Clinical Research Directory

DEFIANCE: RCT of ClotTriever System Versus Anticoagulation In Deep Vein Thrombosis

This study is a prospective, multicenter, randomized controlled trial of an interventional strategy using the ClotTriever System to achieve and maintain vessel patency (ClotTriever Intervention Arm) versus conservative medical management using anticoagulation therapy alone (Conservative Medical Management Arm) in the treatment of subjects with symptomatic unilateral iliofemoral DVT. The study will collect data on demographics, comorbidities, details from the DVT diagnosis and treatment, and clinical outcomes through the 6-month follow up visit.

Evaluation of the SCALED (SCaling AcceptabLE cDs)

This project will adapt a currently deployed Clinical Decision Support (CDS) system to deliver a VTE prevention guideline for adult patients with traumatic brain injury (TBI). We believe this is an ideal PCOR use case given PCORI's continued effort to combat VTE in trauma and our experience previously implementing this guideline. The Our overall goal is to successfully scale, evaluate, and maintain an interoperable TBI CDS across 7 total institutions.

The Protrieve PROTECTOR Study

The Protrieve PROTECTOR Study is a prospective, single-arm, multicenter study of the Protrieve Sheath.

Impact of COVID-19 Vaccines on Cerebrovascular Health

Safe and effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines may reduce the transmission of and achieve population immunity against the COVID-19 pandemic, which accounted for more than 3.75million deaths worldwide. With World Health Organization's (WHO) effort on ensuring equitable access to COVID-19 vaccines, vaccination rate may increase in the near future. On the other hand, vaccination hesitancy has emerged as a major hindrance on the global vaccination campaigns in certain areas due to safety concerns, social factors, and public health policies. For instance, a recent survey conducted in Hong Kong showed a low vaccine acceptance rate of 37%. Long-term safety concerns and post-vaccination events relayed by the social media maybe reasons for vaccination hesitancy. Among which, cerebrovascular accidents (CVA) after vaccination were one of the most frequently reported post-vaccination events. These reports ranged from ischemic strokes in elderly patients with multiple cardiovascular co-morbidities, to hemorrhage strokes in otherwise "young-and-fit" adults. While many of these events were investigated by the COVID-19 immunization expert committee, an important premise to address the apprehension of CVA after vaccination is the provision of evidence-based information of the impact of COVID-19 vaccines on brain health. In this prospective, longitudinal, observational study, we aim to elucidate the relationship between COVID-19 vaccines and cerebrovascular health in healthy citizens in a population-based cohort.

DOAC in Chinese Patients With Atrial Fibrillation

Direct oral anticoagulants (DOACs) have emerged as safe and efficacious ischemic stroke prophylaxis for non-valvular atrial fibrillation (NVAF). All four DOACs - apixaban, dabigatran, edoxaban, and rivaroxaban - were shown to reduce the risk of major bleeding compared to warfarin. The predictable pharmacokinetic profiles of DOACs also favour their use over warfarin. Together with increasing AF incidence due to population ageing, increased AF detection, and territory-wide reimbursement schemes, DOAC prescriptions have been surging worldwide. In Hong Kong, more than 78,354 patients received DOAC from January 2009 through April 2021 according to the Hospital Authority registry. The more liberal use of DOACs has led to new issues that require a thorough understanding of ethnic-specific DOAC pharmacokinetic profiles. For instance, 12- 15% of anticoagulated patients annually required interventional procedures that involve temporary discontinuation of DOAC for 48 hours or more. Although guideline-based periprocedural DOAC interruption resulted in a low 30-day thromboembolism rate of 0.16% - 0.6% in a Caucasian cohort, same measures for elective colonoscopies in a local population-based study resulted in a 30-day periprocedural thromboembolism rate of up to 2.2%. Although these studies cannot be compared directly, the remarkable interethnic discrepancy between the two cohorts warrants further pharmacokinetic and pharmacogenomic studies. More importantly, quantifying residual DOAC levels during the interruption periods may imply on duration of periprocedural DOAC interruption, length of hospital-stay, and the risk of thromboembolic and bleeding complications. Mapping inter- and intra-individual variations in DOAC levels may also impact on the management of ischemic stroke among DOAC recipients. Epidemiological studies have shown alarmingly up to 13% of acute ischemic stroke patients were on anticoagulation prior to stroke onset with increasing number of DOAC. These patients received low rates of recanalization therapy due to apprehension of bleeding complications, thus compromised survival and neurological recovery. A prospective study that reveals Asian-specific DOAC pharmacokinetic profiles may inform cross-disciplinary, territory-wide periprocedural care and acute stroke intervention strategy for the rapidly expanding DOAC population.

