Publicly reported outcomes for Congenital Heart Programs. What are the key attributes of high performing programs?

Publicly reported data for Congenital Heart Centers (January 2019 – December 2022) was released on the STS website last week. Data from the website was extracted to make a plot of each center’s Observed to Expected (O/E) risk-adjusted mortality against annualized surgical volume. The red dots denote the top 10 pediatric heart centers according to USNWR in 2023. High-performing mid-sized and small-volume programs are denoted by a dotted line box which denotes the centers with O/E ratios in the lowest quartile compared to all other centers (e.g. high performers).

Interestingly, the largest centers tend to have O/E ratios of ~1.0 which indicates that they are performing as expected by the STS risk adjustment model. These are widely regarded as excellent centers and the proximity to 1.0 may be related to the inherent difficulty in keeping a large organization focused with a well-aligned mission among the many participating teams, trust between teams, a sufficient common pool of shared knowledge, consistent management patterns with empowered execution, and the ability to overcome the communication challenges associated with very large organizations. A common problem when many large teams work together is the loss of ‘one-ness’ (McChrystal, Team of Teams).

The high performing mid-sized programs may be working in a sweet spot where the size of the patient population can be managed by a relatively small group of highly connected clinicians (lateral connectivity). Many of these centers consistently outperform the large programs and the current data suggests that bigger may not always be better.  The data suggesting that mid-sized programs may be the optimal size is consistent with a study by Karl Welke et al which indicates that there may be lower risk adjusted mortality in the 200-400 case/year range (Welke, Ann Thor Surg, in press)

The high performing small-volume programs are an interesting group of centers. The attributes of these small programs that promote excellent performance are not known and have rarely (if ever) been studied. Identification of the important attributes could enable other small-volume programs to import these concepts into their programs – and hopefully improve the delivery of care in all programs. Clearly ‘small’ is not a four-letter word. We need to learn more about small-volume centers that do well.

Overall, we need to study programs of any size that perform well to identify the important attributes that make it possible to achieve excellence in comparison to comparably sized peers. My personal bet is that the set of important attributes differs in the setting of small-volume, mid-sized, and large programs. I believe that a few individual caregivers can successfully drive small-volume programs, a tightly organized central team with administrative support is critical in mid-sized programs, and the organization-wide system of care is the most important determinant of outcomes in the large programs. This is an active area of research by the CHSS Quality and Outcomes Committee.