Operative mortality and long-term relative survival of patients operated on for asymptomatic abdominal aortic aneurysm

Does Specialization Improve Outcome in Abdominal Aortic Aneurysm Surgery?

Specialization and high volume are reported to be related to a better outcome after abdominal aortic aneurysm repair. The aim of this study was to compare, in patients undergoing abdominal aortic aneurysm repair, the outcomes of those whose surgery was done by general surgeons with the outcomes of those whose surgery was done by specialist vascular surgeons.

All patients undergoing abdominal aortic aneurysm repair at the Basel University Hospital (referral center) from January 1990 to December 2000 were included. Patients with endovascular treatment were excluded.

Operations in group A ( n = 189), between January 1990 and May 1995, were done by general surgeons. Operations in group B ( n = 291), between June 1995 and December 2000, were done by vascular surgeons.

In-hospital mortality and local and systemic complications were assessed.

In-hospital mortality rates were significantly lower for group B (with specialist surgeons) than for group A, both overall (group B, 11.7%; group A, 21.7%; p = .003) and for emergency interventions (group B, 28.1%; group A, 41.9%; p = .042). The reduction in mortality for elective surgery in group B was not statistically significant (group B, 1.1%; group A, 4.9%; p = .054). There were significantly fewer pulmonary complications in group B compared with group A ( p = .000).

We conclude that in patients undergoing abdominal aortic aneurysm repair, those whose surgery is done by a specialized team have a significantly better outcome than those whose surgery is done by general surgeons.

Calculating when elective abdominal aortic aneurysm repair improves survival for individual patients: development of the Aneurysm Repair Decision Aid and economic evaluation

BACKGROUND

Abdominal aortic aneurysm (AAA) repair aims to prevent premature death from AAA rupture. Elective repair is currently recommended when AAA diameter reaches 5.5 cm (men) and 5.0 cm (women). Applying population-based indications may not be appropriate for individual patient decisions, as the optimal indication is likely to differ between patients based on age and comorbidities.

OBJECTIVE

To develop an Aneurysm Repair Decision Aid (ARDA) to indicate when elective AAA repair optimises survival for individual patients and to assess the cost-effectiveness and associated uncertainty of elective repair at the aneurysm diameter recommended by the ARDA compared with current practice.

DATA SOURCES

The UK Vascular Governance North West and National Vascular Database provided individual patient data to develop predictive models for perioperative mortality and survival. Data from published literature were used to model AAA growth and risk of rupture. The cost-effectiveness analysis used data from published literature and from local and national databases.

METHODS

A combination of systematic review methods and clinical registries were used to provide data to populate models and inform the structure of the ARDA. Discrete event simulation (DES) was used to model the patient journey from diagnosis to death and synthesised data were used to estimate patient outcomes and costs for elective repair at alternative aneurysm diameters. Eight patient clinical scenarios (vignettes) were used as exemplars. The DES structure was validated by clinical and statistical experts. The economic evaluation estimated costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) from the NHS, social care provider and patient perspective over a lifetime horizon. Cost-effectiveness acceptability analyses and probabilistic sensitivity analyses explored uncertainty in the data and the value for money of ARDA-based decisions. The ARDA outcome measures include perioperative mortality risk, annual risk of rupture, 1-, 5- and 10-year survival, postoperative long-term survival, median life expectancy and predicted time to current threshold for aneurysm repair. The primary economic measure was the ICER using the QALY as the measure of health benefit.

RESULTS

The analysis demonstrated it is feasible to build and run a complex clinical decision aid using DES. The model results support current guidelines for most vignettes but suggest that earlier repair may be effective in younger, fitter patients and ongoing surveillance may be effective in elderly patients with comorbidities. The model adds information to support decisions for patients with aneurysms outside current indications. The economic evaluation suggests that using the ARDA compared with current guidelines could be cost-effective but there is a high level of uncertainty.

LIMITATIONS

Lack of high-quality long-term data to populate all sections of the model meant that there is high uncertainty about the long-term clinical and economic consequences of repair. Modelling assumptions were necessary and the developed survival models require external validation.

CONCLUSIONS

The ARDA provides detailed information on the potential consequences of AAA repair or a decision not to repair that may be helpful to vascular surgeons and their patients in reaching informed decisions. Further research is required to reduce uncertainty about key data, including reintervention following AAA repair, and assess the acceptability and feasibility of the ARDA for use in routine clinical practice.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Survival after repair of pararenal and paravisceral abdominal aortic aneurysms

OBJECTIVE

The objective of this study was to review our 27-year clinical experience with open proximal abdominal aortic aneurysm repairs, with a focus on long-term survival.

