Indications, technical aspects, and outcomes of stent placement in chronic iliofemoral venous obstruction

BACKGROUND

Iliofemoral venous stent placement (IVS) has evolved to a well-established endovascular treatment modality for chronic iliofemoral venous obstruction (CIVO). Dedicated venous stents gained approval from the US Food and Drug Administration in 2019 and solidified IVS as a defined intervention with clear indications, contraindications, risks, benefits, and procedural management principles. This review focuses on the indications, technical aspects and outcomes of stenting for CIVO. Other aspects pertaining to IVS are covered in other articles that are a part of this series.

METHODS

This study conducted a literature search limited to English articles. Three search strategies were used, and references were managed in Covidence software. Four investigators screened and evaluated articles independently, excluding meta-analyses, clinical trial protocols, and nonrelevant studies. Eligible studies, focused on clinical outcomes and stent patencies, underwent thorough review.

RESULTS

The literature search yielded 1704 studies, with 147 meeting eligibility criteria after screening and evaluation. Exclusions were based on duplicates, irrelevant content, and noniliac vein stent placement.

CONCLUSIONS

Successful IVS for CIVO relies on meticulous patient selection, consistent use of intravascular ultrasound examination during procedures and attention to the technical details of IVS.

Acute and Chronic Ilio-Femoral Venous Reconstruction

Ilio-femoral venous reconstruction has progressed from being only performed by a limited number of pioneers (often using equipment repurposed from other areas of interventional radiology) to a discrete subspecialty of endovascular practice with a dedicated range of tools and increasingly evolved techniques to secure optimal results. This review is intended to reflect the modern practice of ilio-femoral stenting in the acute and chronic settings, from initial patient assessment to completion of procedure and follow-up care.

The TOPOS study

Background: We aimed to study the long-term safety and efficacy of oblique venous stents for post-thrombotic syndrome (PTS) with iliac vein compression. Patients and methods: In the multinational, prospective, single-arm TOPOS study, PTS patients scheduled for endovascular therapy with the sinus-Obliquus® stent and optional distal extension with the sinus-Venous® or sinus-XL Flex® stent were enrolled at eight European vascular centres between October 2016 and December 2020. The primary outcome was primary stent patency at 24 months, and secondary outcomes included the clinical course of PTS (Villalta score, revised Venous Clinical Severity Score [rVCSS], Visual Analog Scale [VAS] of pain), quality of life changes (Chronic Venous Insufficiency Quality of Life Questionnaire, CIVIQ-20), and device-related complications. Results: We enrolled 60 patients (mean age 46±15 years, 68% women, 13% active ulcers): 80% required stent extension (70% below the inguinal ligament). The primary patency rate at 24 months was 80.7% (95%CI 68.1-90.0%); it was higher in patients without vs. those with stent extension (90.9% vs. 78.3%, p=.01). Compared to baseline, the Villalta, rVCSS, pain VAS, and CIVIQ-20 decreased by a median of 8 (interquartile range (IQR): 4-11), 5 (IQR: 3-7), 3 (IQR: 2-5), and 17 (IQR: 6-22) points, respectively; p<.001 for all parameters. Overall, 9 events of acute stent occlusion, 4 symptomatic stent stenosis, and 1 pulmonary embolism occurred. We did not observe major bleeding events or contralateral thrombosis. Conclusions: Endovascular treatment with the oblique stent and optional stent extension was safe and resulted in high patency rates at 24 months. The reduction in PTS severity was substantial and persisted over 2-year follow-up.

A meta-analysis of the medium- to long-term outcomes in patients with chronic deep venous disease treated with dedicated venous stents

OBJECTIVE

This review summarizes the safety profile, stent patency, and clinical effectiveness of dedicated venous stents for the treatment of chronic deep venous disease. The approaches to stenting and post-procedural management of different vascular units are also explored.

METHODS

The MEDLINE and Embase databases were searched for pertinent literature published from January 2010 to January 2023. Outcomes related to post-stenting symptoms and health-related quality of life were described narratively. A meta analysis was conducted to evaluate stent patency, ulcer healing, bleeding, and 30-day stent thrombosis, and these outcomes were presented as proportion event rates.

RESULTS

Seventeen studies were identified comprising of 2218 patients. 62.7% of individuals had post-thrombotic stenosis or occlusion. The majority of patients (78.6%) were noted to have complete occlusions of their deep veins before stenting. Eleven different dedicated venous stents were deployed. At 12 months, the primary patency rate was 83% (95% confidence interval [CI]: 76%-90%), the primary-assisted patency rate was 90% (95% CI: 85%-96%), and the secondary patency rate was 95% (95% CI: 92%-98%). A significant improvement in health-related quality of life was demonstrated after intervention. In total, 68.8% (95% CI: 52.0%-83.7%) of ulcers healed at the last follow-up. The remaining symptomatic changes were described narratively; improvements in pain, venous claudication, and edema after stenting were observed. Seventeen deaths occurred, but none were linked to the stenting procedures. A total of 159 cases (7.2% of patients) of in-stent stenosis were observed, whereas 110 stents (5.0% of patients) were occluded. The incidence of major and minor bleeding was 1.7% (95% CI: 1.0%-2.5%) and 3.2% (95% CI: 1.3%-5.6%), respectively, more commonly seen in patients undergoing hybrid intervention.

CONCLUSIONS

Deep venous stenting using dedicated venous stents is a safe technique to treat chronic deep venous stenosis and/or occlusion. Within the limitations of this study, deep venous stenting is associated with good patency rates and symptomatic improvement.

Effect of stent treatment on hemodynamics in iliac vein compression syndrome with collateral vein

BACKGROUND

Iliac vein compression syndrome (IVCS) leads to blood flow obstruction in the lower extremities and is usually treated with stents, but stenting may worsen the hemodynamics and increase the risk of thrombosis in the iliac vein. The present work evaluates the advantages and disadvantages of the stent on IVCS with a collateral vein.

METHODS

The computational fluid dynamics method is adopted to analyze the preoperative and postoperative flow fields in a typical IVCS. The geometric models of the iliac vein are constructed from medical imaging data. The porous model is used to simulate the flow obstruction in IVCS.

RESULTS

The preoperative and postoperative hemodynamic characteristics in the iliac vein are obtained, e.g., the pressure gradient at two ends of the compressive region and the wall shear stress. It is found that the stenting restores the blood flow in the left iliac vein.

