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A systematic review of venous stents for iliac and venacaval occlusive disease
A systematic review of venous stents for iliac and venacaval occlusive disease Zachary F. Williams, MD, and Ellen D. Dillavou, MD, Durham, NC
ABSTRACT Objective: Endovascular stenting of the deep venous system is increasingly used to treat stenotic and occluded veins. This article reviews the efficacy and safety of venous stenting for lower extremity occlusive disease. Methods: The Ovid portal was used to search the MEDLINE database for English-language randomized controlled trials and case series published between January 1, 2005, and December 31, 2018, involving venous stenting for lower extremity and inferior venacaval occlusive and compressive disease. Studies were eligible for inclusion if they contained at least 30 patients with at least 6 months of follow-up. Clinical outcomes, long-term patency, complications, and postoperative anticoagulation regimens were reviewed. Also included are nationally presented trial results of dedicated venous stents that may not have been formally published yet. Results: Relevant studies were too heterogeneous for a formal meta-analysis to be performed. We analyzed 3812 stented limbs from 23 published studies and two national presentations. Dedicated venous stents were used in 740 patients, and standard stents were used in 3072 patients. The overall major complication rate was <1%. Median symptomatic improvement and ulcer healing were seen in 79% and 71% of the standard stented limbs, respectively. For standard stents, the median primary, assisted primary, and secondary patency rates were 71%, 89%, and 91%, respectively, with a median study follow-up of 23.5 months. Dedicated venous stents had an overall primary patency of 78.8% at 12 months, with lower patency (73%) seen in post-thrombotic vs compressive (96%) disease. Conclusions: Whereas the quality of evidence remains weak, iliocaval venous stenting appears to be a safe and effective treatment of chronic venous disease. In early results, dedicated venous stents appear safe and demonstrate results that are as good as or better than those of historically used devices. (J Vasc Surg: Venous and Lym Dis 2019;-:1-9.) Keywords: Chronic venous disease; Post-thrombotic syndrome; Nonthrombotic iliac vein lesions; Stents
Chronic venous disease (CVD) of the lower extremities is typically associated with leg swelling, pain, skin discoloration, and ulceration. Causes of CVD include postthrombotic syndrome (PTS), nonthrombotic iliac vein lesions (NIVLs), venous reflux due to incompetent valves, and insufficient muscle pump function. Increased venous pressure results in increased capillary permeability, tissue edema, fibrosis, tissue hypoxia, and ulceration. PTS is the development of CVD due to prior deep venous thrombosis (DVT). Scarring from the DVT causes reflux due to valvular incompetence and chronic venous hypertension due to venous obstruction or stenosis. PTS is the most common long-term complication of DVT and is seen in 20% to 50% of patients who have had a prior DVT.1 Severe PTS is seen in only 5% to 10% of
From the Division of Vascular Surgery, Duke University Medical Center. Author conflict of interest: none. Correspondence: Ellen D. Dillavou, MD, Division of Vascular Surgery, Duke University Medical Center, 407 Crutchfield St, Durham, NC 27704 (e-mail: ellen. [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the Journal policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest. 2213-333X Copyright Ó 2019 by the Society for Vascular Surgery. Published by Elsevier Inc. https://doi.org/10.1016/j.jvsv.2019.08.015
patients and is most frequent in those who have had iliofemoral DVT.2,3 Compression of the left iliac vein between the right iliac artery and the vertebra, May-Thurner syndrome, is the most common cause of NIVLs. However, NIVL can be caused by several other anatomic variants and is less frequently seen in the right iliac vein and inferior vena cava (IVC). CVD symptoms are caused by venous hypertension from the outflow stenosis. NIVLs are often asymptomatic and should not be treated in asymptomatic patients.4 It is thought that these asymptomatic lesions can become symptomatic after secondary insults, such as trauma, infection, venous reflux, obesity, lymphedema, surgery, and vasoactive medications. NIVLs are a less common cause of CVD compared with PTS; however, the increased use of intravascular ultrasound (IVUS) has revealed NIVLs to be a more common cause of CVD than was once thought.5-7 The diagnosis of CVD can often be determined by a thorough history and physical examination. Other causes of leg swelling that should be ruled out are acute DVT, heart failure, renal failure, liver failure, medication side effects, and lymphedema. Venous duplex ultrasound is a noninvasive, essential tool for evaluating CVD. It provides information about reflux, occlusion, and stenosis of the leg veins. Disease of the iliac veins can often be inferred from alterations in flow characteristics of the femoral system and may be directly visualized, depending on body 1
2
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habitus, skill and experience of the technologist, and capabilities of the ultrasound machine. Venous plethysmography may also be used to evaluate for reflux in select patients.8 Pelvic and occasionally extremity computed tomography or magnetic resonance venography should be used in patients who have risk factors and clinical features of CVD if venous duplex ultrasound and plethysmography are nondiagnostic. If there is evidence of CVD on noninvasive imaging or if there is high clinical suspicion and treatment would be appropriate, catheter-based venography and IVUS with possible venoplasty and stenting should be used.9,10 Venography has only about 50% sensitivity in detecting iliac vein lesions, whereas IVUS provides a sensitivity of at least 80% and has other advantages over venography.11-13 IVUS is the preferred procedural tool during venous diagnosis and stent placement as it allows three-dimensional visualization of the compressed area as well as precise sizing and deployment. The objective of this systematic review is to provide a description of the risks and outcomes of venous stenting through analysis of larger published data series. This information can then be used as a background for evaluation of new technology, with initial trial data presented.
METHODS The Ovid portal was used to search the MEDLINE database for articles relating to venous stenting that were published in English between January 1, 2000, and December 31, 2018. All studies cataloged in MEDLINE were eligible for review. The date last searched was February 1, 2019. To structure the review, the Preferred Reporting Items for Systematic Reviews and MetaAnalyses guidelines were followed.14 Individual researchers and sponsoring manufacturers were contacted for early trial data on emerging venous stent technology, but only publicly presented or published data are included in this review. Because of the heterogeneous nature of the studies, a meta-analysis could not be performed. The relevant studies were on venous stenting for lower extremity chronic occlusive and compressive venous disease. As the majority of venous stenting literature centered on iliac and IVC occlusive and compressive disease rather than on femoral-popliteal disease, which is variably stented, the decision was made to include the iliac and IVC sites exclusively in an effort to decrease heterogeneity. The Ovid portal was searched using the keywords “venous stenting,” “venous and stents,” or “vein and stent” in combination with “iliac vein stenosis,” “iliac vein compression syndrome,” “nonthrombotic iliac vein lesions,” “iliofemoral occlusion,” “post-thrombotic syndrome,” or “chronic venous insufficiency,” with the limitations of English language and human subjects. This resulted in 164 studies. These studies along with their key reference lists were reviewed by the authors for inclusion. Studies were
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chosen for screening if the following criteria were met: full-length article could be procured, condition treated was chronic venous occlusion or nonthrombotic venous compression, >30 patients were described, and median follow-up was at least 6 months. Articles involving the treatment of acute DVT were excluded if the outcomes were not reported separately from the PTS or NIVL patients. All studies were reviewed by the authors. No primary authors were contacted to verify information on published work, although initial work on new technology was obtained from primary authors with the permission of the stent manufacturer. If two articles appeared to contain the same patient samples, the smaller sample size or shorter follow-up of the two articles was excluded. In total, 23 published studies were included. All eligible studies were reviewed regardless of funding source. The data from published studies were pooled and examined in an effort to elucidate overall patency, reintervention rates, and patterns of anticoagulation or antiplatelet therapy during or after the procedure and to look for differences between stent types. Two additional studies15,16 were included in this report on the basis of recent presentation of results using dedicated venous stents. Studies were divided into those using stents that were designed or Food and Drug Administration approved for other uses (standards stents) and those that were specifically designed for use in venous settings (dedicated stents). The majority of dedicated stent trials were performed in Europe as this technology has recently been approved for use in the United States.
