EXERT: Exercise Physiology After Thrombosis

Study Overview
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Brief Summary
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Deep vein thrombosis (DVT) can cause long-term scarring and narrowing of veins. When there is extensive damage to the veins in the legs, groin or abdomen it can affect the way that blood is able to flow back up to the heart. Some patients are left with severe symptoms such as pain, leg swelling and ulcers, and have surgical treatment with nitinol stents to re-open the veins and relieve symptoms. The primary aim of this study is to investigate venous blood flow to the heart during exercise in patients with extensive damage to the veins in the groin and abdomen after DVT, and changes that happen after stenting.

Detailed Description
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Participants will have cardiopulmonary exercise testing, 6 minute walk test and basic blood tests to establish exercise tolerance and rule out other heart and lung conditions. Exercise cardiac MRI will be used to evaluate cardiac function during exercise. All participants will complete generic and disease specific quality of life questionnaires. Participants who are having a stenting procedure will repeat assessments 6-8 weeks after surgery.

Official Title
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Exercise Physiology After Thrombosis (EXERT): a Prospective Single Centre Cohort Study of Cardiovascular and Exercise Physiology in Patients With Previous Venous Thrombosis in the Inferior Vena Cava and Iliofemoral Veins.

Conditions
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Venous Thrombosis Deep (Limbs), Post Thrombotic Syndrome

Intervention / Treatment
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* Diagnostic Test: Cardiopulmonary exercise test (CPET)
* Diagnostic Test: Exercise cardiac MRI
* Other: 6 minute walk test
* Diagnostic Test: Blood tests
* Other: Quality of life questionnaires
* Other: Repeat baseline assessments
* Diagnostic Test: MR venogram


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All groups: ->16 years of age - Consent to participate in the research study and be willing to commit to study requirements, including completion of questionnaires and follow up visits. Group 1: Venous thrombosis/obstruction involving the inferior vena cava >12 months ago. Symptoms of exertional dyspnoea reported by patient. Judged by the chief investigator as suitable for surgical intervention before recruitment to the study. Agree to adhere to therapeutic anticoagulation after surgical intervention. Group 2: Venous thrombosis/obstruction involving the inferior vena cava >12 months ago. Under the clinical care of the deep venous service for surveillance of symptoms. Group 3: Unilateral Iliofemoral venous thrombosis /obstruction >12 months ago. Judged by the chief investigator as suitable for surgical intervention before recruitment to the study. Agree to adhere to therapeutic anticoagulation after surgical intervention. Exclusion Criteria: All groups: DVT or PE in last 12 months Significant or untreated left sided heart disease (eg coronary artery disease, LV dysfunction, valvular abnormalities, congenital heart disease, chronic or paroxysmal arrhythmias) Significant or untreated chronic lung disease (eg asthma, COPD, ILD) Moderate to severe renal disease Moderate to severe liver disease Peripheral arterial disease Significant neurological or musculoskeletal disease Cognitive impairment or learning disabilities Pregnant or planning to become pregnant in next 12 months Active cancer (primary, metastatic or treated within last 6 months) Life expectancy < 2 years or chronic non-ambulatory status. Any other contraindication to exercise. Any contraindications to MRI scanning Inability to provide informed consent or comply with study assessments (e.g. due to cognitive impairment, physical limitations or geographic distance). Group 4: All of the above, plus: Previous DVT or PE Known, or clinical signs of chronic venous disease as judged by the chief investigator e.g. varicose veins, leg ulcers.

Ages Eligible for Study
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Minimum Age: 16 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Venous outflow obstruction extending to inferior vena cava, symptomatic with dyspnoea<br>Baseline assessments Post-operative assessments if applicable | Diagnostic Test: Cardiopulmonary exercise test (CPET)<br>* Cardiopulmonary exercise testing using cycle ergonomenter<br>Diagnostic Test: Exercise cardiac MRI<br>* Exercise cardiac MRI using supine cycle, participants exercised to peak workload as determined by CPET<br>Other: 6 minute walk test<br>* 6MWT<br>Diagnostic Test: Blood tests<br>* FBC, U&E, LFTS<br>Other: Quality of life questionnaires<br>* SF36, EQ5D, VEINES-QoL/Sym<br>Other: Repeat baseline assessments<br>* repeat baseline<br>Diagnostic Test: MR venogram<br>* MRI scan of venous system<br>|
| Venous outflow obstruction extending to inferior vena cava, not symptomatic with dyspnoea<br>Baseline assessments Post-operative assessments if applicable | Diagnostic Test: Cardiopulmonary exercise test (CPET)<br>* Cardiopulmonary exercise testing using cycle ergonomenter<br>Diagnostic Test: Exercise cardiac MRI<br>* Exercise cardiac MRI using supine cycle, participants exercised to peak workload as determined by CPET<br>Other: 6 minute walk test<br>* 6MWT<br>Diagnostic Test: Blood tests<br>* FBC, U&E, LFTS<br>Other: Quality of life questionnaires<br>* SF36, EQ5D, VEINES-QoL/Sym<br>Other: Repeat baseline assessments<br>* repeat baseline<br>Diagnostic Test: MR venogram<br>* MRI scan of venous system<br>|
| Unilateral iliac venous outflow obstruction<br>Baseline assessments Post-operative assessments if applicable | Diagnostic Test: Cardiopulmonary exercise test (CPET)<br>* Cardiopulmonary exercise testing using cycle ergonomenter<br>Diagnostic Test: Exercise cardiac MRI<br>* Exercise cardiac MRI using supine cycle, participants exercised to peak workload as determined by CPET<br>Other: 6 minute walk test<br>* 6MWT<br>Diagnostic Test: Blood tests<br>* FBC, U&E, LFTS<br>Other: Quality of life questionnaires<br>* SF36, EQ5D, VEINES-QoL/Sym<br>Other: Repeat baseline assessments<br>* repeat baseline<br>Diagnostic Test: MR venogram<br>* MRI scan of venous system<br>|
| Age and sex matched controls<br>Baseline assessments | Diagnostic Test: Cardiopulmonary exercise test (CPET)<br>* Cardiopulmonary exercise testing using cycle ergonomenter<br>Diagnostic Test: Exercise cardiac MRI<br>* Exercise cardiac MRI using supine cycle, participants exercised to peak workload as determined by CPET<br>Other: 6 minute walk test<br>* 6MWT<br>Other: Quality of life questionnaires<br>* SF36, EQ5D, VEINES-QoL/Sym<br>Other: Repeat baseline assessments<br>* repeat baseline<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| VO2 max after stenting | As determined by cardiopulmonary exercise testing | 6-8 weeks post surgery | 
| Peak cardiac output during exercise | as determined by exercise cardiac MRI | 6-8 weeks post surgery |