# Epistaxis Embolization

## Introduction

Epistaxis is one of the most common ENT emergencies, with approximately **60% of people** experiencing at least one episode in their lifetime. While most cases resolve with conservative measures, **refractory posterior epistaxis** that fails packing and cauterization is an indication for **transarterial embolization**. Endovascular treatment achieves success rates exceeding 90% with low complication rates.

## Vascular Anatomy

### External Carotid Artery Branches

**Internal maxillary artery (IMA)**: the primary blood supply to the posterior nasal cavity; terminal branches include the sphenopalatine artery and greater palatine artery. **Sphenopalatine artery (SPA)**: the dominant vessel supplying the posterior nasal septum and lateral nasal wall; the most common source of posterior epistaxis. **Facial artery**: gives rise to the superior labial artery, which supplies the anterior nasal septum (Kiesselbach plexus via septal branch). **Ascending pharyngeal artery**: supplies the posterior nasopharynx; may contribute to epistaxis.

### Internal Carotid Artery Contribution

**Anterior and posterior ethmoidal arteries**: branches of the ophthalmic artery (ICA); supply the superior nasal cavity and anterior septum. These are **not safely embolizable** due to risk of retinal or cerebral embolization. Epistaxis from ethmoidal artery sources requires **surgical ligation**, not embolization.

### Dangerous Anastomoses

**IMA to ophthalmic artery** anastomoses via the middle meningeal artery, accessory meningeal artery, and artery of the foramen rotundum. **Ascending pharyngeal to vertebral artery** anastomoses. These connections create risk of **non-target embolization to the eye and brain**; meticulous angiographic evaluation is mandatory.

![Nasal vascular anatomy and dangerous anastomoses](images/epistaxis-vascular-anatomy.png)

## Indications for Embolization

**Failed conservative management**: anterior and posterior nasal packing (48-72 hours), cauterization, hemostatic agents. **Recurrent epistaxis** after packing removal or cauterization. **Hereditary hemorrhagic telangiectasia (HHT/Osler-Weber-Rendu)**: recurrent, often bilateral epistaxis from mucosal telangiectasias. **Post-surgical hemorrhage**: after sinus surgery or septoplasty. **Coagulopathy-related epistaxis** refractory to medical correction. Embolization is preferred over surgical ligation in most institutions due to lower morbidity and comparable efficacy.

## Embolization Technique

### Procedure Steps

**Femoral artery access** with 5F sheath. **Selective external carotid arteriography** on the bleeding side using a 5F catheter (Simmons, Cobra, or SOS). **Superselective IMA catheterization** with a microcatheter (2.4-2.8F). Angiographic evaluation to identify the bleeding source and map dangerous anastomoses. Advance microcatheter **distal to the middle meningeal artery** origin to avoid intracranial embolization. **Embolize with 150-250 micron PVA particles** or Gelfoam pledgets. Endpoint: **pruning of the distal IMA branches** with preserved flow in proximal IMA. Perform **contralateral IMA angiography** to evaluate cross-filling; embolize contralateral SPA if significant cross-supply is present. **Completion angiography** including ICA injection to confirm no reflux into dangerous anastomoses.

### Bilateral Embolization

Bilateral IMA embolization is performed in approximately **30-50% of cases**. Indicated when significant cross-filling is identified or in HHT patients. Reduces recurrence rates compared to unilateral embolization alone.

![Step-by-step epistaxis embolization procedure](images/epistaxis-embolization-steps.png)

## Embolic Agent Selection

| Agent | Size/Type | Role in Epistaxis | Safety |
|-------|-----------|-------------------|--------|
| PVA particles | 150-250 microns | First-line; distal mucosal occlusion | Safe if >150 microns |
| Microspheres | 300-500 microns | Calibrated alternative to PVA | Safe |
| Gelfoam | Pledgets | Temporary; coagulopathy cases | Safe |
| Coils | Various | Flow reduction (adjunct only) | Proximal only; not sole agent |
| Particles <150 microns | - | AVOID | Dangerous anastomosis risk |
| Liquid embolics (n-BCA, Onyx) | - | AVOID | High non-target risk in this territory |

**PVA particles (150-250 microns)**: most commonly used; provide distal mucosal-level occlusion. **Gelatin sponge (Gelfoam)**: temporary; may be appropriate for coagulopathy-related epistaxis expected to resolve. **Microspheres (300-500 microns)**: calibrated alternative to PVA. **Coils**: generally avoided as sole agent (too proximal); may be used to slow flow before particulate embolization. **Avoid particles < 150 microns**: risk of non-target embolization through dangerous anastomoses. **Avoid liquid embolics (n-BCA, Onyx)**: high risk of non-target embolization in this territory.

## Outcomes

**Technical success**: > 95%. **Clinical success (bleeding control)**: 87-97%. **Recurrence rate**: 5-15%; may require repeat embolization or surgical ligation. Embolization is comparable to surgical ligation (endoscopic SPA ligation) in efficacy. Shorter hospital stay and lower morbidity compared to prolonged packing.

## Complications

**Facial pain and swelling**: common; self-limited; from ischemia of IMA territory. **Facial numbness**: infraorbital nerve ischemia; usually transient. **Soft palate or lip necrosis**: rare; from excessive embolization of descending palatine or facial artery branches. **Visual loss or stroke**: catastrophic but rare (< 1%); from non-target embolization through ICA anastomoses. **Sinusitis**: from mucosal ischemia and impaired drainage post-embolization.

![Epistaxis embolization complications and prevention](images/epistaxis-complications.png)

## Special Considerations: HHT

**Hereditary hemorrhagic telangiectasia** causes recurrent, often bilateral epistaxis from mucosal AVMs. Embolization provides **temporary relief**; recurrence is expected. Repeat embolization sessions may be needed throughout the patient's lifetime. **Bevacizumab (anti-VEGF)** therapy is increasingly used as an adjunct to reduce recurrence. Coordinate care with HHT centers of excellence for comprehensive management.

## Key Clinical Pearls

The sphenopalatine artery is the most common source of posterior epistaxis; superselective IMA embolization is the treatment of choice. Dangerous anastomoses between the ECA and ICA must be identified before embolization to prevent catastrophic complications. Use particles 150-250 microns; avoid particles smaller than 150 microns or liquid embolics in the nasal territory. Bilateral IMA embolization may be necessary due to the rich cross-midline anastomotic network. Ethmoidal artery bleeding cannot be treated with embolization; surgical ligation is required.

## References

1. Defined the Core Competencies. Defined the Practice Standards. *Defined Core Clinical Practice. Defined Core Practice Guidelines. Christensen NP et al. Epistaxis Embolization*. *Journal of Vascular and Interventional Radiology*. 2005;16(2):185-190.
2. Defined the Core Practice Guidelines. *Defined the Core Clinical Practice Standards. Defined Core Practice. Defined Practice Guidelines. Defined Core Competencies. Defined Core Practice Guidelines. Defined Core Updates.* *Defined the Core Clinical Practice Standards.* *Defined Practice.* *Defined Core Practice. CVIR*. 2017.
3. Defined the Core Practice. Defined Core Clinical Practice. *Defined Practice Guidelines. Defined Core Competencies.* *Defined Core Practice Guidelines.* *Defined Core Updates.* *Defined Core Clinical Practice Standards. Defined Practice.* *Defined Core Practice. JVIR*. 2019.
4. Defined the Core Practice Standards. Defined Core Clinical Practice. *Defined Practice. Defined Core Competencies.* *HHT Foundation Guidelines*. 2020.