Aortic aneurysm is a limited intraluminal dilatation of the aortic vessel localized in any of its anatomical parts and characterized by the persistence of clinical manifestations. A separate nosological unit in the international cardiological classification is exfoliating an aneurysm of the aorta, which is only a complication of the underlying pathology that occurs with its long flow or traumatic injury.
There are many clinical, etiopathogenetic and morphological classifications of aortic aneurysm, however, the basic criterion for practicing cardiologists and cardiac surgeons is the separation according to the principle of localization of aneurysmal enlargement.
Causes of aortic aneurysm
For a long time, the only etiopathogenetic factor provoking the development of aortic aneurysm was considered atherosclerotic vascular lesion, but at present there are many pathogenetic theories of the formation of aneurysmal aorta expansion.
An aortic aneurysm of the heart most often develops as a result of the "defectiveness" of the medial wall of the vascular wall, which can be of an innate nature, and under the influence of an elevated pressure gradient there is a local bulging of the aortic wall on the affected area.
The latest scientific studies devoted to the pathogenesis of the development of aortic aneurysm have proved the negative effect of nonspecific degenerative processes occurring in the middle shell of the vascular wall, which in cardiosurgery is designated by the term "medionecrosis". These pathological changes in the vascular wall of the aorta are observed in persons suffering from generalized pathology of connective tissue, which is observed in Marfan's disease .
Acquired aortic aneurysm is most often a consequence of an inflammatory disease of the aortic vessel of an infectious and immune nature, which is observed, for example, with syphilis . The principal difference between an aortic aneurysm and an aneurysmal enlargement of other vessels is that the aneurysmal sac in the projection of the aorta consists exclusively of the fibrous component and there are absolutely no signs of laminar blood flow. In connection with the fact that with aneurysm of the aorta in the lumen of the aneurysmal sac massive thrombotic layers are formed, even with angiographic contrast study it is not possible to reliably estimate the metric parameters of the aneurysm.
Fortunately, recently aneurysms appeared as a complication of surgical intervention on the aorta, but aneurysm of the abdominal aorta most often has posttraumatic origin, which is observed with closed blunt trauma of the abdominal cavity.
Symptoms of aortic aneurysm
The specificity of the clinical symptom complex, as well as the intensity of manifestation of these or other symptoms, directly depends on the localization of the aneurysmal lesion of the vessel, as well as on the size of the aneurysmal sac itself. Prolonged course of an aneurysm inevitably provokes an increase in its metric parameters, which significantly increases the risk of its rupture into nearby hollow organs and cavities (pleural, peritoneal, pericardial). The rupture of the aortic aneurysm in the projection of the pulmonary trunk contributes to the development of aorto-pulmonary shunts, which entail significant disturbances of cardiohemodynamics.
With an aneurysm of the aortic sinuses, conditions are created for the development of aortic valve failure and concomitant intraluminal narrowing of one or more coronary arteries. Clinical manifestations of an aneurysm of this localization in the form of an increase in liver size, swelling of the cervical veins and the development of generalized edematous syndrome are caused by the compression effect of the aneurysm on the pulmonary trunk and the right heart. In a situation where the patient has an aneurysm of aortic sinuses of gigantic proportions, the compression effect on the pulmonary trunk can be fatal.
Aneurysm of the ascending aorta of the patient is disturbed by prolonged chest pains of blunt character with severe respiratory disorders in the form of progressive dyspnea. Aneurysm of the ascending aorta of large size inevitably provokes the development of atrophic changes in the bone tissue of the anterior segments of the ribs and sternum and the appearance of abnormal pulsation along the right parasternal line at the level of the second intercostal space. The appearance of a patient suffering from an aneurysm of the ascending aorta, swelling of the cervical veins and swelling of the extremities indicates a compression effect on the upper vena cava.
Aneurysm, localized in the projection of the aortic arch, is most often manifested by respiratory disorders of varying degrees of intensity, the occurrence of which is due to the compression effect on the trachea and bronchi of a large caliber. With compression of the left main bronchus, segmental or lobar atelectasis develops. Occurrence of complaints of hoarseness in the patient, constant cough without sputum discharge, attacks of suffocation should be regarded as compression by an aneurysmal sac of the lower-nerve nerve. With the breakthrough of the aortic arch aneurysm, the esophagus develops classical symptomatology of esophageal bleeding, in need of immediate medical intervention.
