Press Release Date: 
10/30/2017

Extremes in body mass index (BMI) are associated with higher risk of death and adverse outcome following cardiac surgery for children, adolescents and young adults with congenital heart disease (CHD).

A multicenter research team performed a large retrospective national study of cardiac surgery patients aged 10 to 35 years and recently published their findings in Circulation.

“The risk of extreme BMI on outcomes after operations for congenital heart disease is not well understood,” said the study’s first author, Michael O’Byrne, MD, MSCE, a pediatric cardiologist at Children’s Hospital of Philadelphia (CHOP), who performed the study while at Children’s National Medical Center. “In children and young adults with CHD, very high and very low BMI were both associated with increased risk of adverse outcomes after surgery.  This is a potentially significant issue for the health of our patients.”

The researchers performed a multicenter retrospective cohort study, drawing on the Society of Thoracic Surgeons Congenital Heart Surgery Database. Their analysis covered patients 10 to 35 years old who underwent surgery for CHD between Jan. 1, 2010, and Dec. 31, 2015.

Of 18,337 patients from 18 centers, 16 percent were obese, 15 percent were overweight, 53 percent were normal weight, 7 percent were underweight and 9 percent were severely underweight.
The researchers defined a composite outcome as any major adverse event including death, prolonged length of stay, or a wound complication such as infection. Compared to patients of normal weight, both obese patients and severely underweight patients were 1.3 times more likely to have an adverse outcome.

“Though there is research in adults evaluating the association of BMI and adverse events following surgery, this is the first study to examine this issue in children with CHD.  It is as comprehensive as is possible, including almost all children operated on in the U.S. over the six-year study period,” said O’Byrne.

As the long-term survival of patients with CHD has improved, the distribution of patients with CHD has skewed progressively older, forcing physicians to contend with aspects of patient health beyond CHD, such as body weight and associated diseases.

Obesity is associated with increased lifetime risks of morbidity and mortality, especially as a result of cardiovascular disease. For patients undergoing cardiothoracic surgery, obesity might specifically increase the risk of adverse outcomes in the perioperative period. Obesity frequently occurs in conjunction with type 2 diabetes, hypertension, peripheral vascular disease and pulmonary disease. These comorbid conditions may also interfere with wound healing and recovery from cardiothoracic surgery, as suggested in this current research.

“This is an observational study with some limitations, but it demonstrates an avenue for research that has the potential to benefit our patients. The next steps are studies that evaluate the biological mechanisms underlying these associations, paired with clinical studies evaluating whether targeted interventions for obese and underweight patients can help improve outcomes,” added O’Byrne.

The National Institutes of Health (grant HL130420) supported this study.

Michael L. O’Byrne, et al. "Effect of Obesity and Underweight Status on Perioperative Outcomes of Children, Adolescents, and Young AdultsCirculation, August 22, 2017.

Contact:
Joey McCool Ryan,
Children’s Hospital of Philadelphia,
267-426-6070
mccool@email.chop.edu