Do management strategies for coronary artery disease influence 6-year cognitive outcomes?

Abstract

Background: Previous uncontrolled studies have suggested that there is late cognitive decline after coronary artery bypass grafting that may be attributable to use of the cardiopulmonary bypass pump.

Methods: In this prospective, nonrandomized, longitudinal study, we compared cognitive outcomes after on-pump coronary artery bypass surgery (n = 152) with off-pump bypass surgery patients (n = 75); nonsurgical cardiac comparison subjects (n = 99); and 69 heart-healthy comparison (HHC) subjects. The primary outcome measure was change from baseline to 72 months in the following cognitive domains: verbal memory, visual memory, visuoconstruction, language, motor speed, psychomotor speed, attention, executive function, and a composite global score.

Results: There were no consistent differences in 72-month cognitive outcomes among the three groups with coronary artery disease (CAD). The CAD groups had lower baseline performance, and a greater degree of decline compared with HHC. The degree of change was small, with none of the groups having more than 0.5 SD decline. None of the groups was substantially worse at 72 months compared with baseline.

Conclusions: Compared with subjects with no vascular disease risk factors, the CAD patients had lower baseline cognitive performance and greater degrees of decline over 72 months, suggesting that in these patients, vascular disease may have an impact on cognitive performance. We found no significant differences in the long-term cognitive outcomes among patients with various CAD therapies, indicating that management strategy for CAD is not an important determinant of long-term cognitive outcomes.

Figure 1. Boxplots showing the median distribution of baseline z-scores for each cognitive domain by study group

Verbmem = verbal memory; vismem = visual memory; visuo = visuoconstruction; lang = language; motor = motor speed; psych = psychomotor speed; atten = attention; exec = executive function; global = global composite scores * These coronary artery disease groups have a difference in their baseline means compared to HHC that are statistically significant at alpha=.05. HHC = heart healthy controls; CABG = coronary artery bypass grafting; OPCAB = off-pump coronary artery bypass (3 patients did not complete baseline testing); NSCC = nonsurgical cardiac comparison group.

Figure 2. Distribution of longitudinal composite global score pattern for each study group

HHC = heart healthy controls; NSCC = nonsurgical cardiac comparisons; CABG = coronary artery bypass grafting; OPCAB = off-pump coronary artery bypass group.