Paraplegia after extensive thoracic and thoracoabdominal aortic aneurysm repair: Does critical spinal cord ischemia occur postoperatively?

Combined open and endovascular treatment of thoracoabdominal aortic pathologies: a systematic review and meta-analysis

BACKGROUND

A combined open-endovascular technique has emerged as an alternative treatment option for thoracoabdominal pathologies. However, reported experiences from various medical centers have been contradictory and heterogeneous. The aim of this study is to assess the mortality rate and various complication rates associated with this approach.

METHODS

An electronic health database search was performed on all articles published up to March of 2012 describing combined open-endovascular repair of thoracoabdominal pathologies. Studies were included in the meta-analysis if they had ≥10 patients and reported the basic outcome criteria. End points of the meta-analysis were defined as primary technical success, endoprosthesis related complications, 30-day/in-hospital mortality, symptoms of spinal cord ischemia (SCI) and irreversible paraplegia, permanent renal function impairment, and other major complications.

RESULTS

Fourteen studies were deemed eligible for this meta-analysis with a total of 528 patients (68.0% male, mean age 70.5 years). The mean follow-up period was 34.2 months. The pooled estimate for primary technical success and visceral graft patency was 95.4% and 96.5% respectively. An endoleak developed in 106 (21.1%) patients in whom both stages had been completed. The pooled rate for symptomatic SCI was 7.0% and for irreversible paraplegia 4.4%. The pooled proportion for permanent renal failure was 7.0% and for mesenteric ischemia 4.5%. Prolonged respiratory support and cardiac complications were observed in a pooled rate of 7.8% and 4.6% respectively. The meta-analysis for 30-day/in-hospital mortality revealed a pooled rate of 14.3%.

CONCLUSIONS

Although the hybrid technique for thoracoabdominal aortic pathology provides a less invasive approach, the technique is still associated with a considerable morbidity and mortality rates. High risk patients unfit to withstand open repair, are equally likely to suffer significant complications with the hybrid procedure. The choice of the optimal treatment strategy for thoracoabdominal pathologies should be carefully made on a patient to patient basis, assessing the clinical fitness and the anatomical suitability of each patient. The hybrid approach should be reserved for high volume centers with accumulated experience and high standards of perioperative management.

Mean perfusion pressure deficit during the initial management of shock--an observational cohort study

PURPOSE

It is unclear if blood pressure targets for patients with shock should be adjusted to pre-morbid levels. We aimed to investigate mean deficit between the achieved mean perfusion pressure (MPP) in vasopressor-treated patients and their estimated basal (resting) MPP, and assess whether MPP deficit has any association with subsequent acute kidney injury (AKI).

MATERIALS AND METHODS

Fifty-one consecutive, non-trauma patients, aged ≥40 years, with ≥2 organ dysfunction and requiring vasopressor≥4 hours were observed at an academic intensive care unit. Mean MPP deficit [=%(basal MPP-achieved MPP)/basal MPP] and % time spent with >20% MPP deficit were assessed during initial 72 vasopressor hours (T0-T72) for each patient.

RESULTS

Achieved MPP was unrelated to basal MPP (P=.99). Mean MPP deficit was 18% (95% CI 15-21). Patients spent 48% (95% CI 39-57) time with >20% MPP deficit. Despite similar risk scores at T0, subsequent AKI (≥2 RIFLE class increase from T0) occurred more frequently in patients with higher (>median) MPP deficit compared to patients with lower MPP deficit (56% vs 28%; P=.045). Incidence of subsequent AKI was also higher among patients who spent greater % time with >20% MPP deficit (P=.04).

CONCLUSIONS

Achieved blood pressure during vasopressor therapy had no relationship to the pre-morbid basal level. This resulted in significant and varying degree of relative hypotension (MPP deficit), which could be a modifiable risk factor for AKI in patients with shock.

Optimal treatment for patients with chronic Stanford type B aortic dissection: endovascularly, surgically or both?

OBJECTIVES

Patients with chronic Stanford type B aortic dissections (TBAD) are traditionally treated medically, but some of the affected thoracic and thoracoabdominal aortic segments progress to large aneurysms with a significant risk of rupture. The purpose of this study is to retrospectively evaluate, with an 'all-comers' approach, the survival and the outcome of patients following thoracic endovascular aortic repair (TEVAR) or conventional open surgery for chronic TBAD as a first-line therapy or a secondary option after failed medical treatment.

