Intestinal ischemia

Understanding CT imaging findings based on the underlying pathophysiology in patients with small bowel ischemia

Because acute small bowel ischemia has a high mortality rate, it requires rapid intervention to avoid unfavorable outcomes. Computed tomography (CT) examination is important for the diagnosis of bowel ischemia. Acute small bowel ischemia can be the result of small bowel obstruction or mesenteric ischemia, including mesenteric arterial occlusion, mesenteric venous thrombosis, and non-occlusive mesenteric ischemia. The clinical significance of each CT finding is unique and depends on the underlying pathophysiology. This review describes the definition and mechanism(s) of bowel ischemia, reviews CT findings suggesting bowel ischemia, details factors involved in the development of small bowel ischemia, and presents CT findings with respect to the different factors based on the underlying pathophysiology. Such knowledge is needed for accurate treatment decisions.

Associations between SARS-CoV-2 infections and thrombotic complications necessitating surgical intervention: A systematic review

BACKGROUND

Several unique clinical features of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19) infection, have been identified and characterized. One such feature, mostly among patients with severe COVID-19 infection, has become known as COVID-19-induced coagulopathy. Surgical patients with a history of or active COVID-19 infection bear a significantly higher risk for postoperative thrombotic complications. These patients may require surgical intervention to treat severe thrombotic complications. Few studies have been carried out to better characterize this association. The purpose of this study was to perform a systematic review and meta-analysis of the literature on COVID-19 infections that led to thrombotic complications necessitating surgical intervention. We hypothesized that patients with recent or active COVID-19 infection would have high rates of thromboembolic complications both arterial and venous in origin.

AIM

To perform a systematic review and meta-analysis of the literature on COVID-19 infections that led to thrombotic complications necessitating surgical intervention.

METHODS

The current systematic review implemented an algorithmic approach to review all the currently available English medical literature on surgical interventions necessitated by COVID-19 thrombotic complications using the preferred reporting items for systematic reviews and meta-analysis principles. A comprehensive search of the medical literature in the "PubMed", "Scopus", "Google Scholar" top 100 results, and archives of Plastic and Reconstructive Surgery was performed using the key words "COVID-19" AND "surgery" AND "thromboembolism" AND "complication". The search string was generated and the records which were not specific about surgical interventions or thrombotic complications due to COVID-19 infection were excluded. Titles and abstracts were screened by two authors and full-text articles were assessed for eligibility and inclusion. Finally, results were further refined to focus on articles that focused on surgical interventions that were necessitated by COVID-19 thrombotic complications.

RESULTS

The database search resulted in the final inclusion of 22 retrospective studies, after application of the inclusion/exclusion criteria. Of the included studies, 17 were single case reports, 3 were case series and 2 were cross sectional cohort studies. All studies were retrospective in nature. Twelve of the reported studies were conducted in the United States of America, with the remaining studies originating from Italy, Turkey, Pakistan, France, Serbia, and Germany. All cases reported in our study were laboratory confirmed SARS-CoV-2 positive. A total of 70 cases involving surgical intervention were isolated from the 22 studies included in this review.

CONCLUSION

There is paucity of data describing the relationship between COVID-19 infection and thrombotic complications necessitating the need for surgical intervention. Intestinal ischemia and acute limb ischemia are amongst the most common thrombotic events due to COVID-19 that required operative management. An overall postoperative mortality of 30% was found in those who underwent operative procedures for thrombotic complications, with most deaths occurring in those with bowel ischemia. Physicians should be aware that despite thromboprophylaxis, severe thrombotic complications can still occur in this patient population, however, surgical intervention results in relatively low mortality apart from cases of ischemic bowel resection.

Ultrasound Detection of Portomesenteric Venous Gas Is an Early Sign of Bowel Ischaemia in Non-Traumatic Abdominal Pain: Old Dogs, New Tricks—Four Cases Report

Acute bowel ischemia is a severe disease often with a poor outcome. Early diagnosis can improve outcome, but atypical clinical manifestations and nonspecific laboratory and instrumental diagnostic findings may delay computed tomographic angiography (CTA). Portomesenteric venous gas (PVG), indirect sign of pneumatosis intestinalis, is considered a late finding with poor prognosis. We report four cases where PVG, easily identified through point-of-care ultrasonography (POCUS), was an early sign of bowel ischemia leading to a precocious diagnosis confirmed at CTA. In acute non-traumatic abdominal pain, an evidence of PVG could be an early ultrasonographic finding of bowel ischemia in the emergency department.

Use of Diagnosis Codes to Find Blood Transfusion Adverse Events in Electronic Health Records

OBJECTIVE

Electronic health records (EHRs) and big data tools offer the opportunity for surveillance of adverse events (patient harm associated with medical care). We used International Classification of Diseases, Ninth Revision, codes in electronic records to identify known, and potentially novel, adverse reactions to blood transfusion.

METHODS

We used 49,331 adult admissions involving critical care at a major teaching hospital, 2001-2012, in the Medical Information Mart for Intensive Care III EHRs database. We formed a T (defined as packed red blood cells, platelets, or plasma) group of 21,443 admissions versus 25,468 comparison (C) admissions. The International Classification of Diseases, Ninth Revision, Clinical Modification , diagnosis codes were compared for T versus C, described, and tested with statistical tools.

