Abdominal aortic aneurysm in Scotland

A REVIEW OF THE MECHANICAL STRESSES PREDISPOSING ABDOMINAL AORTIC ANEURYSMAL RUPTURE: UNIAXIAL EXPERIMENTAL APPROACH

In this paper, problems concerning the uniaxial experimental investigation of the human abdominal aortic aneurysm (AAA) biomechanical characteristics, concomitant values of the associated Cauchy stress, failure (ultimate) stress in AAA, and the constitutive modeling of AAA are considered. The aim of this paper is to review and compare the disposable experimental data, to reveal the reasons for the high dissipation of the results between studies, and to propound some unification criteria. We examined 22 literature sources published between 1994 and 2017 and compared their results, including our own results. The experiments in the reviewed literature have been designed to obtain the stress–strain characteristics and the failure (ultimate) stress and strain of the aneurysmal tissue. A variety of forms of the strain–energy function (SEF) have been applied in the considered studies to model the biomechanical behavior of the aneurysmal wall. The specimen condition and physical parameters, the experimental protocols, the failure stress and strain, and SEFs differ between studies, contributing to the differences between the final results. We propound some criteria and suggestions for the unification of the experiments leading to the comparable results.

A Karnaugh map based approach towards systemic reviews and meta-analysis

Studying meta-analysis and systemic reviews since long had helped us conclude numerous parallel or conflicting studies. Existing studies are presented in tabulated forms which contain appropriate information for specific cases yet it is difficult to visualize. On meta-analysis of data, this can lead to absorption and subsumption errors henceforth having undesirable potential of consecutive misunderstandings in social and operational methodologies. The purpose of this study is to investigate an alternate forum for meta-data presentation that relies on humans’ strong pictorial perception capability. Analysis of big-data is assumed to be a complex and daunting task often reserved on the computational powers of machines yet there exist mapping tools which can analyze such data in a hand-handled manner. Data analysis on such scale can benefit from the use of statistical tools like Karnaugh maps where all studies can be put together on a graph based mapping. Such a formulation can lead to more control in observing patterns of research community and analyzing further for uncertainty and reliability metrics. We present a methodological process of converting a well-established study in Health care to its equaling binary representation followed by furnishing values on to a Karnaugh Map. The data used for the studies presented herein is from Burns et al (J Publ Health 34(1):138–148, 2011) consisting of retrospectively collected data sets from various studies on clinical coding data accuracy. Using a customized filtration process, a total of 25 studies were selected for review with no, partial, or complete knowledge of six independent variables thus forming 64 independent cells on a Karnaugh map. The study concluded that this pictorial graphing as expected had helped in simplifying the overview of meta-analysis and systemic reviews.

Systematic review of discharge coding accuracy

INTRODUCTION

Routinely collected data sets are increasingly used for research, financial reimbursement and health service planning. High quality data are necessary for reliable analysis. This study aims to assess the published accuracy of routinely collected data sets in Great Britain.

METHODS

Systematic searches of the EMBASE, PUBMED, OVID and Cochrane databases were performed from 1989 to present using defined search terms. Included studies were those that compared routinely collected data sets with case or operative note review and those that compared routinely collected data with clinical registries.

RESULTS

Thirty-two studies were included. Twenty-five studies compared routinely collected data with case or operation notes. Seven studies compared routinely collected data with clinical registries. The overall median accuracy (routinely collected data sets versus case notes) was 83.2% (IQR: 67.3-92.1%). The median diagnostic accuracy was 80.3% (IQR: 63.3-94.1%) with a median procedure accuracy of 84.2% (IQR: 68.7-88.7%). There was considerable variation in accuracy rates between studies (50.5-97.8%). Since the 2002 introduction of Payment by Results, accuracy has improved in some respects, for example primary diagnoses accuracy has improved from 73.8% (IQR: 59.3-92.1%) to 96.0% (IQR: 89.3-96.3), P= 0.020.

CONCLUSION

Accuracy rates are improving. Current levels of reported accuracy suggest that routinely collected data are sufficiently robust to support their use for research and managerial decision-making.

