Intersection of cardiovascular disease and kidney disease: atrial fibrillation

Nonvalvular atrial fibrillation in patients undergoing chronic hemodialysis. Should dialysis patients with atrial fibrillation receive oral anticoagulation?

Chronic kidney disease (CKD) is an independent risk factor for presenting atrial fibrillation (AF), which conditions an increased risk already present in CKD of suffering a thromboembolic event. And this risk is even higher in the hemodialysis (HD) population. On the other hand, in CKD patients and even more so in HD patients, the probability of suffering serious bleeding is also higher. Therefore, there is no consensus on whether or not to anticoagulate this population. Taking as a model what is advised for the general population, the most common attitude among nephrologists has been to opt for anticoagulation, even though there is no randomized studies to support it. Classically, anticoagulation has been done with vitamin K antagonists, at high cost for our patients: severe bleeding events, vascular calcification, and progression of nephropathy, among other complications. With the emergence of direct-acting anticoagulants, a hopeful outlook was opened in the field of anticoagulation, as they were postulated as more effective and safer drugs than antivitamin K. However, in clinical practice, this has not been the case. In this paper we review various aspects of AF and its anticoagulant treatment in the HD population.

Association of circulating cardiac biomarkers with electrocardiographic abnormalities in chronic kidney disease

BACKGROUND

Among patients with chronic kidney disease (CKD), the circulating cardiac biomarkers soluble ST2 (SST2), galectin-3, growth differentiation factor-15 (GDF-15), N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin-T (hsTnT) possibly reflect pathophysiologic processes and are associated with clinical cardiovascular disease. Whether these biomarkers are associated with electrocardiographic findings is not known. The aim of this study was to test the association between serum cardiac biomarkers and the presence of electrocardiographic changes potentially indicative of subclinical myocardial disease in patients with CKD.

METHODS

We performed a cross-sectional analysis using 3048 participants from the Chronic Renal Insufficiency Cohort (CRIC) without atrial fibrillation, atrioventricular block, bundle branch block or a pacemaker at the baseline visit. Using logistic regression, we tested the association of each of the five cardiac biomarkers with baseline electrocardiogram (ECG) findings: PR interval >200 ms, QRS interval >100 ms and a prolonged QTc interval. Models were adjusted for demographic variables, measures of kidney function, prevalent cardiovascular disease and cardiovascular risk factors.

RESULTS

In adjusted models, hsTnT levels associated with prolonged PR {odds ratio [OR] 1.23 [95% confidence interval (CI) 1.08-1.40]}, QRS [OR 1.28 (95% CI 1.16-1.42)] and QTc [OR 1.94 (95% CI 1.50-2.51)] intervals. NT-proBNP levels were associated with prolonged QRS [OR 1.11 (95% CI 1.06-1.16)] and QTc [OR 1.82 (95% CI 1.58-2.10)] intervals. SST2, galectin-3 and GDF-15 were not significantly associated with any of the ECG parameters.

CONCLUSIONS

hsTnT and NT-proBNP were associated with ECG measures indicative of subclinical myocardial dysfunction. These results may support future research investigating the significance of myocardial ischemia and volume overload in the pathogenesis of dysfunctional myocardial conduction in CKD.

Does Atrial Fibrillation Increase the Risk of Developing End-stage Renal Disease in Patients with Chronic Kidney Disease?

Patients with atrial fibrillation (AF) have elevated risks of developing stroke, heart failure, and myocardial infarction. However, the impact of AF on the progression of chronic kidney disease (CKD) is uncertain. Our review objective is to investigate whether AF increases the risk of developing end-stage renal disease (ESRD) in patients with CKD. On 31 January 2019, a systemic search was performed on the MEDLINE database using the predefined search criteria. Limits included human participants and English-language publications. Studies that evaluated an association of AF and the risk of CKD progression to ESRD were selected. A total of 751 articles were identified. One prospective cohort study was included after screening abstracts from overall retrieved studies based on our inclusion/exclusion criteria, with a total of 3,091 CKD patients and a mean follow-up of 5.9 years. A total of 172 CKD patients developed AF, of which 43 patients later developed ESRD. Of 2,919 CKD patients with no incident AF, 581 patients progressed to ESRD. The rate of ESRD after the development of AF was 11.8/100 person-years compared with 3.4/100 person-years in CKD patients without AF. In conclusion, AF is an independent risk factor for developing ESRD in CKD patients, but more evidence is needed to support this result.

