Infrarenal Aortic Clamping Research Articles

Acceptable Intra-aortic Balloon Occlusion Duration Affecting the Regional Saturation Oxygen of Lower Limbs Using Near-infrared Spectroscopy for Abnormally Adherent Placentation

Objective: To investigate the utility of regional saturation oxygen (rSO2) using near-infrared spectroscopy (NIRS) in the lower limbs and to estimate the safe occlusion duration in patients with abnormally adherent placentation who underwent intra-aortic balloon occlusion (IABO) during a cesarean hysterectomy by comparing them with infrarenal aortic clamping. Methods: The researchers classified 15 lower limbs of patients with abnormally adherent placentation with IABO during a cesarean hysterectomy as the balloon group and 20 lower limbs of patients with cross-clamping on the infrarenal aorta during the aneurysmal repair as the clamping group. The rSO2 measurement of the limbs was performed using a near-infrared spectrometer. In addition, the aortic occlusion duration, rSO2 before and during occlusion, and after blood resumption were analyzed. Results: Continuous rSO2 measurement was possible in all patients. The median aortic occlusion durations in the balloon and clamping groups were 68 and 92.5 min, and the median minimum rSO2 during occlusion was 60% and 17.5%, respectively. The clamping group was found to have stronger occlusion for a longer time than the balloon group. No complications associated with aortic occlusion were observed in both groups. Conclusions: rSO2 measurement using a near-infrared spectrometer effectively monitors lower-limb blood flow during IABO in patients with abnormally adherent placentation. An IABO duration of approximately 90 min was believed to be relatively acceptable in a cesarean hysterectomy under heparin administration.

Dexmedetomidine attenuates pneumocyte apoptosis and inflammation induced by aortic ischemia-reperfusion injury

ABSTRACT Objective Despite significant improvements in interventional vascular aneurysm repair procedures and intensive care patient management, there has been no significant decrease in mortality due to ruptured abdominal aortic aneurysm. Oxidative stress is known to play a key role in secondary organ damage due to infrarenal aortic clamping. The aim of this study was to examine the potential protective effect of the alpha-2 adrenergic receptor agonist dexmedetomidine (DMT) on aortic occlusion-induced lung injury. Methods Thirty Sprague Dawley rats were allocated into control, ischemia-reperfusion (IR), and IR+DMT groups randomly. Vascular clamps were attached to the abdominal aorta in the IR and IR+DMT groups. Two-hour reperfusion was established 1 h after ischemia. The IR+DMT group received a single intraperitoneal 100 µg dose of DMT 30 min before infrarenal abdominal aortic clamping. Results IR due to aortic occlusion led to apoptosis, widespread inflammation, alveolar septal wall thickening due to bleeding and vascular congestion were observed in both types I and II pneumocytes. Malondialdehyde levels increased while glutathione decreased. However, DMT was found to lower apoptotic pneumocytes, alveolar-septal thickness, hemorrhage, vascular congestion, and malondialdehyde levels, while glutathione levels in lung tissue increased. Conclusions This study is the first to address the effects of DMT on the lung in a ruptured abdominal aortic aneurysm model. Our findings suggest that the alpha-2 adrenergic receptor agonist DMT reduces oxidative stress and apoptosis, thus protecting against aortic occlusion-induced pulmonary injury.

Effects of remifentanil and propofol on distant organ lung injury in an ischemia-reperfusion model.

Our aim was to evaluate lung injury due to oxidative stress and antioxidant activity levels in an infrarenal ischemia–reperfusion model and to compare prevention effects of single and combined use of propofol and remifentanil. In this study, a total of 40 adult Wistar Albino rats were randomly divided into five groups of eight rats as SHAM, physiological saline, intraperitoneal propofol, remifentanil, and propofol and remifentanil groups. Blood and tissue samples were obtained after 80 min of reperfusion. The malondialdehyde (MDA) level, a measure of lipid peroxidation, was measured in lung tissue samples and red blood cells; additionally, total oxidant status and total antioxidant capacity of lung tissues were measured and histopathological examination was performed. Distant organ (lung) injury developed due to lower extremity ischemia–reperfusion was created by infrarenal aortic clamping. The lipid peroxidation product MDA and total oxidant levels were increased, but there was insufficient antioxidant protection both in the lung tissues and red blood cells. While propofol prevented this injury consistent with its proposed antioxidant properties; no protective effect of remifentanil was observed. On the contrary, it showed oxidative stress increasing effect. This study concluded that the antioxidant effect of propofol was suppressed by remifentanil in the case of combined use.

The effect of fucoidin on kidney and lung injury in a rat infrarenal aortic ischemia-reperfusion model.

