Use of donor aorta for arterial reconstruction in paediatric liver and multivisceral transplantation

Antithrombotic management and thrombosis rates in children post-liver transplantation: A case series and literature review

Thrombosis is a major postoperative complication in pediatric liver transplantation. There is marked heterogeneity in prophylactic antithrombotic therapies used, without established guidelines. This review summarizes current worldwide incidence of thrombotic events and compares antithrombotic therapies in children post-liver transplant, with comparison to our institution's experience. Of the twenty-three articles with sufficient detail to compare antithrombotic regimens, the overall incidence of thrombosis ranged from 2.4% to 17.3%. Incidence of HAT ranged from 0% to 28.1%, of HVT from 0% to 4.7%, of PVT from 1.5% to 11.2%, and of IVC thrombosis from 0% to 2.8%. Re-transplantation due to thrombosis ranged from 0% to 4.8%. Prophylactic antithrombotic therapies varied between studies, and bleeding complications were infrequently reported. Since 2010, 96 children underwent 100 liver transplants at our institution with thrombosis incidence comparable to international literature (HAT 6%, PVT 5%, IVC 1%, and HVT 0%). Re-transplantation due to thrombosis occurred in 2% and major bleeding occurred in 10%. The prophylactic antithrombotic therapies used post-liver transplantation in children remain varied. Low rates of thrombosis have been reported with antiplatelet use both with and without anticoagulation. Standard definitions and consistent reporting of bleeding complications are required, in addition to thrombosis rates, so that true risk-benefit assessment of reported regimes can be understood.

Placement of an Aortohepatic Conduit as an Alternative to Standard Arterial Anastomosis in Liver Transplantation

Background

The aim of this study was to assess the impact of placement of an aortohepatic conduit on graft and patient survival after liver transplantation (LT) in selected patients with an inadequate recipient hepatic artery (HA) for a standard arterial anastomosis.

Material/Methods

Of 331 patients who underwent deceased donor LT, 25 (7.6%) who received placement of an aortohepatic conduit at the time of transplantation were included. Clinical characteristics and outcomes, including postoperative complications, conduit patency, and graft and patient survival rates, were analyzed.

Results

All 25 patients included in this study presented a high preoperative Model for End-stage Liver Disease score (25.4±8.6; range, 6–42) and high rates of retransplantation (n=11, 44%) or previous abdominal – pelvic surgery (n=5, 20%). The observed postoperative vascular complications were portal vein thrombosis in 3 cases (12%) and anastomosis-site bleeding of the aortohepatic conduit in 1 case (4%); there was no HA thrombosis or stenosis in our analysis. With a median follow-up of 37 months (range, 0–69 months), all aortohepatic conduits were patent, and the graft and patient survival rates were 84% and 68%, respectively. The causes of death were graft failure (n=4), pneumonia (n=3), and cerebrovascular accidents (n=1).

Conclusions

Our results indicate that placement of an aortohepatic conduit is a feasible alternative to a standard arterial anastomosis in selected patients whose HA and surrounding potential inflow arteries are not suitable for standard arterial anastomosis.

Infectious aortitis in a liver transplant recipient

The development of an abdominal aortic aneurysm secondary to infectious aortitis following solid organ transplantation is a rare event that in the absence of surgical intervention, can lead to uncontrolled sepsis, catastrophic hemorrhage and death. Arterial allografts have been a viable surgical option for the past 30 years, although operative modalities have undergone a paradigm shift in recent years. We describe the first case in the literature of a liver transplant recipient who developed an infrarenal aortic aneurysm secondary to Salmonella bacteraemia, which was treated successfully with aortic allograft transplantation.

