Extensive Aortic Thromboembolism Due to Acquired Hypercoagulable State: An Autopsy Case Report

Archives of Pathology & Laboratory Medicine, Feb 2005 by Zhang, Ling, Hollensead, Sandra, Parker, Joseph C Jr

Aortic thrombosis rarely occurs without severe atherosclerosis, aneurysm, or cardiosurgical or traumatic state. Arterial thrombosis is commonly related to an inherited and/or acquired hypercoagulable state. A 50-year-old woman presented with diffuse abdominal pain. One day after her admission, she experienced bloody stools. Computed tomography showed multiple extensive thromboses in the aorta and superior mesentery arteries. She underwent a partial jejunoileostomy and colectomy for extensive bowel infarction. Following surgery, her condition deteriorated and she died on the fourth hospital day. At autopsy, gross examination showed 2 large thrombi (7 and 8 cm in length) in the proximal and descending (thoracic) aorta, with mild atherosclerosis. A mesenteric artery thromboembolus with extensive bowel infarction was present. Postmortem laboratory studies revealed an elevated anticardiolipin immunoglobulin G antibody level. The thrombotic state in this patient was considered multifactorial secondary to acquired risk factors, including obesity, mild aortic atherosclerosis with coronary artery disease, and presence of a high titer anticardiolipin antibody.

(Arch Pathol Lab Med. 2005;129:247-250)

Aortic thromboembolism is relatively common among patients with severe aortic atherosclerosis and/or aneurysm, as well as following cardiovascular procedures and trauma.1 The distal abdominal aorta near the bifurcation is commonly involved. Extensive aortic thrombosis in the arch and thoracic portion without severe atherosclerosis is rarely reported. In one retrospective autopsy study,2 30 cases of nonatherosclerotic and nonaneurysmal aorto-arterial thrombosis during a 14-year period were identified to investigate etiology. The study concluded that nonatherosclerotic aortic thrombosis comprised a heterogeneous group of disorders, and patients who presented with abdominal ischemia or peripheral vascular disease should be investigated for hypercoagulable states and aortic disease. A recent case report3 attributed extensive arterial thrombosis of the aorta and its distal branches in a 37-year-old man to a high circulating level of lipoprotein (a). In addition, 2 cases of aortitis detected by computed tomography (CT) and magnetic resonance imaging in patients with antiphospholipid antibodies have been described. Aortitis was suggested as the possible initial pathologic process preceding aortic thrombosis, reported as a classic complication of antiphospholipid antibody syndrome.4

Based on the Vichow triad, thrombosis is caused by an imbalance among endothelium, blood flow, and coagulation. Inherited or acquired hypercoagulable states play a key role in thrombus formation in both the arterial and venous systems. Factors that cause hypercoagulability in arteries are slightly different from veins. Common factors that involve venous thromboembolism are factor V Leiden, prothrombin mutation G20210A, and deficiencies of protein C, protein S, and antithrombin. Elevated levels of C-reactive protein, homocysteine, and lipoprotein (a) are more likely to be involved with arterial thrombosis.5 Antiphospholipid antibodies are associated with both venous and arterial thromboembolic events. A recent study6 implicated the metabolic syndrome as a cause of atherothrombosis, and another study7 coupled increasing body mass index with elevated levels of coagulation factors and inhibitors of fibrinolysis. In this case report, death was due to sepsis and bowel infarction secondary to acquired risk factor for thrombosis, including obesity, mild atherosclerosis, and an elevated level of anticardiolipin antibody of immunoglobulin (Ig) G type. A laboratory investigation for hypercoagulability had not been undertaken before death, and only a limited number of tests for hypercoagulability could be performed post mortem. Anticardiolipin antibody and molecular studies were performed on serum and whole blood samples drawn during life and incorporated in the autopsy report. The finding of an elevated anticardiolipin IgG antibody level illustrates that such testing can be beneficial in an autopsy investigation.

REPORT OF A CASE

A 50-year-old woman presented to the emergency department with abdominal pain that extended from the xyphoid to the umbilicus and had lasted for 4 hours. She complained of stabbing pains, exacerbated with urination, and nausea, vomiting, urinary urgency, and loose bowel movements. There was no history of illicit drug use, alcohol abuse, or smoking. Physical examination revealed normal vital signs, but respiratory effort was decreased and shallow. Tenderness and guarding in the right lower and left lower quadrants were noted on physical examination. No costovertebral angle tenderness was elicited. Laboratory data included the following values: white blood cells, 18 000/µL with 87.3% granulocytes; hemoglobin, 15.9 g/dL; hematocrit, 47.8%; and platelets, 240000/µL. Coagulation screening test results were within reference ranges, with a prothrombin time of 10.4 seconds with an international normalized ratio of 1.1 and an activated partial prothrombin time of 25.8 seconds. An elevated blood sugar level was found, with a blood glucose level of 215 mg/dL (11.9 mmol/L). Serum electrolyte levels and liver function test results were within normal limits. Erythrocytes, protein, and bacteria were detected by microscopic examination of urinary sediment. An abdominal CT demonstrated a small focus of calcification in the left pelvic-urethral area and chronic pyelonephritis. Abdominal plain x-ray films showed no bowel obstruction or perforation. After receiving morphine and supportive treatment, the patient improved and was discharged. Two days later, she re-presented to the emergency department with increased epigastric and right upper quadrant abdominal pain. She was unable to lie down and had chills and diaphoresis. Abdominal examination revealed diffuse tenderness without rebound pain, guarding, and decreased bowel sounds. Laboratory studies again revealed leukocytosis, with a white blood cell count of 16000/µL. Subsequent abdominal x-ray films showed dilated loops of small bowel with air-fluid levels suggestive of an ileus. She was admitted to the hospital for further investigation. A CT after admission was negative for an intra-abdominal process. Technetium Tc 99m dimethylphenylmethyl-iminodiacetic acid (HIDA scan) was scheduled on hospital day 2. Maroon blood was passed per rectum during days 1 and 2, and on hospital day 3, her temperature rose to 37.86°C with a white blood cell count of 21000/µL and bandemia. Pulse was 141/min and blood pressure was 99/46 mm Hg. She was hypoxic with abdominal distention. An abdominal CT performed in the afternoon of day 3 revealed thrombi in her descending aorta and occlusion of her superior mesenteric artery (Figure 1). An immediate exploratory laparotomy was undertaken, and 254 cm of infarcted small bowel and right colon were resected. After surgery, her condition did not improve, and the patient developed mottled legs (ecchymosis). Therapy with intravenous unfractionated heparin was started. Based on her wishes, only comfort measures were instituted. She died on the fourth day of admission.