Myocardial injury on cardiac magnetic resonance imaging with late gadolinium enhancement and factors associated with myocardial scar size in patients with acute myocardial infarction

Aim. To study quantitative and morphological parameters of myocardial injury using cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement in patients with acute myocardial infarction and to identify factors associated with scar zone size.
Material and methods. The single-centre observational study included 202 patients (91% men) with ST-segment elevation (86%) and non-ST-segment elevation (14%) MI, aged 57 (50; 61) years. Primary percutaneous coronary intervention was performed in 136 patients (67%), and pharmacoinvasive revascularisation was performed in 66 patients (33%). On days 7–10, examination was performed, including echocardiography (Echo) and magnetic resonance imaging (MRI) of the heart with contrast. Based on cardiac MRI results patients were divided into three groups: Group 1 — 43 patients with LV scar burden of <5% or its absence: Group 2 — 83 patients with LV scar burden of 5-20%; Group 3 — 76 patients with  LV scar burden of >20%. One-factor logistic regression analysis was used to identify variables that help diagnose different scar sizes.
Results. Patients in Group 3 were more likely to have type 2 diabetes mellitus compared to Group 2. Non-ST-segment elevation MI was more common in Group 1 compared to Groups 2 and 3 (p1-2,3 <0.05); pathological Q waves were diagnosed in Group 3 12.4 and 1.6 times more often than in Groups 1 and 2, respectively (p1-2,3;2-3 <0.001). It was also noted that Group 1 received thrombolytic therapy more quickly than Group 3 (p=0.032). Echo data revealed a predominance of indexed left ventricular (LV) volume parameters and the LV myocardial mass index in Group 3 compared to Groups 1 and 2, while the ejection fraction (EF) was minimal in Group 3 (p1,2-3 <0.05). MRI results revealed additional differences in the end-systolic volume index and LVEF between Groups 1 and 2. According to cardiac MRI results, the ratio of peri-infarction heterogeneous zone mass to the scar mass in Group 1 was 123.3 (81.3; 182.1) %, in Group 2 — 77.2 (57.8; 112.8) %, in Group 3 — 42.9 (29.4; 56.4) % (p1-2,3;2-3 <0.05). In Group 1, reperfusion injury was detected in only one patient (2.3%), in Group 2 — in 34.9% of cases, and in Group 3 — in 78.9% (p1-2,3;2-3<0.05). According to the regression analysis results, the following general significant indicators were found for the absence of a scar zone or SM/LVMM <5% and SM/LVMM >20%: high-sensitivity troponin I, N-terminal pro-brain natriuretic peptide; according to EchoCG data — end-systolic volume index, EF, LV myocardial mass index; according to MRI data — indexed volume indicators, EF, indexes of local contractility and global contrast.
Conclusion. A small scar burden had no adverse effect on cardiac morphological or functional parameters in patients with acute myocardial infarction who had no detectable scar or only a minimal scar burden (scar mass/left ventricular myocardial mass <5%) on late gadolinium enhancement cardiac MRI. Type 2 diabetes mellitus and pathological Q waves on electrocardiography, elevated blood levels of high-sensitivity cardiac troponin I and N-terminal pro-B-type natriuretic peptide, as well as reduced left ventricular ejection fraction and increased left ventricular volumes assessed by echocardiography and cardiac magnetic resonance imaging, were associated with a greater scar burden (scar mass/left ventricular myocardial mass >20%).

1. Greulich S, Mayr A, Gloekler S, et al. Time-Dependent Myocardial Necrosis in Patients With ST-Segment-Elevation Myocardial Infarction Without Angiographic Collateral Flow Visualized by Cardiac Magnetic Resonance Imaging: Results From the Multicenter STEMI-SCAR Project. J Am Heart Assoc. 2019;8(12):e012429. DOI:10.1161/JAHA.119.012429.

2. Scalise RFM, De Sarro R, Caracciolo A, et al. Fibrosis after Myocardial Infarction: An Overview on Cellular Processes, Molecular Pathways, Clinical Evaluation and Prognostic Value. Med Sci (Basel). 2021;9(1):16. DOI:10.3390/medsci9010016.

3. Richardson WJ, Clarke SA, Quinn TA Holmes JW. Physiological Implications of Myocardial Scar Structure. Compr Physiol. 2015;5(4):1877-909. DOI:10.1002/cphy.c140067.

