Thrombopoietin Receptor Agonists and Other Second-Line Therapies for Immune Thrombocytopenia: A Narrative Review With a Focus on Drug Access in Canada.

INTRODUCTION: Immune thrombocytopenia (ITP) is an autoimmune disease characterized by low platelet counts and increased risk of bleeding. After corticosteroids with or without intravenous immune globulin (first-line treatment), second-line treatment options include rituximab, splenectomy, thrombopoietin receptor agonists (TPO-RAs), and fostamatinib. In Canada, the choice of second-line therapy is influenced by access to medications. The goals of this narrative review are to 1) summarize the evidence for the use of TPO-RAs and other second-line therapies in ITP and 2) highlight differences in public funding criteria for TPO-RAs across provinces and territories in Canada. METHODS: We conducted a literature review of second-line therapies for ITP. We solicited information on public funding programs for TPO-RAs in Canada from health care providers, pharmacists, and provincial ministries of health. RESULTS: Head-to-head trials involving TPO-RAs, rituximab, splenectomy, and fostamatinib are lacking. There is substantial evidence of effect for TPO-RAs in improving platelet count levels, health-related quality of life, bleeding, and fatigue from placebo-controlled trials and observational studies; however, access to TPO-RAs through provincial funding programs in Canada is variable. Splenectomy failure is a prerequisite for the funding of TPO-RAs in Ontario, Manitoba, and Saskatchewan, but not in Alberta or Quebec. Other provinces either do not have access to public funding or funding is provided on a case-by-case basis. DISCUSSION: TPO-RAs are effective second-line therapies for the treatment of ITP; however, access is variable across Canada, which results in health disparities and poor uptake of international treatment guidelines.

In acutely ill inpatients, benefits and harms of anticoagulants for VTE prophylaxis were assessed.

SOURCE CITATION: Eck RJ, Elling T, Sutton AJ, et al. Anticoagulants for thrombosis prophylaxis in acutely ill patients admitted to hospital: systematic review and network meta-analysis. BMJ. 2022;378:e070022. 35788047.

Risk for Recurrent Venous Thromboembolism in Patients With Subsegmental Pulmonary Embolism Managed Without Anticoagulation : A Multicenter Prospective Cohort Study.

BACKGROUND: The incidence of pulmonary embolism has been increasing, but its case-fatality rate is decreasing, suggesting a lesser severity of illness. The clinical importance of patients with pulmonary embolism isolated to the subsegmental vessels is unknown. OBJECTIVE: To determine the rate of recurrent venous thromboembolism in patients with subsegmental pulmonary embolism managed without anticoagulation. DESIGN: Multicenter prospective cohort study. (ClinicalTrials.gov: NCT01455818). SETTING: Eighteen sites between February 2011 and February 2021. PATIENTS: Patients with isolated subsegmental pulmonary embolism. INTERVENTION: At diagnosis, patients underwent bilateral lower-extremity venous ultrasonography, which was repeated 1 week later if results were negative. Patients without deep venous thrombosis did not receive anticoagulant therapy. MEASUREMENTS: The primary outcome was recurrent venous thromboembolism during the 90-day follow-up period. RESULTS: Recruitment was stopped prematurely because the predefined stopping rule was met after 292 of a projected 300 patients were enrolled. Of the 266 patients included in the primary analysis, the primary outcome occurred in 8 patients, for a cumulative incidence of 3.1% (95% CI, 1.6% to 6.1%) over the 90-day follow-up. The incidence of recurrent venous thromboembolism was 2.1% (CI, 0.8% to 5.5%) and 5.7% (CI, 2.2% to 14.4%) over the 90-day follow-up in patients with single and multiple isolated subsegmental pulmonary embolism, respectively. No patients had a fatal recurrent pulmonary embolism. LIMITATION: The study was restricted to patients with low-risk subsegmental pulmonary embolism. CONCLUSION: Overall, patients with subsegmental pulmonary embolism who did not have proximal deep venous thrombosis had a higher-than-expected rate of recurrent venous thromboembolism. PRIMARY FUNDING SOURCE: Heart and Stroke Foundation of Canada and French Ministry of Health Programme Hospitalier de Recherche Clinique.

Apixaban to Prevent Venous Thromboembolism in Patients with Cancer.

