Retrograde cerebral perfusion reduces embolic and watershed lesions after acute type a aortic dissection repair with deep hypothermic circulatory arrest.

BACKGROUND: To assess whether retrograde cerebral perfusion reduces neurological injury and mortality in patients undergoing surgery for acute type A aortic dissection. METHODS: Single-center, retrospective, observational study including all patients undergoing acute type A aortic dissection repair with deep hypothermic circulatory arrest between January 1998 and December 2022 with or without the adjunct of retrograde cerebral perfusion. 515 patients were included: 257 patients with hypothermic circulatory arrest only and 258 patients with hypothermic circulatory arrest and retrograde cerebral perfusion. The primary endpoints were clinical neurological injury, embolic lesions, and watershed lesions. Multivariable logistic regression was performed to identify independent predictors of the primary outcomes. Survival analysis was performed using Kaplan-Meier estimates. RESULTS: Clinical neurological injury and embolic lesions were less frequent in patients with retrograde cerebral perfusion (20.2% vs. 28.4%, p = 0.041 and 13.7% vs. 23.4%, p = 0.010, respectively), but there was no significant difference in the occurrence of watershed lesions (3.0% vs. 6.1%, p = 0.156). However, after multivariable logistic regression, retrograde cerebral perfusion was associated with a significant reduction of clinical neurological injury (OR: 0.60; 95% CI 0.36-0.995, p = 0.049), embolic lesions (OR: 0.55; 95% CI 0.31-0.97, p = 0.041), and watershed lesions (OR: 0.25; 95%CI 0.07-0.80, p = 0.027). There was no significant difference in 30-day mortality (12.8% vs. 11.7%, p = ns) or long-term survival between groups. CONCLUSION: In this study, we showed that the addition of retrograde cerebral perfusion during hypothermic circulatory arrest in the setting of acute type A aortic dissection repair reduced the risk of clinical neurological injury, embolic lesions, and watershed lesions.

Clinical outcome of a branch-first approach with a novel continuous whole-brain perfusion strategy for total arch surgery.

BACKGROUND: Cerebral protection strategies have been investigated since the introduction of aortic arch surgery and have been modified over the centuries. However, the cerebral protective effects of unilateral and bilateral antegrade cerebral perfusion are similar, with opportunities for further improvement. METHODS: A total of 30 patients who underwent total arch surgery were enrolled in this study. Patients were assigned to the novel continuous whole-brain or unilateral antegrade cerebral perfusion group according to the cerebral perfusion technique used. Preoperative clinical data and 1-year postoperative follow-up data were collected and analyzed. RESULTS: There were no significant differences between the two groups in terms of the incidence of permanent neurological deficit, mortality, or therapeutic efficacy. However, the incidence of temporary neurological dysfunction in the novel whole-brain perfusion group was significantly lower than that in the unilateral antegrade cerebral perfusion group. CONCLUSIONS: In this study, the branch-first approach with a novel whole-brain perfusion strategy had no obvious disadvantages compared with unilateral antegrade cerebral perfusion in terms of cerebral protection and surgical safety. These findings suggest that this new technique is feasible and has application value for total arch surgery.

Cannula Placement for Cerebral Protection Without Circulatory Arrest in Patients Undergoing Hemiarch Aortic Aneurysm Repair.

