MCBÜ Açıkerişim Sistemi :: Browsing by Author "Yildirim, F"

Browsing by Author "Yildirim, F"

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Systemic inflammatory response during cardiopulmonary bypass: Axial flow versus radial flow oxygenators
Yildirim, F; Senarslan, DA; Yersel, S; Bayram, B; Taneli, F; Tetik, O
Background: The objective of this study was to investigate the inflammatory effects of different oxygenator flow pattern types in patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass. Methods: We designed this randomized, single-blind, prospective study of patients with coronary artery disease. We compared the systemic inflammatory effects of oxygenators with two types of flow: axial flow and radial flow. Therefore, we divided the patients into two groups: 24 patients in the axial group and 28 patients in the radial group. IL-1, IL-6, IL-10, and TNF-alpha were examined for cytokine activation leading to a systemic inflammatory reaction. The samples were collected at three different time intervals: T1, T2, and T3 (T1 was taken before cardiopulmonary bypass, T2 just 1 h after CPB onset, and T3 was taken 24 h after the surgery). Results: There were no significant differences in demographic characteristics between the two groups. We observed that there were notably lower levels of humoral inflammatory response parameters (IL-1, IL-6, and TNF-alpha) in the radial flow oxygenator group than in the axial flow group at the specific sampling times. For IL-10, there was no significant difference for any time period. Conclusion: It might be advantageous to use a radial-flow-patterned oxygenator to limit the inflammatory response triggered by the oxygenators in cardiopulmonary bypass.
Production and Characterization of Composite Filaments for 3D Printing
Çanti, E; Aydin, M; Yildirim, F
In this study, various nano and micro particles with different properties, including density, surface area, purity and particle morphology were used as reinforcement particles for the production of polymer composite filaments to be used for 3D printing. Acrylonitrile Butadiene Styrene (ABS) was matrix material and Multi wall carbon nanotubes (MWCNTs), SiO2, ZrB2, and, Al particles were reinforcements. Production of the composite filaments was carried out by using a twin screw extruder. Produced composite filaments were characterized via Differential Scanning Calorimeter (DSC), Scanning Electron Microscope (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), tensile test and surface roughness tests. Results showed that addition of micro/nano particles into ABS matrix improved the Ultimate Tensile Strength (UTS) of the composites by around 16% compared to non-reinforced one. As a result of reinforcing with micro particles, ZrB2 and Al, the tensile strain of neat-ABS filament increased by 17.8% and 40%, respectively
Urgent Right Coronary Artery Bypass Surgery Due to Stent Distortion by a Stitched Guidewire.
Senarslan, DA; Yildirim, F; Özbakkaloglu, A; Kurdal, AT; Bayram, B; Damar, A; Iskesen, I; Cerrahoglu, M; Tetik, Ö
Improved mechanical performance of three-dimensional woven glass/epoxy spacer composites with carbon nanotubes
Yildirim, F; Aydin, M; Avci, A
Three-dimensional polymer composites offer various features and design options due to their hollow structure and lightweight. However, to exploit their advantages, it is a must to improve their structural features and mechanical performances including out-plane direction. Although introducing thermoplastic fillers between the plies or multilayered design addresses on this critical issue, the benefits offered by the nanoparticles with superior mechanical properties come a step forward as an another engineering solution. Based on this motivation, the goal of this study is to investigate the impact of multiwalled carbon nanotubes on the mechanical and thermomechanical performances of three-dimensional woven glass/epoxy spacer composites. Therefore, multiwalled carbon nanotubes at various content were introduced into epoxy matrix, and the multiwalled carbon nanotubes-epoxy mixture was infused to three-dimensional woven fabric with the vacuum-assisted resin transfer method. The obtained results indicated that the three-point bending strength and modulus were enhanced up to 25 and 80% for warp direction and enhanced up to 44 and 85% for weft direction with carbon nanotube addition, respectively. Tensile strength developed in the warp direction by 7%, while the strength value in the weft direction did not change. The tensile strain values for warp and weft directions enhanced up to 19 and 12% with carbon nanotube addition, respectively. In addition, thermomechanical analysis has revealed that the glass transition temperature and storage modulus were also improved. Particle dispersion detection with color measurement and scanning electron microscopy analyses revealed the effectiveness of the ultrasonic mixing on the dispersion of carbon nanotubes in the epoxy matrix. The consequences of carbon nanotube addition on microscale morphology were discussed based on the fracture morphologies to nanoscale and microscale toughening mechanisms in the existence of carbon nanotube reinforcement.
