Utility of Sonoclot in Prediction of Postoperative Bleeding in Pediatric Patients Undergoing Cardiac Surgery for Congenital Cyanotic Heart Disease: A Prospective Observational Study

Glass bead-activated clotting time (gb-ACT) for monitoring the anticoagulation effects in elderly patients with high risk of venous thromboembolism (VTE)

BACKGROUND

To find a new bedside method to monitor the anticoagulation effects of low-molecular-weight heparins (LMWHs) in patients with a high risk of venous thromboembolism (VTE).

RESEARCH DESIGN AND METHODS

A total of 32 hospitalized patients (aged ≥60 years) who were at high risk of VTE were assigned to receive subcutaneous LMWH for 5 to 14 days. Plasma anti-factor Xa (anti-Xa) activity was conducted by a chromogenic method, and the glass bead-activated whole blood clotting time (gb-ACT) value was obtained by a Sonoclot Analyzer.

RESULTS

A correlation between the gb-ACT values and the anti-Xa levels was suggested (R = 0.447, p = 0.002), and it was stronger in the older group aged 80 years above (R = 0.467, p = 0.008) and in the group of patients with an eGFR of 30 ~ 60 mL/min (R = 0.565, p = 0.005). The area under the curve (AUC) for gb-ACT by receiver operating characteristic (ROC) curve evaluation was 0.725 (p = 0.011), and the gb-ACT >282.5s provided a sensitivity of 60% and specificity of 74% for anti-Xa >0.800 IU/ml.

CONCLUSIONS

The gb-ACT values detected by a Sonoclot Analyzer could act as a novel bedside method in the monitoring of LMWH anticoagulation.

Model construction and application for predicting pre-eclampsia by Sonoclot coagulation analyzer

Maternal age has significantly increased among Chinese women, thereby posing risk of pregnancy-related complications. Preeclampsia is a leading cause of maternal and perinatal morbidity and mortality, and coagulation analysis in conjunction with clinical signs and symptoms are generally used for its diagnosis with limited efficacy. Sonoclot coagulation analyzer is effective in assessing coagulation function used during cerebral surgery and cardiovascular surgery. However, its use has not been explored in preeclampsia. Here, we investigated the potential use of Sonoclot in diagnosing preeclampsia in obstetrics cases. Subjects meeting the screening criteria were divided either into a test group or a control group, according to whether they were preeclamptic or not. We recorded the Sonoclot-derived coagulation and the routine coagulation parameters including platelet function (PF), activated clotting time (ACT) and clot rate (CR), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (FIB), and platelet count. Regression analysis was done on the relevant parameters to assess the feasibility of Sonoclot analyzer in preeclampsia diagnosis. In parallel, changes in preeclampsia lncRNAs was also evaluated. Significant differences were recorded in PT and ACT between the two groups. In the monovariant logistic regression, PT and ACT appeared to be reliable predictor variables. In the multinomial logistic regression, a total of five regression steps were performed with decreasing AIC values. The K-fold cross validation resulted in an accuracy rate (ACC) of 77.5%, a false positive rate of 16.4%, and a false negative rate of 33.2%. lncRNAs ANRIL and HOXD-AS1 were found deregulated. Our findings indicate that Sonoclot may be useful for diagnosis of preeclampsia in obstetrics.

Platelet Function Testing Using Sonoclot and TEG6s as a Platelet Transfusion Prediction Tool in Open Heart Surgery

Introduction The point-of-care test (POCT) is useful for blood coagulation management during cardiovascular surgery. Although thromboelastography (TEG6s) has been reported to have targeted benefits for blood transfusion in cardiac surgery, Sonoclot analysis has not yet been fully validated. In this study, we evaluated the accuracy of Sonoclot, especially platelet function (PF) as a platelet concentrate (PC) transfusion parameter, compared to TEG6s in cardiovascular surgery. Methods This single-center, prospective, randomised trial was conducted at a university hospital. Forty-two adult patients who underwent elective cardiac surgery requiring cardiopulmonary bypass were included in this study between 2017 and 2021. The participants were randomly assigned to the Sonoclot (S) or Sonoclot and TEG6s (ST) groups. The amount of intraoperative PC was determined according to the POCT parameter values at the time of protamine administration. In addition, we investigated the correlation between PF parameters of POCT and platelet count at the end of surgery. Results There was no statistically significant difference in the intraoperative PC volume between the two groups. The Sonoclot PF parameter, PF, was moderately correlated with platelet count at the end of surgery (r=0.5449, p=0.009), and the TEG6s PF parameter showed a strong correlation with platelet count at the end of surgery (r=0.7744, p<0.001). Conclusion There was no statistically significant difference in platelet transfusion volume between the Sonoclot and TEG6s in this study. The correlation between the PF of the Sonoclot and platelet count was moderate. This study suggests that PF of Sonoclot may be a potentiating indicator of PF.

