Outcomes of endovascular reconstruction of the inferior vena cava with self-expanding nitinol stents

Double-barrel iliocaval reconstruction using closed-cell dedicated venous stents

OBJECTIVE

Double-barrel iliocaval reconstruction is performed by deploying two stents simultaneously in a side-by-side, or "double-barrel," configuration in the inferior vena cava (IVC) with extension into the bilateral common iliac veins. The aim of this study was to examine the outcomes of double-barrel reconstruction using closed-cell dedicated venous stents for the treatment of iliocaval deep venous thrombosis and iliac vein compression syndrome.

METHODS

All endovascular procedural reports comprising vascular surgery and interventional radiology operators from a single urban academic hospital between May 1, 2019, and April 30, 2021, were retrospectively searched. A cohort of 22 consecutive patients who underwent double-barrel iliocaval stenting with closed-cell dedicated venous stents for chronic or acute-on-chronic iliocaval venous disease without prior endovascular iliocaval repair was identified. Baseline characteristics, procedural data, and patient outcomes were determined via a manual review of preprocedure clinical notes, diagnostic imaging studies, procedure notes and images, and follow-up clinical notes.

RESULTS

The median (range) age was 59 (27-81) years, and the cohort consisted of 59.1% female. The most common presenting symptoms of venous disease were lower extremity swelling (90.9%) and pain (50.0%). CEAP clinical classification was C3 in 86.4% of patients, whereas the remainder had C4 disease. Most patients (72.7%) had post-thrombotic syndrome, 22.7% had a nonthrombotic iliac vein lesion, and one patient (4.5%) had the congenital absence of the infrarenal IVC. A total of 40.9% of patients had a pre-existing IVC filter at the time of treatment. Six of the 22 patients underwent concurrent pharmacomechanical thrombectomy during the index iliocaval reconstruction and stenting procedure. The number of stents placed ranged from 2 to 5. With a mean follow-up period of 7.1 months, ranging from 12 days to 16.7 months, the freedom from reintervention rate was 90.9%. Twenty of 22 patients achieved subjective improvement or resolution of symptoms. The major adverse event rate was 9.1%, as two patients had access site complications requiring intervention.

CONCLUSIONS

Double-barrel iliocaval reconstruction with closed-cell dedicated venous stents for the treatment of post-thrombotic syndrome or iliac vein compression syndrome is technically feasible and clinically effective with a low reintervention rate.

A Systematic Review of the Safety and Efficacy of Inferior Vena Cava Stenting

OBJECTIVE

Inferior vena cava (IVC) stenting may provide benefit to patients with symptomatic obstruction; however, there are no devices currently licensed for use in the IVC and systematic reviews on the topic are lacking. The aim of this study was to carry out a systematic review of the literature and meta-analysis to investigate the safety and efficacy of IVC stenting in all adult patient groups.

DATA SOURCES

The Medline and Embase databases were searched for studies reporting outcomes for safety and effectiveness of IVC stenting for any indication in series of 10 or more patients.

REVIEW METHODS

A systematic review of the literature was carried out according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Thirty-three studies were included describing 1 575 patients. Indications for stenting were malignant IVC syndrome (229 patients), thrombotic disease (807 patients), Budd-Chiari syndrome (501 patients), and IVC stenosis post liver transplantation (47 patients). The male:female ratio was 2:1 and the median age ranged from 30 to 61 years. The studies included were not suitable for formal meta-analysis as 30/33 were single centre retrospective studies with no control groups and there was considerable inconsistency in outcome reporting. There was significant risk of bias in 94% of studies. Median reported technical success was 100% (range 78 - 100%), primary patency was 75% (38 - 98%), and secondary patency was 91.5% (77 - 100%). Major complications were pulmonary embolism (three cases), stent migration (12 cases), and major bleeding (15 cases), and there were three deaths in the immediate post-operative period. Most studies reported improvement in clinical symptoms but formal reporting tools were not used consistently.

CONCLUSION

The evidence base for IVC stenting consists of predominantly single centre, retrospective, observational studies that have a high risk of bias. Nonetheless the procedure appears safe with few major adverse events, and studies that reported clinical outcomes demonstrate improvement in symptoms and quality of life. Randomised controlled trials and prospective registry based studies with larger patient numbers and standardised outcome are required to improve the evidence base for this procedure.

Performance of Open and Closed Cell Laser Cut Nitinol Stents for the Treatment of Chronic Iliofemoral Venous Outflow Obstruction in Patients Treated at a Single Centre

OBJECTIVE

A number of dedicated self expanding nitinol stents have been developed for use in the venous system, with both open cell (OC) and closed cell (CC) designs available. Data comparing these different designs are lacking. The objective of this study was to evaluate outcomes in patients treated with open and closed cells for unilateral chronic iliac vein obstruction.

