From the Guidelines
Hypertension can cause leg edema through its detrimental effects on the cardiovascular system, particularly by leading to heart failure with preserved ejection fraction (HFpEF), as seen in studies where hypertension is the most important cause of HFpEF, with a prevalence of 60% to 89% in large RCTs, epidemiological studies, and HF registries 1.
Mechanisms of Edema in Hypertension
- High blood pressure damages blood vessel walls, leading to increased pressure in the capillaries which forces fluid into surrounding tissues, a condition exacerbated by gravity in the lower extremities.
- Hypertension often leads to heart failure, where the heart cannot pump blood efficiently, causing fluid backup in the venous system and pooling in the lower extremities, as noted in the context of HFpEF 1.
- Hypertension can also damage kidneys, impairing their ability to remove excess fluid and sodium from the body, contributing to fluid retention and edema.
- Certain blood pressure medications can worsen edema as a side effect, though the choice of medication can influence this risk, with some studies suggesting differences in outcomes based on the type of antihypertensive used 1.
Management of Hypertension-Related Edema
- Controlling blood pressure with appropriate medications is crucial, as evidenced by studies like ALLHAT, which showed that treatment of hypertension reduced the risk of heart failure 1.
- Reducing sodium intake to less than 2,300 mg daily can help minimize fluid retention.
- Elevating legs when sitting, wearing compression stockings, and regular exercise to improve circulation are non-pharmacological strategies to reduce edema.
- If edema persists, diuretics may be considered to help eliminate excess fluid, though the specific choice and dosage should be guided by clinical judgment and patient response.
From the Research
Mechanisms of Hypertension-Induced Leg Edema
- Hypertension can lead to leg edema through various mechanisms, including:
- Venous hypertension and impaired lymphatic function, which can cause an imbalance in the processes of filtration, resorption, and lymphatic transport in the capillary bed 2
- Increased capillary pressure and fluid extravasation, particularly when standing, due to the blunting of postural skin vasoconstriction by certain antihypertensive medications such as calcium channel blockers (CCBs) 3
- Changes in the arterial wall, including alterations in the endothelium, vascular smooth muscle cells, and the extracellular matrix, which can affect blood vessel function and contribute to edema 4
Role of Antihypertensive Medications
- Certain antihypertensive medications, such as CCBs, can increase the risk of leg edema by blunting postural skin vasoconstriction and increasing capillary pressure 3
- Other medications, such as angiotensin-converting enzyme inhibitors (ACEIs), may attenuate ankle swelling caused by CCBs 3
- The combination of different antihypertensive medications can have varying effects on blood pressure, arterial stiffness, and peripheral resistance, which may influence the development of leg edema 5
Underlying Pathomechanisms
- Chronic venous insufficiency and venous obstruction can lead to venous hypertension and increased filtration pressure, contributing to leg edema 2
- Primary and secondary disturbances of the lymphatic system can also cause interstitial liquid retention and edema 2
- The adaptative changes in the distal nephron in patients with chronic kidney disease may decrease the efficacy of certain diuretics, such as furosemide, and contribute to edema 6