Prevalence of abdominal aortic aneurysm in patients with occlusive peripheral vascular disease

Screening for Prevalence of Abdominal Aortic Aneurysm During Transthoracic Echocardiography in Patient With Significant Coronary Artery Disease

BACKGROUND

Prevalence of abdominal aortic aneurysm (AAA) has ethnic differences, and coronary artery disease (CAD) shares several risk factors with AAA. Sparse Indian data are available on this. We evaluated the prevalence of AAA during transthoracic echocardiography (TTE) and risk factors of AAA in patients with CAD.

METHODS

This was a prospective observational study carried out in the cardiology department at a tertiary care center from January 1, 2017 to November 30, 2017. All patients with CAD/acute coronary syndrome (ACS) were included in the study, and patients with AAA due to other etiology were excluded. Screening for an AAA was performed directly using an echocardiographic 3.5-MHz cardiac probe.

RESULTS

A total of 526 patients were screened; and AAA was present in 25 (4.8%) of CAD patients. Smoking, hypertension and hyperlipidemia were predominant risk factors for AAA in our study, but were not statistically significant because same risk factors were also prevalent in the comparison group. Diabetes, peripheral vascular disease and family history were statistically significant risk factors for AAA in our study. The mean size of AAA was 34 mm.

CONCLUSIONS

Presence of AAA is significantly higher among CAD patients. CAD shares several risk factors with AAA. Therefore, opportunistic examination of the abdominal aorta during routine TTE could be an effective way of screening. Diabetes mellitus, peripheral artery disease and family history were the significant associated risk factors of AAA in CAD patients.

Symptomatic and asymptomatic peripheral artery disease and the risk of abdominal aortic aneurysm: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

Symptomatic peripheral artery disease (PAD) is a risk factor for abdominal aortic aneurysm (AAA). However, data on the association of asymptomatic PAD with AAA are limited. We explored the association of symptomatic and asymptomatic PAD with AAA.

METHODS

We primarily assessed a prospective association of symptomatic (based on clinical history) and asymptomatic (ankle-brachial index ≤0.9) PAD at baseline (1987-89 [ages 45-64 years]) with incident AAA in a biracial community-based cohort, the Atherosclerosis Risk in Communities Study. We secondarily investigated a cross-sectional association of PAD with ultrasound-based AAA (diameter≥3.0 cm) (2011-13 [ages 67-91 years]).

RESULTS

Of 14,148 participants (55.1% female, 25.5% black, 0.9% with symptomatic PAD) in our prospective analysis (median follow-up 22.5 years), 530 (3.7%) developed incident AAA. Symptomatic PAD had a higher hazard ratio (HR) of incident AAA [4.91 (95%CI 2.88-8.37)], as did asymptomatic PAD with ABI≤0.9 [2.33 (1.55-3.51)], compared to the reference ABI>1.1-1.2 in demographically-adjusted models. Crude 15-year cumulative incidence of AAA in these three groups were 12.3%, 3.9%, and 1.5%, respectively. The associations remained significant after accounting for other potential confounders [corresponding HR 2.96 (95%CI 1.73-5.07) and 1.52 (95%CI 1.00-2.30), respectively]. The cross-sectional analysis demonstrated similar patterns with ultrasound-based AAA [odds ratio 2.46 (95%CI 1.26-4.81) for symptomatic PAD and 3.98 (1.96-8.08) for asymptomatic PAD in a demographically-adjusted model].

CONCLUSIONS

Our prospective and cross-sectional data show elevated risk of AAA in both symptomatic and asymptomatic PAD. Our data support the current recommendation of AAA screening in symptomatic PAD patients and suggest the potential extension to asymptomatic PAD patients as well.

Aortic Plaque Distribution, and Association between Aortic Plaque and Atherosclerotic Risk Factors: An Aortic Angioscopy Study

Aim: Knowledge of subclinical plaque morphology and plaque distribution in the aorta in vivo remains unclear. This study aimed to increase the body of knowledge in this area.

Methods: We enrolled 37 consecutive patients with stable angina pectoris patients who underwent non-obstructive angioscopy for both the coronary artery and aorta immediately after percutaneous coronary intervention. We evaluated the presence of aortic plaques and the distribution of plaque instability. Patients were allocated into two groups according to the number of vulnerable plaques in whole aorta (a low [0–11] and high [≥ 12] group). We evaluated the relationships between the two groups in terms of cardiovascular risk factors.

