Temporary Shunt Research Articles

Temporary Axillorenal Bypass in Complex Aorto-Renal Surgery

Prolonged renal ischemia during vascular surgery carries high morbidity and mortality. We report an alternative technique for maintaining renal circulation during suprarenal aortic or renal artery clamping. Between October 2007 and May 2012, 16 patients undergoing aorto-renal surgery (13 men, 3 women) were operated using temporary axillorenal bypass. Operations were performed for supra- and juxtarenal aortic aneurysms (11), occlusive aortic disease (2), renal artery stenoses (2), and abdominal myofibroblastic tumor (1). In elective cases, axillorenal bypass was planned, when prolonged renal ischemia was expected based on preoperative information. Preoperative risk factors (renal dysfunction, hypertension, coronary disease, diabetes, smoking) and intraoperative variables (operating time, blood loss, renal ischemia time) were assessed and compared with postoperative kidney function (serum creatinine, urine output, dialysis) and in-hospital or 30-day-mortality. Even though renal blood flow was restored between clampings, the total cumulative ischemia time was used in analysis. Acute renal failure postoperatively was based on RIFLE criteria. Preoperatively, 44% (7) of the patients had normal renal function (S-crea ≤ 100mmol/L). Renal function was moderately present in 50% (8) (S-crea 100-200mmol/L) and severely in 6% (1) (S-crea ≥ 200mmol/L). Median operation time was 393min (251-535min) and median renal ischemia time was 24.5min (range 8-50min). Transient acute renal dysfunction occurred in 6 (38%) patients, and 4 of them had renal insufficiency preoperatively. Transient renal replacement therapy was needed in 1 (6%) patient only. In 1-month control, postoperative renal function had returned to its baseline level or improved and in-hospital or 30-day mortality was zero. Temporary axillorenal bypass is a considerable option to minimize renal ischemia time during high-risk vascular surgery.

The Challenges in Managing Pulmonary Arterial Hypertension Associated with Congenital Heart Disease.

Congenital heart disease; Eisenmenger syndrome; Pulmonary arterial hypertension.

Shear-Activated Nanoparticle Aggregates Combined With Temporary Endovascular Bypass to Treat Large Vessel Occlusion.

The goal of this study is to combine temporary endovascular bypass (TEB) with a novel shear-activated nanotherapeutic (SA-NT) that releases recombinant tissue-type plasminogen activator (r-tPA) when exposed to high levels of hemodynamic stress and to determine if this approach can be used to concentrate r-tPA at occlusion sites based on high shear stresses created by stent placement. A rabbit model of carotid vessel occlusion was used to test the hypothesis that SA-NT treatment coupled with TEB provides high recanalization rates while reducing vascular injury. We evaluated angiographic recanalization with TEB alone, intra-arterial delivery of soluble r-tPA alone, or TEB combined with 2 doses of intra-arterial infusion of either the SA-NT or soluble r-tPA. Vascular injury was compared against stent-retriever thrombectomy. Shear-targeted delivery of r-tPA using the SA-NT resulted in the highest rate of complete recanalization when compared with controls (P=0.0011). SA-NT (20 mg) had a higher likelihood of obtaining complete recanalization as compared with TEB alone (odds ratio 65.019, 95% confidence interval 1.77, >1000; P=0.0231), intra-arterial r-tPA alone (odds ratio 65.019, 95% confidence interval 1.77, >1000; P=0.0231), or TEB with soluble r-tPA (2 mg; odds ratio 18.78, 95% confidence interval 1.28, 275.05; P=0.0322). Histological analysis showed circumferential loss of endothelium restricted to the area where the TEB was deployed; however, there was significantly less vascular injury using a TEB as compared with stent-retriever procedure (odds ratio 12.97, 95% confidence interval 8.01, 21.02; P<0.0001). A novel intra-arterial, nanoparticle-based thrombolytic therapy combined with TEB achieves high rates of complete recanalization. Moreover, this approach reduces vascular trauma as compared with stent-retriever thrombectomy.

Primary stent retrieval for acute intracranial large artery occlusion due to atherosclerotic disease.

