Anamnestic frailty phenotype and adverse outcomes in patients treated with direct oral anticoagulants: Validation and comparative performance with frailty phenotype

AIMS

The anamnestic frailty phenotype (AFP) is a quick, instrument-free tool derived from frailty phenotype (FP). We prospectively evaluated the discriminative capacity and prognostic value of AFP in ambulatory patients receiving DOACs for atrial fibrillation (AF) or venous thromboembolism (VTE), and compared AFP performance with that of FP.

METHODS AND RESULTS

Sensitivity, specificity, positive and negative predictive value (PPV, NPV) with corresponding 95% confidence intervals (95%CI), were estimated for bleeding, thromboembolism, and all-cause mortality. Risk ratios (RRs) were calculated in frail versus non-frail patients. Of 236 patients (median age 78 years), 98 (42%) and 89 (38%) were classified as frail according to FP and AFP, respectively (Kappa= 0.76). Frailty, as assessed by AFP, was associated with higher risk of bleeding (RR 2.3; 95%CI, 1.2 to 4.6), and mortality (RR 4.4; 95%CI, 1.3 to 19.7). Similarly, to FP, AFP exhibited modest sensitivity and specificity, but high NPV that was 91% (95%CI, 85 to 95) for bleeding, 98% (95%CI, 94 to 100) for thromboembolism, and 98% (95%CI, 94 to 100) for mortality.

CONCLUSION

Among patients receiving DOACs for AF or VTE, AFP was associated with an increased risk of adverse outcomes. AFP exhibited modest sensitivity and specificity, but excellent NPV. If confirmed, these findings suggest that AFP may represent a rapid, easy-to-use and unexpensive tool that may potentially help identify patients at lower risk for adverse outcomes and tailor anticoagulation management.

Reduced platelet glycoprotein Ibα shedding accelerates thrombopoiesis and COX-1 recovery: implications for aspirin dosing regimen

Cardiovascular (CV) disease prevention with low-dose aspirin can be less effective in patients with a faster recovery of platelet (PLT) cyclooxygenase (COX)-1 activity during the 24-hour dosing interval. We previously showed that incomplete suppression of TXA2 over 24 hours can be rescued by a twice daily aspirin regimen. Here we show that reduced PLT glycoprotein (GP)Ibα shedding characterizes patients with accelerated COX-1 recovery and may contribute to higher thrombopoietin (TPO) production and higher rates of newly formed PLT, escaping aspirin inhibition over 24 hours. Two hundred aspirin-treated patients with high CV risk (100 with type 2 diabetes mellitus) were stratified according to the kinetics of PLT COX-1 activity recovery during the 10- to 24-hour dosing interval. Whole proteome analysis showed that PLT from patients with accelerated COX-1 recovery were enriched in proteins involved in cell survival, inhibition of apoptosis and cellular protrusion formation. In agreement, we documented increased plasma TPO, megakaryocyte maturation and proplatelet formation, and conversely increased PLT galactose and reduced caspase 3, phosphatidylserine exposure and ADAM17 activation, translating into diminished GPIbα cleavage and glycocalicin (GC) release. Treatment of HepG2 cells with recombinant GC led to a dose-dependent reduction of TPO mRNA in the liver, suggesting that reduced GPIbα ectodomain shedding may unleash thrombopoiesis. A cluster of clinical markers, including younger age, non-alcoholic fatty liver disease, visceral obesity and higher TPO/GC ratio, predicted with significant accuracy the likelihood of faster COX-1 recovery and suboptimal aspirin response. Circulating TPO/GC ratio, reflecting a dysregulation of PLT lifespan and production, may provide a simple tool to identify patients amenable to more frequent aspirin daily dosing.

Direct oral anticoagulant plasma levels in hospitalized COVID-19 patients treated with dexamethasone

Direct oral anticoagulants (DOACs) are not recommended in COVID-19 patients receiving dexamethasone because of potential drug-drug and drug-disease interactions affecting anticoagulant concentration and activity. To evaluate short- and long-term pharmacokinetic interactions, serial through and peak DOAC plasma levels were prospectively measured during and after dexamethasone therapy, as well as during the acute phase and after recovery from COVID-19 in hospitalized, non-critically ill patients undergoing treatment with DOACs. Thirty-three (18 males, mean age 79 years) consecutive patients received DOACs (17 apixaban, 12 rivaroxaban, 4 edoxaban) for atrial fibrillation (n = 22), venous thromboembolism (n = 10), and acute myocardial infarction (n = 1). Twenty-six patients also received dexamethasone at a dose of 6 mg once daily for a median of 14 days. Trough DOAC levels on dexamethasone were within and below expected reference ranges respectively in 87.5 and 8.3% of patients, with no statistically significant differences at 48–72 h and 14–21 days after dexamethasone discontinuation. Peak DOAC levels on dexamethasone were within expected reference ranges in 58.3% of patients, and below ranges in 33.3%, of whom over two thirds had low values also off dexamethasone. No significant differences in DOAC levels were found during hospitalization and after resolution of COVID-19. Overall, 28 patients were discharged alive, and none experienced thrombotic or bleeding events. In this study, dexamethasone administration or acute COVID-19 seemed not to affect DOAC levels in hospitalized, non-critically ill COVID-19 patients.

Effects of body composition on the procoagulant imbalance in obese patients

Obesity is associated with increased thrombotic risk and hypercoagulability whose main driver is an excess of coagulation factor VIII relative to protein C. The aims of this study were to evaluate the association between factor VIII, protein C, factor VIII-to-protein C ratio and bioimpedance parameters of body composition in obese patients. We analysed blood from 69 obese patients and 23 non-obese healthy controls. Plasma levels of factor VIII, protein C, and factor VIII-to-protein C ratio were correlated with total fat, visceral fat, and muscle mass. Compared to controls, obese patients had significantly higher factor VIII (110.5% vs 78.05%, p < 0.001), protein C (120.99% versus 110.51%, p = 0.014), and factor VIII-to-protein C ratio (0.93 versus 0.73, p = 0.002). In obese patients, factor VIII correlated with body-mass index, body fat percentage, muscle mass percentage, and fat-to-muscle ratio, whereas protein C had significant relationships with body fat percentage, muscle mass percentage and fat-to-muscle ratio, but not with body-mass index. Factor VIII-to-protein C ratio > 1 was significantly associated with body-mass index (odds ratio 1.08, 95% CI 1.02 to 1.14) and fat-to-muscle ratio (odds ratio 2.47, 95% CI 1.10 to 5.55). Factor VIII-to-protein C ratio strongly correlated with D-dimer levels in the overall population (rho 0.44, p < 0.001) and obese patients (rho 0.41, p < 0.001). In obese patients, bioimpedance measures of body fat and muscle mass percentage were associated with factor VIII and protein C. Factor VIII-to-protein C ratio was strongly associated with fat-to-muscle ratio and only modestly related to BMI.

A missense mutation W797R in the myophosphorylase gene in a Spanish patient with McArdle's disease

We identified a novel missense mutation in the myophosphorylase gene (PYGM) in a Spanish patient with McArdle's disease. This homozygous T-to-C transition results in the replacement of a highly conserved tryptophan at amino acid position (aa) 797 with an arginine in the C-terminal domain of the PYGM protein. The lack of enzyme activity in the proband's muscle is consistent with a crucial role of the aa 797 in the normal function of the PYGM protein. Our data further expand the genetic heterogeneity in patients with McArdle's disease.