METHODS

A retrospective cohort study was undertaken of all patients who underwent proximal abdominal aortic aneurysm repair between 1986 and 2013 at a tertiary care referral center. Demographics, operative variables, complications, and 30-day mortality were analyzed. Postoperative acute kidney injury was analyzed by the RIFLE (Risk, Injury, Failure, Loss, End-stage renal disease)/Acute Kidney Injury Network criteria. Long-term survival was assessed through review of electronic medical records and the Social Security Death Index. Associations between demographics and complications were investigated to determine predictors of long-term survival.

RESULTS

The study identified 245 patients. Mean age was 71 years (range, 38-92 years); 69% were men, and 88% were white. Aneurysm type was juxtarenal in 127 patients (52%), suprarenal in 68 patients (28%), and type IV thoracoabdominal in 50 patients (20%). In-hospital mortality was 3.3% (eight patients), and 30-day mortality was 2.9% (seven patients). At least one major complication occurred in 64% of the patients, which included the following: acute kidney injury, 60% (persistent acute kidney injury at discharge, however, was 28%, and hemodialysis at discharge was 1.6%); major pulmonary complications, 22%; myocardial infarction, 4%; visceral ischemia, 2%; and paraplegia, 0.5%. Median follow-up was 54 months. Kaplan-Meier survival estimates were 70% at 5 years and 43% at 10 years. Variables associated with poorer survival included congestive heart failure (hazard ratio [HR], 3.5; P < .001), chronic obstructive pulmonary disease (HR, 1.8; P < .002), and increased aneurysm size at presentation (HR, 1.1; P < .013). Persistent stage 3 acute kidney injury was associated with poor long-term survival.

CONCLUSIONS

Open surgical repair of proximal abdominal aortic aneurysms can be performed with low mortality. Acute kidney injury is the most frequent complication, but the need for hemodialysis at discharge is low. Long-term survival is favorable. These data should assist in establishing benchmarks for endovascular repair of complex proximal abdominal aortic aneurysms.

Lowered postoperative ldl-c/hdl-C ratio reduces later cardiovascular events after abdominal aortic aneurysm surgery

PURPOSE

To examine the relationship between the incidence of later cardiovascular events after abdominal aortic aneurysm (AAA) surgery and postoperative lipid levels.

METHODS

Atherosclerotic risk factors including postoperative serum lipid levels were examined in 116 patients aged 70 or less undergoing an elective AAA surgery. Later cardiovascular events after AAA surgery occurred in 21 patients, including cerebral infarction (n = 4), catheter intervention or surgery for coronary artery disease (CAD) (n = 10) and other vascular disease.

RESULTS

Postoperative cholesterol levels during the average follow-up period of 55.6 ± 44.3 (months) were 49.0 ± 15.7 (mg/dL) for high-density lipoprotein cholesterol (HDL-C), 97.9 ± 31.2 (mg/dL) for low-density lipoprotein cholesterol (LDL-C), which were both significantly improved compared to preoperative values (p <0.001). Cox hazard analysis indicated that preexistent CAD significantly increased in the risk for later cardiovascular events (hazard ratio 5.67; 95%CI 1.92-16.8; p = 0.002) and lowered postoperative LDL-C/HDL-C ratio <1.5 decreased in the risk after AAA surgery (hazard ratio 0.10; 95%CI 0.01-0.83; p = 0.033). Patients with postoperative LDL-C/HDL-C ratio <1.5 (n = 22) had a significantly better cardiovascular event-free rate than those with that ratio ≥1.5 (n = 94) (p = 0.014).

CONCLUSION

Lowered postoperative LDL-C/HDL-C ratio <1.5 can decrease in the risk for later cardiovascular events after AAA surgery. These results may support the rationale for postoperative aggressive lipid-modifying therapy.

Improved Long-Term Survival After Abdominal Aortic Aneurysm Repair

Background— Treatment of abdominal aortic aneurysm (AAA) has changed significantly over the past 2 decades. In this perspective, time trends in long-term survival were studied.

Methods and Results— We identified 8663 primary intact and 4171 ruptured AAA repairs in the Swedish Vascular Registry from 1987 to 2005. Mortality was obtained from the national population registry. Crude survival was analyzed, including all mortality. To analyze the long-term outcome among those surviving the AAA repair, relative survival, which denotes the survival rate of patients compared with that of the general population adjusted for age, sex, and calendar year, was calculated, excluding 90-day mortality. In a comparison of AAA repairs from 1987 to 1999 and 2000 to 2005, age (71.4 versus 72.5 years; P <0.001), patients with comorbidities (65.0% versus 68.5%; P <0.001), and endovascular repair (1.6% versus 17.0%; P <0.001) increased. After intact AAA repair, crude 5-year survival was 69.0% (99% confidence interval [CI], 67.7 to 70.4), and relative 5-year survival excluding 90-day mortality was 90.3% (99% CI, 88.6 to 92.0). Relative 5-year survival was better for those operated on from 2000 to 2005 compared with 1987 to 1999 (difference, 4.7%; 99% CI, 1.3 to 8.1), for men versus women (4.6%; 99% CI, 0.4 to 8.8), and for octogenarians versus patients <80 years of age (10.2%; 99% CI, 1.5 to 18.8); no difference was observed between open and endovascular repair (6.0%; 99% CI, −1.5 to 13.4). After ruptured AAA repair, crude 5-year survival was 41.7% (99% CI, 39.6 to 43.7) and relative 5-year survival was 87.1% (99% CI, 83.9 to 90.3). No significant differences in relative 5-year survival were observed between time periods, sex, or age groups.

