[Application of iliac vein molding and stent implantation through the ipsilateral great saphenous vein approach in daytime treatment mode].

OBJECTIVE: To explore the feasibility and recent efficacy of iliac vein molding and stenting in daytime treatment mode in patients with iliac vein stenosis. METHODS: Medical records of iliac vein molding and stenting performed in the ipsilateral great saphenous vein approach conducted from February 2017 to March 2022 were retrospective reviewed. There were 21 cases, 6 males and 15 females. Age ranged from 37 to 79 years [(62.5 ± 10.2) years]. The stenosis in the 21 limbs simply involved the common iliac veins in 16 patients, 2 patients had the simple and external iliac veins, and both the total and external iliac veins in 3 patients. Both iliac vein molding and iliac vein stenting were performed through the ipsilateral great saphenous vein approach. The patients with simple iliac vein stenosis with great saphenous vein valve insufficiency also underwent radiofrequency closure of great saphenous vein and flexural vein sclerosis therapy simultaneously. Regular postoperative direct oral anticoagulants therapy and stress therapy were followed. All the patients were hospitalized for less than 24 h. RESULTS: All the 21 patients operations were successful (the success rate was 100%), without any intraoperative complications. Immediate postoperative complications were puncture point bleeding in 1 case. The bandage gauze was completely wet. The bleeding was stopped after 5min of recompression. All the patients were hospitalized for less than 24 h. Follow-up results: The 3-month follow-up rate after operation was 100%. Absolute effective 18 cases (18/21, 85.7%). Relatively effective(postmentation still after surgery, but with less extent) in 3 cases (3/21, 14.3%). The iliac vein stents were unobstructed, and the trunk of the great saphenous vein was well closed in the patients with great saphenous vein radiofrequency treatment. The 6-month follow-up rate after operation was 71.4%(15/21). Of these, 14 cases (14/15, 93.3%) were absolutely effective. Relatively effective(postmentation still after surgery, but with less extent) in 1 case (1/15, 6.7%). The iliac vein stents were no restenosis or obstruction, and the trunk of the great saphenous vein was well closed in the patients with great saphenous vein radiofrequency treatment. CONCLUSION: The interventional treatment technique of iliac vein stenosis is feasible in the daytime treatment mode, with clear advantages and satisfactory recent efficacy.

In vivo evaluation of safety and performance of a tapered nitinol venous stent with inclined proximal end in an ovine iliac venous model.

A tapered stent with inclined proximal end is designed for fitting the iliac anatomically. The aim of the present study was to evaluate the safety and performance of the new stent in ovine left iliac veins. The experiment was performed in 30 adult sheep, and one nitinol-based VENA-BT® iliac venous stent (KYD stent) was implanted into each animal's left common iliac vein. Follow-up in all sheep consisted of angiographic, macroscopic, and microscopic examinations at Day 0 (< 24 h), Day 30, Day 90, Day 180 and Day 360 post-stenting (six animals per each time-point). 30 healthy ~ 50 kg sheep were included in this study and randomly divided into five groups according to the follow-up timepoint. All stents were implanted successfully into the left ovine common iliac vein. No significant migration occurred at follow-up. There is no statistically significant difference between the groups (p > 0.05), indicating no serious lumen loss occurred during the follow-up period. Common iliac venous pressure was further measured and the results further indicated the lumen patency at follow-up. Histological examinations indicated that no vessel injury and wall rupture, stent damage, and luminal thrombus occurred. There was moderate inflammatory cell infiltration around the stent in Day-0 and Day-30 groups with the average inflammation score of 2.278 and 2.167, respectively. The inflammatory reaction was significantly reduced in Day-90, Day-180 and Day-360 groups and the average inflammation scores were 0.9444 (p < 0.001, Day-90 vs Day-0), 1.167 (p < 0.001, Day-180 vs Day-0) and 0.667 (p < 0.001, Day-90 vs Day-0), respectively. The microscopic examinations found that the stents were well covered by endothelial cells in all follow-up time points. The results suggested that the KYD stent is feasible and safe in animal model. Future clinical studies may be required to further evaluate its safety and efficacy.

Thrombectomy of the Profunda Femoral Vein in Iliofemoral Deep Venous Thrombosis Using an Antegrade Popliteal Approach.

