Abdominal aortic aneurysm: ten years' hospital population study in the city of Glasgow

Incidence and Prevalence of Thoracic Aortic Aneurysms: A Systematic Review and Meta-analysis of Population-Based Studies

Thoracic aortic aneurysms (TAA) may grow asymptomatically until they rupture, with a mortality over 90%. The true incidence and prevalence of this condition is uncertain and epidemiologic data is scarce, understudied and dispersed. Therefore, we aimed to conduct a systematic review and meta-analysis of the incidence and prevalence of TAAs in population-based studies. We searched MEDLINE, EMBASE and CENTRAL from inception to October 2020 for all population-based studies reporting on incidence and/or prevalence of TAAs. Data were pooled using a random effects model. The main outcome was the overall available worldwide incidence and prevalence of TAAs. The secondary outcomes were to evaluate the incidence of ruptured TAAs, differences in the location of these aneurysms (either ascending, arch or descending aorta) and differences in prevalence/incidence across different study designs. Twenty-two studies were included in the review and meta-analysis. The pooled incidence and prevalence of TAAs was 5.3 per 100,000 individuals/year (95% confidence interval [CI]: 3.0; 8.3) and 0.16% (95% CI: 0.12; 0.20), respectively. The pooled incidence of ruptured aneurysms was 1.6 per 100,000 individuals/year (95% CI: 1.3; 2.1). We found a significant difference of the prevalence in autopsy-only studies, which was 0.76% (95% CI: 0.47; 1.13) and the prevalence of TAAs dropped down to 0.07% (95% CI: 0.05;0.11) when these studies were excluded from the overall analysis. The current epidemiologic information provided serve as a base for future public-health decisions. The lack of well-design population-base studies and the limitations encountered serve as calling for future research in this field.

How to better identify patients at high risk of postoperative complications?

PURPOSE OF REVIEW

Preoperative risk assessment and perioperative factors may help identify patients at increased risk of postoperative complications and allow postoperative management strategies that improve patient outcomes. This review summarizes historical and more recent scoring systems for predicting patients with increased morbidity and mortality in the postoperative period.

RECENT FINDINGS

Most prediction scores predict postoperative mortality with, at best, moderate accuracy. Scores that incorporate surgery-specific and intraoperative covariates may improve the accuracy of traditional scores. Traditional risk factors including increased ASA physical status score, emergent surgery, intraoperative blood loss and hemodynamic instability are consistently associated with increased mortality using most scoring systems.

SUMMARY

Preoperative clinical risk indices and risk calculators estimate surgical risk with moderate accuracy. Surgery-specific risk calculators are helpful in identifying patients at increased risk of 30-day mortality. Particular attention should be paid to intraoperative hemodynamic instability, blood loss, extent of surgical excision and volume of resection.

Changes in Referral Practice, Workload, and Operative Mortality after Establishment of an Endovascular Abdominal Aortic Aneurysm Program

Purpose:

To determine the change in referral practice following establishment of an endovascular abdominal aortic aneurysm (AAA) program.

Methods:

A prospective audit of all elective admissions for AAA was established in January 1994 at the initiation of an endovascular AAA program. A comparison was made between this cohort and the elective AAA repairs performed between 1981 and 1993.

Results:

Since January 1994, 213 AAA patients (177 men; median age 73 years, range 54 to 88) have been referred for potential endovascular aneurysm repair. To date, 142 patients have undergone elective surgery (41 endovascular and 101 conventional). Between 1981 and 1993, 304 patients (255 men; median age 69 years, range 45 to 86) had elective aneurysm repair. Comparison of the two time periods has revealed significant increases in the number of tertiary referrals (41.8% versus 9.5%, p < 0.01), annual operations (50 versus 23, p < 0.05), and overall mortality (12% versus 6.7%, p < 0.05), the latter attended by a significant increase in cardiorespiratory comorbidity.

Conclusions:

The higher elective AAA mortality rate since the establishment of an endovascular program reflects a change in referral practice and may be directly attributable to an increase in the number of high-risk patients. An endovascular AAA program has clinical and financial implications for the hospital concerned.

Implications of attendance patterns in Northern Ireland for abdominal aortic aneurysm screening

INTRODUCTION

Evidence supports the introduction of an abdominal aortic aneurysm (AAA) screening programme. The aims of this study were to estimate future disease patterns and to determine the effect of the proportion attending on the programme's cost-effectiveness.

