Temporary Shunt Research Articles

The Comparison of Outcome between Thromboaspiration and Aggressive Mechanical Clot Disruption in Treating Hyperacute Stroke Patients

Stroke is the third leading cause of death in the Republic of Korea. Time is the most important factor in hyperacute stroke. Yet, there had been no protocol for mechanical thrombolysis. We have treated patients with hyperacute stroke by mechanical thrombolysis for 3 years. In current study, we analyzed the outcome of mechanical thrombolysis. From March 2008 to February 2011, 36 patients were treated with mechanical thrombolysis. Initially we treated the patients by aggressive mechanical clot disruption (AMCD) who were admitted within 6 hours after the symptom onset. If revascularization was not achieved, balloon angioplasty was performed, followed by stenting or temporary endovascular bypass was performed. The result in 15 cases was not so successful. Since then, we started using the thromboaspiration method as the first line treatment of the mechanical thrombolysis. After using the thromboaspiration, we had better results in recanalization rate, modified Rankin Score (mRS) and reperfusion injury compared to AMCD. The recanalization rate was 80.85%, mRS is 2.85, and there was only 0.09% hemorrhagic formation. Even though thromboaspiration is not statistically significant due to the limited numbers of patients enrolled in this study, we think it is a good way in mechanical thronbolysis for hyperacute stroke.

Experimentally modified Fontan circulation in an adolescent pig model without the use of cardiopulmonary bypass

SummaryBackgroundThe feasibility and the hemodynamic outcome of Fontan circulation, without the use of cardiopulmonary bypass, were studied on a beating heart of an adolescent pig model, using a modified total cavopulmonary connection.Material/MethodsEight open-chest anesthetized pigs underwent a successful total cavopulmonary connection with the use of an appropriate Y-shaped Dacron-type conduit. Through a median sternotomy, the distal part of the superior vena cava was anastomosed end-to-end to one side of the conduit. The other side of the graft was anastomosed end-to-side to the main pulmonary artery. The conduit was tailored to an appropriate length and anastomosed end-to-end to the inferior vena cava. The hemodynamic status of the animals was recorded before and after the establishment of the total cavopulmonary connection.ResultsForty-five minutes after completion of total cavopulmonary connection, and for a total of 1 hour, hemodynamic measurements showed a decrease in mean arterial and mean pulmonary artery pressures, heart rate and cardiac output. The inferior vena caval pressure and total pulmonary vascular resistance were increased.ConclusionsA total cavopulmonary connection, performed on a beating heart, without extracorporeal circulation or other means of temporary bypass, although it is technically demanding, is feasible.

Venoatrial Shunt-Assisted Cavopulmonary Anastomosis

The bidirectional Glenn shunt operation is conventionally performed under cardiopulmonary bypass. Between June 2007 and September 2009, 218 consecutive patients underwent off-pump bidirectional Glenn shunt institution for single ventricle with pulmonary stenosis complex. Their mean age was 4.72 ± 1.80 years (range, 4 months to 6 years) and median weight was 10.12 kg (range, 4.1-19 kg). A temporary shunt was created between the innominate vein and the right atrium, with a 3-way connector for de-airing. Fifty-five patients had bilateral cavae. The mean internal jugular venous pressure on clamping the superior vena cava was 24.69 ± 1.81 mm Hg. Continuous end-tidal CO₂ and O₂ saturation were monitored. Adequate oxygen saturation and blood pressure were maintained by optimizing inotropics, volume, and inspired oxygen. The mean duration of ventilation was 10.17 ± 8.96 h (range, 1-73 h). There were no gross neurological complications. Postoperative pleural effusion developed in 6 (2.75%) patients, and 4 (1.83%) had nodal rhythm. Four (1.83%) patients died in the immediate postoperative period due to low cardiac output syndrome. Venoatrial shunt-assisted bidirectional Glenn shunt surgery can be performed safely by optimizing intraoperative management strategies. It is economical and avoids the deleterious effects cardiopulmonary bypass.

