Suspected acute mesenteric ischaemia (adult)
Severe abdominal pain out of proportion to examination: treat as AMI until disproven
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GastroenterologyEmergency
Acute Mesenteric Ischemia Management (ESVS)
Acute Mesenteric Ischemia Management (ESVS): Suspected acute mesenteric ischaemia (adult) → Recognise AMI early: high index of suspicion → Start at once...
Pathway Overview
20 steps
Algorithm Steps
20 total
01Start 02Action Recognise AMI early: high index of suspicion
Classic signs are often absent. Peritonitis is a late sign (bowel necrosis).
- Sudden severe abdominal pain, pain out of proportion to examination
- Risk factors: AF, recent MI, heart failure, atherosclerosis, prior embolism, thrombophilia, cirrhosis
- Early gut emptying: vomiting, diarrhoea; later distension, GI bleeding
- NOMI: critically ill patient on vasopressors with new organ failure, distension or GI bleeding; pain may be absent if sedated
- Do not wait for lab results before CT angiography
03Action Start at once, in parallel with imaging: resuscitate
Do not delay CT angiography or surgery for these steps
- Goal-directed IV fluids with haemodynamic monitoring. Heart failure or cardiogenic shock: small boluses and reassess often
- Broad-spectrum IV antibiotics now (choose by local guideline and allergy status)
- Full-dose heparin: start after CTA confirms AMI and excludes aortic dissection or bleeding (see below). Do not delay CTA for heparin
- Correct acidosis and electrolytes; check potassium (risk of hyperkalaemia with infarction and reperfusion)
- Nasogastric decompression; nil by mouth
- Vasopressors, vasopressin and digoxin can worsen gut ischaemia: restore volume and cardiac output first; lowest vasopressor dose that keeps perfusion. Do not stop vasopressors needed for shock
04Action Call senior surgeon, vascular surgeon and interventional radiology now
Time to revascularisation decides bowel survival
- Multidisciplinary team: emergency or general surgeon, vascular surgeon, interventional radiologist, intensivist
- No 24/7 open and endovascular revascularisation on site: arrange urgent transfer to a centre that has it
- Keep resuscitating during transfer
05Action Bloods with IV access (supportive only)
Normal results do NOT rule out AMI
- Lactate, blood gas, FBC (WCC), D-dimer, UEC, amylase, coagulation, group and hold
- Raised lactate, WCC and D-dimer support the diagnosis but are not specific
- Normal lactate does not exclude AMI
- Amylase can be raised in AMI: do not misdiagnose as pancreatitis
06Action CT angiography without delay
Test of choice for any suspected AMI
- Biphasic CTA: arterial and portal venous phases; no oral contrast
- Do CTA even with acute kidney injury: a missed diagnosis is more harmful than the contrast
- Shows: arterial embolus or thrombus, venous thrombus, patent vessels with poor bowel enhancement (NOMI)
- Signs of necrosis: bowel wall non-enhancement, pneumatosis, portal venous gas, free air
07Decision CTA shows acute mesenteric ischaemia?
Arterial or venous occlusion, or signs of NOMI (poor bowel enhancement, pneumatosis, portal venous gas without SMA stenosis)
- If Yes
08Warning Before full-dose heparin: exclude aortic dissection, rupture, bleeding, HIT
Start heparin as soon as these are excluded. Do not delay surgery or revascularisation for it.
- Aortic dissection, ruptured or leaking aneurysm, or active bleeding: no heparin until the vascular surgeon decides
- Recent intracranial haemorrhage or heparin-induced thrombocytopenia: no heparin; HIT: non-heparin anticoagulant with haematology
- Already on warfarin or a DOAC: plan heparin timing and reversal with the surgeon and haematology; do not delay surgery
09Action AMI confirmed, no contraindication: start full-dose IV unfractionated heparin
Arterial AMI and venous thrombosis. NOMI: consider heparin; give it with any intra-arterial vasodilator
- Infusion by local weight-based aPTT or anti-Xa protocol
- Unfractionated heparin is preferred when surgery or intervention is likely: short-acting and reversible
- Venous thrombosis without planned intervention: LMWH is an alternative
- Continue antibiotics and resuscitation
10Decision Peritonitis or CT signs of bowel necrosis?
