Simple hypothermic retrograde cerebral perfusion for brain protection during aortic arch surgery]

We have recently found that retrograde cerebral perfusion can be performed by simply elevating central venous pressure to 15 mmHg in the Trendelenburg position when the aortic arch is open during aortic arch surgery. During deep hypothermic (15 degrees C) perfusion of the lower half of the body with the descending aorta occluded, and with single cannulation of the right atrium for drainage, oxygen-saturated venous blood perfuses the brain retrogradely, supplying it with oxygen. This method renders clamping of the aortic arch and the arch vessels unnecessary. Eleven cases of aortic arch aneurysm (9 males, 2 females; 5 true aneurysms, 5 dissecting aneurysms, one combined aneurysm; mean age, 63 years) were operated using this technique, whose clinical significance was then evaluated. Median sternotomy was performed in 4 cases, left thoracotomy in 7. Patch replacement was performed in 2 cases and graft replacement in 9 cases (the proximal arch in 2, the whole arch in 2, the distal arch in 5). In two cases coronary artery bypass surgery using the internal thoracic artery was performed simultaneously via lateral thoracotomy. Operation time was 517 +/- 139 min, pump time was 211 +/- 34 min, cardiac arrest time was 84 +/- 34 min and the lowest rectal temperature was 15.7 +/- 1.1 degrees C. In the venous return, PO2 was 188 +/- 136 mmHg, and SO2 97.5 +/- 2.9%, the respective values in the retrogradely perfused blood in the aortic arch being 46 +/- 12 mmHg and 68.8 +/- 18.8%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Simple hypothermic retrograde cerebral perfusion during aortic arch replacement. A preliminary report on two successful cases.

We recently found that hypothermic retrograde cerebral perfusion can be performed by simply elevating the central venous pressure in Trendelenburg's position while the aortic arch is open. In this technique, with an occlusion balloon in the descending aorta, deep hypothermic perfusion of the lower half of the body is performed as oxygen-rich venous blood supplies the brain. Two successful cases are reported: one of dissecting aortic aneurysm, DeBakey type II, with a true aortic arch aneurysm, in a 53-year-old woman, and one of acute aortic dissection, DeBakey type I, in a 53-year-old man. With the brain under retrograde perfusion at a rectal temperature of 15 degrees C and a central venous pressure of 15 mm Hg, replacement of the ascending to the descending aorta in the former case and to the proximal aortic arch in the latter case was successful. Cerebral circulatory arrest times were 81 and 65 minutes, respectively. No neurologic deficit was found postoperatively. It is suggested that this simple technique protected the brain for a long period of cerebral circulatory arrest during the aortic arch operation by supplying it with oxygen and simplifying the operative procedure.     

Preliminary results of intermittent retrograde cerebral perfusion during proximal aortic arch surgery.

OBJECTIVE: Continuous retrograde cerebral perfusion during aortic arch surgery is associated with cerebral edema. In this report, we describe the clinical use of a new type of intermittent retrograde cerebral perfusion. SUBJECTS AND METHODS: Fourteen patients with a Stanford type A dissection were included in this study. With the usual method of retrograde cerebral perfusion, about 2,500 mL venous blood is drained from bicaval cannulae into a hard-shell reservoir, and oxygenated blood is perfused through the superior vena caval cannula. The flow rate is 300 mL/min. After about 15 min, retrograde perfusion is discontinued, and drainage from the bicaval cannulae is restarted. When a bloodless field is necessary, perfusion also is discontinued. RESULTS: Two to seven cycles of intermittent retrograde cerebral perfusion were administered (average, 3.1+/-0.4, mean+/-SD). The total retrograde perfusion time was 36.0+/-1.9 min which was equivalent to 74.8% of the circulatory arrest time. No patient developed edema of the upper body. The time to wake-up was 3 to 14 h (average, 6.5+/-1.0 h). No patient suffered any neurologic complications even though the time of circulatory arrest was greater than 60 min in four cases. Head magnetic resonance imaging or computed tomography was performed in 12 cases, and no evidence of hypoxic brain injury was detected. CONCLUSIONS: Our clinical experience using a moderate amount of intermittent retrograde cerebral perfusion is superior to continuous retrograde cerebral perfusion for protecting the brain during aortic arch surgery.     

