Ultrasonic Screening for the Detection of Abdominal Aortic Aneurysms

Abdominal Aortic Aneurysms

0039-6109/89 $0.00 + .20

Ultrasonic Screening for the Detection of Abdominal Aortic Aneurysms Denis S. Quill, M.Ch., F.R.C.S.I.,* Mary Paula Colgan, M.D.,t and David S. Sumner, M.D.+

Ruptured aortic aneurysms are responsible for 1. 2 per cent of deaths in men over the age of 65 and for 0.6 per cent of deaths in women of a similar age." Because aneurysm rupture is frequently not recognized as the cause of death, these figures undoubtedly underestimate the severity of the problem. It is estimated that 27 to 50 per cent of patients with ruptured abdominal aneurysms die before reaching a hospital, 24 to 58 per cent die after arriving at the hospital before operative intervention, and, of those who reach the operating room, 42 to 80 per cent die in the perioperative period, for an overall mortality rate of 78 to 94 per cent.v 25, 27, 45, 46 Despite significant advances in surgical technique, anesthesia, and postoperative care, the mortality rate from ruptured aneurysms has shown relatively little improvement. On the 'other hand, over the past 30 years, there has been a steady decline in the perioperative mortality rate associated with elective resection of abdominal aortic aneurysms. 5, 8, 14,24,43 Several institutions report mortality rates less than 1 or 2 per cent," 14, 16,33 but the average mortality rate is probably closer to 4 to 11 per cent. 23, 29, 37 After successful surgery, long-term survival is better than that in patients who have not been operated on and, in some studies, is not significantly different from that of age- and sex-matched controls. 14, 18,36,38,43,44 Clearly, if the mortality rate attributable to abdominal aortic aneurysms is to be reduced, the disease must be recognized and treated before rupture occurs. Unfortunately, the majority of aneurysms remain asymptomatic until they rupture. Most asymptomatic aneurysms are discovered incidentally on routine physical examination or by chance from calcifications visible on abdominal roentgenograms. Thus, a large proportion of potentially lethal aneurysms remain undetected. This fact has fostered interest in screening high-risk populations for aneurysmal disease." 13, 41, 42 SCREENING METHODS Although careful abdominal palpation will identify most large aneurysms, small aneurysms are easily missed, especially when the patient is obese. Moreover, a *Consultant, Regional tVascular Laboratory, tProfessor of Surgery University School

Hospital, Galway, Ireland St. James' Hospital, Dublin, Ireland and Chief, Section of Peripheral Vascular Surgery, Southern Illinois of Medicine, Springfield, Illinois

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tortuous aorta or abdominal mass may mimic an aneurysm on physical examination. Conventional radiography reveals the presence of an aneurysm in only about 56 per cent of cases and occasionally is falsely positive. 40 Thus, because aneurysms cannot reliably be detected or excluded by physical examination or by conventional abdominal roentgenograms, better diagnostic methods are required. Not only must a method accurately identify the presence or absence of the disease, but it should also be capable of defining the extent and diameter of the aneurysm. The latter requirement is particularly important, because it is generally accepted that the risk of rupture is related to the degree of dilatation. 15, 17 Arteriography, which defines only that portion of the lumen not filled with clot and not the extent of aneurysmal dilatation, is unsatisfactory as a diagnostic method. Moreover, arteriography is invasive, precluding its use as a routine diagnostic study, especially when the index of suspicion is low. B-mode ultrasonography and computed tomography (CT) are two methods that meet the criteria of an appropriate screening tool: safety, reproducibility, and a high degree of accuracy. Both can be conducted without causing the patient discomfort. Although CT scanning is somewhat more accurate, ultrasonography has the advantages of not requiring contrast media, of using no ionizing radiation, and of being less expensive;" It therefore is best suited for the initial evaluation of patients in whom aneurysmal disease is suspected and for screening patients at risk for the disease.