Outcome from abdominal aortic aneurysms in Scotland, 1991-2006

BACKGROUND

This study assessed the impact of sex, presentation and treatment on outcome from abdominal aortic aneurysm (AAA) in Scotland.

METHODS

All patients admitted from January 1991 to December 2006 with a primary diagnosis of AAA were identified. Patients were stratified by age, sex, admission diagnosis (ruptured versus intact) and procedure performed (endovascular versus open repair). Multivariable logistic regression analysis was used to determine predictors of mortality.

RESULTS

Some 9779 men and 2927 women were admitted with a principal diagnosis of AAA. Women were significantly older than men (median (range) age 75 (35-97) versus 71 (17-96) years; P < 0.001). A higher proportion of women presented with a ruptured AAA (29.5 versus 27.5 per cent; P = 0.043). Age (odds ratio (OR) 2.52 (95 per cent confidence interval 2.36 to 2.74); P < 0.001), female sex (OR 1.63 (1.48 to 1.78); P < 0.001) and admission diagnosis (OR 10.49 (9.53 to 11.54); P < 0.001) were independent predictors of early death, whereas endovascular repair predicted survival (OR 0.67 (0.58 to 0.76); P < 0.001).

CONCLUSION

Women presenting with an AAA were older and more likely to be admitted with a ruptured aneurysm. Female sex was an independent risk factor for death from AAA.

Endovascular abdominal aortic aneurysm repair

The operative mortality following conventional abdominal aortic aneurysm (AAA) repair has not fallen significantly over the past two decades. Since its inception in 1991, endovascular aneurysm repair (EVAR) has provided an alternative to open AAA repair and perhaps an opportunity to improve operative mortality. Two recent large randomised trials have demonstrated the short and medium term benefit of EVAR over open AAA repair, although data on the long term efficacy of the technique are still lacking. This review aimed at providing an overview of EVAR and a discussion of the potential benefits and current limitations of the technique.

Indications for operative management of abdominal aortic aneurysms

The increasing incidence of abdominal aortic aneurysms, along with the more frequent use of screening techniques, has resulted in greater numbers of patients with small abdominal aortic aneurysms. The questions of frequency of surveillance and timing of intervention are the two most controversial issues faced by surgeons dealing with this condition. Most management decisions are based on the size of the aneurysm but other factors must also be considered. This review makes recommendations on the management of small abdominal aortic aneurysms according to the current available evidence.

Persistent increase in the incidence of abdominal aortic aneurysm in Scotland, 1981–2000

Background

In the 1970s and 1980s, mortality and morbidity rates for abdominal aortic aneurysm (AAA) increased throughout the developed world. As AAAs are associated with similar risk factors to other cardiovascular diseases that have recently decreased in incidence, the incidence of AAA should show a similar declining trend.

Methods

Routinely collected data were obtained on all primary diagnoses of aortic aneurysm resulting in death or hospital discharge in Scotland between 1981 and 2000. Trends in the data were analysed according to sex and age, aneurysm site and type of hospital admission.

Results

Between 1981 and 2000, 42·3 per cent of the 10 822 deaths from aortic aneurysm in Scotland were attributed to the abdominal aorta. Age-adjusted mortality rates for AAA increased 2·6-fold from 2·62 deaths per 100 000 in 1981 to 6·82 per 100 000 in 2000. Hospital admissions for AAA also rose threefold, with increases in both elective admissions (from 3·05 to 7·80 per 100 000) and emergency admissions (from 7·44 to 11·23 per 100 000).

Conclusion

The incidence of AAA has increased over the past 20 years in Scotland. This is unlikely to be due simply to changes in detection and diagnosis, data inaccuracies, coding or ageing of the population. The incidence of both elective and emergency admission for AAA increased, suggesting that a genuine and persistent rise in the incidence of AAA has probably occurred.

