Cardiac resynchronization therapy in CKD: a systematic review

Heart failure with reduced ejection fraction and chronic kidney disease: a focus on therapies and interventions

In heart failure with reduced ejection fraction (HFrEF), the presence of concomitant chronic kidney disease (CKD) predicts poorer cardiovascular outcomes, more aggravated heart failure (HF) status, and higher mortality. Physicians might be reluctant to initiate life-saving anti-HF medications out of fear of worsening renal function and a higher incidence of adverse events. Moreover, international guidelines do not give clear recommendations on managing this subgroup of patients as well as advanced CKD was always an exclusion criterion in most major HF trials. Nevertheless, in this review, we will highlight several recent clinical trials and post-hoc analyses of major trials that showed the safety and efficacy of the different therapies in HFrEF patients with CKD, besides several small-scale cohorts that tested guideline-directed medical therapies in End Stage Kidney Disease (ESKD). Regarding interventions in this subgroup of patients, we will provide up-to-date data on implantable cardioverter defibrillators, cardiac resynchronization therapy, and coronary revascularization, in addition to mitral valve transcatheter edge-to-edge repair and implantable pulmonary artery pressure sensors.

Management of patients with heart failure and chronic kidney disease

Chronic kidney disease (CKD) and heart failure are often co-existing conditions due to a shared pathophysiological process involving neurohormonal activation and hemodynamic maladaptation. A wide range of pharmaceutical and interventional tools are available to patients with CKD, consisting of traditional ones with decades of experience and newer emerging therapies that are rapidly reshaping the landscape of medical care for this population. Management of patients with heart failure and CKD requires a stepwise approach based on renal function and the clinical phenotype of heart failure. This is often challenging due to altered drug pharmacokinetics interactions with various degrees of kidney function and frequent adverse effects from the therapy that lead to poor patient tolerance. Despite a great body of clinical evidence and guidelines that have offered various treatment options for patients with heart failure and CKD, respectively, patients with CKD are still underrepresented in heart failure clinical trials, especially for those with advanced CKD and end-stage renal disease (ESRD). Future studies are needed to better understand the generalizability of these therapeutic options among heart failures with different stages of CKD.

Cardiac Devices and Kidney Disease

A growing variety of cardiac devices are available to monitor or support cardiovascular function. The entwined nature of cardiovascular disease and kidney disease makes the relationship of these devices with kidney disease a multifaceted question relating to the use of these devices in individuals with kidney disease and to the effects of the devices and device placement on kidney health. Cardiac devices can be categorized broadly into cardiac implantable electronic devices, structural devices, and circulatory assist devices. Cardiac implantable electronic devices include devices for monitoring and managing cardiac electrical activity and devices for monitoring hemodynamics. Structural devices modify cardiac structure and include valve prostheses, valve repair clips, devices for treating atrial septal abnormalities, left atrial appendage closure devices, and interatrial shunt devices. Circulatory assist devices support the failing heart or support cardiac function during high-risk cardiac procedures. Evidence for the use of these devices in individuals with kidney disease, effects of the devices on kidney health and function, specific considerations with devices in kidney disease, and important knowledge gaps are surveyed in this article. With the growing prevalence of combined cardiorenal disease and the increasing variety of cardiac devices, kidney disease considerations are an important aspect of device therapy.

Remote Patient Management May Reduce All-Cause Mortality in Patients With Heart-Failure and Renal Impairment

Background

Remote patient management (RPM) in heart failure (HF) patients has been investigated in several prospective randomized trials. The Telemedical Interventional Management in Heart Failure II (TIM-HF2)-trial showed reduced all-cause mortality and hospitalizations in heart failure (HF) patients using remote patient management (RPM) vs. usual care (UC). We report the trial's results for prespecified eGFR-subgroups.

