We have proposed that the blood concentration of BNP in a patient who is admitted with decompensated heart failure comprises two components: a baseline, euvolemic, "dry" BNP level and a BNP level occurring from acute pressure or volume overload ("wet" BNP). At the point of decompensation, the sum of baseline BNP plus the additional production of BNP from ventricular stress owing to acute volume overload will determine the plasma concentration of BNP (Fig. 13).
The lower the "dry" BNP level, the less likely that the patient will require early rehos-pitalization. A low level of BNP (<200-300 pg/mL) correlates with NYHA functional class II and is indicative of a patient who is more likely to be in a true euvolemic state. Knowing a patient's baseline level of BNP at dry weight is likely to be useful in moni-
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Fig. 13. Illustration of potential contribution of volume overload to measured levels of BNP. See text for details.
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