PURPOSE: Residual or undertreated inflow disease is a major cause of stent occlusion following endovascular thrombectomy for iliofemoral deep venous thrombosis (DVT). The profunda femoral vein (PFV) is an important inflow vessel alongside the femoral vein but is traditionally challenging to treat via an antegrade popliteal approach. This technical note describes a novel approach for PFV clearance in iliofemoral thrombectomy via the popliteal vein. MATERIALS AND METHODS: Eight patients underwent PFV clearance as part of iliofemoral DVT thrombectomy via an antegrade popliteal approach. In seven patients, a popliteal-profunda communicating vessel was identified permitting PFV access and thrombectomy. In one patient, a popliteal-profunda communicator was not identified and an 'up and over' approach via the femoral bifurcation from the same popliteal access was utilised. Thrombectomy was performed using the Inari ClotTriever device or Penumbra's Indigo system. RESULTS: Technical success in PFV thrombectomy was 100%. Six patients (75%) underwent stenting for an iliac stenotic lesion or May Thurner compression point. At the four-week ultrasound follow-up, the pelvic iliofemoral segment was patent in 7 patients (87.5%). The PFV was patent in 7 patients (87.5%) whereas the FV was only patent in 4 patients (50%). One patient underwent reintervention for iliofemoral stent occlusion. No PFV injury occurred and no post-procedure profunda reflux was identified. CONCLUSION: PFV clearance can be achieved via an antegrade popliteal approach in iliofemoral thrombectomy to optimise inflow, negating the need for alternative or additional venous access. PFV may maintain upstream iliofemoral vein patency even with an occluded femoral vein. LEVEL OF EVIDENCE: Level 4, Case Series.

A rare etiology of frequent ventricular ectopy: Embolic complication of a venous iliac stent to the right ventricle.

Peripheral venous stent migration is an exceedingly rare complication of endovascular stenting. In this clinical vignette, we present a case of a 74-year-old male with a history of endo-venous laser ablation therapy of the right greater saphenous vein complicated with an occlusion requiring a left iliac vein stent. The patient presented to the clinic months after the procedure with complaints of palpitations. Multimodality imaging revealed a stent that had become dislodged and was now located in the right ventricle, trapped within the tricuspid valve apparatus.

Histological Features of In-Stent Restenosis after Iliac Vein Thrombus Removal and Stent Placement in a Goat Model.

PURPOSE: To establish an animal model for in-stent restenosis (ISR) after postthrombotic iliac vein stent placement and characterize histopathological changes in tissue within the stented vein. MATERIALS AND METHODS: Iliac vein thrombosis was induced using balloon occlusion and thrombin injection in 8 male Boer goats. Mechanical thrombectomy and iliac vein stent placement were performed 3 days after thrombosis induction. Restenosis was evaluated by venography and optical coherence tomography (OCT) at 1 and 8 weeks after stent placement, and stent specimens were taken for pathological examination after the animals were euthanized. RESULTS: Thrombosis induction was successful in all 8 goats, with >80% iliac vein occlusion. After thrombus removal, OCT revealed considerable venous intimal thickening and a small number of mural thrombi. Neointimal hyperplasia with thrombus formation was observed in all goats 1 week after stent implantation; the degree of ISR was 15%-33%. At 8 weeks, the degree of ISR was 21%-32% in 3 goats, and stent occlusion was observed in 1 goat. At 1 week, the neointima predominantly consisted of fresh thrombi. At 8 weeks, proliferplastic fibrotic tissue and smooth muscle cells (SMCs) were predominant, and the stent surfaces were endothelialized in 2 of 3 goats and partially endothelialized in 1 goat. CONCLUSIONS: In the goat model, postthrombotic neointimal hyperplasia in the venous stent may result from time-dependent thrombus formation and organization, accompanied by migration and proliferation of SMCs, causing ISR. These results provide a basis to further explore the mechanism of venous ISR and promote the development of venous stents that reduce neointimal hyperplasia.

Mechanism of effect of stenting on hemodynamics at iliac vein bifurcation.

