External Validation of a Venous Thromboembolic Risk Score for Cancer Outpatients with Solid Tumors: The COMPASS-CAT Venous Thromboembolism Risk Assessment Model

Risk of Venous Thromboembolism by Cancer Type: A Network Meta-Analysis

Patients with cancer have an increased risk of venous thromboembolism (VTE). Comparing tumor-specific VTE risk is complicated by factors such as surgery, disease stage, and chemotherapy. Network meta-analysis (NMA) using cancer types as network nodes enabled us to estimate VTE rates by leveraging comparisons across cancer types while adjusting for baseline VTE risk in individual studies. This study was conducted to estimate the risk of VTE by cancer type and factors influencing VTE risk. The Embase, MEDLINE, and Cochrane Library repositories were systematically searched to identify clinical trials and observational studies published from 2005 to 2022 that assessed the risk of primary cancer-related VTE among two or more distinct cancer types. Studies with similar cancer populations and study methods reporting VTE occurring within 1 year of diagnosis were included in the NMA. Relative VTE rates across cancer types were estimated with random-effects Bayesian NMAs. Absolute VTE rates were calculated from these estimates using the average VTE incidence in lung cancer (the most frequently reported type) as the "anchor." From 2,603 records reviewed, 30 studies were included in this NMA. The general network described 3,948,752 patients and 18 cancer types: 3.1% experienced VTE within 1 year of diagnosis, with cancer-specific rates ranging from 0.7 to 7.4%. Consistent with existing VTE risk prediction tools, pancreatic cancer was associated with higher-than-average VTE risk. Other cancer types with high VTE risk were brain and ovarian cancers. The relative rankings of VTE risk for certain cancers changed based on disease stage and/or receipt of chemotherapy or surgery.

ABO Blood Group and the Risk of Thrombosis in Cancer Patients: A Mini-Review

Cancer-associated thrombosis (CT), especially venous thromboembolism (VTE), is a common occurrence with several factors contributing to a wide diversity in thrombosis risk. The association between ABO blood groups and the risk for CT has been examined in various studies, with non-O blood type associated with an increased thrombosis risk; however, these studies have reported varying results with recognized limitations. ABO blood groups are known to be implicated in hemostasis, in an association mediated through von Willebrand factor (VWF). In this narrative review, we aim to summarize the current knowledge surrounding the role of ABO blood groups in VTE, with a particular focus on the role of VWF and other contributing risk factors on VTE occurrence. We found evidence from literature for the impact of ABO blood groups in determining the risk of VTE in healthy populations, with a limited number of studies examining this effect in cancer patients. Additionally, research on the impact of ABO on different cancer types lacks rigor, particularly in regard to other risk factors. Overall, most studies showed strong association of increased risk of VTE amongst cancer patients with non-O blood groups and increased VWF levels. This association was weaker in a few studies. Further research is needed before a solid conclusion can be made about the ABO or ABO-VWF-mediated hypercoagulability and VTE risk in various cancers. These studies will help determine if ABO typing can be an added biomarker to improve VTE risk assessment models in cancer patients.

Models for predicting venous thromboembolism in ambulatory patients with lung cancer: A systematic review and meta-analysis

AIMS

The incidence of venous thromboembolism (VTE) in patients with lung cancer is relatively high, and risk stratification models are vital for the targeted application of thromboprophylaxis. We aimed to review VTE risk prediction models that have been developed in patients with lung cancer and evaluated their performance.

METHODS AND RESULTS

Twenty-four eligible studies involving 123,493 patients were included. The pooled incidence of VTE within 12 months was 11 % (95 % CI 8 %-14 %). With the identified four VTE risk assessment tools, meta-analyses did not show a significant discriminatory capability of stratifying VTE risk for Khorana, PROTECHT and CONKO scores. The pooled sensitivity and specificity of the Khorana score were 24 % (95 % CI 11 %-44 %) and 84 % (95 % CI 73 %-91 %) at the 3-point cut-off, and 43 % (95 % CI 35 %-52 %) and 61 % (95 % CI 52 %-69 %) at the 2-point cut-off. However, a COMPASS-CAT score of ≥ 7 points indicated a significantly high VTE risk, with a RR of 4.68 (95 % CI 1.05-20.80).

