New insights into inflammatory abdominal aortic aneurysms

Mid-term clinical outcomes and morphological changes after endovascular aneurysm repair of inflammatory abdominal aortic aneurysms: a single-center experience

BACKGROUND

Endovascular aneurysm repair (EVAR) has been suggested as treatment for inflammatory abdominal aortic aneurysms (IAAA), but the actual clinical and radiological outcomes need to be evaluated.

PURPOSE

To report morphological changes in EVAR of IAAAs.

MATERIAL AND METHODS

Ten male patients (mean age, 67 years; range, 54-78 years) with IAAA were treated with EVAR using endovascular stent-grafts between March 2001 and January 2012. We retrospectively compared computed tomography angiography (CTA) images taken immediately (30 days after the EVAR), short-term (up to 1 year), and mid-term (beyond 1 year) to CTA images taken before the EVAR. Clinical success was defined as successful deployment of the stent-graft without a type I or III endoleak. Morphologic responses of IAAA to EVAR were reviewed by measuring the changes in aneurysm sac maximum diameter (mm), periaortic fibrosis (PAF) thickness (mm), and PAF enhancement (Hounsfield units [HU] on delayed CTA) on serial images.

RESULTS

Ten IAAA patients treated with EVAR were followed for a mean of 42 months (range, 7-129 months). No aneurysm-related deaths were observed during the follow-up of 10 patients. Primary clinical success was achieved in seven patients, assisted primary clinical success in one patient, and secondary clinical success in two patients. Aneurysm sac maximum diameter decreased in all patients (mean percentage reduction of 7.6%, 8.5%, and 17.3% in immediate, short-term, and mid-term follow-up CTA, respectively). PAF thickness decreased in eight patients (10.4%, 16.8%, and 27.2% regression upon follow-up). PAF enhancement decreased in nine patients and increased in one patient (mean percentage decrease of 13.0%, 27.3%, and 40.8% upon follow-up).

CONCLUSION

Treatment of IAAA with EVAR was effective and reduced aneurysmal sac diameter and the extent of PAF with acceptable morbidity.

Inflammatory Abdominal Aortic Aneurysm

We report a case of an abdominal aortic aneurysm (AAA) that underwent inflammatory transformation which we treated medically with corticosteroids. Medical therapy resulted in resolution of presenting symptoms and observed inflammatory changes. We review the clinical features, associated pathology, diagnostic, and therapeutic options in the management of inflammatory AAA.

Increased natural killer cell activity in patients with an abdominal aortic aneurysm

BACKGROUND

Natural killer (NK) cells have an emerging role in the development of chronic disease and in the direction and maintenance of inflammatory responses. Abdominal aortic aneurysms (AAA) is a chronic inflammatory disorder of unknown aetiology. The aim was to investigate whether NK cells showed altered function in patients with an AAA.

METHODS

The presence, phenotype and function of peripheral blood and tissue NK cells from patients with an AAA, peripheral vascular disease (PVD) and healthy age-sex-matched controls were assessed before and after surgery.

RESULTS

Patients with an AAA had significantly higher (P < 0.010) percentages of peripheral blood NK cells (mean (95 per cent c.i.) 23.8 (2.6) per cent) than patients with PVD (17.4 (2.9) per cent) and control subjects (16.2 (2.8) per cent). The NK cells from patients with an AAA had increased cytotoxicity on a per cell basis towards both an NK-sensitive target cell line and human aortic smooth muscle cells. Increased NK cell proportions (22.7 (3.5) per cent) and cytotoxic activity, together with higher C-reactive protein values, persisted after successful AAA repair.

CONCLUSION

These data support the hypothesis that increased NK cytotoxicity could be a contributing factor in the generation or potentiation of inflammation in patients with an AAA.

