Sleep Apnea Syndromes: Morrison D

Fleetham J, Ayas N, Bradley D, Ferguson K, Fitzpatrick M, George C, Hanly P, Hill F, Kimoff J, Kryger M, Morrison D, Series F, Tsai W, Anonymous00098. · Comité des troubles respiratoires du sommeil de la SCT. · Can Respir J. · Pubmed #17315056 links to  free full text

This publication has no abstract.

Fleetham J, Ayas N, Bradley D, Ferguson K, Fitzpatrick M, George C, Hanly P, Hill F, Kimoff J, Kryger M, Morrison D, Series F, Tsai W, Anonymous00045. · Respiratory Medicine, Diamond Health Care Centre, Vancouver, British Columbia V5Z 1M9. · Can Respir J. · Pubmed #17036094 links to  free full text

This publication has no abstract.

Bradley TD, Logan AG, Kimoff RJ, Sériès F, Morrison D, Ferguson K, Belenkie I, Pfeifer M, Fleetham J, Hanly P, Smilovitch M, Tomlinson G, Floras JS, Anonymous00277. · Department of Medicine, University of Toronto, Toronto. · N Engl J Med. · Pubmed #16282177 links to  free full text

Abstract: BACKGROUND: The Canadian Continuous Positive Airway Pressure for Patients with Central Sleep Apnea and Heart Failure trial tested the hypothesis that continuous positive airway pressure (CPAP) would improve the survival rate without heart transplantation of patients who have central sleep apnea and heart failure. METHODS: After medical therapy was optimized, 258 patients who had heart failure (mean age [+/-SD], 63+/-10 years; ejection fraction, 24.5+/-7.7 percent) and central sleep apnea (number of episodes of apnea and hypopnea per hour of sleep, 40+/-16) were randomly assigned to receive CPAP (128 patients) or no CPAP (130 patients) and were followed for a mean of two years. During follow-up, sleep studies were conducted and measurements of the ejection fraction, exercise capacity, quality of life, and neurohormones were obtained. RESULTS: Three months after undergoing randomization, the CPAP group, as compared with the control group, had greater reductions in the frequency of episodes of apnea and hypopnea (-21+/-16 vs. -2+/-18 per hour, P<0.001) and in norepinephrine levels (-1.03+/-1.84 vs. 0.02+/-0.99 nmol per liter, P=0.009), and greater increases in the mean nocturnal oxygen saturation (1.6+/-2.8 percent vs. 0.4+/-2.5 percent, P<0.001), ejection fraction (2.2+/-5.4 percent vs. 0.4+/-5.3 percent, P=0.02), and the distance walked in six minutes (20.0+/-55 vs. -0.8+/-64.8 m, P=0.016). There were no differences between the control group and the CPAP group in the number of hospitalizations, quality of life, or atrial natriuretic peptide levels. An early divergence in survival rates without heart transplantation favored the control group, but after 18 months the divergence favored the CPAP group, yet the overall event rates (death and heart transplantation) did not differ (32 vs. 32 events, respectively; P=0.54). CONCLUSIONS: Although CPAP attenuated central sleep apnea, improved nocturnal oxygenation, increased the ejection fraction, lowered norepinephrine levels, and increased the distance walked in six minutes, it did not affect survival. Our data do not support the use of CPAP to extend life in patients who have central sleep apnea and heart failure.

Arzt M, Floras JS, Logan AG, Kimoff RJ, Series F, Morrison D, Ferguson K, Belenkie I, Pfeifer M, Fleetham J, Hanly P, Smilovitch M, Ryan C, Tomlinson G, Bradley TD, Anonymous00003. · University of Toronto, Toronto, Ontario, Canada. · Circulation. · Pubmed #17562959 links to  free full text

Abstract: BACKGROUND: In the main analysis of the Canadian Continuous Positive Airway Pressure (CPAP) for Patients with Central Sleep Apnea (CSA) and Heart Failure Trial (CANPAP), CPAP had no effect on heart transplant-free survival; however, CPAP only reduced the mean apnea-hypopnea index to 19 events per hour of sleep, which remained above the trial inclusion threshold of 15. This stratified analysis of CANPAP tested the hypothesis that suppression of CSA below this threshold by CPAP would improve left ventricular ejection fraction and heart transplant-free survival. METHODS AND RESULTS: Of the 258 heart failure patients with CSA in CANPAP, 110 of the 130 randomized to the control group and 100 of the 128 randomized to CPAP had sleep studies 3 months later. CPAP patients were divided post hoc into those whose apnea-hypopnea index was or was not reduced below 15 at this time (CPAP-CSA suppressed, n=57, and CPAP-CSA unsuppressed, n=43, respectively). Their changes in left ventricular ejection fraction and heart transplant-free survival were compared with those in the control group. Despite similar CPAP pressure and hours of use in the 2 groups, CPAP-CSA-suppressed subjects experienced a greater increase in left ventricular ejection fraction at 3 months (P=0.001) and significantly better transplant-free survival (hazard ratio [95% confidence interval] 0.371 [0.142 to 0.967], P=0.043) than control subjects, whereas the CPAP-CSA-unsuppressed group did not (for left ventricular ejection fraction, P=0.984, and for transplant-free survival, hazard ratio 1.463 [95% confidence interval 0.751 to 2.850], P=0.260). CONCLUSIONS: These results suggest that in heart failure patients, CPAP might improve both left ventricular ejection fraction and heart transplant-free survival if CSA is suppressed soon after its initiation.

Sériès F, Kimoff RJ, Morrison D, Leblanc MH, Smilovitch M, Howlett J, Logan AG, Floras JS, Bradley TD. · Centre de Pneumologie Hôpital Laval, 2725, Chemin Sainte-Foy, Sainte-Foy, PQ, Canada G1V 4G5. · Chest. · Pubmed #15888821 links to  free full text

Abstract: BACKGROUND: Because patients with chronic heart failure (CHF) can benefit from specific treatment for coexisting obstructive and central sleep apnea (CSA), there is a need to develop accurate screening tools to identify or exclude these sleep-related breathing disturbances (SRBDs) in patients with CHF. OBJECTIVES: To evaluate, prospectively, the diagnostic value of nocturnal home oximetry in identifying SRBD in CHF patients and in distinguishing central events from obstructive events. DESIGN: Blinded comparison of hospital and home oximetry, and polysomnographic nocturnal recordings SETTING: Cardiac heart failure and sleep clinics in three tertiary referral centers. PATIENTS: Fifty consecutive patients who were investigated for participation in the Canadian Continuous Positive Airway Pressure Trial for Congestive Heart Failure with Central Sleep Apnea and were recruited from three different centers. MEASUREMENTS AND RESULTS: Patients underwent two oximetry recordings, one at home and one during a polysomnographic study. The criterion for an SRBD was the presence of > 15 apneas and hypopneas per hour of sleep during polysomnography or an oxygen desaturation index of > 10 events per hour during oximetry. The pattern of desaturation/resaturation during oximetry was also examined to distinguish obstructive events from central events. Using a 2% fall in pulse oximetric saturation as the criterion for oxygen desaturation, home oximetry had a 85% sensitivity and a 93% specificity (p < 0.001) for detecting an SRBD. However, the desaturation/resaturation pattern did not accurately distinguish between obstructive events and central events (eg, 100% sensitivity, 17% specificity for identifying CSA). The interpretation of the oximetry recording was highly consistent between scorers (p < 0.001). CONCLUSIONS: Overnight home oximetry is a sensitive and specific tool for identifying SRBDs in patients with CHF, but not for distinguishing between obstructive and central events in such patients.