Many people are unfamiliar with the term aortic coarctation and do not pay enough attention to the dangers of this disease. In fact, aortic coarctation is not uncommon, and the danger it poses to people is so great that it needs to be given great attention.
As we all know, the aorta is the main artery of the human body, and all important large branch arteries are issued from the aorta. The aorta has three layers of structure, from the inside to the outside, which are the intima, the mesentery and the epi-artery in that order. The aorta is directly impacted by the blood flow pumped from the heart, subjecting its intima to tremendous blood flow pressure. Once the intima is broken, blood flow enters under the intima causing the separation of the intima and the epima to form an arterial coarctation. The human aorta is “?” shaped with a curved tip, which is also known as the “aortic arch” in medicine. Blood flow makes a sharp turn here, causing a strong shear force on the arterial intima, and when blood pressure rises abnormally, the strong blood flow shear force may tear the arterial intima and form a fissure, resulting in aortic coarctation. Therefore, the aortic arch is a “high-risk location” for aortic coarctation.
1.Who is prone to aortic coarctation?
The common causes of aortic coarctation are hypertension, atherosclerosis, Marfan’s syndrome and arterial inflammation, among which hypertension and atherosclerosis are the most common causes. Patients with hypertension enter the age of prevalence of aortic coarctation 10 to 15 years after the onset of the disease. In recent years, the incidence of hypertension in our population has increased significantly and has reached 10%, with the number of patients reaching 1.2 billion, and continues to grow at a rate of more than three million people per year. Moreover, there are two characteristics of our hypertensive population: first, the proportion of young patients has increased, and second, the number of patients with unstable hypertension has increased. This is the main reason why the incidence of aortic coarctation in China has increased significantly. Among hypertensive patients, those with fluctuating and uncontrolled blood pressure have an increased risk of aortic coarctation compared to those with stable and well-controlled blood pressure, and strict blood pressure control can effectively reduce the occurrence of aortic coarctation.
2.What are the symptoms of aortic coarctation?
Patients with aortic coarctation often present with sudden onset of severe pain in the chest and back, often accompanied by profuse sweating and difficulty breathing. The pain often goes down the aorta in the back and feels like it is tearing the skin. This is medically known as “tearing pain” and is an important guide to the diagnosis of aortic coarctation. As the aortic lining tears, blood flows down the gap to the middle layer of the vessel, creating a lumen – a false lumen – that did not exist. The original lumen (true lumen) may be deflated by the pseudolumen, resulting in narrowing or occlusion of the lumen of the branch artery at the corresponding site and manifestations of inadequate blood supply to the corresponding organ. For example, obstruction of blood supply to the spinal cord may result in sudden paraplegia, obstruction of blood supply to the kidneys may result in anuria, obstruction of blood supply to the internal organs may result in abdominal pain, etc. Arterial entrapment can also progress upward along the rupture, known as a “reverse tear”. In some cases, the tear may go all the way to the ascending aorta and aortic valve, leading to cardiac insufficiency or even cardiac arrest. At the same time, blood pressure directly acts on the middle and outer membranes of the artery after the endothelial tear, and the aortic wall becomes very weak. If the blood pressure is not controlled carefully, the entrapment may rupture, leading to hemorrhage or even death.
3.What are the types of aortic coarctation?
Depending on the location of the aortic coarctation, the treatment varies. In order to facilitate clinicians’ diagnosis and guide treatment, various staging methods have been developed. Currently, there are two internationally popular staging methods.
(1) DeBakey typing: There are 3 types.
Type I is an endothelial laceration located in the ascending aorta or the arch, and the extent of stripping extends to the arch and descending aorta and even to the arteries of the lower extremities, including those in which the laceration is located in the left arch and the endothelium is stripped retrogradely to the ascending aorta.
Type II endothelial lacerations are the same as type I, but the hematoma is limited to the ascending aorta and arch.
Type III endothelial laceration is located in the aortic isthmus, distal to the left subclavian artery.
(2) Stanford typing. Type A includes Debekay type I and II and those whose rupture is located in the left arch with retrograde dissection to the ascending aorta; type B refers to those whose intimal tear is located in the isthmus of the aortic arch and spreads below the thoracic aorta.
4.What tests are needed for aortic coarctation?
When encountering patients with sudden onset of chest and back pain, the possibility of acute aortic coarctation needs to be considered, but attention needs to be paid to differentiate it from acute heart attack. Therefore, ECG and chest X-ray, which are easy and routine tests, are necessary. Unless the entrapment leads to pericardial effusion, or involves the coronary artery leading to myocardial infarction, there are usually no specific changes in the ECG. In contrast, acute heart attack usually has typical ECG changes. A chest radiograph can observe the presence of aortic widening or upper mediastinal widening, which has no diagnostic value but can suggest the need for further confirmatory tests.
