Management of splenic artery aneurysms in liver transplant recipients

Abstract

We read with great interest the recent article1 describing Moon et al.'s experience with splenic artery aneurysms (SAAs) in adult living donor liver transplant recipients. The authors retrospectively reviewed 44 liver transplant recipients with SAAs out of 310 patients. Interestingly, portosystemic shunts were present in all patients, with the diameter of these collaterals being the only significant factor for the presence of SAAs. Three patients presented with a ruptured aneurysm in the postoperative period, and 2 of these had undergone splenic artery ligation at the time of transplantation. After this experience, the authors changed their policy, and they now recommend aggressive treatment of SAAs, either surgical or radiological, within 24 hours of transplantation, before or afterward. Nevertheless, other facts are also worth noting in this report. First, despite the recommendation of proximal and distal ligation of the splenic artery for a unique extrasplenic aneurysm, only proximal ligation was possible in 6 patients, and 2 of them suffered an SAA rupture. Second, 32 patients with SAAs ranging from 10.5 to 25 mm were not treated during the study period; they had no complications, and they experienced a significant reduction of the mean aneurysm diameter after 1-year of follow-up. Our experience is similar to the latter finding. From February 1996 to May 2009, 786 liver transplants were performed in our institution with whole grafts from deceased donors. In a retrospective analysis, we found 7 recipients with SAAs diagnosed during the transplant assessment. All patients had a unique SAA in the distal third of the splenic artery with a diameter ranging from 10 to 30 mm. No prophylactic treatment was indicated, and no complications occurred. After a median follow-up of 106 months (range = 5-132 months), the size of the SAAs decreased from 30 to 20 mm in 2 patients, whereas the others remained unchanged. The incidence of SAAs in our series was probably underestimated because of the retrospective analysis; however, we have had no cases of urgent reoperation or death due to SAA rupture. Although there seems to be a general consensus to treat symptomatic SAAs, asymptomatic SAAs greater than 20 mm, and those in liver transplant candidates,2, 3 this appears to be based only on reports of complicated aneurysms, whereas the natural history of untreated SAAs in transplant patients remains poorly understood. Three reports of untreated SAAs in no transplant setting were revised in a recent report, and only 1 of 191 patients suffered spontaneous rupture after a mean follow-up that ranged from 15 to 75 months.2 Nevertheless, abdominal surgery is considered to be a risk factor for SAA rupture,4 and the reported incidence of this complication is 2% to 4% in the posttransplant period.1, 3 Moreover, with respect to the treatment of SAAs in liver transplant candidates during the perioperative period, some facts must be considered: (1) splenectomy during liver transplantation might be difficult and a cause of severe intraoperative complications1; (2) distal splenic artery ligation for single extrasplenic aneurysms is usually difficult to accomplish because of technical difficulties; (3) proximal ligation alone might be enough to prevent the rupture of extrasplenic aneurysms but not the rupture of hilar and intrasplenic ones, which unfortunately are the most common1; and (4) aneurysm embolization or complete arterial embolization in hilar and multiple aneurysms seems to be very effective, although complications are not uncommon.1, 3, 5 In summary, the incidence of SAA rupture in liver transplant patients is not high, adequate surgical treatment is frequently challenging, and arterial splenic embolization is not free from complications. In this scenario, the aggressive treatment of all liver transplant candidates with SAAs is debatable. In our opinion, more studies are needed to determine the risk factors related to the rupture of SAAs in liver transplant recipients and to define a group of patients who may benefit from preventive treatment. Until then, we are very reluctant to treat all SAAs in liver transplant candidates but instead would prefer to treat them only when they are symptomatic, are greater than 30 mm, or show enlargement during a close follow-up with repeated computed tomography angiograms. Mikel Gastaca*, Alberto Ventoso*, Andrés Valdivieso*, Jorge Ortiz de Urbina*, * Hepatobiliary Surgery and Liver Transplantation Unit University Hospital of the Cross at Bilbao Baracaldo, Vizcaya, Spain.