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Catheter-directed thrombolysis reduces risk of post-thrombotic syndrome in patients with DVT in the lower limbs, CAVENT study finds

Researchers from Norway have found that additional treatment with catheter-directed
thrombolysis (CDT), when compared to standard treatment of oral anticoagulation
therapy and elastic compression stockings, reduces the risk of post-thrombotic
syndrome (PTS) in patients who suffer from deep-vein thrombosis (DVT) in their lower

To reduce the risk of developing post-thrombotic syndrome, additional therapy is needed via
catheter-directed thrombolysis, a minimally invasive procedure that uses x-ray imaging to
administer medication to help dissolve clots through a catheter placed in the vein. This
procedure has become standard of care for the prevention of post-thrombotic syndrome in
some treatment centres, despite a lack of randomised, controlled trials demonstrating its

efficacy and safety, as well as several drawbacks including its high expense, association with
life-threatening bleeding, and tendency to convert DVT (typically an outpatient condition) to
an in-patient disease requiring hospitalisation. To evaluate whether additional treatment of
deep-vein thrombosis with CDT with alteplase reduces post-thrombotic syndrome
development following acute iliofemoral DVT (occurring in the upper thigh and/or pelvic
area), Enden et al embarked on the CAVENT (Catheter-directed venous thrombolysis in acute
iliofemoral vein thrombosis) study, a large, four-year, multicentre, randomised controlled
trial. The study was presented by Tone Ronnaug Enden, Oslo University Hospital, Norway,
on 13 December at a late breaking trials session at the 53th American Society of Hematology
meeting in San Diego, USA In this trial, 209 patients between the ages of 18 and 75 with a
first-time acute iliofemoral DVT, with symptoms present for up to 21 days, were randomised
into two treatment arms: Treatment arm A (the CDT-treated arm) had 101 patients and arm B
(control arm treated with oral anticoagulant and ECS) had 108 patients. The primary endpoint
of the trial was the frequency of post-thrombotic syndrome after 24 months of follow-up. Of
the 90 CDT-treated patients and 99 control patients who had data available for analysis,
41.1% of patients treated with CDT presented symptoms of post-thrombotic syndrome
compared to 55.6% of control patients. The difference in post-thrombotic syndrome incidence
corresponds to an absolute risk reduction of 14.4% in patients treated with CDT. Twenty
bleeding complications were reported, three classified as major and five considered clinically
relevant. None of the reported bleeding episodes caused serious complications, and there were
no pulmonary emboli, strokes, or deaths related to treatment with CDT. After six months of
follow-up, post-thrombotic syndrome developed in 36.9% of patients who no longer had a
clotted vein, as compared to 61.3% of patients who still experienced clotting. These outcomes
underscore the importance of recanalisation for preventing post-thrombotic syndrome and
ensuring positive outcomes in patients with deep vein thrombosis. “The results of our trial
show that additional treatment with CDT significantly reduces the risk of post-thrombotic
syndrome in patients with DVT, compared to standard treatment alone,” said Per Morten
Sandset, senior author and Head of Research, Clinic of Cancer, Surgery, and Transplantation,
Oslo University Hospital, Norway. “Although CDT is a promising treatment option for
patients with iliofemoral DVT, the therapy also increases the risk of bleeding, emphasising
the importance of patient selection and safety when performing CDT procedures. Our
findings suggest that CDT should be considered in patients with upper thigh or pelvic DVT.”