METHODS

A single centre retrospective cohort study was conducted, including all patients treated with a dedicated nitinol venous stent between 2014 and 2019. Stent patency and details of re-interventions (including lysis, venoplasty, reinforcement, extension, arteriovenous fistula formation) were examined in the first post-operative year. Subgroup analysis described outcomes for patients treated with OC and CC stents ending above the inguinal ligament and those who required extension into the common femoral vein. Cox regression analysis was used to identify factors associated with loss of primary patency.

RESULTS

A total of 207 patients were included (OC 100 patients, CC 107 patients). There was no significant difference between the groups for age (OC 42 years, CC 44 years); gender (OC and CC 67% female); presence of post-thrombotic lesions (OC 71%, CC 73%); stenting across the inguinal ligament (OC 58%, CC 56%), or presence of inflow disease (OC 49%, CC 47%). Primary and cumulative patency at 12 months were similar between groups (primary: OC 63%, CC 65%; cumulative: OC 93%, CC 90%). Patients with a CC stent across the inguinal ligament had a greater risk of needing multiple re-interventions at one year compared with those with an OC stent (odds ratio 2.84, 95% confidence interval [CI] 1.16 - 6.9) but overall, the only factor significantly associated with loss of primary patency was inflow vessel disease (hazard ratio 3.39, 95% CI 1.73 - 6.62, p < .001).

CONCLUSION

OC and CC dedicated nitinol venous stents were observed to perform similarly in terms of patency and symptom improvement at one year. Disease of the inflow vessels was the most important factor associated with a loss of stent patency irrespective of stent design.

Medium-term outcomes after inferior vena cava reconstruction for acute and chronic deep vein thrombosis and retroperitoneal fibrosis

OBJECTIVE

In the present study, we evaluated the technical and clinical outcomes after endovascular inferior vena cava (IVC) reconstruction in patients with nonmalignant obstruction.

METHODS

The preoperative, procedural, and follow-up medical records and imaging studies were retrospectively reviewed for 59 consecutive patients who had undergone endovascular IVC reconstruction for nonmalignant obstruction from February 2014 to January 2019. The patients were classified into three groups according to the quality of their infrainguinal inflow vessels. The outcomes measured were the primary, primary-assisted, and secondary patency rates, reintervention rates, and symptomatic resolution.

RESULTS

The indications for treatment were post-thrombotic syndrome (n = 41), acute deep vein thrombosis (n = 12), and retroperitoneal fibrosis (n = 6). The median patient age was 37 years, 11 months, 71.2% were men, and 32.2% had a diagnosis of thrombophilia, with no significant difference in these demographics between the three inflow groups. The median follow-up duration was 2 years, 3 months (range, 6 months to 6 years, 5 months). The whole-cohort primary patency was 91.2%, 71.0%, and 24.1% at 1, 3, and 5 years, respectively. Secondary patency was 76.7% at 1 year and 66.4% at both 3 and 5 years. Inflow group A (no post-thrombotic disease in the femoral or deep femoral veins) demonstrated significantly higher primary patency compared with group B (stenotic disease in one or two infrainguinal inflow veins; P = .009) and significantly higher secondary patency than for both groups B (P = .008) and C (all three infrainguinal inflow veins had stenosed or femoral and/or deep femoral vein occlusion was present; P = .04). In post-thrombotic syndrome patients, the Villalta scores had decreased from a mean of 14.2 to 8.1 at 1 year and 6.8 at 2 years, and the Venous Insufficiency Epidemiological and Economic Study Quality of Life score had improved from a mean of 19.8 to 54.1 and 57.3 at 1 and 2 years, respectively. In the patients with acute deep vein thrombosis, the Villalta score was 2.8 at 1 year and 0 at 2 years. In the patients with retroperitoneal fibrosis, the Venous Insufficiency Epidemiological and Economic Study Quality of Life score had improved from a mean of 25.3 at baseline to 44 at 6 months.

CONCLUSIONS

Endovascular IVC reconstruction for nonmalignant obstruction can achieve good patency and clinical improvement, although the outcomes were poorer for patients with post-thrombotic disease of the femoral and deep femoral veins.

A systematic review and meta-analysis of the treatment of obstructive chronic deep venous disease using dedicated venous stents

OBJECTIVES

This review aims to summarise the efficacy and safety of dedicated venous stenting for the treatment of obstructive chronic deep venous disease. The approaches to stenting and post-procedural management of different vascular units are also highlighted.

