Vascular Catastrophes Following Pancreatic Transplantation: Is Systemic Anti-Coagulation Necessary?

Abstract

Introduction: Vascular complications present a major challenge in Pancreas Transplantation (PT) and are a significant contributor to both morbidity and mortality. Because of relatively low portal pressures, systemic anti-coagulation has evolved to become a vital and routine part of early post-operative management of PT and is essential in minimizing graft thrombosis. This conversely however increases the risk of bleeding and haematoma negatively impacting on patient outcome. We aimed to describe our 10 year experience with PT and identify the impact of vascular complications on outcome in an attempt to establish the relative risks of thrombosis and haemorrhage on outcome. Methods: A retrospective analysis was made of a contemporaneously maintained database of all PT's (simultaneous pancreas kidney (SPK); pancreas after kidney (PAK) and pancreas transplant alone (PTA) performed in a single institution between the inception of the programme and the present (June 2001 to May 2011). Rates of graft thrombosis, bleeding and haematoma were assessed and their impact on outcome identified. All patients were given adequate heparin thromboprophylaxis intravenously post-operatively as per defined unit protocols (initially S/C heparin leading to increased thrombosis rates, then systemic heparinisation with concomitant risks of haemorrhage, with the current policy judicious use of body weight adjusted systemic heparin.) Primary endpoints used were patient and graft survival with post-operative complications (including biopsy proven rejection, intra-abdominal sepsis and re-operation) as secondary endpoints. Results: 230 PTs were performed over the study period (180 SPK's, 13 PTA's and 37 PAK's; 143 M, 87 F; median age 41 (range 15-67). Bleeding and haematoma occurred in SPKs (16, 9%), PTAs (3, 23%; p=0.09) and PAKs (2, 5%; p=0.30, Fisher's exact test), whilst graft thrombosis occurred in SPKs (17, 9%), PTAs (3, 23%; p=0.14) and PAKs (7, 19%; p=0.06). Graft loss at 30 days was significantly higher due to thrombosis than post-operative bleeding (60.5% vs 7.9%, p< 0.002, Z-ratio) such that 25/27 thrombosed PT grafts underwent transplant pancreatectomy. Patient survival was 92% at 1 year and 76% (censored; mean follow up 4.3 years) However, re-operation rates due to thrombosis and bleeding were similar (23% vs 24%, p=NS). Rates of intra-abdominal sepsis, wound infection and BPAR did not differ according to graft thrombosis or bleeding (p=NS). Conclusion: The development and improving success of whole organ pancreas programmes internationally is at least partially due to increased recognition of and attention to the importance of adequate thromboprophylaxis. Previous experiences coupled with justified reticence on the part of clinicians to expose patients to the risks of peri-operative bleeding have historically led to bias towards minimal anti-coagulation. However, this study has demonstrated that the risk of graft loss is significantly higher due to thrombosis than haemorrhage and that peri-operative thromboprophylaxis should be tailored to this end. Our practice has evolved towards systemic anti-coagulation with current thrombosis rates less than 5%.