Acute Mesenteric Ischemia

Activate emergency surgical and vascular/endovascular consultation when severe acute abdominal pain is disproportionate to early examination findings, particularly in an older patient with atrial fibrillation, recent myocardial infarction, heart failure, prior arterial embolism, or antecedent postprandial pain with weight loss. These features raise concern for either embolic SMA occlusion or acute thrombosis superimposed on chronic atherosclerotic mesenteric disease. JAMA+2JAMAAcute Mesenteric Ischemia: A Clinical ReviewfacsDiagnosis and Management of Acute Mesenteric Ischemia Is Reviewed | ACSccjm[PDF] Mesenteric ischemia - Cleveland Clinic Journal of Medicine

Escalate directly to urgent operative assessment rather than pursuing serial examinations when guarding, rigidity, rebound tenderness, septic physiology, or hemodynamic deterioration suggests infarcted or perforated bowel. Intestinal resection is required when bowel necrosis is present; mortality remains approximately 50% to 80%, making diagnostic delay a major modifiable hazard. facsfacsDiagnosis and Management of Acute Mesenteric Ischemia Is Reviewed | ACS

Maintain suspicion in ICU and perioperative patients with otherwise unexplained abdominal distension, pain, worsening shock, or rising metabolic derangement during vasopressor-dependent low-flow states. Nonocclusive mesenteric ischemia (NOMI) results from splanchnic hypoperfusion and vasoconstriction and may coexist with sepsis or other critical illness, which can obscure the diagnosis. PubMed+1PubMedBowel Ischemia - StatPearls - NCBI Bookshelfccjm[PDF] Mesenteric ischemia - Cleveland Clinic Journal of Medicine

Order CTA of the abdomen and pelvis with IV contrast as the initial test for suspected AMI. For an AMI protocol, obtain arterial-phase imaging to identify arterial occlusion and enable vascular reconstruction, plus venous-phase imaging to assess intestinal perfusion and venous pathology; multiplanar reconstructions improve evaluation of mesenteric artery origins. CTA is the ACR-recommended initial study and has reported sensitivity and specificity of approximately 96% and 94%, respectively. ScienceDirect+1ScienceDirectACR Appropriateness Criteria® Imaging of Mesenteric Ischemia - ScienceDirectPubMedAcute Mesenteric Ischemia - PMC

Do not substitute plain abdominal radiography or ultrasound for CTA in a patient with meaningful clinical suspicion. Plain films have limited diagnostic value, and ultrasound is not recommended for AMI because it is time-consuming and has limited diagnostic value; CTA is preferred over MRA for speed, availability, and cost in the acute setting. PubMed+1PubMedAcute Mesenteric Ischemia - PMCPubMedBowel Ischemia - StatPearls - NCBI Bookshelf

Interpret CTA in two parallel tracks: identify the cause of vascular compromise and identify signs of established bowel injury. Reduced or absent bowel-wall enhancement is the most specific CT feature of ischemia, with reported specificity near 96%; decreased enhancement is particularly specific for arterial-occlusive ischemia. Bowel-wall thickening, pneumatosis intestinalis, portomesenteric venous gas, mesenteric edema, and mesenteric arterial or venous thromboembolism further support the diagnosis and help define severity. pubs rsna+2pubs rsnaCT and MR Imaging Findings of Bowel Ischemia from Various Primary CausesRadioGraphicspubs rsnaAcute Mesenteric Ischemia: Pathophysiology-based Approach to Imaging Findings and Diagnosis | RadioGraphicsPubMedAcute Mesenteric Ischemia - PMC

Request immediate surgical review of CTA showing reduced enhancement, pneumatosis, portal or mesenteric venous gas, or a vascular occlusion with dilated small bowel. In an elderly AMI cohort, organ failure, elevated serum lactate, and small-bowel dilation on CT were identified as predictors of irreversible bowel-wall necrosis. Nature+2NatureAcute mesenteric ischaemia in the elderly - results of combined endovascular and surgical treatment. Primary study | Scientific ReportsScienceDirectTechniques for intraoperative evaluation of bowel viability in mesenteric ischemia: A review - ScienceDirectpubs rsnaCT and MR Imaging Findings of Bowel Ischemia from Various Primary CausesRadioGraphics

Begin intravenous fluid resuscitation, administer broad-spectrum antibiotics, and initiate anticoagulation as part of initial AMI management while defining the mechanism and procedural plan. These measures do not substitute for revascularization in arterial occlusion or resection when bowel is nonviable. PubMedPubMedBowel Ischemia - StatPearls - NCBI Bookshelf

Use serial abdominal examinations and reassessment of hemodynamics, acid-base status, and lactate trend to identify progression toward transmural injury, but do not delay intervention for laboratory normalization. A soft abdomen may coexist with severe early ischemia; peritoneal signs mark a late and dangerous transition toward infarction or perforation. JAMA+2JAMAAcute Mesenteric Ischemia: A Clinical ReviewfacsDiagnosis and Management of Acute Mesenteric Ischemia Is Reviewed | ACSPubMedAcute Mesenteric Ischemia - PMC