RESULTS

Transfusion adverse events (TAEs) such as transfusion-associated circulatory overload (TACO; 12 T cases; rate ratio [RR], 15.61; 95% confidence interval [CI], 2.49-98) were found. There were also potential TAEs similar to TAEs, such as fluid overload disorder (361 T admissions; RR, 2.24; 95% CI, 1.88-2.65), similar to TACO. Some diagnoses could have been sequelae of TAEs, including nontraumatic compartment syndrome of abdomen (52 T cases; RR, 6.76; 95% CI, 3.40-14.9) possibly being a consequence of TACO.

CONCLUSIONS

Surveillance for diagnosis codes that could be TAE sequelae or unrecognized TAE might be useful supplements to existing medical product adverse event programs.

Time limit to rescue intestine with viability at risk caused by blood flow disruption in patients presenting with acute abdomen

Purpose

Early management is crucial for acute intestinal blood flow disorders; however, no published study has identified criteria for the time limit for blood flow resumption. This study specifically examines the time factors for avoiding intestinal resection.

Methods

The subjects of this retrospective cohort study were 125 consecutive patients who underwent emergency surgery for a confirmed diagnosis of intestinal strangulation (n = 86), incarceration (n = 27), or volvulus (n = 12), between January 2015 and March 2021. Intestinal resection was performed when intestinal irreversible changes had occurred even after ischemia was relieved surgically. We analyzed the relationship between the time from computed tomography (CT) imaging to the start of surgery (C-S time) and intestinal resection using the Kaplan–Meier method and calculated the estimated intestinal rescue rate. Patient background factors affecting intestinal resection were also examined.

Results

The time limit for achieving 80% intestinal rescue rate was 200 min in C-S time, and when this exceeded 300 min, the intestinal rescue rate dropped to less than 50%. Multivariate analysis identified the APACHE II score as a significant influencing factor.

Conclusion

A rapid transition from early diagnosis to early surgery is critical for patients with acute abdomen originating from intestinal blood flow disorders. The times from presentation at the hospital to surgery should be reduced further, especially for severe cases.

Intraoperative quality assessment of tissue perfusion with indocyanine green (ICG) in a porcine model of mesenteric ischemia

Background

Mesenteric ischemia is a severe and potentially lethal event. Assessment of intestine perfusion is eminently depending on the skills, and the experience of the surgeon. Thus, the therapy is biased by the right evaluation. Aim of this study is to determine the applicability, and the usefulness of fluorescent-imaging (FI) with indocyanine green (ICG) in a porcine model of mesenteric ischemia. Second end-point is the verification of a visual and quantitative assessment tool of the intestinal perfusion.

Methods

In 18 pigs (54,2 ±2,9kg) an occlusion of a side-branch of the mesenteric artery was performed for 3 (group I, n = 7), 6 (group II, n = 7), and 10 hours (group III, n = 4). After reperfusion a 60 minutes observation period was carried out. 3 regions of interest were defined: ischemic bowel (D1), transitional zone (D2), and non-ischemic bowel (D3). ICG-FI was performed during baseline (T0), occlusion (T1), reperfusion (T2) and after an observation period of 60 minutes (T4).

Results

All experiments could be finished successfully. ICG-FI was assessed using assessment of background-subtracted peak fluorescence intensity (BSFI), slope of fluorescence intensity (SFI), and a baseline adjusted ratio of both parameters. ICG-FI confirmed loss of perfusion in D1, decreased perfusion in D2, and increased perfusion in D3. After reperfusion ICG-FI increased in group 2 due to a severe tissue damage resulting in a capillary leakage. In group I ICG-FI was equal to baseline values indicating the totally reversible loss of perfusion.

Conclusion

Using ICG-FI to estimate intestine perfusion after different durations of ischemia is viable using a porcine model of mesenteric ischemia. Even small differences in perfusion can be reliably determined by ICG-FI. Thus, ICG-FI is an encouraging method to evaluate intestine perfusion intraoperatively.

A Novel Method of Damage Control for Multiple Discontinuous Intestinal Injuries with Hemorrhagic Shock: A Controlled Experiment

Aim: In this study, we examined the effects of branched silicon tube (BST) and temporary closed circle (TCC) in a Beagle dog model of multiple transection of small intestine and discontinuities suspected intestinal necrosis with hemorrhagic shock. Materials and Methods: Ten male Beagle dogs were randomly divided into two groups. Hemorrhagic shock was induced by bleeding. Intestine was severed. Suspected intestinal necrotic model by ligating the mesenteric vessels was established, with a small tertiary mesenteric vessel reserved. Fracted intestines were ligated (IL group, n = 5) or reconnected with BST (IR group, n = 5). The abdominal cavity was temporarily closed with TCC. Definitive surgery was conducted after 24 h. Results: There was no statistical difference between two groups in the weight of dogs, their blood loss, fluid resuscitation, operation time of early emergency treatment (EET). After definitive surgery, all dogs in IR group and 3 dogs in IL groups were alive. 18 (90%) suspicious necrotic intestinal segments in IL group became necrotic, but 20 (80%) segments in IR group didn't develop obvious changes (p < 0.01). From 2 h after EET, the endotoxin concentration in IL group was significantly higher than that in IR group (133.87 ± 43.73 vs. 56.31 ± 24.70 pg/ml, p < 0.01). Microscopic examination revealed that much more severe damage occurred in the suspicious necrotic intestinal segments in IL group. Conclusion: Both reconnecting intestine with BST and temporary abdominal closure with TCC are viable methods of damage control for multiple discontinuous intestinal injuries.

