Safety and efficacy of hypothermic cardiopulmonary bypass and circulatory arrest for operations on the descending thoracic and thoracoabdominal aorta

Utility of motor-evoked potentials in contemporary open thoracoabdominal aortic repair

OBJECTIVE

Paraplegia remains one of the major complications of contemporary open thoracoabdominal aortic aneurysm (TAAA) repair. Intraoperative motor-evoked potentials (MEPs) act as a surrogate measure for spinal cord homeostasis. The purpose of this study was to evaluate the results of intraoperative neuromonitoring in contemporary TAAA repair and its association with postoperative spinal cord ischemia (SCI).

METHODS

Patients who underwent open type 2 or 3 TAAA or completion aortic repair using intraoperative neuromonitoring were identified between May 2006 and November 2023. Patient demographics, comorbidities, indication for the procedure, procedural details, and outcomes were recorded. The groups were divided based on type of repair, and univariate statistics were then used to evaluate the association of these metrics vs the type of repair.

RESULTS

Seventy-nine patients underwent open type 2 (N = 41) and 3 (N = 23) TAAA and completion aortic (N = 15; open in 14 and endovascular in 1) repairs by a single surgeon. The cohort was predominantly male (N = 48, 60.8%) with a mean age of 52.5 ± 16.2 years. There was a high incidence of hypertension (N = 53, 67.1%), smoking history (N = 42, 53.1%), and connective tissue disorders (N = 37, 46.8%). Operative indications included dissection-related (N = 50, 63.3%) and degenerative (N = 26, 32.9%) TAAA and dissection-related malperfusion (N = 3, 3.8%). Left heart bypass was often (N = 73, 92.4%) used for distal aortic perfusion, and cerebrospinal fluid drainage (N = 77, 97.5%) was a common adjunct. MEPs were classified as no change (N = 43, 54.4%), reversible change (N = 26, 32.9%), irreversible change (N = 4, 5.1%), and unreliable (N = 6, 7.6%). MEP changes were predominantly bilateral (N = 70, 88.6%) and occurred most often during repair of the abdominal aortic segment (N = 13, 16.5%). The median number of replaced vertebral levels was associated with MEP changes (P = .013). SCI was only observed in repairs greater than 6 replaced vertebral levels with an overall frequency of 17.7%. It was most prevalent in completion aortic repairs (26.7%). Immediate and delayed SCI occurred in 10.1% and 7.6% of patients, respectively; it was most commonly (71.8%) reversible. Permanent paraplegia occurred in four patients (5.1%), with equal immediate and delayed onsets. MEPs demonstrated poor sensitivity (53.9%) and specificity (62.3%) for SCI; however, there was a high negative predictive value (86.4%) in this population. In-hospital mortality occurred in five (6.3%) patients.

CONCLUSIONS

No changes in intraoperative MEPs are highly predictive of spinal cord homeostasis. The number of replaced vertebral levels and previous aortic repair should guide intraoperative neuroprotective measures including intercostal reimplantation and should take precedence over intraoperative monitoring, especially when MEP changes occur.

Simultaneous upper and lower body perfusion using hypothermia during thoracoabdominal aortic surgery

BACKGROUND

In open thoracoabdominal aortic aneurysm (TAAA) repair, we have been performing vascular reconstruction under moderate to deep hypothermia and assisted circulation using simultaneous upper and lower body perfusion. This method is effective for protecting the spinal cord and the brain, heart, and abdominal organs and for avoiding lung damage.

METHODS

TAAA repair was performed under hypothermia at 20-28 °C in 18 cases (Crawford type I in 0 cases, type II in 5, type III in 3, type IV in 4, and Safi V in 6) between October 2014 and January 2023. Cardiopulmonary bypass was conducted by combined upper and lower body perfusion, with perfusion both via the femoral artery and either transapically or via the descending aorta or the left brachial artery.

RESULTS

The ischemic time for the artery of Adamkiewicz and the main segmental arteries was 40-124 min (75 ± 33 min). No spinal cord ischemic injury or brain or heart complications occurred. One patient with postoperative right renal artery occlusion and one with an infected aneurysm required tracheostomy, but the intubation time for the other 16 was 32 ± 33 h. The duration of postoperative intensive care unit stay was 6.5 ± 6.2 days, the length of hospital stay was 29 ± 15 days, and no in-hospital deaths occurred.

