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The hemodynamics of coarctation of the aorta have been extensively investigated. These studies have shown that the renal blood flow is within normal limits (1), as in flow to the extremities (2-4), even though the circulation time to the lower parts of the body has a tendency to be prolonged (5). Although coronary blood flow has been reported to be increased (6), the data are quite scattered, and if the two youngest subjects (12 and 15 years old) were excluded, the results would be within normal limits. Left ventricular oxygen consumption was increased in all subjects in the series regardless of age or rate of coronary flow (6). Cardiac output is reported as increased (7) or normal (6) by both the Fick principle and the acetylene method (5). No sizable series has been reported in which cerebral blood flow has been measured, although in two subjects it was reported to be increased (8). Since the cerebral circulation is in the portion of the body where the mean arterial blood pressure is elevated, it appeared worthwhile to study a larger group of subjects to see whether the cerebral vascular resistance adapted itself to this increase in pressure or whether the reported increase in cerebral blood flow (8) was consistent in a larger group. Furthermore , information concerning the relation of the rate of blood perfusion to oxygen consumption is needed for the brain, since it is reported that under certain conditions when coronary blood flow is increased through mechanical means in the isolated or partially isolated preparation, the myo-cardial oxygen consumption is also increased (9-13). Hence under certain conditions that are apparently unrelated to hypoxia, coronary blood flow * may control myocardial oxygen consumption (9-11). Methods Cerebral blood flow was determined by the nitrous oxide saturation method (14) in 20 subjects with coarc-tation of the aorta. The possibility was considered that there might be a significant delay in the passage of blood through the collateral channels about the coarcted segment of the aorta to the femoral artery (5), and, as a result, the femoral arterial nitrous oxide curve might be shifted to the right. If this were true, the femoral arterial versus internal jugular nitrous oxide curves as compared to the brachial arterial versus internal jugular curves would reveal factitial narrowing of the arterio-venous nitrous oxide difference and result in a calculated increase in the cerebral blood flow, as estimated from …

Cerebral Blood Flow in Coarctation of the Aorta