Editor's Choice - Management of Lower Extremity Venous Outflow Obstruction: Results of an International Delphi Consensus

OBJECTIVE

The endovascular treatment of venous obstruction has expanded significantly in recent years. Best practices for optimal patient outcomes are not well established and the evidence base is poor. The purpose of this study was to obtain consensus on management criteria for patients with lower extremity venous outflow obstruction.

METHODS

The study was conducted as a two round Delphi consensus. Statements addressed imaging, symptoms and other baseline measures, differential diagnosis, treatment algorithm, indications for stenting, inflow and outflow assessment, successful procedural outcomes, post-procedure therapies and stent surveillance, and clinical success factors. Statements were prepared by six expert physicians (round 1, 40 statements) and an expanded panel of 24 physicians (round 2, 80 statements) and sent to a pre-identified group of venous experts who met qualifying criteria. A 9 point Likert scale was used and consensus was defined as ≥ 70% of respondents rating a statement between 7 and 9 (agreement) or between 1 and 3 (disagreement). Round 1 results were used to guide rewording and splitting compound statements for greater clarity in round 2.

RESULTS

In round 1, 75 of 110 (68%) experts responded, and 91 of 121 (75%) experts responded in round 2. Round 1 achieved consensus in 32/40 (80%) statements. Consensus was not reached in the treatment algorithm section. Round 2 achieved consensus in 50/80 (62.5%). Statements reaching consensus were imaging (2/3, 66%), symptoms and other baseline measures (12/24, 50%), differential diagnosis (2/8, 25%), treatment algorithm (10/17, 59%), indications for stenting (10/10, 100%), inflow and outflow assessment (2/2, 100%), procedural outcomes (2/2, 100%), post-procedure therapies and stent surveillance, (5/7, 71%), and clinical success factors (5/7, 71%).

CONCLUSION

This study demonstrated that considerable consensus was achieved between venous experts on the optimal management of lower extremity venous outflow obstruction. There were multiple domains where consensus is lacking, highlighting important areas for further investigation and research.

Evaluation of safety and performance of a new prototype self-expandable nitinol venous stent in an ovine model

Objective

Our study was a prospective in vivo study performed on an animal model to evaluate the safety and performance of a novel venous stent designed specifically for venous applications.

Methods

The novel stents were implanted in the inferior vena cava of nine sheep. The stents were deployed with different distances between the closed cell rings to test for if the segments might migrate after being deployed at maximal distance. Three different total lengths were 9, 11, and 13 cm. After 1, 3, and 6 months, vascular injury, thrombus, neointima coverage, and stent migration were evaluated through computed tomography venography and histopathology. Imaging, histology, and integration data were analyzed for each group.

Results

All stents were deployed successfully, and all sheep survived until the time of harvesting. In all cases, the native blood vessel sections were intact. The segmented stent parts showed a differently pronounced tissue coverage, depending on the duration of the implantation.

Conclusions

The new nitinol stent is safe and feasible to implant in the venous system with a rapid surface coverage. Alteration of stent length did not affect the development of neointimal formation and did not cause migration.

Plethysmographic features of calf pump failure in chronic venous obstruction and reflux

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Oxygen Uptake Kinetics during Exercise Reveal Central and Peripheral Limitation in Patients with Ilio-Femoral Venous Obstruction

OBJECTIVE

Pulmonary oxygen uptake (V̇O₂) kinetics measured during initiation of exercise mirror energetic transition during daily activity. The aim of this study was to elucidate the pathophysiological mechanisms of exercise limitation of patients with chronic ilio-femoral vein obstruction after deep vein thrombosis by measuring V̇O₂ kinetics compared to patients with peripheral arterial disease (PAD) and healthy individuals.

METHODS

Eleven patients with ilio-femoral vein obstruction (7 man, age 20-65 yrs.), seven patients with PAD (all men, age 44-60 yrs.) and eight healthy participants (5 men, age 28-58 yrs.) were studied. Participants performed upper and lower-limb symptom-limited cardiopulmonary exercise tests on cycle ergometers; and four repeat lower-limb tests at a constant work-rate (WR) corresponding to 90% of the gas exchange threshold for determining V̇O₂ kinetics.

