Proximal Venous Outflow Obstruction Research Articles

Diabetes, Hypertension, and Smoking Do Not Affect Outcomes of Iliofemoral Vein Stenting for Chronic Proximal Venous Outflow Obstruction

ObjectiveDiabetes, hypertension, and smoking are well-recognized risk factors for Peripheral Artery Disease (PAD), but little is known of their impact on chronic venous insufficiency (CVI). This study evaluates these factors in patients undergoing iliac vein stenting (IVS) for CVI. MethodsA registry of 708 patients who underwent IVS from August 2011 to June 2021 was retrospectively analyzed. Symptoms were quantified using venous clinical severity score (VCSS) and CEAP classification. Both major and minor reinterventions were recorded. Logistic regression models were used to determine the unadjusted and adjusted odds ratio (OR) of any reintervention. Log-rank test was used to assess differences in reintervention-free survival. ResultsThe prevalence of hypertension was 51.1% (N = 362), diabetes was 23.0% (N = 163), and smoking was 22.2% (N = 157). Patients with diabetes (3.6 vs 3.4; P = 0.062), hypertension (3.6 vs. 3.3; P < 0.001), and smoking (3.7 vs 3.4; P = 0.003) had higher CEAP scores than those without these comorbidities. Improvement in VCSS composite scores showed no differences postoperatively (Diabetes: P = 0.513; Hypertension: P = 0.053; Smoking: P = 0.608), at 1-year follow-up (Diabetes: P = 0.666; Hypertension: P = 0.681; Smoking: P = 0.745), or at 5-year follow-up (Diabetes: P = 0.525; Hypertension: P = 0.953; Smoking: P = 0.146). Diabetes (P = 0.454), smoking (P = 0.355), and hypertension (P = 0.727) were not associated with increased odds of major reintervention. Log-rank test similarly showed no differences in reintervention-free survival for major or minor reoperations between those with and without diabetes (P = 0.79), hypertension (P = 0.14), and smoking (P = 0.80). ConclusionsDiabetes, hypertension, and smoking were prevalent among CVI patients, but unlike in PAD patients, they had little to no impact on long-term outcomes or reinterventions after IVS.

Identifying venous clinical severity score thresholds for Clinical-Etiology-Anatomy-Pathophysiology classifications of venous edema and higher.

Venous Clinical Severity Score (VCSS) is a widely used standard for assessing and grading the severity of chronic venous disease (CVD). Prior research highlighted its high validity in detecting and quantifying venous disease. However, there is little, if any, known about the precise thresholds at which VCSS discriminates important stages of deep venous disease. This study sought to elucidate the diagnostic accuracy, thresholds, and correlation at which VCSS detects salient CEAP (Clinical-Etiology-Anatomy-Pathophysiology) classes in deep venous disease progression. A registry of 840 patients who presented with chronic proximal venous outflow obstruction (PVOO) secondary to non-thrombotic iliac vein lesions from August 2011 to June 2021 was retrospectively analyzed. VCSS and CEAP classifications were used to evaluate preoperative symptoms. VCSS was compared to CEAP classes to determine the precise VCSS composite values at which the instrument was able to detect CEAP C3 and higher, C4 and higher, and C5 and higher. Receiver operative characteristic (ROC) curve and area under the curve (AUC) were used to evaluate VCSS for its ability to discriminate disease at these stages of CEAP classification. Spearman's rank coefficient was used to determine the correlation between CEAP VCSS composite as well as individual VCSS components (pain, varicose vein, edema, pigmentation, inflammation, induration, ulcer number, ulcer size, ulcer duration, compression). VCSS composite was able to detect venous edema (C3) and higher at a sensitivity of 68.9% and a specificity of 54.8% at an optimized threshold of 8.5 (AUC = 0.648; 95% C.I. = 0.575-0.721). To detect changes in skin and subcutaneous tissue from CVD (C4) and higher, an optimal threshold of 11.5 was found with a sensitivity of 51.7% and specificity of 76.5% (AUC = 0.694; 95% C.I. = 0.656-0.731). Healed venous ulcer (C4) and higher was detectable at an optimized threshold of 13.5 at a sensitivity of 67.7% and a specificity of 88.9% (AUC = 0.819; 95% C.I. = 0.766-0.873). The correlation between VCSS composites and CEAP was weak (ρ = 0.372; p < .001). Attributes of VCSS that reflect more severe venous disease correlated more closely with CEAP classes, namely pigmentation (ρ = 0.444; p < .001), inflammation (ρ = 0.348; p < .001), induration (ρ = 0.352; p < .001), number of active ulcers (ρ = 0.497; p < .001), active ulcer size (ρ = 0.485; p < .001), and ulcer duration (ρ = 0.497; p < .001). The correlation between CEAP class and the other four components of VCSS were not statistically significant. VCSS composite thresholds of 8.5, 11.5, and 13.5 are threshold values for detecting CEAP classification C3 and higher, C4 and higher, and C5 and higher, respectively. Consistent with prior work, VCSS appears to have a better ability to discriminate CVD at more severe CEAP classifications. In this registry, the correlation between VCSS and CEAP was found to be weak while components of VCSS that suggest more advanced disease exhibited the strongest correlation with CEAP.

