Prasugrel 5 mg inhibits platelet P-selectin and GPIIb–IIIa expression in very elderly and non elderly: results from the GENERATIONS trial, a pharmacodynamic study in stable CAD patients

Antithrombotic strategies in elderly patients with acute coronary syndrome

Elderly patients represent a growing proportion of the acute coronary syndrome population in Western countries. However, their frequent atypical symptoms at presentation often lead to delays in management and to misdiagnosis. Furthermore, their prognosis is poorer than that of younger patients because of physiological changes in platelet function, haemostasis and fibrinolysis, but also a higher proportion of comorbidities and frailty, both of which increase the risk of recurrent thrombotic and bleeding events. This complex situation, with ischaemic and haemorrhagic risk factors often being intertwined, may lead to confusion about the required treatment strategy, sometimes resulting in inadequate management or even to therapeutic nihilism. It is therefore critical to provide a comprehensive overview of our understanding of the pathophysiological processes underlying acute coronary syndrome in elderly patients, and to summarise the results from the latest clinical trials to help decision making for these high-risk patients.

Platelet hyperactivation in multiple myeloma is also evident in patients with premalignant monoclonal gammopathy of undetermined significance

Thrombotic events are common in patients with multiple myeloma (MM), smouldering myeloma (SM) and monoclonal gammopathy of undetermined significance (MGUS). Previous studies have indicated platelet hyperactivation as a feature of thrombotic risk in MM, but there is a dearth of data in MGUS. In the present study, multiparameter analysis of platelet activation and responsiveness was investigated by flow cytometry in patients with MGUS, SM/MM and healthy controls (HCs). The median platelet surface CD63 levels, annexin V and PAC-1 antibody (specific for activated integrin αIIbβ3) binding were significantly elevated in patients with MGUS versus the HCs. These markers were also elevated in SM/MM, but not significantly. In all, 74% of MGUS and 38% of SM/MM patients had one or more elevated marker of platelet activation, compared to 19% of the HCs. Marker-specific hyporesponsiveness of platelets to agonist [adenosine diphosphate (ADP), thrombin receptor-activating peptide 6] stimulation in vitro was observed, with significantly reduced surface levels of P-selectin in response to ADP in patients with MGUS. Platelet-leucocyte aggregates were not altered in patients, while platelet-associated immunoglobulins were elevated in a subset of patients. Overall, we found that platelet hyperactivation is prevalent in both MGUS and SM/MM patients and is potentially related to hyporesponsiveness. These observations suggest that further investigation of the predictive and prognostic value of platelet hyperactivation in such patients is warranted.

Increased Soluble VCAM-1 and Normal P-Selectin in Cystic Fibrosis: a Cross-Sectional Study

Purpose

As life expectancy in cystic fibrosis (CF) increases, questions regarding its potential impact on cardiovascular health arise. Soluble vascular cell adhesion molecule 1 (sVCAM-1), P-selectin (sP-selectin) are proposed as biomarkers of cardiovascular disease. We aimed to: compare their concentrations in clinically stable CF patients and healthy subjects (HS) and verify whether they independently correlate with CF characteristics.

Methods

Serum sVCAM-1 and sP-selectin levels were measured using ELISA. CF was characterized using: forced expiratory volume in 1 s, exocrine pancreatic and CF-related liver disease status, Pseudomonas aeruginosa colonization, serum high-sensitivity C-reactive protein, and body mass index (BMI). CFTR genotypes were classified as severe (classes I and II) or other.

Results

108 CF patients and 51 healthy subjects volunteered for the study. In the CF group BMI was lower (median [IQR]: 20.5 kg/m² [18.4–22.2] vs. 21.6 kg/m² [19.9–23.4], p = 0.02) and hsCRP levels were higher (3.6 mg/L [1.1–7.1] vs. 0.5 mg/dL [0.3–1.0], p < 10⁻¹⁰). While sVCAM-1 concentrations were greater in CF patients (1018 ng/mL [851–1279] vs. 861 ng/mL [806–979], p < 10⁻⁴), sP-selectin levels did not differ (155 ng/mL [129–188] vs. 156 ng/mL [144–177], p = 0.48). None of the multivariable regression models was valid for the prediction of sVCAM-1 and sP-selectin in CF.

Conclusions

We found higher sVCAM-1 concentrations in CF patients than in healthy subjects, which were not explained by CF characteristics. Further research is required to check whether sVCAM-1 is a marker of microangiopathy in CF.

The Rationale for and Clinical Pharmacology of Prasugrel 5 mg

Prasugrel is a third-generation thienopyridine platelet P2Y₁₂ adenosine diphosphate (ADP) receptor antagonist administered with aspirin for the treatment of patients with acute coronary syndrome (ACS) with planned percutaneous coronary intervention. Prasugrel is administered periprocedurally at an oral loading dose of 60 mg followed by daily maintenance doses (MDs) of 10 mg for most patients and 5 mg for patients weighing <60 kg or aged ≥75 years. Data from a prasugrel phase III study, TRITON-TIMI 38, suggested that a lower MD might be more suitable for patients weighing <60 kg or aged ≥75 years; subsequent pharmacokinetic and pharmacodynamic studies have indicated that prasugrel 5 mg reduced platelet reactivity in these populations to an extent similar to that of prasugrel 10 mg in heavier or younger patients. Clinical experience with prasugrel 5 mg is limited, and additional studies are needed to verify the clinical efficacy and safety of this dose in these challenging populations.