Haemoptysis - what an interventional radiologist needs to know

Haemoptysis is a common medical condition frequently encountered in hospitals, particularly in departments of chest medicine and thoracic surgical units. Most haemoptysis episodes are small to moderate and self-limiting. However, in about 5% of cases, they can be massive and life-threatening, which usually denotes a volume of blood loss ranging from 100ml to 1000ml/24-48 hours.

Causes and source of bleeding: worldwide, the most common causes of massive, life-threatening haemoptysis are tuberculosis (TB), bronchiectasis, aspergilloma/mycetoma, cancer, and cystic fibrosis. In about 90% of cases, the source of bleeding is the bronchial artery, in 5% cases, it is non-bronchial systemic arteries such as internal mammary (thoracic), branches from subclavian or intercoastal, phrenic arteries etc., whereas in about 5% of cases, bleeding occurs in the pulmonary artery branches.

Danger of choking: The danger of severe haemoptysis is not due to the volume of blood loss, but rather the risk for asphyxiation, and it is commonly accompanied by cardiovascular collapse. As the volume of the bronchial tree is only about 150ml, a bleeding of 100ml may be enough to inundate the bronchial tree and asphyxiate the patient. Therefore, severe haemoptysis is a medical emergency and therapy must be expedited as quickly as possible. Initial treatment is the stabilization of the patient to prevent asphyxiation.

Diagnosis: The initial diagnostic modality can be a chest radiograph (CXR). However, it is though not specific and has a wide variation of efficacy in detecting the region of bleeding (range about 30-80%). Where CT scanning is not readily available for life threatening hemoptysis, fiberoptic bronchoscopy is the first line of management, also in a rapidly bleeding, unstable patient who will need stabilization prior to transport. MDCT (multidetector CT) and bronchoscopy are similar in efficacy in detecting the site of bleeding (~70-75%), however, CT is superior in detecting the underlying cause of bleeding compared to bronchoscopy (77% vs 8%). Even a non-contrast-enhanced MDCT can identify the cause and location of bleeding in about 80-100% of cases. Contrast-enhanced CT can be advantageous in patients with massive haemoptysis, because of its ability to precisely delineate bronchial and non-bronchial systemic arterial blood supply and provide additional information about vascular anatomy. Active ongoing bleeding is seen only in a small percentage (10-15%) of patients. However, the following signs are good indicators of vascular lesion both in CT angiography (CTA) and DSA (digital subtraction angiography): hypervascularity of lung and/or peribronchial region, hypertrophic bronchial or non-bronchial arteries, main bronchial artery diameter > 2mm, A-V shunts, aneurysm or pseudoaneurysm. Where non-bronchial systemic arteries are involved, pleural thickening of >3mm adjacent to parenchymal abnormality and/or extrapleural fat-hypertrophy including enlarged vascular structure can be seen.

Because of its higher diagnostic yield, CT can probably replace bronchoscopy as a first-line investigational approach in a patient with severe haemoptysis.

Anatomy: Commonly, bronchial arteries arise from the aorta between T3-T8, but most frequently between T5–T6. The most common patterns of bronchial artery origins are – 1. single right intercosto-bronchial trunk and a single left bronchial artery (30.5%); 2. Right intercosto-bronchial trunk, giving rise to the right bronchial artery and a second common trunk form which right and left bronchial arteries arise (25%); 3. A right intercosto-bronchial trunk giving rise to a right bronchial artery and two bronchial arteries on the left (12.5%).

Bronchial artery embolization (BAE): Bronchial artery embolization are now widely used, often as a first-line treatment. Usually, a smaller recurved catheter (4F or 5F Sidewinder/Mikaelsson) is used to engage the bronchial artery for stabilization followed by a coaxial 2.0F or 2.8F microcatheter for superselective catheterization. Previously, non-calibrated PVA particles of about 350-500 µm were used, but they are currently being replaced by more uniformly calibrated particles of 300-900 µm. Gelfoam can be used as a supplement, but not as a sole embolizing agent. Microcoils are mostly reserved for patients with A-V shunting or aneurysm/pseudoaneurysm or where there is a risk of spinal ischemia. Particles <300 µm are not recommended to avoid severe tissue ischemia, particularly of bronchi, esophagus, and vasa vasorum to the aorta and pulmonary artery. Liquid embolics like NBCA (N-butyl cyanoacrylate) and Onyx are more effective in haemoptysis control than particles, but require experience for their delivery. Success of BAE is 60-90%, but recurrence is common. Repeat BAE is possible with good outcome. Complications of BAE include chest pain and dysphagia which are self-limiting. Severe complications such as spinal ischemia due to non-target embolization, are rare, but can occur in up to 1.4 – 6.5% of cases.