[Immunomorphological study of angiotensin-converting enzyme in coronary shunts].

Coronary bypass surgery is the operation of choice in patients with coronary atherosclerosis. However, some time later, venous shunts frequently stop functioning after successful surgery. The reasons for this include intimal hyperplasia occurring in response to release of cytokines, angiotensin II in particular. In man, the latter is formed by angiotensin-converting enzyme or chimase. The findings show that elevated ATF concentrations are found in some cells in the area of intimal hyperplasia, in macrophages and smooth muscle cells of the shunt hyperplastic intima. The increased ATF concentration in the aorto-coronary shunt cells results in the elevated levels of angiotensin II, the migration of smooth muscle cells, their hypertrophy and hyperplasia, the formation of atherosclerotic plaques, thrombosis, and circulatory disorders.