Risk factors for aneurysm rupture in patients kept under ultrasound surveillance. UK Small Aneurysm Trial Participants.
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OBJECTIVE: To investigate risk factors associated with aneurysm rupture using patients randomized into the U.K. Small Aneurysm Trial (n = 1090) or monitored for aneurysm growth in the associated study (n = 1167). SUMMARY BACKGROUND DATA: The U.K. Small Aneurysm Trial has shown that ultrasound surveillance is a safe management option for patients with small abdominal aortic aneurysms (4.0 to 5.5 cm in diameter), with an annual rupture rate of 1%. METHODS: In the cohort of 2257 patients (79% male), aged 59 to 77 years, 103 instances of abdominal aortic aneurysm rupture were identified during the 7-year period of follow-up (1991-1998). Almost all patients (98%) had initial aneurysm diameters in the range of 3 to 6 cm, and the majority of ruptures (76%) occurred in patients with aneurysms > or =5 cm in diameter. Kaplan-Meier survival and Cox regression analysis were used to identify baseline risk factors associated with aneurysm rupture. RESULTS: After 3 years, the annual rate of aneurysm rupture was 2.2% (95% confidence interval 1.7 to 2.8). The risk of rupture was independently and significantly associated with female sex (p < 0.001), larger initial aneurysm diameter (p < 0.001), lower FEV1 (p = 0.004), current smoking (p = 0.01), and higher mean blood pressure (p = 0.01). Age, body mass index, serum cholesterol concentration, and ankle/brachial pressure index were not associated with an increased risk of aneurysm rupture. CONCLUSIONS: Within this cohort of patients, women had a threefold higher risk of aneurysm rupture than men. Effective control of blood pressure and cessation of smoking are likely to diminish the risk of rupture. (+info)
Abdominal aortic aneurysm: a 6-year comparison of endovascular versus transabdominal repair.
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OBJECTIVE: To test the hypothesis that endovascular repair of abdominal aortic aneurysm (AAA) will result in a significant reduction in mortality and morbidity rates and cost when compared with open transabdominal repair. SUMMARY BACKGROUND DATA: Since the introduction of endovascular repair of AAA this decade, multiple groups have evaluated different endovascular grafts. Despite the excellent results reported initially, there has been a paucity of well-controlled, comparative studies looking at long-term outcome. METHODS: From 1992 to 1998, the first 100 consecutive patients undergoing endovascular AAA repair (mean age 74.7, AAA size 5.6 cm) were compared to 100 patients undergoing transabdominal repair (mean age 72.9, AAA size 5.9 cm). All patients undergoing endovascular repair received a device manufactured by Endovascular Technologies, Inc. (Menlo Park, CA) and were prospectively followed with periodic examination, contrast-enhanced computed tomography, and duplex scanning. Of the 200 patients, 198 have been available for long-term follow-up. RESULTS: The two groups had similar preoperative risk factors. Surgical time (211 vs. 256 minutes, p < 0.005), blood loss (326 vs. 1010 ml, p < 0.005), and blood replacement (0.4 vs. 1.6 units, p < 0.005) were all decreased in the endovascular group. Median intensive care unit stay (0 vs. 2 days) and hospital stay (2 vs. 7 days) were significantly reduced in the endovascular group. Insignificant trends in lower morbidity rates (myocardial infarction 1 % vs. 5%, respiratory failure 1 % vs. 5%, colon ischemia 0% vs. 2%) were present in patients undergoing endovascular repair. This led to decreased hospital cost and increased hospital profit. The surgical mortality rate (2% vs. 3%) and 5-year survival rate (65% vs. 72%) have been equivalent between the two groups. CONCLUSIONS: The surgical mortality rate is low for both groups and not statistically different. Endovascular repair significantly reduces resource utilization (surgical time, blood replacement, intensive care unit and hospital stay) and cost when compared to transabdominal aneurysm repair. Long-term survival is equivalent in patients undergoing AAA repair regardless of technique. Although endovascular repair appears durable for up to 6 years, longer follow-up studies are warranted. (+info)
The epidemiology of surgically repaired aneurysms in the United States.
