The kidney is an important organ in the human body, its most important role is to excrete some metabolic wastes in the blood through urine, in addition to regulating the body’s endocrine, hematopoietic and blood pressure. The renal artery is a very important blood vessel that directly divides from the trunk aorta, supplying blood to the kidneys, and is an important way to feed and maintain the kidneys. Therefore, the narrowing or occlusion of the renal artery will have a great impact on the function of the kidney.
First of all, patients will suffer from hypertension due to renal artery stenosis, which is medically called renal hypertension, sometimes called malignant or intractable hypertension. This type of hypertension is often as high as 180, 190 or even 200 mmHg or more, and is difficult to control with medication. Subsequently, patients will suffer from gradual narrowing of the blood vessels until they become occluded, resulting in the function of the entire kidney being affected, elevated blood creatinine, and even kidney atrophy.
Why do you suffer from renal artery stenosis?
Renal artery stenosis can occur in people of all ages, with middle-aged and elderly people being the most common. In middle-aged and elderly people, renal artery stenosis is mostly caused by atherosclerosis, while in young people, it is mostly caused by aortitis or myofibrillar dysplasia.
Clinically, renal artery stenosis due to atherosclerosis is more common, and the lesion is characterized by atherosclerotic plaque causing renal artery stenosis or occlusion. Most of these lesions occur at the opening of the renal artery and are relatively limited. In addition to this, young people or children may have narrowing of the renal arteries due to a specific disease called myofibrillar dysplasia in medical terms.
Another disease that causes narrowing of the renal arteries is aortitis, which is mostly seen in young women. In addition, there are several other causes of renal artery stenosis, the most common clinically is stenosis caused by atherosclerotic plaque.
What are the risks of renal artery stenosis to the body?
Mild renal artery stenosis is not so severe as to cause harm to kidney function. When the stenosis becomes severe, generally greater than 70%, it will cause a reduction in blood flow to the kidneys and kidney function will be affected. The more severe the stenosis, the greater this effect will be and the greater the threat to the kidneys.
In addition, when the renal artery stenosis reaches a certain level, the kidneys will be ischemic, causing the kidneys to produce a substance that causes a reflex increase in the patient’s blood pressure, medically called changes in the renal angiotensin-aldosterone system, resulting in a state of hypertension that is difficult to control with medication in severe cases. In clinical practice, we call this renal hypertension. Therefore, renal artery stenosis has two main dangers: one is the effect on the kidney function itself; the other is renal hypertension.
There have been clinical cases in which some elderly people usually have hypertension, diabetes and atherosclerosis, but they do not pay attention to the examination of systemic blood vessels. Got the renal artery stenosis was not found in time, and suddenly there was a period of time, the blood pressure appeared malignant signs, eating antihypertensive drugs can not be controlled. The checkups were only about blood tests and liver function, but the examination of blood vessels was neglected, resulting in serious damage to the kidney function. The narrowing of blood vessels became more and more serious, and the kidney also atrophied, and finally uremia appeared.
What tests can help to confirm the diagnosis of renal artery stenosis?
In addition to clinical symptoms such as high blood pressure and changes in kidney function that can prompt us to think about the possibility of renal artery stenosis, many cases do not have any symptoms in the early stages of getting the disease, and sometimes a renal artery plaque or stenosis is found during a physical examination. So what tests are available to help detect or confirm the diagnosis of renal artery stenosis?
First, renal artery ultrasound, ultrasound examination is convenient, non-invasive and accurate. Experienced ultrasonographers can determine the degree of stenosis of the renal arteries, the site of stenosis, the blood flow rate at the stenosis site and the size of the kidney more precisely; second, CT angiography, which is commonly known as CTA, this test requires the use of angiographic contrast agent.
Therefore, in the hours before and after the examination, drink a lot of water and urinate more, which will help to excrete the contrast agent as soon as possible, thus reducing the damage of the contrast agent to the kidneys; third, nuclear magnetic angiography, nuclear magnetic angiography is also a better examination method, but the contrast agent of nuclear magnetic angiography also has certain damage to the kidneys and should also be alert;
Fourth, arteriogram, arteriogram is a damaging test that requires arterial puncture and cannulation, which needs to be done under the supervision of an X-ray machine, and also requires contrast agent, so this method is not used as a preliminary test, and is usually only used when the patient is ready for balloon dilation or stenting surgery.
How to treat renal artery stenosis?
In renal artery stenosis, the treatment can be divided into two categories: one is the surgical intervention approach, which is to take surgical or endovascular intervention (balloon dilation or stent implantation); the other, is the conservative treatment by taking medications. How to choose these two different treatment methods? The principles are: first, the degree of renal artery stenosis; second, the degree of kidney function affected; and third, the degree of hypertension.
At present, it is considered that the degree of renal artery stenosis of 70% or more requires surgical intervention. Otherwise, further aggravation of the stenosis will inevitably seriously affect the renal blood supply, leading to impairment of renal function and causing severe hypertension, etc. If the degree of renal artery stenosis is relatively mild, with less than 70% stenosis, and the renal blood flow is not greatly affected, it can be closely observed and controlled by taking medications.
The main cause of renal artery stenosis is atherosclerosis, so in the treatment, we also need to take some drugs to control the progress of atherosclerosis, such as, controlling blood lipids, antiplatelet, etc. At the same time, we need to quit smoking, control high blood pressure, high blood sugar and other risk factors that induce atherosclerosis, eat a healthy and reasonable diet, avoid eating foods or drugs that are harmful to the kidneys, etc.
There are two main types of surgical treatment for renal artery stenosis, one is minimally invasive endovascular treatment, which is commonly known as renal artery stenting. The purpose of placing a stent is to prop up the stenosis by a special alloy stent to restore effective blood flow to the kidney and achieve the goal of treating renal artery stenosis. This treatment is minimally invasive and usually involves an arterial puncture in the femoral artery, delivery of the stent to the lesion through a guidewire and catheter, and firm fitting of the stent to support the narrowed renal artery through balloon dilation. The procedure is minimally invasive but technically demanding.
Another type of surgical treatment is surgery. Surgical treatment requires an experienced vascular surgeon. Surgery is a more invasive treatment. It is performed by directly stripping the plaque from the stenotic area of the renal artery or by vascular bypass, with the help of the body’s own veins or artificial vessels, which are grafted to both ends of the stenotic lesion, one end to the aorta and the other to the renal artery. Due to the deep location of the kidney, surgical treatment is more invasive and is usually used when minimally invasive endoluminal treatment is not suitable.
What do I need to pay attention to after renal artery stenting?
After stenting the renal artery, it is not a safe deposit box, but there are still many issues that need to be taken care of.
①Continue to insist on treatment for the cause, such as treatment of atherosclerosis, aortitis, etc.;
②Adhere to the medication, in addition to the treatment of the original disease, but also take anti-platelet drugs to prevent restenosis and thrombosis of the stent;
③Continue to control hypertension and protect the kidneys;
④Be sure to review regularly to keep abreast of the patency of the kidney stent and changes in kidney function, and solve problems in time to prevent future problems.
Summary
Renal artery stenosis is the “hidden killer” that causes hypertension and kidney function damage, but as long as we understand the characteristics of this “killer”, we can detect renal artery stenosis early and treat it in time to protect our kidney function.