Kaan Okyay

Baskent University, Engüri, Ankara, Turkey

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Publications (41)84.71 Total impact

  • The American Journal of Cardiology 03/2015; 115:S118. DOI:10.1016/j.amjcard.2015.01.403 · 3.43 Impact Factor
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    ABSTRACT: Epicardial adipose tissue (EAT) is a cardiovascular risk predictor in general population. However, its value has not been well validated in maintainance hemodialysis (MHD) patients. We aimed to assess associations of EAT with cardiovascular risk predictors in nondiabetic MHD patients. In this cross-sectional study, we measured EAT thickness by transthoracic echocardiography in 50 MHD patients (45.8 ± 14.6 years of age, 37 male). Antropometric measurements, bioimpedance analysis, left ventricular (LV) mass, carotis intima media thickness, blood tests, homeostasis model assessment for insulin resistance (HOMA-IR) and hemodialysis dose by single-pool urea clearence index (spKt/V) were determined. The mean EAT thickness was 3.28 ± 1.04 mm. There were significant associations of EAT with body mass index (β = 0.590, P < 0.001), waist circumference (β = 0.572, P < 0.001), body fat mass (β = 0.562, P < 0.001), percentage of body fat mass (β = 0.408, P = 0.003), percentage of lean tissue mass (β = −0.421, P = 0.002), LV mass (β = 0.426, P = 0.002), carotis intima media thickness (β = 0.289, P = 0.042), triglyceride/high-density lipoprotein cholesterol ratio (β = 0.529, P < 0.001), 1/HOMA-IR (β = −0.386, P = 0.006), and spKt/V (β = −0.311, P = 0.028). No association was exhibited with visfatin C, high-sensitivity C-reactive protein, interleukin-6, and tumor necrosis factor-alpha (for all, P > 0.05). Body mass index, waist circumference, body fat mass, percentage of lean tissue mass, LV mass, triglyceride/high-density lipoprotein cholesterol ratio, HOMA-IR, and spKt/V appeared as independent predictors of EAT. EAT was significantly associated with body fat measures, cardiovascular risk predictors, and dialysis dose in MHD patients.
    Hemodialysis International 03/2015; DOI:10.1111/hdi.12276 · 1.44 Impact Factor
  • The American Journal of Cardiology 03/2015; 115:S36. DOI:10.1016/j.amjcard.2015.01.127 · 3.43 Impact Factor
  • The American Journal of Cardiology 03/2015; 115:S117. DOI:10.1016/j.amjcard.2015.01.400 · 3.43 Impact Factor
  • The American Journal of Cardiology 03/2015; 115:S88-S89. DOI:10.1016/j.amjcard.2015.01.346 · 3.43 Impact Factor
  • Kaan Okyay, Aylin Yıldırır
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    Anadolu kardiyoloji dergisi: AKD = the Anatolian journal of cardiology 10/2014; 14(Supplement 1):14. · 0.72 Impact Factor
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    ABSTRACT: Background – Epicardial adipose tissue (EAT) is a local source of various hormones, cytokines and vasoactive substances affecting the myocardium. EAT contains abundant ganglionic plexi that interact with the autonomic nervous system. Evidence of the association between EAT and arrhythmia is limited, with the exception of atrial fibrillation. This study aimed to investigate the relation between EAT and cardiac autonomic function using heart rate variability (HRV) and heart rate turbulence (HRT) parameters. Methods – All subjects underwent a 24-hour Holter recording to assess HRV and HRT parameters and a transthoracic echocardiography to measure EAT thickness. Patients were divided into 2 groups according to the median EAT thickness (3.9 mm). The higher EAT group consisted of 111 patients with a >3.9 mm thickness and the lower EAT group 113 patients with a ≤3.9 mm EAT thickness. Results – HRV and HRT parameters were significantly influenced in the higher EAT group. Moreover, we observed significant correlations between EAT thickness and Holter findings (SDNN: r = -0.462, p <0.001; SDNN index: r = -0.349, p <0.001; SDANN: r = -0.465, p <0.001; RMSSD: r = -0.251, p <0.001; pNN50: r = -0.354, p <0.001; turbulence onset: r = 0.172, p = 0.010; turbulence slope: r = -0.279, p <0.001, HRT category: r = 0.169, p = 0.011). In multivariate regression analysis, EAT thickness was independently associated with all measures of HRV and HRT, with the exception of turbulence onset. Conclusions – Sympathovagal imbalance, detected by HRV and HRT parameters, is related to EAT thickness. As sympathovagal imbalance is a predictor of arrhythmic events, EAT may play an important arrhythmogenic role not limited to atrial fibrillation.