Abdominal aortic aneurysms in the New Zealand Maori population

BACKGROUND

Abdominal aortic aneurysm (AAA) is believed to be a rare disease in people of non-European descent. Maori, New Zealand's indigenous people, are thought to originate from South East Asia, so their incidence of AAA might also be expected to be low. The aim was to investigate the incidence and phenotypic factors associated with AAA in the New Zealand Maori population.

METHODS

A retrospective study was performed using the audit database of the New Zealand Society of Vascular Surgeons. Age-standardized rates of admission and death were calculated for Maori and non-Maori.

RESULTS

Maori comprised 3.9 per cent of the population who had an AAA repaired, similar to the percentage of the Maori population aged over 65 years. However, the death rate from AAA in Maori was 2.4 times the rate in non-Maori. Maori were younger at diagnosis than non-Maori (65.2 versus 71.8 years; P < 0.001), had more emergency procedures (46.6 versus 30.2 per cent; P = 0.018) and a significantly higher proportion of Maori admissions were for a ruptured aneurysm.

CONCLUSION

Maori had a higher mortality rate from AAA than non-Maori New Zealanders. Although admission rates between Maori and non-Maori were similar, the earlier age of onset and the increased proportion of ruptured aneurysms may indicate that the disease is more severe in Maori.

Initial experience of abdominal aortic aneurysm repairs in Borneo

BACKGROUND

Abdominal aortic aneurysms (AAA) repairs are routine operations with low mortality in the developed world. There are few studies on the operative management of AAA in the Asian population.This study reports the initial results from a unit with no previous experience in this surgery by a single surgeon on completion of training.

METHODS

All patients with AAA repair from a prospective database between 1996 and 1999 in the south-east Asian state of Sarawak in Borneo Island were analyzed. Three groups were identified on presentation according to clinical urgency of surgery. Elective surgery was offered to all good risk patients with AAA of >or= 5 cm. All symptomatic patients were offered surgery unless contraindicated medically.

RESULTS

AAA repairs were performed in 69 patients: 32 (46%)had elective repairs of asymptomatic AAA; 20 (29%) had urgent surgery for symptomatic non-ruptured AAA; and 17 (25%)had surgery for ruptured AAA. The mortality rate for elective surgery was 6%; the two deaths occurred early in the series with the subsequent 25 repairs recorded no further mortality. The mortality rates for the urgent, symptomatic non-ruptured AAA repair and ruptured AAA repair were 20% and 35%, respectively. Cardiac and respiratory complications were the main morbidities.Sixty-three patients seen during this period had no surgery; three presented and died of ruptured AAA, 34 had AAA of <or= 5 c min diameter, and 26 with AAA of >or= 5 cm diameter had either no consent for surgery or serious medical contraindications.

CONCLUSION

This study showed that AAA can be repaired safely by highly motivated and adequately trained surgeons in a hospital with little previous experience.

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.

Literature review of surgical management of abdominal aortic aneurysm

OBJECTIVES

To review the natural history and the outcome of surgical repair of aortic abdominal aneurysm (AAA).

DESIGN

An English and Scandinavian language search of papers between 1985-1997.

RESULTS

After review, 132 papers with 54 048 patients remained. The mean postoperative mortality (30 days or in-hospital) for elective repair was approximately 5% and for emergency operations 47% (range 27-69%), both with significant heterogeneity. Results did not improve over time. Increasing age, presence of renal failure and atherosclerotic cardiac disease were identified as pre-operative risk factors. AAA expansion averaged 0.2-0.4 cm per year for aneurysms smaller than 4 cm, 0.2-0.5 cm for aneurysms 4-5 cm and 0.3-0.7 cm for those larger than 5 cm. The rupture risk at four years was 2, 10 and 22% respectively. The overview revealed several methodological problems in the reported studies.

CONCLUSIONS

The results can be used as the basis of quality assurance or in decision trees or other models. Better reporting standards are needed.

Peroperative factors influencing the outcome of elective abdominal aorta aneurysm repair

PURPOSE

To identify perioperative variables which may influence mortality of elective abdominal aneurysm repair (AAA).