Methods

TIM-HF2 was a prospective, randomized, controlled, parallel-group, unmasked (with randomization concealment), multicenter trial. A total of 1,538 patients with stable HF were enrolled in Germany from 2013 to 2017 and randomized to RPM (+UC) or UC. Using CKD-EPI-formula at baseline, prespecified subgroups were defined. In RPM, patients transmitted their vital parameters daily. The telemedical center reviewed and co-operated with the patient's General Practitioner (GP) and cardiologist. In UC, patients were treated by their GPs or cardiologist applying the current guidelines for HF management and treatment. The primary endpoint was the percentage of days lost due to unplanned cardiovascular hospitalizations or death, secondary outcomes included hospitalizations, all-cause, and cardiovascular mortality.

Results

Our sub analysis showed no difference between RPM and UC in both eGFR-subgroups for the primary endpoint (<60 ml/min/1.73 m2: 40.9% vs. 43.6%, p = 0.1, ≥60 ml/min/1.73 m2 26.5 vs. 29.3%, p = 0.36). In patients with eGFR < 60 ml/min/1.73 m2, 1-year-survival was higher in RPM than UC (89.4 vs. 84.6%, p = 0.02) with an incident rate ratio (IRR) 0.67 (p = 0.03). In the recurrent event analysis, HF hospitalizations and all-cause death were lower in RPM than UC in both eGFR-subgroups (<60 ml/min/1.73 m2: IRR 0.70, p = 0.02; ≥60 ml/min/1.73 m2: IRR 0.64, p = 0.04). In a cox regression analysis, age, NT-pro BNP, eGFR, and BMI were associated with all-cause mortality.

Conclusion

RPM may reduce all-cause mortality and HF hospitalizations in patients with HF and eGFR < 60 ml/min/1.73 m2. HF hospitalizations and all-cause death were lower in RPM in both eGFR-subgroups in the recurrent event analysis. Further studies are needed to investigate and confirm this finding.

Emerging Treatments of Cardiorenal Syndrome: An Update on Pathophysiology and Management

Cardiorenal syndrome refers to combined cardiac and renal dysfunction that adversely impacts both organs and is also associated with severe clinical outcomes. The pathophysiology is believed to be multifactorial and complex. Increased central venous pressure and intra-abdominal pressure, overactivation of the Renin-Angiotensin-Aldosterone System (RAAS), systemic illnesses like sepsis, amyloidosis, diabetes are important factors in developing the cardiorenal syndrome. Our review article attempts to review the pathophysiology and treatment aspect of cardiorenal syndrome and explores potential therapeutic strategies that can be adopted for the management.

We searched PubMed, EMBASE, Google Scholar for relevant articles using different keywords and Medical Subject Headings, and finalized 38 articles to be included in our study. Cardiorenal syndrome management aims to eliminate venous congestion and fluid retention, which leads to improved cardiorenal status. This is usually achieved using pharmacologic agents like diuretics, vasodilators, inotropes, angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin II receptor blockers (ARBs), neprilysin inhibitors, and extracorporeal methods like ultrafiltration. The use of therapeutic agents such as sodium-glucose co-transporter 2 inhibitors and tolvaptan (a vasopressin V2 receptor antagonist), and cardiac resynchronization therapy has also been shown to have potential benefits in managing the disease. These agents can be instrumental in the management and require large-scale clinical trials specifically aimed at improving cardiorenal outcomes based on severity and type of cardiorenal syndrome.

Cardiorenal status using amino-terminal pro-brain natriuretic peptide and cystatin C on cardiac resynchronization therapy outcomes: From the BIOCRT Study

BACKGROUND

Cardiorenal syndrome comprises a heterogeneous group of disorders characterized by acute or chronic cardiac and renal dysfunction.

OBJECTIVE

The purpose of this study was to determine the effect of cardiorenal status using a dual-marker strategy with amino-terminal pro-brain natriuretic peptide (NT-proBNP) and cystatin C on cardiac resynchronization therapy (CRT) outcomes.

