ESTES guidelines: acute mesenteric ischaemia

PURPOSE

Acute mesenteric ischaemia (AMI) accounts for about 1:1000 acute hospital admissions. Untreated, AMI will cause mesenteric infarction, intestinal necrosis, an overwhelming inflammatory response and death. Early intervention can halt and reverse this process leading to a full recovery, but the diagnosis of AMI is difficult and failure to recognize AMI before intestinal necrosis has developed is responsible for the high mortality of the disease. Early diagnosis and prompt treatment are the goals of modern therapy, but there are no randomized controlled trials to guide treatment and the published literature contains a high ratio of reviews to original data. Much of that data comes from case reports and often small, retrospective series with no clearly defined treatment criteria.

METHODS

A study group of the European Society for Trauma and Emergency Surgery (ESTES) was formed in 2013 with the aim of developing guidelines for the management of AMI. A comprehensive literature search was performed using the Medical Subject Heading (MeSH) thesaurus keywords "mesenteric ischaemia", "bowel ischaemia" and "bowel infarction". The bibliographies of relevant articles were screened for additional publications. After an initial systematic review of the literature by the whole group, a steering group formulated questions using a modified Delphi process. The evidence was then reviewed to answer these questions, and recommendations formulated and agreed by the whole group.

RESULTS

The resultant recommendations are presented in this paper.

CONCLUSIONS

The aim of these guidelines is to provide recommendations for practice that will lead to improved outcomes for patients.

Ischemic gastrointestinal complications of COVID-19: a systematic review on imaging presentation

Background

Limited data is available addressing gastrointestinal (GI) ischemia in coronavirus disease 2019 (COVID-19). We reviewed the clinical and radiologic features of GI ischemia and its related complications in thirty-one COVID-19 patients reported in literature.

Methods

A systematic literature review was performed using a search strategy on all studies published from January 1, 2020, to June 13, 2020, and updated on September 6, 2020, on databases from PubMed, Scopus, Embase, Web of Science, and Google Scholar. Every study with at least one presentation of COVID-19-related GI ischemia complication and one GI imaging finding was included.

Results

In total, twenty-two studies and thirty-one patients with the mean age of 59 ± 12.7 (age range: 28–80) years old were included, of which 23 (74.2%) patients were male, 7 (22.5%) female, and one unknown gender. The significant GI imaging findings include mesenteric arterial or venous thromboembolism, followed by small bowel ischemia. Nine patients (29%) presented with arterial compromise due to superior mesenteric thromboembolism, resulting in bowel ischemia. Also, 6 patients (19.3%) demonstrated occlusive thrombosis of the portal system and superior mesenteric vein. More than two-thirds of patients (20, 64.5%) required laparotomy and bowel resection. Eventually, five (16.1%) patients were discharged, of whom four cases (12.9%) readmitted. Five (16.1%) patients remained ICU hospitalized at the report time and 12 (38.7%) patients died.

Conclusion

Macrovascular arterial/venous thrombosis is identified in almost half of COVID-19 patients with bowel ischemia. Overall mortality in COVID-19 patients with GI ischemia and radiologically evident mesenteric thrombotic occlusion was 38.7% and 40%, retrospectively.

Indocyanine Green Tissue Angiography Can Reduce Extended Bowel Resections in Acute Mesenteric Ischemia

PURPOSE

Surgical exploration and bowel resection are frequently required for treating non-occlusive mesenteric ischemia. Intraoperative evaluation of intestinal perfusion is subjective and challenging. In this feasibility study, ICG fluorescence angiography was performed in order to evaluate intestinal perfusion in patients with acute mesenteric ischemia.

METHODS

This is a retrospective analysis of 52 patients who were operated for acute mesenteric ischemia using ICG fluorescence angiography. Patients with occlusive disease requiring recanalization were excluded. The SPY and PinPoint imaging systems were used for open and laparoscopic surgery, respectively. Intraoperative macroscopic assessment of perfusion was compared with the ICG angiography results.

RESULTS

Surgical exploration was performed for ischemia of the colon (n = 12), the small bowel (n = 23), or both (n = 16). One patient had ischemia of the esophagus and stomach. All patients had a preoperative CT angiography to rule out stenosis or occlusion of the mesenteric vessels. In 18 cases (34.6%), ICG fluorescence angiography provided information that was supplemental to macroscopic evaluation, but most patients did not survive the postoperative course. However, in six of those cases (11.5%), ICG angiography led to a major change in operative strategy resulting in a significant clinical benefit for those patients. For two cases, ICG fluorescence produced false negative results.

DISCUSSION

ICG tissue angiography is feasible and technically reliable for evaluating intestinal perfusion in acute mesenteric ischemia and led to a significant clinical benefit in 11% of our patients. A relevant discrepancy between surgical visual assessment and fluorescence angiography was found in 35% of the cases, which may help to define resection margins more accurately and thus support surgical decision-making.

HYPerspectral Enhanced Reality (HYPER): a physiology-based surgical guidance tool

BACKGROUND

HSI is an optical technology allowing for a real-time, contrast-free snapshot of physiological tissue properties, including oxygenation. Hyperspectral imaging (HSI) has the potential to quantify the gastrointestinal perfusion intraoperatively. This experimental study evaluates the accuracy of HSI, in order to quantify bowel perfusion, and to obtain a superposition of the hyperspectral information onto real-time images.

