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.
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.
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
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
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
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
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
Electroencephalographic seizures have been shown to occur in 5% to 20% of neonates and infants after biventricular repair of a variety of cardiac defects. Occurrence of a seizure is a predictor of adverse long-term neurodevelopmental sequelae. The contemporary incidence of postoperative seizures after repair of cardiac defects such as hypoplastic left heart syndrome and other forms of single ventricle is not known.
A prospective study of 178 patients less than 6 months of age undergoing cardiopulmonary bypass with or without deep hypothermic circulatory arrest (DHCA) was conducted at a single institution from September 2001 through March 2003 to identify postoperative seizures assessed by 48-hour continuous video electroencephalographic monitoring.
Cardiac defects included transposition of the great arteries with or without a ventricular septal defect (n = 12), ventricular septal defect with or without coarctation (n = 28), tetralogy of Fallot (n = 24), hypoplastic left heart syndrome or variant (n = 60), other functional single ventricle (n = 14), and other defects suitable for biventricular repair (n = 40). Median age at the time of the operation was 7 days (range, 1–188 days) and was 30 days or less in 110 (62%) patients. DHCA was used in 117 (66%) patients, with multiple episodes in 9 patients. Median total duration of DHCA was 40 minutes (range, 1–90 minutes). Electroencephalographic seizures were identified in 20 (11.2%) patients. Seizures occurred in 15 (14%) of 110 neonates and 5 (7%) of 68 older infants. Seizures occurred in 1 (4%) of 24 patients with tetralogy of Fallot, 1 (8%) of 12 with transposition of the great arteries, and 11 (18%) of 60 with hypoplastic left heart syndrome or variant. By stepwise logistic regression analysis, once increasing duration of total DHCA (P = .001) was considered, no other variable improved prediction of occurrence of a seizure. Patients with DHCA duration of more than 40 minutes had an increased incidence of seizures (14/58 [24.1%]) compared with those with a DHCA duration of 40 minutes or less (4/59 [6.8%], P = .04). The incidence of seizures for patients with a DHCA duration of 40 minutes or less was not significantly different from those in whom DHCA was not used (2/61 [3.3%], P = .38).
In the current era, continuous electroencephalographic monitoring demonstrates early postoperative seizures in 11.2% of a heterogeneous cohort of neonates and infants with complex congenital heart defects. Increasing duration of DHCA was identified as a predictor of seizures. However, the incidence of seizures in children with limited duration of DHCA was similar to that in infants undergoing continuous cardiopulmonary bypass alone.
To determine the effect of pH-stat as compared with alpha-stat management on brain oxygenation, level of striatal extracellular dopamine, phosphorylation, and levels of protein kinase B (Akt) and cyclic adenosine 3’, 5’-monophosphate response element-binding protein (CREB), and levels of extracellular signal-regulated kinase (ERK)1/2, Bcl-2, and Bax in a piglet model of deep hypothermic circulatory arrest (DHCA).
The piglets were placed on cardiopulmonary bypass (CPB), cooled with pH-stat or alpha-stat to 18°C, subjected to 90 minutes of DHCA, rewarmed, weaned from CPB, and maintained for two hours recovery. The cortical oxygen was measured by: quenching of phosphorescence; dopamine by microdialysis; phosphorylation of CREB (p-CREB), ERK (p-ERK) 1/2, Akt (p-Akt), and level of Bcl-2, Bax by Western blots.
Oxygen pressure histograms for the microvasculature of the cortex show substantially higher oxygen levels during cooling and during the oxygen depletion period after cardiac arrest (up to 15 minutes) when using pH-stat compared with alpha-stat management. Significant increases in dopamine occurred at 45 minutes and 60 minutes of DHCA in the alpha-stat and pH-stat groups, respectively. The p-CREB and p-Akt in the pH-stat group were significantly higher than in the alpha-stat group (140 ± 9%, p < 0.05 and 125 < 6%, p < 0.05, respectively). There was no significant difference in p-ERK1/2 and Bax. The Bcl-2 increased in the pH-stat group to 121 ± 4% (p < 0.05) compared with the alpha-stat group. The ratio Bcl-2:Bax increased in the pH-stat group compared with the alpha-stat group.
The increase in p-CREB, p-Akt, Bcl-2, Bcl-2/Bax, and delay in increase of dopamine indicated that pH-stat, in the piglet model, prolongs “safe” time of DHCA and provides some brain protection against ischemic injury.
We performed this study to determine whether brief intermittent periods of low-flow cardiopulmonary bypass during deep hypothermic circulatory arrest would improve cortical metabolic status and prolong the “safe” time of deep hypothermic circulatory arrest.
