TROPONIN-T, TROPONIN-I AND CREATINE KINASE-MB MASS AFTER ELECTIVE CORONARY STENTING

Objective To assess whether and to what extent elective coronary stent ing is associated with biochemical evidence of minor myocardial damage (MMD), as defined by the detection of abnormal post-procedural serum levels of one or more among the following markers of ischaemic injury: creatine kinase (CK)-MB mass, troponin T (Tn-T) and troponin l (Tn-l) . Methods Nineteen elective procedures of coronary stenting were compa red with a matched group of 25 conventional percutaneous transluminal coronary angioplasty (PTCA) procedures performed in our laboratory fro m March to June 1995. Cases with evolving or recent (<2 weeks) myocard ial infarction, chronic total occlusions and dilatation of saphenous v ein grafts were excluded. By definition, all of the patients had under gone uneventful deployment of a single Palmaz-Schatz stent, with no ch est pain and no persistent ECG changes after the procedure, Serum leve ls of CK-MB mass, Tn-T and Tn-l were determined at baseline and 6, 12 and 24 h after the procedure. The frequency of abnormal results was de termined for each marker, Baseline and peak post-procedural levels in the two groups were compared and related to procedural variables. Resu lts Baseline values were normal in all cases. The quantitative analysi s showed that post-procedural levels of each marker (including total C K) were significantly higher with respect to baseline in both groups, In the stent group, two patients had positive CK-MB mass, four positiv e Tn-T and seven positive Tn-l. Absolute changes in Tn-T and Tn-l were closely related to changes in CK-MB mass (r=0.76, P <0.0001; r=0.90, P <0.0001, respectively). Three of these patients developed clinically silent side-branch occlusion, All of them were positive for troponins and two were positive for CK-MB, No correlation was found between pro cedural variables and the results of biochemical assays, In the PTCA g roup, three patients were positive for Tn-l, whereas the CK-MB mass an d Tn-T remained constantly normal, No side-branch occlusion was observ ed, The peak CK-MB mass and Tn-l were significantly higher in the sten t group than they were in the PTCA group (3.04+/-4.1 versus 1.27+/-1.3 ng/ml, P=0.046; 0.78+/-1.17 versus 0.28+/-0.3 ng/ml, P=0.046, respect ively). This difference was no longer apparent when patients with side -branch occlusion were excluded. Conclusions In our series, Tn-l measu rement shows the highest ability to detect MMD, being positive in 37% of stent and 14% of PTCA cases. Elective coronary stenting is associat ed with greater release of CK-MB mass and Tn-l than is conventional PT CA, This finding is mainly determined by cases of side branch occlusio n, which account for most, but not all, periprocedural MMD in the sten t group.