Open Journal Systems

DIAGNOSTIC AIDS

Received: October 22^nd 2014

Accepted: March 6^th 2015

Early detection of abdominal aortic aneurysm in risk population

María Elizabeth Enríquez-Vega,^a Hugo Francisco Solorio-Rosete,^b Alfonso Cossío-Zazueta,^c Héctor Bizueto-Rosas,^d Juan Ernesto Cruz-Castillo,^d Alessandra Iturburu-Enríquez^e

^aServicio de Angiología y Cirugía Vascular. Facultad de Medicina, División de Estudios de Posgrado Universidad Nacional Autónoma de México

^bAngiólogo y Cirujano Vascular, Querétaro, Querétaro, México

^cServicio de Cirugía

^dServcio de Angiología y Cirugía Vascular

^eMédico General

^c,dCentro Médico Nacional La Raza, Instituto Mexicano del Seguro Social, Distrito Federal

Communication with: María Elizabeth Enríquez-Vega

Teléfono celular: 5554313286, fax: 57547724

Email: elisa_angio@yahoo.com

Background: An aneurysm is the increase in diameter of an artery > 50 %; the abdominal aortic aneurysm (AAA) is the most frequent. Abdominal ultrasound is an accessible study, highly recommended for diagnosis. Screening at risk populations reduces morbidity and mortality of this disease.

Methods: To determine the frequency of AAA by duplex Doppler in patients older than 65 years old with risk factors. A cross sectional study was performed, from June to October 2012, 144 patients were included, both genders, > 65 years. The diameter of the infrarenal abdominal aorta was measured by duplex Doppler. AAA was defined as an aorta with diameter > 3 cm.

Results: Mean age was 72.7 ± 6.7, 95.1 % were male, 13 % continued smoking. 127 of 144 were normal. 10 of 144 had AAA with diameters of 3.2 to 7.11 cm, all of them male. Logistic regression showed that active smoking is a significant predictive factor for AAA.

Conclusion: There is a significant frequency of AAA in male patients > 65 years old.

Keywords: Abdominal aortic aneurysm, Ultrasound Doppler duplex, Detection.

---

An aneurysm is the increase in diameter of an artery > 50 % relative to an initial diameter. Infrarenal abdominal aortic aneurysms (AAA) are the most common, accounting for about 75% of all aneurysms.¹ An operational definition of practical interest indicates that a transverse diameter greater than 3 cm should be listed as AAA.^2,3

70 to 75% of AAA are asymptomatic, a large proportion of them are discovered as imaging findings in the study of other pathologies. In our country there are no early detection programs. When the diagnosis is made the aneurysm is already very large and this increases morbidity and mortality.^4,5 The most feared complication of AAA is rupture, whose calculated postoperative mortality is 47%; however, 66% of patients presenting with a ruptured aneurysm die before reaching the hospital or before entering surgery, so that overall mortality is in the range of 77 to 90%,6,7 while 30-day mortality for elective surgery is 5 to 8%.^5,7,8

The diagnosis by physical examination has a sensitivity of 39% and this improves as the size of the aneurysm increases, to 76% for AAA greater than or equal to 5 cm in diameter. Abdominal ultrasound is an accessible and useful test for the detection of AAA with a sensitivity of 87.4% and a specificity of 99.9%.⁶ Computerized axial tomography (CAT) is the gold standard for diagnosis as well as for the surgical plan with a sensitivity and specificity that exceed 95%.^7,9

There are numerous references in the literature about screening for AAA in patients at risk, the 4 most important randomized controlled studies being: Multicentre Aneurysm Study (MASS),¹⁰ Chichester,¹¹ Viborg,¹² and Western Australia.^13,14

There is enough scientific evidence to justify conducting AAA screening in male patients over 65 years.^9,15-17 The American Society for Vascular Surgery recommends secondary detection for AAA in male patients over 65 years with or without a history of smoking and female patients 65 and older with a history of smoking, and performing Doppler ultrasound monitoring at three years for aortas that have a diameter greater than 2.6 cm.¹⁸ Unfortunately in Latin America there are few studies of AAA screening, and in Mexico there are none.

Methods

A longitudinal, descriptive, prospective study was performed in the period between June and October 2012 with the main objective to estimate the frequency of AAA using duplex Doppler ultrasound in patients of both sexes over 65 years.

The following were taken as criteria: men 65 years or older with or without a history of smoking, and women with a history of smoking 65 years or older. A questionnaire was applied to obtain the following information: sex, age, smoking history, hypertension, diabetes mellitus (DM), and dyslipidemia. Duplex Doppler scanning was performed at the patient’s bedside, the infrarenal abdominal aorta was identified, and by a cross-section the maximum anterior-posterior diameter was identified. Diameter greater than or equal to 30 mm was used as a diagnostic criterion for AAA.

All information was captured and analyzed in SPSS version 11. Measures of central tendency (mode, mean, median, standard deviation) were analyzed. Logistic regression analysis was used for diagnostic predictors for AAA.

