Contemporary management of acute mesenteric ischemia: Factors associated with survival

Isolated bypass to the superior mesenteric artery for chronic mesenteric ischemia

Mesenteric ischemic symptoms appear only when two of the three major splanchnic arteries from the abdominal aorta are involved. Recently, we encountered a case of chronic mesenteric ischemia in a 50-year-old female patient caused by atherosclerotic obstruction of the celiac trunk and superior mesenteric artery. She was treated with a retrograde bypass graft from the right common iliac artery to the superior mesenteric artery (SMA) in a C-loop configuration. Complete revascularization is recommended for treatment of intestinal ischemia. When the celiac trunk is a not suitable recipient vessel, bypass grafting to the SMA alone appears to be both an effective and durable procedure for treating intestinal ischemia.

Treatment outcome in patients with acute superior mesenteric artery embolism

PURPOSE

The goals of this study were to investigate the treatment outcomes of acute mesenteric ischemia caused by superior mesenteric artery (SMA) embolism and identify the posttreatment prognostic factors.

METHODS

The clinical data of 32 episodes of acute SMA embolism in 30 patients, including 2 recurrent cases, between April 2003 and March 2011 were retrospectively reviewed.

RESULTS

Median patient age was 74 years (range, 39-89 years), and 50% were male. Conservative treatment, including bowel rest, nasogastric drainage, intravenous fluid therapy, parenteral nutritional support, and anticoagulation therapy, was undertaken in 5 patients with no clinical evidence of bowel gangrene, including 1 with recurrent ischemia. No deaths occurred among patients treated conservatively. A total of 27 patients were treated with open surgical repair (25 embolectomies and 2 bowel resections alone). Among 25 patients treated with embolectomy, 14 required bowel resection. Most bowel resections (94%, 15/16) were limited, with the remaining length of small bowel greater than 150 cm, which could not cause short bowel syndrome. In-hospital mortality of surgery was 30%. No variables were associated with mortality after surgical intervention, including, age, gender, presence of bowel gangrene, and symptom duration. The overall 1-, 3-, and 5-year survival rates after initial successful treatment were 96%, 73%, and 44%, respectively, regardless of treatment type.

CONCLUSIONS

Prompt diagnosis and treatment before extensive irreversible gangrene is the mainstay in the treatment of SMA embolism. Limited bowel gangrene was not associated with mortality.

Local thrombolytic therapy in acute mesenteric ischemia

BACKGROUND

The aim of the study was to evaluate the local thrombolytic therapy (LTT) in combination with laparoscopy, in management of acute mesenteric ischemia (AMI).

METHODS

From January 2000 to January 2010, patients who were admitted to the hospital with AMI due to acute arterial occlusion were analysed retrospectively. Patients presenting with acute abdomen with a suspicion of AMI were evaluated with computerized tomography angiography (CTA). Patients who had findigs of AMI on CTA, were underwent selective mesenteric angiography and LTT eventhough without peritoneal signs. LTT was carried out before or after laparoscopy or laparotomy, and initiated with recombinant plasminogen activator.

RESULTS

LTT was performed in 13 (17.1%), out of 76 patients. From the remaining patients, 56 underwent necrotic bowel resection and 7 underwent tromboembolectomy. The median age was 62 years (45-87). The median duration of symptoms was 24 h. Four (30.7%) patients presented within 24 h onset of symptoms, whilst 9 (69.3%) patients presented after 24 h onset of symptoms. There were 5 (39.5%) patients, who presented with abdominal pain without peritoneal signs on physical examination and 8 (61.5%) patients, who had peritoneal signs. The mortality rate was 20% (1/5) in the first group who presented without peritoneal signs, whilst it was 62.5% (5/8) in the remaining.

CONCLUSION

Early intervention in AMI is the key to better results. CTA combined with early laparoscopy and LTT may have beneficial effects at this setting.

Effects of a multimodal management strategy for acute mesenteric ischemia on survival and intestinal failure

BACKGROUND & AIMS

Acute mesenteric ischemia (AMI) is an emergency with a high mortality rate; survivors have high rates of intestinal failure. We performed a prospective study to assess a multidisciplinary and multimodal management approach, focused on intestinal viability.

METHODS

In an Intestinal Stroke Center, we developed a multimodal management strategy involving gastroenterologists, vascular and abdominal surgeons, radiologists, and intensive care specialists; it was tested in a pilot study on 18 consecutive patients with occlusive AMI, admitted to a tertiary center from July 2009 to November 2011. Patients with left ischemic colitis, nonocclusive AMI, chronic mesenteric ischemia, and other emergencies were excluded. Patients received specific medical management: revascularization of viable small bowel and/or resection of nonviable small bowel; 12 patients received arterial revascularization. We evaluated the percentages of patients who survived for 30 days or 2 years, the number with permanent intestinal failure, and morbidity. Lengths and rates of intestinal resection were compared with or without revascularization, and in patients with early or late-stage disease.

RESULTS

Patients were followed up for a mean of 497 days (range, 7-2085 d); 95% survived for 30 days, 89% survived for 2 years, and 28% had morbidities within 30 days. Intestinal resection was necessary for 7 cases (39%), with mean lengths of intestinal resection of 30 cm and 207 cm, with or without revascularization, respectively (P = .03). Among patients with early or late-stage AMI, rates of resection were 18% and 71%, respectively (P = .049). Patients with early stage disease had shorter lengths of intestinal resection than those with late-stage disease (7 vs 94 cm; P = .02), and spent less time in intensive care (2.5 vs 49.8; P = .02).

CONCLUSIONS

A multidisciplinary and multimodal management approach might increase survival of patients with AMI and prevent intestinal failure.

