Aorta is the great blood vessel, the largest in the body, which receives blood from the heart to circulate to different parts of the body. Aorta can be involved in many disease conditions – the important ones are:
- Aortic Aneurysm
- Aortic Dissection
Aortic aneurysm involves the abnormal dilatation of the aortic wall. The common risk factors for formation of an aneurysm in aorta are raised blood pressure, smoking, genetic factors and a genre of diseases under the common term connective tissue diseases, such as Marfan syndrome.
Aortic aneurysm varies in its presentation, depending on the site of the aneurysmal formation. If it occurs in the chest, it can present with chest pain, breathing difficulty due to compression of respiratory airway, the trachea. When it occurs in the abdomen, it can present with pain in the central abdomen or back. As a grave complication, it can rupture into the abdominal space and result in death of the patient. The sluggish flow of the blood through the dilated segment can lead to clotting of blood and subsequent formation of thrombus, which is an aggregate of clotted blood. This can occlude blood supply to other parts of the body.
Investigations commonly employed are Chest X-ray, Echocardiography, MRI or CT imaging. These help in pinpointing the site of the aneurysm and can be valuable for deciding the intervention and for follow up. Treatment of aortic aneurysm can be either conservative or surgical. In the initial stages when the aneurysm is small, its rate of enlargement can be decreased by drugs such as propranolol. In symptomatic cases, surgical replacement of the dilated segment by using synthetic grafts, such as Dacron grafts are in practice. In this procedure, under general anaesthesia, the diseased segment is removed and the graft is installed which is stitched on to the two free ends.
Aorta is composed of three distinct layers. In dissection of aorta, a breach in the integrity of the aortic wall allows blood to burst into the middle layer, which is then split in two layers, creating a false lumen. The most important risk factor for dissection is raised blood pressure, others being atherosclerosis, aneurysms, coarctation of aorta, surgery, pregnancy, trauma, procedures like cardiac catheterization. Dissection occurs most commonly in males in their 6th or 7th decade of life, but can also occur in younger individuals with the above said risk factors.
Aortic dissection presents with severe ‘tearing’ chest pain and the patient most often falls unconscious. Depending on the site, it can present with myocardial infarction (heart attack), paralysis of lower limbs (paraplegia), acute abdominal pain, kidney failure etc.
Investigations useful are chest x-ray, echocardiography, MRI and CT imaging. Management of dissection involves two phases. In Initial stabilising phase, pain relief and decreasing raised blood pressure are the key interventions. Surgical intervention is the definitive mode of approach where the diseased segment of aorta is replaced by a Dacron graft. Newer modalities such as endoluminal repair can be done, which are procedures similar to cardiac catheterization, the advantage being minimal scar and stitching with early discharge.
Aortitis is inflammation of aorta. It can be due to infection of aorta or a non infectious etiology. Infections such as syphilis were the usual culprit, but the decrease in syphilis in the community has brought a fall in the incidence. Laboratory investigations such as VDRL (Venereal Disease Research Laboratory Test) or latest FTA-Abs test can be used for identifying syphilitic infection.
The other uncommon causes of Aortitis are autoimmune diseases which are caused by attacking of normal body tissue by antibodies directed against selt. Common diseases are Takayasu arteritis and Giant cell arteritis. Echocardiography, Doppler scan and chest X-ray can be useful investigations.