METHODS

MEDLINE and Embase were searched to identify relevant literature on dedicated venous stents published from January, 2010 to May, 2020. The patient population and study characteristics; procedural characteristics; and outcomes related to post-stenting symptoms, health-related quality of life, patency and complications were analysed.

RESULTS

Sixteen single-arm observational studies were included from 2,366 studies identified from key-word searches. In total, 1,688 patients were included, of which 70.5% had post-thrombotic syndrome and the remainder had non-thrombotic iliac vein lesions. Nine studies (n = 848), stated whether lesions were stenotic (36.6%) or occlusive (63.4%). Seven studies did not report the lesion characteristics (n = 840). Eight different dedicated venous stent brands were employed. 73.4% of ulcers healed at last follow-up. The remaining symptomatic changes were described narratively; sustained improvements in pain, venous claudication and oedema following stenting were observed. Significant post-stenting improvements in health-related quality of life were noted, as measured by the Chronic Venous Insufficiency Questionnaire-20 instrument. Overall, the most frequently reported complications were in-stent occlusion (n = 204), in-stent stenosis (n = 149) and minor bleeding (n = 77). At 12 months, the primary patency ranged from 59% to 94%, whilst the secondary patency ranged 87% to 100%. The pooled-primary and secondary stent patency rates at 12 months were 74.0% and 90.4%, respectively. The incidence of major and minor bleeding was 1.9% and 4.7%, respectively; bleeding complications were more common in patients undergoing hybrid intervention.

CONCLUSION

Deep venous stenting using dedicated venous stents is a safe technique to treat obstructive chronic deep venous disease and within the limitations of this study, is associated with good patency outcomes and symptomatic improvement.

Reversal of cardiopulmonary exercise intolerance in patients with post-thrombotic obstruction of the inferior vena cava

BACKGROUND

It is unclear whether cardiopulmonary exercise intolerance in patients with chronic obstruction of the inferior vena cava (IVC) is reversible following endovascular IVC reconstruction.

METHODS

In 17 patients (mean age 45 ± 15 years, 71% men) with post-thrombotic syndrome due to IVC obstruction and preserved left ventricular ejection fraction (mean 58 ± 3%), we performed cardiopulmonary exercise testing before and 3 months after IVC reconstruction (mean 4.1 ± 1.5 implanted stents). The median time from latest episode of deep vein thrombosis to intervention was 150 (interquartile range 102-820) days.

RESULTS

At baseline, 12 (71%) patients reported New York Heart Association (NYHA) class II or III symptoms, 76% did not achieve >85% of predicted oxygen uptake at peak exercise (mean 61.8 ± 13.7%). After IVC reconstruction, the following changes were observed at anaerobic threshold: work rate increased by 14.6 W, 95%CI (-0.7; 30.0), oxygen uptake increased by 1.8 ml/kg, 95%CI (0.3; 3.3). Oxygen pulse increased by 1.95 ml per beat, 95%CI (1.12; 2.78), corresponding to a mean relative increase of 22.5%, 95%CI (12.4; 32.7) (p < 0.001). The following changes were observed at peak exercise: work rate increased by 48.1 W, 95%CI (27.8; 68.4), oxygen uptake increased by 6.4 ml/kg, 95%CI (3.8; 9.1). Oxygen pulse increased by 2.68 ml per beat, 95%CI (1.60; 3.76), corresponding to a mean relative increase of 29.4%, 95%CI (17.7; 41.2) (p < 0.001). At follow-up, 5 (29%) patients remained in NYHA class II.

CONCLUSIONS

In patients with chronic IVC obstruction, cardiopulmonary exercise intolerance as a result of impaired cardiac filling is at least partially reversible following endovascular IVC reconstruction.

STUDY REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT02433054.

Inferior vena cava-syndrome

Inferior vena cava syndrome (IVCS) is caused by agenesis, compression, invasion, or thrombosis of the IVC, or may be associated with Budd-Chiari syndrome. Its incidence and prevalence are unknown. Benign IVCS is separated from malignant IVCS. Both cover a wide clinical spectrum reaching from asymptomatic to highly symptomatic cases correlated to the underlying cause, the acuity, the extent of the venous obstruction, and the recruitment and development of venous collateral circuits. Imaging is necessary to determine the underlying cause of IVCS and to guide clinical decisions. Interventional therapy has changed the therapeutic approach in symptomatic patients. This article provides an overview over IVCS and focuses on interventional therapeutic methods and results.

