ABC | Volume 113, Nº5, November 2019

Case Report Calik et al. LIMA to pulmonary artery fistula Arq Bras Cardiol. 2019; 113(5):1002-1005 Figure 1 – The angiographic view of the fistula formation between LIMA and pulmonary artery. Burchell and Clagett 1 in 1947. Since then, such cases have been published very rarely. LIMA to PA fistulas can be congenital or acquired. The common cause of acquired form is CABG but it may also be secondary to trauma, infection, and neoplasm. 2-4 Madu et al. 5 reported the incidence of LIMA to PA fistula as 0.67% by means of reviewing 595 post-CABG angiograms and the meantime for development of such a fistula was about 5 years. A similar study, conducted by Guler et al. 6 reviewed 537 post-CABG patients’ coronary angiogram and reported only 5 (0.93%) of themwere having fistula formation originating from LIMA and draining to Pulmonary vasculature. Several pathophysiologic mechanisms have been proposed for LIMA to PA fistula formation although the underlying cause is not fully understood. However, predisposing factors for the development of fistula include; the use of electro-cautery instead of ligation of the side branches while harvesting the LIMA, 7,8 injury to the pleura and lung parenchyma 9 that may cause direct contact between LIMA and pulmonary vasculature, operative site infection and inflammatory process leading to neovascularization. The most common reported symptom is persistent angina despite optimal medical therapy. Coronary steal phenomenon and myocardial ischemia due to substantial shunting of blood from the LIMA to the PA is proposed as the underlying pathophysiological mechanismof angina. 5 Nonetheless, patients may consult physicians with also dyspnea and other congestive Figure 2 – The angiographic view after first three coils which couldn’t completely occlude the fistula. 1003