Postperfusion syndrome
Encyclopedia
Postperfusion syndrome, also known as "pumphead" is a constellation of neurocognitive
impairments attributed to cardiopulmonary bypass (CPB) during cardiac surgery
. Symptoms of postperfusion syndrome are subtle and include defects associated with attention, concentration, short term memory, fine motor function, and speed of mental and motor responses. Studies have shown a high incidence of neurocognitive deficit soon after surgery, but the deficits are often transient with no permanent neurological impairment.
(NEJM), showed an increased incidence of cognitive decline after coronary artery bypass surgery
(CABG); both immediately (53 percent at discharge from hospital
) and over time (36 percent six weeks , 24 percent at six months, and 42 percent at five years). This study shows an association of neurocognitive decline with CABG, but does not show causation
; the study lacks a control group and is considered level II-3 evidence. Also, the statistical calculation of cognitive decline has been demonstrated as the least reliable due to practice effects, measurement error and the regression to the mean phenomena .
Subsequent studies have compared "on-pump" CABG to off-pump coronary artery bypass
(OPCAB)—essentially establishing controls to compare the incidence of neurocognitive decline in CABG with and without the use of CPB. A small study (60 patients total, 30 in each treatment arm) by Zamvar et al. demonstrated neurocognitive impairment at both 1 week and 10 weeks postoperatively. A larger study (281 patients total) by Van Dijk et al. showed CABG surgery without cardiopulmonary bypass improved cognitive outcomes 3 months after the procedure, but the effects were limited and became negligible at 12 months. Furthermore, the Van Dijk study showed 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. A study by Jenson et al. published in Circulation found no significant difference in the incidence of cognitive dysfunction 3 months after either OPCAB or conventional on-pump CABG.
Given the above evidence, there is high incidence of neurocognitive deficit post bypass surgery, but the deficits are transient with no permanent neurological impairment. Controlled "on-pump" versus "off-pump" cardiac surgery has only been studied in the setting of CABG and is not necessarily generalizable to other types of cardiac surgery. Recent advancements in transcatheter and percutaneous
valve replacement
may soon allow comparison of other types of cardiac surgery with and without CPB.
and Vice-President Dick Cheney
. The National Enquirer
speculated that Clinton experienced permanent debilitating brain damage; using the NEJM article discussed above to provide credibility to the claim.
Neurocognitive
Neurocognitive is a term used to describe cognitive functions closely linked to the function of particular areas, neural pathways, or cortical networks in the brain substrate layers of neurological matrix at the cellular molecular level...
impairments attributed to cardiopulmonary bypass (CPB) during cardiac surgery
Cardiac surgery
Cardiovascular surgery is surgery on the heart or great vessels performed by cardiac surgeons. Frequently, it is done to treat complications of ischemic heart disease , correct congenital heart disease, or treat valvular heart disease from various causes including endocarditis, rheumatic heart...
. Symptoms of postperfusion syndrome are subtle and include defects associated with attention, concentration, short term memory, fine motor function, and speed of mental and motor responses. Studies have shown a high incidence of neurocognitive deficit soon after surgery, but the deficits are often transient with no permanent neurological impairment.
Evidence for postperfusion syndrome
A study by Newman et al. at Duke University Medical Center published in the New England Journal of MedicineNew England Journal of Medicine
The New England Journal of Medicine is an English-language peer-reviewed medical journal published by the Massachusetts Medical Society. It describes itself as the oldest continuously published medical journal in the world.-History:...
(NEJM), showed an increased incidence of cognitive decline after coronary artery bypass surgery
Coronary artery bypass surgery
Coronary artery bypass surgery, also coronary artery bypass graft surgery, and colloquially heart bypass or bypass surgery is a surgical procedure performed to relieve angina and reduce the risk of death from coronary artery disease...
(CABG); both immediately (53 percent at discharge from hospital
Hospital
A hospital is a health care institution providing patient treatment by specialized staff and equipment. Hospitals often, but not always, provide for inpatient care or longer-term patient stays....
) and over time (36 percent six weeks , 24 percent at six months, and 42 percent at five years). This study shows an association of neurocognitive decline with CABG, but does not show causation
Correlation does not imply causation
"Correlation does not imply causation" is a phrase used in science and statistics to emphasize that correlation between two variables does not automatically imply that one causes the other "Correlation does not imply causation" (related to "ignoring a common cause" and questionable cause) is a...
; the study lacks a control group and is considered level II-3 evidence. Also, the statistical calculation of cognitive decline has been demonstrated as the least reliable due to practice effects, measurement error and the regression to the mean phenomena .
