondary patency was 98.3% and 93.6%.

CONCLUSION

This study shows excellent long-term secondary patencies after PMAS, comparable with published data on long-term patencies after open surgical revascularisation.

Vascular imaging of the mesenteric vasculature

Imaging of the mesenteric vasculature is crucial in diagnosing vascular disease of the gastro-intestinal tract such as acute or chronic mesenteric ischemia caused by arterial stenosis, embolism or thrombosis, mesenteric vein thrombosis and mesenteric aneurysm or dissection. The reference standard for imaging of the mesenteric vasculature is digital subtraction angiography. However, modalities as duplex ultrasonography, computed tomography angiography and magnetic resonance angiography are developing rapidly and may provide accurate imaging non-invasively. This review provides an up-to-date overview of the anatomic resolution, clinical application, emerging techniques and future perspectives of these four radiological modalities for imaging of the mesenteric vasculature.

Chronic Visceral Ischemia: Symptom-Free Survival After Open Surgical Repair

A retrospective review of patients treated with a history of chronic visceral ischemia (CVI) was made to determine primary patency of open surgical repair and estimated symptom-free survival. Patients with CVI between 1990 and 2003 were reviewed. Included were those with chronic symptoms alone (C-CVI) and acute-on-chronic symptoms (A-CVI). Data were obtained from a vascular database. Symptom-free survival and graft patency were estimated by using product limit estimates. Fifty-eight patients (13 men, 45 women; mean age: 63 years) were treated surgically for C-CVI (34 patients) and A-CVI (24 patients). All patients had postprandial abdominal pain and weight loss (mean: 17 kg). One fourth reported food fear. Preoperative imaging demonstrated disease of the superior mesenteric artery (SMA) (100%; 64% occluded), celiac axis (89%; 37% occluded), and inferior mesenteric artery (IMA) (54%; 60% occluded). Multiple vessels were involved in 95% of patients (mean: 2.3 vessels/patient). Operative management included antegrade revascularization of 80 vessels. Combined aortic and/or renal procedures were performed in 7 patients. Patient demographics and visceral disease did not differ for C-CVI and A-CVI; however, perioperative mortality differed significantly (10% for C-CVI vs 54% for A-CVI [p<0.001]). Intestinal gangrene at presentation was associated with perioperative (hazard ratio [HR]: 7.6; 95% CI: 2.7–21.6; p=0.0002) and follow-up death (HR: 7.8; CI 2.8–21.9; p< 0.0001). Follow-up (mean: 34 months) was complete for 54/68 vessels (79%). Estimated primary and primary assisted patency at 5 years were 81% and 89% respectively. Estimated symptom-free survival for hospital survivors was 57% at 70 months. Open antegrade methods of visceral artery repair for CVI were durable and associated with 57% symptom-free survival at 70 months. Patient demographics and distribution of visceral artery anatomy were similar; however, perioperative mortality for C-CVI and A-CVI differed dramatically. Improved outcomes for A-CVI require recognition and treatment of CVI before onset of intestinal gangrene.

Endovascular treatment of occluded and stenotic visceral vessels in patients with chronic mesenteric ischemia

Objective Current evidence in the literature about endovascular treatment (ET) of visceral vessels in patients with chronic mesenterial ischemia (CMI) based on morphological characteristics is limited. The aim of this study was the evaluation of ET in occluded and stenotic visceral vessels. Methods Patients undergoing ET for CMI between November 2000 and November 2012 were included in this retrospective study. Primary measure outcome was the symptom-free survival (SFS). Secondary outcomes were primary (PPR), secondary patency (SPR) rates and technical success rate (TSR). A Cox-regression analysis identified risk factors for the primary and secondary measure outcomes. Results Forty patients were included in the present study (men: 21, mean age: 68). The overall number of vessels with intention-to-treat was 62. Fifty-two visceral arteries (18 occlusions and 34 stenoses) were successfully treated by endovascular means. The overall TSR was 84%. Visceral vessel occlusions and atherosclerotic disease of the superior mesenteric artery (SMA) were identified as independent risk factors for poorer TSR ( p < 0.05). The 12-month SFS was 60%. The overall 12-month PPR and SPR were 71% and 94%, respectively. No significant differences were observed between occluded and stenotic vessels ( p > 0.05) concerning the PPR. On the other hand, the subgroup analysis revealed higher SPR among occluded visceral vessels ( p < 0.001) and coeliac axis lesions ( p < 0.001). Conclusions ET was associated with high incidence of symptoms recurrence despite the satisfying patency rates in both occluded and stenotic vessels. Additionally, visceral vessel occlusion and presence of atherosclerotic lesions in the SMA were associated with poorer TSR.

