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Calf pump failure (CPF) is a common concept in chronic venous disease. Dorsal vein pressures were originally used to define the pathophysiology. More recently, an abnormal ejection fraction (EF) and residual volume fraction (RVF) with air plethysmography (APG) have been substituted for its diagnosis. The relationship between reflux and calf pump function has been studied extensively. Reflux is thought to be the main cause of CPF, although other mechanisms may play a secondary role. Data mining in our dataset revealed that CPF is frequently found in nonrefluxive limbs-an unexpected finding. We analyzed the APG features of CPF in nonrefluxive limbs of a large cohort of patients investigated for chronic venous disease in our clinic. Data from refluxive limbs (control) seen over the same period was included for comparison. Venous obstructive pathology was variably present in both subsets. Iliac vein stent outcome in CPF limbs from both subsets is included. The role of obstruction in CPF is currently unknown.Records of 13,234 limbs in 8813 patients evaluated for suspected chronic venous disease over a 22-year period were analyzed. Prestent and poststent data in 406 CPF limbs (129 nonrefluxive; 277 refluxive) that underwent iliac vein stenting to correct associated stenosis are included. This is a single-center retrospective analysis of prospectively collected data. Duplex and APG data were available for included limbs. A RVF of more than 50% was defined as CPF. A reflux time of greater than 1 second elicited with automated cuffs in the erect position was defined as reflux.There were 7780 (59%) limbs with reflux and 5454 (41%) that were nonrefluxive. Supine venous pressure, an index of venous obstruction, was elevated in both subsets. The incidence of CPF was 25% in refluxive limbs and 16% in nonrefluxive limbs totaling 2790 limbs. Venous volume and venous filling index were significantly elevated (P = .0001) in refluxive limbs compared to nonrefluxive limbs. The EF was diminished (50%) in all CPF limbs except in a small fraction (n = 427 [3%]). Stent correction of iliac vein stenosis corrected CPF, normalizing the RVF in both subsets.CPF frequently occurs in nonrefluxive limbs with incidence only slightly less than in refluxive limbs. An RVF of more than 50% seems to be a practical definition of a CPF; an EF of less than 50% is associated with a RVF of greater than 50% in 97% of analyzed limbs. Prospective identification of CPF in limbs with chronic venous disease may allow more detailed investigation of its cause (preload, afterload, neuromuscular pathology or joint immobility, etc) and direct more targeted treatment than currently practiced.

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.

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

The goal of endovenous stenting is to relieve venous obstruction and reduce peripheral venous hypertension by using large caliber venous stents in the presence of adequate venous inflow and outflow for the stented conduit. The aim of this report is to describe the technical reasons and outcomes for reinterventions in a subset of patients who had a history of iliac vein stenting and were now referred to us at a specialty venous clinic for further care.From January, 2016 to December, 2021, records of all patients who were referred to us with a history of iliac vein stenting performed at an outside facility and who had a reoperation performed at our center were retrospectively analyzed.149 limbs underwent a deep venous rentervention after a failure of a trial of conservative therapy. The mean age of the sample was 57 ± 16 years. The ratio of non-thrombotic iliac vein lesions (NIVLs) to post-thrombotic lesions was 1:2.5. Majority of the patients were CEAP class C4 or higher (84%). The most common reason for reintervention was stent occlusion (74%), followed by iatrogenic stenosis (53%) and in-stent restenosis/shelving (38%). There was a trend for improvement in all clinical parameters (venous clinical severity score, visual analog scale for pain and edema grade) after the reintervention. Poor inflow was present in 70% limbs with stent occlusion. Median diameters of stented common femoral vein, external iliac vein and common iliac vein prior to reintervention were 12, 12 and 13 mm respectively. Median diameters of stented common femoral vein, external iliac vein and common iliac vein after reintervention were 14, 15 and 16 mm respectively. 88% limbs required at least one further reintervention after initial reoperation.Venous reoperations are generally infrequent and required in a small number of patients. Poor inflow appeared to be a common cause of stent occlusion. Iatrogenic stenosis is another common reason for venous reoperation and is difficult to fully rectify through current endovascular techniques and tools. Use of IVUS planimetry routinely in every deep venous intervention and thorough knowledge of the principles of venous stenting outlined in this report may help forestall the need for reoperative deep venous surgery in some cases.

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.

