Prothrombotic clot properties can predict venous ulcers in patients following deep vein thrombosis: a cohort study

Elevated plasma factor XI is associated with postthrombotic syndrome

INTRODUCTION

Postthrombotic syndrome (PTS), a common complication of deep vein thrombosis (DVT), is largely inflammatory by nature with contribution of prothrombotic mechanisms. The role of factor (F)XI in PTS has not been explored yet. We investigated whether elevated FXI is associated with PTS occurrence.

MATERIALS AND METHODS

We enrolled 180 consecutive patients (aged 43 ± 13 years) with first-ever DVT. After 3 months FXI levels were measured, along with inflammatory markers, thrombin generation, plasma clot permeability (Ks), clot lysis time (CLT), and fibrinolysis proteins. We assessed PTS using the Villalta score and recorded symptomatic venous thromboembolism (VTE) at a 1-year and venous ulcers at a median 53 months follow-up.

RESULTS

Baseline median FXI was 102 % [IQR 92-113 %] and showed positive association with Villalta score (R = 0.474, P < 0.001). Patients with PTS (n = 48, 26.7 %) had 16.1 % higher FXI (P < 0.001) and FXI ≥120 % occurred more often in PTS patients (odds ratio [OR] 5.55, 95 % confidence interval [CI] 2.28-13.47). There were associations of baseline FXI with Ks and CLT along with thrombin activatable fibrinolysis inhibitor (TAFI) activity, C-reactive protein, and interleukin-6, but not with fibrinogen, or thrombin generation. After age adjustment higher FXI was independently associated with PTS occurrence (OR per 1 % 1.06, 95 % CI 1.02-1.09) and VTE recurrence (OR 1.03, 95 % CI 1.01-1.06). At long-term follow-up, patients with venous ulcers had 13.6 % higher baseline FXI (P = 0.002).

CONCLUSIONS

Elevated FXI in association with inflammation and prothrombotic fibrin clot properties may contribute to the development of PTS following DVT.

Association between stroke and venous leg ulcers: A Mendelian randomization study

To investigate any potential bidirectional causal relationships between stroke and venous leg ulcers (VLUs), Mendelian randomization (MR) analyses were carried out in this study. The exposure factor was stroke, the outcome factor was VLUs. The two-sample MR study was carried out based on the online analysis platform (http://app.mrbase.org/). The association of stroke and VLUs was analysed via methods of Inverse Variance Weighted (IVW), Weighted Median, MR-Egger and weighted mode. IVW method suggested no association between stroke and VLUs ((β 1.06; SE 9.321; p = 0.9095)). Weighted median estimator (β 5.906; SE 11.99, p = 0.6223), MR-Egger (β -0.8677; SE 21.89; p = 0.9691) and weighted mode (β 9.336; SE 17.77; p = 0.6089) showed consistent results. Conversely, evidence indicating that the presence of VLUs increased the risk of stroke was lacking. According to this MR study, there is no causal connection between stroke and VLUs, which suggests that therapies targeting stroke may not be effective against VLUs.

One-Year Clinical Outcomes Following Mechanical Thrombectomy for Deep Vein Thrombosis: A CLOUT Registry Analysis

Background

Mechanical thrombectomy is a promising treatment option for deep vein thrombosis; however, long-term data are lacking. Here, we report for the first time the 1-year clinical outcomes from the completely enrolled ClotTriever Outcomes (CLOUT) registry evaluating mechanical thrombectomy with the ClotTriever System (Inari Medical).

Methods

The CLOUT registry (NCT03575364) is a prospective, multicenter, single-arm study that enrolled 500 patients with proximal lower extremity deep vein thrombosis. Prespecified 1-year outcomes include Villalta score and corresponding postthrombotic syndrome (PTS) severity, duplex ultrasound findings of patency (defined as the presence of flow with normal or partial compressibility), Revised Venous Clinical Severity Score, and quality of life (QoL).

Results

In CLOUT, the median age was 61.9 years and 50.5% of patients were women. A total of 310 patients completed the 1-year visit. The 1-year PTS rate (Villalta score ≥ 5) was 19.3% and the moderate-to-severe PTS rate (Villalta score ≥ 10) was 8.8%. Median Villalta score decreased from 9.0 (IQR, 5.0-14.0) at baseline to 1.0 (IQR, 0.0-4.0) at 1 year (P < .0001). Similar rates of PTS and moderate-to-severe PTS were observed among limbs assessed at all study time points. Patency was observed in 94.2% of limbs. Median Revised Venous Clinical Severity Score was 6.0 (IQR, 3.0-9.0) at baseline and 3.0 (IQR, 1.0-4.0) at 1 year (P < .0001). Additionally, 90.4% of patients experienced improvements in QoL.

