P287Early prediction of infarct size after primary PCI by left ventricular rotation and longitudinal mechanics - which parameter is the best?


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Abstract

Background: Assessment of myocardial deformation after reperfusion in acute myocardial infarction was shown to predict LV remodeling, functional recovery of myocardium within infarct zone and is closely related to the transmural extent of the infarction. Nevertheless, power of early strain, strain rate and especially LV rotation to predict final infarct size is still challenging.Aim: examine whether longitudinal global and segmental myocardial deformation and LV rotation assessed 48h after primary PCI can predict final infarct size estimated by SPECT one month later.Methods: 29 patients with first anterior myocardial infarction successfully treated with primary PCI were examined 48h after primary PCI. Transthoracic echocardiography was done using Sequoia 256 echo machine and postprocesing was done using Syngo US workplace. Systolic and peak strain, systolic and diastolic strain rates (SR S; SR E and SR A) were measured as indices of longitudinal LV function in apical 4-, 2- and 3 chamber views. Global and territorial (for LAD territory) strain and strain rates were calculated. Rotations of LV base and apex were measured (rotation angle and rotation velocities), LV twist and LV torsion were calculated. SPECT imaging with 99mTc-MIBI was done a month after index event and defect in myocardial perfusion measured as percent of the total myocardial surface.Results: both global and territorial peak strains were closely related to SPET perfusion defect (r= - 0.68, p=0.001 and r=- 0.76, p=0.004). Global and territorial systolic SR correlated well with SPET perfusion defect (r=-0.59, p=0.007 and r=-0.68, p=0.022), whereas global SR-E showed less strong correlation (r= 0.42, p=0.05). The strongest correlation SPECT perfusion defect had with apical rotation angle (r= -0.80, p<0.001), LV twist (r=- 0.77, p<0.001) and LV torsion (r=- 0.74, p< 0.001). In multivariant logistic regression analysis that includes global peak longitudinal strain, global SR S, LV EF 48h after the primary PCI, peak CK-Mb mass and LV apical rotation angle, LV apical rotation angle (beta=-0.615, p=0.012) and peak CK-Mb mass (beta=0.365, p=0.013) were independent predictors of infarct size.Conclusion: LV apical rotation, as well as territorial and global longitudinal strain and strain rates 48h after reperfusion therapy in patients with first anterior myocardial infarction well correlate with size of infarction as determined by SPECT a month later. The best correlation had LV apical rotation. These parameters could be of clinical value for risk stratification early after myocardial infarction.

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