METHODS

In 6 pigs, 4 ischemic bowel loops were created (A, B, C, D) and imaged at set time points (from 5 to 360 min). A commercially available HSI system provided pseudo-color maps of the perfusion status (StO2, Near-InfraRed perfusion) and the tissue water index. An ad hoc software was developed to superimpose HSI information onto the live video, creating the HYPerspectral-based Enhanced Reality (HYPER). Seven regions of interest (ROIs) were identified in each bowel loop according to StO2 ranges, i.e., vascular (VASC proximal and distal), marginal vascular (MV proximal and distal), marginal ischemic (MI proximal and distal), and ischemic (ISCH). Local capillary lactates (LCL), reactive oxygen species (ROS), and histopathology were measured at the ROIs. A machine-learning-based prediction algorithm of LCL, based on the HSI-StO2%, was trained in the 6 pigs and tested on 5 additional animals.

RESULTS

HSI parameters (StO2 and NIR) were congruent with LCL levels, ROS production, and histopathology damage scores at the ROIs discriminated by HYPER. The global mean error of LCL prediction was 1.18 ± 1.35 mmol/L. For StO2 values > 30%, the mean error was 0.3 ± 0.33.

CONCLUSIONS

HYPER imaging could precisely quantify the overtime perfusion changes in this bowel ischemia model.

Ten-year review of isolated spontaneous mesenteric arterial dissections

OBJECTIVE

Isolated spontaneous dissection of the superior mesenteric artery (SMA) and celiac artery (CA) remains a rare condition; however, it has been increasingly noted incidentally on diagnostic imaging. The purpose of this study was to examine the natural history and outcomes of patients presenting with isolated spontaneous mesenteric artery dissection (SMAD). We hypothesized that most SMADs can be treated nonoperatively.

METHODS

This was a single-center retrospective review of patients presenting with the diagnosis of SMAD between 2006 and 2016. Data analysis included demographics, clinical data, radiologic review, treatment, and outcomes.

RESULTS

A total of 77 patients were found to have CA dissection, SMA dissection, or both in the absence of aortic dissection diagnosed on computed tomography or magnetic resonance imaging. The average age was 56 years (range, 26-86 years), 80% were male, and 10 patients (13%) had underlying connective tissue disorders. The majority, 64%, presented with symptoms including abdominal pain, back pain, and chest pain; the remaining 36% were asymptomatic. Combined SMA and CA dissection was found in 14 (18%) patients; 33 (43%) presented with isolated CA dissection, and 30 (39%) presented with isolated SMA dissection. Only four patients required intervention. Mesenteric bypass was performed in two patients, and SMA endarterectomy with patch angioplasty was performed in one patient for signs of bowel ischemia. No patient required bowel resection. The two bypasses were anastomosed to a branch of the SMA, and complete lumen restoration was seen on long-term imaging follow-up. One patient underwent stent grafting of the CA and hepatic artery for aneurysmal degeneration 1 month after diagnosis. The remaining 73 patients were managed nonoperatively; 40 (52%) were treated with a short course of anticoagulation, 23 (30%) were treated with antiplatelet therapy, and 10 (13%) were treated with observation alone. No other late interventions or recurrences were noted during a mean follow-up of 21 months.

CONCLUSIONS

Whereas isolated SMAD poses a risk of visceral ischemia, most patients presenting with this diagnosis can be treated nonoperatively with a short course of antiplatelet or anticoagulant therapy. Only a small number of patients require surgical revascularization for bowel ischemia.

Safety and Risk of Superselective Transcatheter Arterial Embolization for Acute Lower Gastrointestinal Hemorrhage with N-Butyl Cyanoacrylate: Angiographic and Colonoscopic Evaluation

PURPOSE

To retrospectively evaluate the safety and risk of transcatheter arterial embolization (TAE) with N-butyl cyanoacrylate (NBCA) for urgent acute arterial bleeding control in the lower gastrointestinal tract by angiography and colonoscopy.

MATERIALS AND METHODS

NBCA TAE was performed in 16 patients (mean age, 63.7 y) with lower gastrointestinal bleeding (diverticular hemorrhage, tumor bleeding, and intestinal tuberculosis). Angiographic evaluation was performed by counting the vasa recta filled with casts of NBCA and ethiodized oil (Lipiodol) after TAE. Patients were classified as follows: group Ia, with a single vas rectum with embolization of 1 branch (n = 6); group Ib, with a single vas rectum with embolization of ≥ 2 branches (n = 8); group II, with embolization of multiple vasa recta (n = 2). All patients underwent colonoscopy within 1 month, and ischemic complications (ulcer, scar, mucosal swelling, fibrinopurulent debris, and necrosis) were evaluated.

RESULTS

The procedure was successful in all patients. No ischemic change was observed in any patients in group Ia and in two patients in group Ib. Ischemic changes were observed in six group Ib patients and both group II patients. Group Ib patients experienced ischemic complications that improved without treatment. One patient in group II underwent resection for intestinal perforation after embolization of three vasa recta. One patient in group II with sigmoid stricture with embolization of six vasa recta required prolonged hospitalization.

