Diagnostic Role of Multi-Detector Computed Tomography in Acute Mesenteric Ischemia.

Mesenteric ischemia diagnosis is challenging, with an overall mortality of up to 50% of cases despite advances in treatment. The main problem that affects the outcome is delayed diagnosis because of non-specific clinical presentation. Multi-Detector CT Angiography (MDCTA) is the first-line investigation for the suspected diagnosis of vascular abdominal pathologies and the diagnostic test of choice in suspected mesenteric bowel ischemia. MDCTA can accurately detect the presence of arterial and venous thrombosis, determine the extent and the gastrointestinal tract involved, and provide detailed information determining the subtype and the stage progression of the diseases, helping clinicians and surgeons with appropriate management. CT (Computed Tomography) can differentiate forms that are still susceptible to pharmacological or interventional treatment (NOM = non-operative management) from advanced disease with transmural necrosis in which a surgical approach is required. Knowledge of CT imaging patterns and corresponding vascular pathways is mandatory in emergency settings to reach a prompt and accurate diagnosis. The aims of this paper are 1. to provide technical information about the optimal CTA (CT Angiography) protocol; 2. to explain the CTA arterial and venous supply to the gastrointestinal tract and the relevant ischemic pattern; and 3. to describe vascular, bowel, and extraintestinal CT findings for the diagnosis of acute mesenteric ischemia.

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.

Basic demographic characteristics and prevalence of comorbidities in acute mesenteric ischemia: a systematic review and proportional meta-analysis.

PURPOSE: The aim of this systematic review and meta-analysis was to examine and assess the basic demographic characteristics and prevalence of comorbidities in acute mesenteric ischemia (AMI) and its various subtypes. PATIENTS AND METHODS: A literature search was conducted by using the databases PubMed, EMBASE, and Google Scholar (to June 1, 2022). Random-effects or fixed-effects models were selected to pool means and proportions and their corresponding 95% confidence intervals (CI), based on heterogeneity between studies. The results of meta-analyses for basic demographic characteristics and prevalence (proportions) of each specific comorbidities of acute mesenteric ischemia (AMI) and its various subtypes were described. RESULTS: Ninety-nine studies were included in the meta-analysis, including 17,103 patients with AMI. Furthermore, 7941 patients with subclass diagnoses of AMI were identified, including 3,239 patients with arterial occlusive mesenteric ischemia (AOMI), 2,977 patients with nonocclusive mesenteric ischemia (NOMI), and 1,725 patients with mesenteric venous thrombosis (MVT). As a surgical emergency, AMI is associated with older patients and a high likelihood of multisystem comorbidities. Comorbidities of AMI involved multiple systemic diseases, including cardiovascular disease, endocrine and metabolic diseases, kidney diseases, digestive diseases, respiratory diseases, cerebrovascular diseases, vascular diseases, and cancer. CONCLUSION: The basic demographic characteristics and the prevalence of comorbidities of different subtypes of AMI are different. The management of comorbidities should be an essential part of improving the prognosis of AMI patients and may contribute to precise prevention of AMI.

ACR Appropriateness Criteria® Radiologic Management of Mesenteric Ischemia: 2022 Update.

Mesenteric ischemia is a serious medical condition characterized by insufficient vascular supply to the small bowel. In the acute setting, endovascular interventions, including embolectomy, transcatheter thrombolysis, and angioplasty with or without stent placement, are recommended as initial therapeutic options. For nonocclusive mesenteric ischemia, transarterial infusion of vasodilators, such as papaverine or prostaglandin E1, is the recommended initial treatment. In the chronic setting, endovascular means of revascularization, including angioplasty and stent placement, are generally recommend, with surgical options, such as bypass or endarterectomy, considered alternative options. Although the diagnosis of median arcuate ligament syndrome remains controversial, diagnostic angiography can be helpful in rendering a diagnosis, with the preferred treatment option being a surgical release. Systemic anticoagulation is recommended as initial therapy for venous mesenteric ischemia with acceptable rates of recanalization. If anticoagulation fails, transcatheter thrombolytic infusion can be considered with possible adjunctive placement of a transjugular intrahepatic portosystemic shunt to augment antegrade flow. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Acute mesenteric ischemia: The diagnostic value of QT parameters and their relationship with CT findings.