ULTRASONOGRAPHY Ultrasonic images of the abdominal aorta can be obtained with either a static B-mode gray-scale instrument (Fig. 1) or a real-time device (Fig. 2). The abdomen is scanned longitudinally at 1.O-cm increments from the midline and at similar intervals transversely from the xiphoid process to about 6 em below the umbilicus. Static scans have the advantage of displaying the full course of the aorta in a single longitudinal field of view. Real-time scanning is more rapid and is well adapted to studying the abdomen in oblique planes, which may be advantageous when there is excessive bowel gas or when the aorta is tortuous. Furthermore, real-time instruments are commonly available in vascular laboratories, a fact that makes them particularly well adapted for screening high-risk patients. The accuracy of ultrasound in identifying the presence or absence of an aneurysm approaches 100 per cent. 10, 20, 32, 34, 35 Maloney and associates found that the ultrasonic estimation of aneurysm diameters averaged within 0.4 em of the measurements obtained during operation," and only 3 of 40 anteroposterior diameter measurements differed by more than 1.0 em. A Cleveland Clinic study revealed

Figure 1. Static ultrasound images of a 3.9-cm abdominal aortic aneurysm. A, Crosssection. B, Longitudinal section, showing neck (N) and iliac arteries (IA).

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Figure 2. Real-time B-mode scan of 5.6-cm abdominal aortic aneurysm showing intraluminal clot.

that measurements with B-mode ultrasound were identical to operative measurements in 34 per cent of patients and were within 0.5 ern in 75 per cent. 22 The studies of Bernstein and colleagues, who followed more than 100 patients with repeated studies for as long as 6 years, suggest that ultrasonic measurements are highly reproducible." Examinations performed at intervals of 3 months rarely varied by more than 2 or 3 mm, thereby permitting accurate determination of growth rates. Ultrasound examinations are rendered more difficult by excess intestinal gas, but frequently-even i~ the presence of gaseous distention-the aneurysm is large enough to displace the overlying bowel, allowing the diagnosis to be made. Having the patient fast prior to the study will reduce this problem. Images may also be degraded by retained barium. Rarely, a patient is too obese to be studied. Nonetheless, in the majority of patients, a diagnosis can be made without preparation. Equipment problems, poor application techniques, inexperienced technicians, and lack of skill in interpreting the scans probably account for most of the errors associated with abdominal ultrasonography.

RATIONALE FOR SCREENING To predict the feasibility of a screening program, one must have an estimate of the incidence and prevalence of the disease, the cost of screening, the risk of untreated disease, and the potential benefits of surgical management. Ultimately, we are interested in balancing the cost of screening against the number of lives saved. Incidence and Prevalence of Abdominal Aortic Aneurysms Population studies from Rochester, Minnesota, and the Okanagan Valley of British Columbia indicate that the incidence (number of new cases) of abdominal aortic aneurysm is between 15 and 37 per 100,000 person-years. 8, 9 Age has a dramatic effect: the incidence in Rochester from 1971 to 1980, which was essentially zero below the age of 49, increased from 2.1 in the 40- to 49-year age group to 283 in persons over 80. 8 An appreciably higher incidence is reported in men (26 to 62 per 100,000 person-years) than in women (5 to 17 per 100,000 person-years). 8, 9 In Western Australia, the incidence in men between 65 and 74 years of age was 167

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per 100,000 person-years, a value more than five times that in women." The incidence has increased over the past 20 years, an increase largely but not entirely attributable to better diagnosis. 8, 12 Because these figures do not include asymptomatic patients whose aneurysms were not detected during life or those who died from another cause without having an autopsy, they almost certainly underestimate the true incidence. Darling and associates reported that abdominal aortic aneurysms were found in 2.0 per cent of 24,000 consecutive autopsies performed at the Massachusetts General Hospital." Other investigators, using data derived from autopsies, CT scans, or ultrasonograms, have reported a similar prevalence (number of existing cases) of about 2 to 3 per cent in un selected populations. 1, 26, 28, 30, 42 The prevalence in white males (4.2 per cent) appears to exceed that in white females, black males, and black females (all about 1.5 per cent);" Associated vascular pathology produces a population with an increased prevalence of abdominal aortic aneurysm. Patients with coronary atherosclerosis have a 5 per cent prevalence, and this rises to 10 per cent or more in those with peripheral or cerebrovascular disease. 1, 11,21,47 Patients with peripheral aneurysms have an even higher rate, approximately 40 per cent." 50 Twomey and coworkers reported a prevalence of 7.0 per cent in hypertensive men over the age of 50; but Lindholm and colleagues found only one abdominal aneurysm in 245 hypertensive patients, a prevalence of 0.4 per cent. 31,49 First-order relatives (parents, siblings, and offspring) of patients with abdominal aortic aneurysms are considerably more likely to have the disease than the general population (19.2 versus 2.4 per cent in one study). 26, 48 At the outset of a screening program, the prevalence of abdominal aneurysms in the population being surveyed will determine the yield. Thereafter, the yield will drop as existing cases are detected and managed until a baseline is reached that corresponds to the true incidence of new disease. Obviously, the number of cases identified will be higher and the dividends bigger when screening is directed toward high-risk groups.

