Intra-Renal Hemodynamic Changes After Habitual Physical Activity in Patients with Chronic Kidney Disease

Background: Chronic Kidney Disease (CKD) is considered a silent epidemic with a continuously growing prevalence around the world. Due to uremia many functional and morphological abnormalities occur in almost all systems. Mostly affected, the cardiovascular system, leads to diminished cardiac function that affects patients’ functional capacity and physical activity levels, reducing survival and increasing all-cause mortality. Systematic exercise training ameliorates uremia induced body deficits and significantly improves the survival of CKD patients. Intradialytic exercise training has been recommended as a complementary therapeutic modality equally important to hemodialysis. Methods: The aim of this systematic review is to provide an update on recent advances in our understanding of how exercise training improves functionality of the cardiovascular system through the hemodynamic changes induced by habitual or intradialytic and/or home-based exercise training programs. Results: Systematic exercise training induces beneficial adaptive responses and influences many sensitive physiological biomarkers, such as oxidative stress biomarkers that are implicated in the development of atherosclerosis. Additionally, exercise training decreases the cardiovascular risk by improving the autonomic nervous system activity and the left ventricular function and by reducing nontraditional risk factors such as epicardial adipose tissue. It seems that all these central and peripheral adaptations to exercise training significantly contribute to improvements in functional capacity and exercise tolerance among CKD patients and result in the risk reduction of CKD-associated disorders. Conclusion: Exercise training could serve as a complimentary therapeutic strategy in CKD patients while health care providers should motivate patients to engage in any type of exercise training programs

Molecular bases of circadian rhythmicity in renal physiology and pathology

The physiological processes that maintain body homeostasis oscillate during the day. Diurnal changes characterize kidney functions, comprising regulation of hydro-electrolytic and acid-base balance, reabsorption of small solutes and hormone production. Renal physiology is characterized by 24-h periodicity and contributes to circadian variability of blood pressure levels, related as well to nychthemeral changes of sodium sensitivity, physical activity, vascular tone, autonomic function and neurotransmitter release from sympathetic innervations. The circadian rhythmicity of body physiology is driven by central and peripheral biological clockworks and entrained by the geophysical light/dark cycle. Chronodisruption, defined as the mismatch between environmental-social cues and physiological-behavioral patterns, causes internal desynchronization of periodic functions, leading to pathophysiological mechanisms underlying degenerative, immune related, metabolic and neoplastic diseases. In this review we will address the genetic, molecular and anatomical elements that hardwire circadian rhythmicity in renal physiology and subtend disarray of time-dependent changes in renal patholog

Prognostic and pathophysiological features of uraemic cardiomyopathy using cardiovascular magnetic resonance imaging

