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Background Leg swelling in patients with various central neuromuscular disorders is a common clinical scenario and can lead to significant morbidity. The aim of the present study was to evaluate a subset of patients with central neuromuscular disorders who had undergone iliofemoral venous stenting at a specialty venous clinic at a tertiary care hospital. Methods From January 2000 to December 2020, the medical records of all patients with a known central neuromuscular disorder who had undergone iliofemoral venous stenting for chronic iliofemoral venous obstruction were retrospectively analyzed. Results A total of 42 patients (45 limbs) with central neuromuscular disorders had undergone iliofemoral stenting after failure of a trial of conservative therapy. The central neuromuscular disorders included Parkinson disease (n = 20 limbs), multiple sclerosis (n = 15 limbs), and other neuromuscular conditions (n = 10 limbs). The mean age of the sample was 59 ± 14 years. The ratio of post-thrombotic to nonthrombotic iliac vein lesions was 3:1. Most of the patients had had CEAP (clinical, etiologic, anatomic, pathophysiologic) class ≥C4 (64.4%); 25 limbs had a history of venous thromboembolism (56%). A trend was seen toward improvement in all clinical parameters measured (venous clinical severity score, visual analog scale for pain score, and edema grade) after stenting. An ulcer healing rate of ≤90% was noted after stenting. Of the 45 limbs, 24 had required some form of reintervention (53%) after initial stent placement. Conclusions Venous intervention in the form of endovenous stenting was associated with improvement in the clinical parameters for patients with central neuromuscular disorders. However, these patients should be counseled regarding the relatively higher rate of reinterventions that might be required to correct residual or recurrent symptoms.

In-stent restenosis (ISR) and stent compression (SC) are problems encountered after stenting for chronic iliofemoral venous obstruction that are responsible for a majority of reinterventions. However, characteristics of ISR and SC, in addition to outcomes after reintervention, have not been explored in detail and represent the focus of this study.A retrospective analysis of contemporaneously entered electronic medical record data on 578 limbs/patients with initial unilateral iliofemoral venous stents placed from 2014 to 2018 was performed. ISR was estimated from stent and flow channel diameters measured using duplex ultrasound. SC was estimated from rated stent diameter and actual stent diameter on duplex ultrasound. Characteristics evaluated included onset of ISR/SC after stent placement and progression over time. Analysis was performed to evaluate risk factors for the development of ISR and SC. Outcomes after reintervention for ISR/SC were also appraised.A total of 578 limbs underwent stenting for stenotic lesions (nonthrombotic iliac vein lesion/post-thrombotic syndrome). ISR was noted in 27% of limbs on post-intervention day 1. The prevalence of ISR increased to 74% by 3 months and stabilized thereafter. SC was noted in 80% of limbs on day 1 and plateaued. Of the variables evaluated as potential risk factors for ISR, intravascular ultrasound determined stent inflow luminal area and shear rate were found to be significant. For SC, asymmetric stent sizing was a significant risk factor. Over a median follow-up of 24 months, 95 of 578 (16.4%) limbs underwent reintervention for ISR, SC, or a combination. The median time to reintervention was 11 months. There was no statistically significant difference in the degree of ISR/SC among patients who underwent reintervention vs those who did not (P.05). However, there was a statistically significant difference in the grade of swelling (P = .006) and visual analog scale pain scores (P .0001) between those who underwent reintervention and those who did not. Primary, primary assisted, and secondary patencies at 60 months were 70%, 98%, and 84% after reintervention for ISR and 70%, 99%, and 84% for SC, respectively.Although ISR and SC are both common after stenting for chronic iliofemoral venous obstruction, neither are relentlessly progressive. Indication for reintervention must be a recurrence of symptoms with impairment of quality of life and not the percentage of ISR or degree of SC. After reintervention good outcomes can be expected both in terms of clinical improvement and stent patency. Further study of the impact of shear rate on stent flow is required to help reduce the incidence of ISR.

Inferior vena cava rupture is uncommon but can occur as a result of trauma or catheterization and during venous interventions. We have described two cases of iatrogenic inferior vena cava perforation, with their successful management with bare metal stents (a composite Wallstent–Z-stent technique). This management strategy was possible owing to the unique properties of the venous system.

Objective The criterion for venous stenting in symptomatic chronic iliofemoral venous obstruction has been the arbitrary use of stenosis of ≥50%. In the present study, we evaluated the intravascular ultrasound (IVUS)-determined degree of stenosis in patients who had undergone stenting for quality of life (QOL)-impairing symptoms and assessed the utility of the 50% stenosis cutoff. Methods A retrospective review of contemporaneously entered electronic medical record data from 480 continuous patients (480 limbs) with initial iliofemoral stents placed (2014 to 2017) for symptomatic chronic iliofemoral venous obstruction impairing their QOL was performed. The IVUS-determined normal minimal luminal areas for the common femoral vein (125 mm), external iliac vein (150 mm), and common iliac vein (200 mm) were used to group limbs as having Results Of the 480 limbs, 283 and 197 were in the LGS and HGS groups, respectively. A preponderance of women, left laterality, and post-thrombotic syndrome were noted in both groups. At baseline, although no difference was found in the VAS for pain score between groups, the LGS group had a higher VCSS than did the HGS group (P = .05). The baseline median supine foot venous pressure was 15 and 14 mm Hg in the LGS and HGS groups, respectively (P = .17). At 24 months after stenting, the mean VCSS had improved from 6.3 to 4.4 (P .3). No significant differences in stent patency or reinterventions rates were found. A baseline CCVIS of ≥84.5, ≥86.9, or ≥105.3 was needed for a 30-, 40-, and 50-point improvement in most limbs after stenting. Conclusions The degree of IVUS-determined iliofemoral venous stenosis did not appear to affect the initial clinical presentation, CEAP (clinical, etiologic, anatomic, pathophysiologic) clinical class, supine foot venous pressure, clinical improvement, QOL improvement, stent patency, or reintervention rates after stenting. Patients presenting with QOL-impairing symptoms in whom conservative treatment has failed merit consideration of correction of their obstruction even if the degree of stenosis is

Minimum iliac vein caliber necessary to maintain normal peripheral venous pressure can be derived by the Poiseuille equation. Duplex was compared to intravascular ultrasound (IVUS) in the assessment of iliac vein stenosis in this single center retrospective study. Parallel IVUS and duplex caliber data for common iliac vein (CIV) and external iliac vein (EIV) in 382 limbs were separately compared. One or both segments were stenotic by IVUS criteria in 213 limbs. Neither segment was stenotic by IVUS in 22 limbs. Bland–Altman analyses and Passing–Bablok linear regressions were used. Duplex calibers were dimensionally smaller than corresponding IVUS images of CIV and EIV segments in Bland–Altman comparison by a mean of 54 mm2 and 34 mm2, respectively. Passing–Bablok regression suggested the difference was due to a systematic bias and not proportional. Duplex yields a smaller cross-sectional image of CIV and EIV compared to IVUS. Duplex is not a reliable diagnostic test for iliac vein stenosis.

The "double barrel" technique has been a popular option in reconstituting the iliac-caval confluence in bilateral stenting. It has been mostly used with the Wallstent (Boston Scientific, Marlborough, Mass). The technique, although generally trouble-free, has a unique long-term complication. One stent barrel was found to compress the other from a late developing compliance mismatch. The complication is easily missed unless an intravascular ultrasound examination is performed. A cross-fenestration between the two barrels supported by a Z stent might provide clinical relief if the double barrel extension into the vena cava is relatively short in length.

