HOUSTON (FRONTLINE MEDICAL NEWS) – Among neonates and infants who underwent shunt construction as a source of pulmonary blood flow, early, in-hospital shunt failure occurred in 7.3% of cases, results from a large retrospective study showed.

“Approximately one in seven patients who experiences cardiac surgery in the first year of life undergoes construction of a systemic to pulmonary artery shunt of some type,” one of the study investigators, Marshall L. Jacobs, MD, said in an interview. The study was presented at the annual meeting of the Society of Thoracic Surgeons.

“Early failure of such shunts is an incompletely understood phenomenon which accounts for important morbidity and mortality among infants and neonates. Much of what is known about shunt failure is based on experiences reported from individual institutions. The few multicenter studies to date have been clinical trials that focused primarily on pharmacologic strategies intended to reduce the risk of shunt failure due to thrombosis. Their utility for guiding clinical decision making has been limited. Some have been underpowered; some have had limited risk adjustment of subjects.”

The current investigation, which began when Nhue Do, MD, was a cardiac surgery chief resident at Johns Hopkins Hospital, Baltimore, is the largest reported analysis of factors associated with postoperative in-hospital shunt failure in neonates and infants with congenital heart disease. It is the first multicenter study to define preoperative risk factors and patient characteristics associated with early shunt failure.

Dr. Do, who presented the findings at the meeting and is currently a Congenital Heart Surgery Fellow at the Children’s Hospital of Philadelphia, and a team of 11 other investigators utilized the STS Congenital Heart Surgery Database to identify 9,172 neonates and infants who underwent shunt construction as a source of pulmonary blood flow at 118 institutions from 2010 to 2015. Criteria for shunt failure included a documented diagnosis of in-hospital shunt failure, shunt revision, or catheter-based shunt intervention. The investigators used multivariable logistic regression to evaluate risk factors for in-hospital shunt failure.

Of the 9,172 at-risk neonates and infants, 674 (7.3%) experienced early, in-hospital shunt failure. “The observed rate of early shunt failure varied across the many specific types of shunts, and was lower with systemic ventricle to pulmonary artery shunts (as in the Sano modification of the Norwood procedure) than with the systemic artery to pulmonary artery shunts,” said Dr. Jacobs, who is a cardiothoracic surgeon at Johns Hopkins University, Baltimore.

In multivariable analysis, risk factors for in-hospital shunt failure included lower weight at operation for both neonates and infants, preoperative hypercoagulable state, and the collective presence of any other STS Congenital Heart Surgery Database preoperative risk factors. Neither cardiopulmonary bypass nor single ventricle diagnosis were risk factors for shunt failure. The investigators also observed that patients with in-hospital shunt failure had significantly higher rates of operative mortality (31.9% vs. 11.1%) and major morbidity (84.4% vs. 29.4%), and longer postoperative length of stay among survivors (a median of 45 vs. 22 days).

“Understanding the characteristics of the patient groups found to be at highest risk for early shunt failure is helpful in identifying individual patients that may warrant expectant surveillance, enhanced pharmacologic management, or other strategies to reduce the risk of shunt failure,” Dr. Jacobs concluded.

“But perhaps more importantly it provides key information that may be helpful in the design and development of future clinical trials and/or collaborative quality improvement initiatives designed to reduce the cost in lives and resources that is associated with early shunt dysfunction.”

He acknowledged certain limitations of the study, including its retrospective observational design and the voluntary nature of the STS Congenital Heart Surgery Database. “In addition, some potentially important variables, such as detailed data concerning preoperative test results of coagulation assays are not collected in the STS Congenital Heart Surgery Database,” he said.

The research was supported by the STS Access & Publications Research program. The investigators reported having no financial disclosures.