Decreased platelet inhibition by P2Y12 receptor blockers in anaemia

Age and gender mediated the association between anemia and 30-day outcomes in patients with ST-segment elevated myocardial infarction

Background

The higher prevalence of anemia in females and elderly may be attributed to its association with worsened outcomes in ST-elevation myocardial infarction (STEMI) patients. We aimed to evaluate the precise effects of age and gender on the association between anemia and 30-day outcomes.

Method

We identified 4350 STEMI patients and divided into anemia and non-anemia. Effects were analyzed as categories using Cox proportional-hazards regression and as continuous using restricted cubic splines. Propensity score matching (PSM) and mediation analysis were applied to identify intermediate effects.

Results

Anemic patients were older, more likely to be female, and experienced doubled all-cause death (7.3 % versus 15.0 %), main adverse cardiovascular and cerebrovascular events (MACCE, 11.1 % versus 20.2 %), heart failure (HF, 5.1 % versus 8.6 %), and bleeding events (2.7 % versus 5.4 %). After adjustment, the association between anemia and all-cause death (Hazard ratio (HR) 1.15, 95 % confidence interval (95 %CI) 0.93-1.14), MACCE (HR 1.14, 95 %CI 0.95-1.36) and HF (HR 1.19, 95 %CI 0.92-1.55) were insignificant, the effects persisted nullified across age classes (P-interaction > 0.05) and PSM (P > 0.05). Ulteriorly, age mediated 77.6 %, 66.2 %, 48.0 %, gender mediated 38.1 %, 15.0 %, 3.2 %, age and gender together mediated 99.8 % 72.9 %, 48.1 % of the relationship. Anemia was independently associated with bleeding events (HR 2.02, 95 %CI 1.42-2.88), the effects consisted significant regardless of PSM (P < 0.05), age, and gender classes (P-interaction > 0.05), and no mediating role of age and gender were observed.

Conclusions

In STEMI patients, age and gender largely mediated the relationship between anemia and all-cause death, MACCE, and HF, anemia was independently associated with bleeding complications.

Myocardial Oedema as a Consequence of Viral Infection and Persistence-A Narrative Review with Focus on COVID-19 and Post COVID Sequelae

Microvascular integrity is a critical factor in myocardial fluid homeostasis. The subtle equilibrium between capillary filtration and lymphatic fluid removal is disturbed during pathological processes leading to inflammation, but also in hypoxia or due to alterations in vascular perfusion and coagulability. The degradation of the glycocalyx as the main component of the endothelial filtration barrier as well as pericyte disintegration results in the accumulation of interstitial and intracellular water. Moreover, lymphatic dysfunction evokes an increase in metabolic waste products, cytokines and inflammatory cells in the interstitial space contributing to myocardial oedema formation. This leads to myocardial stiffness and impaired contractility, eventually resulting in cardiomyocyte apoptosis, myocardial remodelling and fibrosis. The following article reviews pathophysiological inflammatory processes leading to myocardial oedema including myocarditis, ischaemia-reperfusion injury and viral infections with a special focus on the pathomechanisms evoked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In addition, clinical implications including potential long-term effects due to viral persistence (long COVID), as well as treatment options, are discussed.

Micro- and Macrovascular Effects of Inflammation in Peripheral Artery Disease-Pathophysiology and Translational Therapeutic Approaches

Inflammation has a critical role in the development and progression of atherosclerosis. On the molecular level, inflammatory pathways negatively impact endothelial barrier properties and thus, tissue homeostasis. Conformational changes and destruction of the glycocalyx further promote pro-inflammatory pathways also contributing to pro-coagulability and a prothrombotic state. In addition, changes in the extracellular matrix composition lead to (peri-)vascular remodelling and alterations of the vessel wall, e.g., aneurysm formation. Moreover, progressive fibrosis leads to reduced tissue perfusion due to loss of functional capillaries. The present review aims at discussing the molecular and clinical effects of inflammatory processes on the micro- and macrovasculature with a focus on peripheral artery disease.

