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Objective: We aimed to determine the effects of selective antegrade cerebral perfusion compared with other perfusion strategies on indices of cerebral blood flow, oxygenation, cellular stress, and mitochondrial function., Methods: One-week-old piglets (n = 41) were assigned to 5 treatment groups. Thirty-eight were placed on cardiopulmonary bypass. Of these, 30 were cooled to 18°C and underwent deep hypothermic circulatory arrest (n = 10), underwent selective antegrade cerebral perfusion at 10 mL/kg/min (n = 10), or remained on continuous cardiopulmonary bypass (deep hypothermic cardiopulmonary bypass, n = 10) for 40 minutes. Other subjects remained on normothermic cardiopulmonary bypass (n = 8) or underwent sham surgery (n = 3). Novel, noninvasive optical measurements recorded cerebral blood flow, cerebral tissue oxyhemoglobin concentration, oxygen extraction fraction, total hemoglobin concentration, and cerebral metabolic rate of oxygen. Invasive measurements of cerebral microdialysis and cerebral blood flow were recorded. Cerebral mitochondrial respiration and reactive oxygen species generation were assessed after the piglets were killed., Results: During hypothermia, deep hypothermic circulatory arrest piglets experienced increases in oxygen extraction fraction (P < .001), indicating inadequate matching of oxygen supply and demand. Deep hypothermic cardiopulmonary bypass had higher cerebral blood flow (P = .046), oxyhemoglobin concentration (P = .019), and total hemoglobin concentration (P = .070) than selective antegrade cerebral perfusion, indicating greater oxygen delivery. Deep hypothermic circulatory arrest demonstrated worse mitochondrial function (P < .05), increased reactive oxygen species generation (P < .01), and increased markers of cellular stress (P < .01). Reactive oxygen species generation was increased in deep hypothermic cardiopulmonary bypass compared with selective antegrade cerebral perfusion (P < .05), but without significant microdialysis evidence of cerebral cellular stress., Conclusions: Selective antegrade cerebral perfusion meets cerebral metabolic demand and mitigates cerebral mitochondrial reactive oxygen species generation. Excess oxygen delivery during deep hypothermia may have deleterious effects on cerebral mitochondria that may contribute to adverse neurologic outcomes. We describe noninvasive measurements that may help guide perfusion strategies., (Copyright © 2020 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: We designed a prospective randomized clinical study to compare unilateral and bilateral antegrade cerebral perfusion (ACP) under moderate hypethermia in open distal aortic hemiarch replacement in ascending aortic aneurysm., Methods: Forty-two patients were prospectively randomized into two groups; unilateral ACP to Group 1 and bilateral ACP to Group 2. Inclusion criteria were pathological aortic aneurysm in the ascending aorta and/or aortic arch, elective operation, normal preoperative carotid Doppler ultrasonography, and nonexistence of preoperative neurological event. Patients were evaluated with preoperative and postoperative biochemical blood analysis, magnetic resonance imaging (MRI), and neurological disorders. The primary endpoints were permanent neurological disorder and death., Results: There were 21 patients in each group. Mean age was 56.57 ± 10.06 years in Group 1 and 50.95 ± 15.64 years in Group 2 (p = .170). No significant difference was found according to demographic data. ACP times were significantly higher in bilateral ACP (Group 1: 12.62 ± 5.04 min, Group 2: 18.23 ± 9.04 min, p = .018) whereas cross-clamp time and cardiopulmonary bypass times were not (p = .693 and p = .584 sequentially). Transient neurological disorder was found in seven patients in Group 1 and in 4 patients in Group 2 (p = .484). Postoperative MRI revealed new milimetric ischemic zones in three patients in Group 1 but none in Group 2. No permanent neurological disorder or mortality was seen., Conclusion: The present randomized clinical prospective study could not prove the superiority of one of the technique in cerebral protection probably because, our overall ACP time was too short., (© 2020 Wiley Periodicals LLC.)