A Case of Abdominal Aortic Aneurysm Associated With L-Shaped Crossed-Fused Renal Ectopia

Genitourinary anomalies are a tremendous challenge for the vascular surgeon, especially when dealing with an abdominal aortic aneurysm. We report a case of crossed-fused renal ectopia, a rare anomaly accompanied by abdominal aortic aneurysm. Bilateral renal arteries and one aberrant artery from the right common iliac artery supply the ectopic kidney. Because renal ischemia during aortic reconstruction can be a serious problem, we reconstructed a temporary right axillo-left renal artery bypass graft first, then reimplanted the aberrant renal artery. When choosing the procedure for renal preservation, preoperative multidetector-row computed tomography was useful to plan the operative strategy.

Abdominal Aortic Aneurysm Surgery in Renal, Cardiac and Hepatic Transplant Recipients

With advancements in transplantation and improved long-term allograft survival, the once rare clinical scenario of an abdominal aortic aneurysm (AAA) in a patient with a functioning allograft has become much more frequent. In transplant recipients, AAA repair has the potential to cause irreversible ischaemic injury to the transplanted organ. Different case series and case reports have mentioned a variety of techniques to offer protection to the transplanted organs during aneurysm repair such as cold perfusion, shunting, temporary surgical bypass and extracorporeal circuits etc. Critical review of these adjuncts seems to suggest that that they do not give any better results than just using a “clamp and go” approach. Endovascular aneurysm repair (EVAR) may offer some advantages for transplant patients who have suitable anatomy for endovascular stent deployment. In addition to these surgical techniques, various aspects of medical management for renal, cardiac and hepatic transplant recipients undergoing AAA repair are discussed.

Is hypothermia a reliable adjunct for spinal cord protection in descending and thoracoabdominal aortic repair with regional or systemic cooling?

1multidisciplinary approaches have been directed toward minimizing spinal cord ischemic injury during surgery of the descending thoracic and thoracoabdominal aorta. The principal modality has been distal aortic perfusion during the aortic crossclamping, which was passive in the past with a temporary shunt tube or bypass and that currently has been active with a left heart bypass or a cardiopulmonary bypass (CPB). Other approaches include the following: intraoperative monitoring of spinal cord ischemia with somatosensory evoked potentials and transcranial motor evoked potentials; reattaching the responsible intercostal artery; increasing collateral fl ow by controlling the back-bleeding of the patent intercostal arteries with high cardiac output and arterial pressures with cerebrospinal fl uid (CSF) drainage; increasing ischemic tolerance with pharmacological adjuncts including naloxane, steroid, barbiturates, and with hypothermia; reducing excitotocixity from neuronal ischemia with hypothermia, naloxane, and steroid; and attenuating reperfusion injury with steroid, hypothermia, and free radical scavengers. Particularly, in Japan, with recent great advances in diagnostic imaging modalities, preoperative demonstration of the arteria radicularis magna (Adamkiewicz artery) by magnetic resonance imaging (MRI) or computed tomography (CT) scans has been highlighted as a reliable guide for reattachment or preservation of the responsible intercostal arteries including the collaterals. Since the 1950s hypothermia has been proven effective for protecting organs, including the central nervous system, in the cardiovascular surgical fi eld. 2–5 When focusing on milestones of aortic surgery, systemic profound hypothermia at 12°–15°C was applied to aortic arch surgery for brain protection in 1975. 6

Temporary extracorporeal jugulosaphenous bypass for the peri-operative management of patients with superior vena caval obstruction: a report of three cases

Temporary extracorporeal jugulosaphenous bypass for the peri-operative management of patients with superior vena caval obstruction: a report of three cases