Conclusions— Long-term survival improved over time after intact AAA repair despite a change in case mix toward older patients with more comorbidities. Long-term survival was stable after ruptured AAA repair.

Final 12-year follow-up of Surgery versus Surveillance in the UK Small Aneurysm Trial

Background

The aim was to determine whether early open surgical repair would benefit patients with small abdominal aortic aneurysm compared with surveillance on long-term follow-up.

Methods

The 1090 patients who were enrolled into the UK Small Aneurysm Trial between 1991 and 1995 were followed up for aneurysm repair and mortality until November 2005.

Results

By November 2005, 714 patients (65·5 per cent) had died, 929 (85·2 per cent) had undergone aneurysm repair, 150 (13·8 per cent) had died without aneurysm repair and 11 (1·0 per cent) remained alive without aneurysm repair. After 12 years, mortality in the surgery and surveillance groups was 63·9 and 67·3 per cent respectively, unadjusted hazard ratio 0·90 (P = 0·139). Three-quarters of the surveillance group eventually had aneurysm repair, with a 30-day elective mortality of 6·3 per cent (versus 5·0 per cent in the early surgery group, P = 0·366). Estimates suggested that the cost of treatment was 17 per cent higher in the early surgery group, with a mean difference of £1326. The death rate in these patients was about twice that in the population matched for age and sex.

Conclusion

There was no long-term survival benefit of early elective open repair of small abdominal aortic aneurysms. Even after successful aneurysm repair, the mortality among these patients was higher than in the general population.

Elective surgery for aortic abdominal aneurysm: comparison of English outcomes with those elsewhere

INTRODUCTION

The aim of this study was to quantify mortality after elective repair of abdominal aortic aneurysm (AAA) in England, and to compare English case fatality rates (CFRs) with those reported in the literature.

PATIENTS AND METHODS

English Hospital Episode Statistics (HES) for the financial years 1998/9 to 2001/2, linked to death data, were analysed. A systematic literature search was undertaken to identify studies reporting CFRs after elective AAA surgery. The CFR in England was compared with these studies by using confidence intervals on the CFRs and funnel plot techniques.

RESULTS

In the English study, elective repair of AAA was performed on 11,338 patients of whom 771 died within 30 days after surgery (6.8%). The literature search found 66 studies: 34 reported mortality rates that were within the 99% confidence limits of the English rates, 31 below, and one study above.

DISCUSSION

The CFR after elective surgical repair in England within 30 days of operation (6.8%) was higher than expected from the literature. Differences between England and other countries in quality of care is one possible explanation for the findings, but other explanations are possible and are discussed.

Determinants of long-term survival after major surgery and the adverse effect of postoperative complications

OBJECTIVE

The objective of this study was to identify the determinants of 30-day postoperative mortality and long-term survival after major surgery as exemplified by 8 common operations.

SUMMARY BACKGROUND DATA

The National Surgical Quality Improvement Program (NSQIP) database contains pre-, intra-, and 30-day postoperative data, prospectively collected in a standardized fashion by a dedicated nurse reviewer, on major surgery in the Veterans Administration (VA). The Beneficiary Identification and Records Locator Subsystem (BIRLS) is a VA file that depicts the vital status of U.S. veterans with 87% to 95% accuracy.

METHODS

NSQIP data were merged with BIRLS to determine the vital status of 105,951 patients who underwent 8 types of operations performed between 1991 and 1999, providing an average follow up of 8 years. Logistic and Cox regression analyses were performed to identify the predictors of 30-day mortality and long-term survival, respectively.

RESULTS

The most important determinant of decreased postoperative survival was the occurrence, within 30 days postoperatively, of any one of 22 types of complications collected in the NSQIP. Independent of preoperative patient risk, the occurrence of a 30-day complication in the total patient group reduced median patient survival by 69%. The adverse effect of a complication on patient survival was also influenced by the operation type and was sustained even when patients who did not survive for 30 days were excluded from the analyses.

