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Öğe Evaluation of clinical results of esmarch bandage application in giant saphenous vein closure during endovenous glue ablation(Clinics Cardive Publ Pty Ltd, 2024) Karahan, Oguz; Akkaya, Ozgur; Aydogan, EyupBackground: In recent years, the endovenous technique has been presented as a good alternative to surgery in the treatment of patients with lower extremity varicose veins. However, its effectiveness in very advanced saphenous vein diameters is controversial. In this study, we investigated the results of an endovenous glue ablation closure system applied with an esmarch bandage in saphenous veins with very large diameters. Methods: Eighty-nine patients who were operated on for varicose veins were divided into three groups according to their saphenous vein diameters: less than 10 mm (group 1), between 10 and 15 mm (group 2), and larger than 15 mm (group 3). Endovenous closure was performed with n-butyl cyanoacrylate in all patients. An esmarch bandage was applied during the procedure to all patients, except for the group with a diameter of less than 10 mm. This group underwent the standard procedure. All patients were followed up for six months after the procedure and postoperative symptoms, complications and closure rates were recorded. Results: There was complete closure of all veins in the first month postoperatively. While no thrombophlebitis was observed in group 3, thrombophlebitis was detected in two patients in groups 1 and 2. In the third month, minimal saphenofemoral reflux was observed in two (4.2%) patients in group 1 and in one (4.3%) in group 2. In the sixth month, minimal saphenofemoral reflux was detected in three (6.3%) patients in group 1 and in one (4.3%) in group 2. No residual leakage was observed in group 3 (p = 0.001). In all groups, the severity score regressed significantly in the postoperative sixth month. However, the most significant symptomatic regression was observed in group 3, which had the largest saphenous diameters and we used an esmarch bandage during closure (p = 0.000).Conclusion: Our findings support the idea that the application of an esmarch bandage during endovenous closure improves clinical outcomes, especially in saphenous veins with larger diameters.Öğe Investigation of Rupture Risk of Thoracic Aortic Aneurysms via Fluid-Structure Interaction and Artificial Intelligence Method(Springer Heidelberg, 2024) Koru, Murat; Canbolat, Gokhan; Daricik, Fatih; Karahan, Oguz; Etli, Mustafa; Korkmaz, ErgunPatient-specific studies on vascular flows have significantly increased for hemodynamics due to the need for different observation techniques in clinical practice. In this study, we investigate aortic aneurysms in terms of deformation, stress, and rupture risk. The effect of Ascending Aortic Diameter (AAD) was investigated in different aortic arches (19.81 mm, 42.94 mm, and 48.01 mm) via Computational Fluid Dynamics (CFD), Two-way coupling Fluid-Structure Interactions (FSI) and deep learning. The non-newtonian Carreau viscosity model was utilized with patient-specific velocity waveform. Deformations, Wall Shear Stresses (WSSs), von Mises stress, and rupture risk were presented by safety factors. Results show that the WSS distribution is distinctly higher in rigid cases than the elastic cases. Although WSS values rise with the increase in AAD, aneurysm regions indicate low WSS values in both rigid and elastic artery solutions. For the given AADs, the deformations are 2.75 mm, 6. 82 mm, and 8.48 mm and Equivalent von Mises stresses are 0.16 MPa, 0.46 MPa, and 0.53 MPa. When the rupture risk was evaluated for the arteries, the results showed that the aneurysm with AAD of 48.01 mm poses a risk up to three times more than AAD of 19.81 mm. In addition, an Artificial neural network (ANN) method was developed to predict the rupture risk with a 98.6% accurate prediction by numerical data. As a result, FSI could indicate more accurately the level of rupture risk than the rigid artery assumptions to guide the clinical assessments and deep learning methods could decrease the computational costs according to CFD and FSI.