Selective management of abdominal aortic aneurysms in a prospective measurement program

Purpose: The purpose of this study was to clarify the treatment of patients with small abdominal aortic aneurysms (AAAs) less than 5 cm in diameter and those believed to be unfit for operation with AAAs 5 cm diameter or greater.Methods: Four hundred ninety two patients with AAAs less than 5 cm when first seen were entered in a prospective measurement program by ultrasonography or computed tomography scan (exclusively after 1988) every 6 months. A decision regarding operative fitness was made when the AAA was 5 cm. Patients then underwent operation if fit or continued follow-up if their AAA was larger than 5 cm but they were unfit. A further group of 91 patients with aneurysms 5 cm or greater when first seen but unfit for repair were entered in the prospective measurement program.Results: In the group with AAAs less than 5 cm at entry, operation was performed in 201 patients as a result of increase in AAA size to 5 cm or greater (157), AAA expansion of more than 0.5 cm in 6 months (24), or for other reasons (20). Of those with AAAs smaller than 5 cm at entry, 291 have not undergone operation at a mean follow-up of 42 months. Expansion was significantly related to aneurysm size at entry and was highest in the 4.5 to 4.9 cm group at 0.7 cm/year. In the group of patients deemed unfit for operation with 5 cm AAAs [as a graduate of the less than 5 cm group at entry (85 patients) or first seen with AAA greater than 5 cm (91 patients)], 10 ruptures have occurred. Of these patients with ruptured AAAs, six had AAAs between 5.0 and 5.6 cm.Conclusions: Because of the risk of rupture demonstrated in our series in AAAs 5 cm or slightly greater and the progressive increase in expansion to a mean of 0.7 cm/year in those AAAs between 4.5 and 4.9 cm at entry, recommendation for elective operation in patients with AAAs between 4.5 and 5.0 cm should be strongly considered in a fit patient. (J VASC SURG1996;23:213-22.)     

The risk of rupture in untreated aneurysms: the impact of size,gender, and expansion rate

OBJECTIVE: The purpose of this study was to establish the risk of rupture as related to size of abdominal aortic aneurysm (AAA), gender, and expansion of the aneurysm. METHODS: Between 1976 and 2001, 476 patients with conditions considered unfit for surgery with AAA 5.0 cm or more were followed with computed tomographic scans every 6 months until rupture, surgery, death, or deletion from follow-up. Surgery was performed for rupture (n = 22), improved medical condition (n = 37), increase in size (n = 95), symptoms (n = 17), and other reasons (n = 24). RESULTS: Fifty ruptures occurred during the follow-up period. The average risk of rupture (and standard error) in male patients with 5.0-cm to 5.9-cm AAA was 1.0% (0.01%) per year, in female patients with 5.0-cm to 5.9-cm AAA was 3.9% (0.15%) per year, in male patients with 6.0-cm or greater AAA was 14.1% (0.18%) per year, and in female patients with 6.0-cm or greater AAA was 22.3% (0.95%) per year. CONCLUSION: The risk of rupture in male patients with AAA 5.0 to 5.9 cm is low. The four-time higher risk of rupture in female patients with AAA 5.0 to 5.9 cm suggests a lower threshold for surgery be considered in fit women. The data regarding risk of rupture in patients with AAA 6.0 cm or more may allow more appropriate decision analysis for surgery in patients with unfit conditions with large AAA.     

Expansion rates and outcomes for the 3.0-cm to the 3.9-cm infrarenal abdominal aortic aneurysm