BACKGROUND: Aortic aneurysms involving the proximal aortic arch, which require hemiarch-type repair, typically require circulatory arrest with antegrade cerebral perfusion. Left carotid antegrade cerebral perfusion (LCP) via distal arch cannulation without circulatory arrest was used in this study's patient population. The goal was to assess the operative efficiency and clinical outcomes of using a distal arch cannulation technique that would not require any hypothermic circulatory arrest (HCA) time compared with more traditional brachiocephalic artery cannulation with right-sided unilateral antegrade cerebral perfusion (RCP) and HCA. METHODS: A single-center retrospective review of patients with replacement of the distal ascending aorta involving the proximal arch was performed. Patients with an intramural hematoma or dissection were excluded. Between January 2015 and December 2019, 68 adult patients had undergone a hemiarch repair because of aneurysmal disease. Analysis of baseline demographics, operative data, and clinical outcomes was performed. RESULTS: Comparing the 68 patients: 21 patients were treated with RCP (via brachiocephalic artery graft with HCA), and 47 patients were treated with LCP (via distal aortic arch cannulation with cross-clamp between the brachiocephalic and left common carotid arteries without HCA). Baseline characteristics and outcomes were evaluated for both groups. The LCP group was younger (LCP median [IQR] age, 60 [53-65] years vs RCP median [IQR] age, 67 [59-71] years]. Sex, race, body mass index, comorbidities, and ejection fraction were similar between the groups. Cardiopulmonary bypass time (LCP, 123 minutes vs RCP, 149 minutes) and unilateral cerebral perfusion time (LCP, 17 minutes vs RCP, 22 minutes) were longer in the RCP group. Bleeding, prolonged ventilatory support, kidney failure, and length of stay were similar. In-hospital mortality was 2% in the LCP group vs 0% in the RCP group. Stroke occurred in 2 patients (4.2%) in the LCP group and in 0% of the RCP group. Mortality at 6 months in the LCP and RCP groups was 3% and 10%, respectively. CONCLUSION: Distal arch cannulation with LCP without HCA is a reasonable and safe alternative strategy for patients requiring hemiarch replacement for aneurysmal disease. This technique may provide additional benefits by avoiding circulatory arrest in these complex cases.

Is Deep Hypothermic Cardiac Arrest Mandatory in Aortic Arch Surgeries?

Cannulation strategies in aortic arch surgeries are a matter of immense discussion. Majority of time deep hypothermic circulatory arrest (DHCA) is the way out, but it does come with its set of demerits. Here we demonstrate a case with aortic arch dissection dealt with dual cannulation strategy in axillary and femoral artery without need for DHCA and ensuring complete neuroprotection of brain and spinal cord without hinderance of time factor. Inception of new ideas like this may decrease the need for DHCA and hence its drawbacks, thus decreasing the morbidity and mortality associated.

Cognitive Effects of Body Temperature During Hypothermic Circulatory Arrest Trial (GOT ICE): A Randomized Clinical Trial Comparing Outcomes After Aortic Arch Surgery.

BACKGROUND: Deep hypothermia has been the standard for hypothermic circulatory arrest (HCA) during aortic arch surgery. However, centers worldwide have shifted toward lesser hypothermia with antegrade cerebral perfusion. This has been supported by retrospective data, but there has yet to be a multicenter, prospective randomized study comparing deep versus moderate hypothermia during HCA. METHODS: This was a randomized single-blind trial (GOT ICE [Cognitive Effects of Body Temperature During Hypothermic Circulatory Arrest]) of patients undergoing arch surgery with HCA plus antegrade cerebral perfusion at 4 US referral aortic centers (August 2016-December 2021). Patients were randomized to 1 of 3 hypothermia groups: DP, deep (≤20.0 °C); LM, low-moderate (20.1-24.0 °C); and HM, high-moderate (24.1-28.0 °C). The primary outcome was composite global cognitive change score between baseline and 4 weeks postoperatively. Analysis followed the intention-to-treat principle to evaluate if: (1) LM noninferior to DP on global cognitive change score; (2) DP superior to HM. The secondary outcomes were domain-specific cognitive change scores, neuroimaging findings, quality of life, and adverse events. RESULTS: A total of 308 patients consented; 282 met inclusion and were randomized. A total of 273 completed surgery, and 251 completed the 4-week follow-up (DP, 85 [34%]; LM, 80 [34%]; HM, 86 [34%]). Mean global cognitive change score from baseline to 4 weeks in the LM group was noninferior to the DP group; likewise, no significant difference was observed between DP and HM. Noninferiority of LM versus DP, and lack of difference between DP and HM, remained for domain-specific cognitive change scores, except structured verbal memory, with noninferiority of LM versus DP not established and structured verbal memory better preserved in DP versus HM (P = 0.036). There were no significant differences in structural or functional magnetic resonance imaging brain imaging between groups postoperatively. Regardless of temperature, patients who underwent HCA demonstrated significant reductions in cerebral gray matter volume, cortical thickness, and regional brain functional connectivity. Thirty-day in-hospital mortality, major morbidity, and quality of life were not different between groups. CONCLUSIONS: This randomized multicenter study evaluating arch surgery HCA temperature strategies found low-moderate hypothermia noninferior to traditional deep hypothermia on global cognitive change 4 weeks after surgery, although in secondary analysis, structured verbal memory was better preserved in the deep group. The verbal memory differences in the low- and high-moderate groups and structural and functional connectivity reductions from baseline merit further investigation and suggest opportunities to further optimize brain perfusion during HCA. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02834065.