Biological scoring system for early prediction of acute bowel ischemia after cardiac surgery: the PALM score

Background

Bowel ischemia is a life-threatening emergency defined as an inadequate vascular perfusion leading to bowel inflammation resulting from impaired colonic/small bowel blood supply. Main issue for physicians regarding bowel ischemia diagnosis lies in the absence of informative and specific clinical or biological signs leading to delayed management, resulting in a poorer prognosis, especially after cardiac surgery. The aim of the present series was to propose a simple scoring system based on biological data for the diagnosis of bowel ischemia.

Methods

In a retrospective monocentric study, patients admitted in cardiac ICU, after cardiovascular surgery, were screened for inclusion. According to a 1:2 ratio (case–control), matching between two groups was based on sex, type of cardiovascular surgery, and the operative period (per month). Patients were divided into two groups: “ischemic group” which corresponds to patients with confirmed bowel ischemia and “non-ischemic group” which corresponds to patients without bowel ischemia. Primary objective was the conception of a scoring system for the diagnosis of bowel ischemia. Secondary objectives were to detail the postoperative morbidity and the diagnostic features for the distinction between acute mesenteric ischemia and ischemic colitis.

Results

Forty-eight patients (1.3%) had confirmed bowel ischemia (“ischemic group”). According to the 2:1 matching, 96 patients were included in the “non-ischemic group.” Aspartate aminotransferase > 449 UI/L, lactate > 4 mmol/L, procalcitonin > 4.7 μg/L, and myoglobin > 1882 μg/L were found to be independently associated with bowel ischemia. Based on their respective odds ratios, points were assigned to each item ranging from 4 to 8. AUROCC [95% confidence interval] of the scoring system to diagnose bowel ischemia was 0.93 [0.91–0.95], p < 0.001. The optimal threshold after bootstrapping was ≥ 14 points; this yielded a sensitivity of 85.4%, a specificity of 94.8%, a positive likelihood ratio of 16.42, a negative likelihood ratio of 0.15, a Youden’s index of 0.802, and a diagnostic odds ratio of 106.62.

Conclusions

A biological scoring system based on PCT, ASAT, lactate, and myoglobin measurement allows the diagnosis of bowel ischemia after cardiac surgery with high accuracy. This score could help clinician to propose an early diagnosis and an early treatment in this high mortality disease.

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0395-5) contains supplementary material, which is available to authorized users.

Progress in multi-slice CT diagnosis of atherosclerotic mesenteric ischemia

The incidence of atherosclerotic mesenteric ischemia increases gradually with the aging of the population and rising of the incidence of atherosclerosis. In the last decade, mesenteric atherosclerosis has become the most common cause of acute and chronic mesenteric ischemia. Atherosclerotic mesenteric ischemia often presents with an insidious onset and slow evolvement, and is easily overlooked. The CT manifestations of advanced mesenteric ischemia are classic with high diagnostic accuracy, and the specific findings of CT angiography include: thromboembolus and stenotic or occlusive mesenteric artery in acute stage, single or multiple calcified or non-calcified plaques, and multiple stenotic and stiff mesenteric arteries with reduced branching vessels in chronic stage. Early mesenteric ischemia, however, has no or nonspecific CT sign and is difficult to detect. This article discusses the diagnostic value and limitations of multi-slice CT in atherosclerotic mesenteric ischemia as well as some new imaging techniques for diagnosis of this condition.

Oesophageal pneumatosis in a case of bowel ischaemia

Pneumatosis intestinalis (PI) is a condition in which cystic collections of gas develop within the gastrointestinal wall, forming submucosal or subserosal "bubbles". The radiologic manifestations are often dramatic and most notably are associated with life-threatening bowel ischaemia. PI may occur as a primary type but is usually secondary in nature, attributable to a wide spectrum of causes (benign and fulminant), ranging from immunosuppression to bowel infarction. Herein, we report a case of massive and extensive PI in a patient with small bowel ischaemia, having both benign and serious clinical origins.

Serum procalcitonin correlates with colonoscopy findings and can guide therapeutic decisions in postoperative ischemic colitis

BACKGROUND

Postoperative ischaemic colitis (POIC) is a life-threatening vascular gastrointestinal condition. Serum procalcitonin (PCT) levels be of value in the detection of necrosis.

AIMS

To evaluate the correlation between serum PCT levels and the colonoscopic assessment of the severity of POIC.

METHODS

Between January 2007 and November 2014, 150 patients with POIC and PCT data were included in the study. The main outcome measure was the correlation between serum PCT and the colonoscopy-based assessment of the severity of POIC (according to Favier's classification: stage 1/2 without multi-organ failure vs. stage 2/3 with multi-organ failure).

RESULTS

Eighty-five percent of the stage 1 cases (n=22) had a serum PCT level ≤2μg/L; 63% (n=19) of the stage 2 cases with multi-organ failure had a PCT level between 4 and 8μg/L, and 70% (n=52) of the stage 3 cases had a PCT level ≥8μg/L. The PCT level was strongly correlated with the Favier stage (Spearman's rho: 0.701; p<0.0001). PCT levels were similar in stage 2 cases with multi-organ failure and in stage 3 cases (16.06μg/L vs. 7.79μg/L, respectively; p=0.35).

