Discussion
A mural thrombus of the thoracic aorta, that develops in the absence of
pre-existing aortic disease, is a rare clinical finding with potentially
devastating complications. Thrombus formation in the ascending aorta is
an even more unusual event reported hardly before in patients with a
non-aneurysmatic aorta12. The etiology of thrombus
formation in a macroscopically normal aorta is not well understood. A
correlation with underlying malignant disease, hypercoagulable
disorders, endothelian disorders, steroid therapy, blunt trauma or even
iatrogenic causes has been suggested345. In the
presented case routine laboratory tests showed no abnormal findings and
a coagulation disorder was excluded postoperative. Screening for cancer
remains negative and the patient didn‘t had any B-symptoms. In the
presented case, an endothelial lesion caused by a plaque rupture or the
rupture of a vasa vasorum seems to be the most obvious origin of the
thrombus formation.
As this remains a rare disease, there is no consensus on prognostic
assessments or optimal treatment strategy. Therapeutic options include
therapeutic anticoagulation, open surgical thrombectomy and endovascular
treatment with stentgrafts. Medical treatment (anticoagulation,
thrombolysis) may lead to complete dissolution of the thrombus in most
of the cases. However, a careful patient selection is necessary and
embolization remains the major concern with this
approach6. Open surgery with segmental aortic
resection provides optimal treatment in patients with local neoplasms or
endothelial lesions of the thoracic aorta and eliminates the risk of
embolic events. In the case of endothelial damage, the affected segment
should be replaced, or if localized, like in our case, a patch repair
should be used to cover the thrombogenic spot. Cardiovascular bypass
should be established by cannulation of the subclavian or alternative
femoral artery, in order to prevent cerebral thromboembolism.
Preparation of the aorta before cross clamping is performed in no-touch
technique. The endovascular approach is a much less invasive option than
open surgery. However, the anatomical conditions must be suitable for
stent release and there is an ongoing risk of distal embolism during
intervention and wire manipulation.
Patient management includes a detailed patient history, clarification of
coagulation disorders and tumor screening. A peripheral pulse status and
possibly a Doppler sonography are part of the initial examination.
Aortic CTA is recommended as first-choise examination because of
availability and high sensitivity. For further evaluation of thrombus
morphology, and to exclude intracardiac thrombi, a transthoracic or
transesophageal echocardiography should be performed. A cranial CT is
recommended in case of neurological symptoms. The therapy strategy is
based on the thrombus morphology, location, patient age/ concomitant
diseases and patient’s wishes. In case of a mobile, pedunculated mass
with localization in the ascending aorta open surgical thrombectomy
should be considered, due to high thromboembolic risk. The indication
for surgery should be made particularly generous in young patients. In
case of thrombus localization in the descending aorta endovascular stent
graft exclusion seems to be an effective and safe option. It can be
considered as well for failed medical and open surgical approach. Mural,
broad based thrombi, behind the outlet of the left subclavian artery may
be suitable for initial medical therapy, especially in high risk
patients.