Relationship Between B-Type Natriuretic Peptides and Pulmonary Capillary Wedge Pressure in the Intensive Care Unit

• Published in: Journal of the American College of Cardiology Vol. 45; no. 10; pp. 1667 - 1671
• Main Authors: Forfia, Paul R., Watkins, Stanley P., Rame, J. Eduardo, Stewart, Kerry J., Shapiro, Edward P.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 17-05-2005; Elsevier Science; Elsevier Limited
• Subjects: Aged; Biological and medical sciences; Biomarkers - blood; Cardiology; Cardiology. Vascular system; Catheters, Indwelling; Critical Care; Female; Glomerular Filtration Rate - physiology; Heart attacks; Hemodynamics - physiology; Humans; Kidney Function Tests; Male; Medical sciences; Middle Aged; Natriuretic Peptide, Brain - blood; Nerve Tissue Proteins - blood; Peptide Fragments - blood; Peptides; Predictive Value of Tests; Prognosis; Pulmonary Edema - blood; Pulmonary Edema - therapy; Pulmonary Wedge Pressure - physiology; Respiratory distress syndrome; Statistics as Topic; Ventricular Dysfunction, Left - blood; Ventricular Dysfunction, Left - therapy; eGFR; NT-proBNP; PAC; BNP; CI; LVEF; PCWP; ICU; LV; IQR; Brain natriuretic peptide; Pulmonary wedge pressure; Circulatory system; Cardiology; Phlebology; Intensive care unit
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/j.jacc.2005.01.046

We examined whether B-type natriuretic peptides (BNP) can serve as noninvasive markers of pulmonary capillary wedge pressure (PCWP) in the setting of critical illness.
The BNP and N-terminal pro-B-type natriuretic peptide (NT-proBNP) are highly correlated with left ventricular (LV) filling pressures in patients with depressed LV systolic function. However, their relationship to PCWP in a heterogeneous intensive care unit (ICU) population has not been established.
We prospectively studied 40 patients in the ICU requiring invasive hemodynamic monitoring. Hemodynamics were recorded simultaneously with blood sampling for BNP and NT-proBNP.
The BNP (median 420 pg/ml) and NT-proBNP (median 3,304 pg/ml) levels were markedly elevated, but weakly correlated with PCWP (BNP, r = 0.40, NT-proBNP, r = 0.32) and other cardiac parameters. Peptide levels were approximately four-fold greater in patients with impaired (estimated glomerular filtration rate [eGFR] <60 ml/min) versus normal (eGFR >60 ml/min) renal function, despite similar PCWP, cardiac index, and LV ejection fraction. In addition, both BNP and NT-proBNP showed stronger correlations with PCWP in patients with preserved (BNP, r = 0.58, NT-proBNP, r = 0.73) versus impaired renal function (BNP, r = 0.48, NT-proBNP, r = 0.34). Interaction terms between eGFR and BNP (p = 0.06) and NT-proBNP (p = 0.04) suggest that eGFR modulates the relationship of these peptides to filling pressures.
The BNPs are markedly elevated, yet show only weak correlations to PCWP in ICU patients requiring invasive hemodynamic monitoring. Thus, a single value for BNP or NT-proBNP may not be a clinically useful noninvasive marker of filling pressures in the critically ill patient. This appears to be especially true in patients with impaired renal function.