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OBJECTIVE: The purpose of this study was to determine the results of surgery for hospitalized cases of aneurysms in the United States, thereby providing a standard of comparison for new techniques proposed to treat aneurysms. METHODS: Data on hospitalized aneurysm cases were collected from the National Hospital Discharge Survey, a comprehensive database of patients hospitalized in the United States for treatment from the years 1984 to 1994. The National Hospital Discharge Survey samples non-federal, acute-care hospitals with an average length of stay of less than 30 days. All the cases had a diagnosis of or a surgical procedure for a non-cerebral aneurysm. RESULTS: In the year 1994, 51,949 non-cerebral aneurysms were repaired in the United States, and 75% of these procedures were abdominal aortic aneurysm (AAA) surgeries. The operative mortality rates for AAA were higher than previously reported from multi-institutional studies and were found to be 8.4% for elective repair and 68% for emergency AAA repair. The number of aneurysm surgeries per thousand population varied by region: surgery rates were more frequent in the Northeast and less frequent in the West. Surgical volume appeared to decrease for smaller hospitals and increase for larger hospitals for the period between 1990 and 1994. The overall mortality rates for all aneurysm surgeries diminished with hospital size. However, no significant difference was found for the rates of elective AAA repair between hospital sizes. The percentage of men with aneurysms who underwent surgery for repair was significantly higher than for women with aneurysms. In addition, the AAA repair rates increased for men from 1985 to 1994, and the number of women reported with repaired AAAs remained constant. CONCLUSION: The location of aneurysm, urgency of repair, region, sex, and hospital size are important factors related to patient treatment and outcome. These data provide a standard of comparison against which surgeons can compare their own results, and they provide a benchmark for the evaluation of interventional techniques proposed to treat aneurysms. (+info)
Coagulation and fibrinolysis in patients undergoing operation for ruptured and nonruptured infrarenal abdominal aortic aneurysms.
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PURPOSE: Hemorrhage and thrombosis predisposing to myocardial infarction, multiple organ failure, and thromboembolism account for the majority of the morbidity and mortality associated with repair of ruptured and nonruptured abdominal aortic aneurysms (AAAs). The aim of this study was to examine coagulation and fibrinolysis in patients operated on for ruptured and nonruptured infrarenal AAAs. METHODS: Ten patients operated on for ruptured and 9 patients operated on for nonruptured AAAs were studied. Tissue plasminogen activator (t-PA) antigen, thrombin-antithrombin (TAT), and D-dimer were measured before induction of anesthesia. Plasminogen activator inhibitor (PAI) activity, t-PA activity, and prothrombin fragment (PF) 1+2 were measured before induction of anesthesia, immediately before aortic clamp release, and 5 minutes and 24 hours after aortic clamp release. RESULTS: Preoperatively, ruptured AAA was associated with significantly elevated t-PA antigen (median 15.7 ng/mL, range 9. 0 to 22.1 ng/mL versus nonrupture: median 6.6 ng/mL, range 4.7 to 16. 4 ng/mL; P <.01, Mann-Whitney test), increased PAI activity (median 36.5 arbitrary units/mL, range 20.6 to 38.8 arbitrary units/mL versus nonrupture: median 8.2 arbitrary units/mL, range 3.2 to 21.7 arbitrary units/mL; P <.001), reduced t-PA activity (median 0.12 IU/mL, range 0.06 to 0.4 IU/mL versus nonrupture: median 0.49 IU/mL, range 0.14 to 3.2 IU/mL; P <.01), elevated TAT (median 135.5 microg/L, range 61.2 to 209.4 microg/L versus nonrupture: median 21. 6 microg/L, range 6.6 to 180.4 microg/L; P <.02) and elevated PF 1+2 (median 9.0 nmol/L, range 5.4 to 11.6 nmol/L versus nonrupture: median 2.2 nmol/L, range 0.7 to 7.1 nmol/L, P <.001). There was no significant difference in preoperative D-dimer levels (median 3460 ng/mL, range 1236 to 7860 ng/mL versus nonrupture: median 1642 ng/mL, range 728 to 5334 ng/mL; P =.07). The differences in PAI activity, t-PA activity, and PF 1+2 persisted throughout the course of surgery, but there was no significant difference between the groups at 24 hours. CONCLUSION: These novel data demonstrate that ruptured AAA repair is associated with inhibition of systemic fibrinolysis and intense thrombin generation. Similar changes are seen in nonruptured AAA but are of a lesser magnitude. This procoagulant state may contribute to the microvascular and macrovascular thrombosis that leads to myocardial infarction, multiple organ failure, and thromboembolism. (+info)
Epidural anesthesia reduces length of hospitalization after endoluminal abdominal aortic aneurysm repair.
