Long-Term Post Thrombotic Syndrome Assessment (CELEST Long Term).

Study Overview
=================
Brief Summary
-----------------
The CELEST Long term is a prospective study, assessing the very long term risk of post thrombotic syndrome (PTS) in patients enrolled in the CELEST double-blind RCT. All patients enrolled in CELEST RCT will benefit from a 7-year follow-up visit conducted over the phone. The primary objective is to assess the proportion of patients with moderate-severe PTS assessed with the patient reported Villalta score and the 2 main secondary objectives are to assess predictors of moderate to severe PTS and the impact of initial compression stockings strength (25mmHg vs. 35mmHg) on the development of moderate-severe PTS. Up to 288 patients may participate. The investigators believe that this study has the potential to significantly improve the knowledge on the epidemiology of burdensome PTS and on the impact of different initial compression stockings strengths on the risk of PTS.

Detailed Description
-----------------
The CELEST double blind RCT demonstrated that 25mmHg elastic compression stockings (ECS) were non inferior to 35mmHg ECS to prevent post thrombotic syndrome (PTS) 2 years after a first proximal deep vein thrombosis (DVT). Likely because of lack of statistical power the investigators were not able to demonstrate that 25mmHg ECS were superior in the overall RCT population and that 35mmHg ECS were superior in patients optimally adherent to ECS. Furthermore, few data are available on the very long term (>5 years). The CELEST Long term is a prospective study, assessing the very long term risk of PTS in patients enrolled in the CELEST RCT. All patients enrolled in CELEST RCT and willing to participate are eligible and will benefit from a 7-year follow-up visit conducted over the phone. Primary objective is to assess the proportion of patients with moderate-severe PTS defined as a patient reported Villalta score (PRVS) ≥10 or a venous leg ulcer ipsilateral to index DVT. Secondary objectives include predictors of moderate to severe PTS, impact of initial ECS strength on the development of moderate-severe PTS, impact of anticoagulant treatment (type and duration) on the development of moderate to severe PTS, proportion of PTS (defined as PRVS≥5 or ipsilateral leg ulcer) and impact of PTS on patient's QOL. Study should last 1 year and up to 288 patients may participate. The investigators believe that this study has the potential to significantly improve the knowledge on the epidemiology of burdensome PTS and on the impact of different initial CE strengths on the risk of PTS.

Official Title
-----------------
Determine the Proportion of Patients With Disabling Post Thrombotic Syndrome (Moderate or Severe) in the Long Term Within the Cohort of Patients Who Participated in the Trial CELEST Therapy.

Conditions
-----------------
Post Thrombotic Syndrome

Intervention / Treatment
-----------------
* Other: Phone call


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients enrolled and followed in the CELEST RCT* Exclusion Criteria: Patients who withdrew consent or died during the 2-year follow-up of the CELEST RCT. Patients who decline or are unable to participate (including severe memory loss issues) to the long-term follow-up CELEST RCT main inclusion/exclusion criteria were: adult (>18 years at time of enrolment) patients first unilateral acute symptomatic proximal lower limb DVT

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 100 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| 35mmHg ECS<br>Subjects with first proximal DVT allocated to wear 35 mmHg elastic compression stockings (ECS) for 2 years during the CELEST RCT | Other: Phone call<br>* This follow-up will be conducted over the phone and by mail (some questionnaire may be sent by patient, as per his/her preference)<br>|
| 25mmHg ECS<br>Subjects with first proximal DVT allocated to wear 25 mmHg elastic compression stockings (ECS) for 2 years during the CELEST RCT | Other: Phone call<br>* This follow-up will be conducted over the phone and by mail (some questionnaire may be sent by patient, as per his/her preference)<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of patients with moderate-severe PTS in the whole cohort | PTS defined with the patient reported Villalta score (PRVS). Moderate-severe PTS: PRVS≥10 or presence of a venous leg ulcer in the leg ipsilateral to index DVT The Villalta score consists in 11 questions (5 on subjective symptoms and 6 on objective signs). Each question is coded between 0 and 3 (0: none - 1: mild - 2: moderate - 3: severe). The total score is the sum of the 11 questions and therefore ranges from 0 to 33, where a high value indicates a high level of disability. An additional question asks about the presence of ulcers. If the calculated score is < 15, a value of 15 is assigned to the ulcer score. The thresholds used are as follows: presence of PTS if Villalta ≥ 5 presence of disabling PTS (moderate, severe) if Villalta ≥ 10 presence of severe PTS if Villalta ≥ 15 | At the phone follow-up up to 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Predictors of moderate-severe PTS | Predictors of moderate-severe PTS in the whole cohort | Since enrolment in the CELEST CRT | 
| Impact of initial ECS strength on the development of moderate-severe PTS | Comparison of proportion of moderate-severe PTS between patients randomized in the 25mmHg ECS vs. 35mmHg ECS group | Since enrollment in the CELEST study | 
| Impact of initial type of ECS on the development of moderate-severe PTS | Comparison of proportion of moderate-severe PTS between patients who chose to wear above knee vs. below knee ECS during CELEST RCT | Since enrollment in the CELEST study | 
| Impact of adherence to RCT's ECS on the development of moderate-severe PTS | Comparison of proportion of moderate-severe PTS according to adherence to ECS during CELEST RCT | Since enrollment in the CELEST study | 
| Assessment of the use of ECS after the end of the RCT in terms of use, strength, length, adherence, duration | Description of the use of ECS among study participants since the end of their participation in the CELEST RCT | Since enrolment in the CELEST study with focus on the period end of RCT to long-term follow-up | 
| Factors influencing the the decision to continue, stop or resume ECS | Description of the reasons that led to the decision to continue, stop or resume ECS | During the 2-year celest study and during the long-term follow-up | 
| Impact of anticoagulant treatment on the development of moderate-severe PTS | Comparison of proportion of moderate-severe PTS according to type and duration of anticoagulant treatment during CELEST RCT | During the 2-year celest study and during the long-term follow-up | 
| Proportion of patients with any PTS | PTS present if PRVS≥5 or presence of a venous leg ulcer in the leg ipsilateral to index DVT | At the phone follow-up up to 3 months | 
| Predictors of any PTS | Predictors of PTS (defined as a PRVS≥5 or presence of a venous leg ulcer in the leg ipsilateral to index DVT) in the whole cohort | At the phone follow-up up to 3 months | 
| Proportion of patients who developed a serious adverse events (SAE) in the cohort | SAEs assessed are death, venous thromboembolic recurrence, major bleeding and peripheral arterial disease. SAEs are defined according to the International Society on Thrombosis and Haemostasis criteria. These events will be adjudicated by the study adjudication committee | During the 2-year celest study and during the long-term follow-up | 
| Impact of PTS on patients' quality of life | Comparison of QOL scores according to the presence or absence of PTS and its severity; QOL will be assessed using CIVIQ-20 questionnaire | At the phone follow-up up to 3 months | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Post thrombotic syndrome, Elastic compression stockings, long-term follow-up, Deep vein Thrombosis