A decade's experience with quality improvement in cardiac surgery using the Veterans Affairs and Society of Thoracic Surgeons national databases

Abstract

Objective: To review the Department of Veteran Affairs (VA) and the Society of Thoracic Surgeons (STS) national databases over the past 10 years to evaluate their relative similarities and differences, to appraise their use as quality improvement tools, and to assess their potential to facilitate improvements in quality of cardiac surgical care.

Summary background data: The VA developed a mandatory risk-adjusted database in 1987 to monitor outcomes of cardiac surgery at all VA medical centers. In 1989 the STS developed a voluntary risk-adjusted database to help members assess quality and outcomes in their individual programs and to facilitate improvements in quality of care.

Methods: A short data form on every veteran operated on at each VA medical center is completed and transmitted electronically for analysis of unadjusted and risk-adjusted death and complications, as well as length of stay. Masked, confidential semiannual reports are then distributed to each program's clinical team and the associated administrator. These reports are also reviewed by a national quality oversight committee. Thus, VA data are used both locally for quality improvement and at the national level with quality surveillance. The STS dataset (217 core fields and 255 extended fields) is transmitted for each patient semiannually to the Duke Clinical Research Institute (DCRI) for warehousing, analysis, and distribution. Site-specific reports are produced with regional and national aggregate comparisons for unadjusted and adjusted surgical deaths and complications, as well as length of stay for coronary artery bypass grafting (CABG), valvular procedures, and valvular/CABG procedures. Both databases use the logistic regression modeling approach. Data for key processes of care are also captured in both databases. Research projects are frequently carried out using each database.

Results: More than 74,000 and 1.6 million cardiac surgical patients have been entered into the VA and STS databases, respectively. Risk factors that predict surgical death for CABG are very similar in the two databases, as are the odds ratios for most of the risk factors. One major difference is that the VA is 99% male, the STS 71% male. Both databases have shown a significant reduction in the risk-adjusted surgical death rate during the past decade despite the fact that patients have presented with an increased risk factor profile. The ratio of observed to expected deaths decreased from 1.05 to 0.9 for the VA and from 1.5 to 0.9 for the STS.

Conclusion: It appears that the routine feedback of risk-adjusted data on local performance provided by these programs heightens awareness and leads to self-examination and self-assessment, which in turn improves quality and outcomes. This general quality improvement template should be considered for application in other settings beyond cardiac surgery.

Figure 1. The unadjusted surgical death rate for coronary bypass surgery (CAB) in the Society of Thoracic Surgeons (STS) National Database has decreased from 3.8% to 2.7% during the past 10 years.

Figure 2. This graph shows the significant reduction in the observed to expected ratio for surgical death in patients undergoing coronary artery bypass grafting (CABG) procedures from 1990 to 1999: the ratio decreased from 1.5 to 0.9.

Figure 3. This figure, typical of the graphics transmitted back to the primary surgeons, shows the local observed to expected ratio for surgical death for coronary artery bypass (CAB) procedures, with side-to-side comparisons to the region and nation for benchmarking purposes. STS, Society of Thoracic Surgeons database.

Figure 4. The unadjusted surgical death rate for coronary bypass only (CAB) procedures in the national Veterans Affairs (VA) system decreased from 4.3% in 1989 to 2.7% in 2000, as shown in this graph.

Figure 5. A marked reduction in the observed to expected ratio (O/E) for surgical death for coronary bypass graft (CABG) procedures in the national Veterans Affairs system is shown here with 10-year and 3-year trends. The reduction has been particularly significant in the past 3 years.

Figure 6. This graph is an example of the data transmitted back to the local hospitals for comparison of their performance compared with the other 41 hospitals in the Veterans Affairs system. The data are blinded as to hospital identification except for one’s own center. O/E ratio, observed to expected ratio; CABG, coronary artery bypass grafting.

Figure 7. Recently the effect of off-pump coronary artery bypass on risk-adjusted surgical death (MORT) and complication (MORB) rates was examined in both the Veterans Affairs (VA) and the Society of Thoracic Surgeons (STS) databases; this graph shows a significant reduction in both rates for off-pump procedures compared to on-pump group, with an odds ratio of 1 for the control group.