We have recently demonstrated in a large patient cohort that the prevalence and severity of reflux will improve in most limbs after stenting and that most limbs will not develop new-onset reflux. In the present report, we have focused on the long-term clinical outcomes associated with untreated reflux in the same patient cohort who had undergone iliofemoral venous stenting without correction of residual reflux.The clinical outcomes data from 1379 limbs treated with only iliac vein stenting without correction of superficial or deep reflux from 1997 to 2018 were analyzed (23-year follow-up period). Of the 1379 limbs, 632 (46%) had had preexisting reflux before stenting and 747 (54%) had did not. The reflux data (reflux segmental score, air plethysmography, ambulatory venous pressure) for these patients have been previously reported in detail. The subsets were compared perioperatively with each other using the following variables: grade of swelling, visual analog scale for pain score, venous clinical severity score, venous stasis dermatitis, ulceration, and quality of life measures.Both groups demonstrated improvements in the venous clinical severity score, grade of swelling, visual analog scale score, and quality of life. No differences were found in ulcer healing (5% vs 3% for limbs with and without prestent reflux, respectively) and resolution of dermatitis (6% vs 5% for limbs with and without prestent reflux, respectively) between the two groups. Of the 632 limbs with preexisting reflux, 218 (34%) had had axial reflux and 414 had had nonaxial reflux (66%). The clinical outcomes were similar between the two groups. Using a multisegment reflux score, the limbs with prestent reflux (n = 632) were divided into two groups. A segmental score of ≥3 indicated severe reflux and a score of 3 indicated moderate reflux. Of these 632 limbs, 161 (25%) had severe reflux and 471 (75%) had moderate reflux. The two groups demonstrated similar outcomes for most clinical parameters. The post-thrombotic limbs and nonthrombotic limbs also showed similar outcomes.The long-term follow-up of patients after iliac vein stenting showed that uncorrected reflux is well tolerated by most patients across most clinical measures.

The Reynolds number (RBilateral duplex ultrasound examination of 15 healthy volunteers (30 limbs) was performed before and after exercise (four flights of stairs) of the veins of the lower extremity (left and right sides) and inferior vena cava. These volunteers had been confirmed to not have any signs or symptoms of lower extremity venous disease via focused history and physical examination findings.Most of the volunteers were women (73%). Their mean age was 37 ± 12.8 years. The RThe R

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.

The extension of iliac vein stents into the common femoral vein is often required to correct stenoses found at or near the inguinal ligament. Very rarely, an extension of the iliac stent into the profunda femoris vein may be required because of severe disease at the femoral trijunction. Profunda extension of iliac vein stents is a rare but useful technique for salvage. Our experience with extensions of iliac vein stents into the profunda femoris vein is described.A search of our electronic medical records identified 20 limbs (0.75%) among a total of 2641 stented limbs (years 2006-2017) in whom the iliac vein stent was extended into the profunda femoris vein. Patients had been followed at 6 weeks, 3 months, 6 months, and yearly thereafter following the index procedure. Routine follow-up consisted of a detailed clinical evaluation, including the Venous Clinical Severity Score, visual analogue pain scale assessment, and edema grading by physical examination. Stent surveillance was performed at the follow-up visits. The iliac vein stent was declotted if needed and then extended into the profunda femoris vein at the same sitting. Antegrade access of the profunda femoris vein was preferred by direct puncture near the lesser trochanter or through a popliteal approach when a profunda-popliteal connection was present. An internal jugular access was used when an antegrade approach failed.Stent extension into the profunda was a secondary procedure after the initial iliac-common femoral vein stent failed in 17 of 20 limbs (85%). In three limbs (15%), the profunda extension was carried out at the initial iliac vein stent procedure because there was severe stenosis at the femoral confluence. One or more reinterventions after profunda extension were required in 50% of the limbs to maintain secondary patency or functionality. Fifteen of 20 limbs (75%) with profunda extensions remained patent on long-term follow-up. The median duration of secondary patency of stents that remained patent and those that occluded, and overall were 23 months, 3 months, and 10 months, respectively. Thirty percent of stents remained patent at 5 years.The extension of an iliac vein into the profunda femoris vein is a rarely required but useful procedure for stent salvage and symptom relief. Corrective reinterventions are often required but can result in long term patency extending to many years.

