Abstract 17967: Systemic Hypertension in Children After Superior Cavo-pulmonary Shunt is Associated With Cerebrovascular Dysautoregulation

Abstract

Introduction: Hypertension is frequently seen after superior cavo-pulmonary shunt. It is unknown if hypertension is necessary to maintain cerebral blood flow due to increased cerebral venous pressure. We sought to determine the range of arterial blood pressures (ABP) associated with intact and impaired autoregulation after superior cavo-pulmonary shunt. Hypothesis: Hypertension (mean ABP>60 mmHg) is associated with cerebrovascular dysautoregulation after superior cavo-pulmonary shunt. Methods: All patients < 12 months undergoing superior cavo-pulmonary shunt from 10/2014 were eligible. Subjects underwent continuous 100 Hz monitoring of ABP, pulmonary arterial pressure (PAP), and near-infrared spectroscopy measurements of cerebral oximetry (rSO 2 ) and cerebral blood volume (CBV). Cerebrovascular autoregulation was measured by the hemoglobin volume index (HVx). ABP and CBV were low-pass filtered as 10 sec average values. Pearson’s correlation coefficient was performed over 300 sec windows. The associations between HVx changes relative to ABP and PAP were tested using linear regression with generalized estimation of equations. Optimal ABP and PAP defined by lowest HVx was determined using a curve-fit algorithm. The relationship between PAP and ABP was tested by piecewise regression. Results: Ten patients were enrolled. Median age and weight were 6.5 months and 6.2 kg. Optimal ABP and PAP were obtained in 7/10. HVx became impaired with increased ABP (top panel) and increased PAP (middle panel), indicating worse cerebrovascular dysautoregulation. PAP increased with increasing ABP (r = 0.55, p<0.0001) with an intercept of 72 mmHg above which ΔPAP/ΔABP doubled from 0.23 [0.22- 0.24] to 0.46 [0.43 - 0.49] (bottom panel). Elevations of ABP above optimal for HVx did not improve rSO2 (p>0.05). Conclusion: Hypertension after superior cavo-pulmonary shunt is associated with elevated PAP, no improvement in rSO 2 , and cerebrovascular dysautoregulation.