Sudden cardiac death in chronic kidney disease: epidemiology and prevention

Annual cardiovascular mortality in patients with chronic kidney disease (CKD) is much higher than in the general population. The rate of sudden cardiac death increases as the stage of CKD increases and could be responsible for 60% of cardiac deaths in patients undergoing dialysis. In hemodialysis units treating patients with CKD, cardiac arrest occurs at a rate of seven arrests per 100,000 hemodialysis sessions. Important risk factors for sudden cardiac death in patients with CKD include hospitalization within the past 30 days, a drop of 30 mmHg in systolic blood pressure during hemodialysis, duration of life on hemodialysis, time since the previous dialysis session, and the presence of concomitant diabetes mellitus. As a result of the adverse cardiomyopathic and vasculopathic milieu in CKD, the occurrence of arrhythmias, conduction abnormalities, and sudden cardiac death could be exacerbated by electrolyte shifts, divalent ion abnormalities, diabetes, sympathetic overactivity, in addition to inflammation and perhaps iron deposition. Impaired baroreflex effectiveness and sensitivity, as well as obstructive sleep apnea, might also contribute to the risk of sudden death in CKD. The likelihood of survival following cardiac arrest is very low in dialysis patients. Primary and secondary prevention of cardiac arrest could reduce cardiovascular mortality in patients with CKD. Cardioverter-defibrillator implantation decreases the risk of sudden death in patients with CKD. The decision to implant a cardioverter-defibrillator should be influenced by the patient's age and stage of CKD.     

A Personalized Approach to Chronic Kidney Disease and Cardiovascular Disease: JACC Review Topic of the Week

Cardiovascular disease is the most common cause of death in patients with end-stage renal disease (ESRD). The initiation of dialysis for treatment of ESRD exacerbates chronic electrolyte and hemodynamic perturbations. Rapid large shifts in effective intravascular volume and electrolyte concentrations ultimately lead to subendocardial ischemia, increased left ventricular wall mass, and diastolic dysfunction, and can precipitate serious arrhythmias through a complex pathophysiological process. These factors, unique to advanced kidney disease and its treatment, increase the overall incidence of acute coronary syndrome and sudden cardiac death. To date, risk prediction models largely fail to incorporate the observed cardiovascular mortality in the CKD population; however, multimodality imaging may provide an additional prognostication and risk stratification. This comprehensive review discusses the cardiovascular risks associated with hemodialysis, and explores the pathophysiology and the novel utilization of multimodality imaging in CKD to promote a personalized approach for these patients with implications for future research.     

Sudden death secondary to cardiac arrhythmias: mechanisms and treatment strategies

PURPOSE OF REVIEW: This article reviews mechanisms and available therapeutic options for arrhythmias leading to sudden cardiac death in patients with coronary artery disease. RECENT FINDINGS: Intensive efforts have led to a better understanding of the pathophysiology and various treatments of sudden cardiac death. Antiarrhythmic medications have not demonstrated a survival benefit. Beta-adrenergic blocking agents have been revalidated in recent studies to improve survival and reduce risk of sudden cardiac death in patients with myocardial infarction. Angiotensin-converting enzyme inhibitors and aldosterone antagonists should also be used in these patients. Data from randomized trials demonstrate significant survival benefit with an implantable cardioverter-defibrillator and indications have expanded. Patients with established ischemic cardiomyopathy do not require electrophysiologic studies for induction of tachyarrhythmias based on these trials. One recent trial did not demonstrate mortality reduction with implantable defibrillators in patients with recent myocardial infarction. Devices may not provide survival benefit in patients with advanced New York Heart Association class IV heart failure. SUMMARY: The incidence of arrhythmia-related sudden death in the general population remains relatively high. Better risk stratification tools are needed to identify high-risk patients in the general population and in those with known coronary disease and to exclude low-risk patients.     

Dialysis patients and cardiovascular problems: Can technology help solve the complex equation?

