Influence of Predictive Modeling in Implementing Optimal Heart Failure Therapy

CaMKII and PKA-dependent phosphorylation co-regulate nuclear localization of HDAC4 in adult cardiomyocytes

Nuclear histone deacetylase 4 (HDAC4) represses MEF2-mediated transcription, implicated in the development of heart failure. CaMKII-dependent phosphorylation drives nucleus-to-cytoplasm HDAC4 shuttling, but protein kinase A (PKA) is also linked to HDAC4 translocation. However, the interplay of CaMKII and PKA in regulating adult cardiomyocyte HDAC4 translocation is unclear. Here we sought to determine the interplay of PKA- and CaMKII-dependent HDAC4 phosphorylation and translocation in adult mouse, rabbit and human ventricular myocytes. Confocal imaging and protein analyses revealed that inhibition of CaMKII-but not PKA, PKC or PKD-raised nucleo-to-cytoplasmic HDAC4 fluorescence ratio (F_Nuc/F_Cyto) by ~ 50%, indicating baseline CaMKII activity that limits HDAC4 nuclear localization. Further CaMKII activation (via increased extracellular [Ca²⁺], high pacing frequencies, angiotensin II or overexpression of CaM or CaMKIIδC) led to significant HDAC4 nuclear export. In contrast, PKA activation by isoproterenol or forskolin drove HDAC4 into the nucleus (raising F_Nuc/F_Cyto by > 60%). These PKA-mediated effects were abolished in cells pretreated with PKA inhibitors and in cells expressing mutant HDAC4 in S265/266A mutant. In physiological conditions where both kinases are active, PKA-dependent nuclear accumulation of HDAC4 was predominant in the very early response, while CaMKII-dependent HDAC4 export prevailed upon prolonged stimuli. This orchestrated co-regulation was shifted in failing cardiomyocytes, where CaMKII-dependent effects predominated over PKA-dependent response. Importantly, human cardiomyocytes showed similar CaMKII- and PKA-dependent HDAC4 shifts. Collectively, CaMKII limits nuclear localization of HDAC4, while PKA favors HDAC4 nuclear retention and S265/266 is essential for PKA-mediated regulation. These pathways thus compete in HDAC4 nuclear localization and transcriptional regulation in cardiac signaling.

Predicting High-Risk Patients and High-Risk Outcomes in Heart Failure

Identifying patients with heart failure at high risk for poor outcomes is important for patient care, resource allocation, and process improvement. Although numerous risk models exist to predict mortality, hospitalization, and patient-reported health status, they are infrequently used for several reasons, including modest performance, lack of evidence to support routine clinical use, and barriers to implementation. Artificial intelligence has the potential to enhance the performance of risk prediction models, but has its own limitations and remains unproved.

Clinical utility of N-terminal pro-B-type natriuretic peptide for risk stratification of patients with acute decompensated heart failure. Derivation and validation of the ADHF/NT-proBNP risk score

BACKGROUND

NT-proBNP has been associated with prognosis in acute decompensated heart failure (ADHF). Whether NT-proBNP provides additional prognostic information beyond that obtained from standard clinical variables is uncertain. We sought to assess whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) determination improves risk reclassification of patients with ADHF and to develop and validate a point-based NT-proBNP risk score.

METHODS

This study included 824 patients with ADHF (453 in the derivation cohort, 371 in the validation cohort). We compared two multivariable models predicting 1-year all-cause mortality, including clinical variables and clinical variables plus NT-proBNP. We calculated the net reclassification improvement (NRI) and the integrated discrimination improvement (IDI). Then, we developed and externally validated the NT-proBNP risk score.

RESULTS

One-year mortalities for the derivation and validation cohorts were 28.3% and 23.4%, respectively. Multivariable predictors of mortality included chronic obstructive pulmonary disease, estimated glomerular filtration rate, sodium, hemoglobin, left ventricular ejection fraction, and moderate to severe tricuspid regurgitation. Adding NT-proBNP to the clinical variables only model significantly improved the NRI (0.129; p=0.0027) and the IDI (0.037; p=0.0005). In the derivation cohort, the NT-proBNP risk score had a C index of 0.839 (95% CI: 0.798-0.880) and the Hosmer-Lemeshow statistic was 1.23 (p=0.542), indicating good calibration. In the validation cohort, the risk score had a C index of 0.768 (95% CI: 0.711-0.817); the Hosmer-Lemeshow statistic was 2.76 (p=0.251), after recalibration.

CONCLUSIONS

The NT-proBNP risk score provides clinicians with a contemporary, accurate, easy-to-use, and validated predictive tool. Further validation in other datasets is advisable.

The influence of the culture of care on informal caregivers' experiences

The environment of care can have a profound impact on caregiving experiences of families caring for loved ones with a life-limiting illness. Care is often delivered through disease-specific specialty clinics that are shaped by the illness trajectory. In this study, the following 3 distinct cultures of care were identified: interdisciplinary, provider dominant, and cooperative network. Each of these cultures was found to express unique values and beliefs through 5 key characteristics: acknowledgment of the certainty of death, role of the formal caregiver, perception of the patient system, focus of the patient visit across the trajectory, and continuum of care across the trajectory.

Multivariate risk scores and patient outcomes in advanced heart failure

Significant improvements in survival have occurred for patients with advanced heart failure, with an increasing array of therapeutic options sharing quite varied properties of cost, invasiveness, and impact on life expectancy. Risk models allow patients and providers to achieve a better understanding of prognosis than is possible through unstructured holistic assessment. This article reviews scoring systems for heart failure prognostication in the general sense and in the setting of providing answers to specific clinical queries. Topics addressed include outpatient survival, risk of inpatient and post-discharge mortality, potential changes to clinician decision-making through better understanding of prognosis, and mortality after having a left ventricular assist device placed or receiving an implantable cardiac-defibrillator.