Presentation and patterns of aortic aneurysms in young patients

Transcription

1 Presentation and patterns of aortic aneurysms in young patients Satish C. Muluk, MD, Jonathan P. Gertler, MD, David C. Brewster, MD, Richard P. Cambria, MD, Glenn M. LaMuraglia, MD, Ashby C. Moncure, MD, R. Clement Darling, MD, and William M. Abbott, MD, Boston, Mass. Purpose: Although aortic aneurysm (AA) is primarily a disease of older age groups, younger (< 51 years) patients infrequently are admitted requiring AA surgery. We sought to compare the characteristics of these patients with those of a randomly selected group of older patients with AA. Methods: We identified 26 patients with AA (group I) under age 51 (mean age 44.8) treated surgically between 1977 and 1993, after excluding patients with acute aortic dissection, traumatic pseudoaneurysms, and ascending or arch aneurysms, and compared them with 75 randomly selected patients with AA between the ages of 65 and 75 (mean age 70.3) who were surgically treated during the same time period (group II). Results: Prevalence of hypertension, diabetes, coexisting heart, kidney, or occlusive peripheral vascular disease was similar between the two groups, and familial aneurysm rates and sex distribution did not differ significantly. More patients in group I had symptoms at the time of presentation (46% vs 6.7%,p < 0.001), and they also had larger A_As (6.9 cm vs 6.0 cm, p = 0.01). Definable causes of aneurysmal disease, such as Takayasu's, Cogan's, and Marfan syndromes, were more common among the young patients (23% vs 0%, p = 0.01), but most (77%) young patients did not have an identifiable syndrome associated with their aneurysm disease. Group I had a marked shift toward proximal aneurysms, defined as involvement of juxtarenal, suprarenal, or thoracoabdominal aorta (46% vs 18% in group II, p < 0.01). This difference persisted even when aneurysms associated with the above syndromes were excluded from consideration (p = 0.02). Cigarette smoking was much more common among the young patients (83% vs 51% in group II, p < 0.01). Smoking in group II was associated with more extensive aneurysm disease (p ). Conclusions: Aneurysmal disease presenting in the young adult is more likely to be symptomatic and associated with more proximal aortic involvement than aneurysmal disease in older patients. Smoking appears to play an important role in the pathogenesis of aneurysmal disease in the young patient and was associated in our study with more proximal aneurysms among older patients. A subgroup of patients at risk for early and aggressive aneurysm disease is suggested by these data. (J VAsc SURG 1994;20:880-8.) Aneurysmal dilation of the aorta is primarily a disease of the elderly. However, there have been scattered reports of aortic aneurysm (AA) among young adults. 16 The case report format of these From the Division of Vascular Surgery, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston. Presented at the Eighth Annual Meeting of the Eastern Vascular Society, Montrdal, Qudbec, Canada, May 12-15, Reprint requests: Jonathan P. Gertler, MD, Massachusetts General Hospital, Ambulatory Care Center, Suite 464, 15 Parkman St., Boston, MA Copyright 1994 by The Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter /94/$ /6/59850 previous publications do not allow one to draw any general conclusions about AA in young adults, although they do suggest collectively that the clinical features of AA are different when the entity presents at a younger age. Our own anecdotal experience with such patients also suggested important differences between young and old patients with AA. We undertook in this study to delineate etiologic factors, clinical presentation, AA extent, and clinical outcome in all 26 young adult (age 50 or less) patients who underwent AA surgery at the Massachusetts General Hospital (MGH) over the last 16 years. Over the same time period, approximately 6000 total AA operations were performed at the MGH. We compared these young patients with a 880

2 Volume 20, Number 6 Aluluk et al. 881 Table I. Demographic and clinical characteristics of young adult and control aortic aneurysm patients All young AA (group I) p Value Older AA (group 11) p Value Nonspeciflc young AA No. of patients Age (mean, yr.) 44.8 p < p < Male/female ratio 5.6:1 N S 3.5:1 NS 19:1 Clinical characteristics Symptoms* 46% p < % p < % Hypertension 46% NS 58% NS 40% Diabetes mellitus 3.9% NS 8.0% NS 5.0% Tobacco use 83% p < % p < % Heart disease 24% NS 33% NS 30% Carotid artery disease 8.0% NS 11% NS 10% Kidney disease 20% NS 15% NS 15% Lung disease 4% p = % p = % LE occlusive disease 19% NS 27% NS 20% Hyperlipidemia 3.9% NS 0% NS 5% Defined cause? 