Iliofemoral venous stenting has become the standard of care for patients presenting with quality-of-life impairing symptoms of chronic iliofemoral venous obstruction not responding to conservative measures. This has led to an increased use of venous stenting over the last several years. However, iliofemoral venous anatomy in patients requiring such intervention remains poorly elucidated. This study attempts to fill that gap.Twenty-two consecutive patients with intravascular ultrasound examination-confirmed chronic iliofemoral venous obstruction underwent three-dimensional reconstruction of their computed tomography venogram images. Relevant angles, tortuosity (tort index-ratio between centerline length, and straight line length), lengths, and diameters were computed and analyzed. We used t tests for comparisons between the right and left sides. A P value of .05 or less was considered significant.Of the angles calculated, the median of the angles between the horizontal and common iliac vein (CIV) was 66° on the right and 60° on the left (P .01). The median inferior vena cava-CIV angle was 172° on the right and 165° on the left (P .0001). The CIV-EIV angle was 159° on the right and 151° on the L (P = .01). Overall, the median tortuosity was 1.07 on the right and 1.12 on the left (P = .007). The median centerline length of the CIV was 42mm on the right and 60mm on the left (P .0001). The median external iliac vein length was 73 mm on the right and 88 mm on the left (P .0001). The overall median iliac vein length was 220 mm on the right and 237 mm on the left (P .01). The median diameters of the inferior vena cava at the iliocaval confluence, 20, 40, and 60 mm cranial to the confluence, were 23, 20, 22, and 23 mm, respectively.Overall, the left side has steeper angles, greater tortuosity, and longer lengths than the right side. These disparities should be considered during femoroiliocaval stent construction.

Klippel-Trenaunay syndrome (KTS) is a congenital mixed mesenchymal malformation syndrome that includes varicose veins, capillary and venous malformations, lymphatic abnormalities, and hypertrophy of various connective tissue elements. The purpose of the present study was to describe the clinical characteristics and outcomes in a subset of patients with KTS in whom venous interventions, including iliofemoral venous stenting, were performed after failure of conservative therapy.A single-center retrospective data review of 34 patients with KTS who had undergone interventions for venous disease between January 2000 and December 2020 was performed.Their mean age was 38.4 ± 17.5 years (range, 12-80 years). No gender predilection was found. Of the 34 patients, 61% had had all three features of the classic triad for KTS. Varicose veins were present in all 34 patients (100%), and 30% had had a history of bleeding varicosities. Most patients (79%) had CEAP (Clinical, Etiology, Anatomy, and Pathophysiology) class ≥C4. Of the 34 patients, 30% had a history of deep vein thrombosis and/or pulmonary embolism. Factor VIII elevation was the most common thrombophilia condition (12%). The venous filling index was elevated at baseline (5.9 ± 5.1 mL/s) and did not normalize despite intervention (3.5 ± 2.3 mL/s; P = .04). The superficial venous interventions (n = 35) included endovenous laser therapy; stripping of the great saphenous vein, small saphenous vein, anterior thigh vein, or marginal vein; ultrasound-guided sclerotherapy; and stab avulsion of varicose veins. One coil embolization of a perforator vein was performed. Deep interventions (n = 19) included endovenous stenting (n = 15), popliteal vein release (n = 3), and valvuloplasty (n = 1). The venous clinical severity score had improved from 9.4 ± 4.5 to 6.2 ± 5.6 (P = .04). The visual analog scale for pain score had improved from 5.5 ± 2.7 to 2.5 ± 3.3 (P = .008). Healing of ulceration was noted in 75% of the patients. Significant improvements in the total pain (P = .04) and total psychological (P = .03) domains were noted in the 20-item chronic venous disease quality of life questionnaire.Superficial and deep venous interventions are safe and effective in patients with KTS when conservative therapy has failed. Iliofemoral venous stenting is a newer option that should be considered in the treatment of chronic deep venous obstructive disease in patients with KTS in the appropriate clinical context. An aggressive perioperative deep vein thrombosis prophylaxis protocol should be in place to reduce thromboembolic complications in these patients.

