Supraceliac Aortic Cross-clamping Research Articles

Development of a portable abdominal normothermic regional perfusion (A-NRP) program in the United States.

In situ abdominal normothermic regional perfusion (A-NRP) has been used for liver transplantation (LT) with donation after circulatory death (DCD) liver grafts in Europe with excellent results; however, adoption of A-NRP in the United States has been lacking. The current report describes the implementation and results of a portable, self-reliant A-NRP program in the United States. Isolated abdominal in situ perfusion with an extracorporeal circuit was achieved through cannulation in the abdomen or femoral vessels and inflation of a supraceliac aortic balloon and cross-clamp. The Quantum Transport System by Spectrum was used. The decision to use livers for LT was made through an assessment of perfusate lactate (q15min). From May to November 2022, 14 A-NRP donation after circulatory death procurements were performed by our abdominal transplant team (N = 11 LT, N = 20 kidney transplants, and 1 kidney-pancreas transplant). The median A-NRP run time was 68 minutes. None of the LT recipients had post-reperfusion syndrome, nor were there any cases of primary nonfunction. All livers were functioning well at the time of maximal follow-up with zero cases of ischemic cholangiopathy. The current report describes the feasibility of a portable A-NRP program that can be used in the United States. Excellent short-term post-transplant results were achieved with both livers and kidneys procured from A-NRP.

A Supraceliac Aortic Cross Clamping Model to Explore Remote Lung Injury and the Endothelial Glycocalyx

We hypothesized that supraceliac aortic cross clamping could induce lung injury mediated by an inflammatory ischemia-reperfusion (IR) trigger. We aimed to characterize glycocalyx (GCX), a component of endothelial membrane, participating to remote lung injury. Rats underwent supraceliac aortic cross clamping for 40min and were sacrificed at 0, 3, 6, and 24hr of reperfusion (n=10/group). Each group was compared to sham (n=6/group). GCX products (syndecan-1 [Sdc-1] and heparan sulfate [HS]), tumor necrosis factor-alpha (TNF-α), and interleukin-1β (IL-1β) were measured in plasma (enzyme-linked immunosorbent assay[ELISA]). Lungs were harvested for measurements of TNF-α, IL-1β (polymerase chain reaction) and Sdc-1 (western blotting [WB]). Histologic lung injury scoring and pulmonary gravimetry were analyzed in a blinded manner. Plasmatic Sdc-1, HS, TNF-α, and IL-1β reached peak levels at 3hr. Levels were significantly higher in clamping groups than sham at 6hr for Sdc-1, at 0 and 3hr for HS, at 3 and 6hr for TNF-α, and at 3hr for IL-1β. Lung TNF-α and Interleukin-1β reached peak levels at 6hr. Levels were significantly higher than sham at 6 and 24hr for TNF-α and at 6hr for IL-1β. Lung Sdc-1 was lowest at 3hr. Sdc-1 was not significantly different compared to sham at the different reperfusion times. At 3hr, it was 0.27±0.03 vs. 0.33±0.02 (sham) (P=0.09). Histopathologic scores at 6 and 24hr were higher in clamping groups than sham. At 6 and 24hr, it was higher for hemorrhage, polynuclear neutrophil (PNN) infiltration and intravascular leukocytes. Pulmonary edema was higher by gravimetry at 0 and 6hr. Supra celiac aortic clamping causes early lung injury in relation with a systemic inflammatory response associated with altered GCX structure.

Long-term results of open surgical repair of non-infrarenal abdominal aortic aneurysms

Introduction: Solid evidence is not available on the ideal technique of surgical repair (open or endovascular) of noninfrarenal abdominal aortic aneurysms. Objective: Our aim was to analyze the postoperative effect of mortality and the level of proximal cross-clamping of the patients who underwent open surgical aortic repair of non-infrarenal abdominal aortic aneurysms with intact wall. Method: This is a retrospective, single-centre study, which reviews the results of open surgical repair, performed for intact non-infrarenal abdominal aorta aneurysms between 2005 and 2017. Aneurysms were analyzed in two groups, based on the level of aortic cross-damping: juxta-pararenal aortic aneurysm group with inter- or suprarenal aortic cross-clamping and suprarenal aortic aneurysm group with supraceliac aortic cross-clamping. Primary endpoints were 30-day, 1-, 2- and 5-year mortality. Secondary endpoints were postoperative acute kidney injury, including hemodialysis, and major postoperative complications. Results: In our clinic, 94 patients underwent open surgical aortic repair with cross-clamping above at least one renal artery. The median follow-up was 3.14 (1.55-5.00) years. The overall 30-day, 1-, 2- and 5-year mortality were 9%, 20%, 27% and 48%, respectively. The mortality was significantly lower in the juxta/pararenal abdominal aortic aneurism group at 30 day and 1 year. The overall perioperative incidence of acute kidney injury was 54% and 30% at discharge. Significantly more in-hospital acute renal dysfunction was noticed in the patients with suprarenal aortic aneurysm than with juxta/pararenal aneurysm, however, the difference was not significant at discharge. Major postoperative complications were more frequent in the suprarenal aneurysm group. Conclusion: Open surgical repair of abdominal aortic aneurysms with supraceliac aortic cross-clamping is associated with significantly higher morbidity, early and mid-term mortality than the repair of juxta/pararenal aneurysms. Chronic kidney disease and major postoperative complications are independent factors of mid- and long-term mortality.

