Interatrial Shunt Treatment for Heart Failure: The Randomized RELIEVE-HF Trial.

BACKGROUND: An interatrial shunt may provide an autoregulatory mechanism to decrease left atrial pressure and improve heart failure (HF) symptoms and prognosis. METHODS: Patients with symptomatic HF with any left ventricular ejection fraction (LVEF) were randomized 1:1 to transcatheter shunt implantation versus a placebo procedure, stratified by reduced (≤40%) versus preserved (>40%) LVEF. The primary safety outcome was a composite of device-related or procedure-related major adverse cardiovascular or neurological events at 30 days compared with a prespecified performance goal of 11%. The primary effectiveness outcome was the hierarchical composite ranking of all-cause death, cardiac transplantation or left ventricular assist device implantation, HF hospitalization, outpatient worsening HF events, and change in quality of life from baseline measured by the Kansas City Cardiomyopathy Questionnaire overall summary score through maximum 2-year follow-up, assessed when the last enrolled patient reached 1-year follow-up, expressed as the win ratio. Prespecified hypothesis-generating analyses were performed on patients with reduced and preserved LVEF. RESULTS: Between October 24, 2018, and October 19, 2022, 508 patients were randomized at 94 sites in 11 countries to interatrial shunt treatment (n=250) or a placebo procedure (n=258). Median (25th and 75th percentiles) age was 73.0 years (66.0, 79.0), and 189 patients (37.2%) were women. Median LVEF was reduced (≤40%) in 206 patients (40.6%) and preserved (>40%) in 302 patients (59.4%). No primary safety events occurred after shunt implantation (upper 97.5% confidence limit, 1.5%; P<0.0001). There was no difference in the 2-year primary effectiveness outcome between the shunt and placebo procedure groups (win ratio, 0.86 [95% CI, 0.61-1.22]; P=0.20). However, patients with reduced LVEF had fewer adverse cardiovascular events with shunt treatment versus placebo (annualized rate 49.0% versus 88.6%; relative risk, 0.55 [95% CI, 0.42-0.73]; P<0.0001), whereas patients with preserved LVEF had more cardiovascular events with shunt treatment (annualized rate 60.2% versus 35.9%; relative risk, 1.68 [95% CI, 1.29-2.19]; P=0.0001; Pinteraction<0.0001). There were no between-group differences in change in Kansas City Cardiomyopathy Questionnaire overall summary score during follow-up in all patients or in those with reduced or preserved LVEF. CONCLUSIONS: Transcatheter interatrial shunt implantation was safe but did not improve outcomes in patients with HF. However, the results from a prespecified exploratory analysis in stratified randomized groups suggest that shunt implantation is beneficial in patients with reduced LVEF and harmful in patients with preserved LVEF. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03499236.

Atrial Mechanics, Atrial Cardiomyopathy and Impact of Atrial Interventions.

Our comprehension of atrial mechanics, atrial cardiomyopathy and their clinical implications across various cardiovascular conditions has advanced significantly. Atrial interventions can have differing effects on atrial mechanics. With the rapid increase in the use of atrial interventions, it is crucial for investigators and clinicians to acknowledge the potential adverse effects of these interventions on atrial mechanics that might not be clinically significant at the time of interventions. Recognizing the preclinical stage of atrial maladaptation might enable early interventions before the development of irreversible atrial remodeling and clinical manifestation. We review normal atrial function and mechanics, and atrial cardiomyopathy in select cardiovascular conditions. We also summarize and discuss the current evidence of the impact of various atrial interventions on atrial function and mechanics.

Acute heart failure: current pharmacological treatment and perspectives.

