Phrenic Nerve Stimulation for the Treatment of Central Sleep Apnea: A Pooled Cohort Analysis.

STUDY OBJECTIVES: Early evidence with transvenous phrenic nerve stimulation (PNS) demonstrates improved disease severity and quality of life (QOL) in patients with central sleep apnea (CSA). The goal of this analysis is to evaluate the complete prospective experience with PNS in order to better characterize its efficacy and safety, including in patients with concomitant heart failure (HF). METHODS: Using pooled individual data from the pilot (n = 57) and pivotal (n = 151) studies of the remede System in patients with predominant moderate to severe CSA, we evaluated 12-month safety and 6- and 12-month effectiveness based on polysomnography data, QOL, and cardiac function. RESULTS: Among 208 combined patients (June 2010 to May 2015), a remede device implant was successful in 197 patients (95%), 50/57 pilot study patients (88%) and 147/151 pivotal trial patients (97%). The pooled cohort included patients with CSA of various etiologies, and 141 (68%) had concomitant HF. PNS reduced apnea-hypopnea index (AHI) at 6 months by a median of -22.6 episodes/h (25th and 75th percentile; -38.6 and -8.4, respectively) (median 58% reduction from baseline, P < .001). Improvement in sleep variables was maintained through 12 months of follow-up. In patients with HF and ejection fraction ≤ 45%, PNS was associated with improvement in systolic function from 27.0% (23.3, 36.0) to 31.1% (24.0, 41.5) at 12 months (P = .003). In the entire cohort, improvement in QOL was concordant with amelioration of sleep measures. CONCLUSIONS: Transvenous PNS significantly improves CSA severity, sleep quality, ventricular function, and QOL regardless of HF status. Improvements, which are independent of patient compliance, are sustained at 1 year and are associated with acceptable safety.

Prognostic importance of serum troponin concentration in patients with an implanted cardioverter­defibrillator admitted to the emergency department due to electric shock.

BACKGROUND: High-energy implantable cardioverter-defibrillator (ICD) therapy may increase serum troponin (cTnI) concentration.   Aims: We aimed to assess an impact of cTnI concentration after ICD high-energy therapy on mortality. METHODS: A total of 150 patients aged 64.2 +/- 12.8 years admitted to the Emergency Departments (EDs) due to at least one electrical shock during the last 24 hours with measured serum cTnI concentration at admission were included. Age, gender, comorbidities, shocks' numbers, therapy appropriateness, serum creatinine concentration, and left ventricular ejection fraction were noted for the retrospective analysis. Survival was obtained using the personal identification numbers (PESEL), on November 2018 until death or a period of three years had elapsed (1057 days). RESULTS: cTnI concentration was increased in 92 (61.3%) patients. The mortality rate was related to age - HR: 1.04, 95% CI: 1.01-1.08, p = 0.026; increased cTnI concentration - HR: 2.88, 95% CI: 1.30-6.37, p = 0.009; diabetes - HR: 2.19, 95% CI: 1.09-4.39, p = 0.027; ischemic heart disease - HR: 2.96, 95% CI: 1.11-7.87, p = 0.030, serum creatinine concentration - HR: 2.17, 95% CI: 1.18-4.00, p = 0.013; LVEF (HR 0.95, 95% CI: 0.91-0.99, p = 0.009), and previous or current CABG or PCI (HR: 0.38, 95% CI: 0.15-0.96, p = 0.040 and HR: 0.29, 95% CI: 0.13-0.65, p = 0.003, respectively). CONCLUSIONS: Increased mortality rate in patients with ICD shocks is multifactorial. Increased cTnI concentration at ED admission, but not the number of ICD shocks, is an independent marker of higher long-term mortality.

Phrenic nerve stimulation in patients with central sleep apnea: a single­center experience from pilot and pivotal trials evaluating the remede System.