CONCLUSIONS

The occurrence of a 30-day postoperative complication is more important than preoperative patient risk and intraoperative factors in determining the survival after major surgery in the VA. Quality and process improvement in surgery should be directed toward the prevention of postoperative complications.

Cost-effectiveness of different screening strategies for abdominal aortic aneurysm

OBJECTIVE

The primary objective of this study was to develop a simulation model to assess the cost-effectiveness of different screening strategies for abdominal aortic aneurysms (AAAs) in men.

METHODS

A systematic review of the literature was conducted for different screening strategies in terms of age (60, 65, or 70 years) and risk profiles (all men or specific high-risk groups) of the screened population, and rescreening after 5 or 10 years. These data were analyzed in a Markov simulation cohort model.

RESULTS

The cost per life year gained for different screening strategies ranged from US 8,309 dollars to US 14,084 dollars and was estimated at US 10,474 dollars when 65-year-old men were screened once. Screening 60-year-old men was equally cost-effective, with the advantage of more life years gained. We demonstrated a trade-off between high prevalence of AAA and lower life expectancy, eliminating the expected benefits of screening high-risk groups such as smokers (US 10,695 dollars) or cardiovascular patients (US 10,392 dollars). Assuming general population utility resulted in a cost per quality-adjusted life year (QALY) gained of US 13,900 dollars, whereas a hypothetical 5% reduction in utility among men with a screening-detected AAA raised the cost per QALY gained to US 75,100 dollars.

CONCLUSION

This Markov model, which was based on a systematic review of the literature, supplied information on the estimated cost-effectiveness of different screening strategies. Screening men for AAA may be cost-effective in the long-term. Different screening strategies and quality-of-life effects related to screening for AAA need to be evaluated in future clinical studies.

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.

Intra-mucosal acidosis as a predictor of cardiac outcome following abdominal aortic aneurysm surgery

OBJECTIVE

To assess if sigmoid ischaemia is a prognostic indicator of early and late post-operative cardiac morbidity and mortality.

MATERIALS AND METHODS

Patients undergoing elective abdominal aortic aneurysm repair (AAAR) were included in the study. Demographic details and risk factors for heart disease were recorded. Sigmoid pHi was measured at the time of surgery using a silicone tonometer and perioperative morbidity and mortality were recorded in all patients. Seven years following surgery the patients and their general practitioners were contacted to determine the patient's health.

RESULTS

Thirty-eight patients were included in the study. Within the follow-up period, 22 (58%) had died. Eight patients died of cardiac failure or myocardial infarction. The pHi in patients with cardiac related deaths [6.99 (6.84-7.10)] was significantly lower than those with non-cardiac related deaths [7.11 (7.04-7.21), p<0.05]. Similarly, patients who suffered acute cardiac events (within 30 days following AAA repair) had lower pHi [7.01 (6.88-7.12)] compared to those who did not [7.09 (6.90-7.19), p<0.05].

CONCLUSION

The results show that sigmoid ischaemia is more frequent amongst patients that develop cardiac events after AAAR and is associated with a worse long term outcome. This suggests that global hypoperfusion as a result of an under performing heart may be partly responsible for the sigmoid ischaemia in patients following AAAR. Therefore, low sigmoid pHi may predict an increased risk of cardiac complications in these patients.

Outcome after Abdominal Aortic Aneurysm Repair. Difference Between Men and Women

OBJECTIVES

To evaluate short- and long-term outcome after open repair for ruptured and non-ruptured abdominal aortic aneurysm (AAA) with special emphasis on the difference between men and women.

DESIGN

Single center retrospective study. Time and cause of death were determined from hospital charts, the National Bureau of Statistics and the Department for National Health and Welfare. Materials. Eight hundred and forty-six patients were followed-up, 597 were operated on for non-ruptured and 249 for ruptured aneurysms.

METHODS

Case fatality was analyzed by multiple logistic regression considering year of surgery, age at surgery, and gender as covariates. The mortality rate for patients surviving 60 days after surgery was compared with the mortality in the general population by calculating the standardised mortality ratio (SMR). Mortality was also stratified according to gender and type of surgery.

RESULTS

The SMR for patients surviving 60 days after surgery was significantly increased. SMR was significantly higher for women than for men. There was no statistically significant difference in SMR between patients operated for rupture compared to those operated for non-ruptured aneurysms.

CONCLUSIONS

Women with AAA have a poorer outcome than women in the general population. This finding may relate to the large number of risk factors present in this patient sub-group.

