Types of Aneurysms - Case Study Example

? Aneurysms and al affiliation An Aneurysm is a localized or focal dilation in an artery and involves at least 50% increase over its normal diameter. For abdominal aorta, an increase of 3cm in diameter fits this description. (Pearce, 2011) .In many cases the dilation stretches out from a local area but it can also involve the whole circumference (Reed D, Reed C, Stemmermann and Hayashi, 1992). Aneurysms forms when blood pressure passes through a degraded or injured part of artery thus causing the vessel to bulge outward eventually forming a balloon like extension. Not all aneurysms are live threatening but when the vessel is over enlarged it may burst causing massive internal bleeding (“Aneurysms and dissection”, 2011).In normal situations, arteries are capable of withstanding normal blood pressure due to their thick walls. Dissection occurs when a split occurs in either one or more layers of the walls of artery. This splitting causes bleeding along and into layers of the artery wall (“What is aneurysm”, n.d). Incidence, mortality and morbidity Aneurysms affect 1 in every 20 people in most societies and are therefore a global health problem. It is approximated that about 30,000 people suffer from aneurysms in each year in USA (Khurana, and Spetzler, 2006) with abdominal aortic causing about 9000 deaths yearly. Most of abdominal aneurysms occur in 5th, 6th and 7th decades of life (Debakey, Crawford, Garrett, Beall, and Howell, 1965 ; Mastracci and Eagleton, 2011) .The 9000 deaths are inclusive of 1400-2800 deaths which occurs due to elective operation in an effort to prevent bursting (Lederle et al., 2002). Aneurysms rupture causes approximated mortalities of 80-90% and most of the patients die before they are hospitalised.These deaths are inclusive of pre, intra and post operative cases (Russo, 2006).For aortic aneurysms, it has been estimated that 13,000 Americans die annually and most of these deaths occur due to dissections or bursting of arteries (“What is aneurysm”, n.d).On the other hand, abdominal aortic aneurysms (AAA) are the 14th leading killer in USA (Russo, 2006). Risk factors and causes of aneurysms Any condition which leads to weakening of arteries walls predisposes a person to aneurysm. Other risk factors are smoking ,inborn abnormalities of connective tissue such as Ehler Donlos syndromes, congenital bicuspid valve abnormalities (Montgomery, Henderson, Ostrowsky, Karimmi and Hennein, 2010), high blood pressure, atherosclerosis which is characterized by building up of fatty plagues in the arteries, deep wounds, injuries, infections occurring in blood vessels, inherited diseases such as Malfan syndrome (a health condition which affects body’s connective tissue) which causes people to have very flexible joints and long bones (“Aneurysms and dissections”, 2011).Pregnancy has also been linked with the formation and bursting of aneurysms of the splenic artery which leads to the spleen (Reed et al, 1992). Aneurysms can also occur due to defective genes which play a critical role in maintaining the integrity of arterial wall which offers strength and elasticity to arteries. It has been thought that disruption of extracellar matrix of arterial wall plays a critical role in pathogenesis of aneurysms such as intracranial aneurysms (Kuivaniemi,Troup and Prockop, 1991).For those patients with intracranial aneurysms it has been observed that they have decreased level of arterial structural proteins (Kuivaniemi et al, 1991). People with defective genes have been shown to have abnormal aortic matrix proteins, insufficient inhibition of proteolysis or overactive proteolysis, lack of elastin and abnormal production of type 111collagen which is a structural component of aorta wall (Reed et al, 1992). Patients who have autosomal dominant polystic kidney disease (ADPKD) have also been shown to have risks of developing aneurysms. In addition to this, infective endocarditis and Aspergillosis, syphilis infection, trauma and cocaine use has also been indicated as a cause of mycotic aneurysms (Rinkel, Gijn and Wijdicks, 1993.Age has also been shown to be a predisposing factor. For instance abdominal aortic aneurysms are not very common below 6o years. However, it has been shown that 1 out of 1000 people develops this health condition between the age of 65 to 75 and this number is ever increasing (Rinkel et al, 1993). Types of aneurysms Most of aneurysms do occur in the aorta which is the main artery carrying oxygenated blood. Aneurysms