Thoracic Aortic Aneurysm Surgery Research Articles

Open Distal Anastomosis Technique for Ascending Aortic Aneurysm Repair without Cerebral Perfusion

This study aimed to report the outcomes of patients who underwent proximal thoracic aortic aneurysm surgery with open distal anastomosis technique but without cerebral perfusion, instead under deep hypothermic circulatory arrest. Thirty patients (21 male, 9 female) who underwent ascending aortic aneurysm repair with open distal anastomosis technique were included. The average age was 60.2±11.7 years. Operations were performed under deep hypothermic circulatory arrest and the cannulation for cardiopulmonary bypass was first done over the aneurysmatic segment and then moved over the graft. Intraoperative and early postoperative mortality and morbidity outcomes were reported. Average duration of cardiopulmonary bypass and cross-clamps were 210.8±43 and 154.9±35.4 minutes, respectively. Average duration of total circulatory arrest was 25.2±2.4 minutes. There was one hospital death (3.3%) due to chronic obstructive pulmonary disease at postoperative day 22. No neurological dysfunction was observed during the postoperative period. These results demonstrate that open distal anastomosis under less than 30 minutes of deep hypothermic circulatory arrest without antegrade or retrograde cerebral perfusion and cannulation of the aneurysmatic segment is a safe and reliable procedure in patients undergoing proximal thoracic aortic aneurysm surgery.

Ascending Aortic Proaneurysmal Genetic Mutations with Antiatherogenic Effects

Thoracic aortic aneurysms are common and are associated with a high morbidity and mortality. Despite this lethal diagnosis, there is an increasing body of evidence to suggest that the diagnosis of an aneurysm, specifically in the ascending thoracic aorta, may significantly reduce the risk of developing systemic atherosclerosis. Clinical observations in the operating room have shown pristine blood vessels in patients undergoing surgery for thoracic aortic aneurysms. There is now evidence that both the carotid intima-media thickness and arterial calcification, which are early and late signs of atherosclerosis respectively, are decreased in those with thoracic aortic aneurysms. These clinical studies are supported by molecular, genetic, and pharmacological evidence. Two principle mechanisms have been identified to explain the relationship of a proaneurysmal state conferring protection from atherosclerosis. These include an excess proteolytic balance of matrix metalloproteinase activity, leading to fragmentation of elastic lamellae and disordered collagen deposition. In addition, transforming growth factor β modulates vascular smooth muscle cells, extracellular matrix, and leukocytes. This confers protection from the initial plaque formation and, later provides stability to the plaque possibly through alteration of the types I and II transforming growth factor β receptor ratio. Furthermore, studies are now beginning to establish an important role for statins and estradiol in modulating these complex pathways. In the future, as our understanding of these complex mechanisms underlying aneurysmal protection against atherosclerosis increases, corresponding therapies may be developed to offer protection from atherosclerosis.

Complications of spinal fluid drainage in thoracic and thoracoabdominal aortic aneurysm surgery in 724 patients treated from 1987 to 2013.

To study complications from spinal fluid drainage in open thoracic/thoracoabdominal and thoracic endovascular aortic aneurysm repairs to define risks of spinal fluid drainage. Retrospective, prospectively maintained, institutionally approved database. Single institution university center. 724 patients treated from 1987 to 2013 INTERVENTIONS: The authors drained spinal fluid to a pressure≤6 mmHg during thoracic aortic occlusion/reperfusion in open and ≤8 mmHg after stent deployment in endovascular procedures. Low pressure was maintained until leg strength was documented. If bloody fluid appeared, drainage was stopped. Head computed tomography (CT) and, if indicated, spine CT and magnetic resonance imaging (MRI) were performed for bloody spinal fluid or neurologic deficit. Spinal fluid drainage was studied for bloody fluid, CT/MRI-identified intracranial and spinal bleeding, neurologic deficit, and death. Seventy-three patients (10.1%) had bloody fluid; 38 (5.2%) had intracranial blood on CT. One patient had spinal epidural hematoma. Higher volume of fluid drained and higher central venous pressure during proximal clamping were associated with intracranial blood. Most patients with intracranial blood were asymptomatic. Six patients had neurologic deficits: of the 6, 3 died (0.4%), 1 (0.1%) had permanent hemiparesis, and 2 recovered. Three of the six deficits were delayed, associated with heparin anticoagulation. 10% of patients had bloody spinal fluid; half of these had intracranial bleeding, which was almost always asymptomatic. In these patients, immediately stopping drainage and correcting coagulopathy may decrease the risk of serious complications. Neurologic deficit from spinal fluid drainage is uncommon (0.8%), but has high morbidity and mortality.

