What is the Abdominal Aortic Aneurysm?

 Abdominal aortic aneurysm (AAA) occurs when atherosclerosis or plaque buildup causes the walls of the abdominal aorta to become weak and bulge outward like a balloon. An AAA develops slowly over time and has few noticeable symptoms. The larger an aneurysm grows, the more likely it will burst or rupture, causing intense abdominal or back pain, dizziness, nausea or shortness of breath. Most people with an abdominal aortic aneurysm do not have any symptoms. Often, the aneurysm grow slowly and go unnoticed. Many never reach the point of bursting; others enlarge quickly. When an abdominal aneurysm expands, the patient may notice a throbbing in the middle or lower part of the stomach, lower back pain, or tenderness in the chest. Most abdominal aneurysms are identified during routine medical exams.

The aorta, the largest artery in the body, is a blood vessel that carries oxygenated blood away from the heart. It originates just after the aortic valve connected to the left side of the heart and extends through the entire chest and abdomen. The portion of the aorta that lies deep inside the abdomen, right in front of the spine, is called the abdominal aorta.

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Over time, artery walls may become weak and widen. An analogy would be what can happen to an aging garden hose. The pressure of blood pumping through the aorta may then cause this weak area to bulge outward, like a balloon (called an aneurysm). An abdominal aortic aneurysm (AAA, or "triple A") occurs when this type of vessel weakening happens in the portion of the aorta that runs through the abdomen.

The majority of AAAs are the result of atherosclerosis, a chronic degenerative disease of the artery wall, in which fat, cholesterol, and other substances build up in the walls of arteries and form soft or hard deposits called plaques. Large aneurysms are rare, but can be very serious. If a large aneurysm bursts, it causes huge internal bleeding and is usually fatal.

Abdominal aortic aneurysms typically develop slowly over a period of many years and hardly ever cause any noticeable symptoms. Occasionally, especially in thin patients, a pulsating sensation in the abdomen may be felt. The larger an aneurysm grows, the greater the chance it will burst, or rupture.

Major risk factors for an AAA include family history, smoking and longstanding high blood pressure. According to the Centers for Disease Control and Prevention (CDC), men who have a history of smoking should receive a one-time screening for triple A between the ages of 65 and 75. Men with a family history of AAA should be screened at age 60.

Abdominal aortic aneurysm (AAA) is a life-threatening condition which requires monitoring or treatment depending upon the size of the aneurysm and/or symptomatology. AAA may be detected prevalently or at the time of rupture. An arterial aneurysm is defined as a permanent localized dilatation of the vessel at least 150% compared to a relative standard adjacent diameter of that artery.

Treatment depends on a variety of factors, including size and location of the aneurysm within the abdominal aorta and the patient's age, kidney function and other conditions. Patients with aneurysms that are smaller than five centimeters in diameter are typically monitored with ultrasound or CT scans every six to 12 months and may be advised to:

·         quit smoking

·         control high blood pressure

·         lower cholesterol

There are two treatment options:

Traditional (open) surgical repair: In this type of surgery, an incision is made in the abdomen and the damaged part of the aorta is removed and replaced with a synthetic tube called a stent graft, which is sewn into place.

Endovascular surgery: In this procedure, which is less invasive than an open repair, the stent graft is attached to the end of a thin plastic tube called a catheter, inserted through an artery in the leg and maneuvered up into the abdomen, where it is positioned inside the aneurysm and fastened in place with small hooks.

Medical Management:

The medical therapies available to slow the growth of thoracic aortic aneurysms and reduce their risk of dissection or rupture are quite limited. Once β-blocker therapy is maximized (or in the event that β-blockers are contraindicated or not tolerated), any persistent hypertension should be treated with other antihypertensive agents to bring the blood pressure down to a low-normal range, e.g., a systolic pressure of 105 to 120 mm Hg. The 2005 ACC/AHA guidelines (1) recommended beta-blocker therapy in patients with an AAA who do not undergo surgery. Because of the possible attenuation of aneurysm expansion, beta-blockers are also a preferred drug for patients with hypertension or angina with care taken in patients with atrioventricular blocks, bradycardia, chronic obstructive pulmonary disease and peripheral vascular disease.

Antibiotic therapy: Interest in antibiotic therapy in the management of AAA is based on evidence of chronic inflammation in AAA, inhibition of proteases and inflammation by antibiotics, and possible involvement of Chlamydia pneumoniae in the pathogenesis of AAA.

Although cardiovascular disease is widely recognized as the leading cause of death, a lesser-known fact is that aortic aneurysm (AA) is the 15th leading cause of death over the age of 65 years in the US. The golden standard of the treatments in Abdominal Aortic Aneurysm are invasive interventions either with open surgical repair (OS) or endovascular aneurysm repair (EVAR). The concept of medical treatment is to prevent abdominal aortic aneurysm (AAA) from rupture and avoid surgical treatment by preventing aneurysm enlargement or even reducing aneurysm size. Matrix metalloproteinases (MMP) are structurally related metalloendopeptidases that can degrade the extracellular matrix, and is thought to play important roles in AAA. There are many proposed pharmacological treatments, including β-blockers, angiotensin-converting enzyme inhibitor (ACE inhibitors), angiotensin-receptor blocker (ARB), statins, macrolides and, doxycycline, an inhibitor of the MMP. Specific treatment is based on the age, overall health, medical history, extent of the disease, signs and symptoms, tolerance of specific medications, procedures, or therapies.

Unfortunately, no pharmacotherapy for AAA has been realized despite considerable effort, and there are several challenges that need to be addressed. First, it is possible that appropriate drug targets in human AAA have not been identified. Indeed, many animal studies have assessed the effects of interventions in limiting AAA development rather than the effects on pre-established AAA. Also, the experimental opportunities for analyzing human AAA specimens have decreased in recent years. Continued efforts, including the appropriate use and interpretation of animal models, and full utilization of human samples are essential to gain a better understanding of human AAA pathophysiology and pathogenesis. Second, it is important for pharmacotherapy to be sufficiently concentrated at the AAA site. Third, there is a possibility that the heterogeneity of human AAA might not be fully appreciated or taken into account when testing therapeutic agents since patients with AAA are heterogeneous in terms of their characteristics, clinical history, and genetic background.

The other factors that shall further expedite the growth of Abdominal Aortic Aneurysm market include increasing awareness about available treatments during the forecast period (2019–2030). Overall, the increasing prevalence, disease awareness, and promising emerging pipeline therapies will propel the market size forward during the forecast period. A better understanding of disease pathogenesis will also contribute to the development of novel therapeutics for Abdominal Aortic Aneurysm.

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