eMedicine Specialties > Vascular Surgery > Medical Topics
Abdominal Aortic Aneurysm: Treatment
Updated: Oct 28, 2009
Treatment
Medical Therapy
In patients with small abdominal aortic aneurysms (AAAs), attempt to reduce the expansion rate and rupture risk. Smoking cessation is of paramount importance. Aggressively control hypertension. Institute beta-blocker therapy to reduce blood pressure and stress on the artery wall. These can be administered safely unless the patient has contraindications to their use, such as COPD, allergy to the drug, bradycardia, or severe CHF.
Surgical Therapy
The decision to treat an abdominal aortic aneurysm (AAA) is based on operative risk, the risk of rupture, and the patient’s estimated life expectancy. In 2003, the Society for Vascular Surgery (SVS) published a series of guidelines for the treatment of AAAs based on these principles.6 The operative risk is based on patients’ comorbidities and hospital factors. Patient characteristics, including age, gender, renal function, and cardiopulmonary disease are perhaps the most important (see Table 1).
Table 1. Operative Mortality Risk of Open AAA Repair
Open table in new window
| AAA diameter (cm) | Rupture risk (%/y) |
| <4 | 0 |
| 4-5 | 0.5-5 |
| 5-6 | 3-15 |
| 6-7 | 10-20 |
| 7-8 | 20-40 |
| >8 | 30-50 |
Furthermore, lower volume hospitals and surgeons are associated with higher mortality.7 The risk of rupture is generally related to size (see Table 2), but other patient variables are important.
Table 2. Estimated Annual Rupture RiskOpen table in new window
[ CLOSE WINDOW ]Table
Low risk Average risk High risk Diameter <5 cm 5-6 cm >6 cm Expansion <0.3 cm/y 0.3-0.6 cm/y >0.6 cm/y Smoking/COPD None, mild Moderate Severe / steroids Family history No relatives One relative Numerous relatives Hypertension Normal blood pressure Controlled Poorly controlled Shape Fusiform Saccular Very eccentric Wall stress Low (35 N/cm2 Mdm. (40 N/cm2 High (45 N/cm2) Gender ... Male Female
Low risk Average risk High risk Diameter <5 cm 5-6 cm >6 cm Expansion <0.3 cm/y 0.3-0.6 cm/y >0.6 cm/y Smoking/COPD None, mild Moderate Severe / steroids Family history No relatives One relative Numerous relatives Hypertension Normal blood pressure Controlled Poorly controlled Shape Fusiform Saccular Very eccentric Wall stress Low (35 N/cm2 Mdm. (40 N/cm2 High (45 N/cm2) Gender ... Male Female
A higher risk of rupture is associated with gender, aneurysm expansion rate, family history, and COPD (see Table 3).
Table 3. Rupture RiskOpen table in new window
[ CLOSE WINDOW ]Table
Good risk Moderate risk High risk Age >70 y Age 70-80 y Age 80 y Physically active Active Inactive, poor stamina No clinically overt cardiac disease Stable coronary disease; remote MI;
EF >35%Significant coronary disease; recent MI;
frequent angina; CHF; EF <25%No significant comorbidities Mild COPD Limiting COPD; dyspnea at rest; O2
dependency; FEV1 >1 I./sec... Creatinine 2.0-3.0 ... Normal anatomy Adverse anatomy or AAA
characteristicsCreatinine >3 No adverse AAA characteristics ... Liver disease (h PT; albumin <2) Anticipated operative mortality, 1%-3% Anticipated operative mortality, 3%-7% Anticipated operative mortality, at least
5%-10%; each comorbid condition
adding approximately 3%-5%
mortality risk
Good risk Moderate risk High risk Age >70 y Age 70-80 y Age 80 y Physically active Active Inactive, poor stamina No clinically overt cardiac disease Stable coronary disease; remote MI;
EF >35%Significant coronary disease; recent MI;
frequent angina; CHF; EF <25%No significant comorbidities Mild COPD Limiting COPD; dyspnea at rest; O2
dependency; FEV1 >1 I./sec... Creatinine 2.0-3.0 ... Normal anatomy Adverse anatomy or AAA
characteristicsCreatinine >3 No adverse AAA characteristics ... Liver disease (h PT; albumin <2) Anticipated operative mortality, 1%-3% Anticipated operative mortality, 3%-7% Anticipated operative mortality, at least
5%-10%; each comorbid condition
adding approximately 3%-5%
mortality risk
Research also suggests that the aneurysm’s morphology may increase the risk of rupture.8 Prospective studies have concluded that following aneurysms larger than 5.5 cm with serial ultrasounds or CT scans is safe. A slightly higher rupture rate in women exists, and this threshold may be lower. Thus, the decision to repair an AAA is a complex one in which the patient must play an important role. In some very elderly patients or patients with limited life expectancy, aneurysm repair may not be appropriate. In these patients, the consequences of rupture should be frankly discussed. If rupture occurs, no intervention should be performed.
