Efficacy of Adjusted Clopidogrel Dose in Patients With Insufficient Platelet Inhibition

Sponsor

University Heart Center Freiburg - Bad Krozingen (Other)

Overall Status

Completed

CT.gov ID

NCT00302913

Collaborator

(none)

120

Enrollment

Location

Duration (Months)

20.1

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

This study is a prospective, single-center evaluation of the efficacy of clopidogrel dose adjustment in patients with insufficient platelet inhibition after elective coronary stent implantation.

Condition or Disease	Intervention/Treatment	Phase
Coronary Artery Disease Drug Resistance	Drug: Adjustment of clopidogrel dose	N/A

Detailed Description

Background: The EXCELSIOR trial demonstrated a 7-fold increased risk for death, myocardial infarction and target vessel reintervention within 30 days in patients with platelet inhibition below median of study cohort after a bolus dose of 600 mg of clopidogrel. The median of platelet inhibition in this cohort was 14 % optical aggregation after stimulation with 5 µM ADP.

Aim: To evaluate the efficacy of clopidogrel dose adjustment in patients with insufficient platelet inhibition after elective coronary stent implantation

Methods: This prospective, single-center study will evaluate antiplatelet effects in 120 patients receiving a bolus dose of 600 mg of clopidogrel before undergoing elective coronary stent implantation. Platelet inhibition will be evaluated 24 hours, 14 and 28 days after coronary intervention using optical aggregometry (5 µM ADP) and determination of surface protein expression by flow cytometry (P-Selectin, gp55, activated GP IIb/IIIa). If 24 hours after coronary stent implantation optical aggregation is >14 %, patients will receive an additional bolus dose of 300 mg of clopidogrel, followed by a daily dose of 150 mg for at least 28 days. If optical aggregation at this point of time is ≤14 % patients will receive a daily dose of 75 mg of clopidogrel. No further dose adjustments during follow up will be performed.

Hypothesis: Adjustment of clopidogrel dose in patients with insufficient platelet inhibition determined by optical aggregometry will provide a comparable antiplatelet effect as in patients with sufficient platelet inhibition after coronary stent implantation.

Study Design

Study Type:

Interventional

Allocation:

Non-Randomized

Intervention Model:

Parallel Assignment

Masking:

None (Open Label)

Primary Purpose:

Treatment

Official Title:

Efficacy of Adjusted Clopidogrel Dose in Patients With Insufficient Platelet Inhibition After Elective Coronary Stenting

Study Start Date :

Dec 1, 2005

Study Completion Date :

Jun 1, 2006

Outcome Measures

Primary Outcome Measures

Antiplatelet effect after fourteen and twenty-eight days determined by optical aggregometry after stimulation with ADP []

Secondary Outcome Measures

Antiplatelet effect after fourteen and twenty-eight days determined by flow cytometric evaluation of surface protein expression after stimulation with ADP []
Major cardiac events within thirty days (death, myocardial infarction, target vessel reintervention) []
Bleeding and vascular access site complications within thirty days []
Drug-drug interaction of clopidogrel with concomitant treatment []

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years and Older

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Patients undergoing elective coronary stenting
Pretreatment with a bolus dose of 600mg of clopidogrel at least 2 hours prior to coronary stent implantation
Pretreatment with aspirin ≥ 100 mg per day for at least 7 days
Age > 18 years
Written consent