Abdominal aortic aneurysm. Change in diagnosis and therapy

The improved diagnostic approach using computerised tomography and ultrasound investigation resulted recently in a remarkable increase of early diagnosed abdominal aortic aneurysm. Simultaneously in the last decennium the number of elective interventions has been increased 4-6 times. As a result of simplification and standardisation of the operative technique (dissection resp. inlay-technique) the operative mortality for elective surgery has decreased to 1-3%. Statistical datas proved a significant increase of life expectancy for operated patients. Interventions for ruptured abdominal aortic aneurysms are still loaded with a high risk (mortality rate 40-75%). Both elective and emergency vascular repairs should be done by well trained vascular surgeons and should not be a challenge for general surgeons to do sporadic vascular surgery.     

Abdominal aortic aneurysms. Is there an association between surgical volume, surgical experience, hospital type and operative mortality? Members of the Norwegian Abdominal Aortic Aneurysm Trial

The effects of number of operations, experience of the surgeon, and type of hospital on operative mortality have been studied in 444 patients treated for abdominal aortic aneurysms. In the elective group (n = 279) there was a significant difference in mortality between hospitals in which more than 10 such operations were done compared with those in which less than 10 were done during the study period (p = 0.05; odds ratio (OR) 2.7). In the ruptured group there was no statistically significant difference (p = 0.14; OR 1.9). In the elective group, units with vascular surgical experience had an operative mortality of 4.8% compared with 11.3% for other units (p = 0.05; OR 2.6). In the ruptured group the figures were 52.5% and 73.3% respectively (p = 0.03; OR 2.5). There was no difference in operative mortality between university, county and local hospitals. Outcome of treatment after operations for abdominal aortic aneurysm was related to number of operations carried out and experience, whereas the type of hospital seemed less important.     

Is there a minimum caseload that achieves acceptable operative mortality in abdominal aortic aneurysm operations?

BACKGROUND: Studies have shown correlation between operative workload and mortality for major operations. Is there a threshold for case volume that predicts an acceptable mortality for abdominal aortic aneurysm surgery? METHODS: Hospital Episode Statistics (HES) Data for England between 1997-2002 was analysed using ICD-10 codes I71.x and OPCS-4 codes L16.x-L26.x. Mortality was identified by the method of discharge. RESULTS: 31,078 operations on abdominal aortic aneurysms were studied in 223 NHS Trusts. 6,007 in-hospital deaths were identified in both elective and emergency cases (overall mortality rates 7.7% and 40%, respectively). Trusts with large elective workloads had reduced mortality for both elective and emergency operations. Using parabolic regression and logarithmic transformation, 14 elective operations per Trust per year was identified as a cut-off point above which the decrease in mortality rate with increasing case volume was relatively small. A similar effect was not seen with increasing emergency workload alone. CONCLUSION: HES data analysis suggests increasing elective workload correlates with lower in-hospital mortality for elective and emergency operations on abdominal aortic aneurysm. Data suggests a range of hospital caseload that correlate with an acceptable elective and emergency mortality rate.     

Trends in abdominal aortic aneurysm surgery in Scotland (1971-1984)

The trends in diagnosis, operative workload and mortality of patients with abdominal aortic aneurysm in Scottish hospitals between 1971 and 1984 were analysed using the Scottish Hospital In-patient Statistics. The frequency of diagnosis of aneurysm increased from 25.8 per 100,000 population aged over 55 in 1971 to 63.6 per 100,000 in 1984. The proportion of diagnosed aneurysms treated by operation rose from 24% in 1971 to 41% in 1984, resulting in a 4-fold increase in operative workload. Despite the rise in diagnosis of abdominal aortic aneurysm, the ratio of elective to emergency procedures has only improved slightly during the 14 years, the majority still being operated on as emergencies. The operative mortality following elective procedures fell from 10.5% in 1971 to 4.3% in 1984, while that for emergencies fell from 50% to 36%. The reasons for the increased surgical workload are multifactorial. It is not solely a consequence of an ageing population as the proportion of Scots aged over 55 years increased by only 4% during this period. The evidence from this study suggests that the rise in workload is secondary to an increase in the frequency of diagnosis of abdominal aortic aneurysm in all age groups and to the fact that a greater proportion of diagnosed cases are now offered surgery.     

The epidemiology of surgically repaired aneurysms in the United States.