Self-Expandable Nitinol Stents for the Treatment of Nonmalignant Deep Venous Obstruction

BACKGROUND

Angioplasty with stent placement is a therapeutic option for patients with acute thrombotic, postthrombotic, and nonthrombotic obstruction of the iliofemoral veins or inferior vena cava. Previous studies of steel-alloy stents described variable patency rate across indications.

METHODS

The prospective Swiss Venous Stent Registry includes patients treated with self-expandable nitinol stents for deep venous obstruction. Routine follow-up visits include serial duplex ultrasound for stent patency assessment. The primary outcome was primary stent patency. The secondary outcome was venous thromboembolisms. We studied the rate of stent occlusion and potentially contributing factors.

RESULTS

We included 379 patients: 160 with acute thrombotic, 193 with postthrombotic, and 26 with nonthrombotic deep vein obstruction. The mean age was 46±18 years; 55% were women. The cumulative 3-year primary patency rate was 80.5% (95% CI, 73.0%-88.0%) for acute thrombotic, 59.2% (95% CI, 50.4%-68.0%) for postthrombotic, and 100% for nonthrombotic obstruction (log-rank, P<0.0001). Annualized rates of stent occlusion or venous thromboembolism were 7.8 (acute thrombotic), 15.0 (postthrombotic), and 0 (nonthrombotic) events/100 patient-years. In a multivariable Cox regression model, postthrombotic femoral veins at baseline (hazard ratio, 2.64 [95% CI, 1.53-4.56]) and the number of stents (hazard ratio, 1.22 [95% CI, 1.06-1.40]) were associated with stent occlusion after conditioning for age, sex, and clinically relevant factors.

CONCLUSIONS

The rate of stent occlusion (patency loss) and venous thromboembolism varies substantially across indications, also with dedicated venous nitinol stents. Patients with postthrombotic femoral veins and those who received multiple stents were characterized by the highest risk. Registration: URL: https://clinicaltrials.gov. Unique identifier: NCT02433054.

Stent Placement for Malignant Inferior Vena Cava Syndrome in a Patient with Recurrent Colon Cancer

A 70-year-old man was admitted to our hospital with gait disturbance due to marked edema of the lower limbs for more than 6 months. He had been receiving systemic chemotherapy over two years for multiple recurrence after sigmoid colon cancer resection. Contrast-enhanced computed tomography demonstrated severe inferior vena cava (IVC) stenosis due to compression by lymph node metastases, i.e. IVC syndrome. As increased doses of diuretic agents failed to improve the edema, IVC stent placement was performed. This led to significant improvement of the edema and complete gait normalization. This case demonstrates the efficacy of IVC stent placement for IVC syndrome.

Extravascular reconstruction of a congenitally absent inferior vena cava

Congenital absence of the inferior vena cava is an uncommon venous anomaly with treatment algorithms consisting of predominately medical management. We present a case of a 36-year-old man with venous ulcers who had failed conservative treatment for recurrent venous ulcers. From a catheter directed approach, we were able to develop an extravascular retroperitoneal space and perform an iliocaval reconstruction with Wallstents. At 1-year postoperatively, his leg pain and edema had resolved, and had achieved resolution of his venous ulceration.

Braided or laser-cut self-expanding nitinol stents for the common femoral vein in patients with post-thrombotic syndrome

BACKGROUND

Chronic obstruction of the common femoral vein in patients with post-thrombotic syndrome after iliofemoral or iliocaval deep vein thrombosis has remained a challenge for endovascular treatment. The patency rates and clinical outcomes of laser-cut and braided nitinol stents extending to the common femoral vein have not yet been studied.

METHODS

From the Swiss and Arnsberg Venous Stent Registries, we included 150 patients with post-thrombotic syndrome (mean age, 44 ± 16 years; 48% women) with laser-cut (n = 101) or braided nitinol (n = 49) stents placed into the common femoral vein across the inguinal ligament. Routine follow-up included duplex ultrasound examinations and assessment of clinical scores. The primary study outcomes were the primary and secondary patency rates at 12 months.

RESULTS

Overall, the mean number of implanted stents was 2.6 ± 1.7. The proximal stent landing zone was the inferior vena cava in 32 patients (21%), the iliac vein in 106 patients (76%), and the common femoral vein in 5 patients (3%). The primary patency rate was 67.3% (95% confidence interval [CI], 58.0%-76.6%) in the laser-cut group and 86.7% (95% CI, 75.3%-98.1%) in the braided stent group (log-rank, P = .016). The corresponding secondary patency rates were 93.9% (95% CI, 89.2%-98.6%) and 100% (log-rank, P = .10). The median improvement in the Villalta score from baseline to the latest follow-up was 4 points (interquartile range, 2-6 points), without significant differences between the two groups. Symptomatic common femoral vein stent fractures were observed in four patients (4%) with laser-cut stents but in no patient with braided stents.

