Spinal Cord Perfusion and Protection During Descending Thoracic and Thoracoabdominal Aortic Surgery: The Collateral Network Concept

Single-stage thoracic and abdominal endovascular aneurysm repair for multilevel aortic disease

This investigation evaluated the results of single-stage thoracic endovascular aneurysm repair (TEVAR) and endovascular aneurysm repair (EVAR) for multilevel aortic disease in a series of nine patients. The lesions repaired included thoracic and abdominal aortic aneurysms (n= 7) and subacute type B dissections with abdominal aortic aneurysms (n=2). All procedures were successfully performed, and none of the patients experienced postoperative stroke or spinal cord ischemia. The median follow-up period for these patients was 18.9 months (range 1.7-31.4 months) and none of the patients exhibited any signs of type I endoleaks or aneurysmal diameter enlargements more than 5 mm. In conclusion, single-stage TEVAR and EVAR procedures for multilevel aortic disease were found to be safe and feasible modalities for high-risk patients.

Rat model of spinal cord injury preserving dura mater integrity and allowing measurements of cerebrospinal fluid pressure and spinal cord blood flow

PURPOSES

Cerebrospinal fluid (CSF) pressure elevation may worsen spinal cord ischaemia after spinal cord injury (SCI). We developed a rat model to investigate relationships between CSF pressure and spinal cord blood flow (SCBF).

METHODS

Male Wistar rats had SCI induced at Th10 (n = 7) or a sham operation (n = 10). SCBF was measured using laser-Doppler and CSF pressure via a sacral catheter. Dural integrity was assessed using subdural methylene-blue injection (n = 5) and myelography (n = 5).

RESULTS

The SCI group had significantly lower SCBF (p < 0.0001) and higher CSF pressure (p < 0.0001) values compared to the sham-operated group. Sixty minutes after SCI or sham operation, CSF pressure was 8.6 ± 0.4 mmHg in the SCI group versus 5.5 ± 0.5 mmHg in the sham-operated group. No dural tears were found after SCI.

CONCLUSION

Our rat model allows SCBF and CSF pressure measurements after induced SCI. After SCI, CSF pressure significantly increases.

The concept of aortic replacement based on computational fluid dynamic analysis: patient-directed aortic replacement

OBJECTIVES

Aortic replacement is based on the aortic diameter in the absence of dissection or connective tissue diseases. Frequently, a number of different aortic-to-prosthetic anastomotic positions are possible depending on patient factors and surgeon preferences. High stress on residual aortic tissue may result in aneurysm formation or aneurysmal dilatation. Utilizing a computational fluid dynamic evaluation, we aimed to define possible optimal operative interventions with regard to the extent of aortic replacement.

METHODS

For proof of principle, a computational fluid dynamic (CFD) analysis, using Fluent 6.2 (Ansys UK Ltd, Sheffield, UK), was performed on a simplified ascending arch and descending aortic geometry. Wall shear stress in three dimensions was assessed for the standard operations: ascending aortic replacement, arch replacement and proximal descending aortic replacement.

RESULTS

Hermiarch replacement is superior to isolated ascending aortic replacement with regard to residual stress analysis on tissues (up to a 10-fold reduction). Aortic arch replacement with island implantation of the supra-aortic vessels may potentially result in high stress on the residual aorta (10-fold increase). Aortic arch replacement with individual supra-aortic vessel implantation may result in areas of high stress (10-fold increase) on native vessels if an inadequate length of supra-aortic tissue is not resected, regardless of it being aneurysmal.

CONCLUSIONS

Computational fluid dynamic evaluation, which will have to be patient-specific, 3D anatomical and physiological, potentially has enormous implications for operative strategy in aortic replacement surgery. CFD analysis may direct the replacement of normal-diameter aortas in the future.

Successful lung lobectomy for a lung cancer following thoracic endovascular aortic repair for a thoracic aortic aneurysm: report of a case

Lung cancer and a thoracic aortic aneurysm were detected simultaneously in a 79-year-old male patient with diabetes. The aneurysm was first treated by thoracic endovascular aortic repair. A right lower lobectomy was subsequently performed after the blood flow of the bronchial and intercostal arteries was confirmed by computed tomographic angiography. The bronchial stump was covered with an intercostal muscle flap. The patient's postoperative course was uneventful. Thoracic endovascular aortic repair is a useful and less invasive treatment for such cases, but a blood flow evaluation of the aortic branches should be done following this procedure before a lung resection is considered.

