Bowel ischemia caused by a giant thrombus in the ascending aorta. A case report

Introduction

It is known that an ascending aortic thrombus is very rare and studies about it are relatively scanty. To date, the etiology of this disease is still unclear. An ascending aortic thrombus can well cause fatal embolic complications in organs by the dropped emboli from this thrombus. Thus, it is often clinically identified from organ embolism, including symptoms such as acute myocardial infarction and cerebral and left renal infarctions. ¹ Clearly, a better understanding of it and its complications is of great clinical importance for accurate diagnosis and improved treatment of this rare condition.

Herein, we report a case of giant organized thrombus in the ascending aorta, which caused the complications associated to ileal arteries embolization.

Case report

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. The study protocols in the patient were approved by the Ethics Committee of the Huazhong University of Science and Technology.

A 47-year-old man with a history of hypertension and renal calculus complained of epigastric pain for 15 h and was transferred to our hospital. The patient had sudden onset of severe abdominal cramps that continued. Physical examination found obvious tenderness in epigastric area. The patient’s vital signs were in the normal range. Electrocardiogram (ECG) and chest X-ray (CXR) showed no abnormalities. He had a history of smoking: consumption of one pack per day for the past 25 years. An abdominal computed tomography (CT)-scan showed superior mesenteric artery embolism (SMAE). Considering the possibility of intestinal necrosis, an exploratory laparotomy was performed immediately after admission. During the operation, we found that the middle ileum, of about 1 m long, was obvious edema and there were no signs of either intestinal necrosis or intestinal tumor. After the surgery, the patient no longer felt any pain in the epigastrium.

In order to find out the source of the emboli, a computed tomography angiography (CTA) of thoracic and abdominal aorta was performed. It demonstrated that: (1) there was a 6.2 × 1.3  cm strip mass attached to the anterior wall of the ascending aortic root in the direction of blood flow (Figure 1A); (2) there were also two strip masses (length of 2.1 cm and 5.6 cm, respectively) in two ileal arteries (Figure 1B), and the distal branch of the SMA was normal. OPEN IN VIEWER

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Figure 2.

Hematoxylin and eosin staining showing atherosclerotic changes that occurred around the site of the giant mass (magnification: 100 x).

In addition, echocardiogram confirmed the presence of a strip mass attaching to the anterior wall of the ascending aortic root. The CT-scan showed the same results as CTA. Neither intracardiac thrombus nor valvulopathy was detected. CT-scan and B-scan ultrasonography of the kidneys did not detect any anomalies. The patient had no familial history of thromboembolic events or diabetes. The circulating levels of various biomarkers (routine blood tests; live function test; blood coagulation function test; D-dimer; routine rheumatological test, troponin) determined by blood tests were all in normal ranges.

We then performed a surgery to remove the strip mass attached to the ascending aorta and replaced the latter with a synthetic graft under deep hypothermic circulatory arrest. During the surgery, the right atrium and right femoral artery were cannulated to establish cardiopulmonary bypass.

The excised specimen was confirmed to be an organized thrombus. Our pathological examination revealed that the atherosclerotic changes occurred around the site of the giant mass, which was mainly constituted by the blood-coagulating substances (Figure 2).

The patient was in good conditions after the operation. The vital signs were normal. ECG, CXR, and routine blood test revealed no abnormalities. After being discharged from the hospital, the patient received a long-term treatment with oral antiplatelet agent (aspirin 100 mg/day) and no recurrence of aortic thrombosis was detected during two years of postoperative follow-up (Figure 3). OPEN IN VIEWER

Discussion

Despite that the ascending aortic thrombosis is relatively rare, adequate attention should be paid to this condition due to the high mortality rate associated with its major embolic complications. Here, we report a case of bowel ischemia due to ileal arteries embolization induced by a giant ascending aorta thrombus.

Our patient suffered from epigastric pain caused by the SMA thromboembolism due to the ascending aortic thrombus. We performed an initial exploratory laparotomy to determine the location and nature of SMAE. If a chest CT-scan had been performed before this operation, the exploratory laparotomy might be able to avoid. We proposed that an ascending aortic thrombus should be considered as one of the possible causes of systemic embolism.

In our case, we started anticoagulation therapy once the SMAE was detected, and the pain got significant relief. It indicated that preoperative short-term anticoagulation therapy might be able to alleviate the syndromes of embolization in other organs.

We initiated the anticoagulation therapeutic regimen prior to the exploratory laparotomy which might exacerbate the SMAE by the cardiopulmonary bypass during the surgery. However, prolonged anticoagulation therapy can cause fragmentation of the thrombus, ¹ whereupon we therefore performed an urgent ascending aorta replacement, followed by a long-term postoperative treatment with aspirin (100 mg/day).

Several methods are available for the treatment of the aortic thrombus, including both simple thrombectomy and aortic resection. Our decision to adopt anticoagulation therapy was primarily based on a previous report about the successful thrombolytic treatment of a giant thrombus in the ascending aorta. ¹ Because the possibility of an intra-aortic tumor could not be entirely ruled out in our patient, we performed an ascending aortic replacement.

Multiple factors are related to arterial thrombus, such as arteriosclerosis, malignant tumors, and hemostatic disorders, including heterozygous factor V Leiden mutation or protein S deficiency.^2–5 In our case, no family history of coagulation disorders was identified, but the patient was a smoker with a history of hypertension. Smoking may be a secondary risk factor for embolic complications. The pathological examination unraveled some mild atherosclerotic changes around the site of the giant mass. Atherosclerosis caused by intimal injury may be another predisposing factor for embolic complications. However, the exact mechanisms for the formation of giant thrombus in the ascending aorta are not fully understood.

In conclusion, our report demonstrated a rare cause of the SMAE detected by CTA. This situation reinforced the fact that the ascending aortic thrombus should be considered as one of the causes of systemic embolism. Accurate diagnosis and timely surgery for an ascending thrombus are highly recommended to avoid fatal thromboembolic complications in patients and preoperative short-term anticoagulation therapy could be beneficial for patients who have associated symptoms.