CONCLUSIONS

The Khorana score lacked discriminatory capability in identifying patients with lung cancer at high VTE risk, regardless of the cut-off value. The COMPASS-CAT score had better performance, but further validation is needed. The results indicate the need for robust VTE risk assessment tools specifically designed and validated for lung cancer patients. Future research should include relevant biomarkers as important predictors and consider the combined use of risk tools. PROSPERO registration number: CRD42021245907.

Novel Insights in Venous Thromboembolism Risk Assessment Methods in Ambulatory Cancer Patients: From the Guidelines to Clinical Practice

Many cancer patients will experience venous thromboembolism (VTE) at some stage, with the highest rate in the initial period following diagnosis. Novel cancer therapies may further enhance the risk. VTE in a cancer setting is associated with poor prognostic, a decreased quality of life, and high healthcare costs. If thromboprophylaxis in hospitalized cancer patients and perioperative settings is widely accepted in clinical practice and supported by the guidelines, it is not the same situation in ambulatory cancer patient settings. The guidelines do not recommend primary thromboprophylaxis, except in high-risk cases. However, nowadays, risk stratification is still challenging, although many tools have been developed. The Khrorana score remains the most used method, but it has many limits. This narrative review aims to present the current relevant knowledge of VTE risk assessment in ambulatory cancer patients, starting from the guideline recommendations and continuing with the specific risk assessment methods and machine learning models approaches. Biomarkers, genetic, and clinical features were tested alone or in groups. Old and new models used in VTE risk assessment are exposed, underlining their clinical utility. Imaging and biomolecular approaches to VTE screening of outpatients with cancer are also presented, which could help clinical decisions.

Construction and Validation of a Nomogram to Predict the Postoperative Venous Thromboembolism Risk in Patients with HGSOC

Venous thromboembolism (VTE) is a common complication in patients with high-grade serous ovarian cancer (HGSOC) after surgery. This study aims to establish a comprehensive risk assessment model to better identify the potential risk of postoperative VTE in HGSOC. Clinical data from 587 HGSOC patients who underwent surgical treatment were retrospectively collected. Univariate and multivariate logistic regression analyses were performed to identify independent factors influencing the occurrence of postoperative VTE in HGSOC. A nomogram model was constructed in the training set and further validated in the verification set. Logistic regression identified age (odds ratio [OR] = 1.063, P = .002), tumor size (OR = 3.815, P < .001), postoperative transfusion (OR = 5.646, P = .001), and postoperative D-dimer (OR = 1.246, P = .003) as independent risk factors for postoperative VTE in HGSOC patients. A nomogram was constructed using these factors. The receiver operating characteristic curve showed an area under the curve (AUC) of 0.840 (95% confidence interval [CI]: 0.782, 0.898) in the training set and 0.793 (95% CI: 0.704, 0.882) in the validation set. The calibration curve demonstrated a good consistency between model predictions and actual results. The decision curve analysis indicated the model benefits at a threshold probability of less than 70%. A nomogram predicting postoperative VTE in HGSOC was established and validated. This model will assist clinicians in the early identification of high-risk patients, enabling the implementation of appropriate preventive measures.

Development and Validation of a Modified Khorana Score for Predicting Venous Thromboembolism in Newly Diagnosed Stage IV Lung Cancer

We aimed to establish an effective model to identify metastatic lung cancer patients at high risk of venous thromboembolism (VTE). Patients diagnosed with stage IV lung cancer from January 2011 to June 2019 were included in the development cohort; those recruited from July 2019 to June 2021 were included in the validation cohort. Univariable and multivariable analyses determined the risk factors for VTE. Then we assessed the value for predicting VTE of the Khorana score and modified Khorana score in these two cohorts; 575 patients were included in the development cohort, and 202 patients in the validation cohort. Adenocarcinoma, D-dimer, and the Khorana score were independent risk factors for VTE. In the development cohort, the area under the receiver operating characteristic curve (AUC) of the Khorana score in patients with newly diagnosed stage IV lung cancer was 0.598 (95% CI, 0.512-0.684). The AUC of the modified Khorana score was 0.747 (95% CI, 0.689-0.805). The difference was statistically significant (P <.001). The AUC of the modified Khorana score in the validation cohort was 0.763 (95% CI, 0.661-0.865). The modified Khorana score is more able to accurately predict VTE in patients with newly diagnosed stage IV lung cancer than the Khorana score.