Conclusions

One-year outcomes from the CLOUT registry demonstrate low PTS rates and preserved patency accompanied by improved symptom relief and QoL. Study follow-up through 2 years is ongoing.

Biomarkers and the post-thrombotic syndrome: A systematic review of biomarkers associated with the occurrence of the post-thrombotic syndrome after lower extremity deep venous thrombosis

INTRODUCTION

Post-thrombotic syndrome (PTS) is a frequent chronic complication of deep venous thrombosis (DVT). Biomarkers are potentially valuable clinical tools for handling PTS. The purpose of this review was to examine which biomarkers are associated with the development of PTS in adults with lower extremity DVT.

METHODS

We performed a systematic review of all English language prospective studies of biomarkers and PTS published in PubMed and EMBASE. Studies were included if diagnosing DVT by diagnostic imaging and assessing PTS by clinical scales, for example, the Villalta scale. Biomarkers of thrombophilia and pathological clot properties were not assessed. Data was reported qualitatively.

RESULTS

15 prospective studies were included. Studies varied widely in study design and methods of data analysis. Forty-six different biomarkers were examined, with seven being measured in two or more studies. The most frequently studied biomarkers were D-dimer, CRP, and IL-6. Associations between PTS and D-dimer were predominantly significant, while results on CRP and IL-6 were inconsistent. ICAM-1 was consistently associated with PTS in all studies and at all timepoints. IL-10 was significantly related to PTS development in the largest study and at all time points. Adiponectin, tPA, HRG and TAFI, MMP-1 and -8, and TIMP-1 and -2 were significantly associated with PTS in single studies.

CONCLUSION

(1) Further research on biomarkers and PTS is clearly warranted. (2) Significant differences in study designs made it difficult to draw reliable conclusions regarding individual biomarkers. We suggest the implementation of a standardized framework for the study of biomarkers and PTS, to make comparison of future studies more feasible. (3) D-dimer, ICAM-1, IL-10, MMP-1 and 8, TIMP-1, TIMP-2, and adiponectin are clinical biomarkers of particular interest to include in future studies of PTS. Large scale systemic quantitative proteomic analyses of DVT patients could help identify novel biomarkers of interest in PTS-patients.

Percutaneous mechanical thrombectomy to remove post-thrombotic obstructions and manage post-thrombotic syndrome-associated venous leg ulceration

BACKGROUND

Up to one half of patients with a diagnosis of deep vein thrombosis will develop post-thrombotic syndrome (PTS). Patients with PTS can develop venous leg ulcers (VLUs) due to post-thrombotic obstructions (PTOs) that contribute to prolonged ambulatory venous hypertension. The current treatments for PTS, which include chronic thrombus, synechiae, trabeculations, and inflow lesions, do not target PTOs, and such obstructions can affect stenting success. The aim of the present study was to determine whether removal of chronic PTOs using percutaneous mechanical thrombectomy would promote VLU resolution and positive outcomes.

METHODS

In this retrospective analysis, the characteristics and outcomes for patients with VLUs secondary to chronic PTO who were treated using the ClotTriever System (Inari Medical) between August 2021 and May 2022 were assessed. Technical success was considered the ability to cross a lesion and introduce the thrombectomy device. Clinical success was defined as a decrease of ≥1 in the severity category for the ulcer diameter using the revised venous clinical severity score (score 0, no VLU; score 1, mild VLU [size <2 cm]; score 2, moderate VLU [size 2-6 cm]; score 3, severe VLU [size >6 cm]) at the latest follow-up visit.

RESULTS

A total of 11 patients with 15 VLUs on 14 limbs were identified. Their mean age was 59.7 ± 11.8 years, and four patients (36.4%) were women. The median VLU duration was 11.0 months (interquartile range [IQR], 6.0-17.0 months), and 2 patients had VLUs secondary to a deep vein thrombosis event >40 years previously. All treatments were performed in a single session, with technical success achieved in 100% of the 14 limbs. A median of five passes (IQR, four to six passes) with the ClotTriever catheter were performed per limb. Chronic PTOs were successfully extirpated, and intraprocedural intravascular ultrasound showed effective disruption of venous synechiae and trabeculations. Stents were placed in 10 limbs (71.4%). The time to VLU resolution or the latest follow-up was 12.8 ± 10.5 weeks, and clinical success was achieved for all 15 VLUs (100%), with the revised venous clinical severity score for the ulcer diameter improving from a median of 2 (IQR, 2-2) at baseline to a median score of 0 (IQR, 0-0) at last follow-up. The VLU area had decreased by 96.6% ± 8.7%. Of the 15 VLUs, 12 (80.0%) had resolved completely, and 3 had demonstrated near-complete healing.

