Deep hypothermic circulatory arrest (DHCA) with antegrade cerebral perfusion has been historically preferred for organ protection during surgical repair of the acute aortic dissection type A. However, in the past decades, different perfusion-specific strategies with a growing trend to increase the body temperature at circulatory arrest emerged. In this study, we retrospectively analyzed the clinical results of our modified protocol for cardiopulmonary bypass and hypothermia management.
Between February 2007 and September 2012, 54 consecutive patients suffering from acute aortic dissection type A underwent emergent surgery. All patients received hypothermic circulatory arrest in combination with antegrade cerebral perfusion. The patients were divided into two subsets according to the degree of hypothermia and perfusion strategies: namely the DHCA group and the group of modified hypothermic circulatory arrest (MHCA).
The overall 30-day mortality was 27.8% and was not significantly different between groups (DHCA, 33.3%, MHCA, 19%; p=0.253). The requirement for blood product transfusion in MHCA patients was significantly less as as compared with the patients in the DHCA group. No difference occurred in the incidence of temporary neurologic dysfunction, dialysis-dependent renal failure, or reexploration for bleeding between two groups of patients. The use of MHCA was identified as a protective factor against the postoperative composite complications (OR, 0.78; CI, 0.52 to 0.98; p=0.04) and the prolonged intensive care unit stay (OR, 0.8; 95% CI, 0.56 to 0.98; p=0.04).
Moderate hypothermia in combination with selective brain perfusion and systemic retrograde perfusion is associated with adequate cerebral and visceral protection, reduced postoperative complications and shortened intensive care unit stay in our series. This modified perfusion strategy may help in improving perioperative outcomes in this particular group of patients.
Acute aortic dissection; Hypothermia; Circulatory arrest; Aortic surgery
Recognizing the importance of neuroprotection in aortic arch surgery, deep hypothermic circulatory arrest (DHCA) now underpins operative practice as it minimizes cerebral metabolic activity. When prolonged periods of circulatory arrest are required, selective antegrade cerebral perfusion (SACP) is supplemented as an adjunct. However, concerns exist over the risks of SACP in introducing embolism and hypo- and hyper-perfusing the brain. The present meta-analysis aims to compare postoperative outcomes in arch surgery using DHCA alone or DHCA + SACP as neuroprotection strategies.
Electronic searches were performed using six databases from their inception to January 2013. Two reviewers independently identified all relevant studies comparing DHCA alone with DHCA + SACP. Data were extracted and meta-analyzed according to pre-defined clinical endpoints.
Nine comparative studies were identified in the present meta-analysis, with 648 patients employing DHCA alone and 370 utilizing DHCA + SACP. No significant differences in temporary or permanent neurological outcomes were identified. DHCA + SACP was associated with significantly better survival outcomes (P=0.008, I2=0%), despite longer cardiopulmonary bypass time. Infrequent and inconsistent reporting of other clinical results precluded analysis of systemic outcomes.
The present meta-analysis indicate the superiority of DHCA + SACP in terms of mortality outcomes.
Deep hypothermic circulatory arrest; antegrade cerebral perfusion; aortic arch surgery; meta-analysis
The use of selective cerebral perfusion with warmer temperatures during circulatory arrest has been increasingly utilized for arch replacement over concerns regarding the safety of deep hypothermic circulatory arrest (DHCA). However, little data actually exists on outcomes following arch replacement and DHCA. This study examines modern results with DHCA for proximal arch replacement to provide a benchmark for comparison against outcomes with lesser degrees of hypothermia.
Between 7/2005–6/2010, 245 proximal arch replacements (“hemi-arch”) were performed using deep hypothermia; mean minimum core and nasopharyngeal temperatures were 18.0±2.1°C and 14.1±1.6°C, respectively. Adjunctive cerebral perfusion was used in all cases. Concomitant ascending aortic replacement was performed in 41%, ascending plus aortic valve replacement in 23%, and aortic root replacement in 32%.
Mean age was 58±14 years; 36% procedures were urgent/emergent. Mean duration of DHCA was 20.4±6.2 minutes. Thirty day/in-hospital mortality was 2.9%. Rates of stroke, renal failure, and respiratory failure were 4.1% (0.8% for elective cases), 1.2%, and 0.4%, respectively.