Early outcome of simplified total arch reconstruction under mild hypothermia (30-32 °C) with distal aortic perfusion.

OBJECTIVE: We designed a simplified total arch reconstruction (s-TAR) technique which could be performed under mild hypothermia (30-32 °C) with distal aortic perfusion. This study aimed to compare its efficacy of organ protection with the conventional total arch reconstruction (c-TAR). METHODS: We reviewed the clinical data of 195 patients who had ascending aortic aneurysm with extended aortic arch dilation and underwent simultaneous ascending aorta replacement and TAR procedure between January 2018 and December 2022 in our center. 105 received c-TAR under moderate hypothermia (25-28 °C) with circulatory arrest (c-TAR group); rest 90 received s-TAR under mild hypothermia (30-32 °C) with distal aortic perfusion (s-TAR group). RESULTS: The s-TAR group demonstrated shorter CPB time, cross-clamp time and lower body circulatory arrest time compared with the c-TAR group. The 30-day mortality was 2.9% for the c-TAR group and 1.1% for the s-TAR group (P = 0.043). The mean duration of mechanical ventilation was shorter in the s-TAR group. Paraplegia was observed in 4 of 105 patients (3.8%) in the c-TAR group, while no such events were observed in the s-TAR group. The incidence of temporary neurologic dysfunction was significantly higher in the c-TAR group. The incidence of permanent neurologic dysfunction also showed a tendency to be higher in the c-TAR group, without statistical significance. Furthermore, the incidence of reoperation for bleeding were significantly lower in the s-TAR group. The rate of postoperative hepatic dysfunction and all grades of AKI was remarkably lower in the s-TAR group. The 3-year survival rate was 95.6% in the s-TAR group and 91.4% in the c-TAR group. CONCLUSIONS: s-TAR under mild hypothermia (30-32℃) with distal aortic perfusion is associated with lower mortality and morbidity, offering better neurological and visceral organ protection compared with c-TAR.

Risk Factors for Stroke Development After Thoracic Aortic Surgery.

OBJECTIVES: Stroke after thoracic aortic surgery is a complication that is associated with poor outcomes. The aim is to characterize the intraoperative risk factors for stroke development. DESIGN: A retrospective analysis. SETTING: Tertiary, high-volume cardiac surgery center. PARTICIPANTS: Patients who had surgical repair of thoracic aortic diseases from January 1, 2017, through December 31, 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 704 patients were included, of whom 533 had ascending aortic aneurysms, and 171 had type A aortic dissection. The incidence of postoperative stroke was 4.5% (95% CI 2.9%-6.6%) for ascending aortic aneurysms compared with 12.3% (95% CI 7.8%-18.16%) in type-A aortic dissections. Patients who developed postoperative strokes had significantly lower intraoperative hemoglobin median (7.5 gm/dL [IQR 6.8-8.6] v 8.55 gm/dL [IQR 7.3-10.0]; p < 0.001). The median cardiopulmonary bypass time was 185 minutes (IQR 136-328) in the stroke group versus 156 minutes (IQR 113-206) in the nonstroke group (p = 0.014). Circulatory arrest was used in 57.8% versus 38.5% of the nonstroke patients (p = 0.017). The initial temperature after leaving the operating room was lower, with a median of 35.0°C (IQR 34-35.92) in the stroke group versus 35.5°C (IQR 35-36) in the nonstroke cohort (p = 0.021). CONCLUSIONS: This single-center study highlighted the potential importance of intra-operative factors in preventing stroke. Lower hemoglobin, longer duration of cardiopulmonary bypass, deep hypothermic circulatory arrest, and postoperative hypothermia are potential risk factors for postoperative stroke. Further studies are needed to prevent this significant complication in patients with thoracic aortic diseases.

Hypothermic Circulatory Arrest in Adult Aortic Arch Surgery: A Review of Hypothermic Circulatory Arrest and its Anesthetic Implications.

