Blood Pressure and Chronic Kidney Disease are closely interlinked, as each condition affects the other. Kidneys and circulatory systems rely on each other for common health. The kidneys filter wastes and excess fluids from the blood. They use a lot of blood vessels to do their job. However, when the blood vessels are damaged, the nephrons that filter the blood don’t receive the oxygen and nutrients needed to perform their role. Sustained high blood pressure can lead to declining kidney conditions as the arteries around the kidneys narrow, weaken, or harden. The impaired arteries can’t deliver enough blood to the kidney tissue.

What is hypertension?

High blood pressure is common among CKD patients. Depending on the CKD stage and its cause, the hypertension prevalence ranges from 60% to 90%. Blood pressure is the force of blood pushing against the blood vessel walls as the heart pumps out blood. Hypertension or high blood pressure happens when there is an increase in the amount of force that blood puts on blood vessels as it moves through the body. It can constrict and narrow the blood vessels that can eventually damage and weaken throughout the body, kidney included. 

The kidneys may no longer work properly if the kidneys’ blood vessels are damaged. When this happens, the kidneys are no longer capable of removing all wastes and excess fluid from the body. Too much fluid can shoot up the blood pressure, even more, causing more damage to the kidneys. 

Kidneys and High Blood Pressure

Kidneys are made up of about a million filtering units called nephrons. These nephrons have a glomerulus to filter the blood and a tubule that return the needed substances to the blood and pulls out additional wastes. The nephrons are supplied with a dense network of blood vessels and high volumes of blood flow. When the kidneys receive low blood flow, they treat the low flow as due to dehydration. As a response, they release Aldosterone, a hormone that stimulates the body to retain sodium and water. However, having too much of this hormone can make you lose potassium and retain sodium. As a result, the body holds too much water causing the blood volume and blood pressure to elevate. Over time, sustained high blood pressure can damage the arteries around the kidneys.

Damaged kidney arteries couldn’t filter blood well. The nephrons receive blood supply through the smallest of all blood vessels, the capillaries. Damaged arteries couldn’t receive the essential oxygen and nutrients, causing kidney function to decline.

Renal Hypertension Symptoms

Unless the high blood pressure is dangerously high, renal hypertension usually doesn’t have any symptoms. You cannot feel the narrowing of your arteries. Nevertheless, severe high blood pressure can manifest the following symptoms:

• Headaches or trouble focusing
• Confusion
• Blurry or double vision
• Increased or decreased urination
• Bloody (pink-colored) urine
• Nosebleed
• Loss of appetite
• Muscle cramps
• Generalized itching or numbness, dry skin, or darkened skin weight loss
• Chest pain
• Shortness of breath

Renal hypertension is dangerous as it doesn’t manifest any symptoms, which means organ damage can happen slowly without being detected and addressed. Your doctor may suspect renal hypertension when you have uncontrolled high blood pressure despite multiple medications.

Blood Pressure and CKD Risks

You are at risk for high blood pressure if you are older, as blood vessels thicken and stiffen naturally over time. Furthermore, if your family members have high blood pressure, you are likely to be at risk too. Men are more likely to develop hypertension before reaching age 55 while women are more likely to develop it after that age. African- American adults are more prone to high blood pressure compared to Caucasian, Asian, or Hispanic counterparts.

Additionally, unhealthy lifestyle habits such as drinking too many alcoholic drinks, eating too much sodium, and living a sedentary lifestyle increase your risk of developing high blood pressure. 

On the other hand, if you have a chronic disease including obesity and diabetes, you increase your risk of developing CKD. Your ethnicity also plays a role in developing CKD as Black, Native American, or Asian American is more prone to this condition. Moreover, among the risk factors of CKD are:

• Heart (cardiovascular) disease
• Smoking
• Kidney disease family history
• Abnormal kidney structure
• Older age
• Frequent use of kidney-damaging medications

Treatments for Renal Hypertension

Among the medications used to treat hypertension include Angiotensin-Converting Enzyme (ACE) inhibitors and ARBs (Angiotensin Receptor Blockers). However, for some people with renal hypertension, taking medications isn’t enough. In situations like these, a procedure may help to improve blood flow to the kidneys. These procedures are similar to those used to increase blood flow into the heart for people with coronary artery disease. These procedures are:

Managing Blood Pressure and CKD

You can prevent your blood pressure from skyrocketing or slow down the progression of CKD by tweaking your lifestyle and taking the proper medication. Remember to always check in with your primary healthcare provider to address your CKD or high blood pressure. You can manage CKD and high blood pressure by:

• Following a kidney-friendly diet meal plan
• Managing stress
• Maintaining a healthy weight
• Quitting Smoking and build kidney-friendly habits
• Avoiding highly processed and fast foods
• Getting quality sleep

The Bottom Line

High blood pressure contributes to the leading cause of kidney failure. Although intensive blood pressure control hasn’t been shown to slow the advancement of CKD, it can reduce the risk for adverse cardiovascular results and mortality among CKD patients. Since renal hypertension doesn’t usually show any symptoms, organ damage cannot be easily detected and managed. 

Consult with your doctor to learn more about how to manage your blood pressure and CKD properly and prevent one or the other from worsening.