Deep hypothermia with adjunctive cerebral perfusion for circulatory arrest during proximal arch replacement affords excellent neurologic as well as non-neurologic outcomes. Centers utilizing lesser degrees of hypothermia for arch surgery, the safety of which remains unproven, should ensure comparable results.
aortic surgery; hemi-arch; circulatory arrest; hypothermia; aortic arch
Antegrade cerebral perfusion (ACP) is a cardiopulmonary bypass technique that uses special cannulation procedures to perfuse only the brain during neonatal and infant aortic arch reconstruction. It is used in lieu of deep hypothermic circulatory arrest (DHCA), and thus has the theoretical advantage of protecting the brain from hypoxic ischemic injury. Despite this, recent comparative studies have demonstrated no difference in neurodevelopmental outcomes with ACP vs. DHCA for neonatal arch repair. This article presents animal and human data demonstrating that ACP flows less than 30 ml/kg/min are inadequate for many patients, and may be the explanation for lack of outcome difference vs. DHCA. A technique for ACP, its physiologic basis, and a neuromonitoring strategy are presented, and then the results of an outcome study are reviewed demonstrating that with ACP technique at higher flows of 50–80 ml/kg/min guided by neuromonitoring, periventricular leukomalacia (PVL) is eliminated on postoperative brain MRI after neonatal cardiac surgery.
Correction of ascending aorta and proximal aortic arch pathology with numerous surgical techniques having been proposed over the years remains a surgical challenge. This study was undertaken to identify risk factors influencing outcome after aortic arch operations, requiring deep hypothermic circulatory arrest (DHCA).
Between 1993 and 2010, 207 consecutive patients were operated for ascending aorta and proximal arch correction with the use of deep hypothermic circulatory arrest with retrograde cerebral perfusion. All patients were followed up with regular out-patient clinics, transthoracic echocardiography and, when required, chest computed tomography.
There were 102 (49.3%) emergencies (acute type A dissection) and 105 (50.7%) elective cases. Mean age: 63.5 ± 12 years. Mean circulatory arrest time was 25.4 ± 13 min. Unadjusted analysis of factors associated with 30-day mortality revealed emergency status, preoperative hemodynamic instability, acute dissection, reoperation, increased circulatory arrest time, postoperative bleeding, postoperative creatinine levels and presence of neurological dysfunction. Multi-adjusted analysis revealed duration of circulatory arrest as the only and main factor related to death. Thirty-day mortality was 2.4% for the elective and 7.2% for emergencies cases. Survival during long-term follow-up was 93, 82 and 53% at 1, 5 and 10 years, respectively.
Ascending aorta and proximal aortic arch replacement with brief duration of deep hypothermic circulatory arrest combined with retrograde cerebral perfusion is a safe method with acceptable short- and long-tem results.
Aorta; Aortic arch; Thoracic aorta; Aneurysm; Cardiopulmonary bypass
A robust inflammatory response occurs in the hours and days following cerebral ischemia. However, little is known about the immediate innate immune response in the first minutes after an ischemic insult in humans. We utilized the use of circulatory arrest during cardiac surgery to assess this.
Twelve neonates diagnosed with an aortic arch obstruction underwent cardiac surgery with cardiopulmonary bypass and approximately 30 minutes of deep hypothermic circulatory arrest (DHCA, representing cerebral ischemia). Blood samples were drawn from the vena cava superior immediately after DHCA and at various other time points from preoperatively to 24 hours after surgery. The innate immune response was assessed by neutrophil and monocyte count and phenotype using FACS, and concentrations of cytokines IL-1β, IL-6, IL-8, IL-10, TNFα, sVCAM-1 and MCP-1 were assessed using multiplex immunoassay. Results were compared to a simultaneously drawn sample from the arterial cannula. Twelve other neonates were randomly allocated to undergo the same procedure but with continuous antegrade cerebral perfusion (ACP).
Immediately after cerebral ischemia (DHCA), neutrophil and monocyte counts were higher in venous blood than arterial (P = 0.03 and P = 0.02 respectively). The phenotypes of these cells showed an activated state (both P <0.01). Most striking was the increase in the ‘non-classical’ monocyte subpopulations (CD16intermediate; arterial 6.6% vs. venous 14%; CD16+ 13% vs. 22%, both P <0.01). Also, higher IL-6 and lower sVCAM-1 concentrations were found in venous blood (both P = 0.03). In contrast, in the ACP group, all inflammatory parameters remained stable.