Objective: We aimed to monitor regional oxygen saturation levels using near-infrared spectroscopy in patients undergoing total aortic arch replacement and to determine the range of collateral flow via antegrade cerebral perfusion to the spinal cord during lower body circulatory arrest., Methods: Eighteen consecutive patients undergoing total aortic arch replacement in our hospital were prospectively enrolled. Optodes of near-infrared spectroscopy were attached to the skin at the right and left forehead, and above the paravertebral muscles at the level of the third (T3) and tenth (T10) thoracic vertebra. Within- and between-group differences were compared using mixed-effect model repeated-measures analysis., Results: Regional oxygen saturation levels, which had been rapidly declining immediately after circulatory arrest at a tympanic temperature of <25°C and a core temperature of <30°C, showed a rapid increase at the forehead with the initiation of antegrade cerebral perfusion (total flow rate 0.81 ± 0.08 L/min, perfusion pressure 37 ± 6 mm Hg, temperature 25°C). Saturation levels remained only partially elevated at the upper thoracic level (T3) and continued to decline without showing signs of recovery at the lower thoracic level (T10)., Conclusions: Antegrade cerebral perfusion partially perfused the upper thoracic cord via collateral circulation from vertebral arteries through an anterior spinal artery, but it did not reach the lower thoracic cord sufficiently to change the oxygenation level. Cooling is a more important means of protection for the lower spinal cord during lower body circulatory arrest than is antegrade cerebral perfusion., (Copyright © 2019 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: The study objective was to investigate outcomes associated with the application of bilateral or unilateral antegrade cerebral perfusion during surgery for acute type A dissection., Methods: Patients who underwent surgery for type A dissection with the application of antegrade cerebral perfusion between 2009 and 2017 at the Division of Cardiac Surgery, Medical University of Vienna were analyzed retrospectively (bilateral antegrade cerebral perfusion: n = 91, 49.5%; unilateral antegrade cerebral perfusion: n = 93, 50.5%). The primary outcome variable was overall survival. Subgroup analyses were performed in patients requiring antegrade cerebral perfusion durations of 50 minutes or more and less than 50 minutes. Secondary outcome variables were 30-day mortality, adverse outcome, permanent and temporary neurologic deficits, renal replacement therapy, prolonged ventilation, intensive care unit stay, and hospital stay., Results: Multivariable Cox proportional hazards analysis demonstrated no significant association of bilateral antegrade cerebral perfusion with overall survival (hazard ratio, 0.63; 95% confidence interval, 0.34-1.14, P = .126). Propensity score modeling using the method of inverse probability of treatment weighting confirmed this result (hazard ratio, 0.73; 95% confidence interval, 0.33-1.60, P = .428). Bilateral antegrade cerebral perfusion was associated with significantly improved overall survival in patients requiring antegrade cerebral perfusion durations of 50 minutes or more (P = .017). The bilateral antegrade cerebral perfusion and unilateral antegrade cerebral perfusion groups showed comparable rates of secondary outcome variables., Conclusions: In the present study, bilateral antegrade cerebral perfusion and unilateral antegrade cerebral perfusion are associated with comparable outcomes after surgery for type A dissection. Subgroup analyses suggest that bilateral antegrade cerebral perfusion is associated with superior overall survival in patients requiring antegrade cerebral perfusion durations of 50 minutes or more. An adequately powered prospective randomized controlled trial is required to validate these results., (Copyright © 2019 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

This study examines postoperative morbidity and mortality and long-term survival after total arch replacement (TAR) using deep to moderate hypothermic circulatory arrest (HCA), antegrade cerebral perfusion (ACP), and the Y-graft. Seventy-five patients underwent TAR with the Y graft. Deep to moderate HCA was initiated at 18-22°C. ACP was either initiated immediately (early ACP) or after the distal anastomosis was performed (late ACP). The arch vessels were then serially anastomosed to the individual limbs of the Y-graft. The median age was 66 years (range = 32-82). Etiology of aneurysmal dilatation included 20 (27%) patients with medial degenerations, 25 (33%) with chronic dissections, 14 (19%) with acute dissections, 9 (12%) with