Adaptive Servo-Ventilation Has More Favorable Acute Effects on Hemodynamics Than Continuous Positive Airway Pressure in Patients With Heart Failure

Analysis of the effect of CPAP on hemodynamics using clinical data and a theoretical model: CPAP therapy decreases cardiac output mechanically but increases it via afterload reduction

BACKGROUND

Noninvasive positive pressure ventilation (NIPPV) has been established as an effective treatment for heart failure. Positive airway pressure such as continuous positive airway pressure (CPAP) increases cardiac output (CO) in some patients but decreases it in others. However, the mechanism behind such unpredictable responses remains undetermined.

METHODS AND RESULTS

We measured hemodynamic parameters of 38 cases using Swan-Ganz catheter before and after CPAP in chronic heart failure status. In those whose CO increased by CPAP, pulmonary vascular resistance (PVR) was significantly decreased and SpO2 significantly increased, but the other parameters were not changed. On the other hand, PVR was not changed, but systemic vascular resistance (SVR) was increased in those whose CO decreased by CPAP. To explain this phenomenon, we simulated the cardiovascular system using a cardiac model of time-varying elastance. In this model, it was indicated that CPAP decreases CO irrespective of cardiac function or filling status under constant PVR condition. However, when reduction of PVR by CPAP was taken into account, an increase in CO was expected especially in the hypervolemic and low right ventricle (RV) systolic function cases.

CONCLUSIONS

CPAP would increase CO only where PVR can be reduced by CPAP therapy, especially in the case with hypervolemia and/or low RV systolic function. Understanding the underlying mechanism should help identify the patients for whom NIPPV would be effective.

The efficacy and safety of adaptive servo-ventilation therapy for heart failure with preserved ejection fraction

It is unclear whether adaptive servo-ventilation (ASV) therapy for heart failure with preserved ejection fraction (HFpEF) is effective. The aim of this study was to investigate the details of ASV use, and to evaluate the effectiveness and safety of ASV in real-world HFpEF patients. We retrospectively enrolled 36 HFpEF patients at nine cardiovascular centers who initiated ASV therapy during hospitalization or on outpatient basis and were able to continue using it at home from 2012 to 2017 and survived for at least one year thereafter. The number of hospitalizations for heart failure (HF) during the 12 months before and 12 months after introduction of ASV at home was compared. The median number of HF hospitalizations for each patient was significantly reduced from 1 [interquartile range: 1-2] in the 12 months before introduction of ASV to 0 [0-0] in the 12 months after introduction of ASV (p < 0.001). In subgroup analysis, reduction in heart failure hospitalization was significantly greater in female patients, patients with a body mass index < 25, and those with moderate or severe tricuspid valve regurgitation. In patients with HFpEF, the number of HF hospitalizations was significantly decreased after the introduction of ASV. HFpEF patients with female sex, BMI < 25, or moderate to severe tricuspid valve regurgitation are potential candidates who might benefit from ASV therapy.

Patterns of adaptive servo-ventilation settings in a real-life multicenter study: pay attention to volume! : Adaptive servo-ventilation settings in real-life conditions

Backgrounds

To explain the excess cardiovascular mortality observed in the SERVE-HF study, it was hypothesized that the high-pressure ASV default settings used lead to inappropriate ventilation, cascading negative consequences (i.e. not only pro-arrythmogenic effects through metabolic/electrolyte abnormalities, but also lower cardiac output). The aims of this study are: i) to describe ASV-settings for long-term ASV-populations in real-life conditions; ii) to describe the associated minute-ventilations (MV) and therapeutic pressures for servo-controlled-flow versus servo-controlled-volume devices (ASV-F Philips®-devices versus ASV-V ResMed®-devices).

Methods

The OTRLASV-study is a cross-sectional, 5-centre study including patients who underwent ASV-treatment for at least 1 year. The eight participating clinicians were free to adjust ASV settings, which were compared among i) initial diagnosed sleep-disordered-breathing (SBD) groups (Obstructive-Sleep-Apnea (OSA), Central-Sleep-Apnea (CSA), Treatment-Emergent-Central-Sleep-Apnea (TECSA)), and ii) unsupervised groups (k-means clusters). To generate these clusters, baseline and follow-up variables were used (age, sex, body mass index (BMI), initial diagnosed Obstructive-Apnea-Index, initial diagnosed Central-Apnea-Index, Continuous-Positive-Airway-Pressure used before ASV treatment, presence of cardiopathy, and presence of a reduced left-ventricular-ejection-fraction (LVEF)). ASV-data were collected using the manufacturer’s software for 6 months.

