Diagnosis of Hemorrhagic Myocardial Infarction with Post PCI Cardiac Troponin-I: Implications for CMR-Guided Therapy for Hemorrhagic Myocardial Infarction

Revascularization for ST-elevation myocardial infarction (STEMI) carries a high risk (~50%) for intramyocardial hemorrhage (IMH). IMH is identified to be the worst form of reperfusion injury (CCS-AMI Stage IV) and patients with IMH carry the highest risk for Major Adverse Cardiovascular Events in the post-infarction period. While CMR is currently the only standard for diagnosing hemorrhagic myocardial infarction (hMI), it is challenging to perform CMR in every STEMI given the limitations in access (particularly in community hospitals) and patient stability. To overcome these limitations, we hypothesized that post-primary PCI high-sensitivity cardiac troponin-I concentrations ([hs-cTn-I]) can accurately diagnose hMI rapidly, allowing for selective use of CMR for further characterization of IMH, particularly for assessment of novel therapeutics targeting hMI.

Methods:

We performed a multicenter randomized trial (MIRON-TROP) in revascularized STEMI patients (n=207), which involved serial [hs-cTn-I] measurements at 16 time points within 48 hours post-primary PCI followed by CMR at approximately 72 hours post-PCI for validation. The study evaluated the diagnostic performance (sensitivity, specificity and diagnostic accuracy) of post-PCI [hs-cTn-I] levels for identifying hMI and non-hMI.

Results:



Post-PCI hs-cTn-I levels accurately identified hMI patients within 1 hour of PCI, demonstrating a sensitivity of 0.94 and specificity of 0.89. The diagnostic performance was further supported by an AUC of 0.95 when compared to CMR findings. Prior to PCI, hs-cTn-I levels in hMI and non-hMI patients were not significantly different (p > 0.2). In the hMI group, hs-cTn-I peaked 6.5 hours earlier (4.02 ± 0.78 hours) and 11-fold higher (348.16 ± 37.07 ng/mL) than in the non-hMI group, where the peak occurred at 10.52 ± 0.67 hours with a maximum of 30.95 ± 3.57 ng/mL.








 


Conclusion:

Post-reperfusion [hs-cTn-I] is a reliable and broadly deployable blood marker for accurate detection of hemorrhagic MI. It is ideally suited for rapid identification of patients most suited for CMR-guided clinical trials targeting hMI, particularly with respect to patient selection/recruitment. The proposed strategy is expected to benefit ongoing and future trials evaluating novel therapies.

This figure compares post-PCI hs-cTn-I levels between hMI and non-hMI patients, along with coronary angiography and CMR findings. hMI patients (red box) exhibit significantly higher hs-cTn-I levels (356.74 ± 262.45 ng/mL), while non-hMI patients (blue box) show lower levels (37.93 ± 37.22 ng/mL). The left panel shows coronary angiography with white arrows indicating obstructive CAD before and after reperfusion in both hMI and non-hMI patients. The right panel shows CMR with LGE and T2* imaging. The red contour represents the endocardium, and the green contour represents the epicardium, with arrows pointing to the infarcted regions.