Blunted increase in plasma BNP during acute coronary syndrome attacks in obese patients

Background

Unexpectedly low natriuretic peptide (NP) levels in proportion to heart failure severity are often observed in obese individuals. However, the magnitude of NP elevation in response to acute cardiac stress in obesity has not yet been extensively studied. This study aimed to determine the impact of obesity on the increase in plasma NP in response to cardiac hemodynamic stress during acute coronary syndrome (ACS) attacks.

Methods and Results

The study population included 557 consecutive patients with ACS for whom data were collected during emergency cardiac catheterization. To determine the possible impact of body mass index (BMI) on the relationship between left ventricular ejection fraction (LVEF) and plasma B-type NP (BNP) levels, the study population was divided into two groups (Group 1: BMI <25, Group 2: BMI ≥25 [kg/m²]). Both BMI and LVEF were significantly and negatively correlated with BNP. Although a significant negative correlation between LVEF and BNP was observed in both groups, the regression line of Group 2 was significantly less steep than that of Group 1. Accordingly, BNP/LVEF ratio in Group 2, which indicates the extent of BNP increase in response to LVEF change, was significantly lower than that in Group 1.

Conclusions

Blunted increase in plasma BNP in response to cardiac hemodynamic stress during ACS attacks was observed in obese individuals. In addition to the relatively low plasma BNP levels at baseline in obese individuals, the blunted response of BNP elevation to ACS attacks may have important pathophysiological implications for hemodynamic regulation and myocardial energy metabolism.