Results: Aortic plaques were identified using non-obstructive angioscopy in all patients, and the greatest number of plaques was found at the infrarenal abdominal aorta (IAA) (the aortic arch, the descending thoracic aorta, the suprarenal abdominal aorta, the IAA, and common iliac artery; 65%, 76%, 65%, 95%, and 49%, respectively; p < 0.001). The maximum yellow grade, and the number of intense yellow plaques, ruptured plaques, and thrombi were highest at the IAA (p < 0.001). The prevalence of diabetes mellitus and peripheral arterial disease was higher in the high vulnerable plaque group (83.3% vs. 40.0%, p = 0.010, 50.0% vs. 8.0%, p = 0.005, respectively).

Conclusions: Aortic atherosclerosis was the most severe at the IAA, and aortic plaque vulnerability and distribution were associated with the prevalence of diabetes mellitus and peripheral artery disease in patients with stable angina pectoris. Non-obstructive angioscopy may identify patients at high risk of future aortic events.

Abdominal aortic aneurysms and diabetes mellitus

There is accumulating evidence that risk profiles differ between coronary artery disease and abdominal aortic aneurysms (AAAs). However, diabetes mellitus (DM) appears to be negatively associated with AAA formation. The underlying mechanisms for this negative relationship are far from defined, but may include: increased arterial wall matrix formation via advanced glycation end products; suppression of plasmin and reduction of levels and activity of matrix metalloproteinases (MMP)-2 and 9; diminished aortic wall macrophage infiltration, elastolysis and neovascularization. In addition, the effect of pharmacological agents used for the treatment of patients with DM on AAA formation has been studied with rather controversial results. Statins, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, fenofibrate, antibiotics and some hypoglycemic agents are beginning to be appreciated for a potential modest protection from AAAs, but further studies are needed.

Risk Stratification of Patients with Peripheral Arterial Disease and Abdominal Aortic Aneurysm Using Aortic Augmentation Index

BACKGROUND

Central augmentation index (cAIx) is an indicator for vascular stiffness. Obstructive and aneurysmatic vascular disease can affect pulse wave propagation and reflection, causing changes in central aortic pressures.

AIM

To assess and compare cAIx in patients with peripheral arterial disease (PAD) and / or abdominal aortic aneurysm (AAA).

METHODS

cAIx was assessed by radial applanation tonometry (Sphygmocor) in a total of 184 patients at a tertiary referral centre. Patients were grouped as having PAD only, AAA only, or both AAA and PAD. Differences in cAIx measurements between the three patient groups were tested by non-parametric tests and stepwise multivariate linear regression analysis to investigate associations with obstructive or aneurysmatic patterns of vascular disease.

RESULTS

In the study sample of 184 patients, 130 had PAD only, 20 had AAA only, and 34 patients had both AAA and PAD. Mean cAIx (%) was 30.5 ± 8.2 across all patients. It was significantly higher in females (35.2 ± 6.1, n = 55) than males (28.4 ± 8.2, n = 129), and significantly higher in patients over 80 years of age (34.4 ± 6.9, n = 22) than in those under 80 years (30.0 ± 8.2, n = 162). Intergroup comparison revealed a significant difference in cAIx between the three patient groups (AAA: 27.3 ± 9.5; PAD: 31.4 ± 7.8; AAA & PAD: 28.8 ± 8.5). cAIx was significantly lower in patients with AAA, higher in patients with both AAA and PAD, and highest in patients with PAD only (beta = 0.21, p = 0.006).

CONCLUSION

Non-invasive assessment of arterial stiffness in high-risk patients indicates that cAIx differs according to the pattern of vascular disease. Measurements revealed significantly higher cAIx values for patients with obstructive peripheral arterial disease than for patients with aneurysmatic disease.

Abdominal Aortic Diameter and the Risk for Asymptomatic Peripheral Arterial Disease in Patients with Type 2 Diabetes

Peripheral arterial disease (PAD) is common among older people because it often results from atherosclerosis, which becomes more common with age. The disease is particularly common among people who have diabetes. Little information is available on the relation between abdominal aortic diameter and PAD in elderly patients with diabetes. This article studies the relationships between abdominal aortic diameter, PAD, and the cardiovascular risk factors in asymptomatic elderly patients suffering from type 2 diabetes mellitus. A case-control study was conducted on 90 participants aged 60 years and older divided into 60 cases (30 males and 30 females) and 30 age-matched healthy controls (15 males and 15 females). The relationships between the size of the abdominal aorta and ankle-brachial index (ABI), plasma cholesterol, triglycerides (TG), and high-sensitivity C-reactive protein were examined. Approximately, 15% of patients with diabetes had asymptomatic PAD. The patients with diabetes with PAD were of older age (70.4 ± 3.6 vs. 63.4 ± 3.9 years; p = 0.000), had larger abdominal aortic diameter (22.4 ± 3.08 vs. 18.7 ± 2 mm; p = 0.000), and higher CRP levels (8.3 ± 1.1 vs. 5.8 ± 2.2 mg/L; p = 0.002), while other variables revealed no significant difference. Abdominal aortic diameter correlated well with ABI measured by Doppler method in diabetic patients (r =  - 0.471, p = 0.000). Older age and larger abdominal aorta are independent risk factors for asymptomatic PAD in the elderly with type 2 diabetes mellitus.