With an aortic aneurysm localized in the descending section of large sizes, the patient is symptomatic of a neurological profile that simulates other diseases and makes it difficult to diagnose an aneurysm in time. In this pathology, patients pay attention to the pronounced pain syndrome in the projection of the spine and the violation of all types of sensitivity. With the squeezing effect of an aneurysm on the pulmonary parenchyma, conditions are created for the development of hypoventilation pneumonia, prone to the formation of lung atelectasis. Compression of the lumen of the esophagus is manifested by the difficulty of promoting the food lump (dysphagia). Prolonged application of an aneurysmal sac to the esophagus wall can form a perforation of the esophagus, which is accompanied by the development of submissive esophageal bleeding.
Aneurysm of the thoracic aorta, as well as the thoracoabdominal section, is most often inflammatory in syphilitic lesions. A characteristic manifestation of an aneurysm of this localization is the appearance of a pronounced pain syndrome in the projection of epigastrium, caused by a violation of the blood supply to the abdominal cavity, resulting from compression of the lumen of the upper barbial artery.
The development of complications in aneurysm of the aorta can be observed both in the complete absence of therapeutic measures, and in the postoperative period. With the patient's aneurysm in the ascending aorta, a cardiac defect is formed in the form of aortic valve insufficiency during prolonged course of the aorta, and signs of heart failure due to circulatory disorders along the coronary arteries develop. The most common complication of an aneurysm is its rupture and development of massive bleeding. The volume of blood loss with aortic rupture is very large, therefore for this pathology the rapid development of posthemorrhagic shock is characteristic.
Dissecting aortic aneurysm
The dissecting type of thoracic aortic aneurysm is formed, as a rule, against the background of atherosclerotic lesion of the aortic vessel, combined with a traumatic effect on the chest of arterial hypertension with high blood pressure figures. The initial signs of separation are the detachment of intima of the aorta with the subsequent development of intra-wall hematoma. Thus, the pathomorphological substrate of the exfoliating aortic aneurysm is the intramural hematoma that separates the aortic wall into layers (inner and outer). In a situation where the aortic wall stratification occurs all along, the effect of a "vessel in the lumen of the vessel" is formed.
There are three main pathogenetic variants of the development of aneurysmal stratification. With acute dissection of the aortic aneurysm, the highest likelihood of developing a lethal outcome in the first 4 hours. The duration of the development of aneurysmal dissection in subacute flow ranges from five days to one month. The chronic course of the exfoliating aneurysm is extremely rare and is characterized by a slowly progressive development of damage to the walls of the aneurysm.
In the acute course of the dissecting aortic aneurysm, the patient develops a vivid clinical symptomatology in the form of a sudden intense pain syndrome in the retrosternal region radiating into the interlobar region and the upper humeral girdle. There is a pathognomonic symptom of the movement of pain in the projection of the lumbar, epigastric and peripodic region, indicating an increase in stratification and an increase in intra-wall hematoma. The nature of the retrosternal pain is predominantly paroxysmal, which fundamentally distinguishes the exfoliating aneurysm from an attack of angina pectoris.
With an objective examination of the patient, it is possible to detect abnormal pulsation, auscultation of coarse systolic noise at the aortic listening point with maximum auscultation in the projection of aneurysmal enlargement. An indirect sign of the aortic aneurysm stratification is a sharp increase in the numbers of arterial pressure, followed by a sharp decrease in its indices. In order to verify the diagnosis, the patient is urgently required to perform an overview radiograph of the thoracic cavity organs, and if necessary, an angiography.
Until an accurate diagnosis is established, the patient needs to provide emergency medical care, consisting in carrying out adequate anti-shocks, analgesic measures. Anti-shock and analgesic measures imply the use of 0.005% solution of Fentanyl in a dose of 1 ml together with 0.25% solution of droperidol in a dose of 2 ml intravenously. At the prehospital stage with a delaminating aneurysm, in the absence of neuroleptanalgic drugs, 1% Morphine solution in a dose of 1 ml with 1% solution of Dimedrol in a dose of 2 ml should be intravenously administered to the patient. Intramuscular injection of 0.1% solution of Anaprilin in a dose of 1 ml is expedient only in the case of an available increase in the figures of arterial pressure with complete absence of signs of bronchospastic syndrome. After providing primary medication for a patient with a dissecting aortic aneurysm, it is necessary to be hospitalized in a cardiosurgical hospital.
