Favorable resolution of hepatic infarctions in transplanted liver after portal vein thrombosis treated by surgical thrombectomy: a case report

Perioperative thrombotic complications in liver transplantation

Although the perioperative bleeding complications and the major side effects of blood transfusion have always been the primary concern in liver transplantation (OLT), the possible cohesion of an underestimated intrinsic hypercoagulative state during and after the transplant procedure may pose a major threat to both patient and graft survival. Thromboembolism during OLT is characterized not only by a complex aetiology, but also by unpredictable onset and evolution of the disease. The initiation of a procoagulant process may be triggered by various factors, such as inflammation, venous stasis, ischemia-reperfusion injury, vascular clamping, anatomical and technical abnormalities, genetic factors, deficiency of profibrinolytic activity, and platelet activation. The involvement of the arterial system, intracardiac thrombosis, pulmonary emboli, portal vein thrombosis, and deep vein thrombosis, are among the most serious thrombotic events in the perioperative period. The rapid detection of occlusive vascular events is of paramount importance as it heavily influences the prognosis, particularly when these events occur intraoperatively or early after OLT. Regardless of the lack of studies and guidelines on anticoagulant prophylaxis in this setting, many institutions recommend such an approach especially in the subset of patients at high risk. However, the decision of when, how and in what doses to use the various chemical anticoagulants is still a difficult task, since there is no common consensus, even for high-risk cases. The risk of postoperative thromboembolism causing severe hemodynamic events, or even loss of graft function, must be weighed and compared with the risk of an important bleeding. In this article we briefly review the risk factors and the possible predictors of major thrombotic complications occurring in the perioperative period, as well as their incidence and clinical features. Moreover, the indications to pharmacological prophylaxis and the current treatment strategies are also summarized.

Concurrent hepatic artery and portal vein thrombosis after orthotopic liver transplantation with preserved allografts

In contrast to early HAT, late HAT has an insidious clinical presentation. Nevertheless, biliary and vascular reconstructions in this late setting are unlikely to improve outcome. Patent portal flow makes an important contribution to the viability of liver in case of late HAT while the allograft reconstitutes intrahepatic arterial flow through neovascularization. Concurrent HAT with PVT without immediate graft necrosis is extremely rare, and allograft and patient survival are seemingly impossible without retransplantation. In fact, hepatopetal arterial and portal venous neovascularization are known albeit obscure phenomena that can preserve posttransplant hepatic function under the extenuating circumstances of complete interruption of blood flow to the graft. We describe two such cases that developed combined HAT and PVT more than six months after OLT with perfect preservation of graft function. The survival of allografts in our cases was due to extensive hepatopetal arterial and portal venous collateralization. Simultaneous HAT and PVT after OLT are rare events and almost uniformly fatal, if they occur early. Due to paucity of such cases, however, underlying mechanisms and etiology remain elusive, and despite radiological diagnosis of these complications, there is no way to predict these events in the wake of stable graft function.