Abdominal aortic aneurysm in patients affected by intermittent claudication: prevalence and clinical predictors

Background

Abdominal aortic aneurysm (AAA) is a frequent cause of death among elderly. Patients affected by lower extremity peripheral arterial disease (LE-PAD) seem to be particularly at high risk for AAA. We aimed this study at assessing the prevalence and the clinical predictors of the presence of AAA in a homogeneous cohort of LE-PAD patients affected by intermittent claudication.

Methods

We performed an abdominal ultrasound in 213 consecutive patients with documented LE-PAD (ankle/brachial index ≤0.90) attending our outpatient clinic for intermittent claudication. For each patient we registered cardiovascular risk factors and comorbidities, and measured neutrophil count.

Results

The ultrasound was inconclusive in 3 patients (1.4%), thus 210 patients (169 males, 41 females, mean age 65.9 ± 9.8 yr) entered the study. Overall, AAA was present in 19 patients (9.0%), with a not significant higher prevalence in men than in women (10.1% vs 4.9%, p = 0.300). Patients with AAA were older (71.2 ± 7.0 vs 65.4 ± 9.9 years, p = 0.015), were more likely to have hypertension (94.7% vs 71.2%, p = 0.027), and greater neutrophil count (5.5 [4.5 – 6.2] vs 4.1 [3.2 – 5.5] x10³/μL, p = 0.010). Importantly, the c-statistic for neutrophil count (0.73, 95% CI 0.60 – 0.86, p =0.010) was higher than that for age (0.67, CI 0.56–0.78, p = 0.017). The prevalence of AAA in claudicant patients with a neutrophil count ≥ 5.1 x10³/μL (cut-off identified at ROC analysis) was as high as 29.0%.

Conclusions

Prevalence of AAA in claudicant patients is much higher than that reported in the general population. Ultrasound screening should be considered in these patients, especially in those with an elevated neutrophil count.

Abdominal aortic aneurysm: Treatment options, image visualizations and follow-up procedures

Abdominal aortic aneurysm is a common vascular disease that affects elderly population. Open surgical repair is regarded as the gold standard technique for treatment of abdominal aortic aneurysm, however, endovascular aneurysm repair has rapidly expanded since its first introduction in 1990s. As a less invasive technique, endovascular aneurysm repair has been confirmed to be an effective alternative to open surgical repair, especially in patients with co-morbid conditions. Computed tomography (CT) angiography is currently the preferred imaging modality for both preoperative planning and post-operative follow-up. 2D CT images are complemented by a number of 3D reconstructions which enhance the diagnostic applications of CT angiography in both planning and follow-up of endovascular repair. CT has the disadvantage of high cummulative radiation dose, of particular concern in younger patients, since patients require regular imaging follow-ups after endovascular repair, thus, exposing patients to repeated radiation exposure for life. There is a trend to change from CT to ultrasound surveillance of endovascular aneurysm repair. Medical image visualizations demonstrate excellent morphological assessment of aneurysm and stent-grafts, but fail to provide hemodynamic changes caused by the complex stent-graft device that is implanted into the aorta. This article reviews the treatment options of abdominal aortic aneurysm, various image visualization tools, and follow-up procedures with use of different modalities including both imaging and computational fluid dynamics methods. Future directions to improve treatment outcomes in the follow-up of endovascular aneurysm repair are outlined.

