Predictors of high on-aspirin platelet reactivity in elderly patients with coronary artery disease

Left ventricular-aortic angle is associated with platelet reactivity in patients with aortic stenosis

The impact of aortic stenosis on platelet reactivity is unclear. Previous studies reported contradicting results. The reason for this is unknown. It is known that flow alterations enhance platelet reactivity. A steep left ventricular-aortic angle (LV-AO-angle) is associated with turbulent flow in the aorta ascendens. Therefore, in this study, we hypothesized that LV-AO-angle is associated with platelet reactivity in patients with severe aortic stenosis. We included 289 patients with severe aortic stenosis and performed cardiac computertomography to assess the LV-AO-angle. Platelet function was evaluated by light transmission aggregometry. Platelet reactivity was higher in patients with a steep LV-AO-angle (ADP: <160°: 66.99% ± 20.72% vs. ≥160°: 60.66% ± 19.85%, P  = 0.009; collagen: <160°: 78.67% ± 13.19% vs. ≥160°: 73.85% ± 14.44%, P  = 0.003). Using Spearman correlation, ADP and collagen-induced aggregation was associated with LV-AO-angle (ADP: r  = -0.19, P  = 0.0009, R2  = 0.022; collagen: r  = -0.21, P  = 0.0004, R2  = 0.027). Apart from platelet reactivity, body weight, history of myocardial infarction and other factors were associated with steep LV-AO-angle. However, multivariate cox-regression (including body weight, comorbidities, history of MI and cardiac surgery, kidney function and laboratory parameters) revealed that LV-AO angle was a robust predictor of ADP and collagen-induced platelet aggregation. Steep LV-AO-angle is associated with enhanced platelet reactivity in patients with aortic stenosis. This could be the reason of contradicting results regarding platelet function in patients with aortic stenosis in previous studies. In addition, enhanced platelet reactivity in steep LV-AO-angle aortic stenosis patients might be a promising target in pathogenesis of aortic stenosis.

Plasma Fibrinogen Independently Predicts Hypofibrinolysis in Severe COVID-19

High rates of thrombosis are present in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Deeper insight into the prothrombotic state is essential to provide the best thromboprophylaxis care. Here, we aimed to explore associations among platelet indices, conventional hemostasis parameters, and viscoelastometry data. This pilot study included patients with severe COVID-19 (n = 21) and age-matched controls (n = 21). Each patient received 100 mg aspirin therapy at the time of blood sampling. Total platelet count, high immature platelet fraction (H-IPF), fibrinogen, D-dimer, Activated Partial Thromboplastin Time, von Willebrand factor antigen and von Willebrand factor ristocetin cofactor activity, plasminogen, and alpha2-antiplasmin were measured. To monitor the aspirin therapy, a platelet function test from hirudin anticoagulated whole blood was performed using the ASPI test by Multiplate analyser. High on-aspirin platelet reactivity (n = 8) was defined with an AUC > 40 cut-off value by ASPI tests. In addition, in vitro viscoelastometric tests were carried out using a ClotPro analyser in COVID-associated thromboembolic events (n = 8) (p = 0.071) nor the survival rate (p = 0.854) showed associations with high on-aspirin platelet reactivity status. The platelet count (p = 0.03), all subjects. COVID-19 patients presented with higher levels of inflammatory markers, compared with the controls, along with evidence of hypercoagulability by ClotPro. H-IPF (%) was significantly higher among non-survivors (n = 18) compared to survivors (p = 0.011), and a negative correlation (p = 0.002) was found between H-IPF and plasminogen level in the total population. The platelet count was significantly higher among patients with high on-aspirin platelet reactivity (p = 0.03). Neither the ECA-A10 (p = 0.008), and ECA-MCF (p = 0.016) were significantly higher, while the tPA-CFT (p < 0.001) was significantly lower among patients with high on-aspirin platelet reactivity. However, only fibrinogen proved to be an independent predictor of hypofibrinolysis in severe COVID-19 patients. In conclusion, a faster developing, more solid clot formation was observed in aspirin ‘non-responder’ COVID-19 patients. Therefore, an individually tailored thromboprophylaxis is needed to prevent thrombotic complications, particularly in the hypofibrinolytic cluster.