Primary prevention of cancer-associated venous thrombosis: Rationale and challenges in clinical practice

Cancer-associated venous thrombosis (CAT) is a common, multifactor event known to complicate the course of cancer and jeopardize a patient's prognosis. The current guidelines regarding the prevention of CAT are sometimes considered insufficiently precise about specific situations, or are poorly applied. The expected benefits of thromboprophylaxis are balanced by the risk of major bleeding induced by anticoagulation, which implies a need to accurately identify ambulatory patients at high risk of thrombosis or hemorrhage. The Khorana score is commonly used for this, but is limited by the non-reproducibility of predicted performance across cancer types, and by the fact that antitumor treatment and cardiovascular risks are not included. The COMPASS-CAT score, which includes those two aspects, was found to be a more accurate predictor of venous thromboembolism in patients with lung cancer, and to better distinguish between patients at low or high risk of thrombosis. The frailty of patients with cancer is also a major issue, and should be taken into account when thromboprophylaxis is considered. According to current guidelines, CAT prophylaxis should be considered for hospitalized patients, those for whom surgery is scheduled, or those with pancreatic cancers. In ambulatory patients, decisions should be made according to patient, cancer and antitumoral treatment characteristics. Low molecular weight heparin is the gold standard of CAT prophylaxis. Despite increased risks of bleeding or drug-drug interactions in cancer patients, direct oral anticoagulants could be alternate options for high-risk ambulatory patients that should be accompanied by a careful global analysis of benefits, harms, and patient preferences.

[Prophylaxis and management of cancer-associated thrombosis: Practical issues about anticoagulant use]

Cancer-associated thrombosis (CAT) is a common complication resulting from various vascular mechanisms related to cancer, antitumoral therapy and patient status, and is associated with a poor prognosis. Anticoagulants recommended for CAT treatment or prevention mainly include low molecular weight heparin (LMWH) and direct oral anticoagulants (DOACs). Regarding thromboprophylaxis, a situation for which LMWH is a preferred option due to a lower risk of hemorrhage especially in patients with unresected gastro-intestinal and genito-urinary malignancies, the identification of patients at risk is a major issue. For patients with established CAT, the main issue is the choice of the most appropriate anticoagulant therapy. Because of the convenience of oral formulation, DOACs are an attractive option, and their efficacy has been shown in randomized trials. However, such studies are limited by selection biases, which make the analyzed population not representative of the real-life setting, as for instance cancers associated with a high risk of hemorrhage, or antitumoral therapies (e.g., tyrosine kinase inhibitors) known to interact with DOACs and then modifying their bioavailability. Caution associated with DOAC use is highlighted by most updated guidelines that recommend a case-by-case-based approach. The aim of the present paper is to help the oncologists make the most appropriate decision regarding the choice of anticoagulant therapy in a context of thromboprophylaxis or established CAT management in a patient with a solid tumor. The main issues are addressed through key practical questions, the answers of which are based on the current guidelines and additional published data or expert opinions.

The Saudi Consensus for the Management of Cancer-Associated Thromboembolism: A Modified Delphi-Based Study

Background  Cancer is a well-known risk factor of preventable thromboembolic disease. This study aims to provide guidance on the prevention and management of cancer-associated thrombosis (CT) that tailors prophylactic and therapeutic options for medical and surgical oncology patients presenting to health care settings in Saudi Arabia. Methods  The present consensus was developed in concordance with the modified Delphi-based approach, which incorporates a face-to-face meeting between two voting rounds to gain experts' feedback on the proposed statements. All experts were either oncologists, hematologists, or hemato-oncologist with an active clinical and research profile in hemato-oncology. Results  The experts highlighted that the comparatively high incidence of inherited thrombophilia among the Saudi population may account for a higher CT burden in the Kingdom than in other parts of the world. However, due to the lack of literature that assesses CT in Saudi Arabia, primary venous thromboembolism prophylaxis should be tailored according to a valid risk assessment of cancer patients and should be implemented in routine practice. For hospitalized medical oncology patients, the experts agreed that prophylaxis with low-molecular-weight heparin (LMWH) should be offered, regardless of the presence of acute illness. For ambulatory medical oncology patients, LMWH or direct oral anticoagulants (DOACs) prophylaxis should be offered for high-risk patients. Concerning surgical patients, they agreed that all oncology patients undergoing surgery should be offered thromboprophylaxis. In terms of secondary prophylaxis, the experts recommended continuing a prophylactic dose of anticoagulant (LMWH or DOAC), for an appropriate period depending on the cancer type and stage. Finally, they also provided a set of statements on management of CT in Saudi Arabia. Conclusion  The present modified Delphi-based study combined the best available evidence and clinical experience with the current health care policies and settings in Saudi Arabia to build a consensus statement on the epidemiology, prevention, and management of CT.

