Torrent of Troponin
“The River Eddy Whirls”
–The Lady of Shalott, Lord Alfred Tennyson (1842)
In this issue of Circulation: Cardiovascular Interventions, Herrmann et al1 report data from a contemporary registry from the Mayo clinic. The study examined the relationship between the magnitude of periprocedural myonecrosis with percutaneous coronary intervention (PCI), measured simultaneously with contemporary troponin T (TnT) and creatine kinase-myocardial band (CK-MB), with 3-month postprocedural survival and determine whether there was a threshold value for TnT at which prognosis was significantly affected. Importantly they only included patients with normal baseline biomarker levels.
Article see p 533
Of the 5268 patients (43%), 1142 (22%) patients after PCI developed TnT or CK-MB elevation >1× upper limit of normal (ULN). Post PCI elevations tended to be small; the peak level was 0.05 ng/mL (median; interquartile range, 0.02–0.15) for TnT and 10.8 ng/mL (median; interquartile range, 7.3–19.5) for CK-MB. This should be no surprise to the field and highlights the critical role of making sure that the baseline TnT value is normal before the procedure.2
Three-month mortality was 0.9% in patients with and 0.4% in those without any level of postprocedural TnT elevation (P=0.01). The optimal TnT cutoff value for 3-month mortality prediction was 0.25 mg/mL, that is, 25× ULN, but this level was found in only 7% of patients. In respect of prognostic bioequivalence, a cutoff value of 25× ULN for TnT and 5× ULN for CK-MB provided similar information.
In a multivariate model that adjusted for the Mayo Clinic risk scores, postprocedural TnT elevation remained associated with 3-month all-cause death (hazard ratio [HR] per doubling of TnT, 1.24 [1.08–1.43]; P=0.003) and cardiovascular death (HR per doubling of TnT, 1.26 [1.04–1.54]; P=0.02). Although any level of elevation of CK-MB was associated with higher 3-month mortality, independent of …