Deep hypothermic systemic circulatory arrest and continuous retrograde cerebral perfusion for surgery of aortic arch aneurysm.

From 1987 to February 1991, we have repaired or replaced the aortic arch in ten patients using deep hypothermic systemic circulatory arrest with continuous retrograde cerebral perfusion (CRCP). CRCP can be implemented using the bypass connecting the arterial and venous lines of the extracorporeal circuit to reverse the flow into the superior vena cava cannula after induction of circulatory arrest. CRCP flow required to maintain an internal jugular vein pressure of 20 mmHg ranged from 100 to 500 ml/min. After completion of suturing of the aortic arch graft, air is evacuated retrogradely from the open arch vessels prior to reestablishing the usual arterial return. Two patients died, one from sepsis and the other from liver cirrhosis 1 month postoperatively. CRCP times ranged from 11 to 56 min, and minimal nasopharyngeal temperatures ranged from 16 degrees to 18 degrees C. The difference in oxygen content between the perfused blood and the blood draining from the arch vessels during CRCP most likely reflected the steady-state metabolism of the brain during the deep hypothermic state. This technique offers advantages including the need for dissecting and clamping the arch branches, providing sufficient metabolic support to the brain during deep hypothermia, and eliminating embolism of particulate debris from the aortic arch.     

Preliminary results of intermittent retrograde cerebral perfusion during proximal aortic arch surgery

Objective: Continuous retrograde cerebral perfusion during aortic arch surgery is associated with cerebral edema. In this report, we describe the clinical use of a new type of intermittent retrograde cerebral perfusion.Subjects and Methods: Fourteen patients with a Stanford type A dissection were included in this study. With the usual method of retrograde cerebral perfusion, about 2,500 mL venous blood is drained from bicaval cannulae into a hard-shell reservoir, and oxygenated blood is perfused through the superior vena caval cannula. The flow rate is 300 mL/min. After about 15 min, retrograde perfusion is discontinued, and drainage from the bicaval cannulae is restarted. When a bloodless field is necessary, perfusion also is discontinued.Results: Two to seven cycles of intermittent retrograde cerebral perfusion were administered (average, 3.1±0.4, mean±SD). The total retrograde perfusion time was 36.0±1.9 min which was equivalent to 74.8% of the circulatory arrest time. No patient developed edema of the upper body. The time to wake-up was 3 to 14 h (average, 6.5±1.0h). No patient suffered any neurologic complications even though the time of circulatory arrest was greater than 60 min in four cases. Head magnetic resonance imaging or computed tomography was performed in 12 cases, and no evidence of hypoxic brain injury was detected.Conclusions: Our clinical experience using a moderate amount of intermittent retrograde cerebral perfusion is superior to continuous retrograde cerebral perfusion for protecting the brain during aortic arch surgery.     