After a 2-hour baseline, newborn piglets were placed on cardiopulmonary bypass and cooled to 18°C. The animals were then subjected to 80 minutes of deep hypothermic circulatory arrest interrupted by 5-minute periods of low-flow cardio-pulmonary bypass at either 20 mL · kg−1 · min−1 (LF-20) or 80 mL · kg−1 · min−1 (LF-80) during 20, 40, 60, and 80 minutes of deep hypothermic circulatory arrest. All animals were rewarmed, separated from cardiopulmonary bypass, and maintained for 2 hours (recovery). The oxygen pressure in the cerebral cortex was measured by the quenching of phosphorescence. The extracellular dopamine level in the striatum was determined by microdialysis. Results are means ± SD.
Prebypass oxygen pressure in the cerebral cortex was 65 ± 7 mm Hg. During the first 20 minutes of deep hypothermic circulatory arrest, cortical oxygen pressure decreased to 1.3 ± 0.4 mm Hg. Four successive intermittent periods of LF-20 increased cortical oxygen pressure to 6.9 ± 1.2 mm Hg, 6.6 ± 1.9 mm Hg, 5.3 ± 1.6 mm Hg, and 3.1 ± 1.2 mm Hg. During the intermittent periods of LF-80, cortical oxygen pressure increased to 21.1 ± 5.3 mm Hg, 20.6 ± 3.7 mm Hg, 19.5 ± 3.95 mm Hg, and 20.8 ± 5.5 mm Hg. A significant increase in extracellular dopamine occurred after 45 minutes of deep hypothermic circulatory arrest alone, whereas in the groups of LF-20 and LF-80, the increase in dopamine did not occur until 52.5 and 60 minutes of deep hypothermic circulatory arrest, respectively.
The protective effect of intermittent periods of low-flow cardiopulmonary bypass during deep hypothermic circulatory arrest is dependent on the flow rate. We observed that a flow rate of 80 mL · kg−1 · min−1 improved brain oxygenation and prevented an increase in extracellular dopamine release.
We report the case of a 69-year-old man who presented with a symptomatic mycotic aneurysm of the aortic arch. Diagnosis was confirmed by positron emission tomography and by blood cultures positive for Salmonella species. A complete resection of the aortic arch process was performed via left thoracotomy using a cryopreserved aortic homograft and normothermic left heart bypass. The left-sided cerebral vessels were clamped, and adequacy of collateral left brain flow and oxygenation was confirmed by neurophysiologic monitoring. Using this less-invasive operative strategy, we avoided the risks inherent to deep hypothermic circulatory arrest and the use of prosthetic materials.
Aneurysm, infected/pathology/surgery; aorta, thoracic/surgery; aortic aneurysm, thoracic/complications/surgery; cardiac surgical procedures; monitoring, intraoperative/methods; spectroscopy, nearinfrared; ultrasonography, Doppler, transcranial
OBJECTIVES—Critical vascular surgery of the brain
or the heart occasionally requires total cessation of the circulatory
system. Profound hypothermia is used to protect the brain from
ischaemic injury. This study explores the use of microdialysis to
measure metabolic indices of ischaemia: glutamate, lactate, and pH, and
cerebral temperature during profound hypothermia and circulatory arrest.
METHODS—Effluent from a microdialysis catheter
placed in the cerebral cortex of three patients undergoing complete
circulatory arrest was continuously sampled. Samples were pooled over
10 minute periods and glutamate and lactate concentrations were
measured postoperatively. Brain temperature and pH were measured on
line intraoperatively. Electroencephalography and monitoring of
somatosensory evoked potentials and brainstem auditory evoked
potentials were simultaneously carried out.
RESULTS—Patient 1 had normal glutamate and
lactate. PH was 6.75 to 6.85 and increased to 6.9 after warming ensued.
Patient 2 had raised glutamate and lactate during most measurements.
The glutamate concentrations peaked at 305 µM/l at the start of the
measurements and fell below 20 µM/l after warming. The lactate
concentrations peaked at 680 µM/l before cooling, rose to 1040 µM/l
during the cooling process, decreased to 212 µM/l during circulatory
arrest, and rose again to 620 µM/l after warming. The pH started at
7.06and continued a downward course until stabilising at a pH of 6.5after circulatory arrest. Patient 3 had a transient, mild increase in
glutamate and lactate during the cooling and warming period. pH was
with temperature and pH measurements of the cerebral cortex
promises to be an important tool in detecting cerebral ischaemia.