In neonates, approximately 30 minutes of cerebral ischemia during deep hypothermia elicits an immediate innate immune response, especially of the monocyte compartment. This phenomenon may hold important clues for the understanding of the inflammatory response to stroke and its potentially detrimental consequences.
Cardiac surgery; Cerebral blood flow; Hypothermia; Inflammation; Neonatal ischemia; Randomized controlled trials
The purpose of this study was to assess deep hypothermic circulatory arrest (DHCA) as a modifier of neurodevelopmental (ND) outcomes in preschool children after cardiac surgery in infancy for repair of congenital heart defects (CHD).
This is a planned analysis of infants enrolled in a prospective study of apolipoprotein E polymorphisms and ND outcome after cardiac surgery. The effect of DHCA was assessed in patients with single or biventricular CHD without aortic arch obstruction. Neurodevelopmental assessment at 4 years of age included cognition, language, attention, impulsivity, executive function, social competence, and visual-motor and fine-motor skills. Patient and procedural variables were evaluated in univariate and multivariate models.
Neurodevelopmental testing was completed in 238 of 307 eligible patients (78%). Deep hypothermic circulatory arrest was used at the discretion of the surgeon at least once in 92 infants (38.6%) with a median cumulative duration of 36 minutes (range, 1 to 132 minutes). By univariate analysis, DHCA patients were more likely to have single-ventricle CHD (p = 0.013), lower socioeconomic status (p < 0.001), a higher incidence of preoperative ventilation (p < 0.001), and were younger and smaller at the first surgery (p < 0.001). By multivariate analysis, use of DHCA was not predictive of worse performance for any ND outcome.
In this cohort of children undergoing repair of CHD in infancy, patients who underwent DHCA had risk factors associated with worse ND outcomes. Despite these, use of DHCA for repair of single-ventricle and biventricular CHD without aortic arch obstruction was not predictive of worse performance for any ND domain tested at 4 years of age.
Carbon monoxide (CO) at low concentrations imparts protective effects in numerous preclinical small animal models of brain injury. Evidence of protection in large animal models of cerebral injury, however, has not been tested. Neurologic deficits following open heart surgery are likely related in part to ischemia reperfusion injury that occurs during cardiopulmonary bypass surgery. Using a model of deep hypothermic circulatory arrest (DHCA) in piglets, we evaluated the effects of CO to reduce cerebral injury. DHCA and cardiopulmonary bypass (CPB) induced significant alterations in metabolic demands, including a decrease in the oxygen/glucose index (OGI), an increase in lactate/glucose index (LGI) and a rise in cerebral blood pressure that ultimately resulted in increased cell death in the neocortex and hippocampus that was completely abrogated in piglets preconditioned with a low, safe dose of CO. Moreover CO-treated animals maintained normal, pre-CPB OGI and LGI and corresponding cerebral sinus pressures with no change in systemic hemodynamics or metabolic intermediates. Collectively, our data demonstrate that inhaled CO may be beneficial in preventing cerebral injury resulting from DHCA and offer important therapeutic options in newborns undergoing DHCA for open heart surgery.
A recent concern of deep hypothermic circulatory arrest (DHCA) in aortic arch surgery has been its potential association with increased risk of coagulopathy, elevated inflammatory response and end-organ dysfunction. Recently, moderate hypothermic circulatory arrest (MHCA) with selective antegrade circulatory arrest (SACP) seeks to negate potential hypothermia-related morbidities, while maintaining adequate neuroprotection. The present meta-analysis aims to compare postoperative outcomes in arch surgery using DHCA or MHCA+SACP as neuroprotective strategies.
Electronic searches were performed using six databases from their inception to January 2013. Two reviewers independently identified all relevant studies comparing DHCA with MHCA+SACP, as defined by a recent hypothermia temperature consensus. Data were extracted and meta-analyzed according to pre-defined clinical endpoints.
Nine comparative studies were identified for inclusion in the present meta-analysis. Stroke rates were significantly lower in patients undergoing MHCA+SACP (P=0.0007, I2=0%), while comparable results were observed with temporary neurological deficit, mortality, renal failure or bleeding. Infrequent and inconsistent reporting of systemic outcomes precluded analysis of other systemic outcomes.
The present meta-analysis indicated the superiority of MHCA+SACP in terms of stroke risk.