The diagnosis of chronic iliofemoral venous obstruction (CIVO) can be made with several different modalities. Intravascular ultrasound (IVUS) examination is the gold standard in the diagnosis of CIVO. However, being invasive, it should not be the initial examination to screen patients with CIVO. The aim of this report is to compare the performance of magnetic resonance venography (MRV) with IVUS examination in the diagnosis of CIVO.From January 2016 to December 2020, the records of all patients who underwent preoperative MRV and then IVUS in the evaluation of CIVO were analyzed retrospectively.There were 505 patients who were evaluated by any modality for CIVO. Of these patients, 15% (78) were evaluated by MRV. Patients who had failed a trial of conservative therapy for at least 3 to 6 months and who had disabling and lifestyle-limiting symptoms of CIVO were selected to undergo further evaluation with MRV at the treating physician's discretion. For inclusion in analysis, technically satisfactory IVUS examination and MRV data were mandatory. Data was available for 60 common iliac vein (CIV) segments and 61 external iliac vein (EIV) segments for comparative analysis after appropriate exclusions. The mean age of the patients was 56 ± 15 years. The male to female ratio was 1:2. The distribution of patients across different CEAP classes was as follows: CEAP 3, 28%; CEAP 4, 62%; CEAP 5, 2%; and CEAP 6, 8%. Bland-Altman plots of the mean difference in area between IVUS examination and MRI were 74.1% for CIV and 56.9% for EIV. The sensitivity of MRV was 93% and 100%, and the specificity was 0% and 50% for CIV and EIV, respectively. The positive predictive value was 93% and 86%; the negative predictive value was 0 and 50% for CIV and EIV, respectively. Improvement was noted in clinical parameters (Venous Clinical Severity Score, visual analog pain scale, and grade of swelling) after IVUS examination and stenting after MRV. For the Venous Clinical Severity Score, the score improved from 6.0 ± 2.7 (before the procedure) to 4 ± 2.7 (after the procedure) (P = .0001).There is dimensional disparity between MRV and IVUS examination in the diagnosis of symptomatic CIVO. MRV has a high sensitivity but low specificity when compared with IVUS examination and overestimates the severity of the stenosis in both the EIV and CIV. MRV is not a reliable diagnostic tool for iliac vein stenosis and should not be used for the definitive disposition of patients with CIVO.

Dedicated venous stents have not been used in the management of symptomatic chronic iliofemoral venous obstruction (CIVO) until recently. The Bard Venovo stent (Becton, Dickinson, and Co, Franklin Lakes, NJ) is one such stent noted to have an increased chronic outward force and radial resistive force compared with the Wallstent (Boston Scientific, Marlborough, MA). In the present study, we evaluated the outcomes following the use of the Bard Venovo stent vs a matched cohort of limbs that had undergone stenting with the Wallstent-Zenith (Z) stent (Cook Medical Inc, Bloomington, IN) composite configuration.A review of contemporaneously entered electronic medical record data for 167 patients (167 limbs) with initial iliofemoral stents placed from 2019 to 2020 for quality of life (QOL)-impairing CIVO that had failed conservative therapy was performed. The visual analog scale for pain score (score, 0-10), grade of swelling (score, 0-4), venous clinical severity score (score, 0-27), and the 20-item chronic venous insufficiency quality of life questionnaire instrument for QOL were evaluated before and after intervention to assess the effects of stenting. A Kaplan-Meier analysis was used to examine primary, primary-assisted and secondary stent patency, and analysis of variance with repeated measures was used to compare clinical outcomes.A total of 167 limbs had undergone Bard Venovo stenting (56 men and 111 women). Their median age was 61 years. The laterality was right and left in 70 and 97 limbs, respectively. Post-thrombotic syndrome was seen in 84 limbs and nonthrombotic iliac vein lesions/May-Thurner syndrome in 83 limbs. At 6 months, the venous clinical severity score had improved from 7 to 4 in the limbs with a unilateral Venovo (UV) stent and from 5 to 4 in the composite Wallstent-Z stent group (P = .9). The grade of swelling had improved from 3 to 1 in the UV group and from 3 to 1 in the composite group (P = .6), and the visual analog scale for pain score had improved from 7 to 2 in the UV group and from 5 to 0 in the composite group (P = .007). At 12 months, ulcers had healed in 53% (8 of 15) of the UV group and 56% (5 of 9) of the composite group (P = .7). The global 20-item chronic venous insufficiency quality of life questionnaire scores had improved from 58 to 28 in the UV group and from 59 to 40 in the composite group (P = .6). The cumulative primary, primary-assisted, and secondary patency at 18 months was 81%, 97%, and 98% in the UV group and 87%, 98%, and 100% in the composite group, respectively (P.4). No difference in the reintervention rates was noted between the two groups (P = .5).For patients who had undergone stenting for QOL-impairing CIVO, the results with the Bard Venovo venous stent were comparable to those with the composite Wallstent-Z stent configuration for clinical outcomes, QOL improvement, and stent patency. Further study is, however, required to confirm this improvement in the long term.