Risk factors effecting mortality in acute mesenteric ischemia and mortality rates: a single center experience

The objective of this study is to discuss the effective factors on morbidity and mortality in patients who were operated on for acute mesenteric ischemia. Between 2006 and 2011, 95 patients, who underwent emergent surgery for acute mesenteric ischemia, were analyzed retrospectively. The study group consisted of 56 men (58.9%) and 39 women (41.1%), with an average age of 68.4 ± 14.4 years. Elapsed time between the onset of the symptoms and the surgical operation was less than 24 hours in 47 (49.5%) cases, and more than 24 hours in 48 cases (50.5%) (P < 0.001). Although all of the patients had intestinal necroses, colon involvement was seen in 38 patients, and mortality was higher in this group of patients (P < 0.001). Mortality rate was 42.1%. This was higher in older patients, those with increased leukocyte levels, increased elapsed time to laparotomy, and when the colon was involved.

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.

A study on 107 patients with acute mesenteric ischemia over 30 years

Acute mesenteric ischemia (AMI) is a life threatening cause of acute abdomen. The purpose of this study is to define risk factors that predict the adverse outcome of AMI and to present our experience in the last 30 years. Hospital records and clinical data of 107 patients undergoing surgical intervention for AMI during the last 30 year period were reviewed and clinical outcomes as well as factors influencing mortality were analyzed. Mesenteric arterial thrombosis, arterial embolism and nonocclusive mesenteric ischemia (NOMI) were the cause of AMI in 68 (63.6%), 28 (26%), and 11 patients (10.2%), respectively. Abdominal pain was the most common presenting symptom (90.6%). Peritonitis was observed in 96 patients (89.7%) and 24 patients (22.4%) were in shock. Abdominal ultrasonography was performed in 46 patients (42%), abdominal CT angiography in 36 patients (33%) and mesenteric angiography in 12 patients (10.5%). All patients were operated and 11 (10%) patients underwent a second-look operation. Bowel resection was necessary in 101 patients (93.4%) during the initial operation and in seven patients (6.5%) during the second-look operation. The hospital mortality was 55.1%. Mortality was mainly due to multiorgan failure (43%). Diabetes mellitus, use of digoxine and antiplatelet drugs, duration of the symptoms until before surgery, existence of shock, low levels of the pH and bicarbonate and re-laparotomy were found to be negative predictors of the perioperative mortality. The use of total parenteral nutrition and CT angiography was found to be a protective factor against mortality. A high index of suspicion with prompt diagnostic evaluation with CT angiography may reduce time prior to surgical intervention which may lead to improved patient survival.

Preservation of small bowel with the selective use of heparin and second look laparotomy in acute mesenteric ischaemia: A case report

INTRODUCTION

Acute mesenteric ischaemia may occur due to mesenteric arterial embolus, thrombosis, non-occlusive mesenteric ischaemia or venous thrombosis resulting in ischaemia of the bowel wall.

PRESENTATION OF CASE

A 41year old woman presented with worsening abdominal pain, decreased appetite, nausea and vomiting. Examination revealed right lower quadrant tenderness. Investigations revealed elevation of her inflammatory markers. At laparotomy two separate segments of ischaemic but potentially viable small bowel were identified secondary to mesenteric venous thrombosis. Bowel salvage was attempted with the use of intravenous unfractionated heparin and this was confirmed following a second look laparotomy.

DISCUSSION

Despite a normal platelet count at presentation a diagnosis of JAK-2 positive essential thrombocythaemia was made thus explaining the acquired prothrombotic state underlying the venous thrombosis. The selective use of intravenous unfractionated heparin and second look laparotomy may provide a means for bowel preservation in these cases.

CONCLUSION

This case highlights the potential of bowel salvage can be achieved following an episode of acute mesenteric ischaemia with the use of intravenous unfractionated heparin and selective second look laparotomy and the importance of considering underlying myeloproliferative disease in such cases even in the absence of a thrombocytosis at presentation.

Revascularization for acute mesenteric ischemia

OBJECTIVE

Acute mesenteric ischemia (AMI) remains difficult to diagnose, carries a high rate of complications, and is associated with significant mortality. We evaluated our experience with AMI over the last 2 decades to evaluate changes in management and assess current outcomes.

METHODS

Data from consecutive patients who underwent arterial revascularization for AMI over a 20-year period (January 1990-January 2010) were retrospectively reviewed. Patient demographics, treatment modalities, and outcomes over the last decade (2000-2010) were compared with those of the preceding decade (1990-1999) previously reported.

RESULTS

Over the last 2 decades, 93 patients with AMI underwent emergency arterial revascularization. Forty-five patients were treated during the 1990s and 48 during the 2000s. The majority of these patients were transferred from outside facilities. Patient demographics and risk factors were similar between the 2 decades with the exception that the more contemporary patients were significantly older (65.1 ± 14 vs 71.3 ± 14; P = .04). Etiology remained constant between the groups with in situ thrombosis being the most common followed by arterial embolus. The majority of patients were treated with open revascularization. Endovascular therapy alone or as a hybrid procedure was used in 11 total patients, eight of which were treated in the last 10 years. The use of second-look laparotomy was much more liberal in the last decade (80% vs 48%; P = .003) Thirty-day mortality was 27% in the 1990s and 17% during the 2000s (P = 0.28). Major adverse events occurred in 47% of patients with no difference between decades. There was no significant difference in outcomes between open and endovascular revascularization. On univariate analysis, elevated SVS comorbidity score, congestive heart failure, and chronic kidney disease predicted early death, while a history of chronic mesenteric ischemia appeared protective. On multivariate analysis, no factor independently predicted perioperative mortality. Bowel resection and cerebrovascular disease predicted postoperative morbidity, while advanced age and connective tissue disease predicted long-term mortality.