METHOD

prospective study of patients undergoing elective AAA repair between 1986 and 1997.

RESULTS

Four hundred and seventy patients (438 men, 32 females) with a mean age of 69.4+/-13 years and aneurysms with a diameter of 60+/-3 mm were operated on with a 1-month mortality rate of 5.3%. Multivariate analysis identified the following independent risk factors for mortality: age >70 (p<0.0001), a past history of myocardial infarction (p<0.0001), preoperative renal insufficiency (p<0.0001), reoperation (p<0.0001), colonic necrosis (p<0.0001), and severe postoperative medical complications (p<0.0001).

CONCLUSION

Intra- and postoperative events affect the outcome of AAA repair, independently of preoperative factors, and should be described when presenting the results of AAA repair.

A 14-year experience with 6 cm as a criterion for surgical treatment of abdominal aortic aneurysm

BACKGROUND

It remains unclear when to recommend operation for an asymptomatic abdominal aortic aneurysm (AAA). This study examined a prospective series of patients for whom standard criteria were applied.

METHODS

Some 584 consecutive patients with an AAA of diameter 3 cm or greater detected by ultrasonographic screening have been observed for up to 14 years. Repeat ultrasonographic examinations have been performed at intervals. Surgery was not considered unless the aneurysm measured 6 cm in diameter, expanded at a rate equivalent to at least 1 cm per year, caused the patient symptoms, or an iliac aneurysm was present that required treatment.

RESULTS

Operation was performed on 127 patients; the majority (80; 63 per cent) had an aneurysm that reached 6 cm in diameter. Use of the above criteria prevented rupture in all but 24 (4 per cent) of the 584 patients over the 14-year interval. Of these 24 patients, 11 were unfit for planned surgery and eight declined operation or follow-up. Rupture in the five remaining patients (1 per cent) who were available for treatment compared favourably with the reported 30-day mortality rate for elective surgical treatment of 1.4-12 per cent.

CONCLUSION

Repeated observation is preferable to surgical intervention until an aortic aneurysm measures 6 cm in diameter, expands by 1 cm per annum or causes symptoms. Presented as a poster to the 52nd Annual Meeting of the Society for Vascular Surgery, San Diego, California, USA, June 1998

Influence of study design on reported mortality and morbidity rates after abdominal aortic aneurysm repair

BACKGROUND

The mortality and morbidity rates of elective abdominal aortic aneurysm (AAA) surgery, as reported over the past 12 years, were graded and analysed by levels of evidence.

METHODS

Articles on elective AAA surgery published between 1985 and 1996 were retrieved and classified into five levels of evidence. Level 1 contains prospective studies and is subdivided into population-based (level 1a) and hospital-based (level 1b) studies. Level 2 includes retrospective studies, subdivided into population-based studies (level 2a), hospital-based studies (level 2b) and hospital-based studies concerning a specified group of selected patients (level 2c). Operative mortality and systemic and local/vascular complication rates with 95 per cent confidence intervals were calculated for each level of evidence.

RESULTS

Seventy-two articles describing a total of 37 654 patients could be included: two level 1a studies (692 patients), nine level 1b studies (1677 patients), 13 level 2a studies (21 409 patients), 32 level 2b studies (12019 patients) and 16 level 2c studies (1857 patients). The mean 30-day mortality rates of the two population-based levels were similar: 8.2 (95 per cent confidence interval 6.4-10.6) per cent for the prospective (la) and 7.4 (7.0-7.7) per cent for the retrospective (2a) series. These figures were significantly higher than the remarkably similar hospital-based mortality rates: 3.8 (3.0-4.8) per cent for the prospective (1b), 3.8 (3.5-4.2) per cent for the retrospective (2b) and 3.5 (2.8-4.4) per cent for selected patient group (2c) studies. The most frequent complication was of cardiac origin. In the population-based series the cardiac complication rates were 10.6 (8.5-13.2) and 11.1 (9.1-13.6) per cent for levels 1a and 2a respectively. This compared well with 12.0 (10.5-13.9) per cent for the prospective hospital-based series (level 1b). The cardiac complication rates in the retrospective hospital-based studies were significantly lower: 8.9 (8.4-9.5) and 6.1 (4.9-7.6) per cent for levels 2b and 2c respectively.