Role of direct oral anticoagulants in patients with kidney disease

The anticoagulation field is experiencing a renaissance that began with regulatory approval of the direct thrombin inhibitor dabigatran, a direct oral anticoagulant (DOAC), in 2010. The DOAC medication class has rapidly evolved to include the additional approval of 4 direct factor Xa inhibitors. Commensurately, DOAC use has increased and collectively account for the majority of new anticoagulant prescriptions. Despite exclusion of patients with moderate-to-severe kidney disease from most pivotal DOAC trials, DOACs are increasingly used in this setting. An advantage of DOACs is similar or improved antithrombotic efficacy with less bleeding risk when compared with traditional agents. Several post hoc analyses, retrospective studies, claims data studies, and meta-analyses suggest that these benefits extend to patients with kidney disease. However, the lack of randomized controlled trial data in specific kidney disease settings, with their unique pathophysiology, should be a call to action for the kidney community to systematically study these agents, especially because early data suggest that DOACs may pose less risk of anticoagulant-related nephropathy than do vitamin K antagonists. Most DOACs are renally cleared and are significantly protein bound in circulation; thus, the pharmacokinetics of these drugs are influenced by reduced renal function and proteinuria. DOACs are susceptible to altered metabolism by P-glycoprotein inhibitors and inducers, including drugs commonly used for the management of kidney disease comorbidities. We summarize the currently available literature on DOAC use in kidney disease and illustrate knowledge gaps that represent important opportunities for prospective investigation.

Chronic Kidney Disease is Associated with Intracranial Artery Stenosis Distribution in the Middle-Aged and Elderly Population

Aims: To investigate the association of chronic kidney disease (CKD) and intracranial artery stenosis (ICAS), as well as its effects on ICAS distribution in the middle-aged and elderly population.

Methods: Data from the China Hypertension Survey in Beijing was analyzed. Estimated glomerular filtration rate (eGFR) was used to evaluate CKD, and ICAS was assessed by transcranial doppler. Clinical and biochemical variables were compared between the ICAS group and the non-ICAS group, as well as in different vascular distribution groups. Univariable and multivariable logistic regression analyses were introduced to demonstrate the association between CKD and ICAS.

Results: A total of 3678 subjects were included in this study, with a mean age of 62 years old. Of which, 19.2% presented with decreased eGFR (eGFR < 60 ml/min/1.73 m²) and 17.4% for ICAS. The percentage of anterior circulation ICAS was 3.5 times than that of posterior circulation (10.9% vs. 3.1%). In multivariable regression analysis, eGFR < 45 ml/min/1.73 m² was independently associated with ICAS after correction for covariates, odds ratio (OR) = 1.69, 95% confidence interval (CI) (1.08, 2.65); in particular, this association had a preference for posterior circulation but not anterior circulation ICAS with OR = 2.29, 95% CI (1.28, 4.07) and OR = 1.44, 95%CI (0.89, 2.33), respectively.

Conclusion: Severe eGFR decline is associated with ICAS in the middle-aged and elderly population, and this correlation is more related to posterior circulation ICAS.

Anticoagulation in chronic kidney disease: from guidelines to clinical practice

BACKGROUND

Chronic kidney disease (CKD) is a major global public health problem, being closely connected to cardiovascular disease. CKD involves an elevated thromboembolic risk and requires anticoagulation, but the high rates of hemorrhage render it quite challenging.

HYPOTHESIS

There are no consensus recommendations regarding anticoagulation in CKD. Due to the currently limited data, clinicians need practical clues for monitoring and optimizing the treatment.

METHODS

Based on the available data, this review outlines the benefit-risk ratio of all types of anticoagulants in each stage of CKD and provides practical recommendations for accurate dosage adjustment, reversal of antithrombotic effect, and monitoring of renal function on a regular basis.

RESULTS

Evidence from randomized controlled trials supports the efficient and safe use of warfarin and direct oral anticoagulants (DOACs) in mild and moderate CKD. On the contrary, the data are poor and controversial for advanced stages. DOACs are preferred in CKD stages 1 to 3. In patients with stage 4 CKD, the choice of warfarin vs DOACs will take into consideration the pharmacokinetics of the drugs and patient characteristics. Warfarin remains the first-line treatment in end-stage renal disease, although in this case the decision to use or not to use anticoagulation is strictly individualized. Anticoagulation with heparins is safe in nondialysis-dependent CKD, but remains a challenge in the hemodialysis patients.