The PARTUM Trial: Postpartum Aspirin to Reduce Thromboembolism Undue Morbidity

The goal of the PARTUM trial is to determine if taking low-dose aspirin daily for 6 weeks after delivery is similar (non-inferior) to usual care low-molecular-weight heparin injections to prevent venous thromboembolism (VTE: blood clots in the legs or lungs) for postpartum individuals with VTE risk factors.

Aspiration Thrombectomy Using the Symphony or Prodigy System

The study is designed to evaluate the short-term and long-term clinical performance and safety of the Symphony and Prodigy thrombectomy systems used in endovascular procedures across the peripheral or pulmonary vasculature.

Colchicine to Quench the Inflammatory Response After Deep Vein Thrombosis (The Conquer-DVT Pilot Trial)

This trial seeks to assess the feasibility of a full-scale, double-blind, placebo-controlled, randomized trial assessing whether low-dose colchicine (0.5 mg daily) reduces the risk of post-thrombotic syndrome (PTS) in patients with proximal lower extremity deep vein thrombosis (DVT).

Reducing Gastrointestinal Bleeding With Proton Pump Inhibitor Therapy in Acute Venous Thromboembolism

The investigators are studying whether treatment with a proton pump inhibitor called omeprazole reduces gastrointestinal bleeding in older adults taking blood thinners for a blood clot (venous thromboembolism). The purpose of this study, a pilot study or a feasibility study, is to test the study plan and determine whether enough participants will join a larger study and accept the study procedures.

Pulmonary Embolism in Patients With Acute Heart Failure (PEHF Study)

This study focuses on two serious and common medical conditions: heart failure and pulmonary embolism (a blood clot in the lungs). Heart failure happens when the heart cannot pump blood effectively, and it is one of the main reasons older adults are admitted to the hospital. Pulmonary embolism can be life-threatening and may worsen heart failure or even trigger it. Doctors believe that pulmonary embolism may often go undetected in patients who come to the hospital with symptoms of acute heart failure, such as sudden shortness of breath. This is because both conditions can cause similar symptoms, making it difficult to tell them apart. As a result, doctors may sometimes assume the symptoms are only due to heart failure and not investigate further for a possible blood clot. However, missing a pulmonary embolism can have serious consequences. Studies suggest that some patients with heart failure who die may actually have had an undiagnosed pulmonary embolism. Current medical guidelines recommend checking for pulmonary embolism when the cause of breathing problems is unclear, but in real-life practice, this is not always done. The goal of this study is to find out whether pulmonary embolism is underdiagnosed in patients with suspected acute heart failure and whether systematically testing for it could improve patient outcomes. To do this, the study will compare two approaches in several hospitals. In half of the hospitals, doctors will follow their usual practice and decide case by case whether to test for pulmonary embolism. In the other half, doctors will systematically test all eligible patients for pulmonary embolism using recommended diagnostic methods. Adult patients admitted with recent or worsening breathing difficulties and signs of acute heart failure may be included in the study, provided they give their consent. Researchers will collect information about their symptoms, tests, diagnosis, and treatments. Patients will be monitored during their hospital stay and for three months afterward. The study will track important outcomes such as survival, new blood clots, bleeding events, repeated hospital visits for breathing problems, and overall time spent in the hospital. The researchers expect to include about 740 patients in total. They estimate that pulmonary embolism may be found in about 1% of patients with usual care, but up to 5% when doctors systematically look for it. This study aims to better understand how often pulmonary embolism occurs in patients with acute heart failure and whether more systematic testing could lead to earlier diagnosis and better care. The results could help improve medical practice and reduce complications or deaths related to missed diagnoses.