Influence of retrograde cerebral perfusion during aortic arch procedures

BACKGROUND: Recent reports suggest dramatic improvement in outcome using retrograde cerebral perfusion (RCP) during operations on the arch; however, most investigators have compared contemporary results with historic controls. The purpose of this study was to determine the impact of RCP within the same patient population and time period. METHODS: From 1996 to 2000, 72 consecutive patients underwent an aortic arch procedure using hypothermic circulatory arrest (HCA) (31 acute dissection or rupture, 41 chronic dissection or aneurysm). Supplemental RCP was used in 36 patients, whereas 36 patients had HCA alone. The groups were similar in age, emergent status, and cardiopulmonary bypass time (p > 0.08), but HCA time was higher with RCP (40 +/- 15 minutes versus 29 +/- 14 minutes; p < 0.001). RESULTS: Operative mortality was 10% +/- 4% (+/- 70% confidence limit), and adverse outcomes (death or cerebrovascular accident) occurred in 14% +/- 4%, but there was no difference between HCA alone (8% +/- 5%, 14% +/- 6%) and HCA with RCP (11% +/- 5%, 14% +/- 6%) (p > 0.73). The incidence of transient neurologic dysfunction was also similar (HCA alone, 11% +/- 5%; HCA with RCP, 17% +/- 6%; p > 0.73). Multivariate risk factors for mortality included emergency operation and HCA time (p < 0.02). Risk factors for adverse outcome included emergency operation and atheromatous ascending aorta (p < 0.03). Risk factors for transient neurologic dysfunction included preexisting cerebrovascular disease and rewarming retrograde (femoral) rather than antegrade (through the graft) (p < 0.03). CONCLUSIONS: Supplemental RCP during HCA did not decrease mortality or neurologic complications. Retrograde rewarming through the femoral artery after completion of the distal anastomosis increased transient neurologic dysfunction. Therefore, RCP remains optional, but reperfusion should be antegrade to improve neurologic recovery.     

Results of aortic arch repair with hypothermic circulatory arrest and retrograde cerebral perfusion

BACKGROUND: Repair of aortic arch pathology is reliably performed with hypothermic circulatory arrest, but the best method of brain protection is controversial. METHODS: We reviewed a consecutive series of 67 patients who had aortic arch repair with hypothermic circulatory arrest. Retrograde perfusion of arterial blood into the superior vena cava (SVC) during systemic arrest was used in 87%. Average age was 65 years. Acute dissection was present in 25%. Average circulatory arrest time was 37 minutes, and average temperature 17.7 degrees C. RESULTS: Hospital mortality was 1.5%. Strokes occurred in 4.5%. Temporary neurological dysfunction occurred in 16%. Multivariate logistic regression analysis showed that acute dissection was the only independent predictor of the combined risk of stroke and temporary neurological dysfunction (odds ratio 8.5). Duration of circulatory arrest and patient age were not risk factors for adverse neurological outcome. CONCLUSION: Continuous arterial perfusion of the SVC during hypothermic circulatory arrest provides excellent cerebral protection for aortic arch repair. Acute dissection is an independent risk factor for adverse neurological outcome. Arrest time is not a predictor of neurological dysfunction.     

The methodologies of hypothermic circulatory arrest and of antegrade and retrograde cerebral perfusion for aortic arch surgery

In spite of recent advances in thoracic aortic surgery, postoperative neurological injury still remains the main cause of mortality and morbidity after aortic arch operation. The use of cardiopulmonary bypass (CPB) and hypothermic circulatory arrest, temporary interruption of brain circulation, transient cerebral hypoperfusion, and manipulations on the frequently atheromatic aorta all produce neurological damages. The basic established techniques and perfusion strategies during aortic arch replacement number three: hypothermic circulatory arrest (HCA), antegrade cerebral perfusion (ACP), and retrograde cerebral perfusion (RCP). During the past decade and after several experimental studies, RCP lost its previous place in the armamentarium of brain protection, giving it up to ACP as a major method of brain perfusion during HCA. HCA should be applied at a temperature of asymptotically equal to 20 degrees C with long-lasting cooling and rewarming and should not exceed by itself the time of 20-25 min. RCP does not seem to prolong safe brain-ischemia time beyond 30 min, but it appears to enhance cerebral hypothermia by its massive concentration inside the brain vein sinuses. HCA combined with ACP, however, could prolong safe brain-ischemia time up to 80 min. Cold ACP at 10 degrees -13 degrees C should be initially applied through the right subclavian or axillary artery and continued bihemispherically through the left common carotid artery at first and later the anastomosed graft, with a mean perfusion pressure of 40-70 mm Hg. The safety of temporary perfusion is being confirmed by the meticulous monitoring of brain perfusion through internal jugular bulb O2 saturation, electroencephalogram, and transcranial comparative Doppler velocity of the middle cerebral arteries.     