Premature cardiovascular (CV) death is the commonest cause of death in patients with end stage renal disease (ESRD), which includes those receiving or close to requiring renal replacement therapy. In ESRD patients, CV deaths are most commonly caused by cardiac arrhythmia and sudden cardiac death compared to the general population where myocardial ischaemia and infarction predominate. Higher CV disease burden is due to accumulation of “conventional” risk factors (e.g. hypertension, diabetes mellitus, smoking) and “novel” risk factors (e.g. oxidative stress, proteinuria, anaemia, inflammation) in ESRD patients. In addition, risk factors specific to patients with renal disease have been identified including alteration in left ventricular (LV) structure, called uraemic cardiomyopathy. These structural abnormalities are common in patients with ESRD (between 60-80% of subjects upon initiation of dialysis) and include left ventricular hypertrophy (LVH), systolic dysfunction (LVSD) and dilatation. These changes in LV structure confer adverse CV outcome in ESRD patients and have proven difficult to reverse. Detection of these abnormalities is usually performed using echocardiography, however this technique is inaccurate in ESRD patients due to significant alterations in LV shape and geometric assumptions made during calculation of myocardial mass. Cardiovascular MRI (CMR) negates these assumptions and is the most accurate, reproducible and reliable method of assessing LV dimensions independent of intravascular volume, particularly in patients with altered myocardial architecture. Furthermore, maximal left atrial volume can be measured using CMR. The principle aims of the studies presented in this thesis were to elucidate prognostic and pathophysiological features of uraemic cardiomyopathy using CMR. In a large study (n=246) of haemodialysis patients, the determinants of each LV abnormality of uraemic cardiomyopathy were identified from past clinical history, haemodialysis and blood parameters and other LV measurements. For LV changes, major determinants were clinical features associated with advanced renal disease, namely expansion of intravascular/ extracellular fluid compartment, abnormal bone mineral biochemistry and hypertension. Furthermore, presence of one LV abnormality was one of the strongest predictors of presence of another, perhaps indicating differing stages of uraemic cardiomyopathy development. In a subsequent prognostic study including these patients (n=446), presence of LVSD and LV dilatation on CMR were significantly associated with poorer all cause and CV mortality. Presence of LVH, which is by far the most common structural change, was associated with poorer cardiovascular survival only. In addition, presence of two or three abnormalities (commonly LVH with another abnormality) had a significantly poorer prognosis and independently predicted CV and all cause mortality. This has implications for therapeutic strategies which should aim to slow or reverse cardiac changes of ESRD and prevent progression from one cardiac abnormality to 2 or more. In a further study (n=201) investigating additional prognostic features of ESRD patients with LVH, maximal left atrial volume (LAV) was measured using the bi-plane area length method at end LV systole. Elevated LAV and presence of LVSD were significantly associated with poorer all cause survival and were independent predictors of death. The most likely causes of elevated LAV in ESRD patients are LV diastolic dysfunction and expanded extracellular compartment and may provide a target for therapeutic intervention. The electrophysiological features of uraemic cardiomyopathy were assessed using microvolt T wave alternans (MTWA) which is a novel, non-invasive method of measuring small variations in surface electrocardiogram (ECG) T wave morphology and thus ventricular repolarisation. This technique has been used to stratify other cohorts at elevated risk of sudden cardiac death (such as ischaemic and non ischaemic cardiomyopathy, hypertensive LVH). A study presented in this thesis, compared MTWA results between ESRD (n=200) and hypertensive patients with LVH on echocardiography (n=30). Abnormal MTWA result was significantly more common in ESRD patients compared to hypertensive patients with LVH. Furthermore, abnormal MTWA result was significantly associated with myocardial abnormalities of uraemic cardiomyopathy and a history of macrovascular atheromatous disease in ESRD patients. Despite preservation of LV function on CMR, the frequency of abnormal MTWA result in ESRD patients was similar to previous studies in subjects with heart failure. 31Phosphorus magnetic resonance spectroscopy is a novel, non-invasive technique of estimating cardiac energetic status and high energy phosphate (HEP) metabolism in a myocardial area of interest and has previously been used to assess patients with global myocardial disease (dilated cardiomyopathy, hypertensive LVH). High energy phosphate metabolism was compared between patients with ESRD (n=53) and hypertensive LVH (n=30) and despite similar LV mass between both groups, PCr: ATP (an indicator of HEP metabolism) was significantly reduced in ESRD patients. These findings are most likely due to cardiac interstitial fibrosis and the alteration of tissue composition within the area of interest, and changes in metabolic function within cardiomyocytes of uraemic hearts. Finally, a small study (n=50) investigated the effect of successful renal transplantation on LV mass measured by CMR. On comparison of patients who remained on the renal transplant waiting list, there was no significant difference in LV mass in patients who received a renal transplant. It is likely that previous echocardiography studies that demonstrated significant regression of LVH, measured improvement in fluid control rather that actual reduction in myocardial mass. Future studies investigating benefit of therapeutic intervention may require identification of individuals at higher CV risk and the results of studies presented in this thesis aim to provide information for selecting such ESRD patients. With these results in mind, further prospective studies will be able to carefully select groups of ESRD patients with differing left ventricular, left atrial, electrophysiological and biochemical properties to demonstrate survival benefit with interventional agents. In this way, future therapies for ESRD patients can be tailored to improve cardiovascular survival

Hypertension on Dialysis Patients: Influence Factor and Management

Background: Hypertension remains prevalent and challenging to manage in patients with chronic kidney disease, even with renal replacement therapy. This phenomenon arises from a variety of components that contribute to and create an intricate process of interaction, which can impact the regulation of blood pressure in patients undergoing dialysis. The main goal of this overview is to find the influence factor of blood pressure in dialysis patients and investigate ways to better control their blood pressure by incorporating these factors.Methods: The literature searches using online databases such as PubMed and Google Scholar. Results: After doing an online search, we found 32 articles were relevant to this review topic. Discussion: There are additional elements that contribute to hypertension in dialysis patients, including excessive volume, heightened arterial rigidity, stimulation of the renin-angiotensin-aldosterone system, sleep apnea, activation of the sympathetic nervous system, and the administration of recombinant erythropoietin.Conclusion: Enhanced comprehension of the numerous variables at issue can effectively enhance blood pressure regulation in this group of individuals