PATIENTS AND METHODS

The results of the local AAA screening programme were reviewed. Ultrasonic infrarenal aortic diameter of 30 mm was considered aneurysmal. Projected population numbers from the Department of Health and current disease prevalence were used to estimate future number of potential patients. The Multi-centre Aneurysm Screening Study (MASS) Markov model was used to calculate an incremental cost-effectiveness ratio (ICER) and 95% uncertainty intervals (UI), using a 30-year time horizon and 3.5% per annum discount, to determine the effect of attendance.

RESULTS

Men were recruited from August 2004 to May 2010. 13316 were invited for a scan and 5931 (44.5%) attended. 321 AAA were diagnosed, giving a prevalence of 5.4%, while 27 large AAA (0.46%) were repaired. The annual incidence of AAA until 2021 will range from 441 to 526, with an incidence of 40-48 large AAA, with both showing a gradual increase with time. Using this attendance rate, the ICER was calculated at £2350 per life-year gained (95% UI: £1620-£4290), or £3020 per quality-adjusted life-year gained (95% UI: £2080-£5500).

CONCLUSIONS

The prevalence of disease in this local AAA screening was similar to other studies. The low attendance will result in many AAA being missed, but will not impact greatly on the long-term cost-effectiveness.

To what extent has endovascular aneurysm repair influenced abdominal aortic aneurysm management in the state of Illinois?

PURPOSE

This study was performed using population-based data to determine the changing trends in the techniques for abdominal aortic aneurysm (AAA) repair in the state of Illinois during the past 9 years and to examine the extent to which endovascular aneurysm repair (EVAR) has influenced overall AAA management.

METHODS

All records of patients who underwent AAA repair (1995 to 2003 inclusive) were retrieved from the Illinois Hospital Association COMPdata database. The outcome as determined by in-hospital mortality was analyzed according to intervention type (open vs EVAR) and indication (elective repair vs ruptured AAA). Data were stratified by age, gender, and hospital type (university vs community setting) and then analyzed using both univariate (chi 2 , t tests) and multivariate (stepwise logistic regression) techniques.

RESULTS

Between 1995 and 2003, 14,517 patients underwent AAA repair (85% for elective and 15% for ruptured AAA). The average age was 71.4 +/- 7.9 years, and 76% were men. For elective cases, open repair was performed in 86% and EVAR in 14%; and for ruptured cases, open repair in 97% and EVAR in 3%. Elective EVAR was associated with lower in-hospital mortality compared with open repair regardless of age. No differences were observed with age after either type of repair for a ruptured aneurysm. Men had a lower in-hospital mortality compared with women for open repair of both elective and ruptured aneurysms. For EVAR, the mortality of an elective repair was lower in men, but there was no difference after a ruptured AAA. In men, the difference in mortality between elective open repair and EVAR was significant; the type of institution did not influence outcome. Patients >80 years of age had a higher mortality after open repair for both elective and ruptured AAA and after EVAR of a ruptured AAA. The average length of stay was 9.9 days for open elective repair, 13.1 days after open repair of a ruptured AAA, and 3.6 days for EVAR. The independent predictors of higher in-hospital mortality were female gender, age >80 years, diagnosis (ruptured vs open), and procedure (open vs EVAR). The year of the procedure and type of hospital (university vs community) were not predictive of outcome.

CONCLUSIONS

EVAR has had a significant impact on AAA management in Illinois over a relatively short time period. In this population-based review, EVAR was associated with a significantly decreased in-hospital mortality and length of stay. Octogenarians had higher mortality after both types of repair, with the exception of elective EVAR.

AAA elective treatment indication tactics in EVAR era

The authors describe their indication tactics for AAA elective treatment. Based on one-month morbidity and mortality they evaluate the results obtained in the past six years and compare the methods of open surgery, endovascular repair and combined strategy in AAAs elective repair.

Abdominal aortic aneurysm: diagnosis, treatment, and implications for advanced practice nursing

The nurse practitioner needs to acknowledge that not all patients are insightful. The patient who is naive, stoical, or in denial may not return to his previous level of health. Behavioral or environmental changes may be a necessary part of recovery. The advanced practice nurse, through her research and subsequent knowledge, can identify and implement holistic changes necessary for the maintenance of health and the development of appropriate health-seeking behaviors that lower the morbidity and mortality for such conditions as abdominal aortic aneurysms. Nurse practitioners play a vital role in research, prevention and early detection of major threats to wellness (Lawler and Schmidt, 1992). Gender-sensitive research regarding factors affecting recovery are also necessary as females respond differently to such conditions as renal failure (Carlson and Eisenstat, 1995).

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.

Changes in referral practice, workload, and operative mortality after establishment of an endovascular abdominal aortic aneurysm program

PURPOSE

To determine the change in referral practice following establishment of an endovascular abdominal aortic aneurysm (AAA) program.

