Introduction: Aortic valve replacement (AVR) for calcific aortic stenosis (AS) is associated with high rates of perioperative clinical stroke and “silent” acute cerebral infarcts (SACI) in older adults. The goal of this study was to determine the impact of clinical stroke and acute infarcts on cognitive outcomes.
Methods: 129 elderly surgical AVR (age=74.7±6y) participants underwent perioperative evaluations by neurologists and post-surgical diffusion-weighted MRI during the first week post-op. Clinical assessments and MRI’s were reviewed by vascular neurologists, and participants were classified as having clinical stroke, SACI, or no stroke. Trained coders quantified all acute lesions on MRI (lesion number, lesion volume). Participants also completed cognitive testing at baseline, 4-6 weeks, and 1 year. The incidence of post-operative cognitive disorder (POCD) was identified using reliable change index scores calculated in reference to a comparison group of 154 nonsurgical participants with vascular disease.
Results: Surgical participants who had a perioperative clinical stroke (n=34) had the largest infarct volume and performed worse than participants with SACI (n=59) and those without stroke on cognitive testing at baseline and at 4-6 weeks post-surgery (p < .05 for all). Among participants who showed an acute infarct on postop MRI (i.e., clinical stroke + silent stroke, n = 93), total acute infarct volume but not infarct number was significantly correlated with cognitive outcomes at 4-6 weeks and 1 year (r > .27 for all). Surgical participants with POCD (12.2% at 4-6 weeks; 9.2% at 1 year) were older, more likely to have had a perioperative clinical stroke, and had more and larger acute infarcts on MRI than surgical participants without POCD (p <.05 for all).
Conclusions: Cognitive outcomes and POCD are significantly associated with perioperative clinical stroke and volume of acute infarct on MRI. However, surgical participants who demonstrate small, SACI show good cognitive outcomes that are comparable to participants without perioperative infarct. Low baseline cognitive function may be a risk marker for perioperative stroke and poor cognitive outcomes in the elderly.