CONCLUSION

There is a clear and consistent disagreement in reported mortality rates between hospital-based and population-based studies of elective surgery for AAA. Prospective studies give the best documentation of postoperative morbidity.

The Quality of Surgical Care Project: benchmark standards of open resection for abdominal aortic aneurysm in Western Australia

BACKGROUND

The Quality of Surgical Care Project (QSCP) was established in May 1996, to evaluate surgical outcomes and where indicated, recommend changes to improve the quality of surgical care in Western Australia (WA). The purpose of this study is to establish benchmark standards in WA for operative mortality, 5-year survival and length of stay in all patients who were surgically treated for aneurysm of the abdominal aorta (AAA) in WA.

METHODS

The WA Linked Database was used to link the morbidity and mortality records of all patients admitted and surgically treated for AAA in WA from 1985 to 1994. The linked chains of de-identified hospital morbidity and death records were selected using diagnostic and procedure codes pertaining to AAA. Three groups were separated for analysis: those admitted for rupture, those admitted for elective repair, and those who were admitted to hospital as an emergency without mention of rupture but who underwent repair for AAA. Independent analysis for gender and patients 80 years or more were included in the study. Patients were excluded from the study if they were less than 55 years of age.

RESULTS

A total of 1475 cases (1257 males, 218 females) were identified. The mean age in elective cases was 70.4 years in males and 72.4 years in females, and for rupture the mean ages were 71.9 and 74.8 years, respectively. Median length of stay for males was 12 days for elective cases. Admission type or age did not significantly influence length of stay. Thirty-day mortality in males was 4.4% for elective repair and 36.7% for ruptured AAA and 5-year survival was 71.7 and 47.7%, respectively. The overall case fatality rate for ruptured AAA was 79.3% which included those cases who died from rupture without being admitted to hospital.

CONCLUSIONS

These community-wide data provide a realistic measure of surgical performance for open repair of AAA. The outcomes for elective and rupture repair for AAA compare favourably with standards reported by international centres of excellence. They also support the use of this procedure in patients over 80 years of age with rupture. This information can be used for ongoing audit purposes and as a benchmark for the introduction of new treatment modalities.

A 21-year experience of abdominal aortic aneurysm operations in Edinburgh

BACKGROUND

This study reviews the results of infrarenal abdominal aortic aneurysm (AAA) surgery over 21 years (1 January 1976 to 31 December 1996).

METHODS

A prospectively gathered database was analysed.

RESULTS

Infrarenal AAA repair was performed in 1515 patients: 492 (32.5 per cent) had elective repair of an asymptomatic AAA; 194 (12.8 per cent) had elective repair of a symptomatic AAA; 156 (10.3 per cent) had emergency repair of a symptomatic non-ruptured AAA; and 673 (44.4 per cent) had surgery for a ruptured AAA. The 30-day and/or same admission mortality rates were 6.1, 5.8, 14.1 and 37 per cent respectively. Operative mortality increased in all four groups over the study interval, although this only attained statistical significance in patients having elective repair of a symptomatic, non-ruptured AAA. There was a significant increase in the age of patients undergoing elective repair of an asymptomatic AAA, but not in the other three groups. There was also a significant increase in the proportion of straight 'tube' grafts inserted in all four groups.

CONCLUSIONS

It remains the minority of patients who have elective operation before the onset of symptoms and/or rupture. Despite anaesthetic and surgical specialization, the results of AAA repair have not improved over the past two decades. Operative mortality may be increasing, possibly because of the increasing age and associated comorbidity of the patients presenting to this unit.

Population-based record linkage study of the incidence of abdominal aortic aneurysm in Western Australia in 1985-1994

BACKGROUND

The incidence of abdominal aortic aneurysm (AAA) has increased steadily during the past 30 years.

