Safety of treating acute pulmonary embolism at home: an individual patient data meta-analysis.

BACKGROUND AND AIMS: Home treatment is considered safe in acute pulmonary embolism (PE) patients selected by a validated triage tool (e.g. simplified PE severity index score or Hestia rule), but there is uncertainty regarding the applicability in underrepresented subgroups. The aim was to evaluate the safety of home treatment by performing an individual patient-level data meta-analysis. METHODS: Ten prospective cohort studies or randomized controlled trials were identified in a systematic search, totalling 2694 PE patients treated at home (discharged within 24 h) and identified by a predefined triage tool. The 14- and 30-day incidences of all-cause mortality and adverse events (combined endpoint of recurrent venous thromboembolism, major bleeding, and/or all-cause mortality) were evaluated. The relative risk (RR) for 14- and 30-day mortalities and adverse events is calculated in subgroups using a random effects model. RESULTS: The 14- and 30-day mortalities were 0.11% [95% confidence interval (CI) 0.0-0.24, I2 = 0) and 0.30% (95% CI 0.09-0.51, I2 = 0). The 14- and 30-day incidences of adverse events were 0.56% (95% CI 0.28-0.84, I2 = 0) and 1.2% (95% CI 0.79-1.6, I2 = 0). Cancer was associated with increased 30-day mortality [RR 4.9; 95% prediction interval (PI) 2.7-9.1; I2 = 0]. Pre-existing cardiopulmonary disease, abnormal troponin, and abnormal (N-terminal pro-)B-type natriuretic peptide [(NT-pro)BNP] at presentation were associated with an increased incidence of 14-day adverse events [RR 3.5 (95% PI 1.5-7.9, I2 = 0), 2.5 (95% PI 1.3-4.9, I2 = 0), and 3.9 (95% PI 1.6-9.8, I2 = 0), respectively], but not mortality. At 30 days, cancer, abnormal troponin, and abnormal (NT-pro)BNP were associated with an increased incidence of adverse events [RR 2.7 (95% PI 1.4-5.2, I2 = 0), 2.9 (95% PI 1.5-5.7, I2 = 0), and 3.3 (95% PI 1.6-7.1, I2 = 0), respectively]. CONCLUSIONS: The incidence of adverse events in home-treated PE patients, selected by a validated triage tool, was very low. Patients with cancer had a three- to five-fold higher incidence of adverse events and death. Patients with increased troponin or (NT-pro)BNP had a three-fold higher risk of adverse events, driven by recurrent venous thromboembolism and bleeding.

Right ventricle assessment in patients with pulmonary embolism at low risk for death based on clinical models: an individual patient data meta-analysis.

AIMS: Patients with acute pulmonary embolism (PE) at low risk for short-term death are candidates for home treatment or short-hospital stay. We aimed at determining whether the assessment of right ventricle dysfunction (RVD) or elevated troponin improves identification of low-risk patients over clinical models alone. METHODS AND RESULTS: Individual patient data meta-analysis of studies assessing the relationship between RVD or elevated troponin and short-term mortality in patients with acute PE at low risk for death based on clinical models (Pulmonary Embolism Severity Index, simplified Pulmonary Embolism Severity Index or Hestia). The primary study outcome was short-term death defined as death occurring in hospital or within 30 days. Individual data of 5010 low-risk patients from 18 studies were pooled. Short-term mortality was 0.7% [95% confidence interval (CI) 0.4-1.3]. RVD at echocardiography, computed tomography or B-type natriuretic peptide (BNP)/N-terminal pro BNP (NT-proBNP) was associated with increased risk for short-term death (1.5 vs. 0.3%; OR 4.81, 95% CI 1.98-11.68), death within 3 months (1.6 vs. 0.4%; OR 4.03, 95% CI 2.01-8.08), and PE-related death (1.1 vs. 0.04%; OR 22.9, 95% CI 2.89-181). Elevated troponin was associated with short-term death (OR 2.78, 95% CI 1.06-7.26) and death within 3 months (OR 3.68, 95% CI 1.75-7.74). CONCLUSION: RVD assessed by echocardiography, computed tomography, or elevated BNP/NT-proBNP levels and increased troponin are associated with short-term death in patients with acute PE at low risk based on clinical models. RVD assessment, mainly by BNP/NT-proBNP or echocardiography, should be considered to improve identification of low-risk patients that may be candidates for outpatient management or short hospital stay.