METHODS

Between January 2000 and May 2010, 80 consecutive patients (59 males, median age 63, inter-quartile range (IQR) 55-69) suffering from chronic TBAD were treated at our institution. Thirty-three were treated medically (Group A, median age: 65, IQR: 58.5-71.5), 32 received TEVAR (Group B, median age: 62, IQR: 54-67.5) and 15 patients underwent conventional open surgery (Group C, median age: 61, IQR: 54-66). The median follow-up was 42 months (range: 0.1-124.7) and 100% complete.

RESULTS

There were no significant differences with regard to age, gender and associated comorbidities between the treatment groups. The overall hospital mortality for chronic TBAD was 6.3% (n = 5); in-hospital mortalities for Groups A, B and C were 3.0, 6.2 and 13.4%, respectively. The incidence of major complications, such as paraplegia, malperfusion, renal failure and cardiac arrhythmia, did not significantly differ between the three groups. Postoperative stroke occurred more often after conventional open surgery (Group C: 13.3%; P = 0.07). Reintervention for TBAD pathology was required in Groups A, B and C in 12.1, 28.1 and 0%, respectively (P = 0.03). Secondary open surgery post-TEVAR was required in 7 cases (21.8%) with no postoperative paraplegia.

CONCLUSIONS

Open surgery for extensive thoracic and thoracoabdominal repair in chronic TBAD may be performed with acceptable early and mid-term outcomes. TEVAR for aortic complications in patients with chronic dissection may be successfully performed as a first-stage procedure in order to stabilize the patient and serve as a 'bridge' to secondary open surgery. However, close surveillance is mandatory for the timely detection of aneurysm enlargement, malperfusion or impending rupture after TEVAR.

Panax notoginsenoside produces neuroprotective effects in rat model of acute spinal cord ischemia-reperfusion injury

ETHNOPHARMACOLOGICAL RELEVANCE

Acute spinal cord ischemia-reperfusion injury (SCII) is associated with pathological changes, including inflammation, edema, and neuronal apoptosis. Panax notoginsenoside (PNS), an important traditional Chinese medicine, has shown a variety of beneficial effects, including homeostasis maintenance, anti-myocardial ischemia activities, and neuroprotective functions. However, whether it can produce neuroprotective effects in SCII and the underlying mechanisms remain largely elusive.

AIM OF THE STUDY

In the present study, we investigated the effects of PNS on neurological and histopathological changes after SCII as well as the underlying mechanisms.

MATERIALS AND METHODS

Sixty-four adult rats were randomly assigned into one of the four groups: the sham group, the ischemic group, the PNS group, and the Methylprednisolone group. A rat model of SCII was adopted from a commonly used protocol that was initially proposed by Zivin. Neurological function was evaluated with the Basso, Beattie and Bresnahan (BBB) locomotor rating scale. Histopathological changes were examined with hematoxylin and eosin staining as well as Nissl staining. Immunohistochemistry and Western blot were conducted to compare the changes in tumor necrosis factor-α, interleukin-1β, interleukin-10, aquaporin-4 (AQP-4), member 6 of the TNF receptor superfamily (Fas), and Fas ligand (FasL) in the spinal cord. Finally, neuronal apoptosis was measured by electron microscopy.

RESULTS

The BBB scores of the PNS-treated injured animals were significantly increased. The gross histopathological examination showed restored neuronal morphology and increased number of neurons after the PNS treatment. The PNS treatment decreased SCII-induced up-regulation of cytokine levels. In addition, PNS suppressed the increased expression of AQP-4 after SCII, suggesting an anti-edema effect. Finally, PNS treatment inhibited injury-induced apoptosis and reduced the expression levels of apoptosis-related proteins, Fas and FasL, confirming its anti-apoptosis effects against SCII.

CONCLUSION

The current findings suggest that PNS produces robust neuroprotective effects in spinal cord ischemia-reperfusion injury, and this role may be mediated by its anti-inflammation, anti-edema, and anti-apoptosis actions.

Hybrid Open Endovascular Technique for Aortic Thoracoabdominal Pathologies

Background—

Many authors using a hybrid debranching strategy for the treatment of thoracoabdominal pathologies have reported disappointing results and the initial enthusiasm for the technique has given way to criticism and ambiguity. The aim of the present meta-analysis study was to assess the safety and efficacy of the technique in patients with thoracoabdominal aortic aneurysms or other aortic pathologies.

