Bilateral lung transplantation and pulmonary artery reconstruction in a patient with chronic obstructive pulmonary disease and a giant pulmonary artery aneurysm

Abstract

Aneurysms of the pulmonary artery are a rare entity. In a review in 1947, Deterling and Clagett documented only 8 cases in more than 100,000 autopsies. Similarly, there were only 6 cases of pulmonary artery aneurysms in 4000 patients documented from 1785 to 1946. 1 These aneurysms are most commonly found with congenital heart anomalies, but acquired aneurysms may be associated with atherosclerosis, cystic medial necrosis, trauma, infections such as syphilis and endocarditis, or inflammatory processes such as giant cell arteritis. Although many patients with pulmonary artery aneurysms demonstrate pulmonary hypertension, this has not been proven to be a causative factor. In fact, most patients with pulmonary hypertension never have aneurysms. Symptoms are usually vague and may represent manifestations of the primary disease process or may be related to local compression. The disease process leads to rupture and death in approximately 30% of patients, with other deaths resulting from right-sided heart failure or pulmonary embolus. 2 Clinical Summary A 64-year-old man with a history of chronic obstructive pulmonary disease and pulmonary hypertension with giant pulmonary artery aneurysms came to our lung transplant center for evaluation. The pulmonary history was significant for tuberculosis treated at 8 months of age and an open lung biopsy performed in 1965 that showed pulmonary fibrosis. Preoperative pulmonary function tests revealed a forced expiratory volume in 1 second of 0.650 L (20% of predicted) and a diffusing capacity of lung for carbon monoxide of 28.9 (23% of predicted). Lung volumes were consistent with emphysema with a total lung capacity of 139% of predicted and a residual volume of 338% of predicted. Arterial blood gas analysis demonstrated a PaO2 of 53 mm Hg and a PaCO2 of 46 mm Hg on 21% inspired oxygen. The chest radiograph revealed enlarged bilateral pulmonary hila (Figure 1), and a computed tomographic (CT) scan of the chest performed in August 2000 showed a 6.2-cm main pulmonary artery with eccentric thrombus extending to the aneurysmal right and left pulmonary arteries (Figure 2). The lung parenchyma showed evidence of emphysema but no evidence of pulmonary fibrosis. Pretransplant cardiac blood pool imaging revealed decreased right and left ventricular ejection fractions at 29% and 39%, respectively. Cardiac catheterization showed pulmonary hypertension with a pulmonary artery pressure of 58/26 mm Hg, a cardiac index of 2.9 L/min, and no evidence of an intracardiac shunt. The patient was deemed a suitable candidate and was placed on the waiting list for a bilateral lung transplant. When donor lungs became available, he underwent a bilateral lung transplantation with reconstruction of the recipient pulmonary artery using donor aorta. The donor was an otherwise healthy 40-year-old patient who had died in a motor vehicle crash. However, the heart was not harvested because of poor left ventricular function. We were, therefore, able to harvest the entire thoracic aorta along with the lungs. The entire donor thoracic aorta was received with the specimen and was dissected from the lungs and placed in cold heparinized saline solution. The donor lungs were separated while the donor aorta was prepared. The patient was placed in the supine position, and the right and left sides of the chest were exposed through the fourth intercostal space using bilateral anterior thoracotomies and transverse division of the sternum. The lungs were then mobilized, and the aneurysm was seen extending from the origin of the main pulmonary artery into both pulmonary hila. The pericardium was opened, and the patient was placed on cardiopulmonary bypass with bicaval and ascending aortic cannulation. After this, both lungs were excised. When the pulmonary arteries were opened, a large amount of fibrinous clot was seen. The left lung was implanted first. The bronchial anastomosis