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Featured researches published by Yener Koc.


Kidney & Blood Pressure Research | 2012

Relationship of Fibroblast Growth Factor 23 with Left Ventricle Mass Index and Coronary Calcificaton in Chronic Renal Disease

Abdulkadir Unsal; Sennur Kose Budak; Yener Koc; Taner Basturk; Tamer Sakaci; Elbis Ahbap; Ayse Sinangil

Background: to evaluate the relationship between FGF23 and changes in biochemical parameters, left ventricle mass index, coronary, aortic and, valve calcifications. Methods: Totally 185 patients with chronic renal disease were included in this prospective, cross-sectional study. The patients were stratified according to GFR levels (mL/min/1.73m2) into 5 groups: ≥60, 45-59, 30-44, 15-29 and <15 (group 1-5 respectively).Biochemical parameters, serum FGF23 levels were measured. Echocardiographic assessments and Coronary artery calcification (CAC) with multidetector computerized tomography (MDCT) were done, left ventricle muscle mass (LVMI) was measured all patients. Results: Left ventricular hypertrophy (LVH), aortic and valve calcification were detected in 27.8%, 25.3% and 12% of patients respectively. CAC was detected in 18 patients. LVMI and FGF23 levels were found to increase proportionally with the severity of renal failure. A significant positive correlation between FGF-23 level and serum phosphate, logPTH, and CaxP product was found. While a correlation between FGF-23 and valve calcification was detected, no correlation could be detected with LVMI, LVH, coronary and aortic calcification. Conclusion: In CKD, circulating FGF-23 and LVMI levels gradually increase with declining renal function such that by the time patients reach end-stage renal disease. Correlation between logFGF23 and valve calcification was significant, whereas no statistically significant relationship was found between logFGF23 and LVMI, LVH, aortic and coronary artery calcifications.


Renal Failure | 2011

Impact of Volume Status on Blood Pressure and Left Ventricle Structure in Patients Undergoing Chronic Hemodialysis

Yener Koc; Abdulkadir Unsal; Hasan Kayabasi; Erkan Oztekin; Tamer Sakaci; Elbis Ahbap; Murvet Yilmaz; Ali Oğuz Akgün

In this study, we aimed to examine the impact of volume status on blood pressure (BP) and on left ventricular mass index (LVMI) in chronic hemodialysis (HD) patients. This study enrolled 74 patients (F/M: 36/38, mean age 53.5 ± 15.3 years, mean HD time 41.5 ± 41 months) that were on HD treatment for at least 3 months. Demographics, biochemical tests, hemogram and C-reactive protein levels, mean interdialytic weight gain (IDWG), mean percentage of ultrafiltration (UF), and intradialytic complications such as hypotension and cramps were determined. Mean values of predialysis and postdialysis BP measurements were recorded a month before echocardiographic examination. On the day after a midweek dialysis session, 24 h ambulatory BP monitoring (ABPM) and echocardiographic examination were made concurrently. The patients were classified into two groups according to volume status: normovolemic (group 1; 14F/24M, mean age 50 ± 16.7 years, mean dialysis time 47.7 ± 47.7 months) and hypervolemic (group 2; 15F/21M, mean age 57.3 ± 12.7 years, mean dialysis time 34.9 ± 32 months). HD duration, IDWG, UF, and interdialytic complication rates were similar between the two groups (p < 0.05). Eleven patients (28.9%) of group 1 and 8 patients (22.2%) of group 2 showed dipper (p = 0.50). Valvular damage was more common in group 2 (p = 0.002). Whereas 33 patients (91.7%) had left ventricular hypertrophy (LVH) in group 2, 21 patients of the group 1 (55.3%) had LVH (p < 0.001). Although LVMI showed a significant positive correlation with cardiothoracic index, predialysis and postdialysis BP, IDWG, UF, daytime and nighttime BP measurements of 24 h ABPM, a significant negative correlation was seen with Kt/V urea and serum albumin levels. In conclusion, increased IDWG and UF and elevated BP are independent predictors of LVH for HD patients. Increased volume status leads to IDWG and elevated BP and eventually causes severe LVMI increases.


