Rivaroxaban after Thrombolysis in Acute Iliofemoral Venous Thrombosis: A Randomized, Open-labeled, Multicenter Trial

Effectiveness and safety of early versus routine switching from low-molecular-weight heparin to maintenance therapy of rivaroxaban for acute iliofemoral vein thrombosis: a retrospective cohort study

OBJECTIVES

The anticoagulation strategy of switching to rivaroxaban after one week of initial low-molecular-weight heparin (LMWH) therapy is recommended by a guideline for the treatment of acute iliofemoral deep vein thrombosis (DVT). However, the initial rivaroxaban dose in the switching strategy, as well as the effectiveness and safety of the early switching（less than one week ）to rivaroxaban, remain inadequately substantiated. We aimed to evaluate the effectiveness and safety of early switching from LMWH to maintenance therapy of rivaroxaban (20 mg once daily) for acute iliofemoral DVT.

METHODS

A retrospective cohort study was conducted using data from patients with acute iliofemoral DVT who received initial LMWH anticoagulation followed by rivaroxaban maintenance therapy. The clinical outcomes were compared between early (LMWH course ≤ 7 days) and routine (LMWH course > 7 days) switching strategies within 3 months of initiating anticoagulation.

RESULTS

217 patients were included, 59 (27.2%) receiving early switching and 158 (72.8%) receiving routine switching. Compared with routine switching, patients with early switching had a significantly shorter hospital stay (7 days vs. 14 days, p < 0.001). The length of hospital stay was significantly positively correlated with the duration of LMWH (r = 0.762, p < 0.001). The incidences of recurrent venous thromboembolism (5.1% vs. 2.5%, p = 0.606), major bleeding (0% vs. 1.9%, p = 0.564), clinically relevant non-major bleeding (1.7 % vs. 2.5%, p = 1.000) and all-cause mortality (6.8 % vs. 2.5%, p = 0.283) were not statistically different between the two groups.

CONCLUSIONS

Direct early switching from LMWH to maintenance therapy of rivaroxaban is effective and safe for acute iliofemoral DVT.

May-Thurner syndrome: A case of extensive unprovoked left lower extremity deep vein thrombosis (DVT)

May-Thurner syndrome (MTS) also known as iliac vein compression syndrome, is a congenital anatomical variant, that results from the extrinsic compression of the left common iliac vein by the right iliac artery with resultant formation of left venous thrombosis. We report a case of a young man with recurrent unprovoked left lower extremity DVT in the setting of May Thurner syndrome who required endovascular intervention and was discharged on oral anticoagulation.