Fibrinogen concentrate administration attributes to significant reductions of blood loss and transfusion requirements in thoracic aneurysm repair.

BackgroundRepair of thoracic aortic aneurysm (TAA) is often associated with massive hemorrhage aggravated by dilutional coagulopathy with severe hypofibrinogenemia. Although only fresh frozen plasma (FFP) is available for acquired hypofibrinogenemia in Japan, the hemostatic effect of FFP has not been enough for dilutional coagulopathy in TAA surgery. There are increasing reports suggesting that fibrinogen concentrate may be effective in controlling perioperative bleeding and reducing transfusion requirements.MethodsWe retrospectively analyzed the hemostatic effect of fibrinogen concentrate compared with FFP in total 49 cases of elective TAA surgery. In 25 patients, fibrinogen concentrate was administered when the fibrinogen level was below 150 mg/dL at the cardiopulmonary bypass (CPB) termination. The recovery of fibrinogen level, blood loss, and transfused units during surgery were compared between cases of this agent and FFP (n = 24).ResultsWe observed rapid increases in plasma fibrinogen level and subsequent improvement in hemostasis by administration of fibrinogen concentrate after CPB termination. The average volume of total blood loss decreased by 64% and the average number of transfused units was reduced by 58% in cases of fibrinogen concentrate given, in comparison with cases of only FFP transfused for fibrinogen supplementation.ConclusionsIn patients showing severe hypofibrinogenemia during TAA surgery, timely administration of fibrinogen concentrate just after removal from CPB is effective for hemostasis, and therefore in reducing blood loss and transfused volumes.

Thoracic Aortic Aneurysms in Octogenarians: The Results of Open Surgical Repair Using Hypothermic Circulatory Arrest with Antegrade Selective Cerebral Perfusion

Although recent progress has expanded the indications for thoracic aortic surgery to include elderly patients, the procedure remains extremely invasive. We performed a chart review to determine the early and late outcomes of thoracic aortic surgery using hypothermic circulatory arrest (HCA) and antegrade selective cerebral perfusion (ASCP) in octogenarians. Of 79 patients who underwent surgery for thoracic aortic aneurysms from April 2007 through December 2012, 8 patients 80 years or older were selected for analysis. Mean age at the time of surgery was 84.3±1.39 years. The diagnoses were aortic dissection in 5 patients and degenerative thoracic aneurysm in 3 patients. All patients underwent surgery with HCA. The lowest body temperature was 25℃ ASCP was used as an additional brain-protection technique. Emergency operations were performed in 5 patients (62.5%). The mean duration of HCA was 60.4±19.7 minutes, that of aortic cross-clamping time was 143.0±30.4 minutes, and mean pump time was 207.8±44.4 minutes. The hospital mortality rate was 0%. Major postoperative complications occurred in 3 (37.5%) patients: stroke, temporary neurologic dysfunction, and paraparesis in 1 patient each. No patients required temporary dialysis for new-onset renal dysfunction. There were no deaths during the 65-month follow-up period. The early and late outcomes after thoracic aortic surgery at our hospital using HCA with ASCP in octogenarians are acceptable. The operations are performed with an acceptable operative risk, even under emergency situations, including acute aortic dissection.

