Infrarenal abdominal aortic aneurysms less than five centimetres in diameter: The surgeon's dilemma

doi:10.1016/S0950-821X(05)80838-2

European Journal of Vascular Surgery

Volume 6, Issue 6, November 1992, Pages 616-622

https://doi.org/10.1016/S0950-821X(05)80838-2 Get rights and content

A number of recent studies have brought new data and a better understanding of the risk versus benefit of abdominal aortic aneurysm repair. The present evidence indicates that the risk of rupture for non tender aneurysms less than 5cm is so low that patients can generally be followed by 6 monthly ultrasound and not undergo immediate operation. Surgery should be the method of choice for most patients where the aneurysm is greater than 5cm.

References (55)

GlimakerH et al.
Natural history of patients with abdominal aortic aneurysm
Eur J Vasc Surg
(1991)
CollinJ et al.
How fast do very small abdominal aortic aneurysms grow?
Eur J Vase Surg
(1989)
AuerbachO et al.
Atherosclerosis and aneurysm of the aorta in relation to smoking habits and age
Chest
(1980)
SterpettiAV et al.
Abdominal aortic aneurysm in elderly patients
BrownPM et al.
The selective management of smal abdominal aortic aneurysms: the Kingston study
J Vasc Surg
(1992)
RogerVL et al.
Influence of coronary artery disease on morbidity and mortality after abdominal aortic aneurysmectomy: a population based study 1971–1987
JACC
(1989)
SalmasiAM et al.
Intermittent claudication as a manifestation of silent myocardial ischaemia: a pilot study
J Vasc Surg
(1991)
McPhailNV et al.
A comparison of dipyridamole thallium imaging and exercise testing in the prediction of postoperative cardiac complications in patients requiring arterial reconstruction
J Vasc Surg
(1989)
McEnroeCS et al.
Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery
J Vasc Surg
(1990)
JohnstonKW
Multicenter prospective study on nonruptured abdominal aortic aneurysm. Part II. Variables predicting morbidity and mortality
J Vasc Surg
(1989)

HertzerNR et al.

The risk of vascular surgery in a metropolitan community with observation on surgeon experience and hospital size

J Vasc Surg

(1984)

OPCS (Office of Population Censuses and Surveys)

Mortality statistics

(1989)

OPCS (Office of Population Censuses and Surveys)

Mortality statistics: cause

(1984)

SilverbergE et al.

Cancer Statistics 1983

(1983)

NevittMP et al.

Prognosis of abdominal aortic aneurysms. A population based study

N Engl J Med

(1989)

JohnssonG et al.

Survival in patients with abdominal aortic aneurysms

AllardiceJT et al.

High prevalence of abdominal aortic aneurysm in men with peripheral vascular disease: screening by ultrasonography

Br J Surg

(1988)

CronenwettJL et al.

Actuarial analysis of variables associated with rupture of small abdominal aortic aneurysms

Surgery

(1985)

ScottRAP et al.

Routine ultrasound screening in management of abdominal aortic aneurysm

Br Med J

(1988)

EllisM et al.

Limitations of ultrasonograhy in surveillance of small abdominal aortic aneurysms

Br J Surg

(1991)

OurielK et al.

An evaluation of new methods of expressing aortic aneurysm size

BernsteinEF et al.

Abdominal aortic aneurysm in high risk patients

DarlingCR et al.

Autopsy study of unoperated abdominal aortic aneurysms. The case for early resection

Circulation

(1977)

TurkK

Post-mortem incidence of abdominal aortic aneurysms

SommervilleRL et al.

Bland and infected arteriosclerotic abdominal aortic aneurysms: a clinico-pathologic study

Medicine

(1959)

CarlssonJ et al.

Aortic aneurysms

Acta Chir Scand

(1964)

FowkesFGR et al.

Increasing incidence of aortic aneurysms in England and Wales

Br Med J

(1989)

Cited by (29)