Choosing the Right Patient: Understanding the Presenting and Postoperative Complexities of Iliac Vein Stenting in Diabetic Patients With Lower Extremity Ulcers

The incidence of lower extremity ulcers increases with venous disease and is strongly associated with diabetes. However, the effects of treating venous disease on preventing subsequent ulcer formation has not been widely explored. We undertook this study comparing patients with and without diabetes to examine differences in presentation and outcomes of iliac vein stenting (IVS) regarding their lower extremity ulcers. A clinical registry of 877 patients who underwent IVS for chronic proximal venous outflow obstruction (PVOO) from 2011 to 2021 at a single institution was retrospectively analyzed. Patients were stratified into groups based on the presence or absence of diabetes and were followed for an average of 743 days after IVS. Symptoms were quantified using venous clinical severity (VCSS) and Clinical-Etiological-Anatomical-Pathophysiological (CEAP) scores. Postoperative symptom resolution was assessed using Clinical Assessment Score (CAS), which grades symptoms from resolved, significant improvement, mild improvement, no change, or worsened. Major reoperations were defined as interventions requiring a venogram, whereas minor reoperations were defined as endovenous thermal ablation of a superficial vein. Of the 877 patients, 189 (21.5%) had diabetes, whereas 688 (78.5%) did not. Diabetes was associated with a statistically significant greater incidence of hypertension (82.8% vs 42.9%; P < .001), coronary artery disease (27.1% vs 7.4%; P < .001), smoking history (27.6% vs 19.2%; P = .015), and history of malignancy (17.4% vs 9.0%; P = .002). A greater incidence of CEAP 6 at presentation (11.6% vs 6.9%; P = .041) was also seen in the diabetic cohort as were intraoperative findings suggestive of a remote DVT (38.5% vs 23.3%; P < .001). At 1 year postoperatively, diabetic patients reported significantly less “complete resolution” and greater “worsening” symptoms (2.9% vs 12.2% and 3.5% vs 2.3%, respectively; P = .002) than those without diabetes. Diabetic patients with chronic PVOO were more likely to present with cardiovascular comorbidities as well as active ulcers. Intraoperatively, these patients were more likely to have a history of remote DVT. Postoperatively, these patients were less likely to report a resolution of lower extremity symptoms and more likely to experience worsening symptoms. IVS placement for chronic PVOO remains safe and durable and should be considered in patients with or without diabetes including those with active ulcers; however, diabetic patients should be counseled on the worsened prognosis for ulcer resolution.

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

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

Iliac Vein Stenting for Proximal Venous Outflow Obstruction Achieves Near Uniformly Safe Outcomes Across Disparate Age Groups

Iliac Vein Stenting for Proximal Venous Outflow Obstruction Achieves Near Uniformly Safe Outcomes Across Disparate Age Groups

Iliac vein stenting outcomes for patients with superficial venous insufficiency concurrent with deep venous disease