Background One of the greatest challenges in the diagnosis of acute mesenteric ischemia (AMI) is the lack of specific laboratory tests that support multidetector computed tomography (CT). Our aim is to investigate the diagnostic value of electrocardiographic QT parameters in AMI and their relationship with CT findings. Materials and methods Patients who were admitted to the emergency department with abdominal pain were recruited retrospectively from the hospital information system . Grouping was carried out on the basis of AMI(n=78) and non-AMI (n=78). In both groups, the corrected QT (QTc) and QT dispersion (QTD) were measured on electrocardiographs, and the qualitative and quantitative CT findings were evaluated on CT examinations. Results The QTc and QTD values were higher in the AMI group. The median QTc values were 456.16 (IQR: 422.88-483.16) for the AMI group and 388.83 (IQR: 359.74-415.83) for the control group (p<0.001), and the median QTD values were 58 (IQR: 50.3-68.25) for the AMI group and 46 (IQR: 42-50) for the control group (p<0.001). In the CT analysis, the QTc values were significantly higher among AMI patients, with images of paper thin bowel walls and the absence of bowel wall enhancement (p=0.042 and p=0.042, respectively). Meanwhile, the QTD values were significantly higher among patients with venous pneumatosis findings on CT (p=0.005). In the regression analysis, a significant relationship was found between the QT parameters and AMI (p<0.001). For QTc, an AUC of 0.903 (95% CI: 0.857-0.950, p<0.001), a sensitivity of 80.8%, and a specificity of 82.3% were found. For QTD, an AUC of 0.821 (95% CI: 0.753-0.889, p<0.001), a sensitivity of 73.1%, and a specificity of 82.3% were found. Conclusion We found the QTc and QTD values to be significantly higher among AMI patients. Furthermore, we found a significant relationship between the CT findings and QTc and QTD as well as a significant relationship between survival and QTc in the AMI group.

Relationship between subarachnoid hemorrhage and nonocclusive mesenteric ischemia as a fatal complication: patient series.

BACKGROUND: Nonocclusive mesenteric ischemia (NOMI) causes intestinal necrosis due to irreversible ischemia of the intestinal tract. The authors evaluated the incidence of NOMI in patients with subarachnoid hemorrhage (SAH) due to ruptured aneurysms, and they present the clinical characteristics and describe the outcomes to emphasize the importance of recognizing NOMI. OBSERVATIONS: Overall, 7 of 276 consecutive patients with SAH developed NOMI. Their average age was 71 years, and 5 patients were men. Hunt and Kosnik grades were as follows: grade II, 2 patients; grade III, 3 patients; grade IV, 1 patient; and grade V, 1 patient. Fisher grades were as follows: grade 1, 1 patient; grade 2, 1 patient; and grade 3, 5 patients. Three patients were treated with endovascular coiling, 3 with microsurgical clipping, and 1 with conservative management. Five patients had abdominal symptoms prior to the confirmed diagnosis of NOMI. Four patients fell into shock. Two patients required emergent laparotomy followed by second-look surgery. Four patients could be managed conservatively. The overall mortality of patients with NOMI complication was 29% (2 of 7 cases). LESSONS: NOMI had a high mortality rate. Neurosurgeons should recognize that NOMI can occur as a fatal complication after SAH.

Non-Occlusive Mesenteric Ischemia in Children With Diabetic Ketoacidosis: Case Report and Review of Literature.

Introduction: Despite the use of technology, recurrent diabetic ketoacidosis (DKA) prevention remains an unmet need in children and adolescents with T1D and may be accompanied by life-threatening acute complications. We present a rare case of non-occlusive mesenteric ischemia (NOMI) with overt manifestation after DKA resolution and a discussion of recent literature addressing DKA-associated NOMI epidemiology and pathogenesis in children and adolescents. Case Presentation: A 13-year-old female with previously diagnosed T1D, was admitted at our emergency department with hypovolemic shock, DKA, hyperosmolar state and acute kidney injury (AKI). Mildly progressive abdominal pain persisted after DKA correction and after repeated ultrasound evaluations ultimately suspect for intestinal perforation, an intraoperative diagnosis of NOMI was made. Conclusion: The diagnosis of DKA-associated NOMI must be suspected in pediatric patients with DKA, persistent abdominal pain, and severe dehydration even after DKA resolution.

