The STS Congenital Heart Surgery Database (CHSD) mortality risk model calculates the operative mortality rate of hospitals performing pediatric and congenital heart surgery, adjusting for procedural and patient-level factors, including:
- Age
- Primary procedure
- Weight (neonates and infants) at time of surgery
- Prior cardiothoracic operation
- Prematurity (neonates and infants)
- Preoperative factors
- Preoperative/Preprocedural mechanical circulatory support (intraaortic balloon pump, ventricular assist device, extracorporeal membrane oxygenation, or cardiopulmonary support)
- Shock, persistent at time of surgery
- Mechanical ventilation to treat cardiorespiratory failure
- Renal failure requiring dialysis and/or Renal dysfunction
- Preoperative neurological deficit
- Any other preoperative factor
- Non-cardiac congenital abnormalities
- Omphalocele
- Gastroschisis
- Congenital diaphragmatic hernia
- Tracheoesophageal fistula
- Anal atresia (imperforate anus)
- Intestinal malrotation
- Hirschsprung disease (congenital aganglionic megacolon)
- Syndrome and chromosomal abnormality risk groups
The mortality risk model incorporates case-mix (risk) adjustment to allow for more meaningful comparison of any given hospital to the aggregate of all hospitals performing pediatric and congenital heart surgery and participating in the CHSD. Adjustment for case mix is especially important because hospitals that tend to treat sicker patients are expected to have higher rates of mortality, which may be due to the condition of these patients or the complexity of the procedures required to treat them—not necessarily because of the care they received. To level the playing field, the CHSD mortality risk model takes into account the variables listed above, all of which can affect surgical results.