23% p = % - 0% Family history of AA 7.7% NS 11% NS 10% LE, Lower extremity. *At time of presentation with AA. J-Known connective tissue or vascnlitic cause of AA. Statistical data derived by comparing each young patient group with the older patient group. Table II. Detailed assessment of smoking among patients with AA Smoking category Group I (young patients with AA) Group II (older patients with AA) Never smoked (nonsmoker) 4 35 Quit > 10 years PTA 0 5 Quit < 10 years PTA 3 6 < 1 pack per day 4 11 > 1 pack per day Total PTA, Prior to admission. Difference in distributions significant by Chi-square testing (p < 0.01) Data not available on two group I patients (of 26) and three group II patients (of 75). randomly selected group of 75 older (age 65 to 75) patients with AA. MATERIAL AND METHODS Patient identification. We reviewed the records from 1977 to 1993 of all patients who were under age 51 at the time of admission to the surgical service and carried a diagnosis of AA. After excluding patients undergoing redo AA operations, as well as those who had acute aortic dissection, coarctation, aortic pseudoaneurysm or tear, and ascending or arch aortic aneurysms, we identified 26 patients for detailed study (group I). The same exclusionary criteria were applied to the much larger list of patients with AA aged between 65 and 75 who were treated over the same time period. With a random number generator, 75 patients were selected from this list (group II). Data collection. Demographic data, including risk factors and associated diseases (hypertension; diabetes; heart, carotid artery, kidney, and pulmo- nary disease) were classified and graded according to the suggested standards for reports dealing with lower extremity ischemia by the Ad Hoc Committee on Reporting Standards of the SVS/NA-ISCVS. 7 A slight modification of these suggested standards was used to classify cigarette smoking. Specifically, patients were placed into one of five categories: never smoked, quit longer than 10 years before admission, quit less than/equal to 10 years before admission, smoking less than 1 pack per day at admission, smoking more than 1 pack per day at admission. Except when indicated otherwise, we used the term nonsmoker to refer to patients who never smoked. Data on associated lower extremity vascular disease, family history of AA, and definable causes of AA disease (e.g., Marfan and Takayasu's syndromes) were also recorded. Maximum AA size was determined from ultrasonography or computed tomography (CT), and aneurysm extent was assessed from preoperative CT and operative findings. Pathology

3 882 Muluk et al December 1994 records and reports of the gross anatomic findings were reviewed. Perioperative morbidity and mortality data were available in all cases, and late follow-up information was recorded when available. We adhered to the SVS/NA-ISCVS suggested standards for reporting on arterial aneurysms.8 RESULTS Fig. 1 shows the age distribution for the two groups in the study. The means for these distributions are shown in Table I. The table also summarizes several of the demographic and clinical characteristics of the patients from the two groups. There was no statistically significant difference in sex distribution, presence of hypertension, diabetes mellitus, heart disease, carotid artery occlusive disease, kidney disease, lower extremity occlusive disease, or hyperlipidemia between the two groups. Additionally, there was no statistically significant difference in the finding of a positive family history of AA. Documented pulmonary dysfunction was relatively infrequent in both groups, but this finding was more common in group II (25% vs 4% in group I, p = 0.02). The last two columns of Table I show data for the young patients after excluding those who had a well-defined cause of AA; included also are the p values for comparison of this modified group to the older patient group. As the table shows, the elimination of the six patients with well-defined causes does not substantively alter the demographic and clinical characteristics of the young patients. Patients in group I more frequently were admitted with symptomatic aneurysms (46% vs 6.7% in group II, p < 0.01). The presenting symptom was pain related to the AA in 11 of 12 patients in symptomatic group I (including 2 with ruptured aneurysms), and embolization from the AA in the remaining patient. A well-defined vasculitic or connective tissue etiologic syndrome could be identified in more of the young patients (23% vs 0% in group II, p = 0.01). These entities were Marfan (four cases), Cogan's (one case), and Takayasu's (one case) syndromes. Two of the patients with Marfan syndrome had thoracoabdominal AAs, and in subsequent years, both had development of aortic arch aneurysms. The other two patients with Marfan syndrome had infrarenal AAs, although