Evaluation of acute mesenteric ischemia: accuracy of biphasic mesenteric multi-detector CT angiography

Comparison of Endovascular Therapy and Open Surgical Revascularization in Patients With Acute Superior Mesenteric Artery Occlusion: A Large-Scale Analysis Based on the JROAD-DPC Database

BACKGROUND

Acute mesenteric ischemia is rare, and few large-scale trials have evaluated endovascular therapy (EVT) and open surgical revascularization (OS). This study aimed to assess clinical outcomes after EVT or OS for acute superior mesenteric artery occlusion and identify predictors of mortality and bowel resection.

METHODS AND RESULTS

Data from the Japanese Registry of All Cardiac and Vascular Diseases-Diagnosis Procedure Combination (JROAD-DPC) database from April 2012 to March 2020 were retrospectively analyzed. Overall, 746 patients with acute superior mesenteric artery occlusion who underwent revascularization were classified into 2 groups: EVT (n=475) or OS (n=271). The primary clinical outcome was in-hospital mortality. The secondary outcomes were bowel resection, bleeding complications (transfusion or endoscopic hemostasis), major adverse cardiovascular events, hospitalization duration, and cost. The in-hospital death or bowel resection rate was ≈30%. In-hospital mortality (22.5% versus 21.4%, P=0.72), bowel resection (8.2% versus 8.5%, P=0.90), and major adverse cardiovascular events (11.6% versus 9.2%, P=0.32) were comparable between the EVT and OS groups. Hospitalization duration in the EVT group was 6 days shorter than that in the OS group, and total hospitalization cost was 0.88 million yen lower. Interaction analyses revealed that EVT and OS had no significant difference in terms of in-hospital death in patients with thromboembolic and atherothrombotic characteristics. Advanced age, decreased activities of daily living, chronic kidney disease, and old myocardial infarction were significant predictive factors for in-hospital mortality. Diabetes was a predictor of bowel resection after revascularization.

CONCLUSIONS

EVT was comparable to OS in terms of clinical outcomes in patients with acute superior mesenteric artery occlusion. Some predictive factors for mortality or bowel resection were obtained.

REGISTRATION

URL: www.umin.ac.jp/ctr/; Unique Identifier: UMIN000045240.

Late-onset non-obstructive mesenteric ischemia (NOMI) resulting from delayed absorption of overdosed antihypertensive drugs: An autopsy case report

Non-obstructive mesenteric ischemia (NOMI) is caused by reduced blood flow to the intestines without physical occlusion in the mesenteric artery. Previous reports show that drug overdose occasionally induces late-onset NOMI; however, in most cases, the reason for the delayed onset is unclear. Here, we present an autopsy case of late-onset NOMI that was induced by a drug overdose. An 80-year-old man was admitted to the intensive care unit because of severe hypotension after an overdose of antihypertensive drugs. He received vasopressor therapy and continuous hemodiafiltration dialysis; however, gastrointestinal decontamination was not performed. He began to recover but developed acute mesenteric ischemia on the evening of day 4 and died on day 5. Autopsy showed discontinuous submucosal bleeding from the duodenum to the colon; there was no thrombus in the mesenteric artery, which led to a diagnosis of NOMI. In the stomach, there was 250 mL of reddish-brown fluid with a muddy brown substance. Histologic examination revealed ischemic necrosis in the small intestine. Quantitative analysis of serum collected during hospitalization revealed that nifedipine and cilostazol levels had peaked on day 3 of hospitalization. The formulation of nifedipine was a controlled-release tablet, and the low water solubility of cilostazol may have caused the tablets to adhere and remain in the stomach. Therefore, the drugs had been released into the blood stream several days after hospitalization, leading to delayed-onset NOMI. In cases of overdose, it is crucial to consider the formulation and properties of the involved drugs when determining medical treatment.

Outcome of laparotomy and conservative treatment of patients with acute mesenteric venous ischemia with viable bowel

BACKGROUND

Acute mesenteric ischemia (AMI) is one of the most serious abdominal emergencies. Predicting the onset of bowel necrosis that warrants surgical intervention is of paramount importance in AMI. The present study aimed to investigate the outcome of patients with AMI secondary to mesenteric venous occlusion (MVO) and the consequence of non-therapeutic exploratory laparotomy.

METHODS

The records of 132 patients with AMI were retrospectively reviewed. The outcome of patients with acute mesenteric venous ischemia (AMVI) and viable bowel was analyzed based on the method of treatment: conservative versus surgical. The impact of non-therapeutic laparotomy on the outcome of patients with AMVI in terms of morbidity, readmission, and mortality was analyzed.

RESULTS

Forty-seven patients (34 male) with AMVI had viable bowel. Of the 47 patients with viable bowel, 8 (17%) had an exploratory non-therapeutic laparotomy, whereas 39 patients were treated conservatively. Patients who had non-therapeutic laparotomy had significantly higher complication (50 vs 5.1%, p = 0.005) and readmission rates (37.5 vs 5.1%, p = 0.03) and longer hospital stay (8.5 vs 7 days, p = 0.02) than those treated conservatively. Patients with bowel necrosis who had a therapeutic laparotomy had slightly lower rates of morbidity and mortality as compared to patients with viable bowel who underwent a non-therapeutic laparotomy.

CONCLUSION

Careful assessment and informed decision-making in patients with AMVI are crucial to avoid unnecessary surgical intervention that can result in higher rates of complications and readmission and extended hospital stay.

Treatment of acute mesenteric ischemia between 2010 and 2020 - a German nation-wide study

BACKGROUND

Aim of this study was to analyze long-term trends of hospitalizations, treatment regimen and in-hospital mortality of in-patients with acute mesenteric ischemia (AMI) over the past decade and effects of the SARS-CoV2-pandemic.

METHODS

We analyzed fully anonymized data from the German Federal Statistical Office of patients with AMI between 2010 and 2020. Besides descriptive analyses of age, gender, in-hospital mortality, comorbidity burden and treatment regimen, multivariable logistic regression analyses were performed to identify independent variables associated with in-hospital mortality and different treatment.

RESULTS

A total of 278,121 hospitalizations (120,667 male [43.4%], mean age 72.1 years) with AMI were included in this study. The total number of hospitalizations increased from 2010 (n = 24,172) to 2019 (n = 26,684) (relative increase 10.4%). In-hospital mortality decreased over the past decade from 36.6% to 2010 to 31.1% in 2019 (rel. decrease 15.2%). Independent risk factors for in-hospital mortality were older age (OR = 1.03 per year), higher comorbidity burden (OR = 1.06 per point in van Walraven score [vWs]), male gender (OR = 1.07), AMI as a secondary diagnosis (OR = 1.44), and the need for surgical (visceral surgery: OR = 1.38, vascular surgery: OR = 3.33) and endovascular treatment (OR = 1.21). We report a decline in hospitalizations during the first wave of infection in spring 2020 (rel. decrease 9.7%).

CONCLUSION

In-hospital mortality rate has declined over the past decade, but remains high at above 30%. Older age, increased comorbidity and male gender are independent factors for in-hospital mortality. Hospitalizations requiring vascular surgery are associated with high in-hospital mortality, followed by visceral surgery and endovascular approaches. The first wave of the SARS-CoV2-pandemic in spring 2020 implied a decrease in hospital admissions.

Results after intraoperative open and endovascular revascularization of acute mesenteric ischemia requiring a laparotomy

BACKGROUND

Acute mesenteric ischemia (AMI) is a dreaded condition with a difficult diagnosis and high mortality. Due to different baseline situations, the frequently performed comparison between endovascular and open surgical treatment is interfered with selection bias. The purpose of this study was to review outcomes in AMI treatment with an open or endovascular approach in association with laparotomy and to evaluate the endovascular-first strategy in similar clinical situations.