The effect of iliac vein stenting on ipsilateral limb reflux is unknown and has remained a matter of speculation. It has been suggested that the propensity for reflux might worsen when proximal stenosis is corrected. This could allow for retrograde flow with coughing and the Valsalva maneuver, stressing the valve. We examined this hypothesis by an analysis of the long-term effects of iliac vein stenting on limb reflux using a single-center, retrospective analysis of prospectively collected data.Reflux data from duplex ultrasound of 1387 limbs in 1228 patients who had undergone iliac vein stenting from 1997 to 2018 were analyzed. Of the 1387 limbs, 632 (46%) had had ipsilateral duplex ultrasound-determined valve reflux before stenting, and 747 limbs (54%) had not had reflux; data were missing for 8 limbs. Reflux status before and after stenting was available for seven individual segments for each limb in the database for analysis (total, 9653 segments). The stented patients were examined for reflux at least annually during the follow-up period (range, 1-26 years). Segmental reflux prevalence was detected using duplex ultrasound. We have referred to this as "duplex reflux" or simply "reflux." Reflux severity was graded using (1) a reflux segmental score, assigning one point each for refluxing segments in the limb; (2) air plethysmography (venous filling index [VFIPrestent duplex reflux was present in a combination of superficial, deep, and perforator segments. Reflux prevalence ranged from 7% of deep femoral segments to 51% at the popliteal segment. Post-stent reflux resolution varied from 21% at the femoral vein segment to 58% at the perforator segments. Reflux had completely resolved in 23% of the limbs. New-onset reflux was rare, with a median incidence of 7% for all segments at risk, with cumulative improvement (Kaplan-Meier curve) in reflux severity (segment score, VFILong-term follow-up of limbs after iliac vein stenting has shown that the associated ipsilateral reflux prevalence and severity will improve in most limbs over time.

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.

Background: The importance of the calf pump (the ‘peripheral heart’) in the lower limb venous circulation is well known. The ambulatory venous pressure (AMVP) is generally considered the quintessential functional test of calf pump function. However, much controversy exists on the basic hemodynamics of AMVP as well as its measurement. Recent work has helped to revise/clarify many of these controversies. Results from experimental simulations are used to illustrate key hemodynamic concepts. A multicameral model of calf pump Arnoldi popularized the notion that deep venous pressures can be monitored by inserting a needle in the dorsal foot vein (unicameral model). It has been shown recently that ambulatory venous pressures in the deep system is different from that in the dorsal foot vein and also the saphenous vein. AMVP profile in the three valved systems are different from each other (multicameral model). AMVP is traditionally monitored via % drop and also Venous refill time (VFT). Analysis of a large cohort of patients shows that VFT is more sensitive. % drop can be omitted as it is rare for it to be abnormal without concurrent abnormal VFT. AMVP is normal in venous obstruction, contradicting common belief. Ambulatory venous hypertension is a specific property of reflux, not obstruction. Supine venous pressure is elevated in obstruction but not reflux despite the suspected role of microvascular hypertension in reflux pathology. Role of calf capacitance & compliance: While severe reflux can shorten VFT, reduced calf capacitance and compliance are more important as can be shown in experimental set ups and clinical analysis. Calf Pump failure: Like the heart, the calf pump can eject all the inflow presented to it (up to 3X normal). Thus the popular concept of ‘calf pump failure’ from reflux overload has little concrete evidence to support it. Column segmentation: It is commonly assumed that valve closure results in column segmentation. It can be shown in experimental settings that collapse of the venous segment below the valve closure is necessary for column segmentation. Furthermore a reconstruction of the events surrounding column restoration makes it clear that a closed valve above the calf pump cannot reopen with the hydrostatic pressure of the restored column height below the closed valve alone. Much higher pressures generated by inflow interacting with wall tension of the infra-valvular segment is necessary to reopen the closed valve and restore flow. AMVP does not reach resting levels in experimental models till wall tension is restored to resting levels. A full blown reflux through an open valve will not transmit column pressure when the calf pump is partially collapsed. A non-invasive replacement for AMVP: Prevailing clinical practice and recent guidelines emphasize duration of reflux at the proximal saphenous, femoral and popliteal valves for assessment of reflux severity. It has been shown that these proximal valves play no significant role in column segmentation. A group of valves in the posterior tibial vein and the great saphenous vein near the ankle are the critical players in column interruption duration (CID). CID can be measured non-invasively by duplex after calf ejection by pressurized cuffs. Conclusion: AMVP has declined in clinical use as duplex identification of reflux in proximal valves has become common practice. More useful information can be obtained by using Duplex to measure CID.

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.