CONCLUSION

Impacts of the stent are classified into short-term and long-term effects. The short-term effects are beneficial in relieving IVCS, i.e., shortening the blood stasis and reducing the pressure gradient. The long-term effects increase the risk of thrombosis in the stent, i.e., enlarging wall shear stress due to a large corner and a diameter constriction in the distal vessel, and suggests the need to develop a venous stent for IVCS.

Clinical outcomes of different endovenous procedures among patients with varicose veins and iliac vein compression: A retrospective cohort study

OBJECTIVE

This study aimed to investigate the short-term outcomes of three endovenous procedures in patients with varicose veins (VVs) and severe iliac vein compression syndrome (IVCS).

METHODS

A total of 158 consecutive patients were included in this multicenter retrospective study from May 2017 to December 2019; 54 patients underwent endovenous laser ablation (EVLA) alone, 47 patients underwent EVLA and balloon angioplasty (BA), and 57 patients underwent EVLA and stenting angioplasty (SA). Clinical outcomes and complications were assessed at one and twelve months post-surgery. The Quality of life (QoL) was assessed by the venous clinical severity score (VCSS) and Aberdeen Varicose Vein Questionnaire (AVVQ).

RESULTS

Patients who underwent the SA procedure were older (P < 0.05). Incidence of laser ablation complications was similar among the three procedures; closure rates of the great saphenous vein were 96.8%, 98.0%, and 98.4%, respectively, at 12 months. Reflux times in the SA procedure were lower than those in the EVLA and BA procedures at 12 months, while ulcer healing time was faster with the SA procedure (P < 0.05) than with the other procedures. The VCSS and AVVQ values were significantly improved post-procedure (P < 0.05), with lower AVVQ scores in the SA procedure than in the EVLA and BA procedures at 12 months post-surgery. The EVLA and BA procedures (stenosis >70%) caused a significantly higher symptom recurrence than the SA procedure, with an odds ratios of 14.04 (95% confidence interval (CI), 1.99-99.18) and 10.50 (95% CI, 1.26-87.15), respectively.

CONCLUSIONS

Our results demonstrate that EVLA and SA procedures relieve symptoms, improve the QoL, and decrease symptom recurrence in patients with VVs and severe IVCS (stenosis >70%).

An overview of in-stent restenosis in iliofemoral venous stents

BACKGROUND

Although endovenous stents have been associated with overall low morbidity, they can require reinterventions to correct stent malfunction due to in-stent restenosis (ISR). ISR has often occurred iliofemoral venous stents but has not been well described. It has been reported to develop in >70% of patients who have undergone iliofemoral venous stenting. We sought to provide an overview of ISR in iliofemoral venous stents, including the pathologic, diagnostic, and management considerations and the identification of several areas of potential research in the future.

METHODS

A search of reported English-language studies was performed in PubMed and the Cochrane Library. "In-stent restenosis," "vein," "venous," "iliac," and "iliofemoral" were used as keywords. The pertinent reports included in the present review had addressed the pathology, diagnosis, and current management options for ISR.

RESULTS

ISR refers to the narrowing of the luminal caliber of the stent owing to the development of stenosis inside the stent itself. ISR should be differentiated from stent compression. Two main types of ISR have been described: soft and hard lesions. These lesions respond differently to angioplasty. Stent inflow and shear stress are important factors in the development of ISR. The treatment options available at present include balloon angioplasty (hyperdilation or isodilation), laser ablation, atherectomy, and Z-stent placement.

CONCLUSIONS

Reintervention for ISR should be determined by the presence of residual or recurrent symptoms and not simply by a numeric value obtained from an imaging study. Overall stent occlusion due to ISR is rare, and no role exists for prophylactic angioplasty to treat asymptomatic ISR. The current treatment options for ISR are mostly durable and effective. However, more research is needed on methods to prevent the development of ISR. The role of antiplatelet and anticoagulant agents in the prevention of ISR requires further investigation, with particular attention to unique subset of patients (after thrombosis vs nonthrombotic iliac vein lesions). For high-risk, post-thrombotic patients, anticoagulation can be considered to prevent ISR. The role of triple therapy (anticoagulation and dual antiplatelet therapy) in the prevention of ISR remains unclear.

Comparison of endovascular strategy versus hybrid procedure in treatment of chronic venous obstructions involving the confluence of common femoral vein

OBJECTIVE

Treatment of extensive chronic venous obstruction (CVO) with post-thrombotic trabeculation involving the common femoral vein with extension into the femoral vein or deep femoral vein remains a challenge and the best treatment technique for such cases is not clear. In the present study, we compared the results of endovascular alone vs endovascular with additional endophlebectomy (hybrid) procedures for such patients.

METHODS

The medical records of 102 consecutive patients (108 limbs) treated between 2015 and 2020 for iliofemoral CVO extending to the femoral confluence were retrospectively reviewed. The patients were divided into two groups: the hybrid procedure (HP) and endovascular treatment (EN) groups. The HP group consisted of those treated with stent implantation and endophlebectomy of the common femoral vein with creation of an arteriovenous fistula. The EN group included those who had undergone stent implantation alone. The patency rates, complications, and clinical outcomes were analyzed.

RESULTS

Of the 102 patients, 47 (49 limbs) were in the EN group and 55 (59 limbs) were in the HP group. The demographics of the two groups were similar with no statistically significant differences in cumulative primary, assisted primary, or secondary patency rates at 36 months (33.7% vs 36.3%, P = .839; 59.8% vs 64%, P = .941; 69% vs 72.7%, P = .851; respectively). The patients in the EN group, however, had better clinical improvement with a lower postoperative complication rate (P = .012), shorter procedure duration (P < .001), and shorter hospital stay (P = .025).

CONCLUSIONS

The EN and HP both provided similar patency rates for patients with CVO extending into the femoral confluence. The endovascular strategy has the benefit of fewer postoperative complications and a shorter procedure duration and hospital stay compared with the HP.

What are the ideal characteristics of a venous stent?