Acute heart failure (AHF) represents the most frequent cause of unplanned hospital admission in patients older than 65 years. Symptoms and clinical signs of AHF (e.g. dyspnoea, orthopnoea, oedema, jugular vein distension, and variation of body weight) are mostly related to systemic venous congestion secondary to various mechanisms including extracellular fluids, increased ventricular filling pressures, and/or auto-transfusion of blood from the splanchnic into the pulmonary circulation. Thus, the initial management of AHF patients should be mostly based on decongestive therapies on admission followed, before discharge, by rapid implementation of guideline-directed oral medical therapies for heart failure. The therapeutic management of AHF requires the identification and rapid diagnosis of the disease, the diagnosis of the cause (or triggering factor), the evaluation of severity, the presence of comorbidities, and, finally, the initiation of a rapid treatment. The most recent guidelines from ESC and ACC/AHA/HFSA have provided updated recommendations on AHF management. Recommended pharmacological treatment for AHF includes diuretic therapy aiming to relieve congestion and achieve optimal fluid status, early and rapid initiation of oral therapies before discharge combined with a close follow-up. Non-pharmacological AHF management requires risk stratification in the emergency department and non-invasive ventilation in case of respiratory failure. Vasodilators should be considered as initial therapy in AHF precipitated by hypertension. On the background of recent large randomized clinical trials and international guidelines, this state-of-the-art review describes current pharmacological treatments and potential directions for future research in AHF.

Sustained Reduction in Pulmonary Artery Pressures and Hospitalizations During 2 Years of Ambulatory Monitoring.

BACKGROUND: Therapy guided by pulmonary artery (PA) pressure monitoring reduces PA pressures and heart failure hospitalizations (HFH) during the first year, but the durability of efficacy and safety through 2 years is not known. METHODS AND RESULTS: The CardioMEMS Post-Approval Study investigated whether benefit and safety were generalized and sustained. Enrollment at 104 centers in the United States included 1200 patients with NYHA Class III symptoms on recommended HF therapies with prior HFH. Therapy was adjusted toward PA diastolic pressure 8-20 mmHg. Intervention frequency and PA pressure reduction were most intense during first 90 days, with sustained reduction of PA diastolic pressure from baseline 24.7 mmHg to 21.0 at 1 year and 20.8 at 2 years for all patients. Patients completing two year follow-up (n = 710) showed similar 2-year reduction (23.9 to 20.8 mmHg), with reduction in PA mean pressure (33.7 to 29.4 mmHg) in patients with reduced left ventricular ejection. The HFH rate was 1.25 events/patient/year prior to sensor implant, 0.54 at 1 year, and 0.37 at 2 years, with 59% of patients free of HFH during follow-up. CONCLUSIONS: Reduction in PA pressures and hospitalizations were early and sustained during 2 years of PA pressure-guided management, with no signal of safety concerns regarding the implanted sensor.

Heart transplantation: focus on donor recovery strategies, left ventricular assist devices, and novel therapies.

Heart transplantation is advocated in selected patients with advanced heart failure in the absence of contraindications. Principal challenges in heart transplantation centre around an insufficient and underutilized donor organ pool, the need to individualize titration of immunosuppressive therapy, and to minimize late complications such as cardiac allograft vasculopathy, malignancy, and renal dysfunction. Advances have served to increase the organ donor pool by advocating the use of donors with underlying hepatitis C virus infection and by expanding the donor source to use hearts donated after circulatory death. New techniques to preserve the donor heart over prolonged ischaemic times, and enabling longer transport times in a safe manner, have been introduced. Mechanical circulatory support as a bridge to transplantation has allowed patients with advanced heart failure to avoid progressive deterioration in hepato-renal function while awaiting an optimal donor organ match. The management of the heart transplantation recipient remains a challenge despite advances in immunosuppression, which provide early gains in rejection avoidance but are associated with infections and late-outcome challenges. In this article, we review contemporary advances and challenges in this field to focus on donor recovery strategies, left ventricular assist devices, and immunosuppressive monitoring therapies with the potential to enhance outcomes. We also describe opportunities for future discovery to include a renewed focus on long-term survival, which continues to be an area that is under-studied and poorly characterized, non-human sources of organs for transplantation including xenotransplantation as well as chimeric transplantation, and technology competitive to human heart transplantation, such as tissue engineering.

The GUIDE-HF trial of pulmonary artery pressure monitoring in heart failure: impact of the COVID-19 pandemic.