Background and PurposeThe goal of stent retriever–based thrombectomy is removal of embolic clots in patients with intracranial large artery occlusion. However, outcomes of stent retrieval may differ between acute arterial occlusions due to intracranial atherosclerotic disease (IAD) and those due to embolism. This case series describes the outcomes of stent retriever–based thrombectomy and rescue treatments in 9 patients with IAD-related occlusion.MethodsAmong patients who underwent endovascular treatment for acute intracranial large artery occlusion, those in whom stent retrieval was attempted as first-line treatment were included in this review. IAD was defined as significant fixed focal stenosis at the occlusion site, which was evident on final angiographic assessment or observed during endovascular treatment.ResultsMedian number of stent retriever passes was 2 (range, 1-3), and temporary bypass was seen in all patients. Immediate partial recanalization (arterial occlusive lesion grade 2-3) was observed in 7 patients. Immediate modified thrombolysis in cerebral infarction grade 2b-3 was seen in 6 patients, but the lesions often required rescue treatment due to reocclusion or flow insufficiency. In terms of rescue treatments, angioplasty and intra-arterial tirofiban infusion seemed to be effective.ConclusionsOur findings suggest that stent retrieval can effectively remove thrombi from stenotic lesions and achieve partial recanalization despite the tendency toward reocclusion in most patients with IAD-related occlusion. Further research into the use of rescue treatments, such as tirofiban infusion and angioplasty, is warranted.

CFD analysis of unsteady flow through conjoining Aorta and aortic isthmus.

The initial stages of fetal development require that blood oxygenation occur through the placenta rather than the non functioning lungs. As a result the fetal circulatory system develops a temporary shunt between the aorta and pulmonary artery, known as the ductus arteriosis (DA). This study utilizes CFD techniques to analyze the flow behavior in the aortic isthmus neighboring the DA. The geometry used to represent these structures is equivalent to that of a 25 week old fetus. The effect of aortic and pulmonary pressure pulse wave delay is examined for producing flow disturbances in the fetal circulatory system. This is accomplished by analyzing both axial and tangential flow fields downstream of the DA. The study demonstrates that there exist different swirl profiles that are related to the timing of pulse contributions from both the left and right ventricles.

Pediatric vascular injury: experience of a level 1 trauma center

BackgroundOur purpose was to analyze modern major vascular injury (MVI) patterns in pediatric trauma, interventions performed, and outcomes at a level 1 trauma center. Materials and methodsFrom January 2000–December 2012, all pediatric admissions (≤17 y) were reviewed. ResultsOf 1928 pediatric admissions, 103 (5.3%) sustained MVI. This cohort was 85% male, age 15 ± 3 y, 55% black, 58% penetrating, injury severity score of 23 ± 15, with a length of stay of 8 (5) days. Firearm-related injury (47%) was the most common mechanism. Location of injuries included the extremities (50.5%), abdomen/pelvis (29.1%), and chest/neck (20.4%). Operative procedures included repair/bypass (71.4%), ligation (12.4%), amputation (10.5%), or temporary shunt (2.9%). Only three injuries (2.9%) were treated endovascularly. MVI patients had a mortality rate of 19.4%, higher than the overall pediatric trauma population of 3.5% (P < 0.001). After logistic regression, independent risk factors of mortality were vascular injury to the neck (odds ratio [OR]: 6.5; confidence interval (CI): 1.1–39.3), abdomen/pelvis (OR: 16.3; CI: 3.13–80.2), and chest (OR: 49.0; CI: 3.0–794.5). ConclusionsMVI in children more commonly results from firearm-related injury. The mortality rate associated with MVI is profoundly higher than that of the overall pediatric trauma population. These findings underscore the major public health concern of firearm-related injury in children.

Long great saphenous vein grafting as temporary coronary bypass for extended left hepatectomy: report of a case.

The right gastroepiploic artery (RGEA) has been used in coronary artery bypass grafting (CABG) as an alternative graft. In particular abdominal surgeries, surgery is required to rescue the graft flow into the coronary artery. A 77-year-old male with a history of CABG using RGEA was admitted with a diagnosis of a large hepatocellular carcinoma (HCC) occupying the whole caudate lobe. Preoperative coronary angiography indicated that the graft from the right internal mammary artery to the proximal left circumflex artery was obliterated among three branch bypasses. Following laparotomy, a great saphenous vein was harvested and delivered from the right axial artery to the RGEA graft over the thoracic wall, and the RGEA graft was ligated and divided. Subsequently, extended left hepatectomy was safely performed. Following hepatectomy, the RGEA graft was restored to the former condition, and the temporary graft was removed. After overcoming hyperbilirubinemia, the patient was discharged on postoperative day 28. This experience indicates that temporary bypass using the long great saphenous vein is effective and safe during long and invasive surgeries.