Methods and Results—

A multiple electronic search was performed on all articles describing hybrid open endovascular repair. Separate meta-analyses were conducted for technical success, visceral graft patency, spinal cord ischemia symptoms, renal insufficiency, and other complications as well as 30-day/in-hospital mortality.

Nineteen publications with a total of 507 patients were analyzed. The pooled estimates for primary technical success and visceral graft patency were 96.2% (95% CI, 93.5%–98.2%) and 96.5% (95% CI, 95.2%–97.8%) respectively. A pooled rate of 7.5% (95% CI, 5.0%–11.0%) for overall spinal cord ischemia symptoms was observed; whereas for irreversible paraplegia the pooled rate was 4.5% (95% CI, 2.5%–7.0%). The pooled estimate for renal failure was 8.8% (95% CI, 3.9%–15.5%). The pooled 30-day/in-hospital mortality rate was 12.8% (95% CI, 8.6%–17.0%). During the mean follow-up period of 34.5 (95% CI, 31.5–37.5) months, a total of 119 endoleaks were identified in 111 patients (22.7%).

Conclusions—

The repair of thoracoabdominal pathologies by means of hybrid procedures in patients who are poor surgical candidates is still associated with significant morbidity and mortality rates. Future studies may substantiate whether the technique is amenable to amelioration and improvement.

Ischemic preconditioning ameliorates spinal cord ischemia-reperfusion injury by triggering autoregulation

OBJECTIVE

The mechanism underlying ischemic preconditioning (IPC) protection against spinal cord ischemia-reperfusion (I/R) injury is unclear. We investigated the role of spinal cord autoregulation in tolerance to spinal cord I/R injury induced by IPC in a rat model.

METHODS

Sprague-Dawley rats were randomly assigned to four groups. IPC (P) group animals received IPC by temporary thoracic aortic occlusion (AO) with a 2F Fogarty arterial embolectomy catheter (Baxter Healthcare, Irvine, Calif) for 3 minutes. The I/R injury (I/R) group animals were treated with blood withdrawal and temporary AO for 12 minutes, and shed blood reinfusion at the end of the procedures. The P+I/R animals received IPC, followed by 5 minutes reperfusion, and then I/R procedures for 12 minutes. Sham (S) group animals received anesthesia and underwent surgical preparation, but without preconditioning or I/R injury. Neurologic function on postprocedure days 1, 3, 5, and 7 was evaluated by Tarlov scoring. Lumbar segments were harvested for histopathologic examination on day 7. To evaluate the role of autoregulation in IPC, spinal cord blood flow and tissue oxygenation were continuously monitored throughout the procedure duration.

RESULTS

The Tarlov scores in the I/R group were significantly lower than those in the S, P, and P+I/R groups on days 1, 3, 5, and 7 (P < .001). No significant differences were noted between the S, P, and P+I/R groups. The numbers of surviving motor neurons in the S, P, and P+I/R groups were significantly higher than those in the I/R group (P < .001); however, the number of surviving motor neurons did not differ between the S, P, and P+I/R groups. The P group exhibited higher spinal cord blood flow (P = .001-.043) and tissue oxygenation (P = .032-.043) within the first 60 minutes after reperfusion than the S group. The P+I/R group exhibited higher spinal cord blood flow (P = .016-.045) and tissue oxygenation (P = .001-.038) within the first 60 minutes after reperfusion than the I/R group.

CONCLUSIONS

IPC ameliorates spinal cord I/R injury in rats, probably mediated by triggering spinal cord autoregulation and improving local spinal cord blood flow and tissue oxygenation. This concept may be the new therapeutic targets in patients requiring aortic surgery.

The effect of adrenergic β(2) receptor agonist on paraplegia following clamping of abdominal aorta

INTRODUCTION

Surgical repair of an aortic aneurysm might be complicated by spinal cord injury and paraplegia. Since β-adrenoreceptor agonists showed neuroprotective effects, the study was designed to investigate the effect of clenbuterol on post-aortic clamping paraplegia and to identify if there is hyperemia associated with paraplegia.

MATERIAL AND METHODS

Thirty rabbits were divided into two groups: 15 control and 15 experimental (given clenbuterol 9 mg in drinking water 24 h prior to surgery). All the animals were subjected to laparotomy whereas the abdominal aorta was identified. Using a vascular clamp, the abdominal aorta was clamped just distal to the renal arteries. Abdominal aortic blood flow was recorded with a transonic flow meter. The neurological assessment was made according to Tarlov's Neurological Scale upon recovering from anesthesia. Anal sphincter tonus and bladder sphincter function were also checked.

