To the Editor Dr Jørgensen and colleagues1 reported an increased risk of recurrent stroke within 30 days after surgery in patients with previous stroke compared with those without previous stroke and that the risk was higher the closer to the incident stroke that the surgery was performed. However, this study cannot be interpreted as showing that the risks of surgery are greater if performed closer to the incident stroke because it lacks a crucial control group with recent stroke who did not undergo surgery.
Powers WJ. Time Since Stroke and Risk of Adverse Outcomes After Surgery. JAMA. 2014;312(18):1930. doi:10.1001/jama.2014.13422