The aim of this study was to investigate the effects of fucoidin on rat kidney and lung in an infraaortic ishemia reperfusion model. Forty Wistar rats were randomly divided into five groups (n = 8) as sham, control (IR), before ischemia (BI), before reperfusion (BR), and before ischemia and before reperfusion (BI/BR). Rats were subjected to 120 minutes ischemia followed by 120 minutes reperfusion with application of infrarenal aortic clamping. BI received intravenous fucoidin (25 mg/kg) ten minutes before establishing ischemia and BR received ten minutes before reperfusion. BI/BR group received half equal doses of fucoidin both before ischemia (12.5 mg/kg) and reperfusion (12.5 mg/kg) periods, respectively. After sacrification blood and tissue samples were obtained for biochemical (Malondialdehyde (MDA), Nitric oxide (NO), Myeloperoxidase (MPO), Catalase (CAT), Plasma Chitotriosidase (CHIT) and serum ischemia modified albumin (IMA)) and histologic examinations. MDA, NO, MPO, CAT, and IMA levels were lower in BR and BI/BR groups compared to control group (p < 0.001). Plasma CHIT levels in BR and BI/BR groups were lower than in control group (p < 0.05). According to histological examination kidney and lung injury scores were lower in BR and BI/BR groups compared to control group (p < 0.01 and p < 0.001, respectively). The study showed that fucoidin is effective in preventing kidney and lung injury if administered before reperfusion or both before ischemia and reperfusion. However, it has no effect if administered only before ischemia.

The Impact of Suprarenal Cross-Clamping on Kidney Function in Patients Undergoing Retroperitoneal Abdominal Aortic Aneurysm Repair following an Enhanced Recovery Protocol

The retroperitoneal approach (RP) is a well-established procedure for juxtarenal and infrarenal (IR) abdominal aortic aneurysm (AAA) repair when an endovascular option is not available. The aim of this study is to compare the effect of suprarenal (SR) and IR aortic clamping on postoperative renal function following an Enhanced Recovery Protocol (ERP). Since there are no defined guidelines within aortic surgery, we focused our attention on the role of fluid and vasopressor administration in the development of postoperative acute kidney injury (AKI). This is a single-center retrospective cohort study on 140 RP aortic aneurysm repair patients operated between 2009 and 2019. Patients were divided in 2 groups: 24 had SR clamping and 116 IR clamping. Since 2009, at our institution all patients have followed an Enchanced Recovery Program which has been implemented as standard care for patients undergoing open AAA repair. The 2 groups were well matched for baseline characteristics, preoperative renal function, and comorbidity. There was an increased need for intraoperative fluids (P=0.015), and vasopressors (P=0.002) in the SR group compared to the IR group. Patients in the SR group showed a higher trend of postoperative AKI as opposed to the control group (37.5% vs. 19.8%), although this event was not statistically significant (P=0.106). Acute Kidney Injury Network stage III requiring temporary dialysis occurred in only 3 patients who all belonged to the IR group. Conversely, stage I and II with a 2- or 3-fold increase in postoperative creatinine were more frequent in the SR group. However, these normalized before discharge in all cases. To the best of our knowledge, none of the above required permanent dialysis. The results from this study show that SR clamping during RP juxtarenal aortic aneurysm repair does not have an adverse effect on postoperative renal function in the short term. However, patients undergoing SR clamping require greater fluid and vasopressor usage, in contrast with the restrictive fluid therapy established by traditional protocols. This could be an important benchmark for future implementation of ERPs in vascular surgery, especially in open procedures requiring visceral clamping.

The Influence of Suprarenal Aortic Cross-clamping on Perioperative and Follow-up Results of Open Repair of Abdominal Aortic Aneurysm

