Fibrin clot strength measured by thrombelastography and outcomes after percutaneous coronary intervention

Platelet-fibrin clot strength and platelet reactivity predicting cardiovascular events after percutaneous coronary interventions

BACKGROUND AND AIMS

Platelet-fibrin clot strength (PFCS) is linked to major adverse cardiovascular event (MACE) risk. However, the association between PFCS and platelet reactivity and their prognostic implication remains uncertain in patients undergoing percutaneous coronary intervention (PCI).

METHODS

In PCI-treated patients (n = 2512) from registry data from January 2010 to November 2018 in South Korea, PFCS using thromboelastography and platelet reactivity using VerifyNow were measured. High PFCS (PFCSHigh) was defined as thromboelastography maximal amplitude ≥ 68 mm, and high platelet reactivity (HPR) was defined as >208 P2Y12 reaction units. Patients were stratified into four groups according to maximal amplitude and P2Y12 reaction unit levels: (i) normal platelet reactivity (NPR)-PFCSNormal (31.8%), (ii) HPR-PFCSNormal (29.0%), (iii) NPR-PFCSHigh (18.1%), and (iv) HPR-PFCSHigh (21.1%). Major adverse cardiovascular event (all-cause death, myocardial infarction, or stroke) and major bleeding were followed up to 4 years.

RESULTS

High platelet reactivity and PFCSHigh showed an additive effect for clinical outcomes (log-rank test, P < .001). Individuals with NPR-PFCSNormal, NPR-PFCSHigh, HPR-PFCSNormal, and HPR-PFCSHigh demonstrated MACE incidences of 7.5%, 12.6%, 13.4%, and 19.3%, respectively. The HPR-PFCSHigh group showed significantly higher risks of MACE compared with the NPR-PFCSNormal group [adjusted hazard ratio (HRadj) 1.89; 95% confidence interval (CI) 1.23-2.91; P = .004] and the HPR-PFCSNormal group (HRadj 1.60; 95% CI 1.12-2.27; P = .009). Similar results were observed for all-cause death. Compared with HPR-PFCSNormal phenotype, NPR-PFCSNormal phenotype was associated with a higher risk of major bleeding (HRadj 3.12; 95% CI 1.30-7.69; P = .010).

CONCLUSIONS

In PCI patients, PFCS and platelet reactivity demonstrated important relationships in predicting clinical prognosis. Their combined assessment may enhance post-PCI risk stratification for personalized antithrombotic therapy.

The impact of high on-treatment platelet reactivity and fibrinogen levels on ischemic events in patients with ST elevation myocardial infarction: a prospective observational study

BACKGROUND

After treatment, high residual platelet reactivity (HRPR) is considered as an essential risk factor for recurrent ischemic events.

AIM

To evaluate the impact of fibrinogen on HRPR after implantation of emergency drug-eluting stents (DES) in patients treated with aspirin and clopidogrel or ticagrelor due to ST-elevation myocardial infarction (STEMI) and to explore the predictive values of HRPR and fibrinogen for adverse ischemic events at 12 months.

METHOD

This single-center prospective observational study analyzed patients with STEMI who underwent primary percutaneous coronary intervention (PCI) with second-generation DES implantation from January 2017 to December 2018. Platelet reactivity was measured by thromboelastography (TEG) at 60-72 h after primary PCI. HRPR was defined as the adenosine diphosphate-induced maximum amplitude (MA_ADP) > 47 mm.

RESULTS

A total of 919 patients were analyzed, of which 512 (55.8%) received aspirin and clopidogrel and 406 (44.2%) received aspirin and ticagrelor. Elevated fibrinogen levels were associated with an increased prevalence of HRPR (P < 0.001). High fibrinogen (quartile IV, ≥ 410 mg/dL) was an independent risk factor for HRPR after multivariate regression (odds ratio 6.556, 95% confidence interval [CI]: 3.200-13.431, P < 0.001). When analyzed by Kaplan-Meier survival curves, the combination of high fibrinogen and HRPR was strongly predictive for ischemic major adverse cardiac events at 12 months compared to the group without HRPR and with low fibrinogen (hazard ratio 9.681, 95% CI: 4.467-20.98, log-rank P < 0.001). Similar results were confirmed in subgroups according to different dual antiplatelet therapies.

CONCLUSION

A combination of high fibrinogen and HRPR may identify recurrent adverse ischemic events over 12 months. Ticagrelor exhibited more potent platelet inhibition and a better prognosis than clopidogrel.