Supraceliac aortic cross-clamping to control bleeding from the celiac axis during pancreatic surgery: a case report

BackgroundIntraoperative bleeding from the celiac axis (CA) can occur during pancreatic surgery, and appropriate management is essential to avoid critical complications. Here, we have reported a case that was managed with supraceliac aortic cross-clamping (SAC) for arterial bleeding from the CA during pancreatic surgery.Case presentationA 70-year-old man was diagnosed with pancreatic cancer located in the pancreatic head and body. Preoperative computed tomography showed a stricture at the root of the CA, which may have been caused by a median arcuate ligament. Pancreaticoduodenectomy with division of the median arcuate ligament was scheduled. Uncontrollable bleeding from the root of the CA was observed during surgery. The bleeding was controlled by performing SAC, and a defect in the CA was confirmed. Arterial wall repair was successfully performed under temporal blood control using SAC. The aortic clamp time was 2 min and 51 s, and the intraoperative blood loss was 480 ml.ConclusionsAlthough SAC is primarily a procedure for ruptured abdominal aortic aneurysm, it can be useful for the management of CA injuries during pancreatic surgery.

Real-Time Assessment of Spinal Cord Microperfusion in a Porcine Model of Ischemia/Reperfusion.

Spinal cord injury is a devastating complication of aortic repair. Despite developments for the prevention and treatment of spinal cord injury, its incidence is still considerably high and therefore, influences patient outcome. Microcirculation plays a key role in tissue perfusion and oxygen supply and is often dissociated from macrohemodynamics. Thus, direct evaluation of spinal cord microcirculation is essential for the development of microcirculation-targeted therapies and the evaluation of existing approaches in regard to spinal cord microcirculation. However, most of the methods do not provide real-time assessment of spinal cord microcirculation. The aim of this study is to describe a standardized protocol for real-time spinal cord microcirculatory evaluation using laser-Doppler needle probes directly inserted in the spinal cord. We used a porcine model of ischemia/reperfusion to induce deterioration of the spinal cord microcirculation. In addition, a fluorescent microsphere injection technique was used. Initially, animals were anesthetized and mechanically ventilated. Thereafter, laser-Doppler needle probe insertion was performed, followed by the placement of cerebrospinal fluid drainage. A median sternotomy was performed for exposure of the descending aorta to perform aortic cross-clamping. Ischemia/reperfusion was induced by supra-celiac aortic cross-clamping for a total of 48 min, followed by reperfusion and hemodynamic stabilization. Laser-Doppler Flux was performed in parallel with macrohemodynamic evaluation. In addition, automated cerebrospinal fluid drainage was used to maintain a stable cerebrospinal pressure. After completion of the protocol, animals were sacrificed, and the spinal cord was harvested for histopathological and microsphere analysis. The protocol reveals the feasibility of spinal cord microperfusion measurements using laser-Doppler probes and shows a marked decrease during ischemia as well as recovery after reperfusion. Results showed comparable behavior to fluorescent microsphere evaluation. In conclusion, this new protocol might provide a useful large animal model for future studies using real-time spinal cord microperfusion assessment in ischemia/reperfusion conditions.

Ringer's ethyl pyruvate solution attenuates hypoperfusion and renal injury after multivisceral ischemia-reperfusion in rabbits.