Historically, the stents used in the venous system were not dedicated scaffolds. They were largely adapted arterial stents. An essential feature of a venous stent is compliance, in order to adapt its crosssectional area to the vein. It should also be crush resistant, corrosion resistant and fatigue resistant. The material should be radiopaque, for follow-up. Another characteristic of the ideal venous stent is flexibility, to adapt its shape to the vein, not vice versa. The scaffold should be uncovered too, in order to avoid the occlusion of collaterals. The ideal venous stent should not migrate, so it is necessary a large diameter and a long length. The radial force is important to prevent migration. However, current stents derived from arterial use display high radial force, which could affect the patency of the thin venous wall. Alternatively, if the stent has an anchor point, that permits a passive anchoring, the radial force required to avoid migration will be lower. Dedicated venous stents were not available until very recently. Furthermore, there is a preclinical study about a new compliant nitinol stent, denominated Petalo CVS. Out of the commonest causes of large veins obstruction, dedicated venous stent could also treat other diseases described more recently, such as the jugular variant of the Eagle syndrome, JEDI syndrome and jugular lesions of the chronic cerebrospinal venous insufficiency that result unfavorable for angioplasty according to Giaquinta classification.

The effect of stent compression on in-stent restenosis and clinical outcomes in iliac vein compression syndrome

Background

To evaluate the effect of stent compression on in-stent restenosis (ISR) and clinical outcomes in patients with iliac vein compression syndrome (IVCS) after iliac vein stenting.

Methods

Fifty patients with IVCS treated with iliac vein stenting (Smart Control, Cordis, USA) between March 2017 and October 2018 were consecutively enrolled in this study. Computed tomography venography (CTV) was performed to assess stent compression and ISR. Based on the degree of stent compression, patients were allocated to a significant stent compression (SSC) group and an insignificant stent compression (ISC) group. The incidence of ISR was analyzed between the SSC and ISC groups. Patients' venous clinical severity scores (VCSSs) and responses to the chronic venous insufficiency questionnaire (CIVIQ) one year after stenting were compared between the two groups to evaluate the clinical improvement of venous insufficiency.

Results

In total, 34% of patients had SSC. There were significant differences in the incidence of ISR (52.9% vs. 21.2%, P=0.023), and in each group, there was one case of stent occlusion (5.88% vs. 3.03%, P=0.999). Patients in the SSC group had a higher VCSS score (8.41±5.92 vs. 3.15±2.87, P=0.04) and a lower CIVIQ score (83.35±8.86 vs. 92.21±4.32, P=0.001).

Conclusions

SSC has a significant effect on the incidence of ISR and the clinical outcomes of venous insufficiency. Thus, a dedicated iliac venous stent with sufficient radial resistive force, crush resistance, and outward radial force is needed to prevent the occurrence of stent compression.

Long-term outcome of dedicated venous stents in management of chronic iliofemoral obstruction

OBJECTIVE

To study the long-term outcomes in patients with occlusive Iliofemoral chronic venous insufficiency (CVI) of benign etiology treated by dedicated venous stents (Zilver Vena stents; Cook, Bloomington, Ind) placed at a single center.

METHODS

We performed retrospective analysis of prospectively collected data from 58 patients with symptomatic benign lower limb CVI during the period from January 2013 to October 2020. Patients underwent recanalization using Zilver Vena stents at Ain Shams University hospitals. We excluded patients requiring stenting after intervention for acute deep venous thrombosis, CVI due to malignancy or vascular malformations, previous ipsilateral venous interventions, or CVI due to nonobstructive pathology (reflux). Patients were clinically classified at enrollment by the clinical, etiology, anatomy, pathology class, venous disability score, and Villalta score. Primary, assisted primary, and secondary stent patency were assessed. Patients were followed clinically and by duplex, at 1, 3, 6, 12 months and annually for 5 years.

RESULTS

There were 31 males and 27 females, with ages ranging between 25 and 60 years (mean, 43.84 years). All patients had post-thrombotic syndrome with a mean Villalta score of 16.8 (range, 10-31). Patients were treated with dedicated venous stents and had a median follow-up of 60 months. The median venous disability score was 3 at the start of the study with a significant decrease to 1 at 5-year follow-up (P < .001). Twelve-month primary patency, assisted primary patency, and secondary patency were 91.4%, 96.6%, and 98.3%, respectively. At the 5-year follow-up, primary patency was 60.3%, assisted primary patency 65.5%, and secondary patency 81%. There were no instances of stent fracture, migration, or structural deformities.

CONCLUSIONS

Treating iliofemoral venous occlusive disease with a dedicated venous stent is an excellent choice for patients with occlusive post-thrombotic syndrome. The technique has good 1-year and 5-year patency and is associated with significant clinical improvement and few complications.

A systematic review and meta-analysis of the treatment of obstructive chronic deep venous disease using dedicated venous stents

OBJECTIVES

This review aims to summarise the efficacy and safety of dedicated venous stenting for the treatment of obstructive chronic deep venous disease. The approaches to stenting and post-procedural management of different vascular units are also highlighted.

METHODS

MEDLINE and Embase were searched to identify relevant literature on dedicated venous stents published from January, 2010 to May, 2020. The patient population and study characteristics; procedural characteristics; and outcomes related to post-stenting symptoms, health-related quality of life, patency and complications were analysed.

RESULTS

Sixteen single-arm observational studies were included from 2,366 studies identified from key-word searches. In total, 1,688 patients were included, of which 70.5% had post-thrombotic syndrome and the remainder had non-thrombotic iliac vein lesions. Nine studies (n = 848), stated whether lesions were stenotic (36.6%) or occlusive (63.4%). Seven studies did not report the lesion characteristics (n = 840). Eight different dedicated venous stent brands were employed. 73.4% of ulcers healed at last follow-up. The remaining symptomatic changes were described narratively; sustained improvements in pain, venous claudication and oedema following stenting were observed. Significant post-stenting improvements in health-related quality of life were noted, as measured by the Chronic Venous Insufficiency Questionnaire-20 instrument. Overall, the most frequently reported complications were in-stent occlusion (n = 204), in-stent stenosis (n = 149) and minor bleeding (n = 77). At 12 months, the primary patency ranged from 59% to 94%, whilst the secondary patency ranged 87% to 100%. The pooled-primary and secondary stent patency rates at 12 months were 74.0% and 90.4%, respectively. The incidence of major and minor bleeding was 1.9% and 4.7%, respectively; bleeding complications were more common in patients undergoing hybrid intervention.

CONCLUSION

Deep venous stenting using dedicated venous stents is a safe technique to treat obstructive chronic deep venous disease and within the limitations of this study, is associated with good patency outcomes and symptomatic improvement.