Results

144 patients admitted to the Hospital de Especialidades were included; demographic data (Table I) was collected. The mean age was 72.7 ± 6.7, and 95.1% of patients were male. Of the total patients, 13% continued to smoke and 31.3% had a history of consuming more than 10 cigarettes a day. 2.8% had no control of systemic blood pressure. A total of 146 ultrasounds were performed, 2 patients were excluded from the study because it was not technically possible to visualize the abdominal aorta. A total of 10 AAA (6.9%) were detected, all of them in men; the 93.1% (134 patients) remaining had an abdominal aorta diameter of 1.6 to 2.9 cm, which is considered normal (Table II).

The logistic regression analysis showed that active smoking is a significant predictive factor for diagnosis of abdominal aortic aneurysm, and that it increases the risk by 8.5 times compared to patients who do not smoke.

Discussion

Abdominal aortic aneurysms have an increasing incidence in the population of adults over age 65; therefore, it is of utmost importance to implement a detection method for early diagnosis and treatment, in addition to the prevention of complications associated with this condition, which can reach up to 70% in the case of emergency surgery, compared with less than 5% in patients undergoing elective surgery.

The literature has reported four randomized studies for early detection of AAA, the Multicentre Aneurysm Screening Study (MASS),¹⁰ Chichester,¹¹ Vibord,¹² and Western Australia;^13,14 concluding that screening men over 65 years gives a significant decrease in mortality in elective AAA repair and a decrease in emergency surgery.¹⁷

The MASS study included 67,800 men with an age range of 65 to 74 years, who were divided into two groups. Group 1 (n = 33 839) was given Doppler abdominal ultrasound, detecting 1333 AAA, and group 2 (or control) was not given any test; both groups were given follow-up. In the control group there were more emergency surgeries, AAA-associated mortality was 113 in the control group and 65 in the problem group (OR = 0.58, 95% CI = 0.42 - 0.78). Total mortality from all causes did not differ between the groups. The study concluded that screening programs result in decreased mortality associated with AAA. The authors recommend that the screening be carried out only in men over 65 years due to a low incidence of AAA in women.^9,10 

In Viborg, Denmark, Lindholt and Juul¹² studied a population of 12,639 men between ages 64 and 73. The results were that 512 AAA were detected. The control group (6306) underwent 31 interventions (20 emergency and 11 scheduled), died 27 of AAA, and 1019 from all causes; with screening, AAA-specific mortality is reduced by 67% and emergency surgery by 75%; the study concludes that AAA-related mortality is reduced by a screening program and for Danish men aged 64-73 years, this appears to be cost-effective. Reassessment is unjustified when the diameter of the abdominal aorta is less than 2.5 cm, but it is necessary at 5 years if the diameter is between 2.5 and 2.9 cm.¹²

In Australia, Jamrozik and Brown conducted a study involving 41,000 men between 65 and 79 years, the results were: the prevalence of AAA is 7.2%, strongly dependent on age: 4.8% between 65-69 years, 7.6% between 70-74 years, 9.7% between 75-79 years, and 10.8% between 80-83 years; aneurysm size increased with age. In relation to the diameter, out of 875 AAA discovered, 699 (80%) measured between 3 and 4.4 cm; 115 (13%) between 4.6 and 5.4 cm, and 61 (7%) equal to 5 cm or more. There was increased mortality at 30 days after emergency surgery (4/7, 24%) than after elective surgery (7/161, 4.3%). Follow-up was performed every 6-12 months when the size of the aorta was between 3 and 4.9 cm, and it was referred to surgery if it was greater than or equal to 5 cm. The study concluded that screening men between 65 and 74 years reduces mortality associated with AAA.^13,14

A review by Crochane in 2009 revealed a reduction in AAA-related mortality in men (OR = 0.60; 95% CI: 0.47 to 0.78); this analysis included surgical mortality from emergency or elective AAA repair.¹⁷ International guides recommend performing screening in all men over 65 and women under 65 with a history of smoking; however, for screening to be useful, it is necessary to first establish that in the population there is an incidence greater than 4% in preliminary studies.

The result of this study shows that the frequency of AAA in patients with risk factors in our country is 6.9% and that the most frequently encountered diameter ranges between 3 and 4 cm; aneurysms of this size are totally asymptomatic and only can be detected by imaging studies. The risk factor most associated with AAA was smoking, not so with DM2 which seems to act as a protective factor; 59% of patients had a history of hypertension and 47% of dyslipidemia. The results of this study are added to the only two studies published in Latin America (Table III), which report low percentages compared to those found in our study.^19,20

Conclusions

The reported frequency of asymptomatic AAA in patients with risk factors in our study was 6.9%, and routine detection by duplex Doppler study is suggested to identify the disease, in order to reduce morbidity and mortality.²¹

