Browsing by Author "Davidovic, L. (7006821504)"

Objectives: The study aimed to identify differences and compare anatomical and biomechanical features between elective and ruptured abdominal aortic aneurysms (AAAs). Methods: Data (clinical, anatomical, and biomechanical) of 98 patients with AAA, 75 (76.53%) asymptomatic (Group aAAA) and 23 (23.46%) ruptured AAA (Group rAAA), were prospectively collected and analyzed. Anatomical, morphological, and biomechanical imaging markers like peak wall stress (PWS) and rupture risk equivalent diameter (RRED), comorbid conditions, and demographics were compared between the groups. Biomechanical features were assessed by analysis of Digital Imaging and Communication in Medicine images by A4clinics (Vascops), and anatomical features were assessed by 3Surgery (Trimensio). Binary and multiple logistic regression analysis were used and adjusted for confounders. Accuracy was assessed using receiving operative characteristic (ROC) curve analysis. Results: In a multivariable model, including gender and age as confounder variables, maximal aneurysm diameter [MAD, odds ratio (OR) = 1.063], relative intraluminal thrombus (rILT, OR = 1.039), and total aneurysm volume (TAV, OR = 1.006) continued to be significant predictors of AAA rupture with PWS (OR = 1.010) and RRED (OR = 1.031). Area under the ROC curve values and correct classification (cc) for the same parameters and the model that combines MAD, TAV, and rILT were measured: MAD (0.790, cc = 75%), PWS (0.713, cc = 73%), RRED (0.717, cc = 55%), TAV (0.756, cc = 79%), rILT (0.656, cc = 60%), and MAD + TAV + rILT (0.797, cc = 82%). Conclusion: Based on our results, in addition to MAD, other important predictors of rupture that might be used during aneurysm surveillance are TAV and rILT. Biomechanical parameters (PWS, RRED) as valuable predictors should be assessed in prospective clinical trials. Similar studies on AAA smaller than 55 mm in diameter, even difficult to organize, would be of even greater clinical value. 2023 Koncar, Nikolic, Milosevic, Bogavac-Stanojevic, Ilic, Dragas, Sladojevic, Markovic, Vujcic, Filipovic and Davidovic.

[No abstract available]

The aim of this study was to demonstrate how fluid dynamic parameters are affected by aortic geometry and flow condition in two cases. Case A included blood flow analysis in aortic system with abdominal aortic aneurysm and left common iliac aneurysm before stent graft placement, while in case B was included stent graft geometry, at the site of the aneurysms. An individual patient-specific geometry and a 3D finite element meshes were reconstructed, based on Computed tomography (CT) scan images. The analysis was performed using the possibilities of computational fluid dynamics. It uses numeric methods and algorithms for the simulation of blood flow by solving the Navier-Stokes equations on computational meshes. The computational simulations of cardiac cycles were performed for average blood properties and blood flow rate. The velocity field, pressure and shear stress, as main fluid dynamics parameters, were visualized and compared for cases A and B. © 2018 S. Djorovic et al.

The aim of this study was to demonstrate how fluid dynamic parameters are affected by aortic geometry and flow condition in two cases. Case A included blood flow analysis in aortic system with abdominal aortic aneurysm and left common iliac aneurysm before stent graft placement, while in case B was included stent graft geometry, at the site of the aneurysms. An individual patient-specific geometry and a 3D finite element meshes were reconstructed, based on Computed tomography (CT) scan images. The analysis was performed using the possibilities of computational fluid dynamics. It uses numeric methods and algorithms for the simulation of blood flow by solving the Navier-Stokes equations on computational meshes. The computational simulations of cardiac cycles were performed for average blood properties and blood flow rate. The velocity field, pressure and shear stress, as main fluid dynamics parameters, were visualized and compared for cases A and B. © 2018 S. Djorovic et al.

