Pathologic characteristics of human venous in-stent stenosis and stent occlusion

The Safety and Efficacy of ZelanteDVT™ Catheter Rheolytic Thrombectomy in the Treatment of Patients with Iliac Vein Stent Thrombosis

BACKGROUND

To examine the safety and efficacy of ZelanteDVT™ catheter rheolytic thrombectomy in the treatment of patients with iliac vein stent thrombosis.

METHODS

A retrospective analysis method was conducted by means of collecting the data of 32 patients who had completed the treatment of iliac vein stent thrombosis with ZelanteDVT catheter rheolytic thrombectomy from March 2019 to March 2023. Data on clinical characteristics, technical success, clinical success, complications, and early follow-up were analyzed.

RESULTS

The technical success rates were 100%, intraoperatively, in which 22 cases were improved to thrombus clearance Grade II (50-90%), 10 were Grade III (>90%). There were 21 cases treated with subsequent catheter-directed thrombolysis, and the average urokinase administration of (120.90 ± 29.63)∗10ˆ4 units. The clinical success rates were 100% and the swelling of the affected limbs were significantly improved, a significant difference in the pre/postoperative between-thigh circumference difference [(5.16 ± 1.08) vs. (1.75 ± 0.84), P < 0.000]. The pre/postoperative Venous Clinical Severity Score was [(12.94 ± 1.70) vs. (7.44 ± 1.31), P < 0.000]. No serious complications occurred during the perioperative period. The postoperative and 12-month stent patency rate was 100.00% (32/32) and 71.88% (23/32), respectively.

CONCLUSIONS

The ZelanteDVT catheter rheolytic thrombectomy seems to have a promising application prospect for the treatment of patients with iliac vein stent thrombosis.

The impact of stent protrusion into the inferior vena cava or jailing of the contralateral iliac vein on the incidence of contralateral deep vein thrombosis following venous stenting

OBJECTIVE

Iliac vein stenting is the standard of care for patients with pelvic venous disorders secondary to symptomatic iliac vein outflow obstruction. Venous stents are often extended proximally into the inferior vena cava (IVC) which may result in partial or complete coverage of the contralateral iliac vein. The purpose of this investigation is to determine if extension of iliac vein stents into the IVC results in increased risk of contralateral deep venous thrombosis (DVT).

METHODS

We retrospectively reviewed prospectively collected data from 409 patients who underwent iliac vein stenting at the Center for Vascular Medicine (CVM) from 2019 to 2020. Stent type, covered territories, initial and follow-up consults, ultrasound and operative reports were reviewed to assess for incidence of post-implantation DVT. Patients were stratified into three groups: Iliac vein stents which protruded into the IVC, stents that completely covered the orifice of the contralateral iliac vein and those with no stent protrusion into the IVC.

RESULTS

Out of 409 patients, the average age was 53.96 ± 13.40 years with 94 males and 315 females. All stents placed were Venovo stents and all iliac vein lesions were non-thrombotic stenoses. The average follow-up period was 14.35 ± 10.09 months. The most common territories stented were the IVC-LCIV-LEIV (n = , 74%) and the IVC-RCIV-REIV (n = , 26%). Stent protrusion and distance into the IVC in millimeters (mm) was the following: Partial protrusion (n = 314, 77%, 27.6 ± 19.1), jailing of the contralateral iliac vein (n = 78, 19%, 45.9 ± 18.6), no protrusion (n = 16, 4%). The overall DVT rate post-implantation was 0.49% (n = 2). No DVTs ipsilateral to the index stent were identified and both DVTs were contralateral DVTs. A hypercoaguable disorder was reported in 6 patients (1.5%). There were no significant differences in prevalence of contralateral DVT between the three groups. (p = .35).

CONCLUSION

The rate of contralateral DVTs post iliac vein stenting with Nitonol based stents is extremely low. Partial or complete coverage of the contralateral iliac vein via stenting does not result in an increased incidence of contralateral DVT in the short-term. Longer follow up is needed to determine if contralateral DVTs occur after long-term implantation.

RevCore thrombectomy system for treatment of chronic left external and common iliac vein stent occlusion

In recent years, deep venous stenting has increasingly become a treatment strategy for post-thrombotic syndrome. Stent thrombosis can occur, resulting in symptom recurrence despite medical therapy, and there are few options available for durable stent patency restoration. We present a case of a 50-year-old male with prior iliocaval reconstruction that experienced recurrent left lower extremity swelling secondary to occlusion of left external iliac and common iliac vein stents during follow-up. Mechanical thrombectomy with the RevCore System and angioplasty was performed. One month later, the patient demonstrated widely patent bilateral iliac vein stents and complete symptomatic resolution. The RevCore System is a feasible alternative for treatment of chronic in-stent thrombosis.