Peritoneal signs, free air, pneumatosis with portal venous gas, non-enhancing bowel
- If Yes
11Action Peritonitis or necrosis: emergency laparotomy
Operate after initial resuscitation, without further delay
- Arterial occlusion: revascularise first, then resect (embolectomy, bypass or retrograde open stent; temporary SMA shunt if in extremis)
- Laparotomy is preferred: bowel viability is hard to judge at laparoscopy
- Resect only frankly necrotic bowel; leave doubtful bowel for a planned second look
- Damage control with temporary abdominal closure; second look within 24 to 48 h
- No vascular service on site: resect clearly necrotic bowel sparingly, temporary closure, transfer for revascularisation
- MVT or NOMI: usually no vascular repair; continue heparin
- Massive necrosis in a frail patient: discuss goals of care; palliation may be appropriate
12Action After treatment: ICU care and secondary prevention
Treat long-term by cause
- ICU: optimise gut perfusion, prevent organ failure; limit crystalloid (abdominal compartment syndrome)
- Continue heparin after surgery unless bleeding (NOMI: if started); antibiotics for at least 4 days, tailored to cultures
- Embolic cause (for example AF): find the source (ECG monitoring, echocardiography); long-term anticoagulation
- Atherosclerotic thrombosis: antiplatelet and statin. After SMA stent: aspirin plus clopidogrel for at least 1 month (some centres 6 months), then lifelong single antiplatelet. Anticoagulate only for another indication
- MVT: anticoagulation 3 to 6 months, indefinite if unprovoked or a permanent risk factor; no DOAC in pregnancy, antiphospholipid syndrome or Child-Pugh C
- Surveillance imaging (duplex or CTA) of stent or bypass within 6 months
- Extensive resection: early nutrition and intestinal failure team
13Outcome Survival
Early diagnosis and fast revascularisation improve survival
14Outcome Short bowel syndrome
After extensive resection; may need long-term parenteral nutrition and intestinal failure care
If No15Decision No peritonitis: what is the cause on CTA?
Embolus (often AF, abrupt onset), atherosclerotic thrombosis (subacute, prior chronic symptoms), venous thrombosis, or non-occlusive (low-flow state)
- Arterial embolus or thrombosis
16Action Arterial embolus or thrombosis, no peritonitis: urgent revascularisation
Endovascular first where expertise is available; open surgery if not
- Options: aspiration embolectomy, catheter-directed thrombolysis, angioplasty and stent
- No thrombolysis with: recent surgery, trauma or ischaemic stroke; any intracranial haemorrhage or lesion; GI or other active bleeding; bleeding disorder; uncontrolled hypertension; endocarditis
- Open embolectomy or bypass if endovascular treatment fails or is not available
- Low threshold to inspect the bowel (laparotomy) after revascularisation
- Peritonitis, worsening pain or rising lactate: emergency laparotomy
- Path rejoins step 12Shared downstream outcome
- Venous thrombosis
17Action Mesenteric venous thrombosis, no peritonitis: anticoagulation
IV unfractionated heparin or LMWH is first-line treatment
- Continue heparin (LMWH if no intervention is planned); bowel rest, NG suction, fluids
- No DOAC in pregnancy, antiphospholipid syndrome or Child-Pugh C cirrhosis (rivaroxaban: also not Child-Pugh B); use LMWH or warfarin
- Worsening despite heparin: specialist IR options (transhepatic or transjugular thrombolysis or thrombectomy) in selected patients
- No thrombolysis with: recent surgery or trauma, active bleeding, cirrhosis with varices, recent stroke or intracranial haemorrhage, uncontrolled hypertension
- Peritonitis develops: laparotomy, resect only necrotic bowel, second look
