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.

Catheter-Directed Thrombolysis Protocols for Deep Venous Thrombosis of the Lower Extremities-A Systematic Review and Meta-analysis.

OBJECTIVE: To summarize characteristics, complications, and success rates of different catheter-directed thrombolysis (CDT) protocols for the treatment of lower extremity deep venous thrombosis (LE-DVT). METHODS: A systematic review using electronic databases (MEDLINE, Scopus, and Web of Science) was performed to identify randomized controlled trials and observational studies related to LE-DVT treated with CDT. A random-effects model meta-analysis was performed to obtain the pooled proportions of early complications, postthrombotic syndrome (PTS), and venous patency. RESULTS: Forty-six studies met the inclusion criteria reporting 49 protocols (n = 3,028 participants). In studies that addressed the thrombus location (n = 37), LE-DVT had iliofemoral involvement in 90 ± 23% of the cases. Only four series described CDT as the sole intervention for LE-DVT, while 47% received additional thrombectomy (manual, surgical, aspiration, or pharmacomechanical), and 89% used stenting.Definition of venogram success was highly variable, being the Venous Registry Index the most used method (n = 19). Among those, the minimal thrombolysis rate (<50% lysed thrombus) was 0 to 53%, partial thrombolysis (50-90% lysis) was 10 to 71%, and complete thrombolysis (90-100%) was 0 to 88%. Pooled outcomes were 8.7% (95% confidence interval [CI]: 6.6-10.7) for minor bleeding, 1.2% (95% CI: 0.8-1.7%) for major bleeding, 1.1% (95% CI: 0.6-1.6) for pulmonary embolism, and 0.6% (95% CI: 0.3-0.9) for death. Pooled incidences of PTS and of venous patency at up to 1 year of follow-up were 17.6% (95% CI: 11.8-23.4) and 77.5% (95% CI: 68.1-86.9), respectively. CONCLUSION: Assessment of the evidence is hampered by the heterogeneity of protocols, which may be reflected in the variation of PTS rates. Despite this, CDT is a low-risk treatment for LE-DVT.

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.

[The post-thrombotic syndrome and its endovascular treatment].

Post-thrombotic syndrome (PTS) is a complication after deep venous thrombosis, causing considerable disability in affected patients. In this review, we present the aetiology, pathophysiology, risk factors and diagnosis of PTS and discuss different treatments with a special focus on endovascular treatment for iliac vein obstruction, which is documented as a safe, effective and durable treatment for severe PTS. Although treatment of PTS in Denmark currently only is based on conservative strategy, we would like to encourage, that endovascular treatment should be considered as a treatment option in these patients.

Significance of Partial or Complete Thrombosis of the Common and Deep Femoral Vein in Patients With Deep Vein Thrombosis.

OBJECTIVE: The aim was to assess the anatomical distribution of acute deep venous thrombosis (DVT) with a focus on iliofemoral DVT, and, in particular, to characterise thrombus in the common femoral vein (CFV) and the deep femoral vein (DFV). METHODS: A one year prospective study including patients older than 18 years of age with an acute first time DVT according to ultrasound examination at one of three university hospitals in Copenhagen, Denmark. Thrombus location and extent were registered and divided into five segments: calf veins; popliteal vein; femoral and deep femoral vein; common femoral vein; and iliac veins and/or the inferior vena cava. Thrombus appearance of the CFV and the DFV (partial or occlusive) was examined in detail. RESULTS: Acute DVTs were identified in 203 extremities in 200 patients (58% male). The median age of the patients was 68 years (range 19-92 years), and left-sided DVT was observed in 56%. Iliofemoral DVT was present in 54 (27.0%) patients. Thrombus involving the CFV but not the iliac veins (CFV group) was seen in 28 patients; the remaining 26 had involvement of the iliac veins (iliac group). Thrombus in the CFV was more likely to be occlusive in the iliac group than in the CFV group (77% vs. 4%; p < .001). Thrombus in the DFV was more often occlusive in the iliac group than in the CFV group (81% vs. 11%; p < .001). The DFV was free of thrombus in 12% of patients in the iliac group and in 64% of those in the CFV group. CONCLUSION: The presence of occlusive thrombus in the CFV and/or in the DFV pointed to a DVT also involving the ipsilateral iliac veins. Thrombosis of the deep leg veins extending into the CFV below the inguinal ligament was more likely to be partial in the CFV, mainly due to inflow from the DFV.

