Long-term Clinical Outcomes of Splanchnic Vein Thrombosis
Authors: Walter Ageno, Nicoletta Riva, Sam Schulman, Jan Beyer-Westendorf, Soo Mee Bang, Marco Senzolo, Elvira Grandone, Samantha Pasca, Matteo Nicola Dario Di Minno, Rita Duce, Alessandra Malato, Rita Santoro, Daniela Poli, Peter Verhamme, Ida Martinelli, Pieter Kamphuisen, Doyeun Oh, Elbio D’Amico, Cecilia Becattini, Valerio De Stefano, Gianpaolo Vidili, Antonella Vaccarino, Barbara Nardo, Marcello Di Nisio, Francesco Dentali
Journal: JAMA Internal Medicine (2015)

IMPORTANCELittle 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 PARTICIPANTSA prospective cohort study was 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 MEASURESMajor 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. RESULTSOf 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],respectively). CONCLUSIONS AND RELEVANCEMost 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.