4. Sillanmäki S, Hartikainen S, Ylä-Herttuala E. Review of Myocardial Ischemia, Scar, and Viability Estimation with Molecular Magnetic Resonance Imaging. Biomedicines. 2024;12(8):1681. DOI:10.3390/biomedicines12081681.

5. Averkov OV, Harutyunyan GK, Duplyakov DV, et al. 2024 Clinical practice guidelines for Acute myocardial infarction with ST segment elevation electrocardiogram. Russian Journal of Cardiology. 2025;30(3):6306. (In Russ.)DOI:10.15829/1560-4071-2025-6306.

6. Averkov OV, Harutyunyan GK, Duplyakov DV, et al. 2024 Clinical practice guidelines for Acute coronary syndrome without ST segment elevation electrocardiogram. Russian Journal of Cardiology. 2025;30(5):6319. (In Russ.)DOI:10.15829/1560-4071-2025-6319.

7. Chalise U, Becirovic‐Agic M, Lindsey ML. The cardiac wound healing response to myocardial infarction. WIREs Mech Dis. 2023;15(1):e1584. DOI:10.1002/wsbm.1584.

8. Stone GW, Selker HP, Thiele H, et al. Relationship Between Infarct Size and Outcomes Following Primary PCI: Patient-Level Analysis From 10 Randomized Trials. J Am Coll Cardiol. 2016;67(14):1674-83. DOI:10.1016/j.jacc.2016.01.069.

9. Lee DC, Albert CM, Narula D, et al. Estimating Myocardial Infarction Size With a Simple Electrocardiographic Marker Score. J Am Heart Assoc. 2020;9(3):e014205. DOI:10.1161/JAHA.119.014205.

10. Tereshchenko SN, Duplyakov DV, Uskach TM, et al. Potential of thrombolytic therapy in the early period of ST-elevation myocardial infarction. Expert consensus. Russian Journal of Cardiology. 2025;30(6):6417. (In Russ.) DOI:10.15829/1560-4071-2025-6417.

11. Boytsov SA, Shakhnovich RM, Tereschenko SN, et al. Features of the Reperfusion Therapy for ST-Segment Elevation Myocardial Infarction According to the Russian Registry of Acute Myocardial Infarction — REGION-IM. Kardiologiia. 2024;64(2):3-17. (In Russ.) DOI:10.18087/cardio.2024.2.n2601.

12. Tiller C, Reindl M, Holzknecht M, et al. Biomarker assessment for early infarct size estimation in ST-elevation myocardial infarction. Eur J Intern Med. 2019;64:57-62. DOI:10.1016/j.ejim.2019.03.001.

13. Prastaro M, Pirozzi E, Gaibazzi N, et al. Expert Review on the Prognostic Role of Echocardiography after Acute Myocardial Infarction. J Am Soc Echocardiogr. 2017;30(5):431-43. DOI:10.1016/j.echo.2017.01.020.

14. Bendary A, Afifi M, Tawfik W, et al. The predictive value of global longitudinal strain on late infarct size in patients with anterior ST-segment elevation myocardial infarction treated with a primary percutaneous coronary intervention. Int J Cardiovasc Imaging. 2019;35(2):339-46. DOI:10.1007/s10554-018-1498-7.

15. Oleinikov VE, Salyamova LI, Donetskskaya NA, Vdovkin AV. Effect of ischemic injury characteristics on left ventricular systolic function in patients with acute myocardial infarction. Russian Journal of Cardiology. 2023;28(8):5516. (In Russ.) DOI:10.15829/1560-4071-2023-5516.

16. Oleynikov VE, Salyamova LI, Chernova AA, et al. Impact of reperfusion timing and methods on myocardial structure and function in ST-segment elevation myocardial infarction. Russian Journal of Cardiology. 2026;31(2):6809. (In Russ.)DOI:10.15829/1560-4071-2026-6809.

17. Vora KP, Kumar A, Krishnam MS, et al. Microvascular Obstruction and Intramyocardial Hemorrhage in Reperfused Myocardial Infarctions: Pathophysiology and Clinical Insights From Imaging. JACC Cardiovasc Imaging. 2024;17(7):795-810. DOI:10.1016/j.jcmg.2024.02.003.