BACKGROUND: Patients with central sleep apnea (CSA) have recently been shown to have improved sleep metrics and quality of life (QoL) with phrenic nerve stimulation (PNS). AIMS: The aim of this study was to report the results of a partnership between cardiology, sleep medicine, and electrophysiology in a single clinical center as well as the enrollment, implantation, and follow­up experience demonstrating both the safety and efficacy of PNS. METHODS: This analysis included data from the pilot and pivotal trials investigating the effect of PNS using an implantable transvenous system in patients with CSA. We present our experience and data on the enrollment processes, implantation feasibility and safety, sleep indices, and QoL at 6 and 12 months of follow­up. RESULTS: Between June 2010 and May 2015, cardiology patients were prescreened and 588 of them were sent for in­home sleep test. Ninety­six patients were referred for polysomnographic studies, and 33 were enrolled and had an implant attempt, with 31 successfully receiving an implant. The apnea-hypopnea index was reduced in the pilot trial (mean [SD] of 48.7 [15.5] events/h to 22.5 [13.2] events/h; P <0.001) and in the pivotal trial (mean [SD] of 48.3 [18.8] events/h to 26.0 [21.9] events/h; P <0.001). Improvement in QoL was also observed. CONCLUSIONS: We showed that PNS improved sleep metrics and QoL in patients with CSA, which is a result of multiple factors, including a comprehensive coordination between cardiology, sleep medicine, and electrophysiology. This ensures appropriate patient identification leading to safe implantation and full patient compliance during follow­up visits.

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.

[Patient with the intervention of an implantable cardioverter-defibrillator in a hospital emergency department].

OBJECTIVE: Introduction: Implantable cardioverter-defibrillators (ICD) improve prognosis in patients with malignant ventricular arrhythmias. Patients with ICD represent a significant proportion of all Emergency Department (ED) admissions. The number of these visits due to the high-energy therapy or antitachycardia pacing (ATP) delivered by the implanted cardioverter-defibrillator is constantly increasing. The aim: To present the prevalence and type of therapeutic interventions of an ICD in patients admitted to ED in 2014-2017 at two medical centers covering approx. 400 000 residents. PATIENTS AND METHODS: Materials and methods: The patients' documentation was analyzed to find patients admitted to emergency department because of the suspicion of the ventricular arrhythmias' therapy delivered by ICD. RESULTS: Results: In most cases adequate high-energy therapies due to life-threatening ventricular arrhythmias were the reason for hospitalization. We identified 126 patients aged 63.0±12.0 years, 108 (86&) of male and 18 (14&) of female. Among 171 ED admissions 6 were associated with ATP and 149 with high-energy therapy, 10 cases presented with VT without therapies, 5 with fantom shocks and in one case the patient had only a pacemaker but not ICD. The number of ICD shocks ranged from 1 to 108. Inadequate ICD discharges were found in 26 (17.4&) of high energy therapies. CONCLUSION: Conclusions:1. The number of patients with ICD admitted to Emergency Department due to the initiation of high-energy or anti-tachyarrhythmic therapy has been steadily increasing in recent years. 2. In most cases, the reason for the admissions are adequate high-energy therapies, i.e. ICD discharges that disrupt the potentially life threatening arrhythmia. 3. Accurate medical history, the possibility of assessing the heart rate stored in the ICD memory during its intervention form the basis for establishing a plan of action in patients with ICD.

Transvenous stimulation of the phrenic nerve for the treatment of central sleep apnoea: 12 months' experience with the remede® System.

AIMS: Patients with central sleep apnoea (CSA) often have poor quality of life and are at increased risk of morbidity and mortality. This study sought to evaluate the 12-month clinical outcomes of patients with CSA treated with unilateral transvenous phrenic nerve stimulation in the prospective, multicentre, non-randomized remede® System pilot study. METHODS AND RESULTS: Forty-seven patients with CSA were treated with the remede® System (Respicardia Inc., Minnetonka, MN, USA) for a minimum of 3 months. Sleep-disordered breathing parameters were evaluated by polysomnography (PSG) at 3, 6, and 12-month follow-up. Sleep symptoms and quality of life were also evaluated. Forty-one patients completed all follow-up PSGs and were included in the analysis. At 12 months, there was sustained improvement compared with baseline in the apnoea-hypopnoea index (49.9 ± 15.1 vs. 27.5 ± 18.3 events/h, P < 0.001) and central apnoea index (28.2 ± 15.0 vs. 6.0 ± 9.2 events/h, P < 0.001). Sustained improvement in the oxygen desaturation index (46.1 ± 19.1 vs. 26.9 ± 18.0 events/h, P < 0.001), rapid eye movement sleep (11.4 ± 6.1% vs. 17.1 ± 8.0%, P < 0.001), and sleep efficiency (69.3 ± 16.9% vs. 75.6 ± 17.1%, P = 0.024) were also observed. There were also continued favourable effects on sleepiness and quality of life. Three deaths unrelated to remede® System therapy and five serious adverse events occurred over 12 months of follow-up. CONCLUSION: The present study demonstrates that in patients with CSA, unilateral transvenous phrenic nerve stimulation is associated with sustained improvement in key sleep parameters, sleep symptoms, and quality of life over 12 months of follow-up.