MicroRNA sequencing in patients with coronary artery disease – considerations for use as biomarker for thrombotic risk

MicroRNAs (miRNAs) are small RNAs integral in the regulation of gene expression. Analysis of circulating miRNA levels may identify patients with coronary artery disease (CAD) at risk for recurrent myocardial infarction (MI) after percutaneous coronary interventions (PCIs). Subjects with CAD were selected from the GENCATH cardiac catheterization biobank. Subjects with recurrent MI after PCI were compared with those without recurrent MI during follow‐up in the initial (n = 48) and replication cohort (n = 67). Next generation MiRNA sequencing was performed on plasma samples and whole blood samples fixed with PAXGENE tubes upon collection. Overall, 164 miRNAs derived from whole blood were differentially expressed in the replication cohort between subjects with and without recurrent MI events (p < 0.05), with 69 remaining significant after false‐discovery rate (FDR) correction. None of the miRNAs in plasma was significantly different by FDR among subjects with and without MI. Overall, correlation between direction of effects between plasma and whole blood assays was variable, and only two miRNAs were concordant and significant in both. Associations of miRNA with vascular disease, MI, and thrombosis were further explored. MiRNA profiling has potential as the future biomarker for disease prognosis and treatment response marker in secondary treatment of patients with CAD after PCI. Whole blood may be the preferred sample source as compared to plasma.

Association Between Thromboelastography and Coronary Heart Disease

BACKGROUND Thromboelastography (TEG) is a novel blood viscoelasticity detection method revealing blood coagulation status and has been reported to be helpful in predicting clinical outcomes in patients with cardiovascular diseases (CVD). In this study, we aimed to investigate the association between TEG and CVD. MATERIAL AND METHODS A single-center case-control study was performed. Individuals who took TEG tests at Tongji Hospital in Wuhan, China from 2015 to 2019 were included. The nearest-neighbor Mahalanobis matching with replacement, within propensity score calipers of 0.25 was used to control the covariate imbalance between CVD patients and controls. Logistic regression analyses were conducted to assess the relationship between TEG and CVD. Subgroup and sensitivity analyses were performed to evaluate the robustness of the association between TEG and CVD. RESULTS After matching, a total of 151 participants were included in this study, with 83 patients having CVD (49 patients having coronary heart disease [CHD] and 34 patients having an ischemic stroke). By comparison, CHD patients had a significantly higher maximum amplitude (MA) (P=0.02) than controls. After multivariable adjustment, MA (OR 1.11, 95% CI 1.01-1.24, P=0.04) was independently associated with CHD. The association between MA and CHD remained robust across subgroups and in sensitivity analyses. CONCLUSIONS The current study suggests that MA is significantly associated with CHD. Enhanced platelet reactivity as described by high MA might be associated with risk of CHD. The exact role of MA in the measurement of CHD risk needs to be further examined in large-scale prospective cohort studies.

Fibrinolysis in Acute and Chronic Cardiovascular Disease

The formation of an obstructive thrombus within an artery remains a major cause of mortality and morbidity worldwide. Despite effective inhibition of platelet function by modern antiplatelet therapies, these agents fail to fully eliminate atherothrombotic risk. This may well be related to extensive vascular disease, beyond the protective abilities of the treatment agents used. However, recent evidence suggests that residual vascular risk in those treated with modern antiplatelet therapies is related, at least in part, to impaired fibrin clot lysis. In this review, we attempt to shed more light on the role of hypofibrinolysis in predisposition to arterial vascular events. We provide a brief overview of the coagulation system followed by addressing the role of impaired fibrin clot lysis in acute and chronic vascular conditions, including coronary artery, cerebrovascular, and peripheral vascular disease. We also discuss the role of combined anticoagulant and antiplatelet therapies to reduce the risk of arterial thrombotic events, addressing both efficacy and safety of such an approach. We conclude that impaired fibrin clot lysis appears to contribute to residual thrombosis risk in individuals with arterial disease on antiplatelet therapy, and targeting proteins in the fibrinolytic system represents a viable strategy to improve outcome in this population. Future work is required to refine the antithrombotic approach by modulating pathological abnormalities in the fibrinolytic system and tailoring therapy according to the need of each individual.

Recent Progress on Biodegradable Tissue Engineering Scaffolds Prepared by Thermally-Induced Phase Separation (TIPS)

Porous biodegradable scaffolds provide a physical substrate for cells allowing them to attach, proliferate and guide the formation of new tissues. A variety of techniques have been developed to fabricate tissue engineering (TE) scaffolds, among them the most relevant is the thermally-induced phase separation (TIPS). This technique has been widely used in recent years to fabricate three-dimensional (3D) TE scaffolds. Low production cost, simple experimental procedure and easy processability together with the capability to produce highly porous scaffolds with controllable architecture justify the popularity of TIPS. This paper provides a general overview of the TIPS methodology applied for the preparation of 3D porous TE scaffolds. The recent advances in the fabrication of porous scaffolds through this technique, in terms of technology and material selection, have been reviewed. In addition, how properties can be effectively modified to serve as ideal substrates for specific target cells has been specifically addressed. Additionally, examples are offered with respect to changes of TIPS procedure parameters, the combination of TIPS with other techniques and innovations in polymer or filler selection.