Ringer's ethyl pyruvate solution (REPS) has been protective against experimental renal, intestinal, and spinal ischemia and may be useful for organ protection in major vascular surgery. The purpose of this study was to investigate whether REPS attenuates organ injury in a rabbit model of supraceliac aortic cross-clamp that simulates thoracoabdominal aortic surgery. Following the Institutional Animal Care and Use Committee's approval, 20 rabbits were undergone cross-clamping of the supraceliac thoracic aorta for 30min, and observed for 180min after reperfusion. Either REPS (33mg/kg/h of ethyl pyruvate) or Ringer's lactate solution were infused throughout the study period. Arterial pressure and aortic blood flow were continuously monitored. Blood lactate concentration, serum transaminase levels, neutrophil activation, and urinary N-acetyl-beta-glucosaminidase (NAG) activity were evaluated. After reperfusion, supraceliac aortic blood flow was significantly higher, and urinary NAG was significantly lower in animals that received REPS, while the other parameters were not significantly different. In conclusion, REPS attenuated the reduction of aortic blood flow and urinary NAG elevation after the cross-clamp of supraceliac aorta.

Merits of and Technical Tips for Supra-Mesenteric Aortic Cross Clamping.

Supra-celiac aortic cross clamping is often utilized during aortic reconstruction for aneurysmal/occlusive disease involving the pararenal aorta. However, this may be accompanied a myriad of complications related to hemodynamic disturbances, cardiopulmonary compromise and hepatic ischemia. Supra-mesenteric aortic cross clamping may be an excellent option in selected patients with suitable anatomy to minimize or avoid these complications. Herein, the merits of and technical tips for supra-mesenteric aortic cross clamping are discussed.

Open repair of ruptured abdominal aortic aneurysm with associated horseshoe kidney.

Ruptured abdominal aortic aneurysms (RAAA) with concomitant horseshoe kidney (HK) present a unique challenge at the time of repair. The aim of this article was to propose the most rationale strategy during open repair (OR) of RAAA in the presence of HK. We identified and analyzed all patients treated at the clinic due to RAAA and HK. An extensive search was performed on all articles published up to August of 2017 describing open and endovascular repair of RAAA with concomitant horseshoe kidney. The following data were extracted and analyzed: patient number, number of renal arteries, Crawford classification of horseshoe kidney vascularization, type of aortic reconstruction, management with renal arteries, 30-day kidney failure and outcome. Transperitoneal approach followed by supraceliac aortic cross clamping without the division of the renal isthmus occurred in all our six cases. Four of them required additional procedures with accessory renal arteries after aortic replacement. Three of patients (50%) died during the first 30 postoperative days, while one developed transitory renal insufficiency. The renal isthmus was preserved in 43.90% and divided in 46.34% of cases. Crawford type I of HK vascularization was presented in 21.95% of cases, type II also in 39.02%, while the type III in 19.51% of cases. In 46.33% of cases a procedure with renal arteries was necessary. In 26.82% accessory renal arteries were ligated, while in 19.51% preserved (reattachment or aorto-renal bypass). Thirty-day mortality was 21.95%, while the incidence of postoperative renal failure was also 21.95%. There was not significant correlation between the renal artery ligation and the postoperative renal failure (r=-0.81, P=0.59). Transperitoneal approach should be preferred during urgent OR of RAAA with concomitant HK. A supraceliac aortic cross clamping and the placement of occlusive Fogarty catheters into both iliac arteries are recommended for proximal and distal bleeding control. Preservation of accessory renal arteries that are larger than 3 mm in diameter or supply more than 30% of renal parenchima is recommended. The division of the renal isthmus should be avoided if vascularized. It seems that renal arteries could be covered in emergency EVAR without any implications on postoperative kidney function, allowing broader aplication of endovascular treatment for thesse patients.

FT10. Open Repair of Type IV Thoracoabdominal Aortic Aneurysm: Results of Passive Visceral Shunt and Two-Graft Technique