OBJECTIVE: The purpose of this study was to determine the results of surgery for hospitalized cases of aneurysms in the United States, thereby providing a standard of comparison for new techniques proposed to treat aneurysms. METHODS: Data on hospitalized aneurysm cases were collected from the National Hospital Discharge Survey, a comprehensive database of patients hospitalized in the United States for treatment from the years 1984 to 1994. The National Hospital Discharge Survey samples non-federal, acute-care hospitals with an average length of stay of less than 30 days. All the cases had a diagnosis of or a surgical procedure for a non-cerebral aneurysm. RESULTS: In the year 1994, 51,949 non-cerebral aneurysms were repaired in the United States, and 75% of these procedures were abdominal aortic aneurysm (AAA) surgeries. The operative mortality rates for AAA were higher than previously reported from multi-institutional studies and were found to be 8.4% for elective repair and 68% for emergency AAA repair. The number of aneurysm surgeries per thousand population varied by region: surgery rates were more frequent in the Northeast and less frequent in the West. Surgical volume appeared to decrease for smaller hospitals and increase for larger hospitals for the period between 1990 and 1994. The overall mortality rates for all aneurysm surgeries diminished with hospital size. However, no significant difference was found for the rates of elective AAA repair between hospital sizes. The percentage of men with aneurysms who underwent surgery for repair was significantly higher than for women with aneurysms. In addition, the AAA repair rates increased for men from 1985 to 1994, and the number of women reported with repaired AAAs remained constant. CONCLUSION: The location of aneurysm, urgency of repair, region, sex, and hospital size are important factors related to patient treatment and outcome. These data provide a standard of comparison against which surgeons can compare their own results, and they provide a benchmark for the evaluation of interventional techniques proposed to treat aneurysms.     

One surgeon's ten-year experience with abdominal aortic aneurysm surgery in smaller community hospitals

The results of one surgeon's 10-year experience with surgical treatment of abdominal aortic aneurysms are reviewed. There were 64 elective operations, eight operations on expanding aneurysms, and 19 procedures done for frank rupture. The mortality rate was 4.2% for the nonruptured aneurysm group compared with 36.8% for those patients with rupture. It may be suggested from this study that surgical treatment of abdominal aortic aneurysms can be done safely in low volume in smaller community hospitals and that such surgery need not be regionalized to larger institutions.     

Ruptured abdominal aortic aneurysm: factors influencing operative mortality

Of fifty-eight consecutive patients surgically treated for aneurysm of the abdominal aorta, twenty were emergency cases following the rupture. Associated diseases were found in 85 per cent of patients; hypertension being the most common. Fifty per cent of patients were in shock on admission. The duration between rupture and operation was three hrs to two weeks with the average of 115.5 hrs. In six patients, the diagnosis of abdominal aortic aneurysm was known for over six months. The operative mortality rate in case of ruptured abdominal aortic aneurysm was 45 per cent. The most important determinants of survival were the incidence of shock on admission, the incidence of associated disease, the known duration of the aneurysm, and the time interval from rupture to admission. The intraoperative factors most influencing survival were the type of rupture, intraoperative hypotension, and total blood loss. Comparison of the mortality rate in elective surgery of abdominal aortic aneurysms (5.3 per cent) with that in ruptured aneurysms (45.0 per cent) suggests the necessity for early elective operations whenever abdominal aortic aneurysms are diagnosed.     

Sutureless intraluminal graft for repair of abdominal aortic aneurysm

A series of seven patients undergoing elective repair of abdominal aortic aneurysms using sutureless intraluminal aortic prostheses for infrarenal tube grafts was reviewed. Follow-up was five to seven months. There was no morbidity related to the graft and one late mortality. In the uncomplicated cases, the average total operative time was two hours 14 minutes with no bank blood transfusions. The overall average operative time was two hours 41 minutes with an average operative transfusion of 0.28 units and total transfusions of 1.70 units of bank blood per case. Based on this experience and the observation that operative time and blood loss are major determinants of mortality with emergency abdominal aortic aneurysm repairs, we believe that use of sutureless intraluminal prostheses in suitable cases of leaking or ruptured abdominal aortic aneurysms has the potential to markedly improve survival.     