AIMS: During the coronavirus disease 2019 (COVID-19) pandemic, important changes in heart failure (HF) event rates have been widely reported, but few data address potential causes for these changes; several possibilities were examined in the GUIDE-HF study. METHODS AND RESULTS: From 15 March 2018 to 20 December 2019, patients were randomized to haemodynamic-guided management (treatment) vs. control for 12 months, with a primary endpoint of all-cause mortality plus HF events. Pre-COVID-19, the primary endpoint rate was 0.553 vs. 0.682 events/patient-year in the treatment vs. control group [hazard ratio (HR) 0.81, P = 0.049]. Treatment difference was no longer evident during COVID-19 (HR 1.11, P = 0.526), with a 21% decrease in the control group (0.536 events/patient-year) and no change in the treatment group (0.597 events/patient-year). Data reflecting provider-, disease-, and patient-dependent factors that might change the primary endpoint rate during COVID-19 were examined. Subject contact frequency was similar in the treatment vs. control group before and during COVID-19. During COVID-19, the monthly rate of medication changes fell 19.2% in the treatment vs. 10.7% in the control group to levels not different between groups (P = 0.362). COVID-19 was infrequent and not different between groups. Pulmonary artery pressure area under the curve decreased -98 mmHg-days in the treatment group vs. -100 mmHg-days in the controls (P = 0.867). Patient compliance with the study protocol was maintained during COVID-19 in both groups. CONCLUSION: During COVID-19, the primary event rate decreased in the controls and remained low in the treatment group, resulting in an effacement of group differences that were present pre-COVID-19. These outcomes did not result from changes in provider- or disease-dependent factors; pulmonary artery pressure decreased despite fewer medication changes, suggesting that patient-dependent factors played an important role in these outcomes. Clinical Trials.gov: NCT03387813.

Haemodynamic-guided management of heart failure (GUIDE-HF): a randomised controlled trial.

BACKGROUND: Previous studies have suggested that haemodynamic-guided management using an implantable pulmonary artery pressure monitor reduces heart failure hospitalisations in patients with moderately symptomatic (New York Heart Association [NYHA] functional class III) chronic heart failure and a hospitalisation in the past year, irrespective of ejection fraction. It is unclear if these benefits extend to patients with mild (NYHA functional class II) or severe (NYHA functional class IV) symptoms of heart failure or to patients with elevated natriuretic peptides without a recent heart failure hospitalisation. This trial was designed to evaluate whether haemodynamic-guided management using remote pulmonary artery pressure monitoring could reduce heart failure events and mortality in patients with heart failure across the spectrum of symptom severity (NYHA funational class II-IV), including those with elevated natriuretic peptides but without a recent heart failure hospitalisation. METHODS: The randomised arm of the haemodynamic-GUIDEed management of Heart Failure (GUIDE-HF) trial was a multicentre, single-blind study at 118 centres in the USA and Canada. Following successful implantation of a pulmonary artery pressure monitor, patients with all ejection fractions, NYHA functional class II-IV chronic heart failure, and either a recent heart failure hospitalisation or elevated natriuretic peptides (based on a-priori thresholds) were randomly assigned (1:1) to either haemodynamic-guided heart failure management based on pulmonary artery pressure or a usual care control group. Patients were masked to their study group assignment. Investigators were aware of treatment assignment but did not have access to pulmonary artery pressure data for control patients. The primary endpoint was a composite of all-cause mortality and total heart failure events (heart failure hospitalisations and urgent heart failure hospital visits) at 12 months assessed in all randomly assigned patients. Safety was assessed in all patients. A pre-COVID-19 impact analysis for the primary and secondary outcomes was prespecified. This study is registered with ClinicalTrials.gov, NCT03387813. FINDINGS: Between March 15, 2018, and Dec 20, 2019, 1022 patients were enrolled, with 1000 patients implanted successfully, and follow-up was completed on Jan 8, 2021. There were 253 primary endpoint events (0·563 per patient-year) among 497 patients in the haemodynamic-guided management group (treatment group) and 289 (0·640 per patient-year) in 503 patients in the control group (hazard ratio [HR] 0·88, 95% CI 0·74-1·05; p=0·16). A prespecified COVID-19 sensitivity analysis using a time-dependent variable to compare events before COVID-19 and during the pandemic suggested a treatment interaction (pinteraction=0·11) due to a change in the primary endpoint event rate during the pandemic phase of the trial, warranting a pre-COVID-19 impact analysis. In the pre-COVID-19 impact analysis, there were 177 primary events (0·553 per patient-year) in the intervention group and 224 events (0·682 per patient-year) in the control group (HR 0·81, 95% CI 0·66-1·00; p=0·049). This difference in primary events almost disappeared during COVID-19, with a 21% decrease in the control group (0·536 per patient-year) relative to pre-COVID-19, virtually no change in the treatment group (0·597 per patient-year), and no difference between groups (HR 1·11, 95% CI 0·80-1·55; p=0·53). The cumulative incidence of heart failure events was not reduced by haemodynamic-guided management (0·85, 0·70-1·03; p=0·096) in the overall study analysis but was significantly decreased in the pre-COVID-19 impact analysis (0·76, 0·61-0·95; p=0·014). 1014 (99%) of 1022 patients had freedom from device or system-related complications. INTERPRETATION: Haemodynamic-guided management of heart failure did not result in a lower composite endpoint rate of mortality and total heart failure events compared with the control group in the overall study analysis. However, a pre-COVID-19 impact analysis indicated a possible benefit of haemodynamic-guided management on the primary outcome in the pre-COVID-19 period, primarily driven by a lower heart failure hospitalisation rate compared with the control group. FUNDING: Abbott.