Comparison of the predictive value of thromboelastography and Sonoclot analysis for postoperative bleeding in children undergoing corrective surgery for cyanotic congenital heart disease

Background

The aim of the study was to compare the predictive value of Sonoclot analysis and thromboelastography (TEG) for postoperative bleeding in children younger than 12 years coming for cardiac surgery for congenital cyanotic heart disease.

Methods

This is a prospective, observational study carried out in a single tertiary care military hospital. Ninety patients of the paediatric age group undergoing bypass cardiac surgery for correction of congenital cyanotic heart defect were included in the study. Laboratory-derived values to assess coagulation status (prothrombin time, international normalisation ratio, activated partial thromboplastin time) and point-of-care Sonoclot- and TEG-derived parameters were noted at the start of surgery and postoperatively in all patients. Bleeders were predefined on the basis of chest tube drainage.

Results

The incidence of bleeders was 42.2% (38/90 patients), whereas 57.8% (52/90 patients) were non-bleeders. The postoperative R value and preoperative gbPF test were predictive for postoperative bleeders on multivariate analysis. Postoperative gbPF had the highest area under the curve (0.72), with a cut-off value of 1.75, and gbPF had 82% sensitivity and 71% specificity in predicting significant postoperative bleeding in paediatric cyanotic congenital heart surgeries. Transfusion requirements and mechanical ventilation duration were higher in bleeders; however; length of intensive care unit stay, incidence of sepsis and mortality were similar in both the groups.

Conclusion

Bleeding in patients undergoing corrective surgery for cyanotic congenital heart disease could be predicted by the preoperative gbPF and postoperative R value. Among these, preoperative gbPF has the maximum predictive value.

Utility of the Sonoclot analyzer to assess hyperfibrinolysis in dogs

BACKGROUND

Coagulation abnormalities, including hyperfibrinolysis, have been documented in sick veterinary patients. Viscoelastic tests, including the Sonoclot Coagulation and Platelet Function Analyzer, are useful in detecting hyperfibrinolysis. Tissue plasminogen activator (tPA) assays have been used to quantify fibrinolysis using thromboelastography.

OBJECTIVES

We aimed to document and evaluate changes in the whole blood of healthy dogs exposed to in vitro tPA at varying concentrations using the Sonoclot analyzer.

METHODS

Ten milliliters of blood was collected from healthy adult dogs. Sonoclot tests were run in duplicate and included a control sample and five tPA concentrations: 50, 75, 100, 150, and 200 IU/mL of blood.

RESULTS

Eleven dogs were enrolled in the study. Based on standard Sonoclot Signature changes, a numeric value fibrinolysis time (FTi) was derived to aid in the quantification of hyperfibrinolysis. Activated clotting time and clot rate Sonoclot values were not significantly affected by any tPA concentration. There was a significant decrease in platelet function (PF) at tPA concentrations equal to and above 75 IU/mL on channel 1 and tPA concentrations of 150 IU/mL and higher on channel 2. There was a progressive decrease in FTi at increasing tPA concentrations.

CONCLUSIONS

The Sonoclot analyzer can be used to evaluate hyperfibrinolysis. Predictable changes were seen in the Sonoclot Signature and a decrease in PF and FTi was found with increasing tPA concentrations. The Sonoclot assay with a tPA concentration of 100 IU/mL is suggested a baseline measure of hyperfibrinolysis and has a resultant median FTi of 42 minutes, which is a practical time for clinical applications.

Viscoelastic test-based bleeding risk score reliably predicts coagulopathic bleeding in decompensated cirrhosis and ACLF patients

BACKGROUND AND AIMS

Coagulopathic bleeding risk prediction is challenging in decompensated cirrhosis (DC) by conventional assays. Viscoelastic tests (VETs) are likely to be more useful for assessing coagulation status in these patients. We investigated whether the VET (Sonoclot) parameters with fibrinogen could predict coagulopathic bleeding in these patients.