RESULTS

Phase I V̇O₂ amplitude in the constant WR tests (% increase over resting V̇O₂), representing the initial surge in cardiac output caused by the emptying of leg veins, was 59±19% in the ilio-femoral vein obstruction group, 73±22% in peripheral arterial disease and 85±26% in healthy participants (p=0.055 for ilio-femoral vein obstruction vs. healthy). Phase II V̇O₂ kinetics, which largely reflect the kinetics of O₂ consumption in the exercising muscles, were slower in ilio-femoral vein obstruction (tau = 42±6 s), and PAD (tau = 49±19 s), compared to healthy participants (23±4 s; p<0.01) CONCLUSIONS: Slow phase II V̇O₂ kinetics reflect a slow onset of muscular aerobic metabolism in both ilio-femoral vein obstruction and PAD. Low amplitude phase I of V̇O₂ kinetics observed in ilio-femoral vein obstruction suggests a damped cardio-dynamic phase, consistent with reduced venous return from the obstructed veins. These abnormalities of V̇O₂ kinetics may contribute to exercise intolerance in ilio-femoral vein obstruction and PAD.

Transabdominal duplex ultrasound and intravascular ultrasound planimetry measures of common iliac vein stenosis are significantly correlated in a symptomatic population

OBJECTIVE

The objectives of the present study were to determine the validity of transabdominal duplex ultrasound (TAUS) against the reference standard of intravascular ultrasound (IVUS) examinations for the detection of iliac vein obstruction (IVO).

METHODS

We analyzed the data from patients at a private vascular laboratory who had undergone IVUS investigation with an intention to treat because of symptoms of chronic venous insufficiency and a high suspicion of IVO. These patients had also previously undergone a TAUS examination at the same location. The TAUS and IVUS planimetry measures of the left common iliac vein (CIV) were correlated. These included the TAUS-measured minimum and maximum diameter and the percentage of stenosis with the IVUS-measured minimum and maximum diameter and area and the percentage of stenosis.

RESULTS

The TAUS and IVUS data from 47 patients (83% female; age, 49.3 ± 17.3 years; 64% obese) were included in the analyses. We found 89% agreement between the TAUS and IVUS findings regarding the identification of left CIV stenosis of ≥50%. The TAUS data had a positive predictive value of 95.5%. The TAUS measures of the minimum diameter and percentage of stenosis correlated significantly with the IVUS measures of the minimum diameter, minimum area, and cross-sectional area of the percentage of stenosis. The strongest correlations were between the TAUS-measured minimum diameter and IVUS-measured minimum area and percentage of the area of stenosis according to the literature-derived value. The TAUS-measured vein diameter of 8 mm equated to an IVUS cross-sectional area of 94.2 mm² (53% stenosis), and an IVUS cross-sectional area of 50% of stenosis equated to a TAUS diameter of 8.56 mm.

CONCLUSIONS

The findings from the present study support the validity of TAUS evaluation as a workup diagnostic tool for the detection of IVO. Our findings also support the use of TAUS planimetry-in particular, the CIV diameter of ≤8 mm as a threshold value-to indicate clinically relevant stenosis and trigger an IVUS investigation with an intention to treat, because this correlated with a cross-sectional area stenosis of ≥50%, as determined by IVUS examination.

Iliocaval Venous Obstruction, Cardiac Preload Reserve and Exercise Limitation

Cardiac output during exercise increases by as much as fivefold in the untrained man, and by as much as eightfold in the elite athlete. Increasing venous return is a critical but much overlooked component of the physiological response to exercise. Cardiac disorders such as constrictive pericarditis, restrictive cardiomyopathy and pulmonary hypertension are recognised to impair preload and cause exercise limitation; however, the effects of peripheral venous obstruction on cardiac function have not been well described. This manuscript will discuss how obstruction of the iliocaval venous outflow can lead to impairment in exercise tolerance, how such obstructions may be diagnosed, the potential implications of chronic obstructions on sympathetic nervous system activation, and relevance of venous compression syndromes in heart failure with preserved ejection fraction.

