An overview of the potential sources of diagnostic errors in (classic) thromboelastography curve interpretation and preventive measures

Monitoring Hemostatic Function during Cardiac Surgery with Point-of-Care Viscoelastic Assays: A Narrative Review

Bleeding is a well-known and severe complication of cardiac surgery. Cardiopulmonary bypass, along with heparinization and hemodilution, is thought to affect all pathways of the hemostatic process, leading to excessive bleeding and worsened morbidity and mortality. The traditionally used standard laboratory tests (SLTs) were not designed for the surgical setting, have long turnaround times, and are poor predictors of bleeding. This review aims to give an overview of viscoelastic assays (VEAs), compare VEAs to conventional testing methods, and summarize the evidence for VEAs in cardiac surgery. A search of Medline via Pubmed, Scopus, and Embase yielded 2,868 papers, which we reviewed and summarized the key findings. VEAs such as rotational thromboelastometry and thromboelastography provide a quick turnaround, graphical, global impression of hemostasis in whole blood. VEAs allow for the analysis of specific contributors to the coagulation process and may facilitate cause-oriented hemostatic treatment and the development of treatment algorithms. VEAs have been found to have a high specificity and high negative predictive value for coagulopathic bleeding. Patients treated with VEA-based algorithms have been shown to have lower rates of bleeding, transfusion requirements, and exposure to allogeneic blood products. However, VEA-based algorithms have not demonstrated a mortality benefit and evidence for outcomes such as surgical re-exploration and hospital length of stay remains equivocal. In conclusion, VEAs have been shown to be comparable if not superior to SLTs in cardiac surgery. Further large-scale studies are needed to better evaluate the impact of VEAs on clinical outcomes.

Thromboelastography in Long-Term Antiplatelet Therapy for Patients Diagnosed with Benign Prostate Hyperplasia Undergoing Holmium Laser Enucleation of the Prostate: A Retrospective Study

Objective

To compare low- vs high-power HoLEP effects on coagulation in patients on antiplatelet (AP) therapy via thromboelastography (TEG).

Methods

210 patients was retrospectively analyzed and stratificated into three discrete groups, specifically: Group A (AP therapy, high-power HoLEP, n = 72); Group B (AP therapy, low-power HoLEP, n=73); Group C (no AP therapy, low-power HoLEP, n = 65). Baseline characteristics and coagulation profiles via TEG were compared. Univariate and multivariate analyses were conducted to identify independent risk factors associated with hematuria. Furthermore, parameters such as IPSS, Qmax, post-void residual volume V2 and PSA levels were recorded during 1year follow-up.

Results

No differences in terms of baseline characteristics across all groups. Significant differences were observed in the duration of enucleation, morcellation, bladder irrigation, post-operative catheterization, length of hospital stay and the extent of hemoglobin reduction (F = 54.06, 8.54, 6.68, 9.24, 17.06, 5.97, p < 0.05). No differences were noted in postoperative hematuria, urine retention, transfusion rates, and SUI (x1 2 = 1.082 ; x2 2 = 0.197,; x3 2 = 3.981;x4 2 = 0.816, p > 0.05). Univariate and multivariate analyses revealed that prostate volume emerged as an independent risk factor for hematuria (OR 1.080, 95% CI: 1.007-1.158, p = 0.031). Clinical outcomes including Qmax, IPSS, V2, and PSA demonstrated significant enhancement during 1 year follow-up.

Conclusion

Compared to HP-HoLEP, LP-HoLEP effectively reduces surgical and subsequent processing times, decreases hospital stay duration, and diminishes hemoglobin decline, offering a viable option without discontinuing AP therapy.