Journal of Infection in Developing Countries | 2013

Tuberculosis in dialysis patients: a nine-year retrospective analysis

Abdulkadir Unsal; Elbis Ahbap; Taner Basturk; Yener Koc; Tamer Sakaci; Ayse Sinangil Arar; Hasan Kayabasi; Mustafa Sevinc

INTRODUCTION Diagnosis of tuberculosis (TB) among dialysis patients may be difficult because of increased frequency of extra-pulmonary presentations, atypical clinical manifestations, and non-specific symptoms. This study aimed to investigate the spectrum of clinical presentations and outcome in dialysis patients during a nine-year period. METHODOLOGY A total of 651 patients undergoing hemodialysis (HD) and peritoneal dialysis (PD) for at least three months in our unit between 2001 and 2010 were studied. Dialysis and follow-up were performed in our tertiary care center located in the eastern region of Turkey. Diagnosis of TB was established by combining clinical, radiological, biochemical, microbiological, and histological findings. Choice of anti-TB drug used, the results of therapy, and patient outcome were noted. RESULTS Out of 651 dialysis patients studied, 322 (49.4%) were on PD and the remainder on HD (50.6%). Twenty-six (4%) of the 651 dialysis patients were diagnosed with TB (15 PD, 11 HD), 5 of whom were diagnosed by microbiological assessment, 9 by pathological assessment, and 12 by clinical and radiological findings. Mean age at diagnosis was 41.5 ± 16.5 years and the female/male ratio was 1.18. Three patients had a history of pulmonary TB. Extra-pulmonary involvement was observed in 17 (65.4%) patients. All patients were treated with rifampicin isoniazid, ethambutol, pyrazinamide and pyridoxine. Four patients died during the study. CONCLUSION TB occurred in dialysis patients and extra-pulmonary TB was more commonly identified than pulmonary TB. Tuberculous lymphadenitis was the most frequent form of extra-pulmonary TB in our cohort.


Renal Failure | 2012

Evaluation of Resistive Index by Color Doppler Imaging of Orbital Arteries in Type II Diabetes Mellitus Patients with Microalbuminuria

Taner Basturk; Ramazan Albayrak; Turgay Ulas; Mehmet Akcay; Abdulkadir Unsal; Mehmet Toksoy; Yener Koc

Objective: Resistive index (RI) is an indirect measurement of blood flow resistance that can be used to evaluate vascular damage in ophthalmologic diseases. The purpose of this study was to evaluate the association between RI values of orbital arteries by using the color Doppler imaging (CDI) in type II diabetes mellitus (DM) patients with microalbuminuria. Patients and methods: We evaluated 91 type II DM patients with microalbuminuria and 27 healthy subjects. The DM patients with microalbuminuria were grouped into two: group 1 consisted of patients with retinopathy (n = 51) and group 2 consisted of patients without retinopathy (n = 40). Healthy subjects constituted group 3 (n = 27). The mean RI values of ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery (PCA) were measured using CDI. Results: Compared to diabetic group 2, group 1 had significantly higher mean RIs of OA, CRA, PCA, and HbA1c levels (p < 0.001 for all). Besides, there were no statistical differences in mean RIs of OA, CRA, and PCA between the control group and group 2 (p = 1.0; p = 0.44; p = 0.67, respectively). Mean RIs of OA and PCA were significantly correlated with age in group 1 (r = 0.549, p < 0.001; r = 0.407, p = 0.003, respectively). Mean RI of CRA was significantly correlated with the duration of diabetes and age in group 1 (r = 0.296, p = 0.035; r = 0.486, p < 0.001, respectively). Conclusion: Our study indicates that RI might be a useful marker for early diagnosis and follow-up of diabetic retinopathy, and orbital RI assessment would be beneficial for diabetic patients with retinopathy.


Kidney & Blood Pressure Research | 2012

Correlation between the resistive index values of renal and orbital arteries.