ObjectiveMany patients will present with chronic proximal venous outflow obstruction (PVOO) and superficial venous insufficiency (SVI) at the time of iliac vein stenting. In the present study, we aimed to determine whether differences in outcomes were present for patients receiving an iliac vein stent according to whether concurrent SVI was present. MethodsA registry of 553 patients who had undergone iliac vein stent placement for chronic PVOO from 2011 to 2021 was retrospectively analyzed. Two groups of patients were followed for ≤6 years after initial vein stent placement: group 1 (n = 178; 32.2%) had not had SVI before or after stent placement and group 2 (n = 375; 67.8%) had had SVI at initial iliac vein stent procedure. The patients’ symptoms were evaluated using the venous clinical severity score (VCSS). Postoperative procedures after initial stent placement were recorded. Postoperative procedures included any operation performed after the index iliac vein stent procedure. Endovenous thermal ablation was classified as a minor postoperative procedure, and any intervention with venography was classified as a major postoperative reintervention. Multivariate regression models were used to determine the odds of a major reintervention or minor procedure postoperatively. ResultsAcross the two groups, the mean age (group 1, 65.3 years; group 2, 59.9 years; P < .001), body mass index (27.6 vs 26.1 kg/m2; P = .004), diabetes (32.6% vs 17.6%; P < .001), arterial hypertension (68.5% vs 42.1%; P < .001), and coronary artery disease (16.9% vs 9.6%; P = .048) differed significantly. The time to follow-up was similar between the two groups (P = .915). Longitudinally, both groups had had similar improvements in the composite VCSSs. After multivariable adjustment, group 2 was more likely than group 1 (odds ratio, 5.26; 95% confidence interval, 3.33-8.59; P < .001) to have required a postoperative minor procedure, but not a major reintervention. Group 2 had also averaged a shorter interval from the index procedure to a postoperative procedure than group 1 (525.7 days vs 258.1 days; P < .001). ConclusionsCompared with patients without SVI, those with SVI and chronic PVOO were younger, had had fewer comorbidities, and fared similarly in the change in the composite VCSSs but were more likely to have required a minor procedure and less likely to have required a major reintervention after the index iliac vein stent procedure.

Iliac Vein Stenting Outcomes for Patients with Superficial Venous Insufficiency Concurrent with Deep Venous Disease

Superficial venous insufficiency (SVI) and chronic proximal venous outflow obstruction (PVOO) can occur in the same patient before, during, or after iliac vein stenting, whereas some patients with PVOO never develop SVI. The clinical course of these different patients remains unclear. We undertook this study to determine how SVI would influence the outcomes after vein stenting for chronic PVOO.

Diabetes, Hypertension, and Smoking Do Not Affect Outcomes of Iliofemoral Vein Stenting for Proximal Venous Outflow Obstruction