Evolution of CT findings after anticoagulant treatment for acute pulmonary embolism in patients with and without an ultimate diagnosis of chronic thromboembolic pulmonary hypertension.

INTRODUCTION: The pulmonary arterial morphology of patients with pulmonary embolism (PE) is diverse and it is unclear how the different vascular lesions evolve after initiation of anticoagulant treatment. A better understanding of the evolution of computed tomography pulmonary angiography (CTPA) findings after the start of anticoagulant treatment may help to better identify those PE patients prone to develop chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to assess the evolution of various thromboembolic lesions on CTPA over time after the initiation of adequate anticoagulant treatment in individual acute PE patients with and without an ultimate diagnosis of CTEPH. METHODS: We analysed CTPA at diagnosis of acute PE (baseline) and at follow-up in 41 patients with CTEPH and 124 patients without an ultimate diagnosis of CTEPH, all receiving anticoagulant treatment. Central and segmental pulmonary arteries were scored by expert chest radiologists as normal or affected. Lesions were further subclassified as 1) central thrombus, 2) total thrombotic occlusion, 3) mural thrombus, 4) web or 5) tapered pulmonary artery. RESULTS: Central thrombi resolved after anticoagulant treatment, while mural thrombi and total thrombotic occlusions either resolved or evolved into webs or tapered pulmonary arteries. Only patients with an ultimate diagnosis of CTEPH exhibited webs and tapered pulmonary arteries on the baseline scan. Moreover, such lesions always persisted after follow-up. CONCLUSIONS: Webs and tapered pulmonary arteries at the time of PE diagnosis strongly indicate a state of chronic PE and should raise awareness for possible CTEPH, particularly in patients with persistent dyspnoea after anticoagulant treatment for acute PE.

Lower prevalence of subsegmental pulmonary embolism after application of the YEARS diagnostic algorithm.

The rate of identified isolated subsegmental pulmonary embolism (ssPE) has doubled with advances in computed tomography pulmonary angiography (CTPA) technology, but its clinical relevance is debated. The YEARS diagnostic algorithm was shown to safely reduce the number of required CTPAs in the diagnostic management of PE. We hypothesized that the higher threshold for performing CTPA in YEARS was associated with a lower prevalence of ssPE compared to the conventional diagnostic algorithm. We compared 2291 consecutive patients with suspected PE managed according to YEARS to 3306 consecutive control patients managed according to the Wells score for the prevalence of isolated ssPE. In the YEARS cohort, 52% were managed without CTPA, 12% had pulmonary embolism (PE) of which 10% were isolated ssPE, and the 3-month diagnostic failure rate was 0·35%. In the control cohort, 32% were managed without CTPA, 20% had PE of which 16% were isolated ssPE, and the 3-month failure rate was 0·73%. The isolated ssPE prevalence was significantly lower in YEARS (absolute difference 6·2% (95% confidence interval [CI] 1·4-10), Odds Ratio 0·58 (95% CI 0·37-0·90). In conclusion, YEARS is associated with a lower prevalence of isolated ssPE, due to reduction in CTPAs by the higher D-dimer threshold. This was however not associated with a higher risk of recurrent VTE during follow-up.

Efficacy and Safety of Outpatient Treatment Based on the Hestia Clinical Decision Rule with or without N-Terminal Pro-Brain Natriuretic Peptide Testing in Patients with Acute Pulmonary Embolism. A Randomized Clinical Trial.

