Prevention of the post thrombotic syndrome with anticoagulation: a narrative review

Comparison of anticoagulation vs mechanical thrombectomy for the treatment of iliofemoral deep vein thrombosis

OBJECTIVE

To compare the comparative effects of treatment with contemporary mechanical thrombectomy (MT) or anticoagulation (AC) on Villalta scores and post-thrombotic syndrome (PTS) incidence through 12 months in iliofemoral deep vein thrombosis (DVT).

METHODS

Patients with DVT in the Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-Directed Thrombolysis (ATTRACT) randomized trial and the ClotTriever Outcomes (CLOUT) registry were included in this analysis. Both studies evaluated the effects of thrombus removal on the incidence of PTS. Patients with bilateral DVT, isolated femoral-popliteal DVT, symptom duration of >4 weeks, or incomplete case data for matching covariates were excluded. Propensity scores were used to match patients 1:1 who received AC (from ATTRACT) with those treated with mechanical thrombectomy (from CLOUT) using nearest neighbor matching on nine baseline covariates, including age, body mass index, leg treated, provoked DVT, prior venous thromboembolism, race, sex, Villalta score, and symptom duration. Clinical outcomes, including Villalta score and PTS, were assessed. Logistic regression was used to estimate the likelihood of developing PTS at 12 months.

RESULTS

A total of 164 pairs were matched, with no significant differences in baseline characteristics after matching. There were fewer patients with any PTS at 6 months (19% vs 46%; P < .001) and 12 months (17% vs 38%; P < .001) in the MT treatment group. Modeling revealed that, after adjusting for baseline Villalta scores, patients treated with AC had significantly higher odds of developing any PTS (odds ratio, 3.1; 95% confidence interval, 1.5-6.2; P = .002) or moderate to severe PTS (odds ratio, 3.1; 95% confidence interval, 1.1-8.4; P = .027) at 12 months compared with those treated with MT. Mean Villalta scores were lower through 12 months among those receiving MT vs AC (3.3 vs 6.3 at 30 days, 2.5 vs 5.5 at 6 months, and 2.6 vs 4.9 at 12 months; P < .001 for all).

CONCLUSIONS

MT treatment of iliofemoral DVT was associated with significantly lower Villalta scores and a lower incidence of PTS through 12 months compared with treatment using AC. Results from currently enrolling clinical trials will further clarify the role of these therapies in the prevention of PTS after an acute DVT event.

Mechanical Thrombectomy vs. Pharmacomechanical Catheter Directed Thrombolysis for the Treatment of Iliofemoral Deep Vein Thrombosis: A Propensity Score Matched Exploratory Analysis of 12 Month Clinical Outcomes

OBJECTIVE

To compare thrombus removal and residual venous symptoms and signs of disease following interventional treatment of iliofemoral deep vein thrombosis (DVT) with mechanical thrombectomy (MT) and pharmacomechanical catheter directed thrombolysis (PCDT).

METHODS

Retrospective cohort analysis of propensity score matched subgroups from the multicentre prospective MT ClotTriever Outcomes registry and the PCDT arm of the randomised Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter Directed Thrombolysis trial. Patients with bilateral DVT, symptom duration greater than four weeks, isolated femoral-popliteal disease, or incomplete case data were excluded. Patients with iliofemoral DVT were propensity score matched (1:1) on 10 baseline covariables, including race, sex, age, body mass index, leg treated, prior thromboembolism, Marder score, symptom duration, provoked deep vein thrombosis status, and Villalta score. Reduction in post-procedure thrombus burden (i.e., Marder scores), assessment of venous symptoms and signs (i.e., Villalta scores) at 12 months, and healthcare resource utilisation were compared between subgroups.