Analysis of Sequence Variations in the ABCC6 Gene among Patients with Abdominal Aortic Aneurysm and Pseudoxanthoma Elasticum

Abdominal aortic aneurysm (AAA) is characterized by dilatation of arterial walls, which is accompanied by degradation of elastin and collagen molecules. Biochemical and environmental factors are known to be relevant for AAA development, and familial predisposition is well recognized. A connective tissue disorder that is also associated with fragmentation of elastic fibers is Pseudoxanthoma elasticum (PXE). PXE is caused by mutations in the ABCC6 gene and mainly affects dermal, ocular and all vascular tissues. To investigate whether variations in ABCC6 are found in AAA patients and to determine mutations in PXE patients, we analyzed seven selected ABCC6 exons of 133 AAA and 54 PXE patients subjected to mutational analysis. In our cohort of AAA patients, we found five ABCC6 alterations, which result in missense or silent amino acid variants. The allelic frequencies of these sequence variations were not significantly different between AAA patients and healthy controls. Therefore, we suggest that alterations in ABCC6 are not a genetic risk factor for AAA. Mutational screening of the PXE patients revealed 19 different ABCC6 variations, including two novel PXE-causing mutations. These results expand the ABCC6 mutation database in PXE.

Results of Endovascular Repair of Inflammatory Abdominal Aortic Aneurysms. A Report from the EUROSTAR Database

OBJECTIVES

To investigate the results following endovascular treatment of patients with inflammatory abdominal aortic aneurysms (IAAA).

DESIGN

Retrospective study based on the EUROSTAR registry.

MATERIAL AND METHODS

Patients included in the EUROSTAR registry with IAAA (n=52, 1.4%) were compared to those having aneurysms without aortic fibrosis (n=3613, 98.6%). The mean follow-up period in patients with IAAA was 23 months (range 1-60). In 11 of the patients detailed information on the effect of endovascular repair and perianeurysmal fibrosis and ureteral entrapment was obtained by a dedicated questionnaire.

RESULTS

Twelve patients (23%) with IAAA had preoperative impairment of renal function and five had known hydronephrosis. Variables that were significantly associated with IAAA included younger age (p<.0001, mean difference 5.9, CI 3.7-7.9) and lower pulmonary risks score (OR 0.38, CI 0.19-0.74). At completion of the endovascular procedure, device stenosis was more frequently observed in patients with IAAA (OR 18.1, CI 3.52-93.0). There were no differences with regard to the rates of mortality, rupture or conversion in patients with IAAA and controls. In the majority, the aneurysm size regressed irrespective of nature of aneurysm. Of the 11 patients with a detailed assessment three had deterioration of renal function and three still had ureteral entrapment during follow-up.

CONCLUSION

Despite persistence of perianeurysmal inflammation in a proportion of patients operative and midterm results of endovascular repair were comparable in the patients with inflammatory and standard AAA.

Vascular inflammation and percutaneous transluminal angioplasty of the femoropopliteal artery: association with restenosis

PURPOSE

To determine the association of pre- and postprocedural serum levels of C-reactive protein (CRP), serum amyloid A (SAA), and fibrinogen at 6-month evaluation of restenosis after percutaneous transluminal angioplasty (PTA) of the femoropopliteal artery.

MATERIALS AND METHODS

In a prospective cohort study, 172 consecutive patients with peripheral artery disease of Fontaine stage IIa, IIb, or III who underwent successful PTA of the superficial femoral and popliteal arteries were included. Patency at 6 months was evaluated by using oscillography, ankle-brachial index, and color-coded duplex ultrasonography. The association of restenosis and CRP, SAA, and fibrinogen levels at baseline, 24 hours, and 48 hours after intervention was assessed by means of multivariate analysis with adjustment for known risk factors for restenosis.

RESULTS

Restenosis was found in 56 patients (33%) within 6 months. CRP values at baseline (adjusted odds ratio, 2.2; 95% CI: 1.1, 4.2) and 48 hours after intervention (adjusted odds ratio, 2.3; 95% CI: 1.6, 3.1) were independently associated with 6-month restenosis. SAA and fibrinogen values at any time interval were not significantly associated with patency in the multivariate models.

CONCLUSION

The extent of vascular inflammation as measured by means of acute-phase reactants before and after PTA of the femoropopliteal artery is associated with 6-month restenosis. Baseline and 48-hour CRP levels were independent predictors of postangioplasty outcome.

