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Anticoagulation appears safe, effective in patients with splanchnic vein thrombosis
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Patients with splanchnic vein thrombosis have a substantial, long-term risk for other thrombotic events that can be further increased by underlying conditions, although this risk may be reduced with anticoagulation therapy, results in JAMA Internal Medicine show.
“Our data suggest that the risk of thrombotic events, mainly recurrent [splanchnic vein thrombosis] or venous thrombosis in other sites, is substantial and nearly doubles the risk of major bleeding events,” the researchers wrote. “In addition, case fatality rates of vascular thrombotic events more than doubled the case fatality rates of hemorrhage.”
For a prospective cohort study, Walter Ageno, MD, of the department of clinical and experimental medicine, University of Insubria, Italy, and an international team of researchers enrolled 604 patients (median age, 54 years; 62.6% men) with splanchnic vein thrombosis (SVT) from 31 centers specialized in managing thromboembolic disorders; patients had been objectively diagnosed within 6 months of study inclusion.
The researchers gathered patients’ baseline characteristics, risk factors and information on antithrombotic treatment.
The investigators mainly looked for major bleeding (as defined by the International Society on Thrombosis and Haemostasis), bleeding necessitating hospitalization and thrombotic events (venous and arterial thrombosis), as well as all-cause mortality.
Anticoagulation therapy was administered to 465 patients (77%) for an average of 13.9 months; 175 patients (37.6%) received parenteral treatment only — primarily low–molecular-weight heparin — and 290 patients (62.4%) received vitamin K antagonists. Patients were followed, with regular visits, for 2 years; 21 patients (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 patients; 22.7%). Thrombosis occurred most frequently in the portal vein (465 of 604 patients; 77%) and the mesenteric veins (266 of 604 patients; 44%).
The overall incidence rates for major bleeding and thrombotic events, per 100 patient-years, were 3.8 (95% CI, 2.7-5.2) and 7.3 (95% CI, 5.8-9.3), respectively. The all-cause mortality rate was 10.3 (95% CI, 8.5-12.5).
During anticoagulation therapy, the incidence rates for major bleeding and thrombotic events, per 100 patient-years, were 3.9 (95% CI, 2.6-6) and 5.6 (95% CI, 3.9-8), respectively, compared with 1 (95% CI, 0.3-4.2) and 10.5 (95% CI, 6.8-16.3), respectively, after treatment ended.
Patients with cirrhosis demonstrated the highest rates of major bleeding (10 per 100 patients-years; 95% CI, 6.6-15.1) and thrombotic events (11.3 per 100 patients-years; 95% CI, 7.7-16.8). Patients with SVT secondary to transient risk factors showed the lowest rates of major bleeding and thrombotic events (0.5 per 100 patients-years; 95% CI, 0.1-3.7 and 3.2 per 100 patients-years; 95% CI, 1.4-7, respectively).
Mortality was highest among patients with solid tumors (39.5 per 100 patient-years; 95% CI, 31.1-50.1) and the lowest among patients with myeloproliferative neoplasms (3.4 per 100 patient-years; 95% CI, 1.1-10.4).
“Observations from the present study may help clinicians to balance the benefits and risks of anticoagulation treatment in this setting and substantially support the safety and efficacy of anticoagulant therapy in most patients with SVT,” the researchers conclude.
In an accompanying editorial, Jack Ansell, MD, of the department of medicine, Hofstra North Shore-Long Island Jewish School of Medicine, Hempstead, New York, noted the report “holds importance” due to the “relatively uncommon” nature of SVT.
“There are virtually no prospective randomized data on the appropriate therapeutic interventions and outcomes, and most knowledge of this condition comes from retrospective case series, small prospective cohorts or case reports,” Ansell wrote.
The findings by Ageno and colleagues can assist clinicians in making treatment decisions for patients with SVT and assessing “the risks and benefits trade-off” involved in anticoagulation therapy.
“The use of antithrombotic therapy in any condition is guided by the balance of the benefit of the therapy against the risk of therapy-induced bleeding,” Ansell wrote. “Balancing these risks is tricky when dealing with SVT, and more so than when dealing with deep vein thrombosis or pulmonary embolism. The results of this registry strengthen the evidence that therapy may have more net benefit than previously thought.” – by Julia Ernst, MS
Disclosure: The researchers report no relevant financial disclosures.
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