Among older adults undergoing coronary revascularization, the type of procedure performed (coronary artery bypass grafting [CABG] vs percutaneous coronary intervention [PCI]) has not demonstrated an effect on the rate of memory decline, according to a study recently published in the Journal of the American College of Cardiology.
The authors of this retrospective cohort study wrote that their investigation is important because “[i]t is uncertain whether [CABG] is associated with cognitive decline in older adults compared with a nonsurgical method of coronary revascularization (PCI).” The study objective was to compare the change in the rate of memory decline after PCI vs CABG.
The investigation included 1680 participants (41% women) in the Health and Retirement Study who underwent PCI or CABG between 1998 and 2015. The participants were aged ≥65 years (mean age at the time of procedure, 75 years). Medicare fee-for-service billing records were used to ascertain cardiac procedure type. A total of 665 underwent CABG and 1015 were treated with PCI. In the CABG group, 168 patients underwent off-pump procedures. The primary outcome was a composite memory score (derived from cognitive test scores and proxy cognition reports obtained biennially in the Health and Retirement Study) normalized to a z-score (mean of 0). The secondary outcome was the probability of developing dementia (a composite of the Telephone Interview for Cognitive Status, memory score, and serial-7 subtractions). To minimize the influence of atypically long preprocedural or postprocedural data periods, modeling for these outcomes was limited to 5 years preprocedure to 10 years postprocedure. Multivariable linear mixed-effects modeling was used to analyze memory score with further analysis of on-pump vs off-pump CABG. A change of 1 SD of memory decline (0.048 memory units/year) was designated as the minimum for clinical importance.
Among those who underwent PCI, memory declined at a mean rate of 0.064 memory units/year (95% CI, 0.052-0.078) preprocedure and 0.060 memory units/year (95% CI, 0.048-0.071) postprocedure, resulting in a within-group change of 0.004 memory units/year (95% CI, −0.010 to 0.018). Among those undergoing CABG, the preprocedural rate of memory decline was 0.049 memory units/year (95% CI, 0.033-0.065) and the postprocedural rate was 0.059 memory units/year (95% CI, 0.047-0.072), for a within-group change of −0.011 memory units/year (95% CI, −0.029 to 0.008). This resulted in a between-group difference of 0.015 memory units/year (PCI vs CABG; 95% CI, −0.008 to 0.038; P =.21). The rate of memory decline increased significantly following off-pump CABG vs PCI (0.046 memory units/year; 95% CI, 0.008-0.084; P <.05). However, there was no statistically significant increase after on-pump CABG vs PCI (0.003 memory units/year; 95% CI, −0.024 to 0.031).
These results are limited by the study’s inclusion of individuals who both decline and improve, uncertain clinical relevance of the brief neuropsychologic assessments incorporated in the Health and Retirement Study, the inclusion of only those receiving fee-for-service care, a lack of data on potentially impactful confounding variables, a focus on surgical techniques that may have evolved since the study period, and a heavy weighting of the memory score toward memory function.
The study researchers concluded that “the type of revascularization procedure was not significantly associated with differences in the change of rate of memory decline” among older adults who underwent CABG or PCI coronary revascularization.
Whitlock EL, Diaz-Ramirez LG, Smith AK, et al. Association of coronary artery bypass grafting vs percutaneous coronary intervention with memory decline in older adults undergoing coronary revascularization. J Am Coll Cardiol. 2021;325(19):1955-1964. doi: 10.1001/jama.2021.5150