Acute phase reactants in patients with abdominal aortic aneurysm

BACKGROUND

There is increasing evidence that an inflammatory process is present in abdominal aortic aneurysms (AAAs) to varying degrees. The aim of this study was to compare acute phase reactants in patients with asymptomatic AAA, symptomatic AAA without rupture and ruptured AAA.

METHOD

Two hundred and twenty-five consecutive patients treated because of AAA were included in this case-control study. Polynomial logistic regression analysis was applied to compare admission C-reactive protein (CRP) and white blood count (WBC) measured in 111 asymptomatic outpatients, 52 symptomatic patients without rupture and 62 patients with rupture of the aneurysm. We adjusted for the potentially confounding effect of age, sex, haemoglobin levels and aneurysm diameter.

RESULTS

Patients with symptomatic AAA and patients with ruptured AAA had significantly elevated CRP (p=0.002) and WBC (p<0.0001) levels compared to asymptomatic patients. There was no statistically significant difference in CRP and WBC between patients with symptomatic AAA and ruptured AAA. Median CRP values of asymptomatic, symptomatic and ruptured AAA were <0.5 (interquartile range (IQR) <0.5-0.85), 1.1(IQR <0.5-4.0) and 2.4 mg/dl (IQR 0.65-8.6), respectively, and median WBC values were 6.5 (IQR 5.5-8.0), 8.7 (IQR 6.8-11.2) and 13.2 (IQR 10.5-17.0), respectively.

CONCLUSION

A significant elevation of CRP and WBC could be found in patients who presented with symptoms or rupture of an AAA. These indicators of inflammation were not observed in asymptomatic patients with AAA.

Heme oxygenase-1 gene promoter polymorphism is associated with abdominal aortic aneurysm

OBJECTIVE

Vascular inflammation is a hallmark in the development of abdominal aortic aneurysms (AAA). Heme oxygenase-1 (HO-1) is a novel vascular anti-inflammatory factor. A (GT)(n) dinucleotide repeat in the HO-1 gene promoter shows a length polymorphism that modulates the level of gene transcription. Short (< 25 GT) repeats are associated with an increased HO-1 upregulation in response to inflammatory stimuli than are longer repeats. We hypothesised that patients with AAA had less frequently short repeats in the HO-1 gene promoter compared to patients with coronary (CAD) or peripheral artery disease (PAD), or healthy controls.

METHODS

70 consecutive patients with atherosclerotic AAA, each 70 age- and sex-matched patients with CAD and PAD as well as 61 unmatched healthy atherosclerosis-free controls for a total of 271 individuals were studied. The frequency of carriers of short repeats in the HO-1 gene promoter was determined and compared between the groups.

RESULTS

In the AAA group, 29 patients (41%) were carriers of short (GT)(n) repeats compared to 47 patients (67%) in the CAD group, 44 patients (63%) in the PAD group and 35 healthy controls (59%). Patients with AAA were less frequently carriers of short repeats compared to age- and sex-matched patients with CAD (OR = 0.38, p = 0.006) and PAD (OR = 0.35, p = 0.01). Healthy controls exhibited short alleles more frequently than patients with AAA (p = 0.04), but comparable to CAD (p = 0.3) and PAD patients (p = 0.7).

CONCLUSION

Patients with AAA were less frequently carriers of short (< 25 GT) repeats in the HO-1 gene promoter than patients with atherosclerosis or healthy subjects. This suggests that short alleles, and thus, facilitated upregulation of HO-1, may be a protective anti-inflammatory factor against the development of AAA.

Restenosis after percutaneous transluminal angioplasty in the femoropopliteal segment: the role of inflammation

PURPOSE

To determine the value of baseline C-reactive protein (CPR), fibrinogen, and white blood cell (WBC) counts in predicting 1-year patency after percutaneous transluminal angioplasty (PTA) in the femoropopliteal segment.

METHODS

In a retrospective cohort study, 168 consecutive patients (103 men; median age 70 years, interquartile range 61-77) who underwent successful PTA of the femoral and/or popliteal arteries were analyzed. Twelve-month patency was evaluated using oscillography, ankle brachial index, duplex sonography, and angiography. The predictive value of inflammatory markers was assessed in a multivariate model controlling for cardiovascular risk factors, technical success, and hemodynamic factors.

