Four-dimensional flow magnetic resonance imaging assessment in a patient with antiphospholipid syndrome and sinus of Valsalva thrombus: a case report

Background: A thrombus in the sinus of Valsalva (SOV) with a native aortic valve is a rare aetiology of type 2 myocardial infarction. To the best of our knowledge, no previous report has evaluated blood flow dynamics in the SOV of a patient who experienced an SOV thrombus. Case summary: A 72-year-old woman presented to our hospital with chest pain. Based on electrocardiogram and echocardiography findings, she was diagnosed with ST-elevation acute coronary syndrome (ACS) due to left main trunk (LMT) occlusion. Emergency coronary angiography revealed embolization in the distal left anterior descending artery. Her symptoms improved after catheter engagement in the LMT. Echocardiography revealed an abnormal mass (20 × 20 mm) in the left coronary cusp, which appeared to intermittently occlude the LMT. Emergency surgical removal revealed that the thrombus was adherent to the aortic wall at the left SOV. Histopathological examination confirmed a fresh red thrombus. The patient was discharged on warfarin 13 days postoperatively. Time-resolved three-dimensional cine phase-contrast magnetic resonance imaging (4D-flow MRI) was performed to assess blood flow. She was subsequently diagnosed with antiphospholipid syndrome. Discussion: 4D-flow MRI showed reduced blood flow velocity in the left SOV compared with the other sinuses, without evidence of excessive wall shear stress. These findings may represent a 'second hit' of antiphospholipid syndrome. Further investigation is warranted to elucidate the mechanisms underlying SOV thrombosis. It is important to consider SOV thrombus as an aetiology of ACS, even in patients without history of thrombosis or prior aortic valve surgery.