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Dive into the research topics where Erdem Çankaya is active.

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Featured researches published by Erdem Çankaya.


Transplantation Proceedings | 2013

Does a Predialysis Education Program Increase the Number of Pre-emptive Renal Transplantations?

Erdem Çankaya; R. Cetinkaya; Mustafa Keles; E. Gulcan; Abdullah Uyanik; A. Kisaoglu; B. Ozogul; G. Ozturk; Bulent Aydinli

OBJECTIVES Renal transplantation (RT) is the most appropriate form of treatment for end-stage renal disease (ESRD). Pre-emptive RT decreases the rates of delayed graft function and acute rejection episodes, increasing patient and graft survival, while reducing costs and complications associated with dialysis. In this study, we investigated the relationship between a predialysis education program (PDEP) for patients and their relatives and pre-emptive RT. METHODS We divided 88 live donor kidney transplant recipients into 2 groups: transplantation without education (non-PDEP group; n = 27), and enrollment in an education program before RT (PDEP group n = 61). RESULTS Five patients in the non-PDEP group underwent pre-emptive transplantation, versus 26 of the PDEP group. The rate of pre-emptive transplantations was significantly higher among the educated (42.62%) versus the noneducated group (18.51%; P < .001). CONCLUSION PDEP increased the number of pre-emptive kidney transplantations among ESRD patients.


Renal Failure | 2014

Does decreased mean platelet volume predict inflammation in chronic renal failure, dialysis, and transplanted patients?

Yusuf Bilen; Erdem Çankaya; Mustafa Keles; Erim Gulcan; Abdullah Uyanik; Mehmet Turkeli; Bulent Albayrak; Rahsan Yildirim

Abstract Objectives: Increased platelet activation contributes to cardiovascular mortality in chronic kidney disease patients (CKD). Larger platelets are more active and this increased activity had been suggested as a predictive biomarker for cardiovascular disease. In this study, we aimed to evaluate mean platelet volume (MPV) as an inflammatory marker in a broadened group of CKD patients. Our study is unique in literature as it covers all types of CKD including renal replacement therapies. Materials and methods: 200 patients (50 renal transplanted, 50 hemodialysis, 50 peritoneal dialysis, 50 chronic renal failure stages 3–4) were investigated who were between 18 and 76 years of age. The collected data included demographic properties, platelet count, MPV, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and hemoglobin. All of the patients had at least 12 month of therapy of either renal replacement modality. Results: The mean CRP value was detected statistically significantly higher in hemodialysis (HD) patients compared to the resting three groups of patients (p < 0.01). Mean CRP level was detected significantly higher in the pre-dialysis group compared to transplanted and peritoneal dialysis (PD) patients (p < 0.01). There is no statistically significant difference detected among the mean MPV values of all patient groups (p > 0.05). Conclusions: ESR and CRP were significantly increased in hemodialysis patients compared to the other groups. We did not detect a significant difference among MPV between the groups. ESR was detected lowest in transplanted patients. Transplantation is coming forward as the favorable choice of renal replacement therapy which decreases inflammation.


Transplantation Proceedings | 2015

Comparison of Serum Vitamin D Levels Among Patients With Chronic Kidney Disease, Patients in Dialysis, and Renal Transplant Patients

Erdem Çankaya; Yusuf Bilen; M. Keleş; Abdullah Uyanik; M. Akbaş; A. Güngör; Ş. Arslan; Bulent Aydinli

OBJECTIVE Vitamin D is a hormone with a variety of functions, and its deficiency and insufficiency are commonly seen both in the general population and in patients with chronic renal disease. The aim of this study was to compare vitamin D levels in patients with chronic renal disease who are on hemodialysis, peritoneal dialysis, or no renal replacement therapy and patients who underwent renal transplantation. METHODS A total of 169 patients who had not used vitamin D for ≥ 1 year and who had no diabetes mellitus or proteinuria were included in the study. These included: 40 patients with renal transplantation, 40 patients on hemodialysis, 49 patients on peritoneal dialysis, and 40 patients with chronic renal failure stage 1, 2, 3, or 4. 25-Hydroxy vitamin D levels were evaluated in the sera of the patients. RESULTS 25-Hydroxy vitamin D levels in patients with renal transplantation and in predialysis patients were 12.74 ± 10.24 ng/mL and 11.16 ± 12.25 ng/mL, respectively. The levels were 7.77 ± 6.71 ng/mL and 5.96 ± 4.87 ng/mL in patients on hemodialysis and peritoneal dialysis, respectively. CONCLUSIONS Vitamin D levels are lower in patients on hemodialysis and peritoneal dialysis compared with the patients with renal transplantation for a variety of reasons. In this study, objective results were obtained supporting the administration of vitamin D supplements without glomerular filtration rate measurement in all patient groups with the diagnosis of chronic renal failure in accordance with the guidelines.


