Cost-effectiveness of surgery for small abdominal aortic aneurysms on the basis of data from the United Kingdom small aneurysm trial

PURPOSE: Although the United Kingdom small aneurysm trial reported no survival benefit for early operation in patients with small (4. 0-5.5 cm) abdominal aortic aneurysms (AAAs), the trial lacked statistical power to detect small but potentially meaningful gains in life expectancy, particularly for specific subgroups. We used decision analysis to better characterize the potential benefits and cost-effectiveness of early surgery. METHODS: We used a Markov model to assess the marginal cost-effectiveness (incremental cost per quality-adjusted life year [QALY] saved) of early surgery relative to surveillance for small AAAs, using data from the UK Trial. Subgroup analyses were performed by patient age and AAA diameter. Sensitivity analysis was used to evaluate the effect of elective operative mortality on cost-effectiveness. RESULTS: In our baseline analysis, early operations provided a small survival advantage (0.14 QALYs) at a small incremental cost of $1510. Thus, despite a small survival benefit, early surgery appeared cost-effective ($10, 800/QALY). The small cost differential resulted from the large proportion of patients who underwent surveillance, who eventually underwent AAA repair, and therefore incurred the cost of the surgical procedures. The survival advantage and cost-effectiveness of early operation increased with lower operative mortality, younger age, and larger AAA diameter. CONCLUSION: Despite the negative conclusions of the UK trial, early surgery may be cost-effective for patients with small AAAs, particularly younger patients (<72 years of age) with larger AAAs (> or = 4.5 cm). Because the gains in life expectancy are relatively small, however, clinical decision making should be strongly guided by patient preferences.     

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.)     

The cost-effectiveness of endovascular repair versus open surgical repair of abdominal aortic aneurysms: A decision analysis model

PURPOSE: Endovascular repair (EVR) is a less-invasive method for the treatment of abdominal aortic aneurysms (AAAs) as compared with open surgical repair (OSR). The potential benefits of EVR include increased patient acceptance, less resource utilization, and cost savings. This study was designed to determine whether the EVR of AAAs is a cost-effective alternative to OSR. METHODS: A cost-effectiveness analysis was performed using a Markov decision analysis model to compute long-term survival rates in quality-adjusted life years and lifetime costs for a hypothetical cohort of patients who underwent either OSR or EVR. Probability estimates of the different outcomes of the two alternative strategies were made on the basis of a review of the literature. The average costs of (1) the immediate hospitalization ($16,016 for OSR, $20,083 for EVR), (2) the complications that resulted from each procedure, (3) the subsequent interventions, and (4) the surveillance protocol were determined on the basis of average resource utilization as reported in the literature and from our hospital's cost accounting system. Our measure of outcome was the cost-effectiveness ratio. RESULTS: For our base-case analysis (70-year-old men with 5-cm AAAs), EVR was cost-effective with a cost-effectiveness ratio of $22,826-society usually is willing to pay for interventions with cost-effectiveness ratios of less than $60,000 (eg, cost-effectiveness ratios for coronary artery bypass grafting and dialysis are $9500 and $54,400, respectively). This conclusion did not vary significantly with increases in procedural costs for EVR (ie, if the cost of the endograft increased from $8000 to $12,000, EVR remained cost-effective with a cost-effectiveness ratio of $32,881). The cost-effectiveness of EVR was critically dependent on EVR producing a large reduction in the combined mortality and long-term morbidity rate (stroke, dialysis-dependent renal failure, major amputation, myocardial infarction) as compared with OSR (ie, a reduction in the combined mortality and long-term morbidity rate of OSR from 9.1% to 4.7% made EVR no longer cost-effective). CONCLUSION: Despite the high cost of new technology and the need for close postoperative surveillance, EVR is a cost-effective alternative for the repair of AAAs. However, the cost-effectiveness of this new technology is critically dependent on its potential to reduce morbidity and mortality rates as compared with OSR. EVR may not be cost-effective in medical centers where OSR can be performed with low risk.     

A cost analysis of surgery for ruptured abdominal aortic aneurysm.

