IMPORTANCE Little information is available on the long-term clinical outcome of patients with
splanchnic vein thrombosis (SVT).
OBJECTIVE To assess the incidence rates of bleeding, thrombotic events, and mortality in a
large international cohort of patients with SVT.
DESIGN, SETTING, AND PARTICIPANTS A prospective cohort studywas conducted beginning
May 2, 2008, and completed January 30, 2014, at hospital-based centers specialized in the
management of thromboembolic disorders; a 2-year follow-up period was completed January
30, 2014, and data analysis was conducted from July 1, 2014, to February 28, 2015.
Participants included 604 consecutive patients with objectively diagnosed SVT; there were
no exclusion critieria. Information was gathered on baseline characteristics, risk factors, and
antithrombotic treatment. Clinical outcomes during the follow-up period were documented
and reviewed by a central adjudication committee.
MAIN OUTCOMES AND MEASURES Major bleeding, defined according to the International
Society on Thrombosis and Hemostasis; bleeding requiring hospitalization; thrombotic
events, including venous and arterial thrombosis; and all-cause mortality.
RESULTS Of the 604 patients (median age, 54 years; 62.6%males), 21 (3.5%) did not
complete follow-up. The most common risk factors for SVT were liver cirrhosis (167 of 600
patients [27.8%]) and solid cancer (136 of 600 [22.7%]); the most common sites of
thrombosis were the portal vein (465 of 604 [77.0%]) and the mesenteric veins (266 of 604
[44.0%]). Anticoagulation was administered to 465 patients in the entire cohort (77.0%)
with a mean duration of 13.9 months; 175 of the anticoagulant group (37.6%) received
parenteral treatment only, and 290 patients (62.4%) were receiving vitamin K antagonists.
The incidence rates (reported with 95%CIs) were 3.8 per 100 patient-years (2.7-5.2) for
major bleeding, 7.3 per 100 patient-years (5.8-9.3) for thrombotic events, and 10.3 per 100
patient-years (8.5-12.5) for all-cause mortality. During anticoagulant treatment, these rates
were 3.9 per 100 patient-years (2.6-6.0) for major bleeding and 5.6 per 100 patient-years
(3.9-8.0) for thrombotic events. After treatment discontinuation, rates were 1.0 per 100
patient-years (0.3-4.2) and 10.5 per 100 patient-years (6.8-16.3), respectively. The highest
rates of major bleeding and thrombotic events during the whole study period were observed
in patients with cirrhosis (10.0 per 100 patient-years [6.6-15.1] and 11.3 per 100 patient-years
[7.7-16.8], respectively); the lowest rates were in patients with SVT secondary to transient risk
factors (0.5 per 100 patient-years [0.1-3.7] and 3.2 per 100 patient-years [1.4-7.0],
CONCLUSIONS AND RELEVANCE Most patients with SVT have a substantial long-term risk of
thrombotic events. In patients with cirrhosis, this risk must be balanced against a similarly
high risk of major bleeding. Anticoagulant treatment appears to be safe and effective in most
patients with SVT
- Splanchnic venous thrombosis