Radiology and mesenteric ischaemia

This review focuses on the radiology of mesenteric ischaemia. Covering the acute and chronic presentations, both of which result from impaired vascularisation of the gastrointestinal tract, we evaluate the role of radiographs, ultrasound, CT, MRI, and catheter angiography in the diagnosis of these conditions. Looking to the future, we also assess some of the emerging imaging techniques. Across medicine and surgery there has been a significant shift towards minimally invasive interventions. Although percutaneous revascularisation of chronic mesenteric ischaemia has been performed for some time, there has been a developing trend for the use of such techniques in acute mesenteric ischaemia. We evaluate the available evidence for the use of these percutaneous interventions and assess how they compare with or in some instances compliment traditional surgical alternatives.

Technique and outcomes of robot-assisted median arcuate ligament release for celiac artery compression syndrome

OBJECTIVE

Celiac artery compression by the median arcuate ligament (MAL) is a potential cause of postprandial abdominal pain and weight loss that overlaps with other common syndromes. Robotic technology may alter the current paradigm for surgical intervention. Open MAL release is often performed with concurrent bypass for celiac stenosis due to the morbidity of reintervention, whereas the laparoscopic approach is associated with high rates of conversion to open due to bleeding. We hypothesized that a robot-assisted technique might minimize conversion events to open, decrease perioperative morbidity, and defer consideration of vascular bypass at the initial operative setting.

METHODS

We retrospectively analyzed patients treated for MAL syndrome by a multidisciplinary team at a tertiary medical center between September 2012 and December 2013. Diagnosis was based on symptom profile and peak systolic velocity (PSV) >200 cm/s during celiac artery duplex ultrasound imaging. All patients underwent robot-assisted MAL release with simultaneous circumferential neurolysis of the celiac plexus. Postoperative celiac duplex and symptom profiles were reassessed longitudinally to monitor outcomes.

RESULTS

Nine patients (67% women) were evaluated for postprandial pain (100%) and weight loss (100%). All patients had celiac stenosis by mesenteric duplex ultrasound imaging (median PSV, 342; range, 238-637 cm/s), and cross-sectional imaging indicated a fishhook deformity in five (56%). Robot-assisted MAL release was completed successfully in all nine patients (100%) using a standardized surgical technique. Estimated blood loss was <50 mL, with a median hospital stay of 2 days (range, 2-3 days). No postoperative complications of grade ≥3, readmissions or reoperations were observed. All patients (100%) improved symptomatically at the 25-week median follow-up. Three patients experienced complete resolution on postoperative celiac duplex ultrasound imaging, and six patients showed an improved but persistent stenosis (PSV >200 cm/s) compared with preoperative velocities (P < .05 by Wilcoxon signed rank). No patients required additional treatment.

CONCLUSIONS

Robot-assisted MAL release can be performed safely and effectively with avoidance of conversion events and minimal morbidity. Potential factors contributing to success are patient selection by a multidisciplinary team and replication of the open surgical technique by means of robot-assisted dexterity and visualization. The need for delayed reintervention for persistently symptomatic celiac stenosis is uncertain.

Management of Mesenteric Ischemia

Acute mesenteric ischemia is associated with a high mortality rate and requires emergent evaluation and surgical management. However, patients with chronic mesenteric ischemia can undergo either surgical or endovascular revascularization. Review of recent medical literature suggests lower rates of mortality and complications after endovascular revascularization, but higher rates of primary patency after surgical revascularization. The decision regarding method of revascularization in patients with chronic mesenteric ischemia should be based on the patient's vascular anatomy, comorbidities, and life expectancy.

Mesenteric stenosis, collaterals, and compensatory blood flow

BACKGROUND

The mesenteric circulation has an extensive collateral network. Therefore, stenosis in one or more mesenteric arteries does not necessarily lead to symptoms. The objective of this study was to determine the effect of collateral flow on celiac artery (CA) and superior mesenteric artery (SMA) duplex parameters.

METHODS

Between 1999 and 2007, a cohort of 228 patients analyzed for suspected chronic mesenteric syndrome was studied. Stenosis of the mesenteric vessels and collateral flow patterns were identified on angiography and categorized. The effect of stenosis in one mesenteric vessel and the presence of collaterals from the other unaffected vessel was examined in both the CA and SMA.

