XVIII. Chronic deep venous obstruction treatment
XVIII. Chronic deep venous obstruction
treatment
Chronic venous obstruction endovascular treatment – lesson leaned
Michael Lichtenberg (Germany)
Over the last decade, the number of endovascular interventions has increased significantly, especially as concerns venous stenting, percutaneous venoplasty, and venous thrombus removal. In Germany, approximately two-thirds of such procedures are conducted in specialized venous centers. Such a center should complete more than 100 intravascular ultrasound scans per year, have a hybrid operation room, and have vascular surgeon interventionists. The price of a case with installing one stent is worth 3193 € or 4122 € if two or more stents are installed. In Germany, there are 6 high-volume specialized venous centers. Standards were created for recanalization of chronic venous outflow obstruction. Venous stenting is a safe and efficacious procedure with technical success rates between 94% and 96%. It is very important to consider the fact that it is essential to have different venous stents for different locations. For the inferior vena cava, stents should have a high radial force, for the iliac vein, the stent should have radial force plus flexibility, and for the common femoral vein, the stent should have flexibility, kink resistance, a low fracture rate, but there is no perfect venous stent for the entire venous system. As the last studies showed, stent patency is dependent on the area of the stent lumen, the flow rate, and the pressure gradient. An important factor affecting the success of stenting is the availability of intravascular ultrasound. Advantages of intravascular ultrasound include the possibility of obtaining dynamic measurements of the area and the degree of stenosis, analyzing morphological changes in the vein, dynamically evaluating compression, such as in the presence of the May-Thurner syndrome, not needing contrast, exactly determining the diameter and length of the required vein stent, exactly placing the vein stent, and analyzing the stent after implantation.
Do we need the dedicated venous stents for chronic venous obstruction treatment? Update of the current dedicated venous stents trials Steve Black (UK)
A meta-analysis conducted in 2016, showed that the patency rates of venous stenting were high (79% to 98%). Now there are 8 different systems: Ziver Vena (Cook), Vici (BSCI), Venovo (BD), Wallstent (BSCI), sinus-Venous (Optimed), sinus-Obliquus (Optimed), Abre (Medtronic), and Blueflow (Plus Medica). The FDA has only approved the Wallstent, Venonvo, and Vici. Today, all explorations in the area of venous stenting are very different in their design and cannot be compared straight away. The VIRTUS exploration data used the VICI venous stent in 170 patients, showing a primary patency of 84%, with a safety endpoint of 98.8%. The VERNACULAR study used the Venovo venous stent in 170 patients, showing a primary patency of 88.3%, with a safety endpoint of 93.5%. Stents can be made as a closed-cell, an open cell, a hybrid, or braided and they can be very different in terms of crush resistance, flexibility, radial strength, deployment, scaffolding, diameter, and length. In 2018, a randomized double-blind study compared medical treatment vs iliac vein stenting in chronic venous disease. At the 6-months follow-up, the mean visual analog scale pain score declined from a median of 8 to 2.5 in patients receiving stents and from 8 to 7 in patients receiving only medical treatment (P<0.001). The venous clinical severity score decreased from a median of 18.5 to 11 after stenting and from 15 to 14 with medical treatment (P<0.001). The 36-item short-form health survey (0-100) improved from a total median score of 53.9 to 85.0 with stenting and 48.3 to 59.8 after medical treatment (P<0.001). Stenting success depends on many factors, such as stent choice, placement errors, technical mistakes, level of inflow, and clotting system. Currently, more randomized control trials are needed for acute deep vein thrombosis, for chronic venous obstruction comparing different stents; in addition, more data is needed about new stents and the systems for stenting, and we need long-term patient outcome data to support their use.
Iliac vein confluence stenting and the contralateral iliac vein coverage consequences
Haraldur Bjarnason (US)
The frequency of contralateral deep vein thrombosis after iliac vein stenting is around 2.6%. The reason for such thromboses is that if, during stenting of the iliac confluence, the stent is installed so that it protrudes into the inferior vena cava, it then overrides the contralateral iliac vein, and, in some cases, the pseudointima is obstructed in the contralateral iliac vein. In a study conducted in 2018, the reasons for 111 rethromboses (10 of which were contralateral) after iliac vein stenting were studied, showing that if the stent is confined in the inferior vena cava, then the frequency of noncontralateral deep vein thrombosis increases. At the same time, if the stent is extended into the inferior vena cava, then the frequency of ipsilateral deep vein thrombosis is much lower, but the frequency of contralateral deep vein thrombosis increases. Therefore, placing overriding stents should be avoided, but current and old stent technology is imperfect; there is no way to avoid these complications and we look forward to future advancement of venous stenting technologies.