OBJECTIVE: This study was performed for the determination of the expansion rates and outcomes and for recommendations for the surveillance of the 3.0-cm to 3.9-cm abdominal aortic aneurysm (AAA). DESIGN: The study was observational with data from patients screened with ultrasound scanning for AAA at five Veterans Affairs Medical Centers for enrollment in the Aneurysm Detection and Management Trial. The eligibility requirements included: AAA from 3.0 cm to 3.9 cm in diameter and at least one repeat ultrasound scan more than 90 days after the initial screening. Patients also completed a questionnaire for demographic data and the determination of the presence of risk factors associated with AAA. The study endpoints included: 1, both mean and median expansion rates; 2, moderate expansion (>4 mm/year); 3, no expansion; 4, all causes of death; 5, AAA rupture; 6, expansion to 4 cm or more; 7, expansion to 5.0 cm or more; and 8, operative repair. RESULTS: Ultrasound scan screening results identified 1445 patients with 3.0-cm to 3.9-cm AAAs. Seven hundred ninety men met the ultrasound scan criterion of having at least two ultrasound scan studies during the study period, and these 790 men were used for this study. Mean AAA size was 3.3 cm, with an average follow-up period of 3.89 +/- 1.93 years. The median expansion rate was 0.11 cm/year. Expansion rates were significantly different (P <.001) between 3.0-cm and 3.4-cm cm AAA and 3.5-cm and 3.9-cm AAA. There were no reported AAA ruptures during the study period, although cause of death data were available in only 43% of the patients. Few 3.0-cm to 3.9-cm AAAs expanded to 5.0 cm or more during the study period. The patients with 3.0-cm to 3.9-cm AAAs who underwent operative repair during the study period were younger, had larger initial AAA diameters, and had more rapid expansion rates. CONCLUSION: AAAs of 3.0 cm to 3.9 cm expanded slowly, did not rupture, and rarely had operative repair or expanded to more than 5.0 cm in our study of male patients. Expansion rates and the incidence rate of operative repair are more common in the 3.5-cm to 3.9-cm AAA when compared with the 3.0-cm to 3.4-cm AAA.     

Should abdominal aortic aneurysm be managed differently in women?

Although abdominal aortic aneurysm (AAA) is 4 to 6 times more common in men than in women, more than a third of all AAA deaths occur in women. In several reports from the UK Small Aneurysm Trial group, the rupture rate for women was 3-4 times that seen in men. A joint council of several vascular societies responded to these observations with the recommendation that AAA should be repaired earlier in women, at 4.5 cm to 5.0 cm rather than the 5.5 cm established in randomized trials for men. However, this recommendation does not appear to reflect a full consideration of the evidence. For example, population-based studies have reported mortality following AAA repair to be 40-60% higher in women than in men. Also, in the UK Small Aneurysm Trial itself, there was no trend toward a benefit from early repair in women. The totality of evidence available at present provides no good reason to alter for women the 5.5 cm threshold for elective repair established for men by the small AAA trials.     

The natural history of abdominal aortic aneurysms

This study examines the rate of expansion of abdominal aortic aneurysms and the risk of rupture in relation to their size. To assess these variables, we conducted a prospective study of 300 consecutive patients who presented over a 6-year interval with abdominal aortic aneurysms (AAA) that were initially managed nonoperatively. The mean age of the patients was 70.4 years, and 211 (70%) were men. The mean initial aneurysm diameter was 4.1 cm. Among the 208 patients who underwent more than one ultrasound or computed tomographic (CT) scan, the diameter of the aneurysm increased by a median of 0.3 cm per year. The 6-year cumulative incidence of rupture was 1% and 2% among patients with aneurysms less than 4.0 cm and 4.0 to 4.9 cm in diameter, respectively (p greater than 0.05). In comparison, the 6-year cumulative incidence of rupture was 20% among patients with aneurysms greater than 5.0 cm in diameter (p less than 0.004). We conclude that (1) abdominal aortic aneurysms expand at a median rate of 0.3 cm per year; and (2) the risk of rupture of abdominal aortic aneurysms less than 5.0 cm is substantially lower than the risk of rupture of aneurysms 5.0 cm or more in diameter.     

Growth rate and associated factors in small abdominal aortic aneurysms.

OBJECTIVE: To study the growth rate and factors influencing progression of small infrarenal abdominal aortic aneurysms (AAA). DESIGN: Observational, longitudinal, prospective study. PATIENTS AND METHODS: We followed patients with AAA <5 cm in diameter in two groups. Group I (AAA 3-3.9 cm, n = 246) underwent annual ultrasound scans. Group II (AAA 4-4.9 cm, n = 106) underwent 6-monthly CT scans. RESULTS: We included 352 patients (333 men and 19 women) followed for a mean of 55.2+/-37.4 months (6.3-199.8). The mean growth rate was significantly greater in group II (4.72+/-5.93 vs. 2.07+/-3.23 mm/year; p<0.0001). Group II had a greater percentage of patients with rapid aneurysm expansion (>4 mm/year) (36.8 vs. 13.8%; p<0.0001). The classical cardiovascular risk factors did not influence the AAA growth rate in group I. Chronic limb ischemia was associated with slower expansion (< or = 4 mm/year) (OR 0.47; CI 95% 0.22-0.99; p = 0.045). Diabetic patients in group II had a significantly smaller mean AAA growth rate than non-diabetics (1.69+/-3.51 vs. 5.22+/-6.11 mm/year; p = 0.032). CONCLUSIONS: The expansion rate of small AAA increases with the AAA size. AAA with a diameter of 3-3.9 cm expand slowly, and they are very unlikely to require surgical repair in 5 years. Many 4-4.9 cm AAA can be expected to reach a surgical size in the first 2 years of follow-up. Chronic limb ischemia and diabetes are associated with reduced aneurysm growth rates.     