Deep hypothermic circulatory arrest; moderate hypothermic circulatory arrest; antegrade cerebral perfusion; meta-analysis
Massive perioperative blood product transfusion may be required with thoracic aortic operations and is associated with poor outcomes. Our objective was to determine the independent predictors of massive transfusion in thoracic aortic surgery patients undergoing deep hypothermic circulatory arrest (DHCA).
The study consisted of 168 consecutive patients undergoing open thoracic aortic procedure utilizing DHCA between July 2005 and August 2008. We identified 26 preoperative and procedural variables as being potentially related to blood product usage. We tested the variables for association with total blood products transfused using a multivariate linear regression model and then constructed a logistic regression model for massive transfusion, defined as requiring 5 or more units of transfused packed red blood cells between incision and 48 hours postoperatively.
Multivariate linear regression determined six significant variables as accounting for 42% of the variation in total blood products transfused: age (P=0.008), preoperative hemoglobin (P=0.04), weight (P=0.02), cardiopulmonary bypass time (P<0.0001), emergent status (P<0.0001), and re-do median sternotomy (P<0.0001). A final predictive logistic regression model associated every 1 g/dL increase in preoperative hemoglobin OR=0.54 [0.43, 0.69], P<0.0001; every 10 minute increase in CPB time, OR=1.15 [1.05, 1.26], P=0.0026; and emergent status OR=4.02 [1.53, 10.55], P=0.0047 with massive transfusion.
Our model described CPB time, emergent status, and preoperative hemoglobin as independent predictors of massive transfusion. These variables, along with weight, age, and re-do median sternotomy are associated with total blood product usage in thoracic aortic operations involving DHCA.
Antegrade cerebral perfusion makes deep hypothermia non-essential for neuroprotection; therefore, there is a growing tendency to increase the body temperature during circulatory arrest with selective brain perfusion. However, very little is known about the clinical efficacy of mild-to-moderate hypothermia for ischemic organ protection during circulatory arrest. The aim of this study was to evaluate the safety and efficiency of mild-to-moderate hypothermia for lower-body protection during aortic arch surgery with circulatory arrest and antegrade cerebral perfusion.
Between January 2005 and December 2009, a total of 347 patients underwent non-emergent arch surgery. In all patients, the systematic cooling was adapted to the expected time of circulatory arrest, and cerebral perfusion was performed at a constant blood temperature of 28 °C. There were 40 cardiac or aortic re-operations, 312 patients had concomitant aortic valve or root surgery, and 10 patients had replacement of the descending aorta. All examined data were collected prospectively.
The duration of circulatory arrest and the deepest rectal temperature were 18 ± 11 min (range, 6–70 min) and 31.5 ± 1.6 °C (range, 26.0–35.0 °C) for all 347 patients, and 34 ± 12 min (range, 17–70 min) and 29.9 ± 1.7 °C (range, 26.0–34.6 °C) for 77 patients having total/subtotal arch replacement. The maximum serum lactate level on the first postoperative day was, on average, 2.3 ± 1.2 mmol l−1. In the statistical analysis, no association between the duration of temperature-adapted circulatory arrest and lactate, creatinine, or lactate dehydrogenase levels after surgery could be demonstrated. The 30-day mortality was 0.9%. Permanent neurological deficit or temporary dysfunction occurred in three (0.9%) and eight (2.3%) patients, respectively. No paraplegia and no hepatic failure were reported; however, mesenteric ischemia occurred in one patient with severe stenosis of the celiac and upper mesenteric arteries. Temporary dialysis was necessary primarily after surgery in five patients. All of them underwent hemiarch replacement only, and four patients had an increased creatinine level before surgery.
Systemic mild-to-moderate hypothermia that is adapted to the duration of circulatory arrest is a simple, safe, and effective method of organ protection and can be recommended in routine aortic arch surgery with circulatory arrest and cerebral perfusion.
Aortic arch; Circulatory arrest; Hypothermia; Organ protection
Deep hypothermic circulatory arrest for adult aortic arch repair is still associated with significant mortality and morbidity. Furthermore, there is still significant variation in the conduct of this complex perioperative technique. This variation in deep hypothermic circulatory arrest practice has not been adequately characterized and may offer multiple opportunities for outcome enhancement. The hypothesis of this study was that the current practice of adult deep hypothermic circulatory arrest in China has significant variations that might offer therapeutic opportunities for reduction of procedural risk.
