Impact of platelet reactivity to adenosine diphosphate before implantation of drug-eluting stents on subsequent adverse cardiac events in patients with stable angina

Thrombin-induced platelet-fibrin clot strength: Relation to high on-clopidogrel platelet reactivity, genotype, and post-percutaneous coronary intervention outcomes

The relationship between thrombin-induced platelet-fibrin clot strength (MATHROMBIN), genotype and high on-treatment platelet reactivity (HPR) is unknown. The aim of this study is to assess the influence of MATHROMBIN measured by thrombelastography on HPR and long-term major adverse cardiovascular events (MACE) in percutaneous coronary intervention (PCI)-treated patients during aspirin and clopidogrel therapy. MATHROMBIN, platelet aggregation, genotype, and two-year MACE were assessed in 197 PCI-treated patients. HPR was defined as 5 µM ADP-induced PR46% measured by conventional aggregometry. Both high MATHROMBIN ( 68 mm) and CYP2C19*2 allele carriage were independently associated with ADP-induced platelet aggregation ([uni03B2] coefficient: 8.3% and 12.0%, respectively). The combination of CYP2C19*2 allele carriage and high MATHROMBIN increased the predictive value for the risk of HPR (odds ratio: 13.89; 95% confidence interval: 3.41 to 55.56; p < 0.001). MACE occurred in 25 patients (12.7%). HPR and high MATHROMBIN were both associated with MACE (hazard ratio: 3.09 and 2.24, respectively), and patients with both HPR and high MATHROMBIN showed an increased risk for MACE (adjusted hazard ratio: 5.56; 95% confidence interval: 1.85 to 16.67; p = 0.002). In conclusion, this is the first study to demonstrate that high platelet-fibrin clot strength is an independent determinant of HPR in PCI-treated patients. Combining the measurements of platelet aggregation and platelet-fibrin clot strength may enhance post-PCI risk stratification and deserves further study.

Individualized dual antiplatelet therapy based on platelet function testing in patients undergoing percutaneous coronary intervention: a meta-analysis of randomized controlled trials

Background

High on-treatment platelet reactivity (HPR) represents a strong risk factor for thrombotic events after PCI. We aim to evaluate the efficacy and safety of individualizing intensified dual antiplatelet therapy (DAPT) in PCI-treated patients with HPR based on platelet function testing (PFT).

Methods

Electronic databases were searched for randomized control trials that reported the clinical outcomes of using an intensified antiplatelet protocol with P2Y₁₂ receptor inhibitor comparing with standard maintenance dose of clopidogrel on the basis of platelet function testing. Clinical endpoints were assessed.

Results

From 2005 to 2016, thirteen clinical studies comprising 7290 patients were included for analysis. Compared with standard antiplatelet therapy with clopidogrel, the intensified protocol based on platelet function testing was associated with a significant reduction in major adverse cardiovascular events (RR:0.55, 95% CI: 0.36–0.84, p = 0.005), cardiovascular death (RR:0.60, 95% CI: 0.38–0.96, p = 0.03), stent thrombosis (RR:0.58, 95% CI: 0.36–0.93, p = 0.02) and target vessel revascularization (RR:0.33, 95% CI: 0.14–0.76, p = 0.009). No significant difference was found in the rate of bleeding events between intensified and standard protocol.

Conclusions

Compared with standard clopidogrel therapy, individualized intensified antiplatelet therapy on the basis of platelet reactivity testing reduces the incidence of cardiovascular events in patient undergoing PCI, without increasing the risk of bleeding.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-017-0582-6) contains supplementary material, which is available to authorized users.

Impact of cytochrome P450 2C19 loss-of-function polymorphism on intra-stent thrombi and lesion outcome after everolimus-eluting stent implantation compared to that after first-generation drug-eluting stent implantation

BACKGROUND

The contribution of clopidogrel response due to cytochrome P450 (CYP) 2C19 loss-of-function polymorphism after drug-eluting stent (DES) implantation is unclear.