METHODS

In 92 patients (age 66 ± 13 years; 80% male; left ventricular ejection fraction 26% ± 7%), NT-proBNP and cystatin C levels were measured at CRT implantation and at 1 month. NT-proBNP >1000 pg/mL and cystatin C >1 mg/L were considered high. Baseline cardiorenal patients were defined as having high NT-proBNP and cystatin C. At 1 month, CRT patients were categorized as (1) irreversible cardiorenal if cystatin C was persistently high; (2) progressive cardiorenal with transition from low to high cystatin C; (3) reversible cardiorenal with transition from high to low cystatin C; and (4) "normal" with stable low cystatin C. Outcomes were 6-month clinical and echocardiographic CRT response and 2 -year major adverse cardiovascular event (MACE).

RESULTS

Compared to patients with low NT-proBNP and cystatin C, cardiorenal patients had >9-fold increase risk of CRT nonresponse (odds ratio uncompensated 9.0; compensated 36.4; both P ≤.004) and >6-fold risk of MACE (hazard ratio uncompensated 8.5; P = .005). Compared to "normal" and reversible patients (referent), irreversible patients had a 9-fold increase for CRT nonresponse (odds ratio 9.1; P <.001) and had >4-fold risk of MACE (adjusted hazard ratio 5.1; P <.001). Irreversible patients were most likely echocardiographic CRT nonresponders.

CONCLUSION

Cardiorenal status by NT-proBNP and cystatin C can identify high-risk CRT patients, and those with both elevated concentrations have worse prognosis.

Usefulness of the CRT-SCORE for Shared Decision Making in Cardiac Resynchronization Therapy in Patients With a Left Ventricular Ejection Fraction of ≤35

Individualized estimation of prognosis after cardiac resynchronization therapy (CRT) remains challenging. Our aim was to develop a multiparametric prognostic risk score (CRT-SCORE) that could be used for patient-specific clinical shared decision making about CRT implantation. The CRT-SCORE was derived from an ongoing CRT registry, including 1,053 consecutive patients (age 67 ± 10 years, 76% male). Using preimplantation variables, 100 multiple imputed datasets were generated for model calibration. Based on multivariate Cox regression models, cross-validated linear prognostic scores were calculated, as well as survival fractions at 1 and 5 years. Specifically, the CRT-SCORE was calculated using atrioventricular junction ablation, age, gender, etiology, New York Heart Association class, diabetes, hemoglobin level, renal function, left bundle branch block, QRS duration, atrial fibrillation, left ventricular systolic and diastolic functions, and mitral regurgitation, and showed a good discriminative ability (areas under the curve 0.773 at 1 year and 0.748 at 5 years). During the long-term follow-up (median 60 months, interquartile range 31 to 85), all-cause mortality was observed in 494 (47%) patients. Based on the distribution of the CRT-SCORE, lower- and higher-risk patient groups were identified. Estimated mean survival rates of 98% at 1 year and 92% at 5 years were observed in the lowest 5% risk group (L5 CRT-SCORE: -4.42 to -1.60), whereas the highest 5% risk group (H5 CRT-SCORE: 1.44 to 2.89) showed poor survival rates: 78% at 1 year and 22% at 5 years. In conclusion, the CRT-SCORE allows accurate prediction of 1- and 5-year survival rates after CRT using readily available and CRT-specific clinical, electrocardiographic, and echocardiographic parameters. The model may assist clinicians in counseling patients and in decision making.

Prescription of Guideline-Recommended Implantable Cardioverter Defibrillator and Cardiac Resynchronization Therapy Among Patients Hospitalized With Heart Failure and Varying Degrees of Renal Function