NPH: are we giving up on patients with temporary improvement post shunt?

Normal pressure Hydrocephalus (NPH) is predominantly treated with a ventriculoperitoneal shunt (VPS) resulting in improvement in the Hakim triad (mobility, cognitive function, urinary continence). There are a population of patients who experience an improvement in symptoms post shunt insertion followed by a subsequent deterioration in their condition in the proceeding months / years. At our institution, a large volume (min 40ml) CSF withdrawal is made via the shunt reservoir in these patients, measuring pre/post mobility and cognitive function. Comparison is then made between pre/post results and if a clear improvement is seen, VP shunt surgical revision is offered.

Obstructive tracheal cylindroma resection using temporary local anaesthetic-instituted peripheral cardiopulmonary bypass

Obstructive tracheal cylindroma resection using temporary local anaesthetic-instituted peripheral cardiopulmonary bypass

Directly measuring spinal cord blood flow and spinal cord perfusion pressure via the collateral network: Correlations with changes in systemic blood pressure

During thoracoabdominal surgery in which segmental arteries are sacrificed over a large area, blood supply routes from collateral networks have received attention as a means of avoiding spinal cord injury. The aim of this study was to investigate spinal cord blood supply through a collateral network by directly measuring spinal cord blood flow and spinal cord perfusion pressure experimentally. In beagle dogs (n=8), the thoracoabdominal aorta and segmental arteries L1-L7 were exposed, and a temporary bypass was created for distal perfusion. Next, a laser blood flow meter was placed on the spinal dura mater in the L5 region to measure the spinal cord blood flow. The following were measured simultaneously when the direct blood supply from segmental arteries L2-L7 to the spinal cord was stopped: mean systemic blood pressure, spinal cord perfusion pressure (blood pressure within the aortic clamp site), and spinal cord blood flow supplied via the collateral network. These variables were then investigated for evidence of correlations. Positive correlations were observed between mean systemic blood pressure and spinal cord blood flow during interruption of segmental artery flow both with (r=0.844, P<.01) and without (r=0.834, P<.01) distal aortic perfusion. In addition, we observed significant correlations between spinal cord perfusion pressure and spinal cord blood flow with and without distal perfusion (r=0.803, P<.001 and r=0.832, P<.01, respectively), and between mean systemic blood pressure and spinal cord perfusion pressure with and without distal perfusion (r=0.898, P<.001 and r=0.837, P<.001, respectively). The spinal cord was perfused from the collateral network from outside the interrupted segmental arteries, and high systemic blood pressure (∼1.33-fold higher) was needed to obtain the preclamping spinal cord blood flow, whereas 1.68-fold higher systemic blood pressure was needed when distal perfusion was halted. Spinal cord blood flow is positively correlated with mean systemic blood pressure and spinal cord perfusion pressure under spinal cord ischemia caused by clamping a wide range of segmental arteries. In open and endovascular thoracic and thoracoabdominal surgery, elevating mean systemic blood pressure is a simple and effective means of increasing spinal cord blood flow, and measuring spinal cord perfusion pressure seems to be useful for monitoring perioperative spinal cord blood flow.

The experimental study and clinical application of temporary intravascular shunt on small blood vessels

