DefinePK

Abstract

Normal pulmonary venous circulation carries oxygenated blood from the alveolar capillaries to the left side of the heart for systemic distribution. Systemicto-pulmonary artery collaterals can develop and may be an important source of blood supply to the lungs.1,2 They usually arise from the aorta or its branches and communicate with the pulmonary arteries at various levels. The diagnosis is made by transthoracic or transesophageal echocardiography, angiography, and more recently by computed tomographic angiography or magnetic resonance angiography.