Diabetes, hypertension, and smoking are well-recognized risk factors for peripheral artery disease, but little is known of their impact on chronic venous insufficiency (CVI). The aim of this study was to evaluate these factors in CVI patients undergoing iliac vein stent placement for chronic iliofemoral venous outflow obstruction. A clinical registry of 708 patients who underwent iliac vein stenting from August 2011 to June 2021 at a single institution was analyzed. Symptoms were quantified using Venous Clinical Severity Score and CEAP class. Both major (any intervention that included venography) and minor (superficial vein ablation) reinterventions after the initial iliac vein stenting were recorded. Univariate differences were analyzed using χ2 or Fisher exact tests for categorical variables and one-way analysis of variance for continuous variables. Logistic regression models were used to determine the unadjusted and adjusted odds ratio (OR) of any minor and major reintervention. A Log-rank test was used to assess differences in reintervention-free survival. Among patients with CVI undergoing vein stent placement, the prevalence of diabetes was 23.0% (n = 163), hypertension was 51.1% (n = 362), and smoking was 22.2% (n = 157). Patients with diabetes (3.6 vs 3.4; P = .062), hypertension (3.6 vs 3.3; P < .001), and smoking (3.7 vs 3.4; P = .003) had higher CEAP scores than those without diabetes, hypertension, and smoking, respectively. Improvement in venous clinical severity score composite scores after vein stenting showed no differences postoperatively (diabetes: P = .513; hypertension: P = .053; smoking: P = .608), at 1-year follow-up (diabetes: P = .666; hypertension: P = .681; smoking: P = .745), or at 5-year follow-up (diabetes: P = .525; hypertension: P = .953; smoking: P = .146) (Table I). Diabetes (OR, 0.80; 95% CI, 0.45-1.43), smoking (OR, 1.34; 95% CI, –0.73 to 2.51), and hypertension (OR, 1.11; 95% CI, 0.63-1.95) were not associated with increased risk of major reintervention after iliac vein stent placement in the multivariate regression models (Table II). Log-rank test similarly showed no differences in reintervention-free survival for major or minor reoperations between those with and without diabetes (P = .79), hypertension (P = .14), and smoking (P = .80). Unlike in peripheral artery disease, diabetes, hypertension, and smoking have little to no impact on long-term outcomes or reinterventions after iliac vein stent placement for CVI.Table IComparison of patients with and without smoking history, diabetes, and hypertension preoperatively and postoperatively.VariablesSmoking historyP valueNo (n = 551)Yes (n = 157)PreoperativeVCSS composite10.5 (4.0)10.5 (4.3).894CEAP class3.4 (1.0)3.7 (1.1).003PostoperativeVCSS composite6.4 (3.6)6.7 (3.7).586Change in VCSS composite postoperative to preoperative3.5 (3.3)3.7 (3.3).608Reintervention1.8 (1.2)2.0 (1.6).091DiabetesP valueNo (n = 545)Yes (n = 163)PreoperativeVCSS composite10.6 (3.9)10.3 (4.5).478CEAP class3.4 (1.0)3.6 (1.2).062PostoperativeVCSS composite6.5 (3.5)6.4 (4.0).827Change in VCSS composite postoperative to preoperative3.6 (3.3)3.4 (3.2).513Reintervention1.8 (1.3)1.9 (1.2).709HypertensionP valueNo (n = 346)Yes (n = 362)PreoperativeVCSS composite10.4 (3.6)10.6 (4.5).594CEAP class3.3 (0.9)3.6 (1.2)<.001PostoperativeVCSS composite6.6 (3.5)6.4 (3.7).727Change in VCSS composite postoperative to preoperative3.9 (5.3)4.6 (5.3).053Reintervention1.8 (1.2)1.9 (1.3).174VCSS, Venous Clinical Severity Score. Open table in a new tab Table IIAdjusted and unadjusted odds of any minor and major reinterventionComparisonModelORP value95% CISmoking historyUnadjusted1.120.595(0.75-1.70)Adjusted1.340.355(0.73-2.51)DiabetesUnadjusted0.640.022(0.43-0.94)Adjusted0.80.454(0.45-1.43)HypertensionUnadjusted0.730.071(0.52-1.03)Adjusted1.110.727(0.63-1.95)CI, Confidence interval; OR, odds ratio. Open table in a new tab

Patients With Post-thrombotic Syndrome Are More Likely to Undergo Venographic Reintervention and Experience Slower Symptom Resolution After Iliac Vein Stenting

Patients undergoing iliac vein stent placement (IVS) for chronic proximal venous outflow obstruction are observed to have two types of stenosis: a more focal stenosis from external compression, also known as nonthrombotic iliac vein lesions (NIVL), or more diffuse stenosis suggestive of post-thrombotic syndrome (PTS) from a remote deep venous thrombosis (DVT). We assessed the influence of PTS on the outcomes of IVS.

Impact of Cancer History on Iliac Vein Stent Placement for Proximal Venous Outflow Obstruction

Cancer has been reported as a significant risk factor for deep vein thrombosis. Little research has been done that directly studies cancer as a risk factor in iliac vein stenting. We undertook the present study comparing patients with cancer to patients without cancer in iliac vein stent placement.

How Does Gender Affect Vein Stent Placement?

Studies have shown significant effects of gender on vascular conditions and outcomes. With vein stent placement emerging as an efficacious and safe treatment of proximal venous outflow obstruction (PVOO) in the iliofemoral veins, it remains unclear how gender might affect the results. We compared the presentation and outcomes after venography, intravascular ultrasound, and vein stent placement in male and female patients with chronic PVOO.

Improvement in Thoracic Outlet Syndrome Symptoms After Iliac Vein Stenting for Iliac Vein Proximal Venous Outflow Obstruction

An association between chronic proximal venous outflow obstruction (PVOO) in iliac veins and thoracic outlet syndrome (TOS) has not been previously reported. We observed some patients with iliac vein PVOO to have concurrent TOS symptoms. After iliac vein stenting, we witnessed not only the expected improvement in lower extremity venous symptoms but also significant improvement in TOS symptoms. This study states our findings and investigates this phenomenon.