Interleukin-10 levels and the risk of thromboembolism according to COMPASS-Cancer associated thrombosis score in breast cancer patients prior to undergoing doxorubicin-based chemotherapy

Venous thromboembolism (VTE) is an important cause of morbidity/mortality in cancer patients, and COMPASS-CAT score must be used to VTE-risk prediction. There is a relationship between cytokines and thrombus formation and/or resolution. This study aimed to investigate the VTE risk and cytokines level in breast cancer patients prior to chemotherapy with doxorubicin (DOXO). Eighty women with breast cancer and indication for DOXO treatment were selected. TNF, IL-1β, IL-6, and IL-10 were measured after the diagnosis and immediately before DOXO treatment. All 80 patients presented a high risk for VTE when evaluated by COMPASS-CAT model (score ≥7). A positive correlation was observed between IL-10 plasma levels and VTE risk score. Our data showed that higher IL-10 levels before chemotherapy are associated to increased risk of VTE in breast cancer patients. This finding suggests that IL-10 levels and the combination with COMPASS-CAT score could be good markers to predict increased risk of VTE in these patients.

Optimal authoritative risk assessment score of Cancer-associated venous thromboembolism for hospitalized medical patients with lung Cancer

Background

Cancer-associated venous thromboembolism (VTE) is common in patients with primary lung cancer. It has been understudied which authoritative risk assessment score of cancer-associated VTE is optimal for the assessment of VTE development in hospitalized medical patients with lung cancer.

Methods

Patients with lung cancer who had undergone computed tomography pulmonary angiography (CTPA), compression ultrasonography (CUS) of lower and upper extremities, and/or planar ventilation/perfusion (V/Q) scan to confirm the presence or absence of VTE during a medical hospitalization were retrospectively reviewed. Based on the actual prevalence of VTE among all patients, the possibility of VTE were reassessed with the Khorana score, the PROTECHT score, the CONKO score, the ONKOTEV score, the COMPASS-CAT score, and the CATS/MICA score, to compare their assessment accuracy for VTE development.

Results

A total of 1263 patients with lung cancer were incorporated into the final analysis. With respect to assessment efficiency for VTE occurrence, the scores with adjusted agreement from highest to lowest were the ONKOTEV score (78.6%), the PROTECHT score (73.4%), the CONKO score (72.1%), the COMPASS-CAT score (71.7%), the Khorana score (70.9%), and the CATS/MICA score (60.3%). The ONKOTEV score had the highest Youden index which was 0.68, followed by the PROTECHT score (0.58), the COMPASS-CAT score (0.56), the CONKO score (0.55), the Khorana score (0.53), and the CATS/MICA score (0.23).

Conclusions

Among the Khorana score, the PROTECHT score, the CONKO score, the ONKOTEV score, the COMPASS-CAT score, and the CATS/MICA score which are approved by authoritative guidelines, the ONKOTEV score is optimal for the assessment of VTE development in hospitalized medical patients with lung cancer.

Advances in the Prediction and Risk Assessment of Lung Cancer-Associated Venous Thromboembolism

According to the most recent data from the National Cancer Center, venous thromboembolism (VTE) has unsurprisingly become one of the most common complications in lung cancer. VTE not only interferes with the equilibrium of the clotting system but it also affects tumor progression and prognosis. For the identification of high-risk patients, many clinical risk assessment models have been developed and validated based on the risk factors found in previous studies. In this review, we will summarize advances in prediction and risk assessment of VTE, with a focus on early diagnosis and therapy, reduction of mortality, and the burden of medical costs in lung cancer patients.

