The importance...

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.

Hang on...

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

• NeuroVISION Investigators.
• Lancet. 2019 Sep 21; 394 (10203): 1022-1029.

BackgroundIn non-surgical settings, covert stroke is more common than overt stroke and is associated with cognitive decline. Although overt stroke occurs in less than 1% of adults after non-cardiac surgery and is associated with substantial morbidity, we know little about perioperative covert stroke. Therefore, our primary aim was to investigate the relationship between perioperative covert stroke (ie, an acute brain infarct detected on an MRI after non-cardiac surgery in a patient with no clinical stroke symptoms) and cognitive decline 1 year after surgery.MethodsNeuroVISION was a prospective cohort study done in 12 academic centres in nine countries, in which we assessed patients aged 65 years or older who underwent inpatient, elective, non-cardiac surgery and had brain MRI after surgery. Two independent neuroradiology experts, masked to clinical data, assessed each MRI for acute brain infarction. Using multivariable regression, we explored the association between covert stroke and the primary outcome of cognitive decline, defined as a decrease of 2 points or more on the Montreal Cognitive Assessment from preoperative baseline to 1-year follow-up. Patients, health-care providers, and outcome adjudicators were masked to MRI results.FindingsBetween March 24, 2014, and July 21, 2017, of 1114 participants recruited to the study, 78 (7%; 95% CI 6-9) had a perioperative covert stroke. Among the patients who completed the 1-year follow-up, cognitive decline 1 year after surgery occurred in 29 (42%) of 69 participants who had a perioperative covert stroke and in 274 (29%) of 932 participants who did not have a perioperative covert stroke (adjusted odds ratio 1·98, 95% CI 1·22-3·20, absolute risk increase 13%; p=0·0055). Covert stroke was also associated with an increased risk of perioperative delirium (hazard ratio [HR] 2·24, 95% CI 1·06-4·73, absolute risk increase 6%; p=0·030) and overt stroke or transient ischaemic attack at 1-year follow-up (HR 4·13, 1·14-14·99, absolute risk increase 3%; p=0·019).InterpretationPerioperative covert stroke is associated with an increased risk of cognitive decline 1 year after non-cardiac surgery, and perioperative covert stroke occurred in one in 14 patients aged 65 years and older undergoing non-cardiac surgery. Research is needed to establish prevention and management strategies for perioperative covert stroke.FundingCanadian Institutes of Health Research; The Ontario Strategy for Patient Oriented Research support unit; The Ontario Ministry of Health and Long-Term Care; Health and Medical Research Fund, Government of the Hong Kong Special Administrative Region, China; and The Neurological Foundation of New Zealand.Copyright © 2019 Elsevier Ltd. All rights reserved.

This article appears in the collection: Perioperative stroke.

21 keywords...

hide…