A new classification system for branch artery perfusion patterns in acute aortic dissection for examining the effects of central aortic repair

OBJECTIVES

We developed a new classification system for branch perfusion patterns in acute aortic dissection and used it to retrospectively evaluate the perfusion status of whole aortic branches and to examine the effects of central aortic repair.

METHODS

Thirty-four consecutive patients with acute type A aortic dissection underwent emergent surgery at our institution between August 2008 and December 2011. A retrospective review of pre- and postoperative computed tomographic angiography was performed. Branch perfusion patterns were categorized into three classes: Class I, dissection involving but not extending into the branch; Class II, dissection extending into the branch and Class III, dissection causing ostial avulsion.

RESULTS

In cervical branches (total 169 branches), 70 branches (41%) presented with Class I patterns, 58 (34%) with Class II and none with Class III. In abdominal branches (total 135 branches), 76 branches (56%) presented with Class I patterns, 12 (9%) with Class II and 18 (13%) with Class III. In common iliac arteries (total 68 arteries), 14 arteries (21%) presented with Class I patterns, 24 (35%) with Class II and none with Class III. After repair, among 21 high-risk cervical branches, 14 branches (67%) showed improvement, 3 (14%) preserved distal perfusion supplied through the patent branch false lumen and 4 (19%) showed no improvement in high-risk perfusion pattern or worsened. Among 22 high-risk abdominal branches, 18 branches (82%) showed improvement, 3 (14%) preserved distal perfusion supplied through the patent branch or aortic false lumen and 1 (5%) showed no improvement in high-risk perfusion pattern.

CONCLUSIONS

To overcome malperfusion syndromes associated with acute aortic dissection, recognition of diverse branch perfusion patterns through a universal classification system is imperative.

Non-pharmacological experimental treatments for spinal cord injury: a review

INTRODUCTION

Spinal cord injury is a complex result of primary mechanical damage and the secondary vascular compromise and inflammatory reactions. Depending on timing, different treatment modalities may have various effects.

CONCLUSIONS

We review the latest advances in terms of non-pharmacological experimental treatments.

Role of induced hypothermia in thoracoabdominal aortic aneurysm surgery

For more than 50 years, hypothermia has been used in aortic surgery as a tool for neuroprotection. Hypothermia has been introduced into thoracoabdominal aortic aneurysm (TAAA) surgery by many cardiovascular centers to protect the body's organs, including the spinal cord. Numerous publications have shown that hypothermia can prevent immediate and delayed motor dysfunction after aortic cross-clamping. Here, we reviewed the historical application of hypothermia in aortic surgery, role of hypothermia in preclinical studies, cellular and molecular mechanisms by which hypothermia confers neuroprotection, and the role of systemic and regional hypothermia in clinical protocols to reduce and/or eliminate the devastating consequences of ischemic spinal cord injury after TAAA repair.

Endovascular repair of thoracic aortic aneurysms

Degenerative aneurysms of the thoracic aorta are increasing in prevalence; open repair of descending thoracic aortic aneurysms is associated with high rates of morbidity and mortality. Repair of isolated descending thoracic aortic aneurysms using stent grafts was introduced in 1995, and in an anatomically suitable subgroup of patients with thoracic aortic aneurysm, repair with endovascular stent graft provides favorable outcomes, with decreased perioperative morbidity and mortality relative to open repair. The cornerstones of successful thoracic endovascular aneurysm repair are appropriate patient selection, thorough preprocedural planning, and cautious procedural execution, the elements of which are discussed here.

Total arch replacement with long elephant trunk anastomosed at the base of the innominate artery: a single-centre longitudinal experience

OBJECTIVE

Total arch replacement, with a long elephant trunk (ET) anastomosed at the base of the innominate artery using an undersized graft, is performed for a variety of arch aneurysms. We investigated the long-term clinical outcomes of this procedure, as well as its long-term effectiveness for preventing retrograde flow into the aneurysm and further dilation of the descending aorta.

METHODS

We treated 127 consecutive patients with an arch aneurysm, who were divided into two groups according to the diameter of the descending aorta at the Th6-Th8 thoracic vertebral level: 35 mm or less (Single-ET, n = 94) and >35 mm (Staged-ET, n = 33). The graft diameter was undersized by 10-20% of the distal aortic diameter. ET length was determined by preoperative computed tomography (CT) to locate the distal end at Th6-Th8. Thrombosis around the ET and the descending aorta diameter around the distal end of the ET were evaluated using CT.

