Intermittent Vascular Occlusion Research Articles

Brief cycles of lower-limb occlusion accelerate recovery kinetics in soccer players

ABSTRACT Objective: The aim of this study was to assess the effect of intermittent vascular occlusion (IVO) on recovery following simulated soccer physical demand test in soccer players. Methods: Twelve soccer players completed the Loughborough Intermittent Shuttle Test (LIST) in two conditions placebo (PLA) and IVO followed by intermittent lower-limb occlusion. Physical performance (Squat jump: SJ, countermovement jump: CMJ, maximal voluntary contraction: MVC, and 20 m sprint: SP), muscle damage parameters (creatine kinase: CK, Lactate dehydrogenase: LDH), inflammatory parameter (C-reactive protein: CRP), and perceived muscle soreness (DOMS) were assessed before, immediately after (0 h), and 24 h, 48 h, and 72 h following the exercise. Results: Following the LIST, a decrease was observed in all Physical performance within 48 h in PLA condition (p < 0.05), compared to PLA treatment, IVO treatment attenuated the decrease of SJ and CMJ at 24 h and at 48 h and for MVC and SP within 48 h after the LIST (p < 0.05). CK and LDH levels increased within 24 h post-exercise in both conditions (p < 0.05), but with a lower level in IVO compared to PLA condition (p < 0.05). Likewise, DOMS values were significantly lower with IVO condition compared to PLA condition immediately and at 24 h after exercise. Conclusion: The results of the present study suggest that the application of IVO after simulated soccer physical demand test accelerated recovery kinetics in soccer players.

Comparison of Early Clinical Outcomes between Intermittent Vascular Inflow Occlusion versus Intermittent Selective Hepatic Vascular Exclusion in Hepatic Resections for Cholangiocarcinoma Patients: A Prospective Randomized Controlled Trial Study

Background: There were reported benefits of selective hepatic vascular exclusion (SHVE) in reducing intraoperative blood loss (IBL), intraoperative packed red cell (PRC) transfusion, and perioperative complications over intermittent Pringle maneuver (IPM) in hepatectomies. However, there was lack of data regarding the use of SHVE in comparison with IPM in hepatectomies for cholangiocarcinoma (CCA) patients. Objective: To compare IBL, intraoperative PRC transfusion, total operative time (TOT), and perioperative complications between SHVE and IPM. Materials and Methods: Between October 2018 and September 2019, forty eligible CCA patients participated in the study. They were randomly allocated to the SHVE group (n=20) or the IPM group (n=20). Data regarding patient demographics, tumor characteristics, and the objectives of the study were gathered and analyzed with intention-to-treat principle. Results: The median IBL (range) 923.5 (101 to 4,979) versus 1,109 (413 to 5,305) ml; p=0.2, median intraoperative PRC transfusion (range) 112.5 (0 to 1,745) versus 296 (0 to 1,500) ml; p=0.22, and median TOT (range) 390 minute (220 to 915) versus 320 (240 to 930) minutes; p=0.55 between SHVE and IPM were not significantly different. There was no statistical difference in perioperative complications between SHVE and IPM. Conclusion: Routine use of SHVE during hepatectomies in CCA patients showed no significant difference in outcomes regarding the objectives of the study. Keywords: Selective hepatic vascular exclusion (SHVE), Hepatic vascular exclusion with preservation of caval flow (HVEPV), Hepatic resection, Cholangiocarcinoma, Intraoperative blood loss, Perioperative complications

Intermittent regional hepatic vascular inflow occlusion for laparoscopic right anterior sectionectomy

Objective To compare the efficacy and safety of intermittent regional hepatic vascular inflow occlusion with Pringle’s maneuvre for laparoscopic anterior sectionectomy. Methods From January 2014 to December 2018, 54 patients who underwent laparoscopic right anterior sectionectomy at the Department of Hepatopancreatobiliary Surgery, the Third Affiliated Hospital, Soochow University were recruited into this study. The patients were 40 to 60 years old, and 27 were males and 27 females. Intermittent regional hepatic vascular inflow occlusion was carried out in 24 patients (the intermittent occlusion group). The remaining patients underwent Pringle’s maneuvre (the Pringle group). Postoperative liver function, intraoperative blood loss, intraoperative blood transfusion, operation time and postoperative complications between the two groups were compared. Results Intraoperative hemorrhage and blood transfusion of the Pringle group (534±42)ml, (2.88±0.54)U were significantly higher than the intermittent occlusion group (374±21)ml, (1.86±0.29)U (all P 0.05). Conclusion Intermittent regional hepatic vascular inflow occlusion reduced intra-operative hemorrage and hepatic impairment, and shortened hospital stay. However, it required higher operation skills and it should gradually be promoted. Key words: Hepatectomy; Laparoscopes; Inflow occlusion; Liver function