Symptoms of chronic venous insufficiency secondary to obstructive iliofemoral disease are often bilateral. The impact of iliofemoral stenting of the more symptomatic lower extremity on clinical outcomes in the less affected contralateral extremity is not clear. Such benefit, secondary to offloading of collaterals, may potentially be of the magnitude that the contralateral extremity does not require intervention.A retrospective review of contemporaneously entered electronic medical record data of 368 patients/limbs with initial unilateral iliocaval stents (240 left and 128 right) placed during a 3-year period from 2015 to 2017 was performed. Patients who underwent simultaneous bilateral stenting or had occlusive disease were excluded. Of the remainder, the impact of stenting on contralateral leg symptoms was evaluated by analyzing visual analog scale (VAS) pain score (1-10), grade of swelling (1-3), and Venous Clinical Severity Score (VCSS). The duration of any improvement and need for intervention on the contralateral side were also appraised. Kaplan-Meier analysis was used to assess stent patency after intervention, whereas paired t-tests were used to examine clinical outcomes.Of the 368 limbs that underwent stenting with a combination of a Wallstent (Boston Scientific, Marlborough, Mass) with a Z stent (Cook Medical, Bloomington, Ind) for stenotic lesions, 304 patients (89 men and 215 women) had contralateral symptoms (200 left and 104 right). The cause was post-thrombotic syndrome in 229 limbs and May-Thurner syndrome or nonthrombotic iliac vein lesion in 75 limbs. In this contralateral group, at 12 months, the VAS pain score improved from 5 to 0 (P .0001), the grade of swelling went from 3 to 1 (P .0001), and VCSS went from 5 to 3 (P .0001) after stenting of the ipsilateral side. During the median follow-up of 20 months, 15 contralateral limbs underwent stenting. Median time to stenting of the contralateral limb after ipsilateral stenting was 9 months. The median VAS pain score, grade of swelling, and VCSS in this group before stenting were 6.5, 2, and 5 compared with 0 (P .0001), 1 (P = .27), and 3 (P = .0021), respectively, in those members of the contralateral group who did not require stenting. Primary and primary assisted patencies at 12 months after contralateral stenting were 78% and 100%, respectively. There were no stent occlusions after contralateral stenting.Patients with bilateral obstructive iliofemoral venous lesions often experience improvement of the contralateral limb symptoms (95%) after stenting of the worse ipsilateral limb. Only 15 of 304 (5%) symptomatic contralateral limbs had to undergo stenting during the follow-up period because of a worsening clinical picture. Based on this, a staged approach to iliofemoral stenting in patients with bilateral symptoms focusing initially on the more symptomatic limb is suggested.

Background Wallstents (Boston Scientific, Marlborough, Mass) are most commonly used in iliac-caval stenting. Approximately 20% of stented limbs require reintervention to correct in-stent restenosis (ISR) or stent compression (SC). Corrective balloon dilation to rated stent caliber (isodilation) is not always successful. We investigated whether modest overdilation of the Wallstent by 2 to 4 mm (10%-20%) beyond the rated diameter would yield better mechanical clearance of ISR/SC, leading to a larger flow channel, improved conductance, reduction of peripheral venous pressure, and better clinical outcome. Outflow lumen caliber exponentially influences peripheral venous pressure, a key mechanism in chronic venous disease. Beyond the mechanical effects, the rationale for overdilation rests on the theory that an improvement in flow channel at the margins may yield an outsized pressure reduction and clinical improvement. Methods There were 274 previously stented limbs that underwent reinterventional balloon dilation for clearance of ISR/SC during a recent 3-year period. Isodilation to rated diameter of the stent was judged effective in 71 limbs (isodilated subset); 203 limbs (overdilated subset) for which initial isodilation was ineffective underwent overdilation of the resident Wallstent by 2 to 4 mm (10%-20%) beyond the original rated diameter. IVUS planimetry was used intraoperatively to calculate SC and ISR and their subsequent clearance in the two subsets. The dilated segments were observed by clinical and duplex ultrasound examination afterward. The two subsets were compared in the following outcome measures: intraprocedural efficacy in clearing ISR/SC and achieving target lumen caliber, subsequent clinical outcomes, duplex ultrasound caliber durability, and improvement in supine foot venous pressures. This is a single-center retrospective analysis of data contemporaneously entered into a time stamped electronic medical record system. Results The median follow-up was 18 months (range, 1-35 months). Overdilation of the stent resulted in significantly better intraoperative flow channel area improvement per intravascular ultrasound. This was reflected in significantly better clinical outcome and improvement in peripheral venous pressure in the overdilated subset. Overdilation appeared to be durable up to 20 months after intervention by duplex ultrasound monitoring. Conclusions Overdilation appears to be a useful technique to correct ISR/SC and to restore target lumen caliber during reinterventional correction of a resident iliac vein Wallstent. More durable caliber improvement, superior clinical outcome, and reduction in peripheral venous hypertension were noticed in overdilated stents compared with isodilation.

Objective The incidence of obesity has been increasing, with recent data indicating that the age-adjusted mean body mass index (BMI) is close to 30 kg/m2 in the United States. Prior studies have raised concerns for an increased incidence of chronic venous insufficiency in the obese population. We aimed to build on current knowledge by assessing the effects of BMI on the initial presentation and outcomes after intravascular ultrasound (IVUS) luminal area-guided stenting in patients presenting with quality of life (QOL)-impairing chronic iliofemoral venous obstruction (CIVO). Methods A retrospective analysis of contemporaneously entered electronic medical record data on 464 continuous patients (464 limbs) with initial iliofemoral stents (2014-2017) for QOL-impairing CIVO was performed. The characteristics evaluated and compared included the degree of iliofemoral compression, CEAP (clinical, etiologic, anatomic, pathophysiologic) clinical class, venous clinical severity score (VCSS), grade of swelling (GOS), visual analog scale (VAS) for pain score, ulcer healing, reflux (venous segmental disease score; venous filling index-90), calf pump function (ejection fraction; residual volume fraction), and quality of life (CIVIQ-20 [chronic lower limb venous insufficiency 20-item questionnaire]) for those with a BMI Results Of the 464 limbs in the study cohort, 122 were in group I and 342 in group II. The median BMI was 26.3 kg/m2 (interquartile range, 19.6-29.9 kg/m2) in group I and 38.9 kg/m2 (interquartile range, 30.0-66.9 kg/m2) in group II. The IVUS luminal area–determined degree of compression was higher in group I than in group II across the common iliac, external iliac, and common femoral segments (P Conclusions Obese patients with CIVO-impairing QOL have a lesser degree of iliofemoral venous stenosis, more severe venous hypertension, and better calf pump function than their nonobese counterparts. After stenting, no differences were found in the clinical, stent patency, or QOL-related outcomes between the two groups.

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.

Background Techniques to diagnose and treat chronic iliofemoral venous obstruction (CIVO) have continued to evolve. Intravascular ultrasound (IVUS) displays real-time cross-sectional venous anatomy and can be used to guide venous interventions. However, being invasive, it is not a suitable initial screening tool. The comparison of IVUS with other three-dimensional contrast imaging modalities is less well documented. We have provided a systematic analysis of the performance of IVUS and other three-dimensional contrast imaging modalities for the evaluation of CIVO. Methods A search of various databases, including MEDLINE, Embase, EBSCOhost, Cochrane Library, CINAHL PLUS, and Web of Science, was conducted to identify studies that had compared IVUS and at least one other multidimensional contrast imaging modality, including multiplanar venography, computed tomography venography (CTV), computed tomography angiography, or magnetic resonance venography in the evaluation of CIVO. Results A total of 2117 articles were screened. Of these, eight met the inclusion criteria. Additionally, 12 other studies were identified that had compared IVUS and single plane venography. A meaningful meta-analysis could not be conducted owing to data heterogeneity. The quality of evidence varied from very low to low. IVUS identified stenotic lesions in 0% to 30% more patients compared with multiplanar venography. The CTV and IVUS measurements correlated well with each other. The sensitivity of the two-segment CTV technique approached 97%. The specificity of CTV was 57% to 86% and varied with the venous segment. The sensitivity and specificity of magnetic resonance venography compared with IVUS was 100% and 22.7%, respectively. Conclusions Given that IVUS is considered the reference standard used to guide venous interventions in patients with CIVO, the use of venography, despite using multiple projection views, underestimates the severity and presence of venous stenosis and should not be used as the only diagnostic modality. Three-dimensional CTV is noninvasive with a high sensitivity. It can be used to screen patients who might benefit from a more invasive investigation with IVUS. CTV can also be considered for the preoperative planning of venous interventions in patients with CIVO.

Background Veins are thin-walled tubes. Their lumen is roughly circular with an aspect ratio close to 1:1 under physiologic pressures. When they collapse owing to decreased internal pressure or external compression, the aspect ratio changes. The vertical diameter is usually diminished more than the transverse, with a considerable decrease in the lumen area. The recent emergence of stent correction of many venous compression syndromes, particularly iliac vein stenosis, has brought attention to the importance of the aspect ratio, quite apart from an overall decrease in caliber. The iliac vein pressure is influenced not only by stenosis, but also intra-abdominal pressure, right atrial pressure, and collaterals. We investigated the impact of aspect ratio in an experimental model incorporating these factors. Methods Inflow was provided from a header tank at 25 mm Hg pressure into a Penrose tubing enclosed in a polyethylene cylinder pressurized (Starling pressure) to simulate intra-abdominal pressures of 5 and 10 mm Hg. The Penrose drained into an outflow tank with a pressure of 7 mm Hg, simulating right atrial pressure. Stenosis was simulated with a series of three-dimensional, printed plastic nozzles with caliber areas of 50, 100, and 200 mm2 and varying in aspect ratios of 1:1 to 1:4. The flow and pressure in this system was monitored with the use of overflow collaterals in some experiments. Results Free flow from the header tank through the Penrose (zero Starling pressure) with a 200 mm2 circle nozzle into the outflow tank with zero pressure resulted in flow pressure of approximately 1.5 mm Hg. Using nozzles of a smaller caliber or an increased aspect ratio resulted in an increase of flow pressures of up to approximately 3.7 mm Hg. Flow into an outflow tank of 7 mm Hg simulating right atrial pressure further increased flow pressures by approximately 7 mm Hg. The addition of Starling pressures of 5 and 10 mm Hg simulating abdominal pressure increased flow pressure even further to the 10 to 17 mm Hg range. When the Starling pressure was dominant, the additional contribution of nozzle caliber stenosis or aspect ratio reduction to the overall flow pressure ranged from 2 to 6 mm Hg. Collateral overflow varied inversely with collateral resistance. Some experiments yielded an anomalous flow/pressure phenomena known to occur in collapsible tube flows. Conclusions A decrease in the caliber or the aspect ratio of iliac vein stenosis was among several other factors that generate peripheral venous hypertension in an experimental model. Increased intra-abdominal pressure is a major influence that amplifies the pressure effects of aspect ratio or caliber reduction.