Open repair of type IV thoracoabdominal aneurysms (TAAs) remains a surgical challenge because of the hazardous but necessary intraoperative visceral and renal ischemia. We report a novel approach with passive arterial shunt and two-graft technique to reduce these ischemic complications. A first bifurcated graft is anastomosed laterally to the distal descending thoracic aorta, before left renal artery bypass and intraoperative perfusion of both superior mesenteric and right renal arteries. A second graft is used for in-line aneurysm reconstruction. We herein present our experience of type IV TAA open repair using this technique. Twenty-four patients (mean age, 68 years) underwent elective open repair for type IV TAA with this technique between January 2011 and December 2017. The intervention was achieved through a left thoracophrenic lumbotomy, with retroperitoneal and retrorenal approach. A bifurcated graft was anastomosed laterally to the distal descending thoracic aorta to bypass the left renal artery before aortic cross-clamping. The second limb of this bifurcated graft was connected to a Y-shaped cannula to simultaneously perfuse both superior mesenteric and right renal arteries during supraceliac aortic cross-clamping (Fig 1). An additional tube or bifurcated graft was then used for in-line aneurysm reconstruction. The visceral aortic patch was anastomosed to the aortic graft with the Crawford inclusion technique. The prosthetic limb graft used as a temporary arterial shunt was ligated at the end of the intervention; the left renal artery bypass was preserved as part of the definitive arterial reconstruction (Fig 2). Patients’ records were analyzed for demographics, comorbidities, arterial lesions, operative variables, complications, and 30-day mortality. Mean left renal ischemia time was 10.5 minutes. Mean aortic cross-clamping was 31 minutes. The creatinine level at discharge was not significantly different from the preoperative level (15 vs 13; P = .01). Three patients (12.5%) had transient renal failure (Acute Kidney Injury Network stage 1) postoperatively. Prolonged ventilatory support (>2 days) was necessary in two patients (8%). No cardiac event, no dialysis, and no multivisceral organ failure have been recorded. The postoperative mortality rate was 4% (one patient). Type IV TAA repair with our passive shunt and two-graft technique provides short visceral and renal ischemia times and leads to low rates of end-organ ischemic damages. This technique could be an option to consider for visceral protection in type IV TAA open repair and spurs us on to maintain it for our future cases.Fig 2Arterial reconstruction.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Remote Ischemic Preconditioning Decreases the Magnitude of Hepatic Ischemia-Reperfusion Injury on a Swine Model of Supraceliac Aortic Cross-Clamping

Temporary hepatic ischemia is inevitable during open aortic surgery when supraceliac clamping is necessary, as in thoracoabdominal or pararenal aneurysms. Remote ischemic preconditioning (RIPC) has been described as a potential protective means against ischemia-reperfusion injury (IRI) in various tissues including the liver. The aim of this experimental study was to detect the effect of RIPC on liver IRI in a model of supraceliac aortic cross-clamping. An animal study was performed. Four groups of 6 swines each were examined: the control (sham) group, the ischemia-reperfusion (IR) group, and 2 remote ischemic preconditioning groups (RIPC I and RIPC II group). In the IR group, the animals underwent a complete cessation of the splanchnic arterial circulation for 30min by a concomitant occlusion of the supraceliac and the infrarenal aorta. In the RIPC groups, a remote preconditioning was applied before the splanchnic ischemia. This consisted of a temporary occlusion of the infrarenal aorta for 15min followed by 15min of reperfusion (RIPC I group), and 3 cycles of 5min similar ischemia, followed by 5min of reperfusion each (RIPC II group). All animals were followed for 24hr after the ischemia (reperfusion period). The liver ischemia-reperfusion injury was assessed by examining specific serum biomarkers indicating the magnitude of metabolic injury from selective blood samples of the hepatic circulation. In particular, the following parameters were examined: C-reactive protein, interleukin 6, tumor necrosis factor a, ferritin, and L-arginine. All parameters were affected in the IR group as compared to the sham group. Both RIPC groups developed a less serious change as compared to the IR group, in all examined parameters. In an animal study of splanchnic ischemia produced in a way to this produced during a supraceliac aortic aneurysm open repair, the remote ischemic preconditioning seemed to attenuate the effect of hepatic ischemia-reperfusion injury. Remote ischemic preconditioning produced with short bouts of ischemia of the lower body by temporary clamping of the infrarenal aorta might be used as a means of decreasing the detrimental effects of hepatic ischemia-reperfusion injury after supraceliac aortic cross-clamping. This was found in a swine model of suprarenal AAA open repair by studying the variance of certain biological biomarkers in selective blood samples retrieved from the hepatic vein.

A Brief Period of Hypothermia Induced by Total Liquid Ventilation Decreases End-Organ Damage and Multiorgan Failure Induced by Aortic Cross-Clamping.

