Colonic involvement in acute mesenteric ischemia: prevalence, risk factors, and outcomes

Acute arterial mesenteric ischaemia: comparison of partial and complete occlusion of the superior mesenteric artery

OBJECTIVES

To describe the characteristics and outcomes of patients with an incomplete occlusion of the superior mesenteric artery (SMA) (persistence of contrast-enhanced vessel lumen) and compare them to those with a complete occlusion of the SMA (complete interruption of the contrast-enhanced vessel lumen) in arterial acute mesenteric ischaemia (AMI).

MATERIAL AND METHODS

Retrospective study of arterial AMI patients (2006-2022). Demographics, laboratory tests, clinical characteristics, CT, treatments and outcomes were compared between patients with complete or incomplete SMA obstruction after adjusting for aetiology (embolic or atherosclerotic). The primary outcome was 30-day mortality, and the secondary outcome was 6-month gastrointestinal disability-free survival (no short bowel syndrome or parenteral nutritional support or permanent stoma).

RESULTS

151 patients (65 women, mean age 69) were included, 62 (41%) with incomplete and 89 (59%) with occlusive SMA occlusion. After adjusting for aetiology, chronic kidney failure (p = 0.03) and normal bowel enhancement on CT (p < 0.01) were associated with incomplete SMA occlusion. Patients with incomplete SMA occlusion were more frequently treated by endovascular revascularisation (p < 0.01) and stenting (p < 0.01), while patients with complete SMA occlusion were treated by open revascularisation. The 30-day mortality rate was 13% with no difference between incomplete (11%) and complete SMA occlusion (15%; p = 0.89). Nevertheless, complete SMA occlusion patients had a lower 6-month gastrointestinal disability-free survival rate (p = 0.01), more transmural necrosis (p < 0.01) and a higher risk of gastrointestinal disability (p = 0.02).

CONCLUSION

Incomplete SMA occlusion can cause AMI with a similar 30-day mortality rate to completely occlusive forms. However, it is associated with poorer gastrointestinal outcomes, regardless of aetiology.

CRITICAL RELEVANCE STATEMENT

Acute arterial mesenteric ischaemia caused by incomplete occlusion of the superior mesenteric artery demonstrates similar 30-day mortality to complete occlusion but distinctively better gastrointestinal outcomes, emphasising nuanced imaging evaluation for targeted management strategies in these patients.

KEY POINTS

Occlusive acute mesenteric ischaemia can be caused by incomplete superior mesenteric artery (SMA) occlusion. Acute mesenteric ischaemia caused by incomplete SMA occlusion has a similar 30-day mortality rate to complete SMA occlusion. A complete occlusion of the SMA is associated with poorer gastrointestinal outcomes.

Acute Abdominal Pain With Gastrointestinal Wall Thickening and Edema: Insights From Two Case Reports

Gastrointestinal diseases encompass a wide range of etiologies, including tumor-related, infectious, ischemic, immune-mediated, and vascular conditions, all of which can present with similar imaging features. Among these, phlegmonous gastroenteritis is a rare, acute gastrointestinal infection characterized by purulent inflammation in the submucosal and muscular layers of the gastrointestinal wall. Clinical manifestations typically include sudden abdominal pain, nausea, vomiting, fever, and abdominal distension, with imaging showing gastrointestinal wall thickening and stromal edema. The disease's nonspecific clinical and imaging features often lead to misdiagnosis. This report describes two cases of acute abdominal pain with gastrointestinal wall thickening and edema, providing insights into the early identification of phlegmonous gastroenteritis. Both patients recovered completely after empirical antibiotic therapy, highlighting the importance of early imaging diagnosis, endoscopy, and histopathological analysis in managing this rare condition. Early recognition and intervention are essential to prevent severe complications and improve patient outcomes.

Irreversible Transmural Intestinal Necrosis in Acute Mesenteric Ischemia: Retrospective Cohort Study from a High-Volume Hospital

Background: Owing to the low incidence rate and nonspecific symptoms of acute mesenteric ischemia (AMI), the identification and prediction of irreversible transmural intestinal necrosis (ITIN) and extensive bowel resection (≥100 cm) (EBR) are difficult and critical. This study aimed to investigate the risk factors for ITIN and EBR in patients with AMI. Methods: The clinical data of 254 AMI patients were retrospectively analyzed. Furthermore, the incidence of ITIN and EBR were set as dependent variables, and relevant risk factors were screened using univariate and multivariate logistic regression analyses. The comparisons of surgical characteristics and postoperative recovery outcomes between the EBR and control group were also conducted. Results: The presence of hemorrhagic (odds ratio [OR] = 28.356, P < .001) or other types ascites (OR = 13.051, P = .003), peritonitis (OR = 8.463, P = .005), intestinal diameter >2.35 cm (OR = 5.493, P = .020), and serum creatinine (CREA) >95 μmol/L (OR = 4.866, P = .048) were identified as independent risk factors for ITIN in patients with AMI. In addition, serum C-reactive protein (CRP) >15 mg/L (OR = 38.023, P = .006), and CREA >100 μmol/L (OR = 6.248, P = .035) were proved to be independently associated with EBR for ITIN cases. Compared to the control group, EBR significantly increased the likelihood of requiring enterostomy (P = .001), blood transfusion (P = .002), and transfer to intensive care unit (P = .016), while also prolonging the recovery time for intestinal function (P = .014). Conclusions: The presence of ascites, peritonitis, intestinal diameter >2.35 cm, and serum CREA >95 μmol/L were independently correlated with ITIN for AMI cases, while serum CRP >15 mg/L and CREA >100 μmol/L independently increased the risk of EBR.

