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Aspirin Resistance and Stroke Risk: Platelet Function Analysis in Patients With Ischemic Events

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ClinicalTrials.gov Identifier: NCT01586975
Recruitment Status : Completed
First Posted : April 27, 2012
Results First Posted : December 3, 2015
Last Update Posted : December 31, 2015
Sponsor:
Information provided by (Responsible Party):
Northwestern University

Study Type Interventional
Study Design Allocation: Non-Randomized;   Intervention Model: Parallel Assignment;   Masking: None (Open Label);   Primary Purpose: Treatment
Conditions Stroke
Myocardial Infarctions
Interventions Drug: Clopidogrel
Drug: Aspirin 81 mg
Drug: Aspirin >300 mg
Enrollment 93
Recruitment Details Patients with cerebrovascular disease and taking one or more antiplatelet medication were consented for study participation from 2007 though 2010. Patients were recruiting on the inpatient stroke unit at Northwestern Memorial Hospital and seen in the outpatient stroke clinic.
Pre-assignment Details  
Arm/Group Title Clopidogrel 75 mg Aspirin 81 mg Aspirin > 300 mg
Hide Arm/Group Description Clopidogrel 75 mg QD Aspirin 81 mg QD Aspiring > 300 mg QD
Period Title: Overall Study
Started 15 32 46
Completed 15 32 46
Not Completed 0 0 0
Arm/Group Title Clopidogrel 75 mg Aspirin 81 mg Aspiring >300 mg Total
Hide Arm/Group Description Clopidogrel 75 mg QD Aspirin 81 mg QD Aspirin >300 mg QD Total of all reporting groups
Overall Number of Baseline Participants 15 32 46 93
Hide Baseline Analysis Population Description
[Not Specified]
Age, Customized  
Mean (Full Range)
Unit of measure:  Years
Number Analyzed 15 participants 32 participants 46 participants 93 participants
60.6
(37 to 83)
67.4
(36 to 93)
56.2
(21 to 87)
60.7
(21 to 93)
Sex: Female, Male  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 15 participants 32 participants 46 participants 93 participants
Female
9
  60.0%
16
  50.0%
26
  56.5%
51
  54.8%
Male
6
  40.0%
16
  50.0%
20
  43.5%
42
  45.2%
Race (NIH/OMB)  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 15 participants 32 participants 46 participants 93 participants
American Indian or Alaska Native
0
   0.0%
0
   0.0%
0
   0.0%
0
   0.0%
Asian
0
   0.0%
2
   6.3%
2
   4.3%
4
   4.3%
Native Hawaiian or Other Pacific Islander
0
   0.0%
0
   0.0%
0
   0.0%
0
   0.0%
Black or African American
2
  13.3%
4
  12.5%
7
  15.2%
13
  14.0%
White
13
  86.7%
25
  78.1%
37
  80.4%
75
  80.6%
More than one race
0
   0.0%
0
   0.0%
0
   0.0%
0
   0.0%
Unknown or Not Reported
0
   0.0%
1
   3.1%
0
   0.0%
1
   1.1%
Region of Enrollment  
Measure Type: Number
Unit of measure:  Participants
United States Number Analyzed 15 participants 32 participants 46 participants 93 participants
15 32 46 93
1.Primary Outcome
Title PFA1
Hide Description Platelet Function Analysis (PFA) lab results: PFA was performed using the PFA 100 device (Dade-Behring), which uses a higher sheer stress flow cytometry paradigm to measure the time in seconds to closing of an aperture. Normal is defined as <172 seconds."
Time Frame 3-6 months (Collected once between regulalary scheduled follow-up visit between 3-6 months)
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title Clopidogrel 75 mg Aspirin 81 mg Aspirin > 300 mg
Hide Arm/Group Description:
Clopidogrel 75 mg QD
open label Aspirin
open-label Aspirin
Overall Number of Participants Analyzed 15 32 46
Mean (Standard Error)
Unit of Measure: seconds
202.0  (27.1) 271.1  (14.9) 234.7  (13.4)
Show Statistical Analysis 1 Hide Statistical Analysis 1
Statistical Analysis Overview Comparison Group Selection Clopidogrel 75 mg, Aspirin 81 mg, Aspirin > 300 mg
Comments Kruskal-Wallis non-parametric ANOVA test
Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value 0.0742
Comments p-value is not adjusted, and no a priori threshold was used
Method Kruskal-Wallis
Comments [Not Specified]
Time Frame Patients were monitored via routine clinic/office visits to determine if they had an ischemic vascular event or hemorrhagic event. These follow-up visits were scheduled every 3-6 months as per their regularly scheduled clinic follow-up visits.
Adverse Event Reporting Description [Not Specified]
 
Arm/Group Title Clopidogrel 75 mg Aspirin 81 mg Aspirin >300 mg
Hide Arm/Group Description Clopidogrel 75 mg QD Aspirin 81 mg QD Aspirin >300 mg QD
All-Cause Mortality
Clopidogrel 75 mg Aspirin 81 mg Aspirin >300 mg
Affected / at Risk (%) Affected / at Risk (%) Affected / at Risk (%)
Total   --/--      --/--      --/--    
Show Serious Adverse Events Hide Serious Adverse Events
Clopidogrel 75 mg Aspirin 81 mg Aspirin >300 mg
Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events
Total   0/15 (0.00%)      1/32 (3.13%)      2/46 (4.35%)    
Cardiac disorders       
MI  [1]  0/15 (0.00%)  0 0/32 (0.00%)  0 1/46 (2.17%)  1
Vascular disorders       
Clinical Stroke  [2]  0/15 (0.00%)  0 1/32 (3.13%)  1 0/46 (0.00%)  0
TIA  [3]  0/15 (0.00%)  0 0/32 (0.00%)  0 1/46 (2.17%)  1
Indicates events were collected by systematic assessment
[1]
one patient suffered a MI
[2]
one patient suffered a clinical stroke
[3]
one patient suffered from a TIA
Show Other (Not Including Serious) Adverse Events Hide Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events 0%
Clopidogrel 75 mg Aspirin 81 mg Aspirin >300 mg
Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events
Total   2/15 (13.33%)      3/32 (9.38%)      2/46 (4.35%)    
Gastrointestinal disorders       
GI bleeding  [1]  1/15 (6.67%)  1 1/32 (3.13%)  1 0/46 (0.00%)  0
Immune system disorders       
Bruising  [2]  1/15 (6.67%)  1 0/32 (0.00%)  0 0/46 (0.00%)  0
Vascular disorders       
Nose bleeds  [3]  0/15 (0.00%)  0 2/32 (6.25%)  2 2/46 (4.35%)  2
Indicates events were collected by systematic assessment
[1]
minor GI bleeding/blood in stool
[2]
minor bruising
[3]
4 patients suffered from nose bleeds
Certain Agreements
Principal Investigators are NOT employed by the organization sponsoring the study.
There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.
Results Point of Contact
Name/Title: Northwestern University
Organization: Northwestern University
Phone: 312.503.4394
Responsible Party: Northwestern University
ClinicalTrials.gov Identifier: NCT01586975     History of Changes
Other Study ID Numbers: Aspirin Resistance and Stroke
IRB#0996-007 FUND#7810 ( Other Identifier: Northwestern Memorial Hospital )
First Submitted: August 3, 2011
First Posted: April 27, 2012
Results First Submitted: June 29, 2015
Results First Posted: December 3, 2015
Last Update Posted: December 31, 2015