Abdominal aortic aneurysms are typically repaired by an operative intervention. The procedure can be approached through the traditional open laparotomy approach or, now, by newer minimally invasive methodologies or by the placement of endovascular stents.
Preoperative Details
Preoperatively, obtain a careful history and perform a physical examination and laboratory assessment. From the information derived from these basic assessments, perioperative risk and life expectancy after the proposed procedure can be estimated.
Carefully consider whether the patient's current quality of life is sufficient to justify the operative intervention. Because the disease process affects elderly persons who may be debilitated or may have mental deterioration, this decision is made in conjunction with the patient and family.
Once the decision is made, identify comorbidities and risk factors that increase the operative risk or decrease survival. Ascertain the patient's activity level, stamina, and stability of health. Perform a thorough cardiac assessment tailored in accordance with the patient's history, symptomatology, and results from preliminary screening tests such as the electrocardiogram and stress test.
Because COPD is an independent predictor of operative mortality, assess lung function by performing a room-air arterial blood gas measurement and pulmonary function tests. In patients with abnormal test results, preoperative intervention in the form of bronchodilators and pulmonary toilet often can reduce operative risks and postoperative complications.
Preoperative intravenous antibiotics (usually a cephalosporin) are administered to reduce the risk of infection. Arranging for appropriate intravenous accesses to accommodate blood loss, arterial pressure monitoring through an arterial line, and Foley catheter placement to monitor urine output are routine preparations for surgery. For patients at high risk because of cardiac compromise, a Swan-Ganz catheter is placed to assist with cardiac monitoring and volume assessment. Transesophageal echocardiography can be useful to monitor ventricular volume and cardiac wall motion and to provide a guide with respect to fluid replacement and pressor use.
Prepare for blood replacement. The patient should have blood available for transfusion. Intraoperative Cell Saver use and preoperative autologous blood donation have become popular.
Maintain a normal body temperature during the operative intervention to prevent coagulopathy and maintain normal metabolic function. To prevent hypothermia, place a recirculating, warm forced-air blanket on the patient and warm any intravenous fluids and blood before administration.
The following are standard preoperatively:
- Type and crossmatch blood.
- Administer prophylactic antibiotics (cefazolin, 1 g intravenous piggyback).
- Insert a Foley catheter.
- Establish large-bore intravenous access.
- Monitor central venous pressure or establish Swan-Ganz catheterization (if indicated).
- Prepare the skin from the nipples to the mid thigh.
- Administer general anesthesia (with or without epidural anesthesia).
- Cell Saver use has become popular.
- Insert a nasogastric tube.
Intraoperative Details
Approach
The aorta may be approached either transabdominally or through the retroperitoneal space. Approach juxtarenal and suprarenal aortic aneurysms from the left retroperitoneal space.
Self-retaining retractors are used. Keep the bowel warm and, if possible, not exteriorized. The abdomen is explored for abnormalities (eg, gallstones, associated intestinal or pancreatic malignancy).
Depending on the patient's anatomy, the aorta can be reconstructed with a tube graft, an aortic iliac bifurcation graft, or an aortofemoral bypass.