When performing stent intervention for iliac vein compression syndrome, the operator selects the appropriate stent and determines its implantation depth according to the type and severity of iliac vein stenosis in the patient. However, there is still uncertainty regarding how the structure of the stent and its implantation depth affect hemodynamics at the site of lesion. In this paper, we analyzed three commonly used stents (Vena stent from Venmedtch, Venovo from Bard, and Smart stent from Cordis) with different implantation depths (0, 10, 20 mm) using computational fluid dynamics (CFD). We focused on evaluating hemorheological parameters such as time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), etc., within one pulsatile cycle after stent implantation. The correlation between geometric parameters of the stents and hemodynamic indicators was assessed using Pearson correlation coefficient (r), which was further validated through PIV velocity measurement experiment. The results revealed that an increase in implantation depth led to a more pronounced disturbance effect on blood flow at bifurcation for densely arranged support body-type stents. This effect was particularly significant during periods of smooth blood flow. On the other hand, crown-shaped Vena stents exhibited relatively less disruption to blood flow post-implantation. Implantation depth showed a strong negative correlation with TAWSS but a strong positive correlation with OSI and RRT. These findings suggest an increased risk of thrombosis at iliac vein bifurcation following stent placement. Amongst all three tested stents, Vena Stent demonstrated more favorable periodic parameters after implantation compared to others. These results provide valuable theoretical insights into understanding contralateral circulation thrombosis associated with iliac vein stenting.

Comparative outcomes of catheter-directed thrombolysis versus AngioJet pharmacomechanical catheter-directed thrombolysis for treatment of acute iliofemoral deep vein thrombosis.

OBJECTIVE: The objective of this study was to compare the outcomes of pharmacomechanical thrombolysis and thrombectomy (PCDT) plus catheter-directed thrombolysis (CDT) vs CDT alone for the treatment of acute iliofemoral deep vein thrombosis (DVT) and summarize the clinical experience, safety outcomes, and short- and long-term efficacy. METHODS: We performed a 4-year retrospective, case-control study. A total of 95 consecutive patients with acute symptomatic iliofemoral deep vein thrombosis (DVT) with a symptom duration of ≤7 days involving the iliac and/or common femoral veins underwent endovascular interventions. The patients were divided into two groups according to their clinical indications: PCDT plus CDT vs CDT alone. Statistical analyses were used to compare the clinical characteristics and outcomes between the two groups. Additionally, the patients were followed up for 3 to 36 months after treatment, and the proportions of post-thrombotic syndrome (PTS) and moderate to severe PTS were analyzed using the Kaplan-Meier survival method. RESULTS: A total of 95 consecutive patients were analyzed in this retrospective study, of whom, 51 underwent CDT alone and 44 underwent PCDT plus CDT. Between the two groups, in terms of immediate-term efficacy and safety, significant differences were found in the catheter retention time (60.64 ± 12.04 hours vs 19.42 ± 4.04 hours; P < .001), dosages of urokinase required (5.82 ± 0.81 million units vs 1.80 ± 0.64 million units; P < .001), the detumescence rate at 24 hours postoperatively (48.46% ± 8.62% vs 76.79% ± 7.98%; P = .026), the descent velocity of D-dimer per day (2266.28 ± 1358.26 µg/L/D vs 3842.34 ± 2048.02 µg/L/D; P = .018), total hospitalization stay (6.2 ± 1.40 days vs 3.8 ± 0.70 days; P = .024), number of postoperative angiograms (2.4 ± 0.80 vs 1.2 ± 0.30; P = .042), and grade III venous patency (>95% lysis: 54.5% vs 68.6%; P = .047). Furthermore, during the follow-up period, significant differences were found in the incidence of PTS (Villalta scale ≥5 or a venous ulcer: 47.0% vs 27.7%; P = .037), and the incidence proportion of moderate to severe PTS at 12 months (15.7% vs 4.5%; P = .024) and 24 months (35.3% vs 11.4%; P = .016). CONCLUSIONS: Compared with CDT alone, in the iliofemoral DVT subgroup with a symptom duration of ≤7 days, PCDT plus CDT could significantly relieve early leg symptoms, shorten the hospitalization stay, reduce bleeding complications, promote long-term venous patency, and decrease the occurrence of PTS and the incidence proportion of moderate to severe PTS. Thus, the short- and long-term outcomes both support the superiority of PCDT plus CDT vs CDT in this subgroup.

An Evaluation of the Duration of Oral Anticoagulant Use Among Patients Undergoing Endovascular Treatment of Nonthrombotic Iliac Vein Lesions.