Gender Differences in Vein Stenting

Studies show significant impact of gender on vascular conditions and outcomes. With vein stent placement emerging as an efficacious and safe treatment for proximal venous outflow obstruction (PVOO) in iliofemoral veins, it remains unclear how gender might impact results. This study compares male and female cohorts that underwent venogram, intravascular ultrasound, and vein stent placement for chronic PVOO.

Comparison of Iliofemoral Vein Stenting in Octogenarians and Older to the Younger Population

Octogenarians and nonagenarians represent a significant proportion of patients undergoing vein stenting for chronic proximal venous outflow obstruction (PVOO). This study compares symptomatic improvement after iliac vein stenting in this patient cohort with younger patients undergoing intervention.

Trends in Pharmacologic Management After Iliac Venous Stent Placement

The optimal pharmacologic regimen after vein stent placement for chronic proximal venous outflow obstruction (PVOO) varies significantly amongst vascular surgeons. This study was conducted to highlight this concern, and support the need for a uniform treatment algorithm for pharmacological management following venous stent placement.

Iliac Vein Stenting for Chronic Proximal Venous Outflow Obstruction in a Predominantly Asian-American Cohort

Chronic proximal venous outflow obstruction (PVOO) presentation, treatment needs, and outcomes differ in Asian Americans compared with non-Asian patients. Study Summary: This was a large (N = 462) study of consecutive patients with PVOO that included 336 (73%) Asian Americans treated in a 3-year time span with a 90% follow-up during 695 days. Asian Americans were more likely to present with varicose veins rather than with ulceration and to have bilateral iliac venous stent placement and less likely to have had a deep venous thrombosis and any reinterventions. Follow-up outcome scores were worse at 30-days but improved at 1 year compared with non-Asians. This observational study of Asian Americans' presentation and response to treatment for PVOO is important, showing the effects of chronic venous insufficiency in a population. The literature has shown ethnic differences in the incidence and prevalence of venous thromboembolism in Asians, but this is the first study of which I am aware looking at iliac venous disease and interventions. More epidemiologic data are needed to understand interethnic disparities and possibly the relative roles of genetic and environmental factors.

A Potential Utility of Pulsed-Wave Doppler in Iliocaval Outflow Obstruction

Proximal venous outflow obstruction (PVOO) in the iliocaval veins is frequently suspected after history and physical examination. A simple, noninvasive test that can indicate if PVOO is present, prior to more invasive imaging, would be very helpful but is currently unavailable. We undertook this study to determine if pulsed-wave Doppler (PW) can signify PVOO. PW is known to indicate proximal occlusion when it does not exhibit any respiratory variations. Does PW exhibit any clues when the proximal vein is stenotic but not occluded?

Iliac Vein Stenting for Chronic Proximal Venous Outflow Obstruction in a Predominantly Asian-American Cohort

We investigated the outcome of vein stenting placement for chronic proximal venous outflow obstruction (PVOO) in a predominantly Asian-American cohort to improve patient selection, enhance technical approach, and better define quality measurements of this emerging vascular intervention. A total of 462 consecutive patients, 73% Asian American (n=336), who underwent iliac vein stenting for chronic PVOO from October 2013 to July 2016 were reviewed. Postoperative outcomes at five follow-up visits were assessed. Wilcoxon-Mann-Whitney and Kruskal-Wallis tests were run for demographic and operative variables. Ordered logistic regressions were run for the outcome at each time point, and Chi-squared tests as well as Fisher's exact tests were used for categorical variables. Follow-up was maintained in 90% of patients, with a mean follow-up time of 695days. Asian-American patients were more likely to present with varicose veins (77.4% vs. 54.8%, P<0.001), and non-Asian patients were more likely to present with active ulceration (26.2% vs. 5.1%, P<0.001). Asian-American patients were more likely to have bilateral stents placed (61.6% vs. 50%, P=0.026) and were less likely to have reinterventions (11.3% vs. 27.8%, P<0.001), a history of deep vein thrombosis (8.3% vs. 29.4%, P<0.001), or intraoperative findings of chronic postphlebitic changes (17.6% vs. 33.3%, P<0.001). Kruskal-Wallis tests were significant for improvement in patients of all the Clinical, Etiology, Anatomy, Pathophysiology classes at 30days (P=0.041), 90days (P=0.045), 6months (P=0.041), and 1year (P<0.01). The Asian-American population had improved but comparatively lower follow-up scores at the 30-day mark (48% significantly improved or better vs. 63%, P=0.008) but higher follow-up scores at the >1year mark (80% significantly improved or better vs. 59%, P<0.001). Asian-American patients undergoing vein stent placement for chronic PVOO had comparatively worse outcomes than non-Asian patients at 30 days and better outcomes after one year. These patient groups had different outcomes postoperatively and outcomes which evolve differently over time.

