Transcatheter aortic valve replacement is associated with cognitive improvement in certain patients but cognitive impairment in others.
Researchers conducted a prospective cohort study of 229 consecutive patients aged at least 70 years (mean, 83 years) with symptomatic severe aortic stenosis who underwent TAVR at Bern University Hospital, Switzerland, from September 2009 to 2012. Eligible participants underwent thorough cardiological and geriatric baseline assessment, including cognitive testing using the mini-mental state examination (MMSE).
The researchers defined a global MMSE score of at least 26 points as normal, and a score of less than 26 was defined as impaired. Baseline testing was performed no more than 3 months before TAVR, and follow-up cognitive testing was generally conducted between 6 and 9 months after TAVR, with a maximum range of day 160 to day 300 after TAVR. Cognitive decline or improvement was specified as an increase or decrease of at least three points in the MMSE score between baseline and follow-up.
For patients who exhibited major cognitive decline or improvement between baseline and follow-up, the researchers sought to determine the potential reasons for these changes by reviewing these individual patients’ medical records.
The researchers found that, in the overall study population, there were no changes in the median MMSE global score between baseline (median, 27 points; interquartile range, 2; range, 15-30) and follow-up (median, 27 points; interquartile range, 3; range, 16-30; P = .59).
However, individual patient variations were common. Twenty-nine of 229 patients (12.7%) in the study population showed relevant MMSE score deterioration. In the 48 patients whose cognitive function was impaired at baseline, 18 patients (37.5%) exhibited cognitive improvements and six (12.5%) showed further deterioration.
Among the patients who survived to 6 months, baseline characteristics did not significantly differ between those who did not show cognitive deterioration and those who did. Patients who showed cognitive improvements had lower baseline aortic valve area vs. the baseline aortic valve area of patients who did not show cognitive improvements at 6 months (median, 0.6 cm2 vs. 0.8 cm2; P = .01). However, no statistically significant variations were seen in the other baseline measures.
Medical record review revealed eight (27.6%) of the 29 patients with at least a three-point decrease in global MMSE score had a major decline of at least five points. In six (75%) of these patients, a presumed cause of the cognitive decline was found. Two patients had postprocedural delirium after TAVR, one had a postprocedural cerebral embolic event, one had progressive renal failure after intervention, one had symptomatic HF and one patient was affected by pre-existing cerebrovascular disease and mild baseline cognitive impairment. Nine patients demonstrated an increase of five or more points on MMSE. Of these patients, none had a postinterventional complication.
“The present study, in conclusion, revealed that individual cognitive function varies considerably after [TAVR],” the researchers wrote. “It also showed that cognitive deterioration is often caused by postinterventional complications; delirium, in particular, seems to play an important role. Furthermore, this study suggests that a relevant proportion of patients with impaired baseline cognition have good prospects to improve owing to [TAVR]. Therefore, [TAVR] should not be withheld in patients with impaired preprocedural cognition.” – by Jennifer Byrne
Disclosure: The researchers report no relevant financial disclosures.