RATIONALE: Outpatient treatment of pulmonary embolism (PE) may lead to improved patient satisfaction and reduced healthcare costs. However, trials to assess its safety and the optimal method for patient selection are scarce. OBJECTIVES: To validate the utility and safety of selecting patients with PE for outpatient treatment by the Hestia criteria and to compare the safety of the Hestia criteria alone with the Hestia criteria combined with N-terminal pro-brain natriuretic peptide (NT-proBNP) testing. METHODS: We performed a randomized noninferiority trial in 17 Dutch hospitals. We randomized patients with PE without any of the Hestia criteria to direct discharge or additional NT-proBNP testing. We discharged the latter patients as well if NT-proBNP did not exceed 500 ng/L or admitted them if NT-proBNP was greater than 500 ng/L. The primary endpoint was 30-day adverse outcome defined as PE- or bleeding-related mortality, cardiopulmonary resuscitation, or intensive care unit admission. The noninferiority margin for the primary endpoint was 3.4%. MEASUREMENTS AND MAIN RESULTS: We randomized 550 patients. In the NT-proBNP group, 34 of 275 (12%) had elevated NT-proBNP values and were managed as inpatients. No patient (0 of 34) with an elevated NT-proBNP level treated in hospital (0%; 95% confidence interval [CI], 0-10.2%), versus no patient (0 of 23) with a post hoc-determined elevated NT-proBNP level from the direct discharge group (0%; 95% CI, 0-14.8%), experienced the primary endpoint. In both trial cohorts, the primary endpoint occurred in none of the 275 patients (0%; 95% CI, 0-1.3%) subjected to NT-proBNP testing, versus in 3 of 275 patients (1.1%; 95% CI, 0.2-3.2%) in the direct discharge group (P = 0.25). During the 3-month follow-up, recurrent venous thromboembolism occurred in two patients (0.73%; 95% CI, 0.1-2.6%) in the NT-proBNP group versus three patients (1.1%; 95% CI, 0.2-3.2%) in the direct discharge group (P = 0.65). CONCLUSIONS: Outpatient treatment of patients with PE selected on the basis of the Hestia criteria alone was associated with a low risk of adverse events. Given the low number of patients with elevated NT-proBNP levels, this trial was unable to draw definite conclusions regarding the incremental value of NT-proBNP testing in patients who fulfill the Hestia criteria. Clinical trial registered with www.trialregister.nl/trialreg/admin/rctview.asp?TC=2603 (NTR2603).

Wells Rule and d-Dimer Testing to Rule Out Pulmonary Embolism: A Systematic Review and Individual-Patient Data Meta-analysis.

BACKGROUND: The performance of different diagnostic strategies for pulmonary embolism (PE) in patient subgroups is unclear. PURPOSE: To evaluate and compare the efficiency and safety of the Wells rule with fixed or age-adjusted d-dimer testing overall and in inpatients and persons with cancer, chronic obstructive pulmonary disease, previous venous thromboembolism, delayed presentation, and age 75 years or older. DATA SOURCES: MEDLINE and EMBASE from 1 January 1988 to 13 February 2016. STUDY SELECTION: 6 prospective studies in which the diagnostic management of PE was guided by the dichotomized Wells rule and quantitative d-dimer testing. DATA EXTRACTION: Individual data of 7268 patients; risk of bias assessed by 2 investigators with the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) tool. DATA SYNTHESIS: The proportion of patients in whom imaging could be withheld based on a "PE-unlikely" Wells score and a negative d-dimer test result (efficiency) was estimated using fixed (≤500 µg/L) and age-adjusted (age × 10 µg/L in patients aged >50 years) d-dimer thresholds; their 3-month incidence of symptomatic venous thromboembolism (failure rate) was also estimated. Overall, efficiency increased from 28% to 33% when the age-adjusted (instead of the fixed) d-dimer threshold was applied. This increase was more prominent in elderly patients (12%) but less so in inpatients (2.6%). The failure rate of age-adjusted d-dimer testing was less than 3% in all examined subgroups. LIMITATION: Post hoc analysis, between-study differences in patient characteristics, use of various d-dimer assays, and limited statistical power to assess failure rate. CONCLUSION: Age-adjusted d-dimer testing is associated with a 5% absolute increase in the proportion of patients with suspected PE in whom imaging can be safely withheld compared with fixed d-dimer testing. This strategy seems safe across different high-risk subgroups, but its efficiency varies. PRIMARY FUNDING SOURCE: None.

Computerised clinical decision support for suspected PE.

This study aimed to determine the effect of an evidence-based clinical decision support (CDS) algorithm on the use and yield of CT pulmonary angiography (CTPA) and on outcomes of patients evaluated in the emergency department (ED) for suspected PE. The study included 1363 consecutive patients evaluated for suspected PE in an ED during 12 months before and 12 months after initiation of CDS use. Introduction of CDS was associated with decreased CTPA use (55% vs 49%; absolute difference (AD), 6.3%; 95% CI 1.0% to 11.6%; p=0.02). The use of CDS was associated with fewer symptomatic venous thromboembolic events during follow-up in patients with an initial negative diagnostic evaluation for PE (0.7% vs 3.2%; AD 2.5%; 95% CI 0.9% to 4.6%; p<0.01).

Risk profile and clinical outcome of symptomatic subsegmental acute pulmonary embolism.