RESULTS Following a review of the literature, 20 articles involving 3072 stented limbs using off-label stents (standard stents) were included in this analysis. Three published articles17-19 and two national presentations15,16 of dedicated venous stents were reviewed separately and described 740 patients. Of the 20 studies of standard stents, all but 2 studies20,21 were retrospective reviews. Of these 3072 interventions, 51% of the limbs were stented for PTS and 49% for NIVL (Table I). The majority of studies used the Wallstent (Boston Scientific, Marlborough, Mass), but the Protége (ev3, Plymouth, Minn), S.M.A.R.T. (Cordis, Warren, NJ), Luminexx (Bard/ Angiomed GmbH & Co, Karlsruhe, Germany), Zilver Vena (Cook Medical, Bloomington, Ind), AndraStent XL (BioAssist, Albuquerque, NM), Gianturco Z (Cook Medical), LifeStent (Bard, Tempe, Ariz), and Absolute Pro (Abbott Vascular, Santa Clara, Calif) stents were also used. Clinical outcomes were variably reported by one of the following scoring or quality of life systems: Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) classification,40 Venous Severity Score,41 Villalta score,42 and revised Venous Clinical Severity Score (rVCSS).43 Ulcer healing and patency rates were also reported. For standard stents, median symptom relief, defined as an
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Table I. Study characteristics: Standard stents Study
Study type
No. of limbs treated
No. of PTS cases
No. of NIVLs
Type of stents
Retrospective
982
464
518
Wallstent, nitinol stent (brand not stated)
Hartung,23 2009
Retrospective
89
30
59
Wallstent
Kölbel,24 2009
Retrospective
59
59
0
Wallstent
Lou,25 2009
Retrospective
73
34
39
Luminexx stent
Neglen,22 2007
26
Retrospective
167
167
0
Wallstent
Retrospective
34
34
0
Wallstent
Meng,28 2011
Retrospective
272
0
272
Kurklinsky,29 2012
Retrospective
91
91
0
Ye,30 2012
Retrospective
224
0
224
Friedrich de Wolf,31 2013
Retrospective
63
54
9
Blanch,32 2014
Retrospective
41
41
0
Wallstent, Zilver Vena
George,33 2014
Retrospective
44
31
13
Niti stent, Luminexx stent
Raju,
2009
Rosales,27 2010
Liu,20 2014
Not stated Wallstent, EverFlex, S.M.A.R.T., Luminexx Wallstent Wallstent, sinus-XL, Zilver Vena, AndraStent XL
Prospective
48
12
36
Wallstent
Raju,34 2014
Retrospective
217
163
54
Wallstent, Gianturco Z stent
Sang,35 2014
Retrospective
67
67
0
Wallstent, S.M.A.R.T, Luminexx
Sarici,21 2014
Prospective
59
59
0
Nitinol stent (brand not stated)
Ye,36 2014
Retrospective
118
118
0
Wallstent, LifeStent, EverFlex
Rollo,37 2017
Retrospective
42
42
0
Wallstent, Absolute Pro
Rizvi,38 2018
Retrospective
268
0
268
Ye,39 2018
Retrospective
114
114
0
3072
1580
1492
Total
Wallstent Wallstent, Luminexx
NIVLs, Nonthrombotic iliac vein lesions; PTS, post-thrombotic syndrome.
improvement in the clinical scoring system used, was 79%. Median rate of ulcer healing was 71% with a median follow-up of 23.5 months. Median primary patency, primary assisted patency, and secondary patency were 71%, 89%, and 91%, respectively, with a median followup of 23.5 months (Table II). Fifteen studies of standard stents had separated stent patency results on the basis of patient presentation of PTS vs NIVL lesions. In analysis of these studies as single entities, primary patency, primary assisted patency, and secondary patency in treating thrombotic or occlusive lesions averaged 64%, 79%, and 85% at an average of 33 months of total follow-up. Compressive (NIVL) lesions averaged 93% primary patency and 100% secondary patency at an average of 32 months. One study had patency details on both groups of patients.22 Thirteen studies discussed postthrombotic results20,21,24-27,29,32,33,35-37,39 and two discussed compressive results.30,38 Dedicated venous stents in smaller studies and with early results showed similar clinical results (Table III). In these trials, ulcer healing was not routinely measured, but significant decreases in symptom scores, most often rVCSS, were seen in all studies, with an average decrease of 3.1 points for those studies using rVCSS. Patency data were slightly higher than for the
standard stents with 78.8% primary patency at 12 months overall. Two recent pivotal U.S. trials compared patency data using historic controls at 72% 12-month primary patency and found that the new stents were noninferior to this metric.15,16 For dedicated venous stents, PTS patency was markedly lower (73%) than in patients treated for nonthrombotic compression (96%). Complications. No studies reported any perioperative mortality or pulmonary embolism. Rates of complications were low, with a mean and median rate of 3.0% and 3.4%, respectively, in the use of standard stents. Described complications (Table IV) included access site hematoma, bleeding, arterial injury, retained guidewire requiring open removal, iliac vein rupture requiring conversion to an open procedure, wound complications when concomitant hybrid procedures were preformed, heparin-induced thrombocytopenia, contralateral DVT during follow-up, ipsilateral stent thrombosis within 30 days of the procedure, and stent migration or fracture requiring reintervention. Reporting of complications was variable among the studies. Specifically, access site hematomas, early ipsilateral DVT or stent thrombosis, and contrast material
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Table II. Study outcomes: Standard stents Study
Symptom relief,a %
Ulcer healing, %
Primary patency, %
Primary assisted patency, %
Secondary patency, %
Median follow-up, months
Neglen22
62
58
67
89
93
23
Hartung23
97
100
83
89
93
38
Kölbel24
51
NSb
67
75
79
32
NS
NS
71
NS
NS
6 48
Lou25 26
Raju
79
56
32
58
66
Rosales27
94
57
67
76
91
33
Meng28
94
85
92
NS
NS
46
Kurklinsky29
60
NS
71
90
95
11
30
Ye
89
82
99
100
NS
48
Friedrich de Wolf31
83
NS
74
81
96
9
Blanch32
80
NS
74
87
89
21
George33
NS
60
94
97
NS
15
Liu20
76
71
93
NS
NS
12
69
NS
96
24 36
Raju34
NS
NS
35
Sang
88
100
71
NS
83
Sarici21
69
75
86
NS
90
6
Ye36
71
78
70
90
94
26
84
67
66
NS
75
15
Rollo37 38
Rizvi
67
NS
98
NS
100
24
Ye39
70
61
53
NS
80
22
Median
79
71
71
89
91
23.5
NS, Not stated. a Symptom relief is defined as improvement in pain or edema per the clinical scoring system used. b Not stated or no ulcer patients in the study.
Table III. Dedicated venous stent trials and results
Author
Stent name
Van Vuuren,19 2018
sinusVenous
Material
Study type
Open cell, laser cut, self-expanding nitinol
Single-center retrospective
No. of patients 200: 48 NIVL, 103 PTS, 49 hybrid
CEAP C5 or C6
12-month primary patency
QoL score change
10.5%
68% (92% NIVL, 71% PTS)
3 VCSS
Marston,15 2019
VICI
Self-expanding nitinol closed cell
Prospective multicenter single arm
200: 50 NIVL, 150 PTS
25.4%
84% (98.2% NIVL, 79.8% PTS)
4.4 VCSS
Black,17 2018
VICI
Self-expanding nitinol closed cell
Single-center retrospective
88 PTS
15%
59% PTS
6 Villalta
Lichtenberg,18 2019
VICI
Self-expanding nitinol closed cell
Single-center retrospective
82: 40 NIVL, 42 PTS
15%
94% (100% NIVL, 87% PTS)
3 VCSS
Venovo
Self-expanding nitinol open cell
Prospective multicenter single arm
170: 72 NIVL, 84 PTS
NA
88.3% (96.9% NIVL, 81.3% PTS)
1.7 VCSS
Dake,16 2018 All
740; 31% NIVL, 69% PTS
Average 78.8% (95.8% NIVL, 73.4% PTS)
CEAP, Clinical, Etiology, Anatomy, and Pathophysiology; NA, not applicable; NIVL, nonthrombotic iliac vein lesion; PTS, post-thrombotic syndrome; QoL, quality of life; VCSS, Venous Clinical Severity Score.