An endovascular approach has essentially replaced open surgery in the management of symptomatic chronic obstructive iliofemoral venous disease. In the last several years, such a minimally invasive approach has shifted from use of Wallstents alone to a combination of Wallstent-Z stent (composite stenting) to better deal with the iliocaval confluence. This study evaluates the clinical and stent related outcomes following use of composite stenting.A retrospective review of contemporaneously entered EMR data on 535 patients (545 limbs) with initial iliofemoral stents placed over a 4-year period from 2014 to 2017 for symptomatic chronic iliofemoral venous obstruction was performed. Patients who underwent stenting after intervention for acute deep venous thrombosis were excluded. The impact of stenting on clinical outcomes before and after the intervention were evaluated through use of the visual analog scale pain score (0-10), grade of swelling (0-4), and Venous Clinical Severity Score (0-27). Quality of life was appraised using the Chronic Venous Disease quality of life Questionnaire 20 instrument. Kaplan-Meier analysis was used to assess primary, primary assisted and secondary stent patencies, and paired and unpaired t-tests were used to examine clinical outcomes.Of the 545 limbs that underwent stenting, 183 were in men and 362 were in women. The median age was 60 years. Laterality was right in 205 limbs and left in 340 limbs. Post-thrombotic syndrome was seen in 441 limbs and nonthrombotic iliac vein lesions/May-Thurner syndrome in 104 limbs. At 24 months, visual analog scale pain score went from 5 to 2 (P .0001), grade of swelling went from 3 to 1 (P .0001), and Venous Clinical Severity Score went from 6 to 4 (P .0001). Ulcers were present in 67 limbs and had healed in 49 limbs (73%) over a median follow-up of 26 months. Global Chronic Venous Disease quality of life Questionnaire scores improved from 60 to 36 (P .0001) after stenting. Cumulative primary, primary-assisted, and secondary patencies at 60 months were 70%, 99% and 91%, respectively. Thirty limbs (5.5%) required contralateral stenting. There was only one instance (0.2%) of contralateral iliofemoral deep venous thrombosis. One hundred eleven limbs (20%) underwent reintervention, including for in-stent restenosis in 44 limbs, stent compression in 2 limbs, in-stent restenosis and stent compression in 48 limbs, and stent occlusion in 17 limbs.In patients undergoing iliofemoral venous stenting for obstructive disease, clinical improvement, quality of life improvement, and stent patencies after use of a composite stent configuration are comparable with those seen after exclusive use of Wallstents. However, the use of a composite stent configuration not only decreases the need for contralateral stenting to relieve chronic obstruction, but also decreases the incidence of contralateral iliofemoral deep venous thrombosis.

Background Phasic venous flow variation with respiration is surrounded by controversy and not well understood. The current concept assigns a major role to the “abdominal pump.” According to this model, inspiratory increases in abdominal pressure compress the vena cava, increasing its internal venous pressure and propelling blood upstream. Some have assigned a secondary role to the “thoracic pump,” with the negative intrapleural pressure aiding blood flow toward the heart. The aim of the present study was to examine the phasic changes in flow, pressure, and volume in the central veins and named tributaries. Methods Caliber area changes were measured using intravascular ultrasonography in 37 patients undergoing iliac vein stenting. The pressure was measured in 48 patients using transducer tip catheters with electronic zero calibration. Duplex ultrasound flow in the head and neck and truncal and limb veins during inspiration and expiration was measured in 15 normal volunteers. Results The caliber of the abdominal inferior vena cava had increased by 32% and its lateral pressure had decreased significantly during inspiration. Intravenous pressure in the central veins of the chest and right atrium was positive at 6 to 14 mm Hg. Negative pressures were rarely seen and then only transiently. The internal jugular vein displayed little phasic variation. The upper limb veins displayed weak inspiratory phasicity. Phase polarity was reversed in the lower limbs, with near flow stoppage during inspiration. Conclusions These observations conflict with the current notions of venous flow phasicity, which are based on push–pull pressure changes in the abdominal and thoracic veins. The paradoxical inspiratory inferior vena cava caliber increase probably explains the concurrent pressure decrease. Sustained negative pressures in the thoracic central veins and right atrium did not occur. We have proposed an alternate hypothesis for venous flow phasicity based on alternate stretching and relaxation of the mobile section of the great veins with respiratory movement.

The last several years has witnessed an increase in the diagnosis and treatment of chronic iliofemoral venous obstructive lesions. Although intravascular ultrasound (IVUS) examination has become the gold standard in the management of chronic iliofemoral venous obstruction (CIVO), it is an invasive technique. To ascertain the usefulness of noninvasive imaging technology in diagnosing and treating CIVO in symptomatic patients, we compared three-dimensional (3D) reconstructions from computed tomography venogram (CTV) with IVUS examination.Twenty-two continuous patients who underwent IVUS interrogation during intervention for CIVO formed the study cohort. Patients who had stenting performed in the setting of chronic total occlusion of the iliofemoral segment or acute iliofemoral deep venous thrombosis were excluded. All patients underwent CTV as part of their standard preoperative work up. Minimal (smallest) luminal areas of the common iliac vein (CIV), external iliac vein (EIV), common femoral vein (CFV) and the inflow channel (segment caudal to the CFV) were obtained from 3D CTV and IVUS. Centerline length measurements were obtained from 3D CTV to estimate the length of the venous stents necessary; the inflow channel luminal area was used to predict the required stent diameter. Pearson correlation was used to evaluate the association between the luminal areas obtained from the two techniques. Agreement was ascertained by use of Bland-Altman limits of agreement. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 3D CTV in predicting luminal areas was also determined. Predicted stent diameters and lengths were compared against actual stent diameters and lengths used.Pearson correlation statistic for luminal areas between 3D CTV and IVUS for the CIV was 0.89 (P .01), for EIV was 0.77 (P .01), and for CFV was 0.69 (P .01). The correlation statistic for the inflow channel luminal area was 0.90 (P .01). The sensitivity of 3D CTV in diagnosing CIVO in the CIV, EIV, and CFV were 100%, 100% and 80%, respectively. The specificity was 67%, 57%, and 86%, respectively, in the CIV, EIV, and CFV segments. The positive predictive value of 3D CTV in determining CIVO in the CIV, EIV, and CFV segments was 89%, 83%, and 92%, and the negative predictive value was 100%, 100%, and 67%, respectively. The overall accuracy was 91%, 86%, and 82% in the CIV, EIV, and CFV segments. Thus, 3D CTV is able to predict stent length within 9.5 mm of the actual stent length used. With respect to stent diameter, 3D CTV was able to predict within 2 mm of the actual stent diameter used 91% (20/22) and within 4 mm of the actual stent diameter used 100% (22/22) of the time.From a diagnostic standpoint 3D CTV does well with an overall accuracy ranging from 82% in the CFV to 91% in the CIV in predicting CIVO. It is also able to accurately predict venous stent diameter and lengths required, rendering it a good tool in the diagnosis and treatment of symptomatic CIVO.

Instent restenosis (ISR) following iliofemoral venous stenting is quite common with up to three-quarters of patients developing some degree of ISR. However, only around 16% develop recurrent symptoms impairing their quality-of-life meriting reintervention. The first line of treatment for such ISR involves the use of angioplasty balloons to recreate an adequate flow channel. At times such angioplasty alone is inadequate particularly in the presence of calcified ISR. It is in this setting that the authors decided to explore the utility of a mechanical thrombectomy device to debulk the ISR and thereby help create an adequate flow channel. The successful utilization of such a device in a patient presenting with recurrent, disabling, quality of life impairing symptoms due to ISR represents the focus of this report.