Palliation of Abdominal Aortic Aneurysms in the Endovascular Era

ObjectivesTo establish outcome of patients with abdominal aortic aneurysm (AAA) deemed unfit for repair.DesignRetrospective non-randomised study.Materials and methodsIdentification of males with >5.5 cm or females with >5.0 cm AAA turned down for elective repair between 01/01/2006–24/07/2009 from a prospective database. Comorbidities, reasons for non-intervention, aneurysm size, survival, use of CPEX (cardio-pulmonary exercise) testing and cause of death were analysed. Although well-established at the time, patients unfit for open operation were not considered for endovascular repair.ResultsSeventy two patients were unsuitable for AAA repair. Aneurysm size ranged from 5.3 cm to 12 cm. Functional status, comorbidity and patient preference determined decision to palliate. Sixty percent of patients were alive at study close. Aneurysm rupture was cause of death in 46%. CPEX testing was performed in 54%, whose mortality was 28%, vs. 54% in the non-CPEX group (P < 0.05).Median survival of patients with 5.1–6.0 cm AAA was 44 months and 11% died of rupture. Between 6.1 and 7.0 cm median survival was 26 months and 20% died of rupture. However, with >7 cm aneurysms, survival was 6 months and 43% ruptured.ConclusionUnder half the deaths in our comorbid cohort were due to rupture. However, decision to palliate may be revisited as risk-benefit ratio changes with aneurysm expansion.     

Variables that affect the expansion rate and outcome of small abdominal aortic aneurysms

Seventy-three patients with small (less than 6 cm in diameter) abdominal aortic aneurysms (AAAs) were selected for nonoperative management and followed up with sequential ultrasound size measurements. Fifty-four men and 19 women, 51 to 89 years of age (mean 70 years), had an initial mean AAA size of 4.1 cm (anteroposterior) x 4.3 cm (lateral) diameter, with a calculated elliptic cross-sectional area of 14.3 cm2. After a mean of 37 months of follow-up, AAA area increased at a mean rate of 20% per year (3 cm2 yr; 0.4 to 0.5 cm/yr diameter). Expansion rate was not affected by initial aneurysm size. During follow-up, only 3 patients (4%) required urgent operation (1 died), 26 patients (36%) died of non-AAA causes, and 26 patients (36%) underwent elective AAA repair because of progressive size increase (1 died). Elective operations were performed at the rate of 10% per year, when mean AAA size had increased to 22 cm2 (5.1 cm in diameter). Multiple regression analysis of clinical parameters available at presentation indicated that subsequent elective AAA repair was predicted by younger age at diagnosis and larger initial aneurysm size. As anticipated, patients who underwent surgery had more rapid aneurysm expansion (5.3 cm2/yr) compared with patients who did not undergo surgery (1.6 cm2/yr; p less than 0.05). This difference was caused by more rapid expansion during later follow-up intervals among patients selected for operation and was not predicted by the change in aneurysm size observed during initial ultrasonographic follow-up. Final aneurysm size was predicted by initial size, duration of follow-up, and both systolic and diastolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Screening of abdominal aortic aneurysm: a pragmatic approach

