Clinical significance of elevated brain natriuretic peptide

Brain natriuretic peptide is abbreviated as BNP, also known as B-type natriuretic peptide. Brain natriuretic peptide is mainly distributed in our brain, spinal cord, heart and lungs and other tissues, among which the heart contains the highest level of brain natriuretic peptide. In clinical use, brain natriuretic peptide mainly acts on vasodilation, lowering blood pressure, diuresis and sympathetic nerve inhibition. Patients with cardiopulmonary diseases or renal failure will have elevated brain natriuretic peptide levels, so brain natriuretic peptide is also used as an indicator to assess cardiac function.

Physiological effects of BNP

1. Dilate blood vessels:

BNP acts directly on free calcium ions in blood vessels, reducing their concentration. The result is that BNP's vasodilatory effect is independent of endothelial cells. The larger the diameter of the blood vessels, the stronger the reaction, and vice versa. This may be related to receptor density. Moreover, BNP's vasodilatory effect is selective, with different intensities on arteries in different parts.

2. Lowers Blood Pressure:

The antihypertensive effect of BNP, like that of ANP, is also due to the direct vasodilatory effect of BNP, which causes a decrease in cardiac blood volume and thus a decrease in cardiac output.

3. Natriuresis and diuresis:

The natriuretic and diuretic effects of BNP are related to the increase in renal perfusion pressure and glomerular filtration rate, and the decrease in renal tubular reabsorption of sodium and water; it inhibits angiotensin and aldosterone; BNP can inhibit the secretion of aldosterone by the adrenal glands, and can inhibit the secretion of renin, thereby reducing the formation of angiotensin II, reducing the secretion of aldosterone, and thereby increasing the excretion of sodium and water.

4 Inhibit the outgoing impulses of sympathetic nerves:

Its intensity of action is similar to that of ANP, and its mechanism of action is basically the same. It is also involved in the regulation of pressure sensitivity, inhibiting animals from drinking water and consuming salt, and acting as a central natriuretic and diuretic.

The role of BNP in cardiovascular disease

(1) Diagnosis and differential diagnosis of heart failure:

If BNP <100ng/L or NT-proBNP <400ng/L, the possibility of heart failure is very small, and its negative predictive value is 90%; if NP >400ng/L or T-proBNP >1500ng/L, the possibility of heart failure is very high, and its positive predictive value is 90%. For patients who present to the emergency department with obvious shortness of breath, if their BNP/NT-proBNP levels are normal or low, the possibility of acute heart failure can almost be ruled out.

(2) Risk stratification of heart failure:

BNP levels are particularly elevated in patients with severe HF. Plasma BNP levels are positively correlated with the New York Heart Association (NYHA) classification of heart failure. Those with clinical manifestations of heart failure and significantly increased BNP/NT-proBNP levels are at high risk.

(3) Assess the prognosis of heart failure:

This marker continues to rise during the clinical process, indicating a poor prognosis.