Further studies are needed to validate our findings and test the
feasibility of modifying ischaemic changes.
We describe a new surgical technique adopted for the repair of Stanford type A aortic dissection. In order to minimize the risk of malperfusion caused by retrograde flow during cardiopulmonary bypass, we avoid femoral artery cannulation. On the hypothesis that it is best not to interfere with the hemodynamics of the dissection, we cannulate the dissected ascending aorta, in either the true or false lumen. We here report 2 cases of successful surgical treatment of Stanford type A aortic dissection. In both cases, the false lumen was cannulated under deep hypothermic circulatory arrest, without clamping the aorta. While the patient was cooling, a 10-mm GORE-TEX side arm was sutured to a Dacron graft prosthesis. Repair of the aortic arch was carried out 1st. The aortic cannula was inserted into the GORE-TEX side arm, the tubular prosthesis was cross-clamped, and cardiopulmonary bypass was reinstituted. After this, the aortic bulb was repaired as usual and the tubular prosthesis was sutured to the bulb. No postoperative cerebral complication occurred. Our experience must be confirmed by more cases and a longer follow up.
Previously, we identified 14-3-3 β and ζ isoforms and proteolytic fragments of α-spectrin as proteins released from degenerating neurons that also rise markedly in cerebrospinal fluid (CSF) following experimental brain injury or ischemia in rodents, but these proteins have not been studied before as potential biomarkers for ischemic central nervous system injury in humans. Here we describe longitudinal analysis of these proteins along with the neuron-enriched hypophosphorylated neurofilament H (pNFH) and the deubiquitinating enzyme UCH-L1 in lumbar CSF samples from 19 surgical cases of aortic aneurysm repair, 7 involving cardiopulmonary bypass with deep hypothermic circulatory arrest (DHCA). CSF levels of the proteins were near the lower limit of detection by Western blot or enzyme-linked fluorescence immunoassay at the onset of surgical procedures, but increased substantially in a subset of cases, typically within 12–24 hours. All cases involving DHCA were characterized by >3-fold elevations in CSF levels of the two 14-3-3 isoforms, UCH-L1, and pNFH. Six of 7 also exhibited marked increases in α-spectrin fragments generated by calpain, a protease known to trigger necrotic neurodegeneration. Among cases involving aortic cross-clamping but not DHCA, the proteins rose in CSF preferentially in the subset experiencing acute neurological complications. Our results suggest the neuron-enriched 14-3-3β, 14-3-3ζ, pNFH, UCH-L1, and calpain-cleaved α-spectrin may serve as a panel of biomarkers with clinical potential for the detection and management of ischemic central nervous system injury, including for mild damage associated with surgically-induced circulation arrest.
ischemia; acute CNS damage; surrogate marker; calpain; circulation arrest
The traumatic rupture of the thoracic aorta is a severe and life-threatening entity. The incidence of penetrating trauma to the aortic arch is not known, because most patients die of haemorrhage even before they receive adequate treatment. Clinical signs of such injuries include external or internal haemorrhage, bruit, distal pulse deficit, neurological deficit and shock. We present a 42-year old female with a penetrating aortic arch injury successfully repaired using deep hypothermic circulatory arrest and retrograde cerebral perfusion.
Aortic arch; Aortic trauma; Deep hypothermic circulatory arrest; Retrograde cerebral perfusion
We describe the performance, in one surgical session, of bilateral pulmonary endarterectomy and a button-technique Bentall operation in a 68-year-old man. The patient had chronic thromboembolic pulmonary hypertension and an ascending aortic aneurysm with moderate aortic regurgitation. The procedures were concurrently completed during short periods of systemic circulatory arrest, with antegrade cerebral perfusion maintained through the brachiocephalic artery at a flow rate of 10 mL/min/kg. The patient's cerebral perfusion was monitored with use of near-infrared spectroscopy, to prevent symmetric bilateral values from falling below 20% of the base value. The patient experienced no multiorgan failure or neurologic sequelae and, by the 6th postoperative day, improved from New York Heart Association functional class IV to class I.
The reliable maintenance of continuous antegrade cerebral perfusion made the lengthy combined operation feasible, with low risk. The use of near-infrared spectroscopy enabled real-time monitoring of the patient's cerebral blood flow. Our experience shows the possibility of safely performing lengthy or multiple procedures in one surgical session.