Characteristics and 1-year outcomes of patients with rupture of small abdominal aortic aneurysms
2023, Journal of Vascular Surgery
Ruptured abdominal aortic aneurysms (rAAA) are associated typically with a large sac diameter; however, some patients experience rupture before reaching operative thresholds for elective repair. We aim to investigate the characteristics and outcomes of patients who experience small rAAA.
The Vascular Quality Initiative database for open AAA repair and endovascular aneurysm repair from 2003 to 2020 were reviewed for all rAAA cases. Based on the 2018 Society for Vascular Surgery guidelines on operative size thresholds for elective repair, patients with infrarenal aneurysms of less than 5.0 cm in women or less than 5.5 cm in men were categorized as a small rAAA. Patients who met operative thresholds or had a concomitant iliac diameter 3.5 cm or greater were categorized as a large rAAA. Patient characteristics and perioperative as well as long-term outcomes were compared via univariate regression. Inverse probability of treatment weighting using propensity scores was used to examine the relationship between rAAA size and adverse outcomes.
There were 3962 cases that met inclusion criteria, with 12.2% small rAAA. The mean aneurysm diameter was 42.3 mm and 78.5 mm in the small and large rAAA groups, respectively. Patients in the small rAAA group were significantly more likely to be younger, African American, have a lower body mass index, and had significantly higher rates of hypertension. Small rAAA were more likely to be repaired via endovascular aneurysm repair (P = .001). Hypotension was significantly less likely in patients with small rAAA (P<.001). Rates of perioperative myocardial infarction (P < .001), total morbidity (P < .004) and mortality (P < .001) were significantly higher for large rAAA cases. After propensity matching, there was no significant difference in mortality between the two groups, but smaller rAAA was associated with lower rates of myocardial infarction (odds ratio, 0.50; 95% confidence interval, 0.31-0.82). On long-term follow-up, no difference in mortality was noted between the two groups.
Patients presenting with small rAAA represent 12.2% of all rAAA and are more likely to be African American. Small rAAA is associated with similar risk of perioperative and long-term mortality compared with rupture at larger size after risk adjustment.
Characteristics and outcomes of small abdominal aortic aneurysm rupture in the American College of Surgeons National Surgical Quality Improvement Program database
2021, Journal of Vascular Surgery
Citation Excerpt :
However, the case series from Harborview Medical Center found a significantly greater rate of COPD in patients with small rAAAs compared with patients with large rAAAs (64% vs 25%; P = .02), and another study suggested that patients with COPD will have AAAs that rupture at a larger size.7,9 The mortality rates related to rAAA repair have varied widely.27,28 On univariate analysis, the data from the present study suggest that the mortality rates for small rAAAs will be significantly lower than that with large rAAAs—17% vs 24%.
The current guidelines recommend elective abdominal aortic aneurysm (AAA) repair at 5.5 cm for men and 5.0 cm for women. However, rupture can occur in patients with an aneurysm smaller than these size thresholds. In the present study, we investigated the proportion of AAAs that rupture at sizes less than elective operative thresholds and compared the outcomes of repair with those of aneurysms that had ruptured at a larger size. Our hypothesis was that the rupture of small AAAs carries mortality similar to that of rupture at larger sizes.
The American College of Surgeons National Surgical Quality Improvement Program targeted vascular files for open AAA repair and endovascular aneurysm repair (EVAR) were reviewed for all cases of ruptured AAAs (rAAAs) from 2011 to 2018. The patients were divided into two groups: those with small AAAs that had ruptured at a size less than the current size guidelines for elective repair and those with large AAAs that had ruptured at a size that had met the criteria for elective repair. Univariate analyses were conducted to compare the comorbidities and perioperative outcomes of infrarenal rAAA repair between the groups. Multivariable logistic regression was performed to examine the differences in mortality between small and large rAAAs after controlling for confounding variables.
Of the 1612 rAAA repairs, 167 (10.4%) were small rAAAs. The proportion of small rAAAs did not significantly change during the study period (P = .15). The large rAAA group was more likely to have juxtarenal or suprarenal aneurysms compared with the small rAAA group (27% vs 16%; P = .001). A comparison of infrarenal rAAAs only demonstrated that the mean small rAAA (n = 141) diameter was 4.1 cm in the women and 4.5 cm in the men compared with the large rAAAs (n = 1051), with a mean diameter of 7.1 cm in women and 8.3 cm in men (P < .01 for the women; P < .01 for the men). The patients in the small rAAA group had had a significantly lower body mass index but were more likely to be African American and to have hypertension. The small rAAA group was more likely to present without hypotension and to have undergone EVAR. The repair of small rAAAs was associated with lower bleeding and mortality and a shorter mean operative time but with more readmissions. Multivariable regression analysis demonstrated that size was not associated with outcome after adjusting for other variables.
Of all AAA repairs classified as treating rupture, 10% were for patients with small AAAs. Patients with small rAAA were less likely to present with hypotension and were more likely to have undergone EVAR. Further research into sac morphology and more sensitive imaging modalities might help identify small rAAAs at high risk of rupture that would benefit from elective repair.
A novel combined fluid dynamic and strain analysis approach identified abdominal aortic aneurysm rupture
2020, Journal of Vascular Surgery Cases and Innovative Techniques
Clinical decision-making for surgical repair of abdominal aortic aneurysms based on maximum aortic diameter presents limitations as rupture can occur below threshold for some aneurysms, whereas others are stable at large sizes. The proposed approach combines hemodynamics and geometric indices with in vivo deformation analysis to assess local weakening of the aortic wall for a case of impending rupture that was confirmed during open surgical repair. A new combined index, the Regional Rupture Potential, is introduced to help the assessment of individual aneurysms and their rupture risk, providing a rationale for clinical decisions.
Incidence of small abdominal aortic aneurysms rupture, impact of comorbidities and our experience with rupture risk prediction based on wall stress assessment
2015, Cor et Vasa
Citation Excerpt :
According to current guidelines [2] the threshold for elective repair of an asymptomatic AAA is its maximal diameter bigger than 5.5 cm (measured in CT findings). Regardless of the guidelines, there is a large number of research showing that a considerable portion of ruptured AAA (10–24%) [3–5] is less than 5.5 cm in diameter (small ruptured AAA). This means that even dispensarized patients with a small AAA are in danger of a life-threatening rupture, even though they do not meet the criteria for AAA repair (Fig. 2).
Abdominal aortic aneurysm rupture (AAA) threatens a patient's life, requiring an urgent open repair or endovascular surgery. If an asymptomatic AAA is found before a rupture the next steps are directed by its diameter – if it is less than 55 mm the patient is dispensarized, and if it is more a repair is indicated. According to literary sources 10–24% of ruptured AAA are less than 55 mm in diameter, thus a significant portion of dispensarized patients are threatened by a rupture. The objective of our study was to determine a portion of small ruptured AAA repaired in our center in the last four years and try to identify potential risk factor. The secondary goal was to show our experience with a modern method of rupture prediction, using CT scans to compute the wall stress of AAA and thus predict its rupture risk.
A retrospective study of documentation of patients with ruptured AAA in last four years. CT findings were used to measure maximal diameter of ruptured AAA and portion of small AAA was determined. Some other important information from patient's medical history were also compared in both groups and statistically evaluated.
41 patients underwent an open repair of ruptured AAA. Out of this number 7 ruptured AAA were small, which is equivalent to 17.1%.
This finding shows us the shortages of the present indication criteria based on an AAA diameter. In accordance to these criteria patients with small AAA are dispensarized and thus a significant part of them are in risk of rupture.
Boundary conditions for flow simulations of abdominal aortic aneurysms
2014, International Journal of Heat and Fluid Flow
Citation Excerpt :
According to the traditional view, when the aneurysm sac reaches a certain size, there is an increasing risk of rupture. A long term goal of aneurysm research is to facilitate the estimation of the risk of rupture for medical doctors more objectively, based on statistical data and simulations, rather than on maximum transverse diameter (Gerouslakos and Nicolaides, 1992; Long et al., 2012). Some authors approach the problem from the wall mechanics point of view because rupture occurs when the stress in the wall reaches the failure strength (Raghavan et al., 2000).
Boundary conditions for abdominal aortic aneurysm simulations are problematic both on the fluid and the solid side. In this paper improvements are suggested on existing methodology in both respects.
First, a derivation of a hyperelastic wall model is given, taking into account the wall stresses at the diastolic instant. It is demonstrated that this model can be approximated with a simplified linear wall model in the physiologically interesting range.
Then a new method for inlet and outlet boundary condition generation is introduced on the fluid side, based on a one-dimensional transient simulator. Finally, the effect of spine support on the intra-aneurysmal flow is studied.
Good agreement was found between rigid wall flow simulations on the “systolic” geometry and the fluid–structure interaction simulations. Other authors found much larger differences because earlier the “diastolic” geometry had been used for comparisons and the stresses in the diastolic state were neglected. It was concluded that the spine support does not have a great impact on the flow field. Significant differences were found between the flow behaviour of artificially generated and real aneurysm geometries.
Biomechanics of abdominal aortic aneurysm
2007, Journal of Biomechanics
Abdominal aortic aneurysm (AAA) is a condition whereby the terminal aorta permanently dilates to dangerous proportions, risking rupture. The biomechanics of AAA has been studied with great interest since aneurysm rupture is a mechanical failure of the degenerated aortic wall and is a significant cause of death in developed countries. In this review article, the importance of considering the biomechanics of AAA is discussed, and then the history and the state-of-the-art of this field is reviewed—including investigations into the biomechanical behavior of AAA tissues, modeling AAA wall stress and factors which influence it, and the potential clinical utility of these estimates in predicting AAA rupture.