Patients with end-stage kidney disease undergoing chronic hemodialysis (HD) present higher mortality rates compared with the general population. Once patients are on HD, the risk of cardiovascular death is approximately 30 times higher than in the general population and remains 10-20 times higher after stratification for age, gender, and the presence of diabetes. About half the deaths of patients on dialysis are attributed to cardiovascular causes including coronary heart disease, cerebrovascular disease, peripheral vascular disease, and heart failure. The cardiovascular burden of the HD patient arises from three different sources: risks inherent to the patient and the uremic syndrome, traditional risk factors, and risk factors related to the dialysis therapy. Based on these considerations and the fact that several aspects of the dialysis procedure can either add to the cardiovascular burden or modify the existing burden, new technologies should be directed towards the approach of a potential 'cardioprotective dialysis therapy'; such an approach may be facilitated by the application of new techniques and advanced dialysis machines. Created to make dialysis easy and safe, new machines feature several options that make patient monitoring and online hemodiafiltration therapy routine procedures. These and other features will possibly make dialysis better tolerated and more efficient in protecting patients from undesirable or potentially fatal cardiovascular events.     

Voie radiale et insuffisance rénale

Patients with chronic kidney disease have a high cardiovascular risk and mortality. This problem is growing because of the aging of the population and prevalence of diabetes. Transradial approach is traditionally prohibited due to the injury that catheterization induces on this artery that could possibly influence its suitability as an arteriovenous fistula. Paradoxically, the increased risk of major vascular complications with femoral access leads to transgress this rule. Indeed, transradial approach by reducing dramatically the rate of vascular bleeding complications leads to a significant reduction of adverse events and mortality, especially in the high cardiovascular risk sub-group. In patients with chronic kidney disease, choice of vascular access site should compare the potentially fatal risk of vascular complications with the one of traumatizing the artery needed to create a distal hemodialysis access site. Thus, chronic renal insufficiency even on hemodialysis should not be an absolute contraindication to radial approach, which could be used individually by a skilled team and in a mini-invasive spirit. A large randomised study comparing radial and femoral access in this population is needed.     

Chronic kidney disease and cardiovascular risk

Chronic kidney disease (CKD) is a global public health concern, and there is emerging a strong relationship between CKD and increased cardiovascular disease (CVD) risk. CKD in the presence of other co-morbidities such as type 2 diabetes mellitus (T2DM) and hypertension (HTN) can lead to early progression to end-stage renal disease (ESRD/stage V CKD) and confer a greater risk for CVD morbidity and mortality. CVD events are the leading cause of premature death in patients with CKD, even before their progression to ESRD, with the rate of CVD progression being twice as common compared with the general population. The higher mortality from CVD persists even after adjusting for most of the traditional risk factors, suggesting the possible contributions of uremia-related, nontraditional risk factors. This has led to the current understanding that the pathophysiology of CVD in CKD involves a complex interplay of both the traditional as well as nontraditional, uremia-related risk factors. This review will elaborate on the pathophysiology of CVD in CKD and will discuss the role of microalbuminuria (MAU)-proteinuria as a potential diagnostic and prognostic tool for CVD in CKD risk assessment.     

Prevention of heart failure in the elderly: when, where and how to begin?

Significant growth in the elderly population (age?≥?65?years) with heart failure (HF) has taken place in developed countries and is occurring in most developing countries. Projections from population studies in the United States, Europe and other developed countries suggest that this trend will very likely continue and tax healthcare systems worldwide. Prevention of HF in the elderly should be a healthcare priority. Preventive strategies are urgently needed to combat the rising burden of HF and related complications in elderly men and women of tomorrow. The strategies should address the aging continuum and the cumulative impact of lifelong exposure to cardiovascular (CV) risk factors and consider the associated pathobiology and pathophysiology of aging for optimal impact. Besides implementation of conventional primary and secondary prevention measures in young and older adults, more emphasis should be placed on education about the role of exposure to adverse CV risk factors from early childhood in the march to HF. More research is also needed to identify optimal HF therapies for different aging subgroups ranging from young adults to the elderly and very old based on understanding of pathobiology and pathophysiology.     

Prognostic Study of Cardiac Events in Japanese High Risk Hemodialysis Patients Using 123I‐BMIPP‐SPECT: B‐SAFE Study Design

Cardiovascular disease is the leading cause of morbidity and mortality in patients undergoing hemodialysis. Such patients frequently develop complications such as asymptomatic coronary artery disease (CAD). Accordingly, CAD must ideally be diagnosed at an early stage to improve prognosis. Although myocardial perfusion single photon emission computed tomography (SPECT) is valuable for diagnosing CAD, the stress test is not always applicable to patients on hemodialysis. Thus, we proposed a multicenter, prospective cohort study called “B‐SAFE” to investigate the applicability of resting ¹²³I‐labeled beta‐methyl‐iodophenylpentadecanoic acid (¹²³I‐BMIPP)‐SPECT will be used to diagnose cardiac disease and evaluate the prognosis of hemodialysis patients by imaging myocardial fatty acid metabolism. B‐SAFE began enrolling patients from June 2006 at 48 facilities. We performed ¹²³I‐BMIPP‐SPECT on 702 hemodialysis patients with risk factors for CAD until 30 November 2007 and plan to follow up for three years. The primary endpoints will be cardiac death and sudden death. This study should end in 2010.     