Thoracic and thoracoabdominal aortic repair under regional spinal cord hypothermia

Spinal cord deficits are devastating complications after surgery for thoracic and thoracoabdominal aortic aneurysms. We developed a regional spinal cord cooling system using an epidural catheter containing cold saline within an isolated counter-current lumen to prevent such complications and reviewed the clinical results. We enrolled 37 patients with thoracic (n = 13) and thoracoabdominal (n = 24) aortic aneurysms that were repaired using the regional spinal cord cooling system under mild hypothermia with a partial femoro-femoral bypass. Although 2 patients died before hospital discharge (hospital mortality, 5.4%), none developed neurological deficits such as paraplegia or paraparesis. The outcomes of surgery for thoracic and thoracoabdominal aortic aneurysms under regional spinal cord hypothermia using a custom-designed epidural catheter were excellent. Although our patient cohort was small, the results indicate that our technique might help to improve the outcomes of thoracic and thoracoabdominal aortic repair.

Efficacy of iloprost and montelukast combination on spinal cord ischemia/reperfusion injury in a rat model

BackgroundThe thoracic or thoracoabdominal aortic aneurysm surgery may cause spinal cord ischemia because of aortic cross-clamping and may result in severe postoperative complications caused by spinal cord injury. Ischemia/reperfusion injury may directly or indirectly be responsible for these complications. In this study we sought to determine whether combination of iloprost and montelukast can reduce the ischemia/reperfusion injury of spinal cord in a rat model.MethodsMedulla spinalis tissue concentrations of interleukin-6 (IL-6), myeloperoxidase (MPO) and heat shock protein 70 (HSP-70) were determined in 3 groups of Spraque Dawley rats: control group (operation with cross clamping and intraperitoneal administration of 0.9% saline, n = 7), sham group (operation without cross clamping, n = 7), and study group (operation with cross-clamping and intraperitoneal administration of iloprost (25 ng/kg) and montelukast (1 mg/kg), n = 7). The abdominal aorta was clamped for 45 minutes, with a proximal (just below the left renal artery) and a distal (just above the aortic bifurcation) clip in control and study groups. Hindlimb motor functions were evaluated at 6, 12, 24, and 48 hours using the Motor Deficit Index score. All rats were sacrificed 48 hours after the procedure and spinal cord tissue levels of myeloperoxidase, interleukin-6, and heat shock protein (HSP-70) were evaluated as markers of oxidative stress and inflammation. Histopathological analyses of spinal cord were also performed.ResultsThe tissue level of HSP-70 was found to be similar among the 3 groups, however, MPO was highest and IL-6 receptor level was lowest in the control group (p = 0.007 and p = 0.005; respectively). In histopathological examination, there was no significant difference among the groups with respect to the neuronal cell degeneration, edema, or inflammation, but vascular congestion was found to be significantly more prominent in the control group than in the sham or in the study group (p = 0.05). Motor deficit index scores at 24 and 48 hours after ischemia were significantly lower in the study group than in the control group.ConclusionThis study suggests that combined use of iloprost and montelukast may reduce ischemic damage in transient spinal cord ischemia and may provide better neurological outcome.

Complications of cerebrospinal fluid drainage after thoracic aortic surgery: A review of 504 patients over 5 years

Cerebrospinal fluid drainage, a well-established means of preventing paraplegia after thoracic aortic aneurysm surgery, can result in serious, sometimes lethal complications. In a large group of patients who underwent surgical thoracic aortic aneurysm repair with cerebrospinal fluid drainage, we examined the incidences of and potential risk factors for these outcomes. The records were reviewed of 504 patients who underwent surgical thoracic aortic aneurysm repair with cerebrospinal fluid drainage at the Texas Heart Institute at St. Luke's Episcopal Hospital between February 2005 and December 2009. All historical data, inpatient records, and billing data were searched for evidence of complications. Of the 504 patients, 14 (2.8%) had intracranial hemorrhage, of whom 10 (72%) had subdural hematoma. Postdural puncture headache developed in 49 patients (9.7%), of whom 17 (34.6%) required epidural blood patch placement for resolution. Multivariable analysis identified having a connective tissue disorder (odds ratio, 3.08; 95% confidence interval, 1.33-7.13) as an independent predictor of postdural puncture headache, but not age less than 40 years (odds ratio, 0.97; 95% confidence interval, 0.94-0.99). Cerebrospinal fluid drainage, as performed by our method, seems to be associated with a modest rate of intracranial bleeding in patients who undergo surgical thoracic aortic aneurysm repair. In contrast, postdural puncture headache is not uncommon, particularly in patients with connective tissue disease. Clinicians caring for these patients should consider the likelihood of postdural puncture headache, and any such patient with postoperative headache should be assessed for epidural blood patch placement.

Cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery

During aortic aneurysm surgery, cross-clamping can lead to inadequate blood supply to the spinal cord resulting in neurological deficit. Cerebrospinal fluid drainage (CSFD) may increase the perfusion pressure to the spinal cord and hence reduce the risk of ischaemic spinal cord injury. To determine the effect of CSFD during thoracic and thoracoabdominal aortic aneurysm (TAAA) surgery on the risk of developing spinal cord injury. For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 31 2012) and CENTRAL (2012, Issue 5) for publications describing randomised controlled trials of cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery. Reference lists of relevant articles were checked. Randomised trials involving CSFD during thoracic and TAAA surgery. Both authors assessed the quality of trials independently. SNK extracted data and GS verified the data. Three trials with a total of 287 participants operated on for Type I or II TAAA were included.In the first trial of 98 participants, neurological deficits in the lower extremities occurred in 14 (30%) of CSFD group and 17 (33%) controls. The deficit was observed within 24 hours of the operation in 21 (68%), and from three to 22 days in 10 (32%) participants. CSFD did not have a significant benefit in preventing ischaemic injury to the spinal cord.The second trial of 33 participants used a combination of CSFD and intrathecal papaverine. It showed a statistically significant reduction in the rate of postoperative neurological deficit (P = 0.039), compared to controls. Analysis was undertaken after only one third of the estimated sample size had entered the trial.In the third trial TAAA repair was performed on 145 participants. CSFD was initiated during the operation and continued for 48 hours after surgery. Paraplegia or paraparesis occurred in 9 of 74 participants (12.2%) in the control group versus 2 of 82 participants (2.7%) receiving CSFD (P = 0.03). Overall, CSFD resulted in an 80% reduction in the relative risk of postoperative deficits. Meta-analysis showed an odds ratio (OR) of 0.48 (95 % confidence interval (CI) 0.25 to 0.92). For CSFD-only trials, OR was 0.57 (95% CI 0.28 to 1.17) and for intention-to-treat analysis in CSFD-only studies, the OR remained unchanged. There are limited data supporting the role of CSFD in thoracic and thoracoabdominal aneurysm surgery for prevention of neurological injury. Further clinical and experimental studies are indicated.

Improvement of motor evoked potentials monitoring is required during thoracic or thoracoabdominal aortic aneurysm surgery under hypothermic cardiopulmonary bypass