Nonocclusive mesenteric ischemia caused by type B aortic dissection: a case report.

BACKGROUND: Nonocclusive mesenteric ischemia (NOMI) is defined as acute intestinal ischemia because of decreased blood flow in mesenteric vessels. Only a few cases of NOMI that occur secondary to aortic dissection (AD) have been reported, resulting in the lack of sufficient knowledge of diagnosis and treatment. CASE PRESENTATION: We aimed to report a case of NOMI caused by type B Aortic Dissection. A 26-year-old male patient was transferred to our hospital with the diagnose of NOMI and aortic dissection in April 2018. The abdominal computed tomography (CT) assists the diagnosis of paralytic intestinal obstruction, intestinal wall pneumatosis, and perforation. Emergency laparotomy revealed that the bowel wall supplied by the superior mesenteric artery (SMA) was pale with the palpable but weak pulsation of the parietal artery. The small intestine was extremely dilated with a paper-thin, fragile wall that was ruptured easily and could not be sutured. In this case, extensive resection and segmental drainage were done. Postoperatively, the digestive tract was reconstructed. However, the patient suffered from iron deficiency anemia and short bowel syndrome eight months later, and unfortunately died from long-term complications. CONCLUSION: Aortic dissection leads to continuous decrease in blood pressure and blood flow to the SMA, considering as a predisposing factor for NOMI. During the treatment, extensive resection and segmental drainage are the optimal surgical strategy, which can make benefit in emergencies especially.

Unusual computed tomography findings of gas in the superior mesenteric artery system with no signs of porto-mesenteric venous gas in a case of acute mesenteric ischemia.

Acute Mesenteric Ischemia (AMI) is a rare life-threatening entity caused by sudden interruption of the blood supply to a segment of the bowel due to impairment of mesenteric arterial blood flow or venous drainage. Clinical presentation varies according to the time course of vascular occlusion. Contrast-enhanced Computed Tomography (CT) of the abdomen represents the main diagnostic test for AMI diagnosis, enabling fast and excellent evaluation of the intestine, mesenteric vasculature, and other ancillary characteristics of AMI. Typical CT findings of AMI include paralytic ileus, decreased or absent bowel wall contrast-enhancement, pneumatosis intestinalis, and porto-mesenteric venous gas. We hereby report a case of an 89-year-old man presenting with AMI due to Superior Mesenteric Artery (SMA) thrombotic occlusion following endovascular stenting superficial femoral arteries. Typical findings were observed on abdominal CT imaging, yet associated with the presence of gas exclusively in the SMA district, without any involvement of the porto-mesenteric venous system. Different imaging features and pitfalls can help radiologists to accurately diagnose AMI, especially when irreversible bowel damage is about to occur. Therefore, radiologists and emergency physicians should be aware of the unusual association between gas in the SMA arterial district and AMI, even in the absence of porto-mesenteric venous system involvement, in order to urge prompt surgical consultation when observed.

Predictors and severity of intestinal ischaemia following on-pump cardiac surgery: a retrospective, propensity-matched analysis.