Taner Basturk; M. Akcay; R. Albayrak; Abdulkadir Unsal; T. Ulas; Yener Koc

Background: Resistive index (RI) is an indirect measurement of blood flow resistance that can be used to evaluate vascular damage. Aims: The purpose of this study is to evaluate the association between RI values of orbital and intrarenal arteries by means of Doppler ultrasonography (US). Methods: We evaluated 103 diabetic patients. As a control group, 30 subjects were examined. The patients were divided into two groups. Group 1 consisted of patients with urinary albumin excretion (UAE) <300 mg/day and estimated glomerular filtration rate (eGFR) levels >90 ml/min (n = 50); Group 2 had a UAE >300 mg/day and/or eGFR levels between 89 and 60 ml/min (n = 53). The association between RI values obtained with Doppler US of the ophthalmic artery, central retinal artery, posterior ciliary artery and intrarenal arteries were calculated. Results: Both orbital and intrarenal arterial RI values in Group 1 and Group 2 were higher than the control group (p = 0.001); furthermore, values were higher in Group 2 than in Group 1 (p = 0.0004/0.029/0.036, p = 0.016, respectively). A positive correlation was found between orbital and intrarenal arterial RI values in Group 2 (r = 0.475, 0.285, 0.363, p < 0.01, respectively). Conclusion: Both orbital and renal arterial RI values were shown to be higher than the control group. Further, a trend towards higher RI values was observed with renal disease. RI may be useful as one of the markers for early diagnosis and follow-up of diabetic nephropathy and retinopathy.


Clinical Nephrology | 2015

Relationship between relative interdialytic weight gain and serum leptin levels, nutrition, and inflammation in chronic hemodialysis patients

Elbis Ahbap; Tamer Sakaci; Ekrem Kara; Tuncay Sahutoglu; Yener Koc; Taner Basturk; Mustafa Sevinc; Cuneyt Akgol; Arzu Ozdemir Kayalar; Zuhal Atan Ucar; Feyza Bayraktar; Abdulkadir Unsal

INTRODUCTION Excessive relative interdialytic weight gain (RIDWG, %) is an important risk factor for long-term adverse cardiovascular outcomes in chronic hemodialysis (HD) patients. On the other hand, it may also be an index of good appetite and nutritional status. We aimed to assess the relationship between RIDWG and appetite, nutrition, inflammation parameters of chronic HD patients. METHODS 100 chronic anuric HD patients were enrolled in this prospective study between January 2013 and January 2014. Patients with hospitalization, major surgery, obvious infectious/inflammatory disease, end-stage liver disease, malignancies, and malabsorption syndromes were excluded. Patients were divided into 3 groups according to their RIDWG levels; group 1 = RIDWG < 3%, group 2 = RIDWG: 3 - 5%, and group 3 = RIDWG > 5%. RESULTS Group 3 patients were younger (p = 0.011) and had a lower body mass index (BMI) (p = 0.014). Nutrition and inflammation parameters including malnutrition inflammation score (MIS), serum albumin, prealbumin, triceps skinfold thickness, hs-CRP, and TNF-α ere not significantly different between the groups. Leptin and leptin/BMI ratio were significantly lower in group 3 (p = 0.001). RIDWG was negatively correlated with age (p = 0.001, r = -0.371), BMI (p = 0.001, r = -0.372), leptin (p = 0.001, r = -0.369), leptin/BMI (p = 0.001, r = -0.369). After adjustment for BMI in linear regression analyis, leptin/BMI remained significantly correlated with RIDWG (p = 0.024). CONCLUSION This study revealed that RIDWG was associated with younger age, lower BMI and dry weight, and lower serum leptin levels. More detailed studies are needed to validate and dissect the mechanisms of these findings.


Journal of Renal Care | 2011

Clinical outcome of diabetic peritoneal dialysis patients and evaluation of factors affecting mortality: a single centre's experience from Turkey.

