Acute aortic syndrome is also known as acute chest pain syndrome, as the name implies, chest pain is its main clinical manifestation; and the aorta is the main blood supply channel of the human body, once the lesion will seriously endanger the human life and health.
What is acute aortic syndrome? It consists of acute aortic diseases with similar clinical features and associations, including aortic coarctation, aortic wall hematoma, penetrating atherosclerotic ulcer, and aortic dissection due to trauma.
The normal aortic wall is composed of three structural layers, namely the intima, mesentery, and epia. Aortic coarctation is caused by tearing of the intima and middle layers of the aorta to form an intimal tear, which exposes the middle layer directly to the lumen, and blood flow in the aortic lumen is driven by pulse pressure to directly penetrate the diseased middle layer via the intimal tear, separating the middle layer to form a coarctation. The newly formed lumen is thus a pseudo-lumen, and because the pseudo-lumen is only wrapped by an outer membrane, the probability of aortic rupture is very high, and once the vessel ruptures the patient’s chances of survival are slim.
The annual incidence of aortic coarctation is more than 5/100,000, and hypertension is one of the most important predisposing factors. The high incidence of hypertension in China, the low awareness rate of patients, and the low percentage of patients actively treated have led to a large number of potential aortic coarctation patients. Aortic coarctation is one of the most aggressive acute aortic diseases, increasing mortality by approximately 1% without 1 hour after onset, and approximately half of patients will die from aortic coarctation rupture and its resulting serious complications within 48 hours.
Intermural aortic hematoma is caused by spontaneous rupture and bleeding of the trophoblastic vessels within the aortic wall, resulting in circumferential or crescentic thickening of the aortic wall without endothelial tears or ulcer-like lesions and true or false luminal blood flow traffic. Approximately 2/3 of intermural hematomas are located in the descending aorta. Chest pain is the most common symptom of an ascending (proximal) intermural hematoma, while back pain is the most common symptom of a descending (distal) intermural hematoma.
Penetrating atherosclerotic ulcer is an ulcer on an aortic atherosclerotic lesion that penetrates the internal elastic lamina and forms a hematoma in the middle layer. It may promote the development of intermural aortic hematomas and may progress to aneurysms, pseudoaneurysms, aortic dissection, and aortic coarctation.
Traumatic aortic dissection: Patients with complex trauma should be considered for traumatic aortic dissection if signs similar to aortic constriction are noted, including higher blood pressure in the upper extremities than in the lower extremities, later femoral pulsation than radial pulsation, and an audible rough murmur between the scapulae.
The clinical presentation of aortic coarctation, intermural hematoma, and penetrating ulcer is essentially the same. Sudden, severe chest pain is the most common symptom. The location of the pain and accompanying symptoms may reflect the site of the initial intimal tear and may indicate the possibility of entrapment extending along the aorta or involving branch arteries and organs. Pain radiating to the neck, throat, and/or jaw, especially when accompanied by an aortic regurgitant murmur and signs of pericardial tamponade, indicates involvement of the ascending aorta. In contrast, pain occurring in the back or abdomen is suggestive of involvement of the descending aorta.
The pain of acute aortic syndrome is often confused with the pain caused by acute coronary syndrome. Typical patients with aortic coarctation tend to have asymmetrical blood pressure in the extremities and elevated D-dimer, but enhanced CT examination of the aorta remains the best means of confirming the diagnosis.
The aorta is a very complex organ in the body, and the treatment of each patient with acute aortic syndrome is not fixed.
Acute aortic coarctation is staged according to the initial site of the intimal tear or whether the coarctation involves the ascending aorta (regardless of the site of origin). Since staging determines whether surgical versus non-surgical treatment is performed, accurate staging is very important. The most commonly used staging scheme is the DeBakey and Stanford staging, which is divided into 3 types based on the site of initiation of the intimal tear and the extent of entrapment extension.
Type I.
An entrapment that originates in the ascending aorta and extends distally, at least to the aortic arch but often to the descending aorta (surgical treatment is recommended).
Type II.
An entrapment originating in and confined to the ascending aorta (surgical treatment recommended). Type III: Closure originating in the descending aorta and often extending to the distal aorta (non-surgical treatment recommended). The Stanford staging scheme is more commonly used in clinical practice, and there are 2 types of Stanford staging depending on whether or not the entrapment involves the ascending aorta.
Type A.
All clips involving the ascending aorta regardless of the site of origin (surgical treatment is recommended).
Type B.
All clips that do not involve the ascending aorta (non-surgical treatment recommended).
Intermural hematoma.
Consistent with the treatment strategy for type A and type B clips, surgical treatment is recommended for patients with type A intermural hematomas, whereas pharmacological treatment is recommended for patients with type B intermural hematomas.
Penetrating ulcers.
Unlike typical aortic coarctation, penetrating ulcers are usually confined, and confined lesions provide a more ideal anatomic target for self-expanding clad stents. Studies have demonstrated the safety and efficacy of overlapping stent placement in patients with penetrating ulcers.
Patients with acute aortic syndrome involving the ascending aorta should undergo emergency surgery, whereas patients with acute aortic syndrome limited to the descending aorta should be treated medically unless there are complications such as poor organ or limb perfusion, progression of entrapment, aortic extravasation (impending rupture), intractable pain, or uncontrollable hypertension.
Initial pharmacologic therapy consists of giving drugs to control blood pressure and lower heart rate to limit the extension of the entrapment. The treatment goal is to achieve a systolic blood pressure of 100 to 120 mmHg and a heart rate of 60 to 80 beats per minute. Many patients may require multiple medications to achieve this goal. In addition, analgesics should be given to reduce pain and to provide better control of tachycardia and hypertension due to sympathetic release of catecholamines.