Endovascular mechanical thrombectomy of iliofemoral venous stent occlusion with the novel RevCore thrombectomy system: case reports and literature review

Venous in-stent restenosis is not completely understood, and the currently available treatment is usually unsatisfactory. We describe the cases of two patients treated with the RevCore thrombectomy system (Inari Medical), designed for venous in-stent thrombosis. Case 1 involves a 62-year-old woman with post-thrombotic syndrome from iliac vein stent placement 15 years earlier. Case 2 describes a 30-year-old woman with post-thrombotic syndrome from recurrent iliac vein stent occlusion, despite therapeutic anticoagulation. Both patients had previous recanalization attempts at outside facilities that were unsuccessful. The RevCore system was safe and feasible in these initial cases, and more studies are warranted.

Histological Features of In-Stent Restenosis after Iliac Vein Thrombus Removal and Stent Placement in a Goat Model

PURPOSE

To establish an animal model for in-stent restenosis (ISR) after postthrombotic iliac vein stent placement and characterize histopathological changes in tissue within the stented vein.

MATERIALS AND METHODS

Iliac vein thrombosis was induced using balloon occlusion and thrombin injection in 8 male Boer goats. Mechanical thrombectomy and iliac vein stent placement were performed 3 days after thrombosis induction. Restenosis was evaluated by venography and optical coherence tomography (OCT) at 1 and 8 weeks after stent placement, and stent specimens were taken for pathological examination after the animals were euthanized.

RESULTS

Thrombosis induction was successful in all 8 goats, with >80% iliac vein occlusion. After thrombus removal, OCT revealed considerable venous intimal thickening and a small number of mural thrombi. Neointimal hyperplasia with thrombus formation was observed in all goats 1 week after stent implantation; the degree of ISR was 15%-33%. At 8 weeks, the degree of ISR was 21%-32% in 3 goats, and stent occlusion was observed in 1 goat. At 1 week, the neointima predominantly consisted of fresh thrombi. At 8 weeks, proliferplastic fibrotic tissue and smooth muscle cells (SMCs) were predominant, and the stent surfaces were endothelialized in 2 of 3 goats and partially endothelialized in 1 goat.

CONCLUSIONS

In the goat model, postthrombotic neointimal hyperplasia in the venous stent may result from time-dependent thrombus formation and organization, accompanied by migration and proliferation of SMCs, causing ISR. These results provide a basis to further explore the mechanism of venous ISR and promote the development of venous stents that reduce neointimal hyperplasia.

RETRACTED: Australian and New Zealand Society for Vascular Surgery clinical practice guidelines on venous outflow Obstruction of the femoral-iliocaval veins

BACKGROUND

The overall goal of this report is to provide a high-level, practical approach to managing venous outflow obstruction (VOO) in Australia and New Zealand.

METHODS

A group of vascular surgeons from the Australian and New Zealand Society for Vascular Surgery with specific interest, training, and experience in the management of VOO were surveyed to assess current local practice. The results were analyzed and areas of disagreement identified. Following this, the group performed a literature review of consensus guidelines published by leading international organizations focused on the management of chronic venous disease, namely the Society for Vascular Surgery, American Venous Forum, European Society for Vascular Surgery, American Vein and Lymphatic Society, Cardiovascular and Interventional Radiology Society of Europe, and American Heart Association. These guidelines were compared against the consensus statements obtained through the surveys to determine how they relate to Australian and New Zealand practice. In addition, selected key studies, reviews, and meta-analyses on venous stenting were discussed and added to the document. Finally, a selection of statements with >75% agreement was voted on, and barriers to the guideline's applicability were identified.

RESULTS

The document addresses two key areas: patient selection and technical aspects of venous stenting. Regarding patient selection, patients with a CEAP (Clinical-Etiologic-Anatomic-Physiologic) score of ≥3 or a venous clinical severity score for pain of ≥2, or both, and evidence of >50% stenosis on venography, computed tomography venography, magnetic resonance venography, and/or intravascular ultrasound should be considered for venous stenting (level of recommendation Ib) Patients undergoing thrombus removal for acute iliofemoral deep vein thrombosis, in whom a culprit stenotic lesion has been uncovered, should be considered for venous stenting (level of recommendation Ib). Patients with chronic pelvic pain, deep dyspareunia, postcoital pain affecting their quality of life, when other causes have been ruled out, should be considered for venous stenting (level of recommendation Ic). Asymptomatic patients should not be offered venous stenting (level of recommendation IIIc).

CONCLUSIONS

Patients with deep VOO have been underdiagnosed and undertreated for decades; however, in recent years, interest from physicians and industry has grown substantially. The advent of simpler and safer treatment options has revolutionized its management, but, unfortunately, formal training for venous disease has not grown at the same rate. Simplifying the technology and training required can result in inconsistent outcomes. These guidelines are aimed at developing standards of care and will serve as an educational platform for future developments.