Seeking Better Outcomes in Coronary Artery Bypass Grafting: Lessons From Past Experience
A re we delivering the safest and most effective care? How best can we learn from our experience? For healthcare professionals who ask these questions, the article by Guru and colleagues in this issue of Circulation is essential reading. 1 These Canadian investigators performed an implicit review and retrospective analysis of 347 randomly selected inhospital deaths after coronary artery bypass grafting (CABG) surgery and determined that approximately one third might have been prevented by
... prevented by better care. The study offers many important lessons with implications far beyond cardiac surgery. Article p 2969 Guru and colleagues uncovered many opportunities for important improvements in a hospital system that could have been content with its successes. Their investigation was conducted in a system with no low-volume hospitals and low risk-adjusted mortality rates and involved the participation of experienced staff surgeons and division chiefs. They found remarkably high percentages of preventable deaths, defined as deaths that could have been avoided had optimal care been delivered. Optimal care was considered to be the best possible care that could be delivered if current resources were operating at peak performance in accordance with the best available evidence at the time of the hospital admission. The investigators found that as many as 107 preventable CABG-related deaths occurred in Ontario in fiscal year 2000 to 2001. These deaths occurred in every institution. In particular, the highest percentages of preventable deaths were not clustered at the institutions with the highest risk-adjusted mortality rates, indicating that even a low mortality rate should not beget complacency. Even in the hospital with the lowest risk-adjusted mortality rate, about 20% of deaths were deemed to be preventable. Guru and colleagues focused specifically on contributing causes of deaths that may have been prevented. In this way, many deaths had more than 1 potential contributing cause. In each case, the reviewers identified a clinical situation in which death may have been averted had better care been delivered. Interestingly, preventable deaths occurred frequently across the spectrum of patient risk and were actually more common among patients with lower preoperative risk. The Guru study is not without precedent. In a retrospective chart review of 15 000 randomly selected admissions in Colorado and Utah during 1992, Gawande and colleagues sought to identify surgical adverse events and classify them as to whether they were preventable. 2 Among the surgical adverse events, 54% were deemed preventable. For those adverse events associated with CABG surgery, 38% were labeled as preventable, a percentage that is similar to the preventable death rate in the present study. The phenomenon of preventable deaths is not unique to cardiac surgery but is likely present for many high-risk medical and surgical conditions at hospitals throughout the world. We have a growing proficiency in measuring and highlighting problems in our healthcare system, yet our current measures have limits. The quantitative measures, such as those in the public profiling effort by the Centers for Medicare & Medicaid Services, illuminate more information about hospital performance, 3 but we need increasingly sophisticated approaches to diagnosing the underlying causes of suboptimal performance. Looking at outcomes provides a more comprehensive view of performance than does the narrow assessment of specific processes, but it does not indicate where improvement can occur. 4 Thus, our movement toward explicit, quantitative measures of quality has improved the reliability of our assessments and revealed opportunities for improvement that were once invisible, but it has fallen short in providing insights about how to improve. Although outcomes measures are intended to stimulate efforts to improve, they are also designed for accountability. The national publicly reported outcomes measures can only give hospitals a sense of where they stand compared with others and how they perform compared with historical standards; guiding actions within institutions requires more nuanced information from the experience of the institution and the experience of others. This insight may only be achieved through implicit review of patient records and thoughtful investigation of the details of patient care. The methods of Guru and colleagues provide an example of how this approach can best be achieved among a consortium of institutions intent on finding out how relatively low bypass mortality rates might be made even lower.