Toll-like Receptors as Pro-Thrombotic Drivers in Viral Infections: A Narrative Review

Toll-like receptors (TLRs) have a critical role in the pathogenesis and disease course of viral infections. The induced pro-inflammatory responses result in the disturbance of the endovascular surface layer and impair vascular homeostasis. The injury of the vessel wall further promotes pro-thrombotic and pro-coagulatory processes, eventually leading to micro-vessel plugging and tissue necrosis. Moreover, TLRs have a direct role in the sensing of viruses and platelet activation. TLR-mediated upregulation of von Willebrand factor release and neutrophil, as well as macrophage extra-cellular trap formation, further contribute to (micro-) thrombotic processes during inflammation. The following review focuses on TLR signaling pathways of TLRs expressed in humans provoking pro-thrombotic responses, which determine patient outcome during viral infections, especially in those with cardiovascular diseases.

Cardiovascular Disease Management in the Context of Global Crisis

The outbreak of coronavirus disease 2019 (COVID-19) initiated a pandemic that has deteriorated health care access and thus disadvantaged vulnerable populations [...].

Impact of hemoglobin levels at admission on outcomes among elderly patients with acute coronary syndrome treated with low-dose Prasugrel or clopidogrel: A sub-study of the ELDERLY ACS 2 trial

Hemoglobin (Hb) levels have emerged as a useful tool for risk stratification and the prediction of outcome after myocardial infarction. We aimed at evaluating the prognostic impact of this parameter among patients in advanced age, where the larger prevalence of anemia and the higher rate of comorbidities could directly impact on the cardiovascular risk.

METHODS

All the patients in the ELDERLY-2 trial, were included in this analysis and stratified according to the values of hemoglobin at admission. The primary endpoint of this study was cardiovascular mortality within one year. The secondary endpoints were all-cause mortality, MI, Bleeding Academic Research Consortium (BARC) type 2-3 or 5 bleeding, any stroke, re-hospitalization for cardiovascular event or stent thrombosis (probable or definite) within 12 months after index admission.

RESULTS

We included in our analysis 1364 patients, divided in quartiles of Hb values (&lt;12.2; 12.2-13.39; 13.44-14.49; ≥ 4.5 g/dl). At a mean follow- up of 330.4 ± 99.9 days cardiovascular mortality was increased in patients with lower Hb (HR[95%CI] = 0.76 [0.59-0.97], p = 0.03). Results were no more significant after correction for baseline differences (adjusted HR[95%CI] = 1.22 [0.41-3.6], p = 0.16). Similar results were observed for overall mortality. At subgroup analysis, (according to Hb median values) a significant interaction was observed only with the type of antiplatelet therapy, but not with major high-risk subsets of patients.

CONCLUSIONS

Among elderly patients with acute coronary syndrome managed invasively, lower hemoglobin at admission is associated with higher cardiovascular and all-cause mortality and major ischemic events, mainly explained by the higher risk profile.

Periprocedural Variability of Platelet Functions in Carotid Artery Stenting: An Analysis Using VerifyNow

Objective

The assessment of platelet functions is necessary to prevent both thromboembolic and hemorrhagic complications under dual antiplatelet therapy (DAPT). Using the VerifyNow (Accumetrics, Inc., San Diego, CA, USA) assay, this study aimed to reveal time-dependent changes in platelet functions after carotid artery stenting (CAS).

Methods

We enrolled retrospectively 43 patients who underwent CAS under DAPT. Aspirin reaction unit (ARU) and P2Y12 reaction unit (PRU) values were determined on the day before and on days 1, 3, and 7 after the procedure. Multiple comparison tests (MCTs) were performed among ARU and PRU measurement points, and the proportions of hypo- and hyper-responses were compared.