The Role of SOD2 in Maintaining Endothelial Cell Function in SCD

Sickle cell disease (SCD) is characterized by increased oxidative stress. Sources of oxidative stress include (1) intermittent vascular occlusion resulting in hypoxia-reoxygenation induced activation of prooxidant enzymes such as xanthine oxidase and NADPH oxidase, (2) increased fragility of red blood cell membranes causing hemolysis and release of free hemoglobin and heme which produce reactive oxygen species (ROS) through Fenton chemistry, and (3) respiratory chain leaked electrons reacting with oxygen to form superoxide. In SCD, the antioxidant defense system has been shown to be insufficient in its response to increased ROS production. In particular, peripheral blood expression of the mitochondrial targeted antioxidant superoxide dismutase 2 (SOD2) is decreased in SCD patients relative to non-sickle controls. We hypothesize that depletion of SOD2 may modify the progression of sickle pathology. In order to test our hypothesis we (Aim 1) genotyped 410 SCD patients from the Treatment of Pulmonary Hypertension and Sickle Cell Disease with Sildenafil Therapy (walk-PHaSST) study for a common polymorphism of SOD2 (rs4880), valine to alanine on the 16thamino acid (V16A), and investigated whether or not the polymorphism is associated with clinical indicators of endothelial dysfunction. (Aim 2) In primary human pulmonary arterial endothelial cells (hPAECs) we utilized an siRNA mediated knockdown of SOD2 (SOD2 KD) in order to examine its role in maintaining endothelial cell permeability. Permeability was measured by using electric-cell substrate impedance sensing (ECIS). In Aim 1, among the 410 SC anemia patients 129 (31%), 64 (16%) and 217 (53%) were homozygotes for the common valine allele (TT), homozygotes for the variant alanine allele (CC) and heterozygotes (TC), respectively. We examined association of each genotype with the following clinical parameters: history of pulmonary embolism, systolic blood pressure (SBP), pulse blood pressure, hemoglobin, mean corpuscular value, reticulocyte count, white blood cell count, platelet count, tricuspid regurgitant velocity (TRV), left mass index, right atrial area, left ventricle, right ventricular area at systolic, creatinine, six minute walk distance (6MWD). We found that homozygotes of alanine variant (CC) had higher systolic blood pressure (p=0.011), higher TRV (p=0.004), larger right ventricular area at systolic (p=0.023), as well as shorter 6MWD (p=0.006). All four of these clinical parameters are strong indicators of vasculopathy and endothelial damage. Based on our clinical findings, we extended our studies to isolated endothelial cells to define the role of SOD2 in endothelial cell permeability. In Aim 2, we used ECIS in order to measure resistance in SOD2 KD hPAECs. Decreased resistance as measured by ECIS has been shown to be an indicator of increased permeability. We found that SOD2 KD hPAECs had decreased baseline resistance as compared to hPAECs treated with a non-targeting siRNA sequence (siNT). This data supports that SOD2 plays a role in maintaining endothelial cell barrier function. We also, investigated whether free hemin would further accentuate endothelial barrier dysfunction in SOD2 KD cells. We serum starved siNT and siSOD2 KD hPAECs for four hours before treating with 2 mM hemin and measuring resistance. We found that after four hours of 2 mM hemin treatment, there was no further reduction of resistance in SOD2 KD hPAECs as compared to siNT hPAECs. In conclusion, we have found that in SCD patients SOD2 V16A is associated with clinically significant indicators of endothelial dysfunction and SOD2 is essential for the maintenance of endothelial cell barriers in hPAECs. Future directions will be aimed at further investigating the SOD2 V16A polymorphism, specifically we are interested in whether the polymorphism plays a role in barrier function. We will also investigate the pathways by which SOD2 depletion mediates endothelial cell barrier function. Taken together, our preliminary findings suggest that SOD2 functions as an essential mediator of endothelial function in SCD and thus can be used as a target for future SCD therapeutics. Disclosures Straub: Bayer Pharmaceuticals: Research Funding.