Self-Expandable Nitinol Stents for the Treatment of Nonmalignant Deep Venous Obstruction

BACKGROUND

Angioplasty with stent placement is a therapeutic option for patients with acute thrombotic, postthrombotic, and nonthrombotic obstruction of the iliofemoral veins or inferior vena cava. Previous studies of steel-alloy stents described variable patency rate across indications.

METHODS

The prospective Swiss Venous Stent Registry includes patients treated with self-expandable nitinol stents for deep venous obstruction. Routine follow-up visits include serial duplex ultrasound for stent patency assessment. The primary outcome was primary stent patency. The secondary outcome was venous thromboembolisms. We studied the rate of stent occlusion and potentially contributing factors.

RESULTS

We included 379 patients: 160 with acute thrombotic, 193 with postthrombotic, and 26 with nonthrombotic deep vein obstruction. The mean age was 46±18 years; 55% were women. The cumulative 3-year primary patency rate was 80.5% (95% CI, 73.0%-88.0%) for acute thrombotic, 59.2% (95% CI, 50.4%-68.0%) for postthrombotic, and 100% for nonthrombotic obstruction (log-rank, P<0.0001). Annualized rates of stent occlusion or venous thromboembolism were 7.8 (acute thrombotic), 15.0 (postthrombotic), and 0 (nonthrombotic) events/100 patient-years. In a multivariable Cox regression model, postthrombotic femoral veins at baseline (hazard ratio, 2.64 [95% CI, 1.53-4.56]) and the number of stents (hazard ratio, 1.22 [95% CI, 1.06-1.40]) were associated with stent occlusion after conditioning for age, sex, and clinically relevant factors.

CONCLUSIONS

The rate of stent occlusion (patency loss) and venous thromboembolism varies substantially across indications, also with dedicated venous nitinol stents. Patients with postthrombotic femoral veins and those who received multiple stents were characterized by the highest risk. Registration: URL: https://clinicaltrials.gov. Unique identifier: NCT02433054.

A retrospective comparison of thrombectomy followed by stenting and thrombectomy alone for the management of deep vein thrombosis with May-Thurner syndrome

OBJECTIVE

To summarize the clinical results of thrombectomy with stenting (TBS) in patients with deep venous thrombosis (DVT) secondary to May-Thurner syndrome (MTS) compared with the outcomes in patients treated with thrombectomy alone (TB).

METHODS

A retrospective observation of patients with proximal DVT secondary to MTS was conducted in our institution. Patients accepted treatment including either catheter-directed TBS or TB. The complications and stent patency rates were recorded after treatments. The clinical results were assessed in both groups. The independent predictors for in-stent restenosis were further calculated in this study.

RESULTS

We included 372 patients with DVT secondary to MTS. Two hundred twenty-one patients received treatment with thrombectomy with TBS and 151 with TB. A longer mean procedure time (65.1 ± 13.9 minutes vs 49.5 ± 15.7 minutes; P < .001) and higher venous perforation rate (23 patients vs 5 patients; P = .011) were observed in the TBS group than in the TB group. The median follow-up time was 34 months. The patency rates in the TBS group at 36 months were as follows: primary patency rate of 74.0% and secondary patency rate of 92.1%. Independent predictors for restenosis included visible remaining collateral vessels (hazard ratio [HR], 1.12-3.29; P = .02), residual thrombus (HR, 1.40-4.38; P = .002), and tapered iliac vein (HR, 1.26-4.06; P = .006). Clinical results, including Venous Clinical Severity Scores (TBS, 8.0 ± 3.0; TB, 11.4 ± 3.2), Chronic Venous Insufficiency Questionnaire score (TBS, 76.4 ± 4.0; TB, 83.1 ± 4.6), Villalta scores (TBS, 3.8 ± 1.7; TB, 6.6 ± 3.2), and edema scores (TBS, 0.7 ± 0.7; TB, 1.6 ± 0.6), improved significantly in the TBS group.

CONCLUSIONS

TBS is effective and feasible for patients with proximal DVT secondary to MTS. Furthermore, compared with TB, additional stenting might be effective in improving the venous clinical results at follow-up observations.

Best practices in diagnosis and treatment of chronic iliac vein obstruction

Iliac vein obstruction occurs in 20-30% of the general population. In patients with severe chronic venous insufficiency, this prevalence can be even higher, reaching 50-90% when the obstruction is investigated using intravascular ultrasound. Less invasive methods, such as venous Duplex Scanning, and even invasive ones such as venography may fail to diagnose the condition. Endovascular treatment of these obstructions is effective, safe, and associated with excellent clinical outcomes and stent patency rates, provided that fundamental anatomical and technical principles are considered and applied.

Use of the VENOVO™ and Sinus Obliquus™ venous stents in the treatment of non-thrombotic or post-thrombotic iliac vein lesions - Short-term results from a multi-centre Asian cohort

OBJECTIVES

Deep venous stenting with intravascular ultrasound (IVUS) guidance is gaining favour as the treatment modality of choice for symptomatic ilio-femoral venous occlusive disease. The aim was to determine the short-term patency and symptomatic relief gained using the Bard Venovo™ and Optimed Sinus Obliquus™ stents in the endovascular treatment of non-thrombotic iliac vein lesions (NIVL) and post-thrombotic venous obstruction (PTO) from two Asian tertiary vascular centres.

METHODS

Sixty patients (males = 21/60 (35.0%); median age 67 years (interquartile range 54-77)) who underwent IVUS interrogation and ilio-femoral stenting (June 2018-May 2019) in two Asian centres were prospectively followed. Clinical improvement was determined by the revised Venous Clinical Severity Score (rVCSS), pain using the Visual Analogue Scale (VAS) and ulcer healing rate. Patency rates were evaluated using Duplex ultrasound and computer tomography venogram.

RESULTS

Seventy-one legs were interrogated and stented; 11/60 (18.3%) patients had a bilateral procedure. Indications for surgery were PTO (n = 11/71 (15.5%)) and NIVL (n = 60/71 (84.5%)). Twenty-seven of 71 (38.0%) patients had CEAP 6 disease. The median follow-up was 283 (interquartile range 211-370) days. Technical and procedural success was both 100%. Twenty-one of 71 (29.6%) legs had a combination of Venovo™ and Sinus Obliquus™ stents inserted for concurrent ilio-caval and iliac lesions. There were no major post-operative complications. Six-month primary, assisted primary and secondary patency rates were 94.1, 97.1 and 100%, respectively. There were no stent fractures. Mean rVCSS and VAS improved from 12.26 (±3.31) to 4.33 (±2.78) and 6.97 (±1.38) to 2.03 (±1.65), respectively, at three months (p < 0.01). Complete ulcer healing was seen in 27/27 (100%) patients at three months.

