Non-invasive detection of early infarct vessel patency by resolution of ST-segment elevation in patients with thrombolysis for acute myocardial infarction - Results of the angiographic substudy of the Hirudin for Improvementof Thrombolysis (HIT)-4 trial

Aims The purpose of this study was to validate ST segment resolution as a n on-invasive marker for patency of the infarct-related artery 90 min after t he start of streptokinase therapy in patients with acute myocardial infarct ion. Methods and Results In the HIT-4 angiographic sub-study, 447 patients with acute myocardial infarction less than or equal to6 h received 1.5 million I U streptokinase. Angiograms of the infarct vessel were obtained after 90 mi n and 12-lead ECGs at baseline and after 90 min. The best cut-off points fo r a correct prediction of 90 min infarct vessel patency (TIMI 2/3 flow) and complete patency (TIMI 3) were 30% ST resolution and 40% ST resolution, re spectively (specificity 68%; and 69%, sensitivity 76% and 75%). Prediction of infarct vessel patency by ST resolution in steps of 10%, displayed a gra dual increase in patency rates. Patients with greater than or equal to 70% ST resolution (n=70) had a 92% probability of TIMI 2/3 flow, while <30% ST resolution (n=172) was associated with the absence of TIMI 3 how in 84% of patients. Conclusions Despite fairly good sensitivities and specificities the predict ion of infarct vessel patency by ST resolution in the individual patient is limited. However, patients with <greater than or equal to>70% ST resolutio n are likely to have a patent infarct artery and <30% ST resolution predict s epicardial vessel occlusion or, since persistent ST elevation reflects th e existing ischaemic myocardial injury, absence of myocardial perfusion. (E ur Heart J 2001; 22: 769-775, doi:10.1053/euhj,2000,2290) (C) 2001 The Euro pean Society of Cardiology.