Prevalence of coronary heart disease in patients with aortic aneurysm and/or peripheral artery disease

Although the presence of coronary heart disease (CHD) was the major determinant of perioperative mortality and long-term prognosis in patients with aortic aneurysm (AA) and peripheral artery disease (PAD), the prevalence and severity of CHD in patients with individual vascular diseases was unknown. Adenosine triphosphate-loading myocardial single-photon emission computed tomography therefore was performed in 788 patients with vascular diseases of the aorta and peripheral arteries, with AA in 500, PAD localized in the lower-limb arteries in 183, and combined AA and PAD in 105. Patients with known CHD, such as those with previous myocardial infarction or revascularization procedures, were excluded. Myocardial single-photon emission computed tomography was analyzed using a 20-segment model, and summed stress scores and summed difference scores were calculated. Stress-induced myocardial ischemia was defined as a summed difference score >or=2. The presence of myocardial ischemia was highest in patients with combined PAD and AA (73%), followed by PAD (55%; p = 0.005), and the lowest in patients with AA (37%; p <0.0001). Summed stress score was also the highest in patients with combined PAD and AA (11.6 +/- 9.9), followed by PAD (7.8 +/- 8.8; p <0.0001), and the lowest in patients with AA (4.0 +/- 6.2; p <0.0001 for both). Similarly, summed difference score was the highest in patients with combined PAD and AA (6.4 +/- 6.1), followed by PAD (4.4 +/- 5.7; p = 0.001) and AA (2.3 +/- 4.0; p <0.0001 for both). In conclusion, the prevalence of CHD in patients with PAD was >50%, and although myocardial ischemia was observed in only (1/3) of patients with AA, its prevalence not only doubled, but also indicated extensive myocardial ischemia when combined with PAD. Thus, cardiac evaluation was particularly important in patients with combined AA and PAD.

High-risk and low-risk screening for abdominal aortic aneurysm both reduce aneurysm-related mortality. A stratified analysis from a single-centre randomised screening trial

BACKGROUND

Cardiovascular diseases and chronic obstructive pulmonary disease (COPD) are both associated with abdominal aortic aneurysms (AAA). The aim of this study was therefore to analyse whether screening for AAA could be restricted to men with such diseases (high risk group).

METHODS

Before the date of randomisation of a population screening trial of 12,639 64-73-year-old males, all discharge diagnoses from the National Patient Registry concerning AAA-related diseases were merged with the screening results on attendance, AAA prevalence, and AAA-related mortality and overall mortality. Differences in proportions were compared by Chi square tests and differences in mortality by Cox regression analyses.

RESULTS

The attendance rate was 78.8% and 6.7% had an AAA in the high risk group compared to 75.8% attendance (P<0.001) and 2.9% (P<0.001) in the remaining population. Cumulatively, screening of only high risk men with would have required 72.9% (95% C.I.: 72.3-74.5%) fewer screening invitations, would have discovered 46.1% (95% C.I.: 38.9-53.4%) of the AAA cases diagnosed and prevented 46.7% (95% C.I.: 28.3-65.7%) of the AAA-related deaths. However, screening decreased AAA-related mortality both among men with and without known COPD or cardiovascular diseases: mortality ratio: 0.22 (95% C.I.: 0.08-0.65), P=0.006, and 0.24 (95% C.I: 0.09-0.63, P=0.004, respectively.

CONCLUSION

High-risk population screening would prevent less than half of AAA-related deaths. Therefore, restricting screening to such high-risk groups does not seem justified, but cost effectiveness analyses are needed to reach a firm conclusion.

Optimal scanning protocol of multislice CT virtual intravascular endoscopy in pre-aortic stent grafting: In vitro phantom study

OBJECTIVE

To investigate the optimal scanning protocol for multislice computed tomography angiography (MSCT) in pre-aortic stent grafting observed with virtual intravascular endoscopy (VIE).

MATERIALS AND METHODS

The study was performed on a human abdominal aortic phantom which was housed in a perspex container, filled with contrast medium having CT attenuation similar to that used in the patient's abdominal CT scan. A series of scans were performed on a four-slice multislice CT scanner with the scanning protocols as follows: section thickness of 1.3, 3.2 and 6.5 mm, pitch value of 0.875, 1.25 and 1.75 with reconstruction intervals of 50% overlap. The degree of stair-step artifacts was measured at three different locations, superior mesenteric artery (SMA), renal ostium and the normal abdominal aorta. Standard deviation (S.D.) of the signal intensity measured on surface shaded images was used to determine the image quality. Radiation dose was also recorded in each scanning protocol.

RESULTS

The VIE images showed that image quality was not dependent on pitch and section thickness in the visualization of renal ostium and SMA, whereas it was dependent on these two factors at the level of the normal aorta (p<0.05). It was noticed that when section thickness reached 6.5 mm the SMA and renal ostia became distorted. Radiation dose measured in 1.3 mm protocols was significantly higher that those measured in other section thicknesses (p<0.05).