CONCLUSION AND RELEVANCE

Serum PCT is correlated with stage 2/3 POIC requiring surgery. If PCT ≥5μg/L, surgery should be considered.

Influence of splanchnic artery stenosis on the in-hospital clinical course of elderly patients

BACKGROUND

Chronic mesenteric ischaemia (CMI) has a long asymptomatic period, but little is known about the clinical implications of this phase of the disease, particularly in the elderly, who are most exposed to the condition.

AIMS

The aim of the present observational study was to survey the in-hospital clinical course of elderly patients during the non-specific phase of the disease due to occlusion of at least one splanchnic artery.

METHODS

For a median of 29 months, we followed up 85 patients aged 65 and over who, for various clinical reasons, had undergone computed tomographic and magnetic resonance angiography during 2010 at Padua Teaching Hospital, assessing economic impact and reasons for admission.

RESULTS

Thirty-four of these patients had at least one occluded artery, and 68 % of them had at least one hospital admission. Elderly CMI patients were characterised by a higher number of admissions (median 2 vs 1 p = 0.05) and a higher cost (6044 vs 1733 Euros p = 0.04), but did not present typical gastrointestinal symptoms. The higher number of hospital admissions was not due to specific clinical risks (admitting wards: general medicine: 32 vs 29 %, p = 0.77; general surgery 8 vs 14 %, p = 0.73; vascular surgery: 26.5 vs 20 %, p = 0.46).

CONCLUSIONS

In the asymptomatic phase of CMI, hospitalised elderly patients with at least one occluded splanchnic artery can be subject to a more challenging in-hospital clinical course.

Distinct cytoprotective roles of pyruvate and ATP by glucose metabolism on epithelial necroptosis and crypt proliferation in ischaemic gut

KEY POINTS

Intestinal ischaemia causes epithelial death and crypt dysfunction, leading to barrier defects and gut bacteria-derived septic complications. Enteral glucose protects against ischaemic injury; however, the roles played by glucose metabolites such as pyruvate and ATP on epithelial death and crypt dysfunction remain elusive. A novel form of necrotic death that involves the assembly and phosphorylation of receptor interacting protein kinase 1/3 complex was found in ischaemic enterocytes. Pyruvate suppressed epithelial cell death in an ATP-independent manner and failed to maintain crypt function. Conversely, replenishment of ATP partly restored crypt proliferation but had no effect on epithelial necroptosis in ischaemic gut. Our data argue against the traditional view of ATP as the main cytoprotective factor by glucose metabolism, and indicate a novel anti-necroptotic role of glycolytic pyruvate under ischaemic stress.

ABSTRACT

Mesenteric ischaemia/reperfusion induces epithelial death in both forms of apoptosis and necrosis, leading to villus denudation and gut barrier damage. It remains unclear whether programmed cell necrosis [i.e. receptor-interacting protein kinase (RIP)-dependent necroptosis] is involved in ischaemic injury. Previous studies have demonstrated that enteral glucose uptake by sodium-glucose transporter 1 ameliorated ischaemia/reperfusion-induced epithelial injury, partly via anti-apoptotic signalling and maintenance of crypt proliferation. Glucose metabolism is generally assumed to be cytoprotective; however, the roles played by glucose metabolites (e.g. pyruvate and ATP) on epithelial cell death and crypt dysfunction remain elusive. The present study aimed to investigate the cytoprotective effects exerted by distinct glycolytic metabolites in ischaemic gut. Wistar rats subjected to mesenteric ischaemia were enterally instilled glucose, pyruvate or liposomal ATP. The results showed that intestinal ischaemia caused RIP1-dependent epithelial necroptosis and villus destruction accompanied by a reduction in crypt proliferation. Enteral glucose uptake decreased epithelial cell death and increased crypt proliferation, and ameliorated mucosal histological damage. Instillation of cell-permeable pyruvate suppressed epithelial cell death in an ATP-independent manner and improved the villus morphology but failed to maintain crypt function. Conversely, the administration of liposomal ATP partly restored crypt proliferation but did not reduce epithelial necroptosis and histopathological injury. Lastly, glucose and pyruvate attenuated mucosal-to-serosal macromolecular flux and prevented enteric bacterial translocation upon blood reperfusion. In conclusion, glucose metabolites protect against ischaemic injury through distinct modes and sites, including inhibition of epithelial necroptosis by pyruvate and the promotion of crypt proliferation by ATP.

Debate: Whether an endovascular-first strategy is the optimal approach for treating acute mesenteric ischemia

Acute mesenteric ischemia continues to be a life-threatening insult in often-elderly patients with many comorbidities. Recognition and correct diagnosis can be an issue leading to delays in therapy that result in loss of bowel or life, or both. The basic surgical principals in treating acute mesenteric ischemia have long been early recognition, resuscitation, urgent revascularization, resection of necrotic bowel, and reassessment with second-look laparotomies. Endovascular techniques now offer a less invasive alternative, but whether an endovascular-first or open surgery-first approach is preferred in most patients is unclear. Our discussants will attempt to clarify these issues.

Sensitivity and specificity of red cell distribution width in diagnosing acute mesenteric ischemia in patients with abdominal pain

BACKGROUND

We investigated the utility of the red cell distribution width (RDW) in diagnosing acute mesenteric ischemia (AMI) in patients with abdominal pain.