OBJECTIVES: Risk factors associated with intestinal ischaemia after heart surgery have been previously explored; however, a paucity of data exists with regard to extent of intestinal ischaemia in patients requiring surgical intervention. The purpose of this study is to assess predictors of abdominal exploration and extent of ischaemia following cardiac surgery. METHODS: A retrospective single-centre study was performed at a university hospital. The patient sample included consecutive patients between 2009 and 2020 who first received cardiac and then abdominal exploration during the same hospital stay. Control group patients were identified by 1:1 propensity matching. Logistic regression was performed to identify risk factors for laparotomy. Patients of the laparotomy group were further analysed for intraoperative findings from required abdominal operations. RESULTS: A total of 6832 patients were identified, of whom 70 (1%) underwent abdominal exploration. The median time to exploratory laparotomy was 6 days with no difference between intraoperatively confirmed ischaemia versus those who underwent negative exploration. Thirty-day mortality was 51%. Prior diagnosis of COPD or administration of 2 or more vaso-inotropes during the postoperative phase was independent risk factors for exploratory laparotomy. Vaso-inotrope use was a strong independent predictor of extent of intestinal ischaemia as well as for 30-day mortality. Degree of intestinal ischaemia was also an independent predictor of 30-day mortality. CONCLUSIONS: Intestinal ischaemia is a feared complication after cardiac surgery with high mortality, often necessitating multiple abdominal procedures. Administration of 2 or more vaso-inotropes in the postoperative phase of cardiac procedure is a strong predictor for the degree of ischaemia and 30-day mortality.

The role of bed-side laparoscopy in the management of acute mesenteric ischemia of recent onset in post-cardiac surgery patients admitted to ICU.

PURPOSE: Acute mesenteric ischemia with non-occlusive mechanism (NOMI) is a possible complication after cardiac surgery in patients admitted to Intensive Care Unit (ICU). Since the diagnosis is often difficult with CT-scan, some authors have evaluated the role of bed-side diagnostic laparoscopy (DL). We aimed to contribute to this topic with a personal series. METHODS: We retrospectively evaluated patients admitted to ICU after cardiac surgery since 2009 up to 2019, successively operated on for a suspected NOMI of recent onset with non-conclusive CT. They were divided into laparoscopic (Ls) and laparotomic (Lt) group, depending on whether or not they had a DL. They were compared for the CT false-positive (FP) and true-positive (TP) rate and the surgical outcome. RESULTS: Seventy-three patients were enrolled. Lt included 30 patients (41%), Ls 43 (59%). The overall FP were 38 (52%), with a higher incidence in Ls. There was no difference in the mortality rate. The morbidity rate was higher in Lt, and especially in Lt-FP. The TP were 35 (47.9%). The mean operating time (OT) in the Lt-TP group was similar to the sum of the mean OT of the laparotomies plus that of the laparoscopies in the Ls-TP group. Conversely, when considering only laparotomic procedures, the Lt-TP had higher mean OT, such as an increased blood loss CONCLUSIONS: Post-cardiosurgical patients admitted to ICU have a relatively high rate of NOMI, in which CT-scan is often initially non-conclusive. Our data and those from the literature seem to show that in such cases bed-side DL may be an advantageous and safe procedure to avoid needless laparotomy and enables a more tailored open surgery.

Accuracy of OMI ECG findings versus STEMI criteria for diagnosis of acute coronary occlusion myocardial infarction.

OBJECTIVE: In the STEMI paradigm of Acute Myocardial Infarction (AMI), many NSTEMI patients have unrecognized acute coronary occlusion MI (OMI), may not receive emergent reperfusion, and have higher mortality than NSTEMI patients without occlusion. We have proposed a new OMI vs. Non-Occlusion MI (NOMI) paradigm shift. We sought to compare the diagnostic accuracy of OMI ECG findings vs. formal STEMI criteria for the diagnosis of OMI. We hypothesized that blinded interpretation for predefined OMI ECG findings would be more accurate than STEMI criteria for the diagnosis of OMI. METHODS: We performed a retrospective case-control study of patients with suspected acute coronary syndrome. The primary definition of OMI was either 1) acute TIMI 0-2 flow culprit or 2) TIMI 3 flow culprit with peak troponin T ≥ 1.0 ng/mL or I ≥ 10.0 ng/mL. RESULTS: 808 patients were included, of whom 49% had AMI (33% OMI; 16% NOMI). Sensitivity, specificity, and accuracy of STEMI criteria vs Interpreter 1 using OMI ECG findings among 808 patients were 41% vs 86%, 94% vs 91%, and 77% vs 89%, and for Interpreter 2 among 250 patients were 36% vs 80%, 91% vs 92%, and 76% vs 89%. STEMI(-) OMI patients had similar infarct size and mortality as STEMI(+) OMI patients, but greater delays to angiography. CONCLUSIONS: Blinded interpretation using predefined OMI ECG findings was superior to STEMI criteria for the ECG diagnosis of Occlusion MI. These data support further investigation into the OMI vs. NOMI paradigm and suggest that STEMI(-) OMI patients could be identified rapidly and noninvasively for emergent reperfusion using more accurate ECG interpretation.

