Deep venous stenting with the Blueflow venous stent (Plus Medica) offers favourable primary patency, and is associated with significant continued improvement of symptom severity in patients with obstructive chronic venous disease (CVD) out to 12 months. Michael Lichtenberg (Vascular Center Arnsberg, Klinikum Hochsauerland, Arnsberg, Germany) et al note this was the main finding of a recent observational, single-centre study published in Vasa: the European Journal of Vascular Medicine, however, the authors suggest that future prospective research on long-term stent patency is required.
In patients with thrombotic or non-thrombotic obstruction, CVD is common following anticoagulation. Post-thrombotic syndrome is a common complication of this, with approximately two-thirds of iliofemoral thrombosis cases presenting due to extrinsic compression of the left-sided iliac vein, known as May-Turner syndrome. In current practice with patients presenting iliofemoral deep vein thrombosis (DVT), anticoagulation does not resolve the occlusive thrombi or prevent post-thrombotic syndrome, despite 100 per 100,000 patients experiencing diagnosis. In light of this, Lichtenberg et al therefore aim to evaluate the effectiveness and safety of the Blueflow venous stent, for the treatment of venous outflow obstruction.
This observational, single-arm, single-centre study, set out to recruit adults (over the age of 18), with symptomatic, non-malignant, non-thrombotic chronic vein lesions (NIVL) or post-thrombotic venous obstruction (PTO) of the iliofemoral vein segment. These patients received Blueflow venous stent implantation, and it was noted that all patients received periprocedural and postinterventional anticoagulation. The authors also note that patients with venous obstruction proximally from the common iliac vein (CIV) and prior venous stent implantation were excluded from the study.
Lichtenberg and colleagues, report primary patency and clinical improvement as the effective outcomes of this evaluation. In this case, primary patency at 12 months was defined as the cumulative incidence of patients, with the absence of less than 50% diameter obstruction of the treated segment, and modulated venous flow without prior surgical or endovascular recanalisation. The authors also describe that clinical improvement of symptoms were reported using the revised venous clinical severity score (rVCSS) and the comprehensive classification system for CVD—CEAP (clinical findings, etiological factors, anatomical cause, pathological cause) clinical score. The study’s safety outcomes, were characterised as recurrent DVT, major bleeding events, clinically driven target vein revascularisation, and index limb major amputation or death.
The authors note that from the period of February 2018 to March 2019, a total of 67 patients with iliofemoral chronic venous outflow obstruction were recruited, consisting of 50.7% females, aged 46±18.1 years. A total of 21 (31.3%) patients presented with NIVL—of which the Blueflow venous stent was fitted in the common iliac vein with extension into the inferior vena cava. Of the patients with NIVL, the average age was 47.3±19.7 (p=0.43), consisting of 17 (81%) females (p=0.001). In addition, 37 (55.2%) of patients demonstrated PTO, consisting of 15 (40.5%) females, with the average age of 42.0±15.5 (p=0.43). The authors also highlight that six-month follow-up was completed in 33 (49.3%) patients, with 12-month follow-up completed across 34 (50.7%) patients.
Lichtenberg et al describe that a large majority of patients (76.1%) presented a history of previous venous thrombotic disease—of these patients, 97.3% illustrated PTO, compared to 57.1% of patients with NIVL (p<0.001). In respect to patient history, 21.9% were previous or current smokers, 2.4% had hypertension and 17.9% had a history of cancer. Following analysis, it is noted that the median rVCSS score was 8, with median CEAP at 3. In patients with PTO, CEAP class larger than five was more common in comparison to NVIL patients, at 26.5% vs. 4.8% (p=0.04) respectively.
At six-month follow-up, and 12-month follow-up, 91.7% and 79.8% of patients presented primary patency of the target segment, respectively. The authors highlight that the average survival time of patients did not differ significantly between both NIVL (357 days) and PTO (422 days) patients (p=0.14). Additionally, at 12-month follow-up, a total of 11 patients presented significant limb-based venous outflow obstruction larger than 50 percent—nine of these were receiving anticoagulation during this period. Symptomatic improvement held no association to thrombotic condition at both baseline or stent extension. Furthermore, the authors report that during follow-up, six vein re-interventions were performed, with no major target limb amputation or deaths recorded.
The authors mention several limitations to the study, such as the inability to quantify the effectiveness of the novel braided stent effectiveness due to having no comparator. The patient range of characteristics, such as clinical severity, anatomic extent and DVT duration are suggested to have potentially interacted with the treatment effect, however, this was not possible to determine without a control group and appropriate power. Lastly, the authors recommend that future prospective research on long-term stent patency, in addition to randomised controlled studies, are required to contribute further to evidence, and to specify the place of deep venous stenting in iliofemoral double vessel disease treatment.