CONCLUSION

Use of Venovo™ and Sinus Obliquus™ stents for symptomatic ilio-femoral venous disease showed excellent six-month primary patency rate with no stent fractures. There were significant clinical improvement and low-device-related complications. Longer follow-up is awaited to see how these dedicated venous stents perform.

Duplex Ultrasound Investigation for the Detection of Obstructed Iliocaval Venous Stents

OBJECTIVE

Duplex ultrasound (DUS) is used for routine surveillance of stents in iliocaval veins, but direct visualisation is often challenging. Duplex ultrasound criteria for detecting venous stent obstruction (VSO) have not been defined to date.

METHODS

A nested case control study of 120 patients (42 ± 17 years, 53% women, mean 2.7 ± 1.8 stents) was performed, and the performance of various duplex parameters for detecting VSO (defined as > 50% lumen diameter reduction or occlusion) was tested, confirmed by biplane venography or intravascular ultrasound (IVUS). Forty patients with VSO (25 with stent occlusion, 15 with >50% in stent stenosis) were matched to 80 control patients by age, gender and index diagnosis who fulfilled the following criteria: (1) ongoing symptom control (Villalta score < 5), (2) good image quality of entire stent segment, (3) spontaneous colour Doppler signal > 50% of lumen in entire stent segment, (4) at least two DUS where the baseline DUS was obtained within 24 h after successful venous intervention.

RESULTS

The best test was the combination of peak flow velocity and flow pattern analysis at the stent inlet. A peak flow velocity >10 cm/s and a flow pattern spontaneously modulated by respiration ruled out VSO with a specificity of 93.7% (95% CI 86.0%-97.3%). A peak flow velocity ≤10 cm/s or any Doppler flow pattern other than spontaneously modulated by respiration was 92.1% (95% CI 79.2%-97.3%) sensitive to detect VSO.

CONCLUSION

The combination of peak flow velocity and analysis of Doppler flow pattern at the stent inlet is accurate to diagnose or rule out stent occlusion. Indirect criteria should always be combined with direct visualisation of iliocaval stents since those may be less sensitive for detecting stent stenosis.

Early clinical outcomes for treatment of post-thrombotic syndrome and common iliac vein compression with a hybrid Oblique self-expanding nitinol stent – the TOPOS study

Summary: Background: Physical attributes of conventional stents used in the ilio-caval territory are often unfavorable in the presence of external compression close to the bifurcation. A hybrid oblique stent was developed for the treatment of common iliac vein compression without compromising the contralateral iliac vein inflow. Patients and methods: The ongoing international monitored TOPOS study enrolled 60 patients with post-thrombotic syndrome (PTS) treated with the sinus-Obliquus stent (optimed) and provisional distal stent extension. At 3-month follow-up, patency rates were obtained from duplex ultrasound, and clinical outcomes were assessed by the Villalta score, revised venous severity score (rVCSS), pain intensity score and chronic venous disease quality of life questionnaire (CIVIQ-20). Results: Mean age was 46.6 ± 14.9 years (68.3 % women). Mean number of implanted stents was 1.9 ± 0.6; 12 (20 %) patients received the hybrid oblique stent only. Forty-eight (80 %) patients had distal stent extension, and 42 (70 %) had stents below the inguinal ligament. Four (7 %) patients (all with stent extension) developed stent thrombosis. Primary and secondary patency rates at 3 months were 93.1 % (95 %CI 83.3–98.1 %), and 100 % (95 %CI 93.8–100 %), respectively. Improvement in Villalta, rVCSS, CIVIQ-20, and pain intensity score from baseline to 3-month follow-up was 6.9 ± 1.4 points (95 %CI 4.1–9.8; p < 0.0001), 3.4 ± 1.0 points (95 %CI 1.3–5.4 points; p < 0.01), 13.6 ± 2.7 points (95 %CI 8.2–19.0 points; p < 0.0001), and 2.4 ± 0.5 (95 %CI 1.4–3.3; p < 0.0001), respectively. At follow-up, 38 (63 %) patients were free from the PTS and none developed contralateral deep vein thrombosis. Conclusions: In patients with PTS and common iliac vein compression, treatment with the hybrid oblique stent with provisional stent extension resulted in high patency rates and improvement in PTS severity and quality of life at 3-month. Two-year results of TOPOS will assess the durability of this treatment.

May-Thurner syndrome: History of understanding and need for defining population prevalence

Patients with May-Thurner syndrome (MTS) are at elevated risk of developing an extensive left iliofemoral deep vein thrombosis (DVT; localized blood clot) due to an anatomical variant where the right common iliac artery compresses the left common iliac vein against the lumbar spine. While MTS was initially presumed to be rare when it was first anatomically defined in 1957, case reports of this syndrome have recently become more frequent, perhaps due to improved imaging techniques allowing for enhanced visualization of the iliac veins. Still, the population burden of this condition is unknown, and there is speculation it may be higher than generally perceived. In the present review, we (a) review history of how MTS became recognized, (b) describe practical challenges of studying MTS in population-based settings due to the specialized imaging required for diagnosis, (c) discuss why the contribution of MTS to DVT may be underestimated, (d) describe uncertainty regarding the degree of venous compression which leads to DVT, and (e) outline future research needs. Our goal is to raise awareness of MTS and spark additional research into the epidemiology of this condition, which may be an underappreciated causative venous thromboembolism risk factor.

Contralateral deep vein thrombosis after stenting across the iliocaval confluence in chronic venous disease – A systematic review

Objective

Stenting of the iliac veins is increasingly considered in the presence of symptomatic obstructive chronic lesions in the iliac vein segment. However, it is often necessary to extend the stented zone into the inferior vena cava, increasing the risk of contralateral iliac vein thrombosis. This study aims to review the current literature concerning the incidence of contralateral deep vein thrombosis after stenting across the iliocaval confluence.

Methods

A systematic review from potentially relevant published articles reporting contralateral deep vein thrombosis after iliac venous stenting between January 2007 and February 2019 was performed.