BACKGROUND: This study aimed to compare clinical outcomes associated with the duration of postoperative direct oral anticoagulant (DOACs) therapy in patients with nonthrombotic iliac vein lesions. METHODS: We retrospectively analyzed 176 consecutive patients who underwent stenting for nonthrombotic iliac vein lesions between March 2018 and December 2021. In total, 99 and 77 patients were discharged on a 3-month and >3-month regimen of DOAC therapy, respectively. The primary cumulative endpoint was a composite of thrombotic complications, bleeding complications, primary patency, primary-assisted patency, and secondary patency within 1 year. RESULTS: Patients undergoing 3-month and >3-month DOAC therapy were similar in age, sex, lesion site, symptoms, and average stent diameter and length. Upon multivariate analysis, the primary cumulative endpoint did not differ between the 2 groups (hazard ratio [HR]: 1.18; 95% confidence interval [CI]: 0.42-3.30; P = 0.76). Moreover, the primary patency at 1 year did not differ between the groups (HR: 1.50; 95% CI: 0.14-16.54; P = 0.74). Furthermore, there were no discernible differences in the secondary endpoints of bleeding complications (HR: 0.66; 95% CI: 0.22-1.96; P = 0.45) or thrombotic complications (HR: 1.79; 95% CI: 0.55-5.80; P = 0.34) between the groups. CONCLUSIONS: The 3-month regimen of DOAC therapy showed a similar risk of postoperative thrombosis and bleeding when compared to longer DOAC therapy durations over the course of 1 year following endovascular intervention. This could be a preferred option for patients with a higher estimated bleeding risk after venous stenting.

Coagulation-monitored, dose-adjusted catheter-directed thrombolysis or pharmaco-mechanical thrombus removal in deep vein thrombosis.

Background: Pharmaco-mechanical thrombectomy (PMT) and catheter-directed thrombolysis (CDT) are therapeutic options for selected patients with acute deep vein thrombosis (DVT) to prevent post-thrombotic syndrome (PTS). Patients and methods: We aimed to describe the clinical characteristics and outcomes of 159 patients with symptomatic iliofemoral DVT undergoing PMT alone, CDT alone, or CDT followed by PMT (bail-out) in the Swiss Venous Stent Registry. The primary outcome was the incidence of peri-interventional major and minor bleeding complications (ISTH criteria). Secondary outcomes included the incidence of PTS and stent patency after 3 years. Results: Mean age was 49±20 years and 58% were women. DVT involved the iliac veins in 99% of patients, whereas 53% had an underlying iliac vein compression. PMT alone was used in 40 patients, CDT alone in 77, and 42 received initial CDT followed by bail-out PMT due to insufficient thrombus clearance. Single-session PMT was the preferred approach in patients with iliac vein compression, patent popliteal vein, and absence of IVC thrombus. Patients treated with PMT alone received a lower r-tPA dose (median 10 mg, IQR 10-10) vs. those treated with CDT (20 mg, IQR 10-30). The rate of peri-interventional major bleeding was 0%, 1%, and 2%, whereas that of minor bleeding was 0%, 1%, and 12%, respectively, all occurring during CDT. After 3 years, PTS occurred in 6%, 9%, and 7% of patients, respectively. The primary stent patency rate was 95%, 88%, and 83%, respectively. Conclusions: The use of PMT and CDT for iliofemoral DVT was overall safe and resulted in high long-term patency and treatment success. Given the less severe presentation of DVT, single-session PMT appeared to be characterized by numerically better primary patency and lower perioperative bleeding event rates than CDT.

Endovascular Thrombectomy for Acute Iliofemoral Deep Venous Thrombosis Through a Jugular Approach with a Rotational Device.

PURPOSE: To report the effectiveness of pharmacomechanical catheter-directed thrombolysis (PCDT) in the management of acute iliofemoral deep venous thrombosis (DVT) via the jugular vein using a slow rotation and large-tip device (SRD) in a large cohort of patients. MATERIAL AND METHODS: From 2011 to 2021, 277 patients (mean age 45 years, 59.2% women) were treated in 6 centres with PCDT for ilio-fémoral DVT. PCDT was performed via the jugular vein and consisted of one session of fragmentation-fibrinolysis, aspiration and, if needed, angioplasty with stenting. The aim of PCDT was to achieve complete clearance of the venous thrombosis and to restore iliofemoral patency. Residual thrombotic load was assessed by angiography, venous patency by duplex ultrasound and clinical effectiveness by the rate of post-thrombotic syndrome (Villalta score > 4). RESULTS: All patients were treated via the jugular vein using an SRD, and all but one were treated with fibrinolysis. Angioplasty with stenting was performed in 84.1% of patients. After the procedure, the residual thrombotic load at the ilio-fémoral region was < 10% in 96.1% of patients. The rate of major complications was 1.8% (n = 5), the rate of minor complications was 4% (n = 11), and one patient died from pulmonary embolism (0.4%) At a median follow-up of 24 months, primary and secondary iliofemoral patency was 89.6% and 95.8%, respectively. The rate of PTS was 13.8% at 12 months. CONCLUSION: PCDT via the jugular vein using an SRD is an efficient treatment for acute iliofemoral DVT and results in high long-term venous patency and low PTS rates. Level of evidence Level 4, Case series.