In order to evaluate the feasibility of a selective screening programme for abdominal aortic aneurysm (AAA) within an urban setting and assess its impact on the expected increase in workload for the local hospital(s), a population based, prospective study was performed. A total of 4823 men aged 65 years were invited for ultrasound examination of the abdominal aorta between January 1993 and April 1997 as part of a general practice-based aneurysm screening programme covering two districts with a general hospital each. All examinations were carried out by senior radiographers using a portable B mode grey scale machine and a 3.5 MHz curvi-linear array probe. Patients with a maximum aortic diameter of over 3 cm were annually recalled, those with over 4 cm were referred to hospital for an out-patient's appointment. Those with AAA greater than 5 cm were considered for surgery. Of those approached, 3497 (72.5%) took part in the study, 1206 (25%) did not attend and 120 (2.5%) were excluded by their general practitioners (GPs) on medical grounds. Of the men taking part, 3130 (89.5%) had an aortic diameter equal to or less than 2.5 cm, 196 (5.6%) between 2.6 and 3.0 cm, and 171 (4.9%) had aortic diameters greater than 3 cm--29 of whom had AAA greater than 5 cm with a mean diameter of 6.0 cm (range 5.1-9.0 cm). Of 127 men with an initial diameter of 3.1-4.0 cm (mean progression in size of 2.3 mm/year), 22 enlarged to > 4 cm and 3 to > 5 cm. Of 24 men with an initial diameter of 4.1-5.0 cm, 6 enlarged to > 5 cm. Some 69 (2%) patients were referred to hospital requiring a total of 125 consultations (1.8 consultations per patient); 21 underwent surgery and one died from rupture whilst awaiting surgery. Five patients refused their operation and two failed to attend the clinic (all > 5 cm) but remain well to date. No patient died following surgery. We conclude that, screening for AAA in men at age 65 years within an urban setting is feasible and well received by patients and GPs. Screening does not lead to a huge increase in terms of outpatient appointments and operations for AAA.     

Aneurysm enlargement following endovascular aneurysm repair: AneuRx clinical trial

OBJECTIVE: The purpose of this study was to determine the incidence and significance of aneurysm enlargement, with or without treatment, in relation to the primary end points of rupture, surgical conversion, aneurysm-related death, and survival following endovascular repair. METHOD: Aneurysm (AAA) size changes and clinical outcome of all patients treated from 1997 through 1998 during the Phase II AneuRx multicenter clinical trial of endovascular AAA repair were reviewed. Aneurysm dimensions and the presence or absence of endoleak were determined by an independent core laboratory, with enlargement or shrinkage defined as a diameter change of 5 mm or more compared with baseline. RESULTS: Among 383 patients (89% men, 11% women, age 73 +/- 9 years), with a mean device implant time of 36 +/- 11 months (median = 39 months), aneurysm diameter decreased from 5.7 +/- 1.0 at baseline to 5.2 +/- 1.0 at 3 years (P =.0001). A total of 46 patients (12%) experienced AAA enlargement, 199 patients (52%) had no change in AAA diameter, and 138 patients (36%) had a decrease in AAA diameter of 5 mm or more. Significant risk factors for enlargement included age (enlargement patients were 4 years older on average than patients with aneurysms that decreased in size; P =.002) and the presence of an endoleak (P <.001). Among patients with endoleak at any time, 17% had aneurysm enlargement, whereas only 2% of patients without endoleak had aneurysm enlargement (P <.001). Patients with enlargement were more likely to undergo secondary endovascular procedures and surgical conversions (P <.001). Twenty patients (43%) with enlargement underwent treatment, and 26 patients were untreated. There were two deaths following elective surgical conversion and one death in a patient with untreated enlargement and a type I endoleak. Three aneurysms ruptured: one with enlargement, one with no change, and one with a decrease in aneurysm size; all three aneurysms were larger than 6.5 cm. Kaplan-Meier analysis showed that freedom from rupture at 3 years was 98% with enlargement, 99% with no change, and 99% with decrease in AAA size (log-rank test, not significant). Freedom from AAA death at 3 years was 93% in patients with enlargement, 99% in no increase, and 99% in decrease (P =.005). Survival at 3 years was 86% with increase, 82% with no change, and 93% with decrease (P =.02). CONCLUSIONS: Aneurysm enlargement following endovascular repair was not associated with an increased risk of aneurysm rupture or decrease in patient survival during a 3-year observation period. Aneurysm size rather than enlargement may be a more meaningful predictor of rupture. Close follow-up and a high re-intervention rate (43%) may account for the low risk of rupture in patients with enlargement. The long-term significance of aneurysm enlargement following endovascular repair remains to be determined.     

Endovascular repair or surveillance of patients with small AAA.