RESULTS

Two patients (1.6%) died within 30 days, while seven (5.5%) died in the hospital, three (2.4%) had a new stroke, three (2.4%) had permanent paraplegia and one (0.8%) had paraparesis. CT demonstrated complete thrombosis of the perigraft space around the ET in 81 patients (86%) in the Single-ET group and 11 (33%) in the Staged-ET group within 1 month after surgery, but not in the remaining 35 patients. Twenty-seven of the 35 patients without complete thrombosis underwent a subsequent second-stage operation. In those, the descending aorta showed no further dilation around the distal end of the ET, while new-onset perigraft perfusion occurred in two patients in the Single-ET group at 14 and 126 months, respectively. Overall survival was 89, 86, 78 and 74% at 1, 3, 5 and 7 years, respectively.

CONCLUSIONS

Our operative strategy for extensive thoracic aortic aneurysms using a long ET technique yielded satisfactory short- and long-term outcomes.

The effect of distal aortic pressure on spinal cord perfusion in rats

BACKGROUND

Aortic cross clamping is associated with spinal cord ischemia. This study used a rat spinal cord ischemia model to investigate the effect of distal aortic pressure on spinal cord perfusion.

MATERIALS AND METHODS

Male Sprague-Dawley rats (n=12) were divided into three groups. In group A (n=4), the aorta was not occluded. In groups B (n=4) and C (n=4), the aorta was occluded. In group B the distal aortic pressures dropped to around 20 mmHg. In group C, the distal aortic pressure was decreased to near zero. The carotid artery and tail artery were cannulated to monitor the proximal aortic pressure and the distal aortic pressure. Fluorescent microspheres were used to measure the regional blood flow in the spinal cord.

RESULTS

After aortic occlusion, blood flow to the cervical spinal cord showed no significant difference among the three groups. In groups B and C, the thoracic and lumbar spinal cord and renal blood flow decreased. No microspheres were detected in the thoracic and lumbar spinal cord of group C.

CONCLUSION

The spinal cord blood flow is dependent on the distal aortic pressure after thoracic aortic occlusion.

Effect of pretreatment with simvastatin on spinal cord ischemia-reperfusion injury in rats

OBJECTIVE

The aim of this study was to evaluate the pretreatment effect of simvastatin on spinal cord ischemia-reperfusion injury.

DESIGN

Prospective, interventional study.

SETTING

University research laboratory.

PARTICIPANTS

Forty-five male Sprague-Dawley rats.

INTERVENTIONS

Rats were treated with oral simvastatin, 10 mg/kg (simvastatin group; n = 15) or saline (control group; n = 15) for 5 days before ischemia. Spinal cord ischemia was induced using a balloon-tipped catheter placed in the proximal descending aorta in the control and simvastatin groups, but not in the sham group (n = 15).

MEASUREMENTS AND MAIN RESULTS

Neurologic function was assessed daily using the motor deficit index until 7 days after reperfusion. After the last neurologic evaluation, a histologic examination of the spinal cord was performed. At day 1 after reperfusion, the simvastatin group showed a significantly lower motor deficit index compared with the control group (2.0, 2.0-2.0, v 4.0, 3.5-5.0; p < 0.001). This trend was sustained at day 7 (2.0, 1.5-2.0, v 4.0, 3.0-4.0; p < 0.001). The simvastatin group displayed a significantly larger number of normal motor neurons compared with the control group (mean ± SD, 31.7 ± 6.1 v 20.4 ± 4.4; p < 0.001). However, compared with the sham group, the simvastatin group displayed fewer intact motor neurons (sham group, 38.5 ± 5.1; p = 0.005).

CONCLUSIONS

Pretreatment with simvastatin, 10 mg/kg, given orally for 5 days before the ischemia-reperfusion insult, improved the neurologic outcome and preserved more normal motor neurons compared with the control group in a rat model of spinal cord ischemia-reperfusion.

Distal aortic perfusion during thoracoabdominal aneurysm repair for prevention of paraplegia

BACKGROUND

During thoracoabdominal aortic aneurysm (TAAA) surgery, decreased spinal cord perfusion can result in neurological deficits such as paraplegia and paraparesis. Distal aortic perfusion, alone or in combination with other adjuncts, may counter the decrease in spinal cord perfusion and hence reduce the risk of spinal cord injury.