Oral direct thrombin inhibitors or oral factor Xa inhibitors versus conventional anticoagulants for the treatment of pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) is a potentially life-threatening condition in which a clot can migrate from the deep veins, most commonly in the leg, to the lungs. Conventional treatment of PE used unfractionated heparin (UFH), low molecular weight heparin (LMWH), fondaparinux, and vitamin K antagonists (VKAs). Recently, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTIs) and oral factor Xa inhibitors. DOACs have characteristics that may be favourable to conventional treatment, including oral administration, a predictable effect, no need for frequent monitoring or re-dosing, and few known drug interactions. This review reports the efficacy and safety of these drugs in the long-term treatment of PE (minimum duration of three months). This is an update of a Cochrane Review first published in 2015.  OBJECTIVES: To assess the efficacy and safety of oral DTIs and oral factor Xa inhibitors versus conventional anticoagulants for the long-term treatment of PE.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases, the World Health Organization International Clinical Trials Registry Platform and the ClinicalTrials.gov trials registers to 2 March 2022. We checked the reference lists of relevant articles for additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people with a PE confirmed by standard imaging techniques were allocated to receive an oral DTI or an oral factor Xa inhibitor compared with a conventional anticoagulant or compared with each other for the long-term treatment of PE (minimum duration three months).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were recurrent PE, recurrent venous thromboembolism (VTE), and deep vein thrombosis (DVT). Secondary outcomes were all-cause mortality, major bleeding, and health-related quality of life. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified five additional RCTs with 1484 participants for this update. Together with the previously included trials, we have included ten RCTs with a total of 13,073 participants. Two studies investigated an oral DTI (dabigatran) and eight studies investigated oral factor Xa inhibitors (three rivaroxaban, three apixaban, and two edoxaban). The studies were of good methodological quality overall.  Meta-analysis showed no clear difference in the efficacy and safety of oral DTI compared with conventional anticoagulation in preventing recurrent PE (odds ratio (OR) 1.02, 95% confidence interval (CI) 0.50 to 2.04; 2 studies, 1602 participants; moderate-certainty evidence), recurrent VTE (OR 0.93, 95% CI 0.52 to 1.66; 2 studies, 1602 participants; moderate-certainty evidence), DVT (OR 0.79, 95% CI 0.29 to 2.13; 2 studies, 1602 participants; moderate-certainty evidence), and major bleeding (OR 0.50, 95% CI 0.15 to 1.68; 2 studies, 1527 participants; moderate-certainty evidence). We downgraded the certainty of evidence by one level for imprecision due to the low number of events. There was also no clear difference between the oral factor Xa inhibitors and conventional anticoagulation in the prevention of recurrent PE (OR 0.92, 95% CI 0.66 to 1.29; 3 studies, 8186 participants; moderate-certainty evidence), recurrent VTE (OR 0.83, 95% CI 0.66 to 1.03; 8 studies, 11,416 participants; moderate-certainty evidence), DVT (OR 0.77, 95% CI 0.48 to 1.25; 2 studies, 8151 participants; moderate-certainty evidence), all-cause mortality (OR 1.16, 95% CI 0.79 to 1.70; 1 study, 4817 participants; moderate-certainty evidence) and major bleeding (OR 0.71, 95% CI 0.36 to 1.41; 8 studies, 11,447 participants; low-certainty evidence); the heterogeneity for major bleeding was significant (I2 = 79%). We downgraded the certainty of the evidence to moderate and low because of imprecision due to the low number of events and inconsistency due to clinical heterogeneity. None of the included studies measured health-related quality of life.

AUTHORS' CONCLUSIONS

Available evidence shows there is probably little or no difference between DOACs and conventional anticoagulation in the prevention of recurrent PE, recurrent VTE, DVT, all-cause mortality, and major bleeding. The certainty of evidence was moderate or low. Future large clinical trials are required to identify if individual drugs differ in effectiveness and bleeding risk, and to explore effect differences in subgroups, including people with cancer and obesity.

