Clinical Application of Intermittent Pressure-Augmented Retrograde Cerebral Perfusion
2010; Elsevier BV; Volume: 90; Issue: 4 Linguagem: Inglês
10.1016/j.athoracsur.2010.03.024
ISSN1552-6259
AutoresHiroshi Kubota, Shinichi Takamoto, Hideaki Yoshino, Kazuhiko Kitahori, Mitsuhiro Kawata, Kunihiko Tonari, Hidehito Endo, Hiroshi Tsuchiya, Yusuke Inaba, Yu Takahashi, Kenichi Sudo,
Tópico(s)Traumatic Brain Injury and Neurovascular Disturbances
ResumoBrain protection is important during aortic arch surgery, especially in patients with cerebral ischemia. We clinically applied the effectiveness of a novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection in a canine model, as described in a previous report. Although, in our patient the brachiocephalic artery and left subclavian artery were occluded as a result of aortitis, there was a history of right cerebral infarction, recovery of consciousness, and no neurologic sequelae. Near-infrared oximetry showed recovery of intracranial blood oxygen saturation every time the pressure was augmented. Brain protection is important during aortic arch surgery, especially in patients with cerebral ischemia. We clinically applied the effectiveness of a novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection in a canine model, as described in a previous report. Although, in our patient the brachiocephalic artery and left subclavian artery were occluded as a result of aortitis, there was a history of right cerebral infarction, recovery of consciousness, and no neurologic sequelae. Near-infrared oximetry showed recovery of intracranial blood oxygen saturation every time the pressure was augmented. Brain protection during aortic arch surgery is important, especially in patients with cerebral ischemia. To prolong the safe limits of conventional retrograde cerebral perfusion (RCP), Kitahori and colleagues [1Kitahori K. Takamoto S. Takayama H. et al.A novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection.J Thorac Cardiovasc Surg. 2005; 130: 363-370Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar], and Kawata and colleagues [2Kawata M. Takamoto S. Kitahori K. et al.Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.J Thorac Cardiovasc Surg. 2006; 132: 80-88Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar] assessed a novel protocol, intermittent pressure-augmented retrograde cerebral perfusion (IPA-RCP), in a canine model [1Kitahori K. Takamoto S. Takayama H. et al.A novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection.J Thorac Cardiovasc Surg. 2005; 130: 363-370Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 2Kawata M. Takamoto S. Kitahori K. et al.Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.J Thorac Cardiovasc Surg. 2006; 132: 80-88Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar]. We clinically applied this new protocol in a young woman with aortitis syndrome. Although her brachiocephalic artery and left subclavian artery were occluded, and although she also had a history of cerebral infarction, she recovered consciousness well after total arch replacement and aortic valve replacement, and she had no neurologic complications. Near infrared oximetry showed recovery of intracranial blood oxygen saturation during the pressure augmentation.A 25-year-old woman was referred to our department because of aortitis syndrome, an ascending aorta aneurysm, and severe aortic regurgitation. She had a history of infarction of the right corpus striatum at 23 years of age. She experienced sudden left hemiparesis, but she recovered well, with weakness of the left upper extremity as the only sequela.Steroid therapy had already been started, and the laboratory data showed no evidence of inflammation. The bilateral radial artery pulse was weak, and her blood pressure could not be determined. A computed tomographic scan showed an aneurysm extending from the ascending aorta to the aortic arch, having a maximum diameter of 76 mm. A magnetic resonance image showed occlusion of the brachiocephalic artery and the left subclavian artery (Fig 1A). An echocardiography revealed severe aortic regurgitation, but no annuloectasia. Left ventricular function was intact. An intracranial magnetic resonance image revealed mild atrophy of the right cerebral hemisphere, and a magnetic resonance angiographic image showed that the right brain was perfused by the left internal carotid artery through the circle of Willis (Figs 1B and 1C). Brain perfusion scintigraphy showed markedly reduced perfusion of the right cerebral hemisphere (Fig 1D). Total arch replacement and aortic valve replacement were planned. The patient selected aortic valve replacement with a bioprosthesis.The operation was performed on September 2007. The pericardium was opened through a median sternotomy, and dense inflammatory pericardial adhesions were carefully