METHODS

The patients were divided into two groups in this retrospective case-control study: patients with AMI and patients with abdominal pain who did not require urgent surgery. Venous blood was collected from the patients upon admission to the emergency department, and abdominal computed tomography angiography was performed. The RDW and hematological and biochemical parameters of the groups were compared. The primary outcome was AMI among the patients with abdominal pain. The secondary outcome was mortality, complaint period, and size of ischemia/necrosis among the AMI patients.

RESULTS

The RDW, white blood cell lactate dehydrogenase, and blood urea nitrogen of the patients with AMI were significantly different from those of the control group. When the average RDW (15.04 %) of the patients with AMI was used as a cut-off value, the sensitivity, specificity, positive likelihood ratio (+LR), and negative likelihood (-LR) were 40.8 %, 81.2 %, 2.17, and 0.73, respectively. When patients with AMI and anemia were included in the group, the sensitivity and specificity values did not change. There was no relation between the RDW and mortality, size of the ischemia/necrosis, and complaint period. Furthermore, there was no significant difference in the average RDW between the patients with ischemia/necrosis in the small intestine only and those with ischemia/necrosis in the colon.

CONCLUSION

The RDW on admission is of marginal help to diagnose AMI among patients with abdominal pain.

Neutrophil-to-lymphocyte ratio as a diagnostic biomarker for the diagnosis of acute mesenteric ischemia

PURPOSE

Due to the diagnostic challenges and dreadful consequences of delayed treatment of acute mesenteric ischemia (AMI), a variety of diagnostic markers have been previously studied. However, the diagnostic value of neutrophil-to-lymphocyte ratio (NLR), which has been suggested to be a predictor of inflammation, has never been studied for AMI.

METHODS

The data of 70 patients who underwent laparotomy (n = 8) and/or bowel resection (n = 62) for AMI (n = 70) between January 2009 and March 2014 were retrospectively analyzed. To investigate the studied parameters' role in the differential diagnosis of AMI, control groups were selected from most common reasons of inflammation-related emergent surgery, acute appendicitis (AA, n = 62) and normal appendix (NA, n = 61). White blood cell (WBC), red cell distribution width (RDW), NLR and mean platelet volume (MPV) values were recorded. Outcome variables of the study were defined as diagnostic and prognostic role of NLR in AMI.

RESULTS

RDW and NLR values were found to be higher in the AMI group than the AA group (p < 0.001 and p < 0.001). Also, WBC and MPV values were higher in the AMI group than the NA group (p = 0.001 and p < 0.001). Combined sensitivity, specificity, positive predictive value and negative predictive value of RDW and NLR for recommended cut-off values were 69.4, 71.2, 57.8 and 80.4 %, respectively.

CONCLUSION

High NLR value (>9.9) seems to be a valuable diagnostic marker of acute mesenteric ischemia. Combined use of NLR, RDW and other clinical assessment, could help the diagnosis of AMI, especially in the absence of advanced imaging modalities and expert radiologic interpretation.

Serum value of procalcitonin as a marker of intestinal damages: type, extension, and prognosis

BACKGROUND

Ischemic and necrotic damages are complications of digestive diseases and require emergency management. Nevertheless, the decision to surgically manage could be delayed because of no sufficiently preoperative accurate marker of ischemia diagnosis, extension, and prognosis.

METHODS

The aim of this study was to assess the predictive value of serum procalcitonin (PCT) levels for diagnosing intestinal necrotic damages, their extension, and their prognosis in patients with ischemic disease including ischemic colitis and mesenteric infarction by a gray zone approach. Between January 2007 to June 2014, 128 patients with ischemic colitis and mesenteric infarction (codes K55.0 and K51.9) were operated, for whom data on PCT were available. We perform a retrospective, multicenter review of their medical records. Patients were divided into subgroups: ischemia (ID group) versus necrosis (ND group); the extension [focal (FD) vs. extended (ED)] and the vital status [deceased (D) vs. alive (A)].

RESULTS

PCT levels were higher in the ND (n = 94; p = 0.009); ED (n = 100; p = 0.02); and D (n = 70; p = 0.0003) groups. With a gray zone approach, the predictive thresholds were (i) for necrosis 2.473 ng/mL, (ii) for extension 3.884 ng/mL, and (iii) for mortality 7.87 ng/mL.

CONCLUSION

In our population, PCT could be used as a marker of necrosis; especially in case of extended damages and reflects the patient's prognosis.

The length of necrosis and renal insufficiency predict the outcome of acute mesenteric ischemia

BACKGROUND

Acute mesenteric ischemia (AMI) is a potentially life-threatening condition because of its diagnostic difficulty, operative challenges, and comorbidities a patient may have. The aim of this study was to identify factors associated with adverse outcomes in patients with AMI.

METHODS

The hospital records and clinical data of all patients with AMI were reviewed for a recent 4-year period. Clinical outcomes and factors influencing mortality were analyzed.

RESULTS

Included in the study were 104 patients (46 females and 58 males) with an overall mean age of 66 ± 13.4 years. The cause of AMI was arterial pathology in 74 (71%) patients, venous thrombosis in 15 (14%) patients, and nonocclusive ischemia in 12 (12%) patients. Abdominal pain was the most common presenting symptom (97% of patients). The 30-day mortality rate was 66%. Univariate analysis showed that mortality was associated with renal insufficiency (p = 0.004), an age greater than 70 years (p = 0.02), the presence of comorbidities (p = 0.001), a leukocyte count greater than 18,000/mL (p = 0.04), and small bowel necrosis of more than 100 cm (p < 0.0001). Logistic regression analysis showed that independent predictors of mortality were small bowel necrosis of more than 100 cm (p = 0.002) and a serum creatinine level greater than 2 mg/dL (p = 0.04).