OBJECTIVE: This study compares our costs of salvaging patients with ruptured abdominal aortic aneurysms (AAA) with the costs for unruptured AAAs. METHODS: Details of all AAAs presenting over 18 months were obtained. Costs of repair were carefully calculated for each case and were based upon ITU and ward stay and the use of theatre, radiology and pathology services. We compared the costs in unruptured AAAs with both uncomplicated ruptures and ruptures with one or more system failure. RESULTS: The mortality rate for ruptures undergoing repair was 18% and for elective repairs was 1.6%. The median cost for uncomplicated ruptures was 6427 Pounds (range 2012-13,756 Pounds). For 12 complicated ruptures, it was 20,075 Pounds (range 13,864-166,446 Pounds), and for 63 unruptured AAAs, was 4762 Pounds (range 2925-47,499 Pounds). CONCLUSION: Relatively low operative mortality rates for ruptured AAA repair can be achieved but this comes at substantial cost. On average, a ruptured AAA requiring system support costs four times as much as an elective repair.     

Epidemiology and Outcome of Aortic Aneurysms in Hong Kong

Abstract The objective of this study was to determine epidemiology and mortality statistics for abdominal aortic aneurysms (AAAs) in Hong Kong. Data from three sources were obtained and analyzed: (1) Hong Kong Hospital Authority discharge statistics for 1999 and 2000; (2) a survey on aortic aneurysms in public hospitals conducted by the Working Group of Vascular Surgery; and (3) the Department of Surgery, University of Hong Kong Medical Center aortic aneurysm database. The disease pattern, distribution, and operative mortality were determined. The annual incidence of AAA in Hong Kong is 13.7 per 100,000 population and 105 per 100,000 for those aged 65 and above. About 10% of the AAAs that presented were ruptured. The mean age of the AAA patients was 74 years, with 84% of them over age 65. The operative repair rate for AAAs was low, being only 8% for intact aneurysms and 54% for ruptured ones. Overall, 45% of all aneurysm repairs were performed for a ruptured AAA. There is diverse practice between major vascular centers and smaller regional hospitals. The territory-wide operative mortality rates for intact and ruptured aneurysms were 10% (range 4–24%) and 70% (range 38––100%), respectively. There was no gender bias in the rupture and operative rates. The overall mortality was 17% for intact AAAs and 78% for ruptured AAAs. The average length of hospital stay was 19 days for elective AAA surgery and 13 days for ruptured AAAs. The number of operations in high-volume centers is increasing with a concomitant decrease in operative mortality. There are no definitive data to indicate that the incidence of AAAs is rising, but a trend toward an increasing number of operations in referral centers is noted. The low repair rates for intact AAAs and the high proportion of repairs for ruptured aneurysms suggest that AAAs are undertreated in Hong Kong.     

Epidemiological study of the relationship between volume and outcome after abdominal aortic aneurysm surgery in the UK from 2000 to 2005

BACKGROUND: The aim was to assess the relationship between hospital volume and outcome after abdominal aortic aneurysm (AAA) surgery in the UK. METHODS: Hospital Episode Statistics (2000-2005) were classified as elective, urgent or ruptured AAA repair. Analysis was by modelling of mortality rate, complication rate and length of hospital stay with regard to the annual operative volume, after risk adjustment. RESULTS: There were 112,545 diagnoses, or repairs, of AAAs, of which 26,822 were infrarenal aneurysms. The mean mortality rate was 7.4, 23.6 and 41.8 per cent for elective, urgent and ruptured AAA repair respectively. Elective AAA repair undertaken at high-volume hospitals showed volume-related improvements in mortality (P < 0.001). Patients were discharged from hospital earlier (P < 0.001). The critical volume threshold was 32 elective AAA repairs per year. For urgent repair, patients at high-volume hospitals had a reduced mortality rate (P = 0.017) with an increased length of stay (P = 0.041). There was no relationship between volume and outcome for ruptured AAA repairs. CONCLUSION: Increased annual volumes were associated with significant reductions in mortality for elective and urgent AAA repair, but not for repair of ruptured AAAs.     

Operative treatment of abdominal aortic aneurysms in octogenarians. When is it too much too late?