BACKGROUND: Patients with active cancer have an increased risk of venous thromboembolism, which results in substantial morbidity, mortality, and health care expenditures. The Khorana score (range, 0 to 6, with higher scores indicating a higher risk of venous thromboembolism) has been validated to identify patients with cancer at elevated risk for this complication and may help select those who could benefit from thromboprophylaxis. METHODS: We conducted a randomized, placebo-controlled, double-blind clinical trial assessing the efficacy and safety of apixaban (2.5 mg twice daily) for thromboprophylaxis in ambulatory patients with cancer who were at intermediate-to-high risk for venous thromboembolism (Khorana score, ≥2) and were initiating chemotherapy. The primary efficacy outcome was objectively documented venous thromboembolism over a follow-up period of 180 days. The main safety outcome was a major bleeding episode. RESULTS: Of the 574 patients who underwent randomization, 563 were included in the modified intention-to-treat analysis. Venous thromboembolism occurred in 12 of 288 patients (4.2%) in the apixaban group and in 28 of 275 patients (10.2%) in the placebo group (hazard ratio, 0.41; 95% confidence interval [CI], 0.26 to 0.65; P<0.001). In the modified intention-to-treat analysis, major bleeding occurred in 10 patients (3.5%) in the apixaban group and in 5 patients (1.8%) in the placebo group (hazard ratio, 2.00; 95% CI, 1.01 to 3.95; P = 0.046). During the treatment period, major bleeding occurred in 6 patients (2.1%) in the apixaban group and in 3 patients (1.1%) in the placebo group (hazard ratio, 1.89; 95% CI, 0.39 to 9.24). CONCLUSIONS: Apixaban therapy resulted in a significantly lower rate of venous thromboembolism than did placebo among intermediate-to-high-risk ambulatory patients with cancer who were starting chemotherapy. The rate of major bleeding episodes was higher with apixaban than with placebo. (Funded by the Canadian Institutes of Health Research and Bristol-Myers Squibb-Pfizer Alliance; AVERT ClinicalTrials.gov number, NCT02048865.).

Screening for Occult Cancer in Unprovoked Venous Thromboembolism.

BACKGROUND: Venous thromboembolism may be the earliest sign of cancer. Currently, there is a great diversity in practices regarding screening for occult cancer in a person who has an unprovoked venous thromboembolism. We sought to assess the efficacy of a screening strategy for occult cancer that included comprehensive computed tomography (CT) of the abdomen and pelvis in patients who had a first unprovoked venous thromboembolism. METHODS: We conducted a multicenter, open-label, randomized, controlled trial in Canada. Patients were randomly assigned to undergo limited occult-cancer screening (basic blood testing, chest radiography, and screening for breast, cervical, and prostate cancer) or limited occult-cancer screening in combination with CT. The primary outcome measure was confirmed cancer that was missed by the screening strategy and detected by the end of the 1-year follow-up period. RESULTS: Of the 854 patients who underwent randomization, 33 (3.9%) had a new diagnosis of occult cancer between randomization and the 1-year follow-up: 14 of the 431 patients (3.2%) in the limited-screening group and 19 of the 423 patients (4.5%) in the limited-screening-plus-CT group (P=0.28). In the primary outcome analysis, 4 occult cancers (29%) were missed by the limited screening strategy, whereas 5 (26%) were missed by the strategy of limited screening plus CT (P=1.0). There was no significant difference between the two study groups in the mean time to a cancer diagnosis (4.2 months in the limited-screening group and 4.0 months in the limited-screening-plus-CT group, P=0.88) or in cancer-related mortality (1.4% and 0.9%, P=0.75). CONCLUSIONS: The prevalence of occult cancer was low among patients with a first unprovoked venous thromboembolism. Routine screening with CT of the abdomen and pelvis did not provide a clinically significant benefit. (Funded by the Heart and Stroke Foundation of Canada; SOME ClinicalTrials.gov number, NCT00773448.).

Risk factors predictive of occult cancer detection in patients with unprovoked venous thromboembolism.