CONCLUSION

The length of the necrosis and renal insufficiency are the primary factors that result in a poor outcome in AMI patients. Prompt diagnostic evaluation and early therapeutic interventions may help to prevent the development of these fatal predictors.

Investigating viability of intestine using spectroscopy: a pilot study

BACKGROUND

The differentiation of "viable" from "nonviable" bowel remains a challenge in the treatment of acute mesenteric ischemia. In this study, diffuse reflectance spectroscopy (DRS) was used to investigate the viability of bowel tissue after ischemia and reperfusion in an animal model in vivo and in real time.

METHODS

A total of 25 females Sprague-Dawley rats were divided into five groups based on different bowel ischemia times. In each study group for four of them, the superior mesenteric artery was occluded using a vascular clamp for a different period (i.e., 30, 45, 60, and 90 min; n = 5 for each group). Intestinal reperfusion was accomplished by releasing the clamps after the given occlusion period for each group. Spectra were acquired by gently touching the optical fiber probe to the bowel tissue before the induce ischemia, at the end of the induced ischemia, and after the reperfusion. The data acquired before the ischemia were used as a control group. Without occluding the superior mesenteric artery, the spectra were acquired on the bowel with the same time intervals of the experiments were used as a sham group (n = 5). Subsequently, the same bowel segments were sent for histopathologic examination.

RESULTS

Based on the correlation between the spectra acquired from the bowel segments and the results from the histopathologic investigation, DRS is able to differentiate the histopathologic grading that appears when the Chiu/Park score ≥5 (i.e., high-level ischemic injury) than Chiu/Park score <5. Eight out of nine low-level ischemic injury tissue samples were correctly defined using the spectroscopic classification system. All eleven high-level ischemic injury tissues that were histopathologically assigned grade 5 and above were correctly defined using the spectroscopic classification system in the ischemia-reperfusion groups.

CONCLUSIONS

DRS could potentially be used intraoperatively for the assessment of bowel viability in real time. These preliminary findings suggest that DRS has the potential to reduce unnecessary resection of viable tissue or insufficient resection of nonviable tissues may reduce the mortality and morbidity rates of intestinal ischemia-reperfusion as acute mesenteric ischemia.

Comparison of open and endovascular treatment of acute mesenteric ischemia

INTRODUCTION

Acute mesenteric ischemia (AMI) is a commonly fatal result of inadequate bowel perfusion that requires immediate evaluation by both vascular and general surgeons. Treatment often involves vascular repair as well as bowel resection and the possible need for parenteral nutrition. Little data exist regarding the rates of bowel resection following endovascular vs open repair of AMI.

METHODS

Using the National Inpatient Sample database, admissions from 2005 through 2009 were identified according to International Classification of Diseases, Ninth Revision codes correlating to both AMI (557.0) and subsequent vascular intervention (39.26, 38.16, 38.06, 39.9, 99.10). Patients with a diagnosis of AMI but no intervention or nonemergent admission status were excluded. Patient level data regarding age, gender, and comorbidities were also examined. Outcome measures included mortality, length of stay, the need for bowel resection (45.6, 45.71-9, 45.8), or infusion of total parenteral nutrition (TPN; 99.10) during the same hospitalization. Statistical analysis was conducted by χ(2) tests and Wilcoxon rank-sum comparisons.

RESULTS

Of 23,744 patients presenting with AMI, 4665 underwent interventional treatment from 2005 through 2009. Of these patients, 57.1% were female, and the mean age was 70.5 years. A total of 679 patients underwent vascular intervention; 514 (75.7%) underwent open surgery and 165 (24.3%) underwent endovascular treatment overall during the study period. The proportion of patients undergoing endovascular repair increased from 11.9% of patients in 2005 to 30.0% in 2009. Severity of comorbidities, as measured by the Charlson index, did not differ significantly between the treatment groups. Mortality was significantly more commonly associated with open revascularization compared with endovascular intervention (39.3% vs 24.9%; P = .01). Length of stay was also significantly longer in the patient group undergoing open revascularization (12.9 vs 17.1 days; P = .006). During the study time period, 14.4% of patients undergoing endovascular procedures required bowel resection compared with 33.4% for open revascularization (P < .001). Endovascular repair was also less commonly associated with requirement for TPN support (13.7% vs 24.4%; P = .025).

CONCLUSIONS

Endovascular intervention for AMI had increased significantly in the modern era. Among AMI patients undergoing revascularization, endovascular treatment was associated with decreased mortality and shorter length of stay. Furthermore, endovascular intervention was associated with lower rates of bowel resection and need for TPN. Further research is warranted to determine if increased use of endovascular repair could improve overall and gastrointestinal outcomes among patients requiring vascular repair for AMI.

Acute arterial mesenteric ischemia and reperfusion: Macroscopic and MRI findings, preliminary report

AIM: To explore the physiopathology and magnetic resonance imaging (MRI) findings in an animal model of acute arterial mesenteric ischemia (AAMI) with and without reperfusion.

