Bronchial artery embolization

Bronchial artery embolization (BAE) is an angiographic interventional procedure and endovascular technique developed to stop bleeding in acute severe or chronic increasing hemoptysis ^1-4.

History and etymology

The development of bronchial artery embolization techniques has significantly revolutionized the approach to patients with massive hemoptysis and was first described by the French radiologist Jacques Rémy and his colleagues in 1973 ^5-6.

Indications

Indications for bronchial artery embolization include ¹:

• hemoptysis causing respiratory distress or significant airway compromise

• recurrent episodes of bleeding (three or more episodes per week with ≥100 mL of blood)

• slowly increasing or chronic hemoptysis ⁷

Contraindications

Contraindications for bronchial artery embolization include ¹:  

An absolute contraindication is branches arising from bronchial or intercoastal arteries supplying the heart, spinal cord or brain.

A relative contraindication is pulmonary artery stenosis because bronchial arteries may provide collaterals and have a significant role in pulmonary perfusion.

Other contraindications include those for angiography in general, such as uncorrectable coagulopathy, renal failure, and severe contrast allergy ⁸.

Procedure

Preprocedural evaluation

Apart form a thorough clinical evaluation, laboratory valus and the assessment and grading of hemoptysis pre-procedural evaluation usually includes a chest x-ray, thoracic CTA and bronchoscopy ^1,2.

In addition a brief neurological examination should be conducted before the procedure and repeated throughout the embolization process ⁴.

Technique

The technique might include the following steps ⁴:

• five or six French sheaths are typically utilized for the insertion of selective catheters

• using reverse-curved catheters (Mikaelson, Simmons I, SOS Omni) or forward-looking catheters (such as Cobra, HIH, and RC)

• the left mainstem bronchus serves as a convenient fluoroscopic landmark for locating the bronchial arteries

• before any embolization procedure, it is necessary to conduct a selective bronchial arteriogram

• if successful cannulation is not achieved promptly, a thoracic aortogram should be performed

• abnormal angiographic findings that suggest the site of bleeding include tortuosity, hypervascularity, hypertrophy, extravasation, aneurysms, and bronchial artery to the pulmonary artery or vein shunting

• the injection of the bronchial artery may cause coughing, although this is much less common with newer nonionic and iso-osmolar contrast agents

• if the site of hemorrhage is known, all abnormal bronchial arteries supplying that region should be embolized

• different embolic agents have been utilized, such as polyvinyl alcohol (PVA) particles ranging in size from 300 to 500 μm, other microspheres gelatin sponge, thrombin, coils and glue ^1-4   

Recurrent hemoptysis after successful bronchial artery embolization is common in chronic inflammatory lung disease. The offending vascular supply in this situation may include a recanalized bronchial artery, a bronchial artery that was not previously embolized (aberrant or non-aberrant), or non-bronchial system collateral. Systemic collaterals with nonbronchial origin include branches of the thyrocervical trunk, subclavian artery, internal mammary artery, inferior phrenic artery, and axillary artery ⁴.

Complications

The most common complications include transient chest or back pain and dysphagia ² as well as postembolization syndrome observed in up to 30% of cases or more ^2,9-12.

Major complications include non-target embolization including lower extremity ischemia, ischemic colitis bronchiooesophageal fistula and bronchial infarction, as well as spinal ischemia and stroke ^3,4.

Neurologic complications including spinal cord ischemia with transient and/or permanent paraparesis or paraplegia as well as transient ischemic events, stroke or cortical blindness are considered rare complications, which have been reported in less than 5% of cases ².

Outcomes

Immediate clinical success rates have been reported to range from 70% to 99% ².

Despite apparently adequate embolization therapy, the recurrence of hemoptysis remains a significant challenge due to the chronic nature of the underlying disease processes. Reported long-term recurrence rates range from 10% to 58% ^{2, 9,13-15}.