Relationship between infarct size and severity measured by gated SPECT and long-term left ventricular remodelling after acute myocardial infarction

Abstract

Purpose After acute myocardial infarction (AMI), left ventricular (LV) remodelling may occur despite successful reperfusion. This study aimed to investigate by gated single photon emission computed tomography (SPECT) the longterm evolution of myocardial perfusion and LV function after AMI and to identify the predictors of LV remodelling. Methods Sixty-eight AMI patients successfully treated by primary percutaneous coronary intervention underwent 99m Tc-sestamibi gated SPECT at 1 month (baseline) and over 6-month follow-up after the acute event. LV remodelling was defined as 20% increase in LV end-diastolic volume at follow-up. Results At baseline, patients with remodelling (n=14) showed larger (infarct size 29.3±7.8%) and more transmural (infarct severity 0.28±0.10) infarctions, and reduced LV ejection fraction (35.4±5.6%), but similar LV volume indexes, compared to patients without remodelling (n=54) (infarct size 20.8±14.4%, p<0.05, infarct severity 0.40± 0.11, p<0.001, ejection fraction 44.5±9.2, p<0.001). At stepwise multivariate regression analysis, infarct severity showed the best predictive value for predicting LV remodelling (F = 5.54, p < 0.05). Using the thresholds identified by receiver-operating characteristic curve analysis, infarct size and severity detected patients with remodelling with 75% accuracy and 95% negative predictive value. Infarct resorption (defined as the defect size difference between follow-up and baseline) was comparable between patients with (−4.4±8.4%) and without remodelling (−6.8±9.4%) (p=NS). Conclusion Perfusion parameters assessed by gated SPECT in the subacute phase after successfully treated AMI correlate with changes in functional parameters at long-term followup. Infarct severity is more effective than infarct size, but both are helpful for predicting LV remodelling.

Proprotein convertase subtilisin/kexin type 9 expression is transiently up-regulated in the acute period of myocardial infarction in rat

“…Besides that, PCSK9 has been demonstrated to be expressed in human atherosclerotic plaques [35] and the study investigated the relationship between PCSK9 genotypes/haplotypes and severity of coronary atherosclerosis elucidated a modest association between minimum lumen diameter tertiles and haplotype 3 [18]. Based on these findings, we tentatively speculated that plasma PCSK9 concentration may be related to the infarct size and severity, which were predicting factors for cardiac remodeling [36] and even cardiac dysfunction. As a result, we suspected that PCSK9 may be a biomarker for the prognosis of AMI.…”

The role of infarct transmural extent in infarct extension: A computational study

“…As a result, the IZ began to dilate and demonstrate an elevated fibre strain (Figures (a) and (b)). This explains the observations from recent studies , which found a higher risk of infarct expansion events in transmurally infarcted LVs. As our results demonstrated that localized highly abnormal stress at the BZ was a result of mechanical tethering following an overstretched IZ (Figure ), the magnitude of the maximum fibre stress recorded at both the sub‐endocardial and sub‐epicardial layers was also found to have a positive correlation with average IZ fibre strain (Figure (b)).…”

Speckle tracking echocardiography derived systolic longitudinal strain is better than rest single photon emission tomography perfusion imaging for nonviable myocardium identification

“…Rest perfusion imaging score 3-4, evaluated in a semi-quantitative scale by means of the gated SPECT myocardium, can be considered a correlate of non-viable myocardial tissue, and confirming a high rest summation score represents a strongly negative prognostic predictor 5,15,[20][21][22] . While comparing the perfusion and deformation analysis, the myocardium SPECT statistically achieved, probably as a result of attenuation artifacts in the territory of the right coronary artery corresponding to the localization of the LV inferior wall, a significantly lower accuracy in predicting segments with transmural scar, in comparison with the deformation analysis (AUC 0.822 vs. 0.866, P=0.036).…”