Coronary artery bypass grafting in Canada: What is its rate of use? Which rate is right?

We reviewed recent reports from administrative databases and clinical registries addressing the utilization of coronary artery bypass grafting (CABG) in Canada. The Canadian CABG rate per 100,000 people increased from 31.1 to 43.2 between 1981-82 and 1986-87. Between 1981 and 1986 the rate in the United States increased from 69.9 to 95.3 per 100,000, consistently about two times the Canadian rate. Provincial data have shown particular growth in utilization among elderly people. However, in the United States the 1985 CABG rate was twice as high as the aggregated age-specific rates for Ontario and Manitoba among people 65 to 74 years of age and four times higher among those 75 years or more. Limited registry data suggest that the Canadian CABG case mix is similar to the case mix in major US centres and that, utilization growth notwithstanding, the procedure is largely applied to patients who should, in theory, benefit (i.e., those with severe angina, impaired left ventricular function and left main-stem or triple-vessel disease). However, chart audits and registry evaluations using explicit criteria are needed to compare the use of CABG in Canada and the United States. In addition, Canadian data show moderate regional and municipal variations, the 1986-87 rates per 100,000 population in major census metropolitan areas varying from 19.5 to 46.9. Areas with consistently low rates raise particular concerns about impaired access to CABG. Reasons for variations should therefore be a research priority.