Tag Archives: aortic aneurysm

What Is Aortic dissection

What is aortic dissection? An aortic dissection is a potentially fatal condition in which, through a tear in the inner layer of the aortic wall, blood enters between the middle and outer layers separating (or dissecting) them.

  • Deterioration of the arterial wall due to high blood pressure is the most common reason for aortic dissections.
  • A severe pain appearing suddenly across the chest and at the back may indicate an aortic dissection.
  • X-rays and CT scans help with diagnosis and assessment of the extent and location of the damage.
  • Antihypertensive drugs and surgical repairs constitute the treatment.

 Blood leaking out through a tear in the inner wall of the aorta, results in the separation or dissection of the middle and outer layers, forming a pocket of blood there. Men are 3 times more prone to this condition, which usually occurs in the age group of 40 to 70. While its occurrence is less common in Asians; blacks, especially African- Americans are predisposed to this condition.

Deterioration of the walls of the aorta due to high blood pressure is the most common cause of aortic dissection, accounting for two thirds of the cases. Connective tissue disorders, especially the inherited condition called Marfan syndrome, predispose people to aortic dissection. Patent ductus arteriosus and coarctation of aorta and aortic valve defects are some of the congenital abnormalities that may cause an aortic dissection. Atherosclerosis and severe injury to chest also may be a cause. Accidental injury during a catheterization procedure such as angiography or other surgical procedures also may result in aortic dissection.

Symptoms

Severe ripping pain appearing suddenly across the chest and sometimes high up at the back is the symptom of aortic dissection. The pain also spreads along with the extension of the dissection.

Blockages can occur at the branching of the arteries when the dissection reaches there, cutting off blood supply to the different areas supplied by those arteries. When renal arteries are affected, it results in pain in the lower back area. Blockage in spinal arteries may cause freezing of limbs or tingling sensation in them. Abdominal pain results from blockage in the mesentery arteries which supply to the intestines. Heart attack and stroke are the outcomes of blocks in coronary and cerebral arteries respectively.

A leaking dissection causes accumulation of blood in the chest, which leads to pericardial effusion that may steadily worsen to cause cardiac tamponade. This potentially fatal condition requires immediate intervention.

Many of the symptoms appearing due to aortic dissection may resemble symptoms of other conditions, but there are certain symptoms which are characteristic of this particular condition. So, doctors can often diagnose an aortic dissection from those symptoms. Pulse may become undetectable or decreased in the limbs, in two thirds of cases. When dissection extends towards the heart, a stethoscope can detect a distinct murmur.

Aortic dissection can be detected by chest x-rays which shows an enlargement in the aorta but it cannot be considered as a foolproof confirmation. A trans-esophageal echocardiography with the ultrasound probe inserted into the esophagus, can detect dissections, especially in the first part of the aorta. But a CT scan is the ideal test, to detect the location and assess the extent of the dissection when it is done after the injection of a radio opaque dye.

Prognosis and Treatment

Prognosis is poor for people who do not get the right treatment; three fourths of them succumbing to it within two weeks. The death may be caused either due to the issues directly related to the dissection or due to other disorders precipitated or worsened by the dissection.  About 40% of those who get treatment, if they survive the first two weeks, have a good prognosis of extended life of up to ten years. The other 60% may not live beyond five years even with continued medication. People who have dissection in parts of aorta farther away from the heart have a better prognosis, than those who have aortic dissections much closer to the heart.

Drug treatment is started as soon as the patients are admitted in the intensive care unit for continuous monitoring, since aortic dissection can become suddenly fatal. A beta blocker and nitroprusside are administered intravenously to lower blood pressure and heart rate to the minimum possible levels needed to maintain life. In the meantime, doctors assess the need and suitability of surgical options.

For the part of aorta immediately after its emergence from the heart, surgery is the usual option considered by doctors. Drug therapy is initiated for dissections appearing in areas of the aortic artery further away from heart. But, if there is a leak in the artery causing internal bleeding, it has to be repaired surgically. If there is progression in the dissection or if blood supply to the limbs or important internal organs is compromised, immediate surgery may become necessary. For people with Marfan syndrome, doctors do not wait and watch, and surgery is always recommended to prevent avoidable emergencies. Surgery of the areas away from heart is riskier than the surgeries for dissections much more closer to the heart, the risk for the latter being around 15%.

