Abdominal aortic aneurysm repair: Matching patients with approaches

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                                The Surgical Patient

         Abdominal aortic aneurysm repair:
         Matching patients with approaches
      James F. Ginter, MPAS, PA-C; Jessica Linzmeyer

                     bdominal aortic aneurysm (AAA) is a common



      A              condition that primarily affects older patients
                     and can have fatal consequences. Rupture of
                     an AAA has an overall mortality rate of 80%;
                     in patients who reach the hospital alive, the
      mortality is close to 50%.1
        AAA is present in approximately 2% of the population and
      responsible for more than 13,750 deaths annually. Moreover,
                                                                                          renal artery




      AAA is an underlying or contributing cause of death in more
      than 19,000 patients and a factor in more than 63,000 hospi-
      tal discharges per year in the United States.2 The prevalence
      of AAA increases by 6% per decade after 65 years of age.3
      The abdominal aorta is the most common site of an arterial
      aneurysm. Most AAAs are asymptomatic and found inciden-
      tally on imaging for other complaints. Management of AAAs
      requires an understanding of the natural process of the dis-
      ease, history, and treatment options.                                                                     abdominal aorta

      DISCUSSION
      Definition An aneurysm is a focal dilation of a blood vessel as
      compared to the original or adjacent artery. An AAA is de-
      fined as an aortic diameter that is at least 1.5 times the diame-
      ter of the aorta at the renal arteries. In adults, the average                                                                    © Molly Borman
      diameter of the infrarenal abdominal aorta is approximately
      2.0 cm (range 1.66-2.39 cm).4 An infrarenal aorta with a
      diameter greater than 3.0 cm is considered to be aneurysmal
      (see Figure 1). Aneurysms can be classified as fusiform (exhib-
      iting circumferential expansion) or saccular (demonstrating         FIGURE 1. An infrarenal abdominal aorta measuring more than
      outpouching of a segment). (CT scans of a normal aorta and          3 cm in diameter is considered aneurysmal.
      an aneurysmal aorta are shown in Figures 2 and 3, page 28.)
         Etiology The mechanism for the development of AAA is               Risk factors The main risk factors for AAA are smoking,
      not fully understood. Several studies have assessed aortic his-     increasing age, male gender, and a family history of aneu-
      tology, protein abundance, and gene expressions. These stud-        rysms. A study by Wilmink and colleagues found that
      ies have found a loss of extracellular matrix with an accumu-       smokers are seven times more likely to have an AAA and
      lation of proteolytic enzymes and cytokines that weaken the         ex-smokers are three times more likely than age-matched
      aortic wall through breakdown of smooth muscle cells and            controls to have an AAA.7 More than 90% of patients with
      structural proteins.5,6 Smoking invokes an intra-aortic inflam-     an AAA have been smokers.3 The longer a patient has
      matory response that affects the immune-mediated pathways,          smoked, the higher the risk of AAA.7 The risk of an AAA
      leading to expansion of the aorta.6                                 steadily increases with age; AAAs are rarely found in per-



      26 JAAPA • JULY 2009 • 22(7) • www.jaapa.com
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                                               The Surgical Patient




      FIGURE 2. CT scan of a normal aorta                               FIGURE 3. CT scan of an aneurysmal aorta

      sons younger than 60 years. Men are four to five times            independent risk factors for rupture of an AAA: chronic
      more likely to have an AAA than women.8 A family history          obstructive pulmonary disease, hypertension, female gender,
      of AAA has been reported in up to 5% of AAA patients.9            smoking, and symptoms of abdominal pain or back pain.
      AAAs are more common in patients who have atherosclero-           Nonindependent risk factors for rupture are first-degree rela-
      sis; these patients are also at increased risk of other cardio-   tive with an AAA, sa
				
DOCUMENT INFO
Description: Rupture of an AAA has an overall mortality rate of 80%; in patients who reach the hospital alive, the mortality is close to 50%.1 AAA is present in approximately 2% of the population and responsible for more than 13,750 deaths annually. [...] AAA is an underlying or contributing cause of death in more than 19,000 patients and a factor in more than 63,000 hospital discharges per year in the United States.2 The prevalence of AAA increases by 6% per decade after 65 years of age.3 The abdominal aorta is the most common site of an arterial aneurysm.
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