METHODS

The clinical data of 74 patients treated for AMI from 2007 to 2021 were retrospectively reviewed and compared. In-hospital mortality was appointed as the primary study endpoint. Risk factors for mortality were identified by using univariate and multivariate analysis.

RESULTS

In total, 61 patients (82%) were treated open surgically (OT) and, 13 patients (18%) with an endovascular approach (ET) in combination with laparatomy. The etiology of AMI was 49% arteriosclerotic and 51% thromboembolic occlusions. The total in-hospital mortality manifested at 43% (n =32) (OT 41% vs. ET 53.8%; P=0.54). As independent risk factors for in-hospital mortality, pneumatosis intestinalis (P=0.01), increased lactate concentration (P=0.04), and ischemic intestinal sections (P=0.01) were identified. Additionally, on univariate analysis patient age, congestive heart failure (> NYHA II) and atrial fibrillation were related with higher mortality.

CONCLUSIONS

Morbidity and mortality of AMI remains at a high level. Conventional open or intraoperative endovascular therapy achieved similar results in patients with indication for laparotomy. Advanced disease stage with ischemic intestinal sections at presentation and cardiovascular comorbidities were associated with adverse outcome.

Hypercoagulability status, operative mortality, and long-term survival in patients operated on for mesenteric venous thrombosis

OBJECTIVE

Mesenteric venous thrombosis (MVT) is a rare cause of acute surgical abdomen, with high mortality. The aim of this study was to analyze long-term outcomes and possible factors influencing its prognosis.

METHODS

All patients who underwent urgent surgery for MVT from 1990 to 2020 in our center were reviewed. Epidemiological, clinical, and surgical data; postoperative outcomes; origin of thrombosis; and long-term survival were analyzed. Patients were divided into two groups: primary MVT (hypercoagulability disorders or idiopathic MVT) and secondary MVT (underlying disease).

RESULTS

Fifty-five patients, 36 (65.5%) men and 19 (34.5%) women, mean age 66.7 years (standard deviation: ±18.0 years), underwent surgery for MVT. Arterial hypertension (63.6%) was the most prevalent comorbidity. Regarding the possible origin of MVT, 41 (74.5%) patients had primary MVT and 14 (25.5%) patients had secondary MVT. From these, 11 (20%) patients had hypercoagulable states, 7 (12.7%) had neoplasia, 4 (7.3%) had abdominal infection, 3 (5.5%) had liver cirrhosis, 1 (1.8%) patient had recurrent pulmonary thromboembolism, and 1 (1.8%) had deep venous thrombosis. Computed tomography was diagnostic of MVT in 87.9% of the cases. Intestinal resection was performed in 45 patients due to ischemia. Only 6 patients (10.9%) had no complication, 17 patients (30.9%) presented minor complications, and 32 patients (58.2%) presented severe complications according to the Clavien-Dindo classification. Operative mortality was 23.6%. In univariate analysis, comorbidity measured by the Charlson index (P = .019) and massive ischemia (P = .002) were related to operative mortality. The probability of being alive at 1, 3, and 5 years was 66.4%, 57.9%, and 51.0%, respectively. In univariate analysis of survival, age (P < .001), comorbidity (P < .001), and type of MVT (P = .003) were associated with a good prognosis. Age (P = .002; hazard ratio: 1.05, 95% confidence interval: 1.02-1.09) and comorbidity (P = .019; hazard ratio: 1.28, 95% confidence interval: 1.04-1.57) behaved as independent prognostic factors for survival.

CONCLUSIONS

Surgical MVT continues to show high lethality. Age and comorbidity according to the Charlson index correlate well with mortality risk. Primary MVT tends to have a better prognosis than secondary MVT.

Risk factors for postoperative disseminated intravascular coagulation in surgical patients with non-occlusive mesenteric ischemia

PURPOSE

The prognostic impact of disseminated intravascular coagulation (DIC) in surgical patients with non-occlusive mesenteric ischemia (NOMI) is unclear. This study aimed to confirm the association between postoperative DIC and prognosis and to identify preoperative risk factors associated with postoperative DIC.

METHODS

This retrospective study included 52 patients who underwent emergency surgery for NOMI between January 2012 and March 2022. Kaplan-Meier curve analysis with the log-rank test was used to compare 30-day survival and hospital survival between patients with and without postoperative DIC. In addition, univariable and multivariable logistic regression analyses were performed to identify the preoperative risk factors for postoperative DIC.

RESULTS

The 30-day and hospital mortality rates were 30.8% and 36.5%, respectively, and the incidence rate of DIC was 51.9%. Compared to patients without DIC, patients with DIC showed significantly lower rates of 30-day survival (41.5% vs 96%, log-rank P < 0.001) and hospital survival (30.2% vs 86.4%, log-rank, P < 0.001). Logistic regression analyses showed that the Japanese Association for Acute Medicine (JAAM) DIC score (OR = 2.697; 95% CI, 1.408-5.169; P = 0.003) and Sequential Organ Failure Assessment (SOFA) score (OR = 1.511; 95% CI, 1.111-2.055; P = 0.009) were independent risk factors for postoperative DIC in surgical patients with NOMI.

CONCLUSION

The development of postoperative DIC is a significant prognostic factor for 30-day and hospital mortalities in surgical patients with NOMI. In addition, the JAAM DIC score and SOFA score have a high discriminative ability for predicting the development of postoperative DIC.

Management of acute mesenteric ischaemia: Results of a worldwide survey

BACKGROUND

Acute mesenteric ischaemia (AMI) is a condition with high mortality. This survey assesses current attitudes and practices to manage AMI worldwide.

METHODS

A questionnaire survey about the practices of diagnosing and managing AMI, endorsed by several specialist societies, was sent to different medical specialists and hospitals worldwide. Data from individual health care professionals and from medical teams were collected.

RESULTS

We collected 493 individual forms from 71 countries and 94 team forms from 34 countries. Almost half of respondents were surgeons, and most of the responding teams (70%) were led by surgeons. Most of the respondents indicated that diagnosis of AMI is often delayed but rarely missed. Emergency revascularisation is often considered for patients with AMI but rarely in cases of transmural ischaemia (intestinal infarction). Responses from team hospitals with a dedicated special unit (14 team forms) indicated more aggressive revascularisation. Abdominopelvic CT-scan with intravenous contrast was suggested as the most useful diagnostic test, indicated by approximately 90% of respondents. Medical history and risk factors were thought to be more important in diagnosis of AMI without transmural ischaemia, whereas for intestinal infarction, plasma lactate concentrations and surgical exploration were considered more useful. In elderly patients, a palliative approach is often chosen over extensive bowel resection. There was a large variability in anticoagulant treatment, as well as in timing of surgery to restore bowel continuity.

CONCLUSIONS

Delayed diagnosis of AMI is common despite wide availability of an adequate imaging modality, i.e. CT-scan. Large variability in treatment approaches exists, indicating the need for updated guidelines. Increased awareness and knowledge of AMI may improve current practice until more robust evidence becomes available. Adherence to the existing guidelines may help in improving differences in treatment and outcomes.

