Monitoring the diffusion of a technology: coronary artery bypass surgery in Ontario.

Technology assessment involves not only examining technologies before they are released but also their diffusion into practice once they have been released. In this study we show how basic analysis of a large administrative data set, combined with a review of evidence on effectiveness, can be used as the first step in technology assessment. We analyze the use of coronary artery bypass surgery (CABS) in the province of Ontario, Canada. The annual number of procedures increased 52 per cent over a seven-year period between 1979 and 1985. Large increases in CABS rates in the over-65 population accounted for more than half of this increase in procedures. Increased rates of surgery in the over-65 population are unlikely to be caused by increased prevalence of coronary artery disease and may be the result of a change in clinical attitude toward the use of CABS. This change is discussed in the context of the evidence on the effectiveness and cost-effectiveness of CABS. We conclude that there is a need to carefully monitor and evaluate the use of technologies especially in the elderly.