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

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

Direct visualization of minimal cerebral capillary flow during retrograde cerebral perfusion: an intravital fluorescence microscopy study in pigs

BACKGROUND: Retrograde cerebral perfusion (RCP) is used in some centers during aortic arch surgery for brain protection during hypothermic circulatory arrest. It is still unclear however whether RCP provides adequate microcirculatory blood flow at a capillary level. We used intravital microscopy to directly visualize the cerebral capillary blood flow in a piglet model of RCP. METHODS: Twelve pigs (weight 9.7 +/- 0.9 kg) were divided into two groups (n = 6 each): deep hypothermic circulatory arrest (DHCA) and RCP. After the creation of a window over the parietal cerebral cortex, pigs underwent 10 minutes of normothermic bypass and 40 minutes of cooling to 15 degrees C on cardiopulmonary bypass ([CPB] pH-stat, hemocrit 30%, pump flow 100 mL x kg(-1) x min(-1)). This was followed by 45 minutes of DHCA and rewarming on CPB to 37 degrees C. In the RCP group the brain was retrogradely perfused (pump flow 30 mL x kg(-1) x min(-1)) during DHCA through the superior vena cava after inferior vena cava occlusion. Plasma was labeled with fluorescein-isothiocyanate-dextran for assessing microvascular diameter and functional capillary density (FCD), defined as total length of erythrocyte-perfused capillaries per observation area. Cerebral tissue oxygenation was determined by nicotinamide adenine dinucleotide hydrogen (NADH) autofluorescence, which increases during tissue ischemia. RESULTS: During normothermic and hypothermic antegrade cerebral perfusion the FCD did not significantly change from base line (97% +/- 14% and 96% +/- 12%, respectively). During retrograde cerebral perfusion the FCD decreased highly significantly to 2% +/- 2% of base line values (p < 0.001). Thus there was no evidence of significant capillary blood flow during retrograde cerebral perfusion. The microvascular diameter of cerebral arterioles that were slowly perfused significantly decreased to 27% +/- 6% of base line levels during RCP. NADH fluorescence progressively and significantly increased during RCP, indicating poorer tissue oxygenation. At the end of retrograde cerebral perfusion there was macroscopic evidence of significant brain edema. CONCLUSIONS: RCP does not provide adequate cerebral capillary blood flow and does not prevent cerebral ischemia. Prolonged RCP induces brain edema. However, there might be a role for a short period of RCP to remove air and debris from the cerebral circulation after DHCA because retrograde flow could be detected in cerebral arterioles.     

Retrograde Cerebral Perfusion with Hypothermic Blood Provides Efficient Protection of the Brain: A Neuropathological Study

Retrograde cerebral perfusion is a method that is recently being used for protection of the brain during operations on the aortic arch. This method is useful but is said to provide a limited time for protecting the brain. We designed an experiment in dogs to investigate neuropathologically the effect of protecting the brain for 120 minutes under: (1) circulatory arrest (CA); (2) retrograde cerebral perfusion with moderately cooled blood (RCPMC); and (3) retrograde cerebral perfusion with deeply cooled blood (RCPDC). We calculated the number of the abnormal cells of 400 hippocampal neurons per dog light microscopically. The number was 199 ± 23 (mean ± 1 SD) in the CA group, 149 ± 50 in the RCPMC group, and 72 ± 33 in the RCPDC group. The difference between the CA group and the RCPMC group was not statistically significant (p < 0.05), but there was a significant difference between the RCPMC and RCPDC groups (p < 0.05). The degree of cerebral protection provided by retrograde cerebral perfusion for 120 minutes is not sufficient when using moderately cooled blood. If we use deeply cooled blood at a temperature of about 10°C, we should obtain a sufficient degree of protection of the brain.     

Effects of magnesium sulfate on traumatic brain edema in ats

OBJECTIVE: To investigate the effects of magnesium sulfate on traumatic brain edema and explore its possible mechanism. METHODS: Forty-eight Sprague-Dawley (SD) rats were randomly divided into three groups: Control, Trauma and Treatment groups. In Treatment group, magnesium sulfate was intraperitoneally administered immediately after the induction of brain trauma. At 24 h after trauma, total tissue water content and Na(+), K(+), Ca(2+), Mg(2+) contents were measured. Permeability of blood-brain barrier (BBB) was assessed quantitatively by Evans Blue (EB) dye technique. The pathological changes were also studied. RESULTS: Water, Na(+), Ca(2+) and EB contents in Treatment group were significantly lower than those in Trauma group (P<0.05). Results of light microscopy and electron microscopy confirmed that magnesium sulfate can attenuate traumatic brain injury and relieve BBB injury. CONCLUSIONS: Treatment with MgSO4 in the early stage can attenuate traumatic brain edema and prevent BBB injury.     

