Intramyocardial Hemorrhage Leads to Higher MACE Rate by Increasing Myocardial Infarction Volume in Patients with STEMI.

Background And Aims: Whether IMH can directly cause persistent myocardial necrosis after reperfusion therapy in STEMI patients is still unclear. We conducted a prospective study to compare the cardiovascular parameters in patients with STEMI with and without IMH to explore the potential correlations between IMH and poor outcomes.

Methods And Results: We prospectively enrolled 65 consecutive patients with newly diagnosed STEMI admitted to the CCU of the Second Xiangya Hospital of Central South University between April 2019 and November 2021, all of whom underwent primary PCI. Of these, 38 (58.5%) and 27 (41.5%) patients were in the IMH-absent and IMH-present groups, respectively. At a mean time of 5-7 days after reperfusion therapy, the volume of MI measured using LGE sequence was larger in STEMI patients with IMH than in patients without IMH (34.2 ± 12.7 cm vs 21.1 ± 13.1 cm, <0.001). HsTNT levels were significantly higher in the IMH-present group than in the IMH-absent [2500.0 (1681.5-4307.0) pg/mL vs 1710.0 (203.0-3363.5) pg/mL, =0.021] group during hospitalization. The LVEF measured using CMR in the IMH-present group was lower than that in the IMH-absent group (30.7 ± 9.8% vs 42.3 ± 11.0%, < 0.001). The rate of MACE at 12 months in IMH-present group was significantly higher than in the IMH-absent group (9/27 VS 2/38, = 0.012).

Conclusion: IMH can lead to further expansion of MI volumes in patients with STEMI, resulting in lower LVEF and higher MACE rate in the post-discharge follow-up.