Multiscale entropy (MSE) was proposed to characterize complexity as a function of the time-scale factor tau. Despite its broad use, this technique suffers from two limitations: 1) the artificial MSE reduction due to the coarse graining procedure and 2) the introduction of spurious MSE oscillations due to the suboptimal procedure for the elimination of the fast temporal scales. We propose a refined MSE (RMSE), and we apply it to simulations and to 24-h Holter recordings of heart rate variability (HRV) obtained from healthy and aortic stenosis (AS) groups. The study showed that the refinement relevant to the elimination of the fast temporal scales was more helpful at short scales (spanning the range of short-term HRV oscillations), while that relevant to the procedure of coarse graining was more useful at large scales. In healthy subjects, during daytime, RMSE was smaller at short scales (i.e., tau = 1-2) and larger at longer scales (i.e., tau = 4-20) than during nighttime. In AS population, RMSE was smaller during daytime both at short and long time scales (i.e., tau = 1 -11) than during nighttime. RMSE was larger in healthy group than in AS population during both daytime (i.e., tau = 2 -9) and nighttime (i.e., tau = 2). RMSE overcomes two limitations of MSE and confirms the complementary information that can be derived by observing complexity as a function of the temporal scale.

A b s t r a c t Background and aim:Several studies have reported that elevated red cell distribution width (RDW) is associated with poor outcomes in patients with coronary artery disease, chronic heart failure and aortic stenosis following transcatheter aortic valve replacement. Their prognostic utility in patients undergoing aortic valve replacement (AVR) surgery is unknown. Methods:We prospectively evaluated the prognostic value of RDW in a group of 191 consecutive patients with severe symptomatic aortic stenosis undergoing AVR. The pre-defined primary endpoint at the 30-day follow-up was composed of: all cause mortality, perioperative myocardial infarction, perioperative renal failure, prolonged mechanical ventilation, stroke, heart failure, successfully resuscitated cardiac arrest, the occurrence of multiple-organ failure, and the need for additional surgery for any reason. The secondary endpoint was total mortality. In multivariate analysis, RDW (OR 3.274;; p = 0.0003) and RBC (OR 0.373; 95% CI 0.176-0.787; p = 0.0097) remained independent predictors of the composite endpoint. Receiver operating characteristic analysis determined a cut-off value of RDW for the prediction of the occurrence of the combined endpoint at 14.1%. Conclusions:Elevated RDW is associated with a worse outcome following AVR, independent of RBC.

IntroductionDual antiplatelet therapy (DAPT) – aspirin and clopidogrel – is recommended after transcatheter aortic valve implantation (TAVI) without an evidence base. The main aim of the study was to estimate the impact of antithrombotic therapy on early and late bleeding. Moreover, we assessed the impact of patients’ characteristics on early bleeding and the influence of bleeding on prognosis.Material and methodsBetween 2009 and 2011, 83 consecutive TAVI patients, age 81.1 ±7.2 years, were included. Bleeding complications were defined by the Valve Academic Research Consortium (VARC) scale. The median follow-up was 12 ±15.5 months (range: 1 to 23) and included 68 (81.9%) patients.ResultsEarly bleeding occurred in 51 (61.4%) patients. Vitamin K antagonists (VKA) pre-TAVI (p = 0.001) and VKA + clopidogrel early post-TAVI (p = 0.04) were the safest therapies; in comparison to the safest one, peri-procedural DAPT (p = 0.002; p = 0.05) or triple anticoagulant therapy (TAT) (p = 0.003, p = 0.05) increased the risk for early bleeding. Predictors for early bleeding were: clopidogrel pre-TAVI (OR: 4.43, 95% CI: 1.02–19.24, p = 0.04), preceding percutaneous coronary intervention (PCI) (10.08, OR: 95% CI: 1.12–90.56, p = 0.04), anemia (OR: 4.00, 95% CI: 1.32–12.15, p = 0.01), age > 85 years (OR: 5.96, 95% CI: 1.47–24.13, p = 0.01), body mass index (BMI) (OR: 0.86, 95% CI: 0.74–0.99, p = 0.04). Late bleeding occurred in 35 patients (51.4%) on combined therapy, and none on VKA or clopidogrel monotherapy (p = 0.04). Bleeding complications did not worsen the survival.ConclusionsThis study seems to suggest that advanced age, BMI, and a history of anemia increased the risk for early bleeding after TAVI. Clopidogrel pre-TAVI should be avoided; therefore, time of preceding PCI should take into account discontinuation of clopidogrel in the pre-TAVI period. Vitamin K antagonists with clopidogrel seems to be the safest therapy in the early post-TAVI period, similarly as VKA/clopidogrel monotherapy in long-term prophylaxis.

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