Neuroprotective effects of nimodipine and MK-801 on acute infectious brain edema induced by injection of pertussis bacilli to neocortex of rats

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Effects of magnesium sulfate on traumatic brain edema in rats

svarietyofneuroprotectiveagentshavebeensynthesized .However ,besidessomeagentspresentlybeingevaluatedinclinicaltrails ,mostofthesecompoundshavelimitedclinicalusebecauseofneurotoxicityandbehavioralsideeffects .Recently ,severalstudiesdemonstratedthattraumaticinjurytothebraincausesadecreaseinmagnesiumconcentrationcorrelatedwithinjuryseverity .1Sincethen ,moreandmoreattentionhasbeen paidtoMgSO4 foritsneuroprotectiveeffects .Magnesiumsulfatehasbeenwidelyusedinclinicalpracticeforalmost 10 0 years.…     

Comparative study of brain protection in ascending aorta replacement for acute type A aortic dissection: retrograde cerebral perfusion versus selective antegrade cerebral perfusion

Objectives

Postoperative disorders of the central nervous system remain a major problem in thoracic aortic surgery. Both retrograde cerebral perfusion and selective antegrade cerebral perfusion have become established techniques for cerebral circulatory management. In this study, we compared neurologic outcomes and mortality between retrograde cerebral perfusion and antegrade selective cerebral perfusion in patients with acute type A aortic dissection who underwent emergency ascending aorta replacement.

Methods

Between January 2003 and April 2011, a total of 203 patients with acute type A aortic dissection underwent emergency ascending aorta replacement in our hospital. We performed retrograde cerebral perfusion in 109 patients before 2006, and then mainly performed antegrade selective cerebral perfusion in 94 patients from 2006 onward.

Results

Cardiopulmonary bypass time and systemic circulatory arrest time were significantly longer in the antegrade selective cerebral perfusion group (p?=?0.04, p?<?0.001, respectively). The incidences of transient brain dysfunction and permanent brain dysfunction after surgery did not differ significantly between the groups. There were also no differences between the groups in other intraoperative variables, such as aortic cross-clamp time and the lowest rectal temperature, or in operative outcomes, including postoperative intensive-care-unit stay, mean peak amylase, and lipase levels until postoperative day 7, and 30-day mortality.

Conclusion

Both retrograde cerebral perfusion and antegrade selective cerebral perfusion were associated with acceptable levels of postoperative neurologic deficits, mortality, and morbidity. Either of these techniques for brain protection can be used selectively, based on a comprehensive assessment of general condition, in patients undergoing surgery for acute type A aortic dissection.     

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

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

大鼠自体原位肝移植中逆行灌注法对急性肺损伤的影响

目的探讨大鼠自体原位肝移植术中经下腔静脉逆行灌注与经门静脉顺行灌注法对急性肺损伤的影响。方法 Sprague-Dawley(SD)大鼠75只随机分成逆行灌注组、顺行灌注组、假手术组,建立大鼠自体原位肝移植逆行灌注、顺行灌注和假手术模型,各组于术后6h、12h、24h分别随机处死6只大鼠,测定肺干/湿重量比值、肺组织髓过氧化物酶(myeloperoxidase,MPO)活性、丙二醛(malondialdehyde,MDA)含量、肿瘤坏死因子(TNF)-α含量,行肺组织病理学检查。结果与假手术组比较,逆行灌注组和顺行灌注组术后肺干/湿重量比值变小,肺组织MPO活性、MDA含量、TNF-α含量增加,以术后6h与12h明显。与顺行灌注组比较,逆行灌注组术后6h、12h的肺干/湿重量比值较高,而肺组织MPO活性、MDA含量较低,差异有统计学意义(均为P<0.05);术后24h两组间在上述指标差异无统计学意义(均为P>0.05);逆行灌注组肺组织TNF-α含量在术后6h、12h、24h均显著降低,两组间差异有统计学意义(均为P<0.05)。肺组织苏木素-伊红染色:逆行灌注组、顺行灌注组均表现不同程度的肺泡结构破坏,肺泡间隔增厚,小静脉、毛细血管充血、淤血,炎症细胞浸润。其中术后6h、12h表现较重,术后24h较轻;同时显示逆行灌注组肺组织病理损伤较顺行灌注组明显减轻。结论大鼠自体原位肝移植术中用顺行灌注或逆行灌注,术后早期均存在急性肺损伤,其中术后6h和12h损伤较严重,术后24h肺损伤减轻;逆行灌注造成的急性肺损伤程度比顺行灌注要轻。     