An adult deep hypothermic circulatory arrest questionnaire was developed and then administered at a thoracic aortic session at the International Cardiothoracic and Vascular Anesthesia Congress convened in Beijing during 2010. The data was abstracted and analyzed.
The majority of the 56 respondents were anesthesiologists based in China at low-volume deep hypothermic circulatory arrest centers. The typical aortic arch repair had a prolonged deep hypothermic circulatory arrest time at profound hypothermia. The target temperature for deep hypothermic circulatory arrest was frequently measured distal to the brain. The most common perfusion adjunct was antegrade cerebral perfusion, typically monitored with radial arterial pressure and cerebral venous oximetry. The preferred neuroprotective agents were steroids and propofol.
The identified opportunities for outcome improvement in this delineated deep hypothermic circulatory arrest model include nasal/tympanic temperature measurement and routine cerebral perfusion, preferably with unilateral antegrade cerebral perfusion monitored with radial artery pressure and cerebral oximetry. Development and dissemination of an evidence-based consensus would enhance these practice-improvement opportunities.
adult aortic arch repair; deep hypothermic circulatory arrest; China; temperature monitoring; retrograde cerebral perfusion; antegrade cerebral perfusion; steroids; propofol; neuroprotection; cerebral oximetry; questionnaire; practice variation; radial artery pressure; cardiopulmonary bypass
Safe limits of time and temperature during sleep hypothermic
circulatory arrest (DHCA) still remain controversial. Furthermore,
continuous changes of PaO2, PaCO2, and pH have never been measured during
DHCA in humans. Continuous intraarterial blood gas (CIABG) monitoring is a
new technology allowing us to study chronological changes occurring due to
metabolism during DHCA. When the patients' temperature reached 18
approximately 20 degrees C following establishment of cardiopulmonary bypass
(CPB), circulatory arrest was initiated. After a 20-minute period of DHCA,
reperfusion commenced with 18 degree C blood. We continuously monitored
PaO2, PaCO2, and pH immediately before, during and following DHCA. Data was
analyzed by Student's t-test. PaO2, PaCO2, and pH of pre- and 5 minutes post
DHCA were not significantly different from each other. However, during DHCA,
the PaO2 was significantly decreased from 229 +/- 34 to 30 +/- 23 mmHg at
20-minute intervals. But the PaCO2 increased significantly after 20 minutes
of circulatory arrest from 34 +/- 5 to 42 +/- 6 mmHg. However, the pH did
not change significantly over the 20-minute period. The PaO2 level after 20
minutes is much lower than before DHCA, it would be well tolerated in
normothermic adults. The PO2 level in the brain may be even lower given its
high metabolic rate. So measuring arterial PO2 continuously during DHCA may
provide a surrogate method for determining maximum safe time under DHCA for
Aortic arch reconstruction is associated with high neurological morbidity. Our purpose is to describe our experience using a 4-branched graft and selective antegrade brain perfusion (SABP) for total aortic arch replacement (TAR).
We retrospectively reviewed the medical records of 12 patients who received TAR, with or without ascending aorta replacement, with a 4-branched graft for Stanford type A dissection (n = 9) or aortic arch aneurysm (n = 3). In all patients surgery was performed with deep hypothermic circulatory arrest (DHCA) with or without retrograde brain perfusion, and selective antegrade brain perfusion (SABP) via the subclavian artery or axillary artery.
There were 8 males and 4 females with an average age of 63.14 years. Emergent operations were performed in 9 patients with acute type A aortic dissections. Of all 12 patients, 2 deaths occurred and 1 patient experienced lower extremity paraplegia resulting in an in-hospital mortality rate of 16.6% and a permanent neurological deficit rate of 8.3%.
The use of a 4-branched graft, hypothermic circulatory arrest, and SABP is a useful operative method for aortic arch replacement with acceptable morbidity and mortality.
