The role of platelet function analyzer-200 in predicting perioperative bleeding risk

Linking triphenylphosphonium cation to a bicyclic hydroquinone improves their antiplatelet effect via the regulation of mitochondrial function

Platelets are the critical target for preventing and treating pathological thrombus formation. However, despite current antiplatelet therapy, cardiovascular mortality remains high, and cardiovascular events continue in prescribed patients. In this study, first results were obtained with ortho-carbonyl hydroquinones as antiplatelet agents; we found that linking triphenylphosphonium cation to a bicyclic ortho-carbonyl hydroquinone moiety by a short alkyl chain significantly improved their antiplatelet effect by affecting the mitochondrial functioning. The mechanism of action involves uncoupling OXPHOS, which leads to an increase in mitochondrial ROS production and a decrease in the mitochondrial membrane potential and OCR. This alteration disrupts the energy production by mitochondrial function necessary for the platelet activation process. These effects are responsive to the complete structure of the compounds and not to isolated parts of the compounds tested. The results obtained in this research can be used as the basis for developing new antiplatelet agents that target mitochondria.

Platelet function analyzer-200 closure curve analysis and assessment of flow-obstructed samples

BACKGROUND

The Platelet function analyzer-200 can determine the effect of clopidogrel in cats. Flow obstruction is an error that causes uninterpretable results. Closure curves and parameters initial flow rate (IF) and total volume (TV) are displayed by the PFA-200 and may allow interpretation of results in cases of flow obstruction. The primary hemostasis components (PHC) are calculated values that normalize these parameters.

OBJECTIVES

To determine if closure curves and research parameters allow detecting the effect of clopidogrel in cases of flow obstruction.

METHODS

A review of closure curves identified those with flow obstruction and paired analysis that did not. Non-flow-obstructed curves were used to categorize curves with respect to clopidogrel effects. IF, TV, PHC(1), and PHC(2) were evaluated to determine if these could be used to categorize if a sample exhibited the effects of clopidogrel. Curves were visually analyzed, and characteristics identified that were more common with or without the effect of clopidogrel. Visual analysis of curves was performed by blinded observers to determine if a visual analysis was able to predict the effect of clopidogrel.

RESULTS

Analysis of parameters was able to predict closure or non-closure in flow-obstructed curves. TV, PHC(1), and PHC(2) had area under the curve of the receiver operating characteristics of 0.79, 0.79, and 0.87. Visual curve analysis was unable to predict closure, with an average accuracy of only 55%, among three reviewers. Agreement between reviewers was poor (Fleiss' Kappa 0.06).

CONCLUSIONS

Visual curve analysis was unable to determine the effect of clopidogrel in flow-obstructed samples. Numerical parameters were able to detect the effect of clopidogrel with a high degree of accuracy in flow-obstructed samples.

Investigation of Platelet Function Analyzer 200 platelet function measurements in healthy cats and cats receiving clopidogrel

The Platelet Function Analyzer 200 (PFA-200; Siemens) is an in vitro substitute for in vivo bleeding time that is designed to investigate platelet function in a more physiologic manner than traditional aggregometry. The analyzer reports a closure time (CT) as a marker of platelet function, and may also report the calculated platelet function measurement primary hemostasis components, PHC1 and PHC2. These incorporate the measured total volume (TV) of blood aspirated and the initial flow rate (IF). We determined, for the COL/ADP and P2Y cartridges, the median total volume (TVmedian), and RIs for CT, IF, TV, PHC1, and PHC2, and investigated the sensitivity and specificity of those parameters at the determined interpretation thresholds in determination of the clopidogrel effect. Healthy client-owned cats were recruited prospectively to determine RIs for CT, IF, TV, PHC1, and PHC2. Healthy blood-donor cats and cats on clopidogrel therapy were included retrospectively to determine test performance. In 20 healthy cats, RIs for COL/ADP were CT (19.5-87.2 s), IF (199-278 µL/min), TV (199-332 µL), PHC1 (94-106%), and PHC2 (52-148%); and for P2Y, CT (4.2-94.3 s), IF (112-208 µL/min), TV (151-294 µL), PHC1 (35-178%), and PHC2 (90-109%). CVs were calculated for all of these values. Specificity for detection of the clopidogrel effect was calculated from a group of healthy blood donors, and sensitivity for detection of the clopidogrel effect from a group of cats with known clopidogrel effect. Sensitivity and specificity were, for COL/ADP: CT (83.3%, 66.6%), IF (41.4%, 83.3%), TV (83.3%, 100%), PHC1 (100%, 100%) and PHC2 (100%, 83.3%); and for P2Y: CT (100%, 94.4%), IF (30%, 44.4%), TV (100%, 94.4%), PHC1 (100%, 100%), and PHC2 (100%, 97.7%). These PFA-200 values may be beneficial in the determination of platelet function in cats.

Coagulation Dysfunction in Patients with Liver Cirrhosis and Splenomegaly and Its Countermeasures: A Retrospective Study of 1522 Patients

Objective

Patients with cirrhosis and splenomegaly often have coagulation dysfunction which affects treatment and prognosis. This study explores the status, grading, and treatment strategies of coagulation dysfunction in patients with liver cirrhosis and splenomegaly.

Methods

A retrospective cohort study was conducted on the clinical data on consecutive patients with cirrhosis and splenomegaly treated at Hainan General Hospital, China, from January 2000 to December 2020. Starting research in January 2022.