Transplantation Proceedings | 2015

Neutrophil-Lymphocyte Ratio Is Significantly Decreased in Preemptive Renal Transplant Patients

Erdem Çankaya; Yusuf Bilen; Mustafa Keles; Abdullah Uyanik; Nurhan Bilen; Bulent Aydinli

AIM Cardiovascular diseases and infections are the leading two causes of morbidity and mortality in end-stage renal disease (ESRD) patients. Kidney transplantation is the preferred method for renal replacement owing to better survival. There are reports of irreversibly damaged immune system in dialysis patients, which did not return to normal even after kidney transplantation. The neutrophil-lymphocyte ratio (NLR) is an easily applicable method for evaluation of inflammation. We hypothesized that preemptive kidney transplantation can improve inflammatory state compared with nonpreemptive recipients. To test our hypothesis, we retrospectively investigated pretransplant and posttransplant NLR and C-reactive protein (CRP) levels of ESRD patients and compared them with values in healthy controls. MATERIALS AND METHODS We retrospectively analyzed NLR, CRP, and other hematologic parameters of ESRD patients who were transplanted between January 2005 and January 2014 on the day of transplantation and at the end of first year. We grouped the patients as preemptive and nonpreemptive ones. We excluded patients with coronary artery disease, obesity, hypotension, hyperthyroidism, uncontrolled diabetes mellitus, hematologic or solid organ cancers, and active documented infection at any evaluation period. RESULTS We included 137 ESRD patient and 34 healthy control individual in our study. Of the 137 ESRD patients, 52 (38%) were transplanted preemptively. Of the patients, 85 were already on either hemodialysis or peritoneal dialysis therapy at the time of transplantation. The white blood cell count value of the patient and control group (7246.72 ± 1460.26 and 76661.76 ± 1286.29, respectively; P = .43), NLR of the control group was significantly lower than patient group (1.98 ± 0.94 and 3.47 ± 2.33, respectively; P = .007). The NLR of the preemptive group was decreased substantially at the end of first year posttransplantation, the NLR of the preemptive group was significantly lower than the nonpreemptive group (3.08 ± 1.32 and 3.71 ± 2.33; P = .01). CONCLUSIONS We showed that all ESRD patients had an increased inflammation rate according to CRP and NLR when compared with healthy controls. We also found that improvement of inflammatory state in preemptive patients is significantly better than nonpreemptive patients at the end of first year evaluation.


Peritoneal Dialysis International | 2014

A Rare Cause of Peritoneal Dialysis-Related Peritonitis: Achromobacter denitrificans

Erdem Çankaya; Mustafa Keles; Erim Gulcan; Abdullah Uyanik; H. Uyanik

boplastin time were within normal limits. Examination of the effluent showed no leukocytes. The patient was treated conservatively: Vital signs were closely monitored, and 2 transfusions and analgesics were given. Dialysate exchanges remained bloody during the following hours. The next day, an ecchymosis on the abdomen began to be obvious. During the subsequent days, exchanges became clearer, the ecchymosis grew greater (Figure 2), and the patient’s symptoms improved. Her vital signs were stable. On day 5 of hospitalization, the patient was mobilized and discharged. Peritoneal dialysis provides a window to the peritoneum. Hemoperitoneum is a well-recognized complication in PD. Menstruation, catheter-related malfunctions, and intra-abdominal pathology of solid organs and the gastrointestinal tract are the most common causes (1). Rectus sheath hematoma (RSH) is an uncommon condition in the general population, usually being a complication of abdominal trauma or surgery. Spontaneous RSH is often a complication of the increasing use of anticoagulant therapies combined with excessive strain on the abdominal muscles (2). In PD patients, RSH has only rarely been described as a complication of PD catheter insertion (3). Hemoperitoneum as first presentation of RSH in a prevalent PD patient has not yet been described in the literature. There were questions about the cause of the hematoma in our patient. She had never received antiplatelet or anticoagulant therapy. Clinically, systemic lupus erythematosus is associated with bleeding when the platelet count is less than 20 000/μL or when antibodies against factor VIII are apparent [in which case, partial thromboplastin time is increased (4)]. In our patient, platelet count and partial thromboplastin time were within normal limits. She had taken corticosteroids for long intervals in the past, but corticosteroids are not associated with bleeding disorders. One common complication of chronic corticosteroid use is myopathy and skin thinning. Although the hematoma was close to the catheter, no trauma to the catheter was reported. That background, plus the increased abdominal strain caused by a tense cough, might explain the hematoma.


