Determining optimal catheterization rates

In an article by Michelle Graham and colleagues,1 an attempt was made to determine optimal catheterization rates by detecting the population rate of cardiac catheterization beyond which the yield of high-risk coronary artery disease does not rise. However, some issues are not quite clear. First, the authors did not explain why they expected to identify such a phenomenon in Canada, a country with medium catheterization rates, when they did not mention any plateau effect in countries with higher catheterization rates.

Second, the authors suggest that the highest regional average catheterization rates for men (638 per 100 000 population) and women (314 per 100 000 population) are lower than optimal catheterization rates. However, higher rates of catheterization have already been reached in several regions considered in this study for men and for women (Fig. 3 and Fig. 4 in the article),1 and there are reportedly no signs of a plateau effect. It is not clear why those higher values were not considered as the rates that are also lower than optimal catheterization rates, because that would be in accordance with the applied method of detecting an optimal rate of catheterization.