Keywords Motor evoked potential Thoracoabdominalaortic aneurysm HypothermiaMonitoring of motor evoked potentials (MEPs) can provideinformation about the functional integrity of a motorpathway and, therefore, has been widely used during sur-gery in which a motor pathway is at risk of injury,including craniotomy, spine/spinal surgery, and thoracic orthoracoabdominal aortic aneurysm (TAA or TAAA) sur-gery [1, 2]. Because myogenic MEPs are very sensitive tosuppression by anesthetic agents and neuromuscularblockade, careful attention should be paid to anestheticmanagement during monitoring of MEPs. In general, totalintravenous anesthesia with propofol and opioids is used,although ketamine-based anesthesia may be applied incases in which recording of myogenic MEPs is not reliablebecause of suppression by anesthetic agents or influence bypreoperative motor dysfunction.Of the cases in which MEPs monitoring is required,TAA/TAAA surgery is the most challenging for reliableMEP monitoring. In addition to the effects of anesthetics,a variety of factors can affect the recording of MEPs,including hypothermia, aortic clamp, and induction ofcardiopulmonary bypass (CPB). Hypothermia may havedirect effects on the MEP itself and also indirect effects onMEPs by changing the pharmacokinetics and pharmaco-dynamics of anesthetic agents, modified by the effects ofaortic clamp and the induction of CPB. Leslie et al. [3]demonstrated that a temperature reduction of 3 C increasedblood propofol concentration by 30 C during a constantrate infusion. Kakinohana et al. [4] reported that plasmapropofol concentration increased and bispectral indexvalues decreased rapidly after aortic cross-clamping inthoracic aortic aneurysm repair surgery during propofolanesthesia. Yoshitani et al. [5] demonstrated that, in patientsreceiving propofol infusion at a rate of 5 or 6 mg/kg/h,plasma propofol concentration increased and burst sup-pression rate on electroencephalogram increased after theinduction of normothermic CPB, compared with thosevalues before CPB. These findings suggest that interpre-tation of MEP changes could be difficult because anestheticlevel can easily fluctuate during TAAA surgery withhypothermic CPB.Data regarding the effects of hypothermia on myogenicMEPs have been limited to animal experiments. Meylaertset al. [6] investigated the effects of regional spinal cordhypothermia on myogenic MEPs induced by transcranialtrain-pulse stimulation in pigs anesthetized with ketamine,sufentanil, clonidine, and nitrous oxide. They demonstratedthat progressive cooling resulted in an increase of MEPs at28 –30 C and was followed by a progressive decrease inMEP amplitude. MEP amplitude decreased below 25% atapproximately 14 C. Sakamoto et al. [7] also investigatedthe effects of systemic hypothermia on myogenic MEPsinduced by a single pulse and a train of pulses under

Rapid Ischemic Preconditioning with a Short Reperfusion Time Prevents Delayed Paraplegia in a Rabbit Model

Surgery for thoracic and thoracoabdominal aortic aneurysms can be complicated by a significant incidence of neurogenic deficits due to spinal cord ischemia. In this study, we investigated whether ischemic preconditioning (IPC) improves neurologic outcome in a rabbit model. Forty rabbits underwent infrarenal aortic occlusion. The IPC group (n = 20) had 10 minutes of aortic occlusion to induce spinal cord ischemia, 40 minutes of reperfusion, and 30 minutes of ischemia, whereas the control group (n = 20) had only 30 minutes of ischemia. Tarlov scoring (0, paraplegia; 4, normal) was used to evaluate neurologic functions 7 days later, and spinal cord segments (L4-L6) were stained with hematoxylin and eosin for histologic evaluation. Complete paraplegia (grade 0) occurred in 15 (75%) of the 20 control animals, whereas in the IPC group, 13 (65%) of 20 animals were completely normal (grade 4) (P < .05). IPC is beneficial for protecting against neurologic damage after transient aortic occlusion in a rabbit model; however, the protective mechanisms are not clear.

Percutaneous cardiopulmonary support in surgery for descending thoracic aortic aneurysms

There is uncertainty regarding the optimal method of intraoperative management of patients with aneurysm of the descending thoracic aorta. Although the percutaneous cardiopulmonary support (PCPS) was developed for use in patients with severe heart failure, it has been applied during the resection of descending thoracic aortic aneurysms in our department since 1993. The purpose of this study was to retrospectively compare conventional axillo-iliac temporary bypass to PCPS in patients undergoing repair of a thoracic aortic aneurysm. We retrospectively reviewed 18 consecutive patients with thoracic aortic aneurysms who underwent repair between January 1989 and March 1995. There were 10 patients who underwent aneurysm resection using axillo-iliac temporary bypass (Group I) and 8 who underwent resection using PCPS (Group II). The clamp time, bypass time, estimated blood loss and transfusion requirement did not differ significantly between the two groups. The operating and anesthesia times in Group II (390±91 minutes and 598.8±26.3 minutes, respectively) were significantly shorter than those in Group I (514±100 minutes and 821.5±32.5 minutes, respectively). The duration of postoperative intubation, intensive care unit (ICU) stay, and postoperative hospitalization were significantly shorter in Group II (1.6±0.9, 5.3±1.0, and 17.6±5.6 days, respectively) than in Group I (5.0±2.4, 2.8±0.3, and 24.3±4.8 days, respectively). Percutaneous cardiopulmonary support is a useful technique in surgery for thoracic aortic aneurysms. The advantages of this technique over conventional axillo-iliac temporary bypass are shortened operative time, duration of intubation, ICU stay, and postoperative hospitalization. In addition, it is easy to maintain the bypass flow using a centrifugal pump, and to maintain the body temperature using a heating exchanger.

