The growth in procedural medicine has seen increasing numbers of older patients undergoing surgery, with significant concern for the unproven potential of surgery and anaesthesia to hasten cognitive decline. Perioperative stroke is a major adverse event with high mortality (32%) and morbidity (59%) with cognitive consequences.
The NeuroVISION investigators sought to quantify the burden of covert stroke, that is stroke without overt symptoms.
What did they do?
The researchers conducted a multi-center prospective cohort study of 1,114 patients ≥65 years having elective non-cardiac, non-intracranial, non-carotid surgery. All patients underwent post-operative MRI to identify cerebral infarction, and 1 year follow-up to quantify cognitive decline.
And they found?
7% of patients showed MRI features of covert stroke. Of these 42% demonstrated cognitive decline at 1 year, compared to 29% of those without covert stroke (OR CI 1.22-3.20). There were associations with delirium (HR CI 1.06-4.73) and symptomatic stroke or TIA (HR CI 1.14-14.99).
Thus covert stroke is relatively common in this cohort of patients, and is associated with cognitive decline. Notably there was no associated increase in non-neurological outcomes or death, nor association with anaesthetic technique.
Although covert stroke was associated with greater incidence of cognitive decline, the later was still common among non-stroke patients (almost 30%), and around 25% of all patients showed MRI evidence of old chronic infarcts. Additionally because there was no non-surgical control, it is difficult to implicate surgery and anaesthesia itself as a precipitant of the covert strokes (compared with the disease process requiring surgery, or comorbidity).
Perhaps the greater take-home is that in an elderly population with significant morbidity (64% HT, 44% smokers, 27% DM) both stroke (chronic, covert and overt) and cognitive decline are not uncommon.
And the big question
Are any of these stroke related outcomes actually modifiable perioperatively? To meaningfully improve perioperative outcomes, there must be an available improvement in anaesthetic technique, surgical technique or triaging, or postoperative care.
It is likely that the greatest impact is still to be made through primary health care and not perioperative interventions.summary
Randomized Controlled Trial Multicenter Study
Randomized Controlled Trial Multicenter Study Clinical Trial