Platelet Reactivity in Patients on a Thienopyridine and Awaiting Coronary Artery Bypass Grafting (Serial CABG)

The primary objective of this exploratory cohort study is to describe levels of platelet reactivity in patients on a thienopyridine awaiting coronary artery bypass grafting (CABG).

Study Overview

• Status: Completed
• Conditions: Complication of Coronary Artery Bypass Graft; Peri-operative Hemorrhage or Hematoma; Post Operative Bleeding
• Intervention / Treatment: Other: Platelet reactivity assessment

Detailed Description

The recent emergence of platelet reactivity testing as a potential option for evaluating the degree of platelet inhibition promises to add another level of understanding to our concept of CABG-related bleeding. There is an emerging literature that links high levels of platelet reactivity with adverse clinical events, primarily in patients on clopidogrel.

For example, studies of the VerifyNow P2Y12 platelet function assay have shown that Platelet Reactivity Units (PRU) > 235-240 in patients on clopidogrel therapy appears to predict cardiovascular events.15,16 There is a paucity of literature, however, on the use of platelet reactivity testing to predict bleeding events and complications. In other words, if excessively high levels of platelet reactivity predict ischemic events, do excessively low levels of platelet reactivity predict bleeding events? This is an especially relevant question, given the emergence of prasugrel as a therapeutic option.

The investigators therefore propose an exploratory cohort study of patients receiving a thienopyridine (clopidogrel or prasugrel) and undergoing CABG, in order to describe levels of platelet reactivity in such patients by using a variety of platelet function tests.

• Study Type: Interventional
• Enrollment (Actual): 75
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Patients ≥ 18 years old from both genders.
2. Taking maintenance thienopyridine therapy within 5 days of surgery OR received a loading dose of thienopyridine therapy within 48 hours of surgery for CABG.
3. Referred for CABG (which is scheduled to be performed during the current admission).

Exclusion Criteria:

1. Known allergies to aspirin, clopidogrel, or prasugrel.
2. Use of a glycoprotein (GP) IIb/IIIa inhibitor within 8 hours of initial platelet reactivity testing.
3. Patient known to be pregnant or lactating.
4. Patient with known history of bleeding diathesis or currently active bleeding.
5. Platelet count <100,000/mm the day of initial blood draw.
6. Hematocrit <25% the day of initial blood draw.
7. On warfarin therapy at the time of initial blood draw.
8. Known blood transfusion within the preceding 10 days of the blood draw.
9. Patients treated with non-steroidal anti-inflammatory drugs (NSAIDS) within the previous 5 days.
10. Plan for patient to be discharged before undergoing CABG.
11. Any significant medical condition that, in the investigator's opinion, may interfere with the patient's optimal participation in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: CABG	Other: Platelet reactivity assessment; Platelet reactivity, as measured by the Chrono-log Lumi-Aggregometer, VerifyNow P2Y12 assay, and Vasodilator Stimulated Phosphoprotein (VASP) flow cytometry assay.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serial levels of platelet reactivity, as assessed with the Chrono-log Lumi-Aggregometer	Serial levels of platelet reactivity, as assessed with the Chrono-log Lumi-Aggregometer, which measures levels of light transmittance after stimulation with ADP to estimate levels of platelet aggregation	Duration of hospital stay; average hospital stay of 1 week
Perioperative rates of bleeding complications	Perioperative rates of bleeding complications: need for reoperation because of bleeding; need for perioperative red blood cell transfusion (units of packed red blood cells); rates of TIMI, GUSTO, and nuisance bleeding; quantity of postoperative drainage (mL)	Duration of hospital stay; average hospital stay of 1 week

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serial levels of platelet reactivity, as assessed with the VerifyNow P2Y12 assay	Serial levels of platelet reactivity, as assessed with the VerifyNow P2Y12 assay, which measures platelet reactivity units (PRUs)	Duration of hospital stay; average hospital stay of 1 week
Serial levels of platelet reactivity, as assessed with the Vasodilator Stimulated Phosphoprotein (VASP) assay	Serial levels of platelet reactivity, as assessed with the Vasodilator Stimulated Phosphoprotein (VASP) assay, which measures percentage of platelet reactivity inhibition (PRI) by flow cytometry of the VASP-P protein	Duration of hospital stay; average hospital stay of 1 week

Collaborators and Investigators

• Sponsor: Medstar Health Research Institute

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2010
• Primary Completion (Actual): February 1, 2016
• Study Completion (Actual): July 1, 2016

Study Registration Dates

• First Submitted: July 22, 2011
• First Submitted That Met QC Criteria: July 29, 2011
• First Posted (Estimate): August 1, 2011

Study Record Updates

• Last Update Posted (Actual): March 16, 2021
• Last Update Submitted That Met QC Criteria: March 11, 2021
• Last Verified: June 1, 2018

More Information

Terms related to this study

• Keywords: CABG; Platelet reactivity; Perioperative and in hospital bleeding
• Additional Relevant MeSH Terms: Pathologic Processes; Postoperative Complications; Intraoperative Complications; Hemorrhage; Blood Loss, Surgical; Postoperative Hemorrhage; Hematoma
• Other Study ID Numbers: Serial CABG