Results

A total of 764 references were retrieved initially. Twelve studies reporting events of contralateral deep vein thrombosis were selected for review, with a total of 1864 patients. Contralateral deep vein thrombosis incidence varied between 0% and 15.6%. The post-interventional and follow-up anticoagulation regimens were heterogeneous between studies. The decision to maintain patients on anticoagulation and the duration of treatment was based on the presence of comorbidities, hypercoagulable states, post-thrombotic syndrome and history of recurrent deep vein thrombosis. Patients with non-thrombotic iliac vein lesions were either anticoagulated for three or six months after stenting or received no anticoagulation. Patients with post-thrombotic syndrome were anticoagulated for longer periods. Most studies (eight studies) used an oral vitamin K antagonist agent. The data on compliance with anticoagulation treatment is scarce and few references present data on whether contralateral deep vein thrombosis occurred during anticoagulation treatment. The use of antiplatelet agents in addition to the anticoagulant treatment in the follow-up period was also variable.

Conclusion

The incidence of contralateral deep vein thrombosis due to iliac vein jailing is not negligible and reported being as high as 15.6%. Large-scale studies on the ideal antithrombotic treatment and its impact are necessary. It is possible that patients with stent crossing the iliocaval confluence might benefit from long-term antithrombotic treatment.

The clinical outcome of a one-stop procedure for patients with iliac vein compression combined with varicose veins

BACKGROUND

Primary iliac vein compression syndrome (IVCS) often is manifested with varicose veins (VVs), but the treatment of patients with IVCS combined with VVs remains unclear. The aim of this study was to investigate the outcome of a one-stop procedure for patients with IVCS and VVs.

METHODS

The 32 enrolled patients underwent iliac stenting first and then endovenous laser ablation for VVs. The reflux time of the femoral vein, peak reflux velocity, and mean flow velocity were measured, and the effect on quality of life was also assessed using the Aberdeen Varicose Vein Questionnaire and Venous Clinical Severity Score. All clinical data have been recorded and analyzed.

RESULTS

The success rate of the procedures was 100%. No serious complications occurred. The Aberdeen Varicose Vein Questionnaire score and Venous Clinical Severity Score of patients were significantly lower at 1 month, 6 months, and 12 months after the procedure compared with scores before the procedure (P < .01). The reflux time and peak reflux velocity were lower at 6 and 12 months after the procedure (P < .01), and the mean flow velocity was higher at 6 and 12 months after the procedure (P < .05). The patency rate of the iliac vein stent was 100% during follow-up, and one patient (3.13%) had a restenosis without symptoms.

CONCLUSIONS

The one-stop procedure for patients with IVCS combined with VVs is a safe and effective method that might be a therapy choice for these patients.

Study on the Patency of the Contralateral Iliac Vein After Stenting Across the Iliocaval Confluence With an Experimental In Vivo Model

OBJECTIVE

Stenting is the preferred treatment for iliac vein lesions. For the treatment of occlusions in the junction of the iliac vein and the inferior vena cava (IVC), the stent needs to be positioned in the IVC to cover the lesion. However, the pathological changes in the contralateral iliac vein due to stent coverage on its ostium remain unclear. We observed the patency of the contralateral iliac vein via animal experiments.

METHODS

The stents were placed in the left iliac vein and extended into the IVC in 8 beagle dogs. Doppler ultrasonography, angiography, and histopathological examination were used to assess the patency and histopathological changes in the contralateral iliac vein.

RESULTS

Angiography showed patency of the contralateral iliac vein and no sign of thrombosis or stenosis. Twelve months after stenting, Doppler ultrasonography showed a stenotic change in the ostium of the contralateral iliac vein. The histopathological examination showed that the stent strut at the ostium of the contralateral iliac vein was mostly covered by the intima, and the cross-sectional stenosis rate was greater than 60%.

CONCLUSIONS

The coverage of the iliac vein stent on the ostium of the contralateral iliac vein does not cause complete occlusion of the contralateral vein but can cause significant stenosis at the ostium of the contralateral iliac vein, which is considered to be a potential risk factor for thrombosis.

Update on diagnosis and treatment strategies in patients with post-thrombotic syndrome due to chronic venous obstruction and role of endovenous recanalization

OBJECTIVE

After a first episode of lower extremity deep venous thrombosis, post-thrombotic syndrome (PTS) develops in 20% to 50% of patients despite adequate anticoagulation. Symptoms of PTS can vary from leg swelling to venous ulceration with disabling venous claudication. It significantly affects the patient's quality of life and has considerable socioeconomic consequences. This review gives an update on diagnosis and current treatment strategies in patients with PTS due to chronic venous obstruction, in particular regarding the role of endovenous procedures.

METHODS

This review article is based on a selective literature search in PubMed and the Cochrane Library. The terms "postthrombotic syndrome," "post-thrombotic syndrome," "chronic venous obstruction," "venous outflow obstruction," and "venous stent" were used as keywords. Selected publications addressed the diagnosis of and therapy for PTS. Acute deep venous thrombosis, thrombolysis, case reports, complications as a result of caval vein filters, animal experiments, PTS of the upper extremity, and PTS in children were excluded.

RESULTS

In addition to conservative treatment of PTS, the following invasive procedures are also available: open surgical reconstructions, hybrid procedures, and endovenous recanalization of the occluded iliocaval venous tract with stent angioplasty. Since introduction of dedicated venous stents in 2012, technical success, patency rates, and improvement in quality of life have been at least as good as results of open surgical reconstruction if not better.

CONCLUSIONS

First-line treatment should be conservative therapy. In case of therapy-resistant PTS with poor quality of life, the possibility of an invasive treatment should be evaluated. All invasive procedures are recommended with low levels of evidence. Therefore, deciding on an invasive treatment and type of procedure should be made individually. Because PTS is rarely a threat to life or limb, a minimally invasive treatment is preferred. Therefore, endovenous recanalization appears to be appropriate as the therapy of choice. In patients with involvement of the femoral confluence, endophlebectomy of the common femoral vein in addition to venous recanalization is inevitable to ensure an adequate inflow into the recanalized venous tract. It also secures a sufficient drainage of blood from the peripheral venous system. Because this hybrid procedure is burdened with a significantly higher risk of complications, strict criteria must be fulfilled to legitimize the indication for this procedure. For the best possible results to be achieved, the following perioperative and postoperative management must be considered: therapeutic anticoagulation, early mobilization, compression therapy, and systematic follow-up with duplex ultrasound.