Current strategies for spinal cord protection during thoracic and thoracoabdominal aortic aneurysm repair

Surgery for thoracoabdominal aortic aneurysms remains challenging, with high mortality and morbidity rates despite overall improvements in the outcome of aortic surgery. Paraplegia and paraparesis remain devastating complications that severely restrict the chance of survival as well as the postoperative quality of life. Preventive measures vary considerably because the causes of spinal cord insufficiency are multifactorial. Here, we review measures to prevent paraplegia/paraparesis arising after surgery for thoracic and thoracoabdominal aortic aneurysms.

Anesthesia Literature Review

Anesthesia Literature Review

Spinal Cord Protection with a Cerebrospinal Fluid Drain in a Patient Undergoing Thoracic Endovascular Aortic Repair

Paralysis and paraparesis are dreaded complications of thoracic endovascular aortic repair (TEVAR) that occur with an incidence of 2%-6%. Risks factors include the type of thoracic aortic pathology treated, coverage of the left subclavian artery origin without revascularization, concomitant infrarenal abdominal aortic aneurysm repair, extent of stent graft coverage of the thoracic aorta, and renal failure. Cerebral spinal fluid (CSF) drains have been advocated as one of several protective strategies to prevent spinal cord ischemia. This case discussion briefly addresses the evidence supporting the use of CSF drains in patients undergoing TEVAR and offers an algorithm for managing CSF drains.

Can Intraoperative Motor-Evoked Potentials Predict All the Spinal Cord Ischemia During Moderate Hypothermic Beating Heart Descending Thoracic or Thoraco-Abdominal Aortic Surgery?

Paraplegia is a serious complication of descending thoracic or thoraco-abdominal aortic aneurysm (DTAA or TAAA, respectively) surgery. The functional integrity of the spinal cord can be monitored with intraoperative motor-evoked potentials (MEPs). Herein, we evaluated the results and adequacy of MEP monitoring. Between March 2006 and April 2009, 33 patients (24 males and 9 females) were monitored with MEPs and reviewed retrospectively. The mean age was 50.7 ± 15.2 years. Eighteen and 15 patients underwent TAAA and DTAA repairs, respectively. We routinely used femoro-femoral partial bypass and cerebrospinal fluid (CSF) drainage. If the MEP demonstrated a significant change, prompt protective interventions were performed. During the procedure, 31 patients (93.9%) had a detectable MEP, of whom four had significant MEP changes and only one had an accompanying alteration in the somatosensory-evoked potential. In-hospital mortality occurred in two patients (6.0%) because of mesenteric ischemia and sepsis, respectively. Postoperative paraplegia developed in two patients (6.0%), one with an undetectable MEP and another with no significant intraoperative MEP change. Both patients had hypotensive events and impaired CSF drainage in the immediate postoperative period. Permanent paraplegia persisted in one patient. In four patients with intraoperative MEP changes, paraplegia did not occur. Although intraoperative monitoring of MEP has been shown to be effective in detecting cord ischemia during DTAA or TAAA surgery, it is not definitive and cannot predict all neurologic deficits. Other postoperative preventive strategies such as CSF drainage and maintaining a high blood pressure are important to prevent paraplegia.