A case of non-occlusive mesenteric ischaemia caused by pelvic fracture due to fall trauma.

BACKGROUND: Non-occlusive mesenteric ischaemia (NOMI) is a condition in which intestinal ischaemia arises due to spasms of peripheral blood vessels; however, there is no obstruction of the main arteries. Risk factors include hypertension, diabetes, and increasing age, but the traumatic injury triggering NOMI onset is rarely reported. We report a case of NOMI caused by a pelvic fracture due to a fall injury. CASE PRESENTATION: A 77-year-old man was transported to the hospital due to a fall injury. CT revealed a pelvic fracture and a haematoma in the pelvic extraperitoneal space. The next day, the patient developed shock, and CT revealed an increase in haematoma size. Both internal iliac arteries were embolized by transcatheter arterial embolization (TAE). The next day's CT revealed intestinal necrosis of the ascending colon, and emergency surgery was planned. During surgery, necrosis was identified in the serosa of the ascending, transverse, and sigmoid colon. We performed subtotal excision from the ascending colon to the sigmoid colon. On postoperative day 10, melena was observed, and CT revealed partial thickening of the small intestine and a decrease in the contrast effect. Considering the post-total colectomy and general condition, we proceeded with conservative treatment. Over time, the patient developed liver and renal dysfunction and died 16 days after surgery. CONCLUSIONS: We experienced a case of NOMI caused by bleeding from a pelvic fracture. It is important to keep in mind the risk of developing NOMI in traumatic bleeding to avoid missing this diagnosis.

Don't Trust the Imaging: Necrotic Bowel Following Transcatheter Aortic Valve Replacement Through Aortic Stent Graft.

Mesenteric ischemia is a rare but lethal complication of transcatheter aortic valve replacement (TAVR). We present a challenging case of an 80-year-old man who had abdominal pain few hours following TAVR. Repeated abdominal and pelvic imaging showed no vascular obstruction, but exploratory laparoscopy revealed a necrotic bowel. (Level of Difficulty: Intermediate.).

Small-intestinal necrosis due to non-occlusive mesenteric ischemia with diabetic ketoacidosis after quetiapine treatment.

We report a 66-year-old male who developed diabetic ketoacidosis (DKA) and necrosis of the small intestine due to non-occlusive mesenteric ischemia (NOMI), 3 months after starting quetiapine treatment. He was transferred to our hospital and diagnosed as diabetic for the first time, associated with DKA. Despite improvement in DKA, abdominal pain worsened gradually 10 h after hospitalization. Computed tomography (CT) revealed bowel emphysema, and gas out of the gut wall, in the mesenteric veins and the intrahepatic portal vein, suggesting intestinal necrosis. He survived because of resection of necrotic small-intestinal tissue and he finally required no diabetes treatment. Mesenteric arteries were patent with good palpitation without occlusion or thrombosis, and pathological findings showed ischemic enteritis, which is consistent with NOMI. DKA is a rare but serious side effect of second-generation antipsychotic medications (SGAMs) such as quetiapine, which can result in NOMI: a life-threatening complication. We must keep in mind that the plasma glucose concentration may increase in patients taking SGAMs, or that NOMI may occur concurrently if DKA develops.

Non-occlusive mesenteric ischemia induced by a polyethylene glycol with ascorbate-based colonic bowel preparation.

