Prognostic value of NT-pro-BNP for myocardial recovery in peripartum cardiomyopathy

Background Peripartum cardiomyopathy (PPCM) is an important cause of pregnancy-associated heart failure and occurs in women towards the end of pregnancy or within the first five months post-partum. Though PPCM is mostly associated with left ventricular (LV) recovery, many affected women develop chronic heart failure with persistently reduced LV ejection fraction (LVEF). Despite recent advances in the treatment of PPCM, clinical predictors of myocardial recovery remain sparse. Purpose N-terminal pro-brain natriuretic peptide (NT-pro-BNP) is the only clinically established biomarker with diagnostic value in PPCM. However, its prognostic value for LV recovery in PPCM remains uncertain. We aimed to establish whether NT-pro-BNP could serve as a predictor of LV recovery in PPCM, and if so, which levels would help with such risk stratification. Methods Women with PPCM seen at the Cardiomyopathy Clinic at Groote Schuur Hospital were recruited between 2012 and 2018. Clinical details and echocardiographic features were recorded at baseline and follow-up, and NT-pro-BNP was measured at baseline. LV recovery was defined as an LVEF of ≥50% at 12-month follow-up. Results This cohort of 42 women with PPCM had a mean age of 29.3±5.8 years and median parity of 2 (IQR 1–4). Almost half (45.2%) presented with a NYHA functional class III/IV. The median systolic and diastolic blood pressures were 117mmHg (IQR 105–133) and 75mmHg (IQR 68–85) respectively. The median heart was 94bpm (IQR 74–103). At diagnosis, mean LVEF was 31.1±8.4% and LV end-diastolic dimension (EDD) of 59mm (IQR 53–64), which improved to LVEF 44.5%±14.5 (p=0.001) and LVEDD 53.6mm (p=0.007) at 1 year. Median NT-pro-BNP at presentation was 915.8pg/mL (IQR 613.6–2422.5). Patients presenting with sinus tachycardia (heart rate >100 bpm) had significantly higher NT-pro-BNP values (1815 vs. 728pg/mL, p=0.009) at the time of diagnosis. At presentation, NT-pro-BNP tended to correlate with LVEDD (R 0.33, p=0.04) and was inversely correlated with LVEF (R −0.39, p=0.01). Whereas initial LVEDD and LVEF did not predict LV recovery at 1 year, NT-pro-BNP at the time of diagnosis had prognostic significance. Patients without LV recovery had a significantly higher NT-pro-BNP at diagnosis (1694.1pg/mL vs. 613.1pg/mL, p=0.02). As shown in Figure 1, NT-pro-BNP of >900pg/mL was associated with lower probability of LV recovery (OR 0.19 [95% CI 0.05–0.73], p=0.018). Conclusion We show, for the first time, that NT-pro-BNP has a prognostic value for LV recovery in PPCM. NT-pro-BNP may be useful in the risk stratification in PPCM and may be used to recommend more intensive follow-up of patients who have a NT-pro-BNP >900pg/mL at diagnosis. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was supported by the South African Medical Research Council and National Research Foundation of South Africa.