Cost-Benefit Analysis According to the Bureau of the Census, there were 28,536,000 persons over the age of 65 in the United States in 1985. During that year, 12,499 deaths in the same age group were attributed to aneurysms. 50 The average cost of an ultrasonic scan for abdominal aortic aneurysm is about $150 in central Illinois. To scan all patients at risk would cost approximately $4.3 billion dollars, which equates to about $360,000 per life saved (provided that all patients underwent operation and there were no operative deaths). If only white men were scanned, the cost per life saved would be $212,000. Tables 1 and 2 offer a different approach to the problem. Calculations were based on the following assumptions: (1) that 30 per cent of the aneurysms detected by ultrasound would be less than 3.9 em in diameter, 50 per cent between 4.0 and 7.0 em, and 20 per cent larger than 7.0 ern;" (2) that the rupture rates in these groups would be 10 per cent, 25 per cent, and 50 per cent, respectively, and that the overall rupture rate would be 25 per cent," (3) that 40 per cent of the patients with ruptured aneurysms would undergo operation with an operative mortality rate of 50 per cent, for an overall mortality rate following rupture of 80 per cent," 25, 45, 46 and (4) that the mortality rate for elective resection would be 5 per cent. 23, 29, 37 Based on Medicare reimbursement for hospital costs, surgeon fees, and anesthesiologist fees, figures of $12,000 and $17,500 were assigned to operations for elective and ruptured aneurysms, respectively. The prevalence of ultrasonographically detected aneurysm is 2.5 per cent in Table 1 (representing an unselected population of 100,000 people over 65 years of age). If no screening were done and no aneurysms were detected prior to rupture,

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Table 1. Cost of Screening 100,000 Subjects for Abdominal Aortic Aneurysm (Prevalence = 2.5 per cent; Number of Aneurysms = 2500) Without screen or elective resection No. of ruptured aneurysms No. of operations for rupture a. No. of deaths from rupture b. Cost of operations With c. d. e. f. g. h.

0.25 x 2500 0.40 x 625 0.80 x 625 $17,500 x 250

screen, all aneurysms operated on electively No. of perioperative deaths 0.05 x 2500 Cost of operation $12,000 X 2500 Cost of screen $150 X 100,000 Total cost d + e No. of lives saved by screen a - c Cost difference, screen - no screen f - b Total cost per life saved Cost of screen per life saved

h/g el g

625 250 500 $4.4 million 125 $30.0 $15.0 $45.0 375 $40.6

million million million million

$108,000 $40,000

there would be 500 deaths attributable to aneurysms, and the cost would be $4.4 million for operation alone. On the other hand, if the total population were screened and all detected aneurysms were operated on electively, there would be 125 deaths, and the total cost would be $45.0 million; but 375 lives would be saved at a cost of $108,000 per life saved. If, however, the population were composed of patients with concomitant peripheral vascular disease in whom the prevalence of abdominal aortic aneurysm was 10 per cent, screening with ultrasound would save 1500 lives at a cost of $78,000 per life saved (Table 2). Whether these figures-admittedly based on a very crude and hypothetical mathematical exercise-represent a reasonable expenditure to save a life is a decision that rests with society. The cost of death estimated by the National Academy of Sciences is $200,000. 39 Acceptance of this figure would appear to make screening cost-effective. Similar calculations have been made by English authors. Collin concluded that it would cost £9000 to save a single life by adopting a screening program. 13 This is considerably less than the figures arrived at above, reflecting a lower cost for scanning (£5 per scan) and for operative treatment (£2000). Scott estimated a cost of £300 for each potentially lethal aneurysm identified." Our figures suggest that the cost would be $6000, again reflecting the higher cost of ultrasonography in the