Implantable cardioverter defibrillators (ICD) and cardiac resynchronization therapy (CRT) reduce mortality in many patients with heart failure (HF), but the current use and effectiveness of ICD/CRT in patients with chronic kidney disease (CKD) are uncertain. We examined associations between kidney function and guideline-recommended prescription of ICD/CRT in the Get With The Guidelines-Heart Failure registry, a performance improvement program for hospitalized patients with HF. We compared differences in ICD and CRT prescription between the following categories of estimated glomerular filtration rate (eGFR; mL/min/1.73 m²): ≥60, 59 to 30, <30, and dialysis dependent. From 2008 through 2014, 26,286 patients were eligible for ICD or CRT, and 16,123(61%) had an eGFR <60. De novo ICD and CRT prescription in this group was low at 45% and 30.5%, respectively. Compared to patients with eGFR ≥60, patients with eGFR 30 to 59 were more likely to receive an ICD (adjusted odds ratio [aOR] 1.08, 95% confidence intervals [CI] 1.01 to 1.14), whereas dialysis patients were less likely (aOR 0.61, 95% CI 0.5 to 0.76). Worse kidney function was associated with a decreased likelihood of CRT prescription (aOR 0.97 per 10 ml/min eGFR decrease, p = 0.03). During the study period, the likelihood of both ICD and CRT prescription increased over time among patients with CKD (ICD aOR 1.12, 95% CI 1.07 to 1.18; CRT aOR 1.14, 95% CI 1.06 to 1.23, per year). Prescription of an ICT/CRT was associated with greater 1-year survival in all eGFR groups. In conclusion, there are significant CKD-based differences in prescription of ICD and CRT in HF. However, given the current state of evidence, it is unclear whether improved prescription of ICD and CRT in the CKD population will result in improvement in outcomes.

An Evidence-Based Approach to Conducting Systematic Reviews on CKD

With the growing need to integrate best evidence to inform clinical care, systematic reviews have continued to flourish. Although this type of review is integral to the synthesis of evidence-based information, systematic reviews are often conducted omitting well-established processes that ensure the validity and replicability of the study; elements of which are integral based on standards developed by the Cochrane Collaboration and the National Academy of Medicine. This review article will share best practices associated with conducting systematic reviews on the topic of CKD using an 8-step process and an evidence-based approach to retrieving and abstracting data. Optimal methods for conducting systematic review searching will be described, including development of appropriate search strategies and utilization of varied resources including databases, grey literature, primary journals, and handsearching. Processes and tools to improve research teams' coordination and efficiency, including integration of systematic review protocols and sophisticated software to streamline data management, will be investigated. In addition to recommended strategies for surveying and synthesizing CKD literature, techniques for maneuvering the complex field of Nephrology will also be explored.

The Effect of Chronic Kidney Disease on Mortality with Cardiac Resynchronization Therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) improves functional status, reduces heart failure hospitalizations, and decreases mortality. Several comorbidities including renal function affect outcomes with CRT. However, moderate to severe chronic kidney disease (CKD) was an exclusion criterion in the large randomized control trials.

OBJECTIVE

To evaluate the association of renal function on survival following CRT implantation.

METHODS

This was a retrospective analysis of 432 consecutive patients implanted with an implantable cardioverter defibrillator with CRT (CRT-D). The primary end point was defined as death by any cause, and it was determined using hospital records and the U.S. Social Security Death Index. A Kaplan-Meier analysis was performed separating renal dysfunction into renal stage based on glomerular filtration rate. Multivariate analysis was performed to assess the clinical predictors of mortality.

RESULTS

Patients were followed for up to 12 years with a mean follow-up time of 4.3 ± 3.2 years. A total of 164 patients (39.3%) died over the course of the study. Patients with normal and mild renal diseases (Stages 1 and 2) had improved survival compared with those with moderate-, severe-, or end-stage (Stages 3-5) renal disease. This effect remained statistically significant after multivariate analysis. The estimated 5-year mortality was 36.3% for stage 1, 33.4% for stage 2, 40.6% for stage 3, and 62.1% for stage 4/5 kidney disease (P = 0.004 by log-rank test).

CONCLUSION

CKD is a strong and an independent predictor of long-term mortality among patients undergoing CRT-D implantation.

Comparative Effectiveness of CRT-D Versus Defibrillator Alone in HF Patients With Moderate-to-Severe Chronic Kidney Disease

BACKGROUND

Patients with moderate-to-severe chronic kidney disease (CKD) are poorly represented in clinical trials of cardiac resynchronization therapy (CRT).

OBJECTIVES

This study sought to assess the real-world comparative effectiveness of CRT with defibrillator (CRT-D) versus implantable cardioverter-defibrillator (ICD) alone in CRT-eligible patients with moderate-to-severe CKD.

