[Unstable angina due to communication between the coronary artery and the right pulmonary artery in patient with Takayasu's arteritis].

A sixty three year old woman suffering from Takayasu's arteritis with involvement of the aortic arch, subclavia arteries and occlusion of the right pulmonary artery, developed progressive precordial pain. Exercise electrocardiogram disclosed ST segment depression. Coronary arteriograms demonstrated no coronary stenosis, but collateral circulation arising from circumflex coronary artery to right pulmonary artery. The collateral blood flow was considered to be of great importance, and causing the coronary steal syndrome, leading to angina pectoris.