Viscoelastic Haemostatic Assays in Cardiovascular Critical Care

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.

The Use of Thromboelastography in Percutaneous Coronary Intervention and Acute Coronary Syndrome in East Asia: A Systematic Literature Review

Dual antiplatelet therapy (DAPT), alongside percutaneous coronary intervention (PCI), is central to the prevention of ischemic events following acute coronary syndrome (ACS). However, response to therapy can vary due to several factors including CYP2C19 gene variation, which shows increased prevalence in East Asian populations. DAPT responsiveness can be assessed using techniques such as light transmission aggregometry (LTA), VerifyNow^® and thromboelastography with the PlateletMapping^® assay, and there is increasing focus on the utility of platelet function testing to guide individualized treatment. This systematic literature review of one English and three Chinese language databases was conducted to evaluate the evidence for the utility of thromboelastography in ACS/PCI in East Asia. The search identified 42 articles from the English language and 71 articles from the Chinese language databases which fulfilled the pre-determined inclusion criteria, including 38 randomized controlled trials (RCTs). The identified studies explored the use of thromboelastography compared to LTA and VerifyNow in monitoring patient responsiveness to DAPT, as well as predicting ischemic risk, with some studies suggesting that thromboelastography is better able to detect low DAPT response than LTA. Other studies, including one large RCT, described the use of thromboelastography in guiding the escalation of DAPT, with some evidence suggesting that such protocols reduce ischemic events without increasing the risk of bleeding. There was also evidence suggesting that thromboelastography can be used to identify individuals with DAPT hyporesponsiveness genotypes and could potentially guide treatment by adjusting therapy in patients depending on responsiveness.