RESULTS

Transient WBC elevation was found 6 hours after PTA, but this returned to baseline after 24 hours. Fibrinogen was elevated at 24 hours. Duplex scanning disclosed restenosis in 66 (39%) patients within the first 12 months after PTA. Only residual postdilation stenosis (> or = 30%) in the target segment (odds ratio 3.6, p=0.001) and baseline CRP levels (odds ratio 4.2, p=0.02) were independent predictors of outcome; neither WBC counts nor fibrinogen levels at any time point was associated with restenosis.

CONCLUSIONS

Primary technical success and postinterventional hemodynamic flow at the dilated segment seem to be more important for intermediate-term patency than atherogenic risk factors. The predictive value of preprocedural serum CRP levels on restenosis should be further investigated.

Abdominal aortic aneurysm: association between haptoglobin phenotypes, elastase activity, and neutrophil count in the peripheral blood

To investigate the role of genetic factors on susceptibility to atherosclerotic arterial disease, the influence of haptoglobin phenotypes (Hp) on serum elastase activity, neutrophil count, and elastin concentration in the aorta was measured in patients with abdominal aortic aneurysm (AAA; n=52) and aortoiliac atherosclerotic occlusive disease (AOD; n=37). Findings (serum elastase activity, peripheral blood neutrophil count) were compared to a control group (CG) of 37 subjects without atherosclerosis. Hp phenotyping performed by starch-gel electrophoresis produced a haptoglobin-hemoglobin complex of three phenotypes: Hp1-1, Hp2-2, and Hp2-1. Distribution of Hp phenotypes was similar in the three study groups (AAA, AOD, CG). Significant increases in serum elastase activity and neutrophil count was measured in Hp2-1 phenotype of AAA patients. Although the aorta wall of aneurysm patients contained less (p<0.001) elastin than that of AOD patients, no significant difference of aorta elastin concentration between the three Hp phenotypes, including Hp2-1, was measured. The postulated association of AAA susceptibility with Hp2-1 phenotype was supported by the study data that demonstrated an increase in serum elastase activity in patients undergoing AAA repair.

Inflammatory aneurysms of the abdominal aorta involving the ureters: is combined treatment really necessary?

PURPOSE

Peri-aneurysmal fibrosis complicating inflammatory aneurysm of the abdominal aorta may involve the ureters, causing urological complications. We assessed patient anatomical and clinical outcomes after conservative ureteral management.

MATERIALS AND METHODS

From the operative records of 1,271 consecutive patients who underwent surgical repair of abdominal aortic aneurysms from 1980 to 1999 we identified 77 (6%) who had inflammatory aneurysms, which were complicated in 19 (24.6%) by dense peri-aneurysmal and ureteral fibrosis. Of these 19 patients 15 (78.9%) had coexisting monolateral hydronephrosis, 3 (15.7%) had bilateral hydronephrosis and 1 (5.2%) had renal atrophy. In 14 cases (73.6%) the fibrotic reaction severely impaired renal function. Only 1 patient underwent an emergency operation, while the others underwent elective repair. Only 2 patients (10.5%) underwent a specific urological procedure, including bilateral nephrostomy in 1 and ureterolysis plus ureterolithotomy in 1. Most ureteral complications were treated conservatively by aneurysmectomy only.

RESULTS

Immediate postoperative mortality was 7% (1 of 14 cases). Median followup was 48 months. In 1 of the 13 cases (7.7%) a ureteral stent was placed during followup. After aneurysmectomy in 9 of the 12 patients (75%) with renal dysfunction periaortic fibrosis disappeared or decreased as well as associated hydronephrosis. In 11 of the remaining 12 patients (91%) of the 14 with renal failure preoperatively kidney function returned to normal or improved. In the 2 patients who underwent a specific urological procedure renal function improved but did not return to normal.

CONCLUSIONS

Inflammatory abdominal aortic aneurysms involving the ureters and compressing the urinary structures respond well to aneurysmal resection only without a urological procedure.