Exploring gender differences in trajectories of clinical markers and symptoms after left ventricular assist device implantation

Hitting the (bio)mark Part 2: analysing, interpreting, and reporting biomarker data in cardiovascular research

Incorporating biomarkers into cardiovascular studies, including nursing research, is a common approach when identifying underlying mechanisms and providing targets for intervention. However, effective utilization of biomarker data demands careful consideration. In the analysis, interpretation, and reporting phase, there are many facets to consider, including non-normality of the data, normalization procedures, and potential confounding influences of other clinical data. Furthermore, as many studies focus on patient-reported outcomes (PROs), it is important that the analysis and interpretation of biomarkers in relation to PROs is rigorous and reproducible. In this article, Part 2 of 2, we provide an overview of considerations for the analysis, interpretation, and reporting phases of biomarker studies. We also provide an example of these steps.

Hitting the (bio)mark part 1: selecting and measuring biomarkers in cardiovascular research

Cardiovascular studies, including nursing research, frequently integrate biomarkers for diagnostic, prognostic, monitoring, and therapeutic insights. However, effective utilization of biomarker data demands careful consideration. In the study design phase, researchers must select biomarkers that align with study objectives while considering resources and logistical factors. Additionally, a nuanced understanding of disease pathophysiology and biomarker characteristics is needed. During data collection, suitable experimental conditions and assays need to be defined. Whether researchers opt to manage these steps internally or outsource some, a comprehensive understanding of biomarker selection and experiments remains crucial. In this article, part 1 of 2, we provide an overview of considerations for the design to measurement phases of biomarker studies.

Sympathetic dysfunction is associated with worse fatigue and early and subtle symptoms in heart failure: an exploratory sex-stratified analysis

AIMS

Physical symptoms impact patients with heart failure (HF) despite treatment advancements; however, our understanding of the pathogenic mechanisms underlying HF symptoms remains limited, including sex differences therein. The objective of this study was to quantify associations between sympathetic markers [norepinephrine (NE) and 3,4-dihydroxyphenylglycol (DHPG)] and physical symptoms in patients with HF and to explore sex differences in these associations.

METHODS AND RESULTS

We performed a secondary analysis of combined data from two studies: outpatients with HF (n = 111), and patients prior to left ventricular assist device implantation (n = 38). Physical symptoms were measured with the Heart Failure Somatic Perception Scale (HFSPS) dyspnoea and early/subtle symptom subscales and the Functional Assessment in Chronic Illness Therapy Fatigue Scale (FACIT-F) to capture dyspnoea, early symptoms of decompensation, and fatigue. Norepinephrine and DHPG were measured with high-performance liquid chromatography with electrochemical detection. Multivariate linear regression was used to quantify associations between symptoms and sympathetic markers. The sample (n = 149) was 60.8 ± 15.7 years, 41% women, and 71% non-ischaemic aetiology. Increased plasma NE and NE:DHPG ratio were associated with worse FACIT-F scores (P = 0.043 and P = 0.013, respectively). Increased plasma NE:DHPG ratio was associated with worse HFSPS early/subtle symptoms (P = 0.025). In sex-stratified analyses, increased NE:DHPG ratio was associated with worse FACIT-F scores (P = 0.011) and HFSPS early/subtle scores (P = 0.022) among women but not men.

CONCLUSION

In patients with HF, sympathetic dysfunction is associated with worse fatigue and early/subtle physical symptoms with associations stronger in women than men.

Incorporating reproductive system history data into cardiovascular nursing research to advance women's health

The lack of sex-specific variables, such as reproductive system history (RSH), in cardiovascular research studies is a missed opportunity to address the cardiovascular disease (CVD) burden, especially among women who face sex-specific risks of developing CVD. Collecting RSH data from women enrolled in research studies is an important step towards improving women's cardiovascular health. In this paper, we describe two approaches to collecting RSH in CVD research: extracting RSH from the medical record and participant self-report of RSH. We provide specific examples from our own research and address common data management and statistical analysis problems when dealing with RSH data in research.

Soluble Suppression of Tumorigenicity-2 Predicts Mortality and Right Heart Failure in Patients With a Left Ventricular Assist Device

BACKGROUND

Soluble suppression of tumorigenicity-2 (sST2) predicts mortality in patients with heart failure. The predictive value of sST2 in patients with a left ventricular assist device remains unknown. Therefore, we studied the relationship between sST2 and outcome after left ventricular assist device implantation.

METHODS AND RESULTS

sST2 levels of patients with a left ventricular assist device implanted between January 2015 and December 2022 were included in this observational study. The median follow-up was 25 months, during which 1573 postoperative sST2 levels were measured in 199 patients, with a median of 29 ng/mL. Survival of patients with normal and elevated preoperative levels was compared using Kaplan-Meier analysis, which did not differ significantly (P=0.22) between both groups. The relationship between postoperative sST2, survival, and right heart failure was evaluated using a joint model, which showed a significant relationship between the absolute sST2 level and mortality, with a hazard ratio (HR) of 1.20 (95% CI, 1.10-1.130; P<0.01) and an HR of 1.22 (95% CI, 1.07-1.39; P=0.01) for right heart failure, both per 10-unit sST2 increase. The sST2 instantaneous change was not predictive for survival or right heart failure (P=0.99 and P=0.94, respectively). Multivariate joint model analysis showed a significant relationship between sST2 with mortality adjusted for NT-proBNP (N-terminal pro-B-type natriuretic peptide), with an HR of 1.19 (95% CI, 1.00-1.42; P=0.05), whereas the HR of right heart failure was not significant (1.22 [95% CI, 0.94-1.59]; P=0.14), both per 10-unit sST2 increase.

CONCLUSIONS

Time-dependent postoperative sST2 predicts all-cause mortality after left ventricular assist device implantation after adjustment for NT-proBNP. Future research is warranted into possible target interventions and the optimal monitoring frequency.

A Primer on Incorporating Sex as a Biological Variable into the Conduct and Reporting of Basic and Clinical Research Studies

The recent move to require sex as a biological variable (SABV), which includes gender, into the reporting of research published by the American Journal of Physiology - Heart and Circulatory Physiology follows a growing, and much-needed, trend by journals. Understandably, there is concern over how to do this without adding considerable work, especially if one's primary research focus is not on elucidating sex/gender differences. The purpose of this article is to provide additional guidance and examples on how to incorporate SABV into the conduct and reporting of basic and clinical research. Using examples from our research, which includes both studies focused and not focused on sex/gender differences, we offer suggestions for how to incorporate SABV into basic and clinical research studies.