CONCLUSIONS

NBCA embolization of ≥ 3 vasa recta can induce ischemic bowel damage requiring treatment. NBCA TAE of one vas rectum with ≥ 2 branches could also induce ischemic complications. However, these were silent and self-limited.

Ischemic bowel disease in 2021

Ischemic bowel disease (ISBODI) includes colon ischemia, acute mesenteric ischemia (AMI) and chronic mesenteric ischemia (CMI). Epidemiologically, colon ischemia is the most common type followed by AMI and CMI. There are various risk factors for the development of ISBODI. Abdominal pain is the common presenting symptom of each type. High clinical suspicion is essential in ordering appropriate tests. Imaging studies and colonoscopy with biopsy are the main diagnostic tests. Treatment varies from conservative measures to surgical resection and revascularization. Involvement of multidisciplinary team is essential in managing ISBODI. Although open surgery with revascularization plays an important role, recently there is an increasing interest in percutaneous endovascular treatment.

Non-occlusive mesenteric ischemia: Diagnostic challenges and perspectives in the era of artificial intelligence

Acute mesenteric ischemia (AMI) is a severe condition associated with poor prognosis, ultimately leading to death due to multiorgan failure. Several mechanisms may lead to AMI, and non-occlusive mesenteric ischemia (NOMI) represents a particular form of AMI. NOMI is prevalent in intensive care units in critically ill patients. In NOMI management, promptness and accuracy of diagnosis are paramount to achieve decisive treatment, but the last decades have been marked by failure to improve NOMI prognosis, due to lack of tools to detect this condition. While real-life diagnostic management relies on a combination of physical examination, several biomarkers, imaging, and endoscopy to detect the possibility of several grades of NOMI, research studies only focus on a few elements at a time. In the era of artificial intelligence (AI), which can aggregate thousands of variables in complex longitudinal models, the prospect of achieving accurate diagnosis through machine-learning-based algorithms may be sought. In the following work, we bring you a state-of-the-art literature review regarding NOMI, its presentation, its mechanics, and the pitfalls of routine work-up diagnostic exams including biomarkers, imaging, and endoscopy, we raise the perspectives of new biomarker exams, and finally we discuss what AI may add to the field, after summarizing what this technique encompasses.

Acute Mesenteric Ischemia: A Challenge for the Acute Care Surgeon

Acute mesenteric ischemia is considered uncommon, but it appears to be more frequent cause of acute abdomen than appendicitis or ruptured abdominal aortic aneurysm in elderly patients. Surgical treatment without revascularization is associated with high overall mortality, up to 80%. The modern treatment of acute mesenteric ischemia requires collaboration of gastrointestinal surgeons, vascular surgeons, and interventional radiologists. Early revascularization may reduce the overall mortality associated with acute mesenteric ischemia by up to 50%. Clinical suspicion and contrast-enhanced computed tomography performed at early stage are keys to improve outcomes of acute mesenteric ischemia treatment. This review summarizes what the acute care surgeon needs to know about acute mesenteric ischemia with special emphasis on slowly progressing "acute on chronic" mesenteric ischemia.

Reperfusion in non-occlusive mesenteric ischaemia (NOMI): effectiveness of CT in an emergency setting

OBJECTIVE

To investigate the CT features of reperfusion (presence/absence) in non-occlusive mesenteric ischaemia (NOMI) and their prognostic value in an emergency setting.

METHODS

A revision was undertaken of imaging from 20 patients (16 males/4 females) with a dismissal summary of NOMI. All patients had previously undergone a minimum of one multidetector CT examination, and consequently underwent surgery (n = 8), autopsy (n = 2), angiography (n = 1) or endoscopy (n = 9). An evaluation of the CT scans was conducted to determine vessels, mesentery, bowel and peritoneal cavity features. The superior mesenteric artery (SMA) average diameter of NOMI cases were compared with 30 controlled cases. Kappa, Kolmogorov-Smirnov (K-S) and Fisher's exact tests were used for statistical analysis.

RESULTS

A mean SMA diameter significantly smaller than that of the controlled cases was found for patients with NOMI (K-S test: D = 0.75, p = 3.7 × 10-08). Fisher's exact tests showed a strong connection between the presence of reperfusion and mesenteric fat stranding (p = 0.026), bowel wall thickening (p = 3.2 × 10-05) and a high attenuation of the bowel wall on unenhanced CT images (p = 2.8 × 10-04). A reduction in mortality was significantly linked to the combination of normal mesenteric vessels and wall thickening (p = 0.034).

CONCLUSION

Analysis of not only vessels findings but also mesentery and bowel CT features will support the identification of NOMI with or without a reperfusion event in an emergency setting. A strong correlation between some CT features and lower mortality exists.

ADVANCES IN KNOWLEDGE

CT features of NOMI with or without reperfusion are demonstrated. Correctly assessing the presence of reperfusion in NOMI, may allow better management of these conditions in the emergency setting.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

An investigation of bedside laparoscopy in the ICU for cases of non-occlusive mesenteric ischemia

BACKGROUND

Acute mesenteric ischemia is a rare affection with high related mortality. NOMI presents the most important diagnostic problems and is related with the higher risk of white laparotomy. This study wants to give a contribution for the validation of laparoscopic approach in case of NOMI.