For proximal infrarenal control, first identify the left renal vein. Occasionally, patients may have a retroaortic vein (<5%). In this situation, take care when placing the proximal clamp. Division of the left renal vein is usually required to clamp above the renal arteries.
Regarding pelvic outflow, in most instances, the inferior mesenteric artery is sacrificed. Therefore, to prevent colon ischemia, make every attempt to restore at least one hypogastric (internal iliac) artery perfusion. If the hypogastric arteries are sacrificed (associated aneurysms), reimplant the inferior mesenteric artery.
For supraceliac aortic control, first divide the ligaments to the left lateral segment of the liver and then retract the segment. The crura of the diaphragm are separated, and the aorta is bluntly dissected. Supraceliac control is recommended for inflammatory aneurysms.
The aorta is reconstructed from within using PTFE or Dacron. The aneurysm sac is closed, and the graft is put into the duodenum to prevent erosion.
Special considerations
Inflammatory aneurysms require supraceliac control, minimal dissection of the duodenum, and balloon occlusion of the iliac arteries.
In patients with inflammatory aneurysms or large iliac artery aneurysms, identify the ureters; occasionally, ureteral stents are recommended in patients with inflammatory aneurysms.
Prevention of distal embolization
The patient is heparinized (5000 U intravenously) prior to aortic cross-clamping. If significant intraluminal debris, juxtarenal thrombus, or prior peripheral embolization is present, the distal arteries are clamped first, followed by aortic clamping.
Before restoring lower extremity blood flow, both forward flow (aortic) and back flow (iliac) are allowed to remove debris. The graft is also irrigated to flush out debris.
The colon is inspected prior to closure, and the femoral arteries are palpated. Before the patient leaves the operating room, determine lower extremity circulation. If a clot was dislodged at the time of aortic clamping, it can be removed with a Fogarty embolectomy catheter. Heparin reversal is not usually required.
Postoperative Details
Fluid shifts are common following aortic surgery. Fluid requirements may be high in the first 12 hours, depending on the amount of blood loss and fluid resuscitation in the operating room. Monitor the patient in the surgical intensive care unit for hemodynamic stability, bleeding, urine output, and peripheral pulses. A postoperative electrocardiogram and chest radiograph are needed. Prophylactic antibiotics (eg, cefazolin at 1 g) are administered for 24 hours.
Follow-up
The patient is seen in 1-2 weeks for suture or skin staple removal, then yearly thereafter.
For excellent patient education resources, visit eMedicine's Circulatory Problems Center and Cholesterol Center. Also, see eMedicine's patient education articles Aortic Aneurysm, High Cholesterol, and Cholesterol FAQs.
Complications
- Death - 1.8-5% if elective and 50% if ruptured
- Pneumonia - 5%
- Myocardial infarction - 2-5%
- Groin infection - Less than 5%
- Graft infection - Less than 1%
- Colon ischemia - Less than 1% if elective and 15-20% if ruptured
- Renal failure related to preoperative creatinine level, intraoperative cholesterol embolization, and hypotension
- Incisional hernia - 10-20%
- Bowel obstruction
- Amputation from major arterial occlusion
- Blue toe syndrome and cholesterol embolization to feet
- Impotence in males - Erectile dysfunction and retrograde ejaculation (>30%)
- Paresthesias in thighs from femoral exposure (rare)
- Lymphocele in groin - Approximately 2%
- Late graft enteric fistula
More on Abdominal Aortic Aneurysm |
| Overview: Abdominal Aortic Aneurysm |
| Workup: Abdominal Aortic Aneurysm |
 Treatment: Abdominal Aortic Aneurysm |
| Follow-up: Abdominal Aortic Aneurysm |
| Multimedia: Abdominal Aortic Aneurysm |
| References |
| « Previous Page | Next Page » |
References
Parodi JC, Palmaz JC, Barone HD. Transfemoral intraluminal graft implantation for abdominal aortic aneurysms. Ann Vasc Surg. Nov 1991;5(6):491-9. [Medline].