CONCLUSIONS

Although there is a need for cardiorenal consensus regarding anticoagulation in CKD, adequate selection of the anticoagulant type and careful monitoring are some extremely useful indications for overcoming management challenges.

New mineralocorticoid receptor antagonists: update on their use in chronic kidney disease and heart failure

Aldosterone is a mineralocorticoid hormone with a well-known effect on the renal tubule leading to water retention and potassium reabsorption. Other major effects of the hormone include the induction of proinflammatory activity that leads to progressive fibrotic damage of the target organs, heart and kidney. Blocking the aldosterone receptor therefore represents an important pharmacological strategy to avoid the clinical conditions deriving from heart failure (CHF) and chronic kidney disease (CKD). However, steroidal mineralocorticoid receptor antagonists (MRA) have a low safety profile, especially in CKD patients due to the high incidence of hyperkalemia. A new generation of nonsteroidal MRA has recently been developed to obtain a selective receptor block avoiding side-effects like hyperkalemia and thereby making the drugs suitable for administration to CKD patients. This review summarizes the results of published preclinical and clinical studies on the nonsteroidal MRA, apararenone esaxerenone and finerenone. The trials showed a better safety profile with maintained drug efficacy compared with steroidal MRA. For this reason, nonsteroidal MRA represent an interesting new therapeutic approach for the prevention of CHF and CKD progression. Some basic research findings also yielded interesting results in acute clinical settings such as myocardial infarction and acute kidney injury.

Rates of Cardiac Rhythm Abnormalities in Patients with CKD and Diabetes

BACKGROUND AND OBJECTIVES

Cardiac arrhythmias increase mortality and morbidity in CKD. We evaluated the rates of subclinical arrhythmias in a population with type 2 diabetes and patients with moderate to severe CKD who were not on dialysis.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

This is a prospective observational study, using continuous ambulatory cardiac monitors to determine the rate of atrial and ventricular arrhythmias, as well as conduction abnormalities in this group.

RESULTS

A total of 38 patients (34% women), with mean eGFR of 38±13 ml/min per 1.73 m², underwent ambulatory cardiac monitoring for 11.2±3.9 days. The overall mean rate of any cardiac arrhythmia was 88.8 (95% confidence interval [95% CI], 27.1 to 184.6) episodes per person-year (PY). A history of cardiovascular disease was associated with a higher rate of detected arrhythmia (rate ratio, 5.87; 95% CI, 1.37 to 25.21; P<0.001). The most common arrhythmia was atrial fibrillation, which was observed in two participants with known atrial fibrillation and was a new diagnosis in four patients (11%), none of whom experienced symptoms. Overall, atrial fibrillation episodes occurred at a rate of 37.6 (95% CI, 2.4 to 112.3) per PY. Conduction abnormalities were found in eight patients (21%), a rate of 26.5 (95% CI, 4.2 to 65.5) per PY. Rates of ventricular arrhythmias were low (14.5 per PY; 95% CI, 4.3 to 32.0) and driven by premature ventricular contractions.

CONCLUSIONS

Cardiac rhythm abnormalities are common in patients with diabetes with moderate to severe CKD not requiring dialysis. Rates of atrial fibrillation are high and episodes are asymptomatic. Future studies are needed to determine the role of screening and upstream therapy of cardiac arrhythmias in this group.

Contrast-induced nephropathy is associated with new-onset atrial fibrillation in acute coronary syndrome after cardiac catheterization: Systemic review and meta-analysis

INTRODUCTION

Contrast-induced nephropathy (CIN) is associated with increased cardiovascular morbidity and mortality in patients with acute coronary syndrome (ACS). Recent studies suggest that CIN is associated with new-onset atrial fibrillation (AF) in patients with acute coronary syndrome (ACS) who underwent catheterization. However, a systematic review and meta-analysis of the literature have not been done. We assessed the association between CIN in patients with ACS and new-onset AF by a systematic review of the literature and a meta-analysis.

HYPOTHESIS

CIN is associated with new-onset AF in patients with ACS.

METHODS

We comprehensively searched the databases of MEDLINE and EMBASE from inception to April 2018. Included studies were published cohort studies that compared new-onset AF after cardiac catheterization in ACS patient with CIN versus without CIN. Data from each study were combined using the random effects, generic inverse variance method of DerSimonian and Laird to calculate risk ratios and 95% confidence intervals.

