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Unique Identifier 97188949
Authors: Chang JB. Stein TA. Liu JP. Dunn ME.
Institution: Long Island Vascular Center, Roslyn, NY 11576, USA.
Title: Risk factors associated with rapid growth of small abdominal aortic aneurysms.
Source: Surgery. 121(2)117-22, 1997 Feb.
Abstract: BACKGROUND: Approximately 50% of patients who have a ruptured abdominal aortic aneurysm will die. To identify those patients who may be at high risk for rupture, we determined the risk factors for the rapid expansion of the aorta. METHODS: The growth of 514 aneurysmal aortas was followed in this study. The size of each was measured by ultrasonography at 6- to 12-month intervals until a critical size was reached or a rapid expansion of the aorta occurred. Possible risk factors for rapid expansion were determined from both initial evaluation and clinical laboratory results. RESULTS: The initial size varied from 2.5 cm to 6.0 cm. The expansion rate of the aorta was 0.5 cm/yr or less in 401 patients (78%), between 0.5 and 1.0 cm/year in 50 patients (10%), and 1.0 cm/year or more (rapid expansion) in 63 patients (12%). Elective repair of aneurysms was done before rupture. Multivariate analysis indicated that the risk factors associated (p < 0.03) with rapid expansion were advanced age, severe cardiac disease, previous stroke, and history of cigarette smoking. The incidence for rapid expansion increased (p < 0.01) in older patients with aneurysms larger than 3 cm and in younger patients with aneurysms larger than 4 cm. CONCLUSIONS: Risk factors associated with rapid expansion of the aorta have been determined and may help identify the patient at high risk for rupture. Ultrasonographic surveillance should be performed more frequently in these patients to help prevent rupture.

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Unique Identifier 94016996
Authors: Hallett JW Jr. Naessens JM. Ballard DJ.
Institution: Division of Vascular Surgery, Mayo Clinic, Rochester, MN 55905.
Title: Early and late outcome of surgical repair for small abdominal aortic aneurysms: a population-based analysis.
Source: Journal of Vascular Surgery. 18(4)684-91, 1993 Oct.
Abstract: PURPOSE: Whether small abdominal aortic aneurysms (AAAs) (< or = 5 cm in diameter) should be repaired early to enhance late survival remains controversial. Long-term population-based data on the surgical outcome for small AAAs may help to establish practice guidelines until randomized clinical trials are completed. METHODS: To examine an entire community experience with small AAAs, we conducted a population-based analysis of the recognition, reasons for operation, perioperative mortality rates, and late survival in Olmsted County, Minnesota. RESULTS: The incidence of recognized small AAAs increased thirtyfold during a 30-year period. The propensity to repair small AAAs also increased during the same period. Eventually one third of small AAAs were repaired. The primary reasons for surgical consultation and operation were presence of the aneurysm (49%), expansion on serial examination (28%), nonspecific abdominal or back symptoms (18%), and excessive patient anxiety about the aneurysm (5%). Community operative mortality rates for small AAAs were low (2.6%) compared with those for large aneurysms (5.5%) (p = 0.65). However, the observed 5-year survival rate for the group undergoing repair of small aneurysms was 62%, which was significantly less than the 83% expected survival for the general population (p < 0.05). Relative survival for the operated small and large aneurysms was similar. The primary cause of death for both groups was myocardial infarction. CONCLUSIONS: The results of our population-based analysis indicate that early operative results for elective repair of small AAAs are excellent, but late survival remains significantly impaired by coronary heart disease. Consequently, our data question whether early repair of small AAAs will enhance late survival. Until randomized clinical trials on management of small AAAs are completed, most small AAAs should be monitored for expansion and operated on electively when they approach or enter the range of 5 to 6 cm in good-risk patients.

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Unique Identifier 93059913
Authors: Katz DA. Littenberg B. Cronenwett JL.
Institution: Department of Medicine, Veterans Administration Medical Center, White River Junction, VT 05001.
Title: Management of small abdominal aortic aneurysms. Early surgery vs watchful waiting.
Source: JAMA. 268(19)2678-86, 1992 Nov 18.
Abstract: OBJECTIVE--To compare two clinical strategies for the management of small abdominal aortic aneurysms (AAAs) less than 5 cm in diameter: early surgery (repair small AAAs when diagnosed) and watchful waiting (measure AAA size every 6 months and repair when the diameter reaches 5 cm). DATA SOURCES--We reviewed data from an earlier longitudinal study of patients with small AAAs to estimate incidence rates of rupture or acute expansion. Estimates for other parameters in the model were obtained by searching the medical literature (MEDLINE, 1966 to present). DATA SYNTHESIS--We constructed a Markov decision tree to compare early surgery with watchful waiting in patients with asymptomatic AAAs less than 5 cm in diameter, with respect to long-term survival in quality-adjusted life years. The average annual rates of rupture or acute expansion for AAAs with a maximal transverse diameter of less than 4.0, 4.0 to 4.9, and at least 5.0 cm, are 0, 3.3, and 14.4 events per 100 patient-years of observation, respectively. At an average rupture rate of 3.3 events per 100 patient-years and an average operative risk for elective surgery (4.6%, 30-day mortality), our model predicts that early surgery improves survival in patients who present with a 4-cm AAA. The benefit of early surgery decreases with increased age at presentation. If the average rupture rate for AAAs less than 5 cm is assumed to be low (eg, 0.4 event per 100 patient-years), watchful waiting if favored, particularly as operative risk increases. The decision in this subgroup, however, is sensitive to possible future increases in operative risk. CONCLUSIONS--In the majority of scenarios that we examined, early surgery is preferred to watchful waiting for patients with AAAs less than 5 cm in diameter. Watchful waiting is generally favored, however, for patients with a low risk of AAA rupture or acute expansion, including those patients who present with very small AAAs (eg, < 4 cm). More accurate data concerning the rupture risk of AAAs less than 5 cm would improve clinical decision making.

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