Pre-operative classification of abdominal aortic aneurysms with spiral CT: the axial source images revisited

Can the Fenestrated Anaconda™ salvage failed competitor endografts? An international frame of reference

INTRODUCTION

An abdominal aortic aneurysm (AAA) is a life-threatening abnormal dilation of the abdominal aorta that can be repaired either endovascularly or with open surgery. However, endovascular aortic repair (EVAR) has become the main treatment modality for AAA due to its more optimal results. EVAR devices can either be standard, fenestrated, or branched, with fenestrated EVAR (FEVAR) seemingly achieving superior prospects. Although EVAR is associated with excellent outcomes, it still carries a risk of certain complications requiring reintervention or 'rescue'. Several commercial EVAR devices are available on the global market, nevertheless, the Fenestrated Anaconda developed by Terumo Aortic can be considered the superior device due to the wide range of endovascular solutions that it offers along with its unique custom-made approach, excellent results and its highly promising potential to be used as a 'rescue' device for failed competitor endografts.

MATERIALS AND METHODS

The current study represents a 9-year cross-sectional international analysis of a custom-made Fenestrated Anaconda™ device. For the statistical analysis, SPSS 28 for Windows and R were utilised. Pearson Chi-square analysis was used to assess differences in cumulative distribution frequencies between select variables. Statistical significance for all two-tailed tests was set at p < 0.05.

RESULTS

Out of 5058 EVARs performed using the Fenestrated Anaconda, 2987 (59%) were 'rescue' procedures for migrated Gore (n = 252) and Medtronic (n = 2735) devices. The Fenestrated Anaconda™ was indicated as the reintervention device either due to unsuitable/complex anatomy for the competitor (n = 2411) or based on surgeon preference (n = 576). Overall, the Fenestrated Anaconda was utilised to rescue 3466 (68.5%) failed previous EVARs using competitor devices. Yet, the primary endovascular solution offered by the Fenestrated Anaconda was FEVAR (91.3%), with 112 (2.2%) devices using custom-made iliac stents.

DISCUSSION

The use of the Fenestrated Anaconda endograft as a 'rescue' device to salvage failed competitor devices is well-established in the literature with excellent clinical outcomes achieved. The evidence in the literature also highlights the distinctive custom-made approach that the Fenestrated Anaconda offers which enables it to treat extremely complex aortic anatomy.

Patient longevity and survival with custom-made endovascular solutions: The Fenestrated AnacondaTM approach

BACKGROUND

Endovascular aortic repair (EVAR) has become the mainstay treatment for abdominal aortic aneurysms and is associated with excellent clinical outcomes. However, there remains a risk of complications requiring reintervention. Several EVAR devices exist commercially, yet, the Terumo Aortic Fenestrated Anaconda™ has demonstrated outstanding results. The main scope of this study is to evaluate survival/longevity, target vessel patency (TVP), endograft migration and reintervention following Fenestrated Anaconda™ implantation and discuss relevant literature.

METHODS

The current study represents a 9-year cross-sectional international analysis of custom-made Fenestrated Anaconda™ device. For the statistical analysis, SPSS 28 for Windows and R was utilised. Pearson Chi-Square analysis was used to assess differences in cumulative distribution frequencies between variables. Statistical significance for all two-tailed tests was set at p < 0.05.

RESULTS

A total of 5058 patients received the Fenestrated Anaconda™ endograft. The Fenestrated Anaconda™ was indicated either due to complex anatomy for competitor devices (n = 3891, 76.9%) or based on surgeon preference (n = 1167, 23.1%). Both survival and TVP were 100% during the first 6 postoperative years but dropped to 77.1% and 81% thereafter. In the complex anatomy indication group, cumulative survival and TVP were both 100% until year 7 post-EVAR when they decreased to 82.8% and 75.7%. In the other indication group, survival and TVP were also 100% during the first 6 years but plateaued at 58.1% and 98.8% in years 7-9 of follow-up. No cases of endograft migration and reintervention were recorded.

CONCLUSION

The Fenestrated Anaconda™ has been proven across the literature to be a highly effective EVAR endograft, as it has demonstrated excellent survival/longevity and TVP as well as minimal endograft migration and reintervention.

Abdominal aortic aneurysm and omega-3 polyunsaturated fatty acids: Mechanisms, animal models, and potential treatment

Abdominal aortic aneurysm (AAA) is an inflammatory disease associated with macrophage accumulation in the adventitia, oxidative stress, medial elastin degradation and aortic dilation. Progression of AAA is linked to increased risk of rupture, which carries a high mortality rate. Drug therapies trialled to date lack efficacy and although aneurysm repair is available for patients with large aneurysm, peri-surgical morbidity and mortality have been widely reported. Recent studies using rodent models of AAA suggest that long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) and their metabolites can moderate inflammation and oxidative stress perpetuated by infiltrating macrophages and intervene in the destruction of medial elastin. This review examines evidence from these animal studies and related reports of inhibition of inflammation and arrest of aneurysm development following prophylactic supplementation with LC n-3 PUFAs. The efficacy of LC n-3 PUFAs for management of existing aneurysm is unclear and further investigations involving human clinical trials are warranted.