METHODS

A total of 196 patients who had undergone optical coherence tomography (OCT) at 8 months following first-generation DES (120 lesions) and current-generation everolimus-eluting stent (EES) implantation (127 lesions) were enrolled. Patients were divided into 3 groups by CYP2C19 polymorphism: extensive metabolizers (EMs), intermediate metabolizers (IMs), and poor metabolizers (PMs). OCT findings were compared among the 3 groups. Responsiveness to clopidogrel was assessed by VerifyNow platelet reactivity unit (PRU).

RESULTS

The incidence of intra-stent thrombi was significantly higher after first-generation DES implantation compared with EES implantation (35% vs 13%, respectively; p=0.0001). In the first-generation DES group, the incidence of intra-stent thrombi significantly increased among EMs, IMs, and PMs (21% vs 36% vs 63%, respectively; p=0.007), while there was no significant difference among the 3 groups after EES implantation (10% vs 13% vs 20%, respectively; p=0.55). The PRU significantly increased among EMs, IMs, and PMs in each stent group. In multivariate analyses, although PMs had a 3-fold higher risk of thrombi formation compared with non-PMs after first-generation DES implantation, there were no significant differences in thrombi formation between the 2 groups after EES implantation. The optimal PRU cutoff values for the prediction of intra-stent thrombi with first-generation DES and EES were 234 and 256, respectively.

CONCLUSION

CYP2C19 loss-of-function polymorphism is associated with a higher incidence of intra-stent thrombi after first-generation DES implantation, while the impact is attenuated following EES implantation.

The prognostic impact of high on-treatment platelet reactivity with aspirin or ADP receptor antagonists: systematic review and meta-analysis

OBJECTIVE

Negative results of recent randomized clinical trials testing the hypothesis of target therapy for patients with high on-treatment platelet reactivity (HOPR) have questioned its independent impact on clinical outcomes. 26 studies with 28.178 patients were included, with a median age of 66.8 (64-68) and 22.7% (22.4-27.8), of female gender. After a median follow-up of 1 year (0.1-1), cardiac adverse events occurred in 8.3% (3-11; all results are reported as median and interquartile range) of patients. Pooling all studies together, on-treatment platelet reactivity significantly increased the risk of adverse events (OR 1.33 [1.09, 1.64], I(2) = 0%). However, a sensitivity analysis showed that HOPR did not increase the risk of adverse events for patients with ACS, AMI, or stable angina as well as patients resistant to aspirin, ADP antagonists, or both. For all studies, publication bias was formally evident; after adjusting for this, HOPR did not significantly increase adverse cardiac events (OR 1.1 : 0.89-1.22, I(2) 0%).

CONCLUSIONS

After adjusting for clinical confounders (like risk factors and clinical presentation) and for relevant publication bias, HOPR was not an independent prognostic indicator in unselected patients with both stable and unstable coronary disease for an adverse cardiac event. The clinical importance of HOPR for high-risk populations remains to be assessed.

Impact of proton pump inhibitors or famotidine on the antiplatelet actions during dual-antiplatelet therapy in Japanese patients

BACKGROUND

It has been reported that the antiplatelet action becomes attenuated when a proton pump inhibitor is used in combination with clopidogrel.

PURPOSE

The effect of an antacid causing platelet aggregation during the administration of clopidogrel was investigated.

SUBJECTS AND METHODS

The subjects consisted of 265 patients with coronary artery disease. Platelet aggregation function testing (light transmittance aggregometry) was conducted while aspirin and clopidogrel 75 mg were taken orally and the minimum concentration of aggregation induction platelet aggregation threshold index was measured. The ADP-PATI, measured with ADP as the inducing substance, was compared and investigated according to the type of concomitantly used antacid.

RESULT

The results of the ADP-PATI were: control group: 3.47 ± 0.95 μM (N = 67), famotidine group: 3.80 ± 0.52 μM (N = 32), rabeprazole group: 3.43 ± 0.93 μM (N = 87), lansoprazole group: 3.28 ± 1.04 μM (N = 63) and omeprazole group: 3.33 ± 0.81 μM (N = 16). No statistically significant difference was observed regarding the ADP-PATI of respective groups compared to the control group.

CONCLUSION

The concomitant use of famotidine, rabeprazole, lansoprazole, and omeprazole did not affect the antiplatelet action of clopidogrel in Japanese patients.