atherosclerosis and 2 (3%) with Marfan syndrome. In-hospital mortality was 5%. Neurologic complications occurred in 8 (11%) patients; 2 (3%) had strokes and 6 (8%) had transient neurologic deficits. Patients undergoing TAR with moderate hypothermia had a significantly higher incidence of new-onset renal insufficiency (3 [23%] vs [0%], P < 0.001) and TND (3 (23%) vs 3 (5%), P = 0.028) than the profound and deep hypothermia cohort. Excluding the 1 patient who died intraoperatively, 89% (95%CI: 79-94%) were alive at 1 year, 78% at 5 years (95%CI: 66-86%), and 73% at 10 years (95%CI: 59-82%). The combination of deep to moderate HCA, ACP, and the Y-graft is a safe and reproducible technique. Further inquiry is needed to assess if early ACP provides superior clinical outcomes., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Antegrade cerebral perfusion (ACP) is the standard neuroprotection method in aortic surgery. Visceral ischemia during this modality brings out some controversies. We aimed to investigate the level of oxidative stress at the lower part of body during ACP. Methods: Thirty consecutive patients underwent elective ascending aorta and hemiarch repair with ACP (without distal perfusion) were enrolled to study. The patients were enrolled into two groups which were based on 50th percentile of ACP duration (15 patients in each group). Blood samples from inferior vena cava at the end of ACP were collected to assess oxidative stress with biochemical parameters such as lactate, advanced oxidative protein products (AOPP) and thiol levels. Clinical follow-up parameters regarding to visceral and spinal cord ischemia were recorded. There were no clinical complications at both groups. Results: Mean ACP duration for the study group was found to be 15 min (10-28 min). Lactate, AOPP, and thiol levels were found to be similar between two groups. Furthermore, correlation analysis revealed only low level of correlation between ACP duration and lactate levels. Renal and liver function tests were found to be similar between groups. Conclusions: Immediate parameters (such as lactate, AOPP, and thiol) that show alterations in response to oxidative stress were not affected by the duration of ACP. Therefore, ACP without distal perfusion may not be harmful when conducted for short duration.

Background: Antegrade cerebral perfusion (ACP) is the most widely used cerebral protection strategy for complex aortic repair and includes unilateral (u-ACP) and bilateral (b-ACP) techniques. The superiority of b-ACP over u-ACP has been the subject of much debate. Focusing on type A aortic dissection requiring total arch replacement, we investigated the clinical effects of b-ACP versus u-ACP., Methods: Between September 2006 and August 2014, 203 patients presenting with type A aortic dissection (median age, 51.0 ± 13 years; range, 17-72 years; 128 males) underwent total aortic arch replacement with hypothermic circulatory arrest. ACP was used in all patients, including u-ACP in 82 (40.3%) and b-ACP in 121 (59.7%)., Results: There was no significant difference between the u-ACP and b-ACP groups in terms of cardiopulmonary bypass (CPB) time, cross-clamp time, or circulatory arrest time. Overall 30-day mortality was comparable in the 2 groups (11.6% for b-ACP vs 20.7% for u-ACP; P = .075). The prevalence of postoperative permanent neurologic dysfunction (PND) was comparable as well (8.4% vs 16.9%; P = .091). Mean ventilation time was lower in the b-ACP group (95.5 ± 45.25 hours vs 147.0 ± 82 hours; P < .001). Mean lengths of stay in the intensive care unit and the hospital overall were comparable in the 2 groups (intensive care unit: 16 ± 17.75 days vs 17 ± 11.5 days, P = .454; hospital: 26.5 ± 20.6 days vs 24.8 ± 10.3 days, P = .434). The P values from logistic regression models indicated that in the 2 groups combined, CPB time and circulatory arrest time were independent risk factors for both mortality and PND., Conclusions: In this, the first published study focusing on the efficacy of u-ACP and b-ACP in total arch replacement for type A aortic dissection, the b-ACP group did not demonstrate significantly lower 30-day mortality or PND rate compared with the u-ACP group. Future large-sample studies are warranted to thoroughly examine this critical issue., (Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Neurologic injury is a potentially devastating complication of aortic surgery. The methods used in aortic surgery, including systemic cooling, initiation of circulatory arrest, and rewarming during the replacement of the aortic arch, are the most complex circulatory management and surgical procedures performed in modern-day surgery. Despite the plethora of published