Lederle FA, Johnson GR, Wilson SE, Chute EP, Littooy FN, Bandyk D. Prevalence and associations of abdominal aortic aneurysm detected through screening. Aneurysm Detection and Management (ADAM) Veterans Affairs Cooperative Study Group. Ann Intern Med. Mar 15 1997;126(6):441-9. [Medline].
Majumder PP, St Jean PL, Ferrell RE, Webster MW, Steed DL. On the inheritance of abdominal aortic aneurysm. Am J Hum Genet. Jan 1991;48(1):164-70. [Medline].
Tilson MD, Ozsvath KJ, Hirose H, Xia S. A genetic basis for autoimmune manifestations in the abdominal aortic aneurysm resides in the MHC class II locus DR-beta-1. Ann N Y Acad Sci. Nov 18 1996;800:208-15. [Medline].
Wassef M, Baxter BT, Chisholm RL, Dalman RL, Fillinger MF, Heinecke J. Pathogenesis of abdominal aortic aneurysms: a multidisciplinary research program supported by the National Heart, Lung, and Blood Institute. J Vasc Surg. Oct 2001;34(4):730-8. [Medline].
Brewster DC, Cronenwett JL, Hallett JW Jr, Johnston KW, Krupski WC, Matsumura JS. Guidelines for the treatment of abdominal aortic aneurysms. Report of a subcommittee of the Joint Council of the American Association for Vascular Surgery and Society for Vascular Surgery. J Vasc Surg. May 2003;37(5):1106-17. [Medline].
The UK Small Aneurysm Trial Participants. Mortality results for randomized controlled trial of early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. Lancet. 1998;353:1649-55.
Lederle FA, Wilson SE, Johnson GR, Reinke DB, Littooy FN, Acher CW. Immediate repair compared with surveillance of small abdominal aortic aneurysms. N Engl J Med. May 9 2002;346(19):1437-44. [Medline].
Tan JW, Yeo KK, Laird JR. Food and Drug Administration-approved endovascular repair devices for abdominal aortic aneurysms: a review. J Vasc Interv Radiol. Jun 2008;19(6 Suppl):S9-S17. [Medline].
Ailawadi G, Eliason JL, Upchurch GR Jr. Current concepts in the pathogenesis of abdominal aortic aneurysm. J Vasc Surg. Sep 2003;38(3):584-8. [Medline].
Baron JF, Mundler O, Bertrand M, Vicaut E, Barré E, Godet G. Dipyridamole-thallium scintigraphy and gated radionuclide angiography to assess cardiac risk before abdominal aortic surgery. N Engl J Med. Mar 10 1994;330(10):663-9. [Medline].
Bender JS, Smith-Meek MA, Jones CE. Routine pulmonary artery catheterization does not reduce morbidity and mortality of elective vascular surgery: results of a prospective, randomized trial. Ann Surg. Sep 1997;226(3):229-36; discussion 236-7. [Medline].
Bickerstaff LK, Hollier LH, Van Peenen HJ, Melton LJ 3rd, Pairolero PC, Cherry KJ. Abdominal aortic aneurysms: the changing natural history. J Vasc Surg. Jan 1984;1(1):6-12. [Medline].
Brady AR, Fowkes FG, Greenhalgh RM, Powell JT, Ruckley CV, Thompson SG. Risk factors for postoperative death following elective surgical repair of abdominal aortic aneurysm: results from the UK Small Aneurysm Trial. On behalf of the UK Small Aneurysm Trial participants. Br J Surg. Jun 2000;87(6):742-9. [Medline].
Breckwoldt WL, Mackey WC, O'Donnell TF Jr. The economic implications of high-risk abdominal aortic aneurysms. J Vasc Surg. Jun 1991;13(6):798-803; discussion 803-4. [Medline].
Brown PM, Pattenden R, Gutelius JR. The selective management of small abdominal aortic aneurysms: the Kingston study. J Vasc Surg. Jan 1992;15(1):21-5; discussion 25-7. [Medline].
Brown PM, Pattenden R, Vernooy C, Zelt DT, Gutelius JR. Selective management of abdominal aortic aneurysms in a prospective measurement program. J Vasc Surg. Feb 1996;23(2):213-20; discussion 221-2. [Medline].