one underwent repair of a more proximal AA 2 years later. Cogan's syndrome is characterized by nonsyphilitic interstitial keratitis together with vestibuloauditory symptoms, and may be accompanied by a systemic vasculitis involving both large and small vessels. Takayasu's syndrome is a well-known entity consisting of inflammatory disease of mediumand large-sized arteries. In our series, both patients with Cogan's and Takayasu's syndromes were admitted with thoracoabdominal AAs. The remaining patients in group I (77%) and all of the patients in group II, had nonspecific AA, accompanied by atherosclerotic changes of the aorta, as documented by clinical, gross, and pathologic features. The aneurysms found among group I patients were larger than those seen in group II (6.9 cm vs 6.0 cm, p ). However, we found that the symptomatic presentation among the young patients with AA did not correlate with increasing AA size, because the patients in symptomatic group I actually had a smaller AA diameter (6.3 cm) than the patients in asymptomatic group I (mean AA diameter of 7.4 cm). Thus, although the asymptomatic AA in group I were significantly larger than all group II AA (7.4 cm vs 6.0 cm, p < 0.01), there was no significant difference between sizes of the symptomatic AA in group I and all group II AA (6.3 cm vs 6.0 cm, NS). Fig. 2 also shows that the AA found among the young patients were significantly more extensive (p < 0.01), with an increased incidence of thoracoabdominal aneurysms. This association between proximal AA and patient group was statistically significant even when known collagen disorders were excluded and only nonspecific AA were considered (p = 0.02). Cigarette smoking was significantly more common in group I (83% vs 51% in group II,p < 0.01). More detailed assessment of cigarette usage (Table II), with use of the grading system described above, confirmed the significantly higher consumption of cigarettes by patients in group I (p < 0.01). Further analysis (Fig. 3) of cigarette usage in group II revealed a statistically significant association between smoking and aneurysm extent within that group. Only 5.4% of nonsmokers had AA involving the suprarenal and thoracic aorta, whereas 26% of smokers had proximalaa (p = 0.04). No significant association between smoking and AA extent was found among the young patient group, but this may be attributable to the rather small number of nonsmoking young patients (only four). Fig. 4 is a scatter plot that depicts the correlation between smoking and AA extent among the older patients ( + ). The young patients are also shown (o). We found that the 30-day operative mortality rate was significantly higher among patients in group I (11.5% vs 0% in group II, p = 0.01), but we found no significant difference after stratifying for aneurysm

4 JOURNAL OF VASCULAR SUKGERY Volume 20, Number 6 Muluk et al. 883 r- e~ 37 ~ 39 ~ ~ ~ ~ ~ ~ ~ Age c e~ :U= O Age (yrs) Fig. 1. Age histograms for patients in group I (A) and group II (B). extent. Of the three deaths in group I, two occurred after thoracoabdominal reconstruction, and one occurred in a patient with a tender infrarenal AA who also had severe cirrhosis. Surgical morbidity rates were comparable for both groups (13% in group I, 7.7% in group II). Long-term follow-up was available in 65% of patients in group I (median follow-up 61.3 months), and 60% of patients in group II (median follow-up 33.5 months). Among the patients in whom follow-up was available, we found no difference in late morbidity or mortality rates. DISCUSSION AA is uncommon before the sixth decade of lift, as indicated by the small proportion of patients in the total surgical AA group at the MGH who were younger than 51 years (0.4%). Our study suggests several interesting clinical features of this subgroup,of patients with AA. Despite the younger age of patients in group I, the prevalence of most of the risk factors and associated diseases we analyzed was not significandy different between the two groups. One exception to this was the higher occurrence of pulmonary dys-

