Relationship Between Level of Hemoglobin A1c and Platelet Function in Patients Undergoing Cardiac Surgery

Study Overview
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Brief Summary
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The aim of this study is to evaluate whether increased level of hemoglobin A1c (HbA1c) correlates to higher level of platelet reactivity assessed by impedance aggregometry in patients with diabetes mellitus undergoing elective coronary artery bypass grafting (CABG).

Detailed Description
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This study will be conducted at Cardiac Surgery Department, University Hospital Center Zagreb. It will be conducted in prospective observational fashion. Diabetic patients undergoing isolated, primary on-pump CABG will be consecutively recruited. Patients requiring urgent procedure will be excluded. Blood samples, both for conventional lab. findings (including HbA1c) and impedance aggregometry will be drawn prior to surgery and postoperatively on daily basis. Cohort sample will be divided into two subgroups according to HbA1c level (Group 1 with HbA1c < 7% and Group 2 with HbA1c ≥ 7%, respectively). Respective subgroups will be compared for basic demographic data, laboratory findings including those obtained using platelet function testing, and for clinical outcomes, respectively. Multiple-electrode aggregometry: Whole blood aggregation will be determined using a new-generation impedance aggregometer (Multiplate analyzer; Roche Diagnostics). In brief, when platelets expose receptors on their surface they get activated and stick on the Multiplate sensor wires enhancing the electrical resistance between them. An increase in impedance is expressed in arbitrary area under the curve (AUC) units. Platelet aggregation is determined in response to stimulation with arachidonic acid (ASPI (aspirin-sensitive patients identification) test designed to evaluate the effect to acetylsalicylic acid (ASA)) and adenosine diphosphate (ADP) (ADP test designed to evaluate the effect of thienopyridines, such as clopidogrel).

Official Title
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Relationship Between Level of Glycosylated Hemoglobin and Platelet Function in Patients Undergoing Coronary Artery Bypass Grafting

Conditions
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Diabetes Mellitus, Complication of Coronary Artery Bypass Graft, Blood Platelet Disorders

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing isolated primary on-pump CABG Elective surgery Diabetic patients including insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus NIDDM Patients on antiplatelet therapy (aspirin and/or clopidogrel) pre- and postoperatively Exclusion Criteria: Missing consent Patients with cardiac surgical procedures other than isolated CABG Patients on antiplatelet therapy other than aspirin or clopidogrel Urgent surgery Off-pump CABG Redo CABG
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Group with hemoglobin A1c < 7<br>There will be no intervention administered to the group. The group will be observed for platelet function pre- and postoperatively. | |
| Group with hemoglobin A1c ≥ 7%<br>There will be no intervention administered to the group. The group will be observed for platelet function pre- and postoperatively. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The level of preoperative HbA1c that will be a predictor of the higher prevalence of platelet resistance to the aspirin |  | 4 days after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Differences in perioperative aspirin resistance (AUC, area under the curve) between patients with insulin-dependent diabetes mellitus and patients with non-insulin-dependent diabetes mellitus |  | 4 days after surgery | 
| Correlation between platelet ADP receptors reactivity (AUC) and the type of diabetes |  | 4 days after surgery | 
| Correlation of diabetes duration and platelet reactivity (AUC) |  | 4 days after surgery | 
| The prevalence of major adverse cardiovascular events (MAACE) in patients with HbA1c ≥ 7% |  | 3 months after surgery | 
| Postoperative thoracic drainage in patients with the appropriate glucose regulation (Hba1c<7%) |  | within the first 5 days after surgery | 
| Mortality |  | 3 months after surgery | 
| The level of HbA1c, that will represent the reliable predictor of platelet hyperreactivity and MAACE |  | within the 3 months after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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hemoglobin A1c, coronary artery bypass grafting, impedance aggregometry, platelet reactivity, clinical outcomes