CHAPTER 107: Endovascular Pancreas Thrombectomy as a Salvage Approach After Transplant

INTRODUCTION

Vascular complications, usually thrombotic, account for the majority of pancreas graft loss during early transplant period.^1,2 Both arterial and venous thrombosis can occur, but the venous occlusion predominates, with an estimated overall reported rate between 6% and 33%.^2–5

Early thrombosis (< 2 weeks) is usually multifactorial, and although the factors considered to be most relevant are donor and recipient characteristics, as well as surgical/technical factors and the type of preservation solution used has been recently reported to be a concomitant or additional risk factor.⁶ Beyond 2 weeks, pancreas graft thrombosis is nearly always immunologically mediated, although pancreatitis also has been described as a possible cause of late vascular thrombosis.¹

Worldwide, almost all centers performing pancreatic transplantation use anticoagulation protocols for primary thromboprophylaxis. In spite of its use, early diagnosis of a vascular event is mandatory to be able to save the graft. For that reason, and although frequent blood glucose level monitoring are required, a protocolized visualization of the vascular flow by Doppler ultrasound (US) during the first 3–5 days posttransplantation has been accepted for most programs as a complementary diagnostic tool. Nevertheless, if a patient presents variations in glycemic control or experiences abdominal symptoms such as discomfort, pain, or fever, an extra US exam should be performed to rule out the presence of a thrombotic event.

When the US results are not conclusive, a contrast computed tomography (CT) scan should be performed (Figure 107-1).^5–7 The CT not only becomes a diagnostic tool but also will guide the therapeutic approach to be proposed. Hakeem A, et al.² classified the severity of the venous thrombotic event based on triple-phase CT scan as: Grade 0: no thrombosis; Grade 1: peripheral thrombosis; Grade 2: intermediate nonocclusive thrombosis; and Grade 3: central occlusive thrombosis.

Thrombosis can be seen in the body or the tail of the pancreas, and it can be secondary to a vascular kink near its isthmus; however, it usually occurs in the main portal vein of the graft or in the interposition graft, when it is used. When the early diagnosis is missed, the graft will need to be removed because thrombectomy will not restore functionality.

With early diagnosis, a salvage procedure can and should be attempted. For many years, surgery was seen as the only technique available, although the procedure might increase the risk of other complications such as duodenal fistula^3,4 that indeed lead to the necessity for a transplantectomy. The endovascular thrombectomy appears to be a nonsurgical, less invasive procedure, although until recently only limited experience and short-term follow-up were reported.^8...