OBJECTIVE: This study evaluated the value of operation for treatment of all octogenarians with ruptured abdominal aortic aneurysms (AAA). SUMMARY BACKGROUND DATA: Elective AAA resection in octogenarians is safe, with published operative mortality rates of approximately 5%. Published operative mortality rates of ruptured AAA in this age group, however, vary from 27 to 92%. METHODS: To evaluate this question, we extracted the clinical course of the 34 octogenarians submitted to AAA resection by the authors from our total experience of 548 resections performed during the past 7 1/2 years. In this subgroup of octogenarians, 18 underwent elective AAA replacement, 5 were submitted to urgent resection of active but intact AAAs, and 11 had operations for ruptured AAAs. There were 23 males and 11 females in the group. The ages ranged from 80 to 91 years. RESULTS: Operative mortality in the patients managed electively was 5.6%. Two of the five patients (40%) submitted to operation for active yet unruptured aneurysms died in the preoperative period. Finally, 10 of the 11 patients (91%) with ruptured AAAs were operative mortalities. All of these operative mortalities in the ruptured AAA subgroup had severe hypotension preoperatively (mean systolic blood pressure: 23 mm Hg). The charges associated with the management of the ruptured AAA group averaged $84,486 (range $12,537-$199,233). CONCLUSIONS: Although elective replacement of AAA in properly selected octogenarians appears valuable to prolong worthwhile life expectancy, this experience leads us to consider observation only in the treatment of octogenarians with ruptured AAA who present with severe hemodynamic instability.     

Hospital resource use and costs among abdominal aortic aneurysm repair patients admitted to the intensive care unit

BackgroundAbdominal aortic aneurysm (AAA) repair is associated with significant morbidity and mortality. As a result, many of these patients are monitored postoperatively in the intensive care unit (ICU). However, little is known about resource utilization and costs associated with ICU admission in this population. We sought to evaluate predictors of total costs among patients admitted to the ICU after repair of nonruptured or ruptured AAA.MethodsWe retrospectively analyzed prospectively collected data (2011-2016) of ICU patients admitted after AAA repair. The primary outcome was total hospital costs. We used elastic net regression to identify pre-ICU admission predictors of hospitalization costs separately for nonruptured and ruptured AAA patients.ResultsWe included 552 patients in the analysis. Of these, 440 (79.7%) were admitted after repair of nonruptured AAA, and 112 (20.3%) were admitted after repair of ruptured AAA. The mean age of patients with nonruptured AAA was 74 (standard deviation, 9) years, and the mean age of patients with ruptured AAA was 70 (standard deviation, 8) years. Median total hospital cost (in Canadian dollars) was $21,555 (interquartile range, $17,798-$27,294) for patients with nonruptured AAA and $33,709 (interquartile range, $23,173-$53,913) for patients with ruptured AAA. Among both nonruptured and ruptured AAA patients, increasing age, illness severity, use of endovascular repair, history of chronic obstructive pulmonary disease, and excessive blood loss (≥4000 mL) were associated with increased costs, whereas having an anesthesiologist with vascular subspecialty training was associated with lower costs.ConclusionsPatient-, procedure-, and clinician-specific variables are associated with costs in patients admitted to the ICU after repair of AAA. These factors may be considered future targets in initiatives to improve cost-effectiveness in this population.     

Payer status is related to differences in access and outcomes of abdominal aortic aneurysm repair in the United States: Boxter LK,Dimick JB,Wainess RM,et al. Surgery 2003;134L:142-5

ConclusionThere were greater operative mortality rates in uninsured patients for both elective and emergent abdominal aortic aneurysm (AAA) repair. Uninsured patients underwent treatment for ruptured AAAs more often than did patients with private insurance.SummaryThe authors studied whether patients with private insurance, compared with patients with Medicaid or no insurance, differ with respect to outcome of AAA repair and timely access to treatment of AAA.The national inpatient procedure diagnostic codes for AAA repair, intact and ruptured, were examined for 5363 patients younger than 65 years, from 1995 to 2000, with risk-adjusted analyses for access to AAA treatment and outcomes of repair. Dependent variables included in-hospital mortality, ruptured AAA, and intact AAA. Independent variables were comorbid disease, gender, age, race, payer status, and median income.Patients with no insurance or Medicaid were more likely to have AAA rupture (P < .001). Patients without insurance were at increased risk for rupture compared with patients with private insurance (odds ratio, 2.3; 95% confidence interval, 1.5-3.5; P < .001). Operative mortality rates appeared greater after elective AAA repair in patients with no insurance or Medicaid compared with patients with private insurance. Operative mortality rates were also higher after ruptured AAA repair in patients without insurance or Medicaid.CommentAdditional analyses are needed to determine whether patients without insurance or with Medicaid tend to avoid health care because of the financial burden or whether delayed access to surgical treatment results from gate-keeping issues or other deterrents to health care among patients with no insurance or Medicaid.     