METHODS

Trends in the incidence and surgical intervention for AAA in Western Australia were reviewed for the interval 1985-1994. A population-based health database was used to link morbidity and mortality records of all patients aged 55 years or more who died from rupture or were admitted and treated surgically for AAA. Three groups were separated for analysis: patients with a ruptured AAA, those admitted for elective repair and those admitted as an emergency with an acute (non-ruptured) aneurysm.

RESULTS

There was a decline in the incidence of both emergency and elective procedures for AAA after 1992. While the mortality rate from ruptured AAA has also fallen since 1991, the overall case fatality rate for ruptured AAA has fallen by only 1.3 per cent (from 80.7 to 79.3 per cent).

CONCLUSION

The decline in mortality rate and emergency procedures may result from a fall in the incidence of ruptured AAA, due to an increasing rate of elective surgery before 1992. The decline in elective procedures from 1992 may be due to a fall in the prevalence of AAA owing to high rates of elective surgery, or to a fall in the incidence of the disease itself.

Long-term survival and late complications after repair of ruptured abdominal aortic aneurysms

PURPOSE

Long-term survival and late vascular complications in patients who survived repair of ruptured abdominal aortic aneurysms (RAAA) is not well known. The current study compared late outcome after repair of RAAA with those observed in patients who survived elective repair of abdominal aortic aneurysms (AAA).

METHODS

The records of 116 patients, 102 men and 14 women (mean age: 72.5 (8.3 years), who survived repair of RAAA (group I) between 1980 to 1989 were reviewed. Late vascular complications and survival were compared with an equal number of survivors of elective AAA repair matched for sex, age, surgeon, and date of operation (group II). Survival was also compared with the age and sex-matched white population of west-north central United States.

RESULTS

Late vascular complications occurred in 17% (20/116) of patients in group I and in 8% (9/116) in group II. Paraanastomotic aneurysms occurred more frequently in group I than in group II (17 vs. 8, p = 0.004). At follow-up, 32 patients (28%) were alive in group I (median survival: 9.4 years) and 53 patients (46%) were alive in group II (median survival: 8.7 years). Cumulative survival rates after successful RAAA repair at 1, 5, and 10 years were 86%, 64%, and 33%, respectively. These were significantly lower than survival rates at the same intervals after elective repair (97%, 74%, and 43%, respectively, p = 0.02) or survival of the general population (95%, 75%, and 52%, respectively, p < 0.001). Coronary artery disease was the most frequent cause of late death in both groups. Vascular and graft-related complications caused death in 3% (3/116) in group I and 1% (1/116) in group II. Cox proportional hazards modeling identified age (p = 0.0001), cerebrovascular disease (p = 0.009), and number of days on mechanical ventilation (p = 0.01) to be independent prognostic determinants of late survival in group I.

CONCLUSIONS

Late vascular complications after repair of RAAA were higher and late survival rates lower than after elective repair. These data support elective repair of AAA. As two-thirds of the patients discharged after repair of RAAA are alive at 5 years, aggressive management of RAAA remains justified.

Expansion rates of abdominal aortic aneurysm: current limitations in evaluation

OBJECTIVES

Literature on the expansion rate of infrarenal aortic aneurysm is scant. This review was carried out to assess whether there is a normal rate of expansion for infrarenal aortic aneurysms.

DESIGN AND METHODS

Review of literature relating to abdominal aortic aneurysm (AAA) measurement and expansion rates. Articles were identified from a search of the computerised Medline database from 1966 onwards.

RESULTS

Nine studies produced expansion rates for 3.0-5.0 cm AAA ranging from 0.17 to 0.57 cm per year. Evaluation of these studies showed that they are not wholly comparable in terms of source population, sample size, disease definition and period of assessment.

CONCLUSIONS

It is not possible to discuss with confidence the "normal" expansion rate of infrarenal aortic aneurysms at any diameter. To elucidate fully the behaviour of AAA, a clear and universal definition of AAA is required in order that it may be used within a large, multicentered prospective cohort study.