Ultrasound-guided catheter-directed foam sclerotherapy for great saphenous vein
Kurdal, AT; Yildirim, F; Ozbakkaloglu, A; Iskesen, I; Tetik, O
Aim. The problem of varicose veins in the lower leg is a common disease and associated with long-term morbidity. It has usually been treated using high ligation with stripping and endovenous ablation surgery of the great saphenous vein. The aim of this paper is to report our own series of patients treated by ultrasound guided catheter directed foam sclerotherapy for the chemical ablation of great saphenous vein. Methods. The study involved 108 legs with symptomatic varicose veins (C2-4) secondary to great saphenous vein insufficiency. The great saphenous vein was accessed at knee level. With the method of Tessari sclerosant foam was made (2 mL 3% polidocanol and 8 mL air) and delivered along the great saphenous vein while the catheter was withdrawn. At two and fifty two weeks after treatment the patients were evaluated. Results. Catheter-directed foam sclerotheraphy was successfully performed in all of the patients. Venous Clinic Severity Score was reduced significantly (P<0.05). Eighty nine percent of the GSV were completely occluded, 4% were partly occluded and 7% were recanalized. No serious side-effects occurred. Conclusion. Catheter-directed foam sclerotheraphy is a safe, simple and minimally invasive procedure. Patient satisfaction was good and the occlusion rate is promising after a single treatment.
Opening the cardiac chambers does not make any difference in P300 measurement
Iskesen, I; Yilmaz, H; Yildirim, F; Selcuki, D
Objective. Cognitive brain dysfunction after open heart surgery is a serious complication caused by cardiopulmonary bypass (CPB). The presence of gaseous and/or particulate emboli in the CPB circuit and cerebral hypoperfusion may be the causes of neurologic problems after cardiac operations. Methods. In this prospective study we examined 42 consecutive cardiac surgery patients ( 24 mitral valve replacement [MVR] and 18 coronary artery bypass grafting [CABG] patients). In addition to determination of clinical measurements, cognitive brain function was measured objectively by P300 auditory-evoked potentials before operation, at day 7, and at 4-month follow-up. Electroencephalographic evaluations were also performed. Results. In preoperative measures there was no difference between the groups ( peak latencies in the MVR group were 324 +/- 8 milliseconds; CABG group, 318 +/- 6 milliseconds; P >.05). At day 7, cognitive P300 auditory-evoked potentials were significantly impaired ( prolonged) in both groups compared to preoperative values ( MVR group, 347 +/- 7 milliseconds; CABG group, 342 +/- 7 milliseconds; P <.05). P300 measurements almost returned to normal at 4-month follow-up ( MVR group, 331 +/- 6 milliseconds; CABG group, 319 +/- 8 milliseconds; P >.05 compared to preoperative values). One week and 4 months after surgery no difference between the 2 groups could be found ( P >.05). Conclusion. Postoperative patients had prolonged P300 values according to the preoperative measurements and we have not found any difference between the groups whether cardiac chambers were opened or not.
N-terminal ProBNP levels can predict cardiac failure after cardiac surgery
Cerrahoglu, M; Iskesen, I; Tekin, C; Onur, E; Yildirim, F; Sirin, BH
Background The aim of this study was to evaluate, the relationship between the preoperative N-terminal proB-type natriuretic peptide (NT-proBNP) level and the need for the inotropic support in the early postoperative period of patients undergoing coronary artery bypass graft surgery. Methods and Results The patients were divided into 2 groups: NT-proBNP level < 220pg/ml (group A, n=26) or > 220 pg/ml (group B, n=26). The normal value for NT-proBNP level was accepted as < 220 pg/ml. The cardiac output was measured on arrival in intensive care and at the 16(th) hour. The groups were compared with respect to early postoperative hemodynamic measurements, urinary output, use of inotropic agents and requirement for additional cardiac-assist devices. Left ventricular ejection fraction, cardiac output and cardiac index were lower in group B and inotropic agents were used for a longer period of time and at higher doses in this group (p < 0.05). Conclusion Measurement of the NT-proBNP level in the period before cardiac surgery can indicate the postoperative prognosis of the patient and may be a predictor of the need for postoperative inotropic treatment.
