Abstract 675: MDCT Immediately After Primary Percutaneous Coronary Intervention for Acute Myocardial Infarction is Useful in Assessing Infarct Extent
Introduction: Imaging studies to determine myocardial infarct size (IS), such as MRI and nuclear testing, are difficult to perform in the emergency setting when the patient is unstable. Delayed enhanced MDCT has recently emerged as a viable alternative to measure the transmural extent of enhancement and IS.
Hypothesis: In the present pilot study, we sought to evaluate the feasibility and reliability of MDCT in determining IS in patients who underwent primary percutaneous coronary intervention (PCI) for first acute ST-elevation myocardial infarction (STEMI).
Methods: Seven consecutive patients presenting with acute STEMI underwent delayed enhanced MDCT immediately after successful primary PCI without injection of an additional contrast media. Infarct size (IS) was determined as the total volume of myocardium showing delayed enhancement. The extent of initial ST-segment elevation and cardiac biomarker levels (before PCI and serially up to 36 hours) were determined.
Results: The mean symptom-to-door and door-to-balloon times were 82.0±67.2 and 60.2±6.8 minutes, respectively. The total volume of contrast media used during PCI was 186±43mL, and the delay between the last contrast injection and the CT scan was 15.0±5.7 minutes. The IS by MDCT was 21.1±22.4mL. The initial peak ST-segment elevation was 4.2±3.0 mm, and the peak serum levels of creatine kinase, creatine kinase-MB, and troponin-I were 2,373±1,884 U/L, 127±106 U/L, and 82±76 ng/mL, respectively. Among these, only the level of troponin-I significantly correlated with IS (r=0.964, p=0.036). No significant correlation was observed between IS and the levels of high-sensitivity CRP and N-terminal pro-B-type natriuretic peptide.
Conclusion: Delayed enhanced MDCT immediately after primary PCI for acute STEMI is effective in assessing infarct extent without the need for an additional contrast media injection and may come into use in many pivotal clinical trials.