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Table IV. Complications: Standard stents Study Neglen22
Complications, No. (%)
Type (No.) of complications
26 (2.6)
Retroperitoneal bleed (1), femoral artery injury requiring open repair (1), femoral artery pseudoaneurysms (3), arteriovenous fistula (1), retained guidewire requiring open removal (1), early ipsilateral DVT/stent thrombosis (8), contralateral DVT (11)
Hartung23
8 (9.0)
Stent migration (2), superficial femoral artery injury treated with a covered stent (1), early ipsilateral DVT/stent thrombosis (2), hemothorax (1), access site hematoma (2)
Kölbel24
3 (5.1)
Retroperitoneal bleed (2), access site hematoma (1)
Lou25
0 (0)
None
13 (7.8)
Early ipsilateral DVT/stent thrombosis (10), contralateral DVT (3)
2 (5.9)
Early ipsilateral DVT/stent thrombosis (2)
26
Raju
Rosales27 28
Meng
Kurklinsky29
0 (0)
None
1 (1.1)
Early ipsilateral DVT/stent thrombosis (1)
Ye30
3 (1.3)
Stent migration (3)
Friedrich de Wolf31
7 (11.1)
Access site hematoma (5), common femoral artery injury (1), heparin-induced thrombocytopenia (1)
Blanch32
1 (2.4)
Femoral artery pseudoaneurysm (1)
George33
2 (4.5)
Access site hematoma (2)
7 (14.6)
Access site hematoma (4), stent migration (2), iliac vein rupture
Liu
20
Raju34
10 (4.6)
Stent migration (2), early ipsilateral DVT/stent thrombosis (8)
Sang
3 (4.5)
Early ipsilateral DVT/stent thrombosis (3)
Sarici21
0 (0)
Ye36
0 (0)
Rollo37
4 (9.5)
35
Rizvi38
0 (0)
Ye39
15 (13.2)
None None Bleeding requiring transfusion (2), early ipsilateral DVT/stent thrombosis (2) None Early ipsilateral DVT/stent thrombosis (15)
Dedicated venous stents Black17
2 (2)
Paralysis after epidural bleed (1), footdrop after stent placed into spinal foramen (1); both injuries permanent
Lichtenberg18
1 (1.2)
Access site hematoma (1)
Marston15
2 (1.2)
Superficial femoral artery injury treated with a covered stent (1), arteriovenous fistula formation (1)
24 (10.0)
Early ipsilateral DVT/stent thrombosis (3), major bleeding (2), stent migration (1), wound infection (11), seroma/lymphocele (6), contralateral DVT (1)
van Vuuren19,a
DVT, Deep venous thrombosis. a Study had large number of hybrid operations.
extravasation appeared to be variably reported by the included studies. When only major bleeding, arterial injury, and nerve damage were included, the rate of complications was 0.5% per limb treated. Complications recorded in trials of dedicated venous stents reflect the same trends as seen with standard stents. Additions to this list would be paralysis due to spinal epidural hematoma and nerve damage due to stent
placed into spinal foramen, both from the same study.17 The overall rate of complications was 8.3% for dedicated venous stents. Authors’ suggested techniques for the operative approach to venous stenting. Placement of a venous stent for the treatment of iliofemoral obstruction is typically performed by ultrasound-guided access of the
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Table V. Postintervention anticoagulation regimen Postprocedure anticoagulationa
Study 22
Neglen
Lifelong aspirin
23
Therapeutic anticoagulation for 6 months
Hartung Kölbel24
Therapeutic anticoagulation for 6 months
Lou25
Therapeutic anticoagulation for 1-6 months
Raju26
Therapeutic anticoagulation for 3-5 days followed by aspirin or prophylactically dosed fondaparinux for 4-6 weeks
Rosales27
Pneumatic sequential pumps; otherwise not stated
Meng28
Not stated
Kurklinsky29
Therapeutic anticoagulation for 2 months
Ye36
Clopidogrel for 6 months
Friedrich de Wolf31
Therapeutic anticoagulation for 6 months
George33
Therapeutic anticoagulation for 3 months followed by lifelong aspirin
Blanch32
Lifelong aspirin
20
Therapeutic anticoagulation for 6 months
Liu
Raju34
Therapeutic anticoagulation for 6 weeks followed by lifelong aspirin
Sarici21
Clopidogrel for 2 months followed by lifelong aspirin
Sang35
Therapeutic anticoagulation for 6 months
30
Therapeutic anticoagulation for 6 months
Rollo37
Aspirin and clopidogrel for 3 months followed by aspirin indefinitely
Ye
Black17 Lichtenberg18
Therapeutic anticoagulation for an “extended” amount of time Therapeutic anticoagulation for 6 months for NIVL and 12 months for PTS
Rizvi38
Clopidogrel for 3 months
van Vuuren19
Therapeutic anticoagulation for 6 months
Ye39
Therapeutic anticoagulation for 6 months
NIVL, Nonthrombotic iliac vein lesion; PTS, post-thrombotic syndrome. a Patients undergoing complex venous reconstructions and with known thrombophilias were continued on therapeutic anticoagulation postoperatively.
ipsilateral femoral vein at the level of the midthigh. Popliteal, profunda, posterior tibial, and internal jugular veins can also be accessed if needed because of anatomic constraints. An appropriately sized (often 10F) sheath is then inserted over the wire. Antegrade venography is used to identify the obstruction. The area of disease is crossed with a guidewire. The patient is heparinized. IVUS may then be used to determine the degree of stenosis and the diameter of the iliac vein, especially in NIVL, as compression is often difficult to appreciate on two-dimensional venography. In cases of chronic occlusive disease and recanalization, it may not be useful to have IVUS. If it is used, IVUS should be used throughout the procedure to ensure proper stent placement and correction of the pathologic process. Stenotic lesions are then predilated with an angioplasty balloon. A self-expanding stent is placed, covering all areas of >50% stenosis with extension into the IVC of about 1 cm if a Wallstent is used to treat compression at the iliocaval junction. Dedicated venous stents can be placed more accurately with less extension into the IVC. If there are additional lesions below the inguinal ligament, the stent should be extended distally, as crossing
the inguinal ligament does not appear to affect patency.44 Great care should be taken not to “jail” the profunda vein as this affects immediate leg swelling and long-term outcomes. Obtaining good outflow and inflow is vital for long-term stent patency. Iliac vein stents are typically oversized by 2 mm, sized by the normal-caliber vein above or below the obstruction. Common stent diameter sizes are 16 mm for the external iliac and femoral veins and 18 mm for the common iliac vein. Once they are in place, the stents are dilated to the size of the native vessel. Post-stenting patency is confirmed with IVUS or venography. Bilateral “kissing stents” can be placed in patients with bilateral common iliac lesions and severe symptoms in both legs, although this situation is relatively rare and so should not be a common occurrence in most practices. Unilateral stenting can result in resolution of mild symptoms in the contralateral leg through decreased cross-pelvis collateral flow in favor of in-line flow. When an iliac vein stent is placed in the setting of an indwelling contralateral stent protruding into the IVC, a fenestration technique may lead to less stent compression compared with staged kissing stent deployment. The wider struts of
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the Gianturco Z stent may allow easier fenestration compared with Wallstents alone.34 Chronic iliocaval occlusions can often be navigated with a directional catheter and a Glidewire (Terumo Interventional Systems, Somerset, NJ) or by specialized crossing catheter systems. Once re-entry into the vena cava is confirmed, the track can be dilated by a sheath and then with angioplasty. A slightly oversized stent should then be deployed. Hyperdilation may be required to compensate for residual stent compression in the setting of chronic iliocaval occlusions. Postoperative considerations. Postoperative anticoagulation recommendations vary considerably. Of the 23 reviewed studies, most regimens give therapeutic anticoagulation for 2 to 6 months, followed by aspirin indefinitely (Table V). Long-term therapeutic anticoagulation is typically given to patients with a known hypercoagulable state requiring lifelong anticoagulation and for patients who undergo complex iliocaval recanalization after total occlusion with a history of DVT. Because of the heterogeneity of the treatment plans and the inability to confidently assign varying disease states or treatment plans to an anticoagulation regimen, no conclusions were able to be drawn from these data. Postoperative stent surveillance is typically performed with duplex ultrasound at 6 weeks, 6 months, and then yearly intervals after stent placement. If symptoms return or duplex ultrasound findings indicate narrowing of >60%, consideration should be given to evaluation of the area with venography or IVUS. With a median primary patency rate of 71% to 78% seen in our review, a significant number of patients will need reintervention.