Medium-term results after surgery for aortic arch aneurysm with hypothermic cerebral perfusion

We have used two techniques of hypothermic cerebral perfusion (CP) for the surgical treatment of aortic arch aneurysm in the last 10 years. Between March 1985 and December 1993, 83 patients underwent surgery for aortic arch aneurysm. Fifty-one cases had aortic dissection (AD) in the transverse arch and/or its branches, and 32 cases showed true aneurysm (TA) of the aortic arch. In those 83 patients, 37 cases received antegrade CP and 46 cases underwent retrograde CP. Surgical results were compared among the groups by Kaplan-Meier actuarial method and Cox-Mantel statistical analysis. The early mortality after surgery for aortic arch aneurysm was 11.8% in the AD group and 21.9% in the TA group. The early mortality was 21.6% with antegrade CP and 10.9% with retrograde CP. The 6-year actuarial survival rate was 71.7% in the TA group and 67.1% in the AD group. In the AD group, the 3-year survival rate was 93.9% with retrograde CP and 61.1% with antegrade CP (P < 0.005). In the TA group, the 3-year survival rate was similar for antegrade CP (73.3%) and retrograde CP (69.2%). These results suggest that current surgical results of aortic arch aneurysm with hypothermic CP are acceptable and the retrograde CP technique might be recommended, especially for surgery of aortic arch aneurysm with AD.     

A retrospective comparative study of deep hypothermic circulatory arrest, retrograde, and antegrade cerebral perfusion in aortic arch surgery.

OBJECTIVE: Despite theoretical advantages of antegrade (ACP) and retrograde cerebral perfusion (RCP) in addition to deep hypothermic arrest (DHA) in aortic arch surgery, there is still controversy about the best method of cerebral protection. We reviewed our experience with neurological outcome after aortic arch repair over the last five years. METHODS: Sixty-two patients undergoing aortic arch repair were reviewed. Five patients (8.1%) had Marfan's syndrome, 11 (17.7%) had previous cardiac operations, and 13 (21.0%) also received coronary bypass grafting (CABG). The extent of arch replacement was proximal level in 40 (64.5%), distal level in 18 (29.0%), and total in 13 (21.0%). The method of cerebral protection was DHA alone in 14 patients, DHA with RCP in 23, and DHA with ACP in 25. Pre-, intra-, and postoperative variables in the three categories of cerebral protection were compared. Specifically, the independent predictors of mortality, stroke, and temporary neurological dysfunction (TND) were examined. RESULTS: Overall hospital mortality was 5 (8.0%). Stroke occurred in 4 patients (6.4%), and TND in 5 (8.0%). There were no significant differences among the groups in mortality or neurological dysfunction. Total brain exclusion time (TBET) was significantly longer in ACP (DHA, 25.2+/-12.0 min; ACP, 61.8+/-44.1 min; RCP, 36.4+/-20.5 min; p=0.023). Multivariate analysis showed a trend for TBET of longer than 90 minutes as a predictor of stroke (p=0.06; odds ratio, 7.9). The actuarial survival rate was 88.7% at five years (DHA, 85.7%; ACP, 80.0%; RCP, 100%; no significant difference). CONCLUSIONS: Despite more complicated arch repairs requiring a significantly longer cerebral exclusion time which were performed in the group receiving ACP, there was no significant increase in stroke or death rates. Increasing confidence in the ability of ACP has led us to perform the most appropriate arch repair without compromising the extent of replacement for fear of exceeding the "safe" period of circulatory arrest.     