Results

The median ARU values were 408 (interquartile range: 392-497) before CAS and 418 (405-470) on day 1, 405 (393.0-460.5) on day 3, and 402 (388.5-477.5) on day 7 (not significant in MCTs). The percentages of hypo-responses were 16.3%, 7.0%, 2.3%, and 7.0%, respectively (p = 0.11). The significantly different median PRU values were 173 (116.5-209.5), 233 (166.5-273.5), 139 (70.5-205.5), and 51 (9.0-79.5), respectively. The median PRU was before the procedure within the therapeutic range but exceeded the upper cutoff on day 1 and was below the lower cutoff on day 7. The percentages of hypo-responses were 14.0%, 51.2%, 18.6%, and 11.6%, respectively (p <0.001) and the percentages of hyper-responses were 9.3%, 2.3%, 23.3%, and 62.8%, respectively (p <0.001).

Conclusion

In the periprocedural CAS period, ARU values were stable, but PRU values showed time-dependent changes. PRU values were above the therapeutic range the day after CAS but decreased below this range on day 7.

Comparison of Light Transmission Aggregometry With Impedance Aggregometry in Patients on Potent P2Y12 Inhibitors

Since data on the agreement between light transmission aggregometry (LTA) and multiple electrode aggregometry (MEA) in patients on the more potent P2Y₁₂ inhibitors are missing so far, we investigated if the evaluation of the responsiveness to therapy by LTA can be replaced by MEA in 160 acute coronary syndrome (ACS) patients on dual antiplatelet therapy with aspirin and prasugrel or ticagrelor (n = 80 each). Cut-off values for high on-treatment residual platelet reactivity (HRPR) in response to adenosine diphosphate (ADP) or arachidonic acid (AA) were defined according to previous studies showing an association of HRPR with the occurrence of adverse ischemic outcomes. ADP- inducible platelet aggregation was 33% and 37% (P = 0.07) by LTA and 19 AU and 20 AU (P = 0.38) by MEA in prasugrel- and ticagrelor-treated patients, respectively. AA- inducible platelet aggregation was 2% and 3% by LTA and 15 AU and 16 AU by MEA, (all P ≥ 0.3) in patients on prasugrel and ticagrelor, respectively. By LTA, HRPR ADP and HRPR AA were seen in 5%/5% and in 4%/ 13% of patients receiving prasugrel- and ticagrelor, respectively. By MEA, HRPR ADP and HRPR AA were seen in 3%/ 25% and 0%/24% of prasugrel- and ticagrelor-treated patients, respectively. ADP-inducible platelet reactivity by MEA correlated significantly with LTA ADP in prasugrel-treated patients (r = 0.4, P < 0.001), but not in those receiving ticagrelor (r = 0.09, P = 0.45). AA-inducible platelet aggregation by LTA and MEA did not correlate in prasugrel- and ticagrelor-treated patients. Sensitivity/specificity of HRPR by MEA to detect HRPR by LTA were 25%/99% for MEA ADP and 100%/79% for MEA AA in prasugrel-treated patients, and 0%/100% for MEA ADP and 70%/83% for MEA AA in ticagrelor-treated patients. In conclusion, on-treatment residual ADP-inducible platelet reactivity by LTA and MEA shows a significant correlation in prasugrel- but not ticagrelor-treated patients. However, in both groups LTA and MEA revealed heterogeneous results regarding the classification of patients as responders or non-responders to P2Y₁₂ inhibition.

Ticagrelor Inhibits Toll-Like and Protease-Activated Receptor Mediated Platelet Activation in Acute Coronary Syndromes

Purpose

Since ticagrelor inhibits the cellular uptake of adenosine, thereby increasing extracellular adenosine concentration and biological activity, we hypothesized that ticagrelor has adenosine-dependent antiplatelet properties. In the current study, we compared the effects of ticagrelor and prasugrel on platelet activation in acute coronary syndrome (ACS).

Methods

Platelet surface expression of P-selectin and activated glycoprotein (GP) IIb/IIIa in response to adenosine diphosphate (ADP), the toll-like receptor (TLR)-1/2 agonist Pam3CSK4, the TLR-4 agonist lipopolysaccharide (LPS), the protease-activated receptor (PAR)-1 agonist SFLLRN, and the PAR-4 agonist AYPGKF were measured by flow cytometry in blood from 80 ticagrelor- and 80 prasugrel-treated ACS patients on day 3 after percutaneous coronary intervention. Residual platelet aggregation to arachidonic acid (AA) and ADP were assessed by multiple electrode aggregometry and light transmission aggregometry.

