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Health condition · Clinically reviewed

Intestinal ischaemia, from acute emergency to chronic intestinal angina.

A time-critical vascular problem in the bowel. The right imaging, the right team and the right revascularisation, in the right order, save lives and bowel.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against BSG, AVS and peer-reviewed sources you can see at the end of this page.

  • 03

    Current for 2026

    Reflects modern UK practice including CT mesenteric angiography, endovascular stenting and specialist-commissioned emergency care.

Key facts

Intestinal ischaemia at a glance.

The essentials, in plain English - what it is, how it presents, how it is imaged and how it is treated in the UK today.

  • What it is

    Inadequate blood supply to the small or large bowel - a spectrum from sudden emergency to slow-burning postprandial pain.

  • Acute mesenteric

    An emergency - sudden severe abdominal pain often out of proportion to examination, with a mortality above 50 per cent if delayed.

  • Four acute causes

    Arterial embolic (often atrial fibrillation), arterial thrombotic, non-occlusive (shock) and venous thrombosis.

  • Chronic mesenteric

    Postprandial pain, weight loss and food fear - so-called intestinal angina from atherosclerotic mesenteric vessels.

  • Gold standard imaging

    CT mesenteric angiography confirms the diagnosis, identifies the vessel and guides treatment.

  • Modern treatment

    Resuscitation, anticoagulation, endovascular stenting or thrombectomy, and open surgery when bowel is threatened.

Why this guide matters

The clock decides the outcome.

Intestinal ischaemia is quiet at first and catastrophic at the end. The three points below shape everything else on this page.

  • Time is bowel

    Every hour of delay in acute mesenteric ischaemia costs viable bowel and lives. Suspicion and imaging are everything.

  • Imaging beats intuition

    CT mesenteric angiography is the gold-standard test - it distinguishes embolic, thrombotic, non-occlusive and venous disease.

  • Modern revascularisation

    Endovascular stenting, thrombectomy and thrombolysis, alongside open surgery, mean many more patients keep their bowel and their independence.

How the diagnosis is made

From first suspicion to a clear plan.

The steps a UK emergency team, vascular surgeon and radiologist will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    Vascular and cardiac history

    Atrial fibrillation, previous embolism, atherosclerosis, hypercoagulable states and oral contraceptive use all shape the risk profile.

  2. 02

    Assessing

    The tell-tale story

    Sudden severe abdominal pain out of proportion to the examination in acute cases, or postprandial pain and food fear in chronic disease.

  3. 03

    Assessing

    Examination and peritonism

    Early findings can be minimal - peritonism, distension and shock are late and ominous features.

  4. 04

    Confirming

    Bloods and lactate

    Full blood count, lactate, arterial gases and clotting - a rising lactate raises suspicion but a normal one does not exclude ischaemia.

  5. 05

    Confirming

    CT mesenteric angiography

    The gold-standard investigation for acute mesenteric ischaemia - commissioned as an emergency in every UK vascular network.

  6. 06

    Confirming

    Endoscopy for colonic ischaemia

    Colonoscopy with biopsy is often used for suspected ischaemic colitis, once acute mesenteric ischaemia has been excluded.

  7. 07

    Planning

    Vascular and colorectal MDT

    A specialist-commissioned MDT of vascular surgery, colorectal surgery, interventional radiology and emergency medicine sets the plan.

Typical timeline: acute cases are decided in hours, chronic cases in weeks.

Symptoms

What intestinal ischaemia looks like.

The classic acute picture of severe pain out of proportion, and the slower chronic pattern of pain after meals and weight loss.

  • Sudden severe abdominal pain

    The hallmark of acute mesenteric ischaemia - abrupt, central, out of proportion to what the examining hand can feel.

  • Postprandial pain

    Pain 15 to 60 minutes after eating in chronic mesenteric ischaemia, giving the classic pattern of intestinal angina.

  • Weight loss and food fear

    People eat less to avoid the pain - unintentional weight loss is common and often the first clue.

  • Nausea, vomiting and diarrhoea

    Non-specific gastrointestinal upset accompanies both acute and chronic disease, and can delay diagnosis.

  • Rectal bleeding

    Blood or bloody diarrhoea suggests mucosal ischaemia, especially in ischaemic colitis and later acute ischaemia.

  • Shock and peritonitis

    Late features of transmural infarction - hypotension, tachycardia and a rigid abdomen mark a surgical emergency.

  • Malabsorption

    Chronic disease can cause fat malabsorption, deficiency of fat-soluble vitamins and progressive nutritional decline.

  • Red flag - pain out of proportion

    Severe pain with a soft abdomen in an older person with atrial fibrillation is acute mesenteric ischaemia until proven otherwise.

Treatment

How intestinal ischaemia is treated in the UK.

Immediate resuscitation and anticoagulation, then endovascular or open revascularisation and, where needed, resection of non-viable bowel.

  • Resuscitation

    Intravenous fluids, oxygen, correction of acidosis and broad-spectrum antibiotics form the foundation of acute care.

  • Systemic anticoagulation

    Therapeutic heparin is started as soon as acute mesenteric ischaemia is suspected, unless there is a clear contraindication.

  • Endovascular thrombolysis

    Interventional radiology can deliver clot-busting drugs directly into the mesenteric vessels in selected embolic cases.

  • Mesenteric artery stenting

    Endovascular stenting reopens the diseased vessel and is the modern first-line option for many chronic and some acute cases.

  • Open thrombectomy and bypass

    Surgical revascularisation remains vital where endovascular access fails or where non-viable bowel needs simultaneous resection.

  • Bowel resection

    Non-viable, infarcted bowel is removed at laparotomy - a second-look operation is often planned 24 to 48 hours later.

