Prognostic significance of myocardial salvage obtained by gated SPECT myocardial perfusion imaging using scoring evaluation method early after primary percutaneous coronary intervention in ST-segment-elevation myocardial infarction

Abstract

Purpose Myocardial salvage (MS) and myocardial salvage index(MSI) assessed by Gated SPECT myocardial perfusion imaging (GSMPI) have demonstrated prognostic significance in ST-segment-elevation myocardial infarction(STEMI). However, this method requires GSMPI after tracer injection before percutaneous coronary intervention(PCI), so make it limited in clinical practice. This study aims to obtain the MSI by simple GSMPI early after primary PCI (PPCI) in STEMI , evaluate the predictive significance of MSI in efficacy of PCI and major adverse cardiovascular events (MACEs). Apply the scoring evaluation method innovatively different from the previous method, and confirm the former’s advantage. Methods 62 patients with STEMI, who underwent GSMPI after PPCI. MS and MSI were obtained by scoring and the number evaluation method,respectively. Left ventricular ejection fraction (LVEF) before discharge and 6 months after PCI were estimated by cardiac ultrasound.Patients whose LVEF increased by at least 20% compared to baseline were defined as PCI-effective group. Compare the MS ,MSI and their prognostic significancein PCI efficacy between the two evaluation methods. Patients were divided into two groups according to the median MSI(0.27), over a median follow-up period of 270(128-366) days, estimate the prognostic significance of MSI on MACEs. Results The MS and MSI were relevant [ r(MS)=0.491, r(MSI)=0.779, P< .05], but significant different by the two methods (P < .01). MSI by the scoring method showed the stronger prognostic value in PCI efficacy with AUC of 0.793, sensitivity: 71.40%, specificity: 73.70% than the number method with AUC of 0.634, sensitivity: 43.80%, specificity: 94.40% (all P<.05). COX prevalence of MACEs was significantly higher in the <median MSI group than≥median MSI [HR 0.20; 95% ci, 0.04–1.10; P <0.05].ROC analysis showed that MSI predict MACEs with an area under the curve (AUC) of 0.870, sensitivity: 73.70%, specificity: 87.50%(P<0.01).There was a obvious linear correlation trend between MSI and LVEF before discharge by Jonckheere-Terpstra test( P< .05). Conclusion MSI obtained from an simple GSMPI after re-perfusion on scoring evaluation method is a reliable prognostic indicator which provides feasible way to predict the PPCI efficacy and MACEs in STEMI patients.