DISCUSSION Conservative management, consisting of exercise, elevation, compression therapy, and local wound care, is first-line treatment of CVD. If the patient’s symptoms are refractory to conservative management, percutaneous venoplasty and stenting of areas of >50% stenosis should be performed, although some have suggested increasing the threshold of intervention to >60% stenosis for nonthrombotic patients.45 In cases of combined iliac obstruction and infrainguinal reflux, treatment of the proximal lesion is recommended first.40,45 After treatment of the obstructive lesion, many patients will not need treatment of the concomitant reflux.46 Open venovenous bypasses are reserved for severely symptomatic but otherwise healthy and mobile patients who have failed to respond to endovascular therapy. Venous stenting remains an off-label use of standard stents, with the exception of new devices with a venous indication, specifically the Zilver Vena (Cook Medical), Venovo (Bard), sinus-Venous (OptiMed, Ettlingen, Germany), and VICI (Boston Scientific).
In this systematic review of the published literature on the off-label use of bare-metal stents (standard stents) to treat obstructive and nonobstructive venous lesions, we found an overall primary patency and secondary patency of 71% and 91% at nearly 24 months of median follow-up, with consistently higher patency in treatment of nonocclusive lesions. A median of 79% of patients had symptom relief, and 71% of patients with ulcer demonstrated healing. In early trial results of dedicated venous stents, there was an average of 79% primary patency at 12 months. Patients stented for nonobstructive (NIVL) lesions experienced a higher patency of 96% vs those stented for obstructive disease at 73%.
CONCLUSIONS As illustrated in this review, the quality of evidence supporting venous stenting of the lower extremity is low. Despite this, there is widespread use of venous stents to treat lower extremity PTS and NIVL. The existing studies are limited by lack of controls, selection bias, and publication bias. Despite these limitations, this review illustrates a benefit in ulcer healing and in pain and swelling after intervention as measured by quality of life metrics. Venous stenting appears to safe, with no deaths or pulmonary embolisms in any of the included studies. True rates of other complications are difficult to assess as there are no widely accepted reporting guidelines. The rate of complications with dedicated stents was higher than with standard stents, but this may reflect more patients in trial settings or prospective analysis, which favors detection and reporting of complications vs a retrospective review. Given the potential for benefit and low incidence of major complications, current practice guidelines recommend venous stenting for severe lower extremity PTS or venous stasis due to NIVL refractory to conservative management.45 Recently approved dedicated venous stents are currently under active research, some of which are included in this review. With promising preliminary results, venous stenting is likely to continue to be an area of active industry development. Additional high-quality research is needed in this field. The Chronic Venous Thrombosis: Relief with Adjunctive Catheter-Directed Therapy (C-TRACT) trial is a multicenter randomized controlled trial that will evaluate the use of endovascular intervention in patients with PTS. Once it is completed, this study will, it is hoped, provide additional insight into the safety and efficacy of venous stenting for obstructive CVD and how it compares with conservative management.
AUTHOR CONTRIBUTIONS Conception and design: ZW, ED Analysis and interpretation: ZW, ED Data collection: ZW, ED Writing the article: ZW, ED
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Critical revision of the article: ED Final approval of the article: ZW, ED Statistical analysis: Not applicable Obtained funding: Not applicable Overall responsibility: ED ZW and ED contributed equally to this article and share co-first authorship.
17.
18.
REFERENCES 1. Roumen-Klappe EM, den Heijer M, Janssen MC, van der Vleuten C, Thien T, Wollersheim H. The post-thrombotic syndrome: incidence and prognostic value of non-invasive venous examinations in a six-year follow-up study. Thromb Haemost 2005;94:825-30. 2. Baldwin MJ, Moore HM, Rudarakanchana N, Gohel M, Davis AH. Post-thrombotic syndrome: a clinical review. J Thromb Haemost 2013;11:795-805. 3. Kahn SR, Kearon C, Julian JA, Mackinnon B, Kovacs MJ, Wells P, et al. Predictors of the post-thrombotic syndrome during long-term treatment of proximal deep vein thrombosis. J Thromb Haemost 2005;3:718-23. 4. Negus D, Fletcher EW, Cockett FB, Thomas ML. Compression and band formation at the mouth of the left common iliac vein. Br J Surg 1968;55:369-74. 5. Raju S, Neglan P. High prevalence of nonthrombotic iliac vein lesions in chronic venous disease: a permissive role in pathogenicity. J Vasc Surg 2006;44:136-43. 6. Neglén P, Thrasher TL, Raju S. Venous outflow obstruction: an underestimated contributor to chronic venous disease. J Vasc Surg 2003;38:879-85. 7. Raju S. Best management options for chronic iliac vein stenosis and occlusion. J Vasc Surg 2013;57:1163-9. 8. Neglén P, Raju S. Detection of outflow obstruction in chronic venous insufficiency. J Vasc Surg 1993;17:583-9. 9. Gloviczki P, Comerota AJ, Dalsing MC, Eklof BG, Gillespie DL, Gloviczki M, et al. The care of patients with varicose veins and associated chronic venous diseases: clinical practice guidelines of the Society for Vascular Surgery and the American Venous Forum. J Vasc Surg 2011;53:2S-48S. 10. Wittens C, Davies AH, Bækgaard N, Broholm R, Cavezzi A, Chastanet S, et al. Editor’s choicedmanagement of chronic venous disease: clinical practice guidelines of the European Society for Vascular Surgery (ESVS). Eur J Vasc Endovasc Surg 2015;49:678-737. 11. Gagne PJ, Tahara RW, Fastabend CP, Dzieciuchowicz L, Marston W, Vedantham S, et al. Venography versus intravascular ultrasound for diagnosing and treating iliofemoral vein obstruction. J Vasc Surg Venous Lymphat Disord 2017;5:678-87. 12. Neglen P, Raju S. Intravascular ultrasound scan evaluation of the obstructed vein. J Vasc Surg 2002;35:694-700. 13. Satokawa H, Hoshino S, Iwaya F, Igari T, Midorikawa H, Ogawa T. Intravascular imaging methods for venous disorders. Int J Angiol 2000;9:117-21. 14. Moher D, Liberati A, Tetzlaff J, Altman DG; PRISMA Group (2009). Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med 2009;6: e1000097. 15. Marston W; VIRTUS investigators. VIRTUS trial: pivotal cohort 12-month primary safety and efficacy results of the VICI Venous Stent system. Presented at the Thirty-first Annual Meeting of the American Venous Forum; Rancho Mirage, Calif February 19-22, 2019. 16. Dake MD. Treatment of venous iliofemoral occlusive disease with a self-expanding venous stent: 12-month results from the prospective, multicenter VERNACULAR trial. Presented
19.
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26. 27.
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30.
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33.