- Then anticoagulation for 3 to 6 months (warfarin or LMWH; DOAC is an alternative); indefinite if unprovoked or a permanent risk factor
- Look for a cause: cirrhosis, cancer, myeloproliferative neoplasm, inflammatory disease, recent abdominal surgery; thrombophilia testing in selected patients
- Path rejoins step 12Shared downstream outcome
- NOMI
18Action Non-occlusive ischaemia (NOMI): restore gut perfusion
Patent vessels on CTA in a low-flow state; usually managed in ICU
- Treat the cause: shock, hypovolaemia, low cardiac output
- Optimise cardiac output; reduce vasoconstrictors where possible, but keep what is needed for perfusion pressure
- Measure bladder pressure. Abdominal compartment syndrome: urgent decompression laparotomy
- Consider catheter-directed intra-arterial vasodilator (papaverine or prostaglandin) into the SMA, with heparin
- Peritonitis, perforation or worsening: laparotomy and resect necrotic bowel
- Path rejoins step 12Shared downstream outcome
If No19Action CTA not diagnostic but suspicion remains: do not stop here
Early AMI and NOMI can be missed. Review the CTA with a senior radiologist and surgeon.
- Also look for other causes on CTA (for example aortic dissection, ruptured aneurysm, perforation, obstruction) and treat them
- Reassess often: repeat examination and lactate trend
- Critically ill patient in shock: consider NOMI; measure bladder pressure
- Peritonitis or clinical worsening: diagnostic laparotomy
- Persistent suspicion: repeat CTA or catheter angiography with the vascular team
20Outcome Reassess and escalate
Escalate at once if pain, lactate or organ function worsen
Guideline Source
ESVS 2025 Clinical Practice Guidelines on the Management of Diseases of the Mesenteric and Renal Arteries and Veins (Eur J Vasc Endovasc Surg 2025;70(2):153-218)
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Adults only. Evidence is mostly observational; open versus endovascular choice depends on local expertise.
- Lab tests cannot rule out AMI; do not let them delay CT angiography.
- Mortality stays high (about 30 to 70%), higher in NOMI.
Contraindicated Populations
Children (adult pathway)
Applicable Regions
AUEUUSGlobal
AU: No Australian AMI guideline. If no 24/7 vascular surgery and interventional radiology, transfer early through the local retrieval service.
EU: ESVS 2025 is the current European vascular surgery guideline for this condition.
US: Management principles are similar; follow local vascular surgery practice.
Version 2Next review: 2027-09-30
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Frequently Asked Questions
What is the Acute Mesenteric Ischemia Management (ESVS)?
The Acute Mesenteric Ischemia Management (ESVS) is a emergency clinical algorithm for Gastroenterology. It provides a structured decision tree to guide clinical decision-making, based on ESVS 2025 Clinical Practice Guidelines on the Management of Diseases of the Mesenteric and Renal Arteries and Veins (Eur J Vasc Endovasc Surg 2025;70(2):153-218).
What guideline is the Acute Mesenteric Ischemia Management (ESVS) based on?
This algorithm is based on ESVS 2025 Clinical Practice Guidelines on the Management of Diseases of the Mesenteric and Renal Arteries and Veins (Eur J Vasc Endovasc Surg 2025;70(2):153-218) (DOI: 10.1016/j.ejvs.2025.06.010).
What are the limitations of the Acute Mesenteric Ischemia Management (ESVS)?
Known limitations include: Adults only. Evidence is mostly observational; open versus endovascular choice depends on local expertise.; Lab tests cannot rule out AMI; do not let them delay CT angiography.; Mortality stays high (about 30 to 70%), higher in NOMI.. Individual patient factors may require deviation from these recommendations.
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