Ann Thorac Surg 2004;77:774-775
© 2004 The Society of Thoracic Surgeons
Original articles: cardiovascular
Invited commentary
Richard J. Novick, MD
Division of Cardiac Surgery, LHSC/University of Western Ontario, Rm 4TU35, London Health Science Centre-UC, 339 Windermere Road, PO Box 5339, London, Ontario, Canada, N6A 5A5
e-mail: richard.novick{at}lhsc.on.ca
The purpose of this study was to determine mortality rates in a large cohort of patients awaiting coronary artery bypass grafting (CABG) and to identify, via univariable and multivariable analyses, factors that predict death on the CABG waiting list. This paper represents an update of a December 1996 article by members of the Division of Cardiology of the same institution in Gothenburg, Sweden, which documented a 2.1% waiting list mortality and a 1.7% incidence of nonfatal myocardial infarction in patients waiting for either CABG surgery or percutaneous coronary intervention [1]. Multivariable analyses in that study confirmed that elderly patients, those with a low ejection fraction and diabetics, had a significantly higher incidence of adverse events while waiting.
The current paper by Rexius and colleagues studied only patients awaiting CABG, included over eight times as many subjects, and reported an overall waiting list mortality of 1.3%, with an incidence rate of 5.8 deaths per 100 patient years on the waiting list. Median waiting time for surgery in the entire cohort was 55 days, and only approximately one half of the patients in the "imperative" and urgent groups were operated on within the planned waiting times of two weeks and 12 weeks, respectively. This reality, as well as the fact that the CABG rate in the author's jurisdiction was only 75 per 100,000 citizens, indicated that there was a persistent undercapacity of providing this potentially lifesaving resource during the study period of January 1995 to June 1999. Independent risk factors for death on the waiting list during that interval included male gender, concomitant aortic valve disease, factors increasing operating risk (Cleveland Clinic Risk Score, impaired left ventricular function, and unstable angina), and time after acceptance.
As noted by Rexius and colleagues, there are two different approaches that can be used to reduce adverse events on the CABG waiting list: decrease waiting times for all patients and/or develop a more refined prioritization system to make sure that the patients at highest risk for waiting list mortality proceed to surgery as soon as possible. The Province of Ontario in Canada faced a similar CABG undercapacity issue in the late 1980s, leading to the development of a scoring system for ranking the urgency of the need for revascularization [2]. This initiative led to the formation of a Cardiac Care Network encompassing all of the cardiac surgery centers in the province. Subsequent studies in large cohorts of patients have shown that the median wait times for CABG surgery in Ontario have decreased to less than three weeks; that only 0.4% of patients have died on the waiting list; and that the vast majority of patients were operated on within the maximum recommended waiting time [3, 4]. The latest of these studies confirmed that impaired left ventricular function, advancing age, the presence of concomitant aortic valve disease, and waiting longer than the maximum time recommended by the urgency rating system were independent risk factors for death on the waiting list [4].
Given the success achieved with reducing adverse CABG waiting list events in other jurisdictions, the challenge for Rexius and colleagues is to use their risk model prospectively to improve patient triage for this procedure. If access to life-saving CABG surgery is to be limited due to generalized resource constraints, governments need to support the work of clinical researchers to implement urgency scoring systems, with the expressed goal of minimizing adverse events on the waiting list. Furthermore, since waiting times greater than those recommended by the scoring system have been shown to be significant predictors of death in patients waiting for CABG [4], additional resources need to be allocated by the public and/or private healthcare sectors in countries with undercapacity issues, in order to minimize the likelihood of poor preoperative outcomes.
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- Bengtson A., Karlsson T., Hjalmarson A., Herlitz J. Complications prior to revascularization among patients waiting for coronary artery bypass grafting and percutaneous transluminal coronary angioplasty. Eur Heart J 1996;17:1846-1851.[Abstract/Free Full Text]
- Naylor C.D., Baigrie R.S., Goldman B.S., Basinski A. Assessment of priority for coronary revascularization procedures. Lancet 1990;335:1070-1073.[Medline]
- Naylor C.D., Sykora K., Jaglal S.B., Jefferson S., Steering Committee of the Adult Cardiac Care Network of Ontario. Waiting for coronary artery bypass surgery: population-based study of 8,517 consecutive patients in Ontario, Canada. Lancet 1995;346:1605-1609.[Medline]
- Morgan C.D., Sykora K., Naylor C.D., Steering Committee of the Cardiac Care Network of Ontario. Analysis of deaths while waiting for cardiac surgery among 29,293 consecutive patients on Ontario, Canada. Heart 1998;79:345-349.[Abstract/Free Full Text]
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