Use of Computed Tomography and Magnetic Resonance Imaging in Central Venous Disease

A meta-analysis of the medium- to long-term outcomes in patients with chronic deep venous disease treated with dedicated venous stents

OBJECTIVE

This review summarizes the safety profile, stent patency, and clinical effectiveness of dedicated venous stents for the treatment of chronic deep venous disease. The approaches to stenting and post-procedural management of different vascular units are also explored.

METHODS

The MEDLINE and Embase databases were searched for pertinent literature published from January 2010 to January 2023. Outcomes related to post-stenting symptoms and health-related quality of life were described narratively. A meta analysis was conducted to evaluate stent patency, ulcer healing, bleeding, and 30-day stent thrombosis, and these outcomes were presented as proportion event rates.

RESULTS

Seventeen studies were identified comprising of 2218 patients. 62.7% of individuals had post-thrombotic stenosis or occlusion. The majority of patients (78.6%) were noted to have complete occlusions of their deep veins before stenting. Eleven different dedicated venous stents were deployed. At 12 months, the primary patency rate was 83% (95% confidence interval [CI]: 76%-90%), the primary-assisted patency rate was 90% (95% CI: 85%-96%), and the secondary patency rate was 95% (95% CI: 92%-98%). A significant improvement in health-related quality of life was demonstrated after intervention. In total, 68.8% (95% CI: 52.0%-83.7%) of ulcers healed at the last follow-up. The remaining symptomatic changes were described narratively; improvements in pain, venous claudication, and edema after stenting were observed. Seventeen deaths occurred, but none were linked to the stenting procedures. A total of 159 cases (7.2% of patients) of in-stent stenosis were observed, whereas 110 stents (5.0% of patients) were occluded. The incidence of major and minor bleeding was 1.7% (95% CI: 1.0%-2.5%) and 3.2% (95% CI: 1.3%-5.6%), respectively, more commonly seen in patients undergoing hybrid intervention.

CONCLUSIONS

Deep venous stenting using dedicated venous stents is a safe technique to treat chronic deep venous stenosis and/or occlusion. Within the limitations of this study, deep venous stenting is associated with good patency rates and symptomatic improvement.

The background and role of catheter-directed thrombolysis evolving procedures for acute iliofemoral deep venous thrombosis

Minimal invasive treatment such as early endovenous thrombus removal for iliofemoral deep venous thrombosis (DVT) emerged in the end of last century. The principle is catheter-directed thrombolysis (CDT) using either plasminogen activating agents alone, as ultrasound-assisted CDT, or in combination with mechanical devices as pharmaco-mechanical CDT. The interest for this treatment modality is the high rate of post-thrombotic syndrome (PTS) with anticoagulation (AC) alone, especially after iliofemoral DVT. Recently published randomized controlled trials (RCTs) comparing early thrombus removal with AC alone, as well as non-randomized studies, have demonstrated favorable rates, or at least a decrease of moderate and severe PTS, in favor of these procedures. This article will summarize the background and evolution of the procedures in the last three decades and discuss fundamental criteria for inclusion and exclusion, focusing on the procedures regarding thrombus age and location, technical issues, complications and results including different outcome measures for PTS, for which iliac DVT involvement is a massive risk factor to be prevented.

A Spiky Silver-Iron Oxide Nanoparticle for Highly Efficient Targeted Photothermal Therapy and Multimodal Imaging of Thrombosis

Thrombosis and its complications are responsible for 30% of annual deaths. Limitations of methods for diagnosing and treating thrombosis highlight the need for improvements. Agents that provide simultaneous diagnostic and therapeutic activities (theranostics) are paramount for an accurate diagnosis and rapid treatment. In this study, silver-iron oxide nanoparticles (AgIONPs) are developed for highly efficient targeted photothermal therapy and imaging of thrombosis. Small iron oxide nanoparticles are employed as seeding agents for the generation of a new class of spiky silver nanoparticles with strong absorbance in the near-infrared range. The AgIONPs are biofunctionalized with binding ligands for targeting thrombi. Photoacoustic and fluorescence imaging demonstrate the highly specific binding of AgIONPs to the thrombus when functionalized with a single chain antibody targeting activated platelets. Photothermal thrombolysis in vivo shows an increase in the temperature of thrombi and a full restoration of blood flow for targeted group but not in the non-targeted group. Thrombolysis from targeted groups is significantly improved (p < 0.0001) in comparison to the standard thrombolytic used in the clinic. Assays show no apparent side effects of AgIONPs. Altogether, this work suggests that AgIONPs are potential theranostic agents for thrombosis.

Long-term integrity of 53 iliac vein stents after catheter-directed thrombolysis

BACKGROUND

Long-term surveillance data on venous stent integrity is sparse. There is limited knowledge on whether duplex ultrasound (DUS) can detect potential stent deformities such as kinking, straightening, and fracture, which may impact long-term patency of the stented veins.