    Pacing and Clinical Electrophysiology 07/2014; DOI:10.1111/pace.12512 · 1.75 Impact Factor
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    ABSTRACT: Introduction: The significant improvement in life expectancy resulted in an increasingly older population in almost all regions of the world, which necessitated adequate knowledge and therapeutic measures involving the problems of the elderly. Cardiovascular system as well as other organs is greatly affected by aging. Therefore, optimal cut-off values are required to distinguish physiologic changes from pathologic processes. Currently, there is not enough echocardiographic information regarding aging-associated changes in the octogenarian population. We aimed to characterize echocardiographic measures of structure and function among a group of healthy octogenarians. Material and Methods: We screened approximately 350 octogenarians, residing in nursing homes, during a 3-year period. Subjects with history of atherosclerotic heart disease, previous myocardial infarction, atrial fibrillation, hypertension, diabetes mellitus, permanent pacemaker, obesity (BMI >=30 kg/m2), known thyroid disorders, chronic systemic disorders, and current smoking were excluded. We identified 60 subjects, 20 of whom were also excluded due to moderate-severe valve disease, segmental/global kinesis abnormalities, pulmonary hypertension, and poor acoustic window. Therefore, we included 40 healthy subjects at 80 to 89 years age (mean age 83.8 ± 2.8), including 27 females (%67.5) and 13 (% 32.5) males. Healthy was defined as being able to do daily activities without any help, medication and symptoms. Our subjects had Class I functional capacity according to New York Heart Association. The subjects underwent standard echocardiographic and tissue Doppler imaging according to guidelines of the American Society of Echocardiography (ASE). All measurements were indexed by dividing to body surface area (BSA) for standardization. Results: Left ventricular mass, posterior wall thickness, right ventricular diameter, tricuspid E/A ratio and septal e’ wave velocity were significantly higher in men, which lost significance after adjusting for BSA. Moreover, mild global left and right ventricular dysfunction including a prominent diastolic counterpart however with normal ejection fraction was revealed using conventional and tissue Doppler techniques. Lastly, we checked our results with the current reference values of the ASE and observed the following differences: ventricular septum, relative wall thickness, left ventricular mass and mass index values were above ASE reference range, posterior wall measurements were close to upper range. On the contrary, left ventricular diameters and volumes were below ASE reference range (Table 1). Discussion: We examined echocardiographic measures of structure and function of the heart among a group of healthy octogenarians. Moreover, we obtained reference range, mean and 95% confidence interval values derived from conventional and tissue Doppler examination specific to this age group.
    The American Journal of Cardiology 03/2014; 113(7, Supplement):31-32. · 3.43 Impact Factor
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    ABSTRACT: Currently, there is not enough echocardiographic information regarding aging-associated changes in the octogenarian population. We aimed to characterize echocardiographic measures of structure and function among a group of healthy octogenarians. Approximately 350 octogenarians, residing in nursing homes, were screened in Ankara, Turkey. According to inclusion criteria, 40 octogenarians were enrolled. These subjects underwent conventional and tissue Doppler echocardiography according to the guidelines of the American Society of Echocardiography (ASE). The population was also separated into various groups according to gender, body mass index (BMI, <25 vs. 25-29.9), and blood pressure (<80/120 mmHg vs. 80-89/120-139 mmHg). All measurements were indexed by dividing to body surface area (BSA) for standardization. Left ventricular mass (LVM), posterior wall thickness, right ventricular diameter, tricuspid E/A ratio, and septal e'-wave velocity were significantly higher in men, which lost significance after adjusting for BSA. There was no significant difference between groups formed by BMI and blood pressure. Moreover, mild global left and right ventricular dysfunction including a prominent diastolic counterpart, however, with normal ejection fraction was revealed using conventional and tissue Doppler techniques. Finally, we checked our results with the current reference values of the ASE and observed the following differences: ventricular septum, relative wall thickness, LVM, and mass index values were above ASE reference range, posterior wall measurements were close to upper range. On the contrary, left ventricular diameters and volumes were below ASE reference range. We described echocardiographic measures of structure and function in a group of healthy octogenarians.
