Background: Because rescue intervention may improve the outcome of patients who fail to achieve epicardial reperfusion after fibrinolytic administration for acute ST-elevation myocardial infarction (STEMI), simple noninvasive measures of infarction-related artery (IRA) patency are needed. The sum of ST-segment resolution (sum-STRES) has a high positive predictive value (PPV) for a patent IRA, but is quite time-consuming.
Methods: We retrospectively developed a very simple assessment that requires only the measurement of ST-segment deviation in a single electrocardiographic lead on a single electrocardiogram (ECG) 90 minutes after fibrinolytic administration. The ECG obtained immediately before fibrinolytic administration was reviewed as a means of selecting the single lead with the greatest ST-segment deviation. The absolute magnitude of ST deviation was measured in this lead on the 90-minute ECG. Minimal ST-segment deviation (MSTD) was defined as < or =1 mm ST deviation for inferior infarctions and < or =2 mm ST deviation for anterior infarctions. We compared the predictive value of this method with established but more complex ECG methods using data from the Thrombolysis In Myocardial Infarction (TIMI) 14 trial of low-dose fibrinolytic with full-dose glycoprotein IIb/IIIa inhibition.
Results: Of the 604 patients with an evaluable ECG and angiographic data, 383 (63%) had MSTD. The presence of MSTD had a positive predictive value (PPV) of 91% for a patent IRA (TIMI flow grade 2 or 3). Results were similar for inferior and anterior infarctions. MSTD was a means of identifying 90% of patients with complete sum-STRES. The PPV of MSTD compared favorably with that of standard measures of ST-segment resolution, but it required only a few seconds to perform.
Conclusions: The presence of MSTD at 90 minutes after fibrinolytic administration indicates a very high likelihood of IRA patency. MSTD may be helpful in identifying patients with STEMI treated by means of fibrinolytics who could safely avoid emergent coronary angiography.