Outcomes of hypoplastic left heart syndrome: analysis of National Inpatient Sample Database 1998-2004 versus 2005-2014.

Neonates with hypoplastic left heart syndrome (HLHS) were identified from the National Inpatient Sample dataset for the years 1998-2014. These patients were stratified into two chronological groups, past group (1998-2005) and recent group (2006-2014). A total of 20,649 neonates with HLHS were identified. Of them, 9179 (44.5%) were born in the past group and 11,470 (55.5%) in the recent group. Median birth weight was significantly less in the recent group (2967 g vs. 3110 g, p = 0.005). The patients in the recent group had more patients with low birth weight ( < 2.5 kg) and prematurity (8.7% vs 7.6% and 12.7% vs. 4.3%., respectively). In addition, recent group had more comorbidities including chromosomal anomalies, total anomalous pulmonary venous return, and kidney anomalies (5.6% vs. 3.6%, 2.3% vs. 1.7%, and 5.6% vs. 3.6%, respectively, p < 0.001); these were associated with a higher rate of extracorporeal membrane oxygenation utilization (9.2% vs. 4.5%, p < 0.001). Consequently, median length of stay was longer in the recent group (8 vs. 6 days, p < 0.001).Conclusion: Despite the higher frequency of comorbidities in recent group, the mortality rates decreased by 20% (from 25.3% to 20.6%, p < 0.001). Balloon atrial septostomy was performed less frequently in the recent group (23.3% vs. 16.1%, p < 0.001).What is known:• Hypoplastic left heart syndrome has the highest mortality among congenital cardiac defects during the first year of life.• Limited studies on patients' comorbidities and mortality rates trends over last two decades.What is new:• The study utilized a national database to compare in-hospital mortality and length of stay between the two time periods 1998-2005 and 2006-2014.• The recent group had more comorbidities (prematurity, chromosomal anomalies, total anomalous pulmonary venous return, and kidney anomalies), and there was higher rate of ECMO and longer length of stay, while mortality rates decreased by 20%.