In animal models, whole-body cooling reduces end-organ injury after cardiac arrest and other hypoperfusion states. The benefits of cooling in humans, however, are uncertain, possibly because detrimental effects of prolonged cooling may offset any potential benefit. Total liquid ventilation (TLV) provides both ultrafast cooling and rewarming. In previous reports, ultrafast cooling with TLV potently reduced neurological injury after experimental cardiac arrest in animals. We hypothesized that a brief period of rapid cooling and rewarming via TLV could also mitigate multiorgan failure (MOF) after ischemia-reperfusion induced by aortic cross-clamping. Anesthetized rabbits were submitted to 30 minutes of supraceliac aortic cross-clamping followed by 300 minutes of reperfusion. They were allocated either to a normothermic procedure with conventional ventilation (control group) or to hypothermic TLV (33°C) before, during, and after cross-clamping (pre-clamp, per-clamp, and post-clamp groups, respectively). In all TLV groups, hypothermia was maintained for 75 minutes and switched to a rewarming mode before resumption to conventional mechanical ventilation. End points included cardiovascular, renal, liver, and inflammatory parameters measured 300 minutes after reperfusion. In the normothermic (control) group, ischemia-reperfusion injury produced evidence of MOF including severe vasoplegia, low cardiac output, acute kidney injury, and liver failure. In the TLV group, we observed gradual improvements in cardiac output in post-clamp, per-clamp, and pre-clamp groups versus control (53 ± 8, 64 ± 12, and 90 ± 24 vs 36 ± 23 mL/min/kg after 300 minutes of reperfusion, respectively). Liver biomarker levels were also lower in pre-clamp and per-clamp groups versus control. However, acute kidney injury was prevented in pre-clamp, and to a limited extent in per-clamp groups, but not in the post-clamp group. For instance, creatinine clearance was 4.8 ± 3.1 and 0.5 ± 0.6 mL/kg/min at the end of the follow-up in pre-clamp versus control animals (P = .0004). Histological examinations of the heart, kidney, liver, and jejunum in TLV and control groups also demonstrated reduced injury with TLV. A brief period of ultrafast cooling with TLV followed by rapid rewarming attenuated biochemical and histological markers of MOF after aortic cross-clamping. Cardiovascular and liver dysfunctions were limited by a brief period of hypothermic TLV, even when started after reperfusion. Conversely, acute kidney injury was limited only when hypothermia was started before reperfusion. Further work is needed to determine the clinical significance of our results and to identify the optimal duration and timing of TLV-induced hypothermia for end-organ protection in hypoperfusion states.

The Rationale for Continuing Open Repair of Ruptured Abdominal Aortic Aneurysm

Mortality after open repair of ruptured abdominal aortic aneurysms (RAAAs) remains high. The purpose of this study is to present the results of open RAAA treatment observing 2 different 10-year periods in a single high-volume center and to consider the possibilities of result improvement in the future. Retrospective analysis of 729 RAAA patients who were treated through 1991-2001 (229 patients, Group A) and 2002-2011 (500 patients, Group B) was performed. Variables significantly associated with mortality were defined and analyzed. Overall 30-day mortality in Group A was 53.7% (123/229 patients) with intraoperative mortality of 13.5% (31/229 patients), while in Group B it was 37.4% (187/500 patients) with intraoperative mortality of 12.4% (62/500 patients). Overall 30-day mortality was significantly lower in Group B (P=0.012). There was no difference regarding intraoperative mortality (P=0.797). Preoperative severe hemodynamic instability (P<0.01, P<0.001), cardiac arrest (P<0.01, P<0.001), consciousness deterioration (P<0.05, P<0.001), renal malfunction (P<0.01, P<0.001), and significant anemia (P<0.01, P<0.001) were associated with increased mortality in both A and B groups, respectively. Aortic cross-clamping level in Group A was predominantly infrarenal (68%) while in Group B it was mostly supraceliac (53%) (P<0.001). Cross-clamping time, duration of surgery, and type of aortic reconstruction had no influence on survival in Group B (P>0.05). Intraoperative hemodynamic instability (P<0.01, P<0.001), significant bleeding (P<0.05, P<0.01), and low urine output (P<0.05, P<0.001) remained parameters that favored lethal outcome in both A and B groups, respectively. Cell saving was used only in Group B. The multivariate logistic regression applied on the complete sample of patients presented several significant predictors of lethal outcome: congestive heart failure on admission (odds ratio [OR] 1.954, 95% confidence interval [CI] 1.103-3.460), intraperitoneal rupture (OR 3.009, 95% CI 1.771-5.423), aortofemoral reconstruction (OR 1.928, 95% CI 1.044-3.563), and total operative time (OR 1.005, 95% CI 1.001-1.010). Postoperative multisystem organ failure (P<0.01, P<0.001), respiratory (P<0.01, P<0.001) and renal (P<0.05, P<0.001) failure, postoperative bleeding (P<0.05), and cerebrovascular incidents (P<0.05, P<0.01) significantly increased mortality in both A and B groups. Although unselective, aggressive surgical approach in RAAA performed by teams experienced in open repair can improve patient's survival. Short admission/surgery time, supraceliac aortic cross-clamping, and the use of intraoperative cell saving are recommended.