Part of the affected artery is removed and the rest is repaired by closing the false channel that had developed due to dissection. Using a synthetic graft which provides strength and structural support, the walls of the aorta are reconstructed. The aortic valve is either repaired or replaced, if there is valve dysfunction and regurgitation. This surgery is time consuming, extending up to 6 hours. Prolonged hospital stay of over a week is also required. Endovascular stent grafting is a newer option, in which a catheter threaded up the femoral artery, carries a collapsible stent to the location of the dissection. The stent is enlarged at the site to repair the damaged aorta. It usually gets over in two to four hours and hospital stay is also reduced to less than three days.

Drugs to keep the blood pressure low, is an integral part of treatment, even after surgical correction of aortic dissections, as it helps to lower the stress inflicted on the walls of the aorta. An ACE inhibitor, in addition to one of the drugs belonging to either calcium channel blockers or beta-blockers, is taken for life. People with atherosclerosis are given anti-cholesterol medication and are advised to make suitable diet modifications.

Patients who have undergone surgical repair of dissections should be monitored at regular intervals to detect complications. Recurrence of dissection and formation of aneurisms, which may result in aortic valve dysfunction and regurgitation, are possible complications which should be treated promptly.

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What Is A Thoracic Aortic Aneurysm (TAA)

Aneurysms, developing in the thoracic aorta, which passes through the upper region of the trunk or thorax, are called thoracic aortic aneurysms.

  • Pain, wheezing and coughing may result from thoracic aortic aneurysms, or they may be even asymptomatic.
  • Severe pain felt at the upper back and spreading down in to the abdominal region may indicate the rupture of a thoracic aortic aneurysm.
  • Presence of thoracic aortic aneurysms, when accidentally discovered, can be confirmed by further tests such as x-ray, CT scan etc.
  •  Surgical repair of the aneurysms is undertaken to prevent rupture.

With the more frequent use of CT scan for diagnostic purposes of other chest ailments, thoracic aortic aneurysms are getting discovered more often, making preemptive surgical repair possible. Cystic medial necrosis is a condition in which, the aortic walls degenerate and the emerging region of the aorta enlarges resulting in aortic valve dysfunction, including aortic valve regurgitation. People with Marfan syndrome are found to be more prone to this type of aneurysm. High blood pressure is the only other identifiable cause of this condition, in people without Marfan syndrome. Occasionally, syphilis infection is found to cause aneurysms in the part of aorta nearest to the heart. Blunt injuries to the chest are also found to be a risk factor for aneurysms of the thoracic aorta.

Symptoms Of  Thoracic Aortic Aneurysm

Without causing any apparent symptoms or discomfort, some thoracic aortic aneurysms grow in size within the chest, till they start exerting pressure on the other internal structures. When large aneurysms exert pressure on the trachea, esophagus and larynx; symptoms such as coughing, wheezing, difficulty in swallowing food and hoarseness of voice start developing. Pain may be felt high up in the back too. Pressure on some nerves in the chest may result in Homer’s syndrome that has symptoms which appear peculiarly on one side of the face only, such as drooping of eyelid, constriction of pupil or sweating of face. Displaced wind pipe and pulsations in the chest may also result from an anurism.

A rupture results in the typical piercing and continuous pain, starting high up in the back and progressing down into the abdomen. Pain in the chest and down the arms, similar to a heart attack, may also be present. Loss of blood due to internal bleeding causes shock and finally death.

Treatment Of  Thoracic Aortic Aneurysm

Pre emptive and scheduled surgery before a rupture, is the ideal solution to thoracic aortic aneurysms. Drugs to lower blood pressure and slow down the heart rate are given to minimize the risk of rupture. Either open chest surgery or endovascular stent placement is done, to repair aneurysms more than 2 inches wide. It entails a hospital stay of up to a week or more and carries a risk of death between five to ten percent. People with Marfan syndrome are subjected to surgery much earlier, considering the additional risk of early rupture. In spite of the high risk rate, surgical repair before rupture is always advisable, as the risk of death during surgery following a rupture is around 50%, even with immediate surgical intervention. Ruptured thoracic aortic aneurysms are 100% fatal, if they are not treated.