The clinical significance of subsegmental pulmonary embolism (SSPE) remains to be determined. This study aimed to investigate whether SSPE forms a distinct subset of thromboembolic disease compared with more proximally located pulmonary embolism (PE). We analyzed 3728 consecutive patients with clinically suspected PE. SSPE patients were contrasted to patients with more proximal PE and to patients in whom suspected PE was ruled out, in regards of the prevalence of thromboembolic risk factors and the 3-month risks of recurrent venous thromboembolism (VTE) and mortality. PE was confirmed in 748 patients, of whom 116 (16%) had SSPE; PE was ruled out in 2980 patients. No differences were seen in the prevalence of VTE risk factors, the 3-month risk of recurrent VTE (3.6% vs 2.5%; P = .42), and mortality (10.7% vs 6.5%; P = .17) between patients with SSPE and those with more proximal PE. When compared with patients without PE, aged >60 years, recent surgery, estrogen use, and male gender were found to be independent predictors for SSPE, and patients with SSPE were at an increased risk of VTE during follow-up (hazard ratio: 3.8; 95% CI: 1.3-11.1). This study indicates that patients with SSPE mimic those with more proximally located PE in regards to their risk profile and clinical outcome.

Recurrence risk after anticoagulant treatment of limited duration for late, second venous thromboembolism.

Patients with a second venous thromboembolism generally receive anticoagulant treatment indefinitely, although it is known that the recurrence risk diminishes over time while the risk of hemorrhage persists with continued anticoagulation and increases with age. Based on these arguments and limited evidence for indefinitely prolonged treatment, the Dutch guidelines recommend considering treatment of a limited duration (i.e. 12 months) for a 'late' second venous thromboembolism, defined by a second venous thromboembolism diagnosed more than 1 year after discontinuing treatment for a first event. It is hypothesized that the risk of continued anticoagulation might outweigh the benefits in such circumstances. We evaluated this management in daily practice. Since 2003, limited duration of treatment was systematically considered at our hospital in consecutive patients, in whom we determined the recurrence risk. Of 131 patients with late second venous thromboembolism, 77 were treated for a limited duration, of whom 26 developed a symptomatic third venous thromboembolism thereafter during a cumulative follow-up of 277 years, resulting in an incidence rate of 9.4/100 patient-years (95% confidence interval: 6.1-14). The incidence rates in patients with unprovoked and provoked venous thromboembolism were 12/100 patient-years (95% confidence interval: 7.4-19) and 5.6/100 patient-years (95% confidence interval: 2.2-12), respectively [adjusted hazard ratio 2.8 (95% confidence interval: 1.1-7.2)]. The recurrence risk after treatment of limited duration for 'late' second venous thromboembolism exceeded the risk of hemorrhage associated with extended anticoagulation. Most patients may, therefore, be better served by treatment of indefinite duration, although the risk-benefit ratio of extended anticoagulation should be weighed for every patient.

Association between micro particle-tissue factor activity, factor VIII activity and recurrent VTE in patients with acute pulmonary embolism.

Studies on the association between microparticle expressing tissue factor (MP-TF) activity, FVIII activity ( FVIII: C) and recurrent VTE yielded inconclusive results. We studied these associations in patients diagnosed with acute pulmonary embolism. Plasma levels of MP-TF and FVIII activity were measured in 277 patients with a first and 72 patients with a recurrent VTE. All patients were categorized based on the quintiles of MP-TF and FVIII activity in those with a single VTE. For both markers, odds ratios (ORs) for recurrent VTE were computed using patients in the lowest quintile as a reference group. No association was observed between MP-TF activity and recurrent VTE, with an OR of 1.4 (95 % CI 0.7-2.9) in the highest quintile of MP-TF activity. Compared with the reference group, patients in the highest quintile of FVIII: C were at increased risk of recurrent VTE, OR 4.2 (95 % CI 1.4-12.2). MP-TF activity was not associated with recurrent VTE whereas high FVIII: C levels were associated with a 4-fold increased risk of VTE recurrence. Future prospective studies are necessary to explore the potential of FVIII: C as a tool for risk stratification, either by itself or in combination with other pro-thrombotic markers.

Optimization of the diagnostic management of clinically suspected pulmonary embolism in hospitalized patients.