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at Vascular Interventional Advances (VIVA) Annual Conference 2018; Las Vegas, Nev November 5-8, 2018. Black S, Gwozdz A, Karunanithy N, Silickas J, Breen K, Hunt B, et al. Two year outcome after chronic iliac vein occlusion recanalisation using the Vici Venous Stent. Eur J Vasc Endovasc Surg 2018;56:710-8. Lichtenberg M, Breuckmann F, Stahlhoff WF, Neglen P, Rick G. Placement of closed-cell designed venous stents in a mixed cohort of patients with chronic venous outflow obstructionsdshort-term safety, patency, and clinical outcomes. Vasa 2018;47:475-81. van Vuuren TM, Doganci S, Wittens CH. Patency rates and clinical outcomes in a cohort of 200 patients treated with a dedicated venous stent. J Vasc Surg Venous Lymphat Disord 2018;6:321-9. Liu Z, Gao N, Shen L, Yang J, Zhu Y, Li Z, et al. Endovascular treatment for symptomatic iliac vein compression syndrome: a prospective consecutive series of 48 patients. Ann Vasc Surg 2014;28:695-704. Sarici IS, Yanar F, Agcaoglu O, Ucar A, Poyanli A, Cakir S, et al. Our early experience with iliofemoral vein stenting in patients with post-thrombotic syndrome. Phlebology 2014;29: 298-303. Neglén P, Hollis KC, Olivier J, Raju S. Stenting of the venous outflow in chronic venous disease: long-term stent-related outcome, clinical, and hemodynamic result. J Vasc Surg 2007;46:979-90. Hartung O, Loundou AD, Barthelemy P, Arnoux D, Boufi M, Alimi YS. Endovascular management of chronic disabling ilio-caval obstructive lesions: long-term results. Eur J Vasc Endovasc Surg 2009;38:118-24. Kölbel T, Lindh M, Akesson M, Wassèlius J, Gottsäter A, Ivancev K. Chronic iliac vein occlusion: midterm results of endovascular recanalization. J Endovasc Ther 2009;16:483-91. Lou WS, Gu JP, He X, Chen L, Su HB, Chen GP, et al. Endovascular treatment for iliac vein compression syndrome: a comparison between the presence and absence of secondary thrombosis. Korean J Radiol 2009;10:135-43. Raju S, Neglén P. Percutaneous recanalization of total occlusions of the iliac vein. J Vasc Surg 2009;50:360-8. Rosales A, Sandbaek G, Jørgensen JJ. Stenting for chronic post-thrombotic vena cava and iliofemoral venous occlusions: mid-term patency and clinical outcome. Eur J Vasc Endovasc Surg 2010;40:234-40. Meng QY, Li XQ, Qian AM, Sang HF, Rong JJ, Zhu LW. Endovascular treatment of iliac vein compression syndrome. Chin Med J 2011;124:3281-4. Kurklinsky AK, Bjarnason H, Friese JL, Wysokinski WE, McBane RD, Misselt A, et al. Outcomes of venoplasty with stent placement for chronic thrombosis of the iliac and femoral veins: single-center experience. J Vasc Interv Radiol 2012;23:1009-15. Ye K, Lu X, Li W, Huang Y, Huang X, Lu M, et al. Long-term outcomes of stent placement for symptomatic nonthrombotic iliac vein compression lesions in chronic venous disease. J Vasc Interv Radiol 2012;23:497-502. Friedrich de Wolf MA, Arnoldussen CW, Grommes J, Hsien SG, Nelemans PJ, de Haan MW, et al. Minimally invasive treatment of chronic iliofemoral venous occlusive disease. J Vasc Surg Venous Lymphat Disord 2013;1:146-53. Blanch AM, Izquierdo Lamoca LM, Ramirez OM, Lagos RI, Zotta DR, Stefanov KS. Endovascular treatment of iliofemoral chronic post-thrombotic venous flow obstruction. J Vasc Surg Venous Lymphat Disord 2014;2:2-7. George R, Verma H, Ram B, Tripathi R. The effect of deep venous stenting on healing of lower limb venous ulcers. Eur J Vasc Endovasc Surg 2014;48:330-6.
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34. Raju S, Ward M Jr, Kirk O. A modification of iliac vein stent technique. Ann Vasc Surg 2014;28:1485-92. 35. Sang H, Li X, Qian A, Meng Q. Outcome of endovascular treatment in postthrombotic syndrome. Ann Vasc Surg 2014;28:1493-500. 36. Ye K, Lu X, Jiang M, Yang X, Li W, Huang Y, et al. Technical details and clinical outcomes of transpopliteal venous stent placement for postthrombotic chronic total occlusion of the iliofemoral vein. J Vasc Interv Radiol 2014;25:925-32. 37. Rollo JC, Farley SM, Jimenez JC, Woo K, Lawrence PF, DeRubertis BG. Contemporary outcomes of elective iliocaval and infrainguinal venous intervention for post-thrombotic chronic venous occlusive disease. J Vasc Surg Venous Lymphat Disord 2017;5:789-99. 38. Rizvi SA, Ascher E, Hingorani A, Marks N. Stent patency in patients with advanced chronic venous disease and nonthrombotic iliac vein lesions. J Vasc Surg Venous Lymphat Disord 2018;6:457-63. 39. Ye K, Shi H, Yin M, Qin J, Yang X, Liu X, et al. Treatment of femoral vein obstruction concomitant with iliofemoral stenting in patients with severe post-thrombotic syndrome. Eur J Vasc Endovasc Surg 2018;55:222-8. 40. Porter JM, Moneta GL. Reporting standards in venous disease: an update. International Consensus Committee on Chronic Venous Disease. J Vasc Surg 1995;21:635-45.
41. Rutherford RB, Padberg FT, Comerota AJ, Kistner RL, Meissner MH, Moneta GL. Venous severity scoring: an adjunct to venous outcome assessment. J Vasc Surg 2000;31:1307-12. 42. Villalta S, Bagatella P, Piccioli A, Lensing A, Prins M, Prandoni P. Assessment of validity and reproducibility of a clinical scale for the post-thrombotic syndrome. Haemostasis 1994;24:158a. 43. Vasquez MA, Rabe E, McLafferty CK, Shortell RB, Marston WA, Gillespie D, et al. Revision of the Venous Clinical Severity Score: venous outcomes consensus statement: special communication of the American Venous Forum Ad Hoc Outcomes Working Group. J Vasc Surg 2010;52:1387-96. 44. Neglen P, Tackett TP Jr, Raju S. Venous stenting across the inguinal ligament. J Vasc Surg 2008;48:1255-61. 45. O’Donnell TF Jr, Passman MA. Clinical practice guidelines of the Society for Vascular Surgery (SVS) and the American Venous Forum (AVF)dmanagement of venous leg ulcers. J Vasc Surg 2014;60:1S-2S. 46. Raju S, Darcey R, Neglen P. Unexpected major role for venous stenting in deep reflux disease. J Vasc Surg 2010;51:401-8.
Submitted Jun 26, 2019; accepted Aug 20, 2019.
ABSTRACT Objective: Endovascular stenting of the deep venous system is increasingly used to treat stenotic and occluded veins. This article reviews the efficacy and safety of venous stenting for lower extremity occlusive disease. Methods: The Ovid portal was used to search the MEDLINE database for English-language randomized controlled trials and case series published between January 1, 2005, and December 31, 2018, involving venous stenting for lower extremity and inferior venacaval occlusive and compressive disease. Studies were eligible for inclusion if they contained at least 30 patients with at least 6 months of follow-up. Clinical outcomes, long-term patency, complications, and postoperative anticoagulation regimens were reviewed. Also included are nationally presented trial results of dedicated venous stents that may not have been formally published yet. Results: Relevant studies were too heterogeneous for a formal meta-analysis to be performed. We analyzed 3812 stented limbs from 23 published studies and two national presentations. Dedicated venous stents were used in 740 patients, and standard stents were used in 3072 patients. The overall major complication rate was <1%. Median symptomatic improvement and ulcer healing were seen in 79% and 71% of the standard stented limbs, respectively. For standard stents, the median primary, assisted primary, and secondary patency rates were 71%, 89%, and 91%, respectively, with a median study follow-up of 23.5 months. Dedicated venous stents had an overall primary patency of 78.8% at 12 months, with lower patency (73%) seen in post-thrombotic vs compressive (96%) disease. Conclusions: Whereas the quality of evidence remains weak, iliocaval venous stenting appears to be a safe and effective treatment of chronic venous disease. In early results, dedicated venous stents appear safe and demonstrate results that are as good as or better than those of historically used devices. (J Vasc Surg: Venous and Lym Dis 2019;-:1-9.) Keywords: Chronic venous disease; Post-thrombotic syndrome; Nonthrombotic iliac vein lesions; Stents
Chronic venous disease (CVD) of the lower extremities is typically associated with leg swelling, pain, skin discoloration, and ulceration. Causes of CVD include postthrombotic syndrome (PTS), nonthrombotic iliac vein lesions (NIVLs), venous reflux due to incompetent valves, and insufficient muscle pump function. Increased venous pressure results in increased capillary permeability, tissue edema, fibrosis, tissue hypoxia, and ulceration. PTS is the development of CVD due to prior deep venous thrombosis (DVT). Scarring from the DVT causes reflux due to valvular incompetence and chronic venous hypertension due to venous obstruction or stenosis. PTS is the most common long-term complication of DVT and is seen in 20% to 50% of patients who have had a prior DVT.1 Severe PTS is seen in only 5% to 10% of
From the Division of Vascular Surgery, Duke University Medical Center. Author conflict of interest: none. Correspondence: Ellen D. Dillavou, MD, Division of Vascular Surgery, Duke University Medical Center, 407 Crutchfield St, Durham, NC 27704 (e-mail: ellen. [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the Journal policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest. 2213-333X Copyright Ó 2019 by the Society for Vascular Surgery. Published by Elsevier Inc. https://doi.org/10.1016/j.jvsv.2019.08.015
patients and is most frequent in those who have had iliofemoral DVT.2,3 Compression of the left iliac vein between the right iliac artery and the vertebra, May-Thurner syndrome, is the most common cause of NIVLs. However, NIVL can be caused by several other anatomic variants and is less frequently seen in the right iliac vein and inferior vena cava (IVC). CVD symptoms are caused by venous hypertension from the outflow stenosis. NIVLs are often asymptomatic and should not be treated in asymptomatic patients.4 It is thought that these asymptomatic lesions can become symptomatic after secondary insults, such as trauma, infection, venous reflux, obesity, lymphedema, surgery, and vasoactive medications. NIVLs are a less common cause of CVD compared with PTS; however, the increased use of intravascular ultrasound (IVUS) has revealed NIVLs to be a more common cause of CVD than was once thought.5-7 The diagnosis of CVD can often be determined by a thorough history and physical examination. Other causes of leg swelling that should be ruled out are acute DVT, heart failure, renal failure, liver failure, medication side effects, and lymphedema. Venous duplex ultrasound is a noninvasive, essential tool for evaluating CVD. It provides information about reflux, occlusion, and stenosis of the leg veins. Disease of the iliac veins can often be inferred from alterations in flow characteristics of the femoral system and may be directly visualized, depending on body 1
2
Williams and Dillavou
Journal of Vascular Surgery: Venous and Lymphatic Disorders ---
habitus, skill and experience of the technologist, and capabilities of the ultrasound machine. Venous plethysmography may also be used to evaluate for reflux in select patients.8 Pelvic and occasionally extremity computed tomography or magnetic resonance venography should be used in patients who have risk factors and clinical features of CVD if venous duplex ultrasound and plethysmography are nondiagnostic. If there is evidence of CVD on noninvasive imaging or if there is high clinical suspicion and treatment would be appropriate, catheter-based venography and IVUS with possible venoplasty and stenting should be used.9,10 Venography has only about 50% sensitivity in detecting iliac vein lesions, whereas IVUS provides a sensitivity of at least 80% and has other advantages over venography.11-13 IVUS is the preferred procedural tool during venous diagnosis and stent placement as it allows three-dimensional visualization of the compressed area as well as precise sizing and deployment. The objective of this systematic review is to provide a description of the risks and outcomes of venous stenting through analysis of larger published data series. This information can then be used as a background for evaluation of new technology, with initial trial data presented.