CONCLUSIONS

The use of braided nitinol stents for common femoral vein obstruction appeared to be associated with favorable primary patency rates at 12 months compared with laser-cut nitinol stents. Further studies are needed to confirm that braided nitinol stents remain patent and might be less prone to fractures in the long term.

Duplex Ultrasound Investigation for the Detection of Obstructed Iliocaval Venous Stents

OBJECTIVE

Duplex ultrasound (DUS) is used for routine surveillance of stents in iliocaval veins, but direct visualisation is often challenging. Duplex ultrasound criteria for detecting venous stent obstruction (VSO) have not been defined to date.

METHODS

A nested case control study of 120 patients (42 ± 17 years, 53% women, mean 2.7 ± 1.8 stents) was performed, and the performance of various duplex parameters for detecting VSO (defined as > 50% lumen diameter reduction or occlusion) was tested, confirmed by biplane venography or intravascular ultrasound (IVUS). Forty patients with VSO (25 with stent occlusion, 15 with >50% in stent stenosis) were matched to 80 control patients by age, gender and index diagnosis who fulfilled the following criteria: (1) ongoing symptom control (Villalta score < 5), (2) good image quality of entire stent segment, (3) spontaneous colour Doppler signal > 50% of lumen in entire stent segment, (4) at least two DUS where the baseline DUS was obtained within 24 h after successful venous intervention.

RESULTS

The best test was the combination of peak flow velocity and flow pattern analysis at the stent inlet. A peak flow velocity >10 cm/s and a flow pattern spontaneously modulated by respiration ruled out VSO with a specificity of 93.7% (95% CI 86.0%-97.3%). A peak flow velocity ≤10 cm/s or any Doppler flow pattern other than spontaneously modulated by respiration was 92.1% (95% CI 79.2%-97.3%) sensitive to detect VSO.

CONCLUSION

The combination of peak flow velocity and analysis of Doppler flow pattern at the stent inlet is accurate to diagnose or rule out stent occlusion. Indirect criteria should always be combined with direct visualisation of iliocaval stents since those may be less sensitive for detecting stent stenosis.

Total endovenous recanalization and stent reconstruction for naïve non-inferior vena cava filter-associated chronic iliocaval occlusive disease: Placement of 352 venous stents in 69 debilitated patients

The aim of this study was to report the technical success, adverse events, clinical outcomes, and long-term stent patency of iliocaval stent reconstruction for naïve, non-inferior vena cava (IVC) filter-related, chronic iliocaval thrombosis. A total of 69 patients, including 47 (68%) men, with a mean age of 36 years (range: 8-71 years), underwent first-time iliocaval stent reconstruction for non-IVC filter-associated iliocaval thrombosis. The mean number of prothrombotic risk factors was 2.2 (range: 0-5), including 30 (43%) patients with IVC atresia. Upon initial presentation, the Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) classification was C3 in 55 (80%) patients, C4 in four (5.8%) patients, C5 in one (1.4%) patient, and C6 in seven (10%) patients. Technical aspects of stent reconstruction, technical success, adverse events, 2-week and 6, 12, and 24-month clinical response, and 6, 12, and 24-month primary, primary-assisted, and secondary stent patency rates were recorded. Technical success was defined as recanalization and stent deployment. Adverse events were reported according to the Society of Interventional Radiology classification system. Clinical success was defined as a 1-point decrease in CEAP classification and stent patency was defined by the Cardiovascular and Interventional Radiological Society guidelines. The technical success rate was 100%. There were 352 venous stents deployed during stent reconstructions. One (1.4%) severe, four (5.8%) moderate, and four (5.8%) minor adverse events occurred and median post-procedure hospitalization was 1 day (range: 1-45 days). Clinical success at 2 weeks and 6, 12, and 24 months was 76%, 85%, 87%, and 100%, respectively. The estimated 6, 12, and 24-month primary patency rates were 91%, 88%, and 62%, respectively. The estimated 6, 12, and 24-month primary-assisted patency rates were 98%, 95%, and 81%, respectively. The estimated 6, 12, and 24-month secondary-assisted patency rates were all 100%. In conclusion, iliocaval stent reconstruction is an effective treatment for non-IVC filter-associated chronic iliocaval thrombosis with high rates of technical success, clinical responses, and stent patency.