Intrathoracic migration of ventriculoperitoneal shunt

Sir, Intrathoracic migration of the distal end of the ventriculoperitoneal shunt is extremely uncommon. We came across this rare complication, managed successfully by thoracocentesis and shunt revision. A nine-mo-old child underwent a right side ventriculoperitoneal shunt for tuberculous meningitis with hydrocephalus. Routine X-ray post surgery revealed the distal shunt tip below the dome of diaphragm. Three mo after discharge the child presented to the casualty with severe respiratory distress. X- ray chest revealed hydrothorax with coiled distal end of the tube in the thorax with no part below the diaphragm suggesting a supradiaphragmatic intrathoracic migration of the shunt (Fig. 1). Emergency pleural tap was done to relieve the respiratory distress Once the child’s clinical condition was stabilized, revision of the distal end done. Very few cases of intrathoracic migration of the distal end of the shunt presenting with symptomatic hydrothorax. 1-5 Infants are more prone to become symptomatic, as in infants and young children less than 5 yr, the pleura cannot absorb significant cerebrospinal fluid. The intrathoracic migration of the shunt can be either supradiaphragmatic or transdiaphragmatic. 6 In supradiaphragmatic migration the site of entry into the chest is probably incorrect subcutaneous passage. Doh et al, reported incorrect subcutaneous passage under ribs confirmed by CT scan in a case of supradiaphragmatic migration of the shunt. 2 The intrathoracic migration in the present case is supradiaphragmatic as the chest X- ray revealed whole of the shunt tube coiled in the chest with no part below the diaphragm which could be possibly due to the accidental passage into pleural cavity either by passage under the ribs or in the supraclavicular fossa during tunneling. Management requires revision of the lower end with repositioning the distal end back into the peritoneal cavity is required once the patient’s clinical condition stabilizes as was done in the present case. Temporary exteriorization may be required in very sick children. Meeker et al reported a case of intrathoracic migration of the shunt in a female presenting with dyspnea in her early pregnancy which was managed by serial thoracocentesis as a temporary measure and shunt revision after delivery. 5

Cognitive Temporary Bypassing for Reliable Multi-Hop Transmission in Wireless Ad Hoc Networks

Multi-hop wireless ad hoc networks suffer from temporary link error due to fading. In order to improve packet transmission reliability and achieve efficient transmission in fading environment, a new cognitive temporary bypassing scheme is proposed based on a cross-layer approach and cognitive behavior of local nodes. The proposed scheme enables neighboring nodes to prepare and create a temporary bypass for lost-packets. This is done by monitoring message packets that include information of the multi-hop route and link-acknowledgement. The scheme also includes an anti-collision function that is necessary to prevent contention among multiple bypassing nodes. Packet success probability with the proposed scheme is studied both by theoretical analysis and time-domain computer simulation for Rayleigh faded single- and multi-hop links. Network simulation using a modified QualNet simulator validate that packet success probability is remarkably improved with the scheme for maximum Doppler frequencies up to 30Hz.

Two-Stage Liver Transplantation with Temporary Porto-Middle Hepatic Vein Shunt

Two-stage liver transplantation (LT) has been reported for cases of fulminant liver failure that can lead to toxic hepatic syndrome, or massive hemorrhages resulting in uncontrollable bleeding. Technically, the first stage of the procedure consists of a total hepatectomy with preservation of the recipient's inferior vena cava (IVC), followed by the creation of a temporary end-to-side porto-caval shunt (TPCS). The second stage consists of removing the TPCS and implanting a liver graft when one becomes available. We report a case of a two-stage total hepatectomy and LT in which a temporary end-to-end anastomosis between the portal vein and the middle hepatic vein (TPMHV) was performed as an alternative to the classic end-to-end TPCS. The creation of a TPMHV proved technically feasible and showed some advantages compared to the standard TPCS. In cases in which a two-stage LT with side-to-side caval reconstruction is utilized, TPMHV can be considered as a safe and effective alternative to standard TPCS.