Oral direct thrombin inhibitors or oral factor Xa inhibitors versus conventional anticoagulants for the treatment of deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is a condition in which a clot forms in the deep veins, most commonly of the leg. It occurs in approximately one in 1000 people. If left untreated, the clot can travel up to the lungs and cause a potentially life-threatening pulmonary embolism (PE). Previously, a DVT was treated with the anticoagulants heparin and vitamin K antagonists. However, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTIs) and oral factor Xa inhibitors, which have characteristics that may be favourable compared to conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or dose adjustment and few known drug interactions. DOACs are now commonly being used for treating DVT: recent guidelines recommended DOACs over conventional anticoagulants for both DVT and PE treatment. This Cochrane Review was first published in 2015. It was the first systematic review to measure the effectiveness and safety of these drugs in the treatment of DVT. This is an update of the 2015 review.  OBJECTIVES: To assess the effectiveness and safety of oral DTIs and oral factor Xa inhibitors versus conventional anticoagulants for the long-term treatment of DVT.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 1 March 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people with a DVT, confirmed by standard imaging techniques, were allocated to receive an oral DTI or an oral factor Xa inhibitor compared with conventional anticoagulation or compared with each other for the treatment of DVT.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were recurrent venous thromboembolism (VTE), recurrent DVT and PE. Secondary outcomes included all-cause mortality, major bleeding, post-thrombotic syndrome (PTS) and quality of life (QoL). We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified 10 new studies with 2950 participants for this update. In total, we included 21 RCTs involving 30,895 participants. Three studies investigated oral DTIs (two dabigatran and one ximelagatran), 17 investigated oral factor Xa inhibitors (eight rivaroxaban, five apixaban and four edoxaban) and one three-arm trial investigated both a DTI (dabigatran) and factor Xa inhibitor (rivaroxaban). Overall, the studies were of good methodological quality. Meta-analysis comparing DTIs to conventional anticoagulation showed no clear difference in the rate of recurrent VTE (odds ratio (OR) 1.17, 95% confidence interval (CI) 0.83 to 1.65; 3 studies, 5994 participants; moderate-certainty evidence), recurrent DVT (OR 1.11, 95% CI 0.74 to 1.66; 3 studies, 5994 participants; moderate-certainty evidence), fatal PE (OR 1.32, 95% CI 0.29 to 6.02; 3 studies, 5994 participants; moderate-certainty evidence), non-fatal PE (OR 1.29, 95% CI 0.64 to 2.59; 3 studies, 5994 participants; moderate-certainty evidence) or all-cause mortality (OR 0.66, 95% CI 0.41 to 1.08; 1 study, 2489 participants; moderate-certainty evidence). DTIs reduced the rate of major bleeding (OR 0.58, 95% CI 0.38 to 0.89; 3 studies, 5994 participants; high-certainty evidence).   For oral factor Xa inhibitors compared with conventional anticoagulation, meta-analysis demonstrated no clear difference in recurrent VTE (OR 0.85, 95% CI 0.71 to 1.01; 13 studies, 17,505 participants; moderate-certainty evidence), recurrent DVT (OR 0.70, 95% CI 0.49 to 1.01; 9 studies, 16,439 participants; moderate-certainty evidence), fatal PE (OR 1.18, 95% CI 0.69 to 2.02; 6 studies, 15,082 participants; moderate-certainty evidence), non-fatal PE (OR 0.93, 95% CI 0.68 to 1.27; 7 studies, 15,166 participants; moderate-certainty evidence) or all-cause mortality (OR 0.87, 95% CI 0.67 to 1.14; 9 studies, 10,770 participants; moderate-certainty evidence). Meta-analysis showed a reduced rate of major bleeding with oral factor Xa inhibitors compared with conventional anticoagulation (OR 0.63, 95% CI 0.45 to 0.89; 17 studies, 18,066 participants; high-certainty evidence).  AUTHORS' CONCLUSIONS: The current review suggests that DOACs may be superior to conventional therapy in terms of safety (major bleeding), and are probably equivalent in terms of efficacy. There is probably little or no difference between DOACs and conventional anticoagulation in the prevention of recurrent VTE, recurrent DVT, pulmonary embolism and all-cause mortality. DOACs reduced the rate of major bleeding compared to conventional anticoagulation. The certainty of evidence was moderate or high.

Society of Interventional Radiology Position Statement on the Endovascular Management of Acute Iliofemoral Deep Vein Thrombosis

PURPOSE

To establish the updated position of the Society of Interventional Radiology (SIR) on the endovascular management of acute iliofemoral deep vein thrombosis (DVT).

MATERIALS AND METHODS

A multidisciplinary writing group with expertise in treating venous diseases was convened by SIR. A comprehensive literature search was conducted to identify studies on the topic of interest. Recommendations were drafted and graded according to the updated SIR evidence grading system. A modified Delphi technique was used to achieve consensus agreement on the recommendation statements.

RESULTS

A total of 84 studies, including randomized trials, systematic reviews and meta-analyses, prospective single-arm studies, and retrospective studies were identified and included in the review. The expert writing group developed 17 recommendations that pertain to the care of patients with acute iliofemoral DVT with the use of endovascular venous interventions.

CONCLUSIONS

SIR considers endovascular thrombus removal to be an acceptable treatment option in selected patients with acute iliofemoral DVT. Careful individualized risk assessment, high-quality general DVT care, and close monitoring during and after procedures should be provided.

Vitamin K antagonist versus novel oral anticoagulants for management of cervical artery dissection: Interactive systematic review and meta-analysis

Purpose:

Cervical artery dissection (CAD) represents a unique clinical entity with a high risk of ischemic stroke. Vitamin K antagonists (VKA) showed good efficacy in CAD management but are cumbersome to use with potentially higher bleeding rates. Novel oral anticoagulants (NOAC) are easier to use and may have similar effects but lower hemorrhagic risk. In this systematic review, we compare the efficacy of NOAC to VKA as a potential alternative treatment.

Methods:

The literature was searched on Pubmed, PMC, and Embase via API through the Nested Knowledge AutoLit software in February 2022 for studies evaluating both NOAC and VKA. Baseline characteristics, clinical and radiographic outcomes, and hemorrhagic and ischemic complications were collected for single and double-arm studies and analyzed using random-effect subgroup meta-analysis.