CONCLUSION

The scanning protocol of section thickness 3.2 mm, pitch 1.25 with a reconstruction interval of 1.6 mm was recommended as it allows optimal visualization of VIE images of aortic ostia, generation of fewer artifacts and less radiation dose.

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.

Detection of Abdominal Aortic Aneurysm in Patients with Peripheral Artery Disease

OBJECTIVE

To describe the prevalence of abdominal aortic aneurysms (AAA) in patients with peripheral artery disease (PAD).

DESIGN

Observational, descriptive, transverse study.

PATIENTS AND METHODS

We performed an abdominal ultrasound in 1190 consecutive patients with lower limb chronic ischemia (1/99-12/04). We registered cardiovascular risk factors and clinical data for analysis.

RESULTS

The ultrasound was inconclusive in 24 (2%) patients; 1166 patients completed the study. They were mostly male (93.7%), with an age mean of 67+/-9.9 years (37.7-93.4). The main cardiovascular risk factors were: smoking (80.9%), hypertension (41.7%) and hypercholesterolemia (31.4%). The prevalence of AAA was 13% (n = 151). Only 1.5% (n = 17) of the patients had a large AAA (>5 cm). The AAA was clearly more prevalent in men (n = 148; 13.6%) than in women (n = 3; 4.1%) (RR 3.47; 95% CI 1.11-10.89; p = 0.02). The prevalence significantly increased with age, with a maximum of 17.1% in over 75-year-old men (p = 0.006). Patients with tibial disease had a significantly higher prevalence of AAA than aortoiliac or femoro-popliteal disease (p = 0.02).

CONCLUSIONS

The prevalence of AAA in patients with PAD is much higher than that reported in the general population. We recommend that an abdominal ultrasound be routinely included in the study of these patients. Over 75-year-old men are at particularly high-risk.

The value of screening in siblings of patients with abdominal aortic aneurysm

OBJECTIVES

This study aimed to determine the incidence of abdominal aortic aneurysm (AAA) in a large group of siblings of Australian AAA patients to determine if screening in this group is justified.

METHODS

1254 siblings of 400 index AAA patients were identified and offered aortic ultrasound screening. An age and sex matched control group was recruited from patients having abdominal CT scans for non-vascular indications. AAA was defined by an infrarenal aortic diameter of > or =3 cm or a ratio of the infrarenal to suprarenal aortic diameter of > or =2.0. A ratio of 1.0-1.5 was considered normal, and a ratio of >1.5 to <2.0 was considered ectatic. Aortic enlargement was defined as ectasia or aneurysm.

RESULTS

276 (22%) siblings could be contacted and agreed to screening or had previously been diagnosed with AAA. All 118 controls had normal diameter aortas. 55/276 siblings had previously been diagnosed with AAA. The remaining 221 siblings underwent ultrasound screening. Overall, 30% (84/276) had enlarged aortas (5% ectasia, 25% aneurysmal); 43% of male siblings (64/150) and 16% of females siblings (20/126). The incidence was 45% in brothers of female index patients, 42% in brothers of male patients, 23% in sisters of female patients, and 14% in sisters of male index patients.

CONCLUSIONS

The overall incidence of aortic enlargement of 30% found in this study warrants a targeted screening approach with ultrasound for all siblings of patients with AAA. A similar targeted approach for screening of the children of AAA patients would also seem advisable.

Screening for asymptomatic internal carotid artery stenosis and aneurysm of the abdominal aorta: comparing the yield between patients with manifest atherosclerosis and patients with risk factors for atherosclerosis only

OBJECTIVE

The purpose of this study was to investigate whether screening for internal carotid artery stenosis (ICAS) and aneurysm of the abdominal aorta (AAA) is indicated in patients with either manifest atherosclerotic disease or with only risk factors for atherosclerosis.

STUDY DESIGN

Data were obtained for 2274 patients enrolled in the SMART study, an ongoing single-center, prospective cohort study of patients referred to our vascular center with manifest atherosclerotic disease (peripheral atherosclerotic disease [PAD]; transient ischemic attack [TIA], stroke, or ICAS; AAA; angina pectoris; or myocardial infarction [MI]) or with only risk factors for atherosclerosis (diabetes mellitus, hypertension, hyperlipidemia). The presence of ICAS or AAA was determined with duplex scanning and ultrasonography.