OBJECTIVES

To determine the effectiveness of distal aortic perfusion with or without other adjuncts against other adjuncts without use of distal perfusion during TAAA surgery in reducing the risk of developing paraplegia and paraparesis.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Specialised Register (last searched 5 January 2012) and CENTRAL (Issue 4, 2011) were searched for publications describing randomised controlled trials of distal aortic perfusion during thoracoabdominal aortic aneurysm surgery. Reference lists of relevant studies were checked.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical trials of distal aortic perfusion during TAAA repair.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for inclusion by at least two authors, with excluded trials arbitrated by the third author.

MAIN RESULTS

There were no randomised controlled trials identified.

AUTHORS' CONCLUSIONS

Currently, there are no randomised controlled trials to support the role of distal aortic perfusion in TAAA surgery for prevention of neurological injury. However, randomised controlled trials are not always feasible based on ethical grounds. Observational studies suggest that distal aortic perfusion alone or in combination with other adjuncts, that is cerebrospinal fluid (CSF) drainage, reduces the rate of neurologic deficit across all types of TAAA; in particular making a striking difference in the rate of neurologic deficit following type II TAAA repair. In the absence of randomised controlled trials, we recommend a standardised approach to reporting through registry studies to strengthen the evidence base for distal aortic perfusion.

State of the art in neuroprotection during acute type A aortic dissection repair

Temporary (TND) or permanent neurologic dysfunctions (PND) represent the main neurological complications following acute aortic dissection repair. The aim of our experimental and clinical research was the improvement and update of the most common neuroprotective strategies which are in present use.

Hypothermic circulatory arrest (HCA): Cerebral metabolic suppression at the clinically most used temperatures (18-22°C) is less complete than had been assumed previously. If used as a ‘stand-alone’ neuroprotective strategy, cooling to 15-20°C with a jugular SO2 ≥ 95% is needed to provide sufficient metabolic suppression. Regardless of the depth of cooling, the HCA interval should not exceed 25 min. After 40 min of HCA, the incidence of TND and PND increases, after 60 min, the mortality rate increases.

Antegrade selective cerebral perfusion (ASCP): At moderate hypothermia (25-28°C), ASCP should be performed at a pump flow rate of 10ml/kg/min, targeting a cerebral perfusion pressure of 50-60mmHg. Experimental data revealed that these conditions offer an optimal regional blood flow in the cortex (80±27ml/min/100g), the cerebellum (77±32ml/min/100g), the pons (89±5ml/min/100g) and the hippocampus (55±16ml/min/100g) for 25 minutes. If prolonged, does ASCP at 32°C provide the same neuroprotective effect?

Cannulation strategy: Direct axillary artery cannulation ensures the advantage of performing both systemic cooling and ASCP through the same cannula, preventing additional manipulation with the attendant embolic risk. An additional cannulation of the left carotid artery ensures a bi-hemispheric perfusion, with a neurologic outcome of only 6% TND and 1% PND.

Neuromonitoring: Near-infrared spectroscopy and evoked potentials may prove the effectiveness of the neuroprotective strategy used, especially if the trend goes to less radical cooling.

Conclusion: A short interval of HCA (5 min) followed by a more extended period of ASCP (25 min) at moderate hypothermia (28°C), with a pump flow rate of 10ml/kg/min and a cerebral perfusion pressure of 50 mmHg, represents safe conditions for open arch surgery.

Impact of intercostal artery occlusion on spinal cord ischemia following thoracic endovascular aortic repair

OBJECTIVE

To evaluate intercostal artery patency following thoracic endovascular aortic repair (TEVAR) and its relationship with spinal cord ischemia (SCI).

METHODS

Patients with SCI (n = 7) and a matched control cohort (n = 18) were identified from a prospectively maintained database. Radiographic analysis of intercostal patency was assessed using 3-dimensional (3-D)-reconstructed images of pre- and postoperative CT angiograms (1-6 months, 6-12 months, and 1-5 years).

RESULTS

Patients with SCI had a higher incidence of perioperative hypotension (P < .01) and longer procedure duration (P = .01). While the mean number of patent intercostal arteries at each time interval was not significantly different between groups, both SCI (P = .002) and control (P <.001) groups demonstrated a significant reduction in patent intercostal arteries in the stented area of the aorta following TEVAR.

