Bronchial embolization

Papaverine, because of its general depressant effect on smooth muscle, has been used in doses of 30 to 60 mg, subcutaneously and intravenously, in peripheral thrombosis and embolism, acute myocardial infarction, angina pectoris, bronchial asthma, renal and biliary colic, and other conditions in which relaxation of smooth muscle is desired. However, the therapeutic effectiveness of papaverine is questionable, and there is no established indication for its use. 

The vasoconstrictor action of shed blood tested by perfusion of the rabbit ear is markedly decreased by heparin and this was known long before the identification of the vasoconstrictor activity as serotonin (5-hydroxytryp-tamine). Heparin inhibits the release of both 5-hydroxytryptamine and a polypeptide from platelets into plasma, and in vitro there is mutual antagonism between heparin and 5-hydroxytryptamine . Heparin effectively antagonizes the effect of serotonin on pulmonary vascular bed and bronchial wall musculature and prevents the symptoms of 5-HT release in pulmonary embolism, in the cardiopulmonary by-pass, in experimental burn injuries and in carcinoid tumour. 

Mai H, Rullon RMellot F,et al. (1999) Immediate and longterm results of bronchial artery embolization for life-threatening hemoptysis [see comment]. Chest 115 996-1001... 

IS.Uflacker R, Kaemmerer A, Picon PD, et al. (1985) Bronchial artery embolization in the management of hemoptysis technical aspects and long-term results. Radiology 157 637-644... 

Tomashefski JF, Cohen AM, Doershuk CF (1988) Longterm histopathologic follow-up of bronchial arteries after therapeutic embolization with polyvinyl alcohol (Ivalon) in patients with cystic fibrosis. Hum Pathol 19 555-561... 

Yoon W (2004) Embolic agents used for bronchial artery embolization in massive haemoptysis. Expert Opin Phar-macother 5 361-367... 

Bronchial artery embolization was first described in the literature in the 1970s by Remy [1], and over time it has become a well established treatment for patients with (massive) hemoptysis [2-5]. Technical improvements in both catheters and embolizing agents have attributed to the increase of the safety of the procedure and it s applicability. 

In this chapter the pathophysiology and etiology of hemoptysis will be discussed, as well as the diagnostic work-up of patients suffering from severe bronchial bleeding. Anatomy of bronchial arterial supply will be described. The techniques, pitfalls, complications and results of bronchial artery embolization will be discussed. 

Communications between bronchial arteries and systemic vessels are ubiquitous, and can sometimes complicate an embolization procedure. The most commonly seen communication is that of a right intercostobronchial trunk with an anterior medullary artery that contributes to the vascular supply of the spinal cord through the anterior spinal artery. The anterior medullary arteries have a characteristic hairpin configuration, and follow a course... 

In the future the need for flush aortography prior to and after embolization may be obviated, when the use of multi-detector row CT becomes more and more common. There are indications that the use of thin-section CT scanning reduces procedural time, as well as the potential iatrogenic risks of a selective search for ectopic bronchial or abnormal non-bron-chial systemic arteries [19]. 

Table 16.2 lists the materials most commonly used for bronchial artery embolization. 

Various embolic agents can be employed for bronchial artery embolization, and include gelatin sponge, microspheres and coils. 

Stainless steel or platinum coils and detachable balloons are rarely used as aprimaryembolicagentinbron-chial artery embolization. Although these can be used to occlude a pathologic bronchial artery efficiently, use of coils predudes repeat embolization, which is often needed as patients are prone to distal collateralization (Fig. 16.21) [43,44]. The primary indication for use of coils is in patients with a bronchial artery aneurysm. Secondly, in cases where a superselective position of a (micro) catheter cannot be reached, coils can be used to protect a normal distal vascular territory against inadvertent embolization [25]. 

Thrombin injection into the bronchial artery has been described, and has a theoretical advantage in patients where tortuosity of the target artery precludes superselective catheterization [45]. However, given the rather unpredictable behavior, and risk of peripheral embolization, this agent has not gained wide acceptance, the same as using absolute alcohol as an embolic agent. 

Bronchial artery embolization is highly effective in the treatment of acute hemoptysis. Short-term... 

The underlying disease is also of importance patients with chronic tuberculosis more frequently suffer from recurrent hemoptysis, since the development of non-bronchial systemic collaterals is more extensive [33, 54]. However, repeat embolization in such patients, including treatment of non-bronchial collaterals often leads to satisfactory results [32, 55-57]. 

Finally, operator experience in bronchial artery embolization is of crucial importance in achieving high success and low complication rates. Given the low incidence of acute massive hemoptysis, the risk that each patient represents a new learning experience is not unimaginable [38], and therefore bronchial artery embolization should only be performed by skilled operators (at least five to ten cases a year). 

Rare complications as have been reported in literature are aortic and bronchial necrosis [58], bronchial stenosis [59], unilateral diaphragmatic paralysis [60], pulmonary infarction (especially in patients who have suffered pulmonary artery embolism), left main bronchial-esophageal fistula [61], and non-target embolization (colon, coronary and cerebral circulation) [62]. Especially the newer spherical embolic materials (tris-acryl gelatin) can traverse from the bronchial into the pulmonary circulation, and then through unoccluded pulmonary arteriovenous malformations into the systemic circulation [41]. 

Bronchial artery embolization is the treatment of choice in acute hemoptysis. 

The most commonly occurring complication encountered after bronchial artery embolization is (transient) chest pain, being reported in 24% up to 91% of cases. This is probably related to ischemia of embolized branches, and can be severe when intercostal branches are inadvertently embolized. Pleural pain can be avoided by using superselec-tive embolization techniques, with or without the use of large particles. The second most common complication is dysphagia, caused by embolization of esophageal branches, with a reported occurrence from 0.7% to 18.2% [30]. Spontaneous resolution of symptoms usually occurs. 

The most devastating complication is spinal cord ischemia, that has been reported to occur in 1.4%-6.5% of patients treated with bronchial artery embolization [9,30,39]. The occurrence of this complication can be reduced by using a superselective embolization technique, performing regular control angiograms before and after administration of embolic agents as has been described above. 

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