Yener Koc; Abdulkadir Unsal; Elbis Ahbap; Tamer Sakaci; Murvet Yilmaz

The purpose of this study is to analyse the outcome of the diabetic peritoneal dialysis (PD) patients and compare the findings of those remaining on treatment with those who withdrew from treatment. Participants were 61 patients starting PD between 2001 and 2009, data were evaluated retrospectively. PD treatment was withdrawn in 48 patients forming Group 1 = drop-out; 26 F, mean age 59 ± 13 years; 13 patients in Group 2 = treatment; 4 F, mean age 50 ± 10 years, still receiving PD therapy. Demographics, laboratory and blood pressure data were compared in both groups. The causes for withdrawal were: death (54%), transfer to HD (33%), other causes (13%). Most frequent cause of death: cardiac events (57.7%), peritonitis and/or sepsis (38,4%). Transfer to HD - peritonitis (50%), insufficient PD (50%). Most frequent cause of peritonitis was Staph. Aureus in 42 instances in Group 1. We found positive correlation between mortality and age (p:0.008, r:0,345) and negative correlation between mortality and follow-up time, pretreatment albumin, calcium and PTH, systolic and diastolic BP in the last follow-up appointment. Cardiovascular events and peritonitis were the most important causes of withdrawal of patients. The presence of hypo-parathyroidaemia, hypocalcaemia and hypo-albuminaemia were associated with mortality.


Nefrologia | 2012

Is there impact of mortality prior hemodialysis therapy in peritoneal dialysis patients

Yener Koc; Abdulkadir Unsal; Taner Basturk; Tamer Sakaci; Elbis Ahbap-Dal; Ayse Sinangil-Arar; Sennur Kose-Budak; Hasan Kayabasi

AIM The aim of this study is to investigate the mortality and the factors which may affect it in patients who were transferred to peritoneal dialysis (PD) from hemodialysis (HD), compared to patients assigned to PD as first-line therapy. MATERIAL AND METHODS A total of 322 patients treated with PD between 2001 and 2010 were evaluated retrospectively. Twenty three patients were excluded and the data of remaining 299 patients (167F, mean follow up time 38.5±26.8 months, mean age 44.7±15.9 years) were evaluated. Patients were separated into two groups according to their HD history. Group 1 and group 2 consisted of patients with (n=48) and without (n=251) a history of prior HD, respectively. Socio-demographic characteristics such as who helped administer the PD and the preference of patients (compulsory vs their preference) were obtained from the patient records. The clinical data obtained during the last clinical evaluation before the initiation of PD (blood pressure, daily urine volumes, daily ultrafiltration amounts and laboratory parameters) were recorded. Additional systemic diseases and information about the etiologies of the end stage renal disease (ESRD) of all patients were recorded. Frequencies of the infectious complications were recorded. Patient and technique survival were investigated and compared between groups. RESULTS In group 1, the patients were older and had less urine amounts (p=0.028 and 0.041 respectively). Thirty five patients (70%) and 25 patients (9.3%) have been transferred to PD due to vascular problems in group 1 and 2, respectively (p<0.001). In group 1, 37 (74%) patients were carrying out PD treatment by themselves, compared to 222 (88.4%) patients in group 2 (p=0.016). Incidences of peritonitis and catheter exit site/tunnel infection attacks were found 24.9±26.8 and 27.2±26.5 patient-months in group 1, and 27.4±22.4 and 33.4±24.5 patient-months in group 2, respectively (p=0.50 and 0.12). In group 1, twenty three patients have death and 2 patients have discontinued the treatment due to transplantation. In group 2, 174 patients have discontinued the treatment (55 patients have died, 80 patients have been switched to hemodialysis and 39 patients have received renal transplantation). There were significant differences between groups according to the last condition (p<0.001). Mean patient survival were found 22.9±4.2 and 55.5±2.8 patient-months in group 1 and group 2, respectively. The patient survival rates by Kaplan-Meier analysis were 50%, 40.9%, 27.3% and 9.1% at 1, 2, 3, and 4 years in group 1 and 90.9%, 81.6%, 73.9%, 64.9% and 53.1% at 1, 2, 3, 4 and 5 years in group 2, respectively. The mortality rate is higher in patients who have undergone HD before PD compared without HD history (log rank:<0.001). In the Cox proportional hazards model analysis, preference of PD (RR: 7.72, p<0.001), presence of diabetes (RR: 2.26, p=0.01), pretreatment serum albumin level (RR: 0.37, p<0.001) and catheter exit size infection attacks (RR:0.34, p=0.01) were identified as predictors of mortality. CONCLUSION Our data show that mortality in patients transferred to PD from HD was higher than in patients undergoing PD as first-line therapy. Compulsory choice such as vascular access problems and social factors were the most important causes of increasing mortality in patients transferred to PD from HD.