Bunt TJ. Synthetic vascular graft infections. I. Graft infections. Surgery. Jun 1983;93(6):733-46. [Medline].
Bunt TJ. Synthetic vascular graft infections. II. Graft-enteric erosions and graft-enteric fistulas. Surgery. Jul 1983;94(1):1-9. [Medline].
Chang JB, Stein TA, Liu JP, Dunn ME. Risk factors associated with rapid growth of small abdominal aortic aneurysms. Surgery. Feb 1997;121(2):117-22. [Medline].
Crawford ES, Cohen ES. Aortic aneurysm: a multifocal disease. Presidential address. Arch Surg. Nov 1982;117(11):1393-400. [Medline].
Crawford ES, Saleh SA, Babb JW 3rd, Glaeser DH, Vaccaro PS, Silvers A. Infrarenal abdominal aortic aneurysm: factors influencing survival after operation performed over a 25-year period. Ann Surg. Jun 1981;193(6):699-709. [Medline].
Cronenwett JL, Sargent SK, Wall MH, Hawkes ML, Freeman DH, Dain BJ. Variables that affect the expansion rate and outcome of small abdominal aortic aneurysms. J Vasc Surg. Feb 1990;11(2):260-8; discussion 268-9. [Medline].
Davies MJ. Aortic aneurysm formation: lessons from human studies and experimental models. Circulation. Jul 21 1998;98(3):193-5. [Medline].
Ernst CB. Abdominal aortic aneurysm. N Engl J Med. Apr 22 1993;328(16):1167-72. [Medline].
Frame PS, Fryback DG, Patterson C. Screening for abdominal aortic aneurysm in men ages 60 to 80 years. A cost-effectiveness analysis. Ann Intern Med. Sep 1 1993;119(5):411-6. [Medline].
Gadowski GR, Pilcher DB, Ricci MA. Abdominal aortic aneurysm expansion rate: effect of size and beta- adrenergic blockade. J Vasc Surg. Apr 1994;19(4):727-31. [Medline].
Gillum RF. Epidemiology of aortic aneurysm in the United States. J Clin Epidemiol. Nov 1995;48(11):1289-98. [Medline].
Gomes MN, Choyke PL, Wallace RB. Infected aortic aneurysms. A changing entity. Ann Surg. May 1992;215(5):435-42. [Medline].
Grange JJ, Davis V, Baxter BT. Pathogenesis of abdominal aortic aneurysm: an update and look toward the future. Cardiovasc Surg. Jun 1997;5(3):256-65. [Medline].
Greenhalgh RM, Forbes JF, Fowkes FG, Powel JT, Ruckley CV, Brady AR. Early elective open surgical repair of small abdominal aortic aneurysms is not recommended: results of the UK Small Aneurysm Trial. Steering Committee. Eur J Vasc Endovasc Surg. Dec 1998;16(6):462-4. [Medline].
Gregory AK, Yin NX, Capella J, Xia S, Newman KM, Tilson MD. Features of autoimmunity in the abdominal aortic aneurysm. Arch Surg. Jan 1996;131(1):85-8. [Medline].
Guirguis EM, Barber GG. The natural history of abdominal aortic aneurysms. Am J Surg. Nov 1991;162(5):481-3. [Medline].
Hallett JW Jr, Marshall DM, Petterson TM, Gray DT, Bower TC, Cherry KJ Jr. Graft-related complications after abdominal aortic aneurysm repair: reassurance from a 36-year population-based experience. J Vasc Surg. Feb 1997;25(2):277-84; discussion 285-6. [Medline].
Johnston KW, Hertzer NR, Rutherford RB, et al. Joint Council guidelines for disclosure of conflict of interest. J Vasc Surg. Jul 2000;32(1):213-5. [Medline].
Laheij RJ, Buth J, Harris PL, Moll FL, Stelter WJ, Verhoeven EL. Need for secondary interventions after endovascular repair of abdominal aortic aneurysms. Intermediate-term follow-up results of a European collaborative registry (EUROSTAR). Br J Surg. Dec 2000;87(12):1666-73. [Medline].