Risk factors predictive of occult cancer detection in patients with a first unprovoked symptomatic venous thromboembolism (VTE) are unknown. Cox proportional hazard models and multivariate analyses were performed to assess the effect of specific risk factors on occult cancer detection within 1 year of a diagnosis of unprovoked VTE in patients randomized in the Screening for Occult Malignancy in Patients with Idiopathic Venous Thromboembolism (SOME) trial. A total of 33 (3.9%; 95% CI, 2.8%-5.4%) out of the 854 included patients received a new diagnosis of cancer at 1-year follow-up. Age ≥ 60 years (hazard ratio [HR], 3.11; 95% CI, 1.41-6.89; ITALIC! P= .005), previous provoked VTE (HR, 3.20; 95% CI, 1.19-8.62; ITALIC! P= .022), and current smoker status (HR, 2.80; 95% CI, 1.24-6.33; ITALIC! P= .014) were associated with occult cancer detection. Age, prior provoked VTE, and smoking status may be important predictors of occult cancer detection in patients with first unprovoked VTE. This trial was registered atwww.clinicaltrials.govas #NCT00773448.

Perioperative Management of Dabigatran: A Prospective Cohort Study.

BACKGROUND: The perioperative management of dabigatran in clinical practice is heterogeneous. We performed this study to evaluate the safety of perioperative management of dabigatran using a specified protocol. METHODS AND RESULTS: Patients treated with dabigatran and planned for an invasive procedure were eligible for inclusion. The timing of the last dose of dabigatran before the procedure was based on the creatinine clearance and procedure-related bleeding risk. Resumption of dabigatran was prespecified according to the complexity of the surgery and consequences of a bleeding complication. Patients were followed up for 30 days for major bleeding (primary outcome), minor bleeding, arterial thromboembolism, and death. We included 541 cases: 324 procedures (60%) with standard risk of bleeding and 217 procedures (40%) with increased risk of bleeding. The last dose of dabigatran was at 24, 48, or 96 hours before surgery according to the protocol in 46%, 37%, and 6%, respectively, of the patients. Resumption was timed according to protocol in 77% with 75 mg as the first dose on the day of procedure in 40% of the patients. Ten patients (1.8%; 95% confidence interval, 0.7-3.0) had major bleeding, and 28 patients (5.2%; 95% confidence interval, 3.3-7.0) had minor bleeding events. The only thromboembolic complication was transient ischemic attack in 1 patient (0.2%; 95% confidence interval, 0-0.5), and there were 4 deaths unrelated to bleeding or thrombosis. Bridging was not used preoperatively but was administered in 9 patients (1.7%) postoperatively. CONCLUSION: Our protocol for perioperative management of dabigatran appears to be effective and feasible.

Design of the rivaroxaban for heparin-induced thrombocytopenia study.

Rivaroxaban is an ideal potential candidate for treatment of heparin-induced thrombocytopenia (HIT) because it is administered orally by fixed dosing, requires no laboratory monitoring and is effective in the treatment of venous and arterial thromboembolism in other settings. The Rivaroxaban for HIT study is a prospective, multicentre, single-arm, cohort study evaluating the incidence of new symptomatic venous and arterial thromboembolism in patients with suspected or confirmed HIT who are treated with rivaroxaban. Methodological challenges faced in the design of this study include heterogeneity of the patient population, differences in the baseline risk of thrombosis and bleeding dependent on whether HIT is confirmed or just suspected, and heterogeneity in laboratory confirmation of HIT. The rationale for how these challenges were addressed and the final design of the Rivaroxaban for HIT study is reviewed.

Implications of Dabigatran, a direct thrombin inhibitor, for oral surgery practice.

Direct thrombin inhibitors, specifically orally administered dabigatran etexilate, are emerging as alternatives to warfarin for anticoagulation in the management of atrial fibrillation and venous thromboembolism. The risk associated with bleeding events while taking dabigatran has been documented in multiple randomized controlled trials, but to date, no studies have focused on the risk of bleeding after dental extraction. Extraction of teeth is one of the most common surgical procedures and may cause significant bleeding, so a thorough understanding of the pharmacology of anticoagulant medications is required to prevent complications. With the increasing use of direct thrombin inhibitors, the safe management of patients taking these anticoagulants must be delineated. This review compares dabigatran and warfarin, especially in terms of their effects on dental and oral surgery practice, and examines best management of these patients in light of the existing literature.

Breaking down tumor thrombus: Current strategies for medical management.

