Residual vein thrombosis after a complete course of anticoagulation following unprovoked venous thromboembolism is not associated with recurrent vein thrombosis or other clinically important events, new data from the APSIRE study has shown.

Dr Timothy Brighton, a haematologist at Prince of Wales Hospital in Sydney and a principal investigator in the study, said previous research had suggested residual vein thrombosis (RVT) on ultrasound posed a continuing risk for recurrent thrombosis, other vascular events and mortality.

ASPIRE randomised 822 patients who had completed 6 to 24 months of anticoagulant therapy after a first unprovoked deep vein thrombosis or pulmonary embolism to low-dose aspirin or placebo for up to 4 years.

Dr Brighton’s group were able to review 412 of the 583 patients with DVT, of whom 265 (64%) had RVT.

There were a total of 72 first recurrent VTE events in these assessable patients. The rate of recurrence was 22% in those without RVT compared to only 15% in those with RVT.

“There was no association between the presence of RVT and the time to first recurrent VTE, when adjusted for study treatment,” Dr Brighton said.

“There was also no association between RVT and major vascular events or net clinical benefit after adjustment for treatment.”