OBJECTIVE: To compare the outcome of patients with small abdominal aortic aneurysms (AAA) treated in a prospective trial of endovascular aneurysm repair (EVAR) to patients randomized to the surveillance arm of the UK Small Aneurysm Trial. METHOD: All patients with small AAA (< or = 5.5 cm diameter) treated with a stent graft (EVARsmall) in the multicenter AneuRx clinical trial from 1997 to 1999 were reviewed with follow up through 2003. A subgroup of patients (EVARmatch) who met the age (60-76 years) and aneurysm size (4.0-5.5 cm diameter) inclusion criteria of the UK Small Aneurysm Trial were compared to the published results of the surveillance patient cohort (UKsurveil) of the UK Small Aneurysm Trial (NEJM 346:1445, 2002). Endpoints of comparison were aneurysm rupture, fatal aneurysm rupture, operative mortality, aneurysm related death and overall mortality. The total patient years of follow-up for EVAR patients was 1369 years and for UK patients was 3048 years. Statistical comparisons of EVARmatch and UKsurveil patients were made for rates per 100 patient years of follow up (/100 years) to adjust for differences in follow-up time. RESULTS: The EVARsmall group of 478 patients comprised 40% of the total number of patients treated during the course of the AneuRx clinical trial. The EVARmatch group of 312 patients excluded 151 patients for age < 60 or > 76 years and 15 patients for AAA diameter < 4 cm. With the exception of age, there were no significant differences between EVARsmall and EVARmatch in pre-operative factors or post-operative outcomes. In comparison to the UKsurveil group of 527 patients, the EVARmatch group was slightly older (70 +/- 4 vs. 69 +/- 4 years, p = 0.009), had larger aneurysms (5.0 +/- 0.3 vs. 4.6 +/- 0.4 cm, p < 0.001), fewer women (7 vs. 18%, p < 0.001), and had a higher prevalence of diabetes and hypertension and a lower prevalence of smoking at baseline. Ruptures occurred in 1.6% of EVARmatch patients and 5.1% of UKsurveil patients; this difference was not significant when adjusted for the difference in length of follow up. Fatal aneurysm rupture rate, adjusted for follow up time, was four times higher in UKsurveil (0.8/100 patient years) than in EVARmatch (0.2/100 patient years, p < 0.001); this difference remained significant when adjusted for difference in gender mix. Elective operative mortality rate was significantly lower in EVARmatch (1.9%) than in UKsurveil (5.9%, p < 0.01). Aneurysm-related death rate was two times higher in UKsurveil (1.6/100 patient years) than in EVARmatch (0.8/100 patient years, p = 0.03). All-cause mortality rate was significantly higher in UKsurveil (8.3/100 patient years) than in EVARmatch (6.4/100 patient years, p = 0.02). CONCLUSIONS: It appears that endovascular repair of small abdominal aortic aneurysms (4.0-5.5 cm) significantly reduces the risk of fatal aneurysm rupture and aneurysm-related death and improves overall patient survival compared to an ultrasound surveillance strategy with selective open surgical repair.     

Abdominal aortic aneurysms: screening,epidemiology and open surgical repair

Abdominal Aortic Aneurysm (AAA) is a dilatation of the infra-renal abdominal aorta to greater than 3 cm. Population screening is offered to men in their 65th year in the UK. Patients with small AAAs (<5.5 cm) are entered into surveillance programs and should have cardiovascular risk factors managed aggressively. An AAA with ≥5.5 cm diameter should be considered for surgical repair to prevent rupture. Open surgical repair has proven to be a durable treatment for AAA and while less often performed than endovascular aneurysm repair (EVAR) it remains a common approach in the surgical management of AAA. While associated with higher short-term risks than EVAR, the long-term outcomes are similar and many younger patients have a preference for open repair as routine follow-up is not required.     

Prognosis of patients turned down for conventional abdominal aortic aneurysm repair in the endovascular and sonographic era: Szilagyi revisited?