METHODS

Thirty-two consecutive patients were admitted in last 10 years in ICU of Paolo Giaccone University Hospital of Palermo for AMI. Diagnosis was obtained by multislice CT and selective angiography was done if clinical conditions were permissive. If necrosis was already present or suspected, surgical approach was done. Endovascular or surgical embolectomy was performed when necessary. Twenty NOMI patients underwent medical treatment performing laparoscopy 24 h later to verify the evolution of AMI. A three-port technique was used. In all patients we performed a bed side procedure 48-72 h later in both non-resected and resected group.

RESULTS

In 14 up 20 case of NOMI the disease was extended throughout the splanchnic district, in 6 patients it involved the ileum and the colon; after a first look, only 6 patients underwent resection. One patient died 35 h after diagnosis of NOMI. The second look, 48 h later, demonstrated 4 infarction recurrences in the group of resected patients and onset signs of necrosis in 5 patients of non-resected group. A total of 15 resections were performed on 11 patients. Mortality rate was 6/20-30% but it was much higher in resected group (5/11-45,5%). Non-therapeutic laparotomy was avoided in 9/20 patients and in this group mortality rate was 1/9-11%. No morbidity was recorded related to laparoscopic procedure.

CONCLUSIONS

Laparoscopy could be a feasible and safety surgical approach for management of patient with NOMI. Our retrospective study demonstrates that laparoscopy don't increase morbidity, reduce mortality avoiding non-therapeutic laparotomy.

Discrimination between arterial and venous bowel ischemia by computer-assisted analysis of the fluorescent signal

BACKGROUND

Arterial blood supply deficiency and venous congestion both play a role in anastomotic complications. Our aim was to evaluate a software-based analysis of the fluorescence signal to recognize the patterns of bowel ischemia.

METHODS

In 18 pigs, two clips were applied on the inferior mesenteric artery (group A: n = 6) or vein (group V: n = 6) or on both (group A-V: n = 6). Three regions of interest (ROIs) were identified on the sigmoid: P = proximal to the first clip; C = central, between the two clips; and D = distal to the second clip. Indocyanine Green was injected intravenously. The fluorescence signal was captured by means of a near-infrared laparoscope. The time-to-peak (seconds) and the maximum fluorescence intensity were recorded using software. A normalized fluorescence intensity unit (NFIU: 0-to-1) was attributed, using a reference card. The NFIU's over-time variations were computed every 10 min for 50 min. Capillary lactates were measured on the sigmoid at the 3 ROIs. Various machine learning algorithms were applied for ischemia patterns recognition.

RESULTS

The time-to-peak at the ischemic ROI C was significantly longer in group A versus V (20.1 ± 13 vs. 8.43 ± 3.7; p = 0.04) and in group A-V versus V (20.71 ± 11.6 vs. 8.43 ± 3.7; p = 0.03). The maximal NIFU at ROI C, was higher in the V group (1.01 ± 0.21) when compared to A (0.61 ± 0.11; p = 0.002) and A-V (0.41 ± 0.2; p = 0.0005). Capillary lactates at ROI C were lower in V (1.3 ± 0.6) than in A (1.9 ± 0.5; p = 0.0071), and A-V (2.6 ± 1.5; p = 0.034). The K nearest neighbor and the Linear SVM algorithms provided both an accuracy of 75% in discriminating between A versus V and 85% in discriminating A versus A-V. The accuracy dropped to 70% when the ML had to identify the ROI and the type of ischemia simultaneously.

CONCLUSIONS

The computer-assisted dynamic analysis of the fluorescence signal enables the discrimination between different bowel ischemia models.

CT angiography in the setting of suspected acute mesenteric ischemia: prevalence of ischemic and alternative diagnoses

PURPOSE

The purpose of the study was to determine the prevalence of ischemic and alternative diagnoses and the diagnostic accuracy of CT angiography (CTA) in the setting of suspected acute mesenteric ischemia (AMI).

MATERIAL AND METHODS

We included 959 patients undergoing CTA for the evaluation of suspected AMI. The final clinical diagnosis was used to determine the prevalence of ischemic and alternative diagnoses and to calculate the diagnostic accuracy of CTA. Prevalence of diagnoses by age, sex, and admission status was compared using Cochran-Armitage and χ ² tests.

RESULTS

Prevalence was 18.8% (180/959) for AMI and 61.2% (587/959) for specific alternative diagnoses. In the remaining 20.0% (192/959), no clear clinical diagnosis was established. The most frequent alternative diagnoses were small-bowel obstruction (10.4%; 61/587), infectious colitis (8.7%; 51/587), pneumonia (6.5%; 38/587), cholecystitis (6.1%; 36/587), and diverticulitis (5.6%; 33/587). Prevalence of specific alternative diagnoses varied significantly according to both age (p < .013) and admissions status (p < 0.001). CTA had a sensitivity and specificity for diagnosing AMI of 89.4%/99.5% and for alternative diagnoses of 86.7%/96.9%, respectively.