Tumor thrombus, the intravascular extension of tumor into adjacent blood vessels, is frequently encountered in patients with renal cell carcinoma and hepatocellular carcinoma, and often involves the abdominal vasculature including the renal vein, portal vein, and the inferior vena cava. While a bland thrombus is composed of platelets and fibrin, in contrast, a tumor thrombus refers to an organized collection of tumor cells. Though oftentimes detected incidentally on imaging, tumor thrombus may have significant clinical implications and can be challenging to differentiate from bland thrombus. Additionally, the optimal management of tumor thrombus, including the use of anticoagulation, remains poorly described. This review summarizes common causes of tumor thrombus, as well as its impact on staging, prognosis, and treatment.

Performance and Head-to-Head Comparison of Three Clinical Models to Predict Occurrence of Postthrombotic Syndrome: A Validation Study.

OBJECTIVE: The SOX-PTS, Amin, and Méan models are three different clinical prediction scores stratifying the risk for postthrombotic syndrome (PTS) development in patients with acute deep vein thrombosis (DVT) of the lower limbs. Herein, we aimed to assess and compare these scores in the same cohort of patients. METHODS: We retrospectively applied the three scores in a cohort of 181 patients (196 limbs) who participated in the SAVER pilot trial for an acute DVT. Patients were stratified into PTS risk groups using positivity thresholds for high-risk patients as proposed in the derivation studies. All patients were assessed for PTS 6 months after index DVT using the Villalta scale. We calculated the predictive accuracy for PTS and area under receiver operating characteristic (AUROC) curve for each model. RESULTS: The Méan model was the most sensitive (sensitivity 87.7%; 95% confidence interval [CI]: 77.2-94.5) with the highest negative predictive value (87.5%; 95% CI: 76.8-94.4) for PTS. The SOX-PTS was the most specific score (specificity 97.5%; 95% CI: 92.7-99.5) with the highest positive predictive value (72.7%; 95% CI: 39.0-94.0). The SOX-PTS and Méan models performed well for PTS prediction (AUROC: 0.72; 95% CI: 0.65-0.80 and 0.74; 95% CI: 0.67-0.82), whereas the Amin model did not (AUROC: 0.58; 95% CI: 0.49-0.67). CONCLUSION: Our data support that the SOX-PTS and Méan models have good accuracy to stratify the risk for PTS.

Apixaban thromboprophylaxis in ambulatory patients with cancer and obesity: Insights from the AVERT trial.

BACKGROUND: The use of direct oral anticoagulants (DOACs) in obese patients is uncertain. It is unclear if body mass index (BMI) affects the safety and efficacy of DOACs for the primary prevention of venous thromboembolism (VTE) in high-risk ambulatory patients with cancer. We sought to determine the outcomes associated with the use of apixaban for the primary prevention of cancer-associated VTE according to BMI. METHODS: The randomized, double-blinded, placebo-controlled AVERT trial evaluated apixaban thromboprophylaxis in intermediate-to-high risk ambulatory cancer patients receiving chemotherapy. For this post-hoc analysis, the primary efficacy and safety outcomes were objectively confirmed VTE and clinically relevant bleeding (major and clinically relevant non-major bleeding), respectively. Obesity was defined as BMI ≥30 kg/m2. RESULTS: Among 574 patients randomized, 217 (37.8 %) patients had BMI ≥30 kg/m2. Obese patients were overall younger, more likely to be female, had higher creatinine clearance and hemoglobin, lower platelet count, and better ECOG performance status. Compared to placebo, apixaban thromboprophylaxis was associated with reduced VTE in both obese (hazard ratio [HR] 0.26; 95 % confidence interval [CI], 0.14-0.46; p < 0.0001) and non-obese (HR 0.54; 95%CI, 0.29-1.00; p = 0.049) patients. The HR for clinically relevant bleeding (apixaban vs. placebo) was numerically higher in obese (2.09; 95%CI, 0.96-4.51; p = 0.062) than non-obese subjects (1.23; 95%CI, 0.71-2.13; p = 0.46), but overall in line with the risks observed in the general trial population. CONCLUSIONS: In the AVERT trial enrolling ambulatory cancer patients receiving chemotherapy, we found no substantial differences in the efficacy or safety of apixaban thromboprophylaxis across obese and non-obese subjects.