Guidelines for the treatment of abdominal aortic aneurysms. Report of a subcommittee of the Joint Council of the American Association for Vascular Surgery and Society for Vascular Surgery

Decision-making in regard to elective repair of abdominal aortic aneurysms (AAA) requires careful assessment of factors that influence rupture risk, operative mortality, and life expectancy. Individualized consideration of these factors in each patient is essential, and the role of patient preference is of increasing importance. It is not possible or appropriate to recommend a single threshold diameter for intervention which can be generalized to all patients. Based upon the best available current evidence, 5.5 cm is the best threshold for repair in an "average" patient. However, subsets of younger, good-risk patients or aneurysms at higher rupture risk may be identified in whom repair at smaller sizes is justified. Conversely, delay in repair until larger diameter may be best for older, higher-risk patients, especially if endovascular repair is not possible. Intervention at diameter <5.5 cm appears indicated in women with AAA. If a patient has suitable anatomy, endovascular repair may be considered, and it is most advantageous for older, higher-risk patients or patients with a hostile abdomen or other technical factors that may complicate standard open repair. With endovascular repair, perioperative morbidity and recovery time are clearly reduced; however, there is a higher reintervention rate, increased surveillance burden, and a small but ongoing risk of AAA rupture. There is no justification at present for different indications for endovascular repair, such as earlier treatment of smaller AAA. Until long-term outcome of endoluminal repair is better defined and results of randomized trials available, the choice between endovascular and open repair will continue to rely heavily on patient preference.

The fate of AAA patients referred electively to vascular surgical unit

BACKGROUND

The ideal treatment of abdominal aortic aneurysms (AAA) is to operate aneurysms likely to rupture, without exposing other cases to major surgery. The purpose here was to analyse retrospectively the management of AAA in a well-defined geographical region in the 1990's.

METHODS

194 new vascular surgical outpatient consultations due to AAA were done to the regional vascular centre during the years 1990, 1992, 1994, 1996 and 1998. Data were collected from case records. Statistics Finland provided causes and dates of death.

RESULTS

The mean observed annual AAA incidence was 9.0 per 100 000 inhabitants and it rose significantly (33.3%) during the study period. The duration of follow-up varied between 0 and 129 months. The 5/8-year cumulative mortality was 37.3/50.7%. The most common causes of death were AAA-related (31.7%), cardiac (29.1%) or malignancy (19.0%). Twenty-five patients with small AAA were referred to primary health care sector for further follow-up. There were no RAAA (ruptured AAA) deaths in this group. The cumulative 5/8-year mortality was 43.2/49.9%. One hundred patients underwent an elective aneurysm repair with in-hospital mortality of 7.0%. The cumulative 5/8-year mortality was 23.7/35.4%. Twelve patients refused elective treatment. The cumulative 5/8-year mortality was 45.1/ 63.4% and 5/7 deaths were due to RAAA. Twenty-three patients were unfit for elective repair. The cumulative 5/8-year mortality was 87.0%/100% and 5/20 deaths were caused by RAAA. The cumulative 5/8-year RAAA-rate in the patients with AAA more than 5.0 cm in diameter and outside elective aneurysm-repair (n = 23) was 51.9%/100.0%.

CONCLUSION

The observed incidence of AAA increased during the 1990's. Half of the patients underwent an elective procedure. Patients unfit for surgery died mainly for other reasons than RAAA. Most patients with AAA over 5.5 cm not subjected to elective procedure, died of rupture.

Laparoscopy-assisted abdominal aortic aneurysm repair: first case reports from Japan

Laparoscopy-assisted abdominal aortic aneurysm (AAA) repair consists of retroperitoneal laparoscopic dissection of the AAA and graft replacement performed via a mini-laparotomy. Two patients with infrarenal AAA underwent successful straight graft replacement using this hybrid approach. The retroperitoneal space was bluntly dissected under carbon dioxide pneumoretroperitoneum and further dissection was performed laparoscopically. This enabled proximal and distal control of the aneurysm, and occlusion of the lumbar arteries and the inferior mesenteric artery with hemoclips. A 7 cm mini-laparotomy was sufficient for the straight graft replacement. Laparoscopy-assisted repair is a less invasive technique for the treatment of AAA and can be regarded as the initial step towards totally endoscopic repair.

Adequate vascular training opportunities can be provided without compromising patient care

OBJECTIVES

to review the results of index operations in vascular surgery and to evaluate the impact of a specialist vascular training programme on patient outcome.

METHODS

we undertook a 5-year (January 1995-December 1999) review of the weekly-collected mortality and morbidity data. The total number, 30-day mortality and stroke rate of all index operations i.e. AAA repairs (ruptured and elective), carotid operations and infra-inguinal bypasses (above and below knee, elective and emergency) was recorded. The number of operations performed by trainees under supervision was recorded.

RESULTS

in the 5-year period 991 index operation were done of which 738 (74%) were done by trainees. Operations done by trainees were supervised by a consultant in 82% of cases with no significant effect on death or stroke rates. Overall vascular trainees performed 75% of the index operations of which 82% were supervised.

