EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Key words : Abscess, Cirrhosis, Drainage, Endovascular, Portal venous thrombosis

Splenic artery aneurysms are more common in patients with liver cirrhosis and portal hypertension than in the general population, with incidence ranging between 7% and 17%.^1,2 Multiple factors, including arteriovenous shunting and collateral formation that lead to increased splenic blood flow, are probable causes for the higher incidence of splenic artery aneurysms in this population. The feared complication of a splenic artery aneurysm is rupture, which is seen in 3% to 10% of cases and may carry a 40% mortality rate.^1,3 In the immediate perioperative period after a liver transplant, the risk of rupture and risk of mortality are both elevated. The Society for Vascular Surgery recommends intervention for pseudoaneurysms, aneurysms >3 cm, aneurysms in women who are pregnant or of childbearing age, and aneurysms with growth rate >0.5 cm/y. Endovascular treatment is the preferred initial approach for splenic artery aneurysms in anatomically suitable cases because this limits patient morbidity and has been shown to be an effective alternative to open surgery.^2,4

There is a paucity of data regarding the management of complications after splenic artery embolization in the liver transplant population. We present a case of a liver transplant patient who underwent embolization and developed significant complications that were successfully managed with noninvasive radiological techniques.

A 38-year-old man with a history of biliary atresia who had previously been treated with a Kasai hepatoportoenterostomy at 6 weeks of age developed cirrhosis and portal hypertension and subsequently underwent a successful orthotopic liver transplant (deceased donor, unrelated to recipient). Thirty months later, he presented to the emergency department with a several-week history of left-side flank pain. Computed tomography scan revealed a stable, enlarged spleen with a known fusiform splenic artery aneurysm measuring 3.6 × 1.9 cm that was noted to be increasing in size (Figure 1A). He underwent endovascular splenic artery embolization of the superior arterial pole with coils and Onyx Gelfoam (Figure 1B and 1C). Flow was preserved in the lower pole branch of the splenic artery. A week later, he developed left upper quadrant abdominal pain, and computed tomography scan showed near complete splenic infarction and thrombosis of the main, right, and left portal vein, the superior mesenteric vein, and the splenic vein (Figure 2A). He had a mild leukocytosis of 11.5 × 10⁴/µL and slightly elevated total and direct bilirubin (1.7 and 0.7 mg/dL, respectively). He underwent catheter-directed tissue plasminogen activator infusion to the superior mesenteric vein and left portal vein (1 mg/h tissue plasminogen activator) with improvement in vascular patency (Figure 2B and 2C). He remained on intravenous therapeutic heparin for 24 hours after the procedure. His leukocytosis resolved, and subsequent tests revealed normalized liver function. He continued a single-agent tacrolimus immunosuppression regimen and transitioned to oral rivaroxaban for discharge.

He returned to the emergency department 3 weeks later with continued left flank and left upper quadrant abdominal pain and fever. In the emergency department, he was afebrile with stable vital signs and white blood cell count of 8.0 × 10⁴/µL. Computed tomography scan showed a new 21 × 16 × 7-cm splenic abscess with rim enhancement and internal foci of air (Figure 3A). He was started on empiric piperacillin/tazobactam. A percutaneous drain was placed, and fluid was cultured and grew Propionibacterium avium. Antibiotic therapy was modified to intravenous vancomycin. A week later, repeat computed tomography scan indicated an appropriately placed drain with a reduction in abscess size. He was discharged and returned home with intravenous vancomycin and with the drain in place. He had remained afebrile without leukocytosis or liver function test abnormalities throughout the hospitalization. The patient is now 4 months postembolization, and serial computed tomography scans have continued to demonstrate a patent portal vein and decreasing size of the abscess with drain management.

Splenic artery aneurysms are a rare but potentially deadly sequelae of cirrhosis and portal hypertension. Treatment options for splenic artery aneurysms after liver transplant include percutaneous endovascular intervention with either embolization coils or covered stents versus surgical aneurysm resection with or without splenectomy. A systematic review of endovascular, open, or conservative treatment in 1321 patients found a lower risk of 30-day mortality for endovascular versus open (0.6% vs 5.1%) but a higher risk of reinterventions for endovascular versus either open or conservative management.⁵ In the setting of a previous liver transplant, endovascular treatment is favored.

Data on complications after splenic artery embolization after liver transplant are sparse. Splenic artery embolization can cause a decrease in portal vein flow, which predisposes to the development of portal vein thrombosis. In addition, infarction of the spleen can lead to an increased platelet count, which may contribute to the risk of thrombosis development. Similar to our patient, there have been reports of other patients with extensive portal vein thrombosis after endovascular embolization of the splenic artery.⁶ Some authors have reported thrombolysis to be an effective treatment; certainly thrombolysis has been established as an option for the management of acute portal vein thrombosis.⁷ In our liver transplant patient, the reestablishment of portal flow was important for the success of thrombolysis.

In a review of partial splenic embolization for splenomegaly in cirrhotic patients, splenic abscesses occurred in 0% to 6.3% of patients. Patients with >70% embolization (by splenic volume) had the highest rates of postprocedural complications.⁸ The treatment of splenic abscesses in liver transplant recipients is further complicated by immunosuppression. A review of 16 liver transplant patients who underwent partial splenic embolization for persistent hypersplenism found postprocedural splenic abscesses in 19%.⁹ There is an increased risk of infectious complications after splenic artery embolization in liver transplant patients. A multicenter review of splenic artery aneurysm for blunt trauma found 6 of 140 patients (4%) developed splenic abscesses and 5 of the 6 patients required salvage splenectomy.¹⁰ A study of splenic artery embolization for hemorrhage secondary to pancreatitis found a high incidence of postembolization abscess (18/26, 70%). All patients underwent percutaneous drainage, but 8 patients (44%) eventually required splenectomy for persistent infectious symptoms.¹¹ Although there are no data to address the postembolization splenic abscesses in immunocompromised patients, we support a minimally invasive approach with percutaneous drainage and antibiotics as an initial treatment, given the high surgical morbidity of open splenectomy in a liver transplant recipient. Patients with persistent infectious symptoms, decompensation, or requirement for multiple percutaneous procedures may benefit from subsequent splenectomy.

Our case report highlights the successful minimally invasive, endovascular management of extensive portal vein thrombosis and splenic abscess after splenic artery embolization in a liver transplant patient. The management of these complex liver transplant cases requires close collaboration among a multidisciplinary team.

Volume: 20 Issue: 2 February 2022

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