An Update on Acute Mesenteric Ischemia

Acute mesenteric ischemia (AMI) is an uncommon yet highly lethal cause of acute abdomen in the emergency setting. Computed tomography (CT) imaging, in particular a biphasic protocol consisting of angiographic and venous phase scans, is widely used to corroborate non-specific clinical findings when suspicions of AMI are high. Techniques such as low kilovoltage peak scanning, dual energy acquisition, or a combined arterial/enteric phase can improve iodine conspicuity and evaluation of bowel enhancement. Biphasic CT with CT angiography is mandatory to directly assess for the 3 primary etiologies of AMI-arterial, venous, and non-occlusive mesenteric ischemia (NOMI), and the CT angiographic findings may be the first visible in the disease. In addition, numerous non-vascular CT findings have also been reported. Bowel wall thickening, mesenteric stranding, and ascites are common but non-specific findings that correlate poorly with disease severity. Pneumatosis intestinalis and portomesenteric venous gas, while not pathognomonic for ischemia, are highly specific in cases of high clinical suspicion. Bowel wall hypoenhancement is an early and specific sign but requires a protocol optimizing iodine conspicuity to confidently identify. Finally, intraperitoneal free air and solid organ infarcts are also highly specific ancillary findings in AMI. AMI occurs as a complication in 10% of small bowel obstruction (SBO) patients, and understanding imaging findings of ischemia in the context of SBO is necessary to aid in treatment planning and reduce over- and under-diagnosis of strangulation. Familiarity with the imaging features of ischemia by radiologists is vital to establish an early diagnosis before irreversible necrosis occurs.

Epidemiology of Acute Mesenteric Ischemia: A Population-Based Investigation

BACKGROUND

There is a lack of population-based studies on acute mesenteric ischemia (AMI). We have therefore performed a nationwide epidemiological study in Estonia, addressing incidence, demographics, interventions and mortality of AMI.

METHODS

A retrospective population-based review was conducted of all adult cases of AMI accrued from the digital Estonian Health Insurance Fund and Causes of Death Registry for 2016-2020 based on international classification of diseases (ICD-10) diagnostic codes and procedure codes (NOMESCO).

RESULTS

Overall, 577 cases of AMI were identified-an annual incidence of 8.7 per 100,000. The median age was 79 (range 32-104) and 57% were female. Predominating comorbidities included hypertensive disease (81%), atherosclerosis (67%), and atrial fibrillation (52%). The majority of cases (60%) were caused by superior mesenteric artery occlusion (thrombosis 54%, embolism 12%, and unclear 34%). Inferior mesenteric artery occlusion occurred in 7%, non-occlusive mesenteric ischemia in 7%, venous thrombosis in 4%, whereas the type remained unclear in 21% of cases. 40% of patients received intervention (revascularization and/or intestinal resection) and 13% active non-operative treatment. In 21% an exploratory laparotomy or laparoscopy revealed unsalvageable bowel prompting end-of-life care, which was the only management in a further 25% of cases.

CONCLUSIONS

The population-based annual incidence of AMI in Estonia was 8.7 per 100,000 during the study period. The overall hospital mortality and 1 year mortality were 64% and 74%, respectively. In the 53% of patients who received active treatment hospital mortality was 32% and 1 year all-cause mortality was 51%.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT04867499.

Acute mesenteric ischemia: updated guidelines of the World Society of Emergency Surgery

Acute mesenteric ischemia (AMI) is a group of diseases characterized by an interruption of the blood supply to varying portions of the intestine, leading to ischemia and secondary inflammatory changes. If untreated, this process may progress to life-threatening intestinal necrosis. The incidence is low, estimated at 0.09-0.2% of all acute surgical admissions, but increases with age. Although the entity is an uncommon cause of abdominal pain, diligence is required because if untreated, mortality remains in the range of 50%. Early diagnosis and timely surgical intervention are the cornerstones of modern treatment to reduce the high mortality associated with this entity. The advent of endovascular approaches in parallel with modern imaging techniques is evolving and provides new treatment options. Lastly, a focused multidisciplinary approach based on early diagnosis and individualized treatment is essential. Thus, we believe that updated guidelines from World Society of Emergency Surgery are warranted, in order to provide the most recent and practical recommendations for diagnosis and treatment of AMI.

Preoperative findings on non-specific CT in patients with primary acute intestinal ischemia: a case-control study

PURPOSE

Primary acute intestinal ischaemia (AII) is an abdominal catastrophe caused by intravascular obstruction of blood supply. It is difficult to diagnose. Computerized tomography (CT) scan is the modality of choice for diagnostic evaluation. Majority of previous studies have evaluated CT findings in patients where AII was suspected. However, unveiling the unique radiological findings also in not initially suspected AII patients, might lead to the timely management of AII patients, and is the aim of this study.

METHODS

In a single-center, retrospective case-control study, preoperative radiological findings from abdominal CT scans in 48 patients with primary AII were compared with 80 non-ischemic controls. Radiological findings were analyzed using multivariable logistical regression with adjustment for age and gender and reported as odds ratios (OR) with 95% confidence intervals (CI) and p values.

RESULTS

Thirty-nine (81%) cases with AII were referred to an abdominal CT scan without a specific clinical suspicion of AII. Three main radiological categories (intestinal wall pathology [OR 7.4, CI 2.3-24.0, p value < 0.001], gastrointestinal vessel pathology [OR 19.3, CI 4.6-80.5, p value < 0.001) and intestinal diameter [OR 4.7, CI 1.6-13.4, p value 0.004]) were significantly different in AII patients. Subgroup analysis implied that pneumatosis intestinalis, increased contrast enhancement in the bowel wall, inferior mesenteric artery arteriosclerosis and colonic contraction were predictors of AII.

CONCLUSION

Radiological changes within the intestinal wall, luminal diameter and gastrointestinal vessels are independent predictors of AII. Awareness of these radiological findings, therefore, plays a central role in patients with an indistinct clinical picture in early recognition and treatment of a life-threatening AII.

TRIAL REGISTRATION NUMBER

NCT04361110 (April 24, 2020), retrospectively registered.

Two cases of intestinal perforation due to mesenteric artery embolism during extracorporeal membrane oxygenation and intra-aortic balloon pumping

The patient in case 1 was a 50-year-old man who presented to the emergency department of the local hospital with chest pain and syncope for 3 hours due to acute myocardial infarction. He underwent cardiopulmonary resuscitation (CPR) followed by extracorporeal membrane oxygenation (ECMO), and intestinal perforation was detected on day 9. The patient in case 2 was a 58-year-old man who was admitted to the hospital with abdominal pain lasting for 3 days. He also required CPR and ECMO for cardiogenic shock, and intestinal perforation was identified on day 7 of ECMO. We believe that this case report will be important to alert clinicians to the possibility of this complication and to encourage early detection and intervention to improve prognosis. Conventionally, the gastrointestinal tract has received secondary attention in patients receiving ECMO support because the vital organs tend to be considered first. However, this case report illustrates the importance of monitoring gastrointestinal function in patients undergoing ECMO.

Dual-energy CT of acute bowel ischemia

Acute bowel ischemia is a condition with high mortality and requires rapid intervention to avoid catastrophic outcomes. Swift and accurate imaging diagnosis is essential because clinical findings are commonly nonspecific. Conventional contrast enhanced CT of the abdomen has been the imaging modality of choice to evaluate suspected acute bowel ischemia. However, subtlety of image findings and lack of non-contrast or arterial phase images can make correct diagnosis challenging. Dual-energy CT provides valuable information toward assessing bowel ischemia. Dual-energy CT exploits the differential X-ray attenuation at two different photon energy levels to characterize the composition of tissues and reveal the presence or absence of faint intravenous iodinated contrast to improve reader confidence in detecting subtle bowel wall enhancement. With the same underlying technique, virtual non-contrast images can help to show non-enhancing hyperdense hemorrhage of the bowel wall in intravenous contrast-enhanced scans without the need to acquire actual non-contrast scans. Dual-energy CT derived low photon energy (keV) virtual monoenergetic images emphasize iodine contrast and provide CT angiography-like images from portal venous phase scans to better evaluate abdominal arterial patency. In Summary, dual-energy CT aids diagnosing acute bowel ischemia in multiple ways, including improving visualization of the bowel wall and mesenteric vasculature, revealing intramural hemorrhage in contrast enhanced scans, or possibly reducing intravenous contrast dose.

