Background 

Heart failure affects 26 million people globally[1] and is the most common cause of hospitalization in patients over 65, with an admission rate of 80% for heart failure patients who present to the Emergency Department (ED)[2]. A cross-sectional study between 2005-2012 in Hong Kong found that heart failure accounted for 20,000 related hospitalizations annually, and the hospitalization rate was 0.59 per 1,000.[3] On the other hand, some studies suggested that up to 50% of patients with acute heart failure in the ED may not require hospital admission.[4, 5] Traditionally, emergency physicians relied solely on one's clinical judgment to decide if the patient required hospital admission or outpatient management, which sometimes resulted in admitting low-risk patients to the hospital while discharging high-risk patients.

Over the past two decades, multiple risk stratification instruments have been developed. The goal is to stratify low-risk patients for outpatient care and high-risk patients for admission. Several clinical prediction rules have been validated internally or externally, including Emergency Heart failure Mortality Risk Grade (EHMRG7), Improving Heart Failure Risk Stratification in the Emergency Department (STRATIFY), Acute Heart Failure Risk Score (AHFRS) and Multiple Estimation of risk based on Emergency department (MESSI-AHF).[6, 7, 8, 9] However, the application complexity and the study design limitations have yet to encourage the widespread usage of these rules.[4] For instance, the MESSI-AHF incorporates 13 clinical variables, including the Barthel Index, not routinely obtained in ED consultations. A high proportion of patients with preserved ejection fraction (HFpEF) recruited in their cohort typically have better outcomes.[2]

Latest evidence and models

A large-scale multi-centre prospective validation study published in 2019 provided a breakthrough, rekindling interest in this treatment paradigm. The research team led by Lee DS et al. investigated using EHMRG7 and EHMRG30-ST in mortality prediction. EHMRG7 predicts 7-day mortality, using the parameters included: age, arrival by ambulance, triage systolic blood pressure, heart rate, oxygen saturation, serum potassium level, serum creatinine level, troponin level, presence of active cancer, and the prior use of metolazone. EHMRG30-ST incorporates all components of the EHMRG7 as well as the presence of ST-depression on the 12-lead ECG. The study also compared the accuracy of risk estimation between physicians' clinical judgement and clinical prediction rules. This prospective cohort was more representative than prior studies, which recruited patients with a median age of 81 and more medical comorbidities. For both EHMRG7 and EMHRG30-ST, patients in the very-low-risk or low-risk categories had 7-day and 30-day mortality rates of 0%. Using the EHMRG model, the area under the receiver operating characteristic curve was 0.81.[10] Nevertheless, a reasonable risk stratification tool may inform the clinician of the risk of mortality of an acute heart failure patient, but it does not guide the clinician to take measures that can improve patient outcomes. To complicate matters further, even low-risk patients could have adverse events, including 18% ED revisits and 11% rehospitalization at 30 days.[11] 

During the vulnerable period of discharge, without early aggressive treatment and transitional care in the form of early outpatient follow-up and cardiologist intervention, there is a high risk of ED reattendance and ultimate hospitalization, rendering all previous gains in improving patient care and relieving the healthcare burden lost.[12] The Comparison of Outcomes and Access to Care for Heart Failure (COACH) trial is a stepped-wedge, cluster-randomized trial conducted in Canada to address this problem. The intervention is a system-based strategy, which consists of two aspects: risk stratification and rapid transitional care. For the first part, the EHMRG30-ST score was employed to identify patients at low risk or low-intermediate risk suitable for early discharge. For the second part, early discharged patients were given access to standardized transitional care in the Rapid Ambulatory Program for Investigation and Diagnosis of Heart Failure (RAPID-HF) clinic. At the RAPID-HF clinic, patients were assessed by a nurse-clinician, cardiologist, or a heart failure specialist within 2-3 days, including medication titration, routine bloodwork, echocardiography and other specific cardiac tests. At the end of the 30-day transition period, patients were followed up by a cardiologist or a family physician. This trial recruited 5,452 patients, and the results showed that the intervention group had a lower rate of 30-day rehospitalization for cardiovascular causes (8.1 versus 10.6%; adjusted HR 0.88, 95% CI 0.78-0.99) and all-cause mortality (5.9 versus 6.6%; adjusted HR 0.94, 95% CI 0.74-1.19).[13,14]

Application in Hong Kong 

How about implementation in Hong Kong? Rapidly developing Emergency Medicine Wards (EMW) and Early Ambulatory Care (EAC) can enhance the outpatient management of low-risk heart failure patients as stratified by these clinical decision rules. However, developing hurdles are yet to be solved, including the availability of the heart failure biomarker NT-ProBNP and cardiology assessment in transitional care. Lastly, these clinical decision rules have not been validated in Hong Kong or other Asian countries. 

Conclusion 

Heart failure is a significant clinical burden, and EDs play a pivotal role in streamlining patient care. The use of a systems-based strategy has the potential to reduce hospitalizations and improve patient outcomes. At Prince of Wales Hospital, a fast-track clinical service specialized for heart failure commenced in October 2022 to provide cardiology support, including formal echocardiography, NT-ProBNP and early cardiology follow-up. Case recruitment and auditing of patient outcomes are on their way, and we eagerly await validation studies coming soon. Hopefully, this will be the first of many steps in revolutionizing the management of heart failure patients in the ED.