Objective To investigate the feasibility of temporary intravascular shunt (TIVS) using on small blood vessels and the relation between the length of TIVS and the time of the patency,then observe clinical results of TIVS.Methods The right femoral artery transection model were established in 20 New Zealand white rabbits,which were divided into group A and B (n =10) randomly.The vascular stumps were bridged by the shunts with 2 mm in inner diameter,with the shunts in length in group A and B being 10 cm and 20 cm respectively.Regular observation was carried out after operation for the patency in shunts.The observation endpoint with the shunts completely blocked were as follows:the color of shunts turn into a dark red,no blood flow on Doppler ultrasound testing,no pulse in distal artery.The differences between two groups to reach the end of the time observed.The results on repairing radial artery with TIVS with 3 mm in inner diameter for patients of Gustilo Ⅲ C-type fractures in forearm and broken wrist reimplantation were observed.Results The diameter of the femoral artery of rabbits was 1.5-2.0 mm.After vascular bypass were established,there were pulse in the distal femoral artery and flow signal in shunts could be detected by Doppler ultrasound.With the passage of time,the shunts were gradually from bright red to dark red,distal pulse gradually weakened until it disappears,and the blood flow signal disappears eventually.The time reach observation endpoint in groups A,B were (240.00 ± 122.78) (117.00-363.00) min and(230.00 ± 109.20) (121.00-339.00) min respectively.The difference between the two was not statistically significant.There were 2 clinical cases using TIVS for radial artery,and the bypass time were 180 min and 148 min.After establishing vascular bypass,peripheral blood supply were restored,the vessels remained patency after remove the shunts,distal limbs postoperative were survived.Conclusion Temporary vascular bypass could use for small blood vessels with caliber 1.5-2.0 mm,and the time to maintain through the blood was up to 4 hours.The difference in maintaining patency time using the shunts in length of 10 cm and 20 cm was no significant.Using TIVS in small vessel for replantation of broken wrist could early reconstructed distal blood supply,and reduced limb ischemia time. Key words: Temporary intravascular shunt; Extremity vascular injury ; Open fracture ; Rabbit ; Vascular bypass

NEUROMONITORINGO METODŲ VERTĖ ATLIEKANT ENDARTEREKTOMIJŲ OPERACIJAS

Žurnalas „Sveikatos mokslai / Health sciences“ yra recenzuojamas tarptautinis mokslinis žurnalas, skirtas skleisti naujas žinias ir informaciją apie visuomenės sveikatą, sveikatos ugdymą, ligas, klinikinius tyrimus ir klinikinius atvejus, naujas technologijas, slaugą, reabilitaciją, sveikatos ekonomiką ir vadybą. Žurnalas spausdina mokslinius straipsnius lietuvių, anglų ir rusų kalbomis, kasmet išeina 1 tomas (6 numeriai) spausdintiniu ir elektroniniu variantais. Daugiau nei 140 mokslinių straipsnių publikuojami per metus. Žurnalas priklauso Lietuvos mokslo periodikos asociacijai.

Successful living donor liver transplantation for giant extensive venous malformation

We report our success in employing LDLT as a course of treatment for extensive hepatic VM. A 14-yr-old pediatric patient presented at our hospital with nosebleed, fatigability, orthopnea, and abdominal distension. He had a history of right hemicolectomy with primary anastomosis due to VM of the transverse colon at age seven. Coagulation abnormalities were apparent, characterized by high international normalized ratio of prothrombin time, decreased fibrinogen level, increased FDPs, and D-dimer. T2-weighted magnetic resonance imaging revealed numerous, variable-sized high signal intensity nodules. Abdominal ultrasonography and CT scan showed hepatomegaly with multiple hypo-echogenic lesions and arteriovenous shunting in the liver. Doppler ultrasound showed hypokinetic flow in the hypo-echogenic lesions of liver. Immediate LDLT was performed to avoid spontaneous rupture and DIC. The right lobe of the liver was implanted with temporary portocaval shunt to prevent intestinal congestion and bleeding. Pathologic examination of the explanted liver confirmed the presence of an extensive hepatic VM. The postoperative course was uneventful, and the patient remained symptom-free with normal liver function throughout the 12-month follow-up period.

Transpopliteal stenting of femoral occlusions in patients with critical limb ischemia using a 4-French system.