Spinal cord ischemia remains the most impressive and colliding complication following open surgical and endovascular aortic procedures. Paraparesis and paraplegia are devastating, having a major invalidating impact on the patient's life. Also for the surgeon and the entire team this dramatic adverse event causes a significant concussion. Surgeons faced this problem in practice in the 1950s when this surgery started being applied. Even A. Carrel in 1910 said, "The main danger of the aortic operation does not come from the heart or from the aorta itself, but from the central nervous system". As the number of these surgeries grew, some were followed by the spinal cord ischemia. Now, in 21st century, problem of spinal cord ischemia still exists. By understanding the reasons of its development we shall be able to find more useful methods for prevention as well as for the treatment. The aim of this article was to search what is behind this dreadful complication, explaining different mechanisms which take part in its development during endovascular and open surgical treatment.

Background: Aneurysms of the extra cranial internal carotid artery (ICA) are rare and caused by infection, arteriosclerosis, fibro muscular dysplasia, neurofibromatosis, Behcet disease, Ehlers-Danlos syndrome, radiotherapy, iatrogenic injury or trauma. Increasing number of high-risk patients and more accurate diagnosing of unapproachable lesions make the consideration of endovascular treatment more acceptable. Methods: We are reporting a case of a 36-year-old male with bilateral aneurysms of ICA and a history of several transitory ischemic attacks. Bilateral successive implantation of a 19mm long covered stent (Jostent) was performed, with a delay of one month between the two procedures. After exclusion of the right ICA with covered stent, patient developed transitory ischemic attack and control multi detector computed tomography revealed occlusion of the left ICA. Results: Further recovery of the patient was uneventful and a control examination after 2 years show patent right ICA, occluded left ICA with no clinical consequences. Conclusions: Patients with recurrent symptoms associated with extra cranial aneurysm need prompt treatment. Surgical resection with various reconstruction techniques is established method. Endovascular exclusion by covered stent in surgically unapproachable aneurysms is feasible; however, there is still need for more technical improvement and experience before it becomes preferable treatment option. © 2012 Springer-Verlag.

The role of intraluminal thrombus (ILT) has special attention in these studies. One of the papers showed that asymmetrical intraluminal thrombus deposition (ATDI) has an important role in growth of the AAA. The aim of our study was to assess the asymmetrical thrombus deposition index in ruptured and symptomatic aneurysms. We collected data for 33 aneurysms, 21 (63.63%) asymptomatic and 12 (33.37%) ruptured or symptomatic. Asymmetrical thrombus deposition index (ATDI) was measured by Onis DICOM viewer software. Also, lumen's geometrical centre (LGC) was defined and ATDI was considered positive when the LGC was laid on the posterior section of the sac (meaning dominant anterior ILT distribution) and negative when it was laid on the anterior section (meaning dominant posterior ILT distribution). Maximum aneurysm diameter was 63.4mm in average (50-100mm, SD=12.89); 59.8mm in asymptomatic and 71.16mm in symptomatic or ruptured aneurysm (p=0.012). The absolute value of asymmetric thrombus deposition index was significantly higher in symptomatic/ruptured compared to asymptomatic aneurysm, 0.54 and 0.33, respectively (p=0.041), while there was no difference in frequency of positive or negative thrombus deposition (p=0.261). There was no significant correlation between maximal aneurysm size and absolute value of ATDI (p=0.505). Values of thrombus deposition index are correlating with the development of symptomatology or rupture of the AAA. This variable should be included in much wider mathematical rupture prediction model in order to have more accurate rupture risk assessment. © 2015 IEEE.

The role of intraluminal thrombus (ILT) has special attention in these studies. One of the papers showed that asymmetrical intraluminal thrombus deposition (ATDI) has an important role in growth of the AAA. The aim of our study was to assess the asymmetrical thrombus deposition index in ruptured and symptomatic aneurysms. We collected data for 33 aneurysms, 21 (63.63%) asymptomatic and 12 (33.37%) ruptured or symptomatic. Asymmetrical thrombus deposition index (ATDI) was measured by Onis DICOM viewer software. Also, lumen's geometrical centre (LGC) was defined and ATDI was considered positive when the LGC was laid on the posterior section of the sac (meaning dominant anterior ILT distribution) and negative when it was laid on the anterior section (meaning dominant posterior ILT distribution). Maximum aneurysm diameter was 63.4mm in average (50-100mm, SD=12.89); 59.8mm in asymptomatic and 71.16mm in symptomatic or ruptured aneurysm (p=0.012). The absolute value of asymmetric thrombus deposition index was significantly higher in symptomatic/ruptured compared to asymptomatic aneurysm, 0.54 and 0.33, respectively (p=0.041), while there was no difference in frequency of positive or negative thrombus deposition (p=0.261). There was no significant correlation between maximal aneurysm size and absolute value of ATDI (p=0.505). Values of thrombus deposition index are correlating with the development of symptomatology or rupture of the AAA. This variable should be included in much wider mathematical rupture prediction model in order to have more accurate rupture risk assessment. © 2015 IEEE.