The cost of non-response to cardiac resynchronization therapy: characterizing heart failure events following cardiac resynchronization therapy.

AIMS: The aim of this study is to quantify healthcare resource utilization among non-responders to cardiac resynchronization therapy (CRT-NR) by heart failure (HF) events and influence of comorbidities. METHODS AND RESULTS: The ADVANCE CRT registry (2013-2015) prospectively identified responders/CRT-NRs 6 months post-implant using the clinical composite score. Heart failure event rates and associated cost, both overall and separated for inpatient hospitalizations, office visits, emergency room visits, and observational stays, were quantified. Costs of events were imputed from payments for similar real-world encounters in subjects with CRT-D/P devices in the MarketScan™ commercial and Medicare Supplemental insurance claims databases. Effects of patient demographics and comorbidities on event rates and cost were evaluated. Of 879 US patients (age 69 ± 11 years, 29% female, ischaemic disease 52%), 310 (35%) were CRT-NR. Among CRT-NRs vs. responders, more patients developed HF (41% vs. 11%, P < 0.001), HF event rate was higher (67.0 ± 21.7 vs. 11.4 ± 3.7/100 pt-year, P < 0.001), and HF readmission within 30 days was more common [hazard ratio 7.06, 95% confidence interval (2.1-43.7)]. Inpatient hospitalization was the most common and most expensive event type in CRT-NR. Comorbid HF was increased by diabetes, hypertension, and pulmonary disorders. Over 2 years, compared to CRT responders, each CRT-NR resulted in excess cost of $6388 ($3859-$10 483) to Medicare (P = 0.015) or $10 197 ($6161-$17 394) to private insurances (P = 0.014). CONCLUSION: Healthcare expenditures associated with contemporary CRT non-response management are among the highest for any HF patient group. This illustrates an unmet need for interventions to improve HF outcomes and reduce costs among some CRT recipients.

The dynamic relationship between serum chloride and cardiorenal syndrome.

Low serum sodium concentration has long been recognized as an established marker of short- and long-term morbidity and mortality in patients with heart failure (HF), and is commonly included in various risk prediction models. Mechanisms leading to hyponatremia (e.g. maladaptive neurohormonal activation) could also lead to concurrent decline in serum chloride levels. Besides, chloride has distinct biological roles (e.g. modulation of renal tubular sodium transporters) that are relevant to the pathophysiology and therapy of HF, making it a potent cardiorenal connector. Several clinical studies have recently reported on a potentially overlooked link between low serum chloride levels and adverse outcomes in patients with a wide variety of HF syndromes, which could indeed be stronger than that of sodium. While evidence on predictive value of chloride is accumulating in various patient populations and settings, the limited available interventional studies have so far yielded conflicting results. It remains to be elucidated whether hypochloremia represents a marker of disease severity and prognosis, or it is an actual pathogenetic mechanism, hence being a potential novel target of therapy. Current ongoing studies are designed to better understand the mechanistic aspects of the role of hypochloremia in HF and shed light on its clinical applicability.

