Gastrointestinal Ischemia in Acute and Chronic Portal Vein Thrombosis

Thrombosis of the portal vein, in the absence of cirrhosis or malignancy, is a
rare clinical entity. Venous congestion resulting from a thrombotic obstruction
of the portal vein can potentially lead to gastrointestinal ischemia. Due to
the rarity of this disorder, no controlled studies have been performed and
therefore it is unknown what the true frequency is of gastrointestinal ischemia
in patients with portal vein thrombosis. The major risk associated with
gastrointestinal ischemia is development of intestinal infarction. Infarction
and subsequent necrosis of (part of) the gastrointestinal tract is a serious
complication with a high risk of morbidity and mortality. Furthermore,
long-standing ischemia of the gastrointestinal tract can lead to a number of
complaints such as post-prandial abdominal pain, decreased apetite and weight
loss. More insight into the prevalence and clinical presentation of
gastrointestinal ischemia in patients with portal vein thrombosis can
contribute to an improvement of the treatment and care of these patients.
Since many patients with PVT have portal hypertension, we cannot assume that
decreased mucosal saturation measurements are only attributed to the presence
and extent of the portal and mesentery vein thrombosis but also to the presence
of portal hypertension. This could be a possible confounding factor for the
mucosal saturation measurements.
To determine whether the mucosal saturation measurements in patients with PVT
are only affected by the presence of presence and extent of the portal and
mesentery vein thrombosis and not portal hypertension, a comparison in mucosal
saturation measurements is needed between patient with PVT and a control group
consisting of patients with liver cirrhosis and evident portal hypertension.
Portal hypertension is defined as: the presence of varices and/or splenomegaly
and/or ascites and/or hepatic hydrothorax and/or increased hepatic venous
pressure gradient (>12 mm Hg) AND in the absemce of an intrahepatic shunting
stent (i.e. TIPS).

To evaluate the prevalence of gastrointestinal ischemia in patients with acute
and chronic non-cirrhotic, non-malignant PVT.

A single-center cohort study conducted by the Department of Gastroenterology
and Hepatology of the Erasmus MC, University Medical Center Rotterdam. All
patients diagnosed with or referred to this center for evaluation of acute or
chronic non-cirrhotic, non-malignant PVT are asked to participate in the study.

Inclusion in this study does not result in additional risks for the
participants because almost all investigations will take place during scheduled
interventions. Visible light spectroscopy will take place during a regular
diagnostic gastroscopy and this test will lengthen the procedure by no more
than two minutes. Abdominal ultrasound is not associated with any risks for the
participant, due to additional visualisation of the main abdominal arteries for
this study the ultrasound may take a few minutes longer (10 minutes longer at
most). To perform a sugar absorption test, urine samples of the patient need to
be collected after ingestion of a sugar-containing drink for a period of five
hours. During this time period the patient will have to remain in the hospital.
Apart from the time-burden associated with this test, there are no risks
involved. As part of the study a single blood sample is drawn by venapuncture
from all patients. During every venapuncture there is a minimal risk of pain,
swelling or infection around the puncture-site.

Control group
Patients with liver cirrhosis admitted for screening for liver transplantation,
will undergo the standard work-up for screening. This work-up includes
radiological imaging by abdominal duplex ultrasound and CT scanning of the
liver and the liver vasculature and also an upper gastrointestinal endoscopy to
assess and grade gastro-esophageal varices. Therefore no additional diagnostic
procedures are needed to assess presence of thrombosis of the mesenterial
vasculature or to perform the mucosal saturation measurements. For these
patients, no additional blood samples need to be collected for determination of
cardiovascular risk factors, as this is already part of standard work-up for
screening for liver transplantation. Due to the highly unlikely chance of small
bowel dysfunction in these patients, the sugar absorption test will not be
performed.