Neurologic outcome after surgery of the aortic arch: Comparison of deep hypothermic arrest,antegrade and retrograde cerebral perfusion

Introduction Neurologic deficits are still a major complication of aortic arch surgery. We therefore compared cerebral protection by deep hypothermic circulatory arrest (DHCA), antegrade (ACP) and retrograde (RCP) cerebral perfusion. Patients and Method 64 consecutive patients who underwent replacement of the aortic arch for aneurysms or dissections from January 1999 through August 2001 were analysed retrospectively for clinical and neurologic outcome. For DHCA core temperature was lowered to 18°C and was kept between 18 and 24°C in the perfused groups. Selective antegrade cerebral perfusion (ACP) was achieved either via the subclavian artery or the brachiocephalic trunc. Retrograde cerebral perfusion (RCP) was performed via the superior vena cava. Results Indication for surgery was type A acute dissection or ruptured aneurysm in 39 patients, chronic dissection and aneurysm without rupture in 25 patients. Operative procedure was partial arch replacement in 46 patients and total arch replacement in 18 patients. For cerebral protection retrograde cerebral perfusion (RCP) was used in 22 Patients (23±11 min.), ACP in 30 patients (25±19 min.) and DHCA in 14 patients (23±13 min.). Mortality was 17% (11 of 64 patients: ACP 7, RCP 2 and DHCA 2). Neurologic deficits occured in 5%, without differences for groups. Conclusion For this patient cohort, needing comparatively short times for aortic arch reconstruction, a low neurologic complication rate without significant differences for the method of cerebral perfusion was observed.     

Impact of retrograde cerebral perfusion on aortic arch aneurysm repair

OBJECTIVE: Protection of the brain is a primary concern in aortic arch surgery. Retrograde cerebral perfusion is a relatively new technique used for cerebral protection during profound hypothermic circulatory arrest. This study was designed to compare, retrospectively, the outcome of 109 patients undergoing aortic arch operation with and without the use of retrograde cerebral perfusion. METHODS: Fifty-five patients had profound hypothermic circulatory arrest alone, and 54 patients had supplemental cerebral protection with retrograde cerebral perfusion. Mean age was 61 +/- 13 years and 58 +/- 14 years, respectively (mean +/- standard deviation). Twenty-two preoperative and intraoperative characteristics, including age, sex, acuity, presence of aortic dissection, and aneurysm rupture, were similar in the 2 groups (P >.05). RESULTS: Mean circulatory arrest times (in minutes) were 30 +/- 19 in the group without retrograde cerebral perfusion and 33 +/- 19 in the group with retrograde cerebral perfusion, respectively. chi(2) Analysis revealed that patients operated on with the use of retrograde cerebral perfusion had significantly lower hospital mortality (15% vs 31%; P =.04) and in-hospital permanent neurologic complications (9% vs 27%; P =.01). Retrograde cerebral perfusion failed to reduce the prevalence of temporary neurologic dysfunction (17% vs 18%; P =.9). Stepwise multiple logistic regression revealed that extracorporeal circulation time, age, and lack of retrograde cerebral perfusion were statistically significant independent risk factors for hospital mortality. The same analysis revealed that lack of retrograde cerebral perfusion was the only significant independent risk factor for permanent neurologic dysfunction. CONCLUSION: Retrograde cerebral perfusion decreased the prevalence of permanent neurologic complications and the hospital mortality in patients undergoing aortic arch operations.     

Total aortic arch replacement under intermittent pressure-augmented retrograde cerebral perfusion

Kitahori, Kawata, Takamoto et al. described the effectiveness of a novel protocol for retrograde cerebral perfusion that included intermittent pressure augmentation for brain protection in a canine model. Based on their report, we applied this novel technique clinically. Although the duration of circulatory arrest with retrograde cerebral perfusion was long, the patient recovered consciousness soon after the operation and had no neurological deficit. Near-infrared oximetry showed recovery of intracranial blood oxygen saturation every time the pressure was augmented.     

pH-stat blood gas management provides better cerebral perfusion during deep hypothermic retrograde cerebral perfusion

We performed a retrospective comparative clinical study to evaluate whether pH-stat (n=14) or alpha-stat strategy (n=15) provides better perfusion or oxygen metabolism during hypothermic retrograde cerebral perfusion (RCP). The pH-stat group showed significantly lower superior vena cava (SVC) pressure (21+/-4 versus 27+/-6 mmHg, P<0.0001), apparently lower retrograde cerebral vascular resistance index (7.4+/-2.1 versus 10.1+/-3.8 dynes/s cm(-5) m(-2), P=0.009) but there were no significant differences in RCP flow index, oxygen supply or oxygen extraction between groups. Further studies are necessary to determine which blood gas management is better for RCP, however, pH-stat strategy should be useful in deep hypothermic RCP.     

