Previous reports have linked Norwood patients to neurodevelopment impairment. Now, a study published online March 28 in Circulation has shown that neurodevelopment impairment in these patients may be associated with innate patient factors and morbidity in the first year rather than intraoperative management strategies.
“Survival to adulthood is becoming a reality for patients with hypoplastic left heart syndrome (HLHS) and other single right ventricle (RV) anomalies treated with staged repair from the Norwood operation to the Fontan procedure,” wrote Jane W. Newburger, MD, MPH, of Children’s Hospital Boston and Harvard Medical School, and colleagues. “This remarkable progress has exposed a high prevalence of neurodevelopmental impairment in survivors, affecting their educational achievement, employability and quality of life.”
During the Single Ventricle Reconstruction (SVR) trial, a large prospective study, Newburger and colleagues compared outcomes with a modified Blalock-Taussig shunt with right-ventricle-to-pulmonary-artery shunts and assessed 14-month neurodevelopment outcomes in 373 transplant-free Norwood survivors.
The mean age of these patients at follow-up was 14.3 months and the mean time between Norwood and Stage II procedures was 5.2 months.
In the 296 patients whose parent history was available, 47 percent received development support within their first year of life. Of this cohort, 39 percent received physical therapy, 26 percent received speech therapy, 10 percent received early intervention and 4 percent had other forms of support.
The researchers reported genetic syndromes and other anomalies in 25 percent. These patients were subject to longer hospitalizations (28 days vs. 22 days) and lower birth weights, the authors noted.
Patients with no genetic syndrome had the highest levels of psychomotor development index (PDI) and major depression inventory (MDI) scores and shorter hospital length of stay. The researchers found location of clinical centers, birth weight, longer length of stay and complications between the time of the Norwood procedure and discharge were independent factors of a lower PDI score.
“We found no significant relationship of PDI or MDI score to perfusion type, other aspects of vital organ support (e.g. hematocrit, pH strategy), or cardiac anatomy,” the authors wrote.
“We found a high prevalence of neurodevelopmental impairment in patients with HLHS syndrome and other single right ventricle anomalies, discouragingly similar to that described in patients who underwent Norwood surgery from 1998 to 2003.”
Patient factors including genetic syndrome, lower maternal education and low birth weights were factors the led to enhanced risk. While the majority of these factors are not modifiable, postponing the time of elective delivery may improve birth weight.
“Patients with HLHS have a high rate of cerebral dysgenesis and microcephaly, suggesting that genetic factors and epigenetic insults contribute to abnormalities in brain development,” the authors wrote. “Furthermore, abnormal fetal cerebral hemodynamics could adversely affect brain development.”
Interventions such as postponing delivery time, protecting the brain during the period of hemodynamic instability and enhancing development support post-Norwood discharge, could help improve neurodevelopmental outcomes in these patients, the authors summed.