Although conventional bowel preparation for colonoscopy rarely causes serious complications, such complications can be fatal and, therefore, require early recognition and prompt treatment. Herein, we report a case of non-occlusive mesenteric ischemia (NOMI) induced by polyethylene glycol with an ascorbate component (PEG + Asc) that was used as a colonic bowel preparation. An- 82-year-old woman with a medical history of hypertension, atrial fibrillation and mild chronic renal failure received a cancer screening colonoscopy. Four hours after the administration of PEG + Asc, she vomited and gradually developed abdominal distention. She went into hypovolemic shock, and a CT scan revealed a distal colon obstruction caused by fecal material. A colonoscopy identified focal necrotic mucosa between the rectum and descending colon, suggesting the occurrence of irreversible intestinal necrosis; consequently, she underwent emergency surgery. The operative and pathological findings showed a discontinuous area of necrosis from the anal margin to the ileum without thrombotic change in the main mesenteric arteries, consistent with a diagnosis of NOMI. NOMI is a rare but fatal disease that can advance to an irreversible stage before a definite diagnosis can be made. Since PEG + Asc is a hypertonic laxative solution, the possibility that dehydration might cause severe secondary complications must be considered.

Non-occlusive intestinal ischemia in the ascending colon and rectum: a pediatric case occurring during encephalitis treatment.

BACKGROUND: Non-occlusive mesenteric ischemia (NOMI) is a rare and severe pathological condition that can cause intestinal necrosis without mechanical obstruction of the mesenteric artery. NOMI often develops during the treatment of severe disease in elderly patients and mostly occurs in the intestine supplied by the superior mesenteric artery (SMA). We experienced a 12-year-old patient with NOMI that was segmentally localized in the ascending colon and rectum during encephalitis treatment. CASE PRESENTATION: A 12-year-old boy was hospitalized with limbic encephalitis. On day 41 after admission, he abruptly developed hypotension following diarrhea and fever, and presented abdominal distension. A computed tomography scan revealed pneumatosis intestinalis localized in the ascending colon and rectum coexisting with portal venous gas. The presence of peritoneal signs required an emergency laparotomy. Intraoperatively, skip ischemic lesions were found in the ascending colon and the rectum without bowel perforation. SMA and superior rectal arterial pulsation were present, and the patient was diagnosed with NOMI. The remaining colon, from the transverse to the sigmoid colon, appeared intact. We performed a distal ileostomy without bowel resection. Postoperative colonoscopies were carried out and revealed rectal and ascending colon stenosis with ulceration but demonstrated the patency of the two lesions. We confirmed the improvement of the transient bowel strictures; therefore, the ileal stoma was closed 14 months after the previous laparotomy. CONCLUSION: NOMI can be present in childhood during encephalitis treatment and can be segmentally localized in the ascending colon and the rectum. Although NOMI is most often seen in elderly patients, we should also consider the possibility of NOMI when pediatric patients with severe illness manifest abdominal symptoms.

The Pathogenesis of Nonocclusive Mesenteric Ischemia: Implications for Research and Clinical Practice.

Nonocclusive mesenteric ischemia (NOMI) is a condition that can encompass ischemia, inflammation, and infarction of the intestinal wall. In contrast to most patients with acute mesenteric ischemia, NOMI is distinguished by patent arteries and veins. The clinical presentation of NOMI is often insidious and nonspecific, resulting in a delayed diagnosis. Patients most at risk are those with severe acute and critical disease, including major surgery and trauma. Nonocclusive mesenteric ischemia is part of a spectrum, from mild, asymptomatic, and an unexpected finding on CT scanning, through to those exhibiting abdominal distension and peritonitis. Severe NOMI is associated with a significant mortality rate. This review of NOMI pathophysiology was conducted to document current concepts and evidence, to examine the implications for diagnosis and treatment, and to identify gaps in knowledge that might direct future research. The key pathologic mechanisms involved in the genesis of NOMI represent an exaggerated normal physiological response to maintain perfusion of vital organs at the expense of mesenteric perfusion. A supply-demand mismatch develops in the intestine due to the development of persistent mesenteric vasoconstriction resulting in reduced blood flow and oxygen delivery to the intestine, particularly to the vulnerable superficial mucosa. This mismatch can be exacerbated by raised intra-abdominal pressure, enteral nutrition, and the use of certain vasoactive drugs, ultimately resulting in the development of intestinal ischemia. Strategies for prevention, early detection, and treatment are urgently needed.

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.