5 1OURNAL OF VASCULAR SURGERY 884 Muluk et al. December mean size=6.9 cm mean size=6.0 cm.= : i Q.= I: : iiiiiiil iiiiiiiiii!~iiiiiii!i+~i!!iiiii!iiiiiiiiiii!il iiiiiiiiiiiiiiii!!iii::iiiiiiiiiiiiiiiiill!!1 ii!i!iiiiii:iiiiiiiiililili!i!iiiiiiiiilili! ::::::::::::::::::::::::::::::::::::::... ~:...,.:.i... i~iiiiiiiiiiiiiii[ii!iiiiiiiiiiiiiiiiiii~i!iiiil... ~:~,~:~:~:~: :.:.:.::... iii!!iiiiiiiiii!iiiiiiiiiiiiiii~iiiiiiiiiiiiiiil :!,:!:~:~,:!,!,~!7:?!:~:,!~!! i!i!!;!...!i! iiiiiiiiiiii!iii?ii?i?iii Group I _ Group II B Infrarenal [ mjuxta- & Suprarenal [] Thoracoabdom na Fig. 2. Distribution of aneurysm type among patients in group I and group II. Difference in distribution is statistically significant (p < 0.01) '! i ) == g Smokers Nonsmokers Fig. 3. Percentage of group II smokers and nonsmokers with proximal (juxtarenal, suprarenal, or thoracoabdominal) AA. Difference in percentages is statistically significant (p = 0.04). function in group II (Table I). However, we noted that more patients in group II had undergone formal pulmonary function testing (40% vs 7.7% in group I), possibly leading to a higher chance of having documented dysfunction among patients in group I. Alternatively, the time to development of lung disease may exceed the time to AA development in heavy smokers with a predisposition to AA formarion. One important difference between the two groups was the significantly higher prevalence of smoking among the younger patients with AA (Table I). Several reports 9,1 have demonstrated the increased risk of AA in smokers. The mechanism of acceleration of AA formation in smokers may be enhancement of aortic elastase activity.ll'iz Our study raises the possibility of an even greater role for smoking in the development of AA in young patients. Although the cause of AA is undoubtedly multifactorial, 9 our data suggest that the relative importance of smoking may be greater in young patients with AA than in older patients. Interestingly, as Figs. 3 and 4 show, we found that smoking was associated with development of proximal AA (defined as involvement of the aorta above the infrarenal segment) among patients in group II. To our knowledge, such an association has not been previously reported. The possibility that the difference in smoking prevalence between the two groups was merely a reflection of varying age-related smoking prevalences in the normal population must be considered. However, data from the 1987 national health sur-

6 IOURNAL OF VASCULAR SURGERY Volume 20, Number 6 Muluk et al. 885 Smoke~ Nonsmokers 00000~ I O0 + Thoracoabdominal x O Juxta/supra-renal O infrarenal Fig. 4. Scatter plot depicting AA extent and smoking history of group I (o) and group II ( + ) patients. Twenty-four group I patients (of 26) are depicted because of lack of smoking data on 2 young patients. See text for details of statistical analysis. vey 13 shows that the prevalence of smoking in the general population did not vary significantly between the ages of 25 and 74. In fact, among men in the survey, smoking prevalence increased with age in the range of 25 to 74 years (the reverse of the pattern seen in our study). Somewhat unexpectedly, we did not detect any significant difference in family history of AA between the two groups. However, in this retrospective study, family history data may not be entirely reliable, especially because the importance of familial AA disease has been widely recognized only in the last several years. Other reports about AA in young adults 2,a,s,6 have emphasized the importance of connective tissue disorders and vasculitic causes of AA in these patients. We also found a higher occurrence of such disorders among our patients in group I (Table I). However, the great majority (77%) of our young patients with AA had nonspecific AA, indistinguishable from those seen in the older patients. We found that mean AA size in young patients was nearly 1 cm greater than in older patients (6.9 cm vs 6.0 cm, p = 0.01). Additionally, patients in group I had a marked shift toward proximal AA, as shown in Fig. 2. Nearly 40% had thoracoabdominal AA. This shift is not simply a result of the higher prevalence of known connective tissue and vasculitic disorders among the young patients; even after these patients are excluded, a statistically signifcant shift is found (p = 0.02). Because ours is a tertiary care referral center, the possibility of selection bias must be considered. It is likely that tertiary care centers see a higher proportion of parents with extensive AA, and thus reports such as ours may overestimate the frequency of such lesions. However, we do not believe that selection bias explains the age-related difference in AA extent found in this series. A striking feature of the AAs in patients in group I was the high prevalence of symptoms at the time of presentation (Table I). It is noteworthy that the symptomatic presentation among patients in group I cannot be explained by larger AA size. Although mean AA diameter was significantly greater among patients in group I overall, the patients in symptomatic group I had a mean AA diameter of only 6.3 cm (not significantly different from the mean size of group II aneurysms, 6.0 cm). The higher frequency