CONCLUSIONS

trainees under supervision performed three out of four index operations. The mortality and morbidity of index operations in our unit compared well with accepted best mortality and morbidity figures. Our unit provides good training opportunities for vascular trainees whilst maintaining satisfactory standards of patient care.

Comparison of cardiac troponin I and creatine kinase ratios in the detection of myocardial injury after aortic surgery

BACKGROUND

Perioperative myocardial infarction may not be diagnosed correctly because World Health Organization criteria are often not met and creatinine kinase myocardial fraction (creatinine kinase/creatinine kinase MB isoenzyme; CK/CK-MB) ratios can be difficult to interpret. Cardiac troponin (cTn) I and cTnT are the most sensitive and specific markers of myocardial cell necrosis currently available but are not widely used in surgical practice. The aim was to compare cTnI and CK/CK-MB ratios in the detection of myocardial injury following aortic surgery.

METHODS

This was a prospective study of 59 patients undergoing elective (n = 28) or ruptured (n = 24) abdominal aortic aneurysm repair or elective aortofemoral bypass (n = 7). cTnI level was measured before operation and at 6, 24 and 48 h after surgery. The CK/CK-MB ratio was measured where cTnI was detectable.

RESULTS

Some 14 of 24 emergency and ten of 35 elective patients had detectable cTnI (greater than 0.5 ng/ml) at one or more time-points. The CK/CK-MB ratio was greater than 5 per cent in only four of 24 patients having an emergency operation and in none of the elective patients with detectable cTnI.

CONCLUSION

Over half of patients undergoing emergency operation and more than a quarter of those having elective aortic surgery suffered myocardial necrosis as determined by detectable cTnI levels. This was accompanied by a raised CK/CK-MB ratio in less than one-fifth of patients.

Risk factors and operative results of patients aged less than 66 years operated on for asymptomatic abdominal aortic aneurysm

OBJECTIVE

To report risk factors, early operative results and survival after repair of asymptomatic abdominal aortic aneurysm (AAA) in patients aged less than 66 years.

DESIGN

a retrospective study based on a prospectively updated database in a University hospital.

PATIENTS AND METHODS

Between 1985 and 1999, 118 patients of less than 66 years were operated for AAA. Pre-operative risk factors, early complications, operative mortality (<30 days), and survival are compared with that of 333 older patients operated during the same period.

RESULTS

Risk factors were similar to older patients. Serious early (<30 days) complications were recorded in 20% of both groups. The operative mortality was 1.7% for the younger patients and 6% for the older (n.s.). The eight-year survival of the younger patients was 69%, which was significantly below that of a demographically matched population. The older patients had a significantly poorer eight-year survival of 47% (p<0.01), but their relative survival was significantly better (p<0.05).

CONCLUSIONS

Younger patients with an AAA were not healthier than older patients. Complications were equally common among both groups. Although the operative mortality was lower, the long-term relative survival was poorer than that of the older patient. Present data do not support a more aggressive surgical attitude towards the younger patients with an asymptomatic abdominal aortic aneurysm, as compared to the older.

Long-term relative survival following surgery for abdominal aortic aneurysm: a review

BACKGROUND

The literature reporting the long-term survival following surgery for abdominal aortic aneurysm (AAA) tends to be confusing. As a result, many clinicians looking after patients with AAA may be uncertain about the five-year survival of a given patient. This is in marked contrast to the situation for patients with malignant disease. With the current interest in population screening and endoluminal stenting for AAA, an understanding of long-term survival is increasingly important.

METHODS

Thirty two publications in the English language over the last 20 years, containing data pertaining to five-year survival following routine elective surgery for AAA in unselected patients, were identified using Medline searches.

RESULTS AND CONCLUSIONS

A range of important methodological differences were noted. The mean five-year crude survival was about 70% while the expected survival of a matched population was close to 80%. Survival was further reduced by about 10% in cases with significant coronary heart disease. Age alone is not a predictor of long-term relative survival with octogenarians who survive beyond 30 days surviving longer than an age-matched population.

Long-term survival following emergency abdominal aortic aneurysm repair

Survival following emergency surgery for ruptured abdominal aortic aneurysm remains poor and is in stark contrast to that for elective repair. We have carried out a 5-year retrospective observational study to determine the long-term (5-year) survival of patients following emergency surgery for ruptured abdominal aortic aneurysm at a district general hospital in East Anglia. A total of 99 patients presented to the operating theatre for emergency repair of ruptured abdominal aortic aneurysm in this 5-year study period. In-hospital mortality was 70% and was unchanged over the 5 years. Overall long-term survival in those patients discharged from hospital was good. The ICU cost per long-term survivor was calculated to be pound sterling 36750.

