High blood pressure is also called hypertension, it’s a condition in which the force of blood pushes against blood vessel walls as the heart pumps out blood generating pressure in the blood vessel wall. The readings of blood pressure are written in two figures separated by a line. The upper number stands for systolic blood pressure while the bottom number for diastolic blood pressure. Systolic blood pressure is the pressure within the arteries once the heart contracts and pushes blood forward, whereas diastolic blood pressure is the pressure in the arteries when the heart relaxes. The blood pressure readings lower than 120/80 mmHg are said to be normal. know everything about renovascular hypertension, renal hypertension causes, treatment, symptoms diagnosis, complications, and so on.
Hypertension in the kidney also mentioned as renal hypertension or renovascular hypertension is a condition in which there’s the elevation of blood pressure caused by the narrowing of arteries that transport blood to kidneys.
In other words, when the blood fails to get into the kidney to remove the salt and water, there is the retention of fluids in the body. In addition, the kidney releases the hormone renin which helps retain salt and water and causes blood vessels to stiffen. Stiffening of blood vessels ends up in the build-up of pressure, resulting in renovascular hypertension.
Renal Hypertension Causes
The renal hypertension causes are :
- Renal artery stenosis –This condition leads to a decrease in the diameter of the renal arteries ( arteries that deliver blood to the kidney).
- When the kidneys obtain low blood influx, they act as the low influx is due to dehydration.
- In order to do that, they react via means of releasing hormones that stimulate the body to keep sodium and water. Blood vessels fill with excess fluid, and blood pressure goes up.
- Another reason for the narrowing of single or each renal artery is commonly due to atherosclerosis (i.e., increase of fat, cholesterol, and different materials in the artery walls) or hardening of the arteries.
- The other less common reason for narrowing is fibromuscular dysplasia (FMD) It’s a condition in which a non-atherosclerotic, non-inflammatory problem of the blood vessels causes unusual growth within the wall of an artery.
- Fibromuscular dysplasia is seen in almost every arterial bed within the body however the commonly affected arteries are the renal and carotid arteries.
- Arteritides ( inflammation or infection involving an artery or arteries) such as Takayasu’s, antiphospholipid antibody (APLA), or mid aortic syndrome
- Extrinsic compression of a renal artery| Renal Hypertension Causes
- Renal artery dissection or infarction| Renal Hypertension Causes
- Radiation fibrosis
- Obstruction from aortic endovascular graft
- Other disease conditions contributing to this are :
- Diabetes
- Hyperlipidemia or high cholesterol
- Advanced age.
How common is renal hypertension?
- Renovascular hypertension, or renal hypertension, affects people of all ages.
- Renal artery stenosis secondary to atherosclerosis is the most usual reason and is mainly seen in older adults above 65 years of age.
- It is more common in people with known atherosclerotic disease, such as patients with coronary artery disease, peripheral arterial disease, or carotid stenosis.
- Multiple autopsy studies have found that more than 25% of all patients who die from cardiovascular disease have some degree of renal artery stenosis.
- Fibromuscular dysplasia (FMD) is commonly seen in young women and accounts for approximately 10% of renovascular hypertension and 5.8% of secondary hypertension.
- FMD can affect any artery, but most commonly affects the distal two-thirds of the renal artery
Renal Hypertension Occur | Renal Hypertension Causes
The underlying mechanism of renovascular hypertension involves decreased blood flow to the kidney and activation of the renin-angiotensin-aldosterone (RAAS) signaling pathway. The hormone called “renin” is secreted by the juxtaglomerular cells of the kidney.
Renin secretion by the kidneys is initiated by three main pathways
- Renal baroreceptors, which detect decreased blood flow to the kidney,
- Low sodium chloride levels, which are detected by the macula densa, and
- Beta-adrenergic stimulation.
- Prolonged ischemia also increases the number of renin-expressing cells in the kidney, in a process called “JG recruitment”.
- When renin is eliminated in the blood, it acts on angiotensinogen (produced by the liver).
- Renin splits angiotensinogen into angiotensin I, which is then converted into angiotensin II by the angiotensin-converting enzyme (ACE), which is mainly found in the vascular endothelium of the lungs and kidneys.
