Yazar "Covic, Adrian" seçeneğine göre listele

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    Ambulatory blood pressure monitoring: from old concepts to novel insights
    (SPRINGER, 2012) Kanbay, Mehmet; Turkmen, Kultigin; Ecder, Tevfik; Covic, Adrian
    Ambulatory blood pressure monitoring (ABPM) is an out-of-office technique for the assessment of 24-h blood pressure measurements. ABPM is indicated to diagnose many conditions, including white-coat hypertension, resistant hypertension, episodic hypertension, nocturnal hypertension, autonomic dysfunction, hypotension secondary to excessive usage of antihypertensive medication, and masked hypertension. ABPM gives a better prediction of clinical outcomes in patients with hypertension and cardiovascular diseases when compared to office blood pressure measurements. Recently, several new indices have been introduced with the aim of predicting various clinical end-points in several patient populations. In this review, we aimed to determine the clinical utility of 24-h ABPM and its potential implications for the management of hypertension in patients with a high risk of cardiovascular mortality and morbidity, as well as various novel indices that can predict clinical end-points in different patient populations.
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    Electrocardiographic P-wave characteristics in patients with end-stage renal disease: P-index and interatrial block
    (SPRINGER, 2013) Solak, Yalcin; Gul, Enes Elvin; Kayrak, Mehmet; Atalay, Huseyin; Abdulhalikov, Turyan; Turk, Suleyman; Covic, Adrian
    P-wave parameters including P-wave dispersion (P (d)) have been examined in general population to predict development of atrial fibrillation (AF). But data on end-stage renal disease (ESRD) population are limited. P index (Pi) and interatrial block (IAB) as novel parameters may more accurately predict AF and have not been previously investigated in ESRD patients. We aimed to evaluate these novel ECG parameters in ESRD patients. Eighty-six HD, 47 CAPD, and 43 age- and gender-matched control subjects were enrolled in the study. P-wave duration was measured in all 12-leads of the surface ECG. The standard deviation of the P-wave duration across the 12 ECG leads was accepted as a Pi. P-wave duration above and equal to 110 ms was defined as IAB. All P-wave parameters were evaluated digitally by two observers. Pi was found to be significantly different among the groups in ANOVA. In post hoc analysis, P (i) was increased in HD group compared with the control group (p = 0.01). Also, P (i) tended to increase in CAPD group compared with controls (p = 0.06). The effect of ESRD on P (i) was independent of age, gender, and systolic blood pressure in univariate covariant analysis. The prevalence of IAB was 61, 55, and 32 % in patients with HD, CAPD, and controls, respectively (p = 0.001). P (d) was significantly higher in HD group compared with healthy controls. However, Pd values of CAPD patients did not show significant difference compared with controls. The present study demonstrated that IAB frequency and Pi were increased in patients with ESRD.
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    Microvascular disease and its role in the brain and cardiovascular system: a potential role for uric acid as a cardiorenal toxin
    (OXFORD UNIV PRESS, 2011) Kanbay, Mehmet; Sanchez-Lozada, Laura-Gabriela; Franco, Martha; Madero, Magdalena; Solak, Yalcin; Rodriguez-Iturbe, Bernardo; Covic, Adrian
    Arteriolosclerosis (microvascular disease) may have a key role not only in driving salt-sensitive hypertension but also in mediating the development of chronic kidney disease, vascular dementia, stroke and coronary heart disease. In this paper, we review the evidence that these latter conditions result from the altered autoregulation that occurs when arterioles become diseased. We also discuss the increasing evidence that dietary intake of sugars rich in fructose may be driving the development of microvascular disease as a consequence of raising intracellular uric acid. We hypothesize that the treatment of microvascular disease may require a multifaceted approach by utilizing agents which aim at blocking of the renin-angiotensin system, reducing oxidative stress, stimulating endothelial nitric oxide production and lowering uric acid levels. Paradoxically, agents that only stimulate nitric oxide, such as oestrogens, may increase the risk of poor outcomes if microvascular disease is not reversed.