CONCLUSION

TEVAR decreases intercostal artery patency in the area of aortic coverage. Our data suggest that intercostal artery patency, in conjunction with perioperative hypotension, is an important contributor to postoperative SCI.

The collateral network concept: a reassessment of the anatomy of spinal cord perfusion

OBJECTIVE

Prevention of paraplegia after repair of thoracoabdominal aortic aneurysm requires understanding the anatomy and physiology of the spinal cord blood supply. Recent laboratory studies and clinical observations suggest that a robust collateral network must exist to explain preservation of spinal cord perfusion when segmental vessels are interrupted. An anatomic study was undertaken.

METHODS

Twelve juvenile Yorkshire pigs underwent aortic cannulation and infusion of a low-viscosity acrylic resin at physiologic pressures. After curing of the resin and digestion of all organic tissue, the anatomy of the blood supply to the spinal cord was studied grossly and with light and electron microscopy.

RESULTS

All vascular structures at least 8 μm in diameter were preserved. Thoracic and lumbar segmental arteries give rise not only to the anterior spinal artery but to an extensive paraspinous network feeding the erector spinae, iliopsoas, and associated muscles. The anterior spinal artery, mean diameter 134 ± 20 μm, is connected at multiple points to repetitive circular epidural arteries with mean diameters of 150 ± 26 μm. The capacity of the paraspinous muscular network is 25-fold the capacity of the circular epidural arterial network and anterior spinal artery combined. Extensive arterial collateralization is apparent between the intraspinal and paraspinous networks, and within each network. Only 75% of all segmental arteries provide direct anterior spinal artery-supplying branches.

CONCLUSIONS

The anterior spinal artery is only one component of an extensive paraspinous and intraspinal collateral vascular network. This network provides an anatomic explanation of the physiological resiliency of spinal cord perfusion when segmental arteries are sacrificed during thoracoabdominal aortic aneurysm repair.

Surgical repair of thoracoabdominal aortic aneurysms using the critical artery reattachment technique

In the study, we sought to retrospectively analyze the effectiveness and safety of surgical repair of thoracoabdominal aortic aneurysm using the critical artery reattachment technique. Twenty-three consecutive thoracoabdominal aortic aneurysm patients were treated using the technique of sequential aortic clamping and critical artery reattachment. The entire procedure was technically successful in all patients. One died of renal failure and the overall hospital mortality was 4.35%. The total incidence of complications was 21.74%. At a median follow-up of 33 months, all patients were alive. We found that the application of critical artery reattachment technique in the management of thoracoabdominal aortic aneurysm provides excellent short- and mid-term results in most patients. It could markedly increase the curing rate and reduce the morbidity of postoperative complications including paraplegia, ischemia of abdominal viscera, and renal failure.

Critical care of traumatic spinal cord injury

Approximately 11 000 people suffer traumatic spinal cord injury (TSCI) in the United States, each year. TSCI incidences vary from 13.1 to 52.2 per million people and the mortality rates ranged from 3.1 to 17.5 per million people. This review examines the critical care of TSCI. The discussion will focus on primary and secondary mechanisms of injury, spine stabilization and immobilization, surgery, intensive care management, airway and respiratory management, cardiovascular complication management, venous thromboembolism, nutrition and glucose control, infection management, pressure ulcers and early rehabilitation, pharmacologic cord protection, and evolving treatment options including the use of pluripotent stem cells and hypothermia.

Staged hybrid repair using telescoped stent graft fixation for aortic arch and descending aortic aneurysms

Staged repair of extensive thoracic aortic aneurysms is complicated, with a high incidence of interval rupture between stages. We describe the systematic staged hybrid procedure of a previous endovascular repair of a descending aortic aneurysm and open surgical repair of an aortic arch aneurysm. In the second-stage arch repair, the stent graft was easily retracted and fixed, without dissection, around the aortic arch aneurysm distal side. Extensive thoracic aortic aneurysms were managed without interim rupture or neurologic deficits. This approach avoided the potential for interim rupture because recovery from the first-stage endovascular repair was shorter than that from open repair.

[Spinal cord protection during open and endovascular surgery in thoracic and thoracoabdominal aorta diseases]

In recent decades great advances have been made in surgical procedures for treating thoracic and thoracoabdominal aorta defects. Associated mortality and morbidity rates have dropped considerably, mainly in major reference centers, but nonetheless continue to be significant. The need for new strategies to reduce mortality and morbidity has made endovascular approaches an attractive alternative for high-risk surgical patients. The most feared complications of these procedures include paraparesis and paraplegia, which have devastating consequences on patients' quality of life. We provide an updated review of the pathophysiology of spinal cord ischemia in open and endovascular surgery, as well as perioperative measures designed to protect the spinal cord in both types of procedure.

