Aortic coarctation is also known as aortic coarctation separation, aortic coarctation aneurysm, and aortic coarctation hematoma. Aortic coarctation refers to a hematoma formed when blood in the aortic lumen enters the middle layer of the aortic wall through a breach in the intima, not a dilatation of the aortic wall, as opposed to an aortic aneurysm, which used to be called an aortic coarctation aneurysm, but is now more commonly referred to as an aortic coarctation hematoma, or aortic coarctation separation, or aortic coarctation for short.
Prognosis of aortic coarctation
Most cases die within a few hours to a few days after onset, with a mortality rate of 1% to 2% per hour within the first 24 hours, depending on the location, extent and degree of the lesion.
Causes of aortic coarctation
1, hypertension: about 50% or more of patients with aortic coarctation have hypertension. Especially long-term and severe hypertension can increase the impact of hemodynamic forces on the aortic wall and put the aortic nutrient vessels in a state of spasm and pressure, causing ischemia, degeneration, necrosis and elastic fiber fracture, fibrosis and endothelial rupture of the middle layer smooth muscle, and finally forming an intercalated hematoma.
2, connective tissue genetic defects: such as Marfan syndrome, Ehlers-Danlos syndrome, congenital aortic stenosis, bilobed aortic valve and mitral valve prolapse, etc. Patients often have hereditary defects in the connective tissue of the aortic wall, manifesting as degeneration of collagen and fibrous tissue in the middle layer of the aorta, followed by cystic necrosis and lack of endothelial support, which can easily lead to endothelial rupture and formation of intercalated hematoma.
3.Atherosclerosis: It often occurs in patients with hypertension, hyperlipidemia, hyperglycemia and advanced age. Atherosclerotic plaque ruptures from the inner lumen and can form a sandwich hematoma.
4.Other: Severe aortic trauma, inflammation (syphilitic aortitis, systemic lupus erythematosus, etc.), end of pregnancy and during interventional cardiovascular treatment operations can cause aortic coarctation hematoma.
Pathological changes of aortic coarctation
The basic lesion is cystic mesangial necrosis. There is localized fracture or necrosis of the elastic fibers of the middle layer of the artery, and the stroma has mucus-like and cystic formation. Splits often occur in the ascending aorta, which experiences the greatest blood flow impact, while the distal part of the aortic arch has fewer and less severe lesions. The aortic wall splits into two layers with accumulation of blood and clots between them, where the aorta is significantly enlarged and pyknotic or cystic in shape. If the lesion involves the aortic annulus, the annulus enlarges and causes aortic valve insufficiency. The lesion may extend distally from the aortic root as far as the iliac and femoral arteries, and may also involve branches of the aorta, such as the innominate artery, common carotid artery, subclavian artery, and renal artery. The coronary arteries are generally unaffected, but the clot in the aortic root can have a compressive effect on the coronary artery opening. Most clots have transverse fissures in the origin of the intima, often located above the aortic valve, and the fissures can also be in two places, with the clot communicating with the aortic lumen. In a few cases, the endothelium is intact without fissures. In some cases, the outer membrane ruptures and causes hemorrhage. The rupture is all in the ascending aorta, and the bleeding can easily enter the pericardial cavity, or the mediastinum or the thoracic cavity if the rupture site is lower, or the mediastinum, thoracic cavity or retroperitoneal space if the rupture site is lower. Chronic dehiscence of the clamps can form a double-lumen aorta, with one duct being placed inside the other.
Aortic clamping staging
The most widely used traditional staging methods for aortic coarctation are the Stanford staging and the Debakey staging, which DeBakey et al. classified into three types based on the location and extent of the lesion.
Debakey type I: the endothelial rupture is located in the ascending aorta and extends beyond the aortic arch to the abdominal aorta, which is the most common type.
Debakey type II: endothelial rupture in the ascending aorta with extension limited to the ascending aorta or the aortic arch.
Debakey type III: the endothelial rupture is located in the isthmus of the descending aorta, with extension involving the descending aorta or/and the abdominal aorta.
Daily et al. of Stanford University classified thoracic aortic coarctation aneurysms into two types.
Where the ascending aorta is involved as stanford type A (both type I and type II), also known as the proximal type.
Type A accounts for about 2/3 of all cases and type B accounts for about 1/3.
Clinical manifestations of aortic coarctation
Depending on the location of the lesion, the main manifestations are as follows.
1.Pain
Most patients feel sudden pain in the chest, radiating to the front of the chest and back, which can extend to the abdomen, lower limbs and neck depending on the extent of the entrapment. The pain is severe and unbearable, reaching a peak immediately after the onset of the disease, and is cut or torn like. In a few cases with slow onset, the pain may not be significant.
2. Hypertension
Patients have the appearance of shock due to severe pain, anxiety, profuse sweating, pale face, and accelerated heart rate, but blood pressure is often not low or increased, or lowered if the outer membrane ruptures and bleeds. Many patients with pre-existing hypertension have increased blood pressure due to severe pain after the onset of the disease.
3.Cardiovascular symptoms
(1) Aortic valve closure insufficiency. Clamped hematoma involving the aortic annulus or affect the support of the heart valve – leaflet occurs, so there can be a sudden diastolic blowing murmur in the aortic valve area, pulse pressure widening, acute aortic regurgitation can cause heart failure.
(2) Pulse changes, usually seen in the carotid, brachial, or femoral arteries, with a diminished or absent pulse on one side, reflecting compression of a branch of the aorta or obstruction of its origin by an intimal lobe.
(3) Pulsation at the sternoclavicular joint or a pulsatile mass may be palpable in the suprasternal fossa.
(4) There may be a pericardial friction sound, and rupture of the entrapment into the pericardial cavity may cause pericardial occlusion.
(5) Pleural effusion, caused by the rupture of the intercalated layer into the pleural cavity.
4.Nervous symptoms
Aortic entrapment extending to the carotid artery or intercostal artery of aortic branch may cause cerebral or spinal cord ischemia, resulting in hemiparesis, coma, confusion, paraplegia, limb numbness, abnormal reflexes, visual and bowel disorders.
5.Compression symptoms
Aortic entrapment can cause nausea, vomiting, abdominal distension, diarrhea, black stool and other symptoms when it compresses the celiac artery and mesenteric artery; compression of the cervical sympathetic ganglion can cause Horner syndrome; compression of the recurrent laryngeal nerve can cause hoarseness; compression of the superior vena cava can cause superior vena cava syndrome; involvement of the renal artery can cause hematuria, urinary shutdown and increased blood pressure after renal ischemia.