The discovery of in situ thrombus attached to the patent foramen ovale channel in myocardial infarction with normal coronary arteries.

OBJECTIVE

Paradoxical embolism caused by a patent foramen ovale (PFO) is a rare cause of myocardial infarction (MI) in individuals presenting with normal coronary arteries on angiography; however, the deduction is often made due to the inability to identify the exact thrombus that penetrates the atrial septum. Previous studies using optical coherence tomography (OCT) have reported in situ thrombi attached to PFO tunnel in patients with cryptogenic stroke. However, the presence of such thrombi in patients with cryptogenic MI (without a definite cause) remains uncertain.

METHOD

We retrospectively analyzed OCT data collected from February to July 2023 on PFO tunnels in MI adults with normal coronary arteries on angiography.

RESULTS

Three patients diagnosed with cryptogenic MI and a PFO underwent OCT examination. These patients exhibited varying OCT findings. White thrombi and endocardial abnormalities in the channel were observed in two patients with MI. No thrombus or anomalous morphology on the endocardial surface was noted in the third patient. PFO closure was performed on all patients, and follow-up was completed by October 1, 2023. None of the patients reported recurrence of chest pain.

CONCLUSION

In situ thrombus was identified within the PFO channel in patients with cryptogenic MI, potentially serving as a novel etiological factor for coronary thrombosis.