This study will evaluate the performance of the Quantra System comprised of the Quantra Hemostasis Analyzer with the QPlus Cartridge in patients taking anitplatelet medication that are scheduled to undergo cardiac surgery.

The Quantra System is a fully integrated and automated in vitro diagnostic device which uses SEER Sonorheometry, an ultrasound-based technology, to characterize the viscoelastic properties of a whole blood sample during coagulation. The Quantra QPlus Cartridge was developed to monitor hemostasis during major surgical procedures in adult patients. The cartridge consists of four independent channels each containing different sets of reagents, which provide four measurements performed in parallel yielding six parameters that depict the functional status of a patient's coagulation system.

This single-site, prospective, observational study will evaluate the performance of the Quantra System as compared to standard coagulation tests and comparable measures determined using TEG in patients taking antiplatelet medication that are scheduled to undergo cardiac surgery.

Inclusion Criteria:

• Subject is scheduled for elective cardiac surgery utilizing cardiopulmonary bypass, including the placement of a ventricular assist device
• Subject was identified as taking antiplatelet medication, specifically a P2Y12 inhibitor such that a TEG Platelet Mapping test is prescribed prior to surgery to assess possible platelet inhibition
• Subject is ≥ 18 years
• Subject is willing to participate and he/she has signed a consent form

Exclusion Criteria:

• Subject is younger that 18 years
• Subject is unable to provide written informed consent
• Subject is incarcerated at the time of the study
• Subject is pregnant
• Subject is currently enrolled in a distinct study that might confound the results of the proposed study
• Subject is affected by a condition that, in the opinion of the clinical team, may pose additional risks.

Potential study participants will be adult (≥ 18 years) subjects who are taking antiplatelet medication and who are scheduled for elective cardiac surgery utilizing cardiopulmonary bypass, including the placement of a ventricular assist device.