The objective was to retrospectively assess the perioperative and long-term outcomes in patients operated on with open repair of abdominal aortic aneurysm (AAA) with or without suprarenal aortic cross-clamping in a single-center experience. From January 2008 to December 2018, 1608 consecutive open and endovascular interventions for AAA were performed. Data concerning these interventions were prospectively recorded; a retrospective analysis of the database was performed and 540 elective open interventions for unruptured AAA were found, in 73 cases with suprarenal aortic cross-clamping (group 1) and in 467 cases with infrarenal aortic cross-clamping (group 2). The two groups were compared in terms of clinical, anatomic, and surgical characteristics and perioperative (<30 days) outcomes with χ2 test; follow-up results were compared with Kaplan-Meier curves and log-rank test. There were no differences between the two groups in terms of demographics, risk factors, and comorbidities, except for a higher percentage of female patients in group 1 than in group 2 (16.2% and 9.1%, respectively; P = .05). Mean preoperative estimated glomerular filtration rate was similar in the two groups as well. Most patients in both groups had a bifurcated aortobi-iliac graft; in group 1, 22 patients had a unilateral or bilateral renal revascularization, whereas in 51 cases, the ostium of one or both renal arteries was included in the proximal anastomosis. The mean time of renal ischemia in group 1 was 16 ± 12 minutes. Patients in group 1 had a longer time of intensive care unit stay than patients in group 2, but the overall length of stay was similar. Perioperative mortality rates were 4.1% in group 1 and 2.7% in group 2 (P = .5); nonfatal major complications occurred in 14 patients in group 1 (19%) and in 69 patients in group 2 (14.5%; P = .3). Follow-up was available in 512 patients (95%), with a median duration of 48 months (range, 1-144 months). Estimated 7-year survival rates were 51.5% in group 1 and 76.5% in group 2 (P < .001; log-rank, 15.3), whereas the corresponding figures in terms of freedom from AAA-related complications were 63.5% and 85.5% (P = .002; log-rank, 9.5). Moreover, patients in group 1 were more likely than patients in group 2 to undergo a reintervention at 7-year follow-up. In patients with complex AAA requiring suprarenal aortic cross-clamping, a significant increase of long term mortality, AAA-related complications, and reintervention was found in comparison with patients undergoing infrarenal aortic clamping.

The efficacy of adalimumab on experimentally induced spinal cord ischemia-reperfusion injury

Objective: Paraplegia is a dangerous complication of thoracoabdominal aortic surgery. Various studies have been conducted on the prevention of this complication and some spinal cord protection methods have been proposed. However, there is not any modality that prevent the development of paraplegia certainly. In the I / R period, primary injury triggers secondary injury due to increased inflammation, apoptosis and free radical formation. In this study, we evaluated that the neuroprotective effect of adalimumab in spinal cord ischemia-reperfusion injury. &#x0D; Materials and Methods: In total, 24 adult New Zealand rabbits were divided into three groups: Group 1, control; Group 2, ischemia-reperfusion by infrarenal aortic clamping; Group 3, adalimumab treated followed by ischemia. Tissue and plasma tumor necrosis factor alpha, interleukin 6, interleukin 10, thiobarbituric acid reactive substance, total oxidant status and total antioxidant status levels were analyzed as a marker of inflammation and oxidation. Histopathological evaluation of the tissues was performed, and apoptosis was evaluated by TUNNEL method.&#x0D; Results: I/R injury significantly increases plasma and spinal cord tissue at TNF alpha, TOS, TBARS, IL6 levels and reduces plasma and spinal cord tissue to TAS and IL10 levels. Adalimumab treatment significantly reduces plasma and spinal cord tissue to TNF alpha, TOS, TBARS, IL6 and increases plasma and tissue to TAS and IL10 levels.&#x0D; Conclusion: Adalimumab treatment significantly reduces the spinal cord neuronal damage score and the number of apoptotic cells. This paper aims to demonstrate the important neuroprotective effects of adalimumab on rabbit spinal cord I/R injury.

Twenty-two Year Multicentre Experience of Late Open Conversions after Endovascular Abdominal Aneurysm Repair

The aim was to report indications, technical aspects, and outcomes of a multicentre experience of late open conversions (LOCs) after endovascular abdominal aneurysm repair (EVAR), in order to identify risk factors which may influence early morbidity and mortality rates, and long term survival. Ten vascular centres retrospectively reviewed all patients requiring LOC (≥30 days from initial EVAR, undergoing total or partial endograft explantation) from 1996 to 2017. Baseline characteristics, endograft data, indications, procedural details, post-operative outcomes, and follow up data were reviewed and analysed. Included patients totalled 232 (90.1% males, mean age 74.3±7.9 years). The number of LOC per year significantly increased during the study period, reaching 22 in 2017 (correlation r=0.867, p<.0001). Reasons for LOC were 80.2% endoleak (186/232), 15.5% endograft infection (36/232), and 9.9% endograft thrombosis (23/232). Sixty-nine patients (29.7%) were operated on urgently; rupture was present in 18.5% (43/232). Eighty-nine patients (38.4%) underwent endovascular re-interventions prior to LOC. The proximal aortic cross clamp site was infrarenal in 40.5% (94/232), suprarenal in 25.4% (59/232), supracoeliac in 32.8% (76/232), and thoracic in 1.3% (3/232). Endograft explantation was total in 164/232 patients (70.7%), and partial in the remaining 68/232 (29.3%). The overall 30 day mortality was 11.2% (26/232). Early mortality was significantly higher for patients operated on urgently (26.1% vs. 4.9%, p<.001). Suprarenal clamping (odds ratio (OR) 2.34, 95% CI 1.12-4.88) and pre-existing renal insufficiency (OR 2.11, 95% CI 1.03-4.31) were independent risk factors for post-operative renal failure on multivariable analysis. Median follow up was 24.1 months (IQR 4.4-60.6). The estimated overall one and five year survival rates were 79.7% and 58.6%, respectively. Survival estimates were significantly lower for patients with endograft infection (83.8% vs. 59% at one year, 65.2% vs. 28.9% at five years; log rank p=.005), as well as for urgent patients (87.2% vs. 62.1% at one year, 65.1% vs. 43.7% at five years; log rank p<.0001). The annual number of LOC increased over time. LOCs performed urgently or for endograft infection are associated with poor survival. Infrarenal aortic clamping has lower post-operative complication rates.