CONCLUSIONS

Morbidity and mortality from AMI continues to be high. Revascularization by endovascular means, although more frequent in the last decade, was still utilized in a minority of patients with severe AMI. Advanced ischemia with bowel infarction at presentation, and markers of generalized atherosclerosis are predictors of poor outcome, while history of chronic mesenteric ischemia is associated with better outcome.

Acute superior mesenteric artery embolism: reperfusion with AngioJet hydrodynamic suction thrombectomy and pharmacologic thrombolysis with the EKOS catheter

Acute mesenteric ischemia is commonly treated by surgical exploration and open thrombectomy. Very few reports describe using newer, minimally invasive methods which utilize catheter-based mechanical and pharmacological thrombolysis. Herein, we report a case of acute superior mesenteric embolism successfully treated with AngioJet hydrodynamic mechanical thrombectomy and EKOS catheter pharmacological thrombolysis. A 76-year-old man with new onset atrial fibrillation presented with abdominal pain of 48 hours duration. Subsequent contrast computed tomography scan of the abdomen revealed a filling defect in the superior mesenteric artery (SMA), suggestive of an acute embolus, which was confirmed by SMA angiogram. The AngioJet aspiration device was used for hydrodynamic suction thrombectomy. The repeat angiogram demonstrated only a partial restoration of blood flow, and thus the EKOS tissue plasminogen activator catheter was left in the SMA for continuous thrombolysis. The patient underwent continuous thrombolysis for two days, with two subsequent sessions of angiography. Thereafter, the patient improved symptomatically and serum lactate was normalized. In conclusion, the AngioJet suction thrombectomy and pharmaco-mechanical thrombolysis using the EKOS catheter is associated with minimal morbidity and can be rapidly performed. It may be used as an alternative to open surgical thrombectomy in selected cases of acute SMA embolism.

Acute mesenteric ischaemia and unexpected death

Acute mesenteric ischaemia is a vascular emergency that arises when blood flow to the intestine is compromised leading to tissue necrosis. It is primarily a condition of the elderly associated with significant morbidity and mortality. Causes include arterial thromboembolism, venous thrombosis and splanchnic vasoconstriction (so-called nonocclusive mesenteric ischaemia). Reperfusion injury and breakdown of the intestinal mucosal barrier lead to metabolic derangements, sepsis and death from multiorgan failure. The diagnosis may be difficult to make clinically and numbers of cases are increasing due to ageing of the population. The clinical and pathological features are reviewed with discussion of predisposing conditions. Careful dissection of the mesenteric vasculature is required at autopsy with appropriate histologic sampling and documentation of associated comorbidities. Other organs need to be checked for thrombi and the possibility of testing for inherited thombophilias should be considered. Toxicological evaluation, particularly in younger individuals, may reveal evidence of cocaine use. On occasion no obstructive lesions will be demonstrated, however the confounding effects of post-mortem autolytic and putrefactive changes may mean that nonocclusive mesenteric ischaemia may be difficult to diagnose.

Open versus closed abdomen treatment on liver function in rats with sepsis and abdominal compartment syndrome

BACKGROUND

Despite recent advances in understanding the mechanisms of sepsis and abdominal compartment syndrome (ACS) and of improvements in their management, the mortality rates from these conditions remain high. Few studies have compared liver injuries in patients undergoing open and closed abdomen treatment. The aim of this study was to compare the effects of open versus conservative abdominal closure approaches upon liver function using a controlled and randomized model of intra-abdominal hypertension and sepsis in a rat model.

METHODS

Healthy Sprague-Dawley rats underwent cecal ligation and puncture to induce sepsis, followed by intraperitoneal injection of air to induce intra-abdominal hypertension. Twenty-four hours later, the rats were randomly divided into two groups, one (n = 36) undergoing abdominal closure and the other (n = 36) undergoing open abdomen. Rats were killed after 1 hour, 6 hours, 1 day, 3 days, 5 days, and 7 days. Liver injury was evaluated by Hepatic Injury Severity Scoring. The levels of expression of Toll-like receptor 4 (TLR4), tumor necrosis factor-α, interleukin-6, signaling transducer and activator of transcription 3 mRNA, and suppressor of cytokine signaling 3 mRNA were assayed by reverse transcription-polymerase chain reaction.

RESULTS

The levels of tumor necrosis factor-α, interleukin-6, and signaling transducer and activator of transcription 3 mRNA were higher, and those of TLR4 and suppressor of cytokine signaling 3 mRNA were lower, in the open than in the closed group (p < 0.05 each). Serum concentrations of aspartate aminotransferase and alanine aminotransferase were also lower in the open group (p < 0.05 each).

CONCLUSIONS

Open abdominal management may improve liver regeneration soon after surgery, as well as reducing inflammatory responses, by reducing TLR4 expression.

Morbidity and mortality after bowel resection for acute mesenteric ischemia

BACKGROUND

Patients presenting with acute mesenteric ischemia (AMI) sufficiently advanced to require bowel resection have a high morbidity and mortality. The objective of this study was to analyze these patients to determine if certain pre- or intraoperative variables are predictive of death or complications which could then be used to develop a predictive model to aid in surgical decision-making.

METHODS

Patients undergoing bowel resection for AMI were identified from the American College of Surgeons' National Surgical Quality Improvement Program database (2007-2008). Multiple logistic regression analysis was performed.