PURPOSE: The United Kingdom Small Aneurysm study has demonstrated the low risk of rupture in aneurysms less than 5.5 cm in diameter. With the advent of endoluminal techniques, patients considered unfit to undergo laparotomy are now considered for endovascular repair. However, the natural history of aneurysms larger than 5.5 cm remains uncertain, especially when severe comorbidity is present. In our center, we prospectively maintain records of all patients for whom elective aneurysm surgery was refused. This study documented the outcome of all patients referred with abdominal aortic aneurysms (AAAs) larger than 5.5 cm in diameter who were turned down for elective open repair and determined the cause of death and risk of rupture in all patients. METHODS: Details of all patients with AAAs from January 5, 1989, to January 5, 1999, were recorded, and demographic details on all patients with AAAs larger than 5.5 cm were collected. Copies of death certificates were obtained from the Office of National Statistics, local in-hospital patient records, and general practitioner records. Results of postmortem examinations were also obtained. Aneurysms were stratified according to their size at presentation (5.5-5.9 cm, 6.0-7.0 cm, and > 7.0 cm), and the reasons no intervention was made were documented. RESULTS: A total of 106 patients were turned down for elective aneurysm surgery in the 10-year period (10.6 per year). The mean age of the patients was 78.4 years (SD, 7.4), and 70 were men and 36 were women. At the end of the study, 76 patients (71.7%) had died. Overall, the 3-year survival rate was 17%. Patients with AAAs larger than 7.0 cm lived a median of 9 months. A ruptured aneurysm was certified as a cause of death in 36% of the patients with an AAA of 5.5 to 5.9 cm, in 50% of the patients with an AAA of 6 to 7.0 cm, and 55% of the patients with an AAA larger than 7.0 cm. Reasons given for not intervening were patient refusal (31 cases), the patient being "unfit for surgery" (18 cases), the "advanced age" of the patient (18 cases), cardiac disease (9 cases), cancer (9 cases), respiratory disease (6 cases), and other (15 cases). CONCLUSION: Although we recognize the problems with death certification, we found that rupture was a significant cause of death in patients with an untreated AAA that was larger than 5.5 cm. Although little difference in outcome was observed in aneurysms in the 5.5 to 7.0 cm size range, patients with an AAA that was larger than 7.0 cm seemed to have a much poorer prognosis.     

Repair of large abdominal aortic aneurysm should be performed early after coronary artery bypass surgery

PURPOSE: The surgical repair (coronary artery bypass grafting [CABG]) of symptomatic coronary artery disease (CAD) in patients with co-existent large abdominal aortic aneurysm (AAA) may result in an increased rate of AAA rupture after operation. Simultaneous CABG/AAA repair has been recommended by some surgeons, but with a somewhat higher mortality rate than staged repair. We reviewed the outcome of staged AAA repair that was performed early after CABG in patients with symptomatic coronary disease and AAA. METHODS: The records of all the patients with symptomatic CAD that required CABG with large AAA (greater than 5 cm) were reviewed. In most patients, CABG was performed first, followed by AAA repair within 2 weeks. Patient demographics, severity of coronary disease, AAA size, interprocedure duration, and perioperative morbidity and mortality rates were examined. RESULTS: Between 1991 and 1998, 1105 AAA repairs were performed. Within this group, 30 patients with AAA underwent CABG for symptomatic CAD. Mean AAA size was 6.6 cm (range, 5.0-10.0 cm). The median interprocedure interval between CABG and AAA repair was 11.5 days. There was no in-hospital AAA rupture during this interval. The patient group was comprised of 24 men and 6 women with a mean age of 71 years. There was no operative death after such staged AAA repair, and nonfatal complications occurred in seven patients (23%). During this period, seven patients had AAA rupture when they were sent home after CABG for recovery and intended AAA repair at a later date. CONCLUSION: Staged elective AAA repair may be performed safely and effectively after CABG. Performance of these procedures with a short interprocedure interval may be preferable to the higher complication rate observed after combined procedures.     

