What are the core and bridge symptoms during the vulnerable phase in patients with chronic heart failure?

This invited commentary refers to ‘Exploring symptom clusters and core symptoms during the vulnerable phase in patients with chronic heart failure: a network-based analysis’, by Z. Bian et al., https://doi.org/10.1093/eurjcn/zvae152.

Despite receiving available treatments, patients with chronic heart failure (CHF) remain incredibly vulnerable to a poor post-discharge prognosis.¹ The initial post-discharge period (within 2–3 months) of heart failure hospitalization represents a critical vulnerable phase, which carries a particularly high risk of readmission and mortality, thus necessitating urgent improvements in clinical management.¹ Owing to persistent congestion and poor haemodynamic reserve, patients with CHF in the vulnerable phase continue to endure considerable symptom burdens, which serve as significant harbingers of reduced quality of life and increased adverse clinical events.^1,2 The complexity and interplay of concurrent heart failure symptoms pose substantial challenges for patients and healthcare providers in maintaining effective symptom management. Whilst contemporary research has increasingly paid more attention to symptom clusters in recent years, there remains a lack of in-depth exploration of the interaction mechanism of symptom clusters among patients with CHF in the vulnerable period. Network analysis, an emerging statistical methodology, can comprehensively and quantitatively evaluate the associations among multiple symptoms and facilitate the identification of core symptoms within the symptom network and bridge symptoms between symptom clusters.³ Intervention targeting the core and bridge symptoms may potentially minimize symptom burden and enhance symptom management and prognosis of patients with CHF during the vulnerable phase.

In a recent article published in the European Journal of Cardiovascular Nursing, Bian et al.⁴ recruited 402 patients with CHF within 3 months after discharge to fill in the symptom-related entries of the Minnesota Living with Heart Failure Questionnaire (MLHFQ).⁵ Of the nine heart failure symptoms measured, up to six had a prevalence of exceeding 50%, whereby ‘increased need to rest’ emerged as the most prevalent (95.3%) and severe symptom. Regarding symptom clusters, the emotional-cognitive symptom cluster (including ‘depression’, ‘worry’, ‘sleep difficulties’, and ‘cognitive problems’) and the somatic symptom cluster (including ‘dyspnoea on exertion’, ‘shortness of breath’, ‘fatigue’, ‘increased need of rest’, and ‘oedema’) were identified by exploratory factor analysis.

The key finding of this study centred on the identification of core symptoms using network analysis. These core symptoms, which exhibited the strongest link to other symptoms, play a key role in the network.³ Interventions targeting core symptoms may accelerate the deactivation of the symptom network, with great advantages in precision and efficiency.⁶ Bian et al.⁴ found that the core symptoms were ‘depression’, ‘dyspnoea on exertion’, and ‘worry’ in the symptom network of CHF patients during the vulnerable phase. ‘Depression’ was the most central node of the symptom network, demonstrating the strongest correlation with another valuable core symptom ‘worry’. This reverses the excessive focus on somatic symptoms in conventional thinking, indicating that special attention should be paid to psychological symptoms in patients with CHF in the vulnerable phase. Another important core symptom was ‘dyspnoea on exertion’, which demonstrated a strong correlation with ‘fatigue’ and ‘shortness of breath’ in the symptom network. Bian et al.⁴ proposed a plausible localized cycle of ‘dyspnoea on exertion–fatigue–shortness of breath–dyspnoea on exertion’ and suggested that targeted interventions (e.g. exercise rehabilitation and inspiratory muscle training) might break the cycle and exhibit effectiveness in relieving patients’ symptoms during the vulnerable phase and beyond.

A novel and substantive discovery by Bian et al.⁴ was the identification of bridge symptoms interconnecting two symptom clusters in patients with CHF in the vulnerable phase. Specifically, ‘cognitive problems’ emerged as the strongest bridging symptoms in the symptom network. In conjunction with this finding, two previous studies also revealed cognitive decline in patients after heart failure hospitalization,^7,8 suggesting the necessity to screen cognitive problems and incorporate them into symptom management strategies in patients with CHF during the vulnerable phase. Furthermore, ‘sleep difficulties’ and ‘fatigue’ had important bridging effects on transmitting the emotional-cognitive and somatic symptoms, which deserve more attention as well, especially in elderly and female patients with CHF.^9,10 Interventions focusing on the bridge symptoms may potentially break connectivity between symptom clusters, prevent mutual exacerbation of symptom clusters, and alleviate other symptoms in the network.¹¹ Given the limited information on bridge symptoms in CHF patients during the vulnerable phase, further studies are warranted to validate the findings in this study.

Whilst this study presents certain limitations (e.g. lack of a representative sample), it enhances the understanding of the symptoms experienced by patients with CHF in the vulnerable phase. However, the development and validation of interventions targeting core and bridge symptoms remain imperative. Moreover, further exploration is needed to address the heterogeneity in patients with CHF, the underlying causal relationships between symptoms, and change trends of core and bridge symptoms during the 3-month-long vulnerable period. Studies with personalized network modelling, simulation-based or dynamic network analysis,^12–14 and longitudinal design should be conducted to investigate the underlying mechanisms of multiple symptoms.

Overall, this study identified the core and bridge symptoms in patients with CHF during a critical period of vulnerability, laying the foundation for future research. It is hoped that healthcare providers will view the core and bridge symptoms as intervention focuses and establish a personalized follow-up system during the vulnerable period to improve the timeliness, efficiency, and precision of symptom management, thereby reducing the symptom burden and improving the outcomes of patients with CHF.

Author contributions

Wenjie Fang (Conceptualization [equal], Writing—original draft [equal], Writing—review & editing [supporting]), and Xiuzhen Fan (Conceptualization [equal], Supervision [lead], Writing—original draft [equal], Writing—review & editing [lead])

Funding

None.

Data availability

No new data were generated or analysed in support of this article.

References

Author notes