Effects of exercise on coronary collateralization--angiographic studies of six patients in a supervised exercise program.

The existence of coronary collaterals in man and a positive correlation of their extent with the degree of coronary artery obstruction has been shown. The theory that functional collateralization associated with coronary occlusive disease is a response to local hypoxia is widely advocated. It was theorized here that coronary heart disease patients might enhance coronary collateralization through exercise-induced myocardial hypoxia. This pilot study was carried out to test the specificity of coronary arteriography for measuring changes in collateralization after a period of exercise training. Reports of follow-up examinations 7 years after program termination are also included. Six volunteer, male subjects--3 months to 3 years post-myocardial infarction--completed 10-12 months of medically-supervised exercise. All had an intensive cardiovascular work-up, serial treadmill exercise tests and coronary arteriography before and after training. All demonstrated the expected physical, physiological, metabolic, and psychological benefits. Two showed some definite, increased collateralization, however, in both of these the changes may have been a response to some extension of the occlusive disease and not exclusively an exercise effect. It was evident that minute changes in coronary collaterals are detectable by selective coronary arteriography, but that the specific effect of exercise on the development of collaterals could only be determined by a large-scale, controlled program with randomization of the multiple, uncontrollable variables among exercise and non-exercise populations.