RESULTS

The 861 patients identified had a median age of 69 years. Thirty-day postoperative morbidity and mortality were 56.6% and 27.9%, respectively. Pre- and intraoperative variables significantly associated with postoperative mortality (C statistic, 0.84) included preoperative do not resuscitate order, open wound, low albumin, dirty vs clean-contaminated case, and poor functional status. Pre- and intraoperative variables significantly associated with postoperative morbidity (C statistic, 0.79) included admission from chronic care facility, recent myocardial infarction, chronic obstructive pulmonary disease, requiring ventilator support, preoperative renal failure, previous cardiac surgery, and prolonged operative time. A predictive risk calculator was developed using these variables.

CONCLUSION

Mortality and morbidity rates after bowel resection for AMI are high. A risk calculator for prediction of postoperative mortality and morbidity has been developed and awaits validation in subsequent studies.

Quality improvement guidelines for percutaneous catheter-directed intra-arterial thrombolysis and mechanical thrombectomy for acute lower-limb ischemia

Percutaneous catheter-directed intra-arterial thrombolysis is a safe and effective method of treating acute and subacute lower limb ischemia, as long as accurate patient selection and procedural monitoring are ensured. Although larger, controlled trials are needed to establish the role of PTDs in ALI, mechanical thrombectomy could currently be applied combined with lytic infusion in selected cases where rapid recanalization is required or as a stand-alone therapy when the administration of thrombolytic agents is contraindicated.

Outcomes of revascularized acute mesenteric ischemia in the American College of Surgeons National Surgical Quality Improvement Program database

This report examines outcomes of revascularization for acute arterial mesenteric ischemia (AAMI) using the American College of Surgeons National Surgical Quality Improvement Program database. Patients with International Classification of Diseases, 9th Revision and Current Procedural Terminology codes indicating AAMI with concomitant mesenteric revascularization were identified. Demographic, risk factor, procedural, morbidity, and mortality data were examined. Associations with morbidity and mortality were analyzed by logistic regression. One hundred forty-two cases of AAMI were identified. Seventy-one cases were thrombotic and 71 were embolic according to revascularization codes. Mean age was 66 years, 84 per cent of patients were white, and 54 per cent were female. Unadjusted major morbidity and mortality rates were 69 and 30 per cent, respectively. Patients with thrombotic AAMI were more likely to have a lower body mass index, greater than 10 per cent weight loss in the past 6 months, and a history of smoking. Patients with embolic AAMI were more likely to present emergently with sepsis. Unadjusted morbidity and mortality rates were 78 and 38 per cent for embolic and 61 and 23 per cent for thrombotic AAMI, respectively. Multivariable predictors of morbidity included bowel resection at the time of revascularization, transfer admission, and involvement of a surgical resident. Multivariable predictors of mortality included impaired functional status, increased age, and postoperative sepsis. Cause of AAMI was not a significant predictor of morbidity or mortality. In a large sample of AAMI cases, AAMI remained a highly lethal and morbid condition. Predictors of morbidity and mortality included indicators of advanced presentation, treatment delay, and patient-related factors specific to AAMI, including debility and advanced age. Efforts directed at prevention and increasing the speed of diagnosis and definitive treatment appear to be necessary to improve outcomes.

Clinical value of comprehensive intervention in the management of superior mesenteric artery embolism caused by atrial fibrillation

AIM: To evaluate the clinical value of comprehensive intervention in the management of superior mesenteric artery embolism caused by atrial fibrillation.

METHODS: The clinical data for four patients who had superior mesenteric artery embolism caused by atrial fibrillation and underwent comprehensive intervention at our hospital from 2008 to 2011 were analyzed retrospectively. The comprehensive intervention consisted of transcatheter arterial fibrinolysis/infusion (TAF/TAI), suction embolectomy, percutaneous transluminal angioplasty (PTA) and anticoagulation.

RESULTS: Treatment duration ranged from 6 to 29 hours. Vascular recanalization was achieved in three patients, of whom one died of recurrence. The embolus was moved to the distal branches in one patient. No patients received surgical operation, and no treatment-related complications occurred.

CONCLUSION: Comprehensive intervention is safe and effective in managing superior mesenteric artery embolism caused by atrial fibrillation.

Role of multidetector CT angiography in the evaluation of suspected mesenteric ischemia

OBJECTIVE

To assess the role of multidetector CT angiography (MDCTA) in the diagnosis of acute mesenteric ischemia (AMI) and to compare the diagnostic utility of axial images with reconstructed images.

MATERIALS AND METHODS

In this Institute Review Board approved prospective study, MDCTA was performed on 31 patients who presented with the clinical suspicion of AMI (25M; 6F, age range: 16-73 years). Axial and reconstructed images of each patient were evaluated independently by two radiologists for evidence of bowel wall thickening, abnormal mucosal enhancement, bowel dilatation or obstruction, mesenteric stranding, ascites, solid organ infarcts, pneumatosis intestinalis or porto-mesenteric gas, and mesenteric arterial or venous occlusion. MDCT findings were correlated with the surgical findings and clinical outcome. Patients were later divided into two groups: a study group of patients with proven AMI and a control group of patients with an alternate diagnosis, for the purpose of statistical analysis.

RESULTS

AMI was correctly diagnosed in all 16 patients on MDCTA (100% sensitivity and specificity) of whom nine patients underwent surgical exploration. Three patients expired before surgery and the remaining 5 patients were proven based on positive clinical and laboratory findings. Mesenteric arterial occlusion was seen in 7 patients while 5 patients had portomesenteric venous thrombosis. Reconstructed images using minimum intensity projection, volume rendering and multiplanar volume reconstruction were found to perform better for the detection of vascular abnormalities and improved the diagnostic confidence of both radiologists in the evaluation of bowel and mesenteric abnormalities.