CONCLUSIONS

Simultaneous upper and lower body perfusion under moderate to deep hypothermia during thoracoabdominal aortic surgery may avoid not only spinal cord injury, but also cardiac and brain complications.

Open surgical replacement of the descending aorta: single-center experience

Background

This study presents a single center's experience and analyzes clinical outcomes following elective open surgical descending aortic replacement.

Methods

Between January 2000 and August 2019, 96 patients with mean age 64 years (range, 49.5-71 years) (62.5% (n=60) male) underwent elective descending aortic replacement due to aneurysm (n=60) or chronic dissection (n=36). Marfan syndrome was present in 12 patients (12.5%).

Results

In-hospital mortality rate was 3.1% (n= 3. 2 in the aneurysm group, 1 in the dissection group). New-onset renal insufficiency postoperatively with (creatinine ≥ 2.5 mg/dl) manifested in 10 patients (10.8%). One patient (1%) suffered from stroke, and paraplegia developed in 1 pts (1%). The median follow-up time was 7 years (IQR: 2.5-13 years). The 5- and 10-year survival rates were 70.8% and 50.7% respectively. We did not observe any early or late prosthetic graft infection. The Cox proportional hazards regression analysis identified age (HR: 1.044, 95% CI: 1.009-1.080, p-value: 0.014), diabetes (HR: 2.544, 95% CI: 1.009-6.413, p-value: 0.048), and chronic obstructive pulmonary disease (COPD) (HR: 2.259, 95% CI: 1.044-4.890, p-value: 0.039) as risk factors for late mortality.

Conclusions

This study showed that the elective open surgical replacement of the descending aorta can be achieved with excellent outcomes in terms of perioperative mortality and morbidity. Prosthetic graft is not a problem with open surgical descending aortic replacement, even in the long term.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-022-01443-x.

Neuroprotective Effects of Dexpanthenol on Rabbit Spinal Cord Ischemia/Reperfusion Injury Model

OBJECTIVE

Dexpanthenol (DXP) reportedly protects tissues against oxidative damage in various inflammation models. This study aimed to evaluate its effects on oxidative stress, inflammation, apoptosis, and neurological recovery in an experimental rabbit spinal cord ischemia/reperfusion injury (SCIRI) model.

METHODS

Rabbits were randomized into 5 groups of 8 animals each: group 1 (control), group 2 (ischemia), group 3 (vehicle), group 4 (methylprednisolone, 30 mg/kg), and group 5 (DXP, 500 mg/kg). The control group underwent laparotomy only, whereas other groups were subjected to spinal cord ischemia by aortic occlusion (just caudal to the 2 renal arteries) for 20 min. After 24 h, a modified Tarlov scale was employed to record neurological examination results. Malondialdehyde and caspase-3 levels and catalase and myeloperoxidase activities were analyzed in tissue and serum samples. Xanthine oxidase activity was measured in the serum. Histopathological and ultrastructural evaluations were also performed in the spinal cord.

RESULTS

After SCIRI, serum and tissue malondialdehyde and caspase-3 levels and myeloperoxidase and serum xanthine oxidase activities were increased (P < 0.05-0.001). However, serum and tissue catalase activity decreased significantly (P < 0.001). DXP treatment was associated with lower malondialdehyde and caspase-3 levels and reduced myeloperoxidase and xanthine oxidase activities but increased catalase activity (P < 0.05-0.001). Furthermore, DXP was associated with better histopathological, ultrastructural, and neurological outcome scores.

CONCLUSIONS

This study was the first to evaluate antioxidant, anti-inflammatory, antiapoptotic, and neuroprotective effects of DXP on SCIRI. Further experimental and clinical investigations are warranted to confirm that DXP can be administered to treat SCIRI.

Interventions to improve perioperative neurologic outcomes

PURPOSE OF REVIEW

Few outcomes in surgery are as important to patients as that of their neurologic status. The purpose of this review is to discuss and categorize the most common perioperative neurologic complications. We will also discuss strategies to help prevent and mitigate these complications for our patients.

RECENT FINDINGS

There are several strategies the anesthesiologist can undertake to prevent or treat conditions, such as perioperative neurocognitive disorders, spinal cord ischemia, perioperative stroke, and postoperative visual loss.

SUMMARY

A thorough understanding of threats to patients' neurologic well-being is essential to excellent clinical practice.

