Stroke in Surgical Patients: A Narrative Review

Phillip E. Vlisides, M.D.; Laurel E. Moore, M.D.


Anesthesiology. 2021;134(3):480-492. 

In This Article

Risk Factors and Incidence

Identifying patients at risk for perioperative stroke requires determination-and recognition-of underlying risk factors. Given the relative rarity of overt perioperative stroke, risk factors have been largely identified from large-scale epidemiologic studies (Table 2). Older age and previous cerebrovascular disease history are among the most commonly and strongly identified risk factors. The presence of patent foramen ovale was recently identified as a risk factor at both 30 days and up to 2 yr after surgery.[7,30] For noncardiac, nonneurologic patients with limited risk factors, overt stroke risk is 0.1%.[4] For patients with five or more risk factors undergoing relatively low-risk procedures, stroke risk is 1.9%, on par with the risk of stroke after high-risk procedures such carotid endarterectomy.[31] In a similarly low surgical risk subset of patients over 65 yr, the incidence of covert (clinically unrecognized) stroke diagnosed by postoperative magnetic resonance imaging was 7%.[5] The Neurological Impact of Cerebrovascular Events in Non-Cardiac Surgery Patients Cohort Evaluation (NeuroVISION) study, in addition to demonstrating a surprisingly high incidence of covert stroke, also suggested that covert stroke may have long-term effects on cognition and risk for recurrent ischemic stroke.[5]

As risk factors have been identified and clarified over the years, prediction models have become available for characterizing perioperative stroke risk. A recent observational study compared the effectiveness of existing prediction models, largely based on cardiovascular risk stratification, for predicting perioperative stroke after noncardiac surgery.[11] Results demonstrated that the American College of Surgeons (Chicago, Illinois) surgical risk calculator[32] and Myocardial Infarction or Cardiac Arrest risk score[33] had the highest discriminative ability for perioperative stroke. The Myocardial Infarction or Cardiac Arrest risk score has the additional advantage of simplicity, incorporating only five patient factors while still offering excellent discrimination for stroke.[11] Stroke risk (%) was not reported in relation to specific scores or thresholds for the majority of these prediction tools. However, in general, patients with high cardiovascular risk based on these models are likely to have high stroke risk as well.

Overall, the Myocardial Infarction or Cardiac Arrest and American College of Surgeons surgical risk calculators serve as easily accessible tools for practicing anesthesiologists preparing high-risk patients for surgery. These models could be used to gauge the overall risk of cardiovascular and cerebrovascular events (i.e., via myocardial infarction or cardiac arrest or American College of Surgeons surgical risk calculators) alongside complementary models that provide quantitative estimates of stroke risk.[4] This risk assessment is an important message to convey, because high-risk patients are infrequently counseled regarding perioperative stroke risk.[34]