A giant free-floating thrombus in the ascending aorta caused by radiofrequency ablation of premature ventricular contractions

CASE REPORT

A 48-year-old female was admitted to our emergency department with sudden chest pain and abdominal pain for 2 days. She had a history of radiofrequency ablation of premature ventricular contractions 20 days before. The patient was not taking any antiplatelet therapy, which she had explicitly refused. Laboratory tests revealed elevated levels of cardiac hypersensitivity troponin I（5.22 ng/ml）and ultrasensitive C-reactive protein（25.81 mg/l）and an erythrocyte sedimentation rate of（46 mm/h）. The electrocardiogram suggested an abnormal Q wave and T wave inversion or depression in leads II, III and aVF (Fig. A). Emergency ultrasound suggested an isoechoic mass approximately 2.7 × 1.2 cm attached at the right coronary aortic cusp, extending into the aortic intracavitary ? with a floating attitude, and no other abnormalities of cardiac structure, function and valve systems. Triple-rule-out computed tomography showed a pedunculated mass measuring 19.2 x 12.3 mm in the ascending aorta (Figure, B, C), a left ventricular inferior wall myocardial infarction (Figure, D) and bilateral acute renal infarction. The patient underwent emergency removal of the surgical mass under extracorporeal circulation. During the procedure, a 3.0 x 1.5 cm mass was attached at the root of the right coronary aortic cusp. Postoperative treatments included ventilator assistance, maintenance of cardiac function, vasodilation, blood volume adjustment, stabilization of the internal fluid environment and anti-infection and symptomatic support. A postoperative histopathologic examination confirmed that the mass was a thrombosis with inflammatory infiltration (Figure, E, F). The postoperative course was uneventful. No recrudescence or concomitant visceral or vascular embolism was observed. The patient was discharged with dual antiplatelet agents.

DISCUSSION

Free-floating thrombus in the aorta is defined as a nonadherent portion of a thrombus floating within the aortic lumen. Free-floating thrombus of the aorta without an aneurysm or dissection is rare, with an incidence rate of about 0.45% [1]. The most common locations for floating thrombi are the aortic isthmus, the descending thoracic aorta and the lower abdominal aorta [2]. Free-floating thrombus of the ascending aorta is a rare disease entity and is most commonly caused by coagulopathy, immunological disorders, malignancies, aortic atherosclerosis, aneurysmal dilatation, trauma, steroid use and substance abuse [3, 4]. They are prone to break off, thus carrying a potential risk for embolic events with catastrophic thrombotic events, such as ischaemic stroke, acute myocardial infarction and peripheral arterial embolism [5]. To our knowledge, making an accurate diagnosis is still challenging, and there is no consensus on therapeutic recommendations.

We report the case of a 48-year-old female who had myocardial and bilateral renal infarctions due to emboli from a giant thrombus in the ascending aorta, likely caused by a catheter injury. After radiofrequency ablation of premature ventricular contractions and no antiplatelet agents, the pathomechanism of this injury may be the result of trauma related to the retrograde crossing of the aortic valve. The patient was treated surgically. She had an uneventful postoperative course with no recurrent thrombus or embolic event during the follow-up period. Our case highlights the fact that ultrasound and computed tomography angiography are important in diagnosing the floating aortic thrombus. An aggressive surgical approach is recommended to prevent further embolic episodes.

CONCLUSION

Free-floating thrombus in a non-aneurysmal and non-atherosclerotic ascending aorta is a rare disease entity that carries the potential risk of distal embolization with catastrophic consequences. The mechanism underlying aortic thrombus formation is complex and likely multifactorial. Clinicians should be careful to identify the aetiology. Transthoracic echocardiography or computed tomography angiography is a useful examination technique for patients with aortic thrombi. Thrombectomy can effectively reduce the risk of recurrent embolism.

Data Availability Statement

The data underlying this article will be shared on reasonable request to the corresponding author.

Conflict of Interest: None declared.

REFERENCES

Author notes