Neuropsychometric outcome following aortic arch surgery: a prospective randomized trial of retrograde cerebral perfusion

BACKGROUND: Aortic surgery requiring hypothermic circulatory arrest is associated with a high incidence of brain injury. However, knowledge of neuropsychometric outcome is limited. Retrograde cerebral perfusion has become a popular adjunctive technique to hypothermic circulatory arrest. The aim of this study was to assess neuropsychometric outcome and compare the 2 techniques. METHODS: In a prospective randomized trial, 38 patients requiring elective aortic arch surgery were allocated to either hypothermic circulatory arrest plus retrograde cerebral perfusion or hypothermic circulatory arrest alone. Neuropsychometric testing was performed preoperatively, and at 6 weeks and 12 to 24 weeks postoperatively. Deficit was defined as a 20% decline in 2 tests or more. Standardized Z scores were calculated for each patient and test. Eighteen patients underwent hypothermic circulatory arrest and 20 patients underwent hypothermic circulatory arrest plus retrograde cerebral perfusion. The mean cardiopulmonary bypass, hypothermic circulatory arrest, and retrograde cerebral perfusion durations were 169, 30, and 25 minutes, respectively. RESULTS: There were 2 deaths and 2 neurological deficits. At 6 weeks postoperatively, 77% of the hypothermic circulatory arrest group and 93% of the hypothermic circulatory arrest plus retrograde cerebral perfusion group had a deficit (P =.22). At 12 weeks this was reduced to 55% and 56%, respectively (P =.93). There was a worse total Z test score in the hypothermic circulatory arrest plus retrograde cerebral perfusion group at 12 weeks (P =.05). Neuropsychometric change did not correlate with hypothermic circulatory arrest duration, presence of aortic atheroma, cannulation technique, or procedure. CONCLUSIONS: Hypothermic circulatory arrest plus/minus retrograde cerebral perfusion is associated with a high incidence of neuropsychometric change despite ostensibly normal clinical outcomes and apparently safe arrest duration. Retrograde cerebral perfusion did not improve outcome in this small study.     

Cerebral protection using retrograde cerebral perfusion during hypothermic circulatory arrest

Background

Retrograde cerebral perfusion through the superior vena cava (SVC) has been proposed to protect the brain from ischaemic injury during profound hypothemnic circulatory arrest (PHCA). Its contribution to cerebral protection is unclear. Furthermore, the addition of anaesthetic or vasodilating agents to the SVC perfusate to enhance brain protection, has never been described.

Methods

In three patients undergoing repair of the ascending aorta utilizing PHCA, the upper body was retrogradely perfused with cold (16°C) blood through the SVC by the cardiopulmonary bypass pump. Electroencephalographic activity was monitored using a computenzed electroencephalographic monitor (Cerebro Trac 2500, SRD). Perfusion pressure was measured at a port in the cannula connector. Etomidate or thiopentone was injected into the SVC perfusate to arrest reappearing electroencephalographic activity. Nitroglycerin or nitroprusside was injected into the perfusate to increase retrograde flow and maintain a constant perfusion pressure.

Results

During PHCA penods of up to 61 min, recurrent electroencephalographic activity was abolished by the retrograde administration of small boluses of etomidate (total 50 mg) or thiopentone (total 500 mg). Nitroprusside (100 μg) and nitroglycerin (2 μg · kg^?1 · min^?1) increased retrograde flow from 220 to 550 and 660 ml · min^?1, respectively, while maintaining perfusion pressure (25–26 mmHg). Recovery from anaesthesia and surgery was uneventful, with no adverse neurological sequelae.

