Evolution of gray zone after acute myocardial infarction: Influence of microvascular obstruction
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POSTER PRESENTATION
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Evolution of gray zone after acute myocardial infarction: Influence of microvascular obstruction Nilesh R Ghugre1*, Mohammad I Zia1, Perry Radau1, John J Graham2, Kim Connelly2, Alexander J Dick3, Graham A Wright1 From 2011 SCMR/Euro CMR Joint Scientific Sessions Nice, France. 3-6 February 2011 Introduction The presence of ischemia-induced microvascular obstruction (MVO) despite successful coronary revascularization, has been associated with poor functional recovery and adverse left ventricular remodeling after acute myocardial infarction (AMI). Additionally, the extent of the infarct gray zone is a strong independent predictor of post-AMI mortality. However, the evolution of gray zone after AMI has not been investigated and its relationship with MVO in terms of risk stratification is unknown. Purpose To characterize the evolution of gray zone and determine its correlation with the presence of MVO during infarct healing in patients treated with primary percutaneous coronary intervention (PCI). Methods Patients were enrolled post-PCI and underwent MRI examination on a 1.5T scanner (GE Signa Excite) at day 2, week 4 and month 6 following AMI. Cardiac function [Ejection fraction (EF), End-diastolic volume (EDV)] was evaluated using a steady-state-free-precession (SSFP) sequence in cine mode. A T1-weighted IR-GRE sequence was used for delayed-hyperenhancement (DHE) of infarcted myocardium. Infarct core (IC) and gray zone (GZ) volumes were quantified using the fullwidth-half-maximum technique as previously described; both quantities were expressed as a percentage of myocardial volume. MVO’s were manually traced and included in the infarct core calculation.
1 Sunnybrook Health Sciences Centre, Toronto, ON, Canada Full list of author information is available at the end of the article
Results Ten patients who completed MRI exams at all three time points were included in the study [mean age: 59.7±11 years; 9 males, 1 female; 4 right coronary artery and 2 left circumflex artery PCI; MVO was identified in 4 patients]. Figure 1 shows DHE images from representative patients in the MVO and non-MVO groups while Tables 1, 2, 3 summarize the corresponding quantities measured. Note that the following findings were significant: (a) infarct core was reduced in all patients by month 6; (b) MVO was resolved by week 4; (b) gray zone size relative to infarct size, GZr = 100*GZ/(GZ+IC) increased in the MVO group at month 6 while it remained stable in the non-MVO group; (d) EF was reduced in the MVO group compared to the non-MVO at all time points (p
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