Lederle FA, Johnson GR, Wilson SE, Chute EP, Hye RJ, Makaroun MS. The aneurysm detection and management study screening program: validation cohort and final results. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators. Arch Intern Med. May 22 2000;160(10):1425-30. [Medline].
May J, White GH, Yu W, Waugh R, Stephen MS, Chaufour X. Endovascular grafting for abdominal aortic aneurysms: changing incidence and indication for conversion to open operation. Cardiovasc Surg. Apr 1998;6(2):194-7. [Medline].
Moore WS, Brewster DC, Bernhard VM. Aorto-uni-iliac endograft for complex aortoiliac aneurysms compared with tube/bifurcation endografts: results of the EVT/Guidant trials. J Vasc Surg. Feb 2001;33(2 Suppl):S11-20. [Medline].
Ouriel K, Geary K, Green RM, Fiore W, Geary JE, DeWeese JA. Factors determining survival after ruptured aortic aneurysm: the hospital, the surgeon, and the patient. J Vasc Surg. Apr 1990;11(4):493-6. [Medline].
Ouriel K, Green RM, Donayre C, Shortell CK, Elliott J, DeWeese JA. An evaluation of new methods of expressing aortic aneurysm size: relationship to rupture. J Vasc Surg. Jan 1992;15(1):12-8; discussion 19-20. [Medline].
Raghavan ML, Vorp DA, Federle MP, Makaroun MS, Webster MW. Wall stress distribution on three-dimensionally reconstructed models of human abdominal aortic aneurysm. J Vasc Surg. Apr 2000;31(4):760-9. [Medline].
Rasmussen TE, Hallett JW Jr. Inflammatory aortic aneurysms. A clinical review with new perspectives in pathogenesis. Ann Surg. Feb 1997;225(2):155-64. [Medline].
Rutherford RB, Krupski WC. Current status of open versus endovascular stent-graft repair of abdominal aortic aneurysm. J Vasc Surg. May 2004;39(5):1129-39. [Medline].
Stella A, Gargiulo M, Faggioli GL, Bertoni F, Cappello I, Brusori S. Postoperative course of inflammatory abdominal aortic aneurysms. Ann Vasc Surg. May 1993;7(3):229-38. [Medline].
Tung WS, Lee JK, Thompson RW. Simultaneous analysis of 1176 gene products in normal human aorta and abdominal aortic aneurysms using a membrane-based complementary DNA expression array. J Vasc Surg. Jul 2001;34(1):143-50. [Medline].
Vohra R, Reid D, Groome J, Abdool-Carrim AT, Pollock JG. Long-term survival in patients undergoing resection of abdominal aortic aneurysm. Ann Vasc Surg. Sep 1990;4(5):460-5. [Medline].
Vorp DA, Raghavan ML, Webster MW. Mechanical wall stress in abdominal aortic aneurysm: influence of diameter and asymmetry. J Vasc Surg. Apr 1998;27(4):632-9. [Medline].
White GH, May J, McGahan T, Yu W, Waugh RC, Stephen MS. Historic control comparison of outcome for matched groups of patients undergoing endoluminal versus open repair of abdominal aortic aneurysms. J Vasc Surg. Feb 1996;23(2):201-11; discussion 211-2. [Medline].
Wills A, Thompson MM, Crowther M, Sayers RD, Bell PR. Pathogenesis of abdominal aortic aneurysms--cellular and biochemical mechanisms. Eur J Vasc Endovasc Surg. Nov 1996;12(4):391-400. [Medline].
Zarins CK, Wolf YG, Lee WA, Hill BB, Olcott C IV, Harris EJ. Will endovascular repair replace open surgery for abdominal aortic aneurysm repair?. Ann Surg. Oct 2000;232(4):501-7. [Medline].
Further Reading
Keywords
abdominal aortic aneurysm, abdominal aortic aneurysms, aortic ectasia, arteriomegaly, diffuse arterial enlargement, atherosclerotic vascular disease, Marfan's syndrome, Marfan syndrome, AAA, aortic rupture, atherosclerosis, Dacron, Gore-Tex