Ticagrelor prevents tumor metastasis via inhibiting cell proliferation and promoting platelet apoptosis

Tumor cells can activate platelets, which in turn facilitate tumor cell survival and dissemination. Platelets inhibition or blocking platelet-tumor cell interactions has become a strategy to suppress tumor progression. In this study, we investigated the effect of ticagrelor, a new antiplatelet drug, on tumor cell proliferation and metastasis. Our results show that ticagrelor not only inhibits the proliferation, migration, and invasion of B16F10 and Lewis lung carcinoma cells but also induces platelet apoptosis. In addition, we find that apoptosis of the platelet cells is dose dependent. Further, the result of in-vivo experiments proved that ticagrelor treatment decreased the tumor metastasis. The results of this study demonstrate that ticagrelor may be a potential anti-tumor agent for tumor metastasis.

Association between renal function and platelet reactivity during aspirin therapy in elderly patients with atherosclerotic cardiovascular disease

Background

Aspirin is the key treatment in the secondary prevention of atherosclerotic cardiovascular disease. High on-treatment platelet reactivity (HTPR) to aspirin has been reported to partially account for the enhanced risk of thrombotic events. In particular, HTPR has been described more frequently among elderly patients. The aim of this study was to identify the clinical and biological factors associated with HTPR in a real-life elderly population.

Methods

In this retrospective study, elderly patients with atherosclerotic cardiovascular disease on regular aspirin treatment were enrolled. Cardiovascular risk factors, routine biological parameters, comorbidities, and concomitant medications were recorded. The upper quartile of the platelet aggregation rate, determined by light transmission aggregometry with arachidonic acid, was defined as the HTPR group.

Results

A total of 304 patients were included (mean age 77 ± 8 years, 76% men). Patients in the HTPR group were older than the patients in the non-HTPR group (mean age: 79 ± 7 vs. 76 ± 8 years, p = 0.008). Patients with moderately decreased estimated glomerular filtration rate (eGFR) had a higher frequency of HTPR than patients with slightly decreased eGFR or normal eGFR (35.8, 22.5, 12.2%, respectively, p < 0.05). In multivariate analysis, an independent risk factor for HTPR was the eGFR (OR: 0.984, 95% CI: 0.980–0.988, p < 0.001).

Conclusions

Advanced age and decreased eGFR are correlated with poor pharmacodynamic response to aspirin.

Serum uric acid level negatively correlated with the prevalence of clopidogrel low response in patients undergoing antiplatelet treatment with aspirin and clopidogrel

BACKGROUND AND AIMS

It has been reported that elevated serum uric acid (SUA) is related to inflammation and potentially to platelet hyper-reactivity. However, the relationship between elevated SUA and residual platelet reactivity is uncertain in patients on dual antiplatelet treatment (DAPT) with aspirin and clopidogrel.

METHODS AND RESULTS

A cross-sectional cohort study was conducted on 2569 patients undergoing DAPT with aspirin and clopidogrel. Patients' SUA levels, residual platelet aggregation, routine blood tests and clinical characteristics were recorded. The relationship between SUA level and residual platelet aggregation was assessed by correlation analysis, and the relationship between SUA level and the prevalence of clopidogrel low response (CLR) was assessed by multivariate logistic regression analysis. Adenosine diphosphate (ADP) induced platelet aggregation (PL_ADP) was higher in normal-SUA group than that in hyperuricemia group [30(21, 40) % vs. 27(19, 39) %, p = 0.032]. No significant difference was found for arachidonic acid (AA) induced platelet aggregation (PL_AA) between the two groups [4(2, 5) % vs. 3(2, 5) %, p = 0.557]. The correlation between SUA and PL_ADP was statistically significant(r = -0.115, p < 0.001), while that between SUA and PL_AA was non-significant (r = -0.012, p = 0.643). Using the multivariate logistic regression analysis, higher SUA concentration was associated with a decreased risk of clopidogrel low response (CLR) (OR [95%CI] = 0.997 [0.995-0.999], p = 0.001).

CONCLUSION

This is the largest study to date showing that in patients receiving DAPT with aspirin and clopidogrel, SUA is independently and negatively associated with the prevalence of clopidogrel low response.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov Unique Identifier: NCT01955200.