RESULTS

The prevalence of ICAS 70% or greater is low in patients with risk factors for atherosclerosis only (1.8%-2.3%), intermediate in patients with angina pectoris or MI (3.1%), and highest in patients with PAD (12.5%) or AAA (8.8%). The prevalence of AAA 3 cm or larger is low in patients with risk factors for atherosclerosis only (0.4-1.6%), intermediate in patients with angina pectoris or MI (2.6%), and highest in patients with PAD (6.5%) or TIA, stroke, or ICAS (6.5%). The prevalence of AAA larger than 5 cm is low in all of the considered patient groups. The yield of screening can be optimized through selection on the basis of simple patient characteristics. In patients with PAD, selecting those with advanced age (>54 years) increased the prevalence of ICAS to 21.8%. Selecting patients with lower diastolic blood pressure (<83 mm Hg) increased the prevalence of ICAS to 17.9%. In patients with both advanced age and lower diastolic blood pressure, the prevalence of ICAS increased to 34.7%. Selecting patients with advanced age increased the prevalence of AAA 3 cm or larger to 9.6%. In patients with TIA, stroke, or ICAS, selecting those with advanced age increased the prevalence of AAA 3 cm or larger to 8.2%. Selecting patients with taller stature (>169 cm) increased the prevalence of AAA 3 cm or larger to 9.3%. In patients with advanced age and taller stature, the prevalence of AAA 3 cm or larger increased to 13.1%.

CONCLUSIONS

Screening for ICAS should be limited to patients referred with PAD or AAA, especially those with advanced age or with low diastolic blood pressure. Screening for AAA should be limited to patients referred with PAD or with TIA, stroke, or ICAS, particularly those with advanced age or tall stature. In patients referred with angina pectoris or MI and those referred with only risk factors for atherosclerosis, screening cannot be endorsed.

Distal aortic diameter and peripheral arterial occlusive disease

OBJECTIVE

Several studies have reported an association between abdominal aortic dilatation and peripheral arterial occlusive disease. Narrowing of aortic diameter, also called abdominal aortic hypoplasia, and peripheral arterial occlusive disease have received insufficient attention. Precise estimates of the relationship between aortic hypoplasia and peripheral arterial occlusive disease are lacking. In this study, we assessed the relationship between abdominal aortic diameter and peripheral arterial occlusive disease.

METHODS

In this cross-sectional study, we analyzed 1572 patients 18 to 79 years of age, newly referred to the vascular center of our hospital with clinically manifest atherosclerotic arterial disease or for treatment of cardiovascular risk factors. Diameter measurements were used to subdivide patients according to tertiles of abdominal aortic diameter. Peripheral arterial occlusive disease was assessed by adjusted Rose questionnaire, ankle-brachial pressure index, and the presence of gangrene or leg ulcers.

RESULTS

Compared with patients with normal aortic diameter, peripheral arterial occlusive disease was twice as prevalent in patients at both ends of the aortic diameter spectrum. When the lowest tertile was compared with the middle tertile in male patients, the adjusted odds ratio was 1.7 (95% CI, 1.0-3.1). When the highest tertile was compared with the middle tertile, the adjusted odds ratio was 2.1 (95% CI, 1.2-3.4). Similar results were found in female patients. The adjusted odds ratio of lowest versus middle tertile was 2.4 (95% CI, 1.1-5.0) and 1.8 (95% CI, 0.8-4.0) when the highest tertile was compared with the middle tertile.

CONCLUSION

The risk of peripheral arterial occlusive disease was increased in the lower and upper distribution of aortic diameter. Apparently, both patients with an aortic diameter too large and patients with an aortic diameter too small are prone to peripheral arterial occlusive disease. This is the first large study that shows that small aortic diameter is associated with peripheral arterial occlusive disease.

Evaluation of aneurysm models, particularly of the aorta and cerebral arteries

Irrespective of their intended use, the best models of spontaneous aneurysms in humans are produced under conditions analogous to those occurring in humans and specific for the site. Even if appropriate for other purposes, models dependent on artificial conditions (physical and thermal trauma, chemical and enzymatic degradative processes), not in compliance with the above, bear no relationship to the etiology or pathology of the lesion or disease under investigation. Surgical models of poststenotic dilatation and aneurysm, arteriovenous shunts, and venous graft aneurysms are suitable for study of the prevailing hemodynamics and pathological effects of the associated stresses on the vessel wall which have bearing on degenerative aneurysms at other sites. The protracted course of atherosclerosis and constraints of time and research funds when reproducing the pathology and conditions prevailing in the human situation legitimize the use of models which accelerate development and complications. The limitations of any model are of paramount consideration. The value of some current models of aortic and cerebral aneurysms is discussed.

Natural history of abdominal aortic aneurysm with and without coexisting chronic obstructive pulmonary disease

PURPOSE

To study the relation between abdominal aortic aneurysms and chronical obstructive pulmonary disease (COPD), in particular the suggested common elastin degradation caused by elastase and smoking.