Cold Renal Perfusion During Simulation of Juxtarenal Aortic Aneurysm Repair Reduces Systemic Oxidative Stress and Sigmoid Damage in Rats

Juxtarenal aortic surgery induces renal ischaemia reperfusion, which contributes to systemic inflammatory tissue injury and remote organ damage. Renal cooling during suprarenal cross clamping has been shown to reduce renal damage. It is hypothesised that renal cooling during suprarenal cross clamping also has systemic effects and could decrease damage to other organs, like the sigmoid colon. Open juxtarenal aortic aneurysm repair was simulated in 28 male Wistar rats with suprarenal cross clamping for 45 min, followed by 20 min of infrarenal aortic clamping. Four groups were created: sham, no, warm (37 °C saline), and cold (4 °C saline) renal perfusion during suprarenal cross clamping. Primary outcomes were renal damage and sigmoid damage. To assess renal damage, procedure completion serum creatinine rises were measured. Peri-operative microcirculatory flow ratios were determined in the sigmoid using laser Doppler flux. Semi-quantitative immunofluorescence microscopy was used to measure alterations in systemic inflammation parameters, including reactive oxygen species (ROS) production in circulating leukocytes and leukocyte infiltration in the sigmoid. Sigmoid damage was assessed using digestive enzyme (intestinal fatty acid binding protein - I-FABP) leakage, a marker of intestinal integrity. Suprarenal cross clamping caused deterioration of all systemic parameters. Only cold renal perfusion protected against serum creatinine rise: 0.45 mg/dL without renal perfusion, 0.33 mg/dL, and 0.14 mg/dL (p = .009) with warm and cold perfusion, respectively. Microcirculation in the sigmoid was attenuated with warm (p = .002) and cold renal perfusion (p = .002). A smaller increase of ROS production (p = .034) was seen only after cold perfusion, while leukocyte infiltration in the sigmoid colon decreased after warm (p = .006) and cold perfusion (p = .018). Finally, digestive enzyme leakage increased more without (1.5AU) than with warm (1.3AU; p = .007) and cold renal perfusion (1.2AU; p = .002). Renal ischaemia/reperfusion injury after suprarenal cross clamping decreased microcirculatory flow, increased systemic ROS production, leukocyte infiltration, and I-FABP leakage in the sigmoid colon. Cold renal perfusion was superior to warm perfusion and reduced renal damage and had beneficial systemic effects, reducing sigmoid damage in this experimental study.

Cold Renal Perfusion During Simulation of Juxtarenal Aortic Aneurysm Repair Reduces Systemic Oxidative Stress and Sigmoid Damage in Rats

Juxtarenal aortic surgery induces renal ischaemia reperfusion, which contributes to systemic inflammatory tissue injury and remote organ damage. Renal cooling during suprarenal cross clamping has been shown to reduce renal damage. It is hypothesised that renal cooling during suprarenal cross clamping also has systemic effects and could decrease damage to other organs, like the sigmoid colon. Open juxtarenal aortic aneurysm repair was simulated in 28 male Wistar rats with suprarenal cross clamping for 45min, followed by 20min of infrarenal aortic clamping. Four groups were created: sham, no, warm (37°C saline), and cold (4°C saline) renal perfusion during suprarenal cross clamping. Primary outcomes were renal damage and sigmoid damage. To assess renal damage, procedure completion serum creatinine rises were measured. Peri-operative microcirculatory flow ratios were determined in the sigmoid using laser Doppler flux. Semi-quantitative immunofluorescence microscopy was used to measure alterations in systemic inflammation parameters, including reactive oxygen species (ROS) production in circulating leukocytes and leukocyte infiltration in the sigmoid. Sigmoid damage was assessed using digestive enzyme (intestinal fatty acid binding protein - I-FABP) leakage, a marker of intestinal integrity. Suprarenal cross clamping caused deterioration of all systemic parameters. Only cold renal perfusion protected against serum creatinine rise: 0.45mg/dL without renal perfusion, 0.33mg/dL, and 0.14mg/dL (p=.009) with warm and cold perfusion, respectively. Microcirculation in the sigmoid was attenuated with warm (p=.002) and cold renal perfusion (p=.002). A smaller increase of ROS production (p=.034) was seen only after cold perfusion, while leukocyte infiltration in the sigmoid colon decreased after warm (p=.006) and cold perfusion (p=.018). Finally, digestive enzyme leakage increased more without (1.5AU) than with warm (1.3AU; p=.007) and cold renal perfusion (1.2AU; p=.002). Renal ischaemia/reperfusion injury after suprarenal cross clamping decreased microcirculatory flow, increased systemic ROS production, leukocyte infiltration, and I-FABP leakage in the sigmoid colon. Cold renal perfusion was superior to warm perfusion and reduced renal damage and had beneficial systemic effects, reducing sigmoid damage in this experimental study.