Iliac vein stenosis is a frequent pathologic process in advanced chronic venous disease. Intravascular ultrasound (IVUS) has emerged as the "gold standard" to diagnose iliac vein stenosis and to guide stent treatment. A pre-IVUS test is often obtained. Routine venography is deficient in several respects to fill this role; absence of an internal scale is a critical deficiency. Computed tomography venography (CTV) may be superior; its measurement capabilities can be used to precisely identify stenotic iliac vein caliber. Furthermore, the calibers of common iliac vein (CIV) and external iliac vein (EIV) can be individually assessed, yielding two data points instead of single-point assessment used in venography and current CTV protocols. We compared the diagnostic accuracy of the two-segment caliber method of CTV (arm vein injection of contrast material) with IVUS.In patients who underwent computed tomography assessment of iliac vein segments before IVUS examination during a 5-year period, 91 limbs were analyzed. This is a single-center, retrospective analysis of prospectively collected data. CTV images of CIV and EIV segments were compared individually and in combination with IVUS planimetry images. A caliber diameter of 16 mm for CIV and 14 mm for EIV was considered stenotic with either imaging technique. Bland-Altman plots and receiver operating characteristic curves were used.On IVUS evaluation, 84% of CIVs and 78% of EIVs were stenotic and 16% and 22% were of normal caliber. These provided IVUS positive and negative controls for CTV comparison. On CTV, at least one of the two segments (CIV or EIV) was stenotic in 90% of the limbs, about 10% to 15% higher than single-segment involvement. Mean CTV caliber difference from IVUS was +2.5% for CIV and +7.3% for EIV. On Bland-Altman plot, single-segment diagnostic sensitivity of CTV was 83% and 73% for CIV and EIV, respectively, compared with IVUS. The sensitivity increased to 97% with a positive predictive value and accuracy of 93% and 91%, respectively, when a stenotic caliber in at least one of the two segments was considered diagnostic of iliac vein stenosis. Receiver operating characteristic analysis confirmed increased accuracy of the two-segment method over single-segment assessment with an area under the curve of 0.89 (P.001).Caliber diameter of 16 mm for CIV or 14 mm for EIV on routine CTV imaging appears to correlate with IVUS caliber stenosis with good diagnostic metrics of low false positives and false negatives.

We describe our experience with the Indigo CATTM aspiration mechanical thrombectomy (AMT) system in 20 patients. A modification of the AMT technique was done in 7 patients (35%) whereby a snare was used instead of a separator. Technical success by intravascular ultrasound (IVUS) was noted in 8 patients (40%) while symptom improvement was noted in all patients prior to discharge. In 4 patients (20%), occlusion was noted on first post-operative day ultrasound; remainder demonstrated venous patency. Snare use was associated with higher technical success (85.7% versus 15.4%, p = 0.004) and less procedural blood loss (235 ± 40 cc versus 300 ± 55 cc, p = 0.04) compared to the separator.

Background Peripheral venous hypertension and microvascular injury have merged as central features of chronic venous disease. Peripheral venous pressure in the lower limb is controlled by central and peripheral mechanisms. In the current manuscript, we examine the role of peripheral factors, particularly conduit capacitance compliance, focal stenosis, and arterial inflow into the calf. Methods An experimental venous model using Penrose tubing as a venous analogue was used where the aforementioned parameters could be manipulated. Volume-pressure curves were derived in the static mode. The dynamic model attempted to simulate key pressure parameters of lower limb venous flow. Results Decreasing compliance resulted in progressive reduction of conduit capacitance affecting both bending and stretching regimens and the relative distribution between the two, rotating the volume-pressure curve toward the x-axis. Increased postcapillary (arterial) inflow increased conduit pressure. For a given inflow, pressures varied inversely to conduit caliber. Decreased compliance led to a smaller functional caliber at working pressures. Sideline capacitance with stagnant flow connected to the flow channel (simulating calf vein network) did not influence conduit pressure. Focal stenosis increased “venous pressure” if it was narrower than “optimum outflow caliber,” defined as the minimum outflow conduit caliber required to balance inflow. Percentage stenosis as traditionally calculated using adjacent lumen as denominator was uncorrelated to pressure increase. Conclusions Conduit pressure is increased with smaller native or functional (poor compliance) caliber, focal stenosis, and increased postcapillary inflow. Many of these features appear to be present in limbs clinically suspected of chronic venous disease. The importance of the geometric factor of Poiseuille equation in pressure effects of caliber reduction and collateralization is discussed.

Objective Stenting is the first-line treatment for obstructive iliocaval lesions when intervention is required. The aim of the study was to evaluate iliocaval stent patency during and after pregnancy in women of reproductive age who became pregnant after stent placement. Methods Female patients of reproductive age (18-45 years old) who underwent iliocaval stenting between May 2007 and March 2014 were identified from a three-center prospectively maintained database. Medical records were reviewed for demographics, baseline risk factors, operative data, and clinical follow-up to identify pregnancy and postpartum stent imaging. The primary end point was stent patency. Standard descriptive statistics were used. Results There were 310 women of reproductive age who received iliocaval stenting; 12 were identified to have had at least one pregnancy after stenting. The mean age was 28 ± 5 years. One patient received thrombolysis and stenting at 14 weeks of pregnancy for deep venous thrombosis (DVT) and May-Thurner syndrome, three for a previous postpartum DVT (2, 4, and 6 weeks postpartum), three for DVT before any pregnancy with a history of factor V Leiden, and the remaining five for unprovoked DVT. All stents were self-expanding with a diameter range of 14 to 16 mm. Mean time from stenting to pregnancy was 23.3 ± 28 months. All patients had patent stents during pregnancy and were prescribed therapeutic low-molecular-weight heparin by their obstetrician. One had asymptomatic left-sided stent compression 1 year after her second delivery, treated with balloon dilation. At average follow-up of 61 ± 56 months, all patients had patent stents with no ultrasound-identified structural damage or thrombosis. Conclusions Pregnancy does not negatively affect the outcomes of iliocaval stents after lysis of DVT or May-Thurner syndrome. Iliocaval stenting is not contraindicated in women of reproductive age, although close clinical and ultrasound follow-up is warranted during and after pregnancy.

Background It is generally difficult to place an iliac vein stent precisely at the iliocaval junction with venographic control or even with intravascular ultrasound guidance. Furthermore, mechanical properties of the Wallstent (Boston Scientific, Marlborough, Mass) can predispose precisely placed stents to distal displacement or stent collapse. Our center has thus advocated extending Wallstents 3 to 5 cm into the inferior vena cava to prevent complications of missed proximal lesions or stent migration. This technique has gradually been accepted, and concerns of jailing of contralateral flow were not initially recognized. We analyzed deep venous thrombosis (DVT) incidence following iliocaval stenting with two alternative techniques: (1) Wallstents with 3- to 5-cm extension into the inferior vena cava; and (2) a modified Z-stent (Cook Medical, Bloomington, Ind) technique, in which overlapping Wallstents end at the iliac confluence and caval extension is performed with a Z-stent placed at the top of the stack. The function of the Z-stent is to provide improved radial force at the iliocaval confluence and to prevent jailing of contralateral flow with larger stent interstices. Methods There were 755 limbs with consecutive Wallstent caval extensions (2006-2010) and 982 limbs with Z-stent extensions (2011-2015) analyzed for DVT incidence postoperatively. Results Demographics were similar for both groups. Mean age was 56 and 58 years in the Wallstent and Z-stent groups, respectively. There was a female predominance (Wallstent, 69%; Z-stent, 67%) and a higher incidence of left-sided disease (Wallstent, 66%; Z-stent, 56%) in both groups. There was a slightly higher incidence of post-thrombotic disease in the Z-stent subgroup (Wallstent, 53%; Z-stent, 68%). Cumulative freedom from contralateral DVT was 99% and 90% in the Z-stent and Wallstent groups, respectively (P < .001) during the 5 years following stent placement. However, all three patients with DVT contralateral to a Z-stent actually had high placement of the Wallstent across the confluence. Thus, no patients with proper Z-stent technique had a contralateral DVT. Cumulative freedom from ipsilateral DVT was 97% and 82% in the Z-stent and Wallstent groups, respectively (P < .001) during the 5 years following stent placement. The decrease in incidence of ipsilateral DVT appeared to be attributable to decreased missed distal lesions with increased operator experience and not attributable to the Z-stent itself. Conclusions Contralateral DVT incidence was significantly lower with the Z-stent modification. In addition, the Z-stent modification provides greater radial strength at the iliac-caval confluence and simplifies simultaneous or sequential bilateral stenting. Use of proper technique and intravascular ultrasound is essential to limit the incidence of ipsilateral DVT.

