Can cardiorespiratory polygraphy replace portable polysomnography in the assessment of sleep-disordered breathing in heart failure patients?
OBJECTIVE
Portable polysomnography (PSG) and cardiorespiratory polygraphy are increasingly being used in the assessment of sleep-disordered breathing (SDB) in heart failure patients. Scoring of SDB from cardiorespiratory polygraphy recordings is based only on respiratory signals, while electroencephalographic, electrooculographic and electromyographic channels are taken into account when using PSG recordings. The aim of this study was to assess the agreement between these two scoring methods.


METHODS
An overnight sleep study was performed in 67 heart failure patients using a standard portable polysomnograph. Each recording was scored twice, once using all acquired signals (PSG mode) and, after a median of 64 days, using only respiratory signals (cardiorespiratory mode). Agreement was assessed by Bland-Altman analysis and Cohen's kappa.


RESULTS
We found that (1) more respiratory events were detected using cardiorespiratory analysis [median (25th percentile, 75th percentile), 75 (39, 200) events] compared to analysis of portable PSG [69 (29, 173) events, p < 0.0001], the extra events being, for the vast majority, central in origin; (2) the apnea/hypopnea index (AHI) estimated by cardiorespiratory polygraphy [11.9 (5.7, 30.8)/h] showed a negligible negative bias relative to portable PSG [15.1 (5.7, 33.6)/h; bias, -0.8 (-2.9, 0.4)/h, p = 0.0002]; (3) limits of agreement between the two systems (-6.2/h, 1.7/h) were much smaller than those previously observed between two nights using the same scoring modality; and (4) the kappa coefficient using categorised AHI was 0.89 (95% confidence interval (CI) 0.82, 0.96).


CONCLUSIONS
We found a high degree of agreement between the AHIs obtained from the two scoring methods, thus suggesting that cardiorespiratory polygraphy may be used as an alternative to portable PSG in the assessment of SDB in heart failure patients.
Department of Biomedical Engineering, Fondazione S. Maugeri, IRCCS, Montescano, Italy, giandomenico.pinna@fsm.it.
Gian Domenico
GD
Pinna
Elena
E
Robbi
Fabio
F
Pizza
Anna Eugenia
AE
Taurino
Caterina
C
Pronzato
Maria Teresa
MT
La Rovere
Roberto
R
Maestri
D000328:Adult; D000368:Aged; D005260:Female; D006333:Heart Failure / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D017286:Polysomnography / Q000295:instrumentation*; D011237:Predictive Value of Tests; D020182:Sleep Apnea, Central / Q000175:diagnosis*; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*