Minimizing cerebral embolism in resection of distal aortic arch aneurysm through a left thoracotomy

BACKGROUND

In order to reduce the risk of cerebral embolism during aortic replacement through a left thoracotomy, we performed ascending or arch aortic cannulation (AAC) as well as early extracorporeal perfusion (EEP) under deep hypothermic circulatory arrest (DHCA). In this study we examined the effectiveness of these modifications in preventing cerebral embolism after distal arch replacement.

METHODS

Between January 2006 and March 2010, 40 patients underwent distal arch replacement through a left thoracotomy, using 2 pieces of an artificial graft. In all patients, AAC, EEP, and the open technique for aortic anastomosis were performed under DHCA. The AAC resulted in the proximal aortic perfusion from the proximal site of the diseased aorta. The EEP was induced by aortic distal perfusion from the side branch of a distal graft. After completion of the proximal anastomosis under EEP and DHCA, anastomosis between the proximal and distal grafts was made during rewarming. Neurologic deficit in the brain and spinal cord, as well as early surgical results, were clinically evaluated.

RESULTS

There was no permanent neurologic deficit after the surgery in the operative survivors. No patient had a stroke (0%). Temporary paraplegia and paraparesis occurred in 1 and 2 patients, respectively (7.7%); all 3 patients were able to walk prior to their discharge from hospital. Mortality in this series was 5.0% (2 of 40 patients); the cause of death was rupture of an esophageal ulcer and cardiogenic shock possibly due to myocardial infarction.

CONCLUSIONS

The AAC and EEP, in addition to deep hypothermia and DHCA, minimized the risk of cerebral embolism after distal arch aortic replacement by the left lateral approach.

Thoraco-abdominal aorta revascularization through a retroperitoneal approach

OBJECTIVE

To investigate the application of the retroperitoneal approach in aortic surgery.

METHODS

We collected and analyzed data of 7 patients in Macau who presented with aortic diseases from 2007 to 2008 and were treated with aorta repair through retroperitoneal approach. Demographic features as well as intraoperative and postoperative data were analyzed. One case of thoracoabdominal aneurysm and 4 cases of abdominal aneurysm received artificial graft, among which hybrid iliac artery reconstruction with Zenith stent covering the ostium of the left subclavian artery was performed in 2 cases of infrarenal abdominal aneurysm. Aortic-iliac artery bypass was performed in 2 cases of aortoiliac occlusion.

RESULTS

No operative or early postoperative death was observed. No perioperative intestinal adhesion or ureteral obstruction was found. One case reported delayed paraplegia and graft infection as postoperative complications. The complications were partially removed 3 months later after rehabilitation.

CONCLUSION

Retroperitoneal approach is a safe and feasible technique, which associated with a low incidence of postoperative pulmonary complications.

Delayed postoperative paraplegia and graft infection after a thoracoabdominal dissection

WE REPORT THE SUCCESSFUL TREATMENT OF THORACOABDOMINAL DISSECTION, WHICH EXTENDED INTO THE LEFT ILIAC ARTERY, DESPITE TWO INDEPENDENT COMPLICATIONS: graft infection and a relatively rare, delayed postoperative paraplegia. The paraplegia suddenly occurred on postoperative day 10, and after an intravenous infusion of heparin and methylprednisolone, it gradually subsided. Moreover, graft infection was diagnosed on postoperative day 27, and with continuous irrigation of antibiotic treatment it was cured without recurrence of infection. Although anticoagulation therapy is not indicated for paraplegia, we suppose that it might be used as an adjunct therapeutic.

Effect of chronic dissection on early and late outcomes after descending thoracic and thoracoabdominal aneurysm repair

OBJECTIVE

Although chronic aortic dissection (CD) has traditionally been considered a predictor of perioperative morbidity and mortality after descending thoracic/thoracoabdominal aneurysm repair (thoracoabdominal aortic aneurysm [TAA]), recent reports have rejected this assertion. Still, few contemporary studies document late outcomes after TAA for CD, which is the goal of this study.