Central Sleep Apnea in Patients with Heart Failure-How to Screen, How to Treat.

PURPOSE OF REVIEW: Central sleep apnea occurs in up to 50% of heart failure patients and worsens outcomes. Established therapies are limited by minimal supporting evidence, poor patient adherence, and potentially adverse cardiovascular effects. However, transvenous phrenic nerve stimulation, by contracting the diaphragm, restores normal breathing throughout sleep and has been shown to be safe and effective. This review discusses the mechanisms, screening, diagnosis, and therapeutic approaches to CSA in patients with HF. RECENT FINDINGS: In a prospective, multicenter randomized Pivotal Trial (NCT01816776) of transvenous phrenic nerve stimulation with the remede System, significantly more treated patients had a ≥ 50% reduction in apnea-hypopnea index compared with controls, with a 41 percentage point difference between group difference at 6 months (p < 0.0001). All hierarchically tested sleep, quality of life, and daytime sleepiness endpoints were significantly improved in treated patients. Freedom from serious related adverse events at 12 months was 91%. Benefits are sustained to 36 months. Transvenous phrenic nerve stimulation improves quality of life in patients with heart failure and central sleep apnea. Controlled trials evaluating the impact of this therapy on mortality/heart failure hospitalizations and "real world" experience are needed to confirm safety and effectiveness.

The Cardiorenal Syndrome in Heart Failure.

Abnormal fluid handling leads to physiologic abnormalities in multiple organ systems. Deranged hemodynamics, neurohormonal activation, excessive tubular sodium reabsorption, inflammation, oxidative stress, and nephrotoxic medications are important drivers of harmful cardiorenal interactions in patients with heart failure. Accurate quantitative measurement of fluid volume is vital to individualizing therapy for such patients. Blood volume analysis and pulmonary artery pressure monitoring seem the most reliable methods for assessing fluid volume and guiding decongestive therapies. Still the cornerstone of decongestive therapy, diuretics' effectiveness decreases with progression of heart failure. Extracorporeal ultrafiltration, an alternative to diuretics, has been shown to reduce heart-failure events.

How to implant a phrenic nerve stimulator for treatment of central sleep apnea?

BACKGROUND: Central sleep apnea (CSA) is a breathing disorder caused by the intermittent absence of central respiratory drive. Transvenous phrenic nerve stimulation is a new therapeutic option, recently approved by the FDA , for the treatment of CSA. OBJECTIVE: To describe the technique used to implant the transvenous phrenic nerve stimulation system (the remede System, Respicardia, Inc). METHODS: The remede System is placed in the pectoral region, typically on the right side. A single stimulation lead is placed in either the left pericardiophrenic vein (PPV) or the right brachiocephalic vein (RBC). A sensing lead is placed into the azygous vein to detect respiration. RESULTS: In the remede System Pivotal trial, 147 of 151 (97%) patients were successfully implanted with the system. Sixty-two percent of stimulation leads were placed in the PPV and 35% in the RBC. Mean procedure time was 2.7 ± 0.8 hours and 94% of patients were free from implant-related serious adverse events through 6 months. CONCLUSION: In patients with CSA, transvenous phrenic nerve stimulation is an effective and safe therapy with an implant procedure similar to that of cardiac implantable electronic devices.

Transvenous neurostimulation for central sleep apnoea: a randomised controlled trial.