The Effect of a VTE Prevention Care Bundle in Total Hip Arthroplasty Patients

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), remains a critical and potentially life-threatening complication following total hip arthroplasty (THA). Despite standard prophylactic measures, the incidence of VTE can be significant, highlighting the need for comprehensive and structured nursing interventions. A "care bundle" approach-a targeted set of evidence-based practices performed collectively and reliably-has been shown to improve patient outcomes and minimize complications in various clinical settings. This non-randomized controlled clinical trial aims to investigate the effect of a specifically designed VTE Prevention Care Bundle on clinical outcomes in patients recovering from total hip arthroplasty. The central hypothesis is that the systematic implementation of this care bundle will result in optimized clinical parameters, enhanced recovery experiences, and minimized VTE risks compared to standard routine care. Study Design and Population: The study utilizes a quasi-experimental, non-randomized controlled design. Participants are adult patients who have undergone total hip arthroplasty. The Autar DVT Risk Assessment Scale is utilized strictly as an objective filtering tool during the patient selection process (inclusion criteria). Participants are systematically assigned to either a control group or an intervention group based on the study protocol phases. Interventions: Control Group: Patients receive the standard, routine orthopedic nursing care provided by the hospital, alongside the standard medical prophylaxis prescribed by their attending physicians. Intervention Group: Patients receive the specialized VTE Prevention Care Bundle. This comprehensive bundle consists of five core components: Education: Providing verbal and written information to the patient during the preoperative period. Early Mobilization: Ensuring controlled ambulation and mobilization in the early postoperative period. Exercise: Instructing and monitoring in-bed ankle-pumping exercises. Fluid Management: Encouraging adequate hydration and closely monitoring fluid intake. Mechanical Prophylaxis: Ensuring the correct application and continuous monitoring of elastic compression stockings. Data Collection and Follow-up Tools: Data is collected systematically during the inpatient stay and throughout a 90-day post-discharge period using the following tools: Descriptive Data Form: Records demographic and clinical characteristics (age, BMI, surgical history). Clinical Follow-up Chart: A researcher-developed form tracking leg circumference, Homan's sign, edema, erythema, vital signs, and International Normalized Ratio (INR) levels. Comfort Scale After Hip Prosthesis: A 26-item scale used to evaluate the patient's postoperative comfort. Newcastle Satisfaction with Nursing Care Scale: A 19-item scale evaluating patient satisfaction with the nursing care received. Likert-Type Fear of Falling Scale: Assesses patients' fear levels during mobilization. Post-Discharge 90-Day Follow-up Chart: A researcher-developed form utilized to monitor any hospital admissions or readmissions due to suspected VTE symptoms (leg swelling, pain, shortness of breath) during the 3-month follow-up period. Funding Status: A grant application for this research project has been submitted to The Scientific and Technological Research Council of Türkiye (TUBITAK) and is currently under evaluation.

Replication of the EINSTEIN-DVT Anticoagulant Trial in Healthcare Claims Data

Investigators are building an empirical evidence base for real world data through large-scale replication of randomized controlled trials. The investigators' goal is to understand for what types of clinical questions real world data analyses can be conducted with confidence and how to implement such studies.