Venovo venous stent in the treatment of non-thrombotic or post-thrombotic iliac vein lesions – short-term results from the Arnsberg venous registry

Abstract. Background: We sought to determine the patency and clinical symptom relief of the Venovo venous stent in the endovascular treatment of non-thrombotic (NIVL) or post-thrombotic venous obstruction (PTO) of the iliofemoral track over a period of 6 months. Patients and methods: A total of 80 patients (45 female, mean age 57 years) treated in 2016 and 2017 were included in the Arnsberg venous registry. Clinical improvement was determined by the revised venous clinical severity score (rVCSS) as well as the clinical, etiologic, anatomic and pathophysiologic (CEAP) score. Primary and secondary stent patency was evaluated using duplex ultrasound. Results: Overall 6-months patency rates were 98 % for primary and 100 % for secondary patency. For NIVL primary patency was 97 %, whereas for PTO primary patency was 96 %. Early stent re-occlusion occurred in 3 patients within 34, 59 and 156 days after intervention. Two of these patients were successfully treated by endovascular mechanical thrombectomy and stent in stent implantation. Clinical improvement with a gain of ≥ 2 rVCSS levels was observed in 51 %. CEAP scores decreased from 4.3 to 2.7. Conclusions: In this first time report the novel Venovo venous stent showed adequate patency rates associated with reasonable clinical improvement and low device-related complications throughout a 6-months-follow-up in both NIVL and PTO.

Relevance of flexibility versus radial force in rigid versus more flexible venous stents?

Introduction

Deep venous stenting has gained increasing interest. More flexible venous stents are thought to gain superior clinical outcomes. This research evaluated the patency and clinical outcomes between more rigid stents and more flexible stents.

Material and methods

The Venous Clinical Severity Score, Villalta, complication rates and patency rates were evaluated. The more rigid stents included the Sinus XL, the Veniti VICI and the Sinus Obliquus. The flexible group included the Zilver Vena or the Sinus Venous stents.

Results

Differences in Venous Clinical Severity Score (p = 0.09) and Villalta score were found (p = 0.28). Tapering (0 versus 5, p = 0.03) and bad alignment were found (0 versus 5, p = 0.03). The rigid stents showed patency rates of 80, 86 and 92% compared to 88, 96 and 98% in the flexible group.

Conclusion

Dedicated venous stents show good patency outcomes and clinical results. Tapering and bad alignment between connecting stents are more frequently seen in more rigid stents.

Patency rates, safety and clinical results of the sinus-Obliquus venous stent in the treatment of chronic ilio-femoral venous outflow obstruction - data from the Arnsberg venous registry

Background: We sought to determine the patency and clinical symptom relief following the usage of the sinus-Obliquus venous stent in the endovascular treatment of venous obstruction of the ilio-femoral track in short-term. Patients and methods: 48 patients (62 % female, mean age 57 years) with chronic unilateral post-thrombotic obstruction (PTO) and non-thrombotic iliac vein obstructive lesions (NIVL) without involvement of inferior vena cava receiving a sinus-Obliquus venous stent was included in the analysis. Clinical improvement determined by the revised venous clinical severity score (rVCSS) as well as the clinical, etiologic, anatomic and pathophysiologic score (CEAP), safety, and stent patency rates were determined at baseline and at 1, 6 and 12 months after stent placement. Ten of the 48 included patients had a venous ulceration. Results: Primary patency rates were 98 % at FU1, 94 % at FU2 and 94 % at FU3, respectively. Secondary patency was 100 % at FU1, 96 % at FU2 and remained 96 % at FU3. At 12 months, the mean rVCSS dropped from 9.0 to 4.8 points (p < 0.001) whereas the mean CEAP improved from 3.45 to 2.96 (p < 0.001). A substantial healing of ulcerations was observed in 8 of 10 patients with initial venous ulceration. There were no relevant safety concerns noticed. Conclusions: Even though long-term studies are missing, the sinus-Obliquus venous stent already showed very promising patency rates at short term, associated with substantial clinical improvement and low device-related complications in both NIVL and PTS.

Placement of closed-cell designed venous stents in a mixed cohort of patients with chronic venous outflow obstructions – short-term safety, patency, and clinical outcomes

Abstract. Background: To evaluate the performance of a closed-cell designed venous stent for the treatment of chronic ilio-femoral venous outflow obstruction (VOO) in the shortterm. Patients and methods: Safety, stent patency and clinical outcome after placement of the Vici Venous Stent® in patients with chronic ilio-femoral venous obstruction were assessed retrospectively. Stent patency was evaluated by duplex ultrasound scanning, and clinical outcome was determined using the revised Venous Clinical Severity score (rVCSS). Results: 75 patients (49 % female; median age 57 years; 82 limbs) with symptomatic significant VOO had stents placed in the ilio-femoral veins. Lower limb venous skin changes including ulcers (C-class in CEAP 4–6) were found in 31 patients (41 %). Nonthrombotic iliac vein lesions (NIVLs) and post-thrombotic obstruction (PTO) were found in 40 and 42 limbs, respectively. There were no safety issues. Cumulative primary, assisted-primary, and secondary stent patency in the entire cohort at 12 months were 94 %, 94 % and 96 %, respectively. Five limbs presented with stent occlusion. Two limbs had no intervention, 2/3 remained patent after reintervention. Clinical improvement (a decrease ≥ 2 rVCSS points) was observed in 81 %, 81 %, and 77 % of patients at 1 month, 6 months, and 12 months, respectively. There was a marked drop in the frequency of more marked pain and swelling (VCSS ≥ 2) from 62 % to 5 % and 93 % to 19 %, respectively. Four limbs had venous ulcers, three healed during the follow-up. Cumulative pri- mary stent patency at 12 months was 100 % and 87 % in patients with NIVL and PTO, respectively (p= 0.032). There was no statistical difference in clinical outcome between these subgroups. Conclusions: The Vici Venous Stent® placed in the ilio-femoral vein segment in patients with symptomatic VOO revealed no safety issues, had excellent primary patency and substantial symptom improvement. Long-term studies are needed to evaluate the durability of this stenting procedure.

Standards for recanalisation of chronic venous outflow obstructions

Abstract. Postthrombotic syndrome (PTS) is the most common complication after iliofemoral deep vein thrombosis. It reduces quality of life and increases deep vein thrombosis (DVT)-related costs. The clinical symptoms and severity of PTS may vary; the most common symptoms include edema, pain (venous claudication), hyperpigmentation, lipodermatosclerosis, and ulceration. PTS is based on the principle of outflow obstruction, which may be caused by venous hypertension and may lead to valvular damage and venous reflux or insufficiency. Recent technical developments and new stent techniques now allow recanalisation of even complex venous outflow obstructions within the iliac vein and the inferior vena cava. This manuscript gives an overview on the latest standards for venous recanalisation.

