A systematic review of routine post operative screening duplex ultrasound after thermal and non-thermal endovenous ablation

Abstract

Objective: The Society of Vascular Surgery and the American Venous Forum recommend duplex ultrasound (DUS) following endovenous ablation. However, this screening may not be cost-effective or clinically indicated. The most common abnormal finding, endovenous heat-induced thrombosis (EHIT level 1-2), represents extension of thrombus from the saphenous <50% across the femoral or popliteal vein, which is thought to have a benign course regardless of intervention. The likelihood of venous thromboembolism (VTE) after thermal and non-thermal ablations was explored to determine the utility of routine postoperative DUS.

Methods: This is an updated and expanded systematic review including data from randomized trials and large observational studies (≥150 patients) of thermal and non-thermal ablations, examining the incidence of VTE. Using PubMed and EMBASE, 4584 publications were screened from 2000 through 2020. After applying inclusion and exclusion criteria, 72 studies were included. Random effects DerSimonian-Laird method was conducted to obtain the pooled incidence. We calculated the number of tests needed to detect one VTE, and the cost was derived from Center for Medicare Services tables.

Results: A total of 31,663 patients were included. The pooled incidence of EHIT II-IV, deep venous thrombosis (DVT), and pulmonary embolism (PE) was 1.32% (95% confidence interval [CI], 0.75%-2.02%); DVT (excluding EHIT), 0.20% (95% CI, 0.0%-0.2%); EHIT (I-IV), 2.51% (95% CI, 1.54%-3.68%); and EHIT (II-IV), 1.00% (95% CI, 0.51%-1.61%). There was no mortality. There was a lower DVT rate in thermal vs non-thermal ablations (0.23% vs 0.43%; P = .02); however, for all VTE (EHIT I-IV + DVT + PE), thermal techniques had more thrombosis (2.5% vs 0.5%; P <.001). When clinical significance is defined as DVT + EHIT (II-IV), 175 studies are needed to identify one VTE, costing $21,813 per "significant VTE." Patients receiving pharmacological prophylaxis had less EHIT I-IV compared with those who did not (3.04% vs 1.63%; P < .001); those who received DUS during the first post-op week had three times higher EHIT incidence compared with those whose first DUS was >7 days postoperative (6.6% vs 2.4%; P < .001).

Conclusions: For thermal and non-thermal endovenous ablations, the incidence of VTE diagnosed with routine DUS is small and without clear clinical significance but caries a high cost. The Society of Vascular Surgery and the American Venous Forum recommendation to perform DUS within 72 hours is not justified by these data. We recommend a more targeted post-ablation scanning protocol including symptomatic patients and those at high risk.

Keywords: DUS; Duplex; EHIT; Endothermal heat induced; Thrombosis; Ultrasound; Vein ablation.