Venous graft thrombosis in a case of pancreas transplantation

Clinical History

Pancreas transplantation three days before. Asymptomatic.

Imaging Findings

Three days after a combined kidney-pancreas transplantation with enteric-portal pancreatic drainage (figure 1), the patient underwent Doppler examination. The spectral analysis revealed the presence of low flow in the splenic vein and diastolic flow inversion in the splenic artery. All clinical and laboratory findings were normal. Thus the patient was referred for a multirow Computed Tomography (CT) examination of the transplanted organs. CT examination revealed regular patency of the arterial vessels of transplanted pancreas and partial thrombosis of the splenic and portal donor’s veins (figure 2a-e). Therefore higher doses of heparin were administered. The patient underwent a further CT examination after one week demonstrating a complete resolution of the thrombosis (figure 3a-c).

Discussion

Pancreas transplantation was first performed by Kelly et al in 1966 at the Minnesota University in Minneapolis. At present time the International Pancreas Transplant Registry (IPTR) reports more than 15000 cases of pancreas transplantation in the world.
Isolated pancreas transplantation is indicated in patients with degenerative complications of diabetes mellitus type I and preserved renal function, while, if chronic renal failure or severe proteinuria are present the combined kidney-pancreas transplantation is the most suitable therapeutic option.
For pancreas transplantation two main techniques are available: the systemic-bladder drainage and the enteric-portal drainage. These techniques differ in the exocrine secretion drainage and in the venous anastomoses which allows the release of insuline into recipient’s circulation.
In the systemic-bladder technique, exocrine pancreatic secretion drains into the bladder of the recipient, while the pancreatic venous system is connected with the iliac axis.
In the portal-enteric technique, exocrine pancreatic secretion drains through the donor’s duodenum into a small bowel loop, meanwhile the insuline is released into the superior mesenteric vein and, therefore, into the portal venous system. This method permits a more physiological endocrine secretion. In both techniques arterial inflow occurs by means of an anastomosis with the arterial iliac axis of the recipient.
In the transplanted patients variable complications can occur and one of the most frequent is thrombosis of the transplanted organ veins, which is also a common cause of graft loss. This complication has non specific, hazy and late clinical and laboratory signs, but often causes typical and early Doppler US alterations. Therefore this technique is fundamental to identify early venous thrombosis. The most important Doppler signs are: absent or reduced venous flow, absent or inverted arterial diastolic flow, poor intraparenchymal vascular signals and high intraparenchymal vascular resistances.
Single or multi-row CT is useful in these circumstances, because it allows imaging in arterial and venous phases and to perform high resolution multiplanar and three-dimensional reconstructions, improving the study of the transplanted organ, and its vessels and anastomosis. CT examination can assess the presence and precise extent of the venous thrombosis and can exclude arterial thrombosis, pancreatic infarction and other peripancreatic or abdominal complications.
In cases of partial venous thrombosis, heparin therapy can stop thrombus progression, determining total clot dissolution, whereas in cases of complete venous thrombosis, urgent organ removal is required.

Differential Diagnosis List

Final Diagnosis

Partial thrombosis of splenic and portal veins of transplanted pancreas.

URL:	https://www.eurorad.org/case/2624
DOI:	10.1594/EURORAD/CASE.2624
ISSN:	1563-4086