The risk of vascular surgery in a metropolitan community. With observations on surgeon experience and hospital size

From 1978 through 1981 complete perioperative information concerning a total of 10,189 peripheral vascular procedures performed in northeastern Ohio was recorded in the computer registry of The Cleveland Vascular Society. This report is an analysis of mortality and morbidity rates for all 5686 operations involving carotid endarterectomy (N = 2646), lower extremity revascularization (N = 1987), and abdominal aortic aneurysm resection (N = 1053). The operative mortality rate was 1.2% for carotid reconstruction, 2.8% for femoropopliteal or distal bypass, 3.5% for aortofemoral revascularization, and 11.9% for aortic aneurysm resection (elective operations 6.5%; emergency operations 32.9%). Postoperative strokes occurred after endarterectomy in 2.7% of patients having preoperative neurologic symptoms and in 2.0% of those with asymptomatic carotid stenosis. Lower extremity amputation was unavoidable in 1.5% of patients after aortofemoral reconstruction and in 6.0% after femoropopliteal or distal bypass. Statistical testing indicated that the operative mortality rate was not related to the respective size of the 27 hospitals involved in the survey. The relative annual experience of the 29 participating surgeons significantly influenced only the mortality rate of elective aneurysm resection and the amputation rate after femoropopliteal or distal revascularization. This study suggests that the results of major arterial reconstruction in metropolitan areas may be expected to be comparable to those of published series if the responsible surgeons are specifically trained and maintain an active interest in the field of vascular surgery.     

In-hospital mortality of ruptured abdominal aortic aneurysm

Background: New Zealand, like Australia, has a widely dispersed population in towns at long distances from the main centres. We set out to estimate the in‐hospital mortality rate for ruptured abdominal aortic aneurysms in New Zealand and identify factors associated with mortality. Methods: Data were gathered prospectively as part of the Vascular Society of New Zealand’s continuous audit programme of all member surgeons. Data collection was validated by random record audit. In‐hospital mortality of ruptured abdominal aortic aneurysms, defined as death during hospital admission irrespective of cause, was determined for the period 1993–2005. Along with other performance indicators, differences in outcomes were assessed to take into account the trend over the time period, hospital size and number of non‐operative admissions. Results: Of the 740 patients admitted with a mean age of 73.9 ± 8.5 years, 78% were men and 17.8% were declined an operation. The in‐hospital mortality was 48.3% and the operative mortality was 37.8%. With univariate analysis increasing patient age, American Society of Anesthesiology score, hospital size and female sex were predictors of in‐hospital mortality. Only age and American Society of Anesthesiology score were independent predictors of operative mortality. Women were less likely to have surgery. Conclusion: Over the past 13 years in‐hospital mortality of ruptured abdominal aortic aneurysms in New Zealand remained unchanged. In provincial hospitals the operative outcomes were satisfactory, but the reported number not offered surgery was higher.     

Aneurysm of the thoracic aorta. Review of 260 cases

In a 1980 review of the natural history and treatment of 176 thoracic aortic aneurysms, we noted the high incidence of rupture (47% overall) in 135 patients not treated surgically. Since that original study we have added another 84 patients to our series and have noted a complete change in management such that most patients are now treated surgically. We now have 260 patients in our series, 126 of whom were treated surgically. Sixty-seven were emergency operations and 59 were elective. Surgical mortality was 8% for elective resection and 33% for emergency operation. Over the past 5 years these figures have improved to 5% surgical mortality for elective resection and 16% surgical mortality for emergency resection. The 5 year survival rates for the entire series were 50% for patients treated with elective operation, 30% for combined emergency and elective operation groups, and 21% for nonsurgically treated patients. Abdominal aortic aneurysm was present in 74 patients (28%) and 23 of these patients had undergone a prior resection of an abdominal aortic aneurysm. This series documents the improved survival of patients with aneurysms of the thoracic aorta who are treated with prompt surgical intervention. It also further substantiates earlier findings of a high incidence of aneurysms of the abdominal aorta in this patient population.     

