Heterogenous haemodynamic effects of adaptive servoventilation therapy in sleeping patients with heart failure and Cheyne-Stokes respiration compared to healthy volunteers.

This study investigated the haemodynamic effects of adaptive servoventilation (ASV) in heart failure (HF) patients with Cheyne-Stokes respiration (CSR) versus healthy controls. Twenty-seven HF patients with CSR and 15 volunteers were ventilated for 1 h using a new ASV device (PaceWave™). Haemodynamics were continuously and non-invasively recorded at baseline, during ASV and after ventilation. Prior to the actual study, a small validation study was performed to validate non-invasive measurement of Stroke volume index (SVI). Non-invasive measurement of SVI showed a marginal overall difference of -0.03 ± 0.41 L/min/m(2) compared to the current gold standard (Thermodilution-based measurement). Stroke volume index (SVI) increased during ASV in HF patients (29.7 ± 5 to 30.4 ± 6 to 28.7 ± 5 mL/m(2), p < 0.05) and decreased slightly in volunteers (50.7 ± 12 to 48.6 ± 11 to 47.9 ± 12 mL/m(2)). Simultaneously, 1 h of ASV was associated with a trend towards an increase in parasympathetic nervous activity (PNA) in HF patients and a trend towards an increase in sympathetic nervous activity (SNA) in healthy volunteers. Blood pressure (BP) and total peripheral resistance response increased significantly in both groups, despite marked inter-individual variation. Effects were independent of vigilance. Predictors of increased SVI during ASV in HF patients included preserved right ventricular function, normal resting BP, non-ischaemic HF aetiology, mitral regurgitation and increased left ventricular filling pressures. This study confirms favourable haemodynamic effects of ASV in HF patients with CSR presenting with mitral regurgitation and/or increased left ventricular filling pressures, but also identified a number of new predictors. This might be mediated by a shift towards more parasympathetic nervous activity in those patients.

Respiratory effects of adaptive servoventilation therapy in patients with heart failure and Cheyne-Stokes respiration compared to healthy volunteers.

BACKGROUND: Nocturnal adaptive servoventilation (ASV) therapy is now frequently used to treat Cheyne-Stokes respiration (CSR), which is highly prevalent in patients with moderate-to-severe heart failure (HF) and characterized by periodical breathing (hyperventilation). OBJECTIVES: This study analyzed and compared the acute effects of a novel ASV device on carbon dioxide pressure (pCO2) and oxygen saturation (SaO2) in HF patients with CSR and healthy volunteers. The influence of being asleep or awake on the ASV algorithm was also determined. METHODS: All subjects underwent ASV (PaceWave™, ResMed) for 1 h. Transcutaneous pCO2 (PtcCO2) and SaO2 were assessed transcutaneously, while wakefulness was analyzed using EEG recordings. Assessments were made 30 min before and after ASV, and during 1 h of ASV. RESULTS: Twenty HF patients (19 male; age 79 ± 12 years) and 15 volunteers (13 male, age 25 ± 4 years) were included. When awake, ASV was associated with a trend towards a decrease in PtcCO2 and an increase in SaO2 versus baseline in HF patients (34.4 ± 3.2 to 33.7 ± 3.8 mm Hg and 93.8 ± 2.6 to 94.9 ± 2.6%, respectively) and volunteers (39.5 ± 3.0 to 38.2 ± 3.8 mm Hg and 96.9 ± 1.3 to 97.8 ± 0.9%). While asleep during ASV, PtcCO2 increased to 36.3 ± 3.8 mm Hg and SaO2 decreased to 93.8 ± 2.6% in HF patients, with similar changes in volunteers (PtcCO2 41.7 ± 3.0 mm Hg, SaO2 97.1 ± 1.2). All comparisons were statistically significant (p ≤ 0.05, except the PtcCO2 decrease in both groups when awake). CONCLUSIONS: ASV therapy might result in hyperventilation when subjects are awake, but while asleep, PtcCO2 increased to mid-normal values, effects that would be favorable in HF patients with CSR.

Validation of blood pressure monitoring using pulse transit time in heart failure patients with Cheyne-Stokes respiration undergoing adaptive servoventilation therapy.

