BNP is the acronym of Brain Natriuretic Peptide (BNP, Cerebral Natriuretic Peptide) or more correctly of the B-type natriuretic peptide (Type B Natriuretic Peptide). The term “Brain” is in fact out of place and refers to the initial discovery of this peptide in pig brain extracts. In fact, in humans, BNP is secreted mainly by the heart’s ventricles in response to excessive stretching of their heart muscle cells, indicating a rise in ventricular volume or end-diastolic pressure within the ventricle itself. The causes are usually due to the following cases:
- reduced myocardial contractility as a fraction of ejection: heart muscle can not contract enough and discharge itself accordingly (infarction, reduced muscle efficiency, degeneration associated with aging, severe ischemic heart disease, congestive heart failure).
- the ventricle can not sufficiently drain when there is high resistance to arterial blood vessels (stenosis), stiffness of the arterial walls.
-
heart valve dysfunctions
The N-Terminal fragment of the B-type Natriuretic Peptide is more stable than the BNP
molecule and is found to be more concentrated in the blood and therefore more easily
measurable. NT-proBNP normally increases with aging; in pathological cases, increases
in patients with left ventricular hypertrophy and heart failure, in edematous pathologies
leading to increased atrial and ventricular pressure (renal failure, liver cirrhosis with
ascites), unstable angina and pulmonary hypertension.
The NT-PROBNP possesses a high negative predictive value especially as regards heart failure
(low risk of false negative). This means that if its values are normal it is possible to
exclude with high probability the presence of ventricular dysfunction. Unfortunately,
the positive predictive value is not so good: this means that NT-PROBNP is only a fairly
accurate indicator of the pathology. The NT-PROBNP values are also related to the severity
of the discomfort and prognosis; This means that the greater the value of NT-PROBNP,
the greater the severity of the disease and the hopes of survival of the patient.
Since NT-PROBNP levels represent a predictor of death and cardiovascular events in
patients without prior diagnosis of cardiopathy, the examination is considered a
possible means of screening for the presence of heart failure. Therefore, it is also
useful to monitor the response to the treatment.