Angiographic frame counts 90 minutes after streptokinase predict left ventricular function at 48 hours following myocardial infarction

Objective - To assess whether the 90 minute corrected thrombolysis in myocardial infarction frame count (CTFC) in the infarct related artery predicts left ventricular function at 48 hours in patients with myocardial infarction treated with aspirin, streptokinase, and either heparin or Hirulog. Design and setting - Analysis of 251 patients with acute myocardial infarction enrolled in the international, multicentre Hirulog early reperfusion/occlusion (HERO-1) trial, who underwent both 90 minute coronary angiography and 48 hour left ventriculography. Main outcome variables - The CTFC was determined in the infarct related artery 90 minutes after starting intravenous streptokinase (1.5 x 10⁶ U over 30 to 60 minutes), and compared with indices of left ventricular function assessed by contrast ventriculography at 48 hours. Results - A CTFC of ≤ 27 frames (previously reported mean + 2 SD in coronary arteries of patients without acute infarction) occurred in 29% of infarct related arteries, and was associated with a lower infarct zone mean chord score (-2.06 ν -2.54, p = 0.01), a lower fraction of chords > 2 SD below normal (37% ν 51%, p = 0.005), and trends towards higher left ventricular ejection fractions (60.9% ν 58.2%, p = 0.11) and lower end systolic volumes (50.1 ml ν 55.9 ml, p = 0.23). A CTFC of ≤ 40 at 90 minutes occurred in 50% of infarct related arteries, and was associated with a significantly lower mean chord score (-2.20 ν -2.60, p = 0.02), a smaller fraction of chords > 2 SD below normal (41% ν 52%, p = 0.025), a smaller end systolic volume (49.1 ml ν 59.3 ml, p = 0.02), and a higher left ventricular ejection fraction (60.4% ν 56.5%, p = 0.03). Conclusions - The 90 minute CTFC predicts left ventricular function at 48 hours following streptokinase. The CTFC associated with better ventricular function may be higher than values determined from a non-infarct population.