Timing of Thromboprophylaxis After Postpartum Hemorrhage

Postpartum hemorrhage is a leading cause of maternal morbidity and mortality worldwide. Women who experience severe postpartum hemorrhage are at increased risk of both recurrent bleeding and venous thromboembolism. The optimal timing for starting pharmacological thromboprophylaxis after postpartum hemorrhage remains uncertain. This retrospective observational cohort study was conducted at the Center of Maternity and Neonatology of Tunis, Tunisia. The study included women who experienced postpartum hemorrhage between 2018 and 2024 and received pharmacological thromboprophylaxis during the postpartum period. The objective was to evaluate the association between the timing of thromboprophylaxis initiation and the occurrence of thromboembolic and hemorrhagic complications. The findings are expected to contribute to the optimization of thromboprophylaxis timing after postpartum hemorrhage and to improve the balance between the prevention of venous thromboembolism and the risk of recurrent bleeding.

A Study to Observe the Pattern of Use and Safety of Rivaroxaban in Children Under 2 Years Old With Venous Thromboembolism (VTE)

This is an observational study in which only data are collected from participants receiving their usual treatment. The study is done in children under 2 years old with venous thromboembolism (VTE). VTE is a condition in which blood clots form in the veins, usually in the leg. This can cause pain and swelling. The clot can also break apart and travel in the blood to the lungs where it can block the blood flow. This can be life threatening. Rivaroxaban is approved for doctors to prescribe to children with VTE, but there is limited information about how it is used, how well it works, and how safe it is in children under 2 years old. Children in this study are already receiving or will receive rivaroxaban or other currently used medicines for VTE from their doctor according to the approved product information. The purpose of this study is to collect information on the pattern of use and safety of rivaroxaban and other standard medicines for VTE in children under 2 years old. The main information that researchers will collect in this study: * Age, gender, and other information about the child and their illness * Type of VTE treatment given to the child * Occurrence of medically important bleeding and its severity Further information that researchers will collect: * Changes in the characteristics of the children given VTE treatment (e.g., changes in the age range of children given VTE treatment) and changes in the treatment pattern for VTE * Return of VTE symptoms * Types of doctors who prescribe VTE treatment and their set-up (e.g., special clinics versus hospitals) Besides this data collection, no further tests or examinations are needed in this study. The data for this study will be collected from electronic health records and health insurance claims data until 2026. Researchers will observe each child during treatment until: * end of the anticoagulation treatment period e.g. discontinuation of all study drugs, * their information is no longer available, or * the study ends.

An Observational Study in the United States to Learn How Venous Thromboembolism, Disseminated Intravascular Coagulation, and Sepsis Are Related

This is an observational study in which data already collected from people with venous thromboembolism (VTE) due to sepsis (blood poisoning) are studied. These people were hospitalized in an intensive care unit (ICU) and may or may not have had disseminated intravascular coagulation (DIC). In this observational study, only observations are made without participants receiving any advice or changes to their healthcare. VTE is a condition that occurs when blood clots form in the veins, which can be dangerous. DIC is a serious blood disorder that can cause clots throughout the body, blocking blood flow. People who have sepsis are at a higher risk of developing both VTE and DIC. Researchers wanted to know if people who have sepsis developed DIC before developing VTE. To prevent VTE in people with sepsis, it is important to know how severe the sepsis is, how it progresses, and whether DIC is also present or not. In this study, researchers will assess patient data from a medical database in the United States (US). The main purpose of this study is to learn if there is a relationship between sepsis, DIC, and VTE. To do this, researchers will divide the participants with VTE due to sepsis into three groups as follows: * participants who were diagnosed with DIC based on the extent of blood clotting * participants who likely had DIC but it was not diagnosed * participants who did not develop DIC during the same hospital visit The researchers will collect the following information: * the number of participants who had VTE due to sepsis also had DIC * the change in participants' laboratory results and vital signs, such as heart rate and blood pressure, from the time their sepsis was diagnosed to the time their VTE and DIC were diagnosed The researchers will study the data collected between January 2007 and December 2021. The data will come from the participants' information stored in a database called the Optum VTE EHR which collects patient medical data from hospitals across the US. In this study, only available data from routine care are collected. No visits or tests are required as part of this study.

