Background: Congenital Heart Disease (CHD) is one of the leading birth defects in the United States, encompassing approximately 40,000 neonates (newborns) annually (American Heart Association, 2015; Reller, Strickland, Riehle-Colarusso, Mahle, & Correa, 2008). Advances in surgical technique and postoperative management result in approximately 1.3 million adults who are CHD survivors (American Heart Association, 2016). Despite efforts aimed at prevention and early detection of developmental delays in infants and children, many with CHD will have neurologic deficits lasting into adulthood, influencing employability, self-care, and quality of life (Pike et al., 2007; von Rhein et al., 2014). Large multicenter studies have ruled out surgical factors as independent predictors for these developmental delays leading to examination of factors more intrinsic to the neonate as the cause for poor outcomes (Gaynor et al., 2015; Newburger et al., 2012). A hypothesis not extensively examined is whether impaired Cerebrovascular Autoregulation (CA), is responsible for poorer neurodevelopmental outcomes in preoperative neonates with CHD (Paulson, Strandgaard, & Edvinsson, 1990).
Purpose: The purpose of this study was to assess CA in neonates with and without CHD, and to evaluate the association of CA with neurodevelopmental outcomes. The specific aims of this study were to: 1) Compare CA between 28 preoperative neonates with CHD and 16 age- and gender-matched healthy neonates at less than 12 days of age; 2) Examine associations between impaired CA and abnormalities in motor, auditory, and visual functions when controlling for preoperative neonates with and without CHD; and 3) Exploratory Aim: Determine associations of clinical factors such as: a) 1 minute Apgar scores, b) cord pH, c) head circumference, and d) birth weight to impaired CA.
Methods: This study was a prospective, cross- sectional, 2-group case control design. We enrolled 44 neonates (28 with CHD and 16 healthy controls). Inclusion/exclusion criteria were chosen to decrease variability in CA. CA was determined using regional cerebral oxygenation (rSO2) with the INVOS Somanetics Near Infrared Spectroscopy (NIRS) 5100C (Troy, MI) device and a postural change. The Einstein Neonatal Neurobehavioral Assessment Scale (ENNAS) measured neurodevelopmental outcomes.
Results: The Χ2 test revealed no significant difference in impaired CA between CHD and control groups (p =.38). Multiple linear regressions showed CHD neonates significantly associated with poorer total neurodevelopmental scores (β =9.30, p =.02) and motor scores (β = 7.6, p = .04) when controlling for CA status. Independent t-tests demonstrated baseline and sitting rSO2 were significantly lower in the CHD neonates (p <.00).
Discussion: The results provide evidence of poorer developmental outcomes and hypoxemia in preoperative CHD neonates warranting further investigation of causes for delays. For patients who might be at risk for impaired CA, some strategies to optimize cerebral blood flow are: 1) maintaining higher systolic blood pressures; 2) preventing episodes of hypoxemia and; 3) taking more time to change the patient’s positions. Identifying the mechanism of injury and the neonates at higher risk of developing delays will assist healthcare providers in tailoring interventions to prevent neurodevelopmental delays in this vulnerable population.