occur in various parts of the body and they can be classified based on where they occur. For instance, if occurs in those arteries supplying the brain they are called cerebral / brain aneurysm. Brain aneurysms are also called berry aneurysms as they look like a small berry. Most of these brain aneurysms do not cause any symptom till they become large or start leaking blood .When they occur in the aorta, they are called Aortic aneurysms and they arise due to loss of smooth muscle cells and elastin in aortic walls (Reed et al, 1992).These aneurysms can occur in the ascending aorta (aortic arch) or the descending thoracic aorta. If it occurs in the chest part of aorta usually above diaghram, they are called thoracic aortic aneurysms, TAA or thoracic aneurysm. On the other hand, abdominal aneurysms are as a result of dilation of blood vessels supplying the abdomen, legs and pelvis. The risk factor for development are obesity, high cholesterol, genetic factors, emphysema, male gender especially above 60 years, smoking (“Aortic aneurysms”, 2012).Apart from aortic aneurysms, aortic dissection (also called dissecting aneurysms) do occur and they involve longitudinal separation of the intima wall from the adventitia. Dissecting aneurysm occur mainly in late stages of life and are mainly seen among men more than women (Dobrin, 1989).Ventricular aneurysms occurs in the left ventricle which is the main pumping chamber. It occurs if this section of the heart becomes damaged either through heart attack or through scarring thus becoming thinner and weaker. The weakened area of the heart makes it harder to pump blood to the rest of the body (“Aneurysms and dissection”, 2011). Peripheral aneurysms are a type of aneurysms which are found in other arteries other than aorta, in locations such as popliteal, femoral and coratid arteries. Popliteal arteries run down thighs back and behind the knees and account for 84% of all peripheral aneurysms while femoral arteries supply the groin region. Additionally, carotid arteries occur as pairs on each side of the neck (“ Iliac Artery Aneurysm or IAA”, 2012). Among the peripheral aneurysms, it is only iliac artery aneurysms which are mainly linked with abdominal aortic aneurysms. The iliac aneurysm is composed of 3 arteries which the common iliac artery, external iliac artery and internal iliac artery. The common iliac artery constitutes the terminus of aorta and runs inferolaterally along the media border of psoa muscles to the pelvic brim. The external iliac artery and internal artery supplies the sexual organs. Most of iliac aneurysms occurs in common iliac artery and this accounts for 70-90% while 10-30% occurs in internal iliac artery and external iliac is not involved (“ Iliac Artery Aneurysm or IAA”, 2012).The major cause of iliac aneurysm is arteriosclerosis although it can occur during pregnancy or following syphylic infection (“ Iliac Artery Aneurysm or IAA”, 2012). Pathophysiology The symptoms of aneurysms vary depending on the type and location of the aneurysm in the body. The symptoms are also due to the effects of pressure on the nearby organs, blood vessels or nerves. (“Aneurysms and dissections”, 2011).When an aneurysm occurs near the body surface then a swelling that has throbbing mass at the site of aneurysm can be seen. However, it may not show any symptom if it occurs within the body or in the brain until it bursts. For most of aortic aneurysms, they are asymptomatic. However, on enlarging symptoms such as backache, abdominal pain, pain between shoulders or on the left shoulder may occur. When nerve roots are compressed this can lead to numbness, or pain in the legs (“Aortic aneurysms”, 2012). Other symptoms which may develop are anxiety, stress, nausea, vomiting rapid heart rate, shortness in breath, presence of croaky voice and discomfort due to stretching vessel. In case of rupture it causes severe pain and internal bleeding and if not promptly treated, this may lead to sudden death (Reed et al, 1992; “Aortic aneurysms”, 2012). For thoracic aneurysms, most of them are asymptomatic and symptoms start appearing when the aneurysm starts bulging or leaking out. This enlargement or leakage is coupled with symptoms such as chest pain or back pain (“Aortic aneurysms”, 2012). (Healthbase). Abdominal aortic aneurysms may cause tenderness or pain below the stomach, cause stomach ups, groin pain, back pain and abdominal palpation can be seen (Reed et al, 1992).For those patients having aortic dissections, they may show symptoms