Cancer-Associated Thrombosis: A Clinical Scoping Review of the Risk Assessment Models Across Solid Tumours and Haematological Malignancies

Cancer-associated thrombosis (CAT) is a leading cause of death in cancer patients receiving outpatient chemotherapy. The latest guidelines emphasize stratifying the patients in terms of CAT risks periodically. Multiple risk assessment models (RAMs) were developed to classify patients and guide thromboprophylaxis to high-risk patients. This study aimed to discuss and highlight different RAMs across various malignancy types with their related advantages and disadvantages. A scoping review was conducted using predefined search terms in three scientific databases, including Google Scholar, Science Direct, and PubMed. The search for studies was restricted to original research articles that reported risk assessment models published in the last thirteen years (between 2008 and 2021) to cover the most recently published evidence following the development of the principal risk assessment score in 2008. Data charting of the relevant trials, scores, advantages, and disadvantages were done iteratively considering the malignancy type. Of the initially identified 1115 studies, 39 studies with over 67,680 patients were included in the review. In solid organ malignancy, nine risk assessment scores were generated. The first and most known Khorana risk score still offers the best available risk assessment model when used for high-risk populations with a threshold of 2 and above. However, KRS has a limitation of failure to stratify low-risk patients. The COMPASS-CAT score showed the best performance in the lung carcinoma patients who have a higher prevalence of thrombosis than other malignancy subtypes. In testicular germ cell tumours, Bezan et al RAM is a validated good discriminatory RAM for this malignancy subtype. CAT in haematological malignancy seems to be under-investigated and has multiple disease-related, and treatment-related confounding factors. AL-Ani et al score performed efficiently in acute leukemia. In multiple myeloma, both SAVED and IMPEDED VTE scores showed good performance. Despite the availability of different disease-specific scores in lymphoma-related thrombosis, the standard of care needs to be redefined.

Risk Factors and Prediction Models for Venous Thromboembolism in Ambulatory Patients with Lung Cancer

Venous thromboembolism (VTE) is a significant cause of mortality in patients with lung cancer. Despite the availability of a wide range of anticoagulants to help prevent thrombosis, thromboprophylaxis in ambulatory patients is a challenge due to its associated risk of haemorrhage. As a result, anticoagulation is only recommended in patients with a relatively high risk of VTE. Efforts have been made to develop predictive models for VTE risk assessment in cancer patients, but the availability of a reliable predictive model for ambulate patients with lung cancer is unclear. We have analysed the latest information on this topic, with a focus on the lung cancer-related risk factors for VTE, and risk prediction models developed and validated in this group of patients. The existing risk models, such as the Khorana score, the PROTECHT score and the CONKO score, have shown poor performance in external validations, failing to identify many high-risk individuals. Some of the newly developed and updated models may be promising, but their further validation is needed.

Overview of risk assessment models for venous thromboembolism in ambulatory patients with cancer

A B S T R A C T Important progress has been made in the development of risk assessment models (RAM) for the identification of outpatients on anticancer treatment at risk of venous thromboembolism (VTE). Since the breakthrough publication of the original Khorana risk score (KRS) more than 10 years ago, a new generation of KRS-based scores have been developed, including the Vienna Cancer and Thrombosis Study, PROTECHT, CONKO, ONCOTEV, TicOnco and the CATS/MICA score. Among these the CATS/MICA score showed that a simplified score composed of only two calibrated predictors, the type of cancer and the D-dimer levels, offers a user-friendly tool for the evaluation of cancer-associated thrombosis (CAT) risk. The COMPASS-CAT score is the first that introduced a more synthetic approach of risk evaluation by combining cancer-related predictors with patient comorbidity in a score which is designed for the types of cancer frequently seen in the community (i.e. breast, lung colon or ovarian cancers) and has been externally validated in independent studies. The Throly score is registered as part of the same group as it has a similar structure to the COMPASS-CAT score and is applicable in patients with lymphoma. The incorporation of specific biomarkers of hypercoagulability to the RAM for CAT offers the possibility to perform a precision medicine approach in the prevention of CAT. The improvement of RAM for CAT with artificial intelligence methodologies and deep learning techniques is the challenge in the near future.