A novel very simple laparoscopic hepatic inflow occlusion apparatus for laparoscopic liver surgery.

Control of bleeding is extremely important for laparoscopic liver resection. We introduce a new and operationally simple laparoscopic hepatic inflow occlusion apparatus (LHIOA) and its successful application in laparoscopic surgery for patients with cirrhosis. The self-designed LHIOA was constructed using a tracheal catheter (7.5#) and infusion set. The tracheal catheter and infusion set were trimmed to 30 and 70cm, to serve as an occlusion tube and occlusion tape, respectively. After establishment of pneumoperitoneum, the occlusion tape was inserted to encircle the hepatoduodenal ligament. The occlusion tube was then introduced and the ends of the occlusion tape were pulled out of it to occlude the hepatic inflow. Under intermittent vascular occlusion with the LHIOA, the liver parenchyma was transected using an ultrasonic scalpel and monopolar electrocoagulation. Outcomes of the application of the LHIOA in hepatocellular carcinoma patients with cirrhosis (LHIOA group, n = 46) were compared with patients undergoing laparoscopic hepatectomy without LHIOA (non-LHIOA group, n = 46), using one-to-one propensity case-matched analysis. The LHIOA effectively occluded the hepatic inflow while showing no damage to the hepatoduodenal ligament. The time required for presetting the LHIOA is 6.8 ± 0.6min. The conversion rate in the non-LHIOA group was 13.0% while there was no conversion in the occlusion group (P < 0.001). The median blood loss of patients in the LHIOA group (60ml, range 50-200ml) was significantly less than that of patients in the non-LHIOA group (250ml, range 100-800) (P < 0.001). Transfusion was required in 8 patients in the non-LHIOA group while no transfusion was required in the LHIOA group. The median operative time in the LHIOA group (157min, range 80-217min) was significantly shorter than that in the non-LHIOA group (204min, range 105-278min) (P < 0.001). The new LHIOA is effective, safe, and simple. It can significantly reduce conversion rate, blood loss, and operative time. It facilitates laparoscopic liver resection and is recommended for use.

Muscle Oxidative Capacity Is Low In The Upper And Lower Limbs Of COPD Patients

Muscle atrophy, weakness and fatigability are characteristic of patients with chronic obstructive pulmonary disease (COPD), which contribute to dyspnea, exercise intolerance and morbidity. Comparisons between upper and lower limb performance suggests intrinsic differences in muscular adaptations between leg and arm muscles, with preserved biceps brachii endurance in COPD (Franssen et al. MSSE 37:2-9, 2005). We were therefore interested whether loss of muscle oxidative capacity was different between upper and lower limbs in COPD. PURPOSE: To compare muscle oxidative capacity in the upper and lower limbs between smokers with or without COPD. METHODS: 19 COPD patients (GOLD 2/3/4, n=7/6/6; FEV1%pred 44.1±18.7; M/F=14/5) and 18 smokers with normal spirometry (CON; M/F=14/4) volunteered. Non-dominant medial forearm and medial gastrocnemius oxidative capacity was assessed from the O2 consumption recovery rate constant (k) following brief muscle contractions using near-infrared spectroscopy with intermittent vascular occlusion. k was estimated from the mean of two repetitions. Differences were determined by 2-way ANOVA (group x limb). RESULTS: There was a significant main effect of group on muscle oxidative capacity (F=11.7, ηp2=0.14, p<0.001): COPD patients had significantly lower k in both upper and lower limb muscles (upper 1.01±0.17, lower 1.05±0.24 min-1) compared with CON (1.27±0.49, 1.49±0.67 min-1). However, there was no effect of limb (F=1.8, ηp2=0.03, p=0.18) and no group x limb interaction. CONCLUSION: We found that muscle oxidative capacity is lower in COPD than controls in both upper and lower limbs. Although, when compared to age- and sex-matched smokers with normal spirometry, k tended to be more reduced in the gastrocnemius (-30%) than the forearm (-20%) of COPD patients, this difference was not significant. Unlike previous findings, these data suggest that muscle mitochondrial function is systemically impaired in COPD patients, and not simply the result of inactivity-induced deconditioning; which is expected to manifest as greater impairments in lower limb than upper limb. The variables contributing to systemic deficiency in muscle oxidative capacity in COPD warrant further study. Supported by SNSF P300PB_167767; PERF; ATS Foundation/Breathe California of Los Angeles