Left Atrial to Femoral Artery Full Cardiopulmonary Bypass: A Novel Technique for Descending and Thoracoabdominal Aortic Surgery

Left atrial-femoral artery (LA-FA) bypass with a centrifugal pump and no oxygenator is commonly used for descending and thoracoabdominal aortic (DTAA) operations, mitigating the deleterious effects of cross-clamping. We present our initial experience performing DTAA replacement under LA-FA (left-to-left) cardiopulmonary bypass (CPB) with an oxygenator. DTAA replacement under LA-FA bypass with an oxygenator was performed in 14 consecutive patients (CPB group). The pulmonary vein and femoral artery (or distal aorta) were cannulated and the full CPB machine were used, including oxygenator, roller pump, pump suckers, and kinetically enhanced drainage. The CPB group was compared with 50 consecutive patients who underwent DTAA replacement utilizing traditional LA-FA bypass without an oxygenator (LA-FA group). Perioperative data were collected and statistical analyses were performed. All CPB patients maintained superb cardiopulmonary stability. The pump sucker permitted immediate salvage and return of shed blood. Superb oxygenation was maintained at all times. High-dose full CPB heparin was reversed without difficulty. The CPB group required markedly fewer blood transfusions than the LA-FA group (2.21 vs. 5.88 units, p  < 0.004). The 30-day mortality rate was 7.1% ( n  = 1) and there were no paraplegia cases in the CPB group versus 7 (14%) deaths and 3 (6%) paraplegia cases in the LA-FA group. Traditional LA-FA bypass without an oxygenator avoids high-dose heparin. In the present era, heparin reversal is more secure. Our experience finds that the novel application of LA-FA CPB with an oxygenator is safe and suggests improved hemodynamics (immediate return of shed blood) and a hemostatic advantage (avoidance of loss of coagulation factors in the cell saver).

Direct Monitoring of Reconstructed Segmental Arterial Pressure during Deep Hypothermic Thoracoabdominal Aortic Aneurysm Surgery

Deep hypothermia in thoracoabdominal aortic aneurysm operations is considered extremely useful for ensuring sufficient time to reconstruct the segmental arteries feeding the spinal cord. However, because the amplitude of motor evoked potentials (MEPs) decrease or disappear during deep hypothermia, feasible methods for assessing spinal cord circulation have not yet been reported. Performing additional segmental arterial reconstructions that rely on MEPs is also impractical. In the present case, to ascertain spinal cord circulation under deep hypothermia, we intraoperatively measured the reconstructed segmental arterial pressure in real time and investigated whether sufficient spinal cord blood flow had been attained.

Transapical aortic perfusion using a deep hypothermic procedure during descending thoracic or thoracoabdominal aortic surgery

BACKGROUND

In descending thoracic aortic aneurysm (DTAA) or thoracoabdominal aortic aneurysm (TAAA) surgery, though proximal anastomosis using deep hypothermic circulatory arrest (DHCA) is often selected, there are issues surrounding brain and heart protection. In this study, the usefulness of concomitant upper body perfusion via transapical aortic cannulation during deep hypothermic surgery was examined.

METHODS

Between October 2014 and May 2019, 5 patients (Crawford extent II chronic dissection, N.=3; extent IV aneurysms, N.=1; DTAA, N.=1) underwent DTAA/TAAA repair under deep hypothermia using transapical aortic perfusion. A proximal anastomosis and artery of Adamkiewicz (AKA) reconstruction were performed under continuous perfusion of the upper and lower body at 20 °C.

RESULTS

The time from aortic cross-clamping to proximal anastomosis was 69±33 minutes, and it took 86±47 minutes to AKA reperfusion. There was no spinal cord ischemic injury or brain or heart complications. One patient required tracheostomy, and the average postoperative intubation time for the other patients was 57±52 hours. All patients were discharged, and the average postoperative hospital stay was 25.6±8.1 days.

CONCLUSIONS

Concomitant upper body perfusion by the transapical aortic approach contributes to avoidance of brain and heart complications and maintaining spinal cord circulation under deep hypothermic DTAA/TAAA surgery.

Early Outcomes After Thoracoabdominal Aortic Aneurysm Repair With Hypothermic Circulatory Arrest

BACKGROUND

A variety of intraoperative strategies are currently used for organ protection during open operations on the thoracoabdominal aorta. We report our experience with cardiopulmonary bypass and hypothermic circulatory arrest as the primary modality for organ protection, focusing on the early outcomes.

