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(Stroke. 2007;38:249.)
© 2007 American Heart Association, Inc.

Letters to the Editor

Is the Severity of Sleep Apnea Associated With Ischemic Stroke in the Elderly?

Peretz Lavie, PhD Lena Lavie, PhD

Lloyd Rigelr Sleep Apnea Research Laboratory, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel

An extract of the first 250 words of the full text is provided, because this article has no abstract.

To the Editor:

We read with great interest the article by Munoz et al,¹ who reported that severe sleep apnea defined as apnea-hypopnea index (AHI) 30 significantly increased the risk of ischemic stroke in an elderly population (aged 70 to 100 years) independently of known confounding factors. If true, these findings may have enormous public health implications because almost 1 in 4 participants examined by Munoz et al fell into the category of severe sleep apnea. However, before any firm conclusions can be drawn from this study, the data presented in this article must be clarified.

The authors compared 6-year incidence of ischemic stroke between elderly with AHI 30 and elderly with AHI <30 events/h, as documented by polysomnography. But the presented data on sleep apnea severity raise some important questions. The severity of sleep apnea is usually indexed by 2 measures, the rate of respiratory events—apneas and hypopneas—as used by the authors, and the degree of arterial oxygen desaturation during sleep. Arterial oxygen desaturation is generally quantified by either percent time spent below 90% saturation, or by the minimum saturation during sleep. Generally, severe sleep apnea as indexed by AHI is accompanied by severe oxygen desaturation.

The authors’ Table 2, which presents the sleep apnea data of participants with and without ischemic stroke, reveals significantly higher percentage of "severe" sleep apnea in participants with ischemic stroke (45% versus 23%; P<0.033). The data, however, for arterial oxygen desaturation are perplexing. The authors reported that participants with ischemic stroke spent . . . [Full Text of this Article]

Related Article:

Response to Letter by Lavie and Lavie

Roberto Munoz, Joaquín Duran-Cantolla, Eduardo Martínez-Vila, Jaime Gallego, Ramón Rubio, Felipe Aizpuru, and Germán De La Torre
Stroke 2007 38: 250. [Extract] [Full Text] [PDF]