Table 2. Cost of Screening 100,000 Subjects for Abdominal Aortic Aneurysm (Prevalence = 10 per cent; Number of Aneurysms = 10,000) Without screen or elective resection No. of ruptured aneurysms No. of operations for rupture a. No. of deaths from rupture b. Cost of operations

0.25 x 10,000 0.40 x 2500 0.80 x 2500 $17,500 x 1000

2500 1000 2000 $17.5 million

With screen, all aneurysms operated on electively c. No. of perioperative deaths d. Cost of operation e. Cost of screen f. Total cost g. No. lives saved by screen h. Cost difference, screen - no screen

0.05 x 10,000 $12,000 x 10,000 $150 x 100,000 d + e a - c f - b

500 $120.0 million $15.0 million $135.0 million 1500 $117.5 million

h/g e/g

$78,000 $10,000

Total cost per life saved Cost of screen per life saved

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U. S. Using $150 as the cost of a scan, Thurmond and Semler calculated that the cost of 25 to 54 ultrasound examinations plus one elective operation would equal the cost of one emergency operation for aortic aneurysm, suggesting that at a prevalence of 1.8 to 4.0 per cent, scanning would be cost-effective." Clearly, reducing the charge for each study would make ultrasonographic screening more attractive. None of these calculations addresses the issue of repeat examinations in the previously surveyed population to identify new aneurysms. If one assumes an incidence of 100 per 100,000 person-years in men over 55 years of age (a relatively high-risk group);" the cost of identifying a single new aneurysm would be $150,000 and that of identifying a potentially lethal aneurysm would be $600,000 (based on a rupture rate of 25 per cent). In lower-risk groups, this figure would be multiplied many-fold. Not infrequently, the surgeon elects not to resect an aneurysm, either because it is small or because the risk of operation is felt to be prohibitive. However, small aneurysms do rupture, and the risk of rupture appears to correlate with the rate of expansion (which averages 0.4 ern per year but can be much greater). 5, 17 During an average follow-up of 36 months, Cronenwett and colleagues found that 9 per cent of small aneurysms (mean diameter 4.0 em) ruptured and another 9 per cent expanded acutely." It therefore behooves the surgeon to monitor these patients closely with ultrasonic scanning. By serially scanning high-risk patients with small aortic aneurysms at 3-month intervals, Bernstein and Chan identified 41 per cent who required aneurysm resection based on the development of symptoms, rapid expansion, or expansion beyond a diameter of 6.0 ern. With this approach, only 4.0 per cent died of rupture or as the result of elective resection." Based on their lifetable analysis and a cost of $150 per scan, the estimated cost of scanning per patient selected for operation is about $5000. This does not seem to be excessive, as it probably represents the cost of salvaging a life.

RECOMMENDATIONS FOR SCREENING It is clear that the mortality rate of untreated abdominal aortic aneurysms is unacceptably high and that elective surgery should be considered in all patients with aneurysms larger than 4 or 5 ern. Because the majority of aneurysms remain asymptomatic and are often overlooked on physical examination, objective screening is required if all are to be identified prior to rupture. The cost -effectiveness of ultrasound screening for abdominal aortic aneurysms depends on society's perception of the value of a human life. The answer to this question is academic, because it is unlikely that mass population screening will ever be seriously considered and even less likely that it would be implemented. The individual physician, however, should keep the diagnosis in mind and screen those patients at high risk for developing aneurysms, namely patients with first-degree relatives with the disease and patients beyond the age of 50 with hypertension, coronary atherosclerosis, or peripheral vascular disease-especially when the patient is obese or otherwise has an abdomen that is difficult to palpate. Although the average cost of disclosing an aneurysm by this approach would not differ from that of mass screening of a similarly high-risk population, the expense would be dispersed and would be unrecognizable. Moreover, when the physician or surgeon manages his or her own laboratory, the cost per scan can be reduced to the point of being almost negligible if,' at the culmination of a duplex examination of the carotid or peripheral arteries, the probe is merely swept across the abdomen. The unfortunate trade-off of this restricted approach is that many potentially fatal aneurysms would

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remain undetected; yet, if generally practiced, it would undoubtedly effect some reduction in the number of ruptured aneurysms.

