Gender but not diabetes, hypertension or smoking affects infarct evolution in ST-elevation myocardial infarction patients - data from the CHILL-MI, MITOCARE and SOCCER trials

Abstract

Background: Infarct evolution rate and response to acute reperfusion therapy may differ between patients, which is important to consider for accurate management and treatment of patients with ST-elevation myocardial infarction (STEMI). The aim of this study was therefore to investigate the association of infarct size and myocardial salvage with gender, smoking status, presence of diabetes or history of hypertension in a cohort of STEMI-patients.

Methods: Patients (n = 301) with first-time STEMI from the three recent multi-center trials (CHILL-MI, MITOCARE and SOCCER) underwent cardiac magnetic resonance (CMR) imaging to determine myocardium at risk (MaR) and infarct size (IS). Myocardial salvage index (MSI) was calculated as MSI = 1-IS/MaR. Pain to balloon time, culprit vessel, trial treatments, age, TIMI grade flow and collateral flow by Rentrop grading were included as explanatory variables in the statistical model.

Results: Women (n = 66) had significantly smaller MaR (mean difference: 5.0 ± 1.5% of left ventricle (LV), p < 0.01), smaller IS (mean difference: 5.1 ± 1.4% of LV, p = 0.03), and larger MSI (mean difference: 9.6 ± 2.8% of LV, p < 0.01) compared to men (n = 238). These differences remained significant when adjusting for other explanatory variables. There were no significant effects on MaR, IS or MSI for diabetes, hypertension or smoking.

Conclusions: Female gender is associated with higher myocardial salvage and smaller infarct size suggesting a pathophysiological difference in infarct evolution between men and women.

Keywords: Area at risk; Diabetes; Gender; Hypertension; Sex.

Fig. 1

Comparisons of MaR, IS and MSI for gender, smoking status, presence of diabetes and history of hypertension. The number of datapoints included in each analysis is shown in white on the staples. The p-values shown are adjusted for confounders by multivariable analysis as can be seen in Tables 3, 4 and 5. MaR, IS and MSI are shown as % of left ventricular mass. MaR = Myocardium at risk, IS=Infarct size, MSI = Myocardial salvage index

Fig. 2

Example CMR images illustrating the measurement of myocardium at risk and infarct. The left image shows one time-frame from a mid-ventricular stack of a CE-SSFP cine stack. The green line denotes epicardium, the red line endocardium and the white line the borders of myocardium at risk. The right image shows the corresponding slice from a late gadolinium enhancement stack used to quantify infarct size using a previously published method [33]. In short, the yellow line shows the area of interest while the inner pink line takes intensities and partial volume effects into account. MaR in this patient was 23% of LVM, infarct size was 7% of LVM and the resulting myocardial salvage index was 70% of the MaR