PATIENTS AND METHODS

Coagulation parameters studied in 874 patients [124 compensated cirrhosis (CC), 521 DC, and 229 acute-on-chronic liver failure (ACLF)] and 190 controls. DC patients were enrolled in derivation (n = 266) and validation (n =  255) cohorts. Sonoclot variables [activated clotting time (ACT), clot rate (CR), platelet function (PF), time to peak (TP) and peak amplitude (PA)] and fibrinogen levels were measured. Coagulopathic bleeding was recorded along with 1-year survival.

RESULTS

DC patients had prolonged ACT (p < 0.001), depressed CR (p = 0.059), reduced PF (p = 0.09), longer TP (p < 0.001) and smaller PA (p < 0.001), compared to CC and controls (p < 0.001 each). In derivation cohort, 32.3% patients had coagulopathic bleeding. Cox regression analysis of derivation cohort revealed; ACT > 190 s, PF < 1.25 and fibrinogen < 1.2 g/l could predict coagulopathic bleeding and were used to develop a bleeding risk score. In validation cohort; this score was comparable, correlated to real events, and had similar bleed free events with time. The score was also useful in predicting bleed in ACLF patients. In DC patients, 1-year mortality was higher those who bled and received transfusions.

CONCLUSION

Viscoelasticity-based bleeding risk score using ACT, PF and fibrinogen, predicts coagulopathic bleeding in DC patients and should be useful in rationalizing transfusion of blood products. We designed a viscoelastic test-based bleeding risk score which is useful in advanced liver disease to predict the coagulation-related bleeding. This figure shows the lower bleeding-free events in advanced cirrhosis with each incremental bleeding risk score.

Efficacy of Resuscitative Transfusion With Hemoglobin Vesicles in the Treatment of Massive Hemorrhage in Rabbits With Thrombocytopenic Coagulopathy and Its Effect on Hemostasis by Platelet Transfusion

INTRODUCTION

We have developed hemoglobin vesicles (HbVs) as a substitute for red blood cells (RBCs). We investigated the efficacy of HbV transfusion in the treatment of massive hemorrhage in rabbits in the setting of thrombocytopenic coagulopathy, focusing on the efficacy of hemostasis by subsequent platelet transfusion.

METHODS

Thrombocytopenic coagulopathy was induced in rabbits by repeated blood withdrawal and isovolemic retransfusion of autologous RBC (platelet counts <45,000/μL). A penetrating liver injury was then made. For 30 min, bleeding volume was measured every 10 min, after which subjects were transfused with an equivalent volume of stored RBC, HbV, or platelet poor plasma (PPP) to compensate for blood loss, simulating initial prehospital resuscitation. Thereafter, we transfused platelet rich plasma (PRP) to stop bleeding, which simulated inhospital resuscitation.

RESULTS

During the initial resuscitation, the HbV group was similar to the RBC group (but not the PPP group) in their hemodynamics and tissue circulation/oxygenation as assessed by plasma lactate levels. All rabbits showed similar bleeding volumes (20-30 mL) in this period. HbV-transfused rabbits sustained hemoglobin levels, but showed lower hematocrit levels compared with RBC-transfused rabbits. Subsequent PRP transfusion effectively stopped bleeding in all RBC-transfused rabbits (6/6) and most HbV-transfused rabbits (7/8) but not PPP-transfused rabbits (2/8). In addition, 83% of RBC-transfused rabbits and 75% of HbV-transfused rabbits survived for 24 h, although no PPP-transfused rabbits survived. HbV transfusion did not scavenge nitric oxide in rabbits.

CONCLUSIONS

HbV transfusion effectively rescued rabbits from severe hemorrhage with coagulopathy, without disturbing hemostasis after the platelet transfusion. HbV transfusion may be practical and useful in prehospital resuscitation.

Noteworthy Literature published in 2017 for Congenital Cardiac Anesthesiologists

This review focuses on the literature published during the 13 months from December 2016 to December 2017 that is of interest to anesthesiologists taking care of children and adults with congenital heart disease. Five themes are addressed during this time period and 100 peer-reviewed articles are discussed.