Results

One hundred seventy-seven patients (87.57% male) were analysed with a median (IQ_25–75) initial Apnea-Hypopnea-Index of 50 (38–62)/h, an ASV-treatment duration of 2.88 (1.76–4.96) years, 61.58% treated with an ASV-V. SDB groups did not differ in ASV settings, MV or therapeutic pressures. In contrast, the five generated k-means clusters did (generally described as follows: (C1) male-TECSA-cardiopathy, (C2) male-mostly-CSA-cardiopathy, (C3) male-mostly-TECSA-no cardiopathy, (C4) female-mostly-elevated BMI-TECSA-cardiopathy, (C5) male-mostly-OSA-low-LVEF). Of note, the male-mostly-OSA-low-LVEF-cluster-5 had significantly lower fixed end-expiratory-airway-pressure (EPAP) settings versus C1 (p = 0.029) and C4 (p = 0.007). Auto-EPAP usage was higher in the male-mostly-TECSA-no cardiopathy-cluster-3 versus C1 (p = 0.006) and C2 (p < 0.001). MV differences between ASV-F (p = 0.002) and ASV-V (p < 0.001) were not homogenously distributed across clusters, suggesting specific cluster and ASV-algorithm interactions. Individual ASV-data suggest that the hyperventilation risk is not related to the cluster nor the ASV-monitoring type.

Conclusions

Real-life ASV settings are associated with combinations of baseline and follow-up variables wherein cardiological variables remain clinically meaningful. At the patient level, a hyperventilation risk exists regardless of cluster or ASV-monitoring type, spotlighting a future role of MV-telemonitoring in the interest of patient-safety.

Trial registration

The OTRLASV study was registered on ClinicalTrials.gov (Identifier: NCT02429986). 1 April 2015.

Noninvasive Positive Pressure Ventilation for Acute Decompensated Heart Failure

Noninvasive positive pressure ventilation (NIPPV), which can be applied without endotracheal airway or tracheostomy, has been used as the first-line device for patients with acute decompensated heart failure (ADHF) and cardiogenic pulmonary edema. Positive airway pressure (PAP) devices include continuous PAP, bilevel PAP, and adaptive servoventilation. NIPPV can provide favorable physiologic benefits, including improving oxygenation, respiratory mechanics, and pulmonary and systemic hemodynamics. It can also reduce the intubation rate and improve clinical symptoms, resulting in good quality of life and mortality.

Management of Sleep Apnea Syndromes in Heart Failure

Central sleep apnea (CSA) and obstructive sleep apnea (OSA) are prevalent in heart failure (HF) and associated with a worse prognosis. Nocturnal oxygen therapy may decrease CSA events, sympathetic tone, and improve left ventricular ejection fraction, although mortality benefit is unknown. Although treatment of OSA in patients with HF is recommended, therapy for CSA remains controversial. Continuous positive airway pressure use in HF-CSA may improve respiratory events, hemodynamics, and exercise capacity, but not mortality. Adaptive servo ventilation is contraindicated in patients with symptomatic HF with predominant central sleep-disordered events. The role of phrenic nerve stimulation in CSA therapy is promising.

Advanced positive airway pressure modes: adaptive servo ventilation and volume assured pressure support

INTRODUCTION

Volume assured pressure support (VAPS) and adaptive servo ventilation (ASV) are non-invasive positive airway pressure (PAP) modes with sophisticated negative feedback control systems (servomechanism), having the capability to self-adjust in real time its respiratory controlled variables to patient's respiratory fluctuations. However, the widespread use of VAPS and ASV is limited by scant clinical experience, high costs, and the incomplete understanding of propriety algorithmic differences in devices' response to patient's respiratory changes. Hence, we will review and highlight similarities and differences in technical aspects, control algorithms, and settings of each mode, focusing on the literature search published in this area.

AREAS COVERED

One hundred twenty relevant articles were identified by Scopus, PubMed, and Embase databases from January 2010 to 2016, using a combination of MeSH terms and keywords. Articles were further supplemented by pearling. Recommendations were based on the literature review and the authors' expertise in this area. Expert commentary: ASV and VAPS differ in their respiratory targets and response to a respiratory fluctuation. The VAPS mode targets a more consistent minute ventilation, being recommended in the treatment of sleep related hypoventilation disorders, while ASV mode attempts to provide a more steady breathing airflow pattern, treating successfully most central sleep apnea syndromes.