Identical diagnostic algorithms for suspected pulmonary embolism (PE) are used for hospitalized patients and outpatients, while D-dimer levels, risk factors and pre-test probability for PE differ, and the percentage of patients managed without computerized tomography pulmonary angiography (CTPA) is lower in hospitalized patients. We aimed to improve the efficiency of the diagnostic algorithm by increasing the threshold of the D-dimer, the threshold of the Wells rule and by adjustments of the Wells rule. Six-hundred and twenty-four hospitalized patients from two previously performed management studies with a PE prevalence of 26% were studied. Adjustments were considered to be safe when the failure rate remained <2%. By applying standard management, 8% (49/624) were managed without CTPA with a failure rate of 0·0% (0/49; 95% confidence interval [CI] 0·0-7·3), and it was 1·7% (8/465; 95%CI 0·8-3·4) for all patients in whom PE was excluded at baseline. All evaluated adjustments resulted in an increase of the failure rate with very small improvements of the efficiency. Given these potentially small improvements and the increasing complexity of clinical practice if adjusted diagnostic algorithms for specific patient categories were introduced, we do not recommend further evaluation of any of the adjustments; we recommend that the standard diagnostic algorithm should continue to be applied.

Impact of delay in clinical presentation on the diagnostic management and prognosis of patients with suspected pulmonary embolism.

RATIONALE: The nonspecific clinical presentation of pulmonary embolism (PE) frequently leads to delay in its diagnosis. OBJECTIVES: This study aimed to assess the impact of delay in presentation on the diagnostic management and clinical outcome of patients with suspected PE. METHODS: In 4,044 consecutive patients with suspected PE, patients presenting more than 7 days from the onset of symptoms were contrasted with those presenting within 7 days as regards the safety of excluding PE on the basis of a clinical decision rule combined with D-dimer testing. Patients were followed for 3 months to assess the rates of recurrent venous thromboembolism and mortality. MEASUREMENTS AND MAIN RESULTS: A delayed presentation (presentation >7 d) was present in 754 (18.6%) of the patients. The failure rate of an unlikely clinical probability and normal D-dimer test was 0.5% (95% confidence interval [CI], 0.01-2.7) for patients with and 0.5% (95% CI, 0.2-1.2) for those without diagnostic delay. D-dimer testing yielded a sensitivity of 99% (95% CI, 96-99%) and 98% (95% CI, 97-99%) in these groups, respectively. Patients with PE with diagnostic delay more frequently had centrally located PE (41% vs. 26%; P < 0.001). The cumulative rates of recurrent venous thromboembolism (4.6% vs. 2.7%; P = 0.14) and mortality (7.6% vs. 6.6%; P = 0.31) were not different for patients with and without delayed presentation. CONCLUSIONS: PE can be safely excluded based on a clinical decision rule and D-dimer testing in patients with a delayed clinical presentation. A delayed presentation for patients who survived acute PE was associated with a more central PE location, although this did not affect the clinical outcome at 3 months.

Age-adjusted D-dimer cutoff levels to rule out pulmonary embolism: the ADJUST-PE study.

IMPORTANCE: D-dimer measurement is an important step in the diagnostic strategy of clinically suspected acute pulmonary embolism (PE), but its clinical usefulness is limited in elderly patients. OBJECTIVE: To prospectively validate whether an age-adjusted D-dimer cutoff, defined as age × 10 in patients 50 years or older, is associated with an increased diagnostic yield of D-dimer in elderly patients with suspected PE. DESIGN, SETTINGS, AND PATIENTS: A multicenter, multinational, prospective management outcome study in 19 centers in Belgium, France, the Netherlands, and Switzerland between January 1, 2010, and February 28, 2013. INTERVENTIONS: All consecutive outpatients who presented to the emergency department with clinically suspected PE were assessed by a sequential diagnostic strategy based on the clinical probability assessed using either the simplified, revised Geneva score or the 2-level Wells score for PE; highly sensitive D-dimer measurement; and computed tomography pulmonary angiography (CTPA). Patients with a D-dimer value between the conventional cutoff of 500 µg/L and their age-adjusted cutoff did not undergo CTPA and were left untreated and formally followed-up for a 3-month period. MAIN OUTCOMES AND MEASURES: The primary outcome was the failure rate of the diagnostic strategy, defined as adjudicated thromboembolic events during the 3-month follow-up period among patients not treated with anticoagulants on the basis of a negative age-adjusted D-dimer cutoff result. RESULTS: Of the 3346 patients with suspected PE included, the prevalence of PE was 19%. Among the 2898 patients with a nonhigh or an unlikely clinical probability, 817 patients (28.2%) had a D-dimer level lower than 500 µg/L (95% CI, 26.6%-29.9%) and 337 patients (11.6%) had a D-dimer between 500 µg/L and their age-adjusted cutoff (95% CI, 10.5%-12.9%). The 3-month failure rate in patients with a D-dimer level higher than 500 µg/L but below the age-adjusted cutoff was 1 of 331 patients (0.3% [95% CI, 0.1%-1.7%]). Among the 766 patients 75 years or older, of whom 673 had a nonhigh clinical probability, using the age-adjusted cutoff instead of the 500 µg/L cutoff increased the proportion of patients in whom PE could be excluded on the basis of D-dimer from 43 of 673 patients (6.4% [95% CI, 4.8%-8.5%) to 200 of 673 patients (29.7% [95% CI, 26.4%-33.3%), without any additional false-negative findings. CONCLUSIONS AND RELEVANCE: Compared with a fixed D-dimer cutoff of 500 µg/L, the combination of pretest clinical probability assessment with age-adjusted D-dimer cutoff was associated with a larger number of patients in whom PE could be considered ruled out with a low likelihood of subsequent clinical venous thromboembolism. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01134068.