PURPOSE: Using pulse transit time (PTT) and an ECG appears to be a promising alternative for invasive or noninvasive monitoring of blood pressure (BP). This study assessed the validity of PTT for BP monitoring in clinical practice. METHODS: Twenty-nine patients with chronic heart failure (HF; 27 male, 70.5 ± 9.9 years) and nocturnal Cheyne-Stokes respiration were noninvasively ventilated for one hour using adaptive servoventilation (ASV) therapy (PaceWave, ResMed). BP was measured using two devices (oscillometrically via Task Force Monitor, CNSystems and PTT via SOMNOscreen, Somnomedics) at least every 7 min for 30 min before, during, and after ASV. RESULTS: Mean systolic BP was 118.1 ± 14.4 mmHg vs. 115.9 ± 14.1 mmHg for oscillometric method vs PTT, respectively. Corresponding values for diastolic BP were 72.3 ± 10.3 mmHg and 69.4 ± 11.1 mmHg. While clinically comparable, differences between the two methods were statistically significant (p < 0.05). The difference between the two methods showed an increasing trend over time. A total of 18.5 % of PTT-based measurements could not be analyzed. The direction of a change in BP was opposite for PTT vs oscillometry for 17.0 % and 32.8 % of systolic and diastolic BP measurements, respectively. CONCLUSIONS: When monitoring BP in HF patients, overall BP monitoring using PTT is comparable to oscillometry for a period of 2 h (including a 1-h ASV phase). However, PTT shows a tendency to underestimate BP over time and during ASV.

Trilevel adaptive servoventilation for the treatment of central and mixed sleep apnea in chronic heart failure patients.

BACKGROUND: Sleep-disordered breathing (SDB) in patients with heart failure (HF) is of major prognostic impact, though treatment of simultaneously occurring central and mixed apnea events is challenging. The objective was to examine long-term effects of a new trilevel adaptive servoventilation (ASV) therapy in patients with systolic or diastolic HF. METHODS: A total of 45 consecutive patients with a history of HF, elevated N-terminal prohormone of brain natriuretic peptide levels, objective signs of cardiac dysfunction, and moderate to severe SDB (apnea-hypopnea index [AHI] > or =15/h) with combined central and mixed respiratory events were included in this study and ASV therapy (SOMNOvent CR, Weinmann) was offered. RESULTS: In 38 patients (84%), ASV therapy was successfully initiated, with 23 (51%) patients showing appropriate compliance (device use > or = 4 h/night for > or = 5d/w) after 3.6±1.2 months. In these patients ASV therapy and HF status were re-evaluated. A sustained reduction was achieved in AHI (42.8±17.5/h vs 8.9±5.8/h; p<0.001) and oxygen saturation. Improvements also were recorded in New York Heart Association (NYHA) functional class (2.4±0.5-1.9±0.4; p<0.001) and oxygen uptake during cardiopulmonary exercise testing (VO2 peak, 13.64±3.5-15.8±5.8 ml/kg/min; p<0.002). CONCLUSION: In selected HF patients, trilevel ASV therapy is able to treat SDB with combined central and mixed respiratory events. This treatment is associated with an improvement in HF symptoms and objective cardiopulmonary performance.

Obstructive sleep apnoea: longer respiratory event lengths in patients with heart failure.

This study investigated the effect of heart failure on respiratory patterns in patients with obstructive sleep apnoea (OSA). 39 patients with established OSA (apnoea/hypopnoea index (AHI) >10 events·h(-1)) and either with heart failure (New York Heart Association (NYHA) class II and III, left ventricular-ejection fraction (LVEF) ≤40%; n=26, age mean ± SD 67 ± 9 years) or without heart failure (LVEF ≥50%, N-terminal pro-brain naturic peptide <400 pg·mL(-1); n=13, age 73 ± 6 years) underwent simultaneous right- and left-heart catheterisation within 12 h of cardiorespiratory polygraphy recording. Respiratory patterns of OSA were significantly longer in OSA patients with heart failure versus without heart failure, including mean ± SD cycle length (46.0 ± 10.0 versus 37.8 ± 10.6 s; p=0.024), ventilation length (25.4 ± 6.3 versus 21.3 ± 7.1 s; p=0.044), apnoea length (20.5 ± 4.9 versus 16.5 ± 3.9 s; p=0.013), time-to-peak ventilation (10.6 ± 3.0 versus 8.3 ± 2.5 sc; p=0.021) and circulatory delay (28.5 ± 7.5 versus 22.6 ± 3.7 s; p=0.005). Positive and robust correlations were found between some of these parameters and the degree of congestion in heart failure: cycle length (r=0.53; p=0.006), ventilation length (r=0.55; p=0.004) and time-to-peak ventilation (r=0.47; p=0.015) all increased with a rise in pulmonary capillary wedge pressure. Respiratory patterns in OSA appear to be dependent on cardiac function, with an increase in event lengths as cardiac function decreases. In patients with heart failure, some of these events correlate with the degree of pulmonary congestion.