  • Anticoagulation for venous cases

    Mesenteric venous thrombosis is usually managed with prolonged anticoagulation and a thorough thrombophilia workup.

  • Nutrition and follow-up

    Dietitian input, cardiovascular risk optimisation and lifelong follow-up - short bowel syndrome is a real long-term risk after major resection.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, vascular surgeon or gastroenterologist knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • British Society of Gastroenterology (BSG). Guidance on acute and chronic mesenteric ischaemia.

  • Association of Vascular Surgery (AVS) and Vascular Society for Great Britain and Ireland.

  • European Society for Vascular Surgery. Clinical practice guidelines on the management of mesenteric ischaemia.

  • NICE. Guidance on atrial fibrillation, anticoagulation and cardiovascular risk optimisation.

Red flags

When intestinal ischaemia needs urgent attention.

Some presentations demand hospital assessment the same day - and, where acute mesenteric ischaemia is suspected, within the hour.

  • Sudden severe abdominal pain

    Especially in an older person with atrial fibrillation, recent embolism or vascular disease - treat as acute mesenteric ischaemia until proven otherwise.

  • Pain out of proportion to examination

    The classic acute presentation. A soft abdomen does not exclude ischaemia and can be the most treacherous sign of all.

  • Rising lactate and metabolic acidosis

    A worsening lactate in an unwell patient with abdominal pain demands immediate senior review and mesenteric imaging.

  • Peritonitis and shock

    Late features that suggest transmural infarction - straight to theatre for laparotomy after resuscitation.

  • Rectal bleeding with ischaemic pattern

    Blood or bloody diarrhoea in an at-risk patient warrants urgent assessment for ischaemic colitis or acute mesenteric disease.

  • Progressive weight loss with meal pain

    Chronic mesenteric ischaemia is easily missed - unexplained weight loss and food fear should prompt vascular referral.

  • Postoperative or critically ill patient

    Non-occlusive mesenteric ischaemia is a silent complication of shock, vasopressors and cardiac surgery - a high index of suspicion saves lives.

  • Suspected mesenteric venous thrombosis

    A subacute presentation in someone with a hypercoagulable state, malignancy or oral contraceptive use deserves early cross-sectional imaging.

  • Short bowel syndrome after resection

    Major bowel loss after ischaemia leads to lifelong nutritional needs - long-term specialist follow-up is essential.

Living with it

A serious condition, with real recovery ahead.

Four things that make the biggest difference in the months after diagnosis - realistic recovery, nutrition, cardiovascular prevention and staying in touch with the team.

A quiet reminder

Recovery is a marathon, not a sprint.

Small, steady progress with meals, activity and cardiovascular prevention beats any short-term push.

  1. 01 Recovery

    Expect a long tail after acute disease

    Even after successful revascularisation, appetite, weight and stamina take months to return - be patient with yourself.

  2. 02 Nutrition

    Work with a dietitian

    Small, frequent meals, careful fat intake and vitamin monitoring make a real difference, especially after any bowel resection.

  3. 03 Prevention

    Treat the vessels, not just the bowel

    Blood pressure, cholesterol, diabetes and smoking are the levers - lifelong cardiovascular risk optimisation protects every vascular bed.

  4. 04 Follow-up

    Stay connected to the team

    Regular reviews with vascular surgery, gastroenterology and your GP catch problems early and keep the plan up to date.

Frequently asked

Everything we get asked about intestinal ischaemia.

Quick answers on causes, symptoms, imaging, treatment and long-term outlook.

  • What is intestinal ischaemia?

    Intestinal ischaemia means the bowel is not getting enough blood. It ranges from a slow, chronic reduction that causes postprandial pain to a sudden, complete blockage that is a surgical emergency. The four main patterns are acute mesenteric ischaemia, chronic mesenteric ischaemia, ischaemic colitis and median arcuate ligament syndrome.

  • How is acute mesenteric ischaemia recognised?

    The classic story is sudden severe abdominal pain that seems out of proportion to what the doctor finds on examination, often in an older person with atrial fibrillation, previous embolism or diffuse vascular disease. Nausea, vomiting, diarrhoea and rectal bleeding can follow, and shock or peritonitis appear late. It is an emergency, and CT mesenteric angiography is the gold-standard test.

  • What causes acute mesenteric ischaemia?

    About half of cases are arterial emboli, usually from atrial fibrillation or endocarditis. Others are arterial thrombosis on top of atherosclerosis, non-occlusive ischaemia in shock or after cardiac surgery, and mesenteric venous thrombosis in people with hypercoagulable states, malignancy or oral contraceptive use.

  • What does chronic mesenteric ischaemia feel like?

    People describe a dull, cramping pain 15 to 60 minutes after eating, called intestinal angina. Meals become something to fear, weight falls and malabsorption can set in. It is usually caused by atherosclerosis in the mesenteric arteries and responds well to endovascular stenting or open bypass.

  • How is intestinal ischaemia treated?

    Acute disease needs immediate resuscitation, antibiotics and anticoagulation, followed by endovascular thrombolysis, thrombectomy or stenting, and emergency surgery when bowel is non-viable. Chronic disease is usually treated by endovascular stenting or open bypass. Venous cases are managed with prolonged anticoagulation. Everyone benefits from cardiovascular risk optimisation and dietitian support.

  • What is the long-term outlook?

    The prognosis depends on how quickly acute disease is recognised and treated, and on how much bowel remains viable. Early diagnosis and modern endovascular techniques have improved outcomes, but delayed care still carries a mortality above 50 per cent. Long-term follow-up focuses on nutrition, recurrence, cardiovascular risk and, where relevant, short bowel syndrome.

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