Payer status is related to differences in access and outcomes of abdominal aortic aneurysm repair in the United States

BACKGROUND: The hypothesis of this study was that differences exist among patients with private insurance compared with patients with Medicaid or no insurance, regarding access to the timely treatment of abdominal aortic aneurysms (AAAs) and the outcomes of AAA repair. METHODS: The study comprised 5363 patients aged less than 65 years (mean age, 59 years) with a diagnostic code for intact or ruptured AAA and a procedure code for AAA repair in the National Inpatient Sample for 1995 to 2000. Dependent variables included ruptured AAA, intact AAA, and in-hospital postoperative mortality rates. Independent variables included payer status, median income, race, gender, age, and comorbid disease. Risk-adjusted analyses were performed with the use of binary logistic regression. RESULTS: AAA rupture was most likely (P <.001) to affect patients with no insurance (36%) or Medicaid (18%), compared with patients with private insurance (13%). After an adjustment for case-mix had been made, data showed that patients without insurance had an increased risk of rupture compared with patients with private insurance (odds ratio, 2.3; 95% CI, 1.5-3.5; P <.001). Operative mortality rates after elective AAA repair were greater (P =.04) for patients with no insurance (2.6%) or Medicaid (2.7%), compared with patients with private insurance (1.2%). Similarly, operative mortality rates for AAA repair after rupture were greater (P =.001) in patients without insurance (45.3%) or Medicaid (31.3%), compared with patients with private insurance (26.2%). CONCLUSIONS: Uninsured patients more often seek treatment of ruptured AAAs compared with patients with private insurance. Operative mortality rates in uninsured patients are greater for elective and emergent AAA repair. These data support the tenet that payer status is associated with mortality rates after AAA repair.     

Epidemiology of surgically treated abdominal aortic aneurysms in the United States, 1988 to 2000

Abdominal aortic aneurysm (AAA) repair is a complex procedure about which little information exists regarding trends in surgical practice in the United States. This study was undertaken to define benchmark data regarding performance and outcomes of conventional AAA repair that might be used in comparisons with endovascular AAA repair data. Patients undergoing repair of intact (n = 87,728) or ruptured (n = 16,295) AAAs in the Nationwide Inpatient Sample (NIS) for 1988 to 2000 were studied. The NIS represents a 20% stratified random sample of all discharges from US hospitals. Unadjusted and case mix-adjusted analyses of in-hospital mortality and length of stay were performed. The overall frequency of intact AAA repair remained relatively stable during the study period, ranging from 18.1 to 16.3 operations/100,000 adults between 1988 and 2000, respectively. The operative mortality rate for intact AAA repair decreased significantly (p < .001) from 6.5% in 1988 to 4.3% in 2000. Length of stay following intact AAA repair also declined significantly (p < .001) from a median of 11 days in 1988 (interquartile range [IQR] 9-15 days) to 7 days in 2000 (IQR 5-10 days). The incidence of ruptured AAA repair decreased significantly (p < .001) from 4.2 to 2.6 operations/100,000 adults between 1988 and 2000, respectively. Mortality for ruptured AAA repair, averaging 45.6%, did not decrease significantly during the study period. Intact AAA repair by conventional means has become increasingly safe, with decreased operative mortality and shorter hospital stays. Ruptured AAA repair by conventional means has not become safer but has decreased in incidence, suggesting possible reductions in risk factors contributing to rupture, coupled with more timely intact AAA repairs.     