Results

Among 1522 patients included into this study, 297 (19.5%) patients had normal results in all five coagulation tests (prothrombin time, prothrombin activity, activated partial thromboplastin time, thrombin time, and fibrinogen), and 1225 (80.5%) had coagulation dysfunction in at least one of these tests. There were significant differences (P < 0.05) in treatment efficacy on these patients for three of these five coagulation tests, with the exception of prothrombin activity and thrombin time. When coagulation dysfunction was classified into grades I, II, and III based on scores from the three significant coagulation tests, prothrombin time, activated partial thromboplastin time, and fibrinogen, significant differences in surgical outcomes were found among the three grades of coagulation dysfunction and between grades I and III (P < 0.05). The operative mortality rate in patients with grade III in treating liver cancer, portal hypersplenism, and/or splenomegaly was 6.5%. There was no significant difference between patients with grades I and II (P > 0.05).

Conclusions

Approximately, 80% of patients with liver cirrhosis and splenomegaly had coagulation dysfunction. Surgery is feasible for grade I and II patients. For grade III patients, nonsurgical treatment should be given first, and surgery should only be considered when the coagulation function returns to normal or near-normal levels after treatment. This trial is registered with MR-46-22-009299.

Comparison of Clopidogrel, Prasugrel and Ticagrelor Response of Patients by PFA-100-Innovance Test Results

Devices such as stents and flow diverters require the use of safe and fast antiplatelet therapy. We aimed to compare the responses to clopidogrel, prasugrel, and ticagrelor by assessing the Platelet Function Analysis (PFA-100)-Innovance test results of patients undergoing endovascular stenting to determine their resistance rates. Sixty-one women and 55 men, aged 18-87 years, were included in this study. Patients were divided into three groups: clopidogrel treatment, prasugrel treatment, and ticagrelor treatment. The systemic diseases of the patients, especially hypertension and diabetes, were recorded. The test results were evaluated according to the results for the collagen/epinephrine (COL-EPI), collagen/adenosine (COL-ADP), and P2Y results. The PFA-100-Innovance results for COL-EPI and P2Y were significantly higher for patients treated with prasugrel and ticagrelor compared with patients treated with clopidogrel (COL-EPI, p = 0.001; P2Y, p = 0.001). Clopidogrel resistance was identified in 31 patients (26.7%), and prasugrel resistance was identified in 4 patients (3.4%). Ticagrelor resistance was not detected. Therefore, 30.1% of patients were classified as drug-resistant. Perioperative bleeding was not detected in any patient. Hypertension was the most common disease recorded for patients being treated for cerebral aneurysm, and diabetes was the most common disease recorded for patients who underwent peripheral artery stenting (p = 0.002). Potent antiplatelet agents, such as prasugrel and ticagrelor, have a low rate of resistance but are associated with an increased bleeding risk. Thus, the choice of a suitable drug during the treatment window remains a critical factor when determining treatment strategies.

Gastrointestinal bleeding during the transcatheter aortic valve replacement perioperative period: A Review

With the aging of the population, the incidence of senile degenerative valvular heart disease is expected to increase. Transcatheter aortic valve replacement (TAVR) has been used for patients at lower surgical risk with symptomatic severe aortic valve stenosis. Because of the improvements in TAVR technology and increasing experience of the operators, TAVR is regarded as a safe and feasible procedure. Bleeding events during the TAVR perioperative period, especially gastrointestinal (GI) bleeding, have been proven to be related to the long-term prognosis and mortality. Elderly patients with valvular heart disease are susceptible to GI bleeding because of their use of antithrombotic drugs, physical damage of coagulation factors, and GI angiodysplasia. Frequent GI bleeding and low levels of preoperative hemoglobin increase the risk of TAVR, especially for elderly patients. Because of these risks, which are easily overlooked, we should focus more attention on the perioperative management of TAVR. Reasonable screening tools, including blood examinations, risk evaluation scales, and endoscopy, are beneficial to the prevention of complications that can occur during the perioperative period. Additionally, medical therapy can safely help patients at high-risk for bleeding patients throughout the perioperative period. This study aimed to characterize the pathology of TAVR patients and discuss treatment strategies for GI bleeding during the perioperative period.

Is the platelet function test effective in predicting blood loss in patients undergoing hepatic resection?

Purpose

The platelet function analyzer (PFA)-100/200 is widely used to assess platelet function. However, its role in predicting the perioperative risk of bleeding in patients undergoing liver resection remains controversial. Therefore, we aimed to ascertain whether the platelet function test could be useful in predicting bleeding risk in patients undergoing hepatic surgery.

Methods

The study participants were patients who underwent hepatectomy for hepatocellular carcinoma at our hospital over a period of 10 years from January 1, 2010 to May 31, 2020. PFA-200 values of these patients were divided into 2 groups; normal (n = 333) and prolonged (n = 39).

Results

There were no significant differences regarding the volumes of calculated blood loss during surgery between the normal and prolonged PFA groups (879.55 ± 1,046.50 mL vs. 819.74 ± 912.64 mL, respectively; P = 0.733); intraoperative RBC transfusion (0.52 ± 2.02 units vs. 0.26 ± 1.02 units, P = 0.419) and postoperative RBC transfusion (0.24 ± 1.17 units vs. 0.46 ± 1.97 units, P = 0.306) were similar between the 2 groups, respectively. Multivariate analysis revealed no association between PFA closure time and calculated blood loss (hazard ratio, 1.06; P = 0.881). Moreover, there was no association between PFA closure time and preoperative laboratory results or assessment of tool-related liver function in multivariate analysis.

Conclusion

There was no correlation between the amount of blood loss and platelet function in patients who underwent liver resection. In patients undergoing liver resection who are not managed on antiplatelet agents or do not have chronic kidney disease, the use of routine PFA is not recommended.