METHODS

From August 1987 to December 2005, 480 patients underwent TAA; 73 (15%) CD and 407 (85%) degenerative aneurysms (DA). Operative management consisted of a clamp-and-sew technique with adjuncts in 53 (78%) CD and 355 (93%) DA patients (P < .001). Epidural cooling was used to prevent spinal cord injury (SCI) in 51 (70%) CD and 214 (53%) DA patients (P = .007). Study end points included perioperative SCI/mortality, freedom from reintervention, and long-term survival.

RESULTS

CD patients were younger (mean age 64.5 years CD vs 72.5 years DA, P < .001) and more frequently had a family history of aneurysmal disease (23% CD vs 6% DA, P < .001). Forty-three (59%) CD patients had elective TAA (vs 322 (79%) DA, P = .001). Eleven (15%) CD patients had Marfan's syndrome (vs 0% DA, P < .001), and 17 (23%) CD patients had a prior arch or ascending aortic repair (vs 16 [4%] DA, P < .001). CD patients were more likely to have Crawford type I & II thoracoabdominal aneurysms (44 [60%] vs 120 [29%] DA, P < .001), while only two (3%) CD patients had type IV aneurysms (vs 99 [24%] DA). There was no difference in perioperative mortality between the two groups (11% CD vs 8.6% DA, P = .52), nor was there a difference in flaccid paralysis, which occurred in five (7%) CD and 22 (5%) DA patients (P = .92). At 5 years, 70% of CD patients were free from reintervention versus 74% of DA (P = .36). The actuarial survival was 53% and 32% at 5 and 10 years for CD versus 47% and 17% for DA (P = .07).

CONCLUSIONS

Despite increased operative complexity, CD does not appear to increase perioperative SCI or mortality after TAA when compared with DA. Long-term freedom from aneurysm-related reintervention is similar for both groups as is survival, despite patients with CD being of younger age at presentation.

What is the best method for brain protection in surgery of the aortic arch? Selective antegrade cerebral perfusion

Despite considerable progress in the operative management of lesions involving the transverse aortic arch, replacement of this portion of the vessel remains a surgical challenge and is still associated with mortality and morbidity. This situation is due not only to the technical difficulties of the procedure but, often, to the unsatisfactory preservation of the integrity of the central nervous system during the period of arch exclusion. The techniques of cerebral protection during surgery of the aortic arch can be divided into those aimed at suppressing the metabolic demand of the central nervous system and those aimed at maintaining the metabolic supply during the time of exclusion of the cerebral vessels. Whichever technique is used, it must maintain the normal metabolism of the central nervous system or, at least, allow restoration of the physiologic conditions of its function. In this regard, selective antegrade cerebral perfusion has demonstrated experimentally and clinically its superiority over the other proposed protective techniques.

Staged total exclusion of the aorta for chronic type B aortic dissection

Hybrid techniques using extra-anatomic bypass of critical aortic branches to enable endovascular treatment of complex aortic pathology have been previously described. A staged endograft repair of a complex, chronic Stanford type B aortic dissection with aneurysmal degeneration is reported in a 50-year-old man. The aneurysmal portion of the dissection extended from the distal arch to both common iliac arteries and was covered with an endograft from the ascending aorta to both external iliac arteries. Aortic arch branches, visceral, and renal arteries were bypassed using open technique. The patient had no neurologic complications. This case report illustrates the feasibility of the hybrid technique in selected high-risk patients when confronted with complex aortic pathology.

[Open surgery and endovascular treatment on the descending thoracic aorta: 15 years' experience]

OBJECTIVE

Outcomes of surgical treatment of the descending thoracic aorta have improved markedly, although high associated morbidity and mortality continue to be a concern. Endovascular treatments are therefore attractive alternatives to open surgery. We compared outcomes of endovascular treatment to outcomes of open surgery on both aortic segments.

MATERIAL AND METHODS

Retrospective study of patients treated for descending thoracic and thoracoabdominal aorta disease by means of open surgery or endovascular treatment in our hospital between 1995 and 2009. We analyzed preoperative characteristics, intraoperative variables, and postoperative results in both groups.

RESULTS

We retrieved the cases of 22 patients, 10 who underwent open surgery and 12 who received endovascular treatment. Surgery was indicated to treat aneurysm (40%), aortic dissection (30%), or both (30%) in the open surgery group. In the endovascular treatment group, 66.7% had aneurysm, 33.3% dissection, and 0% both. Trauma was involved in 20% of the open surgeries and 16.7% of the endovascular procedures. Forty percent of the open surgery cases and 16.2% of the endovascular interventions were emergencies. Patient age was the only statistically significant between-group difference in preoperative characteristics. Postoperative complication rates were similar. Significant differences were observed in duration of surgery, lengths of critical care unit and total hospital stays, and intubation time (P < .05).