Epidemiology of sudden cardiac death in Spain]

Sudden cardiac death is a remarkable public health problem though its incidence in Spain is lower than in other industrialised countries. Approximately 12% of all natural deaths occur suddenly, and 88% of them are of cardiac origin. This is the form of death in more than 50% of coronary heart disease patients. Moreover, it is the first symptom in 19-26% of cases. This close relationship with coronary heart disease results in cardiovascular risk factors being also risk factors for sudden death. Several factors, such as physical activity or certain drugs may act as sudden death triggers. The more effective strategy addressed to sudden cardiac death prevention includes identification high-risk subgroups of patients (i.e. patients with previous coronary heart disease, heart failure, out-of-hospital sudden death survivors and patients who developed a ventricular fibrillation or tachycardia after a myocardial infarction) and development of efficacious therapeutic interventions. Given that most sudden death are related to coronary heart disease, those primary preventive measures directed to reduce the coronary heart disease incidence rates will also prevent sudden cardiac deaths in population. Finally, community programs directed to reduce the time to reach cardiac emergencies by trained personnel, and to train general population in cardio-respiratory reanimation have shown to be efficacious owing to the fact that most sudden cardiac deaths occur out of hospitals.     

Cardiovascular complications in children with chronic kidney disease

The lifespan of children with advanced chronic kidney disease (CKD) remains low compared with the general pediatric population. As in adults with CKD, cardiovascular disease accounts for the majority of deaths in children with CKD, as these patients have a high prevalence of traditional and uremia-related risk factors for cardiovascular disease. The cardiovascular adaptations that precipitate these terminal events begin in predialysis CKD. Initially, these alterations increase left ventricular performance and vascular function to maintain hemodynamic homeostasis. However, these modifications are unable to sustain cardiovascular function in the long term and ultimately lead to left ventricular failure, impaired cardiorespiratory fitness and even sudden death. In this Review, we provide an update on the prevalence of the risk factors associated with cardiovascular disease in pediatric patients with CKD, the cardiac and vascular adaptations that occur in these patients and the management of cardiovascular risk in this population.     

Genomics,heart failure and sudden cardiac death

Sudden cardiac death (SCD) is among the most common causes of death in developed countries throughout the world. Despite decreased overall cardiac mortality, SCD rates appear to be increasing in concert with escalating global prevalence of coronary disease and heart failure, the two major conditions predisposing to SCD. This unfavorable trend is a consequence of our inability to identify those who will die suddenly from lethal ventricular arrhythmias and to develop effective therapies for all populations at risk. The known risk factors for SCD lack the predictive power needed to generate preventive strategies for the large number of fatal arrhythmic events that occur among lower-risk subsets of the population. Even among recognized high-risk subsets, prediction of SCD remains challenging. With the exception of the implantable cardioverter defibrillator (ICD) there are few effective strategies for the prevention and treatment of SCD. This article discusses the prospect of genomic science as an approach to the identification of patients at high-risk for SCD. While the final common pathway for SCD is malignant ventricular arrhythmias, there are many potential contributors, pathways, and mechanisms by which common genetic variants (polymorphisms) could affect initiation and propagation of life-threatening cardiac arrhythmias. Recent advances in genomic medicine now provide us with novel approaches to both identify candidate genes/pathways and relatively common polymorphisms which may predispose patients to increased risk for SCD. Improved understanding of the relationship between common polymorphisms and SCD will not only improve risk stratification such that ICDs can be targeted to those patients most likely to benefit from them but also provide new insight into the pathophysiology of SCD.     