Öğe Investigation of the Endothelial Response of the Super Elastic Braided Stent: An Experimental Evaluation(2020) Karahan, Oguz; Ocal, Naci; Anteplıoglu, Tugce; Hafız, Erhan; Khalıl, EmcedAim: This study aimed to experimentally investigate the vascular biocompatibility of the new super elastic braided stents and ultrasonographically follow up the mid-term outcomes on the blood flow of stent-implanted vessels. Method: After designation of the study steps, stents were implanted into the iliac arteries of two ewes. The preoperative and postoperative blood flow and local findings were noted. The ewes were inspected periodically for abnormal body changes, and the stent-implanted vessels were checked with Doppler ultrasonography. The subjects were sacrificed at six months, and the iliac arteries were examined histopathologically. Results: During follow up an occlusive pattern was not observed in the stentimplanted vessels. The histopathological analysis revealed that both two stent area had no significant neointimal hyperplasia, despite sufficient re-endothelisation at the stent surface. Occlusive or stenotic patterns were not detected in both macroscopic and microscopic findings. Conclusion: According to the mid-term findings, our results show that the new super elastic bare stents have good vascular biocompatibility with high patency rates.Öğe INVESTIGATION OF VASCULAR FLOW IN A THORACIC AORTA IN TERMS OF FLOW MODELS AND BLOOD RHEOLOGY VIA COMPUTATIONAL FLUID DYNAMICS (CFD)(World Scientific Publ Co Pte Ltd, 2024) Canbolat, Gokhan; Etli, Mustafa; Karahan, Oguz; Koru, Murat; Korkmaz, ErgunThe studies on vascular flows have increased in the last decade. In this work; we have focused on the effects of flow model and blood rheology on hemodynamics for a real-subject scan using Computed Tomography Angiography (CTA) during numerical solutions. Various vascular flow studies using Newtonian or non-Newtonian blood models were presented in the literature with laminar or turbulent flow assumptions. In this study; six different turbulent models (Realizable k-epsilon, Standard k-epsilon, SST k-omega, Standard k-omega, Transition k-kl-omega, Transition SST) were compared to laminar flow to show whether turbulent flow solution is necessary. Blood rheology was investigated by using five different non-Newtonian models (Carreau, Herschel-Bulkley, Carreau-Yasuda, Casson, Power-Law) in addition to Newtonian model to indicate whether non-Newtonian blood assumptions is necessary. The In vivo boundary conditions were utilized by the UDF code which defines the real-patient cardiac cycle obtained by Echocardiography (ECHO) to present hemodynamics in the study. The results show that laminar flow well matched with the four turbulent models and two models shows by 4.8% and 19.5% differences in Wall Shear Stress (WSS) according to laminar flow. When the blood rheology was investigated, results revealed significant differences in WSS by 25.7%, 8.7%, 22.4%, 12.3%, and 32.5% for the non-Newtonian models in the given order, respectively, compared to Newtonian assumption. It concluded that laminar flow solution could be effective instead of solving turbulent flows in terms of computational cost, however, non-Newtonian blood effects could be considered to determine critical hemodynamics levels in a normal aortic arc.Öğe Predicting Postoperative Atrial Fibrillation Using HARMS2-AF Score(Kare Publ, 2024) Oncel, Can Ramazan; Koseoglu, Cemal; Dagasan, Goksel; Coner, Ali; Ayhan, Selcuk; Akkaya, Ozgur; Karahan, OguzBackground Postoperative atrial fibrillation (POAF) remains a common complication after cardiac surgery. The ability to accurately identify patients at risk through previous risk scores is limited. This study aimed to evaluate the new HARMS(2)-AF risk score to predict POAF after coronary artery bypass grafting (CABG) surgery. Methods In this retrospective cohort study, we included 265 patients undergoing CABG surgery from 2022-2023. Data were obtained from the medical files of the patients and hospital records. Each patient was assigned a HARMS(2)-AF risk score. A univariate and multivariate regression analyses were done to analyze independent predictors of POAF. Results Of 265 patients, 49 had postoperative atrial fibrillation. HARMS(2)-AF score was significantly higher in patients with POAF. Age, sleep apnea, left atrial diameter (LAd), and HARMS(2)-AF score were independently associated with POAF. A HARMS(2)-AF score >= 4.5 predicted POAF with 91% sensitivity and 64% specificity (AUC = 0.787, 95% CI = 0.731-0.842, P < .001). Conclusion The HARMS(2)-AF score is a strong predictor of atrial fibrillation (AF) development after isolated CABG surgery. It can be used as a novel stratification tool to estimate AF after cardiac surgery.