FACTORS ASSOCIATED WITH THE RELEASE OF CARDIAC TROPONIN-T FOLLOWING PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY

Background: Recent studies have suggested that immunoassay of cardiac troponin T (cTnT) provides a more sensitive measurement of myocardial necrosis than creatine kinase MB (CK-MB) mass concentration. Hypothesi s: The purpose of this study was to compare the release of cTnT and CK -MB isoenzyme in patients undergoing percutaneous coronary angioplasty and to investigate the clinical, procedural, and angiographic correla tes of abnormal elevations of both of these markers. Methods: Total cr eatine kinase (total CK), CK-MB, and cTnT levels were measured immedia tely before and 12 h following Intervention in 110 patients, including 100 consecutive patients undergoing coronary angioplasty and 10 contr ol patients undergoing diagnostic cardiac catheterization. All patient s had normal levels of all three markers at baseline. A postinterventi on total CK level > 225 U/l, an increase in CK-MB MB > 5.0 ng/ml, and/ or an increase in cTnT > 0.01 ng/ml were considered indicative of myoc ardial injury. Results: Coronary angioplasty was successfully performe d in all 100 patients without emergency bypass surgery or death, altho ugh six patients required emergent placement of an intracoronary stent for threatened closure. Eight patients demonstrated an abnormal incre ase in total CK, including six who were undergoing primary angioplasty for an acute myocardial infarction. One of these patients sustained a Q-wave infarction. Post angioplasty, 18 patients had elevations of bo th CK-MB and cTnT, 23 had elevations of only cTnT, and the remaining 5 9 patients had elevations of neither. AU patients with CK-MB elevation also had cTnT elevation. Neither serologic marker increased in the di agnostic catheterization control patients. In comparison with patients without postintervention cTnT rise, patients with abnormal cTnT level s had a higher incidence of complex lesion morphology (p<0.01) and int ra coronary thrombus (p less than or equal to 0.0001) prior to coronar y angioplasty, and a higher incidence of coronary dissection (p less t han or equal to 0.01), abrupt closure (p less than or equal to 0.05): and side-branch occlusion (p less than or equal to 0.01) during angiop lasty. In patients with elevation of both cTnT and CK-MB, postinterven tion CK-MB levels were 12-fold higher and cTnT levels were 21-fold hig her than in patients with isolated elevation of only cTnT (p<0.01). Co nclusions: These data indicate that >40% of patients undergoing corona ry angioplasty have evidence of minor degrees of myocardial damage, as evidenced by cTnT release. High-risk coronary lesions and both minor and major complications of angioplasty are associated with cTnT releas e. cTnT appears to be a more sensitive marker of myocardial injury tha n CK-MB under these circumstances. In comparison with isolated cTnT ri se, elevation of both CK-MB and cTnT may be indicative of greater leve ls of myocardial injury.