Chronic compartment syndrome (CCS) secondary to venous hypertension from chronic venous insufficiency is an uncommonly described entity. The measurement of high resting compartment pressure is helpful in establishing the diagnosis of CCS. The effect of deep venous intervention on compartment pressures in patients with chronic venous insufficiency is not well described. This study evaluated a subset of patients with signs and symptoms of venous disease in whom intervention (hyperdilation or new endovenous stent placement) was performed on the iliofemoral-caval venous system. The effect of the specific intervention was objectively measured by documenting preoperative and postoperative compartment pressures in the posterior superficial compartment of the calf at rest in the supine position.From January 2018 to January 2019, there were 80 limbs that underwent either hyperdilation (n = 34) or new endovenous stent placement (n = 46). All patients had measurement of compartment pressures before and after intervention with a simple needle manometer system. Values of 15 mm Hg or higher were considered indicative of CCS in the appropriate clinical context. Clinical parameters such as pain, swelling, and Venous Clinical Severity Score were measured preoperatively and postoperatively.Venous intervention in the form of hyperdilation or endovenous stent placement was associated with reduction in compartment pressure of the extremity undergoing the intervention. In the new stent subset, the compartment pressure was reduced from 17.4 (±4.9) mm Hg to 12.6 (±3.7) mm Hg (P .0001). In the hyperdilation subset, the compartment pressure was reduced from 14.9 (±4.1) mm Hg to 10.3 (±2.7) mm Hg (P .0001). There was also a significant improvement in pain, swelling, and Venous Clinical Severity Score after intervention. In patients undergoing hyperdilation, there was a significant improvement in the ejection fraction of the calf pump after intervention from 54.8% (±23.1%) to 52.1% (±18.7%; P = .009).Deep venous intervention in the form of hyperdilation or endovenous stent placement was associated with symptomatic improvement and reduction of compartment pressure of the extremity undergoing intervention.

Background Intravascular ultrasound (IVUS) examination has a higher sensitivity compared with venography in the assessment of obstructive venous disease. However, at most venous centers, both modalities continue to be used concomitantly. This study evaluated the diagnostic clinical yield of IVUS examination as a singular intraoperative investigative modality in patients in whom clinical signs and symptoms of venous disease were severe enough to merit such an examination and in whom a venogram was not performed simultaneously. Methods From January, 2013, to December, 2018, there were 31 limbs (29 patients) who only had IVUS planimetry without concomitant venogram. Clinical parameters such as pain, swelling and Venous Clinical Severity Score were measured preoperatively and postoperatively. The degree of stenosis noted on intraoperative IVUS was compared with the preoperative duplex. Incidence of complications, technical success, and clinical yield of IVUS examination were noted. Results The etiology of venous lesion was post thrombotic in the majority of patients (74%). All patients (100%) were either in Clinical, Etiologic, Anatomic, and Pathologic class C3 or higher. In all patients (100%) taken to the operating room, IVUS examination identified stenosis in at least one of the following three veins: common iliac vein, external iliac vein, and common femoral vein. Intervention was in the form of angioplasty with endovenous stenting. There was significant improvement in pain, swelling and Venous Clinical Severity Score after the intervention. Conclusions IVUS is an effective diagnostic tool that displays high quality, real-time cross-sectional anatomy during venous interventions. When used as the sole intraoperative diagnostic modality, it seems to have a high clinical yield in patients in whom signs and symptoms of venous disease are severe enough to merit intervention.

Background Ambulatory venous pressure (AMVP) measurement is considered the gold standard in evaluating calf pump function in chronic venous disease. The AMVP protocol was standardized in the 1970s with pressure monitoring through the dorsal foot vein. This technique was based on the belief that it represents calf venous pressure dynamics owing to rapid equilibration in the superficial and deep systems. This notion is subject to some doubt not only on theoretical grounds, but also owing to a lack of clinical correlation in a segment of the population with chronic venous disease. Our aims were to (1) examine if AMVP measured simultaneously through the dorsal foot vein (DFV) and the great saphenous vein (GSV) would be similar and (2) attempt to devise a noninvasive substitute via duplex measurement for the AMVP test. Methods The study was conducted in 76 limbs in 38 normal volunteers. Simultaneous AMVP measurements in DFV and GSV were made in 28 of these normal limbs. Column interruption duration (CID) after calf pump ejection was measured by monitoring duplex resumption of flow in the tibial veins and GSV after calf ejection. The return of AMVP back to baseline implies column restoration. The venous refill time therefore represents the CID via the pressure method. The pressure and duplex methods of CID were compared in the GSV. Results Key AMVP parameters (percent drop and venous refill time) significantly differed in DFV and GSV, showing a lack of pressure equilibration. CID measured by duplex in GSV was not significantly different from pressure-derived CID in the same vein. Conclusions AMVP measured through the DFV does not reflect calf pump generated pressure events in GSV. A duplex method of measuring CID in GSV and posterior tibial vein is described. Duplex-derived CID is not significantly different from pressure-derived CID in the GSV.

Peripheral venous pressure is regulated by central and peripheral mechanisms. Peripheral venous hypertension is an important pathologic component of chronic venous disease and is present in about two-third of patients with chronic venous disease. It can result from reflux, obstructive lesions or high arterial inflow. The dominant influence in patients with peripheral venous hypertension appears to be obstruction rather than reflux. Reflux can be superficial or deep or both. In about 70% of patients with reflux, valvular incompetence is present in the superficial, deep and perforator systems in some combination. In an ex vivo experimental model, conduit pressure increased with smaller native or functional caliber, focal stenosis and increased post-capillary inflow. Venous pressure in the lower limb can be measured in a variety of ways: supine resting pressure, erect resting pressure and ambulatory venous pressure. These measurements are affected by factors such as intra-abdominal pressure, intra-thoracic pressure, gravity, venoarteriolar reflux, valve reflux and venous obstruction. Venous obstruction is associated with elevated supine pressures while reflux is associated with elevated erect resting and ambulatory venous pressures. Ambulatory venous pressure reflects venous hypertension in patients with advanced venous disease. However, our investigation has shown that ambulatory venous pressure hypertension is rarely present if air plethysmography testing is negative. Consideration maybe given to the omission of the ambulatory venous pressure testing if air plethysmography testing is normal.

Background Compression has long been the mainstay of treatment in chronic venous disease (CVD). The current treatment paradigm emphasizes compression as primary treatment, awarding saphenous ablation only an optional role. The advent of endovenous interventions, such as endovenous ablation (EVA) of the saphenous vein and iliac vein stenting, has dramatically expanded therapeutic options. The relative roles of the old and newer techniques are in a state of flux and need to be redefined. Herein we provide a broad review of compression use in the context of emergent endovenous therapies. Methods Relevant key literature is selectively reviewed. It includes many past randomized controlled studies but also newer case series with a lower level of evidence that reflect evolving practice trends. Results Compression may correct local reflux, arguably improve calf hemodynamics, and control some end manifestations of CVD. Its efficacy varies widely because there is a large variability in the actual compression delivered by different products and individual bandaging techniques. Approximately 50% of ulcers recur with compression alone when it is used long term. Noncompliance with stocking use is a major issue that ranges >50% in some reports. EVA has no such compliance issues, and there is little aftercare required. EVA reduces long-term recurrence and may shorten healing time in wounds that are slow to heal with compression alone. Failure of compression can be detected as early as 2 to 6 weeks by monitoring ulcer healing metrics. Endovenous interventions yield durable clinical results in a large subset of patients in whom compression failed or could not be used. Initial costs of interventions are higher than those of compression, but long-term direct and indirect costs are likely to be substantially lower. Conclusions Compression is the appropriate initial treatment in symptomatic CVD patients, even those with ulcer. The main concern at this time is ulcer care and quick control of symptoms. However, compression is not a long-term solution, particularly in venous leg ulcers as the majority of ulcers will recur without interventional correction. The option of interventional correction should be offered early, preferably concurrently with start of compression, as delay allows progression of disease, prompts recurrence, and increases overall costs. Persisting with compression alone fruitlessly for months or years does not seem justified, given the efficacy and the minimally invasive nature of newer treatments. A treatment paradigm that emphasizes intervention side by side with compression in symptomatic CVD patients at the outset should be considered.

Objective Positive external pressure is said to decrease transmural pressure; negative pressure in the pleural cavity is widely believed to result in negative pressure in systemic chest veins. The discrepancy between erect column height and foot venous pressure has been explained on this basis. Methods These core concepts rest on static closed models that may not be appropriate. This study examined the effects of external pressures in a dynamic open model that may better reflect in vivo conditions. Flow in a Penrose drain enclosed in a chamber that could be positively or negatively pressurized was used. Input and output reservoirs with pressures in the physiological range provided flow. Flow and pressure were monitored in horizontal and erect models with modifications to suit particular experiments. Results The discrepancy between foot venous pressure and erect venous column height was shown in this experimental model to be a result of two flows in opposite directions (superior and inferior vena cavae) meeting at the zero reference level at the heart; the upper column pressure therefore does not register at the foot. Positive external pressure results in slowing of velocity with conversion to pressure. Internal and transmural pressures therefore do not decrease. Negative external pressure has only a marginal effect on flow; importantly, internal pressure does not become negative. In an experimental set-up it was shown that negative pressure in chest veins was not necessary for air embolism to occur. Conclusion Persistent negative pressure in systemic chest veins probably does not occur. The reason for the discrepant foot venous pressure is likely to be a result of dynamic flow and not negative pressure in chest veins. External positive pressure results in slowing of velocity but the transmural pressure remains largely unchanged.

