What is renovascular and vasorenal arterial hypertension?

Renovascular hypertension is a disease in which there is a regular increase in blood pressure. Pathology is characterized by a decrease in the lumen of the renal artery or its branches. As a result, blood flow to the organ is disrupted, which causes ischemia of its tissues. The form of manifestation of the pathology depends on the severity of the damage to the blood channels.

The most commonly diagnosed stenosis of the renal artery of atherosclerotic origin. This pathology develops mainly in older people. The male half of humanity is more susceptible to this disease.

Pathogenesis and causes of the disease

Since with renovascular hypertension there is a decrease in blood flow in the kidneys, they begin to produce the hormone renin, which is precisely responsible for regulating blood pressure on the walls of blood vessels.

By itself, it does not have any negative effect, but with poor kidney function, this hormone activates an element such as angiotensin II. It is he who causes stenosis of the arteries, disrupts blood flow, retains water and sodium in the kidneys.

As a result of a constant lack of blood supply, the body reacts as if it were blood loss. Because of this, a protective reaction is activated, which manifests itself in the form of a constant production of hormones, that is, arterial narrowing. Due to the excessive concentration of renin and angiotensin II, there is a regular increase in blood pressure.

The most common causes of renovascular hypertension are atherosclerosis of the main renal blood vessels and fibromuscular dysplasia. Sometimes vasorenal arterial hypertension develops due to thrombosis of the renal vessels, complications after treatment of vascular pathologies, abdominal trauma, atrial fibrillation, Takayasu's disease, aneurysm, oncology, nodular polyangiitis, cysts, renal tuberculosis, genetic abnormalities.

The risk group includes people with:

• elevated levels of lipids or lipoproteins in the blood;
• atherosclerosis;
• diabetes
• smokers.

But with atherosclerotic changes in the renal blood channels, atherosclerosis of other arteries or a deterioration in lipid metabolism does not always occur. As a rule, atherosclerotic deposits are local in nature and form at the mouth or in the proximal third of the left renal blood arteries. In some embodiments, the lesion may be bilateral.

If the development of atherosclerosis occurs against the background of bilateral hemodynamic stenosis and the formation of cholesterol embolism, kidney dysfunction appears in the form of ischemic pathology. In about a third of patients, the cause of renovascular hypertension is fibromuscular dysplasia of the renal vessels.

This pathology is characterized by damage to the walls of the blood channels, which is not inflammatory. During the disease, the smooth cells of the media are transformed into fibroblasts and, in parallel, at the turn of the adventitia, form bundles of elastic fibers. This leads to the appearance of constrictions, which alternate with areas of aneurysmal expansions. Fibromuscular dysplasia is most often found in women.

In addition, it was proved that the presence of fibromuscular dysplasia in direct relatives served as a predisposition to this disease in heirs. Scientists explain this factor by a mutation of the a1-antitrypsin gene. Changes most often occur in the distal region of the renal vessel.

Symptoms and clinical signs

Renovascular hypertension is defined on the basis of a number of signs characteristic of hypertension and renal pathologies. The main manifestations depend on the form of the disease: benign or malignant. The difference between both types is that in the first case the disease progresses slowly, in the second - quickly.

In benign renovascular hypertension, there is:

• dyspnea;
• dizziness;
• discomfort in the chest;
• general weakness.

Malignant pathology is characterized by:

• persistent headaches in the back of the head;
• visual impairment;
• nausea;
• gag reflex.

In addition, the course of the disease depends on the cause of its occurrence. It was noted that vasorenal hypertension appeared in those who had consistently high blood pressure readings at a young age, rapidly developing hypertension in the elderly, and any damage to the blood channels of the kidneys.

With renovascular hypertension, diastolic pressure indicators increase significantly, which during examination is the main sign in the direction of establishing this diagnosis. Also an important symptom of such a pathology is the lack of the proper effect of treatment with antihypertensive drugs. But this factor confirms the diagnosis only if it is supported by other signs characteristic of this disease.

During the examination, the doctor listens to the organ with a stethoscope, placing it on the left or right on the abdominal cavity, or on the lower back, in an area where a narrowing of the blood channel is possible. Noises are mainly ascertained in fibromuscular dysplasia, much less often in atherosclerotic or other lesions.

A feature of the disease is that it is much more likely than other types of hypertension to have a malignant form. So, according to statistics, with bilateral kidney damage, it is observed in more than 60% of patients.

