Early Assessment of Myocardial Viability by the Use of Delayed Enhancement Computed Tomography After Primary Percutaneous Coronary Intervention
OBJECTIVES: We sought to explore the relationship between established parameters of reperfusion and the extent of myocardial damage measured by the delayed enhancement (DE) of iodinated contrast by multidetector computed tomography (MDCT) immediately after primary percutaneous coronary intervention (PCI). Background: Early detection of myocardial viability should be valuable for risk stratification of patients with reperfused acute myocardial infarction (AMI).
METHODS: Consecutive patients without a history of previous AMI who underwent primary PCI for an ST-segment elevation AMI were examined by DE-MDCT without an additional contrast injection immediately after completion of PCI. No medication was administrated to lower the heart rate. Dose modulation lead to an approximate mean radiation dose of 5.5 mSv.
RESULTS: Thirty patients constituted the study population. Mean age was 61.4 +/- 15.6 years, 24 (80%) were men, and 4 (13%) were diabetic. Although post-procedural Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 was achieved in all patients, DE was detected in 14 (47%) patients. Age, sex, hypertension, diabetes, smoking history, serum creatinine levels, and pain duration were not associated with the presence of DE. Door-to-balloon time (DE 70.3 +/- 33.6 min vs. non-DE 98.3 +/- 70.7 min, p = 0.19) and lesion crossing time (DE 18.6 +/- 11.4 min vs. non-DE 16.4 +/- 9.6 min, p = 0.58) did not differ between groups. The TIMI myocardial perfusion grade (0 to 1 vs. 2 to 3) after stent implantation and electrocardiogram ST-segment resolution (/=50%) were associated with the presence of DE (p = 0.001 and p = 0.02, respectively). Pre-discharge left ventricular ejection fraction was lower in DE than in non-DE patients (44.6 +/- 12.4% vs. 54.1 +/- 10.3%, respectively, p = 0.05). Hospitalization days (DE 5.6 +/- 3.8 vs. non-DE 4.8 +/- 1.0, p = 0.41) and 6-month cardiac events (DE 3 of 14 vs. non-DE 1 of 16, p = 0.22) did not differ between groups.
CONCLUSIONS: Early detection of myocardial viability immediately after primary PCI by the use of DE-MDCT is related to clinical and angiographic parameters of myocardial reperfusion.