Aneurysms Of Smaller Arteries

Occasionally, coronary arteries of the heart and femoral arteries of the thigh and more commonly, popliteal arteries running at the back of the knee, also develop aneurysms but the incidence is more common among older people. The carotid arteries of the neck can also have aneurysms, but it is very rare. Weakening of the arterial walls, due to atherosclerosis or due to congenital defects, is the main cause of these aneurysms. Mechanical injuries to the arteries, bacterial and fungal infections which originate in the valves and spread to the arterial walls, are also found to be responsible for aneurysms.

Aneurysms in the femoral, coronary and popliteal arteries are generally asymptomatic and ruptures also occur rarely. But risk of clot formation and resultant emboli blocking smaller arteries are much higher. Emboli originating in the carotid aneurysms can cause a block in the smaller arteries in the brain, resulting in stroke.

When a pulsating mass is detected during physical examination, further tests such as ultrasound scan and CT scan are done, to confirm the aneurysms and to determine their size and progress. Surgical repair of aneurysms 1 inch or more in size are usually done, especially in the case of popliteal aneurysms.

Cerebral Aneurysm occurs in the cerebral arteries that supply blood in the brain. When a cerebral Aneurysm ruptures, it causes intracerebral hemorrhage or bleeding in the brain which leads to stroke. Cerebral aneurysms are usually small but they are dangerous due to their proximity to the brain and their treatment is also different. Infections in the cerebral aneurysms are promptly treated and surgical repair is done, because of the extreme danger they pose.

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What Is An Abdominal Aortic Aneurysm (AAA)

When aneurysms occur in the abdominal aorta which runs through the abdominal region, they are called abdominal aortic Aneurysms.

  • Pulsations can be felt at the site of an aneurysm.
  • When aneurysms rupture, terrible pain may result.
  • Aneurysms are accidentally detected when a person undergoes physical examination or diagnostic tests for some other reason.
  • Antihypertensive drugs are given to reduce the pressure on the arterial wall and to prevent the aneurysm from worsening.
  • Large aneurysms have to be surgically repaired.

Men in the age group of 50 to 80 and those with high blood pressure are more prone to abdominal aortic aneurysms. People with a family history of the disease and those who smoke are also at greater risk. Abdominal aneurysms rupture in one fifths of cases, resulting in a potentially fatal situation.

Symptoms Of Abdominal Aortic Aneurysm

Abdominal aortic aneurysms are usually asymptomatic in most people, but some may feel pulsations in the abdomen. Pain due to a worsening aneurysm is felt as a piercing pain deep down in the back, and leakage results in excruciating and continuous pain.

 Severe, unrelenting pain in the back and lower abdomen may be an indication of a ruptured aortic aneurysm. Pain and tenderness may be felt externally, over the location of the aneurysm. The rupture of an abdominal aortic aneurysm results in significant blood loss that leads to shock and eventually death, in most cases.

Diagnosis Of Abdominal Aortic Aneurysm

By the time pain due to aneurysm is felt by people, it may be too late. However, accidental discovery of aneurysm from an abdominal scan or X-ray, occasionally make early intervention possible, saving lives. A whooshing sound, called bruit, resulting from blood rushing by the bulge in the artery can be picked up by the stethoscope, when the doctor listens to the sounds from the mid abdominal area. A pulsation also can be felt. Aneurysms may be the cause of pain and tenderness when doctor presses on the abdomen and further investigations may be done. It is difficult to detect abdominal aneurysm in obese people through physical examination.

When there is calcification of the walls of the bulge, it may be detected in an x-ray, but that cannot be considered a conclusive evidence of the condition. Ultrasonography can give a better diagnosis of aneurysms in the abdomen and it can track their progress over a period of time. CT scan of the abdomen, with the injection of radio opaque dye, gives a very clear picture of the aneurysm but the high levels of radiation involved is a cause of concern. On the other hand, MRI scan does not have any risk of radiation but availability may be a problem.

Treatment Of Abdominal Aortic Aneurysm

Smaller aneurysms do not pose any risk of rupture, and people are treated with blood pressure lowering drugs only. They are advised to discontinue tobacco usage, which is known to aggravate aneurysms. Aneurysms less than 2 inches wide are tracked at regular intervals to watch their progress.

