Prevalence of Acute Heart Failure and The Role of N-Terminal Prohormone Brain Natriuretic Peptide among Acute Dyspnoeic Patients in the Emergency Room.

Abstract

Background: Acute dyspnoea (AD) is one of the most common presentations in the emergency room (ER). Its myriads of confusing differentials which include acute heart failure (AHF) has significant mortality and morbidity, and specific mode of treatment. The measurement of NT-proBNP among AD patients when AHF is being suspected will aid early diagnosis, treatment and improve outcomes.

Objective: To estimate the prevalence of AHF and usefulness of NT-proBNP among AD patients at the Ekiti State University Teaching Hospital's (EKSUTH) ER.

Method: This was a cross-sectional study. Persons aged 18 years or older with AD in the ER of the EKSUTH, Nigeria were recruited. The patients were sub-categorized into heart failure as a cause of AD (HFAD) and non-heart failure as a cause of AD (nHFAD). NT-proBNP was assayed alongside ECHO parameters for the participants.

Results: There were 143 cases and 72 matched controls. The mean age of patients was 56.96± 13.5yrs while that of the controls was 56.17± 14.5yrs (p=0.685). Seventy-seven patients (54%) had AHF while the remaining 46% were dyspnoea of non-cardiac origin. Pneumonia, COPD, asthma and PE accounted for 33.57%, 8.40%, 2.80% and 1.40% respectively. The median NT-proBNP level was higher (p<0.001) in the AD patients compared to controls; 592.0 vs 37.50 pg/mL. The median NT-proBNP level was higher in the HFAD group than those with nHFAD and the controls (2885.40 vs. 128.70 and 37.50 pg/mL, P<0.001). NT-proBNP levels inversely and moderately correlated with ejection fraction (EF) (ρ= 0.68, p<0.001). It directly and moderately correlated with HF severity using the NYHA functional classification (ρ=0.50, p=0.017). An age-independent NT-proBNP cut-point level of 305 pg/mL recorded 93.5%, 88.3%, 45.3% and 99.2% for sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) respectively.

Conclusion: AHF is the major cause of AD in ER. In AHF patients, NT-proBNP correlated inversely well with EF and NYHA functional classification, and has high sensitivity and NPV.