Initial application in the EACTS and STS Congenital Heart Surgery Databases of an empirically derived methodology of complexity adjustment to evaluate surgical case mix and results.
OBJECTIVE
Outcomes evaluation is enhanced by assignment of operative procedures to appropriate categories based upon relative average risk. Formal risk modelling is challenging when a large number of operation types exist, including relatively rare procedures. Complexity stratification provides an alternative methodology. We report the initial application in the Congenital Heart Surgery Databases of the Society of Thoracic Surgeons (STS) and the European Association for Cardio-thoracic Surgery (EACTS) of an empirically derived system of complexity adjustment to evaluate surgical case mix and results.


METHODS
Complexity stratification is a method of analysis in which the data are divided into relatively homogeneous groups (called strata). A complexity stratification tool named the STS-EACTS Congenital Heart Surgery Mortality Categories (STAT Mortality Categories) was previously developed based on the analysis of 77,294 operations entered in the Congenital Heart Surgery Databases of EACTS (33,360 operations) and STS (43,934 patients). Procedure-specific mortality rate estimates were calculated using a Bayesian model that adjusted for small denominators. Operations were sorted by increasing risk and grouped into five categories (the STAT Mortality Categories) that were designed to minimize within-category variation and maximize between-category variation. We report here the initial application of this methodology in the EACTS Congenital Heart Surgery Database (47,187 operations performed over 4 years: 2006-09) and the STS Congenital Heart Surgery Database (64,307 operations performed over 4 years: 2006-09).


RESULTS
In the STS Congenital Heart Surgery Database, operations classified as STAT Mortality Categories 1-5 were (1): 17332, (2): 20114, (3): 9494, (4): 14525 and (5): 2842. Discharge mortality was (1): 0.54%, (2): 1.6%, (3): 2.4%, (4): 7.5% and (5): 17.8%. In the EACTS Congenital Heart Surgery Database, operations classified as STAT Mortality Categories 1-5 were (1): 19874, (2): 12196, (3): 5614, (4): 8287 and (5): 1216. Discharge mortality was (1): 0.99%, (2): 2.9%, (3): 5.0%, (4): 10.3% and (5): 25.0%.


CONCLUSIONS
The STAT Mortality Categories facilitate analysis of outcomes across the wide spectrum of distinct congenital heart surgery operations including infrequently performed procedures.
Division of Thoracic and Cardiovascular Surgery, The Congenital Heart Institute of Florida, All Children's Hospital, Cardiac Surgical Associates of Florida , University of South Florida College of Medicine, Saint Petersburg and Tampa, FL 33701, USA. jeffjacobs@msn.com
Jeffrey Phillip
JP
Jacobs
Marshall Lewis
ML
Jacobs
Bohdan
B
Maruszewski
Francois G
FG
Lacour-Gayet
Christo I
CI
Tchervenkov
Zdzislaw
Z
Tobota
Giovanni
G
Stellin
Hiromi
H
Kurosawa
Arata
A
Murakami
J William
JW
Gaynor
Sara K
SK
Pasquali
David R
DR
Clarke
Erle H
EH
Austin
Constantine
C
Mavroudis
D001499:Bayes Theorem; D002170:Canada; D006348:Cardiac Surgical Procedures / Q000401:mortality / Q000592:standards* / Q000706:statistics & numerical data; D016208:Databases, Factual; D005060:Europe; D006330:Heart Defects, Congenital / Q000401:mortality / Q000601:surgery*; D017052:Hospital Mortality; D006801:Humans; D015233:Models, Statistical; D017063:Outcome Assessment, Health Care / Q000379:methods*; D020379:Risk Adjustment / Q000379:methods*; D014481:United States