To prevent the rupture of aneurysms larger than 2 inches wide, surgical repair is attempted, unless the patient is not in a condition to withstand the surgery which may take 3 to 6 hours. There are two methods; both involve grafts. In the traditional method, a large vertical incision, extending from below the sternum to a point beyond the navel, is made. The graft is first stitched on to the aorta with the walls of the aneurysm wrapped around the graft. It is a long surgery extending up to 6 hours and is done under general anesthesia. More than a week of hospitalization also may be required. Endovascular stent grafting is a newer, less invasive surgery, usually performed under epidural anesthesia which numbs the person from waist down. A guide wire is inserted through small cut in the groin and threaded up the femoral artery and into the aorta, to reach the location of the aneurysm. It is followed by a catheter with a stent graft which is guided to the location of the aneurysm and fixed inside it. The stent is a small collapsible tube made of a mesh and on reaching the site; it is opened up to fit the inside of the aorta very snugly, providing strength and support to the wall of the aorta. Usually, 2 to 5 hours are taken to complete the surgery and hospital stay is reduced to less than a week. The fatality from surgery is about 2 to 5%, but considering the almost cent percent risk of death from ruptured aneurysm; this may be a risk worth taking.

Immediate surgical intervention, either through open surgery or by endovascular stent graft, is necessary to handle an abdominal aortic aneurysm that has already ruptured or is on the verge of rupture. There is a risk of death of 50% during the surgical repair of a ruptured aneurysm; endovascular stent graft placement reduces it by almost half. There is a high probability of shock developing due to excessive blood loss; it can cause kidney failure, in which case, the prognosis becomes extremely poor. Fatality is 100%, if ruptured aneurysm is left untreated.

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Definition Of Aneurysms and Dissections

Aneurysms and dissections are two types of potentially fatal disorders of the aorta. In aneurysm, a weak area in the wall of the aorta bulges out. In dissections, the layers of the arterial wall get separated. These disorders gradually develop over the years, but they are fatal when they occur. Aneurysms are not restricted to the aortic artery alone; they develop in smaller arteries too.

Before going to details We need to know what is an aorta ? The Aorta, arising from the left ventricle, is the largest artery in the body, with a diameter of approximately one inch at its widest point. The oxygenated blood from the left ventricle is pumped into the aorta, from which it is carried to the different parts of the body by the smaller arteries, branching off from it at different points. After the arteries to the head and the hands have branched off, the aorta doubles up on itself forming an arch over the heart, and then goes down along the spine giving out branches to the left and right, till it reaches the pelvis. At the pelvis, it bifurcates into the two iliac arteries that go down the legs.

The force exerted on the walls of the aorta, by the pressure of the blood passing through it, causes ballooning out of the weak points in the wall. These bulges are called aneurysms. This ballooning out, further thins out the walls of the aneurysms, eventually resulting in their rupture. If the rupture is minor, it may only cause a leak which can induce people into getting medical help due to the pain it causes. A small tear can be surgically repaired without further incident. However, a large rupture causes severe uncontrollable internal bleeding which almost always results in death.

The abdominal aorta is the part that is most prone to Aneurysms accounting for nearly 75% of all aortic aneurysms. Thoracic aorta which passes through the chest area is the next common site of aneurysms. Popliteal arteries at the back of the knee, femoral arteries in the thigh, carotid and cerebral arteries which supply to the heart and brain respectively, also may have aneurysms. Aneurysms in older people are found where arteries branch, possibly because of the turbulent flow of blood hitting the arterial walls at these places, weakening them. Tube-like or fusiform aneurysms are more common than rounded saccular aneurysms.

Atherosclerosis, which weakens the walls of the aorta, is usually the underlying cause of aortic aneurysms. Aortitis, which is an inflammatory disease of the artery, infectious diseases like syphilis and mechanical injuries to the arteries are also reasons for developing aneurysms. People with Marfan syndrome, which is an inherited connective tissue disorder, have aneurysms in the first part of the aorta called the ascending aorta. High blood pressure and smoking are known risks of aneurysms.

Due to the sluggish blood flow within the aneurysms, the chances of blood clot formation are very high. Sometimes, the walls of the aneurysms may be lined by a layer of clotted blood. The risk of blood clots breaking away and travelling along the arteries as emboli and finally causing blockage in smaller arteries, is also quite high. Popliteal arteries with aneurysms are more susceptible to emboli formation. Calcification of the walls of aneurysm also occurs in many cases.

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