LOW INCIDENCE OF MINOR MYOCARDIAL DAMAGE ASSOCIATED WITH CORONARY STENTING DETECTED BY SERUM TROPONIN-T COMPARABLE TO THAT WITH BALLOON CORONARY ANGIOPLASTY

The use of the serum troponin T (TnT) level as a means of assessing mi nor myocardial injury, which affects the long-term prognosis, has not been fully clarified in patients with coronary artery disease in whom a coronary stent has been implanted. We measured the TnT level to dete rmine the incidence of myocardial damage associated with Stent implant ation. A total of 29 patients who underwent successful stent implantat ion (stenting group) were studied and compared with 45 patients who un derwent successful coronary balloon angioplasty during the same period (balloon angioplasty group). The serum TnT level was measured by enzy me immunoassay 36 hours after the stenting or balloon angioplasty. The activities of serum creatine kinase (CK) and its isoenzyme MB (CK-MB) were measured by a modified Rosalski method and an immunoinhibition m ethod, respectively, before, immediately after, and 6, 12, and 24 hour s after the procedure. Elevation of the TnT level was found in 3.4% (1 /29; 0.35 ng/ml) of the patients in the stenting group, and in 8.9% (4 /45; 0.75 +/- 0.21 ng/ml) of those in the balloon angioplasty group. E levation of the CK and CK-MB activities was found in 3.4% (1/29; 163 I U/l) and 0%, respectively in the stenting group, and 15.5% (7/45; 375 +/- 143 IU/l) and 4.4% (2/45; 24 and 49 IU/l), respectively, in the ba lloon angioplasty group. TnT elevation was not invariably accompanied by CK or CK-MB elevation, or by angiographically visible side branch o cclusion. For TnT, CK-MB activity and CK activity, there was no signif icant difference between in the incidence of elevation in the balloon angioplasty group and that in the stenting group. In summary, the inci dence of myocardial damage associated with stent implantation seems to be low and comparable to that associated with balloon angioplasty. De spite the low incidence, measurement of the serum TnT level in additio n to CK-MB measurement is essential in assessing minor myocardial dama ge.