RESULTS

Four rabbits (2 control and 2 experimental) developed complete paraplegia within 30 min of cross-clamping of the aorta. Of the 13 controls, 77% developed paraplegia, and of the 13 experimental rabbits administered clenbuterol 24 h prior to surgery with 22 min of aortic cross-clamping, 38% developed paraplegia The rabbits which did not develop paraplegia had a minimal increase in aortic blood flow, whereas the rabbits which developed paraplegia had a significant increase in aortic blood flow measurements after aortic decamping.

CONCLUSIONS

Post-aortic clamping paraplegia is associated with hyperemia and clenbuterol has a significant neuroprotective effect, obviously by preventing an increase in aortic blood flow following unclamping.

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.

The collateral network concept: remodeling of the arterial collateral network after experimental segmental artery sacrifice

OBJECTIVE

A comprehensive strategy to prevent paraplegia after open surgical or endovascular repair of thoracoabdominal aortic aneurysms requires a thorough understanding of the response of the collateral network to extensive segmental artery sacrifice.

METHODS

Ten Yorkshire pigs underwent perfusion with a low-viscosity acrylic resin. With the use of cardiopulmonary bypass, 2 animals each were perfused in the native state and immediately, 6 hours, 24 hours, and 5 days after sacrifice of all segmental arteries (T4-L5). After digestion of surrounding tissue, the vascular cast of the collateral network underwent analysis of arterial and arteriolar diameters and the density and spatial orientation of the vasculature using light and scanning electron microscopy.

RESULTS

Within 24 hours, the diameter of the anterior spinal artery had increased significantly, and within 5 days the anterior spinal artery and the epidural arterial network had enlarged in diameter by 80% to 100% (P < .0001). By 5 days, the density of the intramuscular paraspinous vessels had increased (P < .0001), a shift of size distribution from small to larger arterioles was seen (P = .0002), and a significant realignment of arterioles parallel to the spinal cord had occurred (P = .0005).

CONCLUSIONS

Within 5 days after segmental artery occlusion, profound anatomic alterations in the intraspinal and paraspinous arteries and arterioles occurred, providing the anatomic substrate for preservation of spinal cord blood flow via collateral pathways.

Open repair of extensive thoracoabdominal and thoracic aneurysm: a preliminary single-center experience with femorofemoral distal aortic perfusion with oxygenator and without cerebrospinal fluid drainage

Thoracoabdominal aortic aneurysms (TAAA) and extensive thoracic descending aortic aneurysms (TDA) are not accessible through standard endovascular treatment. Fenestrated and branched endograft technology was developed rapidly without widespread application. The aim of this study was to review our open repair (OR) experience of TAAA and TDA. A total of 28 patients who underwent elective OR of TAAA or TDA between January 2001 and January 2009 were analyzed retrospectively. The mean age of the patients was 65.5 years (three women). The anatomic locations of the aneurysms were as follows: six in thoracic descending aorta and 22 in thoracoabdominal aorta (14 TAAA I, two TAAA II, six TAAA III). TDA (40 patients) available for ordinary endovascular treatment and TAAA IV (35 patients) were excluded from this study. To focus on spinal cord vascularization, 25 patients were submitted for angiography. Three patients suffering from back pain required quick treatment and were excluded from angiographic investigations. Angiography procedures were contributive in 23 patients (92%). Surgical repairs were driven through left thoraco-phreno-laparotomy, with the adjunct of distal aortic perfusion (femorofemoral bypass) including the use of an oxygenator and sequential aortic cross-clamping. Cerebrospinal fluid drainage was not used in this experience. The 30-day mortality rate was 14.3% (four of 28 patients): one multiorgan failure and three pulmonary sepsis. An immediate postoperative paraplegia occurred, affecting a patient with TDA who was previously submitted for infrarenal aorta replacement, despite angiographic identification and revascularization of intercostal artery destined to spinal artery. The 1-year survival rate was 82.1% (23 of 28 patients). In the preliminary experience of this study, OR of extensive TAAA and TDA with distal aortic perfusion and an oxygenator without use of cerebrospinal fluid drainage was associated with a significant perioperative mortality rate (14.2%), a reasonable rate of paraplegia (3%), and 1-year survival rate of 82.1%.