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.

Factors affecting late survival after elective abdominal aortic aneurysm repair

BACKGROUND

The late prognosis after repair of an abdominal aortic aneurysm (AAA) may be affected by atherosclerosis, which involves various organs including the aorta.

METHODS

The influence of organ dysfunction and atherosclerosis on the long-term survival of 338 consecutive patients undergoing successful elective AAA repair between 1980 and 1997 was analysed using Cox hazards model. Survival rate was compared with that of 349 patients undergoing successful revascularization for aortoiliac occlusive disease (AIOD) during the same interval.

RESULTS

Renal dysfunction and a previous history of cerebrovascular events were important variables predicting late death (risk ratio 1.980 and 1.903 respectively), while a history of cardiac disease predicted only cardiac-related death. The survival rate in patients with normal renal function was significantly better than that in those with renal dysfunction (P = 0.0371). Similarly, the survival rate was significantly better in patients without a history of previous cerebrovascular events (P = 0.0414). The survival rate after AAA repair was nearly identical to that of age- and sex-matched patients with grade II or III symptoms who had surgery for AIOD.

CONCLUSION

Advanced atherosclerosis with underlying organ dysfunction is a true determinant of long-term survival following elective repair of AAA.

Should endovascular surgery lower the threshold for repair of abdominal aortic aneurysms?

PURPOSE

Because endovascular repair of abdominal aortic aneurysms (AAAs) is less invasive, some investigators have suggested that this increasingly popular technique should broaden the indications for elective AAA repair. The purpose of this study was to calculate quality-adjusted life expectancy rates after endovascular and open AAA repair and to estimate the optimal diameter for elective AAA repair in hypothetical cohorts of patients at average risk and at high risk.

METHODS

A Markov decision analysis model was used in this study. Assumptions were made on the basis of published reports and included the following: (1) the annual rupture rate is a continuous function of the AAA diameter (0% for <4 cm, 1% for 4.5 cm, 11% for 5.5 cm, and 26% for 6.5 cm); (2) the operative mortality rate is 1% for endovascular repair (excluding the risk of conversion to open repair) and 3.5% for open repair at age 70 years; and (3) immediate endovascular-to-open conversion risk is 5%, and late conversion rate is 1% per year. The main outcome measure in this study was the benefit of AAA repair in quality-adjusted life years (QALYs). The optimal threshold size (the AAA diameter at which elective repair maximizes benefit) was measured in centimeters.

RESULTS

The benefit of endovascular repair is consistently greater than that of open repair, but the additional benefit is small-0.1 to 0.4 QALYs. For men in average health with gradually enlarging AAAs with initial diameters of 4 cm, endovascular surgery reduces the optimal threshold diameter by very little: from 4.6 to 4.6 cm (no change) at age 60 years, from 4.8 to 4.7 cm at age 70 years, and from 5.1 to 4.9 cm at age 80 years. For older men in poor health, endovascular surgery reduces the optimal threshold diameter substantially (8.1 to 5.7 cm at age 80 years), but the benefit of repair in this population is small (0.2 QALYs).

CONCLUSION

For most patients, the indications for AAA repair are changed very little by the introduction of endovascular surgery. Only for older patients in poor health does endovascular surgery substantially lower the optimal threshold diameter for elective AAA repair.

Long term relative survival after surgery for abdominal aortic aneurysm in western Australia: population based study

OBJECTIVE

To determine the long term relative survival of all patients who had surgery for abdominal aortic aneurysm in Western Australia during 1985-94.

DESIGN

Population based study.

SETTING

Western Australia.

SUBJECTS

All patients who had had surgery for abdominal aortic aneurysm in Western Australia during 1985-94.

MAIN OUTCOME MEASURES

Morbidity and mortality data of patients admitted and surgically treated for abdominal aortic aneurysm in Western Australia during 1985-94. Elective, ruptured, and acute non-ruptured cases were analysed separately. Independent analyses for sex and patients aged 80 years or more were also undertaken. Postoperative (>30 days) relative survival was assessed against age and sex matched controls.

RESULTS

Overall, 1475 (1257 men, 218 women) cases were identified. The crude five year survival after elective surgery, including deaths within 30 days of surgery, was 79% for both men and women. When compared with a matched population the five year relative survival after elective surgery was 94.9% (95% confidence interval 89.9% to 99.9%) for men but only 88.0% (76.3% to 99.7%) for women. The five year relative survival of those aged 80 years and over was good: 116.6% (89.1% to 144.0%) compared with 92.4% (87.7% to 97.0%) for those under 80 years of age (men and women combined). Cardiovascular disease caused 57.8% of the 341 deaths after 30 days.