METHODS: In this study, 8 adult Sprague-Dawley rats underwent superior mesenteric artery (SMA) ligation and were then randomly divided in two groups of 4. In group I, the ischemia was maintained for 8 h. In group II, 1-h after SMA occlusion, the ligation was removed by cutting the thread fixed on the back of the animal, and reperfusion was monitored for 8 h. MRI was performed using a 7-T system.

RESULTS: We found that, in the case of AAMI without reperfusion, spastic reflex ileus, hypotonic reflex ileus, free abdominal fluid and bowel wall thinning are present from the second hour, and bowel wall hyperintensity in T2-W sequences are present from the fourth hour. The reperfusion model shows the presence of early bowel wall hyperintensity in T2-W sequences after 1 h and bowel wall thickening from the second hour.

CONCLUSION: Our study has shown that MRI can assess pathological changes that occur in the small bowel and distinguish between the presence and absence of reperfusion after induced acute arterial ischemia.

Computed tomography findings of pneumatosis and portomesenteric venous gas in acute bowel ischemia

AIM: To use more representative sample size to evaluate whether computed tomography (CT) scan evidence of the concomitant presence of pneumatosis and portomesenteric venous gas is a predictor of transmural bowel necrosis.

METHODS: Data from 208 patients who were referred for a diagnosis of bowel ischemia were retrospectively reviewed. Only patients who underwent a surgical intervention following a diagnosis of bowel ischemia who also had a post-operative histological confirmation of such a diagnosis were included. Patients were split into two groups according to the presence of histological evidence of transmural bowel ischemia (case group) or partial bowel ischemia (control group). CT images were reviewed for findings of ischemia, including mural thickening, pneumatosis, bowel distension, portomesenteric venous gas and arterial or venous thrombi.

RESULTS: A total of 248 subjects who underwent surgery for bowel ischemia were identified. Among the 208 subjects enrolled in our study, transmural bowel necrosis was identified in 121 subjects (case group), and partial bowel necrosis was identified in 87 subjects (control group). Based on CT findings, including mural thickening, bowel distension, pneumatosis, pneumatosis plus portomesenteric venous gas and presence of thrombi or emboli, there were no significant differences between the case and control groups. The concomitant presence of pneumatosis and porto-mesenteric venous gas showed an odds ratio of 1.95 (95%CI: 0.491-7.775, P = 0.342) for the presence of transmural necrosis. The presence of pneumatosis plus porto-mesenteric venous gas exhibited good specificity (83%) but low sensitivity (17%) in the identification of transmural bowel infarction. Accordingly, the positive and negative predictive values were 60% and 17%, respectively.

CONCLUSION: Although pneumatosis plus porto-mesenteric venous gas is associated with bowel ischemia, we have demonstrated that their co-occurrence cannot be used as diagnostic signs of transmural necrosis.

Treatment of mice with cromolyn sodium after reperfusion, but not prior to ischemia, attenuates small intestinal ischemia-reperfusion injury

Stabilizing mast cells (MCs) can either inhibit or augment inflammation; however, how improved therapeutic benefits against small intestinal ischemia-reperfusion injury (IIRI) can be achieved by stabilizing MCs remains to be elucidated. The present study was designed to evaluate different treatments with cromolyn sodium (CS, an MC stabilizer), which was administrated either prior to ischemia or after reperfusion. Kunming mice were randomized into a sham-operated group (SH), a sole IIR group (M), in which mice were subjected to 30 min superior mesenteric artery occlusion followed by 3 day or 3 h reperfusion, or IIR, treated with CS 15 min prior to ischemia or 15 min after reperfusion in the PreCr and PostCr groups. The survival rate and Chiu's scores were evaluated. The levels of ET-1, histamine, TNF-α and IL-6, and expression of MC protease 7 (MCP7), MC counts and myeloperoxidase (MPO) activity were quantified. IIR resulted in severe injury as demonstrated by significant increases in mortality and injury score. IIR also led to substantial elevations in the levels of ET-1, histamine, TNF-α and IL-6, expression of MCP7, MC counts and MPO activities (P<0.05, M vs. SH groups). All biochemical changes were markedly reduced in the PostCr group (P<0.05, PostCr vs. M groups), whereas pretreatment of IIR mice with CS prior to ischemia exhibited no changes of ET-1 levels, injury score and inflammation (P>0.05, PreCr vs. M groups). In conclusion, administration of CS after reperfusion, but not prior to ischemia, attenuates IIRI by downregulating ET-1 and suppressing sustained MC activation.

Chronic mesenteric ischemia: Time to remember open revascularization

Chronic mesenteric ischemia is caused by stenosis or occlusion of one or more visceral arteries. It represents a therapeutic challenge and diagnosis and treatment require close interdisciplinary cooperation between gastroenterologist, vascular surgeon and radiologist. Although endovascular treatment modalities have been developed, the number of restenoses ultimately resulting in treatment failure is high. In patients fit for open surgery, the visceral arteries should be revascularized conventionally. These patients will then experience long term relief from the symptoms, a better quality of life and a better overall survival.

