The coronary circulation in cyanotic congenital heart disease.

Background: Dilated coronary arteries, coronary blood flow, and the paucity of coronary atherosclerosis have not been studied in cyanotic congenital heart disease.

Methods: Coronary arteriograms were interpreted in 59 cyanotic adults, and dilated coronaries were examined histologically in 6. Coronary blood flow was determined with N-13 ammonia positron emission tomography in 14 Eisenmenger syndrome patients and in 10 controls. Total non-fasting cholesterols were retrieved in 279 patients who were divided into: Group A--143 cyanotic unoperated, Group B--47 acyanotic after operation, Group C--41 acyanotic unoperated, Group D--48 acyanotic before and after operation. Total cholesterol was <160 mg/ml in 58% of Group A and 51% of Group B. Low- (LDL) and high-density cholesterol (HDL) and triglycerides were determined in 57/82 hypocholesterolemic patients. Platelet counts were determined in 105 patients. Platelet production, megakaryocyte production, platelet destruction, and platelet activation were studied.

Results: Angiography--88% of extramural coronary arteries were mildly or moderately dilated to ectatic and tortuous. Loss of medial smooth muscle, increased medial collagen, and duplication of internal elastic lamina were identified histologically. Basal coronary flow was increased, but hyperemic flow following IV dipyridamole was comparable in patients and controls. Atherosclerosis was not detected in either the arteriograms or the necropsy specimens. Thrombocytopenic resulted from reduced platelet production.

Conclusions: Coronary arteries in cyanotic congenital heart disease dilate in response to endothelial vasodilators coupled with mural attenuation caused by medial abnormalities. Basal flow was increased, but flow reserve was normal. Coronary arteries were atheroma-free.