RIVAroxaban Versus Low-molecular Weight Heparin in Patients With Lower Limb Trauma Requiring Brace or CASTing

Lower limb trauma requiring immobilization is a very frequent condition that is associated with an increased risk of developing venous thromboembolism (VTE). The TRiP(cast) score has been developed to provide individual VTE risk stratification and help in thromboprophylactic anticoagulation decision. The recent CASTING study had confirmed that patients with a TRiP(cast) score \<7 have a very low risk of VTE and could be safely manage without prophylactic treatment. Conversely, patients with a score ≥ 7 have a high-risk of VTE and require a prophylactic anticoagulant treatment. Low molecular weight heparins (LMWH) have been shown to be effective in this indication. However, in the CASTING study, the 3-month symptomatic VTE rate was 2.6% in this subgroup despite LMWH prophylactic treatment. This result suggests that LMWH are not sufficiently effective in this particular subgroup of high-risk patients. Direct oral anticoagulants, and in particular rivaroxaban, may be an effective and safe alternative to LMWH. In the PRONOMOS study, comparing LMWH with rivaroxaban in patients who had undergone non-major lower limb surgery, the relative risk of symptomatic VTE was 0.25 (95% CI = 0.09 - 0.75) in favor of rivaroxaban 10mg. No significant increase in bleeding was found. In addition, as LMWH treatment requires subcutaneous daily injections, the use of rivaroxaban may positively impact patients' quality of life as well as being effective in medico-economic terms. The aims of this study are to demonstrate that rivaroxaban is at least as effective, easier to use and more efficient than LMWH in patients with trauma to the lower limb requiring immobilisation and deemed to be at risk of venous thromboembolism (TRiP(cast) score ≥ 7). High-risk patients are randomized to receive either rivaroxaban or LMWH. They are followed up at 45 days and 90 days to assess the occurrence of thrombotic events or bleeding, as well as their satisfaction with the treatment received.

Comparison of Bleeding Risk Between Rivaroxaban and Apixaban for the Treatment of Acute Venous Thromboembolism

Apixaban and rivaroxaban have been compared to standard therapy for treatment of acute symptomatic venous thromboembolism (VTE) in randomized controlled trials (RCTs), and are both approved by Health Canada. No safety or efficacy data is available from direct head-to-head comparison of these two anticoagulants. Lawsuits in the United States over bleeding events, patient perceptions, and concerns with medication adherence are additional factors highlighting the importance of a comparison trial. This multi-center, pragmatic, prospective, randomized, open-label, blinded end-point (PROBE) trial aims to compare the safety of apixaban and rivaroxaban for the treatment of VTE.

Variations in the Hemostatic System Induced by a Standardized Walking Test

Two groups of patients will be compared: One group of patients with a history of venous thromboembolic disease and one group without. Both groups will be subjected to a walking test and with electrocardiogram measurements and blood tests.

VTE Prevention Following Total Hip and Knee Arthroplasty

Consented patients undergoing elective total hip and total knee arthroplasty will be randomized to receive either aspirin alone or aspirin and rivaroxaban for prevention of venous thromboembolism.

Residual Pulmonary Vascular Obstruction Index Computed With Ventilation/Perfusion SPECT/CT Imaging to Predict the Risk of Venous Thromboembolism Recurrence in Patients With Pulmonary Embolism (PRONOSPECT)

Major risk after pulmonary embolism (PE) is recurrence, fatal in 10% of patients. Patients with PE can be stratified in 3 groups according to the risk of recurrence : very low risk, high risk or Intermediate risk. Little is known about this last group. Anticoagulation is efficient to prevent recurrence but is currently not recommended for patient with an intermediate risk of recurrence. Identifying risk factors of recurrent PE remains a major issue to identify sub-groups of patients who would require lifelong anticoagulation. In 30-40% of cases, PE patients develop residual pulmonary vascular obstruction (RPVO), which has been found to be associated with an increased recurrence risk. This last observation was mostly reported in patients with unprovoked PE (patients with high risk of recurrence) and RPVO was measured using conventional planar lung scan. In patients with an intermediate risk of recurrence, the impact of RPVO has been much less studied. In addition, the definition of RPVO was variable according to studies and correlation between RPVO burden and recurrence risk has not been clearly demonstrated. This might be explained by the inherent limitation of RPVO quantification using conventional planar imaging, which is only based on a visual estimation on 2-dimensional images. Ventilation/Perfusion Single Photon Emission Computed Tomography (V/Q SPECT/CT) is a new method of scintigraphic image acquisition that offers the advantage of 3-dimensional imaging, enabling more accurate and reproducible quantification of RPVO. The main hypothesis of this study is that in patients with PE at intermediate risk of recurrence, RPVO computed with V/Q SPECT/CT imaging may be an important predictor of recurrence.