dissected. Cardiopulmonary bypass was established through bi-caval and ascending aorta cannulations. The left ventricle was vented through the right superior pulmonary vein. During cooling, the ascending aorta was clamped, and aortic valve replacement with a 21-mm bioprosthetic valve was performed using an intravalvular technique [3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar]. When the patient's tympanic temperature reached to 18°C, circulatory arrest and IPA-RCP were commenced. The aortic arch was opened, and the aorta was transected distal to the left subclavian artery. A four-branched 26-mm graft with a 5-cm elephant trunk was anastomosed. Only a small dimple was detected at the site of orifice of the left subclavian artery. After anastomosis of the left common carotid artery, the graft was clamped and IPA-RCP switched to antegrade perfusion through a side branch of the graft. During warming, anastomosis of the brachiocephalic artery was performed. Finally, proximal anastomosis at the sinotubular junction was performed, and the aorta was de-clamped. All anastmoses were reinforced with Teflon felt strips (Bard Inc, Murray Hill, NJ). Weaning from the cardiopulmonary bypass was achieved without difficulty. The duration of IPA-RCP was 75 minutes.Initially, the oxygenated blood was perfused through the superior vena cava at a pressure of 15 mm Hg to 20 mm Hg. Two minutes later, the initial pressure augmented perfusion at 45 mm Hg was attempted and was then lowered. The duration of the augmentation was 30 seconds, and the perfusion pressure was then lowered to 20 mm Hg. This 30 second augmentation followed by a 2-minute interval was repeated through the arch reconstruction.Intracranial regional oxygen saturation (rSO2) was measured with a TOS-96 brain oximeter (TOSTEC Co, Ltd, Tokyo, Japan).The patient recovered consciousness soon after the operation with no neurologic abnormalities, and her postoperative course was uneventful. Postoperative brain perfusion scintigraphy showed normal right brain perfusion.Initial right and left rSO2 was 75% and 80%, respectively, and it gradually decreased after commencing RCP. After the start of IPA-RCP, rSO2 increased, and between the augmentations, the rSO2 values decreased. At the end of RCP, the rSO2 values went down to 53% and 62%, respectively. Immediately after the resumption of antegrade perfusion through a side branch of the graft, the rSO2 values decreased to 51% and 57%, respectively, but then the rSO2 values smoothly recovered to their initial values (Fig 2A) . Postoperative brain perfusion scintigraphy showed improved perfusion of the right cerebra hemisphere (Fig 2B).Fig 2(A) Regional oxygen saturation (rSO2). Blue line shows right rSO2. Red line shows left rSO2. Arrow “a” indicates the start of intermittent pressure augmentation during retrograde cerebral circulation. Arrow “b” indicates the start of antegrade perfusion of the left common carotid artery. Initial right and left rSO2 was 75% and 80%, respectively. During deep-hypothermic circulatory arrest and RCP, the values were gradually decreased. The rSO2 values increased several percent each time IPA-RCP began, and they declined during the intervals between IPA-RCP. At the end of RCP, the rSO2 values decreased to 53% and 62%, respectively. The decline in the right rSO2 curve was larger than the left. (A) Just after the resumption of the antegrade perfusion from a side branch of the graft, rSO2 decreased to 51% and 57%, respectively, but then it recovered smoothly to the initial level. (B) Improved right brain perfusion was postoperatively confirmed.View Large Image Figure ViewerDownload (PPT)CommentRetrograde cerebral perfusion with augmentation of central venous pressure to 15 mm Hg to 20 mm Hg is commonly used for additional brain protection during deep-hypothermic circulatory arrest. However, the extent to which the deep-hypothermic circulatory arrest can be prolonged is limited, because at those pressures the intracranial vessels do not fully open. To overcome this drawback, Kitahori and colleagues [1Kitahori K. Takamoto S. Takayama H. et al.A novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection.J Thorac Cardiovasc Surg. 2005; 130: 363-370Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar], and Kawata and colleagues [2Kawata M. Takamoto S. Kitahori K. et al.Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.J Thorac Cardiovasc Surg. 2006; 132: 80-88Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar] developed a novel RCP method by elevating CVP up to 45 mm Hg, intermittently. Their experiment in a canine model showed that the retinal vessels in the IPA-RCP group were effectively dilated at an augmented pressure of 45 mm Hg (arteries, 107% ± 3% of control; veins, 114% ± 3% of control), whereas the antegrade selective cerebral perfusion group showed the retinal vessels were smaller than the corresponding preoperative vessels. They concluded that intermittent pressure augmentation allows an adequate blood supply and provides adequate neuroprotection equivalent to that provided by antegrade cerebral perfusion. It is also known that the continuous marked elevation in venous pressure causes brain edema; however, Kawata and colleagues [2Kawata M. Takamoto S. Kitahori K. et al.Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.J Thorac Cardiovasc Surg. 2006; 132: 80-88Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar] revealed that pathologic brain sections after IPA-RCA showed only minimal evidence of cellular change and no evidence of either cerebral edema or hemorrhage in animal experiment. They explain that even though the CSF pressure was significantly high when the RCP pressure was augmented, normal CSF pressure provided by intervals between pressure augmentations could prevent the cerebral edema in the IPA-RCP group [1Kitahori K. Takamoto S. Takayama H. et al.A novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection.J Thorac Cardiovasc Surg. 2005; 130: 363-370Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar].In the presented case, right and left rSO2 gradually decreased after the start of RCP, and the rSO2 curve was notched by the IPA-RCP. The essential effect of IPA-RCP may not only be a temporary increase in brain oxygen saturation, but elevation of the declining curve during RCP.Our preliminary randomized comparative study in clinical cases of IPA-RCP (n = 10) and standard RCP (n = 10) showed that the rSO2 decline ratio 60 minutes after the initiation of the IPA-RCP group was 13.1 ± 3.7% in contrast with 24.5 ± 13.1% in the RCP group (p < 0.05). It may support the “bottom raising effect” of this new protocol. In our patient, rSO2 decreased sharply just after the resumption of antegrade perfusion through a side branch of the graft, but then the rSO2 values recovered smoothly to the initial level. We call the sharp drop the “final dip.” The final dip always appears just after the resumption of antegrade perfusion after RCP and may represent washout of deoxygenated blood that was not perfused that remained in the brain. The presence of a final dip, despite the use of IPA-RCP, may mean that there is room for improvement in our protocol of IPA-RCP.Improved right brain perfusion was postoperatively confirmed. The treatment of the severe aortic regurgitation by aortic valve replacement and the elevation of diastolic blood pressure were believed to have contributed to the improvement. We were not only able to prevent aortic rupture and heart failure, but also cerebral ischemia due to hypoperfusion.Retrograde cerebral perfusion with intermittent pressure augmentation may contribute to brain protection and better clinical outcomes.In conclusion, IPA-RCP was applied to aortic arch surgery in a patient with severely impaired brain circulation secondary to aortitis syndrome. This novel protocol may have some advantages in comparison with conventional RCP. Because it is difficult to verify the efficacy of IPA-RCP by quantitative analysis, the accumulation and analysis of clinical data (eg, measurement of the concentration of Tau proteins in the CSF, comparison of the preoperative and postoperative cognitive function, measurement of the diameters of the retinal vessels during IPA-RCP, and measurement of oxygen extraction) may demonstrate the advantages of this new method of brain protection. Brain protection during aortic arch surgery is important, especially in patients with cerebral ischemia. To prolong the safe limits of conventional retrograde cerebral perfusion (RCP), Kitahori and colleagues [1Kitahori K. Takamoto S. Takayama H. et al.A novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection.J Thorac Cardiovasc Surg. 2005; 130: 363-370Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar], and Kawata and colleagues [2Kawata M. Takamoto S. Kitahori K. et al.Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.J Thorac Cardiovasc Surg. 2006; 132: 80-88Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar] assessed a novel protocol, intermittent pressure-augmented retrograde cerebral perfusion (IPA-RCP), in a canine model [1Kitahori K. Takamoto S. Takayama H. et al.A novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection.J Thorac Cardiovasc Surg. 2005; 130: 363-370Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 2Kawata M. Takamoto S. Kitahori K. et al.Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.J Thorac Cardiovasc Surg. 2006; 132: 80-88Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar]. We clinically applied this new protocol in a young woman with aortitis syndrome. Although her brachiocephalic artery and left subclavian artery were occluded, and although she also had a history of cerebral infarction, she recovered consciousness well after total arch replacement and aortic valve replacement, and she had no neurologic complications. Near infrared oximetry showed recovery of intracranial blood oxygen saturation during the pressure augmentation. A 25-year-old woman was referred to our department because of aortitis syndrome, an ascending aorta aneurysm, and severe aortic regurgitation. She had a history of infarction of the right corpus striatum at 23 years of age. She experienced sudden left hemiparesis, but she recovered well, with weakness of the left upper extremity as the only sequela. Steroid therapy had already been started, and the laboratory data showed no evidence of inflammation. The bilateral radial artery pulse was weak, and her blood pressure could not be determined. A computed tomographic scan showed an aneurysm extending from the ascending aorta to the aortic arch, having a maximum diameter of 76 mm. A magnetic resonance image showed occlusion of the brachiocephalic artery and the left subclavian artery (Fig 1A). An echocardiography revealed severe aortic regurgitation, but no annuloectasia. Left ventricular function was intact. An intracranial magnetic resonance image revealed mild atrophy of the right cerebral hemisphere, and a magnetic resonance angiographic image showed that the right brain was perfused by the left internal carotid artery through the circle of Willis (Figs 1B and 1C). Brain perfusion scintigraphy showed markedly reduced perfusion of the right cerebral hemisphere (Fig 1D). Total arch replacement and aortic valve replacement were planned. The patient selected aortic valve replacement with a bioprosthesis. The operation was performed on September 2007. The pericardium was opened through a median sternotomy, and dense inflammatory pericardial adhesions were carefully dissected. Cardiopulmonary bypass was established through bi-caval and ascending aorta cannulations. The left ventricle was vented through the right superior pulmonary vein. During cooling, the ascending aorta was clamped, and aortic valve replacement with a 21-mm bioprosthetic valve was performed using an intravalvular technique [3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar]. When the patient's tympanic temperature reached to 18°C, circulatory arrest and IPA-RCP were commenced. The aortic arch was opened, and the aorta was transected distal to the left subclavian artery. A four-branched 26-mm graft with a 5-cm elephant trunk was anastomosed. Only a small dimple was detected at the site of orifice of the left subclavian artery. After anastomosis of the left common carotid artery, the graft was clamped and IPA-RCP switched to antegrade perfusion through a side branch of the graft. During warming, anastomosis of the brachiocephalic artery was performed. Finally, proximal anastomosis at the sinotubular junction was performed, and the aorta was de-clamped. All anastmoses were reinforced with Teflon felt strips (Bard Inc, Murray Hill, NJ). Weaning from the cardiopulmonary bypass was achieved without difficulty. The duration of IPA-RCP was 75 minutes. Initially, the oxygenated blood was perfused through the superior vena cava at a pressure of 15 mm Hg to 20 mm Hg. Two minutes later, the initial pressure augmented perfusion at 45 mm Hg was attempted and was then lowered. The duration of the augmentation was 30 seconds, and the perfusion pressure was then lowered to 20 mm Hg. This 30 second augmentation followed by a 2-minute interval was repeated through the arch reconstruction. Intracranial regional oxygen saturation (rSO2) was measured with a TOS-96 brain oximeter (TOSTEC Co, Ltd, Tokyo, Japan). The patient recovered consciousness soon after the operation with no neurologic abnormalities, and her postoperative course was uneventful. Postoperative brain perfusion scintigraphy showed normal right brain perfusion. Initial right and left rSO2 was 75% and 80%, respectively, and it gradually decreased after commencing RCP. After the start of IPA-RCP, rSO2 increased, and between the augmentations, the rSO2 values decreased. At the end of RCP, the rSO2 values went down to 53% and 62%, respectively. Immediately after the resumption of antegrade perfusion through a side branch of the graft, the rSO2 values decreased to 51% and 57%, respectively, but then the rSO2 values smoothly recovered to their initial values (Fig 2A) . Postoperative brain perfusion scintigraphy showed improved perfusion of the right cerebra hemisphere (Fig 2B). CommentRetrograde cerebral perfusion with augmentation of central venous pressure to 15 mm Hg to 20 mm Hg is commonly used for additional brain protection during deep-hypothermic circulatory arrest. However, the extent to which the deep-hypothermic circulatory arrest can be prolonged is limited, because at those pressures the intracranial vessels do not fully open. To overcome this drawback, Kitahori and colleagues [1Kitahori K. Takamoto S. Takayama H. et al.A novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection.J Thorac Cardiovasc Surg. 2005; 130: 363-370Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar], and Kawata and colleagues [2Kawata M. Takamoto S. Kitahori K. et al.Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.J Thorac Cardiovasc Surg. 2006; 132: 80-88Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar] developed a novel RCP method by elevating CVP up to 45 mm Hg, intermittently. Their experiment in a canine model showed that the retinal vessels in the IPA-RCP group were effectively dilated at an augmented pressure of 45 mm Hg (arteries, 107% ± 3% of control; veins, 114% ± 3% of control), whereas the antegrade selective cerebral perfusion group showed the retinal vessels were smaller than the corresponding preoperative vessels. They concluded that intermittent pressure augmentation allows an adequate blood supply and provides adequate neuroprotection equivalent to that provided by antegrade cerebral perfusion. It is also known that the continuous marked elevation in venous pressure causes brain edema; however, Kawata and colleagues [2Kawata M. Takamoto S. Kitahori K. et al.Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.J Thorac Cardiovasc Surg. 2006; 132: 80-88Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar] revealed that pathologic brain sections after IPA-RCA showed only minimal evidence of cellular change and no evidence of either cerebral edema or hemorrhage in animal experiment. They explain that even though the CSF pressure was significantly high when the RCP pressure was augmented, normal CSF pressure provided by intervals between pressure augmentations could prevent the cerebral edema in the IPA-RCP group [1Kitahori K. Takamoto S. Takayama H. et al.A novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection.J Thorac Cardiovasc Surg. 2005; 130: 363-370Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar].In the presented case, right and left rSO2 gradually decreased after the start of RCP, and the rSO2 curve was notched by the IPA-RCP. The essential effect of IPA-RCP may not only be a temporary increase in brain oxygen saturation, but elevation of the declining curve during RCP.Our preliminary randomized comparative study in clinical cases of IPA-RCP (n = 10) and standard RCP (n = 10) showed that the rSO2 decline ratio 60 minutes after the initiation of the IPA-RCP group was 13.1 ± 3.7% in contrast with 24.5 ± 13.1% in the RCP group (p < 0.05). It may support the “bottom raising effect” of this new protocol. In our patient, rSO2 decreased sharply just after the resumption of antegrade perfusion through a side branch of the graft, but then the rSO2 values recovered smoothly to the initial level. We call the sharp drop the “final dip.” The final dip always appears just after the resumption of antegrade perfusion after RCP and may represent washout of deoxygenated blood that was not perfused that remained in the brain. The presence of a final dip, despite the use of IPA-RCP, may mean that there is room for improvement in our protocol of IPA-RCP.Improved right brain perfusion was postoperatively confirmed. The treatment of the severe aortic regurgitation by aortic valve replacement and the elevation of diastolic blood pressure were believed to have contributed to the improvement. We were not only able to prevent aortic rupture and heart failure, but also cerebral ischemia due to hypoperfusion.Retrograde cerebral perfusion with intermittent pressure augmentation may contribute to brain protection and better clinical outcomes.In conclusion, IPA-RCP was applied to aortic arch surgery in a patient with severely impaired brain circulation secondary to aortitis syndrome. This novel protocol may have some advantages in comparison with conventional RCP. Because it is difficult to verify the efficacy of IPA-RCP by quantitative analysis, the accumulation and analysis of clinical data (eg, measurement of the concentration of Tau proteins in the CSF, comparison of the preoperative and postoperative cognitive function, measurement of the diameters of the retinal vessels during IPA-RCP, and measurement of oxygen extraction) may demonstrate the advantages of this new method of brain protection. Retrograde cerebral perfusion with augmentation of central venous pressure to 15 mm Hg to 20 mm Hg is commonly used for additional brain protection during deep-hypothermic circulatory arrest. However, the extent to which the deep-hypothermic circulatory arrest can be prolonged is limited, because at those pressures the intracranial vessels do not fully open. To overcome this drawback, Kitahori and colleagues [1Kitahori K. Takamoto S. Takayama H. et al.A novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection.J Thorac Cardiovasc Surg. 2005; 130: 363-370Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar], and Kawata and colleagues [2Kawata M. Takamoto S. Kitahori K. et al.Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.J Thorac Cardiovasc Surg. 2006; 132: 80-88Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar] developed a novel RCP method by elevating CVP up to 45 mm Hg, intermittently. Their experiment in a canine model showed that the retinal vessels in the IPA-RCP group were effectively dilated at an augmented pressure of 45 mm Hg (arteries, 107% ± 3% of control; veins, 114% ± 3% of control), whereas the antegrade selective cerebral perfusion group showed the retinal vessels were smaller than the corresponding preoperative vessels. They concluded that intermittent pressure augmentation allows an adequate blood supply and provides adequate neuroprotection equivalent to that provided by antegrade cerebral perfusion. It is also known that the continuous marked elevation in venous pressure causes brain edema; however, Kawata and colleagues [2Kawata M. Takamoto S. Kitahori K. et al.Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.J Thorac Cardiovasc Surg. 2006; 132: 80-88Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Kawata M. Sekino M. Takamoto S. et al.Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.J Thorac Cardiovasc Surg. 2006; 132: 933-940Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar] revealed that pathologic brain sections after IPA-RCA showed only minimal evidence of cellular change and no evidence of either cerebral edema or hemorrhage in animal experiment. They explain that even though the CSF pressure was significantly high when the RCP pressure was augmented, normal CSF pressure provided by intervals between pressure augmentations could prevent the cerebral edema in the IPA-RCP group [1Kitahori K. Takamoto S. Takayama H. et al.A novel protocol of retrograde cerebral perfusion with intermittent pressure augmentation for brain protection.J Thorac Cardiovasc Surg. 2005; 130: 363-370Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar]. In the presented case, right and left rSO2 gradually decreased after the start of RCP, and the rSO2 curve was notched by the IPA-RCP. The essential effect of IPA-RCP may not only be a temporary increase in brain oxygen saturation, but elevation of the declining curve during RCP. Our preliminary randomized comparative study in clinical cases of IPA-RCP (n = 10) and standard RCP (n = 10) showed that the rSO2 decline ratio 60 minutes after the initiation of the IPA-RCP group was 13.1 ± 3.7% in contrast with 24.5 ± 13.1% in the RCP group (p < 0.05). It may support the “bottom raising effect” of this new protocol. In our patient, rSO2 decreased sharply just after the resumption of antegrade perfusion through a side branch of the graft, but then the rSO2 values recovered smoothly to the initial level. We call the sharp drop the “final dip.” The final dip always appears just after the resumption of antegrade perfusion after RCP and may represent washout of deoxygenated blood that was not perfused that remained in the brain. The presence of a final dip, despite the use of IPA-RCP, may mean that there is room for improvement in our protocol of IPA-RCP. Improved right brain perfusion was postoperatively confirmed. The treatment of the severe aortic regurgitation by aortic valve replacement and the elevation of diastolic blood pressure were believed to have contributed to the improvement. We were not only able to prevent aortic rupture and heart failure, but also cerebral ischemia due to hypoperfusion. Retrograde cerebral perfusion with intermittent pressure augmentation may contribute to brain protection and better clinical outcomes. In conclusion, IPA-RCP was applied to aortic arch surgery in a patient with severely impaired brain circulation secondary to aortitis syndrome. This novel protocol may have some advantages in comparison with conventional RCP. Because it is difficult to verify the efficacy of IPA-RCP by quantitative analysis, the accumulation and analysis of clinical data (eg, measurement of the concentration of Tau proteins in the CSF, comparison of the preoperative and postoperative cognitive function, measurement of the diameters of the retinal vessels during IPA-RCP, and measurement of oxygen extraction) may demonstrate the advantages of this new method of brain protection. We would like to gratefully acknowledge the outstanding original idea of the IPA-RCP protocol, laboratory investigation, and cooperation given to us by all the cardiac surgeons at the Tokyo University Hospital: Mituhiro Kawata, Kazuhiko Kitahori, Kan Nawata, Hiroo Takayama, Tetsuro Morota, Noboru Motomura, Minoru Ono, Syun-ei Kyo, and Shinichi Takamaoto.
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