Veno-venous shunt-assisted cavopulmonary anastomosis

Objective:The bidirectional Glenn shunt is commonly performed under cardiopulmonary bypass for conditions that lead to a single ventricle repair. We report our experience of bidirectional Glenn shunt done without cardiopulmonary bypass.Methods:Between June 2007 and May 2009, 186 consecutive patients underwent off-pump bidirectional Glenn shunt for a variety of complex cyanotic congenital heart defects. Age ranged from four months to six years and the median weight was 11.17 kg (range 4.3 - 18). After systemic heparinization, the procedure was done by creating a temporary shunt between the innominate vein and the right atrium connected across a three way connector for de-airing. Fifty one patients had bilateral cavae. All cases underwent complete clinical neurological examination.Results:No case required conversion onto cardiopulmonary bypass. Four patients (2.14%) died in the immediate postoperative period. The mean internal jugular venous pressure on clamping the decompressed superior vena cava was 24.69 ± 1.81 mm Hg. There was no intra-operative hemodynamic instability and oxygen saturation was maintained at more than 70% throughout. Post Glenn shunt, the saturations improved to mid 80s. Seventy four cases had documented forward flow across the pulmonary valve. The mean duration of ventilation was 10.17 ± 8.96 hours and there were no neurological complications. Six patients (3.22%) developed pleural effusions, 4 patients (2.15%) had nodal rhythm and 9 patients (4.83%) had superficial sternal wound infection.Conclusions:Our results show that off-pump bidirectional Glenn shunt can be done safely in patients not requiring associated intra-cardiac correction. It avoids cardiopulmonary bypass and its related complications, is economical and associated with excellent results. In our opinion, this is the largest series of off-pump bidirectional Glenn shunt in the literature.

Temporary extracorporeal jugulosaphenous bypass for the peri‐operative management of patients with superior vena caval obstruction: a report of three cases

Superior vena caval obstruction from a mediastinal mass presents a significant risk to patients requiring general anaesthesia, with reports of sudden death on induction of anaesthesia, during intubation and on initiation of positive pressure ventilation. We describe the first reported use of temporary extracorporeal jugulosaphenous bypass in three cases of superior vena caval obstruction and extrinsic tracheal compression caused by massive retrosternal multinodular goitre. The bypass was performed before induction of general anaesthesia with consequent reduction in upper body venous pressure and avoidance of complications.

Comparisons of Three Surgical Procedures on Intestine Ischemia Reperfusion Injury in a Superior Mesenteric Artery Injury Model

Temporary ligation, primary anastomosis, and temporary shunt have been reported to deal with superior mesenteric artery (SMA) injuries. We aimed to investigate which brought minimal ischemia reperfusion injury in a hypothermic traumatic shock swine model. SMA was completely clamped while pigs were hemorrhaged to a mean arterial pressure (MAP) of 40 mm Hg. Animals were then randomized into temporary ligation (A, n=8), primary anastomosis (B, n=8), temporary shunt (C, n=8), and control groups (n=4). Animals in group A remained SMA interrupted for additional 1h while the other groups underwent the corresponding procedures immediately. Intestine injury was assessed by histologic examination and measurement of lipid peroxidations at the end of ischemia and experiment. Overall mortality rate was 50%, 25%, and 0% in groups A, B, and C, respectively (P<0.05). The total intestine ischemia time was predominantly shorter in group C in the other groups. Remarkable elevations of malonaldehyde (MDA) in small intestine were noted after reperfusion in group A. Animals in other groups, however, did not exacerbate during the 6-h reperfusion (resuscitation period). Group C showed the lowest MDA level at the end of experiment. Myeloperoxidase (MPO) levels showed no significant elevations during the ischemia or early reperfusion period; nevertheless, it reached approximately 3- to 6-fold in groups A and B (compared with baseline, P<0.01), and remained unchanged in group C at the end of experiment. Our study suggests that temporary shunt insertion might be preferred as it shortens ischemia time, alleviates intestinal ischemia/reperfusion injury, and thus decreases early mortality in this animal model.

Temporary intravascular shunting improves survival in a hypothermic traumatic shock swine model with superior mesenteric artery injuries