Recurrent Acute Pancreatitis and Superior Mesenteric Venous Thrombosis - Cause or Course

The management of pancreatitis can be daunting, especially when associated with other comorbidities. These complexities in management are conflicting in the presence of comorbidities with a similar presentation, such as abdominal pain. Acute pancreatitis (AP) has been associated with mesenteric thrombosis but less commonly with superior mesenteric vein thrombosis (SMVT) as a causal or complicating dilemma. This case report describes the careful intrigues and overlaps in presentation. Furthermore, this paper presents a dilemma in that contrast-enhanced computed tomography (CT) may not be recommended in the early stage of diagnosis of AP according to the 2013 American College of Gastroenterology (ACG) guideline, but SMVT, which can be fatal, sometimes, complicates AP, and contrast-enhanced CT is important in its diagnosis. This paper attempts to address this dilemma. Managing these two potentially fatal pathologies requires promptness and thoughtfulness in averting a deadly outcome. Because SMVT is fatal, in this paper, we reiterate the use of contrast-enhanced CT in the early stages of the management of AP. Fatal complications from AP should not be missed. Although contrast-enhanced CT is not recommended in the early stages of diagnosis of AP in the ACG guideline, fatal complications such as SMVT can be avoided.

Many faces of acute bowel ischemia: overview of radiologic staging

Acute bowel ischemia (ABI) can be life threatening with high mortality rate. In spite of the advances made in diagnosis and treatment of ABI, no significant change has occurred in the mortality over the past decade. ABI is potentially reversible with prompt diagnosis. The radiologist plays a central role in the initial diagnosis and preventing progression to irreversible intestinal ischemic injury or bowel necrosis. The most single imaging findings described in the literature are either non-specific or only present in the late stages of ABI, urging the use of a constellation of features to reach a more confident diagnosis. While ABI has been traditionally categorized based on the etiology with a wide spectrum of imaging findings overlapped with each other, the final decision for patient’s management is usually made on the stage of the ABI with respect to the underlying pathophysiology. In this review, we first discuss the pathologic stages of ischemia and then summarize the various imaging signs and causes of ABI. We also emphasize on the correlation of imaging findings and pathological staging of the disease. Finally, a management approach is proposed using combined clinical and radiological findings to determine whether the patient may benefit from surgery or not.

Pearls, Pitfalls, and Conditions that Mimic Mesenteric Ischemia at CT

Acute mesenteric ischemia (AMI) is a life-threatening condition with a high mortality rate. The diagnosis of AMI is challenging because patient symptoms and laboratory test results are often nonspecific. A high degree of clinical and radiologic suspicion is required for accurate and timely diagnosis. CT angiography of the abdomen and pelvis is the first-line imaging test for suspected AMI and should be expedited. A systematic "inside-out" approach to interpreting CT angiographic images, beginning with the bowel lumen and proceeding outward to the bowel wall, mesentery, vasculature, and extraintestinal viscera, provides radiologists with a practical framework to improve detection and synthesis of imaging findings. The subtypes of AMI are arterial and venoocclusive disease, nonocclusive ischemia, and strangulating bowel obstruction; each may demonstrate specific imaging findings. Chronic mesenteric ischemia is more insidious at onset and almost always secondary to atherosclerosis. Potential pitfalls in the diagnosis of AMI include mistaking pneumatosis as a sign that is specific for AMI and not an imaging finding, misinterpretation of adynamic ileus as a benign finding, and pseudopneumatosis. Several enterocolitides can mimic AMI at CT angiography, such as inflammatory bowel disease, infections, angioedema, and radiation-induced enterocolitis. Awareness of pitfalls, conditions that mimic AMI, and potential distinguishing clinical and imaging features can assist radiologists in making an early and accurate diagnosis of AMI. ^©RSNA, 2020.

A pilot study investigating the use of 4D flow MRI for the assessment of splanchnic flow in patients suspected of mesenteric ischaemia

The most common cause of chronic mesenteric ischaemia is atherosclerosis which results in limitation of blood flow to the gastrointestinal tract. This pilot study aimed to evaluate 4D flow MRI as a potential tool for the analysis of blood flow changes post-prandial within the mesenteric vessels. The mesenteric vessels of twelve people were scanned; patients and healthy volunteers. A baseline MRI scan was performed after 6 h of fasting followed by a post-meal scan. Two 4D flow datasets were acquired, over the superior mesenteric artery (SMA) and the main portal venous vessels. Standard 2D time-resolved PC-MRI slices were also obtained across the aorta above the coeliac trunk, superior mesenteric vein, splenic vein and portal vein (PV). In the volunteer cohort there was a marked increase in blood flow post-meal within the PV (p = 0.028), not seen in the patient cohort (p = 0.116). Similarly, there were significant flow changes within the SMA of volunteers (p = 0.028) but not for the patient group (p = 0.116). Our pilot data has shown that there is a significant haemodynamic response to meal challenge in the PV and SMA in normal subjects compared to clinically apparent CMI patients. Therefore, the interrogation of mesenteric venous vessels exclusively is a feasible method to measure post-prandial flow changes in CMI patients.

Influence of clinical suspicion on CT accuracy of acute mesenteric ischemia: Retrospective study of 362 patients

PURPOSE

Acute mesenteric ischemia (AMI) may be underdiagnosed when not clinically suspected before CT is performed. We assessed the influence of a clinical suspicion of AMI on the CT accuracy.

METHOD

This retrospective single-centre study included patients who underwent CT in 2014-2019 and had clinically suspected AMI and/or confirmed AMI. CT protocols were adapted based on each patient's presentation and on findings from unenhanced images. The CT protocol was considered optimal for AMI when it included arterial and portal venous phases. CT protocols, accuracy of reports, and outcomes were compared between the groups with and without suspected AMI before CT.

RESULTS

Of the 375 events, 337 (90 %) were suspected AMI and 66 (18 %) were AMI, including 28 (42 %) with and 38 without suspected AMI. These two groups did not differ significantly regarding the medical history, clinical presentation, or laboratory tests. The CT protocol was more often optimal for AMI in the group with suspected AMI (26/28 [93 %] vs. 28/38 [74 %], p = 0.046). Diagnostic accuracy was not different between groups with and without suspected AMI (26/28 [93 %] vs. 34/38 [90 %], p = 1.00). However, it was lower in the group without suspicion of AMI when the CT protocol was not optimal for AMI (27/28 [96 %] vs 7/10 [70 %], p = 0.048).

CONCLUSIONS

The negative influence of not clinically suspecting AMI can be mitigated by using a tailored CT protocol.

Acute Mesenteric Infarction: The Chameleon of Acute Abdomen Evaluating the Quality of the Diagnostic Parameters in Acute Mesenteric Ischemia

INTRODUCTION/OBJECTIVE

Acute mesenteric ischemia (AMI) is difficult to diagnose. Since the established parameters have low sensitivity and specificity, the aim of this study is to analyze the diagnostic quality of the established parameters of AMI.

