Chronic kidney disease (CKD) is strongly associated with cardiovascular disease (CVD); a graded inverse relationship between estimated glomerular filtration rate (eGFR) and cardiovascular event rates has emerged from large-scale observational studies. Chronic kidney disease is also associated with endothelial dysfunction (ED) although the precise relationship with GFR and the "threshold" at which ED begins are contentious. Abnormal endothelial function is certainly present in late-stage CKD but data in early-stage CKD appear confounded by disease states such as diabetes and hypertension which themselves promote ED. Thus, the direct effect of a reduction in GFR on endothelial function and, therefore, cardiovascular (CV) risk is far from completely established. In human studies, the precise duration of kidney impairment is seldom known and the onset of CVD often insidious, making it difficult to determine exactly when CVD first appears in the context of CKD. Kidney donors provide a near-ideal experimental model of CKD; subjects undergo an acute change from normal to modestly impaired renal function at the time of nephrectomy and lack the confounding co-morbidity that has made observational studies of CKD patients so challenging to interpret. By examining changes in endothelial function in living kidney donors before and after nephrectomy, useful insight might be gained into the pathophysiology of CVD in CKD and help determine whether targeting ED or the renal disease itself has the potential to reduce CV risk.
"In addition to the conventional CV risk factors (that is, hypertension, hypercholesterolaemia and smoking), other risk factors including activation of the renin-angiotensin-aldosterone system (RAAS), increased oxidative stress or inflammation, proteinuria and mineral bone disorder are also believed to be vital in contributing to the high CV burden in the CKD population [14,15]. Cardiovascular disease in CKD differs from that of the general population [14,15]. "
[Show abstract][Hide abstract] ABSTRACT: Background
Chronic kidney disease is associated with increased arterial stiffness even in the early stages and this is thought to be a key mediator in the pathophysiology of the increased cardiovascular risk associated with this condition. The use of low-dose spironolactone has previously been shown to improve arterial stiffness and reduce left ventricular mass safely in early-stage chronic kidney disease in the context of careful monitoring at a university hospital. However, the majority of patients with chronic kidney disease are managed by their general practitioners in the community. It is not known whether similar beneficial effects can be achieved safely using spironolactone in the primary care setting. The aim of this study is to determine whether low-dose spironolactone can safely lower arterial stiffness in patients with stage 3 chronic kidney disease in the primary care setting.
STOP-CKD is a multicentre, prospective, randomized, double-blind, placebo-controlled pilot trial of 240 adult patients with stage 3 chronic kidney disease recruited from up to 20 general practices in South Birmingham, England. Participants will be randomly allocated using a secured web-based computer randomization system to receive either spironolactone 25 mg once daily or a matching inactive placebo for 40 weeks, followed by a wash-out period of 6 weeks. Investigators, outcome assessors, data analysts and participants will all be blinded to the treatment allocation. The primary endpoint is improved arterial stiffness, as measured by carotid-femoral pulse wave velocity between baseline and 40 weeks. The secondary endpoints are incidence of hyperkalaemia, change in estimated glomerular filtration rate, change in urine albumin:creatinine ratio, change in brachial blood pressure, change in pulse waveform characteristics and overall tolerability of spironolactone. An additional quality control study, aiming to compare the laboratory serum potassium results of samples processed via two methods (utilizing routine transport or centrifugation on site before rapid transport to the laboratory) for 100 participants and a qualitative research study exploring patients’ and general practitioners’ attitudes to research and the use of spironolactone in chronic kidney disease in the community setting will be embedded in this pilot study.
Current Controlled Trials ISRCTN80658312.
[Show abstract][Hide abstract] ABSTRACT: Background:
Pneumoperitoneum during laparoscopic surgery is known to affect visceral blood flow and result in oxidative stress. Whether epidural anesthesia will effectively reduce visceral ischemia and oxidative stress by blocking the sympathetic nervous system (SNS) during laparoscopic surgery has not been proven.
Forty-five patients who were to undergo robot-assisted laparoscopic prostatectomy were randomly assigned to the combined general-epidural anesthesia group (group GE, n = 22) or to the general anesthesia group (group G, n = 23). Blood pressure, heart rate, and the balance between sympathetic and parasympathetic nervous system activity as measured by heart rate variability were recorded at 10 min after induction of anesthesia (T1), 60 (T2) and 120 (T3) min after intra-abdominal CO(2) insufflation, and 10 min after returning the patient to the supine position following CO(2) exsufflation (T4). Arterial blood gas analysis and blood sampling for measurements of nitrite (NO(2-)) and malondialdehyde (MDA) were performed at all time points.
Intraoperative mean blood pressure was significantly lower in group GE compared with group G. The low-frequency to high-frequency ratio was significantly increased after induction of pneumoperitoneum in group G but was unchanged in group GE. Plasma levels of nitrite decreased after pneumoperitoneum induction in group G while there was no change in group GE. A significant increase in MDA levels was seen in group G after pneumoperitoneum induction and were higher than group GE at T3 and T4. The 24-h urine output was higher in group GE than in group G on POD 1. The 24-h CrCl was higher in group GE on POD 1 but was not different between groups on POD 2.
Combined epidural and general anesthesia effectively blocks SNS stimulation during laparoscopic surgery and reduces NO inactivation and oxidative stress.
[Show abstract][Hide abstract] ABSTRACT: End stage renal disease is associated with a very high risk of premature cardiovascular death and morbidity. Early stage chronic kidney disease (CKD) is also associated with an increased frequency of cardiovascular events and is a common but poorly recognised and undertreated risk factor. Cardiovascular disease in CKD can be attributed to two distinct but overlapping pathological processes, namely atherosclerosis and arteriosclerosis. While the risk of athero-thrombotic events such as myocardial infarction is elevated, arteriosclerosis is the predominant pathophysiological process involving fibrosis and thickening of the medial arterial layer. This results in increased arterial stiffness causing left ventricular hypertrophy and fibrosis and the exposure of vulnerable vascular beds such as the brain and kidney to high pressure fluctuations causing small vessel disease. These pathophysiological features are manifest by a high risk of lethal arrhythmia, congestive heart failure, myocardial infarction and stroke. Recent work has highlighted the importance of aldosterone and disordered bone mineral metabolism.
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