Comparison of supramesenteric aortic cross-clamping with supraceliac aortic cross-clamping for aortic reconstruction

Supraceliac aortic cross-clamping (SCXC) is routinely used during open aortic reconstruction (OAR) of pararenal aortic disease when suprarenal control is not feasible. On occasion, however, aortic control may be obtained at the supramesenteric level by supramesenteric cross-clamping (SMXC) between the superior mesenteric artery and the celiac axis. The purpose of this study was to compare outcomes between patients who had SMXC vs SCXC during OAR for both aneurysmal and occlusive diseases. A retrospective chart review identified 69 patients who underwent elective OAR requiring SMXC (n= 18) or SCXC (n= 51). All patients with thoracoabdominal aneurysms and those who had inframesenteric (suprarenal and infrarenal) aortic control were excluded. Propensity score-based matching was performed to adjust for confounding factors in a 1:1 ratio to compare outcomes. Late survival was estimated by Kaplan-Meier methods. Propensity score-based matching was performed at a 1:1 ratio; 18 SMXC cases were matched with 18 SCXC cases. The average age was 66.7years, and men constituted 72%. Baseline characteristics were matched, except for the incidence of peripheral vascular occlusive disease (72.2% in the SMXC group vs 33.3% in the SCXC group; P= .04). A majority (80.6%) of patients underwent OAR for aneurysmal disease (72.2% in the SMXC group, 88.9% in the SCXC group). Intraoperatively, there were no differences in operative times (325minutes for SMXC vs 298minutes for SCXC; P=.48), but the SMXC group had a longer renal ischemia time (40minutes vs 28minutes; P= .03). There were no significant differences in intraoperative blood loss (2.4L vs 1.6L; P= .2) or blood product transfusion requirements (packed red blood cells, 2.2 units vs 1.6 units [P= .5]; Cell Saver, 1.3L vs 0.7L [P= .09]). Overall complication rates did not differ significantly (27.8% for SMXC vs 44.4% for SCXC; P= .24). Thirty-day mortality rates did not differ between the two groups (0% for SMXC vs 5.6% for SCXC; P= 1). In this study, there were no differences in early morbidity or mortality between SMXC and SCXC during aortic reconstruction. SMXC, however, can be performed safely and effectively in properly selected patients. A larger, multicenter prospective study would help elucidate the potential benefits.

Remote Ischemic Preconditioning May Attenuate Renal Ischemia-Reperfusion Injury in a Porcine Model of Supraceliac Aortic Cross-Clamping

Aim: The effect of remote ischemic preconditioning (RIPC) in decreasing renal ischemia-reperfusion injury (IRI) during a suprarenal aortic cross-clamping was examined in a swine model. Materials and Methods: Four groups of pigs were examined: (a) ischemia-reperfusion (IR) group, renal IRI produced by 30 min of supraceliac aortic cross-clamping; (b) RIPC I group, the same renal IRI following RIPC by brief occlusion of the infrarenal aorta (15 min ischemia and 15 min reperfusion); (c) RIPC II group, the same renal IRI following RIPC by brief occlusion of the infrarenal aorta (3 cycles of 5 min ischemia and 5 min reperfusion); (d) sham group. Renal function was assessed before and after IRI by examining creatinine, neutrophil gelatinase-associated lipocalin (NGAL), TNF-α, malondialdehyde (MDA), cystatin C and C-reactive protein (CRP) from renal vein blood samples at specific time intervals. Results: Both RIPC groups presented significantly less impaired results compared to the IR group when considering MDA, cystatin C, CRP and creatinine. Between the two RIPC groups, RIPC II presented a better response with regard to CRP, NGAL, TNF-α, MDA and cystatin C. Conclusions: Remote IR protocols and mainly repetitive short periods of cycles of IR ameliorate the biochemical kidney effects of IRI in a model of suprarenal aortic aneurysm repair.

Preliminary Results from a National Enquiry of Infection in Abdominal Aortic Endovascular Repair (Registry of Infection in EVAR - R.I.EVAR)