Can intraoperative motor-evoked potentials predict all the spinal cord ischemia during moderate hypothermic beating heart descending thoracic or thoraco-abdominal aortic surgery?

BACKGROUND AND AIM OF THE STUDY

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.

METHODS AND RESULTS

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.

CONCLUSIONS

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.

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.

Beneficial effects of hydrogen gas against spinal cord ischemia-reperfusion injury in rabbits

Recently, hydrogen gas (H₂) is reported to be a new therapeutic agent in organ damage induced by ischemia-reperfusion (I/R). The present study was designed to investigate the beneficial effects of H₂ against spinal cord I/R injury and its associated mechanisms. Spinal cord ischemia was induced by infrarenal aortic occlusion for 20 min in male New Zealand white rabbits. Treatment with 1%, 2% or 4% H₂ inhalation was given from 10 min before reperfusion to 60 min after reperfusion (total 70 min). Here, we found that I/R-challenged animals showed significant spinal cord damage characterized by the decreased numbers of normal motor neurons and hind-limb motor dysfunction, which was significantly improved by 2% and 4 % H₂ treatment. Furthermore, we found that the beneficial effects of H₂ treatment against spinal cord I/R injury were associated with the decreased levels of oxidative products [8-iso-prostaglandin F2α (8-iso-PGF2α) and malondialdehyde (MDA)] and pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and high-mobility group box 1 (HMGB1)], as well as increased activities of antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)] in serum and spinal cord. In addition, H₂ treatment reduced motor neuron apoptosis in the spinal cord of this model. Thus, H₂ inhalation may be an effective therapeutic strategy for spinal cord I/R damage.

[Livedoid erythema of the lower back revealing thrombosed abdominal aortic aneurysm]

BACKGROUND

We report the case of a patient presenting a very painful livedo of the lower back as well as paraparesis revealing a complicated abdominal aortic aneurysm.

PATIENTS AND METHODS

A 61-year-old man was referred to our emergency unit for sudden lower back pain and weakness of the lower limbs. He had a large and very painful livedo racemosa on the lower back as well as partial neurological deficit of the lower limbs. Abdominal CAT revealed a bulky thrombosed infrarenal aortic aneurysm. Despite surgery, ischaemia worsened, leading to cutaneous then muscular and visceral necrosis, followed by death.

DISCUSSION

Livedo racemosa of the lower limbs may be the consequence of thrombosis or embolism resulting from an abdominal aortic aneurysm. Livedo racemosa on other skin areas is uncommon but may be due to the same physiopathology. Neurological deficit is occasionally associated with a complicated abdominal aortic aneurysm or with surgical treatment thereof. However, to our knowledge, livedo on the back associated with neurological deficit has not yet been reported. Such an association should prompt practitioners to screen for a thrombosed aortic aneurysm. Furthermore, this condition is also likely to carry a poor prognosis because of the proximal secondary location of the thrombotic phenomenon, involving the lumbar arteries, which supply the medullar, cutaneous and muscular arteries.

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.

Occlusion of the left subclavian artery with stent grafts is safer with protective reconstruction

BACKGROUND

Safe fixation of endovascular stent grafts in thoracic aortic disease often requires covering of the left subclavian artery (LSA) with the stent graft. It is controversial whether this occlusion can be done without additional risk of ischemic complications.

METHODS

In 102 patients treated with endovascular stent grafts, the LSA was covered. In a nonrandomized clinical practice, unprotected occlusion of the LSA was performed in 63 patients (61%), whereas 39 patients underwent extrathoracic subclavian to carotid artery revascularization before (n = 28) or concomitantly with (n = 11) the endovascular procedure.

RESULTS

Left cerebral ischemia occurred in 11% of the unprotected group and in 5% of the protected group. The difference was not statistically significant. The difference in spinal cord ischemia was insignificant owing to the low incidence in general, but the covered length of the aorta was significantly longer in the protected group. Arm ischemia after unprotected LSA occlusion occurred in 25%.

CONCLUSIONS

The interpretation of the results remains speculative because many factors contribute to left cerebral ischemia. However, in terms of overall complications, there is a significant difference in favor of the group protected by revascularization of the LSA either before or simultaneously with stent grafting. Arm ischemia is mostly mild and can be managed secondarily. Subclavian revascularization is associated with relatively low risk and should be considered in advance, at least when extended covering of the thoracic aorta is intended.

