Christian Alcaraz Frederiksen

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.