Echocardiography can observe the true and false lumen of the aortic coarctation or the endothelial fissure of the aorta, but it may be affected by the air in the airway and there is a possibility of missing the diagnosis. The most important and diagnostic value is still the CT angiography (CTA) or magnetic resonance angiography (MRA) examination. In particular, CTA technology can clearly show the blood flow in the true and false lumen of the aorta, especially when combined with computerized 3D reconstruction technology, it can reproduce the spatial structure of the aortic intimal tear, thus becoming the “gold standard” for the diagnosis of aortic coarctation at this stage.
5.What treatments are available?
Aortic coarctation is a very dangerous disease with a high mortality rate, and must be treated immediately once detected.
First of all, blood pressure should be strictly controlled. As we mentioned earlier, hypertension is the most common cause of aortic coarctation. Moreover, once arterial entrapment occurs, the patient’s blood pressure will continue to rise due to severe painful stimulation, which will aggravate the entrapment lesion or even lead to bleeding and death from entrapment rupture. Therefore, patients with aortic coarctation must first be stabilized by strict blood pressure control and immediate analgesia.
The next step is to consider whether surgery is needed, when to operate, and what type of procedure to use. In the mid-19th century, patients with aortic coarctation had no chance of surgery at all and were virtually incurable because there was no suitable vascular substitute. It was not until the late 1950s, with the advent of artificial blood vessels, that artificial vessel replacement was developed as an effective treatment. The purpose of this procedure is to replace a vessel that has torn into a sandwich with an artificial vessel, removing the “dangerous structure” in the body and reconstructing the important branch vessels involved. Artificial vessel replacement has been performed for nearly 60 years and has evolved into a variety of different procedures, and remains an important surgical procedure for the treatment of aortic coarctation. However, the operation requires open chest or open abdomen, which is complicated, traumatic, bleeding, slow recovery, and requires high physical status of the patient and more postoperative complications. Many patients even lost the opportunity to be treated because they could not tolerate the surgery. Therefore, in the 1990s, a minimally invasive procedure, endoluminal therapy, came into being. Instead of opening the chest or abdomen, a small incision is made in the groin, and under X-ray fluoroscopic surveillance, an aortic stent containing the appropriate size of the aortic overlay is introduced through the femoral artery, which is then opened and fixed to the inner wall of the aorta after reaching the site of the aortic dissection, thus closing the intimal fissure. In this way, the blood flow in the aorta passes through the stent and does not continue through the fissure into the false lumen, thus avoiding the risk of further development or even rupture of the coarctation. Instead, the residual blood within the arterial false lumen will gradually form a thrombus fixation eventually transforming into a fibrous scar. Many patients can eat the same night after surgery and can get out of bed the next day. The incidence of surgical complications and mortality rates are greatly reduced, enabling many patients who do not have the ability to tolerate traditional surgery to receive effective treatment and prolong their lives. Nowadays, with the advancement of technology and materials, many patients do not even need to make an incision, and the whole process of aortic stent release can be completed by direct skin puncture, and only a few millimeters of puncture eye will be left in the groin after completion, even without sutures, thus achieving the true sense of minimally invasive.
6.What do I need to pay attention to after surgery?
Generally speaking, after aortic coarctation, try not to do strenuous exercise in the short term. Within three months to six months after the surgery, the patient should be in a relatively stable state so that the artificial blood vessel or stent can fully fit with his own blood vessel. Generally speaking, as long as there is no heavy physical work, you can go to work after two weeks of rest after discharge from the hospital, but of course, it is quite necessary to rest in between work. At the same time, it is important to follow up with the vascular surgery clinic regularly to observe the general physical status and to know the regression of the entrapment, whether the lesion has progressed, whether the original false lumen is closed and whether the stent position has moved.
Aortic coarctation is a serious threat to human health and even life, which brings a great burden to individuals, families and even society. Although surgery can treat the symptoms of aortic coarctation, treatment of the cause is fundamental to long-term treatment. As we mentioned before, hypertension and atherosclerosis are the main causes of aortic coarctation, so in order to prevent the recurrence of similar lesions, regular anti-hypertensive and anti-atherosclerotic treatment is required. This cannot be solved overnight, but requires long-term persistence in our life. On the one hand, we need to develop good habits, quit smoking and drinking, and avoid overexertion; on the other hand, we need to treat hypertension, diabetes, hyperlipidemia and other risk factors of atherosclerosis, and take regular medical checkups to prevent them before they happen.