Hypothermic perfusion with retrograde outflow during right hepatectomy is safe and feasible

In situ hypothermic perfusion during liver resection performed under vascular inflow occlusion decreases hepatic ischemia-reperfusion injury, but technical limitations have restricted its widespread use. In situ hypothermic perfusion with retrograde outflow circumvents these impediments and thus could extend the applicability of in situ hypothermic perfusion. The safety and feasibility of in situ hypothermic perfusion with retrograde outflow were analyzed in selected patients undergoing right (extended) hepatectomy and compared to intermittent vascular inflow occlusion, the gold standard method, in this randomized pilot study. Patients were first screened for parenchymal liver disease (exclusion criteria: steatosis ≥30%, cirrhosis, or cholestasis). Study participants were randomized intraoperatively to undergo in situ hypothermic perfusion with retrograde outflow (n=9) or intermittent vascular inflow occlusion (n=9). The target liver core temperature during in situ hypothermic perfusion with retrograde outflow was 28°C. The primary end point was ischemia-reperfusion injury (expressed by peak postoperative transaminase levels). Secondary outcomes included functional liver regeneration (assessed by hepatobiliary scintigraphy) and clinical outcomes. Peak transaminase levels, total bilirubin, and the international normalized ratio were similar between both groups, although a trend toward more rapid normalization of bilirubin levels was noted for the in situ hypothermic perfusion with retrograde outflow group. Functional liver regeneration as evaluated by hepatobiliary scintigraphy was improved on postoperative day 3 fafter in situ hypothermic perfusion with retrograde outflow but not after intermittent vascular inflow occlusion. Furthermore, in situ hypothermic perfusion with retrograde outflow (requiring continuous ischemia) was comparable to intermittent vascular inflow occlusion for all clinical outcomes, including postoperative complications and hospital stay. The use of in situ hypothermic perfusion with retrograde outflow appears to be safe and feasible in selected patients with healthy liver parenchyma and may benefit early functional liver regeneration. Future applications of in situ hypothermic perfusion with retrograde outflow include patients with damaged liver parenchyma who would require major hepatic resection with a prolonged vascular inflow occlusion duration.

Anaesthetic challenges in a child with sickle-cell disease and congenital heart block.