PURPOSE

To assess venous stent integrity after at least five years of follow-up and to establish the efficacy of DUS as surveillance in patients with venous stent.

MATERIAL AND METHODS

A total of 45 patients with acute iliac-femoral deep vein thrombosis (DVT) treated with catheter directed thrombolysis (CDT) and stenting >5 years before follow-up. Stents were evaluated with 3D volume low dose non-contrast computed tomography (CT) and DUS for kinking, straightening, stent fracture, and patency. Results from CT scans and DUS were compared to assess the overall agreement between the methods.

RESULTS

Median follow-up was 13.2 years (mean = 11.2 years; range = 5.2-15.8 years). 3D CT reconstructions showed normal stent configuration in 47 stents (89%). All intact stents were identified by DUS. In the remaining six stents, 3D CT reconstructions showed compression, tapering, kinking, and minor fracture. DUS recognized all stent complications except the minor fracture. Overall agreement between CT and DUS was 98% (kappa = 0.90). Two cases of stent occlusion were found.

CONCLUSION

The long-term physical resilience of iliac vein stents evaluated with 3D CT in patients treated with CDT for iliofemoral DVT was high. Stent deformities were mostly compression, whereas fracture was rarely seen. DUS seems to be sufficient to evaluate venous stent integrity.

Comparison of intravascular ultrasound and magnetic resonance venography in the diagnosis of chronic iliac venous disease

BACKGROUND

The diagnosis of chronic iliofemoral venous obstruction (CIVO) can be made with several different modalities. Intravascular ultrasound (IVUS) 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) to IVUS in the diagnosis of CIVO.

METHODS

From January, 2016 to December, 2020, records of all patients who underwent pre-operative MRV and then IVUS in the evaluation of CIVO were retrospectively analyzed.

RESULTS

505 patients were evaluated by any modality for CIVO. 15% (78) of these patients were evaluated by MRV. Patients who had failed a trial of conservative therapy for at least 3 - 6 months and who had disabling and life-style 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 and MRV data was 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. 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 mean difference in area between IVUS and MRI were 74.1% for CIV and 56.9% for EIV. The sensitivity of MRV was 93% and 100% while the specificity was 0 and 50% for CIV and EIV respectively. The positive predictive value was 93% and 86% while the negative predictive value was 0 and 50% for CIV and EIV respectively. Improvement was noted in clinical parameters (Venous Clinical Severity score; VCSS, visual analogue pain scale and grade of swelling) after IVUS and stenting following MRV investigation. For VCSS, the score improved from 6 ± 2.7 (pre-procedure) to 4 ± 2.7 (post-procedure), p=0.0001.

CONCLUSION

There is dimensional disparity between MRV and IVUS in the diagnosis of symptomatic CIVO. MRV has a high sensitivity but low specificity when compared to IVUS 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 CIVO patients.

Usefulness of Direct Computed Tomography Venography in Predicting Inflow for Venous Reconstruction in Chronic Post-thrombotic Syndrome

PURPOSE

The purpose of this paper is to assess the applicability of direct computed tomography venography (DCTV) in assessing dominant inflow vein in the femoral confluence in extensive chronic iliofemoral venous obstruction, using venography as the gold standard.

METHODS

All DCTVs performed in symptomatic patients with previous iliofemoral deep vein thrombosis subsequently submitted to venography in the period from January 2014 to August 2018 were retrospectively reviewed. Two groups were defined depending on whether the femoral vein (FV) or the deep femoral vein (DFV) was the dominant inflow on venography in order to identify predictors of DFV as dominant inflow in DCTV. Statistical analysis was performed with SPSS V25.

RESULTS

A total of 30 DCTVs and subsequent venographies were reviewed. Venography identified the FV as the dominant inflow in 18 (60%) and the DFV in 12 (40%) patients. Predictors for DFV as dominant inflow were identified as follows: larger DFV diameter 50 mm and 250 mm below lesser trochanter (8.73 ± 4.34 mm vs. 11.9 ± 3.52 mm; p = 0.043 and 5.4 ± 3.90 mm vs. 8.90 ± 2.70 mm; p = 0.011); lower FV/DFV ratio 150 mm below lesser trochanter (11.39 ± 20.01 mm vs. 1.05 ± 0.47 mm; p = 0.043); and presence of FV scarring/synechiae, collaterals and abnormal wall thickness (p = 0.003, p = 0.003 and p < 0.0001).

CONCLUSION

In cases of extensive chronic iliofemoral venous obstruction, especially when stent deployment into the DFV is entertained, the key to success is thorough pre-procedure planning focusing on choosing the access site. This study suggests DCTV is valuable in defining the dominant iliac vein inflow, but additional findings are necessary to validate these preliminary data.