Aortic arch aneurysm; Type A aortic dissection; Branched aortic graft
A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: Is it worth packing the head with ice in patients undergoing deep hypothermic circulatory arrest (DHCA)? Altogether more than 34 papers were found using the reported search, of which 7 represented the best evidence to answer the clinical question, 5 of which were animal studies, 1 was a theoretical laboratory study and 1 study looked at the ability to cool using circulating water ‘jackets’ in humans. There were no available human studies looking at the neurological outcome with or without topical head cooling with ice without further adjunct methods of cerebral protection. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Four papers studied animals undergoing DHCA for 45 min–2 h depending on the study design, with or without packing the head with ice. The studies all demonstrated improved cerebral cooling when the head was packed with ice during DHCA. They also illustrated an improved neurological outcome, with better behavioural scores (P < 0.05), and in some, survival, when compared with animals whose heads were not packed in ice. One study examined selective head cooling with the use of packing the head with ice during rewarming after DHCA. However, they demonstrated worse neurological outcomes in these animals, possibly due to the loss of cerebral vasoregulation and cerebral oedema. One study involved a laboratory experiment showing improved cooling using circulating cool water in cryotherapy braces than by using packed ice. They extrapolated that newer devices to cool the head may improve cerebral cooling during DHCA. The final study discussed here demonstrated the use of circulating water to the head in humans undergoing pulmonary endarterectomy. They found that tympanic membrane temperatures could be maintained significantly lower than bladder or rectal temperatures when using circulating water to cool the head. We conclude that topical head cooling with ice is of use during DHCA but not during rewarming following DHCA and that it may be possible to advance topical head cooling techniques using circulating water rather than packed ice.
Deep hypothermic circulatory arrest; Topical cooling; Head cooling; Topical hypothermia
Effective cerebral protection remains the principle concern during aortic arch surgery. Hypothermic circulatory arrest (HCA) is entrenched as the primary neuroprotection mechanism since the 70s, as it slows injury-inducing pathways by limiting cerebral metabolism. However, increases in HCA duration has been associated with poorer neurological outcomes, necessitating the adjunctive use of antegrade (ACP) and retrograde cerebral perfusion (RCP). ACP has superseded RCP as the preferred perfusion strategy as it most closely mimic physiological perfusion, although there exists uncertainty regarding several technical details, such as unilateral versus bilateral perfusion, flow rate and temperature, perfusion site, undue trauma to head vessels, and risks of embolization. Nevertheless, we believe that the convenience, simplicity and effectiveness of straight DHCA justifies its use in the majority of elective and emergency cases. The following perspective offers a historical and clinical comparison of the DHCA with other techniques of cerebral protection.
Deep hypothermic circulatory arrest; aortic arch surgery; cerebral perfusion; neuroprotection
Pulmonary endarterectomy is the treatment of choice in suitable patients who have chronic thromboembolic pulmonary hypertension. The most common surgical technique involves the use of deep hypothermic circulatory arrest. Herein, we describe a modified aortic clamping technique with selective antegrade cerebral perfusion, performed with moderate hypothermia but without circulatory arrest. This technique avoids the adverse effects of deep hypothermic circulatory arrest and also establishes a bloodless surgical field. We achieved good surgical results and acceptable long-term outcomes in 3 patients with use of this technique, which we recommend as a feasible alternative to the standard operative practice.
Circulatory arrest, deep hypothermia-induced; endarterectomy; hypertension, pulmonary; pulmonary artery; risk factors
Cerebral protection and circulatory management remains a controversial issue in aortic arch surgery. The present study reported surgical outcomes of arch repair using moderate hypothermic circulatory arrest (MHCA) and unilateral selective antegrade perfusion (uSACP).
From January 2004 and December 2012, 500 patients underwent hemiarch repair (HARCH) and 124 underwent total arch replacement (TARCH) utilizing moderate hypothermic circulatory arrest with unilateral selective antegrade cerebral perfusion of the right axillary artery. Emergent surgery was required in 142 (28.4%) of HARCH patients and 18 (14.5%) of TARCH patients. Mean arrest temperature ranged from 25.6-27.2 °C for elective and emergent operations in both groups. Mean circulatory arrest was 26.8 minutes for hemiarch repairs and 54.2 minutes for total arch replacement.
Overall mortality was 6.6% for hemiarch repairs and 9.7% for total arch replacements. Hospital mortality was 4.5% (16/358) and 10.4% (11/106) in elective cases, and 12% (17/142) and 5.6% (1/18) in elective cases, for hemiarch and total arch replacements respectively. Permanent neurological deficit (PND) occurred in 3 total arch replacement cases (2.4%). Multivariate analysis demonstrated that temperature was not found to be an independent risk factor during hemiarch or total arch replacements for mortality, permanent or neurological deficits, or renal failure.
Our approach for hemiarch and total arch repair utilizing MHCA and uSACP via the right axillary artery was associated excellent neurological and survival outcomes. Moderate hypothermia did not adversely impact cerebral or visceral organ protection.
