Fibrinolysis resistance after liver transplant as a predictor of early infection.

BACKGROUND: Infection is a leading cause of morbidity in liver transplant (LT). Considering that the fibrinolytic system is altered in sepsis, we investigated the relationship between fibrinolysis resistance (FR) and post-transplant infection. METHODS: Fibrinolysis was quantified using thrombelastography (TEG) with the addition of tPA to quantify FR. FR was defined as LY30 = 0% and stratified as transient if present on POD1 or POD5 (tFR), persistent (pFR) if present on both, or no FR (nFR) if absent. RESULTS: 180 LT recipients were prospectively enrolled. 52 (29%) recipients developed infection. 72 had tFR; 37 had pFR; and 71 had nFR. Recipients with pFR had significantly greater incidence of infections (51% vs. 26% tFR vs. 20% nFR, p = 0.002). pFR was independently associated with increased odds of post-transplant infection (adjusted OR 3.39, p = 0.009). CONCLUSIONS: Persistent fibrinolysis resistance is associated with increased risk of post-transplant infection.

Does the mechanism matter? Comparing thrombelastography between blunt and penetrating pediatric trauma patients.

BACKGROUND/PURPOSE: The utility of thrombelastography (TEG) in pediatric trauma remains unknown, and differences in coagulopathy between blunt and penetrating mechanisms are not established. We aimed to compare TEG patterns in pediatric trauma patients with blunt solid organ injuries (BSOI) and penetrating injuries to determine the role of mechanism in coagulopathy. METHODS: Highest-level pediatric trauma activations with BSOI or penetrating injuries and admission TEG at two pediatric trauma centers were included. TEG abnormalities were defined by each institution's normative values and compared separately by injury mechanism and evidence of shock (elevated SIPA) using Kruskal-Wallis or Fisher's exact tests. RESULTS: Of 118 patients included, 64 had BSOI and 54 had penetrating injuries. There were no significant differences in TEG abnormalities between the BSOI and penetrating injury groups. Patients with shock were more likely to have decreased alpha-angles (30.9% vs. 8.0%, p = 0.01) and decreased maximum amplitude (MA) (44.1% vs. 8.0%, p < 0.001) compared to those without shock, regardless of mechanism of injury. CONCLUSIONS: TEG abnormalities were not significantly different between the BSOI and penetrating groups, but there were significant differences in alpha-angle and MA in those with shock, independent of mechanism. Hemodynamic status, rather than mechanism of injury, may be more predictive of coagulopathy in pediatric trauma patients. LEVEL OF EVIDENCE/STUDY TYPE: Level III, retrospective.

Pneumatic tube transport of blood samples affects global hemostasis and platelet function assays.

INTRODUCTION: Pneumatic tube systems (PTS) are frequently used for rapid and cost-effective transportation of blood samples to the clinical laboratory. The impact of PTS transport on platelet function measured by the Multiplate system and global hemostasis measured by the TEG 5000 was evaluated. METHODS: Paired samples from healthy adult individuals were obtained at two study sites: Rigshospitalet (RH) and Nordsjaellands Hospital (NOH). One sample was transported by PTS and one manually (non-PTS). Platelet function was assessed by platelet aggregation (Multiplate) and global hemostasis was assessed by a variety of thrombelastography (TEG) assays. Multiplate (n = 39) and TEG (n = 32) analysis was performed at site RH, and Multiplate (n = 28) analysis was performed at site NOH. RESULTS: A significant higher agonist-induced platelet aggregation was found for PTS samples compared to manual transport at site NOH (P < .02, all agonists). No significant difference was found at site RH (P > .05, all agonists). For Kaolin TEG, samples transported by PTS showed a significant lower R-time and higher Angle (P < .001). No significant differences in MA and LY30 was found (P > .05). ACT of RapidTEG was significantly reduced (P = .001) and MA of Functional Fibrinogen TEG was significantly increased (P < .001) after PTS transport. No significant impact of PTS was observed for TEG assays with heparinase (P > .05). CONCLUSIONS: Depending on the type of PTS, transportation by PTS affected platelet aggregation measured by Multiplate. Furthermore, PTS alters TEG parameters possibly reflecting coagulation factors. Clinical laboratories should evaluate the effect of the local PTS on Multiplate and TEG results.

