Dr. Chang was surprised by the significant difference in mortality rates.
"This is the first study that specifically examined the differences between male and female infants and children undergoing heart surgery. My colleagues and I were quite surprised to find that female children had 51% higher mortality than males. Although we had learned from studies in adults that women tend to have higher mortality, nobody had reported such findings in children," he says.
"This study is the first step towards the understanding of the role of gender in determining outcomes of patients with heart disease, " Dr. Chang adds. "My research team at REI and UCLA has received grant funding from the Agency of Healthcare Quality and Research to further explore possible causes for these gender differences. Understanding the causes for gender differences in mortality will lead to clinical interventions that ultimately can improve the outcome for female infants and children with heart disease."
In the study, investigators identified 6,972 children younger than 21 years of age undergoing 1 of the 23 types of surgical procedures for congenital heart disease. Although the surgeries were performed in 65 hospitals, 30 hospitals had only 1 pediatric cardiac surgery case over the three-year period. After cases in hospitals with less than 10 cases over the study period and cases with incomplete or miscoded data were excluded, 6,593 cases of surgery from 20 hospitals were analyzed. In this group, there were 345 in-hospital deaths, yielding an overall mortality rate of 5.23%.
The study showed that females have a higher incidence of other medical conditions, such as Down syndrome, pulmonary hypertension and failure to thrive. Drs. Chang, Chen and Klitzner speculate that the sex difference in surgical outcomes discovered in this study may be due to biological differences between young males and females that remain to be characterized. The investigators also conclude that the sex difference in outcomes does not appear to be related to factors influencing the delivery of in-hospital medical care.
The American Heart Association (AHA) estimates that in the United States alone, about 25,000 to 30,000, or eight of every 1,000 infants born a year, have a heart defect. There are at least 35 types of recognized defects.
The Research & Education Institute at Harbor-UCLA Medical Center, located on the campus of Harbor-UCLA Medical Center near Torrance, California, is a leading independent, not-for-profit biomedical research institute with an international reputation for scientific discovery, the training of physician-scientists and the provision of community service programs. It is an affiliate of both the David Geffen School of Medicine at UCLA and the Harbor-UCLA Medical Center and has an annual budget of $58 million. The Institute traces its roots back to 1952, when researchers and physicians joined forces with the UCLA School of Medicine on the campus of what was then known as Harbor General Hospital to conduct a handful of research studies. Today, more than 1,000 research projects and clinical trials are being conducted at REI, advancing scientific understanding in order to improve medical outcomes and promote innovation in such areas as autoimmune disorders, cancer, cardiovascular disease, developmental disorders and other pediatric health problems, diabetes, infectious disease, inherited disorders, male contraception, vaccine evaluation and research, and various aspects of women's health.