METHODS

We conducted an inverse probability-weighted analysis of 10,946 CRT-eligible patients (ejection fraction <35%, QRS >120 ms, New York Heart Association functional class III/IV) with stage 3 to 5 CKD in the National Cardiovascular Data Registry (NCDR) ICD Registry, comparing outcomes between patients who received CRT-D (n = 9,525) versus ICD only (n = 1,421). Outcomes were obtained via Medicare claims and censored at 3 years. The primary endpoint of heart failure (HF) hospitalization or death and the secondary endpoint of death were assessed with Cox proportional hazards models. HF hospitalization, device explant, and progression to end-stage renal disease were assessed using Fine-Gray models.

RESULTS

After risk adjustment, CRT-D use was associated with a reduction in HF hospitalization or death (hazard ratio [HR]: 0.84; 95% confidence interval [CI]: 0.78 to 0.91; p < 0.0001), death (HR: 0.85; 95% CI: 0.77 to 0.93; p < 0.0004), and HF hospitalization alone (subdistribution HR: 0.84; 95% CI: 0.76 to 0.93; p < 0.009). Subgroup analyses suggested that CRT was associated with a reduced risk of HF hospitalization and death across CKD classes. The incidence of in-hospital, short-term, and mid-term device-related complications did not vary across CKD stages.

CONCLUSIONS

In a nationally representative population of HF and CRT-eligible patients, use of CRT-D was associated with a significantly lower risk of the composite endpoint of HF hospitalization or death among patients with moderate-to-severe CKD in the setting of acceptable complication rates.

Incremental value of cystatin C over conventional renal metrics for predicting clinical response and outcomes in cardiac resynchronization therapy: The BIOCRT study

BACKGROUND

Despite the benefit of CRT in select patients with heart failure (HF), there remains significant need for predicting those at risk for adverse outcomes for this effective but costly therapy. CysC, an emerging marker of renal function, is predictive of worsening symptoms and mortality in patients with HF. This study assessed the utility of baseline and serial measures of cystatin C (CysC), compared to conventional creatinine-based measures of renal function (estimated glomerular filtration rate, eGFR), in predicting clinical outcomes following cardiac resynchronization therapy (CRT).

METHODS

In 133 patients, we measured peripheral venous (PV) and coronary sinus (CS) CysC concentrations and peripheral creatinine levels at the time of CRT implant. Study endpoints included clinical response to CRT at 6 months and major adverse cardiac events (MACE) at 2 years.

RESULTS

While all 3 renal metrics were predictive of MACE (all adjusted p ≤ 0.02), only CysC was associated with CRT non-response at 6 months (adjusted odds ratio 3.6, p = 0.02). CysC improved prediction of CRT non-response (p ≤ 0.003) in net reclassification index analysis compared to models utilizing standard renal metrics. Serial CysC > 1mg/L was associated with 6-month CRT non-response and reduced 6-minute walk distance as well as 2-year MACE (all p ≤ 0.04).

CONCLUSION

In patients undergoing CRT, CysC demonstrated incremental benefit in the prediction of CRT non-response when compared to standard metrics of renal function. Baseline and serial measures of elevated CysC were predictive of CRT non-response and functional status at 6 months as well as long-term clinical outcomes.

Predictors of mortality, LVAD implant, or heart transplant in primary prevention cardiac resynchronization therapy recipients: The HF-CRT score

BACKGROUND

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality among individuals with dyssynchronous systolic heart failure (HF). However, patient outcomes vary, with some at higher risk than others for HF progression and death.

OBJECTIVE

To develop a risk prediction score incorporating variables associated with mortality, left ventricular assist device (LVAD) implant, or heart transplant in recipients of a primary prevention cardiac resynchronization therapy-defibrillator (CRT-D).

METHODS

We followed 305 CRT-D patients from the Prospective Observational Study of Implantable Cardioverter-Defibrillators for the composite outcome of all-cause mortality, LVAD implant, or heart transplant soon after device implantation. Serum biomarkers and electrocardiographic and clinical variables were collected at implant. Multivariable analysis using the Cox proportional hazards model with stepwise selection method was used to fit the final model.