Interpretation of venous pathology with IVUS – VIDIO trial results and clinical practice
Antonios Gasparis (US)
The results from the VIDIO trial (Venography versus Intravascular ultrasound for Diagnosing and treating Iliofemoral vein Obstruction) were presented. The study enrolled 100 patients with venous disease of clinical class C4 to C6 and suspected iliofemoral vein obstruction; the study was conducted over 14 sites. During the study, the investigators imaged the inferior vena cava, common iliac vein, external iliac vein, and common femoral vein. Venograms were measured for vein diameter; intravascular ultrasound was used to provid diameter and area measurements. Multiplanar venograms included three views: anteroposterior and 30-degree right and left anterior oblique views. A 50% diameter stenosis by venography and a 50% cross-sectional area reduction by intravascular ultrasound were considered significant. Venography identified stenotic lesions in 51 of 100 patients, whereas intravascular ultrasound identified lesions in 81 of 100 patients. Compared with multiplanar venography, intravascular ultrasound was more sensitive for identifying significant venous obstruction, more accurate for determining the degree of stenosis or diameter, and the best guide for stent intervention. Compared with intravascularultrasound, the diameter reduction was, on average, 11% lower for venography (P<0.001). The intraclass correlation coefficient was 0.505 for vein diameter stenosis calculated with the two methods. Intravascular ultrasound identified significant lesions not detected with three-view venography in 26.3% of patients. Investigators revised the treatment plan in 57 of 100 cases after intravascular ultrasound, most often because of failure of venography to detect a significant lesion (41/57 [72%]). Intravascular ultrasound led to an increased number of stents in 13 of 57 subjects (23%) and the avoidance of an endovascular procedure in 3 of 57 subjects (5%). Overall, intravascular ultrasound changed the treatment plan in 57 patients; 54 patients had stents placed based on intravascular ultrasound detection of significant iliofemoral vein obstructive lesions not appreciated with venography, whereas 3 patients with significant lesions on venography had no stent placed based on intravascular ultrasound.
Stenting below the inguinal ligament
Michael Lichtenberg (Germany)
Michael Lichtenberg introduced a new system for stenting below the inguinal fold. When comparing patency of stents installed above the ligament with stents installed across the ligament, the rate of primary patency was 77% above the ligament (vs 50% across the ligament), primary-assisted patency was 100% above the ligament (vs 82% across the ligament), and secondary patency was 100% above the ligament (82% across the ligament), showing the advantage of stenting above the ligament. This result is due to a high frequency of stent fracture and stent compression at the ligament area. For the Vici venous stent, the rate of compression/fracture was 8% at 2 years. The common femoral vein places a lot of force on venous stents. Laser-cut nitinol stents seem to have shortcomings below the ligament (fracture, compression). If restenosis occurs, a second stent implantation becomes likely. Avoiding stent fractures means we need to think of different stent deigns. A woven nitinol stent design could be an option. To solve these problems, the blueflow Venous Stent was introduced. This stent is a hand-braided meshed stent made of two 0.22 mm electropolished nitinol wires. Using a raiding technique with two wires enabled a closed-loop design. Each wire loops back when it reaches the stent tip, thus creating 14 radial-force stable loops. Two wires are welded together at two points in the center of the stent. The welds are only 5-mm long and placed inside of the mash to avoid any vessel contact.
The intermediate results of the postmarket clinical follow-up, retrospective and prospective, observational study on the patency rates and clinical outcomes for iliofemoral residual thrombosis, obstruction, or stenosis after implantation blueflow Venous Stent implantation were presented. Observations were taken at 24 to 72 hours, after 3, 6, and 12 months, and then yearly for up to 5 years. The primary outcome for 20 patients after 12 months was the same: primary patency after 12 months was 19 (95.2%), the primary sustained clinical success rate was 20 (100%), and there were no stent fractures.
Tips and tricks for getting the best IVUS, stent apposition and stent sizing
Stephen Black (UK)
The technical aspects of using intravascular ultrasound were presented. For the first step, the degree of stenosis should be measured (area stenosis [%] and diameter stenosis [%]),and then intravascular ultrasound should be used to help decide the landing zones. To perform this function better, it is necessary to use the cm marking on the intravascular ultrasound catheter to indicate the extent of stenting and use the intravascular ultrasound head for exact positioning. Next, intravascular ultrasound is used to determine the stent size; it is essential to stent from the centrum to the periphery and to start >5 mm central to the lesion. Another tip is to use intravascular ultrasound to identify the peripheral landing zone. The distal landing zone has priority over extent of overlap; for example, where a 9-cm stent will end if placed with a 5-cm overlap. In conclusion, intravascular ultrasound adds significant diagnostic value, reduces radiation, reduces contrast, is repeatable, improves sensitivity of diagnostic testing, and is an essential part of a complete venous service.