Subsequent studies have compared "on-pump" CABG to off-pump coronary artery bypass
Off-pump coronary artery bypass
Off-pump coronary artery bypass or "beating heart" surgery is a form of coronary artery bypass graft surgery performed without cardiopulmonary bypass as a treatment for coronary heart disease. During most bypass surgeries, the heart is stopped and a heart-lung machine takes over the work of the...
(OPCAB)—essentially establishing controls to compare the incidence of neurocognitive decline in CABG with and without the use of CPB. A small study (60 patients total, 30 in each treatment arm) by Zamvar et al. demonstrated neurocognitive impairment at both 1 week and 10 weeks postoperatively. A larger study (281 patients total) by Van Dijk et al. showed CABG surgery without cardiopulmonary bypass improved cognitive outcomes 3 months after the procedure, but the effects were limited and became negligible at 12 months. Furthermore, the Van Dijk study showed no difference between the on-pump and off-pump groups in quality of life, stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
rate, or all-cause mortality
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
at 3 and 12 months. A study by Jenson et al. published in Circulation found no significant difference in the incidence of cognitive dysfunction 3 months after either OPCAB or conventional on-pump CABG.
Given the above evidence, there is high incidence of neurocognitive deficit post bypass surgery, but the deficits are transient with no permanent neurological impairment. Controlled "on-pump" versus "off-pump" cardiac surgery has only been studied in the setting of CABG and is not necessarily generalizable to other types of cardiac surgery. Recent advancements in transcatheter and percutaneous
Percutaneous
In surgery, percutaneous pertains to any medical procedure where access to inner organs or other tissue is done via needle-puncture of the skin, rather than by using an "open" approach where inner organs or tissue are exposed .The percutaneous approach is commonly used in vascular procedures...
valve replacement
Valve replacement
Valve replacement surgery is the replacement of one or more of the heart valves with either an artificial heart valve or a bioprosthesis . It is an alternative to valve repair.There are four procedures:...
may soon allow comparison of other types of cardiac surgery with and without CPB.
Neurocognitive deficit as a consequence of vascular disease
A study by McKhann et al. compared the neurocognitive outcome of people with coronary artery disease (CAD) to heart-healthy controls (people with no cardiac risk factors). People with CAD were subdivided into treatment with CABG, OPCAB and non-surgical medical management. The three groups with CAD all performed significantly lower at baseline than the heart-healthy controls. All groups improved by 3 months, and there were minimal intrasubject changes from 3 to 12 months. No consistent difference between the CABG and off-pump patients was observed. The authors concluded patients with long-standing coronary artery disease have some degree of cognitive dysfunction secondary to cerebrovascular disease before surgery; 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. A related study by 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. This finding suggests that late cognitive decline after coronary artery bypass grafting previously reported by Newman et al. may not be specific to the use of cardiopulmonary bypass, but may also occur in patients with similar risk factors for cardiovascular and cerebrovascular disease.Proposed mechanism of injury
Physicians have theorized that the syndrome is caused by tiny debris and air bubbles (microemboli) that enter the brain via cardiopulmonary bypass. Surgeons attempt to minimize time spent on bypass to decrease postoperative deficits; studies have shown increased bypass time is associated with increased incidence and severity of postperfusion syndrome and mortality.Postperfusion syndrome in the press
Postperfusion syndrome has attracted some public notoriety following the coronary bypasses of former U.S. President Bill ClintonBill Clinton
William Jefferson "Bill" Clinton is an American politician who served as the 42nd President of the United States from 1993 to 2001. Inaugurated at age 46, he was the third-youngest president. He took office at the end of the Cold War, and was the first president of the baby boomer generation...
and Vice-President Dick Cheney
Dick Cheney
Richard Bruce "Dick" Cheney served as the 46th Vice President of the United States , under George W. Bush....
. The National Enquirer
The National Enquirer
The National Enquirer is an American supermarket tabloid now published by American Media Inc . Founded in 1926, the tabloid has gone through a variety of changes over the years....
speculated that Clinton experienced permanent debilitating brain damage; using the NEJM article discussed above to provide credibility to the claim.
See also
- Heparin-coated blood oxygenator
- Postoperative cognitive dysfunction
- Post-chemotherapy cognitive impairmentPost-chemotherapy cognitive impairmentPost-chemotherapy cognitive impairment describes the cognitive impairment that can result from chemotherapy treatment. Approximately 20–30% of people who undergo chemotherapy experience some level of post-chemotherapy cognitive impairment...
(aka "chemo brain")
Further reading
- Cardiac Surgery In The Adult Chapter 11D Organ Damage
External links
- Pump Head - Cognitive Impairment After Bypass Surgery and rebuttal Pump Head - Not a Problem After All? Richard N. Fogoros, M.D. articles at about.com
- Canadian study to test value of heart-lung machine during cardiac surgery