Surgical management of 671 abdominal aortic aneurysms: a 13 year review from a single centre

OBJECTIVE

To audit the results for abdominal aortic aneurysm (AAA) repair from a single centre over a 13 year period.

DESIGN

Retrospective survey.

SETTING

Vascular unit of a major teaching hospital.

MATERIALS

Six hundred and seventy-one consecutive patients divided into two groups: group A (1981-87) and group B (1988-93).

CHIEF OUTCOME MEASURES

Mortality rates, cause of death and major complications in patients undergoing elective, urgent and ruptured AAAs.

RESULTS

Elective repair was performed in 313 (47%) patients, urgent repair in 80 (12%) and emergency repair for rupture in 278 (41%). A vascular surgeon performed the procedure in 94% of patients. The overall mortality was 21 patients in the elective group (6.7%), 13 in the urgent group (16%) and 148 in the ruptured group (53%). Mortality rates have not fallen during the study period but more patients in group B had ischaemic heart disease. Sixty patients (9%) required further operative procedures on 66 occasions: 24 elective cases (8%), 8 urgent cases (10%) and 28 ruptured cases (10%). There were 23 deaths in these 60 patients (38%) who underwent re-operation (5 elective, 2 urgent and 16 ruptured). Major postoperative complications included cardiac events in 212 (32%) patients, respiratory failure in 202 (30%) and renal failure in 90 (13%). Major causes of death included cardiac disease in 67 patients (37%), cardiac disease with coagulopathy in 22 (12%) and cardiac disease with respiratory failure in 16 (9%). Logistic regression analysis showed that in the elective group, cardiac or renal failure were significantly associated with death; and in the ruptured group cardiac, respiratory or renal failure were significantly associated with death.

CONCLUSIONS

More high risk patients with ischaemic heart disease are undergoing AAA repair. Postoperative cardiac, respiratory or renal failure are significant causes of death in AAA patients.

Risk factors for abdominal aortic aneurysms in older adults enrolled in The Cardiovascular Health Study

B-mode ultrasound examinations of the abdominal aorta were performed from 1990 to 1992 to evaluate the prevalence of abdominal aortic aneurysm (AAA) in a subgroup of the Pittsburgh cohort (656 participants, aged 65 to 90 years) of the Cardiovascular Health Study (CHS). In this pilot study, we evaluated various definitions of aneurysm and the reproducibility of the measurements. In year 5 (1992 to 1993) of the CHS, the entire cohort (4741 participants) was examined. AAA was defined as an infrarenal aortic diameter of > or= 3.0 cm, or a ratio of infrarenal to suprarenal diameter of > or= 1.2, or a history of AAA repair. For the entire CHS cohort, prevalence of aneurysms was 9.5% (451/4741) overall, with a prevalence among men of 14.2% (278/1956) and prevalence among women of 6.2% (173/2785). Variables significantly related to AAA were older age; male sex; history of angina, coronary heart disease, and myocardial infarction; lower ankle-arm blood pressure ratio; higher maximum carotid stenosis; greater intima-media thickness of the internal carotid artery; higher creatinine; lower HDL levels and higher LDL levels; and cigarette smoking. The study has documented the strong association of cardiovascular risk factors and measures of clinical and subclinical atherosclerosis and cardiovascular disease and prevalence of aneurysms. We used a definition that is more sensitive than previously reported (diameter or ratio), which allowed the detection of smaller aneurysms and possibly those at an earlier stage of development. Follow-up of this cohort may lead to new criteria for determining the risk factors for progression of aneurysms.

Incisional hernias are more common in aneurysmal arterial disease

OBJECTIVE

To test the hypothesis that incisional hernia was a more frequent complication following aortic reconstructive surgery in patients with aneurysmal as opposed to occlusive aortic disease.

DESIGN

A retrospective review.

MATERIALS AND METHODS

All patients having aortic reconstructive surgery at a teaching hospital between 1988 and 1992 were identified and recalled to be examined for evidence of an incisional hernia.

