Original Article

Platelet Mapping by Thromboelastography and Whole Blood Aggregometry in Adult Patients Supported by Mechanical Circulatory Support Device on Aspirin Therapy

^* Department of Pathology, Cedars Sinai Medical Center, Los Angeles, California; and
^† Cedars Sinai Comprehensive Transplant Center, Cedars Sinai Medical Center, Los Angeles, California

Address correspondence to: Oksana Volod, MD, Department of Pathology and Laboratory Medicine, Cedars Sinai Medical Center, Los Angeles, CA 90048. E-mail: oksana.volod@cshs.org

Received: 28 September 2019
Accepted: 24 February 2020

Abstract

Patients on mechanical circulatory support (MCS) devices are placed on aspirin and may require platelet function testing (PFT) to monitor the adequacy of therapy. Routine laboratory PFT is performed using whole blood aggregation (WBA) which typically has a long turnaround time (4–5 hours) and may not be readily available. By contrast, platelet mapping by thromboelastography (TPM) can provide results within 45 minutes. The objective of this study was to compare the results of TPM with WBA. We compared platelet mapping maximal amplitude (MA) by TPM with that of arachidonic acid (AA) to WBA with AA by impedance. We analyzed paired samples where both TPM and WBA were available. Of 45 paired samples, 34 were from 29 MCS patients and 11 were from non-MCS patients. When applying institutional interpretation guidelines with an MA_Activator cutoff of ≤40 mm, WBA_AA vs TPM MA_AA in non-MCS and MCS patients correlated well with an accuracy of 100 and 94.4%, respectively. MA_Activator >40 had poor correlation with an accuracy of 37.5%. Irrespective of MA_Activator value, TPM AA inhibition expressed in percent of inhibition had poor accuracy. When used with proper guidelines for interpretation, specifically when MA_Activator ≤ 40 mm, TPM is a suitable and reliable test to use for MCS patients on aspirin.