Sir, We present a case report of anaesthetic management of a 12-year-old boy with sickle-cell disease (SCD) and congenital heart block (CHB) with pacemaker [Figure 1], undergoing laparoscopic splenectomy.Figure 1: 12-lead electrocardiography of the patientThe child had suffered sickle-cell crisis and pacemaker malfunction a month back. His preoperative investigations were normal and weight was 30 kg. He received intravenous (IV) fluids during fasting period, pneumococcal vaccine, antibiotic prophylaxis and cefotaxime 500 g IV. The cardiologist changed the mode of pacemaker to asynchronous (fixed rate). Standard American Society of Anesthesiologists monitoring, urine output and temperature monitoring were used. Morphine 4.5 mg IV, thiopentone 150 mg IV and atracurium 0.5 mg/kg IV were used for induction and intubation. Anaesthesia was maintained with isoflurane (MAC: 1.0), air and oxygen (FiO2: 0.5). Pneumoperitoneum was created with CO2 and intra-abdominal pressure was kept around 8–10 mmHg. The surgeon used bipolar cautery, blood loss was approximately 800 ml and 1 unit packed red cell was transfused. The patient was given fluid at 60 ml/h intra-operatively as he had been kept hydrated preoperatively. For post-operative analgesia, paracetamol 500 mg IV was given and skin incision was infiltrated with 12 ml 0.2% ropivacaine. Neuromuscular blockade was reversed and trachea was extubated. The patient remained haemodynamically stable, normothermic and had adequate urine output. Post-operative analgesia was maintained with paracetamol 500 mg IV 8th hourly and fentanyl boluses of 30 μg as rescue analgesic whenever visual analogue scale exceeded 3. The child was discharged on the 7th post-operative day after uneventful course. CHB (incidence 1 in 22,000 live births) with no structural abnormality and when diagnosis is established beyond neonatal period has better survival.[1] Intraoperatively, pacemaker mode is advised to be changed to asynchronous, and bipolar electrocautery is to be used. The availability of manual pacing should be ensured to manage pacemaker malfunction.[2] SCD is the disorder of beta-globin chain characterised by haemolytic anaemia, intermittent vascular occlusion, pulmonary compromise and multi-organ damage. Electrocardiogram changes are non-specific and first-degree heart block may be found.[34] Not usually associated with SCD, CHB in our patient is perhaps an additional finding. Splenectomy is recommended in children older than 2 years or after one major or two minor episodes of splenic sequestration crises.[34] When done laparoscopically, the duration of surgery increases, but hospital stay is decreased.[3] Any major surgery is associated with 7% mortality. Preoperatively, the history of episodes of painful crises must be sought.[4] Pre-operative examination should be thorough as SCD involves multiple organ systems. Neurological evaluation rules out the previous cerebrovascular accident as ischaemic infarcts are common in anaemic children.[3] Kidneys may get involved during advanced disease. Presence of rib infarcts can lead to hypoventilation. Perioperative cardiopulmonary manifestations such as acute chest syndrome usually remain undetected in young children.[34] As dehydration precipitates RBC sickling and occlusion of microvasculature at a level of precapillary sphincters, perioperative hydration must be ensured.[34] There is a controversy regarding blood transfusion, benefit being dilution of haemoglobin S and disadvantage being triggering of sickling.[34] Other factors leading to sickling crises are vascular stasis, hypoxia, metabolic acidosis, hypothermia and presence of infection.[3] Previous case reports have emphasised the importance of preventing sickling crisis perioperatively.[5] To conclude, perioperative anaesthetic management of children suffering from SCD and CHB needs meticulous pre-operative and intra-operative management and post-operative vigilance for preventing sickle-cell crisis and associated complications. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Hepatic cytoprotective effect of ischemic and anesthetic preconditioning before liver resection when using intermittent vascular inflow occlusion: A randomized clinical trial

Ischemic preconditioning (IPC) and anesthetic preconditioning (APC) have been reported to attenuate ischemia-reperfusion (IR) injury after liver resection under continuous inflow occlusion. This study evaluates whether these strategies enhance hepatic protection of remnant liver against IR after liver resection with intermittent clamping (INT). A total of 106 patients without underlying liver disease and submitted to liver resection using INT were randomized into 3 groups: IPC (10 minutes of inflow occlusion followed by 10 minutes of reperfusion before liver transection), APC (sevoflurane administration for 20 minutes before liver transection), and INT (no preconditioning). Patients were also stratified according to the extent of the hepatectomy. Cytoprotection was evaluated by comparing hepatocyte and endothelial dysfunction markers, apoptosis, histologic lesions, and postoperative outcome. No differences were observed in preoperative chemotherapy and steatosis, total warm ischemia time, operative time, or blood loss. Kinetics of transaminases (aspartate aminotransferase, P = .137; alanine aminotransferase, P = .616), bilirubin (P = .980), and hyaluronic acid increase (P = .514) revealed no differences. Significant apoptosis was present in 40% of patients, mild-to-moderate leukocyte infiltration and steatosis in 45% and 55%, respectively, and mild sinusoidal congestion in 65%, with a similar distribution in the 3 groups. When patients were stratified by major versus minor resections, no differences were observed in any of the variables studied. Postoperative clinical outcomes were also similar. These results suggest that these protocols of IPC and APC used in this study do not provide better cytoprotection from IR when INT is used.

Teaching Neuro Images : Intermittent symptomatic occlusion of the vertebral artery caused by a cervical osteophyte

A 77-year-old man presented with 2 episodes of waking up with symptoms of vertebrobasilar ischemia (figure, A and B) within 6 months. A CT angiogram showed narrowing of the right vertebral artery due to extrinsic compression by an osteophyte of the superior articular process of the fourth cervical vertebra, compromising the foramen transversarium (figure, C and D). Dynamic angiography demonstrated intermittent vascular occlusion associated with head turning (figure, E-G). After recurrence, surgical decompression of the vertebral artery was performed. Extrinsic compressions of the vertebral artery is rare.(1) The most frequent signs are those of vertebrobasilar insufficiency. Surgical treatment has been proposed when conservative management fails.(1).