Renal Failure | 2012

Factors Associated with Above and Under 5-Year Survival in Peritoneal Dialysis Patients

Abdulkadir Unsal; Taner Basturk; Yener Koc; Ayse Sinangil; Elbis Ahbap; Tamer Sakaci; Mustafa Sevinc; Arzu Ozdemir Kayalar

Background/aims: A few patients stay on peritoneal dialysis (PD) for 5 years or longer from initiation of therapy. We investigated patient survival and factors affecting mortality in PD patients. Methods: This was a retrospective study including 354 PD patients. The demographic, clinical, and biochemical data were collected from the medical records. Two hundred patients were excluded. Evaluation was carried out on data from 154 patients, including 83 surviving 5 years or more and 71 who were taken as surviving less than 5 years. Results: Mean age, number of comorbid diseases, prevalence of diabetes mellitus (DM), rate of mandatory preference of PD, making their PD exchanges with help from anyone were lower in surviving patients, and education level was higher in surviving patients. Advanced age, high rate of mandatory preference of PD, high rate of baseline high, and high-average peritoneal transporters were associated with an increased risk of death. Conclusion: Long-term survival is possible for PD patients, particularly nondiabetics, those having higher education level, those with a self-preference of PD, and those making PD exchanges without any help.


Clinics | 2012

The effects of angiotensin-converting enzyme inhibitors on peritoneal protein loss and solute transport in peritoneal dialysis patients

Taner Basturk; Abdulkadir Unsal; Yener Koc; Eren Nezaket; Elbis Ahbap; Tamer Sakaci; Mustafa Sevinc

OBJECTIVE: The objective of this study was to examine the effects of angiotensin-converting enzyme inhibitors on peritoneal membrane transport, peritoneal protein loss, and proteinuria in peritoneal dialysis patients. METHODS: Fifty-four peritoneal dialysis patients were included in the study. The patients were divided into two groups. Group 1 (n = 34) was treated with angiotensin-converting enzyme inhibitors. Group 2 (n = 20) did not receive any antihypertensive drugs during the entire follow-up. Eleven patients were excluded from the study thereafter. Thus, a total of 30 patients in Group 1 and 13 patients in Group 2 completed the study. We observed the patients for six months. Group 1 patients received maximal doses of angiotensin-converting enzyme inhibitors for six months. Parameters at the beginning of study and at the end of six months were evaluated. ClinicalTrial.gov: NCT01575652. RESULTS: At the end of six months, total peritoneal protein loss in 24-hour dialysate effluent was significantly decreased in Group 1, whereas it was increased in Group 2. Compared to the baseline level, peritoneal albumin loss in 24-hour dialysate effluent and 4-hour D/P creatinine were significantly increased in Group 2 but were not significantly changed in Group 1. A covariance analysis between the groups revealed a significant difference only in the decreased amount of total protein loss in 24-hour dialysate. Proteinuria was decreased significantly in Group 1. CONCLUSION: This study suggests that angiotensin-converting enzyme inhibitors reduce peritoneal protein loss and small-solute transport and effectively protect peritoneal membrane transport in peritoneal dialysis patients.

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Ayse Sinangil

Istanbul Bilim University

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Ekrem Kara

Recep Tayyip Erdoğan University

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