METHODS The Ovid portal was used to search the MEDLINE database for articles relating to venous stenting that were published in English between January 1, 2000, and December 31, 2018. All studies cataloged in MEDLINE were eligible for review. The date last searched was February 1, 2019. To structure the review, the Preferred Reporting Items for Systematic Reviews and MetaAnalyses guidelines were followed.14 Individual researchers and sponsoring manufacturers were contacted for early trial data on emerging venous stent technology, but only publicly presented or published data are included in this review. Because of the heterogeneous nature of the studies, a meta-analysis could not be performed. The relevant studies were on venous stenting for lower extremity chronic occlusive and compressive venous disease. As the majority of venous stenting literature centered on iliac and IVC occlusive and compressive disease rather than on femoral-popliteal disease, which is variably stented, the decision was made to include the iliac and IVC sites exclusively in an effort to decrease heterogeneity. The Ovid portal was searched using the keywords “venous stenting,” “venous and stents,” or “vein and stent” in combination with “iliac vein stenosis,” “iliac vein compression syndrome,” “nonthrombotic iliac vein lesions,” “iliofemoral occlusion,” “post-thrombotic syndrome,” or “chronic venous insufficiency,” with the limitations of English language and human subjects. This resulted in 164 studies. These studies along with their key reference lists were reviewed by the authors for inclusion. Studies were
2019
chosen for screening if the following criteria were met: full-length article could be procured, condition treated was chronic venous occlusion or nonthrombotic venous compression, >30 patients were described, and median follow-up was at least 6 months. Articles involving the treatment of acute DVT were excluded if the outcomes were not reported separately from the PTS or NIVL patients. All studies were reviewed by the authors. No primary authors were contacted to verify information on published work, although initial work on new technology was obtained from primary authors with the permission of the stent manufacturer. If two articles appeared to contain the same patient samples, the smaller sample size or shorter follow-up of the two articles was excluded. In total, 23 published studies were included. All eligible studies were reviewed regardless of funding source. The data from published studies were pooled and examined in an effort to elucidate overall patency, reintervention rates, and patterns of anticoagulation or antiplatelet therapy during or after the procedure and to look for differences between stent types. Two additional studies15,16 were included in this report on the basis of recent presentation of results using dedicated venous stents. Studies were divided into those using stents that were designed or Food and Drug Administration approved for other uses (standards stents) and those that were specifically designed for use in venous settings (dedicated stents). The majority of dedicated stent trials were performed in Europe as this technology has recently been approved for use in the United States.
RESULTS Following a review of the literature, 20 articles involving 3072 stented limbs using off-label stents (standard stents) were included in this analysis. Three published articles17-19 and two national presentations15,16 of dedicated venous stents were reviewed separately and described 740 patients. Of the 20 studies of standard stents, all but 2 studies20,21 were retrospective reviews. Of these 3072 interventions, 51% of the limbs were stented for PTS and 49% for NIVL (Table I). The majority of studies used the Wallstent (Boston Scientific, Marlborough, Mass), but the Protége (ev3, Plymouth, Minn), S.M.A.R.T. (Cordis, Warren, NJ), Luminexx (Bard/ Angiomed GmbH & Co, Karlsruhe, Germany), Zilver Vena (Cook Medical, Bloomington, Ind), AndraStent XL (BioAssist, Albuquerque, NM), Gianturco Z (Cook Medical), LifeStent (Bard, Tempe, Ariz), and Absolute Pro (Abbott Vascular, Santa Clara, Calif) stents were also used. Clinical outcomes were variably reported by one of the following scoring or quality of life systems: Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) classification,40 Venous Severity Score,41 Villalta score,42 and revised Venous Clinical Severity Score (rVCSS).43 Ulcer healing and patency rates were also reported. For standard stents, median symptom relief, defined as an
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Table I. Study characteristics: Standard stents Study
Study type
No. of limbs treated
No. of PTS cases
No. of NIVLs
Type of stents
Retrospective
982
464
518
Wallstent, nitinol stent (brand not stated)
Hartung,23 2009
Retrospective
89
30
59
Wallstent
Kölbel,24 2009
Retrospective
59
59
0
Wallstent
Lou,25 2009
Retrospective
73
34
39
Luminexx stent
Neglen,22 2007
26
Retrospective
167
167
0
Wallstent
Retrospective
34
34
0
Wallstent
Meng,28 2011
Retrospective
272
0
272
Kurklinsky,29 2012
Retrospective
91
91
0
Ye,30 2012
Retrospective
224
0
224
Friedrich de Wolf,31 2013
Retrospective
63
54
9
Blanch,32 2014
Retrospective
41
41
0
Wallstent, Zilver Vena
George,33 2014
Retrospective
44
31
13
Niti stent, Luminexx stent
Raju,
2009
Rosales,27 2010
Liu,20 2014
Not stated Wallstent, EverFlex, S.M.A.R.T., Luminexx Wallstent Wallstent, sinus-XL, Zilver Vena, AndraStent XL
Prospective
48
12
36
Wallstent
Raju,34 2014
Retrospective
217
163
54
Wallstent, Gianturco Z stent
Sang,35 2014
Retrospective
67
67
0
Wallstent, S.M.A.R.T, Luminexx
Sarici,21 2014
Prospective
59
59
0
Nitinol stent (brand not stated)
Ye,36 2014
Retrospective
118
118
0
Wallstent, LifeStent, EverFlex
Rollo,37 2017
Retrospective
42
42
0
Wallstent, Absolute Pro
Rizvi,38 2018
Retrospective
268
0
268
Ye,39 2018
Retrospective
114
114
0
3072
1580
1492
Total
Wallstent Wallstent, Luminexx
NIVLs, Nonthrombotic iliac vein lesions; PTS, post-thrombotic syndrome.