METHODS

A cross-sectional population study and a prospective cohort study of small abdominal aortic aneurysms was performed in a community setting. All previous diagnoses recorded in a hospital computer database were received for 4404 men 65 to 73 years of age who had been invited to a population screening for abdominal aortic aneurysm. One hundred forty-one men had AAA (4.2%). They were asked to participate in an interview, a clinical examination, and collection of blood sample. Men with an abdominal aortic aneurysm 3 to 5 cm in diameter were offered annual ultrasound scans to check for expansion.

RESULTS

Among patients with COPD 7.7% had abdominal aortic aneurysms (crude odds ratio=2.05). The adjusted odds ratio, however, was only 1.59 after adjustment for coexisting diseases associated with abdominal aortic aneurysm (P=.13). The mean annual expansion was 2.74 mm per year among patients with COPD, 2.72 among patients without COPD, and 4.7 mm among patients who used oral steroids compared with 2.6 among patients who did not use steroids (P < .05). Concentration of serum elastin peptide and plasma elastase-alpha1-antitrypsin complexes correlated negatively with forced expiratory volume in the first second (FEV1) among patients with COPD. However, multivariate regression analysis showed that concentration of serum elastin peptide, therapy with beta-agonists, and FEV1 correlated positively with degree of expansion but that concentration of plasma elastase-alpha1-antitrypsin complexes and serum alpha1-antitrypsin did not influence expansion, suggesting that elastase plays an important role in the pathogenesis of COPD but not of abdominal aortic aneurysm.

CONCLUSION

The high prevalence of abdominal aortic aneurysm among patients with COPD is more likely to be caused by medication and coexisting diseases rather than a common pathway of pathogenesis.

The fate of patients undergoing surveillance of small abdominal aortic aneurysms

OBJECTIVES

Increasing numbers of patients with small abdominal aortic aneurysms (AAA) are being diagnosed. The aim of this paper is to define the fate of those patients undergoing surveillance of small AAAs.

SETTING

U.K. district general hospital.

METHODS

A prospective study has been carried out of all patients undergoing surveillance. At the time of the first consultation the patient was assessed, a Detsky score calculated and the referral source noted. End points of the study were elective repair of the aneurysm, aneurysm rupture or death of the patient.

RESULTS

Details of 267 patients were analysed. The referral source was general practitioner in 39%, patients with peripheral vascular disease in 32% and department of urology in 21%. None were referred from population screening. The cumulative 5-year risks of rupture, elective repair or non-AAA related deaths were 15%, 26% and 46% for all patients, 4%, 13% and 38% for patients initially presenting with AAA less than 4 cm diameter and 21%, 42% and 54% for patients presenting with an AAA 4-5.5 cm diameter. All but one of 11 patients whose aneurysm ruptured were unfit or had declined elective repair. There were 56 non-AAA related deaths, the majority due to cardiovascular causes. Those patients with low Detsky scores had a 5-year survival of 62%, those with high scores 44%. The age/sex matched survival or a normal population at 5 years in 80%.

CONCLUSION

Overall the non-AAA related mortality was greater than the risks of rupture or elective repair. It is important to bear in mind the poor prognosis of this group of patients compared with a normal population when considering elective repair of small AAAs.

Failure to demonstrate Chlamydia pneumoniae in symptomatic abdominal aortic aneurysms by a nested polymerase chain reaction (PCR)

OBJECTIVE

To investigate whether Chlamydia pneumoniae is present in symptomatic abdominal aortic aneurysms (AAA).

METHOD AND MATERIALS

After optimisation of DNA extraction procedures an inhibitor-controlled nested polymerase chain reaction (PCR) amplifying fragments of the gene encoding the C. pneumoniae specific major outer membrane protein was performed on 124 wall-specimens from 20 patients with symptomatic AAA.

RESULTS

None of the specimens contained C. pneumoniae-specific DNA. Minor inhibition of the PCR was noticed especially in media specimens.

CONCLUSION

Using a sensitive and specific nested PCR, we were not able to detect C. pneumoniae in symptomatic AAA. The failure to detect C. pneumoniae in symptomatic AAA, combined with previously reported positive findings in atherosclerotic lesions, supports the hypothesis that AAA and atherosclerosis might be two different disease entities.

A prospective survey of patients presenting with abdominal aortic aneurysm

OBJECTIVES

To define the presentation and management of patients presenting with abdominal aortic aneurysm (AAA) DESIGN AND SETTING: A prospective survey was carried out of all patients presenting to hospitals within the Oxford region.