Repairs of superior mesenteric artery (SMA) injuries are difficult and often result in high mortality. Our group has employed temporary intravascular shunts (TIVS) as a damage control procedure in a SMA transection model and hypothesized that TIVS would improve survival when compared with primary vascular anastomosis in the setting of a damage control surgery. The SMA was clamped and completely transected while pigs were hemorrhaged to a mean arterial pressure of 40 mmHg and maintained in shock for 30 minutes. Cold lactated Ringer's solution was gradually infused while the abdomen was open to induce hypothermia. Animals were randomized to control (no resuscitation), primary anastomosis (PA), or temporary shunting (TS) of the SMA. Animals were resuscitated for 6 hours with the shed blood and lactated Ringer's solution. Delayed anastomosis was performed in TS animals after resuscitation. Surviving animals were humanely killed 2 days after operation. Systemic hemodynamic parameters were recorded hourly. The ileum was harvested at the end of resuscitation and experiment for pathologic evaluation. All animals suffered extreme physiologic conditions: hypothermia, severe acidosis, hypotension, and depressed cardiac output and oxygen delivery. Control animals suffered 100% mortality. Compared with the PA group, TS animals required less resuscitation fluid, retained higher SMA flow rates, normalized lactate levels faster, suffered less severe intestine histopathology, and had greater early survival. Damage control surgery in the setting of SMA transection seems better managed with TS than with PA. Further validation of this model is required before generalization to human applications.

Effect of temporary shunting on extremity vascular injury: An outcome analysis from the Global War on Terror vascular injury initiative

Extremity vascular injury during the current war has been defined by anecdotal description and case series. These reports focused on estimation of short-term limb viability and technical description of commonly used adjuncts. Temporary vascular shunting (TVS) has been advocated in current care structures, yet mostly due to war environments, broader statistical scrutiny is lacking. This study's purpose is to provide perspective on TVS's impact on limb salvage, and estimate longer-term freedom from amputation. Data from the Joint Theater Trauma Registry (JTTR), Balad Vascular Registry (BVR), Walter Reed Vascular Registry (WRVR), electronic medical records, and patient interviews were collected on American Troops sustaining extremity vascular injury from June 2003 through December 2007. Those in whom arterial TVS utilization was identified comprise the TVS group. These were compared with controls with similar injury date and anatomic location managed without TVS. Descriptive statistics were employed establishing overall univariate predictors of amputation and comparison between groups. Proportional-hazards modeling, with propensity score adjustment for systemic injury severity and Level 2 care, characterized risk factors of limb loss and effect of TVS. Freedom from amputation was estimated using Kaplan Meier log-rank methods. Cases and controls consisted of 64 and 61 extremity arterial injuries, respectively. Mean follow-up was 22 months (range: 1-54 months). The TVS group was more severely injured (mean injury severity score [ISS]: 18 [SD = 10] TVS vs. 15 [SD = 10] control, P = .05) and more likely to receive Level 2 care (TVS: 26%; control: 10%, P = .02). Overall, a total of 26 amputations occurred (21%). Penetrating blasts, compared with gunshot wounds, were associated with amputation (30% vs. 6%, P = .002). After propensity score adjustment, use of TVS suggested a reduced risk of amputation (relative risk [RR] = 0.47; 95% confidence interval [CI] [0.18-1.19]; P = .11). Venous repair was associated with limb salvage (RR = 0.2; 95% CI [0.04-0.99], P = .05). Associated fracture (RR = 5.0; 95% CI [1.45-17.28], P = .01), and elevated mangled extremity severity score (MESS) ([MESS 5-7] RR = 3.5, 95% CI [0.97-12.36], P = .06; [MESS 8-12] RR = 16.4; 95% CI (3.79-70.79), P < .001) predicted amputation. Amputation-free survival was 78% in the TVS group and 77% in the control group at three years (P = .5). Temporary vascular shunting used as a damage control adjunct in management of wartime extremity vascular injury does not lead to worse outcomes. Benefit from TVS is suggested, but not statistically significant. Injury specific variables of venous ligation, associated fracture, and penetrating blast mechanism are associated with amputation. Amputation-free survival after vascular injury in Operation Iraqi Freedom is 79% at three years. Further studies to statistically define any possible benefits of TVS are needed.

Endovascular total aortic arch replacement by in situ stent graft fenestration technique

Open surgical total aortic arch replacement is a demanding procedure which carries a substantial morbidity and mortality. A less invasive endovascular option is endovascular stent grafting using in situ fenestrations. After thoracic stent graft deployment in the arch, fenestrations are made for the major arch vessels. During this procedure, antegrade cerebral perfusion is maintained using a temporary bypass from the left femoral artery to both carotids perfusing both the anterior and posterior cerebral circulation. The endovascular technique and devices used are herein described.