    Echocardiography 02/2014; 31(9). DOI:10.1111/echo.12540 · 1.26 Impact Factor
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    ABSTRACT: In this prospective study, we aimed to determine the protective antioxidant role of alpha-lipoic acid (ALA) on development of contrast-induced nephropathy (CIN) in diabetic patients undergoing coronary angiography. Seventy-eight diabetic patients undergoing coronary angiography were included. Thirty-nine patients were randomized to control group and 39 patients to ALA group. Both groups were hydrated on the day of angiography, and the ALA group had also received three doses of "Thioctacid 600 mg HR, MEDA Manufacturing GmbH" in pill form. Serum creatinine clearance, cystatin C, and urinary neutrophil gelatinase-associated lipocalin (NGAL) were studied before and after angiography. We defined CIN as either ≥25% or ≥0.5 mg/dL increase in serum creatinine at 48th hour after angiography. Baseline clinical characteristics were similar in both groups. Mehran risk score and creatinine clearance were comparable in control and therapy groups (5.59 ± 1.96 vs. 5.49 ± 1.73, p = 0.54 and 89 ± 21 vs. 96 ± 24, p = 0.13, respectively). The volumes of contrast media (median values of 80 mL vs. 75 mL) and hydration with saline (2862 ± 447 mL vs. 2637 ± 592 mL) were also similar (p > 0.05). The incidence of CIN was the same (8%) in both the groups. Alterations in serum creatinine, cystatin C, and urinary NGAL levels before and after the procedure were comparable between the ALA and control groups (group p-values were >0.05 in two-way repeated measures analysis of variance). We presented for the first time that ALA therapy added to hydration does not decrease the risk of CIN development in diabetic patients undergoing coronary angiography.
    Renal Failure 05/2013; DOI:10.3109/0886022X.2013.790298 · 0.94 Impact Factor
  • International Journal of Cardiology 03/2013; 163(3):S24. DOI:10.1016/S0167-5273(13)70061-5 · 6.18 Impact Factor
  • International Journal of Cardiology 03/2013; 163(3):S62. DOI:10.1016/S0167-5273(13)70158-X · 6.18 Impact Factor
  • Hellenic journal of cardiology: HJC = Hellēnikē kardiologikē epitheōrēsē 03/2013; 54(4):316-7. DOI:10.1016/S0167-5273(13)70007-X · 0.79 Impact Factor
  • International Journal of Cardiology 03/2013; 163(3):S15. DOI:10.1016/S0167-5273(13)70036-6 · 6.18 Impact Factor
  • Anadolu kardiyoloji dergisi: AKD = the Anatolian journal of cardiology 12/2012; 13(2). DOI:10.5152/akd.2013.044 · 0.72 Impact Factor
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    ABSTRACT: Fas/Fas ligand system contributes to the programmed cell death induced by myocardial ischemia. We investigated whether serum soluble Fas ligand (sFasL) level is independently related with the severity and extent of angiographically assessed coronary artery disease (CAD). We included 169 patients in this study. Two groups were formed based on the existence of a lesion on coronary angiography. First group included patients with normal coronary arteries (NCA; = 53). Patients with atherosclerotic lesions were included in the second group ( = 116). We used the coronary vessel score (the number of the coronary arteries with a lesion leading to ≥ 50% luminal obstruction) and the Azar score to determine the extent and the severity of CAD. Standard enzyme-linked immunosorbent assay kits were used to measure serum sFasL levels. The serum sFasL level was higher in patients with CAD than in patients with NCA (0.52 ± 0.23 mU/mL vs. 0.45 ± 0.18 mU/mL, = 0.023). The sFasL level correlated with Azar score ( = 0.231, = 0.003) and with coronary vessel score ( = 0.269, < 0.001). In the multivariate analysis, we found that age (beta: 0.188, = 0.008), gender (beta: 0.317, < 0.001), diabetes mellitus (DM; beta: 0.195, = 0.008), and sFasL level (beta: 0.209, = 0.003) were independently related with Azar score. When we used coronary vessel score as the dependent variable, we found that age ( = 0.020), gender ( < 0.001), DM ( = 0.006), and sFasL level ( = 0.001) were independent predictors. Serum sFasL level is associated with angiographically more severe CAD. Our findings suggest that sFasL level may be a biochemical surrogate of severe coronary atherosclerosis.