To preliminary report on epidemiology, risk factors, diagnosis, treatments, and outcomes in a multicenter series of patients treated for endovascular aortic repair (EVAR) infection and detected by an Italian National enquiry. From June 2012, 26 cases of abdominal aortic endograft infection were collected by a National Enquiry and recorded in the Italian National Registry of Infection in EVAR. Cases collected were available for patients submitted to EVAR implantation from January 2004 to June 2013. Mean time from EVAR treatment to infection diagnosis was 20.5 ± 20.3 months (range, 1-72). In 6 cases (23.1%), an aortoenteric fistula (AEF) was detected. Positive microbiologic cultures were found in 20 patients (76.9%). More than 1 infectious agent was found in 6 cases (19.2%). EVAR infection treatment was conservative in 4 cases, endovascular in 2. Endograft excision was performed in 10 cases by conventional treatment (aortic stump + extra-anatomic bypass) and in 10 cases by in situ reconstruction (cryopreserved allograft or rifampin-soaked silver Dacron graft). A 30-day mortality was 38.4% (10 of 26 cases), 3 patients died from 2 to 24 months after infection treatment, accounting for a mean time from infection treatment to death of 1.25 ± 0.62 months. Mortality rates were 50% in all treatment groups. In those survived (13 of 26 cases) recurrence-free follow-up after infection treatment was 27.9 ± 22.4 months (range, 2-74). Four patients with AEF died in the first month after treatment (66.6%). Suprarenal endografts required supraceliac aortic cross-clamping for removal. Supraceliac cross-clamping was burdened by higher mortality rates than infrarenal cross-clamping (71.4% vs. 30.7%). EVAR infection diagnosis is burdened by extremely high mortality rates. Prospective registries could help monitoring outcomes in EVAR infection patients and, possibly, developing new surveillance protocols in patients at high risk of recurrence.

Liver Autotransplantation in Pigs without Venovenous Bypass: A Simplified Model using a Supraceliac Aorta Cross-Clamping Maneuver.

The pig is an essential model for liver transplantation research and training. However, it develops hemodynamic instability during the anhepatic phase, requiring a short anhepatic phase or an extracorporeal circulation not appropriate for training purposes because it increases the risk of intraoperative complications. In this article we describe an economical and reproductive experimental model for training surgeon fellows in liver transplantation, without veno-venous bypass, using a supraceliac aortic cross-clamping maneuver. After liver liberation, we cross-clamped the supraceliac aorta and cross-clamped and divided the infrahepatic inferior vena cava (IVC), bile duct (BD), hepatic artery (HA), portal vein (PV), and suprahepatic IVC. We rapidly removed and flushed the liver ex situ, repositioned it orthotopically, and performed anastomosis in suprahepatic IVC, infrahepatic IVC and PV, reperfusing the liver. Lastly, we anastomosed the HA and BD. We also performed pulmonary artery catheter exams and recovery blood samples serially before and after graft reperfusion (beginning of anesthesia = basal; 5 min after reperfusion and 120 min after reperfusion = end-point) for hemodynamic and metabolic assessment. Transplantation fellows were able to perform the operations assisted by a senior surgeon. The median procedure time was 211 min (188-233 min). One pig died due to hemorrhage and 5 remained alive for up to 2 h after liver reperfusion, achieving at this time normal hemodynamic and metabolic parameters. This model is suitable for training and experimentation, avoids venovenous bypass, is low cost, avoids immunological reaction, and prevents hemodynamic and metabolic complications.

Tranexamic acid corrects fibrinolysis in the presence of acidemia in a swine model of severe ischemic reperfusion

Tranexamic acid (TXA) is an antifibrinolytic with anti-inflammatory properties associated with improved outcomes when administered to trauma patients at risk for bleeding; however, its efficacy is unknown in acidemia. We evaluated the efficacy of TXA on hyperfibrinolysis using an established porcine traumatic hemorrhage ischemic shock model. Ten Yorkshire swine underwent a controlled hemorrhage followed by supraceliac aortic cross-clamping. During standard resuscitation, control animals received recombinant tissue plasminogen activator (rtPA) after cross-clamp removal, and experimental animals received rtPA followed by TXA. Rotational thromboelastometry analysis was performed at baseline, 5 minutes and 15 minutes after rtPA dosing, and 4 hours after cross-clamp removal. Control and experimental animals had similar hemodynamics and routine laboratory values at baseline and throughout resuscitation. At the time of TXA administration, average pH was 7.2. Clot formation time was prolonged from baseline and all resuscitation time points in both groups, with no difference at any time point. Maximum clot firmness decreased from baseline at all resuscitation time points in both groups. Maximum lysis increased from baseline (9% control vs. 9% TXA) after tissue plasminogen activator administration in both groups (100% control vs. 99% TXA). In experimental animals, maximum lysis returned to baseline 10 minutes after TXA administration (92% vs. 9%, p < 0.001). TXA rapidly and fully reverses hyperfibrinolysis despite severe acidemia in a porcine trauma model. TXA is a promising adjunct to trauma resuscitation that is easily administered in austere or prehospital settings.