Diseases affecting the aortic arch often require surgical intervention. Hypothermic circulatory arrest (HCA) enables a safe approach during open aortic arch surgeries. Additionally, HCA provides neuroprotection by reducing cerebral metabolism and oxygen requirements. However, HCA comes with significant risks (eg, neurologic dysfunction, stroke, and coagulopathy), and the cardiac anesthesiologist must completely understand the surgical techniques, possible complications, and management strategies.

Incidence and clinical impact of silent pancreatitis after aortic arch surgery.

BACKGROUND: This study was designed to investigate the incidence and types of pancreatic injury, risk factors, and time-course changes in computed tomographic findings following total aortic arch replacement with moderate hypothermic circulatory arrest. METHODS: Medical records of patients who underwent total arch replacement between January 2006 and August 2021 were retrospectively reviewed. A comparison study between the patients with (group P) and without pancreatic injury (group N) was conducted to elucidate the impact of pancreatic injury. Follow-up computed tomography of the patients in group P was reviewed to investigate time-course changes of the pancreatic injury. RESULTS: Of 353 patients, 14 (4.0%) had subclinical pancreatic injury. Computed tomographic findings were consistent with acute pancreatitis in all patients, of whom eight patients had interstitial edematous pancreatitis, whereas six patients had necrotizing pancreatitis. Although walled-off necrosis occurred in three patients, none of them required drainage. In-hospital mortality was 7.1% and 4.4% in groups P and N, respectively (p = 0.98). The 5-year actuarial survival rates were 77.9% and 81.0% in groups P and N, respectively (p = 0.51). Multivariate analysis revealed that pancreatic injury was associated with chronic obstructive pulmonary disease (p = 0.03). CONCLUSIONS: This study highlighted that silent pancreatic injury after aortic arch surgery is underrecognized. Potential arterial sclerosis of the pancreatic circulation seems to be related to pancreatic injury.

Transcriptomic Profiling of circRNAs in rat Hippocampus after Deep Hypothermic Circulatory Arrest.

Neurologic abnormalities occurring after deep hypothermic circulatory arrest (DHCA) remain a significant concern. However, molecular mechanisms leading to DHCA-related cerebral injury are still ill-defined. Circular RNAs (circRNAs) are a class of covalently closed non-coding RNAs and can play important roles in different types of cerebral injury. This study aimed to investigate circRNAs expression profiles in rat hippocampus after DHCA and explore the potential functions of circRNAs in DHCA-related cerebral injury. Hence, the DHCA procedure in rats was established and a transcriptomic profiling of circRNAs in rat hippocampus was done. As a result, a total of 35192 circRNAs were identified. Among them, 339 circRNAs were dysregulated, including 194 down-regulated and 145 up-regulated between DHCA and sham group. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed based on the host genes of all dysregulated circRNAs. Also, 4 circRNAs were validated by RT-qPCR (rno_circ_0028462, rno_circ_0037165, rno_circ_0045161 and rno_circ_0019047). Then a circRNA-microRNA (miRNA) interaction network involving 4 candidate circRNAs was constructed. Furthermore, functional enrichment analysis of the miRNA-targeting mRNAs of every candidate circRNA was conducted to gain insight into each of the 4 circRNAs. Our study provided a better understanding of circRNAs in the mechanisms of DHCA-related cerebral injury and some potential targets for neuroprotection.

Determination of selective antegrade perfusion flow rate in aortic arch surgery to restore baseline cerebral near-infrared spectroscopy values: a single-centre observational study.