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    Renal Anemia of Inflammation: The Name Is Self-Explanatory
    (KARGER, 2011) Yilmaz, Mahmut Ilker; Solak, Yalcin; Covic, Adrian; Goldsmith, David; Kanbay, Mehmet
    Background: Anemia is inevitable as chronic kidney disease (CKD) advances. With the advent of erythropoietin-stimulating agents (ESAs), considerable improvement has been achieved in the management of anemia. However, some patients show a reduced response to ESAs. Methods: Many factors affect the response to ESA treatment. CKD is now considered as an inflammatory disorder and this understanding led to the recognition of the central role of inflammation in ESA resistance. Inflammation is related to untoward outcomes, including atherosclerosis and anemia, in the CKD population. Furthermore, recognition of deleterious effects of proinflammatory markers at different levels of erythropoiesis led to a change in the name of 'anemia of chronic disease' to anemia of inflammation. Results: The discovery of hepcidin as the major controller of iron metabolism in anemia of inflammation answered many questions regarding the interaction of erythropoietin, iron and bone marrow. Hepcidin production in the liver is driven by three major factors: inflammation, iron overload and anemia/hypoxia. Hepcidin levels are increased in patients with CKD due to the interaction of many factors; a comprehensive understanding of these pathways is thus critical in the effort to alleviate anemia of inflammation and ESA resistance. Conclusion: In this review, we discussed the epidemiology, determinants and consequences of anemia of inflammation in CKD patients with special emphasis on the central role of hepcidin along with molecular pathways driving its production. Copyright (C) 2011 S. Karger AG, Basel
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    Sudden Cardiac Death in Patients with Chronic Kidney Disease: Prevention Is the sine qua non
    (KARGER, 2011) Kanbay, Mehmet; Solak, Yalcin; Covic, Adrian; Goldsmith, David
    Despite developments in the technology of dialysis procedures and improvements in the understanding of systemic derangements related to chronic kidney disease (CKD), cardiovascular disease is the major cause of death. Unfortunately, the leading subset of cardiovascular disease death is sudden cardiac death (SCD). To date much effort has been exerted to figure out the clues pointing to the risk of future development of SCD in patients with CKD. However, none of these factors satisfactorily detects a truly vulnerable dialysis patient. Thus, recently, it has been advocated that a combination of noninvasive risk assessment methods, carefully chosen to reflect the different aspects of the underlying pathology and changes in the myocardial substrate in CKD, could help to identify patients at high risk of SCD within the CKD. In this review, we aimed to summarize what is known about risk stratification of patients with CKD and appropriate prevention strategies with a special emphasis on recent developments and the use of complimentary tests perhaps as a risk prediction rule. Copyright (C) 2011 S. Karger AG, Basel
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    Uric Acid in Hypertension and Renal Disease: The Chicken or the Egg?
    (KARGER, 2010) Kanbay, Mehmet; Solak, Yalcin; Dogan, Ekrem; Lanaspa, Miguel A.; Covic, Adrian
    After uric acid was recognized as the causative factor in gout, increased prevalence of renal disease and hypertension in this patient population caught the attention of the medical community. Thus, it has been proposed that uric acid might have caused these disorders. However, uric acid suffered a long period of ignorance in which it was considered a metabolically inert substance. However, recent years has witnessed a resurrection of interest. Experimental studies showed an association between increased uric acid and renal arteriolar disease and hypertension. These preliminary results were supported with clinical studies. However, controversy regarding the precise pathophysiologic role of uric acid in inducing hypertension and renal disease remains to be elucidated. Despite being limited at this time, a few randomized intervention studies showed that even treatment of asymptomatic hyperuricemia was beneficial in terms of blood pressure regulation and kidney function. In this review, we focus on the pathophysiologic role of uric acid in the development and progression of renal disease and hypertension. We also discuss recent clinical evidence suggesting a causal role of uric acid in these disease states. Copyright (C) 2010 S. Karger AG, Basel