13th Annual Global Embolization Symposium & Technologies
Purpose : Massive hemoptysis is most feared of all respiratory emergencies and can have a variety of underlying causes. Common etilogies include tuberculosis (TB), post-tubercular sequelae, bronchiectasis, and aspergilloma. In 90% of cases, the source of hemoptysis is bronchial circulation. Despite high recurrence rates, bronchial artery embolization (BAE) remains first-line treatment in management of hemoptysis.
Material and Methods : Materials and Methods
The Institutional Research and Ethical Committee approved this retrospective study that included cases of bronchial artery embolization referred to Department of Radiology between July 2017 to December 2018. Written informed consent prior to procedure was obtained from all of the subjects. A total of 50 patients, in an age range of 19 to 62 years, comprising 32 males and 18 females comprised the study group. Of the total 50 patients, 40 patients had active / reactivation of tuberculosis. 4 patients were detected to have aspergillosis, 1 had lung malignancy. There were one patient each of bronchial varices (Figure 1) and pulmonary hamartoma. In three patients, etiology could not be ascertained.
The bronchial and pulmonary arteries in combination form the blood supply to the lungs, wherein pulmonary artery is responsible for approximately 99% of perfusion. Bronchial arteries supply the bronchi, lung interstitium, in addition also contribute to supply of posterior mediastinum, vagus nerve, trachea and esophagus. The elaborate knowledge of anatomy and variability is important to minimize the risk of otherwise inadvertent complications.
Bronchial arteries typically arise from descending thoracic aorta between T3-T8 vertebral bodies. Majority (~70%) of the times they arise at T5-T6 vertebral level and left main bronchus forms an important landmark on fluoroscopy. Various anatomic permutations have been described in literature regarding origin and branching pattern of bronchial arteries arising from the aorta, of which the classical four configurations were illustrated by Cauldwell et al. Type 1 and Type 2 configurations are comprised of a solitary right bronchial artery arising from an intercostobronchial trunk in conjunction with two and single left bronchial arteries respectively. Type 3 configuration has two bronchial arteries on either side, one of the right bronchial artery arising in conjunction with an intercostobronchial trunk. In type 4, there are two bronchial arteries on right side, of which one arises from an intercostobronchial trunk with a solitary left bronchial artery. (Figure 2) Other less commonly reported configuration is the presence of a common trunk of which arises one bronchial artery on either side.[2, 7] In agreement to the available literature, our experience also suggests type 1 (n=23; 46%) as the most frequent observation, but it was followed closely by presence of a common arterial trunk (n=19; 38%). Type 2 (n=5; 10%) and type 3 (n=3; 6%) permutations were very infrequently encountered. Non bronchial systemic feeders and aberrant bronchial vessels are not infrequent findings in diseased lung and when present, their embolization is necessary to achieve good clinical results. They have always been a concern to interventionists when doing a pre procedural evaluation. These may arise from almost any thoracic and abdominal arteries, most common being subclavian, internal mammary, thyrocervical and superior intercostals arteries. It becomes essential to differentiate bronchial from systemic collaterals through close inspection of the relationship of the vascular course with that of the bronchial tree.. Both ectopic and orthotopic bronchial arteries follow the course of the associated bronchi, on the contrary systemic nonbronchial collateral arteries are never seen joining the bronchial tree. In the present study, we found ectopic bronchial arteries in 24% (n=12), non bronchial systemic collaterals in 10% (n=5) and presence of bronchopulmonary shunts in 14% (n=7) cases. (Figure 3)
Anterior spinal artery courses along the ventral surface of the cord and receives supply from segmental medullary arteries. Classically, these are described to have “hairpin” configuration on angiography. The artery of Adamkiewicz, arising from an intercostal artery is most commonly seen at T8–L1 vertebral level. It was encountered in 6% (n=3) cases in the present study and non target embolization was successfully avoided in two of the three cases.
A comprehensive evaluation of symptoms, cause, extent of lung involvement and thorough investigation of culprit circulation prior to embolotherapy is of utmost importance. Grading of hemoptysis into mild, moderate and severe has been differently described in literature by various authors depending upon the volume and duration of bleeding. [9, 10, 11] It is categorised as mild when hemoptysis is less than 100 ml/day or less than 50 ml/ episode, moderate when there is a single event of 100–300 ml/day or >3 bouts of more than 100 ml/day in one week. Severe is hemoptysis of more than 300 ml/day or any amount, leading to more than 1g/dL hemoglobin drop or more than 5% hematocrit drop. Being a tertiary care health center, we had relatively skewed case distribution with more number of cases of moderate-massive hemoptysis (n=40; 80%) undergoing bronchial artery embolization compared to only 20% (n=10) cases presenting with mild hemoptysis.
The utility of pre procedure diagnostic work up with CT angiography (CTA) or fibre optic bronchoscopy (FOB) has been reiterated in literature by various authors. Whereas results of both CTA and FOB are comparable in lateralizing of bleeding, CTA fares better in being more informative about cause, extent of lung involvement and presence of aberrant bronchial and systemic non bronchial circulation.[2, 9, 12-14] We were able to perform CTA in nearly all cases except two those presented with life threatening hemoptysis. Good clinical outcomes observed in the present study can be attributed to CTA done prior to procedure. In 26% (n=13) cases, responsible circulation could not be detected on flush aortogram, however thorough search made on the basis of CTA did reveal collateral circulation that required embolization. (Figure 4) A few other authors have also discussed the importance of comprehensive search and complete embolization of bronchial as well as non bronchial circulation during the first session itself. [3, 9, 13-22]
These days many routes of endovascular acces have been described and widely practiced.We preferred transfemoral route for entry in all the patients.