Conclusion

Injection of anaesthetic agents into the retrograde SVC perfusate during PHCA, can suppress reoccumng electroencephalographic activity and retrograde injection of vasodilators can facilitate an increase in perfusion. It is suggested that both may augment brain protection.     

Reoperation for interrupted aortic arch with the use of retrograde cerebral perfusion.

We treated 2 patients with recurrent coarctation after repair of interrupted aortic arch. Because they had been operated on with the use of vascular prostheses, severe scarring was considered prohibitive for safe dissection. We successfully carried out anatomic repair with the use of retrograde cerebral perfusion through a left thoracotomy in both cases.     

Optimal perfusion criteria for deep hypothermic selective cerebral perfusion in patients with aortic aneurysm involving aortic arch

Although selective cerebral perfusion (SCP) might be an useful supportive method for aortic arch surgery, its optimal perfusion criteria has not been established. We studied the relationship between the oxygen saturation of superior vena cava or internal jugular vein (SvO2) and the perfusion hemodynamics during deep hypothermic (DH) SCP in twenty patients (pts) (type A dissection; 10, arch aneurysm; 10). SCP was accomplished by perfusion to the brachiocephalic trunk (BCT) and the left common carotid artery (LCC) using separate pumps. Cardiopulmonary bypass and DHSCP time were 128-312 (222 +/- 43, mean +/- SD) minutes and 25-214 (122 +/- 49) minutes, respectively. The cerebral perfusion pressures (CPP) monitored at the bilateral temporal arteries were 20-60 (47 +/- 9) mmHg and cerebral perfusion flow (CPF) was 0.28-0.7 (0.43 +/- 0.10) L/min/m2. The cerebral perfusion score (CPS) defined as CPP X CPF was 7-39 (20 +/- 8). SvO2 ranged from 79 to 99 (94 +/- 7)%. Two operative deaths were encountered from unrelated causes to SCP in both cases. Cerebral infarction occurred in one patient possibly form prolonged low perfusion with low SvO2. When the safety range of SvO2 in DHSCP was defined as greater than 90%, essential criteria to keep this range was CPP greater than 40 mmHg. In 13 out of 15 pts with SvO2 greater than 90%, CPS were above 15. In conclusion, optimal perfusion criteria for DHSCP was defined as CPP greater than 40 mmHg and CPS(CPP X CPF) greater than 15 considering adequate cerebral oxygen consumption.     

Antegrade selective cerebral perfusion with mild hypothermic systemic circulatory arrest during thoracic aortic surgery

Objective Antegrade selective cerebral perfusion (ASCP) and retrograde cerebral perfusion (RCP) have proven to be reliable methods of brain protection during aortic surgery. These techniques are usually accompanied by systemic circulatory arrest with moderate hypothermia (24–28°C) or deep hypothermia (18–24°C). However, hypothermia can lead to various problems. The present study therefore reports results for thoracic aorta replacement using ASCP with mild hypothermic systemic arrest (28–32°C).

Design Between 1995 and 2003, 68 consecutive patients underwent repair of the ascending aorta and/or aortic arch. Mild hypothermic ASCP was utilized in 31 cases, moderate hypothermic ASCP in 20, and deep hypothermic RCP in 17. Various parameters were compared between the mild hypothermic ASCP, moderate hypothermic ASCP, and RCP.

Results Hospital mortality was 10.3%, with no significant differences observed between any groups. Permanent neurological dysfunction was 8.8%, and no significant differences were observed between any groups. Mild hypothermic ASCP displayed significantly decreased transfusion volume, intubation time, and ICU stay.

Conclusions Use of ASCP with mild hypothermic systemic circulatory arrest during aortic surgery resulted in acceptable hospital mortality and neurological outcomes. ASCP with mild hypothermic arrest allows decreased transfusion volume and reduced duration of intubation and ICU stay.