Elective Versus Ruptured Abdominal Aortic Aneurysm Repair: A 1-Year Cost-Effectiveness Analysis

Abdominal aortic aneurysm (AAA) is a life-threatening condition with an overall mortality of 80%. It predominantly affects men 65-74 years of age and is caused by focal distension of the main blood vessel in the abdomen. Most patients go undetected until their aneurysm ruptures. Controversy surrounds the most appropriate form of screening for AAA. Currently, screening is only carried out selectively in patients with peripheral vascular disease. Some patients have their AAA detected incidentally, whilst ultrasound examination of the abdomen is carried out for other indications. These patients have the opportunity to undergo surveillance or elective surgery. The mortality rate of emergency surgical intervention following rupture (50%) is far worse in comparison to that of patients undergoing planned intervention under specialist vascular surgeons (5%). Despite improvements in outcomes from elective intervention for AAA as a result of specialisation, the overall mortality from this condition remains very high (80%) as the commonest presentation of an AAA is rupture. Screening all men aged 65-74 years is considered too costly in the current economic climate. However the cost difference between elective repair and emergency repair of AAA must be considered given that the outcome from elective AAA repair is far superior to that following ruptured AAA repair. Our objective was to retrospectively collect costs and outcomes of elective and emergency AAA repair in order to carry out a cost-effectiveness analysis. Four multiprofessional teams in accident and emergency, operation theatres, intensive care, and surgical wards at the Kent and Canterbury Hospital were selected from health-care professionals including doctors, managers, nurses, and clerical staff with the purpose of obtaining costs. Detailed cost data collection sheets were prepared to calculate costs, which included staff costs, consumables including drugs, intravenous fluids, equipment, investigations, laundry, catering, and stationery. An inventory of costs per item was obtained, and the total cost was calculated from the number of items used. Outcomes were measured in terms of survival. The total costs of emergency AAA repair were ￡96,700.69, with a cost per life saved of ￡24,175.17. The total cost of elective AAA repair was ￡76,583.22, with a cost per life saved of ￡5,470.23. Emergency intervention for AAA was found to cost five times more than a planned intervention per life saved per year.     

Ruptured inflammatory abdominal aortic aneurysm: insights in clinical management and outcome

BACKGROUND: Ruptured inflammatory abdominal aortic aneurysm (AAA) is relatively rare, and little has been written on the outcome of operative treatment. METHODS: Patients undergoing attempted repair of ruptured inflammatory AAA between 1995 and 2001 were included in a retrospective case-cohort study. Demographic, clinical, and operative factors were analyzed, together with in-hospital morbidity, in-hospital mortality, and duration of postoperative hospital stay. RESULTS: Of 297 patients who underwent attempted operative repair of ruptured AAA, 24 (8%) had an inflammatory aneurysm. Twenty-two patients were men, and two were women; median age was 69 years (range, 51-85 years). Operative findings revealed a contained hematoma in 16 patients (70%), free rupture in 3 patients (13%), aortocaval fistula in 4 patients (17%), and aortoenteric fistula in 1 patient (4%). Of 273 noninflammatory ruptured AAAs, only 2 AAA (1%) were associated with primary aortic fistula. Ten patients (42%) with inflammatory AAA died in hospital, compared with 117 of 273 patients (43%) without inflammation. Median postoperative stay was 10 days (range, 0-35 days). Of the 14 patients with inflammatory lesions who survived, 11 had postoperative complications; 4 patients had acute renal failure, three of whom required temporary renal replacement therapy. CONCLUSIONS: Ruptured inflammatory AAA is associated with a higher incidence of aortic fistula than is ruptured noninflammatory AAA. Repair of ruptured inflammatory AAA is not associated with increased operative mortality compared with repair of ruptured noninflammatory AAA.     

Is carotid endarterectomy cost-effective in symptomatic patients with moderate (50% to 69%) stenosis?