Mean platelet volume and coronary artery disease

PURPOSE OF REVIEW

To critically review the literature describing links between mean platelet volume (MPV) and cardiovascular disease (CVD). We will focus on coronary artery disease (CAD). The MPV is measured routinely as part of a routine blood count.

RECENT FINDINGS

There is accumulating evidence showing that the MPV may predict CVD, as well as outcomes in patients with CAD. There is also evidence linking MPV and comorbidities (e.g. diabetes mellitus and impaired glycaemic control) that are expected in patients with CAD. The effect on MPV of drugs commonly used to treat CAD has not been clarified, but there is some evidence that they may exert a beneficial effect on the MPV. More specifically, the MPV may predict the effect of antiplatelet drugs (e.g. clopidogrel). There is also evidence relating MPV to stroke, atrial fibrillation, coronary artery ectasia and periprocedural outcomes after percutaneous coronary intervention (PCI).

SUMMARY

Measuring the MPV may prove useful in CVD risk assessment in patients with established CAD or at risk of developing CAD. Overall, there is evidence pointing to the role of MPV as a contributor rather than simple marker of CVD.

Aspirin antiplatelet effects are associated with body weight

BACKGROUND

Aspirin is indispensable in secondary prevention of ischemic events. Recently, it was reported that clinical aspirin effects are hampered in patients above 70 kg body weight. It is well known that a plethora of reasons beside obesity is associated with increased platelet reactivity and insufficient aspirin effects (HTPR). However, data regarding an association between pharmacodynamic response to aspirin and body weight are missing.

METHODS

In this pilot study, we included 59 patients from University Hospital Duesseldorf. Impedance aggregometry was used to assess pharmacodynamic response to aspirin.

RESULTS

AA-induced platelet reactivity was significantly higher in patients above 70 kg (<70 kg: 28.27 ± 26.33 vs. >70 kg: 45.93 ± 27.1, p = .035) and correlated well with the bodyweight of patients in this study (r = 0.33, R² = 0.09, p = .016). According to this, insufficient pharmacodynamic response (HTPR) to aspirin was significantly more frequent in patients over 70 kg (<70 kg: 25% vs. >70 kg: 43%, p = .035).

CONCLUSION

Insufficient pharmacodynamic response to aspirin is associated with body weight. This finding may play a role in the impaired clinical efficacy of aspirin in patients >70 kg. An optimal aspirin regime in these patients needs to be evaluated in large scale trials.

Factors Influencing Aspirin Hyporesponsiveness in Elderly Chinese Patients

Background

Aspirin hyporesponsiveness increases the risk of ischemic events. Therefore, it is important to investigate the factors influencing aspirin hyporesponsiveness.

Material/Methods

Patients aged 60 years or older who did not take aspirin before enrollment were included, with aspirin 100 mg/day administered after enrollment. The arachidonic acid-induced platelet aggregation rate (Ara) was measured by light transmission assay to evaluate aspirin responsiveness. Patients with Ara in the upper quartile after taking aspirin were assigned to the aspirin hyporesponsive group (Ara-Q4).

Results

A total of 292 elderly patients were included. The median value of Ara after taking aspirin was 5.87% (interquartile range 3.86–10.04%). Compared with the aspirin non-hyporesponsive group (Ara-Q1-3, Ara ≤10.04%, n=220), the level of uric acid (UA) (341.30 μmol/L vs. 299.10 μmol/L, p=0.027) and the ratios of β-blockers (9.72% vs. 2.27%, p=0.015) and diuretics (6.94% vs. 1.36%, p=0.036) were higher in the aspirin hyporesponsive group (Ara-Q4, Ara >10.04%, n=72). After multivariate adjustment, the results demonstrated baseline Ara (odds ratio [OR]: 1.030, 95% confidence interval [CI]: 1.004–1.056, p=0.021), UA level (OR: 1.003, 95% CI: 1.000–1.006, p=0.038), and β-blockers use (OR: 5.487, 95% CI: 1.515–19.870, p=0.010) were independently and positively associated with aspirin hyporesponsiveness.

Conclusions

This study found that baseline Ara, UA level, and β-blockers use were independently and positively associated with aspirin hyporesponsiveness in elderly Chinese patients, which needs to be validated in large-scale studies.