Angiotensin II increases blood pressure by several mechanisms, including
- Vasoconstriction(it’s the narrowing or constriction of the blood vessels through small muscle tissue in their wall), generally within heart, kidney, and vascular smooth muscle.
- Sympathetic nervous stimulation inflicting a presynaptic release of norepinephrine.
- Stimulates secretion of aldosterone through the adrenal cortex, which in turn causes sodium and water retention, thereby elevating blood pressure.
- It additionally causes the expanded synthesis of collagen type I and III in fibroblasts, causing thickening of the vascular wall and myocardium, and fibrosis
- It has been proven to have an increase impact on renal cells, which has been implicated in the development of glomerulosclerosis and tubulointerstitial fibrosis
Though atherosclerotic renal artery stenosis (ARAS) and FMD are the main common conditions inflicting this cascade, any pathology leading to reduced blood flow to the kidneys can basically trigger this and result in excessive blood pressure.
Renovascular Hypertension Symptoms
- High blood pressure
- Blurry or double vision
- Kidney dysfunction
- Narrowing of arteries anywhere in body
- Pulmonary edema
- Loss of appetite
- Nausea
- Sleep problems
- Drowsiness
- Increased or decreased urination
- Generalized itching or numbness, dry skin, darkened skin.
- Weight loss
- Muscle cramps
- Chest pain or shortness of breath
- Hematuria
- Renal hypertension can cause chronic kidney disease. CKD is a slow decline in kidney functions.
Renal Hypertension Diagnosed
LABORATORY TESTS
Monitor Blood pressure.
Blood test
Blood for renal function tests (which includes eGFR) and electrolytes, Blood glucose.
Serology
It discovers systemic lupus erythematosus or vasculitis if suspected ( eg: antinuclear antibodies, complement).
Urinalysis
To test for proteinuria, hematuria, and casts. The presence of proteinuria suggests the presence of renal parenchymal disorder, while the presence of hematuria or red blood cell (RBC) casts suggests the presence of glomerulonephritis.
Lipid profile
As the renovascular disease is probable to be a part of more significant atherosclerotic disease.
IMAGING TESTS
Kidney ultrasound
- It is frequently carried out in people with renal impairment however it isn’t diagnostic for renovascular disease.
- The analysis is recommended if there’s a huge distinction in kidney size (>1.5 cm).
Duplex Doppler ultrasonography
This test makes use of sound waves to degree the dimensions of the stenosis in the renal arteries.
CT angiography
- This includes the management of intravenous evaluation and obtaining distinctive pictures of blood vessels or tissues by moving the beam in a helical way throughout the region being studied.
- CTA additionally has a similar negative predictive value to MRA in ruling out renal artery stenosis. It’s additionally useful in diagnosing extrinsic compression of renal arteries, FMD, arterial dissection, and assisting in comparing surrounding structures.
Renovascular Hypertension treatment
Medications are the first-line treatment, this is used to control high blood pressure in renal hypertension. The generally prescribed blood pressure medications to treat renal high blood pressure consist of:
ACE inhibitors(angiotensin-converting enzyme inhibitors).
These include ramipril, benazepril, captopril, lisinopril, and others.
ARBs (angiotensin II receptor blockers).
Examples include candesartan, losartan, telmisartan and valsartan.
- The majority of people with renal hypertension, with the help of pharmacological treatment, can efficiently manage blood pressure.
- However, more than one blood pressure drug is frequently required.
- In some patients with renal hypertension taking one or more medications might not help in controlling blood pressure, in such cases a procedure to enhance blood flow to the kidney can help. These approaches consist of:
Percutaneous Transluminal Angioplasty (PTA)
- Percutaneous transluminal angioplasty of the renal artery is an increasingly extensive peripheral vascular intervention for the treatment of Renal hypertension.
- Angioplasty aims to open the block in the renal artery and revive the blood flow.
- During this method the physician makes an incision in the groin area and inserts a catheter then guides the catheter via a large artery and advances it into the renal artery. A balloon is then inflated for some time. This widens the artery and improves blood flow.
