Risk of Stroke After Surgery 

Stroke is a relatively rare but debilitating consequence of surgery [1]. Albeit more common after cardiac surgery, patients who have undergone non-cardiac procedures are also at risk of experiencing stroke [2]. With stroke affecting functions such as vision, movement, and cognitive ability, not to mention carrying the risk of death, the importance of understanding the incidence of stroke after surgery and how best one can prevent it is evident [3]. 

Decades of research have revealed common risk factors that may increase a patient’s chance of experiencing stroke after both cardiac and non-cardiac surgery [4]. These factors include old age; female sex; and history of neurological disorders like migraine [4]. Modifiable risk factors include timing of surgery after a previous stroke; intraoperative poor systemic oxygenation; and intraoperative hypertension [4]. By making informed decisions concerning these latter factors, practitioners may be able to reduce their patients’ likelihood of stroke after surgery.   

Despite these commonalities, patients who receive cardiac surgery nevertheless have a higher chance of suffering from a postoperative stroke [4]. Fortunately, stroke following cardiac surgery is a well-researched phenomenon, so medical professionals have a great deal of instruction to rely on when treating cardiac surgery patients.  

Researchers have noted what characteristics make patients undergoing surgical aortic valve replacement (AVR) and coronary surgery more likely to suffer a stroke [5, 6]. In the AVR context, Idrees and colleagues noted the association between a patient’s heightened risk of postoperative stroke and comorbidities such as prior heart failure, carotid stenosis, endocarditis, hypercoagulation, and neurologic dysfunction [5]. Meanwhile, in cases of coronary surgery, Biancari et al.’s research suggested that severe bleeding requiring blood transfusion is associated with a heightened risk of stroke after surgery [6]. The extent to which these risk factors overlap across various types of cardiac operations is unclear.  

Additional evidence has emerged recently identifying genetic polymorphisms that may also heighten the risk of stroke following cardiac surgery [1]. By analyzing the genetics of 1,635 patients, among which twenty-eight postoperative strokes occurred following cardiopulmonary bypass surgery, Grocott and colleagues identified a significant association between common genetic variants of C-reactive protein and postoperative stroke [1]. This finding was not only compelling for screening purposes; it also indicated that inflammation may play an important role in stroke after cardiac surgery, given the link between the polymorphisms identified and patients’ predisposition for inflammation [1]. 

As for non-cardiac surgery, researchers have identified various other risk factors for stroke. For instance, intraoperative and routine use of preoperative metoprolol is associated with an increased risk of stroke after noncardiac surgery [2]. Current tobacco use, body mass index of 35-40 kg/m², and dialysis are also risk factors that may apply as well [7]. 

By keeping these associations in mind, medical professionals can better understand a particular patient’s unique risk of experiencing a stroke. This knowledge may inform what preventive measures a provider takes, such as administering oral anticoagulants or strictly controlling the patient’s blood pressure, two suggestions raised in the cardiac surgery context [8]. While preventive measures may never reduce the risk of stroke to zero, they nevertheless help decrease the likelihood that a patient will experience a debilitating and possibly deadly stroke after surgery. 

References 

[1] H. P. Grocott et al., “Genetic Polymorphisms and the Risk of Stroke After Cardiac Surgery,” Stroke, vol. 36, pp. 1854-1858, July 2005. [Online]. Available: https://doi.org/10.1161/01.STR.0000177482.23478.dc.  

[2] G. A. Mashour et al., “Perioperative Metoprolol and Risk of Stroke after Noncardiac Surgery,” Anesthesiology, vol. 119, pp. 1340-1346, December 2013. [Online]. Available: https://doi.org/10.1097/ALN.0b013e318295a25f.  

[3] “Effects of Stroke,” Johns Hopkins Medicine. [Online]. Available: https://www.hopkinsmedicine.org/health/conditions-and-diseases/stroke/effects-of-stroke.  

[4] S. Ko, “Perioperative stroke: physiology and management,” Korean Journal of Anesthesiology, vol. 71, no. 1, pp. 3-11, February 2018. [Online]. Available: https://doi.org/10.4097%2Fkjae.2018.71.1.3.  

[5] J. J. Idrees et al., “Trends, Predictors, and Outcomes of Stroke After Surgical Aortic Valve Replacement in the United States,” The Annals of Thoracic Surgery, vol. 101, no. 3, pp. 927-935, March 2016. [Online]. Available: https://doi.org/10.1016/j.athoracsur.2015.08.024.  

[6] F. Biancari et al., “Bleeding, transfusion and the risk of stroke after coronary surgery: A prospective cohort study of 2357 patients,” International Journal of Surgery, vol. 32, pp. 50-57, August 2016. [Online]. Available: https://doi.org/10.1016/j.ijsu.2016.06.032.  

[7] G. A. Mashour, A. M. Shanks, and S. Kheterpal, “Perioperative Stroke and Associated Mortality after Noncardiac, Nonneurologic Surgery,” Anesthesiology, vol. 114, pp. 1289-1296, July 2011. [Online]. Available: https://doi.org/10.1097/ALN.0b013e318216e7f4.  

[8] C. Isabel, D. Calvet, and J. Mas, “Stroke prevention,” La Presse Médicale, vol. 45, no. 12, pp. e457-e471, December 2016. [Online]. Available: https://doi.org/10.1016/j.lpm.2016.10.009.