In this paper, we present a case of kidney injury as a complication of renal artery angioplasty in a 54-year-old female patient that suffered from resistant renovascular hypertension. This case emphasises the unpredictable nature of endovascular procedures, the need for careful post-procedure evaluation and the role of 'old fashioned' surgical techniques in resolving complications of endovascular procedures.; Приводится клинический случай диагностики и лечения повреждения почки как осложнения после ангиопластики почечной артерии у 54-летней пациентки с резистентной вазоренальной гипертензией. Подчеркнута потенциальная непредсказуемость результата эндоваскулярных вмешательств, необходимость тщательного послеоперационного наблюдения и роль 'устаревших' хирургических методов (нефрэктомия) в устранении некоторых осложнений, возникающих при эндоваскулярных вмешательствах.

[No abstract available]

Objective The objective was to quantify aorto-iliac morphology differences between AAA patients of Caucasian and Asian origin. Additionally, the impact of patient demographic characteristics was assessed, which could influence the morphological differences. Methods This international multicentre study included two tertiary referral institutions from Europe and one from China. CT scans with 3D reconstruction of 296 patients with infrarenal AAA >5 cm were analysed. Eighteen measurements were recorded from each CT scan and compared between Caucasian and Asian patients. Results Caucasian patients had longer common iliac arteries (right: 65.0 vs. 33.1 mm, p < .001 left: 65.0 vs. 35.2 mm, p < .001), longer aneurysm neck (33.0 vs. 28.4 mm, p < .001), greater aneurysm to aortic axis angle (153.0° vs. 142.2°, p < .001), and longer combined aorto-iliac length (195.7 vs. 189.2 mm, p < .001). However, Asian patients had a longer infrarenal abdominal aorta (152.0 vs. 130.0 mm, p < .001), longer AAA (126.2 vs. 93.0 mm), and greater linear distance from renal artery to aorto-iliac bifurcation (143.6 vs. 116.0 mm, p < .001). Caucasian patients had a larger inner common iliac artery diameter (right: 16.0 vs. 14.9 mm, p < .001, left: 16.0 vs. 15.2 mm, p < .001), larger inner exernal iliac artery diameter (right: 9.0 vs. 7.5 mm, p < .001 left: 9.0 vs. 7.7 mm, p < .001), and larger inner common femoral artery diameter (right: 10.0 vs. 5.9 mm, p < .001 left: 10.0 vs. 6.1 mm, p < .001). No difference was observed in AAA transverse diameter (62.0 vs. 63.1 mm, p = .492). Conclusion The results showed that aorto-iliac anatomy in Caucasians differs significantly from Asians, particularly in the length of the common iliac arteries and infrarenal abdominal aorta, and in the transverse diameter of the common, external iliac, and common femoral arteries. Therefore, the exact criteria for stent graft design are dependent on the racial origin of the patient. © 2015 European Society for Vascular Surgery

[No abstract available]

This article discusses the etiology of spinal cord ischemia (SCI) mechanisms that may lead to paraplegia during open and endovascular repair from an anatomical and physiological perspective as well as the role of various protective measures used in prevention of this dreadful complication of aortic surgery. There are many adjuncts that must be considered to reduce the risk of spinal cord injury, such as revascularisation of intercostal arteries, maintenance of high mean blood pressure, spinal cord drainage and a few new promising models like NIRS and MISACE which usefulness is yet to be determined. These measures and techniques as well as possible etiology mechanisms of SCI are discussed, highlighting the evidence available for each method, the practical ways in which they may be used, giving some new theories and explanations.