This method is usually recommended in the following conditions:
- Patients with hemodynamically large RAS and recurrent, unexplained congestive coronary heart failure or sudden, unexplained pulmonary edema (class Ia)
- Hemodynamically large RAS and increased hypertension, resistant hypertension, malignant hypertension or hypertension with an unexplained unilateral small kidney, and hypertension with intolerance to medicine (Class IIa)
- Patients with bilateral RAS and revolutionary persistent kidney disorder or a RAS to a solitary functioning kidney (Class IIa)
- Patients with hemodynamically large RAS and unstable angina (class IIa)
- Asymptomatic bilateral or single kidney with hemodynamically large RAS (Class IIb)
- Patients with RAS and persistent renal insufficiency with unilateral RAS (class IIb)
- Besides angioplasty, renal stent placement is indicated for patients with ostial atherosclerotic lesions (Class I).
Stenting| Renal Hypertension treatment
- Renal artery stenting is a way to widen the renal arteries, the large blood vessels that deliver blood to the kidneys after they’re blocked due to renal artery stenosis (narrowing of the renal artery).
- This method opens the blockage and restores the normal blood flow.
- During angioplasty, a wire-mesh stent may be extended within the renal artery. The stent remains in place.
- This maintains the artery to open after the balloon is removed. Research, however, has now no longer proven that stenting is more efficacious than medication for renal hypertension.
Surgery| Renal Hypertension treatment
A surgeon can bypass the narrowed renal artery by sewing a healthy blood vessel next to it. Surgery is generally advised only when angioplasty and stenting are impossible.
Renovascular Hypertension Prevention
PHYSICAL ACTIVITY
- Regular activities can help in lowering blood pressure and help in lowering the chances of other health problems.
- At least 150 mins per week of moderate-intensity cardio activity is advised.
- These activities make the heart beat quicker and can cause respiration harder.
- Start by seeking to be active for at the least 10 mins at a time without breaks.
- You can count each 10-minute phase of activity towards your physical interest goal.
- Biking
- Swimming
- Brisk Walking
Biking is one type of moderate-intensity exercise that can help lower blood pressure and weight.If you have any concerns, a healthcare professional can provide information about how much and what kinds of activities are safe for you to do.
BODY WEIGHT
- For the people who are overweight or have obesity, should aim to reduce weight by 7 to 10 percent during the first year of treatment for high blood pressure.
- With this amount of weight reduction can be useful in decreasing the threat of developing health problems associated with excessive blood pressure.
- Body Mass Index (BMI) is the tool mainly used to estimate and screen for overweight or obesity found in adults.
- BMI is a measure primarily based totally on your weight in terms of height. BMI can tell if you are at a normal or healthy weight, are overweight, or have obesity.
Normal or healthy weight
A person with a BMI of 18.5 to 24.9 is in the normal or healthy range.
Overweight
An individual with a BMI of 25 to 29.9 is taken into consideration as overweight.
Obesity
An individual with a BMI of 30 to 39.9 is taken into consideration to have obesity.
Extreme obesity
An individual with a BMI of 40 or more is taken into consideration to have extreme obesity.The goal should be a BMI lower than 25 to help keep the blood pressure under control.
SMOKING
- People who smoke, should quit Smoking as it can damage blood vessels, raise the chance of developing high blood pressure, and worsen health problems related to high blood pressure.
- In case of people with high blood pressure, they should talk with their health care professional about programs and products to help quit smoking.
STRESS
Stress may be a cause of uncontrolled blood pressure. Managing stress, relaxing, and handling troubles can enhance emotional and physical health. Some activities that could assist reduce stress include :
- Being physically active
- Practicing yoga
- Listening to music
- Focusing on something calm or peaceful
- Meditating
Complications
Complications of renal hypertension especially arise because of uncontrolled blood pressure. These include:
- Aortic aneurysm
- Heart attack
- Heart failure
- Chronic kidney disease
- Stroke
- Retinopathy or vision problems.
- Poor blood supply to the legs.
- Pulmonary edema.
- Myocardial infarction.