Biological Factors Associated With Subclinical Valvular Thrombosis

Study Overview
=================
Brief Summary
-----------------
A prospective, multicentric cohort study including 166 patients with symptomatic aortic stenosis treated with transcatheter aortic valve implantation (TAVI). - The main objective is to determine whether the high residual platelet reactivity rates in patients undergoing TAVI is associated with the occurrence of clinical and / or subclinical prosthetic valve thrombosis measured by echocardiography and multi-slice computerized tomography

Detailed Description
-----------------
For the purpose of the study, platelet reactivity will be measured with the commercial kit PLT VASP/P2Y12 at baseline, 1day and 3 months postprocedure. Secondary objectives include: -Determine the variability of platelet aggregation measured at baseline before the procedure, 1-day post-procedure and at 3-6 and 1 year follow-up. To determine whether the pro-thrombotic inflammatory response measured by the CD14 + and CD16 + quantification observed after TAVI is associated with the appearance of prosthetic thrombosis. To evaluate the Correlation of Von Willebrand factor levels and distribution of Von Willebrand multimers with the appearance of prosthetic thrombosis at baseline before the procedure, 1-day post-procedure and at 3, 6 months follow-up and 1 year. To determine whether the residual platelet reactivity rates in patients undergoing TAVI are associated with the occurrence of clinical events, at baseline before the procedure, 1-day post-procedure and at 3,6 months follow-up and 1 year To evaluate the clinical factors associated with the appearance of early prosthetic thrombosis.

Official Title
-----------------
Evaluation of Biological Factors Associated With Subclinical Valvular Thrombosis in pAtients With Severe aoRtic Stenosis Undergoing TAVI: START Trial

Conditions
-----------------
Aortic Stenosis

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients with severe symptomatic aortic stenosis who it was accepted to be treated with TAVI by a multidisciplinary team Heat Team. TAVI was successfully implanted (according to Valve Academic Research Consortium II criteria) and are under treatment with double antiplatelet therapy. Signed informed consent to participate in this study. Exclusion Criteria: Age under 18 years and pregnant or of childbearing age. Acute Recent stroke recent <14 days before TAVI. The patients with proven allergy to aspirin, clopidogrel Patients that after TAVI cannot undergo a double antiplatelet regimen for 6 months due to a new post-TAVI medical indication or are anticoagulated. Knowledge of pregnancy or lactation Thrombocytopenia (<50,000 platelets U / L) well documented and clinically relevant. The patients with documented moderate or severe hepatic insufficiency Severe chronic renal insufficiency with creatinine clearance <30 ml / min. The patients who can not attend the follow-up visits scheduled in the study

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

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

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

Study Plan
=================
How is the study designed?
-----------------
What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The association between high residual platelet reactivity rates in patients undergoing TAVI with the occurrence of clinical and / or subclinical prosthetic valve thrombosis | platelet reactivity will be measured with the commercial kit platelet Vasodilator Stimulated Phosphoprotein (VASP)/P2Y12 and subclinical valve thrombosis by transthoracic echocardiography and multi-slice computerized tomography | at 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To measure the variability of platelet aggregation | platelet aggregation | at baseline, 1 day post-procedure and at 3-6 months and 1 year follow-up. | 
| To quantify the pro-thrombotic inflammatory response | measured by serum levels of (cluster of differentiation 14) CD14 + and (cluster of differentiation 16) CD16 + | at baseline, 1 day post-procedure and at 3, 6 months and 1 year follow-up. | 
| To correlate of Von Willebrand factor levels and distribution of Von Willebrand factor multimers with the appearance of prosthetic thrombosis | Serum Von Willebrand factor levels and distribution of Von Willebrand factor multimers with the appearance of prosthetic thrombosis assessed by transthoracic echocardiography or multi-slice computerized tomography | at baseline, 1 day post-procedure and at 3, 6 months and 1 year follow-up. | 
| To correlate residual platelet reactivity with clinical events | platelet aggregation | at baseline, 1 day post-procedure and at 3, 6 months and 1 year follow-up. | 
| To evaluate clinical factors associated with the appearance of early prosthetic thrombosis. | to perform Multislice computerized tomography and clinical follow-up | multi slice computerized tomography at 3 month and clinical up to 1 year. |