Fibrin clot properties independently predict adverse clinical outcome following acute coronary syndrome: a PLATO substudy

Aims

To determine whether fibrin clot properties are associated with clinical outcomes following acute coronary syndrome (ACS).

Methods and results

Plasma samples were collected at hospital discharge from 4354 ACS patients randomized to clopidogrel or ticagrelor in the PLATelet inhibition and patient Outcomes (PLATO) trial. A validated turbidimetric assay was employed to study plasma clot lysis time and maximum turbidity (a measure of clot density). One-year rates of cardiovascular (CV) death, spontaneous myocardial infarction (MI) and PLATO-defined major bleeding events were assessed after sample collection. Hazard ratios (HRs) were estimated using Cox proportional hazards models. After adjusting for CV risk factors, each 50% increase in lysis time was associated with CV death/spontaneous MI [HR 1.17, 95% confidence interval (CI) 1.05-1.31; P < 0.01] and CV death alone (HR 1.36, 95% CI 1.17-1.59; P < 0.001). Similarly, each 50% increase in maximum turbidity was associated with increased risk of CV death (HR 1.24, 95% CI 1.03-1.50; P = 0.024). After adjustment for other prognostic biomarkers (leukocyte count, high-sensitivity C-reactive protein, high-sensitivity troponin T, cystatin C, N-terminal pro B-type natriuretic peptide, and growth differentiation factor-15), the association with CV death remained significant for lysis time (HR 1.2, 95% CI 1.01-1.42; P = 0.042) but not for maximum turbidity. These associations were consistent regardless of randomized antiplatelet treatment (all interaction P > 0.05). Neither lysis time nor maximum turbidity was associated with major bleeding events.

Conclusion

Fibrin clots that are resistant to lysis independently predict adverse outcome in ACS patients. Novel therapies targeting fibrin clot properties might be a new avenue for improving prognosis in patients with ACS.

Application value of thromboelastography in perioperative clinical blood transfusion and its effect on the outcome of patient

Application value of thromboelastography (TEG) in perioperative clinical blood transfusion and its effect on the outcome of patient were investigated. Seventy-four patients, admitted to The Surgical Department of the First Hospital of Zibo from March 2015 to March 2018, were selected for this study. Among them, 34 patients took only the traditional coagulation function testing method as the blood transfusion guide during the perioperative period and they were regarded as the control group. The other 40 patients used TEG as the blood transfusion guide during the perioperative period, and they were regarded as the TEG group. The coagulation function indicators in 2 h before the operation and in 24 h after the operation, the transfusion amount and blood loss during the operation, the condition of the blood transfusion during the perioperative period, the occurrence rate of the postoperative rebleeding, the length of hospital stay and mortality of the patients in the two groups were compared. The coagulation function indicators of the patients in the two groups in 2 h before the operation and in 24 h after the operation showed that there was no significant difference between the two groups (P>0.050). However, APTT and Pt of the patients in the two groups both increased when compared with those before the treatment (P<0.050) and Hb, Hct, Plt and Fib all decreased (P<0.050). The suspended erythrocytes, Plt, fibrinogen and plasma in the TEG group were both significantly lower than those in the control group (P<0.001). Compared with the traditional coagulation function test, TEG was more accurate for estimating the coagulation function of patient and was more suitable for estimating the condition of blood transfusion of patient in the perioperative period; also, it could shorten the recovery period of patient and it is worthwhile to promote it in the clinic.

Patho- physiological role of BDNF in fibrin clotting

Circulating levels of Brain Derived Neurotrophic Factor (BDNF) are lower in coronary heart disease (CHD) than in healthy subjects and are associated with coronary events and mortality. However, the mechanism(s) underling this association is not fully understood. We hypothesize that BDNF may influence fibrin fiber structure and clot stability, favoring clot lysis and thrombus resolution. We showed that recombinant BDNF (rh-BDNF) influenced with clot formation in a concentration-dependent manner in both purified fibrinogen and plasma from healthy subjects. In particular, rh-BDNF reduced the density of fibrin fibers, the maximum clot firmness (MCF) and the maximum clot turbidity, and affected the lysis of clot. In addition, both thrombin and reptilase clotting time were prolonged by rh-BDNF, despite the amount of thrombin formed was greater. Intriguingly, CHD patients had lower levels of BDNF, greater fibrin fibers density, higher MCF than control subjects, and a negative correlation between BDNF and MCF was found. Of note, rh-BDNF markedly modified fibrin clot profile restoring physiological clot morphology in CHD plasma. In conclusion, we provide evidence that low levels of BDNF correlate with the formation of bigger thrombi (in vitro) and that this effect is mediated, at least partially, by the alteration of fibrin fibers formation.

