Morphometric analysis of anatomic variables affecting endovascular stent design in patients undergoing elective and emergency repair of endovascular abdominal aortic aneurysm

The Division of Vascular Surgery, St. Michael's Hospital, University of Toronto, Toronto, Ont.
Canadian journal of surgery. Journal canadien de chirurgie (Impact Factor: 1.51). 02/2010; 53(1):25-31.
Source: PubMed


Our objective was to identify morphologic trends in elective and emergency endovascular aneurysm repair (EVAR). This work will inform hospitals with endovascular programs about the diameters and lengths of endostents that should be available to efficiently care for patients with these conditions.
We performed a retrospective review of patients undergoing elective (n = 127) and emergency (n = 17) EVAR. Using computed tomography and 3-dimensional reconstructions, we evaluated the following: diameters of the aneurysm (D3), the aorta at the superior mesenteric (D1) and renal (D2a,b,c; 3 levels) levels, the iliac arteries (D5a,b; right and left) and the aortic bifurcation (D4); lengths from the lowest renal artery to the distal aspect of the aortic neck (H1), to the aortic bifurcation (H3), to the right and left iliac bifurcations (H4a,b); and angles of the origin of the common iliac arteries on the transverse plane (A1). We used descriptive statistics of trends within groups and independent sample t tests.
In elective and emergency aneurysm repair, D2max (26, standard deviation [SD] 3, mm v. 30.7 [SD 3] mm), D5a (16 [SD 4.7] mm v. 19.3 [SD 5] mm), D5b (15.3 [SD 4] mm v. 18.1 [SD 3.6] mm), H1 (25.6 [SD 8.6] mm v. 18 [SD 2] mm), H4a (173 [SD 22] mm v. 189.5 [SD 22] mm) and H4b (174 [SD 25] mm v. 190 [SD 14] mm) were significantly different between the 2 groups (p = 0.001, p = 0.006, p = 0.007, p < 0.001, p = 0.05 and p = 0.01, respectively). H3 (118 [SD 17] mm v. 121.5 [SD 13.5] mm) was not significantly different (p = 0.40). In elective patients, A1 identified the right common iliac more frequently anterior relative to the left common iliac (mean 23 degrees , SD 16 degrees).
Significant anatomic differences between elective and emergency patients will require hospitals to stock separate endovascular devices to treat abdominal aortic aneurysms in both groups.

Download full-text


Available from: Wilfred Dang, Oct 19, 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: Die Computertomographie-Angiographie (CTA) der Aorta ist als diagnostisches Standardverfahren zur präprozeduralen Evaluation und Planung der endovaskulären Versorgung abdomineller Aortenaneurysmen („endovascular aortic repair“, EVAR) akzeptiert. Dabei liefert die CTA alle relevanten anatomischen und morphologischen Informationen über die zugrundeliegende Pathologie der Aorta und der Beckenachsen. Verschiedene Softwarelösungen zur multiplanaren Rekonstruktion der CT-Daten stehen für die exakte Vermessung der Zugangswege und der Landungszonen zur Verfügung und sind essenzieller Bestandteil der individuellen Operationsplanung. Die Synthese sämtlicher CT-basierter Informationen ermöglicht eine sichere und zielgenaue Freisetzung des Stentgrafts in der Aorta. Ferner kann die periprozedurale Strahlendosis durch eine präzise präoperative Planung der Durchleuchtungspositionen bei der Implantation reduziert werden.
    No preview · Article · Jun 2013 · Der Radiologe
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: DynaCT(®) is a method for obtaining computed tomography (CT)-like images using a C-arm system. Our aim was to compare the accuracy of these images to multidetector CT (MDCT) images prior to endovascular aortic repair (EVAR). A non-consecutive group of 20 elective patients were prospectively exposed to MDCT and one additional DynaCT before EVAR. Six arterial measurements and nine anatomical areas were chosen to: (1) visualise the peri-aortic soft tissue and assess the possibility to diagnose a potential haemorrhage from a ruptured aneurysm and (2) make the pre-treatment measurements before insertion of stent graft. Differences between modalities and readers were statistically compared using a linear mixed model. For maximum aortic diameter, a significant difference of 1.3 mm was found between techniques (p = 0.043). Visibility scores were significantly better for all areas in MDCT data. Pre-treatment evaluation with DynaCT before EVAR was possible for all areas; evaluation of the iliac arteries were suboptimal due to a limited imaging volume size. Significant inter-reader differences were found for all anatomical areas. The result indicates that DynaCT gives sufficient information to determine the correct treatment and for selecting the proper stent graft before EVAR. A limited volume size reduces the evaluation of the iliac arteries.
    Full-text · Article · Sep 2011 · European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objectives: The aims of this study were to evaluate the morphometric and structural characteristics of abdominal aortic aneurysms (AAA), and to form a morphometric model of the AAA that could be applicable in the development of mathematical and computation models for rupture risk assessment. Material and Methods: The following morphometric parameters significant for biomechanical stability and compliance of the aortic wall were analyzed: the thickness of the wall, the thickness of the media and the thickness of the adventitia. Morphometry was performed with the Olympus BX 41 microscope and the Olympus C – 5060 wide zoom digital camera with an application of the Olympus DP-soft Image Analyzer program. The media-to-wall and adventitia-to-wall ratios were calculated. Parameters were correlated with the diameters of the aneurysms (established by MSCT angiography), the patients’ age and gender, the presence of a thrombus and the grade of inflammation. Results and Discussion: Our results showed that an increase in the AAA diameter affected the structure of the aortic wall in the following ways: 1. the thickness of the aortic wall significantly increased, with the greatest increase for aneurysms with diameters between 41 and 60 mm (ANOVA F=268.561; p<0.001); 2. the thickness of the adventitia and its proportion in the wall thickness significantly increased, in the same group (ANOVA F=376.727, p<0.001); 3. the thickness of the media and its proportion in the wall thickness significantly decreased, with the greatest increase for aneurysms with diameters >60mm (ANOVA F=265.865; p<0,001). The supposed influence of the latter two factors reduced the adaptability of the vascular wall and augmented the rupture risk since the aortic wall media is responsible for the elastic properties of the blood vessels, while increased and fibrotic adventitia did not provide sufficient compliance. We confirmed, by means of the Univariate Analysis of Variance, that the increase of the adventitia and destruction of the media were even greater in aneurysms with inflammation and in patients over 65 years old. Female patients with small aneurysms (d<40mm) are at a special rupture risk. They have a significantly thinner wall (F=35.164; p<0.001), with a significantly thinner media (F=35.473; p<0.001) and a significantly thicker adventitia (F=21.146; p<0.001) than male patients. Small-diameter aneurysms with a thrombus are also under special rupture risk. Destruction of the media was advanced in this group, with an exceptionally small medial thickness compared to larger aneurysms with a thrombus (F=237.770; p<0.001). Conclusions and Clinical Relevance: A correction of AAA computation models with histomorphometric data is necessary for an accurate prediction of rupture risk. Parameters used in computation models are based on CT scans, but not all parameters are easily assessed with a CT scan (i.e., the wall thickness). Most of the computation models operate under the assumption that aneurysms are homogenous structures, which is not the case. On the contrary, aneurysms are heterogeneous, with extreme variations of structure among patients and in different parts of the same aneurysm. Some data are not uniquely defined and recognized, (i.e., the influence of a thrombus on the wall structure). Hence, the goal of morphometric models is to provide sufficient data for the construction of an improved and adjustable model for rupture risk prediction that will combine many different factors and enable a tailored decision making process for each patient.
    No preview · Chapter · Jan 2013
Show more