RESULTS

Propensity score matching resulted in 130 patient pairs with no significant differences in baseline characteristics between the MT and PCDT groups. MT was associated with a greater reduction in Marder scores (91.0% vs. 67.7%, p < .001), and a greater proportion of patients at 12 months with no post-thrombotic syndrome (83.1% vs. 63.6%, p = .007) compared with matched patients receiving PCDT. No differences in rates of adjunctive stenting or venoplasty were identified (p = .27). Higher rates of single session treatment were seen with MT (97.7% vs. 26.9%, p < .001), which also showed shorter mean post-procedure hospital stays (1.81 vs. 3.46 overnights, p < .001), and less post-procedure intensive care unit utilisation (2.3% vs. 52.8%, p < .001).

CONCLUSION

Compared with PCDT, MT was associated with greater peri-procedural thrombus reduction, more efficient post-procedure care, and improved symptoms and signs of iliofemoral vein disease at 12 months.

TILE pilot trial study protocol: Tinzaparin Lead-in to Prevent the Post-Thrombotic syndrome study protocol

INTRODUCTION

The post-thrombotic syndrome (PTS) is a form of chronic venous insufficiency due to a prior ipsilateral deep venous thrombosis (DVT). This is a frequent complication that develops in 20%-50% of patients after a proximal DVT and is associated with significant healthcare, economic and societal consequences. In the absence of effective and well-tolerated treatment options for established PTS, effective preventative measures are needed. Anticoagulation itself reduces the risk of PTS, and low-molecular-weight heparin may reduce this further through anti-inflammatory properties targeting the initial acute inflammatory phase of DVT.

METHODS AND ANALYSIS

The Tinzaparin Lead-In to Prevent the Post-Thrombotic syndrome pilot trial is an investigator-initiated, multicentre, open-label assessor-blinded trial that will randomise patients with first acute symptomatic common femoral or iliac DVT to receive either a 3-week lead-in course of tinzaparin, followed by rivaroxaban (experimental arm) or rivaroxaban alone (control arm). Its primary objectives are to assess: (1) proportion of PTS at 6 months using the Villalta scale and (2) study feasibility, which consists of (a) the proportion of screened patients eligible for the study, (2) the proportion of eligible patients recruited and (c) the proportion of recruited patients adherent to treatment (defined as at least 80% of drug taken). This study will determine the feasibility of a subsequent larger definitive trial. Secondary outcomes include change of quality of life scores, PTS severity, global improvement, patient satisfaction, bleeding, recurrent venous thromboembolism, leg pain, death and lost to follow-up. Target recruitment will be a total of 60 participants, recruited at 5-6 centres.

ETHICS AND DISSEMINATION

Primary ethics approval was received from the Sunnybrook Health Sciences Center Research Ethics Board (approval ID 3315). Results of the study will be disseminated via peer-reviewed presentation at scientific conferences and open access publication.

TRIAL REGISTRATION NUMBER

NCT04794569.

Prevalence of Venous Thromboembolism in Intensive Care Units: A Meta-Analysis

OBJECTIVE

Venous thromboembolism (VTE) is a life threating complication in intensive care units (ICUs). This study aimed to pool the prevalence of VTE and examined the risk factors of VTE in intensive care patients worldwide.

METHODS

A systematic search in PubMed, EMBASE and Web of Science databases was performed. Studies reported that the data on the prevalence of VTE or relevant information were synthesized using a random-effects model.

RESULTS

A total of 42 studies reporting on 27,344 patients were included. The pooled prevalence of VTE was 10.0% (95% CI: 7.0-14.0%). Subgroup and metaregression analyses found that thromboprophylaxis strategy, simplified acute physiology score (SAPS II), age, study quality, sample size, malignancy, sex, spinal cord injury and injury severity score (ISS) moderated the prevalence of VTE in intensive care patients.

CONCLUSIONS

The present meta-analysis revealed a high prevalence of VTE in critically ill patients. The risk factors of VTE included thromboprophylaxis strategy, SAPS II, age, malignancy, sex, spinal cord injury and ISS. Therefore, we need to pay more attention to high-risk populations of VTE in intensive care patients.