Long-term prognostic importance of patency of the infarct-related coronary artery after thrombolytic therapy for acute myocardial infarction.
BACKGROUND
After thrombolytic therapy, long-term patency of the infarct-related artery may reduce arrhythmias, limit ventricular dilatation, and provide collaterals to another infarct zone if further infarction occurs. However, independent long-term prognostic value of infarct artery patency has not been shown.


RESULTS
We followed 312 patients with first myocardial infarction treated < 4 hours after pain onset with thrombolysis (streptokinase [n = 188] or recombinant tissue-type plasminogen activator [n = 124]). At 28 +/- 11 days, cardiac catheterization was performed. Flow of the infarct-related artery was assessed by the TIMI scoring system, and a scoring system relating coronary stenoses and flow to the amount of myocardium supplied was also used. Follow-up was for 39 +/- 13 months. Cardiac death occurred in 5.8% of patients, and there were two noncardiac deaths. Revascularization was performed in 11.5% of patients. On univariate and multivariate analysis, ventricular function (ejection fraction, P = .006 and .02, or end-systolic volume index, P = .01 and .06) was the most important prognostic factor. Patency of the infarct-related artery measured as TIMI 3 flow was marginally significant on univariate analysis (P = .08) but not on multivariate analysis (P = .2). Patency was an independent prognostic factor in univariate and multivariate analysis when measured as an occlusion score (amount of myocardium supplied by an occluded artery, P = .01 and < .05). When the ejection fraction was > or = 50%, only occluded arteries supplying > 25% of the left ventricle affected prognosis adversely. If the ejection fraction was < 50%, occluded arteries supplying < 25% of myocardium also adversely affected prognosis. Treadmill exercise duration 4 weeks after infarction was the only other prognostic factor identified.


CONCLUSIONS
Ventricular function and infarct-related artery patency are independent prognostic factors after thrombolytic therapy for acute myocardial infarction.
White
H D
HD
Cardiovascular Research, Green Lane Hospital, Auckland, New Zealand.
Cross
D B
DB
Elliott
J M
JM
Norris
R M
RM
Yee
T W
TW
D006328:Cardiac Catheterization; D003331:Coronary Vessels / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D011379:Prognosis; D013300:Streptokinase / Q000627:therapeutic use*; D015912:Thrombolytic Therapy; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D014654:Vascular Patency / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology
D013300:Streptokinase; D010959:Tissue Plasminogen Activator