such as sudden stomach pain and chest pain which may spread to the back and between the shoulders .If blood leaks out of the dissection, it builds up consequently entering the pericardial space which surrounds the heart. This prevents the heart from filling properly consequently causing a life threatening condition called cardiac tamponade (Reed et al, 1992). In case of cerebral aneurysms, they occur without symptoms but the patient may have headache, pain in the neck, and face, problem when seeing or taking. When seizures occur they are coupled with haemorrages, confusion, stiff neck, light sensitivity nausea and vomiting (Reed et al, 1992). For iliac aneurysms, most of them are asymptomatic until bursting occurs. Compression of adjacent pelvic structures can occur thus interfering with organ function. Other symptoms are abdominal pain, obstruction of urethra, hematuria, thrombosis of iliac vein, obstruction of large bowel and in some cases neurological deficit can occur (“Iliac Artery Aneurysm or IAA”, 2012). Complications of aneurysms Thoracic abdominal aneurysms are very serious as they involve body cavities, have difficulty in accessing them anatomically, affect major arteries of the abdominal viscera which are celiac, superior mesenteric and renal arteries. There is therefore potential danger of causing fatal ischemic damage to vital organs such as liver, kidneys, GIT, due to temporally arrest of circulation to these organs when incision and graft replacement is being done performed (Mastracci and Eagleton, 2011). Rupturing of intracranial aneurysms may cause a stroke called subarachnoid hemorrhage (SAH) with 50% of patients dying due to hemorrhage and 30% of those who survive becoming dependent for all activities of their life (Mastracci and Eagleton, 2011). Secondary outcomes such as epilepsy, re-bleeding after aneurysm treatment, sudden deaths due to death hemorrhage, respiratory complication, interference with sexual functions (especially men which is characterized by importance or failure of erection) and neuropsychological effects (Molyneux,, Kerr, Yu, Clarke, Sneade, Yarnold and Sandercock, 2005).Other complication are thromboembolism which involves blood clot formation thus preventing blood flow to the limbs. The aneurysms can also be infected with other pathogens. In the brain, bleeding can cause stroke, intracranial hematoma where blood clot forms in the skull (Laxdal, Amundsen, Dregelid, Pedersen and Aune, 2004). Other complications are aorta venous fistula which is an abnormal connection between the aorta and vein, aorta enteric fistula (abnormal connection between the bowel and aorta) and inflammation of aneurysms causing a condition called inflammatory aneurysms (Laxdal et al, 2004). Diagnosis of aneurysms Diagnosis of aneurysms is achieved through the use of basic chest, stomach X-ray and use of ultrasound scanners. Determining of aneurysm size and its location is done using echocardiography, radiological imaging techniques such as computerized tomography (CT), Scanning, arteriography and magnetic resonance imaging (MRI) (“Aneurysms and dissections”, 2011). Other test is DNA diagnostic test used for detecting the presence or absence of genes such as Type111 collagen and other arterial proteins. This helps to identify those who have inherited the mutations hence their risk of developing aneurysms (Kulvaniemi et al, 1991). For abdominal aneurysms, examination of the presence of abdominal palpation can also be useful. Treatment There are a number of factors which determine the type of treatment to be adopted .These factors are the size and growth rate of aneurysms , symptom development, presence of other aneurysm and surgical risk involved such as heart rate irregularities due to surgery, pneumonia , and the patient’s general health (“Aneurysms and dissections”, 2011). Surgical repair is required for type A aortic aneurysms which occur in the ascending aorta (upper chest).For type B aortic aneurysms which occurs in the descending thoracic and abdominal aorta , they are not life threatening but they should be monitored regularly until they become 5cm in diameter when they can be surgically removed and replaced with fabric substitutes to prevent bursting .Other options are endovascular stenting which is a less invasive technique (“Aneurysms and dissections”, 2011) .In peripheral aneurysms, surgery is done to replace the weakened part of blood vessel with a graft or artificial tube which keeps the artery open (“Aneurysms and dissections”, 2011). For