CaVenT study five-year outcome data show “continued and increased benefit” for catheter-directed thrombolysis


The as-yet unpublished, five-year outcome after catheter-directed thrombolysis for upper femoral and/or iliac vein thrombosis, as determined from the randomised, controlled trial, the CaVenT study, were presented at the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) meeting (26–30 September, Lisbon, Portugal).

Nils Einar Kløw, Oslo University Hospital, Oslo, Norway, reporting the results on behalf of the investigators, said: “Follow-up after 60 months showed a continued and increased benefit of catheter-directed thrombolysis [in reducing the incidence of post-thrombotic syndrome, after high proximal deep vein thrombosis] from two- to five-year follow-up, which underpins the importance of recanalisation of occluded veins.”

The investigators randomised patients with a first-time objectively verified deep vein thrombosis affecting the upper half of the femoral vein and/or the iliac vein and with symptoms up to 21 days to either receive conventional therapy, with anticoagulation and compression stockings alone or conventional therapy with an additional catheter-directed thrombolysis.

They then assessed post-thrombotic syndrome at the five-year follow-up period using the Villalta scale.

A total of 209 patients were randomised in the period between 2006 and 2009. The mean age of patients was 51.6 years (standard deviation [SD], 16.8 years), and 38% were women. The mean duration of symptoms was 6.5 days (SD, 16.8 days). Nearly 50% of patients had an involvement of the pelvic veins.

The investigators had 60-month follow-up data on clinical status for 176 patients (89 control patients who had conventional therapy and 87, who underwent catheter-directed thrombolysis). Thirty-seven patients recruited for additional catheter-directed thrombolysis developed post-thrombotic syndrome as compared with 63 in the control group (p<0.001), including four in the catheter-directed thrombolysis group and one in the control group with severe post-thrombotic syndrome. This corresponded to an absolute risk reduction of 28% and a number needed to treat of four.

“The CaVenT study is the first randomised controlled trial to evaluate clinically relevant outcomes of additional catheter-directed thrombolysis in patients with iliofemoral deep vein thrombosis. Catheter-directed thrombolysis reduced the frequency of post-thrombotic syndrome. The effect of catheter-directed thrombolysis on the prevention of post-thromotic syndrome was sustained and increased from two to five years,” Kløw said.

“Our results support ‘the open vein hypothesis’ for the prevention of post-thrombotic syndrome and underpin the importance of early recanalisation. The CavenT study, together with the ongoing ATTRACT and CAVA trials, will provide evidence for the utility of catheter-directed thrombolysis in the treatment of severe proximal deep vein thrombosis. These findings should be taken into account when guidelines are revised,” he further added.