The study demonstrates for the first time impaired peak cardiac performance and cardiac functional reserve in asymptomatic CKD patients. The evidence of myocardial dysfunction in the absence of comorbid cardiac disease and diabetes warrants further evaluation of current pathophysiological concepts of cardiovascular disease in CKD.
Although the relationship between protein-bound uremic toxins (PBUTs) and cardiac structure and cardiac mortality in chronic kidney disease (CKD) has been studied in the past, the association between cardiac dysfunction and PBUTs has not yet been studied. We therefore evaluated the association between impaired peak cardiac performance and the serum free and total concentrations of potentially cardiotoxic PBUTs. In a cross-sectional study of 56 male CKD patients (stages 2–5 (pre-dialysis)) who were asymptomatic with no known cardiac diseases or diabetes we measured peak cardiac power (CPOmax), aerobic exercise capacity (VO2max), and echocardiographic parameters of cardiac morphology and evaluated their association with PBUTs. The serum total and free concentrations of indoxyl sulfate (IXS), p-cresyl sulfate (PCS), p-cresyl glucuronide, indole acetic acid, and hippuric acid showed significant negative correlation with CPOmax and VO2max. IXS and PCS were independently associated with CPOmax and VO2max even after controlling for eGFR. No correlation between left ventricular mass index (LVMI) and PBUTs was seen. The present study for the first time has demonstrated the association between subclinical cardiac dysfunction in CKD and serum levels of a panel of PBUTs. Further studies are required to evaluate the mechanism of cardiotoxicity of the individual uremic toxins.
Background Impaired exercise capacity is a significant symptom of CKD and is associated with poor survival. Furthermore, there is a growing interest in applying exercise as a diagnostic tool or as therapy in CKD. However, an in-depth understanding of exercise physiology in CKD is still lacking.
Methods To evaluate the role of cardiac (central) and noncardiac (peripheral) determinants of exercise capacity in CKD, we conducted a cross-sectional study of 70 male CKD patients (stages 2-5) without diabetes or cardiac disease, 35 healthy controls, and 25 patients with heart failure. An integrated cardiopulmonary exercise test using a CO2 rebreathing technique was used to measure peak O2 consumption (VO2peak) and peak cardiac output simultaneously, and to calculate peak peripheral O2 extraction [C(a-v)O2], the peripheral determinant (the ability of exercising skeletal muscles to extract oxygen). We performed multiple regression analysis and used Bayesian information criteria (BIC) changes to quantitatively assess the individual contribution of central and peripheral factors.
Results Compared with healthy controls, in patients with CKD, the VO2peak was impaired proportionate to its severity. Peak cardiac output was the predominant determinant of VO2peak in healthy controls and patients with heart failure, whereas C(a-v)O2 played a more significant role in determining VO2peak in CKD (β=0.68, P<0.001) compared with cardiac output (β=0.63, P<0.001). In addition, the magnitude of BIC reduction was greater for C(a v)O2 compared with cardiac output (BIC, 298.72 versus 287.68) in CKD.
Conclusions In CKD, both peak cardiac output and peak C(a-v)O2 are independent predictors of VO2peak, and the more significant role played by peak C(a-v)O2 highlights the importance of noncardiac factors in determining exercise capacity in CKD.
Heart failure is a major cause of morbidity and mortality in chronic kidney disease (CKD). Rather than merely secondary to traditional vascular factors, CKD is also an independent risk factor for heart failure, termed uremic cardiomyopathy (UCM). Echocardiography commonly reveals structural left ventricular hypertrophy in CKD, without clarifying whether it is adaptive or maladaptive. Corresponding functional assessments have been mostly conducted at rest. To unravel the extents and mechanisms UCM, a next step involves the adoption of direct measurements of CKD-induced cardiac pumping incapacity at peak exercise. This could potentially lead to future novel interventions to ameliorate or reverse UCM.
Medication allergies are potentially important but usually poorly documented in patient medical records. Allergy awareness by clinical staff may be low in the haemodialysis population despite their regular attendance for treatment sessions. A cross-sectional study of 25 patients in a satellite unit was performed. All known allergies were not documented in 36% of patients despite the patients being known to the renal service for more than five years. 81% of allergies were medication allergies. The rest were due to topical agents. 57% (affecting 8 patients) of the medication allergies related to antibiotics (especially penicillin). Four patients had multiple antibiotic allergies. The nature and severity of these allergies was not well documented. This study demonstrates that despite being under long-term care there remains incomplete information, which is vital for optimal safe practice. Without such information, the potential for adverse events and anaphylaxis is significant in a population that is exposed to numerous pharmaceutical agents and are frequently prescribed antibiotics. Medication histories should be comprehensively re-evaluated regularly and prescribing should not occur unless the allergy box is completed.
Although all aspects of clinical work nowadays are modified by the pervading influence of evidence-based medicine (EBM) and multiplicative guidelines, not many clinicians realize that the underlying premise of EBM-driven guidelines is a particular strain of consequentialist ideology. Subservience to this ideology has transformed modern medical practice, but there is a real risk of distorting good medical practice, of belittling clinical judgement, of disempowering clinicians, and subjecting patients to skewed medical reality and treatment options. With so many heart failure (HF) guidelines issued by various august bodies, it is therefore timely to reappraise principles governing modern HF therapy with a fresh examination of the hierarchy of medical imperatives, the role of alternatives to consequentialism including deontological principles in HF therapy. In addition, other ideology worth re-examining, aside from EBM, are the principle of appropriate definition of HF underlying therapeutic goals and the principle of prioritizing objectives of HF therapy. Even within standard EBM, there are many questions to reconsider: about what types of evidence are admissible, different interpretations of available evidence, emphasizing patient-centered outcome measures instead of randomized controlled trials quantifiable therapeutic outcomes, how to prescribe drugs for prognostic versus symptomatic benefits, and how to deliver HF therapy based on pathophysiological features through mechanistic considerations and not just confined to randomized controlled trials or meta-analytical statistical imperatives. Through re-examination of these fundamental principles of HF therapy, it is hoped that clinicians will be empowered to manage HF patients more holistically and better deliver HF therapies in the best interest of each individual patient.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.