The time since a stroke need not determine when patients undergo elective coronary artery bypass grafting (CABG), say researchers.
"We initially hypothesized that there would be a window of vulnerability after stroke during which CABG should be considered high risk," say Robert Sanders (University College London, UK) and colleagues.
They found that, although previous stroke raised the risk for postoperative stroke and mortality, there was no particular period when patients were at especially high risk.
"Therefore, our data do not support delaying elective CABG surgery in the presence of a recent stroke," they write in Anesthesiology.
The team's study involved 62,104 patients identified in the Hospital Episode Statistics database from April 2006 through March 2010. In all, 695 (1.1%) patients had stroke in the previous 10 years, and, compared with those without stroke, these patients were 2.20-fold more likely to die, 1.99-fold more likely to have postoperative stroke, and 1.31-fold more likely to have a long hospital stay.
The time since stroke did not relate to postoperative outcomes, whether analyzed as a continuous variable or dichotomized at 6 or 3 months before surgery. However, the researchers caution that only a few operations involved patients with stroke in the previous 6 and 3 months (84 and 28 patients, respectively), "possibly due to the clinical perception of increased risk."
The association between prior stroke and outcomes was particularly marked in patients who also had previous myocardial infarction (MI). MI itself had no significant effect on outcomes, but the risk associated with MI plus stroke "far outweighed the risk of either condition individually," say Sanders et al.
The combination of previous MI and stroke raised mortality risk 5.54-fold and postoperative stroke risk 5.02-fold.
"This may be due to an interaction between hemodynamic compromise and embolic injury of the brain," the researchers suggest. They add: "This interaction may be overlooked, both clinically and by current scoring systems, and highlights the potential risk of the combination of cardiac and cerebral infarction."
Older age, heart failure, and liver disease also raised mortality risk in patients with prior stroke.
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