Clinical efficacy of ZelanteDVT™ catheter rheolytic thrombectomy in the single-session treatment of patients with subacute deep venous thrombosis.

OBJECTIVE: To evaluate the clinical efficacy and safety of novel ZelanteDVT™ catheter rheolytic thrombectomy in the single-session endovascular management of subacute deep venous thrombosis (DVT). METHODS: A retrospective study was performed on 31 patients with subacute DVT who underwent ZelanteDVT™ catheter rheolytic thrombectomy. Procedure data, associated complications, and venous patency score were recorded. The deep venous patency and post-thrombotic syndrome (PTS) rate were assessed in all patients during follow-up visits. RESULTS: After procedure, 19.4% (6/31) patients improved to grade III thrombus removal, while the remaining patients improved to grade II. Significant iliac vein compression syndrome was identified in 54.8% (17/31) patients, and 82.4% (14/17) of them received stent implantation. No serious procedure-related complications occurred. The median follow-up time was 13 months. The primary patency rate at 12 months was 83.87%, and the incidence of PTS was 19.35%. CONCLUSION: This novel rheological thrombectomy catheter seems to have a promising application prospect for single-session treatment of subacute DVT.

Spontaneous iliac vein rupture and thrombosis in patients with May-Thurner syndrome: A narrative review.

Spontaneous iliac vein rupture (SIVR) is extremely rare and can lead to serious complications, including death. Etiologies include inflammatory processes and hormonal and mechanical triggers, with concomitant May-Thurner syndrome (MTS) being a rare cause. Management can be challenging due to the difficult balance between reducing thrombotic burden and life-threatening hemorrhage that can result from aggressive anticoagulation. Furthermore, surgical interventions are associated with high mortality, making conservative management more desirable. We report a case of SIVR with retroperitoneal hematoma and concurrent MTS that was successfully managed using conservative measures. We further provide a narrative review of the current literature addressing the diagnosis, management, and outcome of SIVR focusing on cases with concurrent MTS.

RETRACTED: Australian and New Zealand Society for Vascular Surgery clinical practice guidelines on venous outflow Obstruction of the femoral-iliocaval veins.

BACKGROUND: The overall goal of this report is to provide a high-level, practical approach to managing venous outflow obstruction (VOO) in Australia and New Zealand. METHODS: A group of vascular surgeons from the Australian and New Zealand Society for Vascular Surgery with specific interest, training, and experience in the management of VOO were surveyed to assess current local practice. The results were analyzed and areas of disagreement identified. Following this, the group performed a literature review of consensus guidelines published by leading international organizations focused on the management of chronic venous disease, namely the Society for Vascular Surgery, American Venous Forum, European Society for Vascular Surgery, American Vein and Lymphatic Society, Cardiovascular and Interventional Radiology Society of Europe, and American Heart Association. These guidelines were compared against the consensus statements obtained through the surveys to determine how they relate to Australian and New Zealand practice. In addition, selected key studies, reviews, and meta-analyses on venous stenting were discussed and added to the document. Finally, a selection of statements with >75% agreement was voted on, and barriers to the guideline's applicability were identified. RESULTS: The document addresses two key areas: patient selection and technical aspects of venous stenting. Regarding patient selection, patients with a CEAP (Clinical-Etiologic-Anatomic-Physiologic) score of ≥3 or a venous clinical severity score for pain of ≥2, or both, and evidence of >50% stenosis on venography, computed tomography venography, magnetic resonance venography, and/or intravascular ultrasound should be considered for venous stenting (level of recommendation Ib) Patients undergoing thrombus removal for acute iliofemoral deep vein thrombosis, in whom a culprit stenotic lesion has been uncovered, should be considered for venous stenting (level of recommendation Ib). Patients with chronic pelvic pain, deep dyspareunia, postcoital pain affecting their quality of life, when other causes have been ruled out, should be considered for venous stenting (level of recommendation Ic). Asymptomatic patients should not be offered venous stenting (level of recommendation IIIc). CONCLUSIONS: Patients with deep VOO have been underdiagnosed and undertreated for decades; however, in recent years, interest from physicians and industry has grown substantially. The advent of simpler and safer treatment options has revolutionized its management, but, unfortunately, formal training for venous disease has not grown at the same rate. Simplifying the technology and training required can result in inconsistent outcomes. These guidelines are aimed at developing standards of care and will serve as an educational platform for future developments.

