# Angiodysplasia and Heyde Syndrome

> Angiodysplasia and Heyde syndrome for NEET-PG Medicine: right-sided colonic bleeding, aortic stenosis link, acquired von Willebrand syndrome and treatment.

- Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/angiodysplasia-and-heyde-syndrome
- Exam / course: NEET-PG · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-15
- Last updated: 2026-10-15
- Reference basis: Harrison's Principles of Internal Medicine; Davidson's Principles and Practice of Medicine; Williams Hematology
- How to cite: "Angiodysplasia and Heyde Syndrome", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/angiodysplasia-and-heyde-syndrome

## Direct answer

Angiodysplasia is a degenerative vascular ectasia of the gut, most often in the right colon of older adults, causing occult or recurrent painless bleeding. Heyde syndrome is the association of colonic angiodysplasia with aortic valve stenosis, where the link is acquired von Willebrand syndrome from shear-induced loss of high-molecular-weight multimers. Replacing the stenotic valve usually resolves the bleeding.

## What you must remember

- **Site:** most lesions lie in the caecum and ascending colon, with occasional small bowel involvement and rarely the left colon.
- **Presentation:** occult bleeding causing iron deficiency anaemia, or painless recurrent haematochezia in older adults.
- **Heyde triad:** aortic stenosis, gastrointestinal angiodysplasia and acquired von Willebrand disease.
- **Acquired von Willebrand:** loss of high-molecular-weight multimers, with reduced von Willebrand factor activity and a normal platelet count.
- **Associations:** acquired von Willebrand syndrome also appears in myeloproliferative disorders and with mechanical circulatory support.
- **First test:** colonoscopy with a full examination of the colon, with capsule endoscopy for small bowel lesions if colonoscopy is negative.
- **Active bleeding:** CT angiography or catheter angiography localises a brisk bleed, and angiography can also embolise the lesion.
- **Treatment:** endoscopic coagulation with argon plasma or bipolar probes, octreotide for refractory bleeding, and aortic valve replacement in Heyde syndrome.

## How the valve causes the bleed

The mechanism explains both the association and the cure, and it is a favourite viva question. The steps below follow the chain from the stenotic valve to the bleeding lesion.

1. **High shear:** a stenotic aortic valve accelerates blood flow across the narrowed orifice, generating high shear stress.
2. **vWF unfolding:** the shear unfolds von Willebrand factor, exposing sites that are cleaved by the protease ADAMTS13, which is the main reason multimers are lost.
3. **Multimer loss:** the high-molecular-weight multimers are lost, so the platelet-adhesion function of von Willebrand factor falls.
4. **Vascular ectasia bleeds:** fragile angiodysplastic vessels in the colon then bleed easily, because haemostasis is impaired. The bleeding is typically slow and occult, though brisk haemorrhage can occur.
5. **Valve replacement:** removing the stenosis lowers shear, multimers recover, and the bleeding usually stops.
6. **Reassessment:** if bleeding persists, the lesion is treated endoscopically and the von Willebrand defect is re-examined. Recovery of haemoglobin and iron stores confirms that the bleeding has settled.

## Where the exam tries to catch you

The stem gives an elderly patient with anaemia and a murmur, and the trap is to chase only the gut.

- **Trap:** assuming iron deficiency means a left-sided lesion — **Correct:** angiodysplasia is typically right-sided, so the whole colon is examined.
- **Trap:** treating Heyde bleeding with iron alone — **Correct:** the cause is the stenotic valve, and correcting it addresses the acquired von Willebrand defect.
- **Trap:** assuming a normal platelet count excludes von Willebrand disease — **Correct:** a normal count does not exclude it, and the tests are von Willebrand factor activity, antigen and multimer analysis.
- **Trap:** operating first for diffuse angiodysplasia — **Correct:** endoscopic and medical therapy come first, and resection is reserved for focal lesions causing life-threatening bleeding.

## Frequently asked questions

### What is Heyde syndrome?

Heyde syndrome is the combination of aortic valve stenosis, gastrointestinal angiodysplasia and acquired von Willebrand syndrome. Shear stress across the stenotic valve destroys the high-molecular-weight multimers of von Willebrand factor, which predisposes to bleeding from the angiodysplastic colon.

### Which investigation first confirms colonic angiodysplasia?

Colonoscopy is the first investigation for colonic angiodysplasia, because it shows the characteristic flat, bright-red, fern-like lesions a few millimetres across. Capsule endoscopy is used when colonoscopy is negative and small bowel bleeding is suspected.

### What is the treatment for refractory angiodysplasia bleeding?

Octreotide is used for refractory angiodysplasia bleeding when endoscopic therapy fails or is not possible. It reduces splanchnic blood flow, and it is combined with endoscopic or angiographic treatment in difficult cases.

### Why does aortic stenosis cause bleeding in these patients?

Aortic stenosis causes bleeding by producing high shear stress that unfolds von Willebrand factor and removes its high-molecular-weight multimers. The result is an acquired bleeding tendency that makes angiodysplastic vessels bleed more readily.