Advantages of Continuous Noncardioplegic Warm Blood Retrograde Perfusion Over Antegrade Perfusion During Proximal Coronary Anastomoses

Retrograde perfusion via the coronary sinus supplies vascular beds distal to coronary stenoses and has been used for administration of cardioplegia. An additional application is to supply noncardioplegic retrograde perfusion while performing proximal anastomoses (a time when cardiac arrest is not critical). The aim of this study was to determine the safety of this technique and to study the metabolic changes with antegrade versus retrograde warm blood perfusion. Sixty-six patients, with good left ventricular function, underwent distal coronary bypass in a similar fashion. Proximal anastomoses were done with 1) partial occlusion clamp (n = 29) or 2) cross-clamp on and continuous, warm, noncardioplegic retrograde blood perfusion (n = 37). In an additional 10 patients, metabolism was assessed with antegrade and retrograde perfusion during proximal anastomoses. Despite longer cross-clamp times (96.4 ± 6.2 vs 80.8 ± 3.1 min, p < 0.05) with retrograde perfusion, the total duration of cardiopulmonary bypass was significantly less (119.6 ± 6.2 vs 136.6 ± 4.6 min, p < 0.05). There was superior postbypass, intraoperative hemodynamics (cardiac index) with retrograde perfusion (4.0 ± 0.2 vs 3.6 ± 0.1 L/min/m²). The incidence of postoperative dysrhythmia was not significantly different between groups. Oxygen and glucose utilization was more efficient with retrograde perfusion. Retrograde perfusion during proximal anastomoses is a safe technique. There is diminished risk of aortic dissection, atheroembolism, delayed aneurysm formation, or rupture due to avoidance of application of partial occlusion clamps. There is evidence of superior substrate utilization.     

Use of a pH-stat strategy during retrograde cerebral perfusion improves cerebral perfusion and tissue oxygenation

BACKGROUND: Although it is well documented that the use of a pH-stat strategy during hypothermic cardiopulmonary bypass improves cerebral blood flow, an alpha-stat strategy has been almost exclusively used during retrograde cerebral perfusion. We investigated the effects of pH-stat and alpha-stat management on brain tissue blood flow and oxygenation during retrograde cerebral perfusion in a porcine model to determine if the use of a pH-stat strategy during retrograde cerebral perfusion improves brain tissue perfusion. METHODS: Fourteen pigs were managed by an alpha-stat strategy (alpha-stat group, n = 7) or by a pH-stat strategy (pH-stat group, n = 7) during 120 minutes of hypothermic retrograde cerebral perfusion. Retrograde cerebral perfusion was established through the superior vena cava. Brain tissue blood flow and oxygenation were measured continuously with a laser flowmeter and near infrared spectroscopy, respectively. Brain tissue water content was determined at the end of the experiments. RESULTS: During cooling, brain tissue blood flow was significantly higher with use of the pH-stat strategy than with the alpha-stat strategy (86% +/- 10% versus 40% +/- 3% of baseline). During retrograde cerebral perfusion, brain tissue blood flow was also significantly higher (about three times higher) in the pH-stat group than in the alpha-stat group (15% +/- 4% versus 5% +/- 1% of baseline at 60 minutes of retrograde cerebral perfusion). Tissue oxygen saturation appeared to be higher during retrograde cerebral perfusion in the pH-stat group than in the alpha-stat group. Brain tissue blood flow during rewarming remained significantly higher with the use of pH-stat than with the use of alpha-stat. Brain tissue water contents were similar in both groups. CONCLUSIONS: In our pig model, the use of a pH-stat strategy during retrograde cerebral perfusion significantly improves brain tissue perfusion. Therefore, to improve retrograde cerebral blood flow during retrograde cerebral perfusion, it may be preferable to use a pH-stat strategy, rather than an alpha-stat strategy.     

Methylprednisolone does not decrease eicosanoid concentrations or edema in brain tissue or improve neurologic outcome after head trauma in rats.

