Eiichi Watanabe

INTRODUCTION: Coronary artery and heart valve calcification is a risk factor for cardiovascular death in haemodialysis patients, so calcification prevention should be started as early as possible. Treatment with concomitant calcimimetics and low-dose vitamin D receptor activators (VDRAs) is available, but not enough evidence has been obtained on the efficacy of this regimen, particularly in patients with short dialysis duration. Therefore, this study will evaluate the efficacy and safety of early intervention with upacicalcet, a calcimimetic used to prevent coronary artery calcification in this patient population. METHODS AND ANALYSIS: This multicentre, open-label, randomised, parallel-group controlled study will compare an early intervention group, which received upacicalcet and a low-dose VDRA, with a conventional therapy group, which received a VDRA. The primary endpoint is a change in log coronary artery calcium volume score from baseline to 52 weeks. The main inclusion criteria are as follows: (1) age 18 years or older; (2) dialysis is planned or dialysis duration is less than 60 months; (3) intact parathyroid hormone (PTH) >240 pg/mL or whole PTH level>140 pg/mL; (4) serum-corrected calcium≥8.4 mg/dL and (5) Agatston score >30. The main exclusion criteria are as follows: (1) history of parathyroid intervention or fracture in the past 12 weeks; (2) history of myocardial infarction, stroke or leg amputation in the past 12 weeks; (3) history of coronary angioplasty and (4) heart failure of New York Heart Association class III or worse. ETHICS AND DISSEMINATION: The study will comply with the Declaration of Helsinki and the Japanese Clinical Trials Act. The study protocol has been approved by the Fujita Health University Certified Review Board (file no. CR22-052). Written informed consent will be obtained from all participants. Study results will be presented in academic meetings and peer-reviewed academic journals. TRIAL REGISTRATION NUMBER: jRCTs041220126.

Any reliable biomarker has to be specific, generalizable, and reproducible across individuals and contexts. The exact values of such a biomarker must represent similar health states in different individuals and at different times within the same individual to result in the minimum possible false-positive and false-negative rates. The application of standard cut-off points and risk scores across populations hinges upon the assumption of such generalizability. Such generalizability, in turn, hinges upon this condition that the phenomenon investigated by current statistical methods is ergodic, i.e., its statistical measures converge over individuals and time within the finite limit of observations. However, emerging evidence indicates that biological processes abound with nonergodicity, threatening this generalizability. Here, we present a solution for how to make generalizable inferences by deriving ergodic descriptions of nonergodic phenomena. For this aim, we proposed capturing the origin of ergodicity-breaking in many biological processes: cascade dynamics. To assess our hypotheses, we embraced the challenge of identifying reliable biomarkers for heart disease and stroke, which, despite being the leading cause of death worldwide and decades of research, lacks reliable biomarkers and risk stratification tools. We showed that raw R-R interval data and its common descriptors based on mean and variance are nonergodic and non-specific. On the other hand, the cascade-dynamical descriptors, the Hurst exponent encoding linear temporal correlations, and multifractal nonlinearity encoding nonlinear interactions across scales described the nonergodic heart rate variability more ergodically and were specific. This study inaugurates applying the critical concept of ergodicity in discovering and applying digital biomarkers of health and disease.

Background: We aimed to investigate the association between ventricular repolarization instability and sustained ventricular tachycardia and ventricular fibrillation (VT/VF) occurring within 48 h (acute-phase VT/VF) after the onset of acute coronary syndrome (ACS) and the prognostic role of repolarization instability and heart rate variability (HRV) after discharge from the hospital. Methods: We studied 572 ACS patients with a left ventricular ejection fraction >35%. The ventricular repolarization instability was assessed by the beat-to-beat T-wave amplitude variability (TAV) using high-resolution 24-h Holter ECGs recorded at a median of 11 days from the date of admission. We calculated the HRV parameters including the deceleration capacity (DC) and non-Gaussian index calculated on a 25 s timescale (λ25s). The DC and λ25s were dichotomized based on previous studies' thresholds. Results: Acute-phase VT/VF developed in 43 (7.5%) patients. In-hospital mortality was significantly higher among VT/VF patients (4.7% vs. 0.9%, p =.03). An adjusted logistic model showed that the maximum TAV (odds ratio 1.02, 95% confidence interval [CI] 1.00–1.29, p =.04) was associated with acute-phase VT/VF. During a median follow-up period of 2.1 years, 19 (3.3%) patients had cardiac deaths or resuscitated cardiac arrest. Acute-phase VT/VF (p =.12) and TAV (p =.72) were not significant predictors of survival. An age and sex-adjusted Cox model showed that the DC (p <.01), λ25s (p <.01), and emergency coronary intervention (p <.01) were independent predictors. Conclusion: T-wave amplitude variability was associated with acute-phase VT/VF, but the TAV was not predictive of survival post-discharge. The DC, λ25s, and emergency coronary intervention were independent predictors of survival.