Prognostic Indicators of Cardiovascular Risk in Renal Disease

Although the annual mortality rate for end-stage renal disease (ESRD) is decreasing, likely due to an increase in kidney transplantation rate, the survival probability for ESRD patients from day one of dialysis has not changed, and is still poor with a 5-year survival rate of approximately 34%. This is contributed to by a high prevalence of cardiovascular disease, which is the leading cause of death in ESRD patients. In order to improve survival outcomes, patients at high risk of cardiovascular related mortality need to be identified. Heart rate variability (HRV), baroreceptor sensitivity, and baroreceptor reflex effectiveness index can be used to assess heart rate control and may predict cardiovascular mortality. This paper will discuss how HRV, baroreceptor sensitivity, and baroreceptor reflex effectiveness index are altered in renal disease and the utility of these indices as markers of cardiac risk in this patient population

Nursing Interventions for Intradialtyic Hypotension: Using Blood Volume Monitoring Guided Ultrafiltration

Background: Intradialytic hypotension is a potential complication experienced by patients with end-stage renal disease who receive hemodialysis. This complication occurs during the dialysis treatment in 15-30% of all treatments. The multiple comorbidities that exist in hemodialysis patients predispose them to recurrent intradialytic hypotension episodes. Recurrent intradialytic hypotensive episodes can result in negative short-term and long-term clinical consequences. Short-term consequences include complications such as ischemic events (e.g., heart attacks, strokes), clotting of patient dialysis access, or heart rhythm abnormalities. Long-term consequences include end-organ damage, increased cardiovascular morbidity, and a higher mortality rate. Problem Statement: Available nursing interventions used to treat intradialytic hypotension such as decreased dialysis fluid temperature, changes in the calcium and sodium concentrations in the dialysis fluid and oral medication have limited success. Another existing technological intervention called blood volume monitoring shows greater potential success but is currently underutilized. Purpose: The purpose of this literature review is to synthesize current literature on blood volume monitoring technology used to prevent intradialytic hypotension in hemodialysis patients. Methods: A literature review was conducted analyzing pertinent research articles published in the last ten years, in addition to seminal articles. Seventeen articles were retrieved and analyzed that met criteria. Results: Fourteen of the seventeen research studies reached a consensus on the successful use of blood volume monitoring to decrease intradialytic hypotension and the related symptoms. Conclusion: Results of the literature review support the use of blood volume monitoring technology as an effective nursing intervention to prevent intradialytic hypotension in hemodialysis patients

Optimal Blood Pressure Level and Best Measurement Procedure in Hemodialysis Patients

Hypertension occurs frequently among hemodialysis (HD) patients and can be due to many factors, such as salt intake, elevated sympathetic tone, and uremic toxins. It is responsible for the high cardiovascular risk associated with renal disease. Generally, in HD patients, while there is an elevation of systolic blood pressure (BP), diastolic BP seems to decrease, and the resultant effect is high pulse pressure, which can have a deleterious effect on the cardiovascular system. Although controversial, in the HD population the relationship between BP and risk of death seems to be U shaped, probably because of pre-existing cardiac disease in patients with the lowest BP. In chronic kidney disease, BP lower than 130/80 mmHg is recommended, but an appropriate target for BP in the HD population remains to be established. Moreover, there is no consensus regarding which routine peridialysis BP (pre- or post-dialysis BP, or both) can ensure the diagnosis of hypertension in this population. Ambulatory BP monitoring remains the gold standard to quantify the integrated BP load applied to the cardiovascular system. As well, home BP assessment could contribute to improve the definition of an optimal BP in the HD population. An ideal goal for post-dialysis systolic BP seems to be a value higher than 110 mmHg and lower than 150 mmHg. However, HD patients are generally old and often have cardiac complications, so a reasonable pre-dialysis target systolic BP could be 150 mmHg. It is prudent to suggest that an improvement in BP control is necessary in the HD population, first by slow and smooth removal of extracellular volume (dry weight) and thereafter by the use of appropriate antihypertensive medication

Role of osmolality in blood pressure stability after dialysis and ultrafiltration

