Echocardiographic Evaluation of Systolic and Diastolic Function: A Preoperative Study of Correlation with Serum NT-proBNP.

Objective: The authors hypothesized that preoperative N-terminal probrain natriuretic peptide (NT-proBNP) correlates well with longitudinal strain measurements and with Doppler measurements of diastolic function. Design: Prospective observational study. Setting: University teaching hospital. Participants: Forty patients undergoing elective cardiac surgery. Interventions: Aortic valve replacement, coronary artery bypass grafting, or a combination of these procedures. Measurements and Main Results: Plasma NT-proBNP concentration was obtained by analyzing blood samples with a commercially available kit. Left ventricular systolic function was assessed by speckle tracking ultrasound strain measurements and left ventricular diastolic function was assessed by 2 Doppler methods: E/A ratio and E/E′ ratio. Tissue Doppler imaging velocities (E′ and A′) were measured in the basal septum (annular) and pulse-wave Doppler was used to measure mitral in-flow profile (E and A). The correlation between global strain data from the speckle tracking ultrasound measurement and NT-proBNP levels was ρ = 0.35 (p = 0.026). With a cutoff value of −15% in global strain measurements, there was a significant difference in NT-proBNP levels (117 v 57 pg/mL, p = 0.048). E/E′ values correlated with NT-proBNP levels (ρ = 0.46, p = 0.011). With a cutoff of 15 in E/E′ values, there were significant differences in corresponding NT-proBNP levels (33 v 113 pg/mL, p = 0.004). Conclusions: A correlation was found between plasma levels of NT-proBNP and speckle tracking ultrasound strain measurements by an easily employed method applicable in the anesthesia and preoperative settings. In addition, the well-established marker of diastolic function, E/E′, correlated well with NT-proBNP, whereas the E/A ratio failed to show any association. [ABSTRACT FROM AUTHOR]