When and how to perform endophlebectomy?
Jan Kęsik (Poland)
Stenting distal to the common femoral vein has a higher risk of early failure due to low flow. A hybrid procedure (endophlebectomy+iliocaval stenting}arteriovenous fistulae [AVF]) improves flow into the stent from all major side branches and creates a single lumen-landing zone for the stent. The indication for a hybrid procedure appears if postthrombotic vein-wall fibrosis has a place to be and synechiae are present in at least the common femoral vein, deep femoral vein, and femoral vein. An ipsilateral ultrasound guided puncture of the mid-thigh femoral vein is performed first, sometimes with the contralateral femoral vein or right jugular vein. After gaining access, a small-caliber (5-Fr) sheath is positioned, and, following a multiplanar venography intravascular ultrasound investigation, there is the passage of the wire. Then, the surgical stage of the procedure (exposure of the femoral veins, endophlebectomy, and creation of an AVF with a side branch of a great saphenous vein) is performed. Depending on vessel diameter, the venotomy is closed primarily or with a venous patch. The last step is the stenting. For postoperative care, intermittent pneumatic compression is started after operation and continued during the hospital stay, low-molecular-weight heparin is started directly after the intervention, and warfarin is started the next day, aiming for an international normalized ratio of 3 to 4. Anticoagulation is continued for at least 6 months. Duplex ultrasound is performed 2 to 3 weeks, 6 to 8 weeks, and 5 to 6 months after surgery. If no stenosis is found in duplex ultrasound, the second hospital admission to close the AVF is performed 2 to 6 months after surgery. If a stenosis in the endophlebectomy segment is identified, a stent extension is performed before the AVF closing. Jan Kęsik presented results from de Wolf et al (Br J Surg. 2017;104:718-725), showing that, in 70 patients who underwent a hybrid procedure, 16 (23%) had a reocclusion, 32 (46%) had stenosis distal to stent, 2 (3%) had residual stent compression, and 0 had a stent fracture after 1 year. In a comparison of the initial techniques (n=17) with the present contemporary techniques (n=14), a significant improvement was observed for acute thrombosis (0 vs 5 [279]) and for reintervention for common femoral vein stenosis (0 vs 2 [12%]).
How to deal with the venous stent restenosis?
Antonios Gasparis (US)
Venous in-stent restenosis (ISR) is not the same pathological entity as arterial ISR. The basis of venous ISR is thrombus lining of the stent, which is transformed through inflammation into collagen and ISR. There are two different “modes” of venous stent ISR: (i) “soft” ISR lesion (fresh thrombus); and (ii) “hard” ISR lesion (organized thrombus). Soft ISR responds to percutaneous transluminal angioplasty, and, to treat hard ISR, it is possible to use high pressure percutaneous transluminal angioplasty, restenting, and a debulking procedure. Postthrombotic lesions have higher ISR rates over nonthrombotic iliac vein lesions due to long fibrotic lesions and longer stents, and stent extension into the common femoral vein. In addition, postthrombotic patients are more likely to be hypercoagulable and they are more likely to have compromised inflow. The likelihood of thrombus layering is increased due to untreated disease (poor inflow and outflow), undersizing of the stent, and a poor anticoagulation regimen. Preventing ISR is easier than treatment, and for this, it is desirable to use intravascular ultrasound for all steps of stenting, use large balloons pre-dilated to at least a nominal diameter of the stent, use appropriate stent sizes (inferior vena cava [16-18 mm], external iliac vein [12-14 mm], and common femoral vein [10- 12 mm]). It is very important to use an adequate anticoagulation (low-molecular-weight heparin twice daily provides predictable treatment, duration of anticoagulation of at least 3 months). Stent surveillance with duplex ultrasound must be done after 1 to 3 months and every 6 and 24 months. If ISR suspected based on symptoms, perform a venogram, look for reasons for the failure, and treat early lesions. If ISR appears, then use a laser atherectomy catheter to debulk the stent-associated organized material to improve the outcome.
What if you have chronic infrainguinal deep vein disease?