Endovascular treatment of post-thrombotic and non-thrombotic iliofemoral venous outflow obstructions with self-expanding nitinol stents

BACKGROUND

The aim of the study was to investigate venous patency and clinical outcomes for endovascular treatment of iliofemoral venous obstruction in patients with post-thrombotic syndrome (PTS) and non-thrombotic iliac vein lesion (NIVL) with dedicated self-expanding nitinol stents.

PATIENTS AND METHODS

Data were collected from the prospective Swiss Venous Stent Registry, enrolling consecutive patients with a standardized follow-up procedure since January 2008. Patency was evaluated by duplex sonography and clinical outcome by various scores including the Villalta score at baseline, three, six, and 12 months, and then annually after endovascular therapy.

RESULTS

Overall, 93 patients (64 PTS, 29 NIVL) were analysed. Mean follow-up time was 20 ± 16 (range 3-70) months. A total of 11 (12 %) patients had a stent occlusion, all of which occurred in the PTS group, and 13 (14 %) patients had a symptomatic stent stenosis. Primary patency was 79 % (95 % CI 68-87 %) at 12 months and 72 % (95 % CI 59-82 %) at 24 months. In PTS patients, primary patency at 12 months was 75 % (95 % CI 61-84 %) vs. 89 % (95 % CI 63-97 %) in NIVL patients (p = 0.10). Secondary patency at 24 months was 94 % (95 % CI 84-98 %) in PTS and 100 % in NIVL, p = 0.19). Overall, 62 (67 %) patients were free from PTS at the latest follow-up with a Villalta score < 5 points. Predictive factors for the loss of primary patency were stents placed below the inguinal ligament (OR 2.59, 95 % CI, 0.99-6.84, p = 0.05).

CONCLUSIONS

In symptomatic patients with chronic iliofemoral vein obstruction, endovascular therapy with self-expanding nitinol stents was associated with favourable patency rates and clinical improvement in the majority of patients.

Patency rates and clinical outcomes in a cohort of 200 patients treated with a dedicated venous stent

OBJECTIVE

Minimally invasive interventions by recanalization, percutaneous transluminal angioplasty, and stenting in post-thrombotic syndrome (PTS) obstructions and iliac vein compression syndrome (IVCS) have shown good results. Until recently, no dedicated venous stents were available, and stent-related issues accounted for a decrease in patency scores. The introduction of dedicated stents with more flexibility and higher radial forces could result in higher patency scores. This study focused on the outcomes of patients treated by a dedicated sinus-Venous stent (OptiMed GmbH, Ettlingen, Germany). Patency rates and clinical evaluation are described for both PTS and IVCS patients.

METHODS

A total of 200 patients treated at a tertiary university referral center were analyzed. A percutaneous procedure was performed in 103 (51%) PTS patients and 48 (24%) IVCS patients. In 49 (25%) patients, a hybrid procedure was executed. Patency rates and complications were analyzed by duplex ultrasound. Clinical improvement was scored by Venous Clinical Severity Score, Villalta scale, and venous claudication rates.

RESULTS

The mean age was 43.2 ± 14.5 (17-81) years, and 66% were female. Mean Villalta score decreased from 10.5 ± 4.2 (3-24) to 5.3 ± 3.8 (0-14) at the latest follow-up (P < .001). Venous Clinical Severity Score decreased by a total of 3 points (P < .001). At baseline, venous claudication was present in 132 patients, which subsided in 115 (87%). Overall patency scores revealed a primary patency of 68%, assisted primary patency of 83%, and secondary patency of 90% with a median follow-up of 12 (11-12) months. Of all included patients, 122 (61%) did not have a complication during follow-up; the most frequent complications were in-stent restenosis (n = 23) and occlusion (n = 25) of the stented tract.

CONCLUSIONS

Short-term clinical results using the sinus-Venous stent are comparable to previous research. Loss of stent patency due to stent-related issues like kinking or tapering is hardly ever seen in this short-term follow-up.

New Vein Compression Entities in Patients with Unexplained Leg Swelling

BACKGROUND

This retrospective study identifies often overlooked anatomical sites for nonthrombotic venous outflow obstruction (NTVO) in patients with unexplained lower extremity edema and pain.

METHODS

We reviewed the charts of 75 consecutive patients experiencing symptoms of unexplained lower extremity edema with pain that were unexplained by ultrasound, computed tomography angiography (CTA), and magnetic resonance imaging (MRI), who subsequently underwent venography in an outpatient medical office from 2010 to 2014. We categorized venograms based on the presence or absence of NTVO lesions and calculated prevalence of each at specific sites. The patients with NTVO lesions showing >50% stenosis on venography were then treated with angioplasty and/or stenting. After intervention, we documented subjective levels of pain and edema.

RESULTS

Of the 75 venograms reviewed, physicians classified 52 as normal and 23 as showing evidence of compression, including 9 with May-Thurner syndrome and 14 with anatomical compressions at previously underreported sites. These 14 compression sites occurred at the following: iliofemoral vein at the inguinal ligament region (n = 7, 50%), external iliac vein at the iliac artery bifurcation (n = 1, 7.1%), both inguinal ligament region and iliac artery bifurcation (n = 4, 28.6%), and popliteal vein at the popliteal fossa (n = 2, 14.3%). Nine of the 14 patients (64.3%) reported total or near total resolution of lower extremity pain and edema at follow-up between 1 and 7 months (mean = 5.3 ± 2 months, median = 6 months) after balloon angioplasty and/or stent. Five with failed primary interventions underwent subsequent stenting and/or angioplasty and reported total or near total resolution of pain and clinical resolution of edema.

CONCLUSIONS

This study provides evidence to broaden the disease profile of venous compression syndromes to other sites such as the hypogastric artery, inguinal ligament, and popliteal fossa. The results support previous research that suggests increased incidence of NTVO exists among patients with unexplained lower extremity edema and pain. In an effort to encourage further exploration, we developed a diagnostic algorithm to support a critical and systematic review of patients with lower extremity edema and pain that may go unexplained using traditional diagnostic measures, including ultrasound, CTA, and MRI alone.