those patients with stable type of aneurysms in the abdominal and descending part of aorta, regular checkups are recommended in order to monitor the aneurysm growth. If it doesn’t grow further the patient can stay with it for years. Doctors can also prescribe medicines such as Beta blockers which reduces blood pressure on the walls of aorta. These medicines are important for those patients who a have higher risk of aneurysm than the aneurysm itself (“Aneurysms and dissections”, 2011). For patients with aortic dissections, surgery is recommended right away especially for type A dissection which occur in aorta near the heart. Surgical repair involves opening of the ballooned part of blood vessel and sewing the proximal and distal portions of aorta and thus closing the aneurismal sac around the inserted artificial tube. For type B dissections which are far from the heart, the patients should be prescribed medicines such as Beta blockers to reduce blood pressure followed by regular checkups of the aneurysm growth until when it warrants surgery (“Aneurysms and dissections”, 2011). Non surgical procedures have also been used for treatment of AAAs .This technique is useful for treating those patients with a high surgical risk or who cannot have surgery due to their overall health conditions such as the presence of metastatic cancer which can increase operative risk (Dorros, 1997). This procedure involves insertion of a device called stent graft using a catheter and it is placed within the artery where the aneurysm occurs. Blood flows through the graft thus reducing the pressure on the damaged / weakened artery. The overall effect of stent graft is that, it prevents the aneuryms from bursting (Molyneux et al, 2005).Today the use of endovascular therapy in treating unruptured aneurysm is widely being used (Mastracci and Eagleton, 2011). Treatment of intracranial aneurysms using balloon assisted detachable coils has become an alternative to surgical clipping .Such coils are placed in the aneurismal lumen .It has been shown to be useful for treating aneurysms that have wide neck or those with low SNR (sac diameter/neck size ratio of 1.5 or less (Cottier et al, 2001).This technique is recommended when conventional treatment has failed and it offers a number of advantages. The balloon is important as it ensures that the coil does not protrude into the parent artery. It also stabilizes microcatheter at the aneurismal site during delivery of coil. The use of coil also ensure dense packaging in the neck level (Cottier et al, 2001) Economic costs of aneurysms The estimated lifetime cost for patients with unruptured intracranial aneurysms in USA is $522,500 while patients with aneurismal subarachnoid hemorrhage is $1755600 .These costs includes costs for hospitalization, mortality, morbidity and surgery (Weibers, Torner and Meissner, 1992).In UK quality life adjusted life (DALYS) to aneurismal subarachnoid hemorrhage (aSAH) has been estimated to be ?168.2 million in each year. This includes 59% of patient hospitalization, 18% community health and social services 15% of operations and 6% of cerebrovascular rehabilitation. Each patient it has been estimated to have a cost of ?213,294 and a total of 80,356 life year are lost due to aSAH. The economic burden of this disease has been estimated to be ?510 million in UK (Arias, Gray and Wolstenholme, 2010). Longevity of patients with aneurysms The life expectancy of patients who have undergone a successful aneurysm repair is almost same to those of normal population while the overall risk of death due to aneurismal is 50% (Arias et al, 2010). References Aneurysms and dissection. (2011). Retrieved March 12, 2012, from Texas heart Institute: Website, http://www.texasheartinstitute.org/hic/topics/cond/aneurysm.cfm Arias, O.R., Gray, A. and Wolstenholme, J. (2010). Burden of disease and costs oif aneurysmal subarachnoid haemorrhage (aSAH) in the United Kingdom. Cost and efectiveness and resource allocation , 8 (6). Doi:10.1186/1478-7547-8-6 Cottier, J.P., Posco, A., Gallas, S., Gabrillargues, J., Cognard, C.,Drouineuau, J.,Brunereau, L. and Herbreteau, D. (2001). Utility of Balloon-assisted Guglielmi Detachable Coilingin the Treatment of 49 Cerebral Aneurysms:A Retrospective, Multicenter Study. Am J neuroradiol , 22, 345-351. 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Retrieved March12, 2012, from: National heart lung and blood institute people science health Website, http://www.nhlbi.nih.gov/health/health-topics/topics/arm Read More