Are Viscoelastic Tests Clinically Useful to Identify Platelet-Dependent Bleeding in High-Risk Cardiac Surgery Patients?

Abstract

BACKGROUND: Postoperative use of platelet function testing to rule out microvascular bleeding due to platelet dysfunction after cardiac surgery still lacks strong reference data and reliable cutoff values, yielding a clinically adequate sensitivity and specificity. The present study aims to investigate the performance of two different point-of-care viscoelastic devices and platelet aggregometry in expressing surgery-dependent platelet dysfunction and anticipating postoperative major bleeding in a cohort of high-risk patients. METHODS: Prospective cohort study of 50 adult patients who were on antiplatelet drugs discontinued for no more than 7 days (clopidogrel and prasugrel) or 5 days (ticagrelor) undergoing cardiac surgery with cardiopulmonary bypass (CPB). Coagulation and platelet function testing, including QUANTRA, ROTEM, and Multiplate, were assessed preoperatively and postoperatively. Chest drain blood loss was measured in the first 12 postoperative hours. Perioperative bleeding was assessed using a modified version of the Universal Definition of Perioperative Bleeding (UDPB) in cardiac surgery, modified to not consider anemia-correcting packed red cells transfusions in the absence of bleeding >600 mL/12 h. Major bleeding was identified as UDPB class II or higher. RESULTS: Multiplate adenosine diphosphate (ADPtest) was significantly (P = .001) reduced after CPB, whereas TRAPtest was not. The platelet component (PC) as extrapolated by ROTEM data (EXTEM MCF-FIBTEM MCF) was unchanged after CPB, while the A10 PC (PC at 10 minutes) was significantly (P = .001) reduced. The QUANTRA platelet contribution to clot stiffness (PCS) was significantly (P = .001) reduced, as well. At the ROC analysis for the predictive ability of the post-CPB platelet function testing, the best discrimination was obtained by the QUANTRA PCS, with an area under the curve (AUC) (95% confidence interval [CI]) of 0.80 (0.66-0.91), P = .001, followed by the ROTEM A10 PC with AUC (95% CI) of 0.75 (0.51-0.99), P = .004, and PC with AUC (95% CI) of 0.74 (0.50-0.99), P = .009. The Multiplate ADPtest had an AUC (95% CI) of 0.67 (0.42-0.91), and the TRAPtest had an AUC (95% CI) of 0.62 (0.37-0.86). The cutoff values identified were 13 hPa for the QUANTRA PCS, 40 mm for the ROTEM A10, and 48.5 mm for the ROTEM PC, with negative predictive values of 84%, 81%, and 86%, respectively, and positive predictive values of 55%, 53%, and 69%, respectively. CONCLUSIONS: QUANTRA PCS, ROTEM A10 PC, and Multiplate ADPtest showed a significant decrease after CPB, whereas ROTEM PC and Multiplate TRAPtest did not. Major bleeding was predicted with a moderate to good discrimination by the post-CPB viscoelastic tests (PCS, PC, and A10 PC). (Anesth Analg 2022;135:1198-206) KEY POINTS• Question: Are viscoelastic tests clinically useful to identify platelet-related bleeding in highrisk cardiac surgery patients? • Findings: Viscoelastic tests, namely QUANTRA PCS and ROTEM A10 PC and PC, are adequate in predicting major bleeding after cardiac surgery with a moderate deg...

In Response

“…We actually did this in the past, including about 500 patients preoperatively receiving MEA tests; actually, the results were partially disappointing, with AUCs not exceeding 0.71 for the adenosine-diphosphate test. Our recent study, 2 focused on a high-risk patient population, is confirmative of this finding.…”

“…We thank Terada et al 1 for their letter commenting on our study. 2 They raised interesting issues. We recognize that the topic of platelet function tests (PFTs) in cardiac surgery is highly controversial, and this is probably the reason why we disagree on the majority of the considerations raised by the authors.…”

Viscoelastic testing: Critical appraisal of new methodologies and current literature

“…8 The Quantra platelet contribution to clot strength (PCS) parameter decreases significantly over the course of cardiopulmonary bypass 27 and is significantly associated with major bleeding even after correction for platelet count. 58 The Quantra PCS and TEG 5000 CK MA both similarly predicted clinical need for transfusion of platelets (area under the curve 0.71 and 0.70, respectively) but both performed poorly at predicting the need for plasma transfusion. 59 In 200 adult cardiac surgical patients with ROTEM sigma collected immediately after heparin reversal, the mean sensitivity and specificity of FIBTEM A10 ≤ 8 mm for the identification of hypofibrinogenemia (<150 mg/dL) were 0.75 and 0.90, respectively, which are in a similar range to that reported in several previous studies using the ROTEM delta.…”

“…The Quantra platelet contribution to clot strength (PCS) parameter decreases significantly over the course of cardiopulmonary bypass 27 and is significantly associated with major bleeding even after correction for platelet count 58 . The Quantra PCS and TEG 5000 CK MA both similarly predicted clinical need for transfusion of platelets (area under the curve 0.71 and 0.70, respectively) but both performed poorly at predicting the need for plasma transfusion 59 …”

What Is the Best Monitoring Strategy for Platelet Function: Aggregability Count or Elasticity?

“…We read with interest a recently published article by Baryshnikova et al 1 regarding the utility of viscoelastic tests (VETs) and platelet aggregometry in high-risk cardiac surgery patients requiring cardiopulmonary bypass (CPB). Specifically, they sought to evaluate performance in identifying platelet dysfunction and in predicting major bleeding among patients who recently discontinued antiplatelet medications.…”