Centers experienced in congenital heart surgery appear to boost survival rates by doing a better job of handling postoperative complications, researchers found.
The rate of complications after pediatric heart surgery wasn’t lower at centers with higher volume, Sara K. Pasquali, MD, MHS, of Duke University Medical Center, and colleagues reported in the February issue of Pediatrics.
But when they did occur, the odds of dying were 59% lower when treated at a hospital that handles more than 350 cases per year compared with one seeing fewer than 150 per year (P=0.004).
The survival advantage was particularly pronounced for children undergoing higher risk surgeries.
“Thus, initiatives aimed at improving outcomes may need to focus on not only reducing complications themselves but also improving recognition and management of complications once they occur,” the investigators concluded.
The reason may be that complications are unavoidable in many cases because of patient factors, whereas recognition and treatment of complications once they occur depend more on quality of care, they suggested.
That a volume effect was seen for surgical outcomes came as no surprise, as it has been seen across pediatric surgery types and mirrored findings in adult heart surgery, they noted.
In their analysis of the Society of Thoracic Surgeons’ congenital heart surgery registry database, which over 75% of U.S. centers doing these procedures report to, in-hospital mortality shrank with center experience.
Mortality rates were 4.5% at the lowest volume category of less than 150 cases per year, 3.9% at the intermediate centers, and 3.2% at the highest volume centers doing at least 350 per year.
After adjustment for patient characteristics and surgical case complexity, in-hospital mortality remained 60% higher at centers in the lowest versus highest volume groups (P=0.0004).
Complication rates couldn’t be blamed, as these occurred at a fairly similar 40.9% in the lowest volume and 39.4% in the highest volume hospitals without a significant difference in the adjusted analyses (P=0.69).
But mortality rates among children with a postoperative complication differed more, ranging from 7.6% at the most experienced hospitals to 10.5% at the least experienced.
After adjustment, the risk of dying after developing a complication was:
- 59% elevated at a hospital with fewer than 150 versus more than 350 cases per year (P=0.004)
- 22% higher at a hospital with 150 to 250 cases per year compared with more than 350 (P=0.24)
- 33% higher at a center doing 250 to 350 cases per year versus more than 350 (P=0.09)
The overall trend for complication-related mortality was significant across hospital volumes as a continuous variable (P=0.03).
For children undergoing lower risk (category 1 to 3) cardiac surgery, volume didn’t significantly impact mortality, complications, or survival.
For those having higher risk, category 4 or 5 cardiac surgery, though, survival was 89% better both overall and in those with complications at the highest versus lowest volume centers (P=0.0001 and P=0.003 as continuous variables).
The researchers acknowledged that the database they used doesn’t capture all possible postoperative complications, so coding could have systematically varied across centers.
Other limitations were lack of data on factors such as process measures, training, and staffing as well as the possibility of residual unmeasured confounding.
The analysis was just the first step, Pasquali’s group noted.
“Further research is needed to develop and refine a failure-to-rescue measure in the pediatric heart surgery population and to evaluate factors that may influence this outcome measure,” they wrote.