What is aortic coarctation?
Based on the presence or absence of self lesions in the aortic wall and under the action of a series of external factors (hypertension, trauma, etc.) leading to tearing of the aortic intima, blood enters the middle layer of the aortic wall by the intimal fissure, causing the separation of the middle layer of the aorta along the long axis, which results in a pathological state of true and false lumen of the aortic lumen.
What is the prognosis of aortic coarctation?
Death can occur suddenly or within a few hours or days in patients with acute entrapped aneurysms. A meta-analysis of patients with a coarctation aneurysm in the literature found that 50% of them died within 48 hours, with a 1% risk of death per hour. 70% died within 1 week and 90% died within 3 months. The main causes of early death are aneurysm rupture leading to death by hemorrhagic shock or obstruction of an artery supplying vital organs, such as the coronary, carotid or visceral arteries.
So what kind of people are prone to aortic coarctation? That is, what is the cause or causes of aortic coarctation?
Aortic coarctation is the result of the interaction between the structure of the membrane in the aorta and abnormal hemodynamics. When the aortic structure is abnormal, it is naturally susceptible to fracture of the intra-aortic mesentery. Common factors include Marfan syndrome, congenital cardiovascular malformations, idiopathic degenerative changes in the aortic mesentery, aortic atherosclerosis, aortic inflammatory disease, etc. We know the American female volleyball player Hyman and the male volleyball player Zhu Gang both collapsed on the sports field for these reasons.
Arterial wall damage is also easily caused when hemodynamic changes occur. The most common cause is hypertension, and almost all patients with aortic coarctation have poorly controlled hypertension. In other words, the control of hypertension has a comprehensive impact on the prevention, treatment, and prognosis of aortic coarctation, and is the most basic and least negligible means of treatment and prevention. Pregnancy is another high incidence factor, associated with altered hemodynamics during pregnancy.
Among women who develop the disease before the age of 40, 50% occur during pregnancy. The ratio of male to female incidence of aortic coarctation is 2 to 5:1; the common age of onset is between 45 and 70 years, with the youngest patient reported so far being only 13 years old.
There are two major medical classifications of aortic coarctation based on the location of the intimal fissure and the extent of coarctation involvement. The most widely used is the type III classification proposed by Professor DeBakey et al. in 1965. Type I: Aortic coarctation involves the ascending aorta to the descending aorta and even to the abdominal aorta. Type II: Aortic coarctation is limited to the ascending aorta.
Type III: Aortic coarctation involving the descending aorta, such as downward involvement of the abdominal aorta is type IIIA; downward involvement of the abdominal aorta is type IIIB. In 1970, Professor Daily of Stanford University and others proposed another classification method based mainly on the location of the proximal endothelial fissure: Stanford type A: equivalent to DeBakey type I and II; Stanford type B: equivalent to DeBakey type III. Type B: equivalent to DeBakey type III.
What are the main clinical symptoms of aortic coarctation?
In practice, it can be manifested in different situations, mainly including some of the following.
1. A typical patient with acute aortic coarctation often presents with sudden, severe, chest and back, tearing-like pain. In severe cases, heart failure, syncope, and even sudden death can occur; most patients also have uncontrollable hypertension;
2. Aortic branch artery occlusion can lead to corresponding ischemic symptoms in brain, limbs, kidneys, and abdominal organs: such as cerebral infarction, oliguria, abdominal pain, pale legs, weakness, florid spots, and even paraplegia.
3. In addition to the above main symptoms and signs, because of the wide area of aortic blood supply, the performance varies according to the accumulation range of the entrapment. Other conditions include: disappearance of peripheral arterial pulsation, vocal cord paralysis when the left recurrent laryngeal nerve is compressed, hemoptysis and vomiting of blood when the entrapment penetrates the trachea and esophagus, superior vena cava syndrome when the entrapment compresses the superior vena cava, dyspnea when the trachea is compressed. Compression of the cervicothoracic ganglion may lead to Horner’s syndrome, compression of the pulmonary artery may lead to pulmonary embolism, and involvement of the mesenteric and renal arteries may lead to intestinal paralysis or even necrosis and renal infarction. Pleural effusion is also a common sign of aortic coarctation, mostly on the left side.
How is aortic coarctation diagnosed?
The main adjuncts to diagnose aortic coarctation are CT angiography (CTA), magnetic resonance imaging (MRA) or direct digital silhouette angiography (DSA).
How is aortic coarctation treated?
Conservative treatment
In patients with acute coarctation, whatever further treatment is required, the first step should be conservative treatment: blood pressure control and pain control. This usually involves the application of powerful drugs such as sodium nitroprusside for blood pressure and morphine for analgesia. For patients in critical conditions, emergency tracheal intubation, ventilator-assisted breathing, and emergency resuscitation surgery are often required, but this also implies a very high risk and mortality rate.
Surgery and interventional treatment
After the patient is appropriately stabilized, the choice of treatment modality depends mainly on the type of entrapment. For the current state of treatment, for Stanford type B aortic coarctation, minimally invasive endoluminal treatment is the mainstay. The basis for treatment includes the following conditions, or indications for surgery: persistent enlargement of the entrapment, as evidenced by a rapidly increasing diameter and extent of the aortic entrapment, thoracic hemorrhage, and uncontrollable pain; or ischemia of major branches of the aorta, such as the superior mesenteric artery and renal artery.
Traditional minimally invasive endoluminal repair of aortic coarctation technically requires at least a 37.5 px anchorage zone on the aorta to prevent incomplete proximal occlusion and endoleaks. However, with improvements in endoluminal repair devices and advances in endoluminal repair techniques, this indication has been expanded to allow treatment of Stanford type B aortic coarctation with a main cleft within 37.5 px of the left subclavian artery opening by hybridization or various endoluminal repair coarctures (chimney, open window, modular branch stent).
Intraluminal repair of Stanford type A aortic coarctation with a cleft in the ascending aorta has been described with placement of a clad stent in the ascending aorta to isolate the proximal coarctation cleft, but this procedure requires specific anatomic constraints. In the acute phase, ascending aortic replacement is performed, and Sun’s procedure remains the primary treatment for type A aortic coarctation today.