METHODS

A prospective audit of all elective admissions for AAA was established in January 1994 at the initiation of an endovascular AAA program. A comparison was made between this cohort and the elective AAA repairs performed between 1981 and 1993.

RESULTS

Since January 1994, 213 AAA patients (177 men; median age 73 years, range 54 to 88) have been referred for potential endovascular aneurysm repair. To date, 142 patients have undergone elective surgery (41 endovascular and 101 conventional). Between 1981 and 1993, 304 patients (255 men; median age 69 years, range 45 to 86) had elective aneurysm repair. Comparison of the two time periods has revealed significant increases in the number of tertiary referrals (41.8% versus 9.5%, p < 0.01), annual operations (50 versus 23, p < 0.05), and overall mortality (12% versus 6.7%, p < 0.05), the latter attended by a significant increase in cardiorespiratory comorbidity.

CONCLUSIONS

The higher elective AAA mortality rate since the establishment of an endovascular program reflects a change in referral practice and may be directly attributable to an increase in the number of high-risk patients. An endovascular AAA program has clinical and financial implications for the hospital concerned.

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.

The use of tonometry to predict mortality in patients undergoing abdominal aortic aneurysm repair

OBJECTIVE

To assess the reliability of intramucosal pH (pHi) of the sigmoid colon, IL-6 concentration and the APACHE II score in predicting outcome in patients undergoing elective abdominal aortic aneurysm repair.

DESIGN

Prospective study.

METHODS

In 42 patients, measurements were made of the sigmoid pHi with the silicone tonometer and plasma IL-6 by enzyme linked immuno-sorbent assay (ELISA). The daily postoperative APACHE II scores were also calculated. In 29 patients a preoperative left ventricular ejection fraction was determined by gated radionuclide angiography.

RESULTS

Four out of 42 patients who were studied died. The lowest perioperative pHi, the peak postoperative IL-6 concentration and APACHE II scores were significantly different in the survivors in comparison to the non-survivors. In the non-survivors, the fall in pHi preceded the time of patient's demise by at least 4 days. Significant correlations were observed between changes in pHi, IL-6 and APACHE II. Using receiver operating characteristic curves, pHi was shown to be the most predictive of mortality compared to the other variables. The simplicity, speed and practicality of using the tonometer adds to its superiority over the latter measurements. No relationship was found between ventricular ejection fraction, pHi and outcome.

CONCLUSION

Although the number of patients is small, these results support pHi as a valuable predictor of outcome and also suggest a role for the gut in initiating the IL-6 and physiological responses.

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.

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

OBJECTIVE

Assessment of mortality and long-term relative survival following repair of asymptomatic abdominal aortic aneurysms.

DESIGN

Retrospective review.

SETTING

University Hospital.

MATERIALS

Three hundred and twenty seven patients with a median age of 68 years and male to female proportion of 10:1.

CHIEF OUTCOME MEASURES

Operative mortality and long-term mortality obtained from Norwegian Registrar's Office. Demographically matched expected survival calculated from death rate tables published by the Norwegian Central Bureau of Statistics.

MAIN RESULTS

The overall operative mortality was 5.2%. Ten-year survival rate for all the patients was 38% compared to the expected of 52%. The standard mortality rate was 1.30, indicating a 30% higher mortality compared to a demographically matched population. Older patients and patients with known cardiac disease had significantly increased operative mortality. These patients also had the lowest long-term survival. Patients with cardiac disease suffered a postoperative mortality more than two times expected.

CONCLUSIONS

Further studies are needed to define subgroups unsuitable for elective surgery.

Trends in abdominal aortic aneurysms: a 13 year review

AIM

To assess changing trends of abdominal aortic aneurysms 1979-1991.

DESIGN

Retrospective study from the Leicestershire Health Authority.

RESULTS

727 patients with abdominal aortic aneurysm were treated. Of these 56.4% were admitted for elective repair and 43.6% presented with rupture. There was a significant increase in the number of ruptured aortic aneurysms over this period despite an increase in the number of elective repairs. The overall 30-day mortality of elective repair (including patients with symptomatic but non-ruptured aneurysms) was 8.8%. The overall 30-day mortality of ruptured aneurysms (including patients who were deemed medically too unfit for surgery) was 57.7%. There has been no significant change in elective and ruptured mortality over the study period. There was a significant increase in the median age of patients (69.5 yrs in 1979 to 74 yrs in 1991).

CONCLUSION

The increasing incidence of abdominal aortic aneurysms may reflect better diagnostic methods, greater clinical awareness of the condition and increase in the proportion of elderly people in the population.