Assessment and management of atherosclerosis in the athletic patient

Many patients and physicians correctly associate physical activity with reduced cardiovascular morbidity and mortality. Vigorous physical exertion is paradoxically associated with a transient increase in the risk of cardiovascular events and sudden cardiac death. This review extrapolates data from the general population to the management of athletes with symptoms suspicious for coronary artery disease or with prior cardiac events. A history to elicit an athlete's concerns and symptoms combined with a physical examination should guide the decision for preparticipation exercise testing for athletes without prior cardiac events. Athletes with established coronary artery disease should receive aggressive secondary prevention regimens, with special attention to adverse effects that may be unique to this group. There may be benefit in taking time away from competitive athletics to allow for stabilization of coronary artery disease with cholesterol-lowering therapy and, therefore, reduction of future risk. Exercise testing is important for defining risk before the return to participation for athletes who have sustained a cardiac event. Many athletes will ultimately be able to return to full participation provided they have received aggressive therapy and understand the residual risk associated with vigorous physical exertion in the setting of coronary artery disease.     

End-Stage Renal Disease And Limb Salvage

The prevalence of peripheral arterial disease and both traditional and nontraditional vascular risk factors are more common in patients with end-stage renal disease who are undergoing hemodialysis than the general population. Patients undergoing hemodialysis may also be at risk for peripheral arterial disease via nonvascular risk factors and the hemodialysis treatment itself. Unfortunately, because peripheral arterial disease and its risk factors in hemodialysis patients have not been thoroughly ascertained, evaluation of potential treatments has been limited. Given the high potential of morbidity and impaired quality-of-life related to peripheral arterial disease in patients with end-stage renal disease, additional studies are needed to evaluate both quality of life and potential screening for peripheral arterial disease, its risk factors, and treatments to identify areas for improvement in this vulnerable population.     

Can we predict the occurrence of atrial fibrillation?

Atrial fibrillation (AF) is a complex disease with increasing prevalence in an aging population and longer survival with cardiovascular diseases. Whereas most clinical efforts have been aimed at predicting risk of AF sequelae such as stroke and heart failure, little is known on primary prevention. AF risk assessment is complicated by the existence of distinct subtypes of AF, such as lone AF or postoperative AF, in contrast to common AF in the elderly. Due to its often intermittent nature, diagnosing AF can be a challenge. Risk prediction becomes reasonable when specific interventions arise. Due to our limited understanding of AF pathophysiology and substantial lack of specific preventive strategies in the population, modification of the general cardiovascular risk profile has largely remained the only option. Initial attempts at combining established risk factors for AF such as age, sex, hypertension, body mass index, electrocardiographic characteristics, and cardiovascular disease in a risk-prediction instrument have produced a robust algorithm. However, known risk factors only explain a fraction of the population-attributable risk of AF, and the search for novel risk indicators is ongoing. More efficient monitoring for electrocardiographic precursors of AF and the field of genomics are evolving areas of AF risk factor research. A better understanding of the underlying substrate of AF will provide targets for prevention. In the future, clinical trials will be needed to establish risk categories, interventions, and their efficacy. Despite a relevant public-health impact, knowledge on risk prediction and primary prevention of AF is still limited today. There are no conflicts of interest to disclose.     

Efficacy of Coronary Artery Screening Tests and Intervention in Hemodialysis Patients

Although cardiovascular disease (CVD) is an important cause of death in patients on hemodialysis, evidence of a beneficial effect of percutaneous intervention (PCI) on stable heart disease is scarce. We investigated the cardiovascular outcomes of hemodialysis patients under our policy of encouraging coronary artery screening tests to the extent possible. A total of 147 hemodialysis patients have been treated in our clinic so far. In 98 of them, coronary artery screening tests were performed, three in unstable and 95 in asymptomatic patients. Significant coronary artery stenosis was detected in 29 at the first tests and in 11 during subsequent tests (40/98, 40.8%), and PCI or coronary artery bypass grafting (CABG) was performed. Multiple PCIs were needed in 21 patients. In the other 49 patients, coronary artery screening tests were not undertaken based on the nephrologist's decision or patient refusal. At the end of the study, 73 (74.5%) patients with tests, and 14 (28.6%) without tests were still outpatients (P < 0.01). Of 40 patients transferred to other hospitals for medical reasons or who died before transfer, there was cerebrovascular accident in eight, malignancy in six, congestive heart failure without CVD in four, infection in three, sudden cardiac death in one, and others 18. No patient with tests died of CVD and the only patient who died of sudden cardiac death probably due to myocardial infarction was a patient who had declined the screening tests. Coronary artery screening tests, intervention and subsequent periodic tests for asymptomatic hemodialysis patients can reduce the occurrence of cardiovascular events in this population.     