METHODS

During a 30-year interval, 285 patients underwent thoracoabdominal aortic aneurysm repair with the use of cardiopulmonary bypass with an interval of circulatory arrest (72 Crawford extent I, 107 extent II, 104 extent III, and 2 extent IV). Degenerative aneurysms were present in 72.6% and aortic dissections in 26.4% of patients. Emergent operations for rupture or acute dissection were required in 6.7% of the patients.

RESULTS

Thirty-day mortality was 7.4% and was highest for the Crawford extent II and extent III patients (10.3% and 6.7%, respectively). Permanent paralysis or paraplegia occurred in 15 patients (5.3%). The rates were highest for the extent II and extent III patients (6.5% and 6.7%, respectively). Cerebrospinal fluid drainage had no impact on the development of spinal cord injury, and implantation of intercostal/lumbar arteries had a protective effect only in patients with extent II repair. Stroke occurred in 4.2% of patients and renal failure that required dialysis occurred in 6.2%. One-year actual survival was 90.4%.

CONCLUSIONS

Our extended experience with this technique confirms its safety and effectiveness when used on a routine basis. The rates of spinal cord injury and permanent renal failure are among the lowest reported in the literature. Particularly favorable outcomes were observed in younger patients and patients undergoing elective operations.

Surgical Repair of Distal Aortic Arch Aneurysm With Distal Extension: Sternotomy Versus Thoracotomy

BACKGROUND

There is no consensus as to whether a median approach or a lateral approach is better for distal aortic arch aneurysms with distal extensions. The aim of this study was to compare clinical outcomes of these two approaches for distal aortic arch aneurysms with distal extensions.

METHODS

From January 2001 to December 2017, 212 consecutive patients with distal aortic arch aneurysms with distal extensions underwent surgery using different approaches: hemiarch and descending thoracic aneurysm replacement through thoracotomy (group 1, n = 91); and total arch and descending thoracic aneurysm replacement through sternotomy (group 2, n = 121). Early and late outcomes were compared using scores and inverse probability of treatment adjustments to reduce treatment selection bias.

RESULTS

The in-hospital mortality was 9.89% (9 of 91) in the thoracotomy group and 2.48% (3 of 121) in the sternotomy group (p = 0.02). The sternotomy group had a lower incidence of permanent stroke (2.48%, 3 of 121) compared with the thoracotomy group (10.99%, 10 of 91, p = 0.01). After adjustment, patients who underwent thoracotomy were at a greater risk of hospital mortality (odds ratio 5.0, p = 0.01), permanent stroke (odds ratio 6.83, p < 0.01), and pneumonia (odds ratio 2.99, p = 0.04), compared with patients who underwent sternotomy. The overall survival at 10 years was 69.8% ± 7.0% for the thoracotomy group and 83.0% ± 5.0% for the sternotomy group (unadjusted p = 0.049, adjusted p = 0.034).

CONCLUSIONS

The sternotomy approach showed better outcomes in terms of operative mortality, stroke, and pneumonia, as well as long-term survival compared with the thoracotomy approach. These results suggested that the sternotomy approach was more appropriate for patients with distal aortic arch aneurysms with distal extensions.

Neuroprotective Strategies in Repair and Replacement of the Aortic Arch

Aortic arch surgery is a technical challenge, and cerebral protection during distal anastomosis is a continued topic of controversy and discussion. The physiologic effects of hypothermic arrest and adjunctive cerebral perfusion have yet to be fully defined, and the optimal strategies are still undetermined. This review highlights the historical context, physiological rationale, and clinical efficacy of various neuroprotective strategies during arch operations.

Sex-Related Differences Between Patients With Symptomatic Acute Aortic Dissection

We designed a retrospective cohort study to assess sex-related differences in clinical manifestations, incidence, and outcomes of patients with symptomatic acute aortic dissection (AAD). We collected clinical data from 2010 to 2015 of 400 patients with AAD. Patients' clinical characteristics, treatment, and outcomes were analyzed as a function of sex. Among 400 patients with AAD, the ratio of men to women was 3.18:1; the incidence of atherosclerosis was higher in women (P = 0.02). Dysphoria (P = 0.01), focal neurological deficits (P = 0.04), and pulse deficits (P = 0.03) were more frequent in men. Imaging findings revealed that pleural effusion (P < 0.01), celiac trunk involvement (P < 0.01), and superior mesenteric artery involvement (P = 0.02) were more frequent in men. Dissection-related pneumonia (P = 0.02), pulmonary atelectasis (P = 0.01), aortic intramural hematoma (P < 0.01), ischemic electrocardiographic changes (P = 0.03), and in-hospital complications such as myocardial ischemia (P = 0.03), hypoxemia (P < 0.01), cardiac tamponade (P = 0.01) occurred more frequently in women. Women with type A dissection had higher in-hospital mortality than men (P < 0.01). The presentation of AAD varies with a patient's sex. Women with AAD had clinical features different from men as follows: higher age of onset, more frequent inpatient complications, and higher in-hospital mortality. These findings may lead to a better understanding of aortic dissection in women that will improve their outcomes.

