The field of perfusion is becoming increasingly demanding both clinically and didactically. As the patient population continues to present with a variety of complex health issues, there is a greater need than ever for the Pefusionist to develop new techniques for patient care while on Cardiopulmonary Support. Ascending Aortic Arch dissections (AAAD), with its current mortality rates of 10%-15% with significant neurological complications associated, still remains a difficult case for Perfusionist’s to manage effectively. The most widely used technique during this type of repair surgery, is hypothermic circulatory arrest (HCA). Although this remains a premier technique, there continues to be a high reported incidence of neurological deficit post HCA. In order to address and limit this issue, the advent of selective cerebral perfusion is slowly gaining acceptance. This new technique has been shown to not only decrease the time of exposure of blood to a foreign surface, but limit the patient duration on full cardiopulmonary support. The most notable aspect of this technique; is it allows the surgeon to begin repairs immediately, since the process cools the brain only, while keeping the rest of body at moderate-mild hypothermic levels.

1. Neuroprotection using Selective Cerebral Perfusion
Karounka Keita-CCP/LP, Justin Savage CCP/LP, Bill Nicotra (Chief) CCP/LP
Medstar Healthcare Systems
Circuit DesignIntroduction
Background
Cannulation Sites
Discussion
References
1. Kazui, Inoue N. Yamada O, et al. Selective Cerebral Perfusion During Operations for
Aneurysms of the Aortic Arch:Reassessment. Ann Thoracic Surgery 1992:53109-114.
2. Bachet, Guilmet D, Goudot B. et al Cold Cerebroplegia. A new technique of cerebral
protection during operations on the transverse arch. J Thoraciic Cardiovascular Surgery
1991:102:85-94.
3. Randall B. Griepp, Eva B. Griepp. Perfusion and Cannulation strategies for neiurological
protection in aortic arch surgery. Ann Cardiothoracic Surgery 2013;2(2):159-162
4. Wypij D, Newburger JW, Rappaport LA, et al. The effect of duration of deep hypothermic
circulatory arrest in infant heart surgery on late neurodevelopment: the Boston Circulatory
Arrest Trial. J Thorac Cardiovasc Surg. 2003;126:1397–1403
5. Mahle WT, Cuadrado AR, Tam VK. Early experience with a modified Norwood procedure
using right ventricle to pulmonary artery conduit. Ann Thorac Surg. 2003;76:1084–1088.
6. Poirier NC, Drummond-Webb JJ, Hisamochi K, et al. Modified Norwood procedure with a
high-flow cardiopulmonary bypass strategy results in low mortality without late arch
obstruction. J Thorac Cardiovasc Surg. 2000;120:875–878
7. Pizarro C, Malec E, Maher KO, et al. Right ventricle to pulmonary artery conduit improves
outcome after stage I Norwood for hypoplastic left heart syndrome. Circulation. 2003 Sep
9;108 Suppl 1:II155–11160.
8. Andropoulos DB, Stayer SA, McKenzie ED, Fraser CD., Jr Novel cerebral physiologic
monitoring to guide low-flow cerebral perfusion during neonatal aortic arch reconstruction. J
Thorac Cardiovasc Surg. 2003;125:491–499.
9. Andropoulos DB, Stayer SA, McKenzie ED, Fraser CD., Jr Regional low-flow perfusion
provides comparable blood flow and oxygenation to both cerebral hemispheres during
neonatal aortic arch reconstruction. J Thorac Cardiovasc Surg. 2003;126:1712–1717.