Findings:

Overall, 11 studies were included with 699 patients treated with VKA and 53 treated with NOAC (from three studies; two were head-to-head comparative studies). There was no statistical difference in the baseline characteristics of VKA and NOAC patients. The rates of TIA/stroke in VKA and NOAC groups were 12.3% (95% CI; 0%, 28.6%) and 5.7% (95% CI; 0%, 12.2%), respectively. Major bleeding or intracranial bleeding were comparable between groups. Lesions treated with VKA showed angiographic recanalization with a rate of 51.4% (95% CI; 35.6%, 67.1%) and for those treated with NOAC was 58.4% (95% CI; 23.9%, 93.9%). The rates of good clinical outcomes were 79.9% (95% CI; 67.6%, 92.2%) in the VKA group and 91.4% (95% CI; 78.1%, 100%) in NOAC. No statistical difference was noted among any of the outcomes between the two treatment groups.

Discussion and conclusion:

We highlighted comparable efficacy and safety of NOAC to VKA for stroke prevention in CAD. Further head-to-head studies are warranted to validate these results.

Predictive modeling for COVID-19 readmission risk using machine learning algorithms

Introduction

The COVID-19 pandemic overwhelmed healthcare systems with severe shortages in hospital resources such as ICU beds, specialized doctors, and respiratory ventilators. In this situation, reducing COVID-19 readmissions could potentially maintain hospital capacity. By employing machine learning (ML), we can predict the likelihood of COVID-19 readmission risk, which can assist in the optimal allocation of restricted resources to seriously ill patients.

Methods

In this retrospective single-center study, the data of 1225 COVID-19 patients discharged between January 9, 2020, and October 20, 2021 were analyzed. First, the most important predictors were selected using the horse herd optimization algorithms. Then, three classical ML algorithms, including decision tree, support vector machine, and k-nearest neighbors, and a hybrid algorithm, namely water wave optimization (WWO) as a precise metaheuristic evolutionary algorithm combined with a neural network were used to construct predictive models for COVID-19 readmission. Finally, the performance of prediction models was measured, and the best-performing one was identified.

Results

The ML algorithms were trained using 17 validated features. Among the four selected ML algorithms, the WWO had the best average performance in tenfold cross-validation (accuracy: 0.9705, precision: 0.9729, recall: 0.9869, specificity: 0.9259, F-measure: 0.9795).

Conclusions

Our findings show that the WWO algorithm predicts the risk of readmission of COVID-19 patients more accurately than other ML algorithms. The models developed herein can inform frontline clinicians and healthcare policymakers to manage and optimally allocate limited hospital resources to seriously ill COVID-19 patients.

Deep Learning for Accurate Segmentation of Venous Thrombus from Black-Blood Magnetic Resonance Images: A Multicenter Study

Objective

Deep vein thrombosis (DVT) is the third-largest cardiovascular disease, and accurate segmentation of venous thrombus from the black-blood magnetic resonance (MR) images can provide additional information for personalized DVT treatment planning. Therefore, a deep learning network is proposed to automatically segment venous thrombus with high accuracy and reliability.

Methods

In order to train, test, and external test the developed network, total images of 110 subjects are obtained from three different centers with two different black-blood MR techniques (i.e., DANTE-SPACE and DANTE-FLASH). Two experienced radiologists manually contoured each venous thrombus, followed by reediting, to create the ground truth. 5-fold cross-validation strategy is applied for training and testing. The segmentation performance is measured on pixel and vessel segment levels. For the pixel level, the dice similarity coefficient (DSC), average Hausdorff distance (AHD), and absolute volume difference (AVD) of segmented thrombus are calculated. For the vessel segment level, the sensitivity (SE), specificity (SP), accuracy (ACC), and positive and negative predictive values (PPV and NPV) are used.

Results

The proposed network generates segmentation results in good agreement with the ground truth. Based on the pixel level, the proposed network achieves excellent results on testing and the other two external testing sets, DSC are 0.76, 0.76, and 0.73, AHD (mm) are 4.11, 6.45, and 6.49, and AVD are 0.16, 0.18, and 0.22. On the vessel segment level, SE are 0.95, 0.93, and 0.81, SP are 0.97, 0.92, and 0.97, ACC are 0.96, 0.94, and 0.95, PPV are 0.97, 0.82, and 0.96, and NPV are 0.97, 0.96, and 0.94.