Catheter choice and tip position-
A 5 French angiographic sheath (Boston Scientific, Boston, MA, USA) was placed in the common femoral artery. Through the sheath, a 4-French Slip-cath Beacon tip Cobra catheter (Cook Medical, Bloomington, IN, USA) was used to catheterize the orthotopoic bronchial arteries which were cannulated around the region of carina/left main bronchus in the anterior angulation. When cannulation with Cobra catheter was not possible use of SIM-1 (Simmons) or Shepherd hook (Boston Scientific, Boston, MA, USA) catheters was made. After catheterization of bronchial artery an angiogram (2 frames per second) was performed using iobitridol (350mg/ml Xenetix, Guerbet, France) to identify the abnormal (>2mm, hypertrophied and tortuous course) bronchial arteries. Following the identification and affirmation of abnormal bronchial artery it was superselectively cannulated with 2.7 French microcatheter (Progreat Terumo, Somerset, NJ, USA) with tip of catheter placed and secured distal to the ostia of intercostal / spinal arteries. [8, 24] Repeat angiogram was done from the microcatheter to confirm the position. Road map was used whenever needed while facing any difficulty in superselective cannulation.
Choice of embolising agent and end point determination-
Various embolizing agents have been described in literature like gel foam, PVA particles, n-butyl cyanoacrylates and coils each of them having different merits and demerits. Gel foam being the most temporary occluder but less expensive, easily available and require less operator expertise compared to other agents. N-butyl cyanoacrylates are unique in a way that they do not require thrombogenic properties of blood and can be offered to patients with coagulopathy disorders. They are among permanent distal occluders with increased rates of necrosis and other complications. Use of coils is limited by high costs to patients and requirement of greater expertise in their deployment. There is limited possibility of repeat intervention in effected patients after use of coils. PVA particle are by far considered most suited embolizing agents as they are readily available and relatively inexpensive. The outcomes are comparable to the use of glue as embolising agent.[9, 22] In general, the selection of embolizing agent is governed by operator preference and local availability.
In the present study, we chose PVA particles (Cook Medical, Bloomington, IN, USA) of size 500µm along with gel foam (Upjohn, Kalamazoo, MI, USA) to embolize the responsible circulation. The primary end point was realized when the column of contrast after embolization was seen to stay for atleast five heart beats. Repeat contrast injection was made after a wait of 2-3 min and it was found that in atleast 15 cases (30%) there was a need of more embolising material. This was done till we found the contrast column to stay for five heart beats. The use of glue (Histoacryl, Braun Surgical, SA, Rubi, Spain) was limited to the embolize the arteries in which active extravasation was seen at the time of digital substraction angiography. This was technically the end point in our study. After the primary end point we preferred to inject small amount gel foam slurry as the risk of reflux and non target embolization is higher during this phase.
Results : The outcome of the procedure was categorized into technical and clinical success. Successful catheterization and embolization of the targeted vessel was considered technical success and the stoppage or reduction of hemoptysis to minimal levels was labelled clinical success. We could achieve technical success in all the patients, while early clinical success was reached in 45 (90%) patients. Ten (20%) patients had recurrence, of which none had bleeding episode within 15 days, 5 had episodes within one month and other 5 had recurrence after three months. On retrospective analysis, it was found that all the ten patients with recurrence had cavitatory lung disease, of which 3 had moderate hemoptysis and 7 had severe hemoptysis at the time of presentation. Our experience was in agreement to various other studies who in their respective studies also achieved technical success in range of 95-99%.[7,11] We attribute our increased technical success to preprocedure evaluation with CTA as regular protocol. The clinical success of 80% using PVA particles along with gel foam was relatively less than that has been reported in literature with the use of glue (90-95%) but reduced incidence of major complications (2%) far outweigh the amount of clinical success achieved with the use of latter.[14, 20] The early recurrence rate of 10% in the present study can be attributed to the inability to embolize third or higher order branches due to extensive collateralization. Late recurrences are postulated to occur due to reconstitution of previously embolized arteries or underlying disease progression causing recruitment of new arteries.[10, 15, 21, 25] A comparison between grade of hemoptysis, embolizing agent used, immediate clinical success and overall recurrence is made in Table 1.[9, 13, 15, 21, 26, 27]
Conclusions : Conclusion:
Bronchial artery embolization is a minimally invasive procedure recognized for primary management of hemoptysis of all grades as well as it may also be seen as a bridge to more definitive elective surgical interventions. Preprocedure evaluation with CT angiography can add incremental value by providing vascular roadmap prior to embolization and predicting technical / clinical outcome of procedure. Given that there are high chances of recurrence of hemoptysis in effected patients and need for re-embolization may arise, embolotherapy with PVA particles and gel foam should be preferred over the use of glue and other like permanent occluders.