Myoglobin, creatine-kinase-MB and cardiac Troponin-I 60-minute ratios predict infarct-related artery patency after thrombolysis for acute myocardial infarction - Results from the Thrombolysis in Myocardial Infarction study (TIMI) 10B

OBJECTIVES We examined the diagnostic performance of serum myoglobin, creat ine-kinase-MB (CKMB) and cardiac Troponin-I (cTnI) for predicting the infar ct-related artery (IRA) patency in patients receiving TNK-tissue plasminoge n activator (TNK-tPA) therapy for acute myocardial infarction (AMI) in the Thrombolysis in Myocardial Infarction (TIMI) 10B trial. BACKGROUND A reliable noninvasive serum marker of IRA patency is desired to permit early identification of patients with a patent IRA after thrombolys is. METHODS We measured myoglobin, CK-MB and cTnI concentrations in sera obtain ed just before thrombolysis (T0) and 60 min later (T60) in 442 patients giv en TNK-tPA and who underwent coronary angiography at 60 min. RESULTS Angiography at 60 min showed a patent IRA (TIMI flow grade 2, 3) in 344 and occluded IRA (TIMI flow grade 0, 1) in 98 patients. The median ser um T60 concentration, the ratio of the T60 and TO serum concentration (60-m in ratio) and the slope of increase over 60 min for each serum marker were significantly higher in patients with patent arteries compared with patient s with occluded arteries. The area under the receiver-operating characteris tic (ROC) curve for diagnosis of occlusion was 0.71, 0.70 and 0.71 for the 60-min ratio of myoglobin, cTnI. and CKMB, respectively. The 60-min ratios of greater than or equal to 4.0 for myoglobin, greater than or equal to 3.3 for CK-MB and greater than or equal to 2.0 for cTnI yielded a probability of patency of 90%, 88% and 87%, respectively. CONCLUSIONS The diagnostic performance of serum myoglobin, CK-MB and cardia c Tropinin-I (cTnI) 60-min ratios was similar. The probability of a patent IRA was very high (90%) in patients with 60-min myoglobin ratio greater tha n or equal to 4.0, and early invasive interventions to establish IRA patenc y may not be necessary in this group. Serum marker determinations at baseli ne and 60-min after thrombolysis may permit rapid triage of patients receiv ing thrombolytic therapy by ruling out IRA occlusion. (J Am Coll Cardiol 19 99;34:739-47) (C) 1999 by the American College of Cardiology.