Venous Thrombosis Biomarkers in Sickle Cell Disease and Sickle Cell Trait

Background: Venous thromboembolism (VTE) includes the abnormal clotting of blood in a deep vein of the upper or lower limbs (deep vein thrombosis) that may travel to and block a blood vessel in the lung (pulmonary embolism). Some people with sickle cell disease (SCD)-a red blood cell disorder-seem to be at greater risk for developing these blood clots. Researchers want to study the blood of people with SCD and VTE as well as healthy people to develop better treatments to prevent blood clots. Objective: To study blood clotting in SCD because it is the most common cause of vascular death after a heart attack or stroke. Eligibility: People ages 18-80 who have SCD (with or without a history of blood clots) or the trait for SCD, and healthy volunteers Design: Participants will be screened with medical history, physical exam, and medical records review. They will give blood samples. Participants will have phone calls either every 3 months or once a year, for 2 years. They will give updates on their health. They may give additional medical records. The phone calls may last up to 30 minutes. If participants have a VTE or pain crisis episode, they may visit the Clinical Center. These visits may last up to 4 hours. They will repeat the screening tests and give blood samples. Some participants may be invited to take part in blood studies. After 2 years, some participants will have a follow-up visit at the Clinical Center. Participation will last for about 2 years.

Statins to Prevent Cancer Associated Blood Clots

Patients with cancer are at high risk for life-threatening venous thromboembolism (VTE) yet rarely receive anticoagulant prophylaxis due to bleeding risks. Thus, effective prophylaxis in oncology requires a method to reduce VTE without increasing hemorrhage. The primary aim of the Statin Therapy to Prevent Cancer Associated Venous Thromboembolism (STAT-CAT) trial is to test whether rosuvastatin 20 mg daily for 12 months compared to placebo can safely prevent VTE in patients with newly diagnosed or recently relapsed cancer who are at increased thrombotic risk, are not planned to be anticoagulated, and who do not otherwise take statin therapy.

A Performance Evaluation of the LumiraDx Point Of Care D-dimer Assay

In patients with symptoms of Venous Thromboembolism (VTE) (mainly deep vein thrombosis (DVT) or pulmonary embolism (PE)), the study will evaluate the agreement between the D-Dimer measurements from the LumiraDx POC D-Dimer assay and a reference method, as an aid in diagnosis, assessment and exclusion of DVT and PE.

THRomboprophylaxis in Individuals Undergoing Superficial endoVEnous Treatment (THRIVE)

Endovenous interventions are keyhole operations for varicose veins that are carried out from within the vein itself. Varicose veins are enlarged veins close to the surface of the skin. They are connected to the bigger deeper veins in the leg (known as deep veins). Because of this, operations to close the varicose veins can increase the chance of a blood clot forming in the deep veins. Blood clots in the deep veins happen in around 1 in 50 people after endovenous operations. A clot in the leg can cause swelling, pain, and other long-term problems. If a clot in the leg breaks off and travels to the lungs, it can cause problems with the lung' ability to move oxygen from the air into the blood and may, in rare cases, be life threatening. Varicose vein procedures may carry a slightly higher risk of blood clot formation, and we are currently unsure if current clot reducing medicines are beneficial in preventing blood clots in people having varicose vein procedures. This study will investigate if it is worthwhile prescribing medicines to reduce blood clots after varicose vein procedures.