Author + information
- Meena Nathan, MD∗ (, )
- Kimberlee Gauvreau, ScD,
- Mihail Samnaliev, PhD,
- Al Ozonoff, PhD,
- Kathy Jenkins, MD, MPH,
- Lisa Bergersen, MD, MPH,
- Jean Connor, PhD, RN, CPNP,
- Frank A. Pigula, MD,
- Steven D. Colan, MD,
- John E. Mayer, MD and
- Pedro J. del Nido, MD
- ↵∗Department of Cardiac Surgery, Children's Hospital Boston and, Harvard Medical School, 300 Longwood Avenue, Bader 273, Boston, Massachusetts 02215
The technical performance score (TPS), which measures technical adequacy of repair in congenital cardiac surgery, has been associated with early outcomes, such as mortality, adverse events, prolonged ventilation and hospital length of stay, and midterm outcomes such as post-discharge mortality, unplanned post-discharge reinterventions, and neurodevelopmental outcomes (1–3). In this study, we hypothesized that improved quality of care measured by TPS would also be associated with lower hospital cost of care.
We prospectively evaluated consecutive unique patients who underwent congenital cardiac surgery at our center between January 1, 2011, and March 31, 2013. Only the first index procedure was included in the analysis; readmissions for any reason, whether planned or unplanned, were excluded. Institutional Review Board approval was obtained for this study.
TPS was calculated as Class 1 (optimal, trivial or no residua), Class 2 (adequate, minor residua), or Class 3 (inadequate, major residua, or pre-discharge reintervention for major residua) based on echocardiographic and clinical findings at discharge. Hospital costs for each admission were calculated using cost-to-charge ratio standardized to 2013 U.S. dollars to account for inflation.
A generalized linear model assuming a gamma distribution with a log link was used to examine the relationship between technical performance score and total hospital costs, adjusting for baseline patient risk using RACHS-1 (Risk Adjustment in Congenital Heart Surgery) and PRECISE (Pediatric Resource Expenditure in Cardiac Specialty Encounters) methods of risk adjustment. Analyses were repeated summing hospital costs for the surgical admission plus all additional costs incurred during the 2 years post-discharge. SAS version 9.4 (SAS Institute, Cary, North Carolina) was utilized for statistical analysis.
There were a total of 1,730 consecutive unique patients meeting inclusion criteria in our cohort. The median total hospital costs for the index operation adjusted to the year 2013 costs across TPS classes as well as adjusted cost increases for hospital admission and 2-year follow-up are shown in Table 1.
After adjusting for baseline patient risk, inadequate TPS remained significantly associated with higher cost (increase by factor of 2.48, p < 0.001) (Table 1). Inclusion of TPS increased R2 from 40.9% to 50.8%, indicating that an additional 10% of the variability in cost was explained by the inclusion of TPS. Results were similar regardless of the method of risk adjustment. Looking at a combination of hospital admission costs and 2-year post-discharge costs adjusted to 2013 dollars, Class 3 TPS was again associated with higher costs (Table 1). R2 increased from 41.5% to 48.4% with inclusion of TPS.
In our study TPS, which measures adequacy of repair, was strongly associated with greater hospital costs even after adjusting for well known risk factors. Inclusion of TPS increased the coefficient of determination for the model from 40.9% to 50.8%, indicating that TPS accounted for an additional 10% of the variability in costs.
Birkemeyer et al. (4) in an elegant study demonstrated that greater technical skill was associated with lower complication, reoperation, and readmission rates following bariatric surgery, confirming that technical adequacy of a repair may be a key factor in outcomes.
Pasquali et al. (5) have shown the existence of significant variability in hospital costs across centers, predominantly related to complications and length of stay. Prior work (1–3) has shown that Class 3 TPS is associated with higher complication rates and greater length of stay and perhaps some of the variability seen in Pasquali et al.’s study could be attributable to the adequacy of repair.
Our study confirms that TPS can serve as an important benchmark for resource use in congenital heart surgery. In our study, the per-patient risk adjusted differences of $8,668 from Class 1 to Class 2, $135,948 from Class 1 to Class 3, and $127,280 from Class 2 to Class 3 suggests substantial potential for cost savings within our institution. This translates into approximately $13.7 million over a year, if all surgery is at optimal level and $10.9 million if quality is improved for all Class 3 to a level of Class 2. With an estimated 35,000 patients undergoing congenital cardiac surgery in the United States each year, our findings imply potential for large aggregate cost savings, but more importantly may result in a significant reduction in complications and length of stay.
Our study has some limitations. The data in this study represents a single institution’s experience. Currently TPS is measured at discharge, and perhaps intraoperative TPS determination and intervention could mitigate costs associated with postoperative interventions. TPS in its current form gives equal weight to all components, and further development is needed to determine which subprocedures carry more weight for any given congenital cardiac procedure. Although common pre-operative factors that may contribute to increased resource use have been included in our analysis, procedure-specific factors may need to be included in future analyses.
Patients with Class 3 TPS have a significantly higher total hospital cost after adjusting for other patient risk factors known to be associated with higher resource utilization. Maximizing technical adequacy of the repair may play a significant role in reducing health care costs. These findings have implications for cost containment and suggest that TPS can be a useful benchmark for resource utilization across centers.
Please note: Dr. Jenkins has received clinical grant support for products manufactured by NuMed and Medtronic through an agreement with Johns Hopkins; and has received a free drug from Novartis for a clinical study; support from Numed, Medtronic, and Novartis is not related to the present work. Dr. Bergersen has served as a consultant for 480 Biomedical Inc. Dr. del Nido owns equity in Nido Surgical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- American College of Cardiology Foundation