Facile preparation of a controlled-release tubular scaffold for blood vessel implantation

Salvianic acid-loaded mesoporous silica nanoparticles into gelatin/polyurethane bilayered small-diameter tubular scaffold were prepared by thermally induced phase separation (TIPS) and electrospinning. Mesoporous silica nanoparticles (MSNs) were selected as carriers to load salvianic acid (SAL). The SAL-loaded MSNs (SAL@MSNs) with an optimized SAL loading efficiency of 10% was initially dispersed in gelatin solution and under a vacuum freeze-drying process as an inner layer of vascular scaffolds. Then, poly(ester-urethane)urea (C-PEEUU) nanofibers were electrospun outside the SAL@MSNs/Gelatin vascular scaffold to strengthen the spongy matrix. The loaded SAL within the MSNs/Gelatin/C-PEEUU bilayered small-diameter tubular scaffold showed a sustained release profile and good mechanical properties. In addition, the drug-loaded composite scaffold showed no unfavorable effects on the adhesion and proliferation of endothelial cells. Moreover, no intimal hyperplasia and acute thrombosis was observed in the short-term implantation in rabbit's carotid artery. We believe the SAL@MSNs/Gelatin/C-PEEUU bilayered vascular scaffolds have promise for vascular tissue engineering applications.

Prediction of Ischemic Events after Percutaneous Coronary Intervention: Thrombelastography Profiles and Factor XIIIa Activity

Background  High plasma fibrin clot strength (MA) measured by thrombelastography (TEG) is associated with increased risk of cardiac events after percutaneous coronary interventions (PCIs). Factor XIIIa (FXIIIa) cross-links soluble fibrin, shortens clot formation time (TEG-K), and increases final clot strength (MA).

Methods  We analyzed platelet-poor plasma from patients with previous PCI. Kaolin-activated TEG (R, K, MA) in citrate platelet-poor plasma and FXIIIa were measured ( n  = 257). Combined primary endpoint was defined as recurrent myocardial infarction (MI) or cardiovascular death (CVD). Relationship of FXIIIa and TEG measurements on cardiac risk was explored.

Results  FXIIIa correlated with TEG-MA ( p  = 0.002) and inversely with TEG-K ( p  < 0.001). High MA (≥35.35 mm; p  = 0.001), low K (<1.15 min; p  = 0.038), and elevated FXIIIa (≥83.51%; p  = 0.011) were associated with increased risk of CVD or MI. Inclusion of FXIIIa activity and low TEG-K in risk scores did not improve risk prediction as compared with high TEG-MA alone.

Conclusion  FXIIIa is associated with higher plasma TEG-MA and low TEG-K. High FXIIIa activity is associated with a modest increase in cardiovascular risk after PCI, but is less sensitive and specific than TEG-MA. Addition of FXIIIa does not provide additional risk stratification beyond risk associated with high fibrin clot strength phenotype measured by TEG.

Fibrin Clot Strength in Patients with Diabetes Mellitus Measured by Thrombelastography

BACKGROUND

Patients with diabetes mellitus (DM) exhibit increased risk of recurrent myocardial infarction. Maximal clot strength measured by thrombelastography (TEG) is a risk factor for recurrent ischemic events. We hypothesized that diabetic subjects exhibit increased fibrin clot strength in platelet-poor plasma and that glycemic control correlates with maximal fibrin clot strength.

METHODS

We collected plasma samples from subjects with known or suspected coronary artery disease undergoing cardiac catheterization (n = 354). We measured kaolin-activated TEG in platelet-poor citrate plasma. Time to fibrin formation (R), clot formation time (K), and maximal fibrin clot strength (MA) were recorded.

RESULTS

Plasma fibrin MA was increased among subjects with DM (n = 152) as compared to non-DM (n = 202) (37.0 ± 8 versus 34.1 ± 8 mm; p < 0.001). Hemoglobin A1c (HbA1c) (ρ = 0.22; p = 0.001) and fibrinogen (ρ = 0.29; p < 0.001) correlated with fibrin MA. In multivariable regression analysis, DM remained significantly associated with plasma MA after adjustment for fibrinogen level (p = 0.003).

CONCLUSIONS

Subjects with diabetes mellitus exhibit increased maximal fibrin clot strength measured by TEG in platelet-poor plasma.