Degree of residual stenosis of the infarct-related artery. Another variable affecting recovery of regional function after thrombolysis.

AIMS: The aim of this study was to analyse the relationship between infarct-related artery residual stenosis, assessed by quantitative coronary angiography, and left ventricular function changes during the in-hospital period in patients with acute myocardial infarction undergoing thrombolytic treatment. METHODS AND RESULTS: The study population consisted of 90 patients with acute myocardial infarction treated with thrombolysis within 6 h of the onset of symptoms. Left ventricular function was serially assessed by an echocardiographic asynergy score (before thrombolysis and pre-discharge). Left ventricular end-diastolic and end-systolic volumes were also calculated. Coronary stenosis was evaluated by computer-assisted videodensitometric analysis at pre-discharge coronary angiography. Three subgroups were identified on the basis of left ventricular function changes: 25 patients (Group A) with regional myocardial improvement (echo score from 7.5 +/- 3.5 to 4.3 +/- 3.2), 51 (Group B) with no variation in echo score (4.8 +/- 2.7) and 14 (Group C) with myocardial regional worsening (echo score from 4.4 +/- 2.1 to 8.8 +/- 2.4). Group A patients exhibited a very high incidence of infarct-related artery patency (23/25 patients, 92%) vs 71% with unchanged (Group B) and 14% (Group C) with worsening regional left ventricular function (P < 0.001). Subdivision of the study population on the basis of residual stenosis severity showed that a significant improvement in left ventricular function was present only in the subgroup with residual stenosis < 75% (echo score from 5.2 +/- 3.4 to 3.6 +/- 2.9, P < 0.001). CONCLUSION: These results support the important role exerted by complete coronary patency after thrombolysis in inducing left ventricular function recovery, and the poor functional improvement in patients with incomplete coronary patency.