**6. Comment**

**Figure 5.** CT finding of distal arch aneurysm of thoracic aorta

390 Principles and Practice of Cardiothoracic Surgery

**Figure 6.** CT finding of repaired arch with a sealed quadrifurcated Dacron graft

#### **6.1. Moderate hypothermia**

Historically, total arch replacement has required deep hypothermic circulatory arrest (DHCA) or retrograde cerebral perfusion with DHCA during distal anastomosis.[1,2] However, these techniques do not give the surgeon adequate time to complete the aortic arch repair. The SCP technique, which extends the safe limits of time for arch surgery, has now gained acceptance.[4,5,6] As reliable SCP allows a high temperature setting during distal anastomosis, we have begun to use more moderate levels of hypothermia based on a tympanic temperature of 25-28℃. Core temperature based on bladder or rectal tempera‐ ture has generally been used as the minimum setting and the safety of using tympanic temperature as the minimum setting is controversial. Ehrlich and coworkers [7] showed that brain oxygen consumption is reduced to 50% of baseline values if the patient is cooled systemically to a core temperature of 28C, while Zierer and coworkers [6] showed that SCP in combination with mild hypothermia (core temperature of 30C) offers sufficient cerebral protection and may be safely applied to aortic arch surgery requiring SCP time of up to 90 minutes or more. Our minimum temperature setting is tympanic temperature of 25-28℃. In almost all cases, when the tympanic temperature reaches 25℃, which takes approximately 10-20 minutes, the core temperature is still at 30-32℃. Our clinical outcomes show a low incidence of neurologic deficits and suggested that the application of this perfusion and temperature management protocol to aortic arch surgery was safe.

#### **6.2. Sequence of reconstruction procedure**

After completion of distal anastomosis, CPB was restarted from the side branch of the graft and rewarming initiated immediately. This early rewarming protocol with SCP is also controversial. Okada, who also used the INVOS system for monitoring brain oxygenation and increased SCP flow to maintain the INVOS index at preoperative values, reported that early rewarming can minimize CPB time, but that monitoring of brain oxygenation during rewarm‐ ing is particularly important. [8]

After restart of CBP and rewarming, the proximal anastomosis is performed next and coronary perfusion restarted. Infusion of cardioplegic solution is thus needed only once. During arch vessel reconstruction, the heart-beat and progress of rewarming were sufficient to allow weaning from CPB, so that CPB could be discontinued immediately after reconstruction of the brachiocephalic artery. This sequence of reconstruction procedures minimizes CPB time and coronary ischemic time.

Recently, a number of studies have reported the safety of SCP with mild-moderate hypother‐ mia for protection of the brain and visceral organs. In the present chater, the excellent surgical results also indicate the safety of SCP under mild hypothermia.


[3] Hagl, C, Ergin, M. A, Galla, J. D, et al. Neurologic putcome after ascending aorta-aortic arch operations; effect of brain protection technique in high-risk patients. J Thorac

Fast – Track Total Arch Replacement http://dx.doi.org/10.5772/53600 393

[4] Kamiya, H, Hagl, C, Kropivnitskaya, I, et al. The safety of moderate hypothermic lower body arrest with selective cerebral perfusion: A propensity score analysis. J Thorac

[5] Minatoya, K, Ogino, H, Matsuda, H, et al. Evolving selective cerebral perfusion for aortic arch replacement : High flow rate with moderate hypothermic circulatory arrest.

[6] Zierer, A, Detho, F, Dzemali, O, et al. Antegrade Cerebral perfusion with mild hypo‐ thermia for aortic arxh replacement: Single center experience in 245 consecutive

[7] Ehrlich, M. P, Mccullough, J. N, Zhang, N, et al. Effect of hypothermia on cerebral blood

[8] Olsson, C, & Thelin, S. Resional cerebral saturation monitoring with near-infraed spectroscopy during selective antegrade cerebral perfusion: Diagnostic performance and relationship to postoperative stroke. J Thorac Cardiovasc Surg (2006). , 131, 371-79.

flow and metabolism in the pig. Ann Thorac Surg (2002). , 73, 191-7.

Cardiovasc Surg (2001). , 121, 1107-21.

Cardiovasc Surg (2007). , 133, 501-509.

Ann Thorac Surg (2008). , 86, 1827-32.

patients. Ann Thorac Surg (2011). , 91, 1868-74.

CPB = cardiopulmonary bypass

\*Requiring prolonged ventilation support of more than 48 hours

ICU = intensive care unit

**Table 1.** Operative and Postoperative Data