Brain ischemia/prevention & control; cardiac surgical procedures; endarterectomy/adverse effects/methods; hypertension, pulmonary/physiopathology/surgery; perfusion/methods; pulmonary artery/surgery; recovery of function; treatment outcome
In neonates, the major obstacle to transfusion-free complex cardiac surgery is the severe hemodilution that can result from the mismatch between the priming volume of the circuit and the patients' blood volume. Herein, we report the case of a 13-day-old, 2.96-kg preterm neonate who had a hypoplastic aortic arch and atrial and ventricular septal defects. At the insistence of her Jehovah's Witness parents, we performed corrective surgery without transfusing homologous blood products—using deep hypothermic circulatory arrest in the process. A specially designed cardiopulmonary bypass circuit with a priming volume of only 95 mL was the key component of an interdisciplinary effort to avoid transfusion while maintaining the patient's safety. To our knowledge, this is the 1st report of the use of deep hypothermic circulatory arrest in blood-transfusion–free surgery to correct congenital heart defects in a small Jehovah's Witness neonate.
Blood transfusion, autologous/contraindications; cardiac surgical procedures/methods; cardiopulmonary bypass/instrumentation/methods; heart defects, congenital/surgery; infant, newborn; intraoperative care; Jehovah's Witnesses; miniaturization; treatment outcome; treatment refusal
Leiomyosarcomas typically originate within smooth muscle cells. Leiomyosarcomas arising from the adrenal vein are rare malignancies associated with delayed diagnosis and poor prognosis. The most common vascular site of origin is the inferior vena cava.
This is a 64-year old woman who presented with a 13 × 6.5 × 6.6 cm heterogeneous mass arising in the region of the right adrenal gland and extending into the inferior vena cava (IVC) and the right atrium. Biochemical evaluation excluded a functional tumor of the adrenal gland, and multiple tumor markers were negative. We present the novel use of deep hypothermic circulatory arrest (DHCA) in the resection of an adrenal vein leiomyosarcoma extending into the right atrium. The patient remains free of disease ten months after surgery. DHCA afforded a bloodless operative field for optimal resection of disease from within the IVC.
The diagnosis of leiomyosarcomas of the adrenal vein is one of exclusion and involves preoperative radiological imaging and biochemical evaluation to exclude other functional tumors of the adrenal gland. Aggressive surgical resection is associated with improved survival and may be best achieved via collaboration among different surgical subspecialties.
Antegrade selective cerebral perfusion in conjunction with hypothermia attenuate postoperative neurological injury, which in turn still remains the main cause of mortality and morbidity following aortic arch surgery. Hypothermic circulatory arrest however could be a useful tool during arch surgery, surgery for chronic thromboembolic disease, air on the arterial line during CPB, during cavotomy for extraction of renal cell carcinoma with level IV extension, or when dealing with difficult trauma to the SVC or IVC. Cerebral protective effects with hypothermic procedures including inhibition of neuron excitation, and discharge of excitable amino acids, and thereby, prevention of an increase in intercellular calcium ions, hyperoxidation of lipids in cell membranes, and free radical production.
The authors are briefly discussing the fundamental principles of using hypothermia as an adjunct tool of the cardiothoracic surgeon's practice. The relationship between temperature, flow, metabolic requirements and adverse effects is addressed.
To determine the nature of neurologic dysfunction after deep hypothermic circulatory arrest during aortic arch surgery, we reconsidered the cases of 154 patients who had undergone aortic arch surgery (either of the ascending or transverse aorta, or both) between November 1993 and July 1999. Temporary postoperative neurologic dysfunction was seen in 9 patients (5.8%), and another 3 patients (1.9%) experienced stroke. Patients with temporary neurologic dysfunction had no new infarct and were discharged home with no residual symptoms. Computed tomographic scans revealed that 2 patients with stroke had multiple infarcts in the brainstem, and the 3rd had bilateral border-zone infarcts. The patients with brainstem infarcts died on postoperative days 7 and 15, and the patient with border-zone infarct was discharged home with no symptoms 3 months after surgery.
Univariate analysis revealed that patients with neurologic deficits had significantly higher rates of history of hypertension, concomitant coronary artery bypass grafting, cardiac ischemia times longer than 90 minutes, and chronic renal failure. A multivariate logistic regression analysis revealed that the significant preoperative variables associated with neurologic deficits were a history of hypertension and a cardiac ischemia time longer than 90 minutes.
Deep hypothermic circulatory arrest is a safe and useful technique for protection of the brain during surgery for complex aortic problems. In future, some patients at extreme risk for perioperative neurologic complications might be offered novel neuroprotective agents, in combination with deep hypothermia.
Aneurysm, dissecting/surgery; body temperature; brain/metabolism; brain ischemia; brain injuries/diagnosis/prevention & control