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PURPOSE: The low invasiveness of endoluminal abdominal aneurysm repair (EAAR) appears optimal for the use of epidural anesthesia (EA). However, reported series on EAAR show that general anesthesia (GA) is generally preferred. To evaluate the feasibility and problems encountered with EA for EAAR, patients undergoing EAAR with EA and patients undergoing EAAR with GA were examined. METHODS: From April 1997 through October 1998, EAAR was performed on 119 patients at the Unit of Vascular Surgery at Policlinico Monteluce in Perugia, Italy. Four patients (3%) required conversion to open repair and were excluded from the analysis because they were not suitable candidates for evaluating the feasibility of EA. The study cohort thus comprised 115 patients undergoing abdominal aortic aneurysm (AAA) repair with the AneuRx Medtronic stent graft. The incidence of risk factors and anatomical features of the aneurysm were compared in patients selected for EA or GA on the basis of intention-to-treat analysis. Intraoperative and perioperative data were compared and analyzed on the basis of intention-to-treat and on-treatment analysis. RESULTS: Sixty-one patients (54%) underwent the surgical procedure with EA (group A), and 54 (46%) underwent the surgical procedure with GA (group B). Conversion from EA to GA was required in four patients (3 of 61 patients, 5%). There were no statistically significant differences between the two study groups in demographics, clinical characteristics, and American Society of Anesthesiology classification (ASA). There was no perioperative mortality. Major morbidity occurred in 3% of patients (group B). According to intention-to-treat analysis, no significant differences were observed between the two groups in mean operating time, fluoro time, blood loss, amount of contrast media used, mean units of transfused blood, need of intensive care unit, mean postoperative hospital stay, and postoperative endoleak. Conversely, significant differences were found by means of on-treatment analysis in the need of intensive care unit (0 vs 5 patients; P =.02), and length of hospitalization (2.5 vs 3.2 days; P =.04). Multivariate logistic regression analysis showed that GA and ASA 4 were positive independent predictors of prolonged (more than 2 days) postoperative hospitalization (hazard ratio, 2.5; 95% CI, 1.1 to 5.8; P =.03, and hazard ratio, 5.1; 95% CI, 1.5 to 17.9; P =.007, respectively). CONCLUSION: EA for EAAR is feasible in a high percentage of patients in whom it is attempted, and it ensures a technical outcome comparable with that of patients undergoing EAAR with GA. Successful completion of EAAR with EA is associated with a short period of hospitalization. (+info)
Asymptomatic rupture of an aortoiliac aneurysm.
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The rupture of an abdominal aortic aneurysm is one of the most feared complications confronted by cardiovascular surgeons. Such ruptures are usually catastrophic, but in some instances the rupture is posterior and remains sealed. These chronic ruptures may manifest with any of a variety of clinical presentations. This report describes an uncommon presentation of a chronic rupture of an aortoiliac aneurysm in a patient with generalized aneurysmal disease. The rupture presented as an asymptomatic giant pulsatile mass in the patient's abdomen. The mass had developed over a period of several years. The literature is also reviewed. (+info)
Bacteroides fragilis bacteremia and infected aortic aneurysm presenting as fever of unknown origin: diagnostic delay without routine anaerobic blood cultures.
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We report the case of a 71-year-old male with Bacteroides fragilis bactermia and infected aortic aneurysm that went undiagnosed, in part, because routine anaerobic blood cultures were not obtained. Bacteremia caused by anaerobes has been reported to be declining, and recommendations to discontinue routine anaerobic blood cultures have been implemented in some hospitals. To our knowledge, this is the first report of an anaerobic bacteremia and infection that had a delay in diagnosis due to this change in blood-culturing protocol. The potential impact of deleting anaerobic blood cultures from routine protocols is discussed. (+info)
Cystatin C deficiency in human atherosclerosis and aortic aneurysms.
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The pathogenesis of atherosclerosis and abdominal aortic aneurysm involves breakdown of the elastic laminae. Elastolytic cysteine proteases, including cathepsins S and K, are overexpressed at sites of arterial elastin damage, but whether endogenous local inhibitors counterbalance these proteases is unknown. We show here that, whereas cystatin C is normally expressed in vascular wall smooth muscle cells (SMCs), this cysteine protease inhibitor is severely reduced in both atherosclerotic and aneurysmal aortic lesions. Furthermore, increased abdominal aortic diameter among 122 patients screened by ultrasonography correlated inversely with serum cystatin C levels. In vitro, cytokine-stimulated vascular SMCs secrete cathepsins, whose elastolytic activity could be blocked when cystatin C secretion was induced by treatment with TGF-beta(1). The findings highlight a potentially important role for imbalance between cysteine proteases and cystatin C in arterial wall remodeling and establish that cystatin C deficiency occurs in vascular disease. (+info)