improvement in the clinical scoring system used, was 79%. Median rate of ulcer healing was 71% with a median follow-up of 23.5 months. Median primary patency, primary assisted patency, and secondary patency were 71%, 89%, and 91%, respectively, with a median followup of 23.5 months (Table II). Fifteen studies of standard stents had separated stent patency results on the basis of patient presentation of PTS vs NIVL lesions. In analysis of these studies as single entities, primary patency, primary assisted patency, and secondary patency in treating thrombotic or occlusive lesions averaged 64%, 79%, and 85% at an average of 33 months of total follow-up. Compressive (NIVL) lesions averaged 93% primary patency and 100% secondary patency at an average of 32 months. One study had patency details on both groups of patients.22 Thirteen studies discussed postthrombotic results20,21,24-27,29,32,33,35-37,39 and two discussed compressive results.30,38 Dedicated venous stents in smaller studies and with early results showed similar clinical results (Table III). In these trials, ulcer healing was not routinely measured, but significant decreases in symptom scores, most often rVCSS, were seen in all studies, with an average decrease of 3.1 points for those studies using rVCSS. Patency data were slightly higher than for the
standard stents with 78.8% primary patency at 12 months overall. Two recent pivotal U.S. trials compared patency data using historic controls at 72% 12-month primary patency and found that the new stents were noninferior to this metric.15,16 For dedicated venous stents, PTS patency was markedly lower (73%) than in patients treated for nonthrombotic compression (96%). Complications. No studies reported any perioperative mortality or pulmonary embolism. Rates of complications were low, with a mean and median rate of 3.0% and 3.4%, respectively, in the use of standard stents. Described complications (Table IV) included access site hematoma, bleeding, arterial injury, retained guidewire requiring open removal, iliac vein rupture requiring conversion to an open procedure, wound complications when concomitant hybrid procedures were preformed, heparin-induced thrombocytopenia, contralateral DVT during follow-up, ipsilateral stent thrombosis within 30 days of the procedure, and stent migration or fracture requiring reintervention. Reporting of complications was variable among the studies. Specifically, access site hematomas, early ipsilateral DVT or stent thrombosis, and contrast material
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Table II. Study outcomes: Standard stents Study
Symptom relief,a %
Ulcer healing, %
Primary patency, %
Primary assisted patency, %
Secondary patency, %
Median follow-up, months
Neglen22
62
58
67
89
93
23
Hartung23
97
100
83
89
93
38
Kölbel24
51
NSb
67
75
79
32
NS
NS
71
NS
NS
6 48
Lou25 26
Raju
79
56
32
58
66
Rosales27
94
57
67
76
91
33
Meng28
94
85
92
NS
NS
46
Kurklinsky29
60
NS
71
90
95
11
30
Ye
89
82
99
100
NS
48
Friedrich de Wolf31
83
NS
74
81
96
9
Blanch32
80
NS
74
87
89
21
George33
NS
60
94
97
NS
15
Liu20
76
71
93
NS
NS
12
69
NS
96
24 36
Raju34
NS
NS
35
Sang
88
100
71
NS
83
Sarici21
69
75
86
NS
90
6
Ye36
71
78
70
90
94
26
84
67
66
NS
75
15
Rollo37 38
Rizvi
67
NS
98
NS
100
24
Ye39
70
61
53
NS
80
22
Median
79
71
71
89
91
23.5
NS, Not stated. a Symptom relief is defined as improvement in pain or edema per the clinical scoring system used. b Not stated or no ulcer patients in the study.
Table III. Dedicated venous stent trials and results
Author
Stent name
Van Vuuren,19 2018
sinusVenous
Material
Study type
Open cell, laser cut, self-expanding nitinol
Single-center retrospective
No. of patients 200: 48 NIVL, 103 PTS, 49 hybrid
CEAP C5 or C6
12-month primary patency
QoL score change
10.5%
68% (92% NIVL, 71% PTS)
3 VCSS
Marston,15 2019
VICI
Self-expanding nitinol closed cell
Prospective multicenter single arm
200: 50 NIVL, 150 PTS
25.4%
84% (98.2% NIVL, 79.8% PTS)
4.4 VCSS
Black,17 2018
VICI
Self-expanding nitinol closed cell
Single-center retrospective
88 PTS
15%
59% PTS
6 Villalta
Lichtenberg,18 2019
VICI
Self-expanding nitinol closed cell
Single-center retrospective
82: 40 NIVL, 42 PTS
15%
94% (100% NIVL, 87% PTS)
3 VCSS
Venovo
Self-expanding nitinol open cell
Prospective multicenter single arm
170: 72 NIVL, 84 PTS
NA
88.3% (96.9% NIVL, 81.3% PTS)
1.7 VCSS
Dake,16 2018 All
740; 31% NIVL, 69% PTS
Average 78.8% (95.8% NIVL, 73.4% PTS)
CEAP, Clinical, Etiology, Anatomy, and Pathophysiology; NA, not applicable; NIVL, nonthrombotic iliac vein lesion; PTS, post-thrombotic syndrome; QoL, quality of life; VCSS, Venous Clinical Severity Score.
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Table IV. Complications: Standard stents Study Neglen22
Complications, No. (%)
Type (No.) of complications
26 (2.6)
Retroperitoneal bleed (1), femoral artery injury requiring open repair (1), femoral artery pseudoaneurysms (3), arteriovenous fistula (1), retained guidewire requiring open removal (1), early ipsilateral DVT/stent thrombosis (8), contralateral DVT (11)
Hartung23
8 (9.0)
Stent migration (2), superficial femoral artery injury treated with a covered stent (1), early ipsilateral DVT/stent thrombosis (2), hemothorax (1), access site hematoma (2)
Kölbel24
3 (5.1)
Retroperitoneal bleed (2), access site hematoma (1)
Lou25
0 (0)
None
13 (7.8)
Early ipsilateral DVT/stent thrombosis (10), contralateral DVT (3)
2 (5.9)
Early ipsilateral DVT/stent thrombosis (2)
26
Raju
Rosales27 28
Meng
Kurklinsky29
0 (0)
None
1 (1.1)
Early ipsilateral DVT/stent thrombosis (1)
Ye30
3 (1.3)
Stent migration (3)
Friedrich de Wolf31
7 (11.1)
Access site hematoma (5), common femoral artery injury (1), heparin-induced thrombocytopenia (1)
Blanch32
1 (2.4)
Femoral artery pseudoaneurysm (1)
George33
2 (4.5)
Access site hematoma (2)
7 (14.6)
Access site hematoma (4), stent migration (2), iliac vein rupture
Liu
20
Raju34
10 (4.6)
Stent migration (2), early ipsilateral DVT/stent thrombosis (8)
Sang
3 (4.5)
Early ipsilateral DVT/stent thrombosis (3)
Sarici21
0 (0)
Ye36
0 (0)
Rollo37
4 (9.5)
35
Rizvi38
0 (0)
Ye39
15 (13.2)
None None Bleeding requiring transfusion (2), early ipsilateral DVT/stent thrombosis (2) None Early ipsilateral DVT/stent thrombosis (15)
Dedicated venous stents Black17
2 (2)
Paralysis after epidural bleed (1), footdrop after stent placed into spinal foramen (1); both injuries permanent
Lichtenberg18
1 (1.2)
Access site hematoma (1)
Marston15
2 (1.2)
Superficial femoral artery injury treated with a covered stent (1), arteriovenous fistula formation (1)
24 (10.0)
Early ipsilateral DVT/stent thrombosis (3), major bleeding (2), stent migration (1), wound infection (11), seroma/lymphocele (6), contralateral DVT (1)
van Vuuren19,a
DVT, Deep venous thrombosis. a Study had large number of hybrid operations.