    International Journal of Angiology 03/2012; 21(1):29-34. DOI:10.1055/s-0032-1306418
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    ABSTRACT: We investigated the prognostic importance of plasma myeloperoxidase levels in patients with ST-elevation myocardial infarction (STEMI) at long-term follow-up, and we analyzed the correlations between plasma myeloperoxidase levels and other biochemical values.We evaluated 73 consecutive patients (56 men; mean age, 56 ±11 yr) diagnosed with acute STEMI and 46 age- and sex-matched healthy control participants. Patients were divided into 2 groups according to the median myeloperoxidase level (Group 1: plasma myeloperoxidase ≤68 ng/mL; and Group 2: plasma myeloperoxidase >68 ng/mL). Patients were monitored for the occurrence of major adverse cardiovascular events (MACE), which were defined as cardiac death; reinfarction; new hospital admission for angina; heart failure; and revascularization procedures.The mean follow-up period was 25 ± 16 months. Plasma myeloperoxidase levels were higher in STEMI patients than in control participants (82 ± 34 vs 20 ±12 ng/mL; P=0.001). Composite MACE occurred in 12 patients with high myeloperoxidase levels (33%) and in 4 patients with low myeloperoxidase levels (11%) (P=0.02). The incidences of nonfatal recurrent myocardial infarction and verified cardiac death were higher in the high-mye-loperoxidase group. In multivariate analysis, high plasma myeloperoxidase levels were independent predictors of MACE (odds ratio = 3.843; <95% confidence interval, 1.625-6.563; P=0.003).High plasma myeloperoxidase levels identify patients with a worse prognosis after acute STEMI at 2-year follow-up. Evaluation of plasma myeloperoxidase levels might be useful in determining patients at high risk of death and MACE who can benefit from further aggressive treatment and closer follow-up.
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2012; 39(4):500-6. DOI:10.1016/S0735-1097(10)61157-6 · 0.67 Impact Factor
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    ABSTRACT: The impact of dialysis type on the biomarkers that reflect the severity of cardiovascular diseases is not clearly known. We aimed to investigate the effect of dialysis type on biomarkers of cardiovascular diseases in patients with end-stage renal disease (ESRD). The study included 108 patients who had been on dialysis treatment (57 patients receiving hemodialysis, 51 patients receiving peritoneal dialysis) for ESRD for at least three months. Blood samples were collected just after the dialysis. Serum N-terminal prohormone of brain natriuretic peptide (NT-proBNP), high-sensitivity C-reactive protein (hs-CRP), cardiac troponin I (TnI), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and plasma fibrinogen levels were measured and compared between the two dialysis groups. The two dialysis groups were similar with respect to age and gender. The frequency of hypertension was significantly higher in patients receiving peritoneal dialysis. This group also had higher total cholesterol, HDL cholesterol, LDL cholesterol, and hemoglobin levels. Serum levels of NT-proBNP, hs-CRP, IL-6, and TNF-α, and plasma fibrinogen levels were similar in the two dialysis groups (p>0.05), but TnI was significantly higher in patients receiving peritoneal dialysis (p=0.04). Comparison of the patient subgroups based on the duration of dialysis (<12 months, 12-36 months, and >36 months) showed that longer dialysis duration was associated with significantly lower values of NT-proBNP, TNF-α, and hs-CRP (p<0.05). The dialysis type does not affect serum NT-proBNP, hs-CRP, IL-6, TNF-α, and plasma fibrinogen levels, but TnI level is higher in patients treated with peritoneal dialysis.
    Turk Kardiyoloji Dernegi arsivi: Turk Kardiyoloji Derneginin yayin organidir 09/2011; 39(6):456-62.

Publication Stats

171 Citations
84.71 Total Impact Points

Institutions

  • 2012–2015
    • Baskent University
      • Department of Cardiology
      Engüri, Ankara, Turkey
  • 2005–2012
    • Gazi University
      • Department of Cardiology
      Engüri, Ankara, Turkey
  • 2009
    • Erciyes Üniversitesi
      • Department of Cardiology
      Melikgazi, Kayseri, Turkey