Transplantation proceedings | 2015

High-Grade Inflammation in Renal Failure Patients, According to Mean Platelet Volume, Improves at the End of Two Years After Transplantation

Yusuf Bilen; Erdem Çankaya; M. Keleş; Abdullah Uyanik; Bulent Aydinli; Nurhan Bilen

BACKGROUND Chronic kidney disease (CKD) is a worldwide disorder which is characterized by the presence of systemic low-grade inflammation. There is also acquired immune deficiency in this patient group which is clinically present with increased incidence of severe infections, poor response to vaccination, and increased risk of virus-associated cancers. Renal transplantation is one of the renal replacement modalities that restore renal functions. Mean platelet volume (MPV) is emerging as a marker of inflammation in many clinical conditions. In this study we aimed to disclose the improvement of paired immune response of ESRF patients after renal transplantation even though they are under immunosuppressive therapy. METHODS We retrospectively investigated C-reactive protein, MPV, platelets (PLT), and other hematologic parameters on the day of transplantation and at the end of the 1st and 2nd years after transplantation of 58 preemptive and 112 nonpreemptive renal transplant patients. We compared them with a healthy control group. RESULTS The MPV of the control group was 8.00 ± 0.73. The mean MPV of transplant patients before transplantation and at the end of the 1st and 2nd years after transplantation were 7.66 ± 1.01, 8.06 ± 0.97, and 8.20 ± 0.84, respectively. The initial MPV of the patient group was statistically significantly lower than the control group (P = .04). There was a statistically significant increase of MPV after transplantation. At the end of the 2nd year the difference of MPV between the patient and control groups was gone. CONCLUSIONS We detected that CKD patients had a decreased MPV compared with normal individuals and that it normalized at the end of the 2nd year after renal transplantation. We speculated that the decreased MPV in CKD patients is related to increased inflammation and uremic toxins owing to uremia which was improved after renal transplantation.


Acta Radiologica | 2017

Value of dynamic MRI using the Ktrans technique for assessment of native kidneys in pre-emptive renal transplantation.

Recep Sade; Mecit Kantarci; Leyla Karaca; Aylin Okur; Hayri Ogul; Mustafa Keles; Erdem Çankaya; Arif Kursad Ayan

Background Different non-invasive imaging techniques such as Doppler ultrasonography and renal scintigraphy are commonly employed to assess allograft function and associated complications. However, all such methods lack sufficient specificity to discriminate between residual renal function of native kidneys. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) evaluates signal dynamics during the passage of contrast material through the renal cortex, medulla, and collecting system. Purpose To investigate the value of DCE 3T MRI using a quantitative pharmacokinetic parameter (Ktrans) for the assessment of native kidneys before and after pre-emptive renal transplantation. Material and Methods Twenty-five consecutive patients with end-stage renal disease underwent DCE MRI before and 6 months after kidney transplantation. MRI was performed using a 3T scanner. Regions of interests were drawn over each kidney, encompassing the cortex and medulla but excluding the collecting system and any coexisting cysts. Parametric Ktrans values were automatically generated. Results In the pre-transplantation group, mean Ktrans values for the right and left kidneys were 0.55 ± 0.09 min–1 and 0.44 ± 0.15 min–1, respectively. In the post-transplantation group, mean Ktrans values of the right and left kidneys were 0.27 ± 0.07 min–1 and 0.25 ± 0.10 min–1, respectively. There were statistically significant differences between right and left kidneys in terms of mean Ktrans values in the pre- and post-transplantation groups (P < 0.001). Conclusion Our preliminary results show that native kidneys were still functioning 6 months after transplantation. MR perfusion using Ktrans may constitute a non-invasive means of determination of the viability of native kidneys after renal transplantation.


Progress in Transplantation | 2016

Vitamin D Treatment Effect on Serum Endocan and High-Sensitivity C-Reactive Protein Levels in Renal Transplant Patients

Omer Atis; Mustafa Keles; Erdem Çankaya; Hasan Dogan; Hülya Aksoy; Fatih Akcay

Context: Endocan is a marker showing endothelial dysfunction and inflammation. Significantly increased endocan levels have been observed in serum of patients with sepsis and cancer. Objective: Our aim was to investigate the relationship between vitamin D treatment and serum endocan and high-sensitivity C-reactive protein (hs-CRP) levels as inflammatory markers in transplant patients. Design: Prospective. Setting: Nephrology clinic. Patients: Thirty-eight renal transplant patients with serum 25-hydroxy-vitamin D (25-OH-vitamin D) levels below 20 ng/mL and transplanted at least 12 months. Intervention: One-time oral dose of 300 000 IU vitamin D3. Main Outcome Measures: Before and after vitamin D treatment, serum endocan, hs-CRP, calcium, phosphorus, and parathyroid hormone (PTH) levels were measured. Results: Median serum endocan and PTH values before vitamin D were significantly higher than those of after treatment values (P = .001 and P < .001, respectively). On the other hand, serum total calcium and phosphorus levels before vitamin D treatment were lower than the values obtained after vitamin D treatment (P = .0013 and P < .001, respectively). Serum hs-CRP was lower after vitamin D therapy than before, but the difference was not statistically significant (P = .06). A moderate negative correlation was determined between endocan and 25-OH-vitamin D levels after treatment with vitamin D (r = −.36, P = .02). Conclusion: This study has revealed that vitamin D treatment reduced markers of endothelial dysfunction in patients with renal transplantation and vitamin D deficiency.


