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Se presenta nuestra experiencia en el tratamiento de la hemoptisis con embolización bronquial en pacientes con bronquiectasias, desde el 2001 al 2008, en el Hospital Italiano de Buenos Aires. Veinte pacientes fueron tratados con este método: 12 mujeres y 8 hombres con una edad media de 51 años (15-83 años). Las causas de bronquiectasias fueron secundarias a infecciones inespecíficas en el 40%; otro 40% secuelas de tuberculosis y 20% por enfermedad fibroquística. La indicación de embolización fue hemoptisis mayor a 300 ml/24 hs o hemoptisis persistentes durante más de 3 días consecutivos con requerimiento de hospitalización. En el 85% de los casos se efectuó embolización bronquial y en el resto (15%) bronquial y mamaria. Este procedimiento fue bilateral en el 60% de los pacientes, 20% solo en el lado derecho y 20% del lado izquierdo. En 18 pacientes se logró oclusión vascular completa de todos los territorios pulmonares patológicos. Control agudo del sangrado fue obtenido en todos los pacientes (100%) y sólo dos presentaron nuevo sangrado a los 8 y 12 meses respectivamente. Como efecto colateral al tratamiento se observó dolor torácico leve y transitorio en dos pacientes. Concluimos que la embolización de las arterias bronquiales constituye un tratamiento adecuado y seguro para el control agudo de la hemoptisis en pacientes con bronquiectasias.

We present our experience on arterial embolization for the treatment of hemoptysis in patients with bronchiectasis between 2001 and 2008 at the Hospital Italiano in Buenos Aires. Twenty patients were treated with this method: 12 women and 8 men with a median age of 51 years (15-83 years). Bronchiectasis was secondary to bacterial infections in 40% and secondary to tuberculosis infection in 40% of the patients; 20% of the patients had cystic fibrosis. Embolization was prescribed when the hemoptysis was above 300 ml/24 hours or the hemoptysis was persistent for more than 3 consecutive days and the patient’s hospitalization was required. In 85% of the cases embolization was done only in bronchial arteries and in the remaining 15% in bronchial and mammary arteries. The procedure was bilateral in 60% of the patients, only on the right side in 20% and only on the left side in 20%. In 18 patients complete occlusion was achieved. Complete control of the bleeding was obtained in 100% of patients. Only two patients had a new bleeding, 8 and 12 months later respectively. The treatment side effects were slight and transitory thoracic pain in two patients. We concluded that the embolization of the bronchial arteries is a suitable and safe treatment to control hemoptysis in patients with bronchiectasis.

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The cytoarchitecture of rat bronchiolar walls was directly visualized from the adventitial side by scanning electron microscopy after removal of collagen and elastic fibers with a KOH-collagenase digestion method. The bronchioles were surrounded by cord-shaped smooth muscle fibers, which ran circularly to the long axis of the bronchiolar tree. Branches of the bronchial artery were located outside the bronchiolar smooth muscle layer, ran toward the periphery, gave off smaller branches one after another, and finally formed capillary networks both inside and outside the smooth muscle layer. Collecting venules arising from the capillary network ran independently of arterioles, but were gradually accompanied with arterioles as they became thickened. Peripheral nerves covered with a perineurial sheath were also present outside the bronchiolar smooth muscle layer; they gave off branches toward the periphery, and finally entered the bronchiolar smooth muscle layer. Lymphatic vessels were sometimes found at the bifurcation of bronchioles. These findings provide important basic data on the structure and functions of the bronchiolar wall.

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We have used vascular castings, light microscopy coupled with tracers, and scanning electron microscopy to define the detailed anatomy of the bronchial arteries in the Wistar rat, a rodent often used in experimental research on lung disorders; namely in those that involve vascular alterations. We found that there are two bronchial arteries in the Wistar rat and that they have a cranial origin, either from the subclavian arteries or from their primary branches. The left bronchial artery was always originated from the internal thoracic artery, ran between the thoracic aorta and the left cranial vena cava and offered branches to the thymus, trachea and esophagus. The right bronchial artery was of variable origin, and was located between the right cranial vena cava and the trachea; it gave off branches to the right cranial vena cava, phrenic nerve, trachea, esophagus and, seldomly, to the mediastinic-pericardial pleura, myocardium and caudal vena cava. In more than half of the rats, there were anastomoses between the bronchial and pulmonary arteries. The histological organization of rat bronchial arteries was different from those of humans, suggesting that there are differences in the resistance to blood flow between the two species. Scanning electron microscopy revealed that the bronchial arteries formed two plexuses surrounding the intrapulmonary airways and also supplied the vasa vasorum of pulmonary arteries and veins. We conclude that there are important differences in the arrangement and structure between bronchial arteries in humans and rats and that this should be taken into account whenever data from experimental studies are to be extended to human (AU)