CONCLUSION

In the setting of suspected AMI, the prevalence of ischemic and alternative diagnoses varies significantly by age, sex, and admission status. CTA provides for rapid and non-invasive assessment of ischemic and alternative diagnoses with high diagnostic accuracy.

Postoperative Catheter-Directed Thrombolysis Versus Systemic Anticoagulation for Acute Superior Mesenteric Venous Thrombosis

BACKGROUND

Little data evaluate catheter-directed thrombolysis (CDT) therapy as a sequential treatment of emergent surgery for patients with acute superior mesenteric venous thrombosis (ASMVT). We compared the outcomes of ASMVT patients receiving CDT via superior mesenteric artery (SMA) with those who had systemic anticoagulation after emergent laparotomy.

METHODS

A single-center retrospective study of ASMVT patients receiving emergent laparotomy from May 2012 to April 2014 was performed. Patients in group I had postoperative systemic anticoagulation and patients in group II underwent postoperative CDT. The demography, etiology, imaging features, clinical outcomes, and complications were compared. Moreover, univariate analysis was performed to identify confounding variables of 30-day mortality.

RESULTS

Thirty-two patients (20 males, mean age of 44.9 ± 10.6 years) were included, 17 in group I and 15 in group II. No significant differences of demographic data, etiology, baseline value, and perioperative comorbidity were found. The rate of complete thrombus removal was significantly higher in group II than group I (29.4% vs. 80.0%, P = 0.001). The second-look laparotomy and repeat bowel resection (58.8% vs. 13.3%, P = 0.002) were required in fewer patients in group II (20.0% vs. 70.6%, P = 0.001). The incidence of short-bowel syndrome (SBS; 41.2% vs. 6.7%, P = 0.001) and 30-day mortality (41.2% vs. 6.7%, P = 0.001) were lower in group II. The 1-year survival was also better in group II (52.9% vs. 93.3%, P = 0.014). The incidence of massive abdominal hemorrhage requiring blood transfusion and surgical intervention was 11.8% in group I and 20.0% in group II (P = 0.645). The age, serum D-dimer level, SBS, and postoperative CDT were significant risk factors of 30-day mortality in this study.

CONCLUSIONS

For ASMVT patients receiving emergent surgery and intraoperative thrombectomy, the algorithm with postoperative CDT via SMA is associated with more favorable clinical outcome compared with systemic anticoagulation.

Predictors of transmural intestinal necrosis in patients presenting with acute mesenteric ischemia on computed tomography

PURPOSE

The purpose of this study was to identify the significant imaging predictors of transmural intestinal necrosis in patients with acute mesenteric ischemia (AMI).

METHODS

The medical records and CT imaging of 48 patients between 2011 and 2019 suspected of having AMI that underwent exploratory laparotomy with bowel resection and pathological confirmation of ischemic bowel injury were retrospectively reviewed. Using histopathology as a gold standard, various parameters related to vascular insufficiency and bowel injury were analyzed and correlated with outcome of ischemic bowel necrosis using nonparametric tests. Univariate analysis was performed using Fisher's exact test followed by binary logistic regression test for multivariate analysis.

RESULTS

48 Patients (19 females, 40%) with a median age of 68.5 years (IQR of 17 years) built our retrospective cohort. 26 (54%) patients were found to have transmural intestinal necrosis on histopathology (case group) whereas 22 (46%) patients had partial mucosal injury (control group). Pneumatosis intestinalis (p = 0.005, odd's ratio of 2.07-63.14) and severity (> 70% or complete occlusion) of vascular narrowing (p = 0.019, odd's ratio of 1.39-42.30) were identified as the most significant predictors of transmural ischemic necrosis on imaging. Dilatation of bowel did not approach the statistical significance on multivariate analysis although it was found significant on univariate analysis (p = 0.041).

CONCLUSION

Pneumatosis intestinalis and severity of vascular luminal narrowing are the most important imaging predictors of transmural ischemic bowel necrosis in patients presenting with AMI. The presence of these findings on CT scan should raise high index of suspicion for irreversible transmural ischemic necrosis. In the absence of these factors, endovascular management might be beneficial.

Endovascular revascularization of acute arterial mesenteric ischemia: report of a 3-year experience from an intestinal stroke center unit

OBJECTIVE

To report the 3-year experience of endovascular revascularization of acute arterial mesenteric ischemia (AMI) from an intestinal stroke center unit (ISCU).

METHOD

All data from patients admitted to the ISCU between January 2016 and January 2019 for arterial AMI who underwent endovascular recanalization were prospectively acquired and retrospectively analyzed. Patient demographics, clinical and laboratory characteristics at presentation, and CT scans were reviewed. The type (thrombolysis, thrombectomy, stenting) and the outcome of endovascular procedures (technical success or failure, complications) were noted. Care pathways were described focusing on post-procedural treatments (surgical revascularization, bowel resection) and the mortality rate was evaluated in subgroups.

