Evaluation of coronary artery patency using cardiac markers.

The availability of a reliable marker of infarct-related artery (IRA) patency status may permit early identification of patients with patent IRA, for whom repeat thrombolysis or rescue percutaneous coronary intervention (PCI) may not be necessary. We found that the ratio of serum myoglobin levels obtained before and 60-min after initiation of thrombolytic therapy provides a useful indication of the IRA patency status. When the 60-min myoglobin ratio was >4.0, the probability of a patent IRA was 90%, suggesting that emergency coronary angiography to determine their IRA status may be unnecessary when this pattern of release of myoglobin is observed. The low specificity of this marker could be addressed by its combined use with other noninvasive tests such as ST-segment resolution and the persistence of chest pain at the time of angiography.