A paper recently published in JAHA—Journal of the American Heart Association and co-authored by Creyos Neuroscientist Sydni Paleczny and CSO Professor Adrian Owen OBE, FRS, PhD, together with researchers from Sunnybrook Health Sciences Centre, reviewed the past 20 years of randomized controlled trials of coronary artery bypass graft (CABG) surgery. The study found that only 3% of trials included any cognitive testing, and further, the tools that were used are not sensitive enough to detect change.
Cognition is commonly impacted after cardiac surgery, but there remains a gap in care—objective, accessible, and accurate postoperative measurement still isn’t standard in cardiology research or postoperative clinical practice.
Here lies the opportunity. With objective cognitive testing, providers can improve how they assess brain health in post-surgery settings so that research can better capture what patients experience. If affected cognition is part of the patient experience, then it should be a part of the evidence collected.
Cognitive Decline After Coronary Artery Bypass Graft Surgery
Cognitive decline is common after coronary artery bypass graft (CABG) procedures, with 40% of individuals being affected postop, and can affect patient rehospitalizations, mortality, and quality of life.
CABG surgery is one of the most common major surgical procedures, with around 400,000 operations being performed in the United States annually. Cognitive impairment can be a common experience for people requiring coronary artery bypass (pre-surgically) as well, with 35% of individuals experiencing cognitive impairment before the procedure.
This may be because cognitive deficits are more common among older people, who are the primary demographic experiencing coronary heart disease (CHD). However, CHD itself is also a major risk factor for cognitive decline, and research suggests that cognitive impairment secondary to cardiac disease could be related to several mechanisms, like reduced blood flow and increased inflammation.
These observed cognitive deficits are primarily characterized by difficulties with attention, memory, executive function, and processing speed, and the time of postoperative onset and trajectory of these effects may vary.
It is also important to note that there is a high frequency of delirium or worsening cognition reported during the few weeks following the operation.
New Research into The Brain–Heart Connection
A newly published study titled "Cognitive Outcomes in Randomized Controlled Trials of Coronary Artery Bypass Graft Surgery From 2005 to 2025: A Systematic Review" takes a deep dive into how cognition is currently assessed after coronary artery bypass graft surgery, if at all, and identifies areas of improvement for cognitive testing methods to adequately provide critical insights into patient health postoperatively.
The Study
This study systematically reviewed randomized controlled trials (RCTs) of CABG surgery occurring between January 2005 and February 2025 to characterize whether cognition was evaluated, what assessment tools were used, and their effectiveness at detecting change. The team summarized the cognitive tasks used, testing frequency, domains assessed, and patient attrition.
It was found that of 3494 screened studies, 2284 were CABG RCTs, and only 71 of them (3.1%) reported any cognitive assessment of patients postoperatively. These 71 eligible studies collectively included 15,925 participants. From the articles that provided usable data, none of the assessment tools used were able to detect differences between pre- and postoperative cognitive performance among patients.
Overall, the findings indicate that cognitive assessment remains uncommon in CABG trials, and when it is accounted for, the chosen tests often fail to detect change. While previous combined analyses found impairment before and after surgery, the subtle change between these points is not being picked up in specific studies.
This may be because traditional cognitive screening and domain‐specific measures used previously, like the MoCA, may not be sensitive enough to accurately flag subtle deficits or mild cognitive impairment that otherwise remains undetected.
Objective Cognitive Assessment: A New Opportunity.
Cognitive testing has the potential to provide important health insights regarding cardiac patients’ brain health—though alternative approaches to standardized cognitive assessment in CABG patients or cardiovascular RCTs may be needed. While traditional dementia screening tests, like the Mini‐Mental State Examination (MMSE) or the Montreal Cognitive Assessment (MoCA), are quick and easy to administer, they have limitations.
Digital cognitive testing provides an alternative to these traditional dementia screening tests while providing accurate and detailed results. Creyos cognitive tests are precise, easy to administer, and provide valuable longitudinal data without interrupting patient workflows.
This review paper brings to light several key attributes of effective cognitive testing, including availability in multiple languages, standardization for administration without requiring trained psychometrists, the capability to detect changes between baseline and postoperative assessments, and lower vulnerability to attrition.
It also points to cognitive testing’s reflectivity of key cognitive domains (like memory and executive function) and patient-oriented outcomes like quality of life and time- and cost-effectiveness. To be feasible for widespread clinical and research implementation, outcomes should ideally fulfill as many of these criteria as possible.
Tests from Creyos are scientifically validated, leveraging a normative database of over 85,000 participants. Providers can assess patients confidently knowing that the tools they are using are backed by decades of scientific research. The Creyos tests are also available in multiple languages, gamified for higher patient engagement, and quick to administer.
These tests do not require additional training and can be administered remotely to promote accessibility. Importantly, research has demonstrated that the Creyos tests have high sensitivity and can detect meaningful cognitive changes in healthy and clinical populations. In cardiology settings, implementing the battery was found to be a feasible way of obtaining important insights about patients’ brain health. Each cognitive task is based on traditional assessments and has been shown to assess the domains intended, as evidenced by imaging research.
The Creyos tasks collectively measure the following domains of cognitive ability:
- Short-term memory
- Reasoning
- Concentration
- Verbal ability
Creyos assessments quickly gather cognitive insights with tasks that can be performed quickly and flexibly through both remote and in-person administration. Digital cognitive assessments from Creyos give you objective, domain-specific information efficiently and without interrupting workflows.
Reviewed by Sydni Paleczny, Staff Scientist
Sydni earned her MSc in Neurosciences at Western University under Dr. Adrian Owen. Her research explores neuropsychological outcomes after cardiac surgery, with interests in cognitive neuroscience, critical care, and brain health. At Creyos, she supports scientific validity, health technology, and ongoing research.