METHODS

All patients that underwent emergency surgery due to suspected diagnosis of mesenteric ischemia at the University Medical Center Hamburg-Eppendorf between 2008 and 2014 were evaluated. Overall, 275 patients were enrolled and pre-, intra- and postoperative data were evaluated.

RESULTS

In 200 patients, a mesenteric ischemia was confirmed intraoperatively, and 75 patients had no ischemia. Comparing these groups, the rate of patients with pH < 7.2 (25 vs. 12%; p = 0.021) and elevated mean CRP level (175 ± 117 mg/L vs. 139 ± 104 mg/L; p = 0.019) was significantly higher in ischemic patients. There was no significant difference in the level of preoperative lactate. Concerning abdominal CT scan, a sensitivity and specificity of 61 and 68%, respectively, was found.

CONCLUSION

New diagnostic parameters are needed. So far, explorative laparotomy is the only reliable diagnostic method to detect mesenteric infarction.

[Is acute mesenteric ischemia incurable situation? The current state of the problem]

Mortality rates in acute mesenteric ischemia remain at an extremely high level for many decades. Early diagnosis and selection of the optimal method of revascularization are among the ways to optimize tactics. The diagnostic study of choice is CT angiography. Its active and systemic use can help to detect ischemia at the reversible stage. The article examines in detail the indications for the application of this diagnostic study. The question of preference for the revascularization method remains debatable. The arguments of proponents of open and endovascular interventions on mesenteric vessels are presented. Other, still unresolved tactical issues are also considered, such as indications for re-operations and application of the principles of damage control tactics.

Risk factors of geriatrics index of comorbidity and MDCT findings for predicting mortality in patients with acute mesenteric ischemia due to superior mesenteric artery thromboembolism

OBJECTIVES

To identify risk factors of geriatrics index of comorbidity (GIC) and multidetector CT (MDCT) findings for predicting mortality in patients with acute mesenteric ischemia (AMI) due to superior mesenteric artery (SMA) thromboembolism.

METHODS

33 patients with AMI due to SMA thromboembolism underwent abdominal MDCT and angiography. Patients' comorbidities and MDCT findings of ischemic bowel/mesenteric injuries, regions of SMA involved by thromboembolism, and degrees of SMA stenosis were retrospectively reviewed. The comorbidities were classified into 1-4 levels according to GIC. The association of MDCT signs and GIC classification with mortality were analyzed. Diagnostic performances of risk factors associated with mortality were evaluated by receiver operating characteristic (ROC) curve analyses.

RESULTS

Eighteen patients (54.5%) died during hospitalization or follow-up, including one patient with class 1, two patients with class 2, eight patients with class 3, and seven patients with class 4 according to GIC. Three risk factors significantly associated with mortality were identified, including pneumatosis and/or portomesenteric venous gas (PPMVG) (p = 0.017), four regions of SMA involved by thromboembolism (region I + II + III + IV) (p = 0.036), and class 3 + 4 of comorbidities (p = 0.001). The sensitivity and specificity of PPMVG, region I + II + III + IV, class 3 + 4 of comorbidities, and the three risk factors combined for diagnosing mortality were 33.3 and 100%, 27.8 and 100%, 83.3 and 73.3%, and 88.9 and 73.3%, respectively. The areas under the ROC curve (AUC) of the three risk factors combined (0.88) and class 3 + 4 of comorbidities (0.78) were larger than that of PPMVG (0.67) and region I + II + III + IV (0.64). The mortality rate rose from 15.4% in patients without risk factor to 66.7%, 100%, and 100% in patients with one, two, and three factors, respectively.

CONCLUSION

Three risk factors for mortality were identified in patients with AMI due to SMA thromboembolism, including PPMVG and four regions of SMA involved by thromboembolism on MDCT images, and class 3 + 4 of comorbidities. Close monitoring of these risk factors could possibly lower the mortality.

ADVANCES IN KNOWLEDGE

Risk factors based on GIC and MDCT findings may be used to predict mortality in patients with AMI. Close monitoring of these risk factors could possibly lower the mortality.

Acute Mesenteric Ischemia

Background

Despite constant improvements in diagnostic as well as interventional and surgical techniques, acute mesenteric ischemia (AMI) remains a life-threatening emergency with high mortality rates. The time to diagnosis of AMI is the most important predictor of patients' outcome; therefore, prompt diagnosis and intervention are essential to reduce mortality in patients with AMI. The present review was performed to analyze potential risk factors and to help find ways to improve the outcome of patients with AMI.

Summary

Whereas AMI only applies to approximately 1% of all patients with an "acute abdomen," its incidence is rising up to 10% in patients >70 years of age. The initial clinical stage of AMI is characterized by a sudden onset of strong abdominal pain followed by a painless interval. Depending on the extent of disease, the symptoms of nonocclusive mesenteric ischemia (NOMI) and patients with a venous thrombosis can be very different from those of acute occlusive ischemia. Biphasic contrast-enhanced CT represents the gold standard for the diagnosis of arterial and venous occlusion. In case of a central occlusion of the superior mesenteric artery or signs of peritonitis, immediate surgery should be performed. If major bowel resection becomes necessary, critical residual intestinal length limits must be kept in mind. Endovascular techniques for arterial occlusion have taken on a much greater importance today. For stable patients with NOMI, interventional catheter angiography is recommended because it enables diagnosis and treatment with selective application of vasodilators. Depending on its degree, interventional treatment with a transhepatic catheter lysis should be considered for acute and chronic portal vein thrombosis.

Key Message

The prompt and targeted use of the appropriate diagnostics and interventions appears to be the only way to reduce the persistently high mortality rates for AMI.

Predictors of irreversible intestinal resection in patients with acute mesenteric venous thrombosis

BACKGROUND

Acute mesenteric venous thrombosis (AMVT) can cause a poor prognosis. Prompt transcatheter thrombolysis (TT) can achieve early mesenteric revascularization. However, irreversible intestinal ischemia still occurs and the mechanism is still unclear.

AIM

To evaluate the clinical outcomes of and to identify predictive factors for irreversible intestinal ischemia requiring surgical resection in AMVT patients treated by TT.

METHODS

The records of consecutive patients with AMVT treated by TT from January 2010 to October 2017 were retrospectively analyzed. We compared patients who required resection of irreversible intestinal ischemia to patients who did not require.

RESULTS

Among 58 patients, prompt TT was carried out 28.5 h after admission. A total of 42 (72.4%) patients underwent arteriovenous combined thrombolysis, and 16 (27.6%) underwent arterial thrombolysis alone. The overall 30-d mortality rate was 8.6%. Irreversible intestinal ischemia was indicated in 32 (55.2%) patients, who had a higher 30-d mortality and a longer in-hospital stay than patients without resection. The significant independent predictors of irreversible intestinal ischemia were Acute Physiology and Chronic Health Evaluation (APACHE) II score (odds ratio = 2.368, 95% confidence interval: 1.047-5.357, P = 0.038) and leukocytosis (odds ratio = 2.058, 95% confidence interval: 1.085-3.903, P = 0.027). Using the receiver operating characteristic curve, the cutoff values of the APACHE II score and leukocytosis for predicting the onset of irreversible intestinal ischemia were calculated to be 8.5 and 12 × 10⁹/L, respectively.

CONCLUSION

Prompt TT could achieve a favorable outcome in AMVT patients. High APACHE II score and leukocytosis can significantly predict the occurrence of irreversible intestinal ischemia. Therefore, close monitoring of these factors may help with the early identification of patients with irreversible intestinal ischemia, in whom ultimately surgical resection is required, before the initiation of TT.

