The risk of perioperative stroke varies dramatically based on the intervention being performed. Stroke risk is generally estimated to be < 1% for cardiac catheterization, general surgery, and noncarotid vascular surgery. Carotid artery interventions, intracranial vascular procedures, and cardiac surgeries have higher rates of periprocedural stroke. Among cardiac surgeries, coronary artery bypass grafting (CABG) has been associated with a 1%–4% risk of stroke. Cardiac valve procedures and thoracic aortic surgeries have even higher risks, with estimates ranging from 2% to over 10% in some studies.
There are no existing guidelines for preoperative neurologic clearance. Studies, predominately conducted in cardiac surgery populations, have identified patient level risk factors for periprocedural stroke including age, a history of atherosclerotic risk factors and/or atherosclerotic disease, and a history of prior stroke. Additionally, there is evidence that the risk of periprocedural stroke is highest in the first 6 months after a prior stroke. Given the association between carotid stenosis and risk of stroke, a common and controversial clinical question is whether or not carotid artery imaging is necessary preoperatively.
Because symptomatic carotid artery stenosis is associated with a high short-term risk of stroke, patients should be screened to determine if they have a history of stroke, transient ischemic attack (TIA), or retinal ischemia within the past 6 months. If so, carotid imaging should be performed if not already done.
In patients with symptomatic carotid stenosis > 50% the risk of stroke recurrence is substantial, and it is appropriate to pursue carotid revascularization with carotid endarterectomy (CEA) or carotid artery stenting (CAS) prior to planned surgery.
In patients with stroke within the past 6 months without carotid stenosis, there appears to be an elevated risk of perioperative stroke, regardless of the stroke mechanism. This is true even in otherwise low-risk, noncardiac surgeries. If the surgery is not urgent, it is reasonable to delay the planned surgery until at least 6 months poststroke.
Among asymptomatic patients (no stroke or TIA within the past 6 months), the utility of carotid imaging depends on the planned surgery. Noncardiac surgery is associated with a low risk of stroke even in the presence of carotid stenosis; this perioperative stroke risk is generally exceeded by the risk of stroke complicating CEA or CAS. Given this, there is no need for carotid imaging prior to the planned procedure in asymptomatic patients.
For patients undergoing nonurgent CABG or other cardiac surgery requiring cardiopulmonary bypass, it is reasonable to perform screening carotid ultrasound on high-risk patients. High-risk features include age ≥ 70 years, prior stroke, multivessel coronary artery disease, peripheral artery disease, and the presence of a carotid bruit.
The presence of no stenosis or unilateral stenosis, or bilateral moderate stenosis is not associated with a significantly increased risk of stroke after CABG. Carotid intervention is not necessary prior to the planned cardiac surgery in these patients.
When bilateral severe stenosis/occlusion is present, consider revascularization of the more severely stenotic vessel, or the dominant hemisphere if both hemispheres are equally stenotic. Revascularization should not be attempted on an occluded vessel. When carotid revascularization is pursued, treatment strategies could include staged CAS/CABG, staged CEA/CABG, or combined CEA/CABG. In patients who do not require urgent coronary revascularization, staged CAS/CABG is likely optimal, given increased cardiac risk associated with CEA, but typically requires a delay in CABG of 4–6 weeks due to the need for short-term dual antiplatelet therapy. Similar decision-making likely applies to non-CABG cardiac surgery, although this is less well studied.