Natural history of patients with abdominal aortic aneurysm

Factors determining the outcome for patients with abdominal aortic aneurysm (AAA) were analysed in a retrospective population-based study of 187 consecutively diagnosed AAAs at one hospital during a 9-year period. All aneurysms were diagnosed by ultrasound, and those cases that were not primarily operated upon, were followed by repeat ultrasound examinations. An expansion rate of more than 0.4 cm/year was seen in 27% of the aneurysms and a tendency towards a higher rate of expansion could be seen with larger lesions. The overall cumulative rupture rate was 12% at 5 years. For patients with small (less than 5 cm) aneurysms it was 2.5% at 7 years, and no aneurysm could definitively be shown to be smaller than 5 cm at the time of rupture. The rupture risk was significantly higher (28% at 3 years) for larger aneurysms (greater than or equal to 5 cm). The only reliable predictor for rupture was aneurysm size. The overall cumulative survival was 51% at 5 years. Patients with large aneurysms did not have a significantly shorter survival although a tendency for this to be the case was found. There was a significant difference between the proportion of deaths caused by aneurysm rupture in patients with small aneurysms when compared to those with large aneurysms, 5.5 and 53%, respectively. The expansion rate for AAA was highly individual and aneurysm diameter was the only recognisable predictor of rupture. The rupture rate for AAAs smaller than 5 cm was lower than previously reported.     

The rupture rate of large abdominal aortic aneurysms: is this modified by anatomical suitability for endovascular repair?

BACKGROUND: There are no precise estimates of the rate of rupture of large abdominal aortic aneurysms (AAA). There is recent suspicion that anatomic suitability for endovascular repair may be associated with a decreased risk of AAA rupture. METHODS: Systematic literature review of rupture rates of AAA with initial diameter > or =5 cm in patients not considered for open repair, with stratification by size (<6.0 cm and 6.0+ cm), and gender, combined using random-effects meta-analysis. Proportional hazards regression to analyze factors (including gender, diabetes, initial AAA diameter, aneurysm neck, and sac lengths) associated with rupture in patients anatomically suitable for endovascular repair (EVAR 2 trial). RESULTS: Previous studies (2 prospective, 2 retrospective, and 1 mixed) were identified for meta-analysis and patients with elective repair excluded. The pooled rupture rates was 18.2 [95% confidence interval (CI) 13.7-24.1] per 100 person-years. There was a 2.5-fold increase in rupture rates for patients with AAA of 6.0+ cm versus <6.0 cm, rupture rates = 2.54 (95% CI 1.69-3.85). The pooled rupture rates was nonsignificantly higher in women than men, rupture rates = 1.21 (95% CI 0.77-1.90). For EVAR 2 patients with 6+ cm aneurysms the rupture rates was 17.4 [95% CI 12.9-23.4] per 100 person-years significantly lower than the pooled rate from the meta-analysis, rupture rates = 27.0 [95% CI 21.1-34.7] per 100 person-years, P = 0.026. Patients with shorter neck lengths appeared to have a higher rupture rates than those with longer necks, but this was of borderline significance P = 0.10. CONCLUSIONS: Rupture rates of large AAAs reported in different studies are highly variable. There is emerging evidence that patients anatomically suitable for endovascular repair have lower rupture rates.     

Abdominal aortic aneurysm in the interval 5.0-5.5 cm, art or evidence?

The risk of rupture for aneurysms 5-5.5 cm in diameter has not been specifically studied. Two large randomised trials, the United Kingdom Small Aneurysm Trial and the Aneurysm Detection And Management Study Trial concluded that immediate surgical repair did not offer any benefit compared to surveillance and surgical repair if the aneurysm reached 5.5 cm or became symptomatic. Despite these findings many indications today suggest that a lower threshold should be used in patients with higher risk for rupture e.g. women or low risk of mortality in connection with AAA repair such as patients in the lower range of ages.     

Cost-effectiveness of screening women for abdominal aortic aneurysm

BACKGROUND: Women are usually not considered for abdominal aortic aneurysm (AAA) screening because of their lower prevalence of disease. This position may, however, be questioned given the higher risk of rupture and the longer life expectancy among women. The purpose of this study was to assess the cost-effectiveness of screening 65-year-old women for AAA. METHODS: A systematic review of the literature was conducted to obtain data of importance to evaluate the effectiveness of screening women for AAA. Data were entered into a Markov simulation cohort model. RESULTS: The review suggested some main assumptions for women with AAA. Prevalence is 1.1%. In 6.8%, the AAA is of a size that merits surgery, and the patients are fit for a procedure. For patients with an AAA, the yearly risk for elective surgery and the rupture incidence was 3.1% and 2.4%, respectively, in the invited group and 1.1% and 5.7% in the noninvited group. The operative mortality for elective surgery was 3.5%, and the total mortality for ruptured AAA was 86.3%. The long-term mortality for AAA patients was 3.6 times higher than for an age-matched healthy population. Screening reduced the AAA rupture incidence by 33% and the AAA-related death rate by 35%. The cost per life year gained was estimated at $5911. CONCLUSION: The incremental cost-effectiveness ratio was similar to that found for screening men, which reflects the fact that the lower AAA prevalence in women is balanced by a higher rupture rate. Screening women for AAA may be cost-effective, and future evaluations on screening for AAA should include women.     