OBJECTIVES: Neuroprotection during aortic arch surgery involves selective antegrade cerebral perfusion. The parameters of cerebral perfusion, e.g. flow rate, are inconsistent across centres and are subject of debate. The aim of this study was to determine the cerebral perfusion flow rate during hypothermic circulatory arrest required to meet preoperative awake baseline regional cerebral oxygen saturation (rSO2). METHODS: Patients scheduled for aortic arch surgery with hypothermic circulatory arrest were enrolled in this prospective observational study. After initiation of hypothermic circulatory arrest, bilateral selective antegrade cerebral perfusion was established and cerebral flow rate was continuously increased. The primary end point was the difference of cerebral saturation from baseline during cerebral perfusion flow rates of 6, 8 and 10 ml/kg/min. RESULTS: A total of 40 patients were included. During antegrade cerebral perfusion, rSO2 was significantly lower than the baseline at 6 ml/kg/min [-7.3, 95% confidence interval (CI): -1.7, -12.9; P = 0.0015]. In contrast, flow rates of 8 and 10 ml/kg/min resulted in rSO2 that did not significantly differ from the baseline (-2; 95% CI: -4.3, 8.3; P > 0.99 and 1.8; 95% CI: -8.5%, 4.8%; P > 0.99). Cerebral saturation was significantly more likely to meet baseline values during selective antegrade cerebral perfusion with 8 ml/kg/min than at 6 ml/kg/min (44.1%; 95% CI: 27.4%, 60.8% vs 11.8%; 95% CI: 0.9%, 22.6%; P = 0.0001). CONCLUSIONS: At 8 ml/kg/min cerebral flow rate during selective antegrade cerebral perfusion, regional cerebral oximetry baseline values are significantly more likely to be achieved than at 6 ml/kg/min. Further increasing the cerebral flow rate to 10 ml/kg/min does not significantly improve rSO2.

[Risk factors of hyperlactatemia during pulmonary endarterectomy under deep hypothermic circulatory arrest and its influence on prognosis].

Objective: To investigate the incidence, risk factors, and outcomes of hyperlactatemia after pulmonary endarterectomy (PEA) under deep hypothermic circulatory arrest (DHCA). Methods: From December 2016 to January 2022, patients receiving PEA in China-Japan Friendship Hospital were enrolled in the study. Arterial blood samples were analyzed intraoperatively. Multivariate logistic regression analysis was performed to identify the predictors of intraoperative lactate elevation as well as major factors influencing the clinical outcome of the surgery. Results: A total of 110 patients (69 males and 41 females) were enrolled, aged (50.6±12.8) years. Receiver operating characteristic curve yielded an optimal cut-off lactate level of 7 mmol/L for predicting major postoperative complications (re-operation, re-intubation, postoperative renal failure requiring renal replacement therapy, wound infection, stroke, atrial fibrillation, and perioperative extracorporeal membrane oxygenation usage within 48 hours after surgery). Thirty-nine patients (35.5%) had an intraoperative peak arterial lactate level of≥7 mmol/L. According to intraoperative peak arterial lactate level, the patients were divided into two groups (<7 mmol/L and≥7 mmol/L). There were no statistically significant differences in age, sex and body mass index between the two groups (all P>0.05). Intraoperative peak lactate level was associated with prolonged mechanical ventilation time (r=0.262, P=0.008) and intensive care unit length of stay (r=0.304, P=0.002). Multivariate logistic regression analysis identified three key variables associated with lactate level≥7 mmol/L: DHCA duration (OR=1.186, 95%CI: 1.027-1.370, P=0.020), nadir hematocrit (HCT) (OR=0.580, 95%CI: 0.341-0.988, P=0.045) and preoperative pulmonary vascular resistance (PVR) (OR=1.096, 95%CI: 1.020-1.177, P=0.012). Patients with lactate≥7 mmol/L carried a higher rate of major complications (P=0.001). For patients with lactate≥7 mmol/L, 41.0% (16 out of 39 cases) had major complications, while for patients with lactate<7 mmol/L, only 14.1% (10 out of 71) had major complications. There was no statistically significant difference in mortality (8.5% vs 10.3%, P=0.753) between patients with different lactate levels. Moreover, intraoperative peak lactate level was a predictor of postoperative combined morbidity (OR=1.625, 95%CI: 1.176-2.245, P=0.003). Conclusion: High intraoperative lactate levels are associated with higher preoperative PVR, lower nadir HCT, and longer DHCA duration. Intraoperative lactate levels are independently associated with increased combined morbidity.

The use of blood and blood products in aortic surgery is associated with adverse outcomes.