Ischemic prevention for stent implantation via brachial artery in children

An 11-year-old boy received stent implantation for peripheral pulmonary stenosis through the left modified Blalock-Taussig shunt from the left brachial approach because of the hairpin-shaped route from a femoral or carotid approach. A temporary bypass between the left radial and the femoral arteries was established to prevent ischemic complication of the left forearm. There was no ischemic change of the left forearm in the physiological monitoring despite the long procedure (more than 4 hr) and brachial arterial spasms. No complications occurred after the procedure. The temporary bypass will support fewer complications in various catheter interventions through a brachial arterial approach in children.

Portoumbilical Anastomosis as a Simple Method of Transient Portosystemic Shunt During Liver Transplantation

Background This article describes a new method of transient intraoperative portosystemic shunting, Splachnic edema after portal cross-clamping can be a dangerous complication during the anhepatic phase of the liver transplant operation. The current method seeks to avoid this problem, without the use of external venovenous bypass pump, by a temporary portocaval shunt, with retrohepatic cava preservation as first described experimentally in dogs by Fonkalsrud et al in 1966. Methods and Results Among 227 liver transplant operations, we utilized a transient portosystemic shunt in 29 cases. The indication to perform a temporary shunt in all cases was the development of splachnic edema. In 3 instances, we performed a portoumbilical anastomosis using a prominent umbilical vein. The other 26 procedures employed the usual portocaval shunts. In these cases, splachnic congestion and onset of edema developed after cross-clamping of the round ligament and the portal vein, which resolved after the portoumbilical anastomosis. Discussion The flow in the shunt was in all cases greater than 1 L/min. The most important risk factor for the development of splachnic edema was the presence of a patent umbilical vein, which occurred in 34.5% of shunted patients. Conclusion The use of a patent umbilical vein to perform a portoumbilical shunt was an effective, easy method to decompress the splachnic area, avoiding dangerous congestion and edema.

Temporary Endovascular Bypass: A Novel Treatment for Acute Stroke: Fig 1.

Intracranial stent placement is emerging as an effective treatment for acute stroke. As a means to avoid stent-associated complications and capitalize on stent-placement-related advantages, the concept of a "temporary endovascular bypass" (TEB) for stroke therapy was recently reported. In this technique, a stent is temporarily deployed for instant recanalization. Once sufficient flow is established to maintain vessel patency, the stent is recaptured and withdrawn. We report a second case to further characterize the merits of TEB.

Association of mesenteric portovenographic findings with outcome in cats receiving surgical treatment for single congenital portosystemic shunts

To determine whether hepatic portal vascularity assessed via intraoperative mesenteric portovenography (IMP) is related to outcome in cats undergoing surgical attenuation of a congenital portosystemic shunt (CPSS). Retrospective case series. 25 cats, each with 1 CPSS, in which IMP was performed before and after temporary complete occlusion of the shunting vessel to provide complete (n=9) or partial (16) shunt attenuation. Medical records were reviewed for signalment, clinical history, postoperative complications, clinical outcome, and results of bile acids stimulation testing. Portovenograms obtained before and after shunt occlusion were graded to determine whether degree of intrahepatic portal branching was correlated with degree of shunt attenuation, clinical or biochemical factors, postoperative complications, or outcome. In 12 of the 16 cats that had partial CPSS attenuation, procedures were later repeated to achieve complete (n=9) and additional partial (1) CPSS attenuation. Degree of opacification of the intrahepatic portal vessels increased significantly (higher portovenogram grade) after CPSS attenuation. The median portovenogram grade assigned after temporary shunt occlusion at the first surgery was significantly higher in cats that did not have postattenuation neurologic complications or neurologic signs at follow-up than in cats that did. It was also higher in cats that had a better clinical response to surgery versus those that had a poor response and in cats with reduced preprandial and postprandial serum bile acids concentrations at follow-up versus those that did not. IMP may be used to help predict complications and outcome following surgical treatment of CPSS in cats.