Most Recent Evidence Behind Aggregometry and Genotyping Methods as Platelet Function Testing for Tailored Anti-Platelet Treatment Among PCI Patients

Abstract

Aggregometry and genotyping are methods of platelet function testing, which can be beneficial for high-risk patients undergoing invasive cardiac procedures. An optimal level of platelet reactivity (PR) should be maintained. There are discrepancies between individuals and their response to clopidogrel, accounting for the incidence of poor responders from 5% to 44%. This phenomenon predisposes the patients to increased risk of ischaemic events and thereby overall poorer clinical outcome. Prasugrel and tricagrelor are newer without genetic correlation to their action, however associated with increased bleeding risk. Aggregometry methods assess platelet reactivity at the exact moment of blood sampling. They reflect "phenotype" of the patient and vary after drug administration or dose change. The most popular tests are Light Transmission Aggregometry, Vasodilator-Stimulated Protein, VerifyNow, Multiple Electrode Aggregometry and Thrombelastography. There is proven genetic correlation between some cytochrome enzymes on clopidogrel response. The most widely tested is gene CYP2C19, which produces the enzyme transforming clopidogrel into an active metabolite. The CYP2C19*2 allele carriers have higher PR which can result in more thrombotic events. The manuscript shows the most recent evidence behind platelet function testing. Aggregometry is shown to be beneficial in 5 trials and 1 meta-analysis, while one paper was of different opinion. Ten studies show a positive clinical effect of genotyping on patients' outcome, while one does not support it. The best method of identifying high-risk individuals could be both methods and personalisation of antiplatelet therapy may decrease adverse ischaemic outcomes (Adv Clin Exp Med 2015, 24, 4, 687-693).

Comparison of Commercially Available Blood Collection Tubes Containing Sodium Citrate and Hirudin in Platelet Aggregation Testing

“…Platelet function testing has a central role in the management of patients with suspected platelet disfunction [ 1 ], as well as in patients who are at risk of thrombosis who receive anti-platelet therapy [ 12 ]. Platelet reactivity, as measured by platelet aggregometry, is a very useful tool in predicting patient response to anti-platelet therapy and in predicting the risk of restenosis following surgical interventions such as percutaneous coronary interventions [ 12 , 13 ]. The clinical applications of platelet reactivity testing has put a focus on development of novel strategies for platelet reactivity assessment [ 14 ].…”

Administration of Ticagrelor and Double-Dose Clopidogrel Based on Platelet Reactivity Determined by VerifyNow-P2Y12 for Chinese Subjects After Elective PCI

“…16) Most importantly, previous studies have suggested the VerifyNow system was well correlated with the gold standard light transmission aggregometry. 17,18) Increasing evidence suggests that high residual platelet reactivity detected by VerifyNow assay predicts clinical outcome and adverse cardiovascular events in patients undergoing percutaneous coronary intervention.…”

Monitoring the hemostasis with rotation thromboelastometry in patients with acute STEMI on dual antiplatelet therapy

“…A wide scale of the assays for the monitoring of antiplatelet therapy including turbidimetric light transmission aggregometry (LTA), whole blood aggregometry, assessment of platelet reactivity index or bleeding time, platelet function analyzer (100), the VerifyNow system, Multiplate impedance platelet aggregometry, flow cytometric analysis of the phosphorylation state of the vasodilator stimulated phosphoprotein, flow cytometric analysis of platelet functions in general, Ichor-Plateletworks, HemoStatus device, Impact cone and plate(let) analyzer, or thromboelastography (TEG) are recently available in clinical practice. [ 6 ] Rotation thromboelastometry (ROTEM) is a new viscoelastometric point-of-care-test for the complex evaluation of changes in hemostasis recently introduced to clinical practice. [ 7 ] This assay allows quick complex testing of hemostasis in one blood sample.…”