Shenfuqiangxin Capsule inhibits apoptosis through mitogen-activated protein kinase signal pathway in rats with cardio-renal syndrome induced by infrarenal aortic-clamping

OBJECTIVETo investigate the effect of Shenfuqiangxin capsule and the underlying mechanism on cardio-renal syndrome (CRS) in rats induced by infrarenal aortic-clamping after renal ischaemia. METHODSMale Wistar rats underwent infrarenal aortic-clamping after renal ischaemia or sham operation. The surviving CRS rats were divided randomly into three groups: CRS group (CRS + 10 mL · kg−1 · d−1 pure water by gavage), SFQX group (CRS +13.2 g crude drug · kg−1 · d−1 Shenfuqiangxin by gavage), and handle region peptide (HRP) group (CRS + 10mg/kg HRP by vein). Sham operation rats were given 10 mL · kg−1 · d−1 pure water. Treatments were given 8 weeks after surgery, which lasted for 4 weeks. The rats were detected for heart structure and function by transthoracic echocardiography. PPR mRNA was detected by Reverse Transcription Polymerase Chain Reaction (RT-PCR). To determine whether the mitogen-activated protein kinase (MAPK) signal pathway is included in the heart and kidney protective function of Shenfuqiangxin capsule, MAPK related proteins such as posophorylated C-Jun amino terminal kinase (p-JNK), posophorylated extracellular signal-regulated kinase ½ (p-ERK1/2), posophorylated p38 (p-p38) were examined by Western Blot. Apoptosis in heart and kidney tissues were detected by dUTP Nick End Labeling staining. RESULTSShenfuqiangxin capsule alleviated myocardial apoptosis and inhibited PRR mRNA expression and p-JNK, p-ERK1/2, p-p38 proteins expression in CRS rats. CONCLUSIONAll the results suggest that Shenfuqiangxin capsule improves the injured heart and kidney function maybe through inhibition of MAPK response pathway.

Reproducible Arterial Denudation Injury by Infrarenal Abdominal Aortic Clamping in a Murine Model.

Percutaneous vascular interventions uniformly result in arterial denudation injuries that subsequently lead to thrombosis and restenosis. These complications can be attributed to impairments in re-endothelialization within the wound margins. Yet, the cellular and molecular mechanisms of re-endothelialization remain to be defined. While several animal models to study re-endothelialization after arterial denudation are available, few are performed in the mouse because of surgical limitations. This undermines the opportunity to exploit transgenic mouse lines and investigate the contribution of specific genes to the process of re-endothelialization. Here, we present a step-by-step protocol for creating a highly reproducible murine model of arterial denudation injury in the infrarenal abdominal aorta using external vascular clamping. Immunocytochemical staining of injured aortas for fibrinogen and β-catenin demonstrate the exposure of a pro-thrombotic surface and the border of intact endothelium, respectively. The method presented here has the advantages of speed, excellent overall survival rate, and relative technical ease, creating a uniquely practical tool for imposing arterial denudation injury in transgenic mouse models. Using this method, investigators may elucidate the mechanisms of re-endothelialization under normal or pathological conditions.

Controlled reperfusion reduces hemorheological alterations in a porcine infrarenal aortic-clamping ischemia-reperfusion model.