CONCLUSION

MDCTA is an effective non-invasive modality for the diagnosis of mesenteric ischemia.

Acute mesenteric ischemia

OPINION STATEMENT

Acute mesenteric ischemia is caused by a critical reduction in intestinal blood flow that frequently results in bowel necrosis and is associated with a high mortality. Clinicians must maintain a high index of suspicion because a prompt diagnosis and early aggressive treatment before the onset of bowel infarction results in reduced mortality. Medical management includes aggressive rehydration and the use of antibiotics, anticoagulation, vasodilators, and inhibitors of reperfusion injury. If acute mesenteric ischemia is suspected, early angiography is imperative, as it permits accurate diagnosis and possible therapeutic intervention. Therapeutic options during angiography depend on the cause of ischemia and include administering intra-arterial vasodilators and/or thrombolytic agents and angioplasty with or without stent placement. If interventional techniques are not possible or if the patient presents with suspicion of bowel infarction, surgery is warranted. Surgical techniques include superior mesenteric artery embolectomy or visceral artery bypass, which should be used before bowel resection to ensure only resection of nonviable bowel.

Analysis of exhaled volatile compounds following acute superior mesenteric artery occlusion in a pilot rat study

BACKGROUND

Prompt diagnosis and treatment of acute mesenteric ischemia (AMI) requires a high index of suspicion for timely management. Poor clinical outcomes and delays in surgical treatment are demonstrated even in modern clinical series. Recognition of exhaled volatile organic compounds (VOCs) specific to AMI may facilitate early detection and diagnosis and improve patient outcomes.

METHODS

Adult Wistar rats (n = 5) were intubated and anesthetized, and control tracheostomy breath samples were collected using Tedlar gas sample bags. Intestinal ischemia was induced by placing an occlusive clip across the superior mesenteric artery, and breath samples were collected after 1 hour of intestinal ischemia and after 15 minutes of intestinal reperfusion. Gas chromatography was used to identify and measure levels of VOCs obtained, and measured retention indices were compared with known values in the Kovats retention index database.

RESULTS

Multiple retention indices (n = 41) were noted on gas chromatography, representing a variety of VOCs detected. Z,Z-farnesol (C15H26O), an isoprenoid, was the only compound detected that was undetectable during the control phase (median = 0 cts/sec) but which significantly elevated during the ischemic (median = 34 cts/sec, range = 25-37) and reperfusion (median = 148 cts/sec, range = 42-246) phases. Three other isoprenoid compounds (E,E-alpha-farnesene, germacrene A, and Z,Z-4,6,8-megastigmatriene) were also detected in all five animals, but their levels did not differ significantly between control, ischemic, and reperfusion phases.

CONCLUSIONS

This pilot study demonstrates the feasibility of analyzing exhaled VOCs using a novel rat model for AMI. These findings may be useful for the development and identification of similar assays for the rapid diagnosis of AMI.

Acute thrombotic mesenteric ischemia: primary endovascular treatment in eight patients

INTRODUCTION

The purpose of this study was to evaluate our experience with initial percutaneous transluminal angioplasty (PTA) ± stenting as valuable options in the acute setting.

METHODS

Between 2003 and 2008, eight patients with abdominal angio-MDCT-scan proven thrombotic AMI benefited from initial PTA ± stenting. We retrospectively assessed clinical and radiological findings and their management. Seven patients presented thrombosis of the superior mesenteric artery, and in one patient both mesenteric arteries were occluded. All patients underwent initial PTA and stenting, except one who had balloon PTA alone. One patient was treated by additional in situ thrombolysis.

RESULTS

Technical success was obtained in all patients. Three patients required subsequent surgery (37.5%), two of whom had severe radiological findings (pneumatosis intestinalis and/or portal venous gas). Two patients (25%) died: both had NIDD, an ASA score ≥4, and severe radiologic findings. Satisfactory arterial patency was observed after a follow-up of 15 (range, 11-17) months in five patients who did not require subsequent surgery, four of whom had abdominal guarding but no severe CT scan findings. One patient had an ileocecal stenosis 60 days after the procedure.

CONCLUSIONS

Initial PTA ± stenting is a valuable alternative to surgery for patients with thrombotic AMI even for those with clinical peritoneal irritation signs and/or severe radiologic findings. Early surgery is indicated if clinical condition does not improve after PTA. The decision of a subsequent surgery must be lead by early clinical status reevaluation. In case of underlying atherosclerotic lesion, stenting should be performed after initial balloon dilatation.

Acute abdominal pain in the older adult

Abdominal pain in older adults is a concerning symptom common to a variety of diagnoses with high morbidity and mortality. Organizing the differential into categories based on pathology (inflammatory, obstructive, vascular, or other causes) provides a framework for the history, physical, and diagnostic studies. An organized approach and treatment and considerations specific to the geriatric population are discussed.

[Diagnosis and management of acute mesenteric ischemia]

The prevalence of significant splanchnic arterial stenoses is increasing, but remains mostly asymptomatic due to abundant collateral circulation. Acute insufficiency of mesenteric arterial blood flow accounts for 60 to 70% of cases of mesenteric ischemia and results mostly from a superior mesenteric embolus. Despite major advances have been achieved in understanding the pathogenic mechanisms of bowel ischemia, its prognosis remains dismal with mortality rates about 60%. The diagnosis of acute mesenteric ischemia depends upon a high clinical suspicion, especially in patients with known risk factors. Rapid diagnosis is essential to prevent intestinal infarction. However, early signs and symptoms of mesenteric ischemia are non specific, and definitive diagnosis often requires radiologic examinations. Early and liberal implementation of angiography has been the major advance over the past 30 years which allowed increasing diagnostic accuracy of acute mesenteric ischemia. CT and MR-based angiographic techniques have emerged as alternatives less invasive and more accurate to analyse splanchnic vessels and evaluate bowel infarction. The goal of treatment of patients with acute mesenteric ischemia is to restore intestinal oxygenation as quickly as possible after initial management that includes rapid hemodynamic monitoring and support. Surgery should not be delayed in patients suspected of having intestinal necrosis.