Results

ADP-induced platelet activation and aggregation, and AA-induced platelet aggregation were similar in patients on ticagrelor and prasugrel, respectively (all p ≥ 0.3). Further, LPS-induced platelet surface expression of P-selectin and activated GPIIb/IIIa did not differ significantly between ticagrelor- and prasugrel-treated patients (both p > 0.4). In contrast, Pam3CSK4-induced platelet surface expression of P-selectin and activated GPIIb/IIIa were significantly lower in ticagrelor-treated patients (both p ≤ 0.005). Moreover, SFLLRN-induced platelet surface expression of P-selectin and activated GPIIb/IIIa were significantly less pronounced in patients on ticagrelor therapy compared to prasugrel-treated patients (both p < 0.03). Finally, PAR-4 mediated platelet activation as assessed by platelet surface expression of activated GPIIb/IIIa following stimulation with AYPGKF was significantly lower in patients receiving ticagrelor (p = 0.02).

Conclusion

Ticagrelor inhibits TLR-1/2 and PAR mediated platelet activation in ACS patients more strongly than prasugrel.

Mean Corpuscular Volume Predicts Adverse Outcomes Following Peripheral Angioplasty With Stenting and Is Associated With On-Treatment Platelet Reactivity

Structural aspects of red blood cells have been associated with cardiovascular disease. No data linking mean corpuscular volume (MCV) to clinical outcomes and on-treatment platelet reactivity in patients with peripheral artery disease (PAD) are available. We investigated a composite of atherothrombotic events and target vessel restenosis or reocclusion following infrainguinal stenting for stable PAD. Residual platelet reactivity was measured by light transmission aggregometry (LTA) and the VerifyNow assays. We included 104 patients receiving dual antiplatelet therapy (DAPT) with aspirin and clopidogrel. In receiver-operating characteristic analysis, MCV effectively discriminated between patients with and without adverse outcomes and identified a MCV ≤90.8 fL as optimal cutoff. Adverse outcomes occurred significantly more often in patients with low MCV (log-rank P = .002). In univariable Cox regression analysis, low MCV was associated with an increased risk of future adverse outcomes (hazard ratio [HR]: 2.662 [95%CI: 1.304-5.434]; P = .007) and remained significantly associated after adjustment (HR: 2.591 [95%CI: 1.242-5.403]; P = .011). Mean corpuscular volume was inversely correlated with arachidonic acid (AA)- and adenosine diphosphate (ADP)-inducible platelet reactivity by LTA and with the VerifyNow aspirin assay. Low MCV is associated with adverse outcomes over 2 years following infrainguinal stenting. Mean corpuscular volume correlates inversely with AA- and ADP-inducible platelet reactivity during DAPT.

Platelet and hemoglobin count at diagnosis are associated with survival in African American and Caucasian patients with colorectal cancer

BACKGROUND

African Americans (AAs) compared to Caucasian Americans (CAs) with colorectal cancer (CRC) have lower stage-specific survival. CRC patients often present with several hematopathologies (such as thrombocytosis, thrombocytopenia, anemia) at diagnosis, which is associated with poorer survival. However, whether these measures impact the racial disparity in survival is not known.

METHODS

The study population was composed of 581 histologically confirmed CRCs at the Medical University of South Carolina (393 CA, 188 AA) diagnosed between 01/01/2000 and 06/30/2013. We used Cox proportional hazards regression to estimate the association between thrombocytosis, thrombocytopenia, or anemia at diagnosis and risk of death by race. This analysis was adjusted for age, sex, stage and first-line treatment.