RESULTS

Five studies from December 2009 to February 2018 were included in this meta-analysis involving 5,640 subjects with ACS (1,102 with CIN and 4,538 without CIN). Contrast-induced nephropathy significantly correlates with new-onset AF after cardiac catheterization (pooled risk ratio = 2.84, 95% confidence interval: 1.66-4.87, p < 0.001, I²  = 58%) CONCLUSIONS: Contrast-induced nephropathy is associated with new-onset AF threefold among patients with ACS after cardiac catheterization. Our study warranted further study to establish the causality between CIN and new-onset AF.

Epidemiology and Prognostic Importance of Atrial Fibrillation in Kidney Transplant Recipients: A Meta-Analysis

This meta-analysis was conducted with the aims to summarize all available evidence on (1) prevalence of pre-existing atrial fibrillation (AF) and/or incidence of AF following kidney transplantation; (2) the outcomes of kidney transplant recipients with AF; and (3) the trends of estimated incidence of AF following kidney transplantation over time. A literature search was conducted utilizing MEDLINE, EMBASE, and the Cochrane Database from inception through March 2018. We included studies that reported (1) prevalence of pre-existing AF or incidence of AF following kidney transplantation or (2) outcomes of kidney transplant recipients with AF. Effect estimates from the individual study were extracted and combined utilizing random-effect, generic inverse variance method of DerSimonian and Laird. The protocol for this meta-analysis is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42018086192). Eight cohort studies with 137,709 kidney transplant recipients were enrolled. Overall, the pooled estimated prevalence of pre-existing AF in patients undergoing kidney transplantation was 7.0% (95% CI: 5.6⁻8.8%) and pooled estimated incidence of AF following kidney transplantation was 4.9% (95% CI: 1.7⁻13.0%). Meta-regression analyses were performed and showed no significant correlations between year of study and either prevalence of pre-existing AF (p = 0.93) or post-operative AF after kidney transplantation (p = 0.16). The pooled odds ratios (OR) of mortality among kidney transplant recipients with AF was 1.86 (3 studies; 95% CI: 1.03⁻3.35). In addition, AF is also associated with death-censored allograft loss (2 studies; OR: 1.55, 95% CI: 1.02⁻2.35) and stroke (3 studies; OR: 2.54, 95% CI: 1.11⁻5.78) among kidney transplant recipients. Despite advances in medicine, incidence of AF following kidney transplant does not seem to decrease over time. In addition, there is a significant association of AF with increased mortality, allograft loss, and stroke after kidney transplantation.

Use of oral anticoagulants in patients with atrial fibrillation and renal dysfunction

Atrial fibrillation (AF) and chronic kidney disease (CKD) are increasingly prevalent in the general population and share common risk factors such as older age, hypertension and diabetes mellitus. The presence of CKD increases the risk of incident AF, and, likewise, AF increases the risk of CKD development and/or progression. Both conditions are associated with substantial thromboembolic risk, but patients with advanced CKD also exhibit a paradoxical increase in bleeding risk. In the landmark randomized clinical trials that compared non-vitamin K antagonist oral anticoagulants (NOACs) with warfarin for thromboprophylaxis in patients with AF, the efficacy and safety of NOACs in patients with mild-to-moderate CKD were similar to those in patients without CKD. Dose adjustment of NOACs as per the prescribing label is required in this population. Owing to limited trial data, evidence-based recommendations for the management of patients with AF and severe CKD or end-stage renal disease on dialysis are lacking. Observational cohort studies have reported conflicting results, and the management of these particularly vulnerable patients remains challenging and requires careful assessment of stroke and bleeding risk and, where appropriate, use of warfarin with good-quality anticoagulation control.

Wearable sensors: can they benefit patients with chronic kidney disease?

INTRODUCTION

This article ponders upon wearable medical measurement devices in relation to Chronic Kidney Disease (CKD) and its' associated comorbidities - and whether these might benefit CKD-patients. We aimed to map the intersection(s) of nephrology and wearable sensor technology to help technologists understand medical aspects, and clinicians to understand technological possibilities that are available (or soon will become so). Areas covered: A structured literature search on main comorbidities and complications CKD patients suffer from, was used to steer mini-reviews on wearable sensor technologies clustered around 3 themes being: Cardiovascular-related, diabetes-related and physical fitness/frailty. This review excludes wearable dialysis - although also strongly enabled by miniaturization - because that highly important theme deserves separate in-depth reviewing. Expert commentary: Continuous progress in integrated electronics miniaturization enormously lowered price, size, weight and energy consumption of electronic sensors, processing power, memory and wireless connectivity. These combined factors boost opportunities for wearable medical sensors. Such devices can be regarded as enablers for: Remote monitoring, influencing human behaviour (exercise, dietary), enhanced home care, remote consults, patient education and peer networks. However, to make wearable medical devices succeed, the challenge to fit them into health care structures will be dominant over the challenge to realize the bare technologies themselves.

