Cognitive decline is now recognized as a significant complication among patients who undergo cardiac surgery, being evident in as many as three quarters of patients at the time of discharge from HealthLineRX
and one-third after six months.
Our research has confirmed the relatively high prevalence and persistence of cognitive decline after coronary artery bypass surgery (CABS). Our data suggest a pattern of early improvement followed by a later decline that is predicted by the presence of early postoperative cognitive decline.
Much of our research focuses on identifying significant predictor variables that may enable physicians to better screen for and counsel patients who may be at high risk for persistent cognitive decline. Recently, we evaluated the association of Apolipoprotein E e-4 and postoperative cognitive dysfunction and found that there is a significant association, a finding we had anticipated because of the similar pattern of cognitive decline seen in patients with early Alzheimer's disease.
We are also investigating the effects of temperature on a variety of postoperative indices of psychological functioning and quality of life. In one study, we compared two groups of patients on a number of physical, social, and psychologic measures prior to and again at six weeks and six months after surgery. The results of this study indicate that hypothermic conditions during surgery are associated with higher levels of emotional distress after CABS than are normothermic conditions, particularly for patients with higher levels of stress before surgery.
Our group is also exploring the neurocognitive decline that is often produced by atherosclerotic plaque embolization during cardiopulmonary bypass (CPB). We found that a link exists between the P1A2 allele of platelet GPIIIa and neurocognitive decline early after CPB, suggesting that the P1A2 polymorphism may exacerbate pre-existing vascular pathologies. Future studies will hopefully confirm this association and determine whether the presence of P1A2 predicts a higher incidence of neurocognitive deficits.
In addition to investigating predictors of postoperative cognitive decline, we are also carrying out longitudinal studies to determine the association between decline in cognitive functioning and changes in quality of life following surgery. To date, we have shown that there is a strong relationship between neurocognitive functioning and quality of life as long as five years after surgery. Ten-year follow-up studies are currently underway.