7 886 Muluk et al. December 1994 of symptomatic presentation among the young patients may result from the lack of detection of asymptomatic AA in this age group. AA disease is not normally sought in these young patients, and these individuals may also be expected to have fewer studies leading to incidental AA detection (e.g., ultrasonography, intravenous pyelography). Recent studies have cast doubt on the traditional concept of atherosclerosis as the primary cause of most AAs.14~6 Considerable evidence now exists that AAs are at least partly the result of genetic susceptibility In addition, many investigators now accept an imbalance between aortic wall proteases and antiproteases as a possible etiologic factor The presence of aggressive and extensive aneurysms in a younger age group, and the demonstration of a possible association with smoking, underscores the fact that penetrance of the predisposing genetic factors varies widely in the population. In conclusion, our study demonstrates that aneurysmal disease presenting in the young adult is more likely to be symptomatic, of larger presenting AA size, and with more proximal aortic involvement than aneurysmal disease in older patients. Our data also suggest a larger role for smoking in the development of AA in young patients than in older patients, as well as an association between smoking and increased AA extent. REFERENCES 1. Occhionorelli S, Mascoli F, Romano D, et al. Aneurysm of the abdominal aorta and stenosis caused by compression of the celiac tripod in a young woman with tuberous sclerosis and previous mesoblastic nephroma. Minerva Chir 1991;46: Myrmel T, Vaage J. Congenital abdominal aortic aneurysm in a young adult: case report. Eur J Surg 1991;157: Locufier JL, Bosschaerts T, Barthel J, Delwarte D, Barroy IP. Aneurysm of the descending thoracic aorta in a young woman. J Cardiovasc Surg (Torino) 1989;30: Hirata Y, Saku K, Sasaguri M, Higashi Y, Ikeda M, Arakawa K. Abdominal aortic aneurysm of unknown origin and renovascular hypertension in a 25-year-old male. Jpn Heart J i989;30: Nardella L, Belgrano EA, Palladino F, Ferraro S. Aneurysm of the abdominal aorta in a young woman. Atherosclerotic or inflammatory in origin? Int Aaagiol 1988;7: Sterpetti AV, Hunter WJ, Schultz RD. Congenital abdominal aortic aneurysms in the young. Case report and review of the literature. J VAsc SuR~ 1988;7: Rutherford RB, Flanigan DP, Gupta SK, et al. Suggested standards for reports dealing with lower extremity ischemia: prepared by the Ad Hoc Committee on Reporting Standards, Society for Vascular Surgery/North American Chapter, International Society for Cardiovascular Surgery. ] VASC SURG I986;4: Johnston KW, Rutherford RB, Tilson MD, et al. Suggested standards for reporting on arterial aneurysms: prepared by the Subcommittee on Reporting Standards for Arterial Aneurysms, Ad Hoc Committee on Reporting Standards, Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery. J VAsc SURG 1991;13: Reilly JM, Tilson MD. Incidence and etiology of abdominal aortic aneurysms. Surg Clin North Am 1989;69: McGill HC Jr. The cardiovascular pathology of smoking. Am Heart J 1988;115: Cohen JR, Saffati I, Wise L. The effect of cigarette smoking on rabbit aortic elastase activity. J Vase SFRG 1989;9: Cannon DJ, Read RC. Blood elastolytic activity in patients with aortic aneurysm. Ann Thorac Surg 1982;34: Schoenborn CA. Smoking and other tobacco use: United States, In: Vital and Health Statistics, Series i0: Data from the National Health Survey, No US Department of Health and Human Services (DHI-IS Publication No. (PHS) ), 1989: Cohen J. Pathogenesis of aortic aneurysms. Perspect Vasc Surg 1990;3: Dobrin PB. Pathophysiology and pathogenesis of aortic aneurysms: current concept. Surg Clin North Am 1989;69: Tilson MD, Aortic aneurysms and atherosclerosis [editorial; comment]. Circulation 1992;85: Majumder PP, St Jean PL, Ferrell RE, Webster MW, Steed DL. On the inheritance of abdominal aortic aneurysm. Am J Hum Genet 1991;48: Tilson MD,Seashore MR. Human genetics of the abdominal aortic aneurysm. Surg Gynecol Obstet 1984;i58: i i9. Tilson MD. Decreased hepatic copper levels. A possible chemical marker for the pathogenesis of aortic aneurysms in man. Arch Surg 1982;117: Collin I, Walton J. Is abdominal aortic aneurysm familial? Br Med I 1989;299: Reilly JM, Tilson MD. Incidence and etiology of abdominal aortic aneurysms. Surg Clin North Am i989;69: Dobrin PB, Baker WIt, Gley WC. Elastolytic and collagenolytic studies of arteries. Implications for the mechanical properties of aneurysms. Arch Surg 1984;119: Dobrin PB, Schwarcz TH, Baker WH. Mechanisms of arterial and aneurysmal tortuosity. Surgery 1988;104: Cohen JR, Mandell C, Chang JB, Wise L. Elastin metabolism of the infrarenal aorta. J VAsc SURG 1988;7: Cronenwett JL, Murphy TF, Zelenock GB, et al. Actuarial analysis of variables associated with rupture of small abdominal aortic aneurysms. Surgery 1985;98: Reilly JM, Brophy CM, Tilson MD. Characterization of an elastase from aneurysmal aorta which degrades intact aortic elastin. Ann Vase Surg 1992;6: Submitted May 31, 1994; accepted Aug. 11, i994.