Methylprednisolone was recently reported to significantly improve motor and sensory function after acute spinal cord injury in patients. Our study was designed to determine whether methylprednisolone exerts a beneficial effect after head injury. Diethyl ether-anesthetized rats were assigned to receive surgery with no cranial impact and no methylprednisolone (group A, n = 13); surgery with no cranial impact and intraperitoneal methylprednisolone (greater than or equal to 60 mg/kg) (group B, n = 8); surgery with cranial impact and no methylprednisolone (group C, n = 8, and group E, n = 8); or surgery with cranial impact and methylprednisolone (greater than or equal to 60 mg/kg) (group D, n = 15, and group F, n = 13). Neurologic severity score was determined at 1, 2, 4, and 24 h (when appropriate) after injury, and brain tissue eicosanoid levels and cerebral edema were determined when the animals were killed (4 h after injury in groups C and D and 24 h after injury in groups E and F). Treatment with methylprednisolone did not improve neurologic severity score or edema formation and did not alter brain tissue levels of prostaglandin E2, thromboxane B2, or 6-keto-prostaglandin F1 alpha at any time period. The authors conclude that methylprednisolone does not exert a beneficial effect on brain tissue edema or functional activity after cranial impact in rats.     

Retrograde Cerebral Perfusion Results in Better Perfusion to the Striatum Than the Cerebral Cortex During Deep Hypothermic Circulatory Arrest: A Microdialysis Study

It remains controversial whether contemporary cerebral perfusion techniques, utilized during deep hypothermic circulatory arrest (DHCA), establish adequate perfusion to deep structures in the brain. This study aimed to investigate whether selective antegrade cerebral perfusion (SACP) or retrograde cerebral perfusion (RCP) can provide perfusion equally to various anatomical positions in the brain using metabolic evidence obtained from microdialysis. Eighteen piglets were randomly assigned to 40 min of circulatory arrest (CA) at 18°C without cerebral perfusion (DHCA group, n = 6) or with SACP (SACP group, n = 6) or RCP (RCP group, n = 6). Microdialysis parameters (glucose, lactate, pyruvate, and glutamate) were measured every 30 min in cortex and striatum. After 3 h of reperfusion, brain tissue was harvested for Western blot measurement of α‐spectrin. After 40 min of CA, the DHCA group showed marked elevations of lactate and glycerol and a reduction in glucose in the microdialysis perfusate (all P < 0.05). The changes in glucose, lactate, and glycerol in the perfusate and α‐spectrin expression in brain tissue were similar between cortex and striatum in the SACP group (all P > 0.05). In the RCP group, the cortex exhibited lower glucose, higher lactate, and higher glycerol in the perfusate and higher α‐spectrin expression in brain tissue compared with the striatum (all P < 0.05). Glutamate showed no difference between cortex and striatum in all groups (all P > 0.05). In summary, SACP provided uniform and continuous cerebral perfusion to most anatomical sites in the brain, whereas RCP resulted in less sufficient perfusion to the cortex but better perfusion to the striatum.     

Toxicity of photodynamic therapy with photofrin in the normal rat brain

The widespread acceptance of photodynamic therapy (PDT), a potential adjuvant brain tumor therapy under clinical evaluation since 1980, has been partially restrained by its potential toxicity toward normal brain tissue. This study examined PDT-produced injury of normal rat brain as a function of photosensitizer dose. Brain injury was characterized by correlating measurements of the area of cerebral edema using T2-weighted magnetic resonance images, measurement of brain water content at the lesion site, microscopic examination of histological sections through the PDT lesion, and by evaluation of the area of blood brain barrier (BBB) disruption using computerized morphometric analysis of the region of Evans blue (EB) dye-labelled albumin extravasation. Monochromatic red light (630 nm) was delivered intracere-brally using a 5-mm-long cylindrical, diffusion-tip optical fiber at a constant energy dose of 15 joules. A Photofrin dose of 2 mg/kg of body weight produced a transient breakdown in the blood brain barrier around the site of the implanted optical fiber demonstrated by magnetic resonance imaging (MRI), extravasation of EB dye and pallor on hematoxylin and eosin-stained microscopic tissue sections. A much larger area of BBB disruption was seen at a dose of 4 mg/kg of Photofrin, and this drug dose resulted in significant permanent brain injury. In this model, a Photofrin dose of 4 mg/kg body weight is not tolerated by the normal brain. © 1994 Wiley-Liss, Inc.     