OBJECTIVE: To report long-term outcomes after deep hypothermic circulatory arrest (DHCA) with or without perioperative blood or blood products. METHODS: All patients who underwent proximal aortic surgery with DHCA from 2011 to 2018 were propensity matched according to baseline characteristics. Primary outcomes included short- and long-term mortality. Stratified Cox regression analysis was performed for significant associations with survival. RESULTS: A total of 824 patients underwent aortic replacement requiring circulatory arrest. After matching, there were 224 patients in each arm (transfusion and no transfusion). All baseline characteristics were well matched, with a standardized mean difference (SMD) <0.1. Preoperative hematocrit (41.0 vs 40.6; SMD = 0.05) and ejection fraction (57.5% vs 57.0%; SMD = 0.08) were similar between the no transfusion and blood product transfusion cohorts. Rate of aortic dissection (42.9% vs 45.1%; SMD = 0.05), hemiarch replacement (70.1% vs 70.1%; SMD = 0.00), and total arch replacement (21.9% vs 23.2%; SMD = 0.03) were not statistically different. Cardiopulmonary bypass and cross-clamp time were higher in the blood product transfusion cohort (P < .001). Operative mortality (9.4% vs 2.7%; P = .003), stroke (7.6% vs 1.3%; P = .001), reoperation rate, pneumonia, prolonged ventilation, and dialysis requirements were significantly higher in the transfusion cohort (P < .001). In stratified Cox regression, transfusion was an independent predictor of mortality (hazard ratio, 2.62 [confidence interval, 1.47-4.67]; P = .001). One- and 5-year survival were significantly reduced for the transfusion cohort (P < .001). CONCLUSIONS: In patients who underwent aortic surgery with DHCA, perioperative transfusions were associated with poor outcomes despite matching for preoperative baseline characteristics.

Application of deep hypothermic circulatory arrest in open left chest aortic aneurysm repair.

OBJECTIVES: Deep hypothermic circulatory arrest (DHCA) is often required for patients undergoing repair of descending thoracic aortic aneurysm (DTAA) or thoracoabdominal aortic aneurysm via left thoracotomy when proximal crossclamping is not feasible or when aneurysmal disease extends into the transverse aortic arch. Historical literature suggests higher complications rates due to the technical complexity of this approach; we examined outcomes with this approach at our center. METHODS: Between January 2008 and May 2018, 84 patients with DTAA or Crawford extent I thoracoabdominal aortic aneurysm underwent open repair. DHCA was employed in 46 of 84 (55%) patients, of which 33 (72%) required repair of distal arch and DTAA, and 13 (28%) required repair of the distal arch and extent I thoracoabdominal aortic aneurysm. Patients who underwent DHCA had more chronic dissections than those in the non-DHCA group (70% vs 34%; P ≤ .05). RESULTS: Major adverse outcomes for the DHCA group versus non-DHCA group were as follows: early mortality 3 out of 46 (7%) versus 4 out of 38 (11%) (P = .70), stroke 3 out of 46 (7%) versus 1 out of 38 (3%) (P = .62), permanent spinal cord deficit 2 out of 46 (4%) versus 3 out of 38 (8%) (P = .65), permanent renal failure necessitating dialysis 1 out of 46 (2%) versus 2 out of 38 (5%) (P = .59). Freedom from major adverse outcomes was 38 out of 46 (83%) versus 31 out of 38 (82%) for DHCA versus non-DHCA (P = 1). CONCLUSIONS: DHCA can be employed via left thoracotomy for combined arch and DTAA or extent I thoracoabdominal aortic aneurysm open repair.

Perfusion of brain and viscera using modified retrograde cerebral perfusion for aortic arch surgery.

Anterograde or retrograde cerebral perfusion can protect the brain from ischemic injury during hypothermic circulatory arrest (HCA), but neither type of perfusion provides blood flow to the abdominal viscera. Here, we report a modified retrograde cerebral perfusion (RCP) technique in which we tethered both superior and inferior venae cavae with bands around the cannula and clamped the distal ends of the drainage tubes of both venae cavae. Modified RCP may provide greater blood flow to the brain and lower body than conventional RCP during HCA in hemiarch surgery.

Partial aortic arch replacement without circulatory arrest: A case study.

Hypothermic circulatory arrest is commonly used during aortic arch surgery. However, it is associated with high risk of visceral organ and lower limb ischemia. There may be advantages to reduction duration of hypothermic circulatory arrest to prevent ischemic complications. We present a case of partial aortic arch replacement without use of hypothermic circulatory arrest.