CONCLUSIONS

All patients showed complete or near-complete VLU healing within a few months after mechanical thrombectomy. Mechanical extirpation and interruption of chronic PTOs allowed for luminal gain and restoration of cephalad inflow. With additional investigation, mechanical thrombectomy with the study device could prove a vital component to the treatment of VLUs secondary to PTOs.

A systematic evaluation and meta-analysis of early prediction of post-thrombotic syndrome

Objective

Post-thrombotic syndrome (PTS) is the most common long-term complication in patients with deep venous thrombosis, and the prevention of PTS remains a major challenge in clinical practice. Some studies have explored early predictors and constructed corresponding prediction models, whereas their specific application and predictive value are controversial. Therefore, we conducted this systematic evaluation and meta-analysis to investigate the incidence of PTS and the feasibility of early prediction.

Methods

We systematically searched databases of PubMed, Embase, Cochrane and Web of Science up to April 7, 2023. Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of the included articles, and the OR values of the predictors in multi-factor logistic regression were pooled to assess whether they could be used as effective independent predictors.

Results

We systematically included 20 articles involving 8,512 subjects, with a predominant onset of PTS between 6 and 72 months, with a 2-year incidence of 37.5% (95% CI: 27.8-47.7%). The results for the early predictors were as follows: old age OR = 1.840 (95% CI: 1.410-2.402), obesity or overweight OR = 1.721 (95% CI: 1.245-2.378), proximal deep vein thrombosis OR = 2.335 (95% CI: 1.855-2.938), history of venous thromboembolism OR = 3.593 (95% CI: 1.738-7.240), history of smoking OR = 2.051 (95% CI: 1.305-3.224), varicose veins OR = 2.405 (95% CI: 1.344-4.304), and baseline Villalta score OR = 1.095(95% CI: 1.056-1.135). Meanwhile, gender, unprovoked DVT and insufficient anticoagulation were not independent predictors. Seven studies constructed risk prediction models. In the training set, the c-index of the prediction models was 0.77 (95% CI: 0.74-0.80) with a sensitivity of 0.75 (95% CI: 0.68-0.81) and specificity of 0.69 (95% CI: 0.60-0.77). In the validation set, the c-index, sensitivity and specificity of the prediction models were 0.74(95% CI: 0.69-0.79), 0.71(95% CI: 0.64-0.78) and 0.72(95% CI: 0.67-0.76), respectively.

Conclusions

With a high incidence after venous thrombosis, PTS is a complication that cannot be ignored in patients with venous thrombosis. Risk prediction scoring based on early model construction is a feasible option, which helps to identify the patient's condition and develop an individualized prevention program to reduce the risk of PTS.

Chronic venous ulcer resolution and post-thrombotic syndrome improvement after percutaneous mechanical thrombectomy of a 42-year-old deep vein thrombosis

Post-thrombotic syndrome (PTS) is a chronic disease affecting up to one half of patients with deep vein thrombosis. PTS symptoms range in severity, with the worst form involving the development of venous ulcers. In the present report, we have described a patient with PTS with ulceration for >40 years. A percutaneous approach with a mechanical thrombectomy extirpation device was used to remove the chronic thrombus in a single session. At >3 months of follow-up, the PTS symptoms had improved dramatically, and the ulcer had completely healed. We have demonstrated successful removal of long-standing chronic thrombus using the ClotTriever system (Inari Medical, Irvine, CA) and the management of venous ulcers resulting from debilitating PTS.

Fibrinolysis in Venous Thromboembolism

Fibrinolysis is of paramount importance in maintaining or regaining the patency of veins and pulmonary arteries obstructed by thrombi. Growing experimental and clinical evidence indicates that impaired fibrinolysis mediated by multiple complex mechanisms is involved in venous thromboembolism (VTE). Global plasma fibrin clot lysis markers, especially clot lysis time, have been reported to predict recurrent deep-vein thrombosis and pulmonary embolism. The current overview summarizes available data linking fibrinolysis to VTE and its long-term sequelae.