MATERIALS AND METHODS

Data were collected by one surgeon in each hospital. Full details were collected onto data sheets.

RESULTS

One hundred and ninety patients presented, 141 electively, 46 with ruptured AAA and three with acute AAAs. In 53 patients presenting electively the aneurysm was small and surveillance started. Fifty-six patients underwent an operation, three patients died. Of 46 patients with a ruptured aneurysm 24 (52%) died. In 11 no operation was carried out and all of these patients died within 24 h. Operative mortality was 13 of 35 patients (37%). More patients with a ruptured AAA were transferred to the teaching hospital compared with a district general hospital (p < 0.05). This was reflected in a lower operative mortality in the teaching hospital.

CONCLUSIONS

The presentation of AAA in this study was approximately 15 per 100,000 population. Approximately one-third of patients presenting electively had small AAAs which required surveillance. A further third underwent an operation, the remaining patients being unfit. Approximately one-quarter of patients with a ruptured aneurysm did not undergo an operation. The operative mortality was 37%.

A prospective study to define the optimum rescreening interval for small abdominal aortic aneurysm

A prospective study of 99 patients with small abdominal aortic aneurysms was undertaken using serial ultrasound to assess the optimum screening interval. Fifty-three patients had aneurysms measuring 2.5-3.9 cm and 46 patients aneurysms of 4.0-4.9 cm. Aneurysms measuring 2.5-3.9 cm were screened annually and those > 4.0 cm every 6 months. There were eight deaths in the 2.5-3.9 cm group, none attributable to a ruptured aneurysm and five patients have had their aneurysm repaired. Nine patients died in the 4.0-4.9 cm group, one with a ruptured aneurysm measuring 5.6 cm at her previous screening visit and who was unfit for operation. No other patient had an aneurysm which ruptured between scans. There were seven elective repairs in this group. No patient died following elective operation in either group. The mean growth rate of aneurysms in the 2.5-3.9 cm group was 2.2 mm in the first year, 2.8 mm in the second and 1.8 mm in the third. Corresponding growth rates in the 4.0-4.9 cm group were 2.7 mm, 4.2 mm and 2.2 mm. This study supports a policy of annual screening for aneurysms measuring 2.5-3.9 cm and 6-monthly screening for those > or = 4.0 cm.

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.

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.

Surgical workload as a consequence of screening for abdominal aortic aneurysm

A study was performed to evaluate the surgical workload that has resulted from screening an at-risk population for abdominal aortic aneurysm (AAA) and to forecast the likely workload from an established screening programme. Over an 8-year period 8944 people aged 65-80 years were screened; 356 were found to have an AAA of 3 cm or greater in diameter. There were 288 outpatient consultations involving 171 patients, and 43 patients (4.8 per 1000 screened) had surgery during the study period. A fully operational screening programme for a population of 250,000, screening men and women at a rate of 2000 per year, would be expected to produce a surgical workload of nine or ten operations for AAA per year. Screening men only would increase this to 34 annually.

Ultrasonographic screening for abdominal aortic aneurysm in an urban community

As part of the Birmingham Community Aneurysm Screening Project, 3500 men aged 65-75 years from 20 urban general practices were invited for aortic ultrasonographic screening at their own general practitioner's surgery; 2669 (76.3 per cent) attended. Compliance rates varied between catchment areas, from 52.1 per cent for inner-city areas to 89.6 per cent for suburbs. Successful aortic imaging was achieved in 97.3 per cent of scans. Aortic diameter > 29 mm occurred in 219 patients (8.4 per cent) and 79 (3.0 per cent) with a diameter > 40 mm were referred for vascular surgical assessment; 140 patients with an aortic diameter of 29-40 mm are currently undergoing follow-up by serial ultrasonographic examinations at intervals of 3 months at their doctor's surgery. Risk factor analysis revealed ischaemic heart disease in 21.9 per cent of men with aneurysm, compared with 11.6 per cent in those without (P < 0.001); 18.3 per cent of men with aneurysm had had a previous myocardial infarction and 13.2 per cent had peripheral vascular disease, compared with 7.4 per cent (P < 0.001) and 8.0 per cent (P < 0.01) respectively of those without. No association was found between aneurysm and hypertension or diabetes. Community-based aortic screening is an inexpensive, effective method of diagnosis of aneurysm, with high compliance from the at-risk cohort of an urban population. Such screening programmes may help to reduce the mortality rate from aortic aneurysm rupture.