REFERENCES 1. Allardice JT, Allwright GJ, Wafula JMC, et al: High prevalence of abdominal aortic aneurysm in men with peripheral vascular disease: Screening by ultrasonography. Br J Surg 75:240, 1988 2. Allen PIM, Gourevitch D, McKinley J: Population screening for aortic aneurysms. Lancet 2:736, 1987 3. Anton GE, Hertzer NR, Beven EG, et al: Surgical management of popliteal aneurysms: Trends in presentation, treatment, and results from i952 to 1984. J Vase Surg 3:125, 1986 4. Armour RH: Survivors of ruptured abdominal aortic aneurysms: The iceberg's tip. Br Med J 2:1055, 1977 5. Bernstein EF, Chan EL: Abdominal aortic aneurysms in high risk patients. Ann Surg 200:255, 1984 6. Bernstein EF, Dilley RB, Randolph HF III: The improving outlook for patients over 70 years of age with abdominal aortic aneurysms. Ann Surg 207:318, 1988 7. Bernstein EF, Dilley RB, Goldberger LE, et al: Growth rates of small abdominal aortic aneurysms. Surgery 80:765, 1976 8. Bickerstaff LK, Hollier LH, Van Peenan HJ, et al: Abdominal aortic aneurysms: The changing natural history. J Vasc Surg 1:6, 1984 9. Bowers D, Cave WS: Aneurysms of the abdominal aorta: A twenty year study. J R Soc Med 78:812, 1985 10. Brewster DC, Darling RC, Raines JK, et al: Assessment of abdominal aortic aneurysm size. Circulation 56(suppl 2):11-164, 1977 11. Cabellon S Jr, Moncrief CL, Pierre DR, et al: Incidence of abdominal aortic aneurysms in patients with atheromatous arterial disease. Am J Surg 146:575, 1983 12. Castleden WM, Mercer JC, Paton R, et al: Abdominal aortic aneurysms in Western Australia: Descriptive epidemiology and patterns of rupture. Br J Surg 72:109, 1985 13. Collin J: Screening for abdominal aortic aneurysms. Br J Surg 72:851, 1985 14. Crawford ES, Saleh SA, Babb ]W III, et al: Infrarenal abdominal aortic aneurysm: Factors influencing survival after operation performed over a 25-year period. Ann Surg 193:699, 1981' 15. Cronenwett JL, Murphy TF, Zelenock GB, et al: Actuarial analysis of variables associated with rupture of small abdominal aortic aneurysms. Surgery 98:472, 1985 16. Darling RC, Brewster DC: Elective treatment of abdominal aortic aneurysms. World J Surg 4:661, 1980 17. Darling RC, Messina C~, Brewster DC, et al: Autopsy study of unoperated abdominal aortic aneurysms. The case for early resection. Circulation 56(suppl 2):11-161, 1977 18. Fielding JWL, Black J, Ashton F, et al: Diagnosis and management of 528 abdominal aortic aneurysms. Br Med J 283:355, 1981 19. Gomes MN, Choyke PL: Pre-operative evaluation of abdominal aortic aneurysms: Ultrasound or computed tomography? J Cardiovasc Surg 28:159, 1987 20. Graeve AH, Carpenter CM, Wicks JD, et al: Discordance in sizing of abdominal aortic aneurysm and its significance. Am J Surg 144:627, 1982 21. Graham M, Chan A: Ultrasound screening for clinically occult abdominal aortic aneurysm. Can Med Assoc J 138:627, 1988 22. Hertzer NR, Beven EG: Ultrasound measurement and elective aneurysmectomy. JAMA 240:1966, 1978 23. Hertzer NR, Avellone JC, Farrell CJ, et al: The risk of vascular surgery in a metropolitan community, with observations on surgeons' experience and hospital size. J Vase Surg 1:13, 1984 24. Hicks GL, Eastland MW, DeWeese JA, et al: Survival improvement following aortic aneurysm resection. Ann Surg 181:863, 1975 25. Ingoldsby CJH, Wujanto R, Mitchell JE: Impact of vascular surgery on community mortality. Br J Surg 73:551, 1986