Aortic arch surgery; moderate hypothermic circulatory arrest; hemiarch repair; total arch replacement; retrospective study
Brain protection during aortic arch surgery by perfusing cold oxygenated blood into the superior vena cava was first reported by Lemole et al. In 1990 Ueda and associates first described the routine use of continuous retrograde cerebral perfusion (RCP) in thoracic aortic surgery for the purpose of cerebral protection during the interval of obligatory interruption of anterograde cerebral flow. The beneficial effects of RCP may be its ability to sustain brain hypothermia during hypothermic circulatory arrest (HCA) and removal of embolic material from the arterial circulation of the brain. RCP can offer effective brain protection during HCA for about 40 to 60 minutes. Animal experiments revealed that RCP provided inadequate cerebral perfusion and that neurological recovery was improved with selective antegrade cerebral perfusion (ACP), however, both RCP and ACP provide comparable clinical outcomes regarding both the mortality and stroke rates by risk-adjusted and case-matched comparative study. RCP still remains a valuable adjunct for brain protection during aortic arch repair in particular pathologies and patients.
Aortic arch surgery; brain protection; retrograde cerebral perfusion; hypothermic circulatory arrest
To compare the effects of pH-stat and alpha-stat management prior to deep hypothermic circulatory arrest (DHCA) followed by a period of low flow (two rates) cardiopulmonary bypass (CPB) on cortical oxygenation and selected regulatory proteins: Bax, Bcl-2, Caspase-3 and phospho-Akt.
Piglets were placed on CPB, cooled with pH-stat or alpha-stat management to 18°C over 30 min, subjected to 30 min DHCA and 1h low flow at 20 (LF-20) or 50 ml/kg/min (LF-50), rewarmed to 37°C, separated from CPB, and recovered for 6 h.
Newborn piglets, 2–5 days old, randomly assigned to experimental groups.
Measurements and main results
Cortical oxygen was measured by oxygen-dependent quenching of phosphorescence; proteins were measured by western blots. The means from 6 experiments ± standard error (SEM) are presented as % of alpha-stat. Significance was by t-test. For LF-20, cortical oxygenation was similar for alpha-stat and pH-stat, whereas for LF-50 it was significantly better using pH-stat. For LF-20, the measured proteins were not different except for Bax in the cortex (214±24%, p=0.006) and hippocampus (118% ± 6%, p=0.024) and Caspase 3 in striatum (126% ± 7%, p=0.019). For LF-50, in pH-stat group: In cortex, Bax and Caspase-3 were lower (72±8%, p=0.001 and 72±10%, p=0.004, respectively) and pAkt was higher (138±12%, p=0.049). In hippocampus, Bcl-2 and Bax were not different but pAkt was higher 212±37% (p=0.005) and Caspase 3 lower (84 ± 4%, p=0.018). In striatum, Bax and pAkt did not differ but Bcl-2 increased (146±11%, p=0.001) and Caspase-3 decreased (81±11%, p=0.042).
In this DHCA-LF model, when flow was 20ml/kg/min there was little difference between alpha-stat and pH-stat management. However for LF-50, pH-stat management resulted in better cortical oxygenation during recovery and Bax, Bcl-2, pAkt and Caspase-3 changes consistent with lesser activation of pro-apoptotic signaling with pH-stat than with alpha-stat.
Cardiopulmonary bypass; Circulatory arrest; alpha-stat; pH-stat; Oxygen; Apoptosis
Since the pioneering work of DeBakey, Cooley, and colleagues more than 50 years ago, surgical treatment of aneurysms involving the transverse aortic arch has been associated with substantial morbidity and mortality. Over the past 15 years, techniques for replacing the diseased aortic arch have evolved substantially. Previously, our approach to these operations involved femoral cannulation, profound-to-deep hypothermic circulatory arrest and retrograde cerebral perfusion, and the island technique for reattaching the brachiocephalic vessels. In contrast, we currently use innominate artery cannulation, deep-to-moderate hypothermic circulatory arrest with antegrade cerebral perfusion, bilateral cerebral monitoring with near-infrared spectroscopy, and the trifurcated graft (Y-graft) technique for reattaching the arch branches. Cannulating the innominate artery to provide an inflow site for cardiopulmonary bypass has facilitated the use of antegrade cerebral perfusion as a cerebral protection strategy; the left common carotid artery is additionally perfused to provide bilateral cerebral perfusion. Despite having a systemic circulatory arrest time that often exceeds 60 minutes, these improved perfusion strategies make it possible to consistently avoid cerebral circulatory arrest all together. A moderate temperature target of between 18 and 23 °C is now used; this appears to reduce the risk of hypothermic coagulopathy and improve hemostasis. Y-graft techniques, such as the trifurcated graft approach, have the advantages of eliminating residual aortic arch tissue and being easily tailored to the needs of the individual patient. This report describes total aortic arch replacement in patients with aneurysms that are confined to the ascending aorta and transverse aortic arch.
