Abstract 19360: Abnormal Cerebral Circulation in Patients With Fontan Circulation
Background: Impairment of higher brain function often occurs in patients who have undergone Fontan surgery. Apart from the surgery being conducted immediately after birth, abnormalities of the cerebral circulation induced by reduced systemic blood flow and higher central venous pressure in the Fontan circulation may be responsible for this. We tested our hypothesis that patients with Fontal circulation have abnormal cerebral circulation.
Methods: The subjects were 43 patients who had undergone Fontan surgery (Fontan group) and, as a control group, 24 patients who had undergone surgery for tetralogy of Fallot (TOF group). The blood flows in the common carotid artery, superior vena cava (SVC) and inferior vena cava (IVC), as well as the cardiac index (CI), were measured on MRI scan. Oxygen consumption and the oxygenation balance index (OBI), reflecting the ratio between oxygen supply and demand of the upper and lower halves of the body, were calculated from the cardiac catheterization data.
Results: The blood flows in the common carotid artery and SVC correlated positively with CI in both groups (Fontan group: r = 0.89, 0.93, P < 0.00001; TOF group: r = 0.95, 0.78, P < 0.001, respectively), suggesting that low cardiac output directly affects cerebral circulation. The relationship between CI and blood flow ratio between SVC and IVC (SVC/IVC flow ratio) remained stable regardless of CI in the TOF group, but in the Fontan group, CI correlated positively with SVC/IVC flow ratio. It was therefore suggested that, in the Fontan group, cerebral blood flow is difficult to maintain when cardiac output is low. The OBI was maintained around 1 (1.1 ± 0.4) in the Fontan group, but the cases with OBI < 1 had decreased blood flows in both the common carotid artery and the SVC. In the Fontan patients, when blood flow was reduced in the upper half of the body, increases in oxygen extraction represented by ▹SatO2 = (SatO2aAo-SatO2SVC) were not sufficient to maintain cerebral oxygen consumption.
Conclusion: In the Fontan group, although cerebral oxygen consumption tends to be reduced when the blood flow distribution to the brain is decreased, compensation is not adequate. This suggests difficulty in maintaining the balance between cerebral oxygen supply and demand in Fontan circulation.
Author Disclosures: C. Kurishima: None. S. Kuwata: None. Y. Iwamoto: None. H. Saiki: None. H. Ishido: None. S. Masutani: None. H. Senzaki: None.
- © 2016 by American Heart Association, Inc.