Comparison of diagnostic accuracy for nonocclusive mesenteric ischemia in models with biomarkers including intestinal fatty acid-binding protein in addition to clinical findings

BACKGROUND

Nonocclusive mesenteric ischemia (NOMI) is an acute and life-threatening gastrointestinal disorder, requiring rapid therapeutic intervention for ischemic bowel. However, its rapid detection remains challenging. This retrospective, observational study was aimed at comparing the diagnostic accuracy for NOMI in models of biomarkers, including intestinal fatty acid-binding protein (I-FABP), and clinical findings.

METHODS

All consecutive patients who presented to the emergency department of the study hospital with suspected NOMI were prospectively enrolled. Receiver operating characteristic analysis compared the diagnostic accuracy of I-FABP with traditional biomarkers (white blood cell count, C-reactive protein, lactate, creatine kinase, and D-dimer) alone and in combination with the baseline model established from clinical findings.

RESULTS

Of 96 patients with suspected NOMI, 25 (26.0%) were clinically diagnosed with NOMI. In-hospital mortality was higher in patients with NOMI than those with other conditions (56.0% vs. 4.2%, p < 0.001). Receiver operating characteristic analyses revealed that the I-FABP model had the highest area under the curve (0.805) in the diagnosis of NOMI, compared with other biomarkers. The diagnostic model of clinical findings including age, cardiovascular disease history, undergoing hemodialysis, hypotension, and consciousness disturbance in combination with I-FABP showed the best discrimination (area under the curve, 0.883), compared with other biomarkers. The bootstrap optimism estimate showed the lowest discrimination among the other models with other biomarkers (0.006).

CONCLUSION

The usefulness of I-FABP for final diagnosis of NOMI in patients with clinically suspected NOMI at the emergency department was internally validated. Further external validation study is warranted.

LEVEL OF EVIDENCE

Diagnostic test, level III.

Contrast-Enhanced CT for the Diagnosis of Acute Mesenteric Ischemia

OBJECTIVE. The purpose of this article is to provide an overview of the diagnostic and prognostic roles of CT in the management of acute mesenteric ischemia. CONCLUSION. Acute mesenteric ischemia is defined as inadequate blood supply to the gastrointestinal tract resulting in ischemic and inflammatory injury. The prognosis is poor without treatment. Contrast-enhanced CT has become the cornerstone of diagnosis to identify features of vascular disorders and of intestinal ischemic injury and to visualize bowel necrosis.

Non-occlusive Mesenteric Ischemia as a Fatal Complication in Acute Pancreatitis: A Case Series

BACKGROUND

Vascular complications of severe acute pancreatitis are well known and largely described unlike non-occlusive mesenteric ischemia, which is a rare and potentially fatal complication. Non-occlusive mesenteric ischemia is an acute mesenteric ischemia without thrombotic occlusion of blood vessels, poorly described as a complication of acute pancreatitis.

METHODS

We retrospectively reviewed a prospectively maintained registry of all pancreatic diseases referred to our center from 2013 to 2018, in order to determine the causes of early death. We identified three patients who died within 48 h after hospital admission from severe acute pancreatitis complicated by irreversible non-occlusive mesenteric ischemia. Their clinical presentation, management, and outcomes were herein reported.

RESULTS

Three consecutive patients with severe acute pancreatitis developed non-occlusive mesenteric ischemia within the first 5 days after onset of symptoms and died 48 h after non-occlusive mesenteric ischemia diagnosis despite optimal intensive care management and surgery, giving a prevalence of 3/609 (0.5%). Symptoms were unspecific with consequently potential delayed diagnosis and management. High doses of norepinephrine required for hemodynamic support (n = 3) potentially leading to splanchnic vessels vasoconstriction, transient hypotension (n = 3), and previous severe ischemic cardiomyopathy (n = 1) could be involved as precipitating factors of non-occlusive mesenteric ischemia.

CONCLUSION

Non-occlusive mesenteric ischemia can be a fatal complication of acute pancreatitis but is also challenging to diagnose. Priority is to reestablish a splanchno-mesenteric perfusion flow. Surgery should be offered in case of treatment failure or deterioration but is still under debate in early stage, to interrupt the vicious circle of intestinal hypoperfusion and ischemia.

Acute mesenteric ischemia (AMI): absence of renal insufficiency and performance of early bowel resection may indicate improved outcomes

PURPOSE

Acute mesenteric ischemia (AMI) is still associated with very high morbidity and mortality while the rareness and heterogeneity hamper the establishment of evidence-based guidelines. We sought to help standardize contemporary treatment by a cohort study at our tertiary center in the rising endovascular age.

METHODS

A retrospective cohort study was conducted from 2005 to 2015. Patients with occlusive (OMI), non-occlusive (NOMI), and venous mesenteric ischemia (VMI) were compared with respect to clinical and treatment parameters as well as outcome.

RESULTS

The study cohort consisted of 48 patients composed of 27 males and 21 females with an average age of 63 years and an average BMI of 25.1 kg/m². In 48% of patients (N=23), an acute arterial OMI had occurred while NOMI was present in 31% (N=15) and VMI in 21% (N=10). Interventional and intraoperative recanalizations were significantly more often required in OMI patients compared with other entities (p=0.003). Patients with venous mesenteric ischemia had a significant better overall survival than patients with OMI or NOMI in the univariate analysis (p=0.027). Patients with renal failure had a 14.7-fold higher relative risk (Cox p=0.013) and patients without bowel resection during primary surgery had a 17.8-fold higher relative risk (Cox p=0.047) to die of AMI in the postoperative course.

CONCLUSIONS

AMI remains a rare but oftentimes fatal disease. Our study provides evidence that outcome may depend on the AMI subtype, presence of renal insufficiency, and early bowel resection. Further research should help individualize treatment for optimized outcomes.

Necessity of revascularization for acute mesenteric ischemia in symptomatic patients with spontaneous isolated dissection of the superior mesenteric artery

Objectives

We evaluated the necessity of revascularization for acute mesenteric ischemia in symptomatic patients with spontaneous isolated dissection of the superior mesenteric artery.

Methods

This retrospective study included 28 consecutive, symptomatic patients with spontaneous isolated dissection of the superior mesenteric artery treated at our hospital between December 2005 and December 2017. Patients with concomitant aortic dissection were excluded. We reviewed the patients’ clinical presentation; laboratory evaluations; computed tomography findings, including the true lumen residual ratio (i.e., the minimum true lumen size compared to the diameter of the transverse section of the dissected artery) at the time of admission; the number of patients who were suspected of having bowel ischemia; and the number of patients who required surgical or endovascular treatment and their outcomes. Additionally, to evaluate the true lumen residual ratio in symptomatic patients with bowel ischemia, the true lumen residual ratio in those with abnormal laboratory data were compared with that in those without abnormal laboratory data. Initial true lumen residual ratio values were also compared with final values. Furthermore, we assessed the clinical details of patients who had bowel necrosis. Categorical variables were compared using the χ2 test or Fisher’s exact test, and continuous values were presented as either the mean ± standard deviation or median (interquartile range 25–75%). Variables were analyzed using Student’s t-test or the Mann–Whitney U test.