The effects of perioperative goal-directed therapy on acute kidney injury after cardiac surgery in the early period
Özdemir, I; Ozturk, T; Amanvermez, D; Yildirim, F; Sengel, A; Özdemir, IH
Background: This study aims to investigate the effects of goal directed fluid therapy on the development of acute kidney injury in the perioperative period in patients undergoing cardiopulmonary bypass.Methods: Between November 2019 and May 2021, a total of 60 patients (46 males, 14 females; mean age: 62.5 +/- 9.6 years; range, 44 to 76 years) who were scheduled for elective coronary artery bypass grafting or valve surgery under cardiopulmonary bypass were included in the study. The patients were divided into two groups as the study group (Group S, n=30) and control group (Group C, n=30). The patients in Group C were treated with standard therapy, while the patients in Group S were treated with goal-directed fluid therapy. The Kidney Disease: Improving Global Outcomes (KDIGO) classification and renal biomarkers were used for the evaluation of acute kidney injury.Results: Acute kidney injury rates were similar in both groups (30%). Postoperative fluid requirement, intra-, and postoperative erythrocyte suspension requirements were significantly lower in Group S than Group C (p=0.002, p=0.02, and p=0.002, respectively). Cystatin-C was lower in Group S (p<0.002). The kidney injury molecule-1, glomerular filtration rate, and creatinine levels were similar in both groups. The length of hospital stay was longer in Group C than Group S (p<0.001).Conclusion: Although goal-directed fluid therapy does not change the incidence of acute kidney injury in patients undergoing cardiac surgery, it can significantly decrease Cystatin-C levels. Goal-directed fluid therapy can also decrease fluid and erythrocyte requirements with shorter length of hospital stay.
Efficacy and cost-effectiveness of cell saver usage in the repair of thoracic aortic aneurysms and dissections
Senarslan, DA; Yildirim, F; Kurdal, AT; Damar, A; Ozturk, T; Tetik, O
Introduction: A substantial amount of blood loss occurs during the open repair of aortic aneurysms or dissections. The aim of the present study is to determine the efficacy and cost-effectiveness of cell saver devices in blood conservation during the open repair of thoracic aortic pathologies. Methods: The present study prospectively collected the data pertaining to 25 patients who underwent surgical management of thoracic aortic aneurysms or dissections using a cell saver (Group 1, n = 25). The volume and cost of transfusion and postoperative outcomes were compared with the second group of patients who underwent surgery without the use of cell savers in the previous year (Group 2, n = 25); the data pertaining to the same were retrospectively collected from the hospital records. The patient characteristics and categorical variables were compared using the x(2) test and Fisher's exact test. Transfusion volume and costs were compared using the independent samples t-test and Mann-Whitney U test. Results: The patients in both the groups displayed similar characteristics and risk factors. The total volume of allogenic red blood cell (p < 0.001) and total blood product (p = 0.01) transfusions were significantly lower in Group 1. The cost of red blood cell (p < 0.001) and total transfusions (p = 0.03) were lower in Group 1. The two groups displayed similar in-hospital morbidity and mortality rates. Conclusions: There was a significant association between the use of cell savers and the decreased need for red blood cell and total blood product transfusions. Considering the cost of the cell saver set, transfusion costs in the two groups were comparable.
Is Attenuation of Oxidative Stress Helpful to Understand the Mechanism of Remote Ischemic Preconditioning in Cardiac Surgery?