Elective Thoracic Aortic Aneurysm Surgery: Better Outcomes from High-Volume Centers

Although studies have demonstrated clinical advantages in high-volume (HV) centers performing esophageal and pancreatic resections, thoracic aortic aneurysm repair has not been studied in the same fashion. We sought to determine if HV centers have better outcomes after thoracic aortic aneurysm surgery relative to lower-volume (LV) centers. Retrospective review of prospectively collected data pooled from the 17 institutions participating in the Virginia Cardiac Surgery Quality Initiative (VCSQI) database was performed during a 3-year period. LV centers were those that performed <40 operations during the study period, and HV centers were those that performed >80 operations. Preoperative risk factors and outcomes were compared between the 2 groups. Multivariate analysis was performed to evaluate the impact of center volume on mortality. Only elective operations were studied. HV centers performed 515 operations during the study period compared with 216 operations from LV centers. Perioperative mortality was significantly lower in HV centers (3.7%, n = 19) versus LV centers (8.3%, n = 18) (p = 0.02). Incidence of renal failure (HV: 4.5%; LV: 8.3%; p = 0.05) and prolonged ventilator course (HV: 16.7%; LV: 25.5%; p = 0.01) were also lower in the HV centers relative to LV centers. HV centers had higher stroke rates compared with LV centers (HV: 4.8%, LV: 1.4%; p < 0.01). Total hospital cost was $42,736 in HV centers and $51,296 in LV centers (p = 0.04). On regression analysis, LV centers were significantly associated with increased complications and mortality (all p < 0.05). Although LV centers had lower stroke rates, HV centers had overall better outcomes, lower mortality rates, and considerably lower cost compared with LV centers.

Regional Spinal Cord Cooling Using a Countercurrent Closed-Lumen Epidural Catheter

We developed a method of regional spinal cord cooling by using an epidural catheter containing cold saline in its isolated counter-current lumen. We describe the clinical application of this innovative procedure to the prevention of paraplegia during surgery for thoracic and thoracoabdominal aortic aneurysms.

Computer-Simulated Fluid Dynamics of Arterial Perfusion in Extracorporeal Circulation: From Reality to Virtual Simulation

Atheroembolism due to aortic manipulation remains an unsolved problem in surgery for thoracic aortic aneurysm. The goal of the present study is to create a computer simulation (CS) model with which to analyze blood flow in the diseased aorta. A three-dimensional glass model of the aortic arch was constructed from CT images of a normal, healthy person and a patient with transverse aortic arch aneurysm. Separately, a CS model of the curved end-hole cannula was created, and flow from the aortic cannula was recreated using a numerical simulation. Comparison of the data obtained by the glass model analyses revealed that the flow velocity and the vector of the flow around the exit of the cannula were similar to that in the CS model. A high-velocity area was observed around the cannula exit in both the glass model and the CS model. The maximum flow velocity was as large as 1.0 m/s at 20 mm from the cannula exit and remained as large as 0.5 to 0.6 m/s within 50 mm of the exit. In the aortic arch aneurysm models, the rapid jet flow from the cannula moved straight toward the lesser curvature of the transverse aortic arch. The locations and intensities of the calculated vortices were slightly different from those obtained for the glass model. The proposed CS method for the analysis of blood flow from the aortic cannulae during extracorporeal circulation can reproduce the flow velocity and flow pattern in the proximal and transverse aortic arches.

Predictors of Mortality after Endovascular Repair of the Thoracic Descending Aorta – The Preliminary New Zealand Experience

As the mortality rates associated with open surgery for thoracic aortic aneurysms and type B aortic dissection are within the range of 5-20% and 6-67%, endovascular technology has been developed as a minimally invasive alternative treatment. Such techniques avoid the need for thoracotomy, aortic cross-clamping, and left-sided heart bypass, and are associated with shorter operative times and hospital stays. The incidence of spinal cord ischaemia and paraplegia has been consistently low after endovascular repair of thoracic aneurysms. The latter includes patients in whom long aortic segments and the danger zone (T9-L1), that usually gives the origin to the anterior spinal artery, have been covered by the endograft.