Practical Considerations for the Management of Cancer-Associated Venous Thromboembolism: A Guide for the General Oncology Practitioner.

Cancer-associated venous thromboembolism is a devastating complication of cancer and is associated with significant morbidity and mortality. The cornerstone of cancer-associated venous thromboembolism treatment is anticoagulation, and in recent years, there have been notable randomized clinical trials that have revealed insights into the efficacy and safety of direct oral anticoagulants and low-molecular-weight heparin in the treatment of cancer-associated thrombosis. Deciding on the ideal anticoagulation treatment plan for a patient with a cancer-associated thrombosis is a complex task that requires an understanding of clinical trial data, society guidelines, and, most importantly, consideration of many cancer-related, treatment-related, and patient-related factors. This article summarizes important factors to consider when deciding on anticoagulation therapy for a patient with cancer-associated thrombosis.

Efficacy and safety of apixaban for primary prevention of thromboembolism in patients with cancer and a central venous catheter: A subgroup analysis of the AVERT Trial.

INTRODUCTION: Central venous catheters (CVC) are associated with an increased risk of venous thromboembolism (VTE) in patients with cancer. Primary thromboprophylaxis using a direct oral anticoagulant decreases the risk of VTE in intermediate-to-high risk ambulatory cancer patients. We assessed the efficacy and safety of thromboprophylaxis with apixaban in the subpopulation of patients with cancer and a CVC in the AVERT trial. METHODS: The AVERT study was a randomized, placebo-controlled, double-blind clinical trial assessing the efficacy and safety of apixaban for primary thromboprophylaxis in patients with cancer initiating chemotherapy who were at intermediate to high risk of VTE. The primary efficacy outcome was objectively confirmed VTE within 180 days of randomization and the primary safety outcome was major bleeding. The hazard ratios (HRs) were calculated using a Cox regression model controlling for age, gender, and center. RESULTS: A total of 217 patients had a CVC and were included in the subgroup analyses with 126 and 91 patients receiving apixaban or placebo, respectively. VTE occurred in 6 (4.8%) patients in the apixaban group and 17 (18.7%) patients in the placebo group (HR 0.26; 95% CI, 0.14-0.47; p < 0.0001). Major bleeding occurred in 2 (1.6%) patients in the apixaban group and 2 (2.2%) patients in the placebo group (HR 0.69; 95% CI, 0.20-2.35; p = 0.556). CONCLUSIONS: Primary thromboprophylaxis with apixaban in patients with cancer and a CVC was associated with a reduced risk of VTE in the AVERT study population, without an increased risk of bleeding. (Funded by the CIHR and Bristol-Myers Squibb-Pfizer Alliance; NCT02048865).

Step down to 6 months of prophylactic-dose low molecular weight heparin after initial full-dose anticoagulation for the treatment of cancer-associated thrombosis (STEP-CAT): A pilot study.

BACKGROUND: Patients with cancer-associated thrombosis (CAT) are treated with full-dose anticoagulation for at least 3 months, but optimal dosing thereafter is unknown. AIM: We explored the feasibility of extended prophylactic-dose low molecular weight heparin (LMWH) treatment following a minimum of 3 months of full-dose LMWH. METHODS: We conducted a multicenter prospective pilot study of patients with CAT who completed at least 3 months of therapeutic-dose LMWH. Patients received 6 months of prophylactic-dose subcutaneous enoxaparin (40 mg once daily). The primary outcome was recurrence of deep vein thrombosis (DVT) or pulmonary embolism (PE), and secondary outcomes included major, clinically relevant non-major (CRNM), and minor bleeding. RESULTS: From August 2016 to May 2019, 52 patients with a mean age of 64.1 years were included. The study was stopped early because of poor recruitment. Breast (23.1%) and colorectal (19.2%) were the most common cancers, and 61.0% had stage IV malignancy. Index CAT consisted of DVT alone in 57.7% of patients and pulmonary embolism (PE) with or without DVT in 42.3%. Patients received a mean of 7.6 months of weight-adjusted LMWH before enrollment. During a mean follow-up of 5.6 months, one patient was diagnosed with recurrent incidental PE (0.0035 events/subject-month). There were no major bleeding events, one CRNM, and one minor bleeding event. Eight (15.4%) patients died; six from cancer and two from respiratory disease unrelated to PE. CONCLUSIONS: These results, in part, provide support for trials of extended reduced-dose anticoagulation for the secondary prevention of CAT. (ClinicalTrials.gov: NCT02752607).