Yildirim, F; Iskesen, I; Kurdal, AT; Ozturk, T; Taneli, F; Gozukara, C; Ozbakkaloglu, A
Objectives: The aim of this study was to determine the effect of remote ischemic preconditioning (RIPC) on markers of cardiac ischemia and response to oxidative stress in patients undergoing coronary artery bypass grafting (CABG) surgery. Design: A prospective, randomized, and blinded study. Setting: A single-center university hospital. Participants: This study included patients who underwent isolated CABG surgery with cardiopulmonary bypass who were selected carefully to prevent confounding with factors known to affect markers of ischemia-reperfusion and response to oxidative stress. Interventions: The authors randomly assigned patients to RIPC to the left lower extremity using a blood pressure cuff (study group) or a cuff that was applied but not inflated or deflated (control group). Measurements and Main Results: At 6 hours after CABG surgery, high-sensitivity cardiac troponin T levels were significantly lower in the study group than in the control group. Levels of superoxide dismutase, an antioxidant enzyme, were significantly greater 15 minutes after release of the cross-clamp in the study group, whereas malondialdehyde levels were lower (not significantly) at 1 and 15 minutes after release of the cross-clamp. Hemodynamic parameters were not significantly different at any time point during the study. Conclusions: The authors' method of RIPC before CABG surgery resulted in less myocardial ischemia, as indicated by lower troponin levels. Changes in levels of endogenous antioxidant enzymes supported the hypothesis that this protection from ischemia-reperfusion injury was related to scavenging of free oxygen radicals. Future studies might include a more heterogeneous population and medications that lower the body's response to oxidative stress. (C) 2016 Elsevier Inc. All rights reserved.
Results of endovascular treatments of Trans-Atlantic Inter-Society Consensus C or D aortoiliac occlusive disease involving the aortic bifurcation
Senarslan, DA; Yildirim, F; Bayram, B; Kurdal, AT; Tetik, O
Objectives:The current study aims to report midterm results of patients treated with endovascular intervention, kissing stent, or covered endovascular reconstruction of the aortic bifurcation, for Trans-Atlantic Inter-Society Consensus C or D aortoiliac occlusive disease involving the aortic bifurcation.Methods:Eighteen patients who have intermittent claudication or chronic limb threatening ischemia with Trans-Atlantic Inter-Society Consensus C or D aortoiliac occlusive disease involving the aortic bifurcation enrolled to the study between January 2018 and January 2021. Kissing stents, Advanta V12 (Atrium, Getinge Group), were used in 13 patients, and the covered endovascular reconstruction of the aortic bifurcation technique was used in 4 patients to reconstruct the aortic bifurcation. The patients were followed for a median of 49 months (min. 2, max.58 months). Patency rates, mortality, morbidities, and reinterventions were recorded.Results:The mean age of the patients was 60.4 & PLUSMN; 10 years. Technical success was achieved in 94.4% of the patients, but one patient had to convert to open surgery. Primary patency rate of the remaining patients was 85.6% at 58 months. Target lesion revascularization rate was 11.7%. One patient had successful reintervention for in stent restenosis, and secondary patency rate was 93.3% at 58 months. Limb salvage rate was 84.6% during the follow-up. Two patients had myocardial infarction (11.1%) and one mortality (5.6%) occurred because of cerebrovascular event in the follow-up.Conclusions:Endovascular techniques can be used safely for reconstruction of the aortic bifurcation in Trans-Atlantic Inter-Society Consensus C or D aortoiliac occlusive disease in selected patients who have high risk for open surgery. Covered endovascular reconstruction of the aortic bifurcation is the only technique that showed patency rates approaching open surgery in treatment of aortoiliac occlusive disease involving the aortic bifurcation to date. Although promising patency results were achieved with kissing-covered stents, long-term patency rates were still lower than those achieved with open surgery. Further randomized controlled studies comparing the long-term results of these techniques are needed.
Management of a patient with giant aneurysms in the popliteal and coronary arteries
Yildirim, F; Senarslan, DA; Ozturk, T; Tetik, O
Coexistence of multiple peripheric arterial and coronary artery aneurysms of different sizes is extremely rare in young adults. We present a case of rare giant coronary aneurysm and concurrent giant left popliteal aneurysm treated with classical open repair.
