Near-Patient Thrombin Generation in Patients Undergoing Elective Cardiac Surgery

Abstract

Background: Measuring thrombin generation (TG) in plasma increasingly gained attention as a diagnostic tool in the field of thrombosis and hemostasis. To include the contribution of all blood cells, recently, the whole blood TG method was developed. Methods: We changed the calculation method of the standard calibrated automated thrombography (CAT) to a method only taking into account the data until the peak of TG, thereby considerably reducing the time from blood draw to result. By redesigning the method, the blood volume per test was reduced to 15 μL. Results: For all TG parameters, the interassay variation proved to be below 15%. The interindividual variation of all parameters was comparable to the CAT method. Thirty-three patients undergoing cardiothoracic surgery were included to investigate whether our assay correlates with postoperative blood loss. On dividing patients into severe and mild bleeders, significant differences between both groups were found for the peak endogenous thrombin potential (peakETP) and peak values determined by our near-patient device. Importantly, patients with a peakETP below the median experienced significantly more blood loss compared to those with a peakETP above the median. A similar division based on the peak as well as the body mass index of the patient yielded similar significant differences. A combination of the peakETP, the body mass index, and the lag time even resulted in a better predictor of blood loss compared to each parameter separately. Conclusions: Our adapted whole blood TG assay can be used near patients and is indicative for the amount of blood loss post cardiothoracic surgery.

Whole blood thrombin generation profiles of patients with cirrhosis explored with a near patient assay

“…WB‐TG was measured on a previously described miniaturized TG device and a newly modified microfluidic chip. The previous chip, which was made from methyl methacrylate‐acrylonitrile‐butadienestyrene (MABS), suffered from occasional fluid leakage .…”

“…WB‐TG was measured on a previously described miniaturized TG device and a newly modified microfluidic chip. The previous chip, which was made from methyl methacrylate‐acrylonitrile‐butadienestyrene (MABS), suffered from occasional fluid leakage . We adopted a new design for the chip, which consisted of two pieces of polydimethylsiloxane (PDMS) with a porous matrix disc of 5 mm in diameter and 190 µm in thickness (grade 589/1; Whatman) in between.…”

“…The previous chip, which was made from methyl methacrylate-acrylonitrile-butadienestyrene (MABS), suffered from occasional fluid leakage. 19 We adopted a new design for the chip, which consisted of two pieces of polydimethylsiloxane (PDMS) with a porous matrix disc of 5 mm in diameter and 190 µm in thickness (grade 589/1; Whatman) in between. The two PDMS parts were prepared in house by mixing 10 parts of polymer with 1 part of curing agent (Sylgard 184, Dow Corning) and then solidified in an aluminum mold at 100°C for 90 minutes.…”

“…19 This assay was shown to be predictive of postoperative blood loss in patients undergoing elective cardiac surgery. 19 The short turnaround time and compact size of the near patient WB-TG assay system allows possible deployment outside a specialized laboratory environment. In this study, for the first time, we studied WB-TG profiles of a cohort of patients with cirrhosis by using the near patient assay.…”

“…We have previously developed a near patient WB‐TG assay by using a miniaturized TG device and a microfluidic chip . This assay was shown to be predictive of postoperative blood loss in patients undergoing elective cardiac surgery . The short turnaround time and compact size of the near patient WB‐TG assay system allows possible deployment outside a specialized laboratory environment.…”