Kaolin activation of recalcified citrated whole blood in a point-of-care viscoelastic coagulation test

The viscoelastic coagulation monitor (VCM) is described as a point-of-care analyzer relying on activation of fresh whole blood (FWB) via contact between 2 glass plates. Kaolin is used as an activator in thromboelastography to reduce variability and shorten clotting times. The goal of this study was to compare VCM results from kaolin-activated, recalcified citrated samples with that from FWB. The VCM testing was performed using FWB and kaolin-activated, recalcified citrated samples. The VCM results were recorded for clot time (CT; seconds), clot formation time (CFT; seconds), alpha (degree), amplitude at 10 and 20 minutes (A10 and A20; VCM units), maximum clot firmness (MCF; VCM units), and lysis index (LI; %). Values were compared using a t-test or Wilcoxon-Mann-Whitney test, with a P-value < 0.05 considered significant. Variability between samples was calculated using Levene's test. The VCM kaolin activation resulted in significantly faster CT and CFT (P < 0.0001), higher alpha angle (P < 0.001), and higher A10 and A20 (P = 0.007, P = 0.015) compared to FWB. There was no difference in MCF, LI30, or LI45. There was no difference in variability identified. The addition of kaolin to recalcified citrated whole blood VCM samples results in more rapid clotting of FWB alone and could be considered for clinical use in dogs.

Application of thromboelastography in diagnosing normal pregnancies and pregnancies with complications

Background

This observational study aimed to compare the potential application of thromboelastography (TEG) in diagnosing women with normal pregnancy (NP) and women with threatened abortion (TA), missed abortion (MA), embryo arrest (EA), fetal death (FD), history of abnormal pregnancy (HAP), and antiphospholipid antibody syndrome (AA).

Methods

According to the relevant clinical criteria, patients were divided into groups, and their blood samples were subjected to TEG. Next, the parameters R, K, α‐angle, MA, LY‐30, G, and coagulation index (CI) were analyzed. Partial correlation analysis was used to analyze correlation between groups of data. LSD‐t test and Dunnett's T3 test were used to analyze continuous variables. Ordinal categorical variables were compared using ordinal logistic regression analysis and estimate odds ratio of risk factors. A receiver operating characteristic (ROC) curve was constructed to detect the ability of TEG to recognize various parameters, and areas under the curve were compared using Delong's test for diagnosing pregnancy‐related diseases.

Results

MA had a negative effect on the MA parameter in TEG; EA had a negative effect on the MA and G parameters; HAP had a negative effect on the CI parameter and a positive effect on the R parameter; AA had a negative effect on the CI parameter. Compared with that of the NP group, the G of the EA (p = 0.014) group and the CI of the TA (p = 0.036) MA (p = 0.08) EA (p = 0.026) HAP (p = 0.000004) and AA (p = 0.002) groups were reduced. In the ordinal logistic regression analysis, compared with that of the NP group, the high R value of the HAP group accounted for more than that of the NP group (OR = 48.76, p = 0.001); the high K value of the AA group accounted for more than that of the NP group (OR = 17.00, p = 0.023); the angle value distributions of the TA and AA groups were different from that of the NP group (OR = 3.30, p = 0.039; OR = 0.14, p = 0.029); the low MA value of the MA, EA, and HAP groups accounted for more than that of the NP group (OR = 0.16, p = 0.03; OR = 0.26, p = 0.005; OR = 0.11, p = 0.008); and the low CI value of the HAP group accounted for more than that of the NP group (OR = 0.09, p = 0.005). In the ROC analysis, there were no significant differences in the TEG parameters of pregnant women belonging to the NP and TA, NP and MA, NP and EA, NP and FD, NP and HAP, and NP and AA groups (p > 0.05).

Perioperative Coagulation Monitoring

The main goal of perioperative coagulation monitoring is to improve safety of patients undergoing surgical procedures. Various conditions can affect the coagulation system during surgery and bleeding. The value of traditional standard coagulation tests is limited in detecting hemostatic dysfunctions and they are particularly ineffective in diagnosing hyperfibrinolysis. This article reports on key issues and pathophysiologic changes that affect the hemostatic system in the perioperative setting. Values of preoperative coagulation tests are discussed and the basic principles for point-of-care coagulation devices, including platelet analyzers and their clinical use, are evaluated.