Restoration of blood flow after prolonged acute ischemia causes further injury to tissues. The role of increased oxidative stress is emphasized in the pathogenesis, and impairment of hemorheological factors may also hinder proper microcirculation. Controlled reperfusion at lowered pressure with diluted blood may help to decrease reperfusion injury. Four-hour infrarenal aortic clamping was performed in 16 Yorkshire pigs. In 8 animals blood flow was restored subsequently (full reperfusion, FR), in the other 8 animals clamping was followed by an initial 30 minutes of controlled reperfusion (CR) at 60 mmHg pressure with a 1 : 1 ratio mixture of blood and reperfusion solution. Blood samples were taken before the intervention, at the end of ischemia, 15 minutes, 60 minutes, 1 day and 1 week after the start of reperfusion. Hemorheological parameters were measured. Hematocrit, plasma and whole blood viscosity decreased significantly during CR, these attenuated at 1 day. At 1 week whole blood and plasma viscosities were elevated in the FR group. Erythrocyte deformability did not change significantly at any measurements. Erythrocyte aggregation decreased during CR but not in FR, and was found elevated in both groups at 1 week. Our results suggest slightly improved hemorheological properties in case of controlled reperfusion compared to full reperfusion, which may help to reduce tissue damage.

Investigation of the effect of safranal and crocin pre-treatment on hepatic injury induced by infrarenal aortic occlusion.

Ischemia-reperfusion (IR) injury of the liver is an unresolved problem that occurs during certain surgical approaches, including hepatic, cardiac and aortic operations. In this study we aimed to investigate whether crocin and safranal had protective effects on liver IR injury induced in an infrarenal aortic clamping (IRAC) model. Male Wistar-Albino rats (n=32) were divided into four groups with 8 animals each as follows: Sham, IR, IR+crocin, and IR+safranal. The infrarenal aorta (IRA) was clamped for 60min for the ischemic period and allowed to reperfuse for 120min. Blood and tissue samples were collected for biochemical, histological and immunohistological analysis. Plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were found to be significantly higher in the IR group than the sham group (respectively; p=0.015, p<0.001). There were significant differences between the IR group and the IR+crocin group or the IR+safranal group in AST levels (respectively; p=0.02, p<0.001). ALT showed a significant decrease in the IR+crocin group compared to the IR group (p<0.05). We also observed histopathological changes among the groups. Bax and Caspase-3 expression in the IR group was remarkably higher than in the other groups. Caspase-3 and Bax expression in the IR+crocin and the IR+safranal groups were significantly lower than in the IR group. Nevertheless, there were no significant differences in BCL2 expression among the groups. IRAC is a cause of IR injury in the liver. This study showed that crocin and safranal have protective effects on IR induced liver injury.

A Successful Repair of a Giant Abdominal Aortic Aneurism.

Dear Editor, We report a case of 15.4 cm abdominal aorta aneurysm, which underwent an emergent open repair. Our patient is a 64-year-old female, with past medical history of Type 2 di- abetes, hypertension and hyperlipidemia who presented to the emergency department with a two-day history of constant progressively worsening abdominal pain. Phys- ical exam was remarkable for a distended abdomen with pulsatile tender mass in the right peri-umbilical region. CT abdomen and pelvis with contrast showed a fusiform tortuous abdominal aortic aneurysm immedi- ately distal to the renal artery ostia at the level of the L1 vertebrae measuring 1.8 cm with extension into the bilat- eral common iliac arteries at the level of the bifurcation with sparing of the celiac and SMA (Figure 1). The patient was relatively healthy, but had stopped her hypertensive medications for the last year due to monetary issues and had no cardiac workup upon admission. The patient's transesophageal echocardiography (TEE) showed LVEF of 60% - 65%, PASP 35 - 40 mmHg, mild MR and TR with no wall motion abnormalities. Cardiology was consulted for risk stratification where she was declared to be low risk for a high-risk procedure. Patient was observed overnight in the intensive care unit and surgery was planned for the following morning. In the operating room, standard ASA monitors were applied. A left axillary arterial line for invasive monitor- ing of blood pressure and a right internal jugular cordis was inserted under local anesthesia. Gentle anesthetic in- duction was achieved with intravenous propofol, fentanyl and rocuronium. Tracheal intubation was uneventful with tight control of systolic blood pressure, as there was a high risk of rupture due to size. Baseline echocardiography exam was obtained via TEE. Estimated EF was 50% - 55%. ACT's were monitored throughout the procedure. Open surgical repair was carried out with a midline incision in three stages using a Hemashield bifurcated il- iac graft. The third and fourth portions of the duodenum were contiguous with the aneurysm. Firstly, after systemic heparinization the external iliac arteries were clamped fol- lowed by infra-renal aortic clamping, dissection and evac- uation of thrombus with end-to-end anastomosis of the graft to the infra-renal aorta. A clamp was applied to the graft itself followed by slow release of aortic clamp to ver- ify suture line haemostasis. The second and third stages of repair involved clamping the internal iliac arteries, dissec- tion and end-to-end anastomosis the graft to distal com- mon iliac arteries. Fluid was restricted prior to cross clamping. As in- traoperative hypotension has been associated with post-

