Relationship between B-type natriuretic peptide levels and echocardiographic indices of left ventricular filling pressures in post-cardiac surgery patients.
BACKGROUND
B-type natriuretic peptide (BNP) is increased in post-cardiac surgery patients, however the mechanisms underlying BNP release are still unclear. In the current study, we aimed to assess the relationship between postoperative BNP levels and left ventricular filling pressures in post-cardiac surgery patients.


METHODS
We prospectively enrolled 134 consecutive patients referred to our Center 8 +/- 5 days after cardiac surgery. BNP was sampled at hospital admission and related to the following echocardiographic parameters: left ventricular (LV) diastolic volume (DV), LV systolic volume (SV), LV ejection fraction (EF), LV mass, relative wall thickness (RWT), indexed left atrial volume (iLAV), mitral inflow E/A ratio, mitral E wave deceleration time (DT), ratio of the transmitral E wave to the Doppler tissue early mitral annulus velocity (E/E').


RESULTS
A total of 124 patients had both BNP and echocardiographic data. The BNP values were significantly elevated (mean 353 +/- 356 pg/ml), with normal value in only 17 patients (13.7%). Mean LVEF was 59 +/- 10% (LVEF >or=50% in 108 pts). There was no relationship between BNP and LVEF (p = 0.11), LVDV (p = 0.88), LVSV (p = 0.50), E/A (p = 0.77), DT (p = 0.33) or RWT (p = 0.50). In contrast, BNP was directly related to E/E' (p < 0.001), LV mass (p = 0.006) and iLAV (p = 0.026). At multivariable regression analysis, age and E/E' were the only independent predictors of BNP levels.


CONCLUSIONS
In post-cardiac surgery patients with overall preserved LV systolic function, the significant increase in BNP levels is related to E/E', an echocardiographic parameter of elevated LV filling pressures which indicates left atrial pressure as a major determinant in BNP release in this clinical setting.
Institute of Cardiac Science, Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates. asalustri@skmc.gov.ae
Alessandro
A
Salustri
Elena
E
Cerquetani
Mara
M
Piccoli
Guglielmo
G
Pastena
Alfredo
A
Posteraro
Elisabetta
E
Amici
Salvatore
S
La Carrubba
Sherif
S
Bakir
Wael Abdulrahman
WA
Al Mahmeed
D000368:Aged; D006348:Cardiac Surgical Procedures; D004452:Echocardiography; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D016277:Ventricular Function, Left; D017725:Ventricular Pressure
D020097:Natriuretic Peptide, Brain