RESULTS

Fifty-eight patients (34 men [59%], mean 69 ± 29 years) were included. Endovascular revascularization was technically successful in 51/58 (88%) patients, and 10 (17%) patients had post-procedural complications. Stenting and in situ thrombolysis were performed in most patients (n = 33 and n = 19, respectively). Thirty-two patients (55%) were recurrence-free and required no further treatment after the procedure, while 9 (16%), 5 (9%), and 5 (9%) patients underwent 2nd-line bowel resection, surgical revascularization, or both. Overall, 46 (79%), 45 (78%), and 34 patients (63%) were alive at 3 months, 1 year, and 3 years. No significant difference in survival was found in care pathways or baseline characteristics.

CONCLUSION

Endovascular revascularization is highly feasible for the treatment of arterial AMI, and is associated with an acceptable rate of complications. Results of endovascular revascularization shall only be interpreted as part of a multidisciplinary patient management strategy.

KEY POINTS

• Endovascular revascularization is highly feasible for the treatment of arterial AMI, and is associated with an acceptable rate of complications. • Several techniques are available to perform endovascular revascularization, and their use depends on the cause, the location, and the quality of underlying arteries of patients. • Results of endovascular revascularization shall only be interpreted in relation to its role in an integrated multidisciplinary and patient management strategy.

The role of multislice computed tomography (MSCT) angiography in the diagnosis and therapy of non-occlusive mesenteric ischemia (NOMI): Could MSCT replace DSA in diagnosis?

Objectives

Evaluation of multislice-CT (MSCT) during diagnosis and therapeutic decision-making in patients with suspected non-occlusive mesenteric ischemia (NOMI).

Methods

Retrospective, institutional review board-approved study of 30 patients (20 men, 10 women, mean age 64.6±14.2 years, range 24–87 years) undergoing biphasic abdominal MSCT followed by digital subtraction angiography (DSA) due to suspected NOMI. MSCT and DSA were qualitatively and quantitatively evaluated independently by two radiologists with respect to the possible diagnosis of NOMI. MSCT analysis included quantitative measurements, qualitative evaluation of contrast enhancement and assessment of secondary findings (bowel wall thickening, hypo-enhancement, intestinal pneumatosis). MSCT diagnosis and secondary findings were compared against DSA diagnosis.

Results

NOMI was diagnosed in a total of n = 28 patients. No differences were found when comparing the R1-rated MSCT diagnosis (p = 0.09) to the “gold standard”, while MSCT diagnosis was slightly inferior with R2 (p = 0.02). With R1, vessel-associated parameters revealed the best correlation, i.e. qualitative vessel width (r = -0.39;p = 0.03) and vessel contrast (r = 0.45;p = 0.01). Moderate correlations were found for quantitative vessel diameters in the middle segments (r = -0.48,p = 0.01), increasing to almost high correlations in the distal (r = -0.66;p<0.00001) superior mesenteric artery (SMA) segments. No significant correlation was apparent from secondary findings.

Conclusions

MSCT is an appropriate non-invasive method for diagnosing NOMI and leads to adequate and immediate therapeutic stratification.

ACR Appropriateness Criteria® Radiologic Management of Mesenteric Ischemia

Mesenteric vascular insufficiency is a serious medical condition that may lead to bowel infarction, morbidity, and mortality that may approach 50%. Recommended therapy for acute mesenteric ischemia includes aspiration embolectomy, transcatheter thrombolysis, and angioplasty with or without stenting for the treatment of underlying arterial stenosis. Nonocclusive mesenteric ischemia may respond to transarterial infusion of vasodilators such as nitroglycerin, papaverine, glucagon, and prostaglandin E1. Recommended therapy for chronic mesenteric ischemia includes angioplasty with or without stent placement and, if an endovascular approach is not possible, surgical bypass or endarterectomy. The diagnosis of median arcuate ligament syndrome is controversial, but surgical release may be appropriate depending on the clinical situation. Venous mesenteric ischemia may respond to systemic anticoagulation alone. Transhepatic or transjugular superior mesenteric vein catheterization and thrombolytic infusion can be offered depending on the severity of symptoms, condition of the patient, and response to systemic anticoagulation. Adjunct transjugular intrahepatic portosystemic shunt creation can be considered for outflow improvement. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

A clinical approach to acute mesenteric ischemia

PURPOSE OF REVIEW

To summarize current evidence on acute mesenteric ischemia (AMI) in critically ill patients, addressing pathophysiology, definition, diagnosis and management.

RECENT FINDINGS

A few recent studies showed that a multidiscipliary approach in specialized centers can improve the outcome of AMI. Such approach incorporates current knowledge in pathophysiology, early diagnosis with triphasic computed tomography (CT)-angiography, immediate endovascular or surgical restoration of mesenteric perfusion, and damage control surgery if transmural bowel infarction is present. No specific biomarkers are available to detect early mucosal injury in clinical setting. Nonocclusive mesenteric ischemia presents particular challenges, as the diagnosis based on CT-findings as well as vascular management is more difficult; some recent evidence suggests a possible role of potentially treatable stenosis of superior mesenteric artery and beneficial effect of vasodilator therapy (intravenous or local intra-arterial). Medical management of AMI is supportive, including aiming of euvolemia and balanced systemic oxygen demand/delivery. Enteral nutrition should be withheld during ongoing ischemia-reperfusion injury and be started at low rate after revascularization of the (remaining) bowel is convincingly achieved.

