Conservative expectant tactics can be used for isolated aneurysms of small size that do not cause clinical symptoms. In this case, patients are prescribed antihypertensive drugs, blockers, statins.
At the same time, every six months, patients are shown a dynamic observation, including a cardiologist examination, an echoCG, CT scan or MRI. Surgical treatment of aneurysm of the aortic arch over 5 cm in diameter, occurring with pain or compression syndrome, as well as aneurysm, complicated by dissection, rupture and thrombosis.
Radical treatment consists of resection of the aortic arch aneurysm. The essence of the operation consists in excision of the aneurysm with replacement of the aortic defect with allograft, imposition of an anastomosis of the brachycephalic trunk, left common carotid and left subclavian arteries with a vascular prosthesis. The operation is performed under conditions of artificial blood circulation with protection of the myocardium and brain from ischemia using hypothermia. Surgical mortality in this type of operation is about 5-15%. Long-term results after resection of the aortic arch aneurysm are good.
In addition to open surgery for aortic arch aneurysms, closed endovascular stenting (prosthetics) of the aneurysm is used. At the same time, a special endoprosthesis with the aid of a conductor is inserted into the lumen of the aneurysm and fixed above and below the aneurysmal sac. In some cases, in the presence of absolute contraindications to performing a radical operation, palliative intervention is carried out, which consists in enveloping the aneurysm with synthetic tissue with a threatening rupture.
Aortic arch aneurysm – diffuse or local expansion of the aortic lumen on the segment between its ascending and descending part, exceeding the normal diameter of the vessel. Aneurysm of the aortic arch can manifest as shortness of breath, cough, dysphagia, hoarseness, swelling and cyanosis of the face, swelling of the neck veins, which is associated with compression of nearby organs. Diagnostic tactics for suspected aortic arch aneurysm include chest x-ray, echoCG and UZDG of the chest aorta, aortography, CT scan and MRI. The treatment consists in resection of the aortic arch aneurysm in infrared conditions with the installation of an allograft or endoluminal prosthetics of the aneurysm with a special endoprosthesis.
Depending on the level of localization, there are aneurysms of the aortic root and Valsalva sinuses, the ascending aorta, the aortic arch, the descending aorta, the abdominal aorta. Quite often in cardiology and cardiac surgery, there are combined lesions of adjacent segments of the aorta. Thus, aortic arch aneurysms are rarely found in isolation; in most cases, they are a continuation of the aneurysmal expansion of the root or ascending aorta.
The aortic arch is usually called the part of the aorta, located between its ascending and descending sections. The aortic arch passes between the pulmonary arteries and bends around the left main bronchus. Three large vascular branches – the brachiocephalic trunk, the left common carotid and the left subclavian arteries depart from the aortic arch.
According to autopsies, aneurysms of the thoracic aorta occur in 0.9-1.1% of cases, 3–7 times more often in men. Of these, the aortic arch aneurysm accounts for about 18.9% of cases. Mortality within 3 years after the detection of the aneurysm is 35%, and after 5 years it reaches 54-65%.
Causes of Aortic Aneurysm
The causes and mechanisms of development of aneurysms of the aortic arch do not differ from those with other aneurysms localizations. Congenital risk factors include hereditary diseases of the connective tissue that contribute to weakness of the aortic wall, such as Marfan’s disease, fibrous dysplasia, Ehlers-Danlos syndrome, cystic medial necrosis, inborn tortuosity of the aortic arch, coarctation, etc. and non-specific aortitis with rheumatism, syphilis, tuberculosis, mycoses, bacterial infection, Takayasu’s disease; non-inflammatory degenerative processes (atherosclerosis, etc.).
With the development of vascular surgery, aneurysm of the aortic arch, caused by defects of the graft and suture material, including post-stenotic aneurysms, is increasingly common. As a result of chest injuries, post-traumatic aortic arch aneurysms can form. From the moment of injury to the development of an aortic arch aneurysm, a long period can pass (from several months to 20 years).
Persistent arterial hypertension contributes to the weakening of the aortic wall tone and the formation of the aneurysmal sac. Independent mechanisms for the development of aortic arch aneurysms are considered to be over 60 years of age, male gender, the presence of aneurysm in family members. For aneurysms of inflammatory origin are characterized by periaortitis, thickening of the outer shell and the intimal aortic layer, productive inflammation with the destruction of the elastic and muscular framework of the aortic wall.
