How Does Aldosterone Affect Blood Pressure: Cause, Screening and Treatment

How does aldosterone affect blood pressure? Many people suffer from high blood pressure, but it's challenging to control.

They go to the hospital for tests on their renin levels, but the results show that they are low. Many people are puzzled because isn't renin level supposed to be positively correlated with blood pressure? Why is it that renin is low, but their blood pressure remains high?

The Relationship between Renin, Aldosterone, and Hypertension

How does aldosterone affect blood pressure? In the human body, there is a blood pressure regulation mechanism known as the renin-angiotensin-aldosterone system (RAAS). Renin is released by the juxtaglomerular cells of the kidneys, and through the action of a series of converting enzymes, it generates angiotensin, causing an increase in blood pressure, and it also promotes the release of aldosterone.

Aldosterone promotes the excretion of potassium while retaining sodium ions and water, leading to sodium and water retention and an increase in blood pressure. However, certain conditions, such as tumors, primary hyperaldosteronism, nephrotic syndrome, and others, can also result in an excess secretion of aldosterone.

Excessive aldosterone can, in turn, inhibit renin secretion, manifesting as low renin levels while blood pressure remains high. Some individuals may also experience low blood potassium levels in this scenario, accompanied by symptoms like weakness, digestive problems, and irregular heart rhythms. Aldosterone can also mediate inflammatory responses and abnormal proliferation of fibroblasts, leading to hypertrophy and fibrosis of heart muscle cells, increasing the risk of heart failure.

Slow loss of potassium ions can lead to degeneration of renal tubule epithelial cells, reducing reabsorption function, and resulting in symptoms like increased urination and nocturia. If hypertensive patients exhibit these symptoms, they can be diagnosed through renin and aldosterone testing.

After an increase in aldosterone, the most common symptom is high blood pressure. However, the pharmacological mechanisms of commonly used antihypertensive drugs cannot counteract aldosterone, leading to resistant hypertension. In other words, using three or more antihypertensive drugs does not significantly lower blood pressure.

Screening and Treating Primary Aldosteronism

The above explains “How does aldosterone affect blood pressure?”. Hypertension is typically considered a primary condition with an unknown cause that requires long-term, and even lifelong, medication. However, a portion of hypertension cases is secondary to other underlying conditions, including primary aldosteronism, which is one of the most common secondary causes of high blood pressure.

Clinical presentation primarily involves hypertension with low blood potassium levels, which can be either mild or severe but rarely malignant. Primary aldosteronism accounts for 5-10% of hypertensive patients and approaches 20% in those with resistant hypertension.

The following individuals should be screened for primary aldosteronism:

1.Sustained elevated blood pressure (≥150/100 mmHg) with insufficient control using three or more antihypertensive drugs (BP >140/90 mmHg).

2.Hypertension is accompanied by spontaneous or diuretic-induced low blood potassium.

3.Hypertension with an adrenal tumor.

4.Early-onset hypertension (<20 years) or a family history of early-onset stroke (<40 years).

5.Hypertensive patients with primary aldosteronism among first-degree relatives.

Why should you screen for secondary hypertension, especially primary aldosteronism? Because, compared to primary hypertension, primary aldosteronism is more likely to cause damage to target organs like the heart and kidneys. Additionally, the treatment approach for primary aldosteronism differs from that of primary hypertension.

Therefore, early diagnosis and treatment are crucial, as treatment involves not only lowering blood pressure but also countering the toxic effects of aldosterone. For primary aldosteronism treatment, surgical intervention may be considered for aldosterone-producing tumors, while spironolactone or eplerenone, aldosterone receptor antagonists, may be used for aldosterone-producing adenoma.

In the case of primary hyperaldosteronism, dietary and lifestyle modifications, while helpful in reducing blood pressure, are usually no substitute for medication. But they can still have a mitigating effect.

First, reduce your salt intake by avoiding excessive salt and salty foods, such as processed foods and salty snacks. At the same time, increase your potassium intake by eating potassium-rich foods, such as bananas, potatoes, and leafy green vegetables, which can help offset the adverse effects of salt on blood pressure. In addition, controlling your weight, following the DASH diet, limiting alcohol and caffeine intake, and reducing consumption of processed foods can all have a positive impact on the management of hypertension.