Abstract 11097: Evaluation of Micro-vascular Obstruction after Acute Myocardial Infarction with Delayed Enhancement Cardiac MR Imaging compared with Mismatch of BMIPP and thallium SPECT

Abstract

<Background> Cardiac magnetic resonance (CMR) imaging is a useful modality in assessing myocardial structural changes in patients with acute myocardial infarction (AMI). The hypo-enhanced regions within the hyper-enhanced infarct areas detected by CMR imaging are considered to be areas of micro-vascular obstruction (MO). The mismatched findings obtained by BMIPP and thallium SPECT reportedly suggest the prevalence of myocardial viability. We aimed to evaluate whether MO could be an early predictor for irreversible myocardial damage in patients with AMI compared with BMIPP and thallium dual SPECT findings.

<Methods> Target population consisted of forty-four patients with initial AMI, who underwent primary percutaneous coronary intervention. CMR imaging was performed 9.1 ± 3.0 days after PCI. BMIPP and thallium dual SPECT were acquired 9.6 ± 3.0 days after PCI. MO was defined by CMR imaging. Patients were divided into 2 groups as follows : MO group (n=24) and non-MO group (n=20). Scintigraphic defect scores were calculated with a 17-segment model with a 5-point scoring system on the polar maps. The mismatch score was calculated by the subtraction of the total sum of the BMIPP and thallium defect scores in each segment (sigma BMIPP defect score minus sigma thallium defect score).

<Results> The thallium defect score was significantly greater in the MO group than in the non-MO group (8.2±6.0 vs 22.2±8.3, p<0.001). The BMIPP defect score was significantly greater in the MO group than in the non-MO group (11.9±7.9 vs 23.3±8.4, p<0.001). The mismatch score was significantly greater in the non-MO group than in the MO group (1.1±3.8 vs 3.6±3.6, p=0.02).

<Conclusions> Perfusion-metabolism mismatch is greater in AMI patients not showing MO. Our results suggest that MO is an important finding for the early detection of irreversible myocardial damage after AMI.