SUMMARY

Clinical suspicion leading to tri-phasic CT-angiography is a mainstay for diagnosis. Diagnosis of nonocclusive mesenteric ischemia and early intestinal injury remains challenging. Multidisciplinary team effort may improve the outcome of AMI.

Radiological predictive factors of transmural intestinal necrosis in acute mesenteric ischemia: systematic review and meta-analysis

OBJECTIVE

Transmural intestinal necrosis (TIN) is related to high mortality in patients with acute mesenteric ischemia (AMI). Radiological predictive factors of TIN in AMI remains controversial. This study aimed to identify the CT-based predictive factors of TIN in AMI.

METHODS

EMBASE and PUBMED were searched for publications predicting TIN using radiological features. Quality Assessment of Diagnostic Accuracy Studies-2 was used to assess the methodological quality of individual studies. Data were presented in terms of diagnostic odds ratio (DOR), sensitivity, specificity, and 95% confidence interval (CI). The random-effects models were used for the meta-analysis.

RESULTS

Eleven studies including 1037 cases with AMI were considered. The meta-analysis showed that bowel wall thinning (DOR = 13.10; 95% CI: 3.71, 46.25), decreased or absent bowel wall enhancement (DOR = 5.77; 95% CI: 2.95, 11.30), bowel dilation (DOR = 3.23; 95% CI: 2.03, 5.15), pneumatosis intestinalis (DOR = 5.78; 95% CI: 2.24, 14.95), porto-mesenteric venous gas (DOR = 5.36; 95% CI: 2.14, 13.40), and arterial occlusive AMI (DOR = 2.66; 95% CI: 1.53, 4.63) were risk factors for predicting TIN. Bowel wall thinning and porto-mesenteric venous gas displayed high specificity to diagnose TIN (98%, 95%, respectively). The subgroup analysis showed that decreased or absent bowel wall enhancement (DOR = 8.23; 95% CI: 4.67, 14.51) and bowel dilation (DOR = 3.14; 95% CI: 1.55, 6.39) were predictors of TIN in venous occlusive AMI, which were not related to TIN in arterial-origin AMI.

CONCLUSIONS

For predicting TIN, there are specific radiological features. The radiological predictors of TIN may differ according to the various causes of AMI. Future primary studies should further evaluate the relationships between radiological signs and TIN based on different etiologies.

KEY POINTS

• Bowel wall thinning, decreased or absent bowel wall enhancement, bowel dilation, pneumatosis intestinalis, porto-mesenteric venous gas, and arterial occlusive AMI were risk factors for predicting TIN. • Decreased or absent bowel wall enhancement and bowel dilation were predictors of TIN in venous occlusive AMI, which were not related to TIN in arterial-origin AMI.

Midterm results after covered stenting of the superior mesenteric artery

OBJECTIVE

Despite the continuing controversy of covered stents (CS) vs bare metal stents, the use of CS in mesenteric occlusive disease (MOD) has been recommended by expert centers. The aim of this study was to report midterm results with CS of the superior mesenteric artery.

METHODS

Between January 2014 and October 2019, patients with MOD with a severe atheromatous stenosis or occlusion of the superior mesenteric artery treated by mesenteric CS were included. Clinical presentation included both acute mesenteric ischemia (AMI), chronic mesenteric ischemia, and asymptomatic patients planned for major surgery. Demographics, procedure details, and follow-up data were prospectively collected and retrospectively reviewed. Study end points included primary patency, primary assisted patency, and secondary patency.

RESULTS

During the study period, 86 patients (mean age, 70 ± 9 years; 57% males) were included. Clinical presentation was AMI (n = 42 [49%]), chronic mesenteric ischemia (n = 31 [36%]), and asymptomatic (n = 13 [15%]). The technical success rate was 97%. A total of 96 stents were implanted, including 86 proximal CS (Advanta V12, n = 73; Lifestream, n = 13). The mean length and mean diameter of the CS were 31.5 ± 6.3 mm and 6.9 ± 0.5 mm, respectively. Additional distal bare metal stents were used in 10 patients (12%) to overcome a kinking (n = 9) or a dissection (n = 1) downstream of the CS. All postoperative deaths occurred in patients with AMI (n = 11, 13%). During a median follow-up of 15.6 months (95% confidence interval [CI], 15.6 ± 3.6 months), 12 patients (14%) underwent reinterventions for either stent misplacement (n = 3), stent recoil (n = 3), stent thrombosis (n = 2), de novo stenosis at the distal edge of the CS (n = 2), or gastric ischemia (n = 1). At 1 year, overall the primary patency, primary assisted patency, and secondary patency rates were 83% (95% CI, 83% ± 9%), 99% (95% CI, 99% ± 3%), and 99% (95% CI, 99% ± 3%), respectively. At 2 years, the overall primary patency, primary assisted patency, and secondary patency rates were 76% (95% CI, 76% ± 13%), 95% (95% CI, 95% ± 8%) and 95% (95% CI, 95% ± 8%), respectively.

CONCLUSIONS

Mesenteric CS provide very satisfactory midterm results in patients with MOD, with an excellent primary assisted patency rate at 2 years, at the price of a significant reintervention rate.