Recanalization of Inferior Vena Cava and Bilateral Iliac Veins 15 Years after May-Thurner Syndrome-Related Occlusion.

May-Thurner syndrome (MTS) is a relatively rare condition involving mechanical compression of a vein between an artery and a bone which may result in venous stenosis, reflux, occlusion, or deep vein thrombosis (DVT). The most common location for MTS to occur is the left iliocaval confluence, specifically where the left common iliac vein crosses under the right common iliac artery and becomes compressed against a vertebral body. Our case represents a unique presentation of MTS where a missed diagnosis of MTS during a presentation of acute LLE DVT over 15 years ago which would later progress to chronic bilateral iliac vein occlusion and IVC obliteration. This also ultimately contributed to recurrent left lower extremity (LLE) DVT. The hypothesis for this case is that our patient had May-Thurner syndrome at the time of his original LLE DVT 15 years ago that went undiagnosed. He likely had "spillover" thrombus that occluded the right iliac venous system and resulted in IVC thrombosis at that time. What resulted was obliteration of the IVC between the iliac vein confluence and the renal vein level and bilateral iliac veins. The chronicity of the occlusion creates a uniqueness to this case as there are sparse reports of such longstanding ileo-caval occlusion being recanalized after such a prolonged duration.

Venous Clinical Severity Score has a suboptimal ability to detect improvement after iliac vein stenting across three years of follow-up.

OBJECTIVE: Venous Clinical Severity Score (VCSS) is currently the gold standard for measuring the severity of chronic venous disease, especially in patients with chronic proximal venous outflow obstruction (PVOO) secondary to non-thrombotic iliac vein lesions. Change in VCSS composite scores is often used to quantitatively measure the degree of clinical improvement after venous interventions. This study sought to assess the discriminative ability, sensitivity, and specificity of change in VCSS composites for detecting clinical improvement after iliac venous stenting. METHODS: A registry of 433 patients who underwent iliofemoral vein stenting for chronic PVOO from August 2011 to June 2021 was retrospectively analyzed. These 433 patients had follow-up exceeding 1 year after the index procedure. Change in VCSS composite and clinical assessment scores (CAS) were used to quantify improvement after venous interventions. CAS is an assessment by the operating surgeon based on patient self-reporting to assess the degree of improvement at each clinic visit compared with before the index procedure longitudinally across the treatment course of a patient. Patients are rated as worse (-1), no change (0), mildly improved (+1), significantly improved (+2), and asymptomatic/complete resolution (+3) at every follow-up visit as compared with their disease severity prior to the procedure based on patient self-report. This study defined improvement as CAS >0 and no improvement as CAS ≤0. VCSS was then compared with CAS. Receiver operative characteristic curve and area under the curve (AUC) were used to evaluate change in VCSS composite for its ability to discriminate between improvement and no improvement after intervention at each year of follow-up. RESULTS: Change in VCSS was a suboptimal measure for discriminating clinical improvement (1-year AUC, 0.764; 2-year AUC, 0.753; 3-year AUC, 0.715). Across all three time points, a change in VCSS threshold of +2.5 maximized the sensitivity and specificity of the instrument to detect clinical improvement. At 1 year, change in VCSS at this threshold was able to detect clinical improvement at a sensitivity of 74.9% and specificity of 70.0%. At 2 years, VCSS change had a sensitivity of 70.7% and specificity of 66.7%. At 3 years of follow-up, VCSS change had a sensitivity of 76.2% and specificity of 58.1%. CONCLUSIONS: Across 3 years, change in VCSS exhibited a suboptimal ability to detect clinical improvement in patients undergoing iliac vein stenting for chronic PVOO with considerable sensitivity but variable specificity at a threshold of 2.5.