Spinal cord injury following thoracic and thoracoabdominal aortic repairs

Objective

To discuss the currently available approaches to prevent spinal cord injury during thoracic and thoracoabdominal aortic repairs.

Methods

We carried out a PubMed search up to 2013 using the Medical Subject Headings: “aortic aneurysm/surgery” and “spinal cord ischemia”; “aortic aneurysm, thoracic/surgery” and “spinal cord ischemia”; “aneurysm/surgery” and “spinal cord ischemia/cerebrospinal fluid”; “aortic aneurysm/surgery” and “paraplegia”. All 190 original articles satisfying our inclusion criteria were analyzed for incidence, predictors, and other pertinent variables related to spinal cord injury, and we compared the results in recent publications with those in earlier reports.

Results

The mean age of the 38,491 patients was 65.3 ± 4.9 years. The overall incidence of paraplegia and/or paraparesis was 7.1% ± 6.1% (range 0%–32%). The incidence of spinal cord injury before 2000, from 2001 to 2007, and 2008–2013 was 9.0% ± 6.7%, 7.0% ± 6.1%, and 5.9% ± 5.2%, respectively ( p = 0.019). Various predictors of spinal cord injury were identified, extent of disease being the most common. Modification of surgical techniques, use of adjuncts, and better understanding of spinal cord perfusion physiology were attributed to the decrease in postoperative spinal cord injury in recent years.

Conclusions

Spinal cord injury after thoracic and thoracoabdominal aortic repair poses a real challenge to cardiovascular surgeons. However, with evolving surgical strategies, identification of predictors, and use of various adjuncts over the years, the incidence of spinal cord injury after thoracic/thoracoabdominal aortic repair has declined. Embracing a multimodality approach offers a good insight into combating this grave complication.

Outcomes of open surgical repair of descending thoracic aortic disease

Background

To determine the predictors of clinical outcomes following surgical descending thoracic aortic (DTA) repair.

Methods

We identified 103 patients (23 females; mean age, 64.1±12.3 years) who underwent DTA replacement from 1999 to 2011 using either deep hypothermic circulatory arrest (44%) or partial cardiopulmonary bypass (CPB, 56%).

Results

The early mortality rate was 4.9% (n=5). Early major complications occurred in 21 patients (20.3%), which included newly required hemodialysis (9.7%), low cardiac output syndrome (6.8%), pneumonia (7.8%), stroke (6.8%), and multi-organ failure (3.9%). None experienced paraplegia. During a median follow-up of 56.3 months (inter-quartile range, 23.1 to 85.1 months), there were 17 late deaths and one aortic reoperation. Overall survival at 5 and 10 years was 80.9%±4.3% and 71.7%±5.9%, respectively. Reoperation-free survival at 5 and 10 years was 77.3%±4.8% and 70.2%±5.8%. Multivariable analysis revealed that age (hazard ratio [HR], 1.10; 95% confidence interval [CI], 1.05 to 1.15; p<0.001) and left ventricle (LV) function (HR, 0.88; 95% CI, 0.82 to 0.96; p<0.003) were significant and independent predictors of long-term mortality. CPB strategy, however, was not significantly related to mortality (p=0.49).

Conclusion

Surgical DTA repair was practicable in terms of acceptable perioperative mortality/morbidity as well as favorable long-term survival. Age and LV function were risk factors for long-term mortality, irrespective of the CPB strategy.

Surgical repair of descending thoracic and thoracoabdominal aortic aneurysm involving the distal arch: open proximal anastomosis under deep hypothermia versus arch clamping technique

BACKGROUND

Surgical repair of a descending thoracic and thoracoabdominal aortic aneurysm (DTA/TAAA) involving the distal arch is challenging and requires either deep hypothermic circulatory arrest (DHCA) or crossclamping of the distal arch. The aim of this study was to compare these 2 techniques in the treatment of DTA/TAAA involving the distal arch.