Quantitative protein mass spectrometry for multiplex measurement of coagulation and fibrinolytic proteins towards clinical application: What, why and how?

Plasma proteins involved in coagulation and fibrinolysis are essential to hemostasis. Consequently, their circulating levels and functionality are critical in bleeding and thrombosis development. Well-established laboratory tests to assess these are available; however, said tests do not allow high multiplicity, require large volumes of plasma and are often costly. A novel technology to quantify plasma proteins is quantitative protein mass spectrometry (QPMS). Aided by stable isotope-labeled internal standards a large number of proteins can be quantified in one single analytical run requiring <30 µL of plasma. This provides an opportunity to improve insight in the etiology and prognosis of bleeding and thrombotic disorders, in which the balance between different proteins plays a crucial role. This manuscript aims to give an overview of the QPMS potential applications in thrombosis and hemostasis research (quantifying the 38 proteins assigned to coagulation and fibrinolysis by the KEGG database), but also to explore the potential and hurdles if designed for clinical practice. Advantages and limitations of QPMS are described and strategies for improved analysis are proposed, using as an example the test requirements for antithrombin. Application of this technology in the future could represent a step towards individualized patient care.

Use of Magnetic Resonance Direct Thrombus Imaging for the Diagnostic Management of Suspected Thrombosis in Routine Clinical Practice.

Background The noninvasive magnetic resonance direct thrombus imaging (MRDTI) technique can be used to diagnose acute deep vein thrombosis (DVT), without the use of intravenous contrast. MRDTI holds the potential to differentiate between acute and chronic DVT and could be helpful when diagnosing thrombosis is challenging. Objectives Our objective was to evaluate the application of MRDTI in clinical practice, including the frequency and indications of MRDTI scans performed in practice-based conditions, results, impact on treatment decisions, and associated patient outcomes. Methods A retrospective study was performed at the Leiden University Medical Center, the Netherlands. MRDTI scans performed since its implementation in patients aged ≥18 years as part of clinical practice for the diagnostic management of suspected thrombosis were evaluated. Results Between October 2015 and September 2023, 36 patients had undergone MRDTI for the diagnostic evaluation of thrombosis. MRDTI application increased since 2019 (five-eight scans per year). The most common indication was to differentiate between acute and chronic thrombosis, mainly for suspected recurrent ipsilateral DVT after inconclusive compression ultrasonography. In over a third of patients, acute thrombosis was confirmed by MRDTI. MRDTI results determined treatment decisions in all except two patients. One patient had symptomatic thrombosis of the lower extremity within 3 months after an MRDTI of the upper extremity without signs of acute thrombosis (1/23; 4.3%, 95% confidence interval: 0.77-21). Conclusion Over the past 4 years, MRDTI has been used increasingly in our hospital. MRDTI results guided treatment decisions, which confirms the clinical impact and feasibility of its application in daily practice.

Targeted exome analysis in patients with rare bleeding disorders: data from the Rare Bleeding Disorders in the Netherlands study.