Antegrade cerebral perfusion was first reported by Frist and colleagues in
1986 in combination with profound hypothermic circulatory arrest (PHCA). It
was later popularized independently by Bachet and Kazui and their
respective colleagues in the early 1990’s. Developed as a theoretical
advantage of protecting the brain from hypoxic ischemic injury; selective
antegrade cerebral perfusion (SACP) is used in lieu of deep hypothermic
circulatory arrest (DHCA) to provide adequate perfusion to the brain. The
potential benefits of this new type of technique began to generate interest
after the publication of data comprising of a 8 year Boston Circulatory Arrest
Study that demonstrated a “cut point” of 41 minutes of DHCA that existed;
beyond which neuro-developmental abnormalities became significantly
more prevalent (4). Because the median of DHCA times for the Norwood
Stage I palliation, for Hypoplastic Left Heart Syndrome (HLHS) in research
papers from 2000-2005 was 50 minutes (5,6,7), an additional theoretical
benefit of SACP is to provide the surgeon with adequate time to create and
complete an aortic reconstruction. This premise is validated by the reported
SACP times of 40–70 minutes in subsequent publications (8,9).
Furthermore, after seeing the success and decrease in neurological
complications post SACP procedures, many are now adopting this approach
for its simplicity and its ability to provide both cerebral and multi-organ
protection.
The field of perfusion is becoming increasingly demanding both clinically and
didactically. As the patient population continues to present with a variety of
complex health issues, there is a greater need than ever for the Pefusionist to
develop new techniques for patient care while on Cardiopulmonary Support.
Ascending Aortic Arch dissections (AAAD), with its current mortality rates of
10%-15% with significant neurological complications associated, still remains
a difficult case for Perfusionist’s to manage effectively. The most widely used
technique during this type of repair surgery, is hypothermic circulatory arrest
(HCA). Although this remains a premier technique, there continues to be a
high reported incidence of neurological deficit post HCA. In order to address
and limit this issue, the advent of selective cerebral perfusion is slowly gaining
acceptance. This new technique has been shown to not only decrease the
time of exposure of blood to a foreign surface, but limit the patient duration on
full cardiopulmonary support. The most notable aspect of this technique; is it
allows the surgeon to begin repairs immediately, since the process cools the
brain only, while keeping the rest of body at moderate-mild hypothermic
levels.
The goal of our study was to validate the effectiveness of Selective Antegrade
Cerebral Perfusion in cardiac surgical procedures by examining case studies
and scientific literature. We found advantages in decreased stroke rate, stable
auto regulation, and an overall decreased need for blood products. SACP
allows for full neuro-protection of the brain while maintaining a mild metabolic
state for the body. Circuit modifications are very little to achieve the technique.
In our extracorporeal circuit (as seen in above diagram), a Medtronic
cardioplegia delivery system is connected into the arterial line with a “Y”
connecter and temperature regulated with a separate heater cooler. Utilizing
this method, oxygenated blood can be delivered at mild temperatures to the
body and separately hypothermic to the brain through the head vessels. The
end results reflect in faster procedure times and positive patient outcomes.
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Conclusion
Selective antegrade cerebral perfusion (SACP) is a promising technique to be
utilized during cardiopulmonary bypass.There continues to be clinical data
supporting its use, in lieu of deep hypothermic circulatory arrest for aortic arch
reconstruction. In addition, SACP has now superseded retrograde cerebral
perfusion as a neuroprotective adjunct. Performed correctly, this method
overcomes many of the limitations associated with other forms of cerebral
perfusion. In the studies conducted at a variety of multicenters, they have
demonstrated that the duration of SACP (up to 90 min) and the extent of the
arch replacement were not associated with any increased risk of hospital
mortality or poorer neurological outcome. Thus, as stated again SACP greatly
extends the safe period of circulatory arrest when compared to DHCA alone
and is best used during complex and time consuming procedures. With the
use of SACP, the maintenance of cerebral blood flow allows for the
employment of moderate levels of hypothermia (26 C) instead of deep. This in
turn, results in a reduction in duration of extracorporeal circulation required to
cool and re-warm the patient. Conversely, this technique is technically more
complicate; the surgeon must be aware that care must be taken during
endoluminal positioning of the cannula’s into the arch vessels to prevent distal
dissection, or debridement of an atherosclerotic plaque.
Advantages
Decreased Stroke rate when compared to HCA and RCP.
Decrease blood product usage (secondary to bleed, associated with mild
hypothermia)
Decreased expense to the patient and hospital (secondarily to shorter
operating time)
Auto-regulation is not impaired
Finer tune control of temperature and perfusion