Supraceliac Aortic Clamping for Repair of Ruptured Abdominal Aortic Aneurysm in Patients with Short Aortic Neck Length

Objective: Prompt bleeding control with proximal aortic clamping and subsequent aortic repair are very important for ruptured abdominal aortic aneurysm. However, unsuitable anatomy, such as short aortic neck length, not only disturbs the means to an expeditious repair, but may also increase morbidity and mortality. In the present study, we aimed to evaluate the efficacy of supraceliac aortic clamping for improving surgical outcomes for patients with ruptured abdominal aortic aneurysm, who have a short aortic neck length. Method: Between April 2010 and September 2015, eighteen patients underwent emergent open surgical repair of ruptured abdominal aortic aneurysm. Eight patients with a short aortic neck length underwent supraceliac aortic clamping, and 10 underwent infrarenal aortic clamping. Results: The mean supraceliac aortic clamping time was 30 ± 7 minutes. There was 1 operative death in the infrarenal aortic clamping group due to respiratory failure, and the overall operative mortality was 6%. There were no significant differences between the 2 groups with respect to postoperative complication rates or mortality. Furthermore, there were no significant differences in variables of renal function between the 2 groups, through-out the study period. Conclusion: Supraceliac aortic clamping was associated with minimal mortality and morbidity, but not with harmful effects on postoperative renal function. Thus, supraceliac aortic clamping can be safely applied for ruptured abdominal aortic aneurysm with short aortic neck length.

Erythropoietin preconditioning improves clinical and histologic outcome in an acute spinal cord ischemia and reperfusion rabbit model

This study examined effects and functional outcome of recombinant human erythropoietin (rhEPO) and carbamylated erythropoietin fusion protein (cEPO-FC) preconditioning in a rabbit model for spinal cord ischemia and resulting paraplegia. This model was chosen because only a small surgical effect is needed to cause paraplegia in rabbits, which facilitates postoperative observation of animals. Anesthetized but spontaneously breathing New Zealand White rabbits randomly received cEPO-FC (50μg/kg; n= 8), rhEPO (5000 IU/kg; n= 10), or vehicle (control; n= 10) 30minutes before and after infrarenal aortic clamping. Ideal clamping time of 22minutes was identified from preceding clamping tests (15-25minutes). Postoperative observation time was 96hours. Spinal cord function was assessed by neurologic evaluation of hind limb motor function every 12hours using a modified Tarlov score. Spinal cord tissue damage was evaluated after 96hours using hematoxylin and eosin, elastica van Gieson, Nissl, Masson-Goldner, and hemosiderin staining. Plasma levels of cell senescence markers stathmin, chitinase 1/3, elongation factor 1-α were determined. Rabbits that received rhEPO showed significant improvement of spontaneous lower limb movements until 36hours of reperfusion and improved histologic scores upon examination of the lumbar spinal cord compared with the control group. In contrast, cEPO-FC treatment showed comparable outcome to the control group concerning movements of the lower limbs and histology. Senescence markers were elevated in the control group, but not in the treatment groups, except for chitinase 3 in the rhEPO group. Only stathmin showed no significant effect. Markers for senescence might increase after acute ischemic injury. Attenuation of senescence markers might not come alone from improvement of the spinal cord. Preconditioning with rhEPO attenuates ischemia/reperfusion injury of the spinal cord, whereas the carbamylated derivative (cEPO-FC) showed no positive effect on spinal cord function.

The effects of n-acetylcysteine and desferoxamine on IL-6, TNF-a, and oxLDL after infrarenal aortic clamping

