Study identifies key factors affecting catheter-directed thrombolysis for iliofemoral deep vein thrombosis

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A study from Denmark finds that the most important factors to predict long-term competent veins after catheter-directed thrombolysis are symptom duration of less than two weeks and use of the pulse spray technique.

The study was presented at the European Venous Forum (26–28 June, Paris, France) by Pia Foegh, Vascular Clinic, Gentofte Hospital and Rigshospitalet, Copenhagen, Denmark, on behalf of the investigators.

Foegh stated that many factors seem to influence the outcome of catheter-directed thrombolysis of deep thrombosis of the iliofemoral vein and explained that this study set out to identify the factors associated with long-term competent veins after catheter-directed thrombolysis.

The investigators analysed data from 1999 to 2013, obtained from nearly 200 patients (over 200) limbs with iliofemoral involvement who underwent thrombolysis. They noted that the median follow-up was five years. The researchers obtained information on gender, age, side that treatment was carried out, inferior vena cava (IVC) atresia, IVC thrombolysis, history of stenting, duration and type of lysis (infusion vs. pulse spray), duration of symptoms, and chronic lesions from the patient records. For the study, outcome was defined as competent vein (as a primary patent vein without signs of reflux on ultrasound). They tested the association initially in a univariate survival model (Kaplan-Meier with log-rank test) and subsequently on a multivariate Cox proportional hazard model.

The researchers found that univariate analyses revealed that gender, duration of lysis, stenting, duration of symptoms, type of  lysis (infusion vs. pulse spray) and chronic lesions were significantly associated with outcome whereas age, side, IVC atresia and IVC thrombosis were not. The Kaplan-Meier model showed that the estimated per cent of competent veins was 79% after seven years. On the other hand, the multivariate Cox proportional hazard model revealed that symptom duration >2 weeks, pulse spray technique and chronic lesions were the only factors significantly associated with outcome. This model also showed that stenting was more frequently reported in patients with a longer history of symptoms and this was not identified as a prognostic predictor.

 

Niels Baekgaard, Vascular Clinic, Gentofte Hospital and Rigshospitalet, Copenhagen, Denmark, the senior author on the paper, told Interventional News: “This study emphasises, for the first time, that the duration of symptoms prior to treatment has a great impact on the results after catheter-directed thrombolysis. This means that patients with more than two weeks of symptom duration will achieve inferior results with this treatment that are almost similar to anticoagulation and compression alone for this category of patients. The results of this study also show that physicians are able to rely on the accuracy of patient’s memories with regard to the duration of symptoms. Perhaps, in the future, some of the newer imaging modalities in combination with patient history, will be able to estimate the thrombus age even more accurately and strictly in order to determine the best course of treatment.”

 

The researchers concluded that the most important factors for predicting long-term competent veins after catheter-directed thrombolysis are symptom duration less than two weeks and use of the pulse spray technique. “This corresponds very well with the international definition of acute deep venous thrombosis (which is DVT less than two weeks),” Foegh told delegates. She also noted that patients with chronic lesions distally to the iliac compression area seem to have poorer outcomes, perhaps because of previous subclinical episodes of former deep venous thrombosis.

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