extravasation appeared to be variably reported by the included studies. When only major bleeding, arterial injury, and nerve damage were included, the rate of complications was 0.5% per limb treated. Complications recorded in trials of dedicated venous stents reflect the same trends as seen with standard stents. Additions to this list would be paralysis due to spinal epidural hematoma and nerve damage due to stent
placed into spinal foramen, both from the same study.17 The overall rate of complications was 8.3% for dedicated venous stents. Authors’ suggested techniques for the operative approach to venous stenting. Placement of a venous stent for the treatment of iliofemoral obstruction is typically performed by ultrasound-guided access of the
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Table V. Postintervention anticoagulation regimen Postprocedure anticoagulationa
Study 22
Neglen
Lifelong aspirin
23
Therapeutic anticoagulation for 6 months
Hartung Kölbel24
Therapeutic anticoagulation for 6 months
Lou25
Therapeutic anticoagulation for 1-6 months
Raju26
Therapeutic anticoagulation for 3-5 days followed by aspirin or prophylactically dosed fondaparinux for 4-6 weeks
Rosales27
Pneumatic sequential pumps; otherwise not stated
Meng28
Not stated
Kurklinsky29
Therapeutic anticoagulation for 2 months
Ye36
Clopidogrel for 6 months
Friedrich de Wolf31
Therapeutic anticoagulation for 6 months
George33
Therapeutic anticoagulation for 3 months followed by lifelong aspirin
Blanch32
Lifelong aspirin
20
Therapeutic anticoagulation for 6 months
Liu
Raju34
Therapeutic anticoagulation for 6 weeks followed by lifelong aspirin
Sarici21
Clopidogrel for 2 months followed by lifelong aspirin
Sang35
Therapeutic anticoagulation for 6 months
30
Therapeutic anticoagulation for 6 months
Rollo37
Aspirin and clopidogrel for 3 months followed by aspirin indefinitely
Ye
Black17 Lichtenberg18
Therapeutic anticoagulation for an “extended” amount of time Therapeutic anticoagulation for 6 months for NIVL and 12 months for PTS
Rizvi38
Clopidogrel for 3 months
van Vuuren19
Therapeutic anticoagulation for 6 months
Ye39
Therapeutic anticoagulation for 6 months
NIVL, Nonthrombotic iliac vein lesion; PTS, post-thrombotic syndrome. a Patients undergoing complex venous reconstructions and with known thrombophilias were continued on therapeutic anticoagulation postoperatively.
ipsilateral femoral vein at the level of the midthigh. Popliteal, profunda, posterior tibial, and internal jugular veins can also be accessed if needed because of anatomic constraints. An appropriately sized (often 10F) sheath is then inserted over the wire. Antegrade venography is used to identify the obstruction. The area of disease is crossed with a guidewire. The patient is heparinized. IVUS may then be used to determine the degree of stenosis and the diameter of the iliac vein, especially in NIVL, as compression is often difficult to appreciate on two-dimensional venography. In cases of chronic occlusive disease and recanalization, it may not be useful to have IVUS. If it is used, IVUS should be used throughout the procedure to ensure proper stent placement and correction of the pathologic process. Stenotic lesions are then predilated with an angioplasty balloon. A self-expanding stent is placed, covering all areas of >50% stenosis with extension into the IVC of about 1 cm if a Wallstent is used to treat compression at the iliocaval junction. Dedicated venous stents can be placed more accurately with less extension into the IVC. If there are additional lesions below the inguinal ligament, the stent should be extended distally, as crossing
the inguinal ligament does not appear to affect patency.44 Great care should be taken not to “jail” the profunda vein as this affects immediate leg swelling and long-term outcomes. Obtaining good outflow and inflow is vital for long-term stent patency. Iliac vein stents are typically oversized by 2 mm, sized by the normal-caliber vein above or below the obstruction. Common stent diameter sizes are 16 mm for the external iliac and femoral veins and 18 mm for the common iliac vein. Once they are in place, the stents are dilated to the size of the native vessel. Post-stenting patency is confirmed with IVUS or venography. Bilateral “kissing stents” can be placed in patients with bilateral common iliac lesions and severe symptoms in both legs, although this situation is relatively rare and so should not be a common occurrence in most practices. Unilateral stenting can result in resolution of mild symptoms in the contralateral leg through decreased cross-pelvis collateral flow in favor of in-line flow. When an iliac vein stent is placed in the setting of an indwelling contralateral stent protruding into the IVC, a fenestration technique may lead to less stent compression compared with staged kissing stent deployment. The wider struts of
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the Gianturco Z stent may allow easier fenestration compared with Wallstents alone.34 Chronic iliocaval occlusions can often be navigated with a directional catheter and a Glidewire (Terumo Interventional Systems, Somerset, NJ) or by specialized crossing catheter systems. Once re-entry into the vena cava is confirmed, the track can be dilated by a sheath and then with angioplasty. A slightly oversized stent should then be deployed. Hyperdilation may be required to compensate for residual stent compression in the setting of chronic iliocaval occlusions. Postoperative considerations. Postoperative anticoagulation recommendations vary considerably. Of the 23 reviewed studies, most regimens give therapeutic anticoagulation for 2 to 6 months, followed by aspirin indefinitely (Table V). Long-term therapeutic anticoagulation is typically given to patients with a known hypercoagulable state requiring lifelong anticoagulation and for patients who undergo complex iliocaval recanalization after total occlusion with a history of DVT. Because of the heterogeneity of the treatment plans and the inability to confidently assign varying disease states or treatment plans to an anticoagulation regimen, no conclusions were able to be drawn from these data. Postoperative stent surveillance is typically performed with duplex ultrasound at 6 weeks, 6 months, and then yearly intervals after stent placement. If symptoms return or duplex ultrasound findings indicate narrowing of >60%, consideration should be given to evaluation of the area with venography or IVUS. With a median primary patency rate of 71% to 78% seen in our review, a significant number of patients will need reintervention.
DISCUSSION Conservative management, consisting of exercise, elevation, compression therapy, and local wound care, is first-line treatment of CVD. If the patient’s symptoms are refractory to conservative management, percutaneous venoplasty and stenting of areas of >50% stenosis should be performed, although some have suggested increasing the threshold of intervention to >60% stenosis for nonthrombotic patients.45 In cases of combined iliac obstruction and infrainguinal reflux, treatment of the proximal lesion is recommended first.40,45 After treatment of the obstructive lesion, many patients will not need treatment of the concomitant reflux.46 Open venovenous bypasses are reserved for severely symptomatic but otherwise healthy and mobile patients who have failed to respond to endovascular therapy. Venous stenting remains an off-label use of standard stents, with the exception of new devices with a venous indication, specifically the Zilver Vena (Cook Medical), Venovo (Bard), sinus-Venous (OptiMed, Ettlingen, Germany), and VICI (Boston Scientific).
In this systematic review of the published literature on the off-label use of bare-metal stents (standard stents) to treat obstructive and nonobstructive venous lesions, we found an overall primary patency and secondary patency of 71% and 91% at nearly 24 months of median follow-up, with consistently higher patency in treatment of nonocclusive lesions. A median of 79% of patients had symptom relief, and 71% of patients with ulcer demonstrated healing. In early trial results of dedicated venous stents, there was an average of 79% primary patency at 12 months. Patients stented for nonobstructive (NIVL) lesions experienced a higher patency of 96% vs those stented for obstructive disease at 73%.
CONCLUSIONS As illustrated in this review, the quality of evidence supporting venous stenting of the lower extremity is low. Despite this, there is widespread use of venous stents to treat lower extremity PTS and NIVL. The existing studies are limited by lack of controls, selection bias, and publication bias. Despite these limitations, this review illustrates a benefit in ulcer healing and in pain and swelling after intervention as measured by quality of life metrics. Venous stenting appears to safe, with no deaths or pulmonary embolisms in any of the included studies. True rates of other complications are difficult to assess as there are no widely accepted reporting guidelines. The rate of complications with dedicated stents was higher than with standard stents, but this may reflect more patients in trial settings or prospective analysis, which favors detection and reporting of complications vs a retrospective review. Given the potential for benefit and low incidence of major complications, current practice guidelines recommend venous stenting for severe lower extremity PTS or venous stasis due to NIVL refractory to conservative management.45 Recently approved dedicated venous stents are currently under active research, some of which are included in this review. With promising preliminary results, venous stenting is likely to continue to be an area of active industry development. Additional high-quality research is needed in this field. The Chronic Venous Thrombosis: Relief with Adjunctive Catheter-Directed Therapy (C-TRACT) trial is a multicenter randomized controlled trial that will evaluate the use of endovascular intervention in patients with PTS. Once it is completed, this study will, it is hoped, provide additional insight into the safety and efficacy of venous stenting for obstructive CVD and how it compares with conservative management.
AUTHOR CONTRIBUTIONS Conception and design: ZW, ED Analysis and interpretation: ZW, ED Data collection: ZW, ED Writing the article: ZW, ED
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Critical revision of the article: ED Final approval of the article: ZW, ED Statistical analysis: Not applicable Obtained funding: Not applicable Overall responsibility: ED ZW and ED contributed equally to this article and share co-first authorship.
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Submitted Jun 26, 2019; accepted Aug 20, 2019.