When arterial occlusion is confirmed without clear peritonitis, mobilize endovascular and open vascular capability immediately. Endovascular strategies described for arterial AMI include catheter-directed thrombolysis, aspiration thrombectomy, angioplasty, and stenting; the choice depends on lesion anatomy and local expertise. In one retrospective series, endovascular treatment was technically successful in 87% of treated patients, but this observational result should not defer surgery when bowel viability is uncertain. PubMedPubMedThe role of endovascular therapy in acute mesenteric ischemia - PMC

For arterial embolism, pursue urgent restoration of SMA flow because abrupt occlusion can produce profound ischemia despite intact collateral pathways. Cardiac arrhythmia is a major clinical clue; CTA confirms the occlusion and provides the anatomic basis for endovascular or open revascularization planning. facs+2facsDiagnosis and Management of Acute Mesenteric Ischemia Is Reviewed | ACSPubMedThe role of endovascular therapy in acute mesenteric ischemia - PMCfacsAcute Mesenteric Ischemia: A Rare Complication Following Minimally Invasive Modified McKeown Laparoscopic Esophagectomy | ACS

For acute arterial thrombosis, anticipate underlying ostial or proximal atherosclerotic disease and a history of chronic intestinal angina, nausea, food avoidance, or weight loss. The slow progression of atherosclerosis can permit collateral development, but acute thrombosis converts compensated chronic mesenteric insufficiency into an emergency that requires arterial revascularization and bowel assessment. JAMA+1JAMAAcute Mesenteric Ischemia: A Clinical Reviewccjm[PDF] Mesenteric ischemia - Cleveland Clinic Journal of Medicine

For NOMI, the decisive intervention is correction of the low-flow or vasoconstrictive state while urgently evaluating for bowel necrosis. NOMI should be considered in critically ill patients with abdominal pain requiring vasopressor support; CTA may show ischemic bowel injury without a primary arterial occlusion. Deterioration, peritoneal signs, or CT features of transmural injury should trigger operative exploration rather than continued medical observation. pubs rsna+1pubs rsnaAcute Mesenteric Ischemia: Pathophysiology-based Approach to Imaging Findings and Diagnosis | RadioGraphicsPubMedBowel Ischemia - StatPearls - NCBI Bookshelf

For mesenteric venous thrombosis, identify venous occlusion on CTA and treat with anticoagulation as part of initial management. Proceed to laparotomy when peritonitis, perforation, or necrotic bowel is present; venous thrombosis does not protect against transmural infarction. pubs rsna+1pubs rsnaCT and MR Imaging Findings of Bowel Ischemia from Various Primary CausesRadioGraphicsPubMedBowel Ischemia - StatPearls - NCBI Bookshelf

For strangulating obstruction, source control is mechanical: urgently reduce the hernia, volvulus, or other strangulating lesion and resect gangrenous bowel. Adhesive obstruction may be managed conservatively when feasible, but gangrene mandates resection; complicated hernia and volvulus similarly require reduction or resection with repair directed at the underlying pathology. NatureNatureEtiology, clinical profile, management, and outcomes of intestinal obstruction in a resource-limited setting: a prospective study | Scientific Reports

After revascularization or initial laparotomy, monitor hemodynamics, abdominal findings, lactate and acid-base trend, and evidence of recurrent sepsis or intestinal dysfunction. Persistent shock, worsening examination, or ongoing metabolic deterioration should prompt urgent reassessment for residual ischemia, failed reperfusion, or additional nonviable bowel; serum lactate alone is insufficient to establish bowel viability. Nature+1NatureAcute mesenteric ischaemia in the elderly - results of combined endovascular and surgical treatment. Primary study | Scientific ReportsPubMedAcute Mesenteric Ischemia - PMC

Review the CTA mechanism after stabilization to identify the source of the acute event. Atrial fibrillation, ventricular dysfunction, endocarditis, and arterial atherosclerosis favor arterial embolic or thrombotic mechanisms, whereas critical illness with vasopressor dependence favors NOMI and venous thrombosis may signal hypercoagulable disease, infection, or malignancy. PubMed+1PubMedBowel Ischemia - StatPearls - NCBI Bookshelfccjm[PDF] Mesenteric ischemia - Cleveland Clinic Journal of Medicine

Patients with an acute-on-chronic arterial presentation require longitudinal attention to symptomatic chronic mesenteric insufficiency—postprandial pain, nausea, food aversion, and weight loss—because these features identify the atherosclerotic substrate that preceded the acute event. CTA or contrast-enhanced MRA is appropriate for chronic mesenteric ischemia evaluation when the patient is clinically stable. JAMA+2JAMAAcute Mesenteric Ischemia: A Clinical ReviewScienceDirectACR Appropriateness Criteria® Imaging of Mesenteric Ischemia - ScienceDirectccjm[PDF] Mesenteric ischemia - Cleveland Clinic Journal of Medicine