Objective In most communities, the diagnosis of lymphedema in the lower extremity currently rests on clinical signs. Lymphoscintigraphy, which is objective, is performed infrequently to confirm the clinical suspicion. Given absence of a curative option for lymphedema, it is essential to obtain an accurate diagnosis before committing the patient to lifelong conservative therapy. The aim of this study was to evaluate the diagnostic accuracy of clinical signs in comparison to lymphoscintigraphy, the current objective standard. Methods Retrospective review of contemporaneously collected data of 636 consecutive limbs with swelling (318 left, 318 right) that underwent initial evaluation during a 12-month period between 2016 and 2017 was performed. All limbs were assessed for classic clinical signs of lymphedema including dorsal hump of the foot, square toes, Kaposi-Stemmer sign, and nonpitting edema. Lymphoscintigraphy was routinely performed for objective evaluation. The 436 patients who underwent the study were scored positive for lymphedema on the basis of transit time delay for the radioisotope in minutes, presence of dermal backflow, presence of collateral channels, intensity of uptake in the main channel and lymph nodes, number of nodes in the groin, and presence of popliteal nodes. Analysis was carried out to determine sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the clinical signs in determining whether a patient had lymphedema. In addition, regression analysis was carried out to evaluate the predictive value of different clinical signs in determining lymphedema. Patients with positive clinical signs but with normal findings on lymphoscintigraphy who did not have a medical cause for swelling underwent workup to determine a possible venous cause. Results Of 636 limbs with swelling, 436 (69%) underwent lymphoscintigraphy, the findings of which were normal in 178 (41%) and abnormal in 258 (59%). Of the 636 swollen limbs, 96 (15%) had clinical signs of lymphedema; 95% had dorsal hump, 37% had square toes, 32% had presence of Kaposi-Stemmer sign, and 12% had nonpitting edema. Of these 96, lymphoscintigraphy was performed on 66 (69%); 45 of 66 (68%) patients with clinical signs were positive for lymphedema; the remaining 32% were normal. Conversely, among 258 swollen limbs with abnormal findings on lymphoscintigraphy, only 45 (17%) had one or more of the clinical signs. Sensitivity and specificity of clinical signs in predicting lymphoscintigraphy-confirmed lymphedema were 17% and 88%, respectively. Overall accuracy was 47%. Of the clinical signs, only the Kaposi-Stemmer sign was a significant predictor of lymphedema (odds ratio, 7.9; P = .02). In patients with positive clinical signs but normal findings on lymphoscintigraphy, venous obstruction was the most common cause of swelling. Conclusions Clinical signs of lymphedema appear to be unreliable in making a correct diagnosis of lymphedema in one-third of patients. Conversely, in lymphoscintigraphy-confirmed lymphedema, only 17% had positive clinical signs. Of the clinical signs, only Kaposi-Stemmer sign has some predictability in determining lymphoscintigraphy-confirmed lymphedema. Venous obstruction is the most common cause of clinical signs in patients without lymphedema. Routine use of lymphoscintigraphy is recommended in patients to make an objective diagnosis of lymphedema.

Deep venous stenting has become the primary treatment option for obstructive venous disease. Precise identification and quantification of the disease as well as localization of optimal landing zones are key elements to success. Compared with venography (anteroposterior projection), intravascular ultrasound (IVUS) seems to be more sensitive in determining those parameters. This study was a blinded comparison of the relative accuracy of venography compared with IVUS in determining key parameters essential for iliac vein stenting.Between October 2013 and November 2015, there were 155 limbs (152 patients) that underwent an endovascular intervention for chronic iliofemoral vein stenosis. Venography and IVUS data were reviewed by vascular surgeons and radiologists, respectively, each blinded to the other to identify location and severity of maximal stenosis, location of iliac-caval confluence, and optimal distal landing zone. Data from venography were compared with data from IVUS. Maximal stenosis was defined as the most severe stenosis found among the four segments-common iliac vein, external iliac vein, common femoral vein, and infrarenal vena cava. IVUS was the "gold standard" for comparisons.Venography failed to identify lesion existence in 19% of limbs. The median maximal area stenosis was significantly higher with IVUS than with venography (69% vs 52%; P .0001). Furthermore, venographic correlation with IVUS for the anatomic location of maximal stenosis was present in only 32% of the limbs; venography missed the location of maximal stenosis in more than two-thirds of limbs. The iliac-caval confluence location on venography correlated with IVUS findings in only 15% of patients. In 74%, it was located higher with IVUS than with venography. The mean difference was one vertebral body. Agreement between venography and IVUS on location of the distal landing zone was only 26%. The distal landing zone defined with IVUS was lower than with venography in 64% of limbs.Compared with IVUS, venography substantially and significantly misses stenotic lesions-their location and severity; venography also misidentifies the location of the iliac-caval confluence and the distal landing zone in the majority of limbs. Those differences between IVUS and venography suggest that IVUS is the better diagnostic and procedural tool in iliac-caval stenting.

Objective May-Thurner syndrome (MTS) patients with lifestyle-limiting symptoms undergo stenting of the iliac vein for relief of compressive disease. The impact of degree of stenosis on clinical symptoms and outcomes after stenting is unknown and examined in our study. Methods Retrospective review of contemporaneously entered data of 202 patients who underwent stenting for MTS between 2005 and 2011 was performed. Classification into three groups based on luminal area obtained by intraoperative intravascular ultrasound interrogation of the involved femoroiliocaval segments was carried out. Normal luminal diameters and areas were defined as 12 mm and 125 mm2, 14 mm and 150 mm2, and 16 mm and 200 mm2 in the common femoral, external iliac, and common iliac veins, respectively. Mild ( 90%) compression groups were defined using the normal values noted previously and observed after stenting to evaluate outcomes. Kaplan-Meier analysis was done to assess primary, primary assisted, and secondary patencies. Visual analog scale for pain scores, grade of swelling, and Venous Clinical Severity Score (VCSS) before and after stenting at 6, 24, and 48 months were analyzed using paired t-test and Tukey test. Logistic regression was used to gauge the impact of multiple variables including degree of stenosis on stent reintervention. Results There were 55 patients who had mild, 87 patients who had moderate, and 60 patients who had severe iliac vein compression. Baseline demographic characteristics and comorbidities were similar across all groups. In addition, there was no statistically significant difference in median baseline visual analog scale score, grade of swelling, and VCSS among the groups. Compression was treated with angioplasty and stenting encompassing all areas of disease as determined by intravascular ultrasound. Stent technique involved use of Wallstent (Boston Scientific, Marlborough, Mass) only in 183 patients and Wallstent-Z stent (Cook Medical, Bloomington, Ind) combination in the remainder. No difference in median stent patency was noted on follow-up. Clinically, at 48 months, a statistically significant recurrence of pain, swelling, and worsening of VCSS were noted in the severe stenosis group but not in the other two groups. No variable was noted to have an impact on stent reintervention. Conclusions Severity of MTS stenosis is not a predictor of initial clinical symptoms. Long term, patients with ≥90% initial MTS stenosis experience recurrence of symptoms. The degree of iliac venous stenosis does not appear to affect stent patency. Such information will help counsel patients before intervention.