Useful and convenient procedure for intermittent vascular occlusion in laparoscopic hepatectomy

While the amount of blood loss during laparoscopic hepatectomy tends to be smaller than that during open hepatectomy, intermittent vascular occlusion to control hepatic inflow can diminish blood loss during laparoscopic hepatectomy. Described herein is a useful and convenient method for intermittent vascular occlusion, which was standardized for laparoscopic hepatectomy. A tourniquet system consisting of cloth tape and a 20-cm catheter was used for intermittent vascular occlusion. This was placed through a hole in the abdominal wall from which a 5-mm trocar had been extracted. By operating this tourniquet system outside the patient's body, we were easily able to repeat intermittent vascular occlusion. Twenty-three patients underwent laparoscopic hepatectomy using this system. The mean time of operation and vascular occlusion were 311.6 and 83.6 min, respectively. The mean blood loss was 215.0 mL. There were no intraoperative blood transfusions or critical postoperative complications. The average length of postoperative hospital stay was 6.5 days. The mean time to place this system was 354 s, and there were no complications caused by this system. During totally laparoscopic hepatectomy, surgeons can perform intermittent vascular occlusion safely by using this method.

Ischemic preconditioning may reduce hyperglycemia associated with intermittent Pringle maneuver in hepatic resection

We read with considerable interest the article ‘‘Ischemic preconditioning prior to intermittent Pringle maneuver in liver resections’’ by Winbladh et al. [1] in the Journal of Hepatobiliary Pancreatic Science. In a study of 32 hepatectomized patients, ischemic preconditioning (IP) before intermittent vascular occlusion using the Pringle maneuver seemed to improve aerobic glucose metabolism, as evidenced by reductions in liver glucose, pyruvate, and lactate levels, compared with the control group without IP. Of particular interest, postoperative hyperglycemia in the IP group was significantly lower than that in the control group. Herein, we share our opinions and provide support for this new finding from our own studies [2–4]. In both experimental [2] and clinical [3] studies using the Pringle maneuver, we found that hyperglycemia was caused by hepatic ischemia–reperfusion injury (IRI). During hepatic resection, blood glucose concentrations decreased marginally during clamping using the intermittent Pringle maneuver, but increased rapidly after unclamping [3]. Specifically, a rapid and profound transition to hyperglycemia was observed after unclamping when the intermittent Pringle maneuver was used during hepatectomy, and this transition may have involved glycogen breakdown within the hepatocytes due to hypoxia [3]. Okabayashi et al. [4] reported that not only was perioperative tight glycemic control (TGC) using an artificial pancreas (AP) to prevent hyperglycemia in hepatectomized patients more effective in reducing surgical site infection (SSI) than conventional glycemic control, but that it also had cost benefits by reducing the duration of the hospital stay. In the study of Winbladh et al. [1], IP significantly decreased postoperative hyperglycemia on postoperative day (POD) 2 in patients who either had two to three or more than three segments resected compared with the respective control groups. IP protects against hepatic IRI because it reduces endothelial cell apoptosis and ATP degradation in the immediate postischemic period [1]. On the basis of these results, it seems that IP may reduce the hyperglycemia caused by disturbance of the hepatic glucose metabolism in association with IRI. Combination therapy of IP plus TGC, using an AP, may be a novel method to achieve glycemic control in patients who have undergone hepatectomy in which an intermittent Pringle maneuver was used, with less postoperative hyperglycemia resulting in reductions in SSI and a shorter hospital stay. Further studies in a larger series of patients are warranted to address this issue.

Segment-oriented liver resections based on posterior intrahepatic glissonian approach

Segment-oriented liver resections can be performed effective by posterior intrahepatic approach. A significance of such resection - is that they are oncologically radical as well as parenchyma-sparing. Segmental liver resections were performed in 102 patients with liver tumors. Suprahilar control of the appropriate glissonean pedicle was achieved by the posterior intrahepatic approach. Liver parenchyma was transsected by ultrasonic dissector, under intermittent vascular occlusion (IVO). Pedicle was divided at the end of resection using "endo-GIA" vascular stapler. The overall transection time was 30,14+/-12,56 min. The amount of blood loss was 285,59+/-129,92 ml. The postoperative complication rate was 25,49%. R0 resection had 94 (92,16%) patients.There was no liver failure or perioperative death. Posterior intrahepatic approach for segmental resection is safe, can expedite the liver transection and reduce intraoperative hemorrhage. This approach provides adequate tumor clearance with preservation of normal parenchyma, as well as the vasculature or the biliary drainage of the contralateral liver.