Bentall Operation in a Patient With Severe Hemophilia A and Marfan Syndrome by Use of a Biologic Composite Graft
Yildirim, F; Ozbakkaloglu, A; Ozturk, T; Tetik, O
We describe a patient with severe hemophilia A and Marfan syndrome who underwent an elective Bentall operation. Because of the severe hemophilia, anticoagulation could not be given postoperatively; thus, a biologic Valsalva conduit graft was used. During the procedure, factor VIII was given as a bolus dose just before incision, then by continous infusion intra-operatively to maintain the factor VIII activity level between 200% and 300%. Minimal postoperative bleeding occurred. The infusion was continued postoperatively at a lower dose until all chest tubes, pacing wires, and invasive catheters were removed. The patient was discharged on postoperative day 7 without adverse events. (C) 2016 by The Society of Thoracic Surgeons
Three Cases of Large-Diameter True Brachial and Axillary Artery Aneurysm and a Review of the Literature
Senarslan, DA; Yildirim, F; Tetik, O
Aneurysms of the upper extremity mostly originate from trauma, mycotic lesions, thoracic outlet syndrome, previous arteriovenous fistulae, and atherosclerosis. True aneurysms of the brachial and axillary artery are encountered rarely. They can be diagnosed by simple physical examination as a pulsatile mass. However, most of these aneurysms remain asymptomatic until a complication occurs. The primary complication seen with the axillary or brachial artery is embolization. We report 3 large-diameter true brachial artery aneurysms extending to the axillary zone. One of the patients had distal digital emboli causing gangrenous lesions at the finger tips and the other 2 patients had pain and ischemic symptoms in the forearm. All underwent surgical repair. After excision of the aneurysmal segment, arterial continuity was ensured by interposition of a reversed saphenous vein in 2 patients and with a biological vascular graft in 1 patient. Although endovascular techniques are improving, most true brachial artery aneurysms are not anatomically suitable for interventional procedures. Open surgery still preserves its value.
Pleura preservation during coronary operation does not have any beneficial effect on respiratory functions
Iskesen, I; Kurdal, AT; Yildirim, F; Cerrahoglu, M; Sirin, H
Aim. According to some reports the destruction the integrity of the pleura during acute myocardial infarction (AMI) harvesting during coronary surgery may also impair respiratory function in the postoperative period. The purpose of this study was to evaluate the influence of preserved integrity of pleura on respiratory function in patients undergoing coronary artery bypass grafting (CABG). Methods. One hundred and forty-three patients who had on-pump-CABG operation with pedunculated LIMA graft were divided to 2 groups. The first group is the study group that pleura opened (group OP; N=69), and the other group is that their pleura protected (group C, N=74). All patients were evaluated with using respiratory function test parameters (functional vital capacity [FVC], force expiratory volume %-at the 1(st) second [FEV1%] in the preoperative period and on the 7(th) postoperative day). Respiratory problems, blood drainage amounts and used blood products in the postoperative period were measured. Results. Preoperative FVC values were not different between the two groups (3.08+/-0.5 in group C and 3.37+/-0.7 L in OP group) (P>0.05). On the VII postoperative day this parameter did not show any significant difference between the groups (2.80+/-0.6 in group C and 2.75+/-0.5 liter in OP group) (P>0.05). Preoperative FEV1% values did not show any difference (77.6+/-4.6% and 76.0+/-2.7% in OP and C groups respectively. There was no significant difference between the postoperative FEV1% values (71.8+/-5.1% and 73.4+/-6.3% respectively) (P>0.05). Patients with protected pleura had significantly lower blood drainage and whole blood unit transfusion (P<0.05). Conclusion. Preservation of the pleural integrity during LIMA harvesting significantly reduces postoperative bleeding but not affects pulmonary functions.
Impact response of nanoparticle reinforced 3D woven spacer/epoxy composites at cryogenic temperatures
Yildirim, F; Tatar, AC; Eskizeybek, V; Avci, A; Aydin, M
Fiber-reinforced polymer composites serving in harsh conditions must maintain their performance during their entire service. The cryogenic impact is one of the most unpredictable loading types, leading to catastrophic failures of composite structures. This study aims to examine the low-velocity impact (LVI) performance of 3D woven spacer glass-epoxy composite experimentally under cryogenic temperatures. LVI tests were conducted under various temperatures ranging from room temperature (RT) to -196 degrees C. Experimental results reveal that the 3D composites gradually absorbed higher impact energies with decreasing temperature. Besides, the effect of multi-walled carbon nanotube and SiO2 nanofiller reinforcements of the matrix on the impact performance and the damage characteristics were further assessed. Nanofiller modification enhanced the impact resistance up to 30%, especially at RT. However, the nanofiller efficiency declined with decreasing temperature. The apparent damages were visually examined by scanning electron microscopy to address the damage formation. Significant outcomes have been achieved with the nanofiller modification regarding the new usage areas of 3D woven composites.

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