RESULTS

Of the 134 patients having aortic reconstructive surgery, 87 were available to be examined by an independent clinician. The overall incisional hernia rate was 28%. Patients with aneurysmal disease were significantly more likely to develop an incisional hernia after elective surgery than patients with occlusive disease (p = 0.04). None of the other variables investigated, including age, chronic obstructive airways disease, diabetes, smoking, wound infection, obesity, length of intensive care unit stay and number of units of blood transfused, were significantly related to the complication of incisional hernia.

CONCLUSION

Incisional hernia is a common complication of aortic reconstructive surgery, especially in patients with aneurysmal disease.

Co-morbidity in patients with abdominal aortic aneurysm

OBJECTIVES

Selection for surgery of patients with abdominal aortic aneurysm (AAA) depends on an assessment of risk from operation compared with risk from aneurysm rupture. A study was performed to assess the levels of co-morbidity and to see whether co-morbidity was different in people with a normal aorta after ultrasonographic examination than in those with an aneurysmal aorta.

SETTING AND METHODS

Over a two year period 5392 people (2341 men, 3051 women) aged 65-80 were screened using B-mode linear ultrasound, with maximum measurements taken of transverse, anteroposterior diameters, or both. All subjects were given a questionnaire seeking a history of angina, stroke, claudication, myocardial infarct, respiratory problems, and diabetes.

RESULTS

218 men and women were found to have an AAA of 3 cm or greater. The results of the questionnaire were analysed using logistic regression whereby all the co-morbid conditions were adjusted for each other and for smoking, sex, and age. The only conditions which were significantly associated with AAA in both sexes were myocardial infarction with an odds ratio (OR) of 1.66 (95% confidence interval (CI) 1.06 to 2.60) and claudication with an OR of 1.68 (95% CI 1.17 to 2.42). The association between angina and AAA was of borderline significance (OR = 1.52, 95% CI 1.00 to 2.30). Stroke was significantly associated only in women, with an OR of 3.71 (95% CI 1.42 to 9.69). Rates of diabetes and respiratory disease were not significantly different between people with AAA and normal aortas.

CONCLUSIONS

These findings show there is significantly higher co-morbidity in people with ultrasound detected AAA, which might influence outcome from surgery and long term survival.

Prospective audit of abdominal aortic aneurysm surgery in the northern region from 1988 to 1992. Northern Vascular Surgeons Group

Over a 5-year period a prospective audit was carried out on 1131 patients undergoing surgery for abdominal aortic aneurysm (AAA) in the northern region. A total of 470 operations was performed in teaching hospitals and 661 in district hospitals; emergency operations accounted for 41.5 per cent. The overall mortality rate was 25.8 per cent; for emergency cases this value was 50.0 per cent. Mortality rates for elective surgery were 3.9 per cent in teaching and 12.0 per cent in district hospitals. Patients with ruptured AAA admitted via the accident and emergency department had a higher mortality rate (64.3 per cent) than those admitted by their general practitioner (49.5 per cent) or those referred from the urology department (18.8 per cent). In all, 73 (6.5 per cent) patients were admitted with an alternative diagnosis, ranging from collapse of unknown cause (25) to torsion of the testes (one) and colonic obstruction (one). Age had a profound effect on mortality rates. For emergency cases the mortality rate varied from 47.0 per cent (in teaching plus district hospitals) in those aged less than 80 years to 70.1 per cent in those 80 years or over (chi 2 = 7.22; P = 0.007). For elective surgery the mortality rate varied from 7.6 per cent (in teaching plus district hospitals) in those under 80 years to 23.8 per cent in those 80 years or over (P = 0.0006). The overall mortality rate of 25.8 per cent is significantly less than that quoted in the Confidential Enquiry into Perioperative Deaths report of 1987. Furthermore, elective patients over 80 years of age may expect a survival rate of 76 per cent and, in the absence of major medical contraindications, should not automatically be denied surgery. Importantly, it is of note that this prospective audit identified 31 per cent more cases than recognized by regional audit data.