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We present two patients with acute rapidly enlarging rectus sheath hematomas. Case 1 developed the hematoma following ultrasound-guided liver biopsy, while in case 2 the hemorrhage was spontaneous. Both were anti-coagulated. Computed tomography of the abdomen with arterial phase scans were valuable in defining the sites of hemorrhage and planning endovascular treatment. The radiological findings and intervention are discussed with review of the relevant literature.

Introduction
Most patients described in the literature with spontaneous rectus sheath hematomas are on a form of medical anticoagulant therapy or have a bleeding diathesis.^1–3 The indication for angiography includes persistent bleeding and hemodynamic instability, despite reversal of anticoagulation.¹⁰ The majority of these indicated cases were treated by transarterial embolization (TAE).^1,2,4,5

Case 1
A 67-year-old male presented to the emergency department with a swollen left lower limb and confirmed deep venous thrombosis (DVT) following Doppler study. Later in the admission, an ultrasound-guided biopsy of a liver mass in segment 5 was performed with a 22G needle, having ceased the heparin infusion 4 hours prior. A total of 4 passes were performed, and then therapeutic clexane was recommenced.

Three days following the biopsy, the patient complained of a sudden onset of sharp pain at the percutaneous biopsy site. Examination revealed a tender swelling in the left hypogastrium.

A portal venous phase computed tomography (CT) abdomen performed demonstrating a contained leftsided rectus sheath hematoma measuring 9 cm x 56 cm x 12 cm with a fluid hematocrit level and active extravasation of contrast within it. The contrast could be traced on axial images along the pathway of the superior epigastric artery. Anticoagulation was discontinued and an urgent conventional angiogram arranged.

An Optease (Johnson and Johnson, New Brunswick, New Jersey) inferior vena cava (IVC) filter was placed in the infrarenal IVC through the right transfemoral approach. An angiogram was performed through right transfemoral access. The left internal mammary artery was cannulated using a 4 Fr vertebral glide catheter (Terumo, Somerset, New Jersey). Active contrast extravasation was seen from a branch of the left superior epigastric artery, corresponding to the site of hematoma. The branch was selectively cannulated using a Progreat catheter (Terumo). Coil embolization was performed using 2 Tornado coils (3 mm x 2 cm, 0.018”, Cook, Bloomington, Indiana). Gel foam slurry was injected into the left superior epigastric artery. The check angiogram confirmed cessation of contrast extravasation. The patient’s recovery was uneventful.

Case 2
A 77-year-old patient taking clopidogrel (Plavix, Bristol-Meyers Squibb/Sanofi Pharmaceuticals, New York, New York) for atrial fibrillation presented to the emergency department with a rapidly growing mass in the right anterior abdominal wall. He had a dry cough for 10 days and developed left upper quadrant pain that worsened for 4 days prior to presentation. Pain associated with the mass increased to severe. On examination, a tender mass was found in the right upper quadrant, with rebound and guarding present. The coagulation profile was normal.

Triple Phase CT with plain, arterial, and venous scans were performed, demonstrating a large left upper abdominal wall rectus sheath hematoma measuring approximately 5 cm x 11 cm x 10 cm. Arterial phase images with curved reconstructions demonstrated active extravasation arising from the left inferior epigastric artery. This was used for planning for angiographic intervention.

Right femoral retrograde access was obtained. The left inferior epigastric artery, arising from the left common femoral artery, was selectively cannulated using a VS2 catheter (Cook). A pseudoan-eurysm, measuring 7 mm x 6 mm, was identified from a small branch of inferior epigastric artery. Using a Progreat microcatheter (Terumo), 4 Tornado coils (3 mm x 2 cms, 0.018”, Cook) were placed across the origin of the branch leading into the aneurysm. There was no filling of the pseudoaneurysm on the angiogram.

Discussion
Approximately 10 cases in 7 articles in the literature describe cases of rectus sheath hematomas. Other than in trauma or iatrogenic settings, all of these patients were anticoagulated. Five cases were spontaneous and 5 were traumatic or iatrogenic. Most presented as a rapidly growing tender anterior abdominal wall mass. All the cases in the literature originate from the inferior epigastric artery. There are no previously reported cases arising from the superior epigastric artery.

The popular use of anticoagulation therapy in the pharmacological management of multiple conditions increases the rate of spontaneous hematomas.⁸ The rectus sheath and the psoas muscles represent the most common sites of spontaneous bleeding in patients undergoing anticoagulation therapy.⁷ Little is known about the pathophysiology of spontaneous extraperitoneal hemorrhage. It has been hypothesized to be caused by diffuse small vessel arteriosclerosis.¹¹

In hemodynamically stable patients, the common management currently continues to be conservative by suspension of the anticoagulation treatment, correction of the anticoagulation state, volume resuscitation and supportive measures.^3,9 The indication for angiography includes persistent bleeding and hemodynamic instability, despite reversal of anticoagulation.⁸

The majority of cases were treated by TAE.^1,2,4,5Bleeding location on angiography relate closely with CT findings.³ There is little information regarding the procedure time and planning using CT prior to angiography. Although there are inadequate numbers in this case report, one case used computed tomography angiogram (CTA) and the other a post-contrast CT. The second angiography case was technically easier with CTA planning. CTA may be effective in planning for localization in conventional angiography and reduces the length of procedure time and, thus, may reduce morbidity and complications.

CT is also useful in identifying the epigastric vessels prior to needle biopsies or other invasive procedures.¹⁰ In retrospect, the superior epigastric artery of case one may have been avoided prior to liver biopsy.

Conclusion
Transarterial embolization is a safe and effective treatment to manage rapidly enlarging hematomas in the anterior abdominal wall in indicated cases.

Acknowledgement. The authors would like to thank Dr. R. Sebben, MB, BS, FRANZCR from The Queen Elizabeth Hospital for his support and guidance in producing this article.