Platelet-fibrin clot strength measured by thromboelastography could predict hypercoagulability and antiplatelet effects in patients after percutaneous coronary intervention.

BACKGROUND: It has been estimated that nearly one-fifth post-percutaneous coronary intervention (PCI) patients treated with clopidogrel continued to have recurrent thrombotic events, which implied the limitation of "one-size-fits all" strategy for antiplatelet therapy. METHODS: From July 2017 to April 2019, patients with acute coronary syndrome [ACS, including unstable angina (UA), non-ST segment elevation myocardial infraction (NSTEMI), and ST segment elevation myocardial infraction (STEMI)] or old myocardial infarction (OMI), or patients without coronary heart disease (non-CAD) were retrospectively enrolled in this study. For CAD patients undergoing PCI, standard dual antiplatelet therapy (100 mg aspirin and 75 mg clopidogrel) was prescribed. After administration of dual antiplatelet agents for at least 5 days, whole blood samples were collected and platelet function was tested using thrombelastography (TEG). Thrombin-induced platelet-fibrin clot strength (MAthrombin) and ADPinduced platelet-fibrin clot strength (MAADP) were measured to assess the hypercoagulability and antiplatelet effects. RESULTS: A total of 571 patients, including 479 ACS patients, 21 OMI patients and 71 non-CAD patients were enrolled. Highest level of MAthrombin was detected in STEMI patients, while lowest MAthrombin level was observed in non-CAD patients (P1 <0.05 for OMI vs. non-CAD; P2 <0.001 for ACS vs. non-CAD; P3<0.05 among ACS). Higher MAADP was also observed in STEMI and NSTEMI patients compared with UA patients (P<0.001). When MAADP was divided into trisections (MAADP <31; 31-47; >47 mm), a considerable portion of 41.8% ACS patients were in the first trisection (MAADP <31 mm), containing 50.4% of UA patients, 35.7% of NSTEMI patients and 26.5% of STEMI patients, with significant difference being observed between UA patients and other ACS patients (P<0.05 for NSTEMI vs. UA; P<0.001 for STEMI vs. UA). Meanwhile, 27.6% of NSTEMI and 31.0% of STEMI patients were in the third trisection (MAADP >47 mm), which was significantly higher than that of UA patients (12.7%) (P<0.001 for NSTEMI or STEMI vs. UA). CONCLUSIONS: Considering various degrees of hypercoagulability and antiplatelet effects of clopidogrel among OMI and ACS patients post-PCI. More attention should be paid to personalized antiplatelet therapy according to individual's effects of P2Y12 receptor inhibitors.

Low molecular weight heparin once versus twice for thromboprophylaxis following esophagectomy: a randomised, double-blind and placebo-controlled trial.

BACKGROUND: Venous thromboembolism (VTE) remained common complication following surgical resection of esophageal cancer. In this prospective randomized double-blind placebo-controlled trial (NCT01267305), we aim to compare the safety and efficacy between low molecular weight heparin (LMWH) once-daily (QD) and twice-daily (BID) for the prophylaxis of VTE following esophagectomy. METHODS: During August 2012 to July 2013, patients underwent esophagectomy were randomly assigned to nadroparin calcium QD (4,100 AxaIU qd + placebo qd, group QD), or nadroparin calcium BID (4,100 AxaIU q12h, group BID) in the prophylaxis of VTE. All patients received thrombelastography (TEG) before and 0/24/48/72 hours after operation. Daily vascular ultrasound of lower extremities was followed during the first 7 postoperative days to confirm the suspected deep venous thrombosis (DVT). Cumulatively postoperative chest drainage at 72 hours after the surgery was collected to identify the difference in volume and red blood cell (RBC) counts between the two groups. Any bleeding events and thromboembolic events were also documented. RESULTS: A total of 117 patients were enrolled in this study, and 111 eligible patients were randomly assigned (group QD: 55 patients; group BID: 56 patients). Patients' clinical features were close between the two groups. TEG analysis [R time, K time, alpha angel and maximum amplitude (MA)] before and instantly after operation showed nearly identical results. However, compared with group QD, all TEG measurements of 24/48/72 hours postoperatively showed significantly prolonged R time and K time, and decreased alpha angel in group BID. In ultrasound follow-ups, a total of four cases of DVT (four cases in group QD and no case in group BID) were found in this cohort (7.27% versus 0%, P=0.046), and one case of pulmonary embolism (PE) (in group QD) was observed. The incidence of VTE was lower in group BID (9.09% versus 0%, P=0.032). At 72 hours after surgery, the cumulative volume of chest drainage were close between these two groups (1,001.39±424.58 versus 1,133.61±513.93 mL, P=0.406). RBC counts in chest drainage were also identical between two groups [(2.56±1.98)×10(5) versus (2.71±4.67)×10(5), P=0.61]. No patient died due to VTE or bleeding events. CONCLUSIONS: For the prophylaxis of VTE, BID LMWH provided more potent efficacy and equal safety when compared to QD LMWH in patients undergoing selective esophagectomy. Further study based on larger population is required to confirm these findings.