RESULTS

In all patients combined, thrombocytosis, thrombocytopenia, and anemia (vs. the normal ranges) were associated with significantly higher risks of death. In the race-specific analyses, AAs (HR 2.51 [95 % CI: 1.52-4.15]) vs. CAs (HR 1.15 [95 % CI: 0.75-1.75]) with thrombocytosis compared to normal had a higher risk of death (p for difference = 0.03).

CONCLUSIONS

Abnormal thrombocyte and hemoglobin levels at diagnosis were associated with poorer survival. AAs compared to CAs with elevated platelets at diagnosis had a higher risk of death. Our study is the first to examine the role of race, hematologic measures at diagnosis, and risk of death in colorectal cancer patients. These results suggest that the racial differences in the immune response may contribute to the racial disparity in survival.

Protease-activated receptor-mediated platelet aggregation in acute coronary syndrome patients on potent P2Y12 inhibitors

BACKGROUND

Despite the increasing use of potent P2Y12 inhibitors, further atherothrombotic events still impair the prognosis of many acute coronary syndrome (ACS) patients. This may in part be attributable to intact platelet aggregation via the human thrombin receptors protease-activated receptor (PAR)-1 and PAR-4.

OBJECTIVE

We studied PAR mediated platelet aggregation in ACS patients following percutaneous coronary intervention (PCI) with stent implantation in a cross-sectional study.

METHODS

Platelet aggregation to ADP as well as to the PAR-1 agonist SFLLRN and the PAR-4 agonist AYPGKF was assessed by multiple electrode aggregometry in 194 ACS patients on dual antiplatelet therapy with aspirin and either prasugrel (n = 114) or ticagrelor (n = 80) 3 days after PCI.

RESULTS

Based on the consensus cutoff value, high on-treatment residual platelet reactivity to ADP (HRPR ADP) was observed in only 2 prasugrel-treated patients. Both patients with HRPR ADP had also a normal response to SFLLRN and AYPGKF. Among the 112 prasugrel-treated patients with adequate P2Y12 inhibition, 50 patients (45%) still had a normal response to SFLLRN, and 70 patients (63%) still had a normal response to AYPGKF. Among the 80 ticagrelor-treated patients with adequate P2Y12 inhibition, 25 patients (31%) still had a normal response to SFLLRN, and 50 (63%) still had a normal response to AYPGKF.

CONCLUSION

Normal platelet aggregation via PAR-1 and PAR-4 is preserved in many patients with adequate P2Y12 inhibition by prasugrel and ticagrelor. The present findings may at least in part explain adverse ischemic events despite potent P2Y12 inhibition.

Low Levels of High-Density Lipoprotein Cholesterol Are Linked to Impaired Clopidogrel-Mediated Platelet Inhibition

Low high-density lipoprotein cholesterol (HDL-C) levels are an independent predictor of ischemic events in patients with atherosclerotic cardiovascular disease. This may in part be due to decreased clopidogrel-mediated platelet inhibition in patients with low HDL-C. We investigated the association of HDL-C with on-treatment platelet reactivity to adenosine diphosphate (ADP) in 314 patients on dual antiplatelet therapy with clopidogrel and aspirin undergoing angioplasty and stenting. Platelet P-selectin expression was assessed by flow cytometry, and platelet aggregation was determined by the VerifyNow P2Y₁₂ assay and the Impact-R. High-density lipoprotein cholesterol levels were inversely associated with P-selectin expression and the VerifyNow P2Y₁₂ assay (both P ≤ .01). Moreover, we found a positive correlation of HDL-C with surface coverage by the Impact-R ( P = .003). Patients with low HDL-C (≤35 mg/dL) exhibited a significantly higher P-selectin expression in response to ADP and higher platelet aggregation by the VerifyNow P2Y₁₂ assay and the Impact-R than patients with normal HDL-C (>35 mg/dL; all P < .05). High on-treatment residual platelet reactivity by the VerifyNow P2Y₁₂ assay occurred significantly more frequently in patients with low HDL-C levels than in those with normal HDL-C (47.4% vs 30.1%, P = .01). In conclusion, low HDL-C is linked to impaired clopidogrel-mediated platelet inhibition after angioplasty and stenting.