literature, neuroprotection in aortic surgery is largely based on observational studies and institutional-based practices. This article summarizes the current evidence and emerging strategies for neuroprotection in aortic arch operations., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Introduction: Neurological injury remains the major cause of morbidity and mortality following open aortic arch repair. Systemic hypothermia along with antegrade cerebral perfusion (ACP) is the accepted cerebral protection approach, with axillary artery cannulation being the most common technique used to establish ACP. More recently, innominate artery cannulation has been shown to be a safe and efficacious method for establishing ACP. Inasmuch as there is a lack of high-quality data comparing axillary and innominate artery ACP, we have designed a randomised, multi-centre clinical trial to compare both cerebral perfusion strategies with regards to brain morphological injury using diffusion-weighted MRI (DW-MRI)., Methods and Analysis: 110 patients undergoing elective aortic surgery with repair of the proximal arch requiring an open distal anastamosis will be randomised to either the innominate artery or the axillary artery cannulation strategy for establishing unilateral ACP during systemic circulatory arrest with moderate levels of hypothermia. The primary safety endpoint of this trial is the proportion of patients with new radiologically significant ischaemic lesions found on postoperative DW-MRI compared with preoperative DW-MRI. The primary efficacy endpoint of this trial is the difference in total operative time between the innominate artery and the axillary artery cannulation group., Ethics and Dissemination: The study protocol and consent forms have been approved by the participating local research ethics boards. Publication of the study results is anticipated in 2018 or 2019. If this study shows that the innominate artery cannulation technique is non-inferior to the axillary artery cannulation technique with regards to brain morphological injury, it will establish the innominate artery cannulation technique as a safe and potentially more efficient method of antegrade cerebral perfusion in aortic surgery., Trial Registration Number: NCT02554032., Competing Interests: Competing interests: MDP has received research grant support and speaker/consulting honoraria from Edwards Lifesciences. MWAC has received speaker/consulting honoraria from Medtronic, Canada, Edwards Lifesciences, Livanova and Symetis. The other authors have no conflicts to declare., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: Antegrade cerebral perfusion in aortic surgery is a well-established brain protection method. Open distal anastomosis during aortic surgery has some well-known advantages. Antegrade cerebral perfusion allows repair to some extent of the aortic arch, even in isolated ascending aortic aneurysm. The present study aims to investigate the adequacy of contralateral perfusion with novel oxidative stress parameters during unilateral antegrade cerebral perfusion., Method: The study included 30 consecutive patients undergoing thoracic aortic surgery with unilateral antegrade cerebral perfusion (uACP) under moderate hypothermia (28° C). Blood samples from right and left jugular vein were obtained at four time intervals during surgery (after the anaesthetic induction - Phase 1, at the beginning of cardiopulmonary bypass - Phase 2, 15 th minute of uACP - Phase 3 and after weaning from cardiopulmonary bypass - Phase 4). Novel oxidative stress parameters (advanced oxidation protein products, sialic acid, thiol reagents and ischaemia-modified serum albumin), blood gas analysis, and serum glucose and lactate levels were measured. In addition, intraoperative and early postoperative follow-up parameters were recorded., Results: Mean unilateral antegrade cerebral perfusion time was observed to be 16.4±5.9min (9 - 46min). No significant differences between right and left hemispheres were observed in novel oxidative parameters or biochemical values. There was only one temporary neurological deficit (3.3%) in the patient group., Conclusions: The present study demonstrated that open distal anastomosis for hemiarch repair can be performed safely with unilateral antegrade cerebral perfusion under moderate hypothermia with both clinical outcome and novel biomarkers., (Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Objective: We examined the early outcomes and the long-term survival associated with different degrees of hypothermia in patients who received antegrade cerebral perfusion (ACP) for >30 minutes., Methods: During a 10-year period, 544 consecutive patients underwent