Öğe Scientificity and H-Index(2020) Karahan, Oguz; Aslan, AhmetScientificity is a comprehensive expression that identifies the scientific contribution of an academician or a scientist to the literature. It is established on the basis of certain determinants, such as the h-index, which is one of the indicators used to evaluate the degree of scientificity in a contribution. This editorial explains the h-index and its necessity.Öğe Structures of Cytoskeleton and Disease Interactions(2019) Melekoglu, Abdullah; Karahan, OguzResearchers reported different basics for different kind of diseases with advancedtechnology. Meanwhile, investigators are focused on to clarify the interactions ofbasic cellular mechanisms recently. Therefore, cytoskeletal researches are gain importance due to this tendency. The cytoskeletal structures are responsible for interconnects between cell nucleus, cytoplasm and also extracellular matrix, whereby itcreate a communication link between cellular molecules and signalization transport.The cytoskeleton is constructed from three kinds of protein filaments as: actin filaments, intermediate filaments, and microtubules. The nature of these structures isbriefly outlined and the literature review that is reporting relationship between cytoskeleton components and common disorders is presented in this paper.Öğe The effects on clinical outcomes of administering medications together or separately in prolonged dual antiplatelet therapy after peripheral revascularisation(Clinics Cardive Publ Pty Ltd, 2024) Akkaya, Ozgur; Karahan, OguzBackground: In the current guidelines, dual antiplatelet therapy [acetylsalicylic acid (ASA) + clopidogrel] is recommended for at least three months after peripheral iliac stenting. In this study, we investigated the effect on clinical outcomes of adding ASA in different doses and at different times after Methods: Seventy-one patients were administered dual antiplatelet therapy after successful iliac stenting. Group 1, consisting of 40 patients, was given 75 mg of clopidogrel plus 75 mg of ASA in a single dose in the morning. In group 2, separate doses of 75 mg of clopidogrel (in the morning) and 81 mg of 1 x 1 ASA (in the evening) were started in 31 patients after the procedure were recorded. resulting in reduced haemoglobin levels (p = 0.038). dose of ASA.Öğe The Oxidative and Anti-Angiogenic Effects of Acrylamide in Chorioallantoic Membrane Model(2023) Sozen, Mehmet Enes; Akkaya, Özgür; Savas, Hasan Basri; Karahan, OguzObjective: Acrylamide (ACR) is formed spontaneously during the preparation of carbohydrate-containing foods by exposure to high heat and can be found in large amounts in processed ready-made foods like potato crisps, biscuits, crackers, and bread. ACR is a toxic substance and increases oxidative stress. The aim of the study is to show the effects of ACR exposure at different doses on angiogenesis and oxidant-antioxidant balance in the chorioallantoic membrane (CAM) model. Methods: Two different concentrations of ACR were prepared (10-3 M and 10-4 M). Pellets were placed on the CAM of the embryos. Liquid samples were taken from fertilized chicken eggs before and after the experiment. Anti-angiogenic effects were evaluated through the window that was opened on the eggshell. Results: The 10-4 M ACR group caused anti-angiogenic effects (average score 0.3) which were higher than the control group, but these changes were not statistically significant. The 10-3 M ACR group caused moderate anti-angiogenic effects (average score 0.6). The 10-6 M Bevacizumab group caused powerful anti-angiogenic effects (average score 1). There is a significant increase in total oxidant capacity (TOC) and oxidative stress index (OSI) values in 10-3 M ACR and 10-4 M ACR groups, compared to the control group. Although there was a numerical increase in TOC and OSI values in 10-3 M ACR group compared to 10-4 M ACR group, this increase was not statistically significant. Conclusion: This study is the first to investigate the anti-angiogenic effects of ACR and is one of the first to investigate oxidative stress in the CAM model. ACR exposure increased oxidative stress in the CAM model and showed a dose-dependent anti-angiogenic effect.