Risk factors for intestinal ischaemia among patients registered in a UK primary care database: a nested case-control study

BACKGROUND

Intestinal ischaemia, including ischaemic colitis and acute mesenteric ischaemia, causes significant morbidity and mortality. Few population-based studies have estimated incidence and potential risk factors for this disease.

AIMS

To estimate the incidence of intestinal ischaemia and identify the associated risk factors in cohorts: (i) patients with irritable bowel syndrome and/or chronic constipation (IBS/CC/both), (ii) individuals free of these conditions.

METHODS

Population-based case-control analysis nested in a cohort of patients with first ever recorded diagnosis of IBS/CC/both and a cohort free of these conditions from general population using the General Practice Research Database.

RESULTS

Of 78 cases of intestinal ischaemia, 71 were from general population, seven from the IBS/CC/both cohort. Incidence rate of intestinal ischaemia in IBS/CC/both patients vs. general population was 4.49:1.09 per 100,000 person-years; age- and gender-adjusted incidence rate ratio (95% CI) was 2.7 (1.2-5.9). Inflammatory bowel disease and heart failure showed an association with ischaemic colitis [OR (95% CI): 4.2 (0.5-38.4) and 5.6 (2.2-14.1)], but none with acute mesenteric ischaemia. Diabetes and prior cardiovascular surgery were associated with higher risk of acute mesenteric ischaemia, but showed no association with ischaemic colitis.

CONCLUSIONS

Results suggest that different risk factors are associated with acute mesenteric ischaemia and ischaemic colitis. However, due to small number of patients, associations should be carefully interpreted.

Intestinal ischemia: current treatment concepts

PURPOSE

Mesenteric ischemia is a condition well-known among physicians treating patients with abdominal symptoms. Even so, mortality rates have not decreased significantly over the last decades. The purpose of this article is to review current treatment concepts of acute and chronic mesenteric ischemia.

RESULTS

Early diagnosis is one of the most important features that determine a patient's prognosis. Conventional angiography and multidetector computed tomography are therefore appropriate to quickly diagnose mesenteric ischemia, the latter being commonly more available. Once a patient presents with signs of peritonitis, instant laparotomy is indicated, and infarcted bowel segments need to be resected, followed by a second-look operation if necessary. If bowel necrosis is clinically not suspected, different approaches should be applied according to source and nature of mesenteric ischemia. Besides established surgical treatment concepts, more and more interventional procedures are developed and evaluated. However, superiority of these new techniques could only be shown for selected patient groups so far. In chronic mesenteric ischemia, interventional approaches seem to be an attractive alternative in patients who are in a condition too bad to undergo surgery. Patients with colonic ischemia are treated best in a conservative manner and by resolving the underlying cause, if identified.

CONCLUSION

Patients with acute mesenteric ischemia are still at highest risk for a fatal course of disease. New diagnostic and therapeutic developments have not been tested in larger studies yet, neither has any of these methods led to an increased survival in studies published so far. Taken together, mesenteric ischemia requires high awareness, earliest possible diagnosis, and treatment by an experienced interdisciplinary team of gastroenterologists, radiologists, and surgeons.

Endovascular and open surgery for acute occlusion of the superior mesenteric artery

BACKGROUND

Acute thromboembolic occlusion of the superior mesenteric artery (SMA) is associated with high mortality. Recent advances in diagnostics and surgical techniques may affect outcome.

METHODS

Through the Swedish Vascular Registry (Swedvasc), 121 open and 42 endovascular revascularizations of the SMA at 28 hospitals during 1999 to 2006 were identified. Patient medical records were retrieved, and survival was analyzed with multivariate Cox-regression analysis.

RESULTS

The number of revascularizations of the SMA increased over time with 41 operations in 2006, compared to 10 in 1999. Endovascular approach increased sixfold by 2006 as compared to 1999. The endovascular group had thrombotic occlusion (P < .001) and history of abdominal angina (P = .042) more often, the open group had atrial fibrillation more frequently (P = .031). All the patients in the endovascular group, but only 34% after open surgery, underwent completion control of the vascular reconstruction (P < .001). Bowel resection (P < .001) and short bowel syndrome (SBS; P = .009) occurred more frequently in the open group. SBS (hazard ratio [HR], 2.6; 95% confidence interval [CI], 1.3-5.0) and age (HR, 1.03/year; 95% CI, 1.00-1.06) were independently associated with increased long-term mortality. Thirty-day and 1-year mortality rates were 42% vs 28% (P = .03) and 58% vs 39% (P = .02), for open and endovascular surgery, respectively. Long-term survival after endovascular treatment was better than after open surgery (log-rank, P = .02).

CONCLUSION

The results after endovascular and open surgical revascularization of acute SMA occlusion were favorable, in particular among the endovascularly treated patients. Group differences need to be confirmed in a randomized trial.

Open surgical treatment for chronic mesenteric ischemia in the endovascular era: when it is necessary and what is the preferred technique?