Diagnostic value of CT virtual intravascular endoscopy in aortic stent-grafting

PURPOSE

To investigate the diagnostic value of postprocessing techniques for 3-dimensional (3D) computed tomography (CT), with emphasis on CT virtual intravascular endoscopy (VIE), in patients with abdominal aortic aneurysms (AAA) treated with suprarenal stent-grafts.

METHODS

The preprocedural and postprocedural CT datasets from 47 AAA patients (40 men; mean age 75 years, range 61-87) undergoing aortic stent-grafting with suprarenal fixation were examined. The CT datasets were processed to create various 3D reconstructions: shaded surface display (SSD), maximum intensity projection (MIP), and VIE. Three independent radiologists assessed various diagnostic parameters for each 3D reconstruction method and compared them to axial CT images.

RESULTS

Scores for VIE reconstructions were inferior to axial CT images in the visualization of normal arterial branches, measurement of the aneurysm diameter and neck length, as well as assessment of vessel patency and presence of endoleaks. VIE was rated superior to axial CT and other 3D imaging methods in visualizing the configuration of stent struts relative to the aortic branch ostia and the number of stent wires crossing the ostia in >80% of cases.

CONCLUSIONS

VIE was not found to play a role in most preoperative situations compared to axial CT images. However, VIE provided additional postgrafting information on the 3D relationship of the suprarenal stent struts to the aortic branch ostia (in particular the renal and superior mesenteric arteries). VIE findings might aid clinicians in accurately assessing the effect of suprarenal stent-grafting on the renal arteries.

Imaging of aortic aneurysms and dissection: CT and MRI

There are numerous approaches to the diagnosis of aortic aneurysms and aortic dissection. Echocardiography, computed tomography (CT), and magnetic resonance imaging (MRI) have enthusiastic proponents promoting each technique, which to some extent obscures the real value of each technique. This review examines the role of these techniques in the diagnosis of aortic disease, with special reference to the most recent published literature and an emphasis on the use of CT and MRI. For most patients with chronic aortic disease, MRI is the most appropriate investigation. In acute situations, CT scanning is usually the most useful technique, with echocardiography added for those with ascending aortic disease or cardiac complications.

Inflammatory abdominal aortic aneurysms: diagnosis with gadolinium enhanced T1-weighted imaging

AIM

Inflammatory abdominal aortic aneurysms (IAAA) are a variant of abdominal aortic aneurysms, which are associated with an increased morbidity. The diagnosis of IAAA has traditionally been established with a combination of clinical and laboratory findings together with contrast enhanced CT. There is a high incidence of renal impairment in this group, and therefore contrast enhanced CT may be harmful.

PATIENTS AND METHODS

Five patients with IAAA underwent T1-weighted spin echo and gradient echo gadolinium enhanced abdominal MRI. A total of eight examinations were performed, including three patients who underwent repeat MRI following steroid therapy.

RESULTS

The inflammatory cuff was clearly identified following gadolinium administration in all eight examinations. The cuff enhanced homogeneously in all patients with no alteration in appearance following steroid therapy. The intravenous administration of gadolinium DTPA enabled clearer definition of locally involved structures.

CONCLUSION

Gadolinium enhanced MRI readily demonstrates features of IAAA. In view of potential renal impairment in this patient group, we recommend this technique in preference to contrast enhanced CT in the initial investigation of inflammatory abdominal aortic aneurysms.

Functional renal perfusion imaging with colour mapping: is it a useful adjunct to spiral CT of in the assessment of abdominal aortic aneurysm (AAA)?

AIM

To ensure optimal timing with pre-operative spiral CT for abdominal aortic aneurysms (AAA), an initial 'timing' single level CT is commonly performed with a small bolus of contrast. This can be exploited to obtain adjunct functional information on renal perfusion. We have investigated the potential of this to measure renal perfusion, to produce colour renal perfusion maps and to predict surgical outcome in infrarenal aortic aneurysm assessment.

METHODS

We studied 21 patients being assessed for repair of infrarenal AAA. Prior to the spiral CT, a single level through the renal hili and aorta was scanned after the intravenous injection of 25 ml of contrast given at 10 ml/s. Ten 1 s duration scans were performed from 8 to 30 s after injection. Optimal timing for CT angiography can then be determined. Time-density curves were then drawn for both kidneys and aorta using regions of interest (ROIs) or pixel-by-pixel analysis. Renal cortical perfusion was measured using both ROI analysis and pseudocolour perfusion images. Following previous work, perfusion was calculated as the peak upslope of the tissue time density curve divided by peak aortic enhancement.

RESULTS

Cortical mean perfusion averaged 2.48 ml/min per ml (range 0.8-3.7 ml/min per ml n = 34) and the values obtained agreed with literature expectations. Follow up in the 10 patients proceeding to AAA repair suggest low mean perfusion values and predict a raised postoperative creatinine (P < 0.05)

CONCLUSIONS

Additional functional data and imaging can be obtained from the initial timing scan of a CT study, without requiring a dedicated study.