OBJECTIVE: Recently published data from the North American Carotid Endarterectomy Trial revealed a benefit for carotid endarterectomy (CEA) in symptomatic patients with moderate (50% to 69%) carotid stenosis. This benefit was significant but small (absolute stroke risk reduction at 5 years, 6.5%; 22.2% vs 15.7%), and thus, the authors of this study were tentative in the recommendation of operation for these patients. To better elucidate whether CEA in symptomatic patients with moderate carotid stenosis is a proper allocation of societal resources, we examined the cost-effectiveness of this intervention. METHODS: A decision-analytic Markov process model was constructed to determine the cost-effectiveness of CEA versus medical treatment for a hypothetical cohort of 66-year-old patients with moderate carotid stenosis. This model allowed the comparison of not only the immediate hospitalization but also the lifetime costs and benefits of these two strategies. Our measure of outcome was the cost-effectiveness ratio (CER), defined as the incremental lifetime cost per quality-adjusted life year saved. We assumed an operative stroke and death rate of 6.6% and a declining risk of ipsilateral stroke after the ischemic event with medical treatment (first year, 9.3%; second year, 4%; subsequent years, 3%). The hospitalization cost of CEA ($6,420) and the annual costs of major stroke ($26,880), minor stroke ($798), and aspirin therapy ($63) were estimated from a hospital cost accounting system and the literature. RESULTS: CEA for moderate carotid stenosis increased the survival rate by 0.13 quality-adjusted life years as compared with medical treatment at an additional lifetime cost of $580. Thus, CEA was cost-effective with a CER of $4,462. Society is usually willing to pay for interventions with CERs of less than $60,000 (eg, CERs for coronary artery bypass grafting at $9,100 and for dialysis at $53,000). CEA was not cost-effective if the perioperative risk was greater than 11.3%, if the ipsilateral stroke rate associated with medical treatment at 1 year was reduced to 4.3%, if the age of the patient exceeded 83 years, or if the cost of CEA exceeded $13,200. CONCLUSION: CEA in patients with symptomatic moderate carotid stenosis of 50% to 69% is cost-effective. Perioperative risk of stroke or death, medical and surgical stroke risk, cost of CEA, and age are important determinants of the cost-effectiveness of this intervention.     

Predictors of repair and effect of gender on treatment of ruptured abdominal aortic aneurysm

OBJECTIVE: The purpose of this study was to determine factors associated with increased likelihood of patients undergoing surgery to repair ruptured abdominal aortic aneurysms (AAAs). Specifically, we investigated whether men were more likely than women to be selected for surgery after rupture of AAAs. METHODS: All patients with a ruptured AAA who came to a hospital in Ontario between April 1, 1992, and March 31, 2001, were included in this population-based retrospective study. Administrative data were used to identify patients, patient demographic data, and hospital variables. RESULTS: Crude 30-day mortality for the 3570 patients who came to a hospital with a ruptured AAA was 53.4%. Of the 2602 patients (72.9%) who underwent surgical repair, crude 30-day mortality was 41.0%. Older patients (odds ratio [OR], 0.649 per 5 years of age; P<.0001), with a higher Charlson Comorbidity Index (OR, 0.848; P<.0001), were less likely to undergo AAA repair. Patients treated at high-volume centers (OR, 2.674 per 10 cases; P<.0001) and men (OR, 2.214; P<.0001) were more likely to undergo AAA repair. CONCLUSION: Men are more likely to undergo repair of a ruptured AAA than women are, for reasons that are unclear. Given the large magnitude of the effect, further studies are clearly indicated.     

Meta-analysis and systematic review of the relationship between volume and outcome in abdominal aortic aneurysm surgery

BACKGROUND: This study investigated the volume-outcome relationship for abdominal aortic aneurysm (AAA) surgery and quantified critical volume thresholds. METHODS: PubMed, EMBASE and the Cochrane library were searched for articles on the operation volume-outcome relationship in elective and ruptured AAA surgery. UK Hospital Episode Statistics data were also considered. Elective and ruptured AAA repairs were dealt with separately. The data were meta-analysed, and the odds ratios (95 per cent confidence interval) for mortality at higher- and lower-volume hospitals were compared. Volume thresholds were identified from each paper. RESULTS: The analysis included 421,299 elective and 45,796 ruptured AAA operations. Significant relationships between mortality and annual volume were noted for both groups. Overall, the weighted odds ratio was 0.66 (0.65 to 0.67) for elective repair at a threshold of 43 AAAs per annum and 0.78 (0.73 to 0.82) for ruptured aneurysm repair at a threshold of 15 AAAs per annum, both in favour of high-volume institutions. CONCLUSION: Higher annual operation volumes are associated with significantly lower mortality in both elective and ruptured AAA repair. This suggests that AAA surgery should be performed only at higher-volume centres.     