8 Volume 20, Number 6 Aluluk et al. 887 DISCUSSION Dr. lack L. Cronenwett (Lebanon, N.H.). Drs. Muluk and Gertler have drawn on the extensive vascular experience at the MGH during the last 17 years to identify an interesting group of younger patients with AA. Although the mean age of these patients was only 45, it was interesting to note that they had atherosclerotic risk factors comparable to a much older control group of 70-year-old patients. This raises the question of whether AA in younger patients are of a different cause, or whether they are simply accelerated in development by premature risk factors such as hypertension. Although it is increasingly clear that atherosclerosis is not a sufficient explanation for the cause of aneurysms, it is also true that severe atherosclerotic degeneration usually accompanies nonspecific aneurysm formation in the elderly. Thus I am curious to know whether pathologic examination of aortic tissue from these young patients showed similar advanced atherosclerosis. I was struck by the fact that the prevalence of smoking was much higher in younger patients than in older patients in this study. Interestingly, the same trend is seen across the entire United States population because the prevalence of smoking is approximately 30% for 45-year-old patients but decreases to 10% for 70-year-old patients. Thus, although patients with AA have a greater smoking prevalence than the normal population, the increased prevalence in younger patients appears to mirror the general population. Based on this finding, do the authors believe that smoking has any specific implications for the cause of aneurysms in younger patients? I was also interested in the new observation that more proximal AA were correlated with increased cigarette smoking in older patients. The manuscript did not contain a similar analysis for the correlation of smoking and proximal aneurysms in younger patients, in whom the incidence of proximal AA was substantially higher than in older patients. Did the authors find any correlation between smoking and proximal aortic involvements in younger patients, and if not, how confident are they that this observation in older patients is real? Finally, it was interesting that younger patients more often had symptomatic aneurysms and that this could not be explained simply by larger size. Do the authors have an explanation for this observation? For example, did pathologic examination of aneurysmal tissue from younger patients reveal any evidence of an increased inflammatory component or other changes that might explain the frequent pain that these patients had in the absence of rupture? Alternatively, is it possible that asymptomatic aneurysms in younger patients are not detected because abdominal imaging studies are not performed as frequently for other diseases as in older patients? This study emphasizes that AA can occasionally de- velop in younger patients in whom their cause is no more clear than in older counterparts. The finding of more proximal aortic involvement in younger patients suggests a more diffuse connective dssue abnormality that may be a fruitful area of future investigation. Dr. Satish Muluk (Boston, Mass.). The first question related to whether AA disease in these young patients has a different cause or perhaps is related to the fact that the), have premature risk factors. It is certainly true that they have premature risk factors, although on the other hand, it',; also true that they had a different form of aneurysm disease by the various criteria that we use, including the complexity and size. So, it does appear to be a different entity. Despite the premature risk factor issue, we believe that it represents a different subset of aneurysmal disease. The disease was actually available in about 85% of these cases and did not reveal any significant differences in the disease between the two groups. This being a retrospective study, we were not specially looking for any difference in disease, and there is none reported, except in those cases where there was specific connected tissue or arteritis problems that were known about before operation in all the cases. Dr. Cronenwett brings up an interesting point about the issue of smoking decreasing in frequency with time in the general population. Although that's true, we were looking in the older patients with any prior smoking history and not necessarily whether they were smoking at the time of the assessment. The aneurysm complexity in the younger patient was quite striking. We do not have a good explanation for that except to say that there may be some genetic factors in conjunction with environmental