In many patients with critical limb ischemia (CLI), transfemoral endovascular recanalization is the preferred treatment. Transpopliteal treatment may be used in patients with inaccessible groins. This retrospective study regards transpopliteal stenting of superficial femoral artery (SFA) occlusions using a 4F system. Eleven patients (4 male and 7 female [mean age 77years]) underwent 12 attempts of transpopliteal recanalization of long SFA occlusions (Trans-Atlantic InterSociety Consensus B through D). All patients had CLI (Rutherford 4 to 6) and were nonoperable due to poor general condition. Indications for transpopliteal access were proximal/flush SFA occlusions (n=5), failure of antegrade recanalization (n=4), infected femoral-femoral crossover bypass (n=2), and occlusion of both the native SFA and the femoral-popliteal bypass (n=1). The popliteal artery was punctured under ultrasound guidance. Occlusions were recanalized subintimally, and 4F compatible stents were implanted. Technical success rate (<30% residual stenosis) was achieved in 83% of cases. In two patients, stent dislocation occurred while the sheath was removed. One arteriovenous fistula was successfully treated with additional stenting. During 6-month follow-up, there were no major amputations, and three patients died from nonrelated causes. Fifty percent of patients alive after 6months improved to Rutherford score ≤3. The duplex restenosis (>50%) rate at 6months was 50%. Transpopliteal primary stenting of complex SFA lesions in CLI for a temporary bypass is now technically feasible using a 4F system. Technical results are promising. Clinical results after 6months are acceptable when taking into consideration that this approach may be the last option for limb salvage.

Application of Temporary Vascular Shunting by Infusion Rubber Tubing for Salvage of the Major Vessel Injuries in Limbs

Application of Temporary Vascular Shunting by Infusion Rubber Tubing for Salvage of the Major Vessel Injuries in Limbs

Damage control strategies in the management of acute injury.

Traumatic injury is the leading cause of death worldwide. The rapid evaluation and correction of injuries in these patients is paramount to preventing uncontrolled decompensation and death. Damage control strategies are a compendium of techniques refined over decades of surgical care that focus on the rapid correction of deranged physiology, control of contamination and blood loss, and resuscitation of critical patients. Damage control resuscitation (DCR) focuses on the replacement of lost blood volume in a manner mimicking whole blood, control of crystalloid administration, and permissive hypotension. Damage control laparotomy controls gastrointestinal contamination and bleeding in the operative suite, allowing rapid egress to the intensive care unit for ongoing resuscitation. Pelvic packing, an adjunct to DCR, provides a means to control hemorrhage from severe pelvic fractures. Temporary vascular shunts restore perfusion, while resuscitation and reconstruction are ongoing. Taken together, these strategies provide the trauma surgeon with a powerful arsenal to preserve life in the transition from injury to the shock trauma room to the intensive care unit.

Spontaneous intrahepatic portocaval shunt in a patient undergoing liver transplantation

We recently observed a single large intrahepatic portocaval hunt (IPS) in a patient with significant encephalopathy underoing liver transplantation. Pre-transplant computed tomography can showed a large IPS connecting the right portal vein to the etrohepatic vena cava (Fig. 1). Patient was transplanted followng the piggy-back technique with temporary portocaval shunt. epatectomy initially followed a standard right-side approach to he left side resulting in shunt laceration with profuse bleeding. nce haemostasis was obtained the surgical strategy was changed nd the hepatectomy was carried out from left-side to the right llowing lateral clamping of the inferior vena cava thus makng it easier to suture the shunt and minimizing blood loss [1]. PS is a rare venous malformation characterized by diversion of ortal blood flow away from the liver into the systemic circulaion. It may be congenital (Abernethy malformation) or acquired, n adults mostly associated with cirrhosis and portal hypertenion or hepatic trauma. This malformation is extremely rare in on-cirrhotic patients where it has been reported associated with patent ductus venosus. In case of portal hypertension IPS is mall and diffusely located in the cirrhotic liver, but a single nd large IPS that diverges a large amount of portal flow into he systemic circulation is extremely rare. Preoperative recogition of IPS and a left-to-right approach are essential in liver ransplantation.

