Gray areas in vein disease: In this series of articles, we discuss the uncertain and the unsure. Eight thoughtful, knowledgeable, and confident vein specialists contemplate four venous disease areas: superficial disease; deep disease, reflux; deep disease, post-thrombotic; and acute DVT.

DEEP VEIN THROMBOSIS (DVT) causes post thrombotic syndrome (PTS) in up to 50% of its victims. The anatomic distribution plays a large role in who will and will not develop PTS. We know that the more central the obstruction (iliofemoral vs femoropopliteal vs tibial), the more likely and severe the PTS. There has long been a debate as to whether femoropopliteal (FP) DVT even needs to be treated, as it was believed that axialization of the femoral vein would minimize PTS. However, FP disease is not only more prevalent than iliofemoral (IF) DVT, but it can also lead to significant PTS, causing severe activity limitations and a decrease in quality of life.

The ATTRACT trial resulted in 44% of patients with femoropopliteal DVT, in both the pharmacochemical and conservative therapy arms, developing PTS at 24 months.¹ The ACCESS PTS trial demonstrated that the population with FP DVT alone had an initial mean Villalta score of 14.0 (bordering on severe PTS).²

Generally speaking, if the iliofemoral and popliteal veins are patent, and there are adequate collaterals to the profunda femoral vein (PFV), then there is a less likely risk of PTS. If the central veins are patent, and both the femoral and popliteal veins are diseased, or there are inadequate collaterals to the PFV to allow for decompression of the leg, then venous hypertension may develop, causing the sequelae of PTS. The same is seen, and is often worse, when both the FP and PFV are involved.

Until recently, there has been no literature or universally accepted technique for recanalizing the femoral or popliteal vein segments. There are, however, three techniques that have been described in efforts to improve PTS in those suffering from chronic veno-occlusive disease (CVOD). These include prolonged venoplasty (PTV), ACCESS PTS (ultrasound accelerated thrombolysis and PTV) and single session thrombolysis & angioplasty (SSTA). ^2–3

The techniques have similarities but also significant differences. Nonetheless, all recommend therapeutic anticoagulation when treating the involved segments. Most experts agree that LMWH should be started prior to the procedure, should continue for 14–30 days post procedure, then should transition to an appropriate oral agent. I have long preached to my patients the importance of the post procedural “ABC’s of DVT,” which stands for “activity, blood thinner & compression.”

Initial access should be obtained below the lowest level of venous occlusion to allow for creation of direct inline flow from the ankle back to the right atrium. This often means tibial access, utilizing US guided micropuncture access and placement of a 6 Fr sheath. Ascending venography is then performed, followed by CTO crossing of the affected segments using standard techniques. Once crossed, one of the following techniques can be employed.

Prolonged venoplasty consists of dilatation of the diseased segments to the expected size of the normal vein: usually 8–10 mm for the femoral, 6–8 mm for the popliteal, and 3–4 mm for the tibial veins. The balloon is inflated for 3–5 minutes across all the affected segments, followed by venography.

ACCESS PTS entails initial PTV, also to the expected size of the vein, followed by EKOS placement for ultrasound accelerated thrombolysis (USAT) for at least 12 hours. Infusion thrombolysis is performed, typically with r-tPA at 0.5 mg/hr and the coolant between 35–50 ml of normal saline solution (NSS) per hour. On day two, the patient is brought back to the Angio suite with adjunctive intervention as necessary. This usually involves additional, repeated PTV of any segment with residual disease. Prolonged venoplasty is often used here as well. Anecdotal experience as to the benefit of USAT has been to resolve intraprocedural thrombosis seen not infrequently despite anticoagulation. Additionally on day one, there have been chronic stenoses that are difficult to efface that are easily effaced on the day two.1 There have been in vitro reports of the ultrasound waves softening the collagen cross-linkage, thus allowing for improved stretching of the vein on day two.

Single session thrombolysis and angioplasty also uses CTO crossing techniques, but here, the venoplasty is performed with the Chameleon balloon (Chameleon TM PTA balloon catheter, AV Medical Technologies Ltd, Israel). During inflation, concurrent infusion of r-tPA is performed through the balloon catheter. Eight milligrams of t-PA is dissolved in 25 ml of contrast and 25 ml of normal saline solution. The mixture of the thrombolytic with the contrast allows direct visualization of the distribution of t-PA into the diseased vessel while minimizing systemic circulation. Three milliliters of the mixture is slowly injected through the infusion port during each balloon inflation.

Although the literature and the outcome for femoropopliteal venous intervention is weak, the ACCESS PTS trial demonstrated that the initial FP DVT population with a mean Villalta score of 14.0 significantly improved their PTS by reducing it to 7.2 at 365 days. Furthermore at one year, VEINES QOL improved from 67.7 to 86.6, and SF-36 PCS improved from 40.6 to 46.4. Lastly, intervention has been shown to be long lasting, as the ACCESS PTS doppler venous patency rates at 365 days were 98.5%, 93.9%, 92.2%, and 98.5% in the common FV, proximal FV, distal FV, and popliteal vein respectively.²

References:

1. Vedantham S, et al. Pharmacomechanical catheter-directed thrombolysis for deep-vein N Engl J Med. 2017;377:2240–2252.
2. Garcia MJ et. al. Ultrasound-Accelerated Thrombolysis and Venoplasty for the Treatment of the Postthrombotic Syndrome: Results of the ACCESS PTS JAMA. February 2020 9(3):e013398 DOI: 10.1161/JAHA.119.013398.
3. Garcia R, et Single Session Venoplasty and Targeted Thrombolysis for Chronic Infrainguinal Venous Obstruction: A Novel Concept.Vein Magazine Spring/Summer 2018; 24-26.