Venous pectoralis minor syndrome: a rare subdivision of the thoracic outlet syndrome

We analysed data of all patients who had received surgery for rare, isolated venous pectoralis minor syndrome at our tertiary institution from January 2015 to December 2018. Venous duplex scan was the preferred mode of diagnosis in all our patients. We operated on patients via a 5-6 cm deltopectoral groove incision. Ten procedures were performed on 6 patients, of whom 5 were female. The median age was 23 years (range 17-33 years). Three patients (2 female, 1 male) with bilateral pectoralis minor syndrome had separate procedures performed over a course of a few weeks. The median operating time was 22 min (range 15-95 min). Median blood loss was 20 ml (range 5-410 ml). The median hospital stay was 2 days (range 1-5 days). There was one complication in the form of a recurrence on the right side in a patient who had bilateral pectoralis minor syndrome. No other morbidities were recorded. Nine of 10 procedures (90%) were classified by patients as being satisfactory, where symptoms had partially or completely resolved. Our experience emphasizes the need for a systematic search and to maintain a high index of suspicion for venous pectoralis minor syndrome in all patients complaining of painful symptoms related to thoracic outlet syndrome. The deltopectoral groove approach is a simple and straightforward incision with a gentle learning curve.

Lumbosacral exostosis as a rare cause of iliac vein compression and significant limb swelling

A 67-year-old woman presented to our vein clinic for chronic left lower extremity edema, pain, and varicosities. After failed conservative management, a computed tomography scan revealed central venous stenosis secondary to compression of the left common iliac vein by a large osteophyte along the anterolateral aspect of the L5-S1 disk space. An anterior osteophytectomy was performed, followed by iliac venous stenting at a 1-month interval. The patient had resolution of symptoms and remains symptom free at 15 months of follow-up. This report describes a spinal exostosis causing symptomatic venous compression successfully relieved by surgical decompression.

Phlegmasia cerulea dolens secondary to an aortoiliac aneurysm

Phlegmasia cerulea dolens is an uncommon entity. We present a case of phlegmasia cerulea dolens secondary to an aortoiliac aneurysm that compressed the common iliac vein. Catheter-directed thrombolysis was not considered to be a suitable option, because the patient needed an urgent fasciotomy. The aneurysm was treated with a bifurcated stent graft and the thrombosed veins were opened with pharmacomechanical thrombectomy and recombinant tissue plasminogen activator. The reopened iliac veins, including an aneurysmal external iliac vein, were stented and fasciotomy was performed. Pharmacomechanical thrombectomy can be performed with a low dose of recombinant tissue plasminogen activator and allows for subsequent surgery.

Upper extremity deep venous thrombosis and stenosis after implantation of pacemakers and defibrillators; A prospective study

BACKGROUND

Obstruction of the access vein following cardiac pacemaker and defibrillator implantation is a common complication. However, the exact incidence and contributing risk factors are unknown. The aim of this study is to determine the incidence and analyze the contribution of each risk factor.

METHODS

57 consecutive patients candidate for their first transvenous pacemaker, implantable cardioverter-defibrillator (ICD), or cardiac resynchronization therapy device implantation were enrolled. After implantation, venography of the ipsilateral peripheral arm was performed. Patients underwent their second venography after the follow-up period of 3 to 6 months.

RESULTS

42 patients (13 females, mean age 59.71 ± 12.33) completed the study. The followup venography showed significant venous obstruction (more than 50%) in 9 (21%) patients, but in none of the individuals, venography revealed total occlusion of the veins. Patients with obstruction had more leads in their veins (2.56 ± 0.53 vs 1.58 ± 0.71, P = 0.001). Venous obstruction was significantly more prevalent in patients with implanted cardiac resynchronization therapy device compared with an ICD or pacemaker (p = 0. 01). Age, gender, diabetes mellitus, hypertension, ischemic heart disease and antiplatelet consumption did not reveal any other contribution to the risk of thrombosis. In multivariate analysis, total lead number was a positive predictor for venous occlusion (P = 0.015, OR:19.2, and CI: 1.7-207.1).