Phrenic nerve stimulation for the treatment of central sleep apnea.

OBJECTIVES: The aim of this study was to evaluate chronic, transvenous, unilateral phrenic nerve stimulation to treat central sleep apnea (CSA) in a prospective, multicenter, nonrandomized study. BACKGROUND: CSA occurs predominantly in patients with heart failure and increases the risk for morbidity and mortality. Established therapies for CSA are lacking, and those available are limited by poor patient adherence. METHODS: Fifty-seven patients with CSA underwent baseline polysomnography followed by transvenous phrenic nerve stimulation system implantation and follow-up. Feasibility was assessed by implantation success rate and therapy delivery. Safety was evaluated by monitoring of device- and procedure-related adverse events. Efficacy was evaluated by changes in the apnea-hypopnea index at 3 months. Quality of life at 6 months was evaluated using a sleepiness questionnaire, patient global assessment, and, in patients with heart failure at baseline, the Minnesota Living With Heart Failure Questionnaire. RESULTS: The study met its primary end point, demonstrating a 55% reduction in apnea-hypopnea index from baseline to 3 months (49.5 ± 14.6 episodes/h vs. 22.4 ± 13.6 episodes/h of sleep; p < 0.0001; 95% confidence interval for change: -32.3 to -21.9). Central apnea index, oxygenation, and arousals significantly improved. Favorable effects on quality of life and sleepiness were noted. In patients with heart failure, the Minnesota Living With Heart Failure Questionnaire score significantly improved. Device- or procedure-related serious adverse events occurred in 26% of patients through 6 months post therapy initiation, predominantly due to lead repositioning early in the study. Therapy was well tolerated. Efficacy was maintained at 6 months. CONCLUSIONS: Transvenous, unilateral phrenic nerve stimulation appears safe and effective for treating CSA. These findings should be confirmed in a prospective, randomized, controlled trial. (Chronic Evaluation of Respicardia Therapy; NCT01124370).

Transvenous phrenic nerve stimulation for the treatment of central sleep apnoea in heart failure.

AIMS: Periodic breathing with central sleep apnoea (CSA) is common in heart failure patients and is associated with poor quality of life and increased risk of morbidity and mortality. We conducted a prospective, non-randomized, acute study to determine the feasibility of using unilateral transvenous phrenic nerve stimulation for the treatment of CSA in heart failure patients. METHODS AND RESULTS: Thirty-one patients from six centres underwent attempted transvenous lead placement. Of these, 16 qualified to undergo two successive nights of polysomnography-one night with and one night without phrenic nerve stimulation. Comparisons were made between the two nights using the following indices: apnoea-hypopnoea index (AHI), central apnoea index (CAI), obstructive apnoea index (OAI), hypopnoea index, arousal index, and 4% oxygen desaturation index (ODI4%). Patients underwent phrenic nerve stimulation from either the right brachiocephalic vein (n = 8) or the left brachiocephalic or pericardiophrenic vein (n = 8). Therapy period was (mean ± SD) 251 ± 71 min. Stimulation resulted in significant improvement in the AHI [median (inter-quartile range); 45 (39-59) vs. 23 (12-27) events/h, P = 0.002], CAI [27 (11-38) vs. 1 (0-5) events/h, P≤ 0.001], arousal index [32 (20-42) vs. 12 (9-27) events/h, P = 0.001], and ODI4% [31 (22-36) vs. 14 (7-20) events/h, P = 0.002]. No significant changes occurred in the OAI or hypopnoea index. Two adverse events occurred (lead thrombus and episode of ventricular tachycardia), though neither was directly related to phrenic nerve stimulation therapy. CONCLUSION: Unilateral transvenous phrenic nerve stimulation significantly reduces episodes of CSA and restores a more natural breathing pattern in patients with heart failure. This approach may represent a novel therapy for CSA and warrants further study.