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.     

Universal Screening for Malnutrition Prior to Total Knee Arthroplasty Is Cost-Effective: A Markov Analysis

BackgroundPatients undergoing total knee arthroplasty (TKA) who have malnutrition possess an increased risk of periprosthetic joint infection (PJI). Although malnutrition screening and intervention may decrease the risk of PJI, it utilizes healthcare resources. To date, no cost-effectiveness analyses have been performed on the screening and treatment of malnutrition prior to TKA.MethodsA Markov model projecting lifetime costs and quality-adjusted life years (QALYs) was built to determine the cost-effectiveness of malnutrition screening and intervention for TKA patients from a societal perspective. Costs, health state utilities, and state transition probabilities were obtained from previously published literature, hospital costs at our institution, and expert opinions. Two important assumptions included that 30% of patients would be malnourished and that a malnutrition intervention would be 50% effective. The primary outcome of this study was the incremental cost-effectiveness ratio, with a willingness-to-pay threshold of $100,000 per QALY. One-way and two-way sensitivity analyses were performed to evaluate model parameter assumptions.ResultsWhen using the base case values, universal malnutrition screening and intervention was cost-effective compared to no malnutrition screening or intervention, with an incremental cost-effectiveness ratio of $6,454 per QALY. Universal screening and intervention remained cost-effective, provided the cost of screening remained less than $3,373, the cost of nutritional intervention remained less than $12,042, the prevalence of malnutrition among surgical candidates was higher than 2%, and the risk of PJI among patients with malnutrition was greater than 1%.ConclusionUniversal preoperative malnutrition screening and intervention among TKA candidates is cost-effective at parameters encountered in clinical practice. Nutritional optimization programs should be considered to facilitate malnutrition screening and intervention and future studies should evaluate their efficacy at lowering PJI risk.     

Use of sequential B-mode ultrasonography to manage abdominal aortic aneurysms

The utility and safety of sequential B-mode ultrasonography to treat male patients with small (less than 6.0 cm in diameter) abdominal aortic aneurysms (AAAs) were studied retrospectively in 149 consecutive patients. Sixty-three of these patients have had operative repair of the AAA. Eight-six remain unoperated on. Mean growth rate was 0.79 cm/y (1.06 cm/y in the operated-on group and 0.36 cm/y in the unoperated-on group). Seven patients sustained rupture of the AAA during follow-up and 4 patients died as a consequence of elective repair, for a combined mortality rate of 7.4% (11/149). Only one AAA that was less than 5.0 cm ruptured. This has proved to be an effective way to manage AAAs in this population.     

The cost-effectiveness of a "quick-screen" program for abdominal aortic aneurysms

BACKGROUND: The incidence of abdominal aortic aneurysm (AAA) is increasing, and the prognosis of ruptured AAA remains dismal. Early diagnosis and intervention are crucial. We designed this study to determine whether selected population screening with a brief "quick-screen" ultrasound could be cost-effective. METHODS: A series of 25 patients with risk factors for AAA were evaluated in a blinded fashion by a quick-screen ultrasound and a full conventional study. Times and accuracy for the 2 approaches were compared. An analysis of the cost-effectiveness of screening for AAA was then performed using a Markov model. We determined the long-term survival in quality-adjusted life years and lifetime costs for a hypothetical cohort of 70-year-old males undergoing either AAA screening or not. Our measure of outcome was the cost-effectiveness ratio (CER). RESULTS: The average time for a quick screen was one-sixth that of a conventional study (4 vs 24 minutes). The accuracy of the quick screen was 100%. In our base-case analysis, screening for AAA was cost-effective with a CER of $11,215. Society usually is willing to pay for interventions with CER of less than $60,000 (eg, CER for coronary artery bypass grafting, $9500; breast cancer screening, $16,000). In sensitivity analysis, reducing the cost of screening from $259 (approximate Medicare reimbursement) to $40 (the quick screen) improved the CER to $6850. Moreover, screening populations with increased prevalence of AAA (eg, male with family history [18%]) further improved the CER. CONCLUSIONS: Our analysis demonstrates that ultrasound screening for AAA should be offered to all males above the age of 60. Widespread screening for AAA should be adopted and reimbursed by Medicare and other insurers.