Cardiometabolic Effects of Glucagon-Like Peptide-1 Agonists

Cardiovascular disease is the leading cause of death among adults in the USA. Both type 1 (T1DM) and type 2 diabetes mellitus (T2DM) are known risk factors for cardiovascular disease. Despite the development of numerous effective anti-glycemic therapies, we have been unable to completely mitigate cardiovascular risk with glucose lowering alone, and prevention of cardiovascular disease in patients with diabetes is primarily achieved with the use of medications that address other risk factors such as anti-hypertensives or statins. Glucagon-like peptide-1 (GLP-1) is a key hormone in the pathophysiology of diabetes. GLP-1 agonists have been recently approved for the treatment of T2DM as well as for chronic weight management. In this review, we aim to explore the effects of GLP-1 agonists on cardiovascular health with a focus on cardiometabolic variables and cardiac function.     

Le risque cardiovasculaire au cours du lupus systémique

Multiple factors contribute to the increased cardiovascular risk observed in patients with systemic lupus erythematosus (SLE). Among these are the so-called classical cardiovascular risk factors, the disease itself through its activity, treatments, and complications, and the thrombotic risk due to antiphospholipid antibodies (aPL). Observational studies suggest that most classical cardiovascular risk factors are observed more frequently in SLE patients than in the general population, and that these are insufficient to explain the increased cardiovascular risk observed in most studies. Given this high risk, adequate management of cardiovascular risk factors should be recommended in SLE patients. Paradoxically, the benefit due to the anti-inflammatory properties of treatments such as corticosteroids may exceed, in certain cases, their pro-atherogenic effect. Importantly, the tools that were developed for the estimation of cardiovascular risk at the individual level among the general population cannot be used reliably in SLE patients, as these tools appear to underestimate the true cardiovascular risk. The adequate indications and targets of cardiovascular treatments are therefore not fully known in SLE. A better understanding of the determinants of the cardiovascular risk in SLE will allow the identification and more tailored management of these high-risk patients.     

Knowledge of heart disease and stroke among cardiology inpatients and outpatients in a Canadian inner-city urban hospital

BACKGROUND:

Heart disease and stroke are leading causes of death in North America. Nevertheless, in 2003, the Heart and Stroke Foundation of Canada reported that nearly two-thirds of Canadians have misconceptions regarding heart disease and stroke, echoing the results of similar American studies. Good knowledge of these conditions is imperative for cardiac patients who are at greater risk than the general population and should, therefore, be better educated. The present study evaluated the awareness of heart disease and stroke among cardiac patients to assess the efficacy of current education efforts.

METHODS:

Two hundred fifty-one cardiac inpatients and outpatients at St Michael’s Hospital (Toronto, Ontario) were surveyed in July and August 2004. An unaided questionnaire assessed respondents’ knowledge of cardiovascular risk factors, symptoms of heart attack and stroke, and actions in the event of cardiovascular emergency. Demographic data and relevant medical history were also obtained.

RESULTS:

Cardiac patients demonstrated relatively adequate knowledge of heart attack warning symptoms. These patients also demonstrated adequate awareness of proper actions during cardiovascular emergencies. However, respondents were not aware of the most important risk factors for cardiovascular disease. Knowledge of stroke symptoms was also extremely poor. Socioeconomic status, and personal history of heart attack and stroke were positively correlated with good knowledge.

CONCLUSIONS:

Future patient education efforts should address the awareness of the important cardiovascular risk factors and knowledge of cardiovascular warning symptoms (especially for stroke), as well as inform patients of appropriate actions during a cardiovascular emergency. Emphasis should be placed on primary and secondary prevention, and interventions should be directed toward low-income cardiac patients.     

The role of preventive cardiology in systemic lupus erythematosus

With improved therapeutic advances in the care of systemic lupus erythematosus patients, cardiovascular disease has emerged as a leading cause of death. Premature atherosclerosis in lupus patients is probably an interaction between traditional cardiovascular risk factors, inflammatory factors, and factors related to lupus itself. Despite knowledge of this accelerated cardiac risk, evaluation of traditional risk factors has been sub-par. We propose that lupus patients be evaluated by preventive cardiologists and have access to their expertise and resources. In addition to nephrologists and dermatologists, preventive cardiologists should be an integral part of the care of patients with lupus.