Effect of Chronic Kidney Diseases on Mortality among Digoxin Users Treated for Non-Valvular Atrial Fibrillation: A Nationwide Register-Based Retrospective Cohort Study

PURPOSE

This study investigated the impact of chronic kidney disease on all-causes and cardiovascular mortality in patients with atrial fibrillation treated with digoxin.

METHODS

All patients with non-valvular atrial fibrillation and/or atrial flutter as hospitalization diagnosis from January 1, 1997 to December 31, 2012 were identified in Danish nationwide administrative registries. Cox proportional hazard model was used to compare the adjusted risk of all-causes and cardiovascular mortality among patients with and without chronic kidney disease and among patients with different chronic kidney disease stages within 180 days and 2 years from the first digoxin prescription.

RESULTS

We identified 37,981 patients receiving digoxin; 1884 patients had the diagnosis of chronic kidney disease. Cox regression analysis showed no statistically significant differences in all-causes (Hazard Ratio, HR 0.89; 95% confident interval, CI 0.78-1.03) and cardiovascular mortality (HR 0.88; 95%CI 0.74-1.05) among patients with and without chronic kidney disease within 180 days of follow-up period. No statistically significant differences was found using a 2 years follow-up period neither for all causes mortality (HR 0.90; 95%CI 0.79-1.03), nor for cardiovascular mortality (HR 0.87; 95%CI 0.74-1.02). No statistically significant differences was found comparing patients with and without estimated Glomerular Filtration Rate <30ml/min/1.73m2 and patients with different stages of chronic kidney disease, for all-causes and cardiovascular mortality within 180 days and 2 years from the first digoxin prescription.

CONCLUSIONS

This study suggest no direct effect of chronic kidney disease and chronic kidney disease stages on all-causes and cardiovascular mortality within both 180 days and 2 years from the first digoxin prescription in patients treatment-naïve with digoxin for non-valvular atrial fibrillation.

Atrial fibrillation and chronic kidney disease: focus on rivaroxaban

Renal insufficiency increases the risk of stroke and bleeding in atrial fibrillation patients. Although vitamin K antagonists reduce the risk of stroke in patients with moderate renal dysfunction, this observation is less clear in patients with renal impairment. Moreover, the risk of bleeding with vitamin K antagonists increases as renal function worsens. Maintaining international normalized ratio values within therapeutic targets is more difficult in patients with renal dysfunction, and those agents may cause warfarin-related nephropathy and vascular calcification. Rivaroxaban is the only nonvitamin K oral anticoagulant with a dose specifically tested in patients with moderate renal insufficiency. Rivaroxaban is effective for the prevention of stroke in atrial fibrillation patients with moderate renal dysfunction, with a lower risk of intracranial and fatal bleeding.

Postoperative atrial fibrillation in liver transplantation

Postoperative atrial fibrillation (POAF) is common after major surgeries and is associated with increased morbidity and mortality. POAF after liver transplantation (LT) has not been reported. This study was undertaken to investigate the incidence, impact, and risk factors of POAF in LT patients. After IRB approval, LT between January 2006 and August 2013 at our center were retrospectively reviewed. POAF that occurred within 30 days after LT was included. Patients with and without POAF were compared and independent risk factors were identified by logistic regression. Of 1387 adults LT patients, 102 (7.4%) developed POAF during the study period. POAF was associated with significantly increased mortality, graft failure, acute kidney injury and prolonged hospital stay. Independent risk factors included age, body weight, MELD score, presence of previous history of AF, the vasopressors use prior to LT and pulmonary artery diastolic pressure at the end of LT surgery (odds ratios 2.0-7.2, all p < 0.05). A risk index of POAF was developed and patients with the high-risk index had more than 60% chance of developing POAF. These findings may be used to stratify patients and to guide prophylaxis for POAF in the posttransplant period.