The traditional diagnosis of myocardial infarction (MI) used the World
\nHealth Organization definition and required the concentration of a
\ncardiac biomarker to be above twice the upper limit of normal.
\nHowever, more recent guidelines have defined a troponin level above
\nthe 99th percentile of normal as being diagnostic of MI.<\/p>\n
Using data from the AMIS (Acute Myocardial Infarction in Switzerland)
\nregistry, Urban investigated the outcomes of those patients with the
\n“classic” definition of MI (CK or CK-MB above the upper limit of
\nnormal, or troponin T [TnT] >0.1\u03bcg\/L) compared to those with the
\n“new” definition of myocardial infarction (TnT>0.01\u03bcg\/L).<\/p>\n
Overall 489 patients were diagnosed with the new criteria (a “new”
\nMI) and 8701 with the old (a “classic” MI). \u00a0In-hospital mortality
\nwas 3.5% in the “new” group and 6.7% in the “classic” group
\n(p=0.004). \u00a0In as subset of patients with a longer follow-up,
\nmortality at 3 and 12 months was 1% for “new” compared to 1.6% for
\n“classic” at 3 months, and 5.6% compared to 4% at 12 months (p=NS).<\/p>\n
By lowering the troponin threshold needed for the diagnosis of MI, the
\nnumber of patients with this diagnosis will increase. \u00a0In this study
\nthis population was represented by the “new” cases, and despite
\nless aggressive treatment in hospital they had a better short term
\nprognosis than “classic” cases. \u00a0However, the 3- and 12-month risk
\nwas the same in both patients, suggesting that even a minor
\ntroponin leak identifies a group of patients at high-risk in the long
\nterm.<\/p>\n