In the pathogenesis of aortic arch aneurysms, in addition to inflammatory and degenerative processes, hemodynamic and mechanical factors play a role. Features of hemodynamics in the thoracic aorta are in the high speed of blood flow, the steepness of the pulse wave and its shape. In addition, the thoracic aorta has the most functionally tense segments – the root, the isthmus and the diaphragm. Therefore, an increase in blood pressure or mechanical trauma easily leads to tearing of the inner lining of the aortic wall with the formation of a subintimal hematoma, and subsequently aneurysm.
Symptoms of Aortic Aneurysm
Aneurysm of the aortic arch of medium and large size leads to compression of adjacent anatomical structures, which determines the characteristics of the clinical course of pathology. The pressure of the aneurysmal sac on the surrounding tissues and the stretching of the aortic nerve plexus is accompanied by a pulsation in the chest, chest pain, radiating to the neck, shoulder, back. As a rule, the pains have a persistent, burning character and are not stopped by the intake of nitrates.
Dry, agonizing cough, shortness of breath and stenotic breathing appear during compression of the bronchi and trachea. When the aortic arch aneurysm is compressed, the larynx paresis occurs (dysphonia and hoarseness); compression of the esophagus is accompanied by symptoms of dysphagia. The development of the superior vena cava syndrome is characterized by headaches, swelling of the face and upper torso, asphyxiation, cyanosis, swelling of the veins of the neck, and scleral hyperemia.
When squeezing sympathetic ways develops Horner’s syndrome, manifested in the constriction of the pupils, partial ptosis of the eyelids, anhidrosis, etc.
In some cases, an aortic arch aneurysm is recognized only in connection with its rupture. This complication may be accompanied by hemorrhage in the mediastinum, hemothorax, bleeding into the esophagus, hemoptysis and pulmonary hemorrhage. Massive bleeding is accompanied by sharp pain, pallor, loss of consciousness, thready pulse and, as a rule, quickly leads to a fatal outcome. In addition to rupture, an aortic arch aneurysm may be complicated by thromboembolism of the arteries of the greater circulation, including cerebral, leading to the development of a stroke.
Diagnosis of Aortic Aneurysm
Diagnosis of an aortic arch aneurysm is based on clinical data, the results of X-ray, aortography, ultrasound angiography, CT and MRI.
During external examination, attention can be paid to the increased pulsation of the aortic arch in the jugular notch, as well as the bulging of the aneurysmal sac in the sternum area visible to the eye. The fact of a history of syphilis, chest injuries, nonspecific aortoarteritis, etc. is important. Suspecting an aortic arch aneurysm in some cases allows the appearance of patients with Marfan syndrome: tall, thin, long arms, arachnodactyly, funnel chest, kyphoscoliosis, increased weakness of the ligamentous apparatus of the joints.
Polyposition chest radiography reveals the shadow of the aortic arch and the expansion of the vascular bundle. Calcification of the walls of the aneurysm is often determined. X-ray of the esophagus and stomach allows detecting the displacement of the esophagus and cardia of the stomach. Invasive radiopaque aortography is used mainly to assess blood flow in the aortic branches.
The leading role in the recognition of aortic arch aneurysms belongs to ultrasound examination: echocardiography (transthoracic, transesophageal echoCG), USDG and duplex scanning of the thoracic aorta. This method is indispensable for determining the diameter of the aorta, the presence of dissection, blood clots in the aneurysmal sac.
CT scan (MSCT) of the thoracic aorta with contrast allows to clearly reveal the sacculate or spindle-like expansion of the aortic lumen, the presence of thrombotic masses, dissection, para-aortic hematoma, calcification foci. The differential diagnosis of an aortic arch aneurysm should be carried out with tumors of the lungs and mediastinum.
Aortic Aneurysm Prediction
In case of refusal of treatment, the prognosis for aortic arch aneurysm is unfavorable: about 60% of patients die within 3-5 years from rupture of aneurysm, coronary artery disease, stroke.
The prognosis is aggravated when the aneurysm is larger than 6 cm, concomitant hypertension, post-traumatic genesis of the aortic arch aneurysm.