CONCLUSION

Venous obstruction is relatively frequent after pacemaker or ICD implantation. This study also shows that pacemaker and ICD leads have a similar risk for lead-related venous obstruction. However, patients with multiple leads are associated with an increased risk.

Prevalence and predictor factors of severe venous obstruction after cardiovascular electronic device implantation

AIMS

Despite not being uncommon, limited evidence exists about predisposing factors for venous obstruction in patients with implantable electronic devices. We aimed to assess the prevalence of severe venous obstruction in patients with intravenous devices and identify predictor factors.

METHODS AND RESULTS

A total of 184 patients underwent venography to detect venous obstruction associated with the inserted lead. Vessel obstruction was graded as venous occlusion (complete flow interruption), severe obstruction (narrowing >90%), or mild-moderate obstruction (narrowing 50-90%). Severe venous obstruction/occlusion prevalence was 11.4% (n = 21) and was always asymptomatic. Collateral circulation was found in 80.9% of patients with severe obstruction/occlusion. Twelve patients (6.5%) had 3 leads. The rates of patients with secondary prevention of sudden cardiac death as indication for implantable devices and of those of patients with 3 leads were significantly greater in the group with severe obstruction/occlusion than in the non-severe obstruction/occlusion group (respectively, P = 0.004 and P = 0.03). Logistic analysis adjusted for venous thromboembolic risk factors confirmed that secondary prevention of sudden cardiac death as indication for implantable devices [odds ratio (OR), 7.1; 95% confidence interval (CI): 1.4-35.3; P = 0.017] and the presence of 3 leads (OR, 8.5; 95% CI: 1.75-41.35; P = 0.008) were predictors of severe obstruction/occlusion.

CONCLUSION

In patients with implantable devices, severe venous obstruction prevalence is not negligible and the lack of symptoms does not exclude it. The presence of three leads and sudden cardiac death as indication for implantable devices seem to be associated with the presence of severe venous obstruction/occlusion.

Phlebosclerotic Colitis in a Healthy Young Woman

Phlebosclerotic colitis is a rare disease of intestinal ischemia and differentiating it from the typical ischemic colitis. It is caused by venous obstruction due to colonic and mesenteric venous calcification. We report a 36-year-old woman presenting with intermittent abdominal pain. Initial radiologic findings showed multiple tortuous thread-like calcifications in the region of the right side of the colon and transverse colon on plain abdominal radiographs and computed tomography images. In the colonoscopy, edematous dark-bluish colonic mucosa, sclerotic colon wall, and multiple ulcers without clear boundaries were observed from the ascending colon to the transverse colon. In the sigmoid colon only showed the edematous dark-bluish colonic mucosa, sclerotic colon wall. On the basis of these findings, we diagnosed the patient as having phlebosclerotic colitis. We report a rare case of phlebosclerotic colitis in healthy young woman.

Laser lead extraction to facilitate cardiac implantable electronic device upgrade and revision in the presence of central venous obstruction

Aims

The number of procedures involving upgrade or revision of cardiac implantable electronic devices (CIEDs) is increasing and the risks of adding additional leads are significant. Central venous occlusion in patients with pre-existing devices is often asymptomatic and optimal management of such patients in need of device revision/upgrade is not clear. We sought to assess our use of laser lead extraction in overcoming venous obstruction.

Methods and results

Patients in need of device upgrade/revision underwent pre-procedure venography to assess venous patency. In patients with venous occlusion or stenosis severe enough to preclude passage of a hydrophilic guide wire, laser lead extraction with retention of the outer sheath in the vasculature was performed with the aim of maintaining a patent channel through which new leads could be implanted. Data were recorded on a dedicated database and patient outcomes were assessed. Between July 2004 and April 2012, laser lead extractions were performed in 71 patients scheduled for device upgrade/revision who had occluded or functionally obstructed venous anatomy. New leads were successfully implanted across the obstruction in 67 (94%) cases. There were two major complications (infection) and four minor complications with no peri-procedural mortality. Device follow-up was satisfactory in 65 (92%) cases with mean follow-up up to 26 ± 19 months.

