Interpreting Myocardial Infarction Analyses in ISCHEMIA

Separating Facts From Fallacy

Raffaele De Caterina; David L. Brown


Eur Heart J. 2021;42(31):2986-2989. 

In This Article

Prognostic Implications of Myocardial Infarctions in Ischemia

For an MI to be clinically and prognostically significant, its prevention by revascularization should result in a mortality reduction. There has been much commentary regarding the greater impact on late mortality for spontaneous compared with periprocedural MIs (with little consideration of the excess mortality associated with late procedure-related MIs), yet in ISCHEMIA there was absolutely no differential effect of treatment strategy on all-cause and cardiovascular mortality at 5 years[1] (Graphical abstract). The only reasonable explanation for this observation is that the carry-over effects on mortality of the excess periprocedural (Types 4a and 5) and late procedure-related (Types 4b and 4c) MIs in the invasive arm (224 − 44 = 180) perfectly balanced the carry-over effects of the 80 (186 − 106) excess spontaneous MIs in the conservative arm. The finding that periprocedural MI according either to primary or secondary definitions in ISCHEMIA would not be associated with later mortality[15] is counterintuitive based on the above considerations, and likely the result of a type II statistical error—claiming the absence of an effect because of the inability to show it in statistical terms.