Off-pump extraanatomic bypass from the ascending to the descending aorta for re-operation of interrupted aortic arch in an adolescent

The appearance of re-stenosis after repair of an interrupted aortic arch may be a surgical challenge due to adhesions. Here, we describe an approach using off-pump coronary artery bypass grafting techniques to reach the descending aorta through a median sternotomy in a patient with aortic arch stenosis after conduit repair. The 17-year-old patient with diagnoses of interrupted aortic arch and ventricular septal defect presented after two previous operations (one left lateral thoracotomy and one median sternotomy) with a stenosed vascular graft between ascending and descending aorta. Surgery was done via re-sternotomy without cardio-pulmonary bypass. An extraanatomic graft was used to connect ascending and descending aorta. When performing the distal anastomosis, the heart was exposed using a standard suction device. This case demonstrates that the use of modern techniques may facilitate surgical approaches dramatically. In our opinion the above-described technique is the first choice for all patients requiring arch repair following multiple previous operations, performed via sternotomy and thoracotomy.

Endovascular repair for a descending thoracic aortic aneurysm with a stent-graft covering the celiac artery: report of two cases

An adequate landing zone for fixation and sealing is necessary for endovascular aneurysm repair (EVAR). This report presents two cases of a successful EVAR for thoracic aortic aneurysms (TAA) with a stent-graft covering the celiac artery (CA) to secure a distal landing zone. Case 1 was a 61-year-old man with a chronic traumatic descending TAA 12 mm away from the CA. Case 2 was a 79-year-old man with a descending TAA proximal to the CA. Preoperative angiography and computed tomography (CT) scan revealed a normal visceral blood flow including the peripancreatic arteries. Endovascular aneurysm repair with coverage of the CA was performed in both cases. Angiography after the EVAR demonstrated good blood flow to the CA branches via the peripancreatic arteries and a CT scan showed thrombosed aneurysms. Both patients were discharged without any abdominal symptoms. Endovascular aneurysm repair with a stent-graft covering the CA may therefore be an acceptable endovascular approach in treating selected TAA patients with a limited distal landing zone.

Spinal cord blood flow and ischemic injury after experimental sacrifice of thoracic and abdominal segmental arteries

OBJECTIVE

Spinal cord blood flow (SCBF) after sacrifice of thoracoabdominal aortic segmental arteries (TAASA) during thoracoabdominal aortic aneurysm (TAAA) repair remains poorly understood. This study explored SCBF for 72 h after sacrifice of all TAASA.

METHODS

Fourteen juvenile Yorkshire pigs underwent complete serial TAASA sacrifice (T4-L5). Six control pigs underwent anesthesia and cooling to 32 degrees C with no TAASA sacrifice. In the experimental animals, spinal cord function was continuously monitored using motor evoked potentials (MEPs) until 1h after clamping the last TAASA. Fluorescent microspheres enabled segmental measurement of SCBF along the entire spinal cord before, and 5 min, 1 h, 5 h, 24 h and 72 h after complete TAASA sacrifice. A modified Tarlov score was obtained for 3 days after surgery.

RESULTS

All the pigs with complete TAASA sacrifice retained normal cord function (MEP) until 1h after TAASA ligation. Seven pigs (50%) with complete TAASA sacrifice recovered after 72 h; seven pigs suffered paraparesis or paraplegia. Intraoperatively, and until 1h postoperatively, SCBF was similar among the three groups along the entire cord. Postoperatively, SCBF did not decrease in any group, but significant hyperemia occurred at 5h in controls and recovery animals, but did not occur in pigs that developed paraparesis or paraplegia in the T8-L2 segments (p=0.0002) and L3-S segments (p=0.0007). At 24h, SCBF remained marginally lower from T8 caudally; at 72h, SCBF was similar among all groups along the entire cord. SCBF in the segments T8-L2 at 5h predicted functional recovery (p=0.003).

CONCLUSIONS

This study suggests that critical spinal cord ischemia after complete TAASA sacrifice does not occur immediately (intraoperatively), but is delayed 1-5h or longer after clamping, and represents failure to mount a hyperemic response to rewarming and awakening. The short duration of low SCBF associated with spinal cord injury suggests that hemodynamic and metabolic manipulation lasting only 24-72 h may allow routine preservation of normal cord function despite sacrifice of all TAASA secondary to surgical or endovascular repair of large TAAA.