Carotid Bypass: A Safe and Durable Solution for Recurrent Carotid Stenosis

The long-term results of carotid artery stenting (CAS) for post-carotid endarterectomy (CEA) restenosis are disappointing (4-year patency rates: ∼75%). Since 1988, our group has offered carotid bypass (CB) as an alternative to redo CEA and later also to CAS in this setting. The aim of this retrospective study was to investigate early and late outcomes associated with CB in this population. Data were collected from patients treated with CB in the year 2000-2012 for significant/symptomatic post-CEA restenosis (or intra-stent restenosis [ISR] after CAS for post-CEA restenosis). All patients had good life expectancy. CB was performed under loco-regional anesthesia. With the aid of sequential vessel clamping, the graft (great saphenous vein [GSV] or polytetrafluoroethylene) was anastomosed with the common carotid artery (side-to-end) and the distal internal carotid artery (end-to-side). Patients were followed with clinical and duplex scan assessments at 1, 3, and 6 months and yearly thereafter. The study population comprised 21 patients (mean age 67.3 years; 17 men). CB was performed for post-CEA restenosis (or ISR after CAS for post-CEA restenosis, n=3) 51.2 months (mean) after the previous operation. GSV grafts were used in half of the cases (n=11; 52.4%); temporary shunting was used in 4 (19%) patients. Intraoperative complications (none fatal) occurred in 4 (19%) patients (3 transient peripheral nerve injuries, 1 cervical hematoma). During follow-up (mean 64.8 months), there were no neurologic complications or restenoses. Overall mortality was 33.3% (6 deaths from acute myocardial infarctions, 1 from a ruptured abdominal aortic aneurysm). For post-CEA restenosis (or ISR after CAS for post-CEA restenosis), CB offers superior long-term patency rates than CAS (or redo angioplasty) and an acceptable risk of cranial nerve damage.

Damage control surgery after severe superior mesenteric artery injury

Objective To determine the effect of different surgical modalities on hemodynamics,systemic major organ injury and survival rate following superior mesenteric artery (SMA) injury in an attempt to search a modality that conforms to principles of damage control surgery (DCS).Methods SMA was exposed in 30 domestic hybrid pigs,leaving the blood flow blocked using non-invasive vessel forceps.The animals were divided into control group,primary anastomosis group (anastomosis group) and temporary intravascular shunt (TIVS) group according to random number table.TIVS group was further divided into three subgroups:shunting for 6 hours group (TIVS-6 h group),9 hours group (TIVS-9 h group) and 12 hours group (TIVS-12 h group).At each time point,the angiography was performed for evaluation of shunt patency; hemodynamic parameters were detected,terminal ileum and SMA samples were harvested for pathological analysis.Results All groups suffered extreme physiological conditions including hypothermia,severe acidosis,hypotension,low cardiac output and low oxygen supply.Less requirement of resuscitation fluid,faster restoration of SMA blood flow,earlier clearance of lactate,milder intestinal ischemia-reperfusion injury and higher survival rate were observed in TIVS-6 h and TIVS-9 h groups,compared with anastomosis group.Patency rate in TIVS-6 h,9 h and 12 h groups was 100％,50％ and 0％ respectively.Pathologic outcome of intestine revealed diffuse intestinal necrosis in TIVS-12 h group and reversible intestinal ischemia-reperfusion injury in TIVS-6 h and 9 h groups.Conclusion For SMA injury in severe hemodynamic disarrangement and jeopardized condition,TIVS shortens intestinal ischemia time,maintains systemic hemodynamic stability,relieves intestinal injury,improves early survival rate and keeps long-term intestine patency when compared with primary vascular anastomosis. Key words: Shock; Mesenteric artery, superior; Damage control surgery

Liver Transplantation Using Low-Weight Recipients From a Graft Split Program

We present our experience with a split liver (SL) program shared with the children's liver transplantation (LT) program from 2 different hospitals in the use of partial grafts from cadaver donors in brain death. We describe an observational, retrospective study, which included patients who underwent a SL transplantation in our center between January 2006 and December 2012. Clinical variables were recorded of both donors and recipients and their data were analyzed using SPSS 19.0 software. Of a total of 204 LT, 4 (2%) patients were treated with a SL. The causes of LT were alcoholic cirrhosis in 2 cases, cryptogenic cirrhosis, and primary biliary cirrhosis (PBC). In all cases there was a temporary portocaval shunt. The confluence of the hepatic veins of the recipient was anastomosed to the donor vena cava and arterial anastomosis was performed. The reconstruction was hepato-choledochal in all cases. There were no cases of postreperfusion syndrome or vascular thrombosis and no retransplantation was necessary. Currently, 3 of the 4 cases are still alive. Death in the other patient was due to mesenteric ischemia. Our center has participated in the development of a protocol that considers the indication of this technique provided expert groups are involved in its development, regardless of hospital level. This will expand the pool of donors and partially solve the current problems with available grafting.