05 Oct Transient Ischemic Attack and OSA.
Schipper et al. recently investigated the occurrence of OSA in high risk patients with a TIA. They screened patients from a TIA daycare clinic for having a high risk of OSA. High risk patients had a sleep study. They defined high risk as patients with 2 of the following:
- BMI greater than of equal to 30
- Epworth Sleepiness Score greater than 30
Of the 555 patients with suspected TIA, 77 had a sleep study. OSA was determined with internationally accepted measures of AHI (number of sleep apnoea and hypopnoea events per hour).
25 of these patients had a diagnosis of a TIA, and 18 had cerebral ischemia (34 had other diagnoses). 80% of the TIA patients had OSA, whereas 47% of the cerebral ischemia patients had OSA. When they excluded patients with a cardiovascular history they still found that 75% of TIA patients had OSA and 46% of the cerebral ischemia had OSA. They concluded a higher occurrence of OSA in TIA patients compared to patients without a vascular diagnosis, even after excluding patients with a cardiovascular history.
One of the pitfalls of this study is the screening tool used for high risk patients for having OSA. While snoring, tiredness and BMI are valuable parameters, a more robust and validated tool such as the STOP BANG may have screened patients better and given them better insight into the OSA and TIA relationship. Snoring, tiredness and BMI are all components of the STOP BANG screening tool.