BACKGROUND: Central sleep apnoea is a serious breathing disorder associated with poor outcomes. The remedé system (Respicardia Inc, Minnetonka, MN, USA) is an implantable device which transvenously stimulates a nerve causing diaphragmatic contraction similar to normal breathing. We evaluated the safety and effectiveness of unilateral neurostimulation in patients with central sleep apnoea. METHODS: We recruited patients from 31 hospital-based centres in Germany, Poland, and the USA in this prospective, multicentre, randomised trial. Participants had to have been medically stable for at least 30 days and have received appropriate guideline recommended therapy, be aged at least 18 years, be expected to tolerate study procedures, and willing and able to comply with study requirements. Eligible patients with an apnoea-hypopnoea index (AHI) of at least 20 events per h, tested by a polysomnography, underwent device implantation and were randomly assigned (1:1) by a computer-generated method stratified by site to either stimulation (treatment) or no stimulation (control) for 6 months. The primary effectiveness endpoint in the intention-to-treat population was the comparison of the proportions of patients in the treatment versus control groups achieving a 50% or greater AHI reduction from baseline to 6 months, measured by a full-night polysomnography assessed by masked investigators in a core laboratory. The primary safety endpoint of 12-month freedom from serious adverse events related to the procedure, system, or therapy was evaluated in all patients. This trial is active, but not recruiting, and is registered with ClinicalTrials.gov (NCT01816776). FINDINGS: Between April 17, 2013, and May 28, 2015, we randomly assigned 151 eligible patients to the treatment (n=73) or control (n=78) groups. In the analysis of the intention-to-treat population, significantly more patients in the treatment group (35 [51%] of 68) had an AHI reduction from baseline of 50% or greater at 6 months than had those in the control group (eight [11%] of 73; difference between groups 41%, 95% CI 25-54, p<0·0001). 138 (91%) of 151 patients had no serious-related adverse events at 12 months. Seven (9%) cases of related-serious adverse events occurred in the control group and six (8%) cases were reported in the treatment group. Seven patients died (unrelated to implant, system, or therapy), four deaths (two in treatment group and two in control group) during the 6-month randomisation period when neurostimulation was delivered to only the treatment group and was off in the control group, and three deaths between 6 months and 12 months of follow-up when all patients received neurostimulation. 27 (37%) of 73 patients in the treatment group reported non-serious therapy-related discomfort that was resolved with simple system reprogramming in 26 (36%) patients, but was unresolved in one (1%) patient. INTERPRETATION: Transvenous neurostimulation significantly reduced the severity of central sleep apnoea, including improvements in sleep metrics, and was well tolerated. The clinically meaningful effects of the therapy are supported by the concordant improvements in oxygenation and quality of life, making transvenous neurostimulation a promising therapeutic approach for central sleep apnoea. FUNDING: Respicardia Inc.

Cardiac Resynchronization Therapy in Women.

The benefits of cardiac resynchronization therapy (CRT) on the outcomes of patients with heart failure are unquestionable. Women are under-represented in all CRT studies. Most of the available data show that CRT produces a greater clinical benefit in women than men. In several studies, women have left bundle branch block more frequently than men. Women have a remarkably high (90%) CRT response over a wide range of QRS lengths (130-175 milliseconds). Use of a QRS duration of 150 milliseconds as the threshold for CRT prescription may deny a life-saving therapy to many women likely to benefit from CRT.

Rationale and design of the Aquapheresis Versus Intravenous Diuretics and Hospitalization for Heart Failure (AVOID-HF) trial.

BACKGROUND: In patients hospitalized with acutely decompensated heart failure, unresolved signs and symptoms of fluid overload have been consistently associated with poor outcomes. Regardless of dosing and type of administration, intravenous loop diuretics have not reduced heart failure events or mortality in patients with acutely decompensated heart failure. The results of trials comparing intravenous loop diuretics to mechanical fluid removal by isolated venovenous ultrafiltration have yielded conflicting results. Studies evaluating early decongestive strategies have shown that ultrafiltration removed more fluid and was associated with fewer heart failure-related rehospitalization than intravenous loop diuretics. In contrast, when used in the setting of worsening renal function, ultrafiltration was associated with poorer renal outcomes and no reduction in heart failure events. METHODS: The AVOID-HF trial seeks to determine if an early strategy of ultrafiltration in patients with acutely decompensated heart failure is associated with fewer heart failure events at 90 days compared with a strategy based on intravenous loop diuretics. Study subjects from 40 highly experienced institutions are randomized to either early ultrafiltration or intravenous loop diuretics. In both treatment arms, fluid removal therapies are adjusted according to the patients' hemodynamic condition and renal function. The study was unilaterally terminated by the sponsor in the absence of futility and safety concerns after the enrollment of 221 subjects, or 27% of the originally planned sample size of 810 patients. CONCLUSIONS: The AVOID-HF trial's principal aim is to compare the safety and efficacy of ultrafiltration vs that of intravenous loop diuretics in patients hospitalized with acutely decompensated heart failure. Because stepped treatment approaches are applied in both ultrafiltration and intravenous loop diuretics groups and the primary end point is time to first heart failure event within 90 days, it is hoped that the AVOID-HF trial, despite its untimely termination by the sponsor, will provide further insight on how to optimally decongest patients with fluid-overloaded heart failure.