CONCLUSIONS

The incidence of postoperative complications in the group of patients undergoing open surgery on the descending thoracic aorta was similar to incidences reported by other hospitals with moderate caseloads. A trend toward reduced morbidity and mortality in the endovascular treatment group was observed, and this group had significantly shorter times of intubation and lengths of critical care unit and hospital stays.

Female patients undergoing TEVAR may have an increased risk of postoperative spinal cord ischemia

BACKGROUND

There is a paucity of literature regarding thoracic endovascular aneurysm repair (TEVAR) in women. We report our institutional experience with TEVAR.

METHODS

Retrospective chart review was performed from 2004 to 2008. TEVAR was performed in 59 patients; 29 (49%) were female.

RESULTS

Mean age was 73.5 years. Mean thoracic aortic aneurysm (TAA) diameter was larger for women (5.9 cm vs 4.7 cm). A trend toward an increase in paraplegia was noted in women, 10.3% vs 4.8%. This may be related to increase in length of aortic coverage in women, 18.2 cm vs 15.2 cm (P < .05).

CONCLUSION

TEVAR in women is safe and effective. The length of aortic coverage is greater in women, which may be related to larger aneurysms and more diffuse disease. This may be associated with a concerning increase in postoperative paraplegia. Women undergoing TEVAR should be considered for prophylactic maneuvers to prevent spinal cord ischemia (SCI), including minimizing length of coverage.

Intrathecal lactate concentration and spinal cord injury in thoracoabdominal aortic surgery

OBJECTIVE

The aim of this study was to evaluate the role of lactate as an early predictor of spinal cord injury during thoracoabdominal aortic aneurysm repair.

DESIGN

Observational study.

SETTING

University hospital.

PARTICIPANTS

Sixteen consecutive patients (10 men and 6 women) scheduled to undergo thoracoabdominal aortic aneurysm repair were enrolled in the study. All patients were affected by atherosclerotic aneurysmal pathology.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

During surgery, the authors simultaneously withdrew samples of cerebrospinal fluid and arterial blood to evaluate pO(2), pCO(2), pH, and lactate concentration. Samples were collected at 5 fixed times during and after surgery: T1 (before aortic cross-clamping), T2 (15 minutes after clamping), T3 (just before unclamping), T4 (end of surgery), and T5 (4 hours after the end of surgery). Lactate levels in cerebrospinal fluid rose consistently during aortic cross-clamping (T1 = 1.89 mmol/L, T2 = 2.21 mmol/L, T3 = 2.88 mmol/L, T4 = 3.655 mmol/L, and T5 = 3.16 mmol/L). Lactate concentrations in the cerebrospinal fluid were significantly higher in the 4 patients who developed neurologic injury, even at T1 (before surgery), than in those who did not end in spinal cord injury with the 4 highest values belonging to the 4 patients who later developed spinal cord injury.

CONCLUSIONS

This study has the potential to elucidate the time course of early lactate level elevation during thoracoabdominal aortic aneurysm repair and its clinical use in predicting the development of postoperative spinal cord injury.

Paraparesis after thoracic stent-graft relining for an unrecognized type III endoleak

BACKGROUND

We examined the reasons for missing a type III endoleak on conventional imaging and the pathophysiology of paraparesis after relining this stent graft.

METHODS AND RESULTS

A 46-year-old man was treated with a thoracic stent graft for thoracic rupture of a chronic type B thoracoabdominal dissection with aneurysm formation. In a second intervention, retrograde revascularization of the visceral and renal arteries was performed in combination with insertion of an abdominal stent graft. After initial shrinkage of the aneurysmal sac, the thoracic aortic diameter started increasing again. Consecutive three-phase helical computed tomographic scans did not reveal any endoleak. Because of unbearable back pain, an open surgical exploration was performed. This showed a type III endoleak. Relining of the thoracic stent graft was performed, but paraparesis developed.

CONCLUSION

In patients with unexplained increase of the aneurysmal sac contrast-enhanced magnetic resonance imaging could help to illuminate the underlying endoleak. The collateral network concept can explain spinal cord injury by even minor hemodynamic changes.