Aortic arch surgery; total arch replacement; trifurcated graft
Aortic arch surgery remains a complex surgical operation that necessitates specific neuroprotection strategies. Various approaches, such as hypothermic circulatory arrest (HCA), retrograde cerebral perfusion, and antegrade selective cerebral perfusion (aSCP), have each enjoyed periods of popularity. However, while the overall surgical approach tend to favour HCA with aSCP, technical factors, such as perfusion site, perfusate temperature and flow rate and pH management, have not been conclusively elucidated. The optimal extent of hypothermia during circulatory arrest is also unclear, particularly with recent partiality for warmer temperatures. The following perspective details the preferred surgical practice for cerebral protection in aortic arch surgery, based on existing evidence.
Aortic arch surgery; hypothermic circulatory arrest; selective antegrade cerebral perfusion; cerebral protection
A 50-year-old man, who 9 months earlier had undergone emergency operation for acute type I aortic dissection, was readmitted to our hospital with the diagnosis of an enlarging aneurysm of the false lumen involving the transverse arch and the proximal third of the descending thoracic aorta, due principally to redissection at the distal suture line of the ascending aortic graft. Replacement of the aortic arch and proximal descending thoracic aorta was performed by using the retrograde "pull-through" technique with hypothermic circulatory arrest and retrograde cerebral perfusion. Although circulatory arrest lasted 110 minutes, the patient was extubated on the 2nd postoperative day and had no central or peripheral neurologic damage. Mild, transitory renal dysfunction was observed in the 1st postoperative week, and the patient was discharged on the 18th postoperative day. He is asymtomatic at 15 postoperative months. Deep hypothermia and retrograde cerebral perfusion proved effective despite prolonged circulatory arrest. The retrograde "pull-through" technique is an effective method of replacing the entire thoracic aorta and should probably be considered for single-stage repair of acute type I aortic dissection with multiple intimal tears.
Anesthetic management for aortic arch aneurysm (AAA) surgery employing deep hypothermic circulatory arrest in a Jehovah's Witness (JW) patient is a challenge to anesthesiologist due to its complexity of procedures and their refusal of allogeneic transfusion. Even in the strict application of intraoperative acute normovolemic hemodilution (ANH) and intraopertive cell salvage (ICS) technique, prompt timing of re-administration of salvaged blood is essential for successful operation without allogeneic transfusion or ischemic complication of major organs. Cerebral oximetery (rSO2) monitoring using near infrared spectroscopy is a useful modality for detecting cerebral ischemia during the AAA surgery requiring direct interruption of cerebral flow. The present case showed that rSO2 can be used as a trigger facilitating to find a better timing for the re-administration of salvaged blood acquired during the AAA surgery for JW patient.
Aortic arch aneurysm; Cerebral oximetry; Jehovah's Witness
We retrospectively report the first use of intrathecal morphine prior to incision in two male patients undergoing a complex aortic reconstruction, who required complete circulatory arrest under deep hypothermia for intraoperative and postoperative pain control. We administered intrathecal morphine to two male patients undergoing circulatory arrest and deep hypothermia. Patients were fully heparinized prior to cardiopulmonary bypass. Deep hypothermic circulatory arrest was performed by cooling the patients to 18℃. Following the surgery, the neurologic status was monitored. The management of postoperative pain is a quality standard in health care. During the first 24 hours after surgery, we observed excellent analgesia without the associated side effects, thus, reducing the time required for pain control by the nursing staff. A successful analgetic strategy not only enhances the patient satisfaction, but may improve the postoperative outcome. However, complications, such as increased risk of epidural hematoma formation, are of special concern in cardiac surgery.
Cardiac surgical procedures; Circulatory arrest (hypothermia induced); Morphine; Spinal anesthesia