View all citing articles on Scopus

View full text

Original articleInfrarenal abdominal aortic aneurysms less than five centimetres in diameter: The surgeon's dilemma

Eur J Vasc Surg

Eur J Vase Surg

Chest

J Vasc Surg

JACC

J Vasc Surg

J Vasc Surg

J Vasc Surg

J Vasc Surg

J Vasc Surg

Mortality statistics

Mortality statistics: cause

Cancer Statistics 1983

Prognosis of abdominal aortic aneurysms. A population based study

N Engl J Med

Survival in patients with abdominal aortic aneurysms

High prevalence of abdominal aortic aneurysm in men with peripheral vascular disease: screening by ultrasonography

Br J Surg

Actuarial analysis of variables associated with rupture of small abdominal aortic aneurysms

Surgery

Routine ultrasound screening in management of abdominal aortic aneurysm

Br Med J

Limitations of ultrasonograhy in surveillance of small abdominal aortic aneurysms

Br J Surg

An evaluation of new methods of expressing aortic aneurysm size

Abdominal aortic aneurysm in high risk patients

Autopsy study of unoperated abdominal aortic aneurysms. The case for early resection

Circulation

Post-mortem incidence of abdominal aortic aneurysms

Bland and infected arteriosclerotic abdominal aortic aneurysms: a clinico-pathologic study

Medicine

Aortic aneurysms

Acta Chir Scand

Increasing incidence of aortic aneurysms in England and Wales

Br Med J

Original article
Infrarenal abdominal aortic aneurysms less than five centimetres in diameter: The surgeon's dilemma