Conclusion

Laser lead extraction is a safe and effective option when managing patients with central venous obstruction in need of CIED revision or upgrade.

Experimental treatment of superior venous congestion during cardiopulmonary bypass

OBJECTIVES

Superior venous outflow obstruction affects cerebral perfusion negatively by reducing cerebral perfusion pressure (CPP). We present a randomized study designed to compare two alternative strategies to preserve the CPP during superior vena cava (SVC) congestion and cardiopulmonary bypass (CPB).

METHODS

Fourteen pigs on bi-caval CPB were subjected to 75% occlusion of the SVC flow. CPP was restored either by vasopressor treatment (VP, n = 7) or by partial relief (PR) of the congestion (n = 7). The cerebral effects of the interventions were studied for 60 min with intracranial pressure (ICP) monitoring, cerebral blood flow measurement, the near-infrared light spectroscopy tissue oxygen saturation index (StO2), arterial and venous blood gas analyses and serial measurements of the glial cell damage marker protein S100β.

RESULTS

Both strategies restored the CPP to baseline levels and no signs of severe ischaemia were observed. In the PR group, the venous and ICPs were normalized in response to the intervention, while in the VP group those parameters remained elevated throughout the experiment. The haemoglobin oxygen saturation in the sagittal sinus (SsagO2) was increased by both VP and PR, while significant improvement in the StO2 was observed only in the PR group. The S100β concentrations were similar in the two groups.

CONCLUSIONS

Experimental SVC obstruction during CPB may reduce the CPP, resulting in impaired cerebral perfusion. Both vasopressor treatment and improved venous drainage can, in the short term, individually restore the CPP during these circumstances.

Management of venous stenosis in living donor liver transplant recipients

AIM: To retrospectively evaluate the management and outcome of venous obstruction after living donor liver transplantation (LDLT).

METHODS: From February 1999 to May 2009, 1 intraoperative hepatic vein (HV) tension induced HV obstruction and 5 postoperative HV anastomotic stenosis occurred in 6 adult male LDLT recipients. Postoperative portal vein (PV) anastomotic stenosis occurred in 1 pediatric left lobe LDLT. Patients ranged in age from 9 to 56 years (median, 44 years). An air balloon was used to correct the intraoperative HV tension. Emergent surgical reoperation, transjugular HV balloon dilatation with stent placement and transfemoral venous HV balloon dilatation was performed for HV stenosis on days 3, 15, 50, 55, and 270 after LDLT, respectively. Balloon dilatation followed with stent placement via superior mesenteric vein was performed for the pediatric PV stenosis 168 d after LDLT.

RESULTS: The intraoperative HV tension was corrected with an air balloon. The recipient who underwent emergent reoperation for hepatic stenosis died of hemorrhagic shock and renal failure 2 d later. HV balloon dilatation via the transjugular and transfemoral venous approach was technically successful in all patients. The patient with early-onset HV stenosis receiving transjugular balloon dilatation and stent placement on the 15th postoperative day left hospital 1 wk later and disappeared, while the patient receiving the same interventional procedures on the 50th postoperative day died of graft failure and renal failure 2 wk later. Two patients with late-onset HV stenosis receiving balloon dilatation have survived for 8 and 4 mo without recurrent stenosis and ascites, respectively. Balloon dilatation and stent placement via the superior mesenteric venous approach was technically successful in the pediatric left lobe LDLT, and this patient has survived for 9 mo without recurrent PV stenosis and ascites.

CONCLUSION: Intraoperative balloon placement, emergent reoperation, proper interventional balloon dilatation and stent placement can be effective as a way to manage hepatic and PV stenosis during and after LDLT.