Predictors of Survival Without Intestinal Resection after First-Line Endovascular Revascularization in Patients with Acute Arterial Mesenteric Ischemia

Background Acute arterial mesenteric ischemia requires emergency treatment and is associated with high mortality rate and poor quality of life. Identifying factors associated with survival without intestinal resection (hereafter, intestinal resection-free [IRF] survival) could help in treatment decision-making after first-line endovascular revascularization. Purpose To identify factors associated with 30-day IRF survival in patients with acute arterial mesenteric ischemia whose first-line treatment was endovascular revascularization. Materials and Methods Patients with acute arterial mesenteric ischemia whose first-line treatment was endovascular revascularization because of a low probability of bowel necrosis were included in this single-center retrospective cohort (May 2014 to August 2022). Patient demographics, laboratory values, clinical characteristics at admission, CT scans, angiograms, and endovascular revascularization-related variables were included. The primary end point was 30-day IRF survival, and secondary end points were 3-month, 1-year, and 3-year overall survival. Factors independently associated with 30-day IRF survival were identified with binary logistic regression. Results A total of 117 patients (median age, 70 years [IQR, 60-77]; 53 female, 64 male) were included. Within 30 days after revascularization, 73 of 117 patients (62%) survived without resection, 28 of 117 (24%) survived after resection, 14 of 117 (12%) died without resection, and two of 117 (2%) underwent resection but died. The 30-day IRF survival was 63% (74 of 117). The 3-month, 1-year, and 3-year mortality rate was 18% (21 of 117), 21% (25 of 117), and 27% (32 of 117), respectively. Independent predictors of 30-day IRF survival were persistent bowel enhancement at initial CT (odds ratio [OR], 0.3; 95% CI: 0.2, 0.8; P = .013) and C-reactive protein (CRP) level less than 100 mg/L (OR, 0.3; 95% CI: 0.1, 0.8; P = .002). The 30-day IRF survival was 86%, 61%, 47%, and 23% in patients with both favorable features, persistent bowel enhancement but CRP level greater than 100 mg/L, no bowel enhancement but CRP level less than 100 mg/L, and both unfavorable features, respectively. Conclusion Independent predictors associated with 30-day IRF survival in patients with acute arterial mesenteric ischemia whose first-line treatment was endovascular revascularization were persistent bowel wall enhancement at initial CT and CRP level less than 100 mg/L. © RSNA, 2024 Supplemental material is available for this article.

Revascularization Strategies for Acute and Chronic Mesenteric Ischemia: A Narrative Review

Mesenteric ischemia is a challenging condition characterized by insufficient blood perfusion to the mesentery and, consequently, intestinal tissues that continues to perplex clinicians. Despite its low prevalence, the condition's variable clinical presentation and elusive radiographic diagnosis can delay life-saving interventions in the acute setting and deteriorate the quality of life of patients when left undiagnosed or misdiagnosed.

PURPOSE

Review and summarize recent diagnostic updates and emergent intervention strategies for acute and chronic mesenteric ischemia.

METHODS

A narrative review of all relevant studies from January 2022 through September 2023.

RESULTS

A total of 11 studies from MEDLINE, supplemented with 44 studies from Google Scholar, were included in the review.

CONCLUSIONS

Both acute and chronic mesenteric ischemia propose diagnostic and therapeutic challenges for interventionalists. Computed tomographic angiography remains the diagnostic modality of choice for both. Open surgical intervention remains the gold standard for acute mesenteric ischemia, while endovascular techniques are preferred for chronic mesenteric ischemia.

Insights into acute mesenteric ischaemia: an up-to-date, evidence-based review from a mesenteric stroke centre unit

Radiologists play a central role in the diagnostic and prognostic evaluation of patients with acute mesenteric ischaemia (AMI). Unfortunately, more than half of AMI patients undergo imaging with no prior suspicion of AMI, making identifying this disease even more difficult. A confirmed diagnosis of AMI is ideally made with dynamic contrast-enhanced CT but the diagnosis may be made on portal-venous phase images in appropriate clinical settings. AMI is diagnosed on CT based on the identification of vascular impairment and bowel ischaemic injury with no other cause. Moreover, radiologists must evaluate the probability of bowel necrosis, which will influence the treatment options.AMI is usually separated into different entities: arterial, venous, non-occlusive and ischaemic colitis. Arterial AMI can be occlusive or stenotic, the dominant causes being atherothrombosis, embolism and isolated superior mesenteric artery (SMA) dissection. The main finding in the bowel is decreased wall enhancement, and necrosis can be suspected when dilatation >25 mm is identified. Venous AMI is related to superior mesenteric vein (SMV) thrombosis as a result of a thrombophilic state (acquired or inherited), local injury (cancer, inflammation or trauma) or underlying SMV insufficiency. The dominant features in the bowel are hypoattenuating wall thickening with submucosal oedema. Decreased enhancement of the involved bowel suggests necrosis. Non-occlusive mesenteric ischaemia (NOMI) is related to impaired SMA flow following global hypoperfusion associated with low-flow states. There are numerous findings in the bowel characterised by diffuse extension. An absence of bowel enhancement and a thin bowel wall suggest necrosis in NOMI. Finally, ischaemic colitis is a sub-entity of arterial AMI and reflects localised colon ischaemia-reperfusion injury. The main CT finding is a thickened colon wall with fat stranding, which seems to be unrelated to SMA or inferior mesenteric artery lesions. A precise identification and description of vascular lesions, bowel involvement and features associated with transmural necrosis is needed to determine patient treatment and outcome.