CONCLUSION

In a condition such as abdominal aortic aneurysm, which occurs in elderly patients, relative survival is more clinically meaningful than crude survival. The five year relative survival in cases of elective and ruptured abdominal aortic aneurysm was better in men than in women. This is probably because of greater comorbidity in women with abdominal aortic aneurysm and this deserves more attention in the future. The long term survival outcome in octogenarians supports surgery in selected cases.

Epidemiology and potential for prevention of abdominal aortic aneurysm

BACKGROUND

Ruptured abdominal aortic aneurysm (AAA) is a common cause of death which is preventable by elective repair of an asymptomatic AAA.

METHODS

The literature was reviewed with emphasis on epidemiological studies and population-based screening surveys.

RESULTS AND CONCLUSION

The prevalence of small AAA ranges between 3 and 8 per cent. The incidence of asymptomatic AAA seems to be increasing, although exact incidence estimates vary. The most important risk factors for AAA are male sex, age, family history and smoking. Hypertension is associated with a mildly increased risk, but diabetes is not associated with any increase. Primary prevention of AAA is not a realistic option. There is no evidence of an effective medical treatment to prevent growth of small AAAs, although trials with propranolol are under way. The only intervention to prevent death from aneurysm is elective repair of the asymptomatic lesion. Screening for asymptomatic AAA can reduce the incidence of rupture. However, further studies are needed to determine the cost effectiveness of screening compared with that of other health programmes.

The efficacy of transfemoral endovascular aneurysm management: a study on size changes of the abdominal aorta during mid-term follow-up

OBJECTIVES

The aim of this study was to assess efficacy of transfemoral endovascular aneurysm management (TEAM) during mid-term follow-up.

DESIGN

Prospective multicentre study.

MATERIALS AND METHODS

In 26 patients treated by a Tube Endograft, the pre- and postoperative contrast enhanced computed tomography (CT) images were reviewed in a blinded fashion. Aortic diameters were measured at the coeliac trunk, the inferior and superior aneurysm neck and the level of the maximal aneurysm size. The changes in diameter were related to the presence or absence of an endoleak.

RESULTS

The median follow-up was 12 months. In 10 patients an endoleak was found. Three endoleaks sealed spontaneously within 30 days after operation. All aneurysms with persistent endoleaks expanded, at a median rate of 0.30 mm per month. Four patients were converted between 9 and 14 months after TEAM. Aneurysms excluded by the endoprosthesis showed a median shrinkage of 0.41 mm per month. The inferior aneurysm neck demonstrated significant growth during follow-up, unrelated to endoleaks.

CONCLUSIONS

This study demonstrated the efficacy of TEAM in discontinuing the process of aneurysm expansion. Complete seal of the aneurysm sac after TEAM leads to shrinkage or arrest of growth of the aneurysm, while persistent endoleak is associated with progressive expansion.

Factors influencing the long-term results of abdominal aortic aneurysm repair

The incidence of late graft complications such as para-anastomotic aneurysms, aortoenteric fistulas and graft infections following abdominal aortic aneurysm (AAA) repair is a major determinant of its overall benefit, yet most published reports of AAA repair have concentrated almost exclusively on the early postoperative mortality and morbidity. Accurate knowledge regarding the incidence of late complications is essential to making any decision regarding the operative vs nonoperative management of AAAs. A similar analysis must be applied to endovascular repair of AAAs before this technique is accepted as an alternative method of treating AAAs. In this article we review the current knowledge and understanding on the late results following aortic aneurysm repair.

The influence of age on operative mortality and long-term relative survival following emergency abdominal aortic aneurysm operations

OBJECTIVE

To study operative mortality and long-term survival following emergency operations for abdominal aortic aneurysm.

DESIGN

Retrospective survey in a university hospital.

MATERIALS

Two hundred and twenty-seven patients with median age 72 years, (17% women).

METHODS

Founded on data from the Norwegian Registrar's Office, operative mortality and long-term survival was estimated using the life-table method. Expected survival for demographically matched subgroups was calculated from death rate tables issued by the Norwegian Central Bureau of Statistics.

RESULTS

Operative mortality was 41% for the 175 patients with ruptured aneurysms and 17% for the 52 with imminent rupture. The 6-year survival rate was 61% for all the successfully operated patients, and not different from that of a demographically matched population. For the patients of 72 years or older the 6-year survival rate was 53%. This was equal to that of an age and sex matched population. The younger patients had an observed 6-year survival rate of 64%, which was significantly lower than the expected of 84%. The standard mortality rate for this group was 2.25. No statistically significant difference in long-term survival was detected between the two age groups.

CONCLUSIONS

Age at the time of the operation for a symptomatic abdominal aortic aneurysm does not seem to influence long-term survival. Consequently, younger patients experience a higher relative mortality compared to the older.