Quality Improvement: Surgical Performance

Background

According to the Centers for Disease Control and Prevention (CDC), congenital heart disease (CHD) is the most common type of birth defect, affecting 1% of the population (40,000 births/year). CHD is the leading cause of illness and death associated with birth defects. Fifteen percent of all patients with CHD have associated genetic conditions, and 20% to 30% have physical, developmental, or cognitive problems. In 2004, the health care cost for hospitalization of individuals with CHD was approximately $1.4 billion. It is now feasible to offer surgical correction or palliation to most of these patients. In 2011, 33,733 congenital cardiac procedures were reported to the Society of Thoracic Surgeons (STS). Between 1999 and 2006, CHD was listed as the primary cause of death in 27,960 people. Among these, 48% were infants, often following complex interventions and prolonged ICU stay. Despite recent advances in surgical management, CHD has a significant societal impact in terms of morbidity, mortality, and health care resource utilization. Thus, this patient population presents an enormous challenge to the health care environment where optimal care can greatly influence not only short-term but also long-term physical, intellectual, and psychosocial outcomes.

Outcomes in congenital cardiac surgery are multifactorial and may be affected by (1) preoperative status, such as patient factors (e.g., birth weight, gestational age, complexity of CHD), hemodynamic stability, adequacy of diagnostic evaluation, and appropriateness of the surgical plan; (2) intraoperative factors, such as conduct of anesthesia and cardiopulmonary bypass, surgical technique, and early post-bypass hemodynamic management; and (3) postoperative course, such as serious adverse events and complications. Among these many factors, technical adequacy of repair is likely a significant determinant of successful outcome. Indeed, the degree to which a congenital heart operation achieves its intended result may be the single most important factor determining long-term medical outcomes and costs.

Until recently, hospital mortality, often in the form of cumulative sum (CUSUM) analysis, had been used as a surrogate measure of technical performance in congenital heart surgery. Raw mortality data, however, do not correct for case complexity or other associated factors that can affect outcomes. One alternative, the hospital standardized mortality ratio (HSMR), is intended as an overall measure of in-hospital deaths, a proportion of which are preventable. High ratios may thus suggest potential problems with quality of care. The HSMR is a complex but inexpensive and relatively easy method to calculate, from national or other benchmark data, the patients' predicted risk of death. However, there are a number of methodological challenges in HMSR's construction and interpretation, largely because they are based on administrative databases. Although risk-adjusted in-hospital death rates may be a reasonable measure of institutional performance, this measure is inadequate to assess the performance of individual physicians because many additional factors outside the control of an individual surgeon (e.g., the contribution and impact of other team members) must also be considered. This is especially problematic for high-risk operations, which require a complex multidepartmental microsystem of dedicated teams composed of many individuals and specialties.

The technical performance score (TPS), developed to address the lack of systematic methods for evaluating operative technical adequacy across diagnoses and centers, is a novel tool for assessing technical competency based on widely available clinical and echocardiographic characteristics.

Development of the Technical Performance Score

TPS was developed at Boston Children's Hospital to assess the adequacy of anatomic repair. The technical steps toward an adequate anatomic repair of a lesion are mostly under the control of the surgeon. Intraoperative technical excellence is one of the key factors in determining outcomes, especially in high-acuity operations. A deficit in tools available to measure technical adequacy of a surgical procedure was key to the development of the TPS. This tool was designed to be used for peer and self-assessment and was initially piloted in selected surgical procedures, including repairs of ventricular septal defect, tetralogy of Fallot, complete common atrioventricular canal, arterial switch, and, later, the stage I Norwood procedure. The use was then expanded to include more than 90% of congenital cardiac surgery operations.

The score was created by dividing the surgical procedure into individual subcomponents or subprocedures, based on specific anatomic regions intervened on surgically. TPS is then assessed based on echocardiographic criteria that are designed to capture the individual components of specific operations, as well as unplanned surgical or catheter-based re-interventions prior to discharge in the anatomic areas relevant to the surgical procedure. The components of the score were defined and piloted by a modified consensus process of cardiologists and cardiac surgeons at our center. Based on these prespecified components (subprocedures) that were particular to each operation, each discharge echocardiogram could be classified into one of three categories (class 1 = optimal, class 2 = adequate, or class 3 = inadequate). If all subprocedures have a class 1 optimal score, the overall score for the entire procedure will be class 1 (optimal). If any individual subprocedure is scored as class 1 or 2, the overall TPS for the procedure will be class 2 (adequate). If any subprocedure is scored as class 3 (inadequate), or if the patient undergoes at least one surgical or catheter-based re-intervention in the anatomic area of interest prior to discharge, the TPS will be class 3. Certain specific procedures that result in an unexpected implantation of a permanent pacemaker will also result in the procedure being scored as inadequate (class 3).