Saudi Journal of Kidney Diseases and Transplantation | 2016

The effects of dual and triple combinations of trandolapril, telmisartan, and verapamil on overt proteinuria in the patients with diabetic nephropathy.

Bulent Albayrak; Erdem Çankaya; Ramazan Cetinkaya; Serkan Cerrah; Yusuf Bilen

Diabetic nephropathy (DN) is one of the most important causes of the end-stage renal failure and its prevalence is found to be increasing. The presence of hypertension and progressive proteinuria is among the important findings. In this study, the effects of double and triple combinations of trandolapril, telmisartan, and verapamil on proteinuria were investigated in diabetic patients with nephropathy. Seventy-eight patients (mean age: 56.11 ± 11.26 years; 47 females and 31 males) with overt proteinuria and DN were included in this study. The patients were divided into four groups: Group I (n: 18, trandolapril + telmisartan), Group II (n: 20, trandolapril + verapamil), Group III (n: 20, trandolapril +telmisartan + verapamil), and Group IV (n: 20, telmisartan + verapamil). At the end of a three-month therapy, within and between group comparisons were done about the effects of the use of double or triple drug combinations on proteinuria, glomerular filtration rate (GFR), electrolytes, serum albumin, low-density lipoprotein (LDL)- cholesterol, and HbA1C. There was no significant difference among groups in terms of age, gender, diabetes duration, body mass index, and retinopathy frequency. The decreases in proteinuria and mean arterial blood pressure (MABP) were significant in all groups. The decrease in proteinuria was independent of the decrease in MABP [the reduction rate in proteinuria was 39% (P <0.001) in Group I, 37% (P <0.001) in Group II, 42% (P <0.001) in Group III, and 43% (P <0.001) in Group IV; the reduction rate in MABP was 10.6% (P <0.001) in Group I, 13.7% (P <0.001) in Group II, 17.5% (P <0.001) in Group III, and 15.4% (P <0.001) in Group IV]. Decrease in HbA1C (before and after treatment) was significant in Groups III and IV when com- pared to Groups I and II. Any adverse event, like hyperkalemia, was not observed. There was no significant difference among the groups in terms of GFR, LDL-cholesterol, albumin, and potassium. All the patients tolerated the drugs well. In conclusion, in patients with DN, both double or triple combinations of trandolapril, telmisartan and verapamil resulted in significant decreases in proteinuria and MABP. Triple combinations did not have any superiority over double combinations. Therefore, the suitable drug combinations may be chosen according to the clinical status of a patient.


Clinical Radiology | 2016

Non-contrast-enhanced imaging of haemodialysis fistulas using quiescent-interval single-shot (QISS) MRA: a feasibility study

Aylin Okur; Mecit Kantarci; Leyla Karaca; Sema Yildiz; Recep Sade; Berhan Pirimoglu; Mustafa Keles; A. Avci; Erdem Çankaya; Peter Schmitt

AIM To assess the efficiency of a novel quiescent-interval single-shot (QISS) technique for non-contrast-enhanced magnetic resonance angiography (MRA) of haemodialysis fistulas. MATERIALS AND METHODS QISS MRA and colour Doppler ultrasound (CDU) images were obtained from 22 haemodialysis patients with end-stage renal disease (ESRD). A radiologist with extensive experience in vascular imaging initially assessed the fistulas using CDU. Two observers analysed each QISS MRA data set in terms of image quality, using a five-point scale ranging from 0 (non-diagnostic) to 4 (excellent), and lumen diameters of all segments were measured. RESULTS One hundred vascular segments were analysed for QISS MRA. Two anastomosis segments were considered non-diagnostic. None of the arterial or venous segments were evaluated as non-diagnostic. The image quality was poorer for the anastomosis level compared to the other segments (p<0.001 for arterial segments, and p<0.05 for venous segments), while no significant difference was determined for other vascular segments. CONCLUSION QISS MRA has the potential to provide valuable complementary information to CDU regarding the imaging of haemodialysis fistulas. In addition, QISS non-enhanced MRA represents an alternative for assessment of haemodialysis fistulas, in which the administration of iodinated or gadolinium-based contrast agents is contraindicated.

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