RESULTS

Stenosis of the CA resulted in a significantly higher peak systolic velocity (PSV) and end-diastolic velocity in the normal SMA without stenosis. This was also found for the CA without stenosis in the presence of a stenosis of the SMA. An incremental effect of the severity of the CA stenosis was found with a mean SMA PSV of 158 cm/s when normal and 259 cm/s when occluded. The presence of collaterals had a clear effect on duplex parameters of the angiographically normal SMA. In the presence of collaterals and a 70% CA stenosis, the PSV in the normal SMA was significantly higher (P = .025).

CONCLUSIONS

This study shows that stenosis in either the CA or SMA increases flow velocities in the other unaffected mesenteric artery. This increase was correlated with the presence of collaterals. Collaterals and stenoses in one of the mesenteric arteries may lead to mimicking or overgrading of stenosis in the other mesenteric artery.

Eight years experience in the management of median arcuate ligament syndrome by decompression, celiac ganglion sympathectomy, and selective revascularization

We aim to review an 8-year experience of median arcuate ligament syndrome (MALS) with chronic gastrointestinal ischemia (CGI) and evaluate clinical outcomes of arcuate ligament decompression, celiac sympathectomy, and selective revascularization. Between December 2002 and March 2012, of 25 patients referred with symptoms of CGI, 11 patients (10 women and 1 man) had clinical signs of abdominal angina and radiological evidence of MALS. Mean age was 50 ± 20.4 years. Median symptom duration was 34 months. All patients had median arcuate decompression and celiac sympathectomy. In all, 8 did not require revascularization, 2 had retrograde celiac and/or superior mesenteric artery (SMA) stenting, and 1 had SMA bypass. There was no mortality. The 30-day morbidity was 9%. Mean follow-up was 60 months. Eight patients noted complete relief of abdominal pain, and 1 reported some improvement. The MALS is not solely a vascular compression syndrome. The neurological component requires careful celiac plexus sympathectomy in addition to arcuate ligament decompression.

Mesenteric ischemia

This article reviews the presentation, diagnosis, evaluation, and treatment of the various forms of mesenteric ischemia, including acute and chronic ischemia. In addition, nonocclusive mesenteric ischemia and median arcuate ligament compressive syndrome are covered. The goals are to provide a structured and evidence-based framework for the evaluation and management of patients with these intestinal ischemia syndromes. Special attention is given to avoiding typical pitfalls in the diagnostic and treatment pathways. Operative techniques are also briefly discussed, including an evidence-based review of newer endovascular techniques.

Subject body mass index affects Doppler waveform in celiac artery by duplex ultrasound

OBJECTIVE

The aim of this study is to evaluate the effect of body mass index (BMI) on peak systolic velocity (PSV) recording in the celiac artery (CA).

SUBJECTS & METHODS

Forty male participants were entered prospectively into the study. The subjects were divided into two groups according to their body mass index. Group A included subjects with BMI ≤25 Kg/m(2) and those in group B with BMI >25 Kg/m(2). The diameter and PSV at the origin of CA of subjects in both groups were recorded while the subject positioned in supine and during expiration phase and fasted for 4 hours using duplex ultrasound. Both groups were matched for age and sex. Independent Student's t-test was used to test if there is any statistical significance between diameter and PSV in both groups.

RESULTS

Group A's, average age (year, ±SD) was 29.35±1.35 and average BMI (Kg/m(2), ±SD) was 23.1±1.60. Group B's, average age was 30±2.1 and their average BMI was 31±5.1. The average diameter (cm, ±SD) of CA in group A was 0.66±0.076 and in group B was 0.80±0.066. However, the average PSV (cm/s, ±SD) was 117±28.1 in group A and 102±12.4 in group B. Independent student t-test showed statistical significance between both groups for the diameter (p=0.005) and just reached statistical significance for PSV (p=0.049).

CONCLUSION

Subjects with higher BMI showed reduced PSV due to a larger CA diameter and probably due to more fatty tissue accumulation around the CA origin.

Ischemic bowel syndromes

Atherosclerotic vascular disease involving the mesenteric arteries occurs frequently in the elderly population. Although the prevalence of ischemic bowel disease is difficult to determine, acute mesenteric ischemia (AMI) has been reported to cause in 1 in 1000 hospital admissions, whereas chronic mesenteric ischemia (CMI) is estimated to affect 1 in 100,000 individuals. Mesenteric ischemia generally manifests in its chronic form as postprandial abdominal pain resulting in significant weight loss, and in its acute form as an abrupt development of abdominal pain, lower gastrointestinal bleeding, and subsequent intestinal necrosis. This article discusses the cause, clinical manifestations, diagnosis, and management of AMI and CMI.