proximal and total aortic arch surgery and received ACP for >30 minutes and 1 of 3 levels of hypothermia: deep (14.1°C-20°C; n = 116 [21.3%]), low-moderate (20.1°C-23.9°C; n = 262 [48.2%]), and high-moderate (24°C-28°C; n = 166 [30.5%]). A variable called "predicted temperature" was used in propensity-score analysis. Multivariate analysis was done to evaluate the effect of actual temperature on outcomes., Results: The operative mortality rate was 12.5% (n = 68) overall and was 15.5%, 11.8%, and 11.5% in the deep, low-moderate, and high-moderate hypothermia patients, respectively (P = .54). The persistent stroke rate was 6.6% overall and 12.2%, 4.6%, and 6.0% in these 3 groups, respectively (P = .024 on univariate analysis). On multivariate analysis, actual temperature was not associated with mortality, but lower temperatures predicted persistent stroke and reoperation for bleeding. In the propensity-matched subgroups, the patients with predicted deep hypothermia had (nonsignificantly) greater rates of persistent stroke (12.2% vs 4.9%; relative risk, 1.08; 95% CI, 0.87-1.15) and reoperation for bleeding (14.6% vs 2.4%; relative risk, 1.14; 95% CI, 0.87-1.15) than the patients with predicted moderate hypothermia. On long-term follow-up (mean duration, 5.12 years), 4- and 8-year survival rates were 62.3% and 55.7% in the deep hypothermia group and 75.4% and 74.2% in the moderate hypothermia group (P = .0015)., Conclusions: In proximal and arch operations involving ACP for >30 minutes, greater actual temperatures were associated with less stroke and reoperation for bleeding. There were no significant differences among the predicted hypothermia levels, although a trend toward a higher rate of adverse events was noticed in the deep hypothermia group. Long-term survival was better in the moderate hypothermia group., (Copyright © 2016 The American Association for Thoracic Surgery. All rights reserved.)

Objective: Our objective was to determine whether the use of unilateral (u-ACP) or bilateral antegrade cerebral perfusion (b-ACP) results in different mortality and neurologic outcomes after complex aortic surgery., Methods: PubMed, Embase, and the Cochrane Library were searched for studies reporting on postoperative mortality and permanent (PND) and temporary neurologic dysfunction (TND) in complex aortic surgery requiring circulatory arrest with antegrade cerebral protection. Analysis of heterogeneity was performed with the Cochrane Q statistic., Results: Twenty-eight studies were analyzed for a total of 1894 patients receiving u-ACP versus 3206 receiving b-ACP. Pooled analysis showed similar rates of 30-day mortality (8.6% vs 9.2% for u-ACP and b-ACP, respectively; P = .78), PND (6.1% vs 6.5%; P = .80), and TND (7.1% vs 8.8%; P = .46). Age, sex, and cardiopulmonary bypass time did not influence effect size estimates. Higher rates of postoperative mortality and PND were among nonelective operations and for highest temperatures and duration of the circulatory arrest. The Egger test excluded publication bias for the outcomes investigated., Conclusions: This meta-analysis shows that b-ACP and u-ACP have similar postoperative mortality and both PND and TND rates after circulatory arrest for complex aortic surgery., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: We retrospectively performed a comparative analysis of temperature measurement sites during surgical repair of the thoracic aorta., Methods: Between January 2004 and May 2006, 22 patients (mean age: 63 ± 12 years) underwent operations on the thoracic aorta with arterial cannulation of the aortic arch concavity and selective antegrade cerebral perfusion (ACP) during deep hypothermic circulatory arrest (HCA). Indications for surgical intervention were acute type A dissection in 14 (64%) patients, degenerative aneurysm in 6 (27%), aortic infiltration of thymic carcinoma in 1 (4.5%) and intra-aortic stent refixation in 1 (4.5%). Rectal, tympanic and bladder temperatures were evaluated to identify the best reference to arterial blood temperature during HCA and ACP., Results: There were no operative deaths and the 30-day mortality rate was 13% (three patients). Permanent neurological deficits were not observed and transient changes occurred in two patients (9%). During re-warming, there was strong correlation between tympanic and arterial blood temperatures (r = 0.9541, p<0.001), in contrast to the rectal and bladder temperature (r = 0.7654, p = n.s; r = 0.7939, p = n.s., respectively)., Conclusion: We conclude that tympanic temperature measurements correlate with arterial blood temperature monitoring during aortic surgery with HCA and ACP and, therefore, should replace bladder and rectal measurements.