Randomized clinical trial of ischaemic preconditioning in major liver resection with intermittent Pringle manoeuvre

Vascular inflow occlusion is effective in avoiding excessive blood loss during hepatic parenchymal transection but may cause ischaemic damage to the remnant liver. Intermittent portal triad clamping (IPTC) is superior to continuous hepatic pedicle clamping as it avoids severe ischaemia-reperfusion (IR) injury in the liver remnant. Ischaemic preconditioning (IPC) before continuous Pringle manoeuvre may protect against IR during major liver resection. This RCT assessed the impact of IPC in major liver resection with intermittent vascular inflow occlusion. Patients undergoing major liver resection with intermittent vascular inflow occlusion were randomized, during surgery, to receive IPC (10 min inflow occlusion followed by 10 min reperfusion) or no IPC (control group). Data analysis was on an intention-to-treat basis. The primary endpoint was serum alanine aminotransferase (ALT) level on the day after surgery. Eighty four patients were enrolled and randomized to IPC (n = 41) and no IPC (n = 43). The groups were comparable in terms of demographic data, preoperative American Society of Anesthesiologists grade and extent of liver resection. Intraoperative morbidity and postoperative outcomes were also similar. ALT levels on the day after operation were not decreased by IPC (mean(s.d.) 537·6(358·5) versus 525·0(400·6) units/ml in IPC and control group respectively; P = 0·881). Liver biochemistry tests in the week after operation showed the same pattern in both groups. IPC did not reduce liver damage in patients undergoing major liver resection with IPTC. NCT00908245 (http://www.clinicaltrials.gov).

Ischemic preconditioning prior to intermittent Pringle maneuver in liver resections

Continuous inflow vascular occlusion during liver resections causes less severe ischemia and reperfusion injury (IRI) if it is preceded by ischemic preconditioning (IP) or if intermittent inflow occlusion is used during the resection. No previous clinical trial has studied the effects of adding IP to intermittent inflow occlusion. Consecutive patients (n = 32) with suspicion of malignant liver disease had liver resections (minimum 2 segments) performed with inflow occlusion (intermittent clamping in a manner of 15 min of ischemia and 5 min of reperfusion repetitively; 15/5). Half of the patients were randomized to receive IP (10 min of ischemia and 10 min of reperfusion before parenchymal transection; 10/10). The patients were stratified according to volume of resection and none had chronic liver disease. The patients were followed for 5 days with microdialysis (μD). All patients completed the study and there were no deaths. No differences were seen between the groups regarding demographics or perioperative parameters (bleeding, duration of ischemia, resection volume, complications, and serum laboratory tests). There were no differences in alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, or prothrombin time (PT)-INR levels, but μD revealed lower levels of lactate, pyruvate, and glucose in the IP group having major liver resections (analysis of variance; ANOVA). Nitrite and nitrate levels in μD decreased postoperatively, but no differences were seen between the groups. In one patient an elevated μD-glycerol curve was seen before the diagnosis of a stroke was made. IP before intermittent vascular occlusion does not reduce the serum parameters used to assess IRI. IP seems to improve aerobic glucose metabolism, as the levels of glucose, pyruvate, and lactate locally in the liver were reduced, compared to controls, in patients having >3 segments resected. μD may be used to monitor metabolism locally.