Abdominal aortic aneurysms in Western Australia: descriptive epidemiology and patterns of rupture

All abdominal aortic aneurysms presenting to hospitals and coroners in Western Australia over an 11-year period (January 1971 to December 1981) have been reviewed. A total of 1237 abdominal aortic aneurysms were found. After age and sex standardization it was apparent that the prevalence of diagnosis of abdominal aortic aneurysms had increased from 74.8 per 100 000 to 117.2 per 100 000 for men over 55 years of age (increase of 56.7 per cent) and from 17.5 per 100 000 to 33.9 per 100 000 for women over 55 years of age (increase of 93.7 per cent) during this period. One hundred and twenty-three patients were identified by coroner's autopsy after sudden death from ruptured abdominal aortic aneurysms in whom there had been no previous diagnosis of abdominal aortic aneurysm. Between 1971 to 1981, 478 patients underwent surgery; 225 had elective resection of their aneurysm with a 4.0 per cent fatality rate, and 253 had emergency operations with a 31.2 per cent fatality rate. Seasonal variations contributing to the date of emergency presentation or death from rupture of abdominal aortic aneurysms indicated a possible influence of colder weather upon rupture. It is hoped that the information provided in this paper will be of use to surgeons and physicians involved in health care planning for similar populations.     

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.     

Ruptured abdominal aortic aneurysm: Factors influencing operative mortality

Of fifty-eight consecutive patients surgically treated for aneurysm of the abdominal aorta, twenty were emergency cases following the rupture. Associated diseases were found in 85 per cent of patients; hypertension being the most common. Fifty per cent of patients were in shock on admission. The duration between rupture and operation was three hrs to two weeks with the average of 115.5 hrs. In six patients, the diagnosis of abdominal aortic aneurysm was known for over six months. The operative mortality rate in case of ruptured abdominal aortic aneurysm was 45 per cent. The most important determinants of survival were the incidence of shock on admission, the incidence of associated disease, the known duration of the aneurysm, and the time interval from rupture to admission. The intraoperative factors most influencing survival were the type of rupture, intraoperative hypotension, and total blood loss. Comparison of the mortality rate in elective surgery of abdominal aortic aneurysms (5.3 per cent) with that in ruptured aneurysms (45.0 per cent) suggests the necessity for early elective operations whenever abdominal aortic aneurysms are diagnosed. Presented at the Fifteenth Annual Meeting of the Japanese Association for Cardiovascular Surgery, Kanazawa, Japan, May 17–18, 1985.     

Technical aspects in the management of abdominal aortic aneurysms

During the past decade, resection of abdominal aortic aneurysms has become common. The technical aspects of the operation are now relatively standardized and simplified. With concomitant improvements in anesthesia and intensive care, the operative mortality for elective resection of these aneurysms has declined progressively; several centres report an operative mortality of less than 5%. The author considers the following principles important in managing patients with abdominal aortic aneurysms: (a) simplicity and limited dissection are critical features of the operative technique; (b) tubular grafts should be used whenever possible; (c) selected patients should be transferred to the intensive care unit preoperatively for "fine-tuning" of the cardiovascular system; (d) patients should be monitored intraoperatively and postoperatively; (e) the surgeon should be aware of special problems such as horseshoe kidney, venous anomalies, adherent duodenum and the presence of major arteries arising from the aneurysm; (f) ruptured aneurysms should be diagnosed promptly and the patient operated upon without delay. Using these principles, the author's group achieved an operative mortality of only 1.8% in 168 patients with abdominal aortic aneurysms resected electively. However, the operative mortality for their patients with ruptured aortic aneurysms was 50%, a rate that has not changed appreciably over the years.     

Survival improvement following aortic aneurysm resection.

Abdominal aortic aneurysm resections were performed on 298 patients between January, 1966 and December, 1973. The results were compared with 186 resections previously reported between 1955-1965. Hospital mortality rates for elective resections were 13% in 1955-1965, 8.4% in 1966-1973, and 4.2% in the 113 patients treated during the last 3 years. Urgent resections for intact aneurysms, previously associated with a 36% mortality, resulted in a 6% mortality rate in 1966-1973. The emergency resection mortality rate for ruptured aneurysm, originally 69%, was reduced to a present day over-all mortality of 55%, and 42% for the last 3 years. Calculated actuarial survival at 5 years was 65% for urgent (intact), 60% for elective and 40% for emergency (ruptured) groups. Atherosclerosis remains the major deterrent to long-term survival with myocardial infarction and stroke causing 43% of deaths occurring within 5 years. Improved survival appeared secondary to better operative technique, postoperative patient monitoring, increased surgical experience, and more elective resections of smaller, asymptomatic aneurysms than in 1955-1965. With present day low mortality rates, elective resection should be recommended in all patients without significant medical contraindications.     