Critical role of interleukin-17A in murine intestinal ischemia-reperfusion injury

Intestinal ischemia-reperfusion (I/R) injury causes severe illness frequently complicated by remote multiorgan dysfunction and sepsis. Recent studies implicated interleukin-17A (IL-17A) in regulating inflammation, autoimmunity, and I/R injury. Here, we determined whether IL-17A is critical for generation of intestinal I/R injury and subsequent liver and kidney injury. Mice subjected to 30 min of superior mesenteric artery ischemia not only developed severe small intestinal injury (necrosis, apoptosis, and neutrophil infiltration) but also developed significant renal and hepatic injury. We detected large increases in IL-17A in the small intestine, liver, and plasma. IL-17A is critical for generating these injuries, since genetic deletion of IL-17A- or IL-17A-neutralizing antibody treatment markedly protected against intestinal I/R injury and subsequent liver and kidney dysfunction. Intestinal I/R caused greater increases in portal plasma and small intestine IL-17A, suggesting an intestinal source for IL-17A generation. We also observed that intestinal I/R caused rapid small intestinal Paneth cell degranulation and induced murine α-defensin cryptdin-1 expression. Furthermore, genetic or pharmacological depletion of Paneth cells significantly attenuated the intestinal I/R injury as well as hepatic and renal dysfunction. Finally, Paneth cell depletion significantly decreased small intestinal, hepatic, and plasma IL-17A levels after intestinal I/R. Taken together, we propose that Paneth cell-derived IL-17A may play a critical role in intestinal I/R injury as well as extraintestinal organ dysfunction.

Metabolomic markers for intestinal ischemia in a mouse model

BACKGROUND

Diagnosis of intestinal ischemia remains a clinical challenge. The aim of the present study was to use a metabolomic protocol to identify upregulated and downregulated small molecules (M(r) < 500) in the serum of mice with intestinal ischemia. Such molecules could have clinical utility when evaluated as biomarkers in human studies.

METHODS

A mouse model for intestinal ischemia was established and validated using histology and serum tumor necrosis factor α concentrations. A second mouse model of peritoneal sepsis was used as a positive control. Serial serum samples were collected from these and from sham-operated animals. Sera were analyzed by gas chromatography-mass spectrometry for 40 small molecules as their trimethylsilyl and O-methyloxime derivatives. Peak areas were normalized against an internal standard and resultant peak area ratios subjected to multivariate data analysis using unsupervised principal components analysis and supervised orthogonal projection to latent structures-discriminant analysis. Upregulated and downregulated serum molecules were identified from their correlation to the orthogonal projection to latent structures-discriminant analysis model.

RESULTS

Three highly significantly upregulated (fold-change) serum molecules in intestinal ischemia were inorganic phosphate (2.4), urea (4.3), and threonic acid (2.9). Five highly significantly downregulated (fold-change) serum molecules were stearic acid (1.7), arabinose (2.7), xylose (1.6), glucose (1.4), and ribose (2.2). Lactic acid remained unchanged in intestinal ischemia.

CONCLUSIONS

Distinct molecular changes are reported here for the first time in intestinal ischemia. They reveal impairments of gut microbiota metabolism, intestinal absorption, and renal function, together with increased oxidative stress. In contrast to other reports, lactic acid was not significantly changed. These molecular signatures may now be evaluated in clinical studies.

Melanocortins as potential therapeutic agents in severe hypoxic conditions

Melanocortin peptides with the adrenocorticotropin/melanocyte-stimulating hormone (ACTH/MSH) sequences and synthetic analogs have protective and life-saving effects in experimental conditions of circulatory shock, myocardial ischemia, ischemic stroke, traumatic brain injury, respiratory arrest, renal ischemia, intestinal ischemia and testicular ischemia, as well as in experimental heart transplantation. Moreover, melanocortins improve functional recovery and stimulate neurogenesis in experimental models of cerebral ischemia. These beneficial effects of ACTH/MSH-like peptides are mostly mediated by brain melanocortin MC(3)/MC(4) receptors, whose activation triggers protective pathways that counteract the main ischemia/reperfusion-related mechanisms of damage. Induction of signaling pathways and other molecular regulators of neural stem/progenitor cell proliferation, differentiation and integration seems to be the key mechanism of neurogenesis stimulation. Synthesis of stable and highly selective agonists at MC(3) and MC(4) receptors could provide the potential for development of a new class of drugs for a novel approach to management of severe ischemic diseases.

Superior mesenteric arterial branch occlusion causing partial jejunal ischemia: a case report

Introduction

Ischemic bowel disease comprises both mesenteric ischemia and colonic ischemia. Mesenteric ischemia can be divided into acute and chronic ischemia. These are two separate entities, each with their specific clinical presentation and diagnostic and therapeutic modalities. However, diagnosis may be difficult due to the vague symptomatology and subtle signs.

Case presentation

We report the case of a 68-year-old Caucasian woman who presented with abdominal discomfort, anorexia, melena and fever. A physical examination revealed left lower quadrant tenderness and an irregular pulse. Computed tomography of her abdomen as well as computed tomography enterography, enteroscopy, angiography and small bowel enteroclysis demonstrated an ischemic jejunal segment caused by occlusion of a branch of the superior mesenteric artery. The ischemic segment was resected and an end-to-end anastomosis was performed. The diagnosis of segmental small bowel ischemia was confirmed by histopathological study.

Conclusion

Mesenteric ischemia is a pathology well-known by surgeons, gastroenterologists and radiologists. Acute and chronic mesenteric ischemia are two separate entities with their own specific clinical presentation, radiological signs and therapeutic modalities. We present the case of a patient with symptoms and signs of chronic mesenteric ischemia despite an acute etiology. To the best of our knowledge, this is the first report presenting a case of acute mesenteric ischemia with segmental superior mesenteric artery occlusion.