Wall Strain Index Ratio as a Biomarker for Hemorrhagic Myocardial Infarction Mechanical Complications (RF_TH_186)

Mechanical complications following reperfused myocardial infarction (MI), such as ventricular rupture, contribute to increased morbidity and mortality in the post MI setting. Hemorrhagic transformation of the reperfused MI zone has been identified as the most severe form of reperfusion injury. However, whether hemorrhagic MIs (hMI) promote mechanical changes that contribute to an elevated risk of mechanical complications have not been investigated. The Wall Strain Index (WSI) Ratio, a validated metric of myocardial deformation linked to cardiac rupture, may serve as an essential indicator for evaluating mechanical strain differences between hMI and non-hMI. We hypothesized that the presence of hMI is associated with significantly elevated radial and circumferential WSI Ratios compared to cases without hMI.

Methods: We conducted a retrospective study (MIRON-RUPTURE NCT06450912) comprising of STEMI patients (n=181) who had undergone mechanical revascularization. A CMR protocol inclusive of breath-held, ECG-gated, 2, 3 and 4 chamber views and short-axis stacks of cine, T2*, and LGE sequences covering the whole heart, was performed approximately two days post-PCI. WSI Ratios were determined using the 2D-strain module in CVI⁴², focusing on circumferential and longitudinal strain. Statistical analyses included the Shapiro-Wilk test for parametric data and the Mann-Whitney U test for non-parametric data.

Results:

hMI patients (n=104) exhibited significantly elevated radial and circumferential WSI Ratios compared to those without hMI. Specifically, the radial WSI Ratio was about 58% higher in hMI patients (1.36±0.72) compared to non-hMI patients (0.86±0.55, p< 0.001). Similarly, the circumferential WSI Ratio in hMI patients was 103% higher (1.22±0.87 vs. 0.60±0.44, p< 0.001). The median and interquartile range (IQR) for both radial and circumferential WSI ratios indicated a significant increase in myocardial stress within the hMI group. Additional findings showed that hMI patients had increased LV EDV (122.08±33.22 ml vs. 100.78±31.92 ml, p< 0.001) and a larger infarct size (%LV): 38.69±14.27% vs. 16.20±12.11%, p< 0.001.

Conclusion:

Hearts of patients with hMI exhibited significantly higher Wall Strain Index Ratios than the non-hMI counterparts. Our findings support the notion that hMI patients carry a greater risk for mechanical complications. Accordingly, hMI patients may benefit from targeted monitoring, which may enable timely life-saving interventions in coronary care settings.