RESULTS

Among 305 patients, 53 experienced the composite endpoint. In multivariable analysis, 5 independent predictors ("HF-CRT") were identified: high-sensitivity C-reactive protein >9.42 ng/L (HR = 2.5 [1.4, 4.5]), New York Heart Association functional class III/IV (HR = 2.3 [1.2, 4.5]), creatinine >1.2 mg/dL (HR = 2.7 [1.4, 5.1]), red blood cell count <4.3 × 10(6)/μL (HR = 2.4 [1.3, 4.7]), and cardiac troponin T >28 ng/L (HR = 2.7 [1.4, 5.2]). One point was attributed to each predictor and 3 score categories were identified. Patients with scores 0-1, 2-3, and 4-5 had a 3-year cumulative event-free survival of 96.8%, 79.7%, and 35.2%, respectively (log-rank, P < .001).

CONCLUSION

A simple score combining clinical and readily available biomarker data can risk-stratify CRT patients for HF progression and death. These findings may help identify patients who are in need of closer monitoring or early application of more aggressive circulatory support.

Cardiorenal syndrome: review of our current understanding

Renal and cardiac diseases are both prevalent and carry significant morbidity and mortality. They share common vascular risk factors and are physiologically interlinked. Dysfunction in one organ affects the other. Concurrent renal and cardiac disease is associated with a poor prognosis. This close relationship is reflected through cardiorenal syndrome. A classification system has been proposed; however, the underlying process is complex and multifactorial. Management of this syndrome focuses on improving heart function, reducing volume overload, and managing heart failure and chronic kidney disease. This, however, is challenging, limited by paucity of evidence and may lead to suboptimal therapy. Increased recognition of this syndrome should raise awareness in providing early therapy and avoiding adverse outcomes due to under-treatment. In this article, we provide an overview of our current understanding of cardiorenal syndrome, as well as its pathophysiology and treatment options.

Cardiac Resynchronization Therapy in CKD Stage 4 Patients

BACKGROUND AND OBJECTIVES

Cardiac resynchronization therapy (CRT) is a well established heart failure treatment that has shown to improve renal function. However, landmark CRT trials excluded patients with severe renal dysfunction. Therefore, this study evaluated the effect of CRT on renal function and long-term prognosis in patients with stage 4 CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study evaluated 73 consecutive CRT patients (71±10 years) with stage 4 CKD who underwent echocardiographic and renal function evaluation at baseline and 6-month follow-up between 2000 and 2012. As a control group, 18 patients with stage 4 CKD who received an implantable cardioverter defibrillator (ICD) were selected. CRT recipients with ≥15% reduction in left ventricular end-systolic volume at 6-month follow-up were classified as CRT responders. During long-term follow-up (median, 33 months), appropriate defibrillator therapy, heart failure hospitalizations, and all-cause mortality (combined end point) were recorded.

RESULTS

At 6-month follow-up, a significant reduction in left ventricular end-systolic volume was observed in CRT patients compared with patients with ICD (from 159±78 to 145±78 ml in CRT patients and from 126±54 to 119±49 ml in ICD patients; P=0.05), and CRT response was observed in 22 patients (30%). Compared with ICD patients, eGFR improved among CRT patients (from 25±4 to 30±9 ml/min per 1.73 m(2); interaction time and group, P=0.04) and was more pronounced among CRT responders (25±3 to 34±9 ml/min per 1.73 m(2); P<0.001). The combined end point was observed in 17 ICD and 62 CRT patients. CRT patients showed superior survival compared with ICD patients (log-rank P=0.03). More importantly, CRT response was independently associated with improved survival free from the combined end point (hazard ratio, 0.51; 95% confidence interval, 0.27 to 0.98; P=0.04) after adjustment for clinical and echocardiographic parameters.

CONCLUSIONS

Response to CRT occurs in approximately 30% of patients with stage 4 CKD, which is less than in the average CRT population. CRT was associated with better clinical outcome, and particularly, CRT response was associated with improvement in eGFR and better long-term prognosis.

Co-Morbidities and Cardiac Resynchronization Therapy: When Should They Modify Patient Selection?