References

1. Brunkwall J, Hauksoon H, Bengtsson H, Bergqvist D, Takolander R, Bergentz SE. Solitary aneurysms of the iliac arterial system: an estimate of their frecuency of occurrence. J Vasc Surg 1989;10(4):381-4.
2. Johnston KW, Rutherfod RB, Tilson MD,Shah DM, Hollier L, Stanley JC. Suggested standards for reporting on arterial aneurysms. Subcommittee on International Society for Cardiovascular Surgery. J Vasc Surg 1991;13(3):4528.
3. PearceWH, Slaugher MS, LeMaire S, SalayapongseAN, FeinglassJ, Meporting Standards for Arterial Aneurysm, Ad Hoc Committee on reporting Standards, Society for Vascular Surgery and North American Chapter,
4. Carthy WJ, Yao JS. Aortic diameter as a function of age, gender, and body surface area. Surgery 1993; 114(4):691-7.
5. Wilmink TB, Quick CR, Day NE. The association between cigarette smoking and abdominal aortic aneurysms. J Vasc Surg 1999;30(6):1099-105.
6. Mastracci T, Cinà CS. Screening for abdominal aortic aneurysm in Canada: Review and position statement of the Canadian Society for Vascular Surgery. J Vasc Surg 2007;45(6):1268-1276.
7. Long A, Bui HT, Barbe C, HenniAH, Journet J, Metz D, Nazeyrollas P. Prevalence of abdominal aortic aneurysm and large infrarenal Aorta in patients with Acute Coronary Syndrome and Proven Coronary Stenosis: a prospective monocenter Study. Ann Vasc Surg. 2010;24(5): 602-8.
8. Lindhot JS, Vammen S, Juul S, Henneberg EW, Fastiting H. The validity of ultrasonographic scanning as screening method for abdominal aortic aneurysm, EurJ Vasc, Endovasc Sur 1999;17:472-475.
9. Bown MJ, Sutton AJ, Bell PR. Sayers RD. A meta-analysis of 50 years of ruptured abdominal aortic aneurysm repair. Br J Surg. 2002;89(6):714-730.
10. ederle FA, Simel Dl: The rational clinical examination: Does this patient have abdominal aortic aneurysm? JAMA. 1999;281(1):28:77-82.
11. Multicentre Aneurysm Screening Study group. Multicentre aneurysm screening study (MASS): cost-effectiveness analysis of screening for abdominal aortic aneurysms based on four year results from a randomized controlled trial. BMJ 2002;325(7373): 1135-1138.
12. Ashton HA, Gao L, Kim LG, Druce PS, Thompson SG, Scott RA. Fifteen- year follow-up of randomized clinical trial of ultrasonographic screening for abdominal aortic aneurysms. Br J Surg 2007;94(6): 696-701.
13. Lindholt JS, Norman P. Screening for abdominal aortic aneurysm reduces overall mortality in men. A meta-analysis of the mid-and long-term effects of the screening for abdominal aortic aneurysms. Eur J Vasc Endovas Surg. 2008;36(2):167-171.
14. Norman PE, Jamrozik K, Lawrence-Brown MM, Le MT, Spencer CA, Tuohry RJ, Parson RW, Dickinson JA. Population based randomized controlled trial on impact of screening on mortality from abdominal aortic aneurysm. BMJ.2004;329(7477):1259
15. Jamrozik K, Norman PE, Spencer CA, Parsons RW, Tuohy R, Lawrence-Brown MM, Dickinson JA. Screening for abdominal aortic aneurysm: lessons from a population-based study. Med J Aust. 2000173 (7):345-350.
16. Lee ES. Implementation o fan aortic screening program in clinical practice: implications for Screen For Abdominal Aortic Aneurysms Very Efficiently. J Vas Surg 2009; 49(5):1107- 11.
17. Lindholt J, Juul S, Fasting H, Henneberg E. Costs, benefits, and effectiveness of screening for abdominal aortic aneurysms. Results from a randomised population screening trial. European Society for Vascular Surgery, Programme and Abstract Book, XVII Annual Meeting and Course on Vascular Surgical Techniques. 2003; Vol. 63.
18. Cosford PA.C, Leng GS, Thomas J. Screening for abdominal aortic aneurysm (Review) Cochrane Database of Systematic Reviews 2007, Issue 2, Art. No.: CD002945:DOI:10.1002/14651858.CD002945.pub2.
19. Chaicof EL, Brewster DC, Dalman RL, Makaroun MS, Illig KA, Sicard GA, Timaran CH, Upchurch GR, Veith FJ, et al. The care of patients with an abdominal aortic aneurysm: The Society for Vascular Surgery practice guidelines. J Vasc Surg. 2009;50(4 suppl):S2– S49.
20. Poveda AG, Rojas DA. Detección temprana de aneurismas de la aorta abdominal mediante escáner dúplex a color. Revista Med 2007 En;15(1):61-67.
21. Grosso OA, Volberg VI, Ávalos V, Berensztein CS, Lerman J, Piñeiro DJ. Detección de aneurismas de la aorta abdominal en una población derivada para ecocardiografía transtorácica. Rev Argent Cardiol 2006;74(3):217-223.
22. FL Moll Managment of abdominal aortic aneurysms. Clinical Practice guidelines of The European Society of Vascular Surgery. Eur J Vasc Surg. 2001;41:1-58.

Enlaces refback

• No hay ningún enlace refback.