Treatment of abdominal aortic aneurysms remains a challenging task. We examined the effects of n-acetylcysteine and desferoxamine on interleukin-6, tumour necrosis factor-a, and oxidized low density lipoprotein after infrarenal aortic clamping. Fifteen piglets were assigned to three groups. The control group (Group C) received saline as placebo (10-mL dilution, bolus), whereas the Group of n-acetylcysteine (Group NAC) received 150mg/kg IV n-acetylcysteine 30 min prior to aortic clamping and 50mg/kg/h after its release (reperfusion). The desferoxamine group (Group D) received IM 100mg/kg/d desferoxamine for 3 days prior to the experiment. Interleukin-6 increased significantly one hour after aortic clamping, while administration of desferoxamine and n-acetylcysteine had no effect on its production. Tumour necrosis factor-a increased after aortic clamping and failed to normalise during the experiment in all groups. At 2 hours post-reperfusion, desferoxamine had a modest effect on tumour necrosis factor-a values, while in Group NAC, tumour necrosis factor-a had decreased by 50% at 10 min post-reperfusion. Oxidized low density lipoprotein in Group C did not increase significantly from baselines values. In Groups D and NAC, oxidized low density lipoprotein had increased at 10 min post-reperfusion, after which it progressively decreased until 2 hours post-reperfusion. Interleukin-6 and tumour necrosis factor-a increased significantly after aortic clamping. Administration of desferoxamine and n-acetylcysteine had no effect on interleukin-6, while administration of n-acetylcysteine reduced tumour necrosis factor-a by 50% at 10 min post-reperfusion. Although in Groups D and NAC oxidized low density lipoprotein increased post-reperfusion, it progressively decreased with time.

Paraplegia prevention by oral pretreatment with memantine in a rabbit model

To evaluate the role of memantine (N-methyl-d-aspartate receptor antagonist) pretreatment for the prevention of spinal cord ischemia after infrarenal aortic clamping in a rabbit model. Thirty New Zealand White rabbits were divided into 5 different groups of 6 rabbits. Groups 60-7 and 60-5 received oral memantine 60 mg once a day for 7 and 5 days, respectively, and groups 30-5 and 30-3 received oral memantine 30 mg once a day for 5 and 3 days, respectively, all before surgery. Group C (control) received normal feeds without memantine. A paraplegic model was created by clamping both the aorta and the inferior vena cava infrarenally and just proximal to their bifurcations for 45 minutes. The modified Tarlov score, motor evoked potential (MEP), serum memantine concentration, and histopathology of the spinal cord were evaluated. The mean modified Tarlov scores were 4.2±1.3, 4.3±1.0, 4.2±1.3, 4.3±1.2, and 0.8±1.6 in groups 60-7, 60-5, 30-5, 30-3, and C, respectively at 6, 24, 48, and 72 hours (P<.009 for individual groups vs control). Percentage amplitude loss of MEP by the end of surgery was 29.5%±46.3%, 11.9%±28.0%, 30.0%±46.8%, 16.7%±40.8%, and 81.8%±40.3% for the 5 groups, respectively (P=.049). After declamping, MEP reappeared in 83%, 100%, 83%, 83%, and 33% of cases in the 5 groups, respectively (P=.073). The serum memantine level was similar in the 4 memantine groups. Spinal cords were normal in most of the rabbits in groups 60-7, 60-5, 30-5, and 30-3, but severely ischemic in most of the rabbits in group C (P=.041). Oral memantine pretreatment is protective against spinal cord ischemia, and can be an additional strategy for the prevention of paraplegia during thoracoabdominal aortic surgeries.

Abstract 488: Remote Ischemic Preconditioning Attenuates Renal Ischemia-Reperfusion Injury in a Model of Thoracoabdominal Aortic Aneurysm Open Repair

Introduction: Temporary renal ischemia consists a significant factor that increases morbidity and mortality after thoracoabdominal aortic aneurysm (TAAA) open repair. Various measures have been described to protect against renal ischemia-reperfusion (IR) injury. Remote ischemic preconditioning (RIPC) has been considered a means of decreasing IR injury in various tissues. Aim of the study was to identify the effect of RIPC in reducing renal IR injury in an animal model of TAAA open repair. Material and methods: An animal based experimental study was designed. Twenty male swine were divided in 4 groups: Sham (control) group, IR group, RIPC I group, RIPC II group. Animals underwent a 30 minutes visceral ischemia after a concomitant subphrenic and infrarenal aortic clamping (IR group). In RIPC groups, two types of 15 minutes of lower body brief ischemia followed by 15 minutes of reperfusion, preceded the visceral ischemia (15 minutes ischemia and 15 minutes reperfusion in RIPC I group, and 3 cycles of 5 minutes ischemia followed by 5 minutes of reperfusion in RIPC II group). Elective renal vein blood was retrieved from the renal vein in specific time intervals of reperfusion, ranging from 30 minutes to 24 hours post-ischemia. Using ELISA techniques, serum was examined for various parameters indicating IR injury (MDA), inflammation and renal tissue damage (CRP, TNFa, Troponin I), as well as renal function (Urea, Creatinine, Cystatin C, NGAL). Results: All examined parameters were found to be less impaired in animals of RIPC groups compared to IR group, at a significant statistical level. Discussion: Blood data demonstrate a beneficial effect in reducing IR renal injury induced in a way similar to the one during a TAAA open repair, when RIPC has been preceded the IR injury.