Acute coagulopathy in a porcine venous hemorrhage and ischemia reperfusion model

BackgroundInjury-related coagulopathy is a complex process. We analyzed coagulation in a swine model of shock using rotational thromboelastometry (ROTEM). MethodsForty-eight swine underwent laparotomy, 35% hemorrhage, supraceliac aortic cross-clamp, then reperfusion and resuscitation. ROTEM measurements and standard labs were taken at baseline and 6 hours into resuscitation. ResultsClot formation time (98 vs 53 seconds, P = .001) and international normalized ratio (1.67 vs 1.01, P < .001) were prolonged after resuscitation. Maximum clot firmness (61 vs 72 mm, P < .001) and fibrinogen levels (94 vs 165, P < .001) declined significantly during resuscitation. Despite decreased fibrinogen levels, there was no significant increase in fibrinolysis as measured by maximum lysis (3.9% vs 3.8%, P = .99). ConclusionsROTEM demonstrated the development of an acute coagulopathy. The most significant impacts on coagulopathy were seen with clot initiation and fibrin polymerization. Clot strength decreased over time, although there was little impact on clot breakdown because of fibrinolysis.

Pharmacologic attenuation of the hyperdynamic response to supraceliac aortic clamping

Aortic occlusion is accompanied by a hyperdynamic cardiovascular response secondary to increased systemic vascular resistance and increased cardiac output. This study was designed primarily to determine the safety and cardiovascular response to hydrogen sulfide (H2S; HS) administration with supraceliac aortic cross-clamp and, secondarily, on short-duration resuscitation. A validated porcine model (five sham swine compared with five controls) demonstrated a significant hyperdynamic cardiovascular response to 35% blood volume hemorrhage, 50-minute suprarenal aortic cross-clamping, and 6-hour resuscitation. Eight additional experimental swine were administered HS at 4 mg/min during aortic cross-clamping. During the cross-clamp period, hemodynamic curves of mean arterial pressure and heart rate demonstrated a blunting effect with HS administration, with a significant decrease being seen with mean arterial pressure at the end of the cross-clamp period (120 vs 149 mm Hg; P = .04). Resuscitation requirements were significantly reduced at 6 hours because the HS cohort received 8 L less crystalloid (P = .001) and 10.4 mg less epinephrine (P < .001). There was not a significant change in cardiac output, systemic vascular resistance, pulmonary vascular resistance, or pathologic liver analysis. The administration of HS during the 50 minutes of supraceliac aortic cross-clamp significantly reduced stress of the left heart. On clamp release, HS significantly reduced the need for volume and pressors. HS has positive benefits during cross-clamp and subsequent resuscitation, demonstrating that targeted pharmacologic therapy is possible to minimize adverse physiologic changes with aortic occlusion.

Aortic Occlusion Hemodynamic Attenuation With Valproic Acid

Objectives: Valproic acid (VPA; a histone deacetylase inhibitor) has demonstrated significant decreases in resuscitation requirements as well as minimizing pathologic physiology following short term aortic occlusion. The purpose of this study was to compare the cardiac and hemodynamic changes with VPA administration following supraceliac aortic occlusion. Methods: 19 swine were exposed to a 35% blood volume hemorrhage followed by a supraceliac aortic cross clamp only model with valproic acid (400 mg/kg) administered as a drip continuously during supraceliac aortic cross clamping (CC, n 1⁄4 9). Hemodynamics were measured with the use of arterial blood pressure monitor and a pulmonary artery thermodilution catheter. Results: 10 swine were divided into two equal groupssham and model. In this validation, hemodynamics were significantly different as measured after hemorrhage and cross clamp by mean arterial pressure (MAP; P 1⁄4 .024), heart rate (P < .001), cardiac index (CI; P 1⁄4 .005). In the comparison arm of control and cross clamp group, there was a significant attenuation in the adverse hemodyamic response with administration of VPA (n 1⁄4 9) during cross clamp (MAP 1⁄4 87 6 28 vs CC-122 6 43 mm Hg; P 1⁄4 .02; HR 1⁄4 124 6 23 vs CC-161 6 32 bpm; P 1⁄4 .01). Additionally, throughout the cross clamp application, there was a significantly decreased hyperdynamic response with the administration of VPA (Fig). Conclusions: VPA helps attenuate the adverse hyperdynamic cardiac response following a hemorrhagic event and subsequent aortic occlusion. The hemodynamic response appeared to be not only significant at each time interval, but sustained as cross clamp times increased. Additionally, VPA seemed to minimize pathologic hemodynamic variation and provide cardiac protection through minimizing cardiac stress and work of the heart during aortic occlusion. Author Disclosures: M. W. Causey: Nothing to disclose; M. Martin: Nothing to disclose; S. Miller: Nothing to disclose; N. Singh: Nothing to disclose.