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26. Johansen K, Koepsell T: Familial tendency for abdominal aortic aneurysm. JAMA 256:1934, 1986 27. Johansson G, Swedenborg J: Ruptured abdominal aortic aneurysms: A study of incidence and mortality. Br J Surg 73:101, 1986 28. Johnson G Jr, Avery A, McDougal G, et al: Aneurysms of the abdominal aorta: Incidence in blacks and whites in North Carolina. Arch Surg 120:1138, 1985 29. Johnston KW, Scobie TK: Multicenter prospective study of nonruptured abdominal aortic aneurysms I: Population and operative management. J Vase Surg 7:69, 1988 30. Leopold GR, Goldberger LE, Bernstein EF: Ultrasonic detection and evaluation of abdominal aortic aneurysms. Surgery 72:939, 1972 31. Lindholm L, Ejlertsson G, Forsberg L, et al: Low prevalence of abdominal aortic aneurysm in hypertensive patients: A population based study. Acta Med Scand 218:305, 1985 32. Maloney JD, Pairolero PC, Smith BF Jr, et al: Ultrasound evaluation of abdominal aortic aneurysms. Circulation 56(suppl 2):11-80, 1977 33. McCabe CJ, Coleman WS, Brewster DC: The advantage of early operation for abdominal aortic aneurysm. Arch Surg 116:1025, 1981 34. Mulder DS, Winsberg F, Cole CM, et al: Ultrasonic "B" scanning of abdominal aneurysms. J Thorac Surg 16:361, 1973 35. Nusbaum JW, Friemanis AK, Thomford NR: Echography in the diagnosis of abdominal aortic aneurysm. Arch Surg 102:385, 1971 36. O'Donnell TF, Darling RC, Linton RR: Is 80 years too old for aneurysmectomy? Arch Surg 111:1250, 1976 37. Pilcher DB, Davis JH, Ashikaga T, et al: Treatment of abdominal aortic aneurysm in an entire state over 7V2 years. Am J Surg 139:487, 1980 38. Reigel MM, Hollier LH, Kazmier FJ, et al: Late survival in abdominal aortic aneurysm patients: The role of selective myocardial revascularization on the basis of clinical symptoms. J Vase Surg 5:222, 1987 39. Richardson EL: The Creative Balance. New York, Holt, Rinehart & Winston, 1977, p 138 40. Robicsek F: The diagnosis of abdominal aneurysms. Surgery 89:275, 1981 41. Santiago F: Screening for abdominal aortic aneurysms: The U-boat in the belly. JAMA 258:1732, 1987 42. Scott RAP: Ultrasound screening in the management of abdominal aortic aneurysms. Int Angiol 5:263, 1986 43. Soreide 0, Lillestol J, Cristensen 0, et al: Abdominal aortic aneurysms: Survival analysis of four hundred thirty-four patients. Surgery 91:188, 1982 44. Szilagyi DE, Smith RF, DeRusso FJ, et al: Contribution of aortic aneurysmectomy to prolongation of life. Ann Surg 164:678, 1966 45. Taylor LM, Porter JM: Basic data related to clinical decision-making in abdominal aortic aneurysms. Ann Vasc Surg 1:502, 1886 46. Thomas PRS, Stewart RD: Abdominal aortic aneurysm. Br J Surg 75:733, 1988 47. Thurmond AS, Semler HJ: Abdominal aortic aneurysm: Incidence in a population at risk. J Cardiovasc Surg 27:457, 1986 48. Tilson MD, Seashore MR: Fifty families with abdominal aortic aneurysms in two or more first-order relatives. Am J Surg 147:551, 1984 49. Twomey A, Twomey E, Wilkins RA, et al: Unrecognized aneurysmal disease in male hypertensive patients. Int Angiol 5:269, 1986 50. US Department of Health and Human Services: Vital Statistics of the United States 1985, Vol II: Mortality Part A. Hyattsville, National Center for Health Statistics, 1988 51. Vermilion BD, Kimmins SA, Pace WG, et al: A review of one hundred forty-seven popliteal aneurysms with long term follow-up. Surgery 90:1009, 1981 David S. Sumner, M.D. Department of Surgery Southern Illinois University P.O. Box 19230 Springfield, Illinois 62794-9230