Role of osmolality in blood pressure stability after dialysis and ultrafiltration. To clarify the mechanisms involved in the stability of blood pressure during ultrafiltration (UF) alone versus regular dialysis, this study systematically examined the importance of changes in serum potassium, osmolality, and plasma norepinephrine during several dialysis maneuvers. Six stable, normotensive chronic dialysis patients were subjected to a uniform 2 to 3% decrease in body weight during the 2 hours of each dialysis maneuver. Supine to upright mean blood pressure (MBP) decreased (90 to 75 mm Hg, P < 0.05), and three patients became symptomatic after weight loss during regular dialysis, but orthostatic blood pressure was stable (89 to 86 mm Hg, NS) and the patients were asymptomatic after UF and weight loss. Isokalemic regular dialysis did not afford hemodynamic stability, as orthostatic MBP declined (85 to 56 mm Hg, P < 0.02), and four of the patients again were symptomatic after standing. A continuous hypertonic mannitol (25%) infusion during the 2-hour dialysis, however, kept osmolality from decreasing and was associated with a stable orthostatic MBP (89 to 83 mm Hg, NS). A continuous infusion of isotonic mannitol (5%) given in a volume five times that of the hypertonic mannitol failed to prevent orthostatic hypotension (89 to 60 mm Hg, P < 0.005). Plasma norepinephrine concentrations were high in these patients and increased only modestly after weight loss. These results implicate constant plasma osmolality as a critical protective factor of blood pressure during UF and further demonstrate that changes in blood pressure may be dissociated from changes in both serum potassium and plasma norepinephrine concentration.Rôle de l'osmolalité dans la stabilité de la pression artérielle après dialyse et ultrafiltration. Afin de clarifier les mécanismes impliqués dans la stabilité de la pression artérielle au cours de l'ultrafiltration (UF) seule par comparaison avec la dialyse habituelle ce travail évalue systématiquement l'importance des modifications de la kaliémie, de l'osmolalité et de la norépinéphrine plasmatique au cours de plusieurs tactiques de dialyse. Six sujets stables, normotendus, en hémodialyse chronique ont subi une diminution de poids corporel de 2 à 3% au cours des 2 heures de chaque tactique de dialyse. La pression artérielle moyenne a diminué de la position couchée à la position debout (de 90 à 75 mm Hg, P < 0,05) et trois patients sont devenus symptomatiques après la perte de poids au cours de la dialyse habituelle. Par contre la pression artérielle orthostatique a été stable (89 à 86 mm Hg, NS) et les malades ont été asymptomatiques après UF. La dialyse habituelle isokaliémique n'a pas déterminé de stabilité hémodynamique, la pression artérielle moyenne orthostatique a diminué (85 à 56 mm Hg, P < 0,02) et quatre malades ont été à nouveau symptomatiques quand ils se sont levés. Cependant quand une perfusion continue de mannitol hypertonique (25%) pendant les deux heures de la dialyse a empêché la baisse de l'osmolalité la pression artérielle moyenne orthostatique a été stable (89 à 83 mm Hg, NS). Une perfusion continue de mannitol isotonique (5%) apportant un volume cinq fois celui du mannitol hypertonique n'a pas empêché l'hypotention orthostatique (89 à 60 mm Hg, P < 0,005). Les concentrations plasmatiques de norépinéphrine étaient élevées chez ces malades et n'ont que peu augmenté après la perte de poids. Ces résultats impliquent qu'une osmolalité plasmatique constante est un facteur protecteur critique pour la pression artérielle au cours de UF et ils démontrent, de plus, que les modifications de la pression artérielle peuvent être dissociées des modifications du potassium plasmatique et de la concentration de norépinéphrine

Perioperacijsko zbrinjavanje bolesnika s kroničnim bubrežnim zatajenjem

Any surgical procedure, ranging from general operation (the most common procedures is surgical creation of arteriovenous fistula and catheter for peritoneal dialysis placement) to open heart surgery, may be performed in patients with chronic renal failure treated conservatively or with dialysis without a significant increase in the perioperative mortality and morbidity in comparison to patients without renal disease. This is possibly only with good perioperative management of these patients and multidisciplinary collaboration of nephrologist, anesthesiologist, cardiologist, surgeon, primary care physician and nursing staff to recommend strategies for reducing cardiac and renal risk for the planned surgical procedures.Svaki kirurški postupak, od relativno jednostavnih (u ovih bolesnika najčešći su operacijsko stvaranje arteriovenske fistule i postavljanje katetera za peritonejsku dijalizu) do operacije na otvorenom srcu, može se u bolesnika s kroničnim bubrežnim zatajenjem koji se liječe konzervativno ili dijalizom učiniti bez značajnog porasta pobola i smrtnosti u odnosu na bolesnike bez bubrežne bolesti. Kako bi se mogli provesti planirani kirurški zahvati uz smanjenje srčanog i bubrežnog rizika za ove bolesnike neophodna je multidisciplinska suradnja nefrologa, anesteziologa, kardiologa, kirurga, liječnika opće medicine i sestrinskog tima za njegu bolesnika