Conclusions

The proposed deep learning network is effective and stable for fully automatic segmentation of venous thrombus on black blood MR images.

Safety and Efficacy of Rivaroxaban for Inferior Vena Cava Thrombosis after Successful Catheter-Directed Thrombolysis

Rivaroxaban use for inferior vena cava (IVC) thrombosis after successful catheter-directed thrombolysis (CDT) is rarely reported. This study aimed at investigating the safety and efficacy of rivaroxaban for IVC thrombosis after CDT. The clinical data on 38 consecutive patients with IVC thrombosis (68% male; mean age, 51.5 ± 16.5), who received rivaroxaban after CDT between July 2017 and January 2020, were retrospectively analyzed in this study. Safety and efficacy of rivaroxaban (bleedings and recurrent venous thromboembolism), cumulative prevalence of post-thrombotic syndrome (PTS), primary patency, clinically driven target lesion revascularization rate, and other adverse events including all-cause mortality and vascular events (systemic embolism, acute coronary syndrome, ischemic stroke, and transient ischemic attack) were retrospectively analyzed. Of the 38 patients who received rivaroxaban for IVC thrombosis after CDT, 27 (71%) had an anticoagulant duration of 6 months and 11 patients (29%) of more than 6 months. Four patients (10%) suffered recurrent thrombosis. No patient suffered major bleeding, while clinically relevant nonmajor bleeding occurred in two (5%) patients. The cumulative prevalence of PTS was 18% (7/38) during the 12 months follow-up period. Primary patency at 1, 3, 6, and 12 months was 97, 92, 90, and 90%, respectively. According to follow-up data, the clinically driven target lesion revascularization of this study was 10%. Cardiovascular events and mortality did not occur in any patient during the study period. Rivaroxaban for IVC thrombosis after successful CDT can be safe and effective.

Risk of intracranial hemorrhage with direct oral anticoagulants: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

We performed a systematic review and meta-analysis to compare the risk of intracranial hemorrhage (ICH) between direct oral anticoagulants (DOACs) and other antithrombotic drugs in detail across all diseases.

METHODS

PubMed, EMBASE, Web of Science, and the Cochrane Library were searched for relevant randomized controlled trials (RCTs). Heterogeneity was examined using the I² statistic. Risk ratio (RR) and 95% confidence interval (CI) were calculated using random-effects meta-analysis.

RESULTS

Fifty-five RCTs were included in this meta-analysis. Compared with vitamin K antagonists (VKAs), dabigatran reduced the risk of ICH by 60% (RR 0.40; 95% CI 0.28-0.57), apixaban by 57% (RR 0.43; 95% CI 0.31-0.58), edoxaban by 56% (RR 0.44; 95% CI 0.29-0.67) and rivaroxaban by 41% (RR 0.59; 95%CI 0.44-0.80). Compared with low-molecular-weight heparins (LMWHs), apixaban, edoxaban and rivaroxaban had a similar risk of ICH. Compared with aspirin, dabigatran and apixaban had a similar risk of ICH, while rivaroxaban posed an increased risk of ICH (RR 2.12; 95% CI 1.31-3.44). For secondary prevention stroke, DOACs reduced the risk of ICH by 46% compared with warfarin (RR 0.54; 95% CI [0.42-0.70]) and had a similar risk of ICH compared with aspirin.

CONCLUSION

All DOACs had a lower risk of ICH than VKAs. In terms of the risk of ICH, DOACs were overall as safe as LMWHs, and apixaban and dabigatran were as safe as aspirin, but rivaroxaban was not. For secondary prevention stroke, the risk of ICH with DOACs was overall lower than warfarin and similar to aspirin, but it should be noted that compared with aspirin, rivaroxaban may increase the risk of ICH. This is the first pair-wise meta-analysis that compares the risk of ICH between DOACs and other antithrombotic drugs in detail across all diseases, which may have certain significance for patients with high risk of ICH to choose antithrombotic drugs in clinical practice.