factors, such as smoking, that may lead to this more diffuse and proximal involvement of the aorta. The issue of the higher symptom frequency among the young patients is an interesting phenomenon. Dr. Cronenwett suggests that it may be related to the fact that younger patients typically do not undergo screening for aneurysm disease; therefore it would only be recognized when the patients have symptoms. Nonetheless, taken with the fact that disease in younger patients is more proximal and that the aneurysms tended to be larger, it seems to fit in with a pattern of a more aggressive subtype of aneurysm disea,;e. Dr. Sateesh C. Babu (Valhalla, N.Y.). Did you have increased incidents of associated iliac aneurysms in these patients? How did you prevent or take precautions against sexual dysfunction; particularly because these are young patients? Do you have any protocol for monitoring them for future development of either thoracic aneurysms or distal aneurysms? Dr. Muluk. We did not find an increased incidence of lilac aneurysms. The incidence of iliac aneurysm was

9 888 Muluk et al. December 1994 marginally high among the older patients, suggesting that they had more distal involvement in the aorta. Those young patients who did have iliac involvement underwent nervesparing dissections, although that did not become an issue very often. The small number of patients did not lead to a well-defined protocol. However, most of these patients have been monitored by yearly CT scanning to look for further aneurysmal degeneration. Regarding the issue of whether smoking correlates with aneurysm complexity among the younger patients and the older patients, we studied these data, but, because such a high proportion of the younger patients were already smokers, the number of nonsmokers was too small to draw any meaningful correlation. Dr. Moshe I-Iaimov (New York, N.Y.). What is the age of the youngest patient with an aneurysm on whom you have operated? I had a patient who was 29 years old with renal artery stenosis, and this was a female patient who is now trying to get pregnant. How do you deal with pregnancy counseling on a patient of this nature? You told us that aneurysms in a young patient are aggressive lesions. Are your indications different in a patient with an aneurysm? Will yon operate on a 4 cm aneurysm in a patient who is younger compared with a 70 years old patient? Dr. Muluk. I believe that the youngest patient in our series was 29 years old. The issue of pregnancy did not come up. In terms of the indications for repair, we have not adopted any different indications for operating on these patients. Certainly if these aneurysms are detected, they would be monitored for increasing size. The standard indication of 5 to 6 cm would be used, and that varies depending on the extent of the aneurysm and whether the patient was having any symptoms. Obviously in the 50% or so of them admitted with symptoms, they underwent operation on an urgent basis. Dr. Michael F. Silane (New York, N.Y.). One finding that has raised some eyebrows is that smoking is associated with increased AAA complexity among older patients. I think that is absolutely true. We have been interested in the patterns of the disease, and by complexity I think the authors mean involvement of renal or suprarenal aorta. We have been looking at this particularly in women because we believe they have a higher incidence of the suprarenal component. The men often are obese but don't have severe lung disease, but in older women patients, when there is suprarenal involvement, they often have lungs that are debilitated and cachectic. Have you examined their siblings and if not, do you plan to? What would yon suggest in that regard? Dr. Muluk. The charts don't document family history very well, so the data were supplemented by calling many of the patients and their families. We were able to get a good family history by questioning patients directly. On the other hand, we did not undertake to examine relatives, which perhaps would add to the delineation of whether there really was a positive family history among those patients. Dr. Alan Graham (New Brunswick, N.J.). My question regards the long term follow-up of those patients. Do we have an idea about the mortality rate and the incidence of further aneurysm and coronary artery disease? Do the patients have aggressive coronary artery disease? Were they screened for this? Dr. Muluk. The patients typically have been monitored as outpatients for several years after their operation, and indeed the overall results seem to be very good. The long-term follow-up shows excellent survival rates. On the other hand there was no direct protocol for screening the patients for coronary artery disease, so we don't have data on that issue.