Protective Effect of Continuous Retrograde Cerebral Perfusion on the Brain During Deep Hypothermic Systemic Circulatory Arrest

Deep hypothermic circulatory arrest has been widely used as an adjunct for surgery of the aortic arch to protect the brain and other vital organs. We introduced the use of continuous retrograde cerebral perfusion via the superior vena cava during deep hypothermic circulatory arrest in 1987 and have used it in 33 patients. Continuous retrograde cerebral perfusion times ranged from 10 to 89 minutes (mean 40.2 ± 22.5), and minimal nasopharyngeal temperatures ranged from 14 to 25°C (mean 17.4 ± 2.0). Two patients with a ruptured aneurysm died during operation due to bleeding and two other patients, with continuous retrograde cerebral perfusion time of 24 and 35 minutes, died 1 month postoperatively due to preoperative liver cirrhosis and sepsis. Two patients suffered from stroke. The remaining 27 patients, including 6 with from 60 to 82 minutes of continuous retrograde cerebral perfusion, had no complications related to continuous retrograde perfusion. During continuous retrograde cerebral perfusion, 66 pairs of blood samples from the perfusate and from the drainage back to the arch vessels were obtained. Analysis of these samples revealed that partial pressure of oxygen, saturation of oxygen, and oxygen content significantly decreased (p < 0.001), and partial pressure of carbon dioxide (CO₂) and CO₂ content significantly increased (p < 0.001). The nasopharyngeal temperature gradually increased at the rate of 0.01 to 0.03°C/min, but was maintained below 20°C. These results reflect the fact that the aerobic metabolism of the brain is maintained during continuous retrograde cerebral perfusion due to oxygen and substrate availability. This technique offers the potential of metabolic support to the brain during deep hypothermic circulatory arrest and prolongs the safe time limits of deep hypothermic circulatory arrest in surgery of the aortic arch. (J Card Surg 1994;9:584–595)     

Cerebral autoregulation after hypothermic circulatory arrest in operations on the aortic arch

BACKGROUND: The purpose of this study was to determine whether patients who undergo thoracic aorta repairs with the aid of hypothermic circulatory arrest experience impairments in cerebral autoregulation, and to ascertain the influence of three different techniques of cerebral protection on autoregulatory function. METHODS: Sixty-seven patients undergoing elective aortic arch procedures with hypothermic circulatory arrest were tested for cerebral dynamic autoregulation using continuous transcranial Doppler velocity and blood pressure recordings. Twenty-three patients were treated using hypothermic circulatory arrest without adjuncts (group 1), 25 using antegrade cerebral perfusion (group 2), and 19 using retrograde cerebral perfusion (group 3). RESULTS: There were no hospital deaths. Two major strokes occurred in this series; 9 patients experienced temporary neurologic dysfunction: in all these patients severe impairment of cerebral autoregulation was observed. Cerebral autoregulation in the immediate postoperative period was preserved only in patients treated with antegrade cerebral perfusion. Severe impairments were observed in the other two groups in which the degree of autoregulatory response was inversely correlated to the duration of the cerebral protection time during hypothermic circulatory arrest. Postoperative improvement of autoregulatory function was observed in the majority of patients. Our data suggest the exposure to brain damage in the presence of autoregulation impairment, thus indicating that postoperative hypotensive phases may further contribute to neurologic impairment. CONCLUSIONS: The status of cerebral autoregulation in the postoperative period after hypothermic circulatory arrest procedures is profoundly altered. The degree of impairment is influenced by the cerebral protection technique. This study indicates the beneficial role of antegrade perfusion during hypothermic circulatory arrest for the preservation of this function and suggests that postoperative cerebral autoregulation impairment can be regarded as an expression of central nervous system injury.     

单侧与双侧顺行性脑灌注的前瞻性随机对照研究

目的 比较全主动脉弓替换术中单侧顺行性脑灌注（ASCP）和双侧ASCP的脑保护效果。方法 16例全主动脉弓替换术病人随机分为单侧ASCP组和双侧ASCP组，每组各8例。两组均行术前、术后颅脑计算机体层摄影（CT）、术中均动态监测无名动脉及左颈总动脉压力，均行颈内静脉球血样血气分析。结果 两组各有1例出现短暂性神经功能异常。在ASCP期间单侧组无名动脉压高于左颈总动脉压（P〈0．01），而双侧组无名动脉压与左颈总动脉压相同。两组间各时间段颈静脉血氧分压、颈静脉血氧饱和度差异无统计学意义（P〉0．05）。结论 在基底动脉环完整，存在有效侧支循环条件下，单侧ASCP及双侧ASCP均能取得良好效果。单侧灌注操作较为简便，双侧灌注在ASCP期间两侧灌注压较为均衡，双侧灌注是否增加脑栓塞的危险尚需进一步研究。     

Effects of Antegrade and Retrograde Machine Perfusion Preservation on Cardiac Function After Transplantation in Canines

Introduction

Most studies investigating machine perfusion preservation for heart transplantation perfuse through the aortic root (antegrade), but the coronary sinus (retrograde) is a potential option. We hypothesized that retrograde machine perfusion provides better functional protection than static storage, while avoiding the potential irregular perfusion seen when aortic insufficiency occurs with antegrade perfusion.

