Anticoagulant improves outcome of incidentally detected splanchnic vein thrombosis

Last Updated: 2016-06-02

By Will Boggs MD

NEW YORK (Reuters Health) - Incidentally detected splanchnic vein thrombosis is best treated with anticoagulation, just as in clinically suspected splanchnic vein thrombosis, according to an analysis of the International Registry on Splanchnic Vein Thrombosis (IRSVT).

The authors note that as many as 30% of patients with splanchnic vein thrombosis are diagnosed incidentally, and splanchnic vein thrombosis is detected in nearly 2% of abdominal computed tomography (CT) scans for other indications, especially in patients with cancer or liver cirrhosis. There is, however, almost no evidence about the clinical history and treatment of incidentally detected splanchnic vein thrombosis.

Dr. Nicoletta Riva, from the University of Insubria, Varese, Italy, and colleagues in the IRSVT study group used registry data to assess the risk factors for incidentally detected splanchnic vein thrombosis, the therapeutic strategies used in clinical practice, and the clinical outcomes of 597 patients (420 with clinically suspected splanchnic vein thrombosis and 177 with incidentally detected splanchnic vein thrombosis).

Patients with incidentally detected splanchnic vein thrombosis were significantly more likely to have underlying solid cancer or liver cirrhosis and less likely to have unprovoked or idiopathic splanchnic vein thrombosis or splanchnic vein thrombosis secondary to intra-abdominal inflammation or infection, according to the May 11 Lancet Haematology online report.

Just under two-thirds of patients with incidentally detected splanchnic vein thrombosis received anticoagulation therapy within the first month after diagnosis, and the remainder had not received any treatment at that point.

During a median follow-up of two years, the rate of thrombotic events (most of them recurrent splanchnic vein thrombosis) in patients with incidentally detected splanchnic vein thrombosis was 8.0 events per 100 patient-years, but the incidence was significantly lower with anticoagulation therapy (3.9 events per 100 patient-years) than without treatment (11.5 events per 100 patient-years) or after treatment discontinuation (11.9 events per 100 patient-years).

These thrombosis rates were similar to those encountered by patients with clinically detected splanchnic vein thrombosis.

The incidence of on-treatment bleeding was not significantly higher than the incidence of off-treatment bleeding.

The mortality rate among patients with incidentally detected splanchnic vein thrombosis was 9.5 deaths per 100 patient-years, and the rate did not differ between treated and untreated patients.

"Despite current guidelines suggesting not to treat incidentally detected splanchnic vein thrombosis, roughly two-thirds of such patients in our registry received anticoagulant therapy," the authors note.

"The high incidence of thrombotic events during follow-up, especially after treatment discontinuation or in untreated patients, and the efficacy and safety of anticoagulant therapy seen in this study suggest that anticoagulation should be considered for patients with incidentally detected splanchnic vein thrombosis," they say.

Dr. Paul R.J. Ames from Nottingham University Hospitals, Nottingham, UK, who coauthored an accompanying editorial, told Reuters Health by email that "as it stands, the registry offers more uncertainties than certainties. Once the registry has accrued more patients, split them in the main subgroups with adequate follow-up; then we can start reasoning."

Dr. Xingshun Qi from Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China, who recently reviewed the etiology, diagnosis, and treatment of splanchnic vein thrombosis, told Reuters Health by email, "I prefer to focus on the safety of anticoagulation treatment for incidentally detected splanchnic vein thrombosis in patients with liver cirrhosis, the major etiology of incidentally detected splanchnic vein thrombosis. The proportion of use of anticoagulation treatment is less frequent in patients with liver cirrhosis."

"Anticoagulation treatment is not associated with the occurrence of major bleeding in all included patients with incidentally detected splanchnic vein thrombosis," Dr. Qi said. "Notably, as the overall analysis is performed, the authors did not take account into liver cirrhosis. Thus, based on the study, the association between anticoagulation treatment and major bleeding remained unclear in cirrhotic patients with incidentally detected splanchnic vein thrombosis."

Dr. Maria T. DeSancho, from Weill-Cornell Medical College, New York, recently reviewed that institution's experience in patients with splanchnic vein thrombosis. She told Reuters Health by email, "Based on the findings from this registry, it appears to be prudent upon discussion with the patient to anticoagulate patients with incidental splanchnic vein thrombosis providing that there are no contraindications for anticoagulant therapy and that the patients are carefully monitored."

"The information obtained from this study may affect the recommendations offered by the American College of Chest Physicians regarding treatment of incidentally identified splanchnic vein thrombosis," Dr. DeSancho said.

Dr. Riva did not respond to a request for comments.

Pfizer Canada funded this research and had various relationships with three of the 12 authors.

SOURCE: http://bit.ly/1RQSgHM and http://bit.ly/1Ux6hii

Lancet Haematol 2016.