Design of the remede System Pivotal Trial: A Prospective, Randomized Study in the Use of Respiratory Rhythm Management to Treat Central Sleep Apnea.

BACKGROUND: Central sleep apnea is common in patients with cardiovascular disease and worsens outcomes. There is a lack of established therapies for central sleep apnea, and those available are limited by poor patient adherence and potentially adverse cardiovascular effects, at least in a subset of patients. The remede System (Respicardia, Minnetonka, Minnesota) is a new physiologic treatment that uses transvenous phrenic nerve stimulation to contract the diaphragm, thereby stabilizing gas exchange and restoring normal breathing throughout the sleep period. METHODS: This is a prospective multicenter randomized trial with blinded end points evaluating the safety and efficacy of the remede System. Up to 173 patients with central sleep apnea will be randomized 1:1 to remede System therapy initiated at 1 month after implantation (treatment) or to an implanted remede System that will remain inactive for 6 months (control). Primary efficacy end point is the percentage of patients who experience a reduction in apnea-hypopnea index by a ≥ 50% at 6 months (responder analysis). Primary safety end point is freedom from serious adverse events through 12 months. Secondary end points include sleep-disordered breathing parameters, sleep architecture, Epworth Sleepiness Scale score, and Patient Global Assessment. CONCLUSIONS: This is the 1st randomized controlled trial of the safety and efficacy of the remede System for the treatment of central sleep apnea.

Rationale and Design of the Left Atrial Pressure Monitoring to Optimize Heart Failure Therapy Study (LAPTOP-HF).

BACKGROUND: Daily measurements of left atrial pressure (LAP) may be useful for guiding adjustments in medical therapy that prevent clinical decompensation in patients with severe heart failure (HF). STUDY DESIGN: LAPTOP-HF is a prospective, multicenter, randomized, controlled clinical trial in ambulatory patients with advanced heart failure in which the safety and clinical effectiveness of a physician-directed patient self-management therapeutic strategy based on LAP measured twice daily by means of an implantable sensor will be compared with a control group receiving optimal medical therapy. The trial will enroll up to 730 patients with New York Heart Association functional class III symptoms and either a hospitalization for HF during the previous 12 months or an elevated B-type natriuretic peptide level, regardless of ejection fraction, at up to 75 investigational centers. Randomization to the treatment group or control group will be at a 1:1 ratio in 3 strata based on the ejection fraction (EF > or ≤35%) and the presence of a de novo CRT device indication. SUMMARY: LAPTOP-HF will provide essential information about the role of implantable LAP monitoring in conjunction with a new HF treatment paradigm across the spectrum of HF patients.

Novel Agents for the Prevention and Management of Hyperkalemia.

Hyperkalemia is defined as serum potassium concentrations elevated above the upper limit of normal (> 5.0 mEq/L). It has become more common in cardiovascular practice due to the growing population of patients with chronic kidney disease and the broad application of drugs that modulate renal elimination of potassium by reducing production of angiotensin II (angiotensin-converting enzyme inhibitors, direct renin inhibitors, ß-adrenergic receptor antagonists), blocking angiotensin II receptors (angiotensin receptor blockers), or antagonizing the action of aldosterone on mineralocorticoid receptors (mineralocorticoid receptor antagonists). The risk of hyperkalemia is a major limiting factor for the use of these disease-modifying drugs in both acute and chronic cardiorenal syndromes. Thus, agents to control the plasma concentration of potassium are needed in the multidrug treatment of cardiorenal disease, including chronic kidney disease, heart failure, and acute kidney injury. Novel oral therapies in development for both acute and extended use in the management of hyperkalemia include patiromer sorbitex calcium and sodium zirconium cyclosilicate. Important biochemical differences between these compounds result in unique product profiles and electrolyte outcomes in patients treated for hyperkalemia. This review highlights the major mechanisms of hyperkalemia and key results from randomized trials in a range of clinical scenarios in patients with, and at risk for, hyperkalemia.