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Re-thinking by-pass report card


Hospital report cards are a popular tool for promoting improvements in quality care. In cardiac surgery, they show that Ontario hospitals achieve results that are equal to the best in the world. But reliance on them alone may not provide enough information to achieve the best possible quality of care, says a new Ontario study.

In partnership with Ontario’s Institute for Clinical Evaluative Sciences (ICES), senior cardiac surgeons from all Ontario hospitals performing cardiac surgery reviewed coronary artery bypass deaths (CABG) in 347 randomly selected patients from the hospitals between 1998 and 2003. Ontario has historically had one of the lowest mortality rates for bypass surgery in North America, but Ontario cardiac surgeons wanted to identify if there were additional opportunities for further lowering the relatively low mortality rate (2 percent) after bypass surgery in the province. Ontario’s cardiac surgery report card program has been in place since 1993.

The study examined whether any of the deaths that occurred after bypass surgery in Ontario might have been prevented and whether the estimated rate of preventable death was correlated with the overall bypass mortality rate at each hospital. “The analysis identified a need for better ways to evaluate hospital performance than our current report card models,” says lead author and ICES research fellow Dr. Veena Guru, “report cards are a first step in quality improvement in identifying hospitals that might have failing grades. But we can’t just publish post-operative death rates, if we want to continue to improve the quality of care in Ontario.” In this study experienced cardiac surgeons, a majority of whom are cardiac surgical division heads, reviewed chart summaries for all CABG deaths over the five-year period and identified potentially preventable deaths using a standardized tool. Each death was evaluated by two reviewers and a third assessor was used when the surgeons disagreed. Rates of preventable deaths were then estimated for each hospital and compared to all – cause mortality rates at each centre.

The results:

  • Despite a low-risk adjusted, average mortality range 1.3 to 3.1 percent across Ontario hospitals 111 of 347 (32 percent) deaths might have been prevented as judged by two reviewers (a third reviewer was asked to review in case of disagreement between the first two reviewers).
  • Over the course of the study period there were over 40,000 cardiac surgeries performed in the province of Ontario.
  • Most of the preventable deaths were related to problems occurring during surgery or while patients were recovering in intensive care.
  • Preventable deaths were found across all patient risk categories with the highest rate among those with the lowest preoperative risk.
  • Independent of whether the death may have been preventable, deviations from routine perioperative care were identified by both surgeon reviewers in 32% of assessments, and in 42% by one reviewer.
  • There was no correlation between the preventable death rate at each hospital and the overall bypass mortality rate at each hospital.

“Bypass surgery is one of the common and complex surgeries being performed in Ontario and yet mortality rates for coronary bypass surgery have declined in the province of Ontario to approximately one percent, since the study was conducted,” says Dr. Stephen Fremes, senior author and divisional head of Cardiac Surgery at Sunnybrook Health Sciences, “this and other quality improvement activities may have been responsible for the improvement in outcomes. We are constantly striving to achieve the lowest possible mortality rates possible for our patients.“

“Independent, standardized, expert audits are required to help identify the specific quality problems that exist within and across hospitals, and to guide activities that will lead to meaningful improvements in outcomes. Cardiac surgeons have always been leaders in quality improvement. We hope that surgeons and physicians in other areas of medicine can learn from our experience and conduct their own detailed adverse event audits so that we can have the best possible outcomes for all types of patients in our hospitals,” says Dr. Chris Feindel, co-author on the study and senior cardiac surgeon at the University Health Network in Toronto. The study “Relationship between preventability of death after coronary artery bypass graft surgery and all-cause risk-adjusted mortality rates” is in the June 9 issue of Circulation. The study was funded by the Heart and Stroke Foundation of Ontario.

Author affiliations: ICES (Drs. Guru, Tu, Anderson, Naylor, Austin, Fremes); Divisions of Cardiac and Vascular Surgery (Drs. Guru and Fremes) and General Internal Medicine (Drs. Tu, Etchells, and Naylor) Sunnybrook Health Sciences Centre, University of Toronto; (Dr. Novick) Division of Cardiac Surgery, London Health Sciences Centre; (Dr. Feindel) Division of Cardiovascular Surgery, University Health Network; (Dr. Rubens) Division of Cardiac Surgery, Ottawa Heart Institute; (Dr. Teoh) Division of Cardiac Surgery, Hamilton Health Sciences Centre; (Dr. Mathur) Division of Cardiac Surgery, Sudbury Regional Hospital; (Dr. Hamilton) Division of Cardiac Surgery, Kingston General Hospital; (Dr. Bonneau) Division of Cardiovascular Surgery, St. Michael’s Hospital, University of Toronto; (Dr. Cutrara) Division of Cardiac Surgery, Trillium Health Centre – ONTARIO.

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.


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