B-Type Natriuretic Peptides (BNP) and Tissue Doppler E/e' Before and After 4 Weeks Standard Treatment of African Heart Failure Subjects: The ABU-BNP Longitudinal Survey

Background: The study aimed at determining the response of BNP and tissue Doppler (TD) E/e' to standard heart failure (HF) therapy in an African black population as data on these are lacking in Africa. BNP assessment in relation to HF severity and its association with its predictors were also determined. Methods: It was a longitudinal-analytical study with a one month follow-up among 100 HF patients seen at Ahmadu Bello University Teaching Hospital, Zaria-Nigeria. Two-way Repeated Measures ANOVA determined BNP levels before and after treatment according to the HF severity. Wilcoxon-Signed Ranks test determined the difference in BNP and TD E/e' before and after treatment. Pearson's correlation assessed log-transformed BNP's association with its predictors. Results: BNP significantly (p<0.001) rose with increasing severity of HF from 386.6 +/- 186.5 pg/mL to 581.7 +/- 299.0 pg/mL to 805.0 +/- 484.0 pg/mL in the NYHA II-IV HF, respectively, with consequent fall in a similar fashion following treatment. The Median (IQR) BNP levels reduced significantly (p<0.001) from 450 (362.5, 712.5) to 275.0 (225, 375.2) pg/mL with a 38.9% reduction over 4 weeks associated with significant improvement in TD E/e', structural and functional parameters. Ln 10 BNP was significantly (p<0.001) positively correlated to TD E/e' before (r=0.51) and after treatment (r=0.43). Likewise, Ln(10)BNP was significantly (p<0.05) negatively correlated to ejection fraction & fractional shortening before and after treatment. Conclusion: BNP and tissue Doppler can serve as useful tools in the assessment of the effectiveness of African HF treatment and functional capacity over 4 weeks. TD E/e' may be a reliable non-invasive estimate of left ventricular filling pressures and diastolic dysfunction.