Results

The patients’ age ranged between 41 and 85 years, and 25 were men. Although nine patients were suspected of having acute mesenteric ischemia, only one underwent bowel resection. None of the patients had an indication for revascularization. The true lumen residual ratio of the nine patients with abnormal laboratory data were significantly lower than those of the 19 without abnormal laboratory data (10 [0–25]% vs. 40 [20–50]%, p = 0.005). The patient who underwent bowel resection had a true lumen residual ratio of 10%; however, there was no obvious abnormal laboratory data suggestive of bowel necrosis. Dissections were managed conservatively in all patients. True lumen residual ratio increased from initial value of 30 (10–48)% to 98 (60-100)%at the final imaging study ( p < 0.0001). There were no adverse events related to the mesenteric circulation during the follow-up period of 2–11 years.

Conclusions

Reintervention is rarely required for spontaneous isolated dissection of the superior mesenteric artery, even in symptomatic patients, and spontaneous resolution of the luminal compromise is the rule.

Mesenteric ischemia: what the radiologist needs to know

Acute mesenteric ischemia (AMI) is a life-threatening condition that often presents with abdominal pain. Early diagnosis with contrast-enhanced computed tomography and revascularization can reduce the overall mortality in AMI. This article reviews practical etiological classification, pathophysiology of imaging manifestations and common pitfalls in intestinal ischemia.

Review: Acute superior mesenteric artery embolism: A vascular emergency cannot be ignored by physicians

BACKGROUND

Acute mesenteric ischemia (AMI) is a life-threatening medical condition that occurs when a sudden decreased perfusion to the intestines which leads to bowel infarction, and acute superior mesenteric artery embolism (ASMAE) is the main cause of AMI. Unfortunately, with the improvement of diagnosis and treatment technology, the mortality remains high due to less frequent clinical suspicion resulted from the unclear clinical manifestation and non-specific laboratory findings.

METHODS

Relevant studies published were identified by searching the PubMed, Embase and Cochrane Library databases. This review presented the literatures to introduce the research progress of ASMAE in recent years.

RESULTS

Patients with the history of atrial fibrillation, heart valve disease and atherosclerosis should be considered as ASMAE. Laboratory findings are insensitive and unspecific, however, angiography and Computed tomography angiography (CTA) can provide a clear diagnosis sensitively and specifically. Endovascular approaches have been increasingly reported in multiple case series. The key to successful treatment of AMI involves early clinical recognition and early intervention to move the embolus, which can reduce the rate of misdiagnosis and save the precious time and lives of patients.

CONCLUSIONS

Loss of time eventually leads to progression of ischemia to transmural bowel necrosis with peritonitis and septicemia, which may further worsen patients' outcomes. It is important for physicians to make a timely and accurate diagnosis, which can save precious time and reduce the mortality.

Use of long saphenous vein graft in acute on chronic mesenteric ischaemia

Acute mesenteric ischaemia is a relatively rare surgical emergency, but despite advances in diagnostic tests, the mortality of this condition remains stubbornly high (50%-80%). This is principally because of the non-specific nature of the presenting symptoms and subsequent delay in diagnosis. We report an unusual case of acute mesenteric ischaemia treated by emergency laparotomy, small bowel resection and revascularisation using reversed long saphenous vein graft.

Acute Gut Ischemia

Acute mesenteric ischemia is a surgical emergency commonly caused by embolic or thrombotic occlusion of the superior mesenteric artery. Prompt diagnosis, fluid resuscitation, systemic anticoagulation, and mesenteric revascularization are key tenants to the treatment of this lethal condition. Revascularization can be performed via open thromboembolectomy or surgical bypass, endovascular techniques, or a hybrid approach of the 2. Despite technological advancements, mortalities remain high, and the plan of care and revascularization should be based on the patient's clinical status and available medical center resources.

The Ongoing Challenge of Acute Mesenteric Ischemia

Background

The lethality of acute mesenteric ischemia (AMI) remains quite high with 50-70%. The main reasons for that are the fact that AMI is rarely taken into consideration by the differential diagnosis of acute abdomen, the time-consuming diagnostic process, and the lack of a standardized therapeutic concept. The present interdisciplinary review aims to increase awareness among physicians and to help improve clinical outcomes.

Methods

This clinical therapeutic review is based on author expertise as well as a selective literature survey in PubMed based on the term 'mesenteric ischemia', combined with the terms 'arterial', 'clinical presentation', 'diagnosis', 'therapy', 'surgery', and 'interventional radiology'. Based on these search results as well as on the guidelines of the German Society of Vascular Surgery, the American College of Cardiology, and the American Heart Association, we present an interdisciplinary treatment concept.

Results

AMI is a vascular emergency that can be successfully treated only within the first hours after the onset of symptoms. Computed tomography angiography is the diagnostic method of choice. Intensive care unit treatment can prevent the occurrence of multiple organ failure. Treatment primarily consists of the revascularization of the mesenteric arteries. Endovascular techniques should be given priority, whereas signs of peritonitis or a central arterial occlusion with high thrombus load primarily require a surgical approach in order to save time and increase patient safety. Additional bowel resections can play a significant role in the treatment of intestinal sepsis.

Conclusion

Prompt and goal-oriented diagnosis and consistent treatment of AMI within 4-6 h from the onset of symptoms can be decisive for the reduction of AMI-associated lethality. In order for this to happen, a standardized concept of emergency treatment needs to be implemented.

Split-bolus single scan CTA for evaluation of mesenteric ischemia

PURPOSE

To evaluate split-bolus single scan CTA protocol for evaluation of acute mesenteric ischemia.

MATERIALS AND METHODS

In this HIPAA-compliant IRB-approved study, consecutive patients evaluated for mesenteric ischemia between 11/2015 and 10/2016 were included. Patients scanned prior to 4/2016 were scanned with multiphasic CTA protocol and after with split-bolus single scan CTA. Objective and subjective evaluation was performed by three board-certified readers. Findings were correlated to composite clinical reference outcome.

RESULTS

Eighty patients were included: 40 with split-bolus and 40 with multiphasic CTA protocol with similar age (60.3 ± 16.2 years vs. 64.7 ± 17.0 years, p = 0.19) and BMI (28.0 ± 6.7 vs. 27.0 ± 8.7, p = 0.56). SMA attenuation was higher in multiphasic protocol compared to split-bolus protocol (336.5 ± 97.5 HU vs. 258.0 ± 67.3 HU, p < 0.001) with similar SMV attenuation (multiphasic 213.7 ± 58.4 HU vs. split-bolus 194.2 ± 52.2 HU, p = 0.14). Optimal phase of bowel, liver, and spleen enhancement was seen in similar high proportion (94-99%) in both protocols. There were 8/40 (20%) positive cases of mesenteric ischemia in each group. There was no difference in the diagnostic confidence of the readers for evaluation of the mesenteric vessels and bowel ischemia. There were no missed cases of mesenteric ischemia in either group. Mean effective dose was 42% lower in the split-bolus group, p < 0.001. There was a higher number of axial images to review in multiphasic protocol compared to split-bolus protocol (437.9 ± 48.7 vs. 263.5 ± 31.2, p < 0.001).

CONCLUSIONS

The split-bolus protocol for evaluation of mesenteric ischemia is clinically feasible with confident and accurate diagnostic ability, while reducing number of images and decreasing radiation exposure to the patient.