Hemos usado piezas vasculares, microscopía óptica acoplada con trazadores y microscopía electrónica de barrido para definir la anatomía detallada de las arterias bronquiales en la rata Wistar, un roedor frecuentemente empleado en la investigación experimental sobre disfunciones pulmonares; es decir, en aquellas que implican alteraciones vasculares. Observamos que existen dos arterias bronquiales en la rata Wistar y que son de origen craneal, bien de las arterias subclavias o de sus ramas primarias. La arteria bronquial izquierda siempre se originaba a partir de la arteria torácica interna, recorría una trayectoria entre la aorta torácica y la vena cava craneal izquierda, y mandaba ramas al timo, a la tráquea y al esófago. La arteria bronquial derecha era de origen variable y estaba localizada entre la vena cava craneal derecha y la tráquea; emitía ramas hacia la vena cava craneal derecha, el nervio frénico, la tráquea, el esófago y, aunque raras veces, a la pleura mediastínica-pericardial, el miocardio y la vena cava caudal. En más de la mitad de los animales, se apreciaron anastomosis entre las arterias bronquiales y las pulmonares. La organización histológica de las arterias bronquiales de la rata difería de la de los humanos, sugiriendo que existen diferencias en la resistencia al flujo sanguíneo entre las dos especies. La microscopía electrónica de barrido reveló que las arterias bronquiales forman dos plexos que rodeaban a las vías aéreas intrapulmonares, y también suministraban los vasa vasorum de las arterias y venas pulmonares. Se deduce que existen diferencias importantes en disposición y estructura entre las arterias bronquiales en los humanos y en las ratas y que esto ha de tenerse en cuenta cuando han de extenderse datos procedentes de las ratas a los humanos. (AU)

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BACKGROUND: The bronchial circulation affects both pulmonary vascular and airway activity. Fundamental to understanding the role of the bronchial microcirculation in health and disease is understanding its anatomy. This study sought to identify specific structural elements that might contribute to the drop that occurs between the systemic blood pressure of the bronchial artery and the low pressure of the pulmonary bed into which the bronchial circulation flows and to better describe the connections of the bronchial and pulmonary circulations. METHODS: To do this, the lungs of five sheep were cast by injecting a resin through bronchial and pulmonary arteries. After taking samples for light microscopy, the tissue was digested and the casts were viewed with a scanning electron microscope. RESULTS: Casts of extrapulmonary bronchial arteries were structurally similar to other systemic arteries. Tortuous ones spiraled around bronchi and large blood vessels. Intrapulmonary bronchial arteries, about 100-300 microns in diameter, had sharp branching and deep focal constrictions with great rugosity that completely shut off the flow of the resin. These vessels correspond to the Sperrarterien described by von Hayek (and could cause the resistance associated with the pressure drop). Vasa vasorum ran in the walls of intrapulmonary pulmonary arteries for a variable distance before they entered the lumens of the pulmonary arteries. The smallest blood vessel found that was supplied with vasa vasorum was a bronchial artery 42 microns in diameter. Capillary-like networks with large luminal diameters were found on the pleural surface. CONCLUSIONS: Scanning electron microscopy of microvascular casts provides a fresh description of the bronchial circulation, further delineates the communications of these two circulations, and may structurally account for some pressure drop between the bronchial and pulmonary circulations.

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To determine the importance of the pulmonary or bronchial arteries as the site of injection to cast the lung vasculature rats, we retrospectively compared a group of normal Sprague-Dawley rats that were cast through either the caudal vena cava and right ventricle leading to the pulmonary arteries or through the aorta and bronchial arteries. There was no difference in the appearance of the whole casts or cast-to-lung weight ratios between the two groups, although an incompletely cast lung that was injected through the aorta showed preferential filling of the pleural and peribronchial regions. Nuclear impressions, a sign of good filling, were more frequent and the grade of the images was higher in the group filled through the vena cava. The microvascular density index was not different between the two groups, and a multivariate analysis of variance showed the injection site was not important in determining vascular density. The pulmonary vessels fill nearly as well when injected from the bronchial circulation indicating that the bronchial circulation can immediately perfuse the lung if the pulmonary arteries are obstructed, and casting can be carried out from either side with nearly the same results.

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Lungs from 19 Thoroughbred racehorses with a history of exercise-induced pulmonary haemorrhage (EIPH) were studied using several forms of microscopy. Light microscopy of paraffin sections revealed three lesions in the caudodorsal region of the lungs from each horse. These correspond with the location of blue to brown stains seen at necropsy. These lesions include sequelae of bronchiolitis, hemosiderophages and increased connective tissue. Much of each of the lungs appeared normal, especially the more cranial or ventral portions. Foci of eosinophil infiltration were found in seven of the 19 lungs examined. With two exceptions, these eosinophilic foci had a different distribution to the three lesions. In areas of severe bronchiolar changes and fibrosis, vascular lesions typical of hypertension were found occasionally. Transmission electron microscopy was used to confirm cell types seen by light microscopy and to examine arterioles for changes characteristic of neovascularisation. Areas of enlarged airspaces from the vascular injected right lungs were examined by scanning electron microscopy. The balance of fibrosis and destruction varied in these areas, but none were as extensive as those seen in chronic obstructive pulmonary disease. The authors hypothesise that bronchiolitis and related neovascularisation are essential components of the aetiology of EIPH.

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