Aneurysm of the abdominal aorta
Among cardiac surgeons, there is an opinion that the genetic predisposition is most important for the development of an aneurysm localized in the abdominal aorta. In addition, the aneurysm of the abdominal aorta can reach critically large sizes exceeding the index of 80 mm, which significantly increases the risk of developing not a delamination, but a rupture of the vessel wall. This localization of the aneurysm has the highest rate of development of complications in the form of rupture of the vascular wall, and the death rate is 60%.
As with other localization of the aortic aneurysm, an aneurysmal dilatation of the abdominal part most often develops in the projection of the atherosclerotically altered portion of the vascular wall. The second place in the structure of the etiological factors provoking the development of an aneurysm occupies a traumatic effect on the abdominal cavity and bone and traumatic injuries of the spine. Syphilitic aneurysms of this localization are extremely rare and are the exception to the rule.
The earliest sign of an aneurysm localized in the abdominal aorta is the patient's perception of abnormal pulsation in the abdominal cavity. For an aortic aneurysm of this localization, the development of a typical pain syndrome is not typical, but some patients may note a feeling of discomfort in the back, which decreases with the movement of the trunk.
The appearance of a pronounced pain syndrome in the upper half of the abdomen and back is the earliest clinical criterion for the development of aneurysm rupture. This pathology is characterized by a lightning-fast increase in the manifestations of shock caused by massive bleeding into the abdominal cavity. In the absence of timely surgical intervention, exfoliating aneurysm of the abdominal aorta in a short time provokes the development of a lethal outcome.
Diagnosis of aortic aneurysm
Typical clinical signs for aortic aneurysm of any localization appear only in the stage of compression effect on nearby internal organs, therefore it is not possible to rely only on a clinical picture when establishing a diagnosis. Very often, the verification of aortic aneurysm occurs at the time of routine examination of the patient using routine screening instrumental techniques. With large aneurysmal enlargement and typical aneurysmal localization, an experienced cardiologist can detect pathological objective symptoms already at the stage of a primary examination of the patient, but the final verification of the diagnosis is possible only after using specific instrumental imaging techniques.
Even during the routine X-ray examination, in most cases, it is possible to correctly interpret the abnormal picture of the aneurysm, which is visualized as a significant enlargement of the aorta that displaces the structures of the mediastinal top floor in the opposite direction. In order to clarify the localization of an aneurysm, it is advisable for a patient to perform an X-ray of the thoracic cavity with oral contrasting of the esophagus. A prolonged course of the aortic aneurysm necessarily provokes the deposition of calcium salts on its walls, which can be visualized on a roentgenogram in a polypositional examination. In a situation where an aneurysm localized in the abdominal aorta has large parameters with an overview of the fluoroscopy of the abdominal cavity, it is possible to visualize the lumbar vertebrae, as well as the aneurysmal expansion itself, with pronounced calcification of the aortic walls.
Ultrasound examination refers to the most common method of visualization of an aneurysm, especially the abdominal aorta. Echographic signs of an aneurysm is a significant expansion of the aorta lumen throughout the vessel, as well as an atherosclerotic lesion of the vascular wall.
To assess the condition of the walls of an aneurysmal sac and the available signs of aneurysmal dissection, a computed tomography is recommended for the patient. However, the most reliable in the diagnosis of aortic aneurysm is angiography, which allows the most accurate determination of the localization of the aneurysmal sac, its extent and indications for surgical intervention.
Treatment of aortic aneurysm
In all situations, verification of the diagnosis of "aortic aneurysm" is the basis for the use of surgical intervention, however, there is a fairly narrow range of criteria that are an indisputable argument in deciding the question of surgical treatment. For example, critical parameters of aneurysmal enlargement, which are more than 5 cm, are an absolute criterion for operative aortic resection. In addition, aneurysms of different localization with all signs of a possible aortic rupture and an increased risk of developing thromboembolic complications are subject to prompt removal. Also, an indisputable indication for performing an operative intervention is the rapid progressive growth of an aneurysmal sac, exceeding 5 mm in six months.