Association between thrombelastography system and vascular obstructions and hemorrhage: a two-year follow-up study of elderly Chinese patients.

OBJECTIVES: This study was designed to test the hypothesis that prior thrombelastography (TEG) indices are associated with subsequent vascular obstructions and hemorrhage events in aged populations, as well as to obtain knowledge about the distribution of TEG indices in elderly Chinese patients. METHODS: We conducted a two-year follow-up study. The study population consisted of patients older than 65 years who had TEG in the Chinese PLA General Hospital between January 2007 and December 2010. Four hundred and three patients were enrolled in our study. They received TEG measurements upon being enrolled in this study. We collected information on demographics, clinical examinations, and outcomes during the observational period. Structural equation modeling (SEM) was used to analyze the relationship between "synthesized" TEG parameter indices and the outcome via an indicator pathway. RESULTS: We found that in the "model of hemorrhage" (adjusted by confounding of anticoagulants), the model fit indices with chi-square/df = 9.555/7, CFI of 0.997, TLI of 0.994, and standardized root mean square residual (SRMR) of 0.034; while in the "model of vascular obstruction events" (adjusted by confounding of Anticoagulants), the model fit indices with chi-square/df = 6.070/7, CFI of 1.000, TLI of 1.002, and standardized root mean square residual (SRMR) of 0.000. The "model of vascular obstruction events" showed that the "synthesized" TEG parameter was significantly associated with vascular obstruction events, while this significance was not found in the "model of hemorrhage". CONCLUSIONS: Previous TEG indices are significantly associated with the subsequent vascular obstruction events in the elderly population. Future study can test this association and provide more information for clinical use.

Association between thrombelastography system and thromboembolic and bleeding events in Chinese aged people.

OBJECTIVES: This study was designed to obtain the knowledge about TEG indexes distribution in Chinese aged people, as well as to test the hypothesis that previous TEG indexes are associated with the subsequent thromboembolic and bleeding events in the aged population. METHODS: We conducted a two-year follow-up study in Chinese PLA General Hospital, Beijing, China. 403 aged people were enrolled in our study. They received TEG measurements at least once when they entered this study. We collected their demographical characteristics, clinical examination information and their outcome during their observational period. Structural equation modeling (SEM) was used to analyze the relationship between the four indexes from TEG and the outcome via a pathway of indicator. RESULTS: We found that in the "model of bleeding" (adjusted by confounding of Anticoagulants), the model fit indices with chi-square/df = 9.555/7, CFI was 0.997, TLI was 0.994 and standardized root mean square residual (SRMR) was 0.034; while in the "model of thromboembolic events" (adjusted by confounding of Anticoagulants), the model fit indices with chi-square/df = 6.070/7, CFI was1.000, TLI was 1.002 and standardized root mean square residual (SRMR) was 0.000. The "model of thromboembolic events" showed that the four indexes (R, K, MA and ANGLE) were all significantly associated with thromboembolic events, while this significance was not found in the "model of bleeding". CONCLUSIONS: Previous TEG indexes are significantly associated with the subsequent thromboembolic events in the aged population. Future study can test this association and provide more information for the clinical use.