Long-term deleterious effects of aortohepatic conduits in primary liver transplantation: proceed with caution

Aortohepatic conduits provide a vital alternative for graft arterialization during liver transplantation. Conflicting results exist with respect to the rates of comorbidities, and long-term survival data on primary grafts are lacking. To identify the complications associated with aortohepatic conduits in primary liver transplantation and their impact on survival, we conducted a single-center, retrospective cohort analysis of all consecutive adult (n = 1379) and pediatric primary liver transplants (n = 188) from 1998 to 2009. The outcomes of aortohepatic conduits were compared to those of standard arterial revascularization. Adults with a conduit (n = 267) demonstrated, in comparison with adults with standard arterialization (n = 1112), an increased incidence of late (>1 month after transplantation) hepatic artery thrombosis (HAT; 4.1% versus 0.7%, P < 0.001) and ischemic cholangiopathy (7.5% versus 2.7%, P < 0.001) and a lower 5-year graft survival rate (61% versus 70%, P = 0.01). The adjusted hazard ratio (HR) for graft loss in the conduit group was 1.38 [95% confidence interval (CI) = 1.03-1.85, P = 0.03]. Notably, the use of conduits (HR = 4.91, 95% CI = 1.92-12.58) and a warm ischemia time > 60 minutes (HR = 11.12, 95% CI = 3.06-40.45) were independent risk factors for late HAT. Among children, the complication profiles were similar for the conduit group (n = 81) and the standard group (n = 107). In the pediatric cohort, although the 5-year graft survival rate for the conduit group (69%) was significantly impaired in comparison with the rate for the standard group (81%, P = 0.03), the use of aortohepatic conduits did not emerge as an independent predictor of diminished graft survival via a multivariate analysis. In conclusion, in adult primary liver transplantation, the placement of an aortohepatic conduit should be strictly limited because of the greater complication rates (notably late HAT) and impaired graft survival; for children, its judicious use may be acceptable.

Aorto-mesenteric and renal allograft transplant: a novel treatment for midaortic syndrome

Midaortic syndrome (MAS) is a rare condition characterized by stenosis of the aorta and often involving renal and visceral arteries. Current therapies include medical management of associated hypertension, and interventional procedures such as angioplasty or surgical bypass. We report a 2-year-old female with severe MAS who was initially treated with angioplasty and stents in both her aorta and superior mesenteric artery (SMA). Due to the presence of long segment stenoses, her renal arteries were not amenable to surgical reconstruction and she rapidly progressed to Stage V chronic kidney disease. The patient underwent bilateral nephrectomy and renal transplantation using a donor thoracoabdominal aorta allograft to provide inflow for the kidney as well as to bypass the nearly occluded aorta. The donor SMA was used to bypass the native SMA stenosis. Postoperatively, the patient had normalization of four limb blood pressures. She weaned from five anti-hypertensive agents to monotherapy with excellent renal function. This is the first reported case of thoracoabdominal aortic bypass using allograft aorta to address MAS. This approach allowed for successful kidney transplantation with revascularization of the mesenteric, and distal aortic circulation using allograft conduit that will grow with the child, obviating the need for repeated interventional or surgical procedures.

A new vascular approach to the modified multivisceral graft procurement

Modified multivisceral (MMV) transplantation including the stomach, pancreaticoduodenal complex and intestine requires preservation of the left gastric and splenic arteries. The previously described techniques require division of the hepatic artery proximal to the gastroduodenal artery leaving the liver transplant team with a very short and small caliber vessel. To increase MMV graft availability and provide the liver transplant team with an appropriate quality vessel, we developed the following technique. We also describe two cases where we used this method to support the technical feasibility of this procedure.

Arterial anastomosis in a pediatric patient receiving a right extended split liver transplant: a case report

We report a case of a pediatric patient who received a right-extended liver transplant. The size of the recipient hepatic artery did not match with the donor right hepatic arterial stump. Moreover, recipient arterial anatomy made the direct anastomosis difficult or at increased risk for complications. The recipient's splenic artery was then mobilized, divided and anastomosed to the donor's right hepatic artery. The spleen was preserved and revascularization through collaterals is demonstrated by Angio CT Scan. Doppler US of the transplanted liver demonstrated good flow through the liver and the patient was discharged with perfect liver function. Splenic artery is perfectly suited for hepatic artery anastomosis. The use of splenic artery is favored in particular situations as in the case of a pediatric recipient receiving a right-extended liver graft with small caliber artery.