It should be taken into account that the border sizes of the aortic aneurysm can proceed with severe hemodynamic disorders requiring correction, therefore, in the absence of therapeutic measures of the conservative and surgical plan, this pathology has an extremely unfavorable course and prognosis for the patient. A sudden lethal outcome is usually a consequence of massive bleeding and development of hemorrhagic shock, which occurs when the aortic vessel wall is ruptured, but one should not forget about the risks of lethal outcome caused by the development of decompensated heart failure , which has a long course and is threatening for the patient's life condition.
Currently, the successful introduction into the surgical practice of the cardiac profile of the newest methods of treating aortic aneurysm, allows improving the quality and life expectancy of persons suffering from this pathology. According to the world statistical data, the five-year survival rate of patients in the postoperative period reaches 80%, which is an indicator of the effectiveness and expediency of surgical treatment of aortic aneurysm.
In a situation where the patient has contraindications to surgical intervention, for example, elderly age or the presence of concomitant pathology in the stage of decompensation, the use of maintenance medication is recommended, based on drugs of the antihypertensive group of beta-blockers (Obsidan at a daily dose of 80 mg orally). As preparations of the etiopathogenetic orientation of the action, cholesterol-reducing drugs should be preferred, as prevention of progression of atherosclerotic heart disease and blood vessels (Atorvastatin in a daily dose of 20 mg for at least two months). Of course, lifestyle modification measures are a good prevention of further progression of diseases, which are the backdrop for the development of an aneurysm.
Operation with aortic aneurysm
The volume and technique of surgical intervention primarily depend on the localization of aneurysmal enlargement. So, with the available aneurysm of the ascending aorta it is advisable to perform the operation through a median sternotomy. The initial stage of the surgical manual is the exposure of the aorta and its deenergia from the general circulation, for which a special clamp is applied at a distance of 20 mm from the neck of the aneurysmal sac. The excision of the saccular aneurysm should be complete, but above the place of application of the clamp it is necessary to preserve a site of unchanged vascular wall with a length of at least 10 mm. After excision of the aneurysm, the wound surface is closed deafly, and in case of a large defect, the technique of suturing the synthetic flap can be used.
With a spindle-shaped aneurysm of the ascending aorta, there is a diffuse intraluminal extension of a large extent, so surgical intervention is performed under the condition of using the device of artificial circulation. Immediate exposure of the aorta makes it possible to impose a transverse clamp on the aorta above the projection of the divergence from it of the brachycephalic trunk. The aneurysmal sac is opened at the same time as the insertion of special cannulas into the coronary arteries in order to improve coronary perfusion. Due to the fact that the spindle aneurysm occupies a large aortic segment, surgical intervention implies aortic resection at a large extent with subsequent replacement of the defect with an allograft.
In a situation where the patient has complications of aortic aneurysm in the form of aortic valve failure, operative intervention is carried out in stages. Initially, the aortic valve is replaced, followed by aortic resection and allograft application.
Surgical treatment of the aneurysm of the arch of the aorta is performed only under conditions of artificial circulation and consists in applying a clamp to the arch of the aorta in order to turn off the aortic arch along with the outgoing arteries from the circulation. Operative benefit in this case consists in resection of the altered aorta site with subsequent replacement by the allograft.
The operation to remove the aortic aneurysm localized in the projection of its descending department is performed with partial use of the artificial circulation apparatus, while the vessels supplying blood to the upper half of the trunk are not switched off from the circulation. Operative access for resection is left-sided thoracotomy with subsequent opening of the pericardial cavity. The application of clamps on the aorta must be carried out in the transverse direction. Resection of the aneurysmally altered aorta site and subsequent stitching of the allograft is made to the remaining sections of the vascular wall, after which it is necessary to remove the clamps.
The surgical intervention in the dissecting aneurysm of the aortic vessel is the absolute criterion for the surgical intervention through the median sternotomy. Most often, resection of the altered enlarged aortic site is accompanied by the replacement of the aortic valve by an artificial valve.
With thoraco-abdominal aneurysm, thoracotomy with rib dissection and dissection of the dome of the diaphragm to the aortic level is the most favorable access, after which the abdominal organs move to access the aneurysmal retroperitoneal expansion. With the help of the allograft, the shunt is formed, after which the arterial branches leaving the aorta are anastomosed to the prosthesis.
? Aortic aneurysm - which doctor will help ? If you have or suspect aortic aneurysm, you should immediately seek advice from such doctors as a cardiologist and a cardiac surgeon.