Does Platelet Reactivity Predict Bleeding in Patients Needing Urgent Coronary Artery Bypass Grafting During Dual Antiplatelet Therapy?
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Published on: March 15, 2022
Elisabeth Mahla1, Florian Prueller2, Sylvia Farzi1
1Department of Anesthesiology and Intensive Care Medicine, Medical University of Graz, Graz, Austria.
Insights
Patients undergoing coronary artery bypass grafting (CABG) on dual antiplatelet therapy experience less bleeding with higher platelet reactivity. This study highlights the importance of measuring platelet function to guide surgical timing and reduce CABG-related bleeding risks.
Area of Science:
- Cardiology
- Hematology
- Surgical Research
Background:
- Coronary artery bypass grafting (CABG) is frequently required in patients on dual antiplatelet therapy.
- Platelet reactivity is linked to bleeding after CABG, but optimal thresholds are unknown.
Purpose of the Study:
- To investigate the association between preoperative platelet reactivity and bleeding complications in patients undergoing CABG while on dual antiplatelet therapy.
- To explore potential cutoffs for platelet reactivity to predict bleeding risk.
Main Methods:
- Prospective study of 149 patients on aspirin and a P2Y12 inhibitor before isolated CABG.
- Platelet reactivity assessed preoperatively using light transmittance aggregometry (LTA), VASP assay, Multiplate analyzer, and Innovance PFA2Y.
- Primary endpoint: calculated red blood cell loss.
Main Results:
- Low preoperative platelet reactivity was observed across all assays.
- A significant inverse relationship was found between platelet reactivity tertiles and red blood cell loss (p < 0.004).
- Higher platelet reactivity tertiles showed reduced rates of Bleeding Academic Research Consortium (BARC)-4 bleeding (p = 0.037).
Conclusions:
- Increasing platelet reactivity is associated with decreased red blood cell loss and BARC-4 bleeding in patients undergoing CABG on antiplatelet therapy.
- Objective measurement of platelet function supports current guidelines for determining surgical timing.
Background:
Up to 15% of patients require coronary artery bypass grafting (CABG) during dual antiplatelet therapy. Available evidence suggests an association between platelet reactivity and CABG-related bleeding. However, platelet reactivity cutoffs for bleeding remain elusive. We sought to explore the association between platelet reactivity and bleeding.
Methods:
Patients on aspirin and a P2Y12 receptor inhibitor within 48 hours before isolated CABG (n = 149) were enrolled in this prospective study. Blood was drawn 2 to 4 hours preoperatively and platelet reactivity assessed by light transmittance aggregometry (LTA), vasodilator-stimulated phosphoprotein (VASP) assay, Multiplate analyzer and Innovance PFA2Y. The primary endpoint was calculated red blood cell loss computed as follows: (blood volume × preoperative hematocrit × 0.91) - (blood volume × hematocrit × 0.91 on postoperative day 5) + (mL of transfused red blood cells × 0.59).
Results:
Preoperative platelet reactivity was low [median (interquartile range): LTA: 20 (9-28)%; VASP-PRI: 39 (15-73)%; Multiplate adenosine phosphate test: 16 (12-22) U∗min]. Innovance PFA2Y ≥300 seconds, 72%. Median (IQR) red blood cell loss in patients in first the LTA tertile was 1,449 (1,020 to 1,754) mL compared with 1,107 (858 to 1,512) mL and 1,075 (811 to 1,269) mL in those in the second and third tertiles, respectively (p < 0.004). Bleeding Academic Research Consortium (BARC)-4 bleeding differed between tertiles (62% versus 46% versus 36%; p = 0.037). In a multivariable linear regression model, aspirin dose ≥300 mg, cardiopulmonary bypass time, EuroSCORE, and tertile distribution of platelet reactivity were significantly associated with red blood cell loss.
Conclusions:
A gradual decrease in red blood cell loss and BARC-4 bleeding occurs with increasing platelet reactivity in patients on antiplatelet therapy undergoing CABG. Our findings support current guidelines to determine time of surgery based on an objective measurement of platelet function (Platelet Inhibition and Bleeding in Patients Undergoing Emergent Cardiac Surgery; clinicaltrials.gov NCT01468597).
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