METHODS

From 1994 to 2012, 298 patients underwent open repair of DTA/TAAA through a left thoracotomy. One hundred seventy-four patients with distal arch involvement who were suitable for either DHCA (n=81) or arch clamping (AC; n=93), were analyzed. In-hospital outcomes were compared using propensity scores and inverse-probability-of-treatment weighting adjustment to reduce treatment selection bias.

RESULTS

Early mortality was 11.1% in the DHCA group and 8.6% in the AC group (P=.58). Major adverse outcomes included stroke in 16 patients (9.2%), low cardiac output syndrome in 15 (8.6%), paraplegia in 10 (5.7%), and multiorgan failure in 10 (5.7%). After adjustment, patients who underwent DHCA were at similar risk of death (odds ratio [OR], 1.14; P=.80) and permanent neurologic injury (OR, 0.95; P=.92) to those who underwent AC. Although prolonged ventilator support (>24 hours) was more frequent with DHCA than with AC (OR, 2.60; P=.003), DHCA showed a tendency to lower the risk of paraplegia (OR, 0.15; P=.057).

CONCLUSIONS

Compared with AC, DHCA did not increase postoperative mortality and morbidity, except for prolonged ventilator support. However, DHCA may offer superior spinal cord protection to AC during repair of DTA/TAAA involving the distal arch.

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.

Aortic arch occlusion technique using a balloon during open proximal anastomosis

We report a new aortic arch occlusion technique with a balloon for distal aortic arch repair via left thoracotomy using an open proximal method. Distal aortic arch repair via left thoracotomy sometimes causes brain infarction and perioperative myocardial infarction. That is because air or debris enters into coronary arteries and cervical branches and the left ventricle. Occlusion of the aortic arch using a balloon can prevent such perioperative complications.

Ruptured thoracic descending aortic aneurysm coexisting with DeBakey type IIIb aortic dissection

We have encountered a rare case of ruptured true thoracic aortic aneurysm coexisting with DeBakey type IIIb aortic dissection. The patient was a 67-year-old woman who had a past history of hypertension and cerebral infarction. She experienced DeBakey type IIIb acute aortic dissection, and initially conservative medical treatment was carried out. However, the patient suddenly went into shock, and emergency contrast-enhanced computed tomography revealed the presence of a ruptured true thoracic aortic aneurysm coexisting with the type IIIb dissection. Replacement of the descending aorta was performed through a left thoracotomy using circulatory arrest and deep hypothermia. The rupture site and intimal tear were located in the middle of the aneurysm. Open proximal and distal anastomoses were carried out using a 22 × 10 mm gelatin-covered Dacron graft. The patient was discharged from our hospital uneventfully on the 33rd postoperative day.

Citicoline and postconditioning provides neuroprotection in a rat model of ischemic spinal cord injury

BACKGROUND

Ischemic spinal cord injury is a chain of events caused by the reduction and/or cessation of spinal cord blood flow, which results in neuronal degeneration and loss. Ischemic postconditioning is defined as a series of intermittent interruptions of blood flow in the early phase of reperfusion and has been shown to reduce the infarct size in cerebral ischemia. Our study aimed to characterize the relationship between the neuronal injury-decreasing effects of citicoline and ischemic postconditioning, which were proven to be effective against the apoptotic process.

METHOD

Spinal cord ischemia was produced in rats using an intrathoracic approach to implement the synchronous arcus aorta and subclavian artery clipping method. In our study, 42 male Sprague-Dawley rats (309 +/- 27 g) were used. Animals were divided into sham operated, spinal ischemia, citicoline, postconditioning, and postconditioning citicoline groups. Postconditioning was generated by six cycles of 1 min occlusion/5 min reperfusion. A 600 mmol/kg dose of citicoline was given intraperitoneally before ischemia in the citicoline and postconditioning citicoline groups. All rats were sacrificed 96 h after reperfusion. For immunohistochemical analysis, bcl-2, caspase 3, caspase 9, and bax immune staining were performed. Caspase 3, caspase 9, bax, and bcl-2 were used as apoptotic and antiapoptotic markers, respectively.