Diagnosis of hypertension: necessary tests

To fully confirm the diagnosis of "renovascular hypertension", you will need to undergo an examination in the clinic. If you suspect this pathology, it is very important to consult a doctor in time. Timely medical treatment will eliminate the causes of circulatory disorders, thereby preventing the progression of the pathology.

To confirm the diagnosis, the doctor may prescribe the following examinations:

1. Ultrasound or tomography. With unilateral renovascular hypertension, these studies reveal a decrease in the parameters of the organ in which the artery is damaged.
2. excretory urography. This procedure not only shows the different sizes of organs, but also makes it possible to reveal the low excretory function of the affected kidney (indicates ischemia).
3. Radioisotope renography. This is the most commonly prescribed medical examination. It allows you to evaluate and analyze the functions of both kidneys. Thus, a pronounced narrowing of the vessel significantly reduces the functioning of a diseased organ compared to a healthy one. But this diagnostic method is ineffective when bilateral kidney damage occurs. Also, according to the results, it is impossible to establish the cause, location and extent of the lesion.
4. Selective angiography. This survey is the most reliable. But they do it only in specialized centers. This method makes it possible to determine the nature of renovascular hypertension, to assess the degree and location of the narrowing of the artery.
5. Blood analysis. Hypertension of a renovascular nature is indicated by an increased, more than one and a half times, renin activity in the blood plasma.
6. Saralazin. An angiotensin blocker is often used to determine this disease. The essence of the procedure lies in the fact that after the introduction of the drug to the patient, his blood pressure indicators sharply decrease.

Treatment of hypertension

Treatment of the renovascular type of hypertension is aimed primarily at lowering the arterial tonometer readings. In addition, timely access to a doctor can prevent complications of the cardiovascular system and prevent the occurrence of kidney failure.

Medical treatment

Conservative treatment includes:

1. A diet that primarily limits salt intake (no more than three grams per day).
2. The restoration of the correct metabolic processes is being carried out.
3. The bad habit in the form of nicotine addiction is eliminated.
4. Medications are prescribed to reduce the risk of developing cardiovascular pathologies.

With regards to drugs, ACE inhibitors with angiotensin receptor blockers can be prescribed for renovascular hypertension. The latter are especially important, as they affect the cause of high blood pressure. At the initial stage of renovascular hypertension, such drugs can cope with the disease in more than 80% of all cases. But with a later diagnosis, they are not effective.

• Unilateral failure. Since these drugs have anti-atherogenic and cardioprotective properties, their use is advisable only for unilateral lesions.
• Bilateral failure. In the case of bilateral pathology, treatment with these medicines is not prescribed, since they can provoke acute renal failure. In addition, during the use of inhibitors and blockers, it is necessary to check the level of potassium and creatinine in the blood every six months.

In addition to the above drugs, the doctor may prescribe treatment with slow calcium channel blockers of the dihydropyride series. These medicines well lower pressure, slow down the process of formation of cholesterol deposits. But monotherapy rarely gives the desired result.

The most commonly prescribed additional drugs:

• alpha blockers,
• beta blockers,
• diuretics,
• imidazoline receptor agonists.

With atherosclerotic vascular disease, the use of statins is prescribed. On the recommendation of a doctor, they can be taken both independently and together with ezetimibe.

Surgery

If medical treatment fails, surgical intervention is possible.

Most often, such a procedure involves surgical correction in the form of angioplasty of the affected artery.

Also, to expand the lumen of the vein, stenting is used (installation of an intra-arterial frame).

Until the middle of the last century, only the nephrectomy method was used in the surgical treatment of renovascular hypertension. It was used for unilateral lesions and advanced disease. This method is also used now, but only when the predominance of narrowing of the intrarenal arteries or severe hypoplasia is stated. Often, doctors prefer to perform organ-preserving operations.

Since vasorenal hypertension increases the load on the kidneys, but at the same time their filtering abilities decrease, without timely diagnosis this can be fraught with very negative consequences, even death.

So, very often the development of the disease leads to:

• hypertrophy of the myocardium of the left heart ventricle (the consequence may be a heart attack, heart attack),
• renal failure of both organs at once,
• pulmonary edema.

Renovascular hypertension at the initial stage does not have pronounced symptoms. Because of this, patients rarely go to the clinic, attributing their condition to a “common” malaise and a “slight” increase in pressure. This attitude leads to the fact that the pathology becomes chronic. Which in the end can result in disability or death.