Diagnostic methods for measurement of peripheral blood flow during exercise in patients with type 2 diabetes and peripheral artery disease: a systematic review.

INTRODUCTION: Measurement of systolic ankle and to some extent toe pressure in patients suffering from combined type 2 diabetes mellitus (T2DM) and peripheral arterial disease (PAD) face several obstacles due to complex changes in the vascular bed. The aim of this review was to address the current literature on blood flow during exercise in patients with PAD and T2DM and assess the feasibility of these methods to diagnose and grade arterial insufficiency. EVIDENCE ACQUISITION: A systematic review of the PubMed and EMBASE databases, supplemented by hand searching was performed according to PRISMA guidelines. Clinical studies evaluating methods to investigate peripheral blood flow in patients with PAD and T2DM during exercise were included. EVIDENCE SYNTHESIS: In total nine eligible studies consisting of 1105 non-diabetic PAD patients, 336 diabetic PAD patients, 161 diabetic patients without PAD and 69 healthy controls were included in the review. Near-infrared spectroscopy (NIRS) was described in three studies, transcutaneous oxygen pressure measurement (TcpO2) in two and the following methods described in single studies: thermodilution, contrast enhanced ultrasound (CEUS), scintigraphy and TcpO2 in combination with ultrasound. These studies shows that patients with PAD and T2DM compared with patients with only PAD suffers different atherosclerotic lesions characterised by increased arterial stiffness and microcirculation abnormalities, not well differentiated by pressure measurement alone. Investigating patients with PAD and T2DM during exercise reveals that NIRS, TcpO2, CEUS, and scintigraphy have distinct advantages over ankle and toe-pressure. CONCLUSIONS: Using methods like NIRS, TcpO2, CEUS and scintigraphy, peripheral blood flow during exercise can be measured at a detailed level and potentially improve future severity grading in patients with combined T2DM and PAD.

Evaluation of Peak Reflux Velocities with Vector Flow Imaging and Spectral Doppler Ultrasound in Varicose Veins.

Purpose Spectral Doppler ultrasound (SDUS) is used for quantifying reflux in lower extremity varicose veins. The technique is angle-dependent opposed to the new angle-independent Vector Flow Imaging (VFI) method. The aim of this study was to compare peak reflux velocities obtained with VFI and SDUS in patients with chronic venous disease, i. e., pathological retrograde blood flow caused by incompetent venous valves. Materials and Methods 64 patients with chronic venous disease were scanned with VFI and SDUS in the great or the small saphenous vein, and reflux velocities were compared to three assessment tools for chronic venous disease. A flow rig was used to assess the accuracy and precision of the two methods. Results The mean peak reflux velocities differed significantly (VFI: 47.4 cm/s vs. SDUS: 62.0 cm/s, p<0.001). No difference in absolute precision (p=0.18) nor relative precision (p=0.79) was found. No correlation to disease severity, according to assessment tools, was found for peak reflux velocities obtained with either method. In vitro, VFI was more accurate but equally precise when compared to SDUS. Conclusion Both VFI and SDUS detected the pathologic retrograde flow in varicose veins but measured different reflux velocities with equal precision. VFI may play a role in evaluating venous disease in the future.

Respiratory variability of peak velocities in the common femoral vein estimated with vector flow imaging and Doppler ultrasound.

Respiratory variability of peak velocities (RVPV) in the common femoral vein measured with ultrasound can reveal venous outflow obstruction. Pulse wave (PW) Doppler is the gold standard for venous velocity estimation of the lower extremities. PW Doppler measurements are angle dependent, whereas vector flow imaging (VFI) can yield angle-independent measures. The hypothesis of the present study was that VFI can provide RVPV estimations without the angle dependency of PW Doppler for an improved venous disease assessment. Sixty-seven patients with symptomatic chronic venous disease were included in the study. On average, VFI measured a lower RVPV than PW Doppler (VFI: 14.11 cm/s; PW: 17.32 cm/s, p = 0.002) with a non-significant improved precision compared with PW Doppler (VFI: 21.09%; PW: 26.49%, p = 0.08). In a flow phantom, VFI had improved accuracy (p < 0.01) and equal precision compared with PW Doppler. The study indicated that VFI can characterize the hemodynamic fluctuations in the common femoral vein.