Background Microvascular venous hypertension has emerged as a central feature of chronic venous disease (CVD). Yet, the incidence and severity of peripheral venous hypertension in the clinical setting have not been reported. This is an observational study of venous hypertension in the lower limb of a large cohort of patients with suspected CVD referred to a single referral center during a 16-year period. Methods Clinical and venous laboratory test data for 8868 limbs of 5792 patients with CVD symptoms seen from 1999 to 2015 were analyzed. Subset A limbs had a mix of obstruction/reflux or neither (n = 4132). These are limbs in which duplex ultrasound reflux (yes/no) status is known. The incidence and severity of obstruction in these limbs are unknown as tests of obstruction were not routinely performed. Subset B limbs had central obstruction (n = 159). These are limbs with intravascular ultrasound-proven stenosis in the iliac veins that was corrected by stent placement. Reflux was assessed by duplex ultrasound and air plethysmography (venous filling index [VFI90]). Pressure measurements included supine venous pressure, erect venous pressure, and ambulatory venous pressure (AMVP). Pressure measurements are categorized according to Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) clinical class, reflux and obstruction with Venn distributions of prevalence. Results All pressures (supine, erect, and ambulatory) trended worse in higher CEAP clinical classes. Supine foot venous pressures were elevated in 70% and 76% of subsets A and B, respectively. A positive association between elevated supine pressures and reflux could not be shown in this study. Supine foot venous pressure did not worsen with increasing reflux in the two subsets, but erect foot venous pressure did. Elevated supine pressures were associated with obstruction in subset B. AMVP worsened in most higher reflux categories. Ambulatory venous hypertension was dominantly associated (Venn distribution) with reflux, less commonly with obstruction. Conclusions Supine venous hypertension is associated with obstruction and does not worsen with reflux. In contrast, erect foot venous pressure worsens in severe reflux categories. Ambulatory venous hypertension worsens in higher CEAP clinical classes. It worsens with increasing reflux. AMVP is dominantly associated (Venn distribution) with reflux, not obstruction.

Background Ambulatory venous pressure (AMVP) records pressure dynamics with calf exercise. Air plethysmography (APG) measures related volume detail. APG has been suggested as a noninvasive surrogate for AMVP. We examine the correlations between APG and AMVP parameters and the role of “calf pump failure” in chronic venous disease (CVD). Methods A total of 8456 limbs in 4610 patients investigated for CVD during a 20-year period were analyzed. APG and AMVP data were available in 4599 limbs for calculation of Pearson correlation coefficient; 1347 of these limbs had significant iliac vein stenosis, proven by intravascular ultrasound. Venn diagrams are used to explore overlapping incidence of APG and AMVP abnormalities. Results APG calf volume and reflux (venous volume, venous filling index) showed progressively significant deterioration with advancing Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) clinical class, anatomic extent of reflux (superficial, deep, perforator), and reflux severity (axial reflux, segmental score). Notably, calf ejection volume increased in a nearly linear fashion (R = 0.71) to venous volume such that residual volume fraction (RVF) remained normal even in the worst of these categories. AMVP too progressively deteriorated with clinical disease and reflux severity. Venous filling time was the key parameter as the pressure drop alone was abnormal in only 4% of the limbs analyzed. There was no correlation between RVF and AMVP (R = 0.22) or between AMVP and many other APG parameters. Venn distribution showed only minor overlap (30%) between AMVP and key APG abnormalities overall, but the overlap increases from 40% to 70% in advanced clinical and reflux categories. AMVP was rarely abnormal (7%) when APG was normal. Median AMVP was normal in calf pump failure categories, however defined (subnormal ejection fraction, RVF, or both). Median AMVP is normal in venous obstruction without reflux, while AMVP abnormalities are associated three to seven times more with reflux than with obstruction. Conclusions APG (venous filling index) is a useful index of reflux. Calf pump ejection is a powerful and plastic compensatory mechanism, and calf pump failure is rare. Ambulatory venous hypertension is dominantly associated with reflux and less with obstruction. AMVP too worsens with clinical and reflux severity categories. However, there is little correlation between APG and AMVP parameters as APG measures volume and AMVP measures pressure, each in its own domain, and the volume-pressure curve is nonlinear. AMVP may be omitted in routine clinical testing if APG is normal, as the yield (7%) will be very low. AMVP reflects venous hypertension, the end stage in CVD. AMVP should be used to identify such cases when APG is abnormal.

The hemodynamics of chronic venous disease differs significantly from arterial insufficiency. Often, arterial concepts are inappropriately applied to venous pathology. In some instances, such as, for example, saphenous reflux, applicable hemodynamics is unique and has no parallel in arterial practice. In this chapter, we focus on four areas of chronic venous disease: (1) quantifying saphenous reflux, (2) defining critical venous stenosis, (3) grading severity of iliac vein stenosis (“area method”), and (4) hemodynamics of venous collaterals and venous bypass.

The last 20 years has seen a significant increase in utilization of endovenous interventions in the management of chronic venous insufficiency involving the deep venous system. However, until very recently, the inventory available for such interventions was limited. With multiple stent designs in trials in the United States and in use elsewhere, endovenous stenting is primed for takeoff.

Patients with femoral vein occlusion rapidly develop collateral flow through the deep femoral vein, an embryonic collateral. In contrast, iliac vein collateralization is sparser and functionally poorer. It is not uncommon to have femoral vein occlusions associated with iliac vein obstruction, even though the femoral vein occlusion is often more readily apparent on venograms and duplex scans, whereas the iliac vein obstruction may remain occult. We examined whether percutaneous stent correction of iliac vein obstruction associated with femoral vein occlusions would yield symptomatic relief.During a 13-year period, 39 patients with femoral vein occlusions underwent stenting of associated iliac vein stenoses.Median age was 51 years (17-86 years). The male-to-female and right-to-left ratios were 1:3 and 1:2, respectively. The clinical class of the Clinical, Etiologic, Anatomic, and Pathologic (CEAP) classification was as follows: C0-2 (with pain), two of 39 (5%); C3, 19 of 39 (48%); C4, 10 of 39 (26%); C5, one of 39 (3%); and C6, seven of 39 (18%). Concurrent ablation of a refluxive saphenous vein was performed in seven of 39 (18%). Reintervention was carried out in 14 of 39 limbs (36%). Median follow-up was 26 months (1-154 months). Median iliac vein stenosis was 80% (40%-100%). Primary, primary assisted, and secondary patency rates at 2 years were 57%, 88%, and 96%, respectively. Pain grade (visual analog scale, 0-10) improved from median 5 (0-9) to 3 (0-8) after stenting (P.03); 12% were completely relieved of pain. Cumulative improvement in pain (≥ 3 of 10 on the visual analog scale) was 87% at 2 years. Median swelling (grade 0, none; grade 1, pitting; grade 2, ankle edema; grade 3, gross) improved from median 3/3 (0-3) to 2/3 (0-3) (P = .09, NS). Among 22 of 39 limbs (56%) with grade 3 swelling before stenting, seven of 22 limbs (32%) with grade 3 swelling improved (≥ 1 grade) after stent placement. In the 15 of 22 limbs (68%) with residual grade 3 swelling after stenting, subjective improvement was reported by all. Four of seven active ulcers (54%) healed. There were no obstructive sequelae after concurrent saphenous ablation. Saphenous flow in the erect position was not different from that of controls with patent femoral veins.Percutaneous stenting of associated iliac vein obstruction in symptomatic limbs with femoral vein occlusion yields satisfactory clinical relief. The saphenous vein has little collateral role in this pathologic process and can be safely ablated if it is refluxive, in line with prior observations.

The geriatric population aged 80 years and older with severe manifestations of chronic venous disease face diminishing therapeutic options. Self-applied compression is often not possible because of frailty or arthritis. Significant limb swelling diminishes mobility, affects independent living, and precipitates institutionalization. Limb ulceration and pain diminish quality of life at a time when it is paramount. Cellulitis uniquely poses septicemic risk in this age group. Family caregivers are often able to continue home care if the intensity of care can be reduced. Iliac vein stenting may have a role as it appears to be safe and effective in this advanced stage of life.Patients who had failed to respond to compression and desired palliation of continuing severe chronic venous disease symptoms were considered for iliac vein stenting. Intravascular ultrasound-guided stenting was carried out under fluoroscopy without venography in case of allergy to contrast material or decreased renal function. General anesthesia was used for better cardiopulmonary control.A total of 107 limbs (12 bilateral) were treated with iliac vein stents during a 13-year period, representing 5% of all stented limbs. Median age was 83 years (80-96 years), and 10 were ≥ 90 years; 59% were post-thrombotic. Clinical, etiologic, anatomic, and pathologic classification was as follows: C2 (with pain), 3%; C3, 32%; C4, 33%; C5, 5%; and C6, 27%. Concurrent saphenous ablation was carried out in 28% when saphenous reflux was considered ancillary and not the main disease. There was no mortality. Reintervention was required in 20% of limbs for nonocclusive stent malfunction; 2% of stents occluded. Primary and primary-assisted duplex patency rates at 5 years were 52% and 90%, respectively. The visual analog scale score of pain improved from median 4 (0-9) to 0 (0-10) after stenting (P.0001). Pain was completely relieved in 43% of limbs. Cumulative improvement in the pain score of at least 3 points was 71% at 6 years. Swelling (grade 0, none; grade 1, pitting; grade 2, ankle edema; grade 3, gross) improved from median 3 (0-3) to 1 (0-3) (P.0001). Swelling completely resolved in 25% of limbs. Cumulative improvement of at least one grade of swelling (examination) was 63% at 6 years; 70% of limbs (n = 33) with prior cellulitis were relieved of recurrence after stent placement; 61% of active ulcers healed, and 37% of patients were able to discard stockings (P.001).Iliac vein stenting appears to offer a safe and effective option in octogenarians and nonagenarians when compression fails, is difficult, or is impossible.