Prevention of post-thrombotic syndrome with rosuvastatin: A multicenter randomized controlled pilot trial (SAVER).

BACKGROUND: Post-thrombotic syndrome (PTS) is one of the most frequent complications of venous thromboembolism (VTE) leading to considerable morbidity and cost. Apart from appropriate anticoagulation, there is no drug or medical intervention that helps to prevent PTS. We conducted a multicenter randomized controlled trial to determine whether rosuvastatin can prevent PTS. METHODS: 312 patients receiving standard anticoagulation for a newly diagnosed VTE were randomly allocated to adjuvant rosuvastatin 20 mg once daily for 180 days (n = 155) or no rosuvastatin (n = 157). At the last study visit (Day 180 ± 21), an independent observer who was blinded to study treatment performed a PTS assessment using the Villalta scale. The primary clinical outcome of the trial was mean Villalta score at Day 180. We also explored the presence of PTS as defined by Villalta score > 4 at Day 180. Patients mean age was 46.7 ± 10.8 years, 55.8% were female. RESULTS: At Day 180, the Villalta score was 3.5 ± 0.3 in the rosuvastatin arm vs. 3.3 ± 0.3 in the control arm (p = 0.59), and presence of PTS (Villalta >4) was 29.7% in the rosuvastatin arm vs. 25.5% in the control arm (p = 0.41). Secondary analyses showed no difference between trial arms for presence of severe PTS at Day 180 (2.0% vs. 2.7%, p = 1) and for changes in Villalta score between baseline and Day 180 (-3.7 ± 4.4 vs. -4.0 ± 5.0, p = 0.59). CONCLUSION: This randomized controlled pilot trial did not demonstrate efficacy of rosuvastatin to reduce Villalta score. Further studies with longer duration of exposure to rosuvastatin are needed. TRIAL REGISTRATION: ClinicalTrials.gov, number NCT02679664.

Statins for venous event reduction in patients with venous thromboembolism: A multicenter randomized controlled pilot trial assessing feasibility.

BACKGROUND: Statins may reduce the risk for recurrent venous thromboembolism (VTE); however, no randomized trials have explored this hypothesis. We performed a pilot randomized trial to determine feasibility of recruitment for a larger trial of secondary VTE prevention with rosuvastatin. METHODS: Patients with a newly diagnosed symptomatic proximal deep vein thrombosis and/or pulmonary embolism, receiving standard anticoagulation, were randomly allocated to adjuvant rosuvastatin 20 mg once daily for 180 days or no rosuvastatin for 6 months. RESULTS: Between November 2016 and December 2019, 3391 patients were assessed for eligibility in six centers. Of these patients, 1347 (39.7%) were eligible and approached for participation in the trial and 312 (23.1%) were randomized. The mean rate of randomization was 8.2 ± 4.3 patients per month. During follow-up, five recurrent VTE events were observed, three (1.9%) in the rosuvastatin group (two pulmonary embolism, one deep vein thrombosis), and two (1.3%) in the control group (two pulmonary embolism; P = 0.68). One major arterial event occurred in the rosuvastatin arm and none in the control arm (0.6% vs. 0%, P = 0.50). CONCLUSION: This pilot trial supports the feasibility of a larger scale randomized controlled trial to determine the efficacy of adjuvant rosuvastatin for the secondary prevention of VTE.

External Validation of the Patient-Reported Villalta Scale for the Diagnosis of Postthrombotic Syndrome.

