Aortic dissection (old name – aneurysma dissecans) is a serious, life-threatening condition in which the inner layer of the aorta tears. Blood from the lumen (cavity) of the aorta rushes between the layers of the vessel wall, splits them and can tear the wall completely. An aortic rupture is a complete tear through all three layers of the aorta, resulting in a massive, fatal hemorrhage. Blood bursts through the hole into the surrounding body cavity. In rare cases (in very lucky patients) the secondary tear is inward, back towards the aortic cavity. Then hemorrhage does not occur, and blood through the aorta begins to flow through the two cavities – the primary (physiological) and secondary (pathological) lumen. In cross-section, such an aorta has two cavities and resembles the number 8.
This severe disease occurs more often in people over the age of 45, but has also been described at young ages, including in a 12-month-old child. The male gender is more affected.
Causes of aortic dissection
The main cause of aortic dissection is arterial hypertension. In recent years, due to an increase in the number of patients with high blood pressure, the frequency of aortic dissection has significantly increased. Arterial hypertension (high blood pressure) accompanies aortic dissection in 85% of cases and plays an important role in its occurrence. Another cause of aortic dissection is prior aortic medianecrosis (death of muscle cells in the wall of the aorta) or the disease atherosclerosis.
During dissection due to atherosclerosis, the blood invades the wall of the aorta through an atherosclerotic
plaque, 4-5 cm from the beginning of the vessel, since the pressure is the highest in this part of the aorta. Having got between the layers of the aortic wall, the blood splits it quickly, and this can spread along the entire length of the vessel, and also cover the entire circumference of the wall.
In cases where the initial, intrapericardial part of the aorta is torn, blood pours into the pericardial sac and hemopericardium (cardiac tamponade) occurs. This deadly condition also develops as a complication of the rupture of the myocardium during a heart attack – Rupture of the heart.
Symptoms of aortic dissection
The beginning is dramatic – sharp pain in the chest and epigastrium (upper part of the abdomen). The pain can also spread to the back, in the lumbar (waist) and abdominal (stomach) areas. In strength, the pain resembles that of a myocardial infarction. In almost 90% of cases, the shock state accompanies the onset of the disease. Spread to the carotid, renal and mesenteric arteries can lead to seizures, convulsions, coma, hemiplegia (immobility of half the body), hematuria (blood in the urine). When the coronary arteries are affected, signs of a myocardial infarction appear in the ECG (electrocardiogram), and then the exact diagnosis becomes extremely difficult. Arterial pressure in aortic dissection is initially lowered, but may sometimes remain permanently elevated. Differences in the pulse wave are found in individual limbs. On the blood side, there is leukocytosis (increase in leukocytes in the blood) with progressive anemia. The diagnosis of dissection of the aorta is made with imaging studies – echocardiogram, computed tomography (CT) scan, – magnetic resonance imaging – MRI. A chest X-ray can also be informative and show the enlarged aorta, sometimes with the characteristic double contours.
Diseases with similar symptoms as aortic dissection are myocardial infarction, renal infarction, mesenteric thrombosis, massive pulmonary thromboembolism, acute surgical abdomen.
Treatment of aortic dissection
Treatment for aortic dissection requires emergency surgery. A portion of the damaged section of the aorta is removed and a synthetic fabric tube (graft) is sewn in its place.
In marked arterial hypertension, medications are used that lower blood pressure in order to prevent rupture (tearing) of the aorta. Despite treatment, the prognosis remains poor, with high mortality.