Treatment of chronic mesenteric ischemia has evolved during the last 2 decades. Endovascular treatment has first emerged as an alternative to bypass in the elderly or higher-risk patient, but has become the primary modality of treatment in most patients with suitable lesions, independent of their surgical risk. Open mesenteric revascularization with bypass or (rarely) endarterectomy still has an important role in the treatment of patients with more extensive disease, including long-segment or flush occlusions, small vessel size, multiple tandem lesions, and severe calcification. Our preference for open reconstruction in good-risk patients with multivessel disease is a supraceliac aorta to celiac and superior mesenteric artery (SMA) bypass, whereas an iliac artery to SMA bypass or, occasionally, an infrarenal aortic to SMA bypass is used in the higher-risk group. In this article, we summarize the selection criteria, techniques, and outcomes of open mesenteric reconstruction in the endovascular era.

Acute mesenteric ischemia: diagnostic approach and surgical treatment

Mortality related to acute mesenteric arterial occlusion remains very high. Patient survival is dependent on prompt recognition and revascularization before ischemia progresses to intestinal gangrene. Biphasic computed tomography angiography has surpassed angiography as the diagnostic test of choice due to its ability to define the arterial anatomy and to evaluate secondary signs of mesenteric ischemia. Unlike chronic mesenteric ischemia, the treatment of acute arterial mesenteric ischemia, either embolic or thrombotic, remains largely surgical. This is due to the emergent need for revascularization combined with a careful evaluation of the intestines. Endovascular techniques remain useful, however, and can save precious time in the treatment of these challenging patients if integrated into a treatment pathway combined with definitive surgical treatment. A new hybrid endovascular-surgical treatment for the treatment of acute mesenteric thrombosis is described.

Epidemiology of mesenteric vascular disease: clinical implications

The overall incidence rate of acute mesenteric ischemia between 1970 and 1982, diagnosed at either autopsy or operation, in the population of Malmö, Sweden was estimated at 12.9/100,000 person-years. Autopsy rate was 87%. Acute superior mesenteric artery (SMA) occlusion (embolus/thrombus ratio = 1.4), mesenteric venous thrombosis (MVT), and nonocclusive mesenteric ischemia (NOMI) were found in approximately 68%, 16%, and 16%, respectively. Acute SMA occlusion was found to be more common than ruptured abdominal aortic aneurysms. The incidence increased exponentially with age, equally distributed among men and women after adjusting for age and gender in the population. Thrombotic occlusions were located more proximally than embolic occlusions and intestinal infarction was more extensive, whereas patients with embolus had a higher frequency of acute myocardial infarction, and had cardiac thrombi in 48% and synchronous emboli in 68% of the patients. The proportion of patients with symptoms inherent with chronic mesenteric ischemia prior to onset of acute thrombotic occlusion has been reported to occur in 73%. Cardiac failure, history of atrial fibrillation, and recent surgery have all been associated with fatal NOMI. MVT is either caused by thrombophilia, direct injury, or local venous congestion or stasis. Multidetector row computed tomography with intravenous contrast enhancement and imaging in the arterial phase for suspicion of acute SMA occlusion and imaging in the venous phase for MVT has become the diagnostic method of choice. In-hospital mortality is highest for NOMI, lower for acute SMA occlusion, and lowest, around 20%, for MVT.

Retrograde Open Mesenteric Stenting for Acute Mesenteric Ischemia is a Viable Alternative for Emergent Revascularization

Objectives: Significant comorbidities and an exhausted physiologic reserve lead to high mortality rates during operations for acute mesenteric ischemia. We present our experience with retrograde open mesenteric stenting. Methods/Results: A total of 3 female patients (mean age = 74.1 years) with acute mesenteric ischemia underwent exploratory laparotomy. Operative technique included isolating the superior mesenteric artery for cannulation and retrograde endovascular angioplasty and stenting. One required small bowel resection. All 3 patients survived. Mean follow-up was 8.4 months (range: 1.2-16.6). All remain with a 100% primary patency rate. Conclusion: Retrograde open mesenteric stenting for acute mesenteric ischemia is a viable alternative to bypass.

Epidemiology and prognostic factors in acute superior mesenteric artery occlusion

BACKGROUND

Reports on trends in incidence and mortality of acute superior mesenteric artery (SMA) occlusion and evaluation of prognostic factors in recent years are lacking.

METHODS

Patients with acute SMA occlusion were identified through the in-patient and autopsy registry between 1970 and 1982 (n = 270), 1987 to 1996 (n = 135), and 2000 and 2006 (n = 100) in Malmö, Sweden.

RESULTS

The overall incidence rate decreased from 8.6 to 5.4/100,000 person years and the autopsy rate from 87% to 25% over time. A higher serum creatinine level was associated with a lower probability of undergoing multi-detector row computed tomography with intravenous contrast (MDCTiv) (p = 0.006). Not performing a MDCTiv (odds ratio 4.0; 95% confidence interval [1.0-16.0]) remained as independent prognostic factor for in-hospital mortality. General and vascular surgeons collaborated in 25 out of 61 patients that underwent an intervention, of which 21 (84%) (p < 0.001) survived.

CONCLUSIONS

A close collaboration between radiologists and general and vascular surgeons seems to be most important to lower the mortality in patients with acute SMA occlusion.

Interventions for mesenteric vasculitis

OBJECTIVE

This study reviewed the outcomes of open and endovascular revascularization for mesenteric vasculitis (MV).

METHODS

We reviewed the clinical data of all patients who underwent revascularization for occlusive MV from 1984 to 2008. Patients treated for aneurysms or mucosal bleeding without ischemic symptoms were excluded. End points were early mortality and morbidity, survival, freedom from mesenteric symptoms, and patency. Outcomes of open reconstructions were compared with the results of 163 patients who underwent open operations for atherosclerotic disease.