Acute superior mesenteric venous thrombosis results in high rates of readmission and morbidity

OBJECTIVE

Superior mesenteric venous thrombosis (MVT) is a poorly understood clinical entity, and as such, outcomes are poorly described. This study aimed to identify predictors of bowel ischemia after MVT and to compare outcomes for patients treated medically (group 1) with those for patients treated with bowel resection (group 2).

METHODS

This was a retrospective, single-institution study capturing all patients diagnosed with symptomatic acute MVT on computed tomography imaging from 2008 to 2018. Demographics, comorbidities, imaging, laboratory values, and treatment were included. Predictors of bowel resection were analyzed by univariate and multivariate statistics. Outcomes including mortality, readmissions for abdominal pain, and chronic mesenteric venous congestion were compared using χ² test.

RESULTS

There were 121 patients included in the study; 98 patients were treated medically (group 1), 19 patients were treated with bowel resection (group 2), and 4 patients were treated with endovascular recanalization (group 3). Group 1 and group 2 were compared directly. Patients requiring bowel resection tended to have higher body mass index (P = .051) and a hypercoagulable disorder (P = .003). Patients who required bowel resection were more likely to present with lactic acidosis (P < .001) and leukocytosis (P < .001) with bowel wall thickening on scan (P < .001). On multivariable analysis, a genetic thrombophilia was a strong predictor of bowel ischemia (odds ratio, 3.81; 95% confidence interval, 1.12-12.37). One-year mortality and readmission rates did not differ between groups. However, readmission rates for abdominal pain were high for both groups (group 1, 44.90%; group 2, 57.89%; P = .317), and a significant proportion of patients exhibited chronic mesenteric venous congestion on repeated scan (group 1, 42.86%; group 2, 47.37%; P = .104).

CONCLUSIONS

A genetic hypercoagulable disorder is a predictor of bowel ischemia due to MVT. Regardless of treatment, outcomes after MVT are morbid, with high rates of readmission for abdominal pain. An alternative approach to treat these patients is needed, given the poor outcomes with current strategies.

Normal Lactate and Unenhanced CT-Scan Result in Delayed Diagnosis of Acute Mesenteric Ischemia

INTRODUCTION

To investigate the factors associated with a delayed diagnosis (DD) of acute mesenteric ischemia (AMI).

METHODS

An observational cohort study from an intestinal failure center. The primary outcome was DD >24 hours.

RESULTS

Between 2006 and 2015, 74 patients with AMI were included and 39 (53%) had a DD. Plasma lactate <2 mmol/L (odd ratio: 3.2; 95% confidence interval: 1.1-9.1; P = 0.03) and unenhanced computed tomography scan (odds ratio: 5.9; 95% confidence interval: 1.4-25.8; P = 0.01) were independently associated with DD.

DISCUSSION

Suspicion of AMI should no longer be affected by normal plasma lactate levels and should prompt evaluation by a contrast-enhanced computed tomography-scan.

Clinical Features and Factors Affecting Postoperative Mortality for Obstructive Acute Mesenteric Ischemia in China: A Hospital- Based Survey

PURPOSE

The study aimed to report the clinical manifestation and identify the risk factors for postoperative mortality in patients who were diagnosed with obstructive acute mesenteric ischemia (AMI) based on a survey of a hospital in western China.

PATIENTS AND METHODS

We reviewed clinical data of 108 patients with obstructive AMI at West China Hospital, Sichuan University, from 2011 to 2017. Clinical characteristic was described and compared. Factors affecting postoperative survival were analyzed.

RESULTS

A total of 108 obstructive AMI cases were included in this study, with an overall average age of 57.1 years, including 58 arterial occlusive mesenteric ischemia (AOMI) and 50 mesenteric venous thrombosis (MVT). AOMI patients were older and had a significantly higher frequency of these comorbidities, including heart disease, hypertension, and diabetes. In comparison, MVT had a significantly higher proportion of male patients and a higher frequency of liver disease. A total of 77 patients underwent laparotomy, and the 30-day postoperative mortality rate was 29.9%. Multivariate logistic regression analysis showed that the time interval from admission to surgery (adjust OR 1.19; 95% CI [1.07-1.34], P = 0.005), platelet count (adjust OR = 0.98; 95% CI [0.97-0.99], P = 0.008) and AOMI (adjust OR = 5.55; 95% CI [1.36-22.55], P = 0.017) were independent predictors of 30-day mortality after exploratory laparotomy for obstructive AMI. Further analysis of the 45 AOMI showed that the time interval from admission to surgery (adjustOR 1.22; 95% CI [1.01-1.47], P = 0.036) and platelet count (adjustOR = 0.98; 95% CI [0.97-0.99], P = 0.020) were independent risk factors for 30-day postoperative mortality of AOMI.

CONCLUSION

Early identification of AOMI, improving the efficiency of enhanced CT examination, strengthening doctor-patient communication, active laparotomy, and optimize platelet management may also help reduce the overall short-term mortality of obstructive AMI. Building the multidisciplinary team model of diagnostic imaging, vascular intervention, and surgical treatment to manage obstructive AMI may be urgently needed in western China.