Venous Stenting in Proximal Venous Outflow Obstruction – Lessons Learned from 500 Cases

Introduction - Venous stenting is emerging as an important treatment strategy in venous disease. What is the real world experience with this procedure? This study reviews our experience with venous stenting in chronic venous insufficiency, highlighting patient selection, procedural considerations, outcomes, and re-interventions. Methods - This is a retrospective study of 500 patients who underwent venous stenting for chronic proximal venous outflow obstruction (PVOO) in the iliac veins from October 2013 to August 2016 at one centre. Preoperatively, we utilized venous duplex scan and magnetic resonance venogram to assist in patient selection. Intraoperative evaluation comprised of bilateral venogram and intravascular ultrasound. Wallstents were used in all cases (Boston Scientific, MA). Patients were discharged on day of procedure with rivaroxaban 10 mg initially followed by long-term Aspirin 81 mg. Wilcoxon-Mann-Whitney, Kruskal-Wallis, and logistic regressions were used in statistical analysis of variables and outcomes. Results - Of these 500 patients, follow-up was maintained in 90% of patients with a mean follow-up 320 days. Mean age of patients was 60 years old (SD 13.4 years) and 57% were female. Preoperatively, edema was present in 90.5%, and active ulceration 10.7%. 85 patients (17%) presented with persistent symptoms after a prior endovenous thermal ablation or surgery for superficial venous disease, and 69 patients (13.8) presenting with post-thrombotic syndrome. Among patients without any known DVT history, 21.5% had findings of chronic phlebitic changes (long segment diffuse disease, occlusion of vessel, intraluminal filling defects) on venogram or IVUS. Bilateral vein stents were performed in 59%. Kruskal-Wallis tests were significant for improvement (symptoms, CEAP class, and physical exam) in patients at thirty days (p=0.027), ninety days (p=0.045), six months (p=0.037), and one year (p=0.012). Ordered logistic regressions found the presence of edema (coefficient 1.59, 95% CI [0.52, 2.65], p=0.004), active ulceration (95% CI [0.022, 3.40], p=0.047), and decreased number of stents placed (coefficient -0.56, 95% CI [-1.08, -0.036], p=0.036) to predict increased improvement at thirty days, and a history of DVT (coefficient: -0.94, 95% CI [-1.79, -0.096], p=0. 029) to predict decreased improvement at one year post-operatively. Wilcoxon-Mann-Whitney tests were significant for more improvement in patients who had unilateral versus bilateral stents placed at thirty days (p=0.013) and six months (p=0.039). Major re-interventions (61.7% for recurrent symptoms, 17.6% for persistent symptoms, 6% for DVT) were performed in 7.6% of patients. Mean time to re-intervention was 191 days, and re-interventions were more prevalent (29. 4%) among patients with a known history of DVT. Conclusion - Our experience with venous stenting in chronic PVOO on an expanded scale suggested a satisfactory outcome at one year. Those patients with a prior history of DVT have poorer outcomes after venous stenting. Unilateral stents have better outcomes than bilateral stents, but the difference may reflect complexity of disease. Approximately 8% of patients will require a secondary re-intervention. Patient selection, procedural indications, and optimal pharmacologic therapy after venous stenting need further studies and clarification.

FJVIS 16. Chronic Low Back Pain Associated With Proximal Venous Outflow Obstruction

FJVIS 16. Chronic Low Back Pain Associated With Proximal Venous Outflow Obstruction