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Cognitive impairment in older adults after CV procedures may be uncommon
Intermediate- and long-term cognitive impairment may be uncommon after CV procedures among older adults, according to a systematic review published in the Annals of Internal Medicine.
Researchers analyzed data from 17 randomized controlled trials and four prospective cohort studies (mean age, 68 years; 80% men) that reported on cognitive outcomes at least 3 months after undergoing CABG, carotid revascularization or cardiac valve procedures among adults aged 65 years or older.
Howard A. Fink, MD, MPH, and colleagues found that in six studies comparing on- and off-pump CABG, three studies comparing hypothermic and normothermic CABG and one study comparing CABG with medical management, no significant differences between any of the groups were observed with regard to cognitive function.
In one study comparing minimal and conventional extracorporeal CABG, the minimal strategy was associated with reduced risk for incident cognitive impairment (risk ratio = 0.34; 95% CI, 0.16-0.73), according to the researchers.
Results from two trials comparing surgical carotid revascularization with carotid stenting or angioplasty indicated no difference in cognitive outcomes, Fink, from the Geriatric Research Education & Clinical Center, Veterans Affairs Health Care System, Minneapolis, and colleagues found.
In one cohort study, transcatheter aortic valve replacement was associated with increased cognitive decline compared with surgical AVR (28% vs. 6%; P = .041), but the researchers noted that the results may have been biased because patients in the TAVR group were older, less educated and had higher surgical risk. The study had other limitations, they wrote, including different definitions of cognitive decline and different batteries of tests administered. No significant within-group changes observed in any neuropsychological test were observed between baseline and 3 months.
In one cohort study comparing patients who underwent CABG alone with those who had surgical aortic or mitral valve replacement alone or combined with CABG, there were no differences between the groups in 6-month cognitive outcomes as indicated by 13 of 14 administered psychological tests, the researchers wrote.
Results from one trial comparing cognitive outcomes between hypothermic and normothermic surgical AVR indicated no between-group differences in cognitive outcomes at 4 months; however, no numerical data were provided, Fink and colleagues wrote.
In the 13 studies that reported incident stroke and transient ischemic attack, rates of stroke and TIA were low and there were no significant differences between groups in any study that reported stroke, TIA and cognitive outcomes, they wrote.
“Results suggest that persistent cognitive impairment after the studied [CV] procedures may be uncommon or reflect cognitive impairment that was present before the procedure,” Fink and colleagues wrote. “Physicians counseling older patients having the studied [CV] procedures should advise that although current data suggest cognitive risks may be small, there is substantial uncertainty about these estimates.” – by Erik Swain
Disclosure: The researchers report no relevant financial disclosures.
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There has always been concern about neurocognitive dysfunction after any type of major surgery, whether it be cardiac surgery or any other operations that require lots of anesthesia and take long periods of time. There is information going back many years regarding cognitive dysfunction after cardiac surgery. That’s why improvements in technology and new ways of using a heart-lung machine and screening for vascular disease of the brain, among other things, have become common in cardiac surgery. I am happy that this paper shows that the work that has been done over the past decade or more has actually improved outcomes. One of the great fears of coming out of a successful heart operation is that the brain might be damaged. This adds to the evidence that that is not happening to any appreciable degree in older patients.
One of my personal areas of research has been figuring out how to use the heart-lung machine in safer ways. Several years ago, I was involved in a major randomized study looking at new types of circuits and new types of pumps used in the heart-lung machine. We were able to show improvement in neurocognitive function after heart surgery compared with the older technology. In addition, as chief of cardiac surgery at UCLA, I am operating on university professors, athletes and other people who are extremely creative, and I focus on how they are able to get back to their life after major heart surgery when they make their living using their brains. So this is consistent with my experience being able to do these operations safely without impacting cognitive function.
It’s always good to work for more improvements and to consider cognitive dysfunction as one of the major outcomes. Now, as the population shifts, we are operating routinely on more people in their 80s and 90s. We have to make sure that we continue to advance our technologies and our techniques. I don’t think we will ever rest on our laurels. We can assure patients that they will continue to have good outcomes, but continued work to improve things is the way of the future. I would like to see continued improvements in the understanding of brain function, so monitoring the brain during the operation becomes more sophisticated. For example, in some types of operations that we perform, we do continuous electroencephalogram monitoring, and routinely assess the oxygen saturation to both sides of the brain throughout the operation. I don’t think that this has necessarily been adopted throughout the CV community. We need continued strong evidence that leads to higher standards of care across the nation, so that everyone has the very best in brain protection and cardiac protection no matter where they go to get their surgery.
I think this is an important study and am gratified to see the good results in patients. It hopefully will lead to more research and an increased standard of care across the nation in how we monitor the brain. Some patients who come to cardiac surgery have already had strokes or other neurological events. I’d like to see continued research in a more focused way on this higher-risk subset to see if we can duplicate these results for them.