The cost-effectiveness of early surgery versus watchful waiting in the management of small abdominal aortic aneurysms

Purpose: The purpose of this study was to compare the relative cost-effectiveness of two clinical strategies for managing 4 to 5 cm diameter abdominal aortic aneurysms (AAAs): early surgery (repair 4 cm AAA when diagnosed) versus watchful waiting (monitor AAA with ultrasound size measurements every 6 months and repair if the diameter reaches 5 cm).Methods: We used a Markov decision tree to compute the expected survival in quality-adjusted life years (QALYs) for each strategy, based on literature-derived estimates for the probabilities of different outcomes in this model. We determined hospital costs for patients undergoing elective and emergency AAA repair at our center. With standard methods of cost accounting, we then calculated the additional cost per year of life saved by early surgery compared with watchful waiting (cost-effectiveness ratio, dollars/QALY).Results: Mean hospital costs for elective and emergency AAA repair were $24,020 and $43,208, respectively (1992 dollars). For our base-case analysis (60-year-old men with 4 cm diameter AAAs, with 5% elective operative mortality rate and 3.3% annual rupture rate), early surgery improved survival by 0.34 QALYs compared with watchful waiting, at an incremental cost of $17,404/QALY. Increased elective surgical mortality rate, decreased AAA rupture risk, and increased patient age all reduced the cost-effectiveness of early surgery. Future increases in elective operative risk, noncompliance with ultrasound follow-up and increased threshold size for elective AAA repair during watchful waiting all improved the cost-effectiveness of early surgery. Future increases in elective operative risk, noncompliance with ultrasound follow-up and increased threshold size for elective AAA repair during watchful waiting all improved the cost-effectiveness of early surgery.Conclusions: The cost effectiveness of early surgery for 4 cm diameter AAAs in carefully selected patients compares favorably with that of other commonly accepted preventive interventions such as hypertension screening and treatment. With an upper limit of $40,000/QALY as an "acceptable" cost-effectiveness ratio, early surgery appears to be justified for patients 70 years old or younger, if the AAA rupture risk is 3%/year or more and the elective operative mortality rate is 5% or less. Although not a substitute for clinical judgment, this cost-effectiveness analysis delineates the essential tradeoffs and uncertainties in treating patients with small AAAs. (J VASC SURG 1994;19:980–91.)     

Analysis of expansion patterns in 4-4.9 cm abdominal aortic aneurysms

Our objective was to analyze the growth pattern of 4-4.9 cm infrarenal abdominal aortic aneurysms (AAAs). We used an observational, longitudinal, prospective study design. We followed 4-4.9 cm AAAs with 6-monthly abdominal computed tomographic (CT) scans (January 1988-August 2004). AAA growth was defined as an increase in aortic diameter > or =2 mm in each surveillance period. We established the aortic expansion pattern in AAA with three or more CT scans as continuous, discontinuous. The latter includes at least one period of nongrowth (<2 mm/6 months). We studied the influence of cardiovascular risk factors (CVRFs), comorbidity, and AAA anatomical characteristics using the chi-squared test, t-test, life tables, and Kaplan-Meier for statistical analysis. We included 195 patients: 183 (93.8%) men, age 71 +/- 8.3 years (50-90). The follow-up period was 50 +/- 36.4 months (6.5-193.7). The growth pattern (n =131) was continuous in 15 (11.5%) and discontinuous in 116 (88.5%) AAA. The mean expansion rate was higher in AAAs with continuous expansion (7.92 +/- 3.74 vs. 2.74 +/- 2.94 mm/year, p < 0.0001). No CVRFs or comorbidity influenced the expansion pattern (p > 0.05). The eccentric thrombus was associated with a greater incidence of continuous growth (p = 0.05), with no influence of aortic calcification (p > 0.1). The expansion of 4-4.9 cm AAA is mostly irregular and unpredictable. We have not found any modifiable risk factors which influence their growth pattern. The eccentric distribution of the thrombus is associated with continuous expansion.