Cardiac resynchronization therapy (CRT) improves symptoms, reduces heart failure related hospitalizations and death in selected patients with heart failure. Based on thousands of patients enrolled in major clinical landmark trials, current guidelines describe in relatively precise terms which cardiac patients should receive a device. However, clinical trials often excluded sicker patients leaving clinicians with the dilemma of how to treat real-life patients with major co-morbidities, frailty, and increasing age, who are otherwise candidates for CRT implantation. This review investigates results from clinical trials and available observational data on the influence of co-morbidities on CRT benefit in order to provide better insight of when and why co-morbidities should modify patient selection for CRT.

The impact of intravenous ferric carboxymaltose on renal function: an analysis of the FAIR-HF study

AIMS

Anaemia and iron deficiency are constituents of the cardio-renal syndrome in chronic heart failure (CHF). We investigated the effects of i.v. iron in iron-deficient CHF patients on renal function, and the efficacy and safety of this therapy in patients with renal dysfunction.

METHODS AND RESULTS

The FAIR-HF trial randomized 459 CHF patients with iron deficiency (ferritin <100 µg/L, or between 100 and 299 µg/L if transferrin saturation was <20%): 304 to i.v. ferric carboxymaltose (FCM) and 155 to placebo, and followed-up for 24 weeks. Renal function was assessed at baseline and at weeks 4, 12, and 24, using the estimated glomerular filtration rate (eGFR, mL/min/1.73 m(2) ), calculated from the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. At baseline, renal function was similar between groups (62.4 ± 20.6 vs. 62.9 ± 23.4 mL/min/1.73 m(2) , FCM vs. placebo). Compared with placebo, treatment with FCM was associated with an increase in eGFR [treatment effect: week 4, 2.11 ± 1.21 (P = 0.082); week 12, 2.41 ± 1.33 (P = 0.070); and week 24, 2.98 ± 1.44 mL/min/1.73 m(2) (P = 0.039)]. This effect was seen in all pre-specified subgroups (P > 0.20 for interactions). No interaction between the favourable effects of FCM and baseline renal function was seen for the primary endpoints [improvement in Patient Global Assessment (P = 0.43) and NYHA class (P = 0.37) at 24 weeks]. Safety and adverse event profiles were similar in patients with baseline eGFR <60 and ≥60 mL/min/1.73 m(2) .

CONCLUSIONS

Treatment of iron deficiency in CHF patients with i.v. FCM was associated with an improvement in renal function. FCM therapy was effective and safe in CHF patients with renal dysfunction.

Outcomes of infected cardiovascular implantable devices in dialysis patients

BACKGROUND/AIMS

Dialysis patients are at a higher risk for cardiovascular implantable electronic device (CIED) infection-related hospitalizations. We compared the outcomes and cost for dialysis and non-dialysis patients hospitalized with CIED infections.

METHODS

We conducted a retrospective analysis of the Nationwide Inpatient Sample (NIS) discharge records from 2005 to 2010. Patients with CIED infections were identified using ICD-9 codes for device-related infections or device procedure along with bacteremia, endocarditis or systemic infection. Dialysis patients were identified using ICD-9 codes. Multivariable logistic and linear regressions were performed to examine in-hospital mortality, length of stay and cost.

RESULTS

Of the 87,798 estimated hospitalizations with CIED infections, 6,665 (7.6%) were dialysis patients. CIED-infection-related hospitalization has increased over time among dialysis patients. In-hospital mortality was higher among dialysis patients (13.6% vs. 5.9%, p < 0.001). In the multivariable model, dialysis patients had higher odds of in-hospital mortality (odds ratio 1.98; 95% CI: 1.6, 2.4) compared to the non-dialysis group. Dialysis patients had a longer median length of stay (12 days vs. 7 days, p < 0.001) and majority required extended care facility upon discharge (51.2% vs. 35.0%, p < 0.001) compared to the non-dialysis group. Dialysis status was associated with 50.3% increased cost of hospitalization (p < 0.001).