FINDINGS

The blood pressure values obtained at the onset of reperfusion were significantly lower than the preischemic values. A difference in immunohistochemical scoring was detected between the caspase 3, caspase 9, bax, and bcl-2 groups. When comparisons between the ischemia (groups 2, 3, 4, and 5) and sham groups (group 1) were performed, a significant increase in caspase 3, caspase 9, bax, and bcl-2 was detected. When comparing the subgroups, the average score of caspase 9 was found to be significantly higher in ischemia group 2. The average score of bcl-2 was also found to be significantly higher in postconditioning and citicoline group 5.

CONCLUSIONS

It is thus thought that combining citicoline with postconditioning provides protection by inhibiting the caspase pathway and by increasing the antiapoptotic proteins.

Repair of extensive thoracoabdominal aortic aneurysm with a tetrafurcate graft: midterm results of 63 cases

OBJECTIVE

The objective is to present a method for maintaining the spinal cord blood supply and our midterm results for using a tetrafurcate graft in extensive thoracoabdominal aortic aneurysm (TAAA) repair.

METHODS

From August 2003 to October 2007, we used a tetrafurcate graft to perform repairs to TAAAs of Crawford extent II in 63 consecutive patients. The mean age of this group of patients was 39.98 +/- 10.62 years, and 46 (73%) of them were male. All of the procedures were performed under profound hypothermia with a short interval of circulatory arrest. T6 to T12 intercostal arteries were reconstructed as a "neo-intercostal artery" (N-IA) and were connected to an 8-mm sidearm of the graft to maintain the spinal cord blood supply. Visceral arteries were joined into a patch and were anastomosed to the end of the main graft. The left renal artery was anastomosed to an 8-mm sidearm or joined to the patch. The other 10-mm sidearms were anastomosed to iliac arteries.

RESULTS

With 100% follow-up, the early-mortality rate was 7.94%. The incidence of cerebral complications was 9.52%. Temporary paraplegia was observed in 2 patients, and paraparesis occurred in 1 patient. Pulmonary complication was the most common morbidity in this group (25.40%). Two patients with Marfan syndrome had N-IA artery pseudoaneurysms during follow-up. The mean survival time of this group was 50.64 +/- 2.13 months, with survival rates of 92.06% after 1 year, 88.38% after 2 years, and 86.11% after 3 years.

CONCLUSION

The N-IA may play an important role in spinal cord protection, and N-IA pseudoaneurysm should be avoided in Marfan syndrome patients. The use of a tetrafurcate graft is a reliable method for TAAA repair, with satisfactory midterm results.

Beneficial effect of the oxygen free radical scavenger amifostine (WR-2721) on spinal cord ischemia/reperfusion injury in rabbits

Background

Paraplegia is the most devastating complication of thoracic or thoraco-abdominal aortic surgery. During these operations, an ischemia-reperfusion process is inevitable and the produced radical oxygen species cause severe oxidative stress for the spinal cord. In this study we examined the influence of Amifostine, a triphosphate free oxygen scavenger, on oxidative stress of spinal cord ischemia-reperfusion in rabbits.

Methods

Eighteen male, New Zealand white rabbits were anesthetized and spinal cord ischemia was induced by temporary occlusion of the descending thoracic aorta by a coronary artery balloon catheter, advanced through the femoral artery. The animals were randomly divided in 3 groups. Group I functioned as control. In group II the descending aorta was occluded for 30 minutes and then reperfused for 75 min. In group III, 500 mg Amifostine was infused into the distal aorta during the second half-time of ischemia period. At the end of reperfusion all animals were sacrificed and spinal cord specimens were examined for superoxide radicals by an ultra sensitive fluorescent assay.

Results

Superoxide radical levels ranged, in group I between 1.52 and 1.76 (1.64 ± 0.10), in group II between 1.96 and 2.50 (2.10 ± 0.23), and in group III (amifostine) between 1.21 and 1.60 (1.40 ± 0.19) (p = 0.00), showing a decrease of 43% in the Group of Amifostine. A lipid peroxidation marker measurement ranged, in group I between 0.278 and 0.305 (0.296 ± 0.013), in group II between 0.427 and 0.497 (0.463 ± 0.025), and in group III (amifostine) between 0.343 and 0.357 (0.350 ± 0.007) (p < 0.00), showing a decrease of 38% after Amifostine administration.

Conclusion

By direct and indirect methods of measuring the oxidative stress of spinal cord after ischemia/reperfusion, it is suggested that intra-aortic Amifostine infusion during spinal cord ischemia phase, significantly attenuated the spinal cord oxidative injury in rabbits.