A Referral Pathway for Treating Patients With Severe Venous Disease Using Mechanical Thrombectomy

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In the United States, DVT affects hundreds of thousands of patients each year.^1,2 Approximately 20% to 50% of patients with DVT develop postthrombotic syndrome, a debilitating condition that can involve formation of venous leg ulcers in severe cases.³ Most available therapies for venous disease, including standard of care anticoagulation and compression, do not target deep vein obstructions and often do not improve the disease process, which highlights the need for effective interventions. Recently reported results from a study of patients with persistent venous disease indicate that MT can remove and disrupt wall-adherent obstructions in deep veins and can promote healing.⁴ An overview of the study and details regarding the multidisciplinary collaboration that led to favorable patient outcomes are presented herein.

Study design and setting

The single-center, retrospective analysis included all patients with a CEAP score of C6 secondary to DVT who underwent  underwent MT using the ClotTriever System (Inari Medical).⁴ Patients were referred by a group of associated care providers specializing in severe venous disease. When necessary, the MT procedure included adjunctive venoplasty and stent placement.

The study adhered to principles of the Declaration of Helsinki. All data were deidentified prior to analysis; thus, formal institutional review board approval was waived. Informed consent was provided by all patients.

Data collection, postprocedural anticoagulation, and follow-up

Patient history and presentation, procedural and discharge characteristics, and follow-up assessments were collected. Assessed safety events included all-cause mortality, pulmonary embolism, bleeding, acute kidney injury, and vessel or valve damage.

After the procedure, patients remained on their preprocedural anticoagulation regimen. If adjunctive stent placement occurred, patients were maintained on dual antiplatelet agents with aspirin 81 mg daily and clopidogrel 75 mg daily for 3 months, after which they continued aspirin monotherapy 81 mg daily. Patients continued to be seen by the referring physician during the follow-up period. In addition to assessing disease severity at follow-up visits, duplex ultrasound was also performed to confirm venous flow and vessel patency.

Outcomes

Technical success was defined as the ability to cross the deep vein obstruction and introduce the thrombectomy catheter. Clinical success was marked by improvement of C6 disease.

Case example

A previously published article discussed 1 of the study cases—a 66-year-old male who had severe venous disease for decades and was referred for amputation.⁵ However, instead of proceeding with amputation, MT was used to remove proximal venous obstructions and reestablish brisk cephalad flow (Figure 1). A stent was placed in the iliac segments as an adjunct. Compared with baseline, the patient reported less pain at follow-up and demonstrated both decreased edema and improvement from C6 to C5 disease.

Key outcomes

As previously reported by Mouawad,⁴ 11 patients with severe venous disease in 14 limbs underwent MT using the study device. The mean age was 59.7 years ± 11.8 standard deviation, and there were 4 females (36.4%) and 7 males (63.6%). The median symptom duration was 11.0 months (IQR, 6.0–17.0 months).

On diagnostic imaging, all patients demonstrated lower extremity deep vein obstruction in either the iliofemoral or the femoropopliteal segment, or both. Despite C6 disease, 2 limbs (14.3%) presented only isolated femoropopliteal venous obstruction. Most limbs demonstrated more proximal venous fibrotic occlusion.

Technical success was achieved in all limbs (Figure 2). A median (IQR) of 5 (4–6) device passes were performed per limb, and MT successfully removed and interrupted deep vein obstructions in all procedures. Stents were placed in 10 limbs (71.4%). One limb underwent neither venoplasty nor stent placement. Cephalad flow and complete patency were restored in all vessels.

All treatments were single sessions, no lytic agents were used, and the patients were discharged home. One patient was admitted to the hospital after MT for reasons unrelated to the procedure. There were no adverse events.

Follow-up evaluations occurred at a mean of 12.8 weeks ± 10.5. Clinical success was achieved in 100% of cases, with 12 limbs (85.7%) exhibiting improvement of CEAP score from C6 to C5. All limbs demonstrated sustained venous flow and luminal gain.

The patients in the current analysis had severe deep venous disease for a median of almost 1 year prior to the study intervention, and several were considered for amputation. Amputation has been reported to occur in roughly 3% of patients within a few years of developing C6 venous disease.^6,7 Instead, the patients in the current report were treated using an MT procedure that showed clear improvement with no adverse events or procedure-related hospitalizations. For example, sustained patency at a mean follow-up of approximately 3 months was demonstrated in 100% of cases, which suggests that MT is highly effective for this patient population.

Although MT may be effective for addressing severe deep venous disease, a remaining obstacle is the absence of care pathways to identify and refer appropriate candidates to comprehensive venous operators who are trained in advanced MT modalities. In the 2023 study by Mouawad,⁴ information from which is summarized in the current report, partnering with an affiliated care network led to the referral and evaluation of patients with a prior DVT (Figure 3). The first health care contact for such patients is likely to be a local provider who specializes in venous disease. Based on history and available imaging, patients can be referred for MT, receive interventional treatment, and then receive continuing care from their local physician.

If future studies confirm that MT and forthcoming venous tools are safe and effective for patients with severe deep venous disease, referral pathways like the one proposed in the present report could help guide patients to successful interventional treatment when conservative management has been unsuccessful.

The limitations of the current study include the retrospective design, small sample size, and lack of comparator cohort. Patients were treated by 1 specialist at a single center; thus, results may not be generalizable. Additionally, follow-up visits were inconsistent and occurred only through the achievement, or near achievement, of CEAP C5 disease. Future studies are needed to evaluate whether improvements in venous disease are maintained.

Historically, severe deep venous disease has been exceptionally difficult to manage, with few meaningful therapeutic advances despite high disease prevalence. In the current study of treatment with MT, all patients with deep vein obstructions demonstrated restored venous flow and notable disease improvement within a few months. However, connecting patients who would benefit from this therapy to an interventionist remains a challenge. Collaboration between severe venous disease specialists and comprehensive venous operators may lead to improved outcomes in this patient population.

Author: Nicolas J. Mouawad, MD, MPH, MBA

Affiliation: McLaren Health System, Bay City, MI

Disclosure: Dr Mouawad is a paid consultant for Inari Medical.

Correspondence: Nicolas J. Mouawad, MD; McLaren Health System, 1900 Columbus Ave, South Tower, 4th Floor, Bay City, MI 48708; nicolas.mouawad@mclaren.org

Manuscript Accepted: February 20, 2024