Surgical Treatment of Inflammatory Abdominal Aortic Aneurysms: A Long-Term Follow-up of 19 Patients

The prevalence of inflammatory abdominal aortic aneurysms (IAAA) in autopsy material ranges between 2.5 and 10% of all aneurysms. Clinical findings, the distinction between inflammatory and degenerative aneurysms, and epidemiological data are uncertain, and only a few long-term follow-up studies of patients after surgical treatment of IAAAs exist. In this study, 19 patients underwent either emergency or elective surgery for IAAA during the 10-year period between 1983 and 1993 at Helsinki University Central Hospital. Demographics, symptoms, and operative and follow-up data were collected retrospectively with emphasis on the long-term outcome of IAAA. Causes of late death were available from hospital records and the central statistical office of Finland. For survival analysis we compared ruptured versus nonruptured and emergency versus elective cases of IAAAs. Mean follow-up for the 18 surviving patients (1 hospital death) was 7.4 years. One patient (5%) died of a long-term complication of the aneurysmal disease. There was no statistically significant difference in survival rates for emergency versus elective surgery cases or ruptured versus nonruptured aneurysms. The most common cause of late death was myocardial infarction. The hospital stay mortality (5%) and morbidity (31%), and the survival rate of 26% at 5 years for ruptured and 65% and 43% for nonruptured IAAAs at 5 years and 10 years, respectively, are comparable to normal AAA survival rates. These findings show that surgery is recommended, especially as ruptures also occur in this subgroup of aneurysms.     

Management of ruptured or symptomatic abdominal aortic aneurysms

During the past 15 years, the operative mortality for elective repair of abdominal aortic aneurysms has declined; this favorable trend has very likely resulted from simplified operative technique and improved perioperative management. Unfortunately, however, there has been no comparable decline in the mortality associated with repair of ruptured abdominal aortic aneurysms. The management of these patients remains a challenge to even the most skilled and experienced vascular surgeon.     

Elective aneurysm repair and the incidence of aortic rupture in an ageing population

During the period January 1984-July 1988, 191 abdominal aortic aneurysms were encountered at Gosford District Hospital, NSW, a hospital that services an ageing population. These aneurysms were either repaired or found as the cause of death at post-mortem. During the study, the rate of elective repair rose from 0.25/month during the first 2 years to 3.67/month in the latter 2.5 years. The mortality for repair of non-ruptured aneurysms was 0.9% compared with 55% for ruptured aneurysms. The 15-fold increase in elective repair resulted in the 58% reduction in the incidence of abdominal aortic rupture from 1.87/month to 0.79/month. The mortality rate from known aneurysms fell from 46% to 14% in the final 2 years. Elective aneurysm repair reduces the incidence of and death from abdominal aortic rupture in an ageing population.     

Influence of presentation on outcome in abdominal aortic aneurysm repair.

OBJECTIVES: In the absence of formal screening abdominal aortic aneurysms (AAA) are detected in an opportunistic manner. Many remain asymptomatic and undetected until they rupture. Incidentally discovered small AAAs are entered into a surveillance programme until they reach a suitable size for repair. The aim of this study was to examine trends in the management of AAA and whether the method of presentation had an effect on subsequent mortality. DESIGN: Observational study in UK district general hospital. MATERIALS/METHODS: This study reports a single surgeon case series identified using a prospectively maintained database. Data on mode of presentation, management and mortality were retrieved from case notes, PIMS hospital database and the Office of National Statistics. RESULTS: Two hundred and five patients were referred with AAAs between 1992 and 2004, 78% presenting in elective circumstances. The surveillance programme fed 33% of the operated cases. Two aneurysms ruptured whilst under surveillance. Overall elective operative mortality was 11.8% and has progressively decreased over time. Thirty-day operated mortality was significantly lower in patients having a period of surveillance than those having immediate elective repair (2.3 vs. 16.3%, p=0.018). A slight reduction in emergency AAA repairs was noted over the study period (r2=0.6) although registered aneurysm deaths continue to increase (r2=0.83). CONCLUSIONS: Elective mortality following AAA surgery decreased over the study period. Outcome was better in those patients who had surgery for aneurysms that had been under surveillance. Despite opportunistic screening the population adjusted mortality rate of aortic aneurysms showed a progressive increase. A reduction in deaths from aneurysms is unlikely without a formal screening programme.