RESULTS

There were 15 patients (13 females, 2 males) with a mean age of 38 years (range, 15-66 years). Etiologies were Takayasu's arteritis in 7, polyarteritis nodosa in 4, indeterminate in 3, and giant cell arteritis in 1. The celiac axis was affected in 13, superior mesenteric artery (SMA) in 13, renal arteries in 8, and the aorta in 4. Seven patients had active disease, and eight were in remission. Nine (60%) presented with symptomatic chronic (n = 8) and acute (n = 1) mesenteric ischemia. Six patients with asymptomatic disease underwent mesenteric revascularization during other aortic-based operations. Fourteen patients (93%) had 10 mesenteric bypasses (8 aortic based; 2 iliac), three had aortoplasties, of which two had mesenteric patch angioplasties, and one underwent arcuate ligament release with patch angioplasty. One patient (7%) underwent percutaneous transluminal angioplasty of SMA stenosis. There were no early deaths. Early complications occurred in three patients (20%) after open reconstruction, including gastrointestinal hemorrhage, ileus with re-exploration, and superior mesenteric vein thrombosis. Median follow-up was 22 months. One graft thrombosis in a patient with active disease was treated with redo bypass 74 months after aorta-celiac-SMA bypass. All patients were alive at 10 years, with similar expected survival compared with the general population (P = .69). Compared with patients with atherosclerotic disease, open reconstructions for MV had similar freedom from mesenteric symptoms (83% vs 75%, P = .80) and similar primary graft patency (83% vs 84%, P = .9).

CONCLUSION

Mesenteric vasculitis is a rare manifestation of Takayasu arteritis, polyarteritis nodosa, indeterminate, or giant cell arteritis. Open revascularization is durable and effective when needed.

Anesthetic management of acute mesenteric ischemia in elderly patients

Ischemic insult to the splanchnic vasculature can jeopardize bowel viability and lead to devastating consequences, including bowel necrosis and gangrene. Although acute mesenteric ischemia (AMI) may occur at any age, the elderly are most commonly affected due to their higher incidence of underlying systemic pathology, most notably atherosclerotic cardiovascular disease. Treatment options include pharmacology-based actions, endovascular, and surgical interventions. AMI remains a life-threatening condition with a mortality rate of 60% to 80%, especially if intestinal infarction has occurred and surgical intervention becomes emergent. Early recognition and an aggressive therapeutic approach are essential if the usually poor outcome is to be improved. Anesthetic management is complex and must account for comorbid disease as well as the patient's presumptive acute deterioration. Blood pressure support typically involves careful, but often massive, fluid resuscitation and may also additionally require pharmacologic support.

Isolated ileocolic artery occlusion presented with segmental bowel infarction: a case report

Acute mesenteric ischemia is a serious acute abdominal condition requiring early diagnosis and intervention to improve the outcome. Although transmural acute bowel infarction represents about 1% of all cases of acute abdomen, it has a higher annual mortality rate than colon cancer. It tends to affect the colon in segmental fashion, mostly the splenic flexure and rectosigmoid portions of the colon. Isolated ischemia of the right side of the colon is rarely reported, especially in association with shock. Diagnosis of acute colonics ischemia is challenging as it may easily be confused with other non ischemic conditions both clinically and radiologically. Surgical resection is still the main curative approach. We present a case of segmental terminal ileum, cecum and part of ascending colon infarction due to isolated IleoColic artery thrombosis.

Mesenteric venous thrombosis and factors associated with mortality: a statistical analysis with five-year follow-up

OBJECTIVE

The objective was to study the factors associated with mortality in mesenteric venous thrombosis (MVT).

METHODS

We reviewed all cases of bowel ischemia at our institute from 1984 to 2004 and identified 31 cases of MVT and compiled data concerning their demographics, risk factors, investigations, management, surgical procedures, and outcomes. Survival was analyzed for both 30-day and 5-year periods.

RESULTS

Analysis of factors associated with mortality in our 31 case series revealed that 30-day mortality was strongly associated with colonic involvement in ischemia (p = .008) as well as short bowel syndrome (p = .028) and possibly failure to anti-coagulate the patient (p = .07). While 5-year mortality was strongly associated with "short bowel syndrome" as defined by small bowel remaining less than 100 cm (p = .031). Further study using a multivariate Cox proportional hazard analysis showed that mortality within the 30-day period was mainly related to colon ischemia with p value of .014 and an odds ratio of 17.4, while short-bowel syndrome was the predominated factor in the 5-year mortality analysis with a p value of .029 and an odds ratio of 5.

CONCLUSION

Thirty-day mortality for MVT is strongly associated with colonic involvement as well as "short-bowel" syndrome, while anticoagulation may be protective. Five-year survival was found to be strongly associated with "short-bowel" syndrome.

TLR4-mediated Cox-2 expression increases intestinal ischemia/reperfusion-induced damage

Mesenteric IR induces significant inflammation and immune-mediated mucosal damage. TLR4 is a critical receptor in the induction of the inflammatory response and plays a role in intestinal homeostasis. To determine the role of TLR4 in IR-induced epithelial damage, we performed IR studies using TLR4(lps-def) and TLR4(lps-n) mice and analyzed mucosal damage and inflammation. We found that the absence of TLR4 or TLR4-induced signaling attenuated local mucosal damage with significantly decreased cytokine and eicosanoid secretion including PGE2 production. Similar results were seen in MyD88-/- mice. Wild-type mice treated with NS-398 (a Cox-2 inhibitor) not only decreased PGE2 production but also attenuated tissue damage. In contrast, PGE2 was not sufficient to induce damage in the TLR4(lps-def) mice. Together, these data indicate that TLR4 stimulation of Cox-2 activation of PGE2 production is necessary but not sufficient for intestinal IR-induced damage and inflammation.