Cross-modality analysis of left ventricular function and volume in patients with st-segment elevation myocardial infarction: impact of infarct patterns
Authors: Cramer M , Georgieva LG , Nienhaus FN , Haberkorn SH , Wischmann PW , Jung CJ , Kelm MK , Boenner FB 
Published: July 2021

Abstract

Funding Acknowledgements
Type of funding sources: Public hospital(s). Main funding source(s): Sonderforschungsbereich 1116, University Düsseldorf

Background
Left ventricular (LV) function is considered of major importance to estimate prognosis of patients with ST-segment elevation myocardial infarction (STEMI) [1]. Although transthoracic echocardiography (TTE) after STEMI is recommended to assess for LV function and identify patients at high risk for rehospitalisation due to heart failure, Cardiovascular Magnetic Resonance (CMR) is still considered the gold standard for an adequate quantification of volumes, function and infarct size (IS) [2]. In addition, unenhanced TTE has been shown to underestimate LV function [3]. It is complicating that parameters such as IS and area-at risk (AAR) are thought to further deteriorate prognosis [4,5].
Purpose
To test the hypothesis that cross-modality 2D/3D analyses using TTE, CMR and cineventriculography are comparable for the determination of LV-function in STEMI and that infarct patterns influence the determination of LV-function and volumes across modalities.
Methods
In a group of 70 patients after STEMI, estimation of LV function and volumes was performed by biplane cineventriculography during acute catheterization, biplane (2D) CMR 28 ± 16 hours (1 day) as well as 2D/3D-CMR and TTE 114 ± 31 hours (5 days) post STEMI. 3D-TTE after STEMI was only performed in a subset of 36 patients respectively. IS and AAR were assessed by T2-weighted and contrast enhanced CMR (1.5T) as percentage of the LV mass.

Results
Both, 2D- and 3D-, LV ejection fraction (LVEF) were comparable between the single modalities. Stroke volume (SV) and LV end-diastolic volume (LVEDV) were underestimated when comparing 2D- to 3D-CMR and when comparing TTE/cineventriculography to CMR.
Correlating IS to the difference of 2D- and 3D-CMR, higher IS/AAR did not alter previous results, except from a fairly increased difference in SV (R = 0.3). For 2D-TTE versus 2D-CMR, higher IS/AAR increased differences in LVEDV (IS & AAR: p &lt;0.001 both, R = -0.58, R=-0.54). For 3D-TTE and 3D-CMR, IS and AAR increased the difference in LVEF (p = 0.009, R = 0.50; p &lt; 0.001, R = 0.60) and LVEDV (p = 0.021, R=-0.5; p = 0.027, R=-0.46). A general linear model (GLM) for repeated measures including IS as covariate supported this finding by showing a significant interaction effect between the imaging modalities (TTE/CMR) for LVEF estimation and IS. AAR increased the difference in LVEF comparing cineventriculography and 2D-CMR as well (p = 0.001, R = 0.47). This was again supported by a significant interaction effect as detected by the GLM.

Conclusions
There is good agreement between LVEF analysis across dimensions (2D and 3D) and different modalities (TTE, cineventriculography and CMR) whereas the comparison of SV and LVEDV is hampered. However, with increasing IS or AAR, LVEF differences between modalities increase and 3D-CMR, if available, or alternatively 3D-TTE should be used for the most accurate estimation of LVEF.