Background: Rare coagulation factor deficiencies and disorders of fibrinolysis (defined as rare bleeding disorders [RBDs]) present with a heterogeneous bleeding phenotype, and bleeding severity is difficult to predict. Objectives: Describe underlying rare genetic variants in the Dutch RBD population and investigate the relationship between genotype, laboratory phenotype, and clinical phenotype. Methods: The Rare Bleeding Disorders in the Netherlands is a cross-sectional, nationwide study conducted between October 1, 2017, and November 30, 2019. Bleeding scores and blood samples were collected during a single study visit. Coagulation factor levels were measured centrally, and targeted exome analysis was performed on 156 genes involved in thrombosis and hemostasis. Pathogenicity was assigned according to the Association for Clinical Genetic Science guidelines. Results: Rare genetic variants specific to the diagnosed RBD were found in 132 of 156 patients (85%). Of the 214 rare genetic variants identified, 57% (n = 123) were clearly pathogenic, 19% (n = 40) were likely pathogenic, and 24% (n = 51) were variants of unknown significance. No explanatory genetic variants were found in patients with plasminogen activator inhibitor type 1 deficiency or hyperfibrinolysis. A correlation existed between factor activity levels and the presence of a genetic variant in the corresponding gene in patients with rare coagulation factor deficiencies and alpha-2-antiplasmin deficiency. Co-occurrence of multiple genetic variants was present in a quarter of patients, but effect on phenotype remains unclear. Conclusion: Targeted exome analysis may offer advantages over single-gene analysis, emphasized by a number of combined deficiencies in this study. Further studies are required to determine the role of co-occurring hemostasis gene variants on the bleeding phenotype in RBDs.

[Anti-Xa activity in LMWH treatment: when to assess and what to do with the result]. / Anti-Xa-activiteit bij laagmoleculairgewicht heparine.

The anti-factor Xa assay is designed to measure plasma low-molecular-weight heparin (LMWH) levels and to monitor heparin therapy. Notably, the results of anti-factor Xa testing cannot be used in the same way as the International Normalized Ratio (INR) is used to guide cumarin treatment: dose adjustments to remain in the therapeutic range have not been shown to be associated with better outcomes of care and lower rates of thrombotic and/or bleeding complications. The anti-factor Xa activity should therefore only be assessed in cases of considerable concern regarding an LWMH under- or overdosis. It is reasonable to lower the LMWH dose in case of a supratherapeutic anti-factor Xa activity. Increasing the LMWH dose in case of a subtherapeutic anti-factor Xa activity should however only be considered in case of morbid obesity or in the setting of breakthrough thrombosis in patients receiving therapeutic dosed LMWH, as long as the anti-factor Xa activity remains below the upper-level of the recommend range.

High prevalence of heavy menstrual bleeding in women with rare bleeding disorders in the Netherlands: retrospective data from the RBiN study.

BACKGROUND: Heavy menstrual bleeding (HMB) is associated with a reduced quality of life and limitations in social and physical functioning. Data on HMB in women with rare bleeding disorders (RBDs), including coagulation factor deficiencies and fibrinolytic disorders, are scarce. OBJECTIVES: To analyze the prevalence, severity, and treatment of HMB in Dutch women with an RBD. METHODS: The Rare Bleeding Disorders in the Netherlands (RBiN) study included 263 patients with an RBD from all 6 hemophilia treatment centers (October 2017-November 2019). In this analysis, data of 111 women aged ≥16 years were studied. According to the International Society on Thrombosis and Haemostasis bleeding assessment tool, HMB symptoms were scored from 0 (no/trivial) to 4 (severe symptoms requiring medical intervention). HMB was defined as a score ≥1. Age at RBD diagnosis was extracted from patient files. RESULTS: HMB was reported by 80% of women (89/111) and was more prevalent in women with a fibrinolytic disorder (33/35; 94%) than in women with a coagulation factor deficiency (56/76; 74%) (P = .011). Of the 89 women with HMB, 82% (n = 73) ever required treatment. Multiple treatment modalities were frequently used, both in severe and mild deficiencies. Hormonal treatment was mostly used (n = 64; 88%), while antifibrinolytics were prescribed less frequently (n = 18; 25%). In women with HMB since menarche (n = 61; 69%), median age at RBD diagnosis was 28 years (IQR, 14-41). CONCLUSION: HMB is common in women with RBDs. Women with mild deficiencies also frequently reported HMB. Only a minority of women were treated with hemostatic agents. A significant diagnostic delay was observed after the onset of HMB symptoms.