Postperfusion syndrome, is a constellation of neurocognitive impairments attributed to cardiopulmonary bypass during cardiac surgery.
Symptoms of postperfusion syndrome: defects associated with attention, concentration, short-term memory, fine motor function, and speed of mental and motor responses.
There is a high incidence of neurocognitive deficit soon after surgery, but they are often transient with no permanent neurological impairment.
A study showed an increased incidence of cognitive decline after coronary artery bypass surgery (CABG), both immediately: 53 percent at discharge from hospital, 36 percent at six weeks, 24 percent at six months, and 42 percent at five years.
While there is an association of neurocognitive decline with CABG, it does not show causation.
Neurocognitive impairment is worse for the on-pump patients both 1 week and 10 weeks postoperatively.
CABG surgery without cardiopulmonary bypass improves cognitive outcomes 3 months after the procedure, but the effects were limited and became negligible at 12 months (Van Dijk study).
In the above study there was no difference between the on-pump and off-pump groups in quality of life, stroke rate, or all-cause mortality at 3 and 12 months.
Other studies found no significant difference in the incidence of cognitive dysfunction 3 months after either OPCAB or conventional on-pump CABG.
There is high incidence of neurocognitive deficit shortly after bypass surgery, but evidence is less clear about long-term neurological impairment.
Authors conclude patients with long-standing coronary artery disease have some degree of cognitive dysfunction secondary to cerebrovascular disease before surgery, and there is no evidence the cognitive test performance of bypass surgery patients differed from similar control groups with coronary artery disease over a 12-month follow-up period.
Selnes et al. concluded patients with coronary artery bypass grafting did not differ from a comparable nonsurgical control group with coronary artery disease 1 or 3 years after baseline examination.
The late cognitive decline after coronary artery bypass grafting may not be specific to the use of cardiopulmonary bypass, but may also occur in patients with very similar risk factors for cardiovascular and cerebrovascular disease.
It is Suggested that the syndrome is caused by tiny debris and air bubbles, or microemboli, that enter the brain via cardiopulmonary bypass.
Increased bypass time is associated with increased incidence and severity of postperfusion syndrome and mortality.
It remains unexplained how increases in bypass time would result in the increased incidence and severity of postperfusion syndrome and mortality, if pre-existing cardiovascular and cerebrovascular conditions are the principal causative mechanisms of postperfusion syndrome.