INTRODUCTION: The Villalta scale is the endorsed tool to diagnose and grade the severity of postthrombotic syndrome (PTS); however, assessing presence and severity of PTS is time-consuming and relies on both the clinician and patient's assessments. The patient-reported Villalta scale version 2 (PRV2) is a visually assisted form that enables patients to self-assess presence and severity of PTS. Herein, we report on external validation of this tool. METHODS: We assessed the agreement and kappa values of PRV2 to diagnose and assess severity of PTS compared with the original Villalta score in a cohort of 181 patients (196 limbs) who participated in the SAVER pilot randomized control trial. Presence of PTS was defined as PRV2 ≥5 or a Villalta score ≥5. RESULTS: PTS prevalence was 42% using PRV2 and 33% using the Villalta scale. The corresponding kappa and percentage agreement were 0.60 (95% confidence interval [CI]: 0.49-0.71) and 81% (95% CI: 76-87), respectively. Kappa values and percentage agreements between PRV2 and Villalta scale increased with increasing severity of PTS. The sensitivity of PRV2 to detect PTS of any severity was 84% (95% CI: 73-92) with a specificity of 79% (95% CI: 71-86). CONCLUSION: We conclude that the PRV2 is an acceptable tool for diagnosing and grading the severity of PTS.

Development and internal validation of a clinical prediction model for the diagnosis of immune thrombocytopenia.

BACKGROUND: Immune thrombocytopenia (ITP) is a diagnosis of exclusion that can resemble other thrombocytopenic disorders. OBJECTIVES: To develop a clinical prediction model (CPM) for the diagnosis of ITP to aid hematogists in investigating patients presenting with undifferentiated thrombocytopenia. METHODS: We designed a CPM for ITP diagnosis at the time of the initial hematology consultation using penalized logistic regression based on data from patients with thrombocytopenia enrolled in the McMaster ITP registry (n = 523) called the Predict-ITP Tool. The case definition for ITP was a platelet count less than 100 × 109 /L and a platelet count response after high-dose corticosteroids or intravenous immune globulin, defined as the achievement of a platelet count above 50 × 109 /L and at least a doubling of baseline. Internal validation was done using bootstrap resampling. Model discrimination was assessed by the c-statistic, and calibration was assessed by the calibration slope, calibration-in-the-large, and calibration plot. RESULTS: The final model included the following variables: (1) platelet count variability (based on three or more platelet count values), (2) lowest platelet count value, (3) maximum mean platelet volume, and (4) history of major bleeding (defined by the ITP bleeding scale). The optimism-corrected c-statistic was 0.83, the calibration slope was 0.88, and calibration-in-the-large for all performance measures was <0.001 with standard error <0.001, indicating good discrimination and excellent calibration. CONCLUSIONS: The Predict-ITP Tool can estimate the likelihood of ITP for a given patient with thrombocytopenia at the time of the initial hematology consultation. The tool had high predictive accuracy for the diagnosis of ITP.

MUFFIN-PTS trial, Micronized Purified Flavonoid Fraction for the Treatment of Post-Thrombotic Syndrome: protocol of a randomised controlled trial.

INTRODUCTION: After deep vein thrombosis, up to 50% of patients develop post-thrombotic syndrome (PTS). PTS is a chronic condition that reduces quality of life (QOL). Cornerstones of PTS treatment include the use of elastic compression stockings but this treatment is usually incompletely effective and is burdensome. Venoactive drugs have been reported to be effective to treat chronic venous insufficiency (CVI). However, the level of evidence supporting their use in CVI in general and in PTS in particular is low. METHODS AND ANALYSIS: The MUFFIN-PTS trial is an academic, publically funded, multicentre randomised placebo-controlled trial assessing the efficacy of micronised purified flavonoid fraction (MPFF, Venixxa), a venoactive drug, to treat PTS. Eighty-six patients with PTS (Villalta score (VS) ≥5) and experiencing at least two of the following PTS manifestations among daily leg heaviness, cramps, pain or oedema will be randomised to receive 1000 mg of oral MPFF or a similar appearing placebo for 6 months, in addition to their usual PTS treatment. Total study follow-up will be 9 months, with visits at inclusion/baseline, 3, 6 and 9 months. Primary outcome is the proportion of patients with improvement in VS in each group, where improvement is defined as a decrease of at least 30% in VS or a VS <5 in the PTS-affected leg. Main secondary outcomes include QOL and patient satisfaction. ETHICS AND DISSEMINATION: Primary ethics approval was received from Centre intégré universitaire de santé et de services sociaux (CIUSSS) West-Central Montreal Research Ethics Board. Results of the study will be disseminated via peer-reviewed publications and presentations at scientific conferences. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT03833024); Pre-results.