Risk Assessment Models for Thrombosis and Anticoagulant-Related Bleeding in Ambulatory Cancer Patients

Cancer patients have a high risk of developing venous thromboembolism and arterial thrombosis, along with an increased risk of anticoagulant-related bleeding with primary and secondary prophylaxis of cancer-associated thrombosis. Decisions on initiation, dosing, and duration of anticoagulant therapy for prevention and treatment of cancer-associated thrombosis are challenging, as clinicians have to balance patients' individual risk of (recurrent) thrombosis against the risk of bleeding complications. For this purpose, several dedicated risk assessment models for venous thromboembolism in cancer patients have been suggested. However, most of these scores perform poorly and have received limited to no validation. For bleeding and arterial thrombosis, no risk scores have been developed specifically for cancer patients, and treatment decisions remain based on clinical gestalt and rough and unstructured estimation of the risks. The aims of this review are to summarize the characteristics and performance of risk assessment scores for (recurrent) venous thromboembolism and discuss available data on risk assessment for bleeding and arterial thrombosis in the cancer population. This summary can help clinicians in daily practice to make a balanced decision when considering the use of risk assessment models for cancer-associated venous thromboembolism. Future research attempts should aim at improving risk assessment for arterial thrombosis and anticoagulant-related bleeding in cancer patients.

High discrepancy in thrombotic events in non-small cell lung cancer patients with different genomic alterations

Background

Acute complications, such as venous thromboembolism (VTE), are common in patients with advanced severe lung cancers. However, current VTE risk scores cannot adequately identify high-risk patients with non-small cell lung cancer (NSCLC). The study proposed to elucidated the incidence of thromboembolism (TE) in patients with different oncogenic aberrations and the impact of these aberrations on the efficacy of targeted therapy in patients with NSCLC.

Methods

A systemic review was conducted in Web of Science, PubMed, Embase and the Cochrane Library to evaluate the incidence of TE in different molecular subtypes of NSCLC. Data from patients diagnosed of advanced NSCLC who harboring anaplastic lymphoma kinase (ALK) or ROS proto-oncogene 1 receptor tyrosine kinase (ROS1) rearrangements since 2016 to 2019 were also retrospectively collected. A meta-analysis with random-effects model, sensitivity analysis and publication bias were performed. The principal summary measure was incidence of thrombotic events in NSCLC patients. And the efficacy of tyrosine kinase inhibitor (TKI) therapy was compared between the two subgroups.

Results

A total of 5,767 cases from 20 studies were included in the analysis of the incidence of thrombosis in patients with different oncogenic alterations. The pooled analysis showed a higher risk of thrombosis in ROS1-fusion types (41%, 95% CI: 35-47%) and ALK-fusion types (30%, 95% CI: 24-37%) than in EGFR-mutation (12%, 95% CI: 8-17%), KRAS-mutation (25%, 95% CI: 13-50%), and wild-type (14%, 95% CI: 10-20%) cases. A high prevalence of thrombosis (ALK: 24.4%; ROS1: 32.6%) was observed in the Shanghai Pulmonary Hospital (SPH) cohort of 224 patients with ALK or ROS1 fusion. Furthermore, patients with embolism had significantly shorter progression-free survival (PFS) after TKI therapy than those without embolism, both in the ALK+ cohort (5.6 vs. 12.9 months, P<0.0001) and in the ROS1+ cohort (9.6 vs. 17.6 months, P=0.0481).

Conclusions

NSCLC patients with ALK/ROS1 rearrangements are more likely to develop thrombosis than patients with other oncogenic alterations. Thrombosis may also be associated with an inferior response and PFS after TKI therapy.

Venous Thromboembolism in Cancer Patients Undergoing Chemotherapy: Risk Factors and Prevention

Ambulatory cancer patients undergoing chemotherapy are at a substantial risk for venous thromboembolism (VTE) over the course of therapy and beyond it. Factors accounting for this risk include the activation of extrinsic and intrinsic coagulation pathways, platelet activation, impaired fibrinolysis, use of catheters, infusion of blood products, and thrombogenic potential of several chemotherapeutic drugs. A few stratification models can help identify patients at a higher risk of chemotherapy-associated VTE, who may benefit from preventive strategies. Although low-molecular-weight heparins (LMWHs) effectively reduce the risk of VTE, current guidelines recommend against their routine use. Based on the results of recent randomized controlled clinical trials, the administration of prophylactic doses of the novel direct oral anticoagulants (DOACs) to ambulatory cancer patients undergoing chemotherapy has the potential to offer an effective and safe protection against VTE, obviating the inconveniences of heparins. Except for patients in whom the novel drugs are unsuitable or are contraindicated, in all other patients LMWHs should be replaced by low-dose DOACs.