The Role of Noncontrast CT in the Evaluation of Surgical Abdomen Patients

Acute surgical abdomen is commonly encountered in the ED and CT is widely used as an informative diagnostic tool to evaluate potential surgical indications. However, the adverse effects of contrast material used in CTscanning have been documented. We sought to delineate the role of noncontrast CT in the evaluation of patients with acute surgical abdomen. Between August 2015 and December 2015, patients with nontraumatic surgical abdomen who underwent preoperative CT were enrolled in the current study. The patients for whom the CT results permitted surgical decision-making were the focus of this study. The disease entities included acute appendicitis, acute cholecystitis, hollow organ perforation, mechanical bowel obstruction, intra-abdominal abscess that could not be drained percutaneously, and ischemic bowel disease. The results of contrast-enhanced and noncontrast CT were compared and analyzed. The surgical conditions identifiable by noncontrast CT were recorded. In total, 227 patients were enrolled in the study. In 90.7 per cent of patients overall, the findings indicating the need for surgical treatment were visualized on both the noncontrast and contrast-enhanced images (acute appendicitis: 89.3%, acute cholecystitis: 89.7%, hollow organ perforation: 97.4%, bowel obstruction: 100%, intra-abdominal abscess: 100%, and ischemic bowel disease: 55.6%). Noncontrast CT provides benefit for critical decision-making. Body mass index may affect the accuracy of noncontrast imaging in the evaluation of patients with surgical abdomen. In some specific situations, contrast enhancement remains necessary.

Treatment of nonocclusive mesenteric ischemia with type B aortic dissection using intra-arterial catheterization after trauma surgery: case report

Background

Nonocclusive mesenteric ischemia (NOMI) is a mesenteric arterial spasm and intestinal ischemia. This disease is a highly lethal disease because diagnosis and decision of appropriate treatments are often difficult. Operations cannot resolve the spasms and may worsen the situation. However, the safety and effectiveness of catheterization for NOMI with aortic dissection (AD) have not yet been elucidated. Here, we report a successful case of early diagnosis and treatment of NOMI with type B AD involving the superior mesenteric artery (SMA) using the intra-arterial infusion of a vasodilator via the SMA.

Case presentation

An 83-year-old man was admitted to our hospital because of abdominal pain after a motor accident. We performed intestinal resection and splenectomy for intestinal perforation and splenic hemorrhage and treated conservatively for acute AD, liver injury, renal hematoma, and pneumothorax. On postoperative day (POD) 2, the patient had localized abdominal pain. Follow-up computed tomography suggested a smaller superior mesenteric vein sign and segmental lack of enhancement in the intestinal wall and ascites without SMA occlusion. Thus, the patient was diagnosed with NOMI. Although the patient had type B AD including the SMA, we performed selective mesenteric arteriography and transcatheter papaverine infusion via the SMA and prostaglandin via the peripheral vein. Seven days post treatment, mesenteric blood flow improved and intestinal wall enhancement was restored.

Conclusion

The intra-arterial infusion of a vasodilator is highly efficient and safety treatment option for NOMI with type B AD. Prompt and accurate management can prevent massive small bowel resection, and this procedure is essential in resolving a spasm independent of whether a necrotic bowel has been resected.

Approach to thrombosis at unusual sites: Splanchnic and cerebral vein thrombosis

Splanchnic vein thrombosis (SVT) and cerebral vein thrombosis (CVT) are two manifestations of unusual site venous thromboembolism (VTE). SVT includes thrombosis in the portal, mesenteric or splenic veins, and the Budd-Chiari syndrome. CVT encompasses thrombosis of the dural venous sinuses and thrombosis of the cerebral veins. Unusual site VTE often represents a diagnostic and therapeutic challenge because of the heterogeneity in clinical presentation, the limited evidence available in the literature on the acute and long-term prognosis of these diseases, and the lack of large randomized controlled trials evaluating different treatment options. This narrative review describes the approach to patients with SVT or CVT by examining the diagnostic process, the assessment of potential risk factors and the appropriate anticoagulant treatment.

Accuracy of the smaller superior mesenteric vein sign for the detection of acute superior mesenteric artery occlusion

Aims

The smaller superior mesenteric vein (SMV) sign is a well‐known computed tomography (CT) parameter for acute superior mesenteric artery (SMA) occlusion. This CT sign is potentially beneficial for the early diagnosis of acute SMA occlusion; however, few reports have documented this sign. The present study aimed to determine the accuracy of the smaller SMV sign for the detection of acute SMA occlusion.

Methods

We retrospectively reviewed CT images from 20 patients with acute SMA occlusion and 1,216 controls. We measured the external diameters of the SMV and SMA, and calculated the SMV/SMA diameter ratio. A ratio ≤1 indicated a positive smaller SMV sign.

Results

Of the 20 patients, 14 had the smaller SMV sign, whereas of the 1,216 controls, 88 had the smaller SMV sign. Of the 88 controls with a positive sign, 79 had apparent reasons for the decreased flow in the SMA and nine patients had no reason for the decreased flow. The sensitivity and specificity of the smaller SMV sign for acute SMA occlusion were 70% and 99.2%, respectively.

Conclusion

The smaller SMV sign is an accurate and important CT parameter for the detection of acute SMA occlusion.

Acute mesenteric ischemia: guidelines of the World Society of Emergency Surgery

Acute mesenteric ischemia (AMI) is typically defined as a group of diseases characterized by an interruption of the blood supply to varying portions of the small intestine, leading to ischemia and secondary inflammatory changes. If untreated, this process will eventuate in life threatening intestinal necrosis. The incidence is low, estimated at 0.09–0.2% of all acute surgical admissions. Therefore, although the entity is an uncommon cause of abdominal pain, diligence is always required because if untreated, mortality has consistently been reported in the range of 50%. Early diagnosis and timely surgical intervention are the cornerstones of modern treatment and are essential to reduce the high mortality associated with this entity. The advent of endovascular approaches in parallel with modern imaging techniques may provide new options. Thus, we believe that a current position paper from World Society of Emergency Surgery (WSES) is warranted, in order to put forth the most recent and practical recommendations for diagnosis and treatment of AMI. This review will address the concepts of AMI with the aim of focusing on specific areas where early diagnosis and management hold the strongest potential for improving outcomes in this disease process.

Some of the key points include the prompt use of CT angiography to establish the diagnosis, evaluation of the potential for revascularization to re-establish blood flow to ischemic bowel, resection of necrotic intestine, and use of damage control techniques when appropriate to allow for re-assessment of bowel viability prior to definitive anastomosis and abdominal closure.

Clinical manifestations and imaging tools in the diagnosis of splanchnic and cerebral vein thromboses

Splanchnic vein thrombosis (SVT) and cerebral vein thrombosis (CVT) are uncommon manifestation of venous thromboembolism (VTE), occurring less frequently than deep vein thrombosis of the lower extremities and pulmonary embolism. SVT encompasses portal vein thrombosis, mesenteric vein thrombosis, splenic vein thrombosis and the Budd-Chiari syndrome. It is therefore a heterogeneous disease, with differences in clinical manifestations according to the site of thrombosis. CVT includes thrombosis of the cortical or deep cerebral veins and thrombosis of the major dural venous sinuses. Clinical presentation is variable, with a wide spectrum of signs and symptoms that can mimic other cerebral diseases. There are no clinical algorithms or specific laboratory tests that can guide in the identification of SVT and CVT; therefore, the diagnosis relies exclusively on imaging tests. Conventional angiography once was the gold standard for the diagnosis of SVT and CVT, but it is rarely used nowadays. Abdominal ultrasound (US), computed tomography (CT) and magnetic resonance (MR) with angiography are currently used for the diagnosis of SVT; while cerebral CT and MR with angiography are currently used for the diagnosis of CVT. These imaging tests have different sensitivities/specificities and different advantages/disadvantages that should be kept into consideration when choosing the appropriate imaging test based on the suspected site of thrombosis. This narrative review summarizes the clinical and diagnostic approach to SVT and CVT.