Materials and Methods

Eighteen canine donor hearts were arrested, procured, and stored in modified Celsior solution for 4 hours by using either static storage at 0°C to 4°C (n = 6) or machine perfusion preservation at 5°C via the aortic root (antegrade, n = 6) or coronary sinus (retrograde, n = 6). Lactate and myocardial oxygen consumption were measured in perfused hearts. Hearts were reimplanted and reperfused for 6 hours with hourly function calculated by using the preload recruitable stroke work (PRSW) relation. Myocardial water content was determined at the end of the experiment.

Results

Storage lactate levels and myocardial oxygen consumption were comparable in both perfused groups. The PRSW was increased immediately after bypass in the antegrade group (120.6 ± 19.1 mm Hg) compared with the retrograde (75.0 ± 11.3 mm Hg) and static (78.1 ± 10.5 mm Hg) storage groups (P < .05). At the end of reperfusion, PRSW was higher in the retrograde group (69.8 ± 7.4 mm Hg) compared with the antegrade (40.1 ± 6.8 mm Hg) and static (39.9 ± 10.9 mm Hg) storage groups (P < .05). Myocardial water content was similar among groups.

Conclusions

Both antegrade and retrograde perfusion demonstrated excellent functional preservation, at least equivalent to static storage. Initial function was superior in the antegrade group, but the retrograde hearts displayed better function late after reperfusion. Neither perfused group developed significant edema. Machine perfusion preservation is a promising technique for improving results of cardiac transplantation.     

Comparison of metabolic responses to deep hypothermic total circulatory arrest and retrograde cerebral perfusion in an experimental model

An experimental study was designed to search the effectiveness of retrograde cerebral perfusion which is presently used as cerebral protection method for the surgery of arcus aorta. Twelve dogs were subjected to the study. Six of them were remained in total circulatory arrest at 20 degrees C for 60 min. Retrograde cerebral perfusion was done again at 20 degrees C for 1 h for the other six dogs.Tumor necrosis factor (TNF), P-selectin, Intracellular Adhesion Molecule (ICAM), Creatine Phosphokinase (CPK-BB) and tissue Adenosine triphosphate (ATP) levels were measured, before the cardiopulmonary bypass at 37 degrees C and during perfusion period at 5, 60 min and 4 h.Tissue ATP level for retrograde cerebral perfusion group was 3.99+/-0.7 mcmol/g tissue and 2.86+/-0.1 mcmol/g tissue for total circulatory arrest group at fourth hour (p<0.05). TNF level was significantly higher in total circulatory arrest group than retrograde cerebral perfusion group (p<0.05). The samples taken at fourth hour of reperfusion showed the TNF level was, 162.55+/-13.1 pcg/ml for total circulatory arrest group and this value was 12.5+/-3.4 pcg/ml for retrograde cerebral perfusion group.ICAM (Intracellular Adhesion Molecule) level was higher in total circulatory arrest group (18.75+/-3.6 ng/ml) when compared to retrograde cerebral perfusion group (8.75+/-1.8 ng/ml) (p<0.05).All parameters showed that retrograde cerebral perfusion preserved the brain functions better comparing with total circulatory arrest. The time necessary for aortic surgery may be provided by the retrograde cerebral perfusion technique.     

Cerebral perfusion

Aortic arch surgery necessitates interrupted brain perfusion and carries a risk of brain injury. Various brain protective techniques have been advocated to reduce risk including hypothermic arrest and retrograde or selective antegrade perfusion. Knowledge of the pathophysiologic consequences of deep hypothermia, may aid the surgeon in deciding when to initiate circulatory arrest and for how long. Retrograde cerebral perfusion use was advocated to prolong safe arrest durations but may not improve outcomes. Selective antegrade cerebral perfusion appears to have become the preferred method of brain protection. However, the delivery conditions and optimal perfusate constitution require further study.