CONCLUSION

CIED-infection related hospitalization is increasing among patients undergoing dialysis and is associated with higher in-hospital mortality, longer hospital stay and higher costs of hospitalization. Future studies should examine the reasons for such a high risk and find means to improve outcomes in dialysis population.

Influence of renal impairment on myocardial function in outpatients with systolic heart failure: an echocardiographic and cardiac biomarker study

BACKGROUND

Renal dysfunction (RD) is associated with poor outcome in systolic heart failure (HF). Left ventricular ejection fraction (LVEF) is not depressed to a greater extent in patients with RD compared to patients with normal renal function, but it is relatively unknown whether other measures of myocardial function are impaired by RD. The objective of the present study is to evaluate whether RD in systolic HF is associated with excessive impairment of myocardial function, evaluated by strain analysis and cardiac biomarkers.

METHODS

Patients with LVEF <0.45% were enrolled from an outpatient HF clinic. The patients underwent advanced echocardiography. Glomerular filtration rate was estimated by the CKD-EPI equation (eGFR) and patients grouped by eGFR: eGFR group-I, ≥ 90 ml/min/1.73 m(2); eGFR group-II, 60-89 ml/min/1.73 m(2); and eGFR group-III, ≤ 59 ml/min/1.73 m(2). Multivariate regression models were developed to evaluate the associations between eGFR groups, echocardiographic measures and cardiac biomarkers.

RESULTS

A total of 149 patients participated in the study. Median age was 69 years, 26% were female; LVEF was 33%. Patients with a low eGFR were older (P < 0.001), but there were no differences in frequency of atrial fibrillation, hypertension, diabetes and ischemic heart disease between eGFR groups (P > 0.05 for all). RD was associated with impaired global longitudinal strain (P = 0.018), increased E/e' (P = 0.032), larger left atria (P = 0.038) and increased levels of proANP (P < 0.001), NT-proBNP (P < 0.001) and troponin I (P = 0.019) after adjustment for traditional confounders.

CONCLUSIONS

Echocardiographic measures and biomarkers reflecting different aspects of myocardial function are impaired in systolic HF patients with RD and the increased mortality risk in these patients may partly be explained by a depressed cardiac function.

Safety and effectiveness of bariatric surgery in dialysis patients and kidney transplantation candidates

BACKGROUND

Chronic renal disease is known to adversely affect the results of bariatric surgery. There is a paucity of literature on the safety and effectiveness of bariatric surgery on dialysis patients who are at very advanced stages in their renal disease. The objective of this study was to determine the safety and effectiveness of bariatric surgery in dialysis patients.

METHODS

A retrospective review of a prospectively collected database was conducted for dialysis patients who underwent bariatric surgery between January 2006 and January 2012. Age, gender, body mass index (BMI), cause of renal failure, associated co-morbidities, type of surgery, early and late complications, and mortality were collected.

RESULTS

Of the 3048 patients undergoing bariatric surgery during the study period, 21 dialysis patients (.7%) were identified. Eighteen patients underwent laparoscopic Roux-en-Y gastric bypass (LRYGB), 2 patients underwent laparoscopic sleeve gastrectomy, and 1 patient underwent laparoscopic adjustable gastric banding. Mean preoperative BMI was 47.1±5.5 kg/m(2), and BMI decreased to 35.3±8.4 kg/m(2) after a mean follow-up period of 27.6 months (range = 1.4-78.0 mo). Early major complications (<30 days of surgery) occurred in 2 patients (1 anastomotic leak and 1 anastomotic stricture). Four patients had a late complication, including 1 marginal ulcer with bleeding managed endoscopically, 1 small bowel obstruction requiring laparoscopic lysis of adhesions, 1 cholecystitis requiring cholecystectomy, and 1 anastomotic stricture requiring endoscopic dilation. There was 1 death in this cohort, at 45 days after LRYGB, that was unrelated to a surgery.

CONCLUSIONS

Chronic renal failure requiring dialysis should not be considered a contraindication to bariatric surgery. Our experience with this patient population has shown excellent medium-term weight loss and an acceptable (albeit increased) risk/benefit ratio.