OC 74.2 - Ultrasound-accelerated catheter-directed thrombolysis, effects on patency and reflux in relation to post-thrombotic syndrome: a subanalysis of the CAVA trial.

Background: Trials investigating adjunctive catheter-directed thrombolysis (CDT) have shown conflicting results in preventing the post-thrombotic syndrome (PTS), despite restored patency.

Aims: This subanalysis of the CAVA trial, investigated the effect of CDT on patency and reflux and its role and relevance in PTS development.

Methods: This multicentre, randomised, single-blind trial, enrolled patients aged 18-85 years, with a first iliofemoral DVT and symptom duration ≤14 days. Patency and reflux were assessed by extended duplex ultrasound (DUS) at 12 months (T12) and long-term (LT) follow-up (median 39.5 (24.0-63.0) months). The Villalta score was used to diagnose PTS.

Results: We included 152 patients with DUS at T12 or LT.(Table 1) CDT significantly improved complete vein patency at T12 (60.3% CDT vs. 25.9% standard treatment (ST), p=0.002) and LT (45.2% CDT vs. 11.9% ST, p< 0.001). Popliteal reflux was significantly reduced in the CDT group at LT (22.6% CDT vs. 44.8% ST, p=0.010). Only in the standard group lack of Iliac vein patency at T12 was associated with a higher risk of PTS (OR 10.84 (1.93-60.78); p=0.007). In the CDT group popliteal reflux at T12 was associated with moderate-severe PTS at T12 (OR 4.88 (1.10-21.57); p=0.041) and LT (OR 5.83 (1.44-23.63); p=0009). In the multivariate logistic regression model, lack of iliac patency (OR 3.00; 95% 1.19-7.56; p=0.020) and popliteal reflux (OR 3.11; 95% CI 1.21-8.02; p=0.019), were significantly and independently associated with moderate-severe-PTS. In the subgroup of patients with moderate-severe PTS the combined presence of reflux and lack of patency was associated with a significantly increased risk of PTS.(Table 2)

Conclusion(s): CDT significantly improved patency and reduced popliteal reflux. Both iliac patency and popliteal reflux are independently associated with moderate-severe PTS and play a synergistic role in the pathophysiology of PTS. However, a proportion of moderate-severe PTS cases lack evident underlying causes suggesting heterogeneity in PTS origin.