With increasing use of iliocaval stenting, complications have become more noticeable. Stent occlusion is one such outcome that has not been studied in detail. Characteristics of stent occlusion in addition to outcomes after recanalization are presented.An analysis of 3468 initial iliocaval stents placed during an 18-year period from 1997 to 2015 was performed. A total of 102 stent occlusions were identified, amounting to a 3% stent occlusion rate. Characteristics evaluated included onset after stent placement, techniques used for restoring patency, and their outcome. Kaplan-Meier analysis was used to assess stent patency. Regression analysis was used to evaluate risk factors for stent occlusion.Stent occlusions occurred at a median of 5.8 months after placement. The occluded stent could be reopened after a wide range of intervals, the longest being 14 years. The majority (69%) of occlusions were chronic (30 days) and the remainder (31%) were acute; 77% of the occlusions occurred in post-thrombotic limbs. The most common technique used to recanalize the acutely occluded stent was pharmacomechanical thrombectomy, whereas wire recanalization with balloon angioplasty was the technique most used for chronic occlusions. Of the 102 occluded stents, patency was achieved in 75 of 88 (84%) attempts. After successful recanalization, the median primary patency was 7 ± 1.9 months, median primary assisted patency was 7.5 ± 3.5 months, and median secondary patency was 25 ± 8.3 months. Clinically, there was improvement in the visual analog scale pain scores from a median of 3.5 to 1 (P .01), in the median grade of swelling from 2 to 1 (P .01), and in the mean Venous Clinical Severity Score from 6.4 to 3.8 (P .01) after recanalization. A 40% ulcer healing rate was noted after recanalization during a median follow-up period of 17 months. There were no significant adverse events or mortality. Regression analysis revealed stent placement for native vein occlusion as the only statistically significant predictor of stent occlusion.Stent occlusion after iliocaval stenting is a rare occurrence. Recanalization of occluded stents can be performed with minimal morbidity even months to years after occlusion with good outcomes. Long-term patency of occluded stents that were recanalized is poor compared with patency of the initially placed stent.

Endovenous stenting has supplanted open surgery as the treatment of choice for iliocaval obstruction. This review provides a brief overview of such obstructive pathology and an in-depth assessment of femoroilio- caval stenting.

Background Iliac vein stenting has emerged as a therapeutic option in chronic venous disease. The optimal stent size is unknown but should match normal caliber at a minimum. Methods Teleology: The iliac-femoral outflow caliber was measured by Duplex in healthy volunteers to determine normal caliber. Patient IVUS data: The distribution curve of IVUS planimetry data in 345 chronic venous disease limbs was analyzed: values at the right tail end of the curve should approach normal values according to distribution theory. The optimal stent size was also projected using Poiseuille equation and Young’s scaling rule. Results The optimal stent sizes in the common iliac, external iliac, and common femoral vein segments are: 16, 14, and 12 mm diameters, respectively. Conclusion Stent correction of iliac vein stenosis should aim to restore the lumen to the minimum recommended caliber during the initial procedure and later re-interventions.

The impact of presence of an IVC filter in patients undergoing stenting for symptomatic femoroiliocaval obstruction has not been explored in detail. This study attempts to fill this gap by evaluating clinical and stent-related outcomes in such patients. The incidence of deep vein thrombosis (DVT) in this setting is also analyzed.A retrospective review of contemporaneously entered EMR data on initial iliocaval stents placed in patients with an indwelling IVC filter (or placed after stenting) over a 15-year period from 2000 to 2015 was performed. A separate matched cohort that underwent initial stenting during the time frame, but which did not have an IVC filter, was utilized as the control group. Clinical outcomes were evaluated through use of the venous clinical severity score (VCSS) and visual analog scale (VAS) pain scores. Incidence of deep venous thrombosis after stenting was also reviewed in both groups. The Kaplan-Meier analysis was used to assess stent patency after intervention while t-tests were used to examine preintervention and postintervention outcomes within and in-between groups.A total of 50 limbs (40 patients) underwent placement of a femoroiliocaval stent in the setting of a preexisting (49) or post-stent (1) IVC filter [filter group]. The control group had 156 limbs (155 patients). There was no difference in VCSS, VAS pain score, or grade of swelling at baseline between the 2 groups. Over the median follow-up duration (43 months-filter group; 40 months-control group), VCSS went from 6 to 4 at 12 months (P = 0.0001) in the filter group and from 6 to 4 in the control group (P 0.0001). VAS pain scores went from 7 to 0 at 12 months (P 0.0001) in the filter group and from 5 to 0 in the control group (P0.0001). There was no significant difference in the VCSS scores or VAS pain score between the 2 groups at 12 months (P 0.05). Overall, there was a statistically significant increase in the incidence of DVT in the filter group (10%) compared to the control group (3%) [P = 0.03%]. Primary, primary assisted, and secondary patencies in the filter/control groups at 48 months were 64%/65% (P = 0.6), 100%/97% (P = 0.5), and 100%/75% (P = 0.4), respectively. Reintervention from in-stent restenosis was noted in 16% of patients in the filter group compared to 4% in the control group (P = 0.006).Patients with an IVC filter in the setting of a femoroiliocaval stent tend to have an increased rate of deep venous thrombosis on the stented side. In addition, an increased rate of reintervention secondary to in-stent restenosis was also noted. In light of this, every attempt should be made to remove the IVC filter as soon as the need for the filter no longer exists.

Reconstruction of the iliocaval system is primarily performed in symptomatic patients with obstructive chronic venous disease (CVD). Such pathology can be primary/nonthrombotic or secondary/postthrombotic. The former encompasses pathology including May–Thurner syndrome, the most common etiology of primary CVD responsible for up to a third of the disease burden. Secondary CVD is usually due to postthrombotic syndrome. Other indications for iliocaval reconstructions include malignancy involving the iliocaval territory, trauma, or radiation injury. In this review, we evaluate complex iliocaval venous reconstructions vis-a-vis indications, approaches, outcomes, and complications. Treatment of CVD is initially conservative with the use of compression stockings. A surgical route is chosen when the former fails or cannot be applied. Both open and endovascular surgical approaches exist with the latter having supplanted open approaches as the choice of intervention except in cases where an endovascular approach cannot be pursued, has failed, or in patients with malignancy where tumor removal is required. Hybrid procedures are performed occasionally when femoral vein exposure and endophlebectomy or creation of an arteriovenous fistula is required to improve inflow following surgical intervention. Endovascular reconstruction of the iliocaval system can be done with minimal morbidity and mortality with excellent long-term results. Open iliocaval revascularization has a limited role in candidates with acceptable risk and is associated with good outcomes in such patients.

Objective Percutaneous recanalization and stenting is currently the standard of care for symptomatic chronic total occlusions (CTOs) of the iliofemoral veins. CTO lesions involving the inferior vena cava (IVC) present a more complex patient subset. In this series we describe our single-center experience with endovascular recanalization of symptomatic occlusions of the IVC. Methods Patients were evaluated with duplex ultrasound imaging, venous function tests, and venography before intervention. Occluded segments were recanalized, balloon dilated, and stented. The basic stent technique modified over time to accommodate the iliocaval junction, presence of IVC filters, and lesions extending to the renal veins and atrium. Results Between November 2000 and August 2015, 71 patients (41 men [58%]) underwent IVC endovascular recanalization procedures for symptomatic chronic IVC occlusions. Patients were an average age of 51 years (range, 23-77 years). Underlying contributing factors for venous occlusion included IVC filter occlusion in 38 (54%), caval ligation/clipping in 4 (6%), and hypercoagulable disorder in 27 (38%). The technical success rate was 85% (n = 60). The proximal extent of the stents were infrarenal in 40 (67%), suprarenal in 11 (18%), or intrathoracic in 9 (15%). There was minimal perioperative morbidity (2 hematomas, 1 renal failure) and no postoperative mortality. Average follow-up was 48.0 ± 43.3 months (range, 6-172 months). Primary, primary assisted, and secondary patency rates at 60 months were 52%, 85%, and 93%, respectively. Significant improvement in pain and swelling was seen in 91% and 83%, respectively; and complete cumulative relief of pain and swelling was 66% and 41% respectively. Ulcers were present in 18 patients and healed completely without recurrence in 14 (78%) after recanalization. The Venous Clinical Severity Score was 8.4 ± 5.1 (range, 4-27) before the intervention and 3.9 ± 3.2 (range, 0-14) after the intervention ( P Conclusions Endovascular recanalization of chronic total IVC occlusions can be performed with minimal morbidity and mortality. When successful, symptoms can be substantially improved, with excellent patency.