Stephen Elias (US)
The prevalence of femoropopliteal deep vein thrombosis in the population is high, with around 950 000 cases of venous thromboembolism per year in the US and 55% of which are femoropopliteal deep vein thrombosis and 30% to 40% of which are due to postthrombotic syndrome (which is around 150 000 to 200 000 annual interventions. Potential options for the management of femoropopliteal obstruction are venous bypass, venous stenting (iliac, nonfemoropopliteal), venous angioplasty, and open endovenectomy. In the ACCESS PTS trial, where balloon dilatation of the segments with occlusive deep vein thrombosis was used, and infusion for ≥12 hours with acoustic pulse thrombolysis using the EKOS system showed an improvement in the signs of postthrombotic syndrome in 35% of patients and a reduction in the Vilalta score in 67% of patients.
A retrospective study investigated the use of single-session femoropopliteal venoplasty (SSFPV) with local infusion of tissue plasminogen activator (tPA) using a novel percutaneous transluminal angioplasty balloon with an injection port. All procedures were performed in an office-based laboratory. SSFPV was attempted in 19 patients; 2 patients were classified as C4b and 17 patients were classified as C6. The average tPA dose was 5 mg, and balloon diameters ranged from 4 to10 mm. There were no periprocedural complications. Ulcer healing occurred in 11 of 17 patients (65%). Treatment of femoropopliteal obstruction with venoplasty and adjunctive acoustic pulse thrombolysis has been performed, requiring an intensive care unit hospital admission. SSFPV with local tPA infusion can be performed in an outpatient setting and may potentially reduce the signs and symptoms of postthrombotic syndrome. In comparison with ACCESS PTS, treatment with SSFPV takes only 1 to 2 hours and it is characterized by a lower bleeding risk and lower cost. Treatment of femoropopliteal obstruction with venoplasty and adjunctive acoustic pulse thrombolysis has been performed, requiring an intensive care unit hospital admission. SSFPV with local tPA infusion can be performed in an outpatient setting and potentially may reduce the signs and symptoms of postthrombotic syndrome. These findings may warrant large longitudinal studies to demonstrate the effects of SSFPV.
Iliac vein stenting – is the effort justified? An analysis of published data and single centre real-world register data
Tobias Hirsch (Germany)
The indication for venous stenting in patients classified as C3-C6 is caused by deep venous insufficiency or venous claudication. Three groups of patients can be distinguished: (i) nonthrombotic iliac vein lesions without postthrombotic syndrome; (ii) postthrombotic syndrome with inferior vena cava, common iliac vein, and/or external iliac vein; and (iii) group 2 plus femoral vein and bifurcation. At the moment, the expediency of stenting for the nonthrombotic iliac vein lesions (group 1) is not in doubt; however, for group 2 and 3, the benefit of stenting is clear only for patients in group 2. Unfortunately, the frequency of simple iliac vein thrombosis (group 2) is very rare (2% to 7%), so invasive treatment of chronic venous occlusion is only appropriate for a small number of patients. Even for iliac vein obstruction, secondary patency rates (according to a review of 16 studies 2007- 2014, 2647 limbs) were 66% to 99%, showing that invasive treatment of chronic iliac vein occlusion has a suboptimal patency rate. Iliac vein stenting can cause complications (bleeding, stent compression, stent stenosis, etc). Therefore, iliac vein stenting warrants meticulous patient selection.
Venous leg ulcer in the patient with the secondary chronic venous disease patients: ablate or stent and which one first?
Joseph Raffetto (US)
According to data from William Marston (J Vasc Surg. 2011;53:1303-1308), among patients classified as C5 and C6, 50% reported a medical history of deep vein thrombosis. Overall, 37% of imaging studies demonstrated iliocaval venous obstruction of at least 50% and 23% of patients had obstruction >80%. No limb with superficial venous reflux alone was found to have iliocaval venous obstruction >80%. According to Peter Neglén (J Vasc Surg. 2007;46(5):979-990), venous ulcers were healed in 58% of patients 5 years after iliocaval venous obstruction stenting. In this study, 99 limbs from 96 patients underwent percutaneous iliofemoral stenting combined with saphenous ablation; 40 limbs had an active ulcer. Seshadri Raju published results (J Vasc Surg Venous Lymphat Disord. 2013;1(2):165-172) on treatment of venous ulcers: 189 limbs classified as C6 were treated (30 with laser ablation, 89 with stenting, and 69 with the both methods). The long-term results were the same for every group and were between 75% and 80% for ulcer healing after 60 months. Therefore, the recommendation was that endovenous saphenous ablation should be the initial procedure of choice if reflux is present in a large saphenous vein (>5 mm). If there is no saphenous reflux, an intravascular ultrasound examination and stenting for stenosis is the procedure of choice. If the refluxing great saphenous vein is small (<5 mm), combined great saphenous vein ablation and iliac vein stenting should be considered.