Methods of vascular occlusion for elective liver resections

Vascular occlusion is used to reduce blood loss during liver resection surgery. There is considerable controversy regarding whether vascular occlusion should be used or not during elective liver resections. The method of vascular occlusion employed is also controversial. There is also considerable debate on the role of ischaemic preconditioning before vascular occlusion. To assess the advantages (decreased blood loss and peri-operative morbidity) and disadvantages (liver dysfunction from ischaemia) of vascular occlusion during liver resections. To compare the advantages (in decreasing blood loss or decreasing ischaemia-reperfusion injury) and disadvantages of different types of vascular occlusion versus total, continuous portal triad clamping. We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until March 2007. We included randomised clinical trials comparing vascular occlusion versus no vascular occlusion during elective liver resections (irrespective of language or publication status). We also included randomised clinical trials comparing the different methods of vascular occlusion and those investigating the role of ischaemic preconditioning in liver resection. We collected the data on the characteristics of the trial, methodological quality of the trials, mortality, morbidity, blood loss, blood transfusion requirements, liver function tests, markers of neutrophil activation, operating time, and hospital stay. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For each binary outcome we calculated the odds ratio (OR) with 95% confidence intervals (CI) based on intention-to-treat analysis. For continuous outcomes, we calculated the weighted mean difference (WMD) with 95% confidence intervals. We identified a total of 16 randomised trials. Five trials including 331 patients compared vascular occlusion (n = 166) versus no vascular occlusion (n = 165). Six trials including 521 patients compared different methods of vascular occlusion. Three trials including 210 patients compared ischaemic preconditioning before continuous portal triad clamping (n = 105) versus no ischaemic preconditioning (n = 105). Two trials including 127 patients compared ischaemic preconditioning before continuous portal triad clamping (n = 63) versus intermittent portal triad clamping (n = 64).The blood loss was significantly lower in vascular occlusion compared with no vascular occlusion. The liver enzymes were significantly elevated in the vascular occlusion group compared with no vascular occlusion. There was no difference in the mortality, liver failure, or other morbidities. Four of the five trials comparing vascular occlusion and no vascular occlusion used intermittent vascular occlusion. Trials comparing complete inflow and outflow occlusion to the liver, ie, hepatic vascular exclusion and portal triad clamping demonstrate significant detrimental haemodynamic changes in hepatic vascular exclusion compared to portal triad clamping. There was no significant difference in the number of units transfused and the number of patients needing transfusion. There was no difference in mortality, liver failure, or morbidity between total and selective methods of portal triad clamping. All four cases of mortality and liver failure in the comparison between the intermittent and continuous portal triad clamping occurred in the continuous portal triad clamping (statistically not significant). Intermittent portal triad clamping does not increase the total blood loss or operating time compared to continuous portal triad clamping.There was no statistically significant difference in the mortality, liver failure, morbidity, blood loss, or haemodynamic changes between ischaemic preconditioning versus no ischaemic preconditioning before continuous portal triad clamping. Liver enzymes used as markers of liver injury were significantly lower in the early post-operative period in the ischaemic preconditioning group. The intensive therapy unit stay and hospital stay were statistically significantly lower in the ischaemic preconditioning group than in the no ischaemic preconditioning group.There was no statistically significant difference in the mortality, liver failure, morbidity, intensive therapy unit stay, or hospital stay between ischaemic preconditioning before continuous portal triad clamping and intermittent portal triad clamping. The blood loss and transfusion requirements were lower in the ischaemic preconditioning group. Aspartate aminotransferase level was lower in the intermittent portal triad clamping group than the ischaemic preconditioning group on the third post-operative day. There was no difference in the peak aspartate aminotransferase levels or in the aspartate aminotransferase levels on first or sixth post-operative days of aspartate aminotransferase . Intermittent vascular occlusion seems safe in liver resection. However, it does not seem to decrease morbidity. Among the different methods of vascular occlusion, intermittent portal triad clamping has most evidence to support the clinical application. Hepatic vascular exclusion cannot be recommended routinely. Ischaemic preconditioning before continuous portal triad clamping may be of clinical benefit in reducing intensive therapy unit and hospital stay.

Vascular occlusion for elective liver resections

Vascular occlusion is used to reduce blood loss during liver resection. There is considerable controversy regarding whether vascular occlusion should be used or not during elective liver resections. To assess the advantages (decreased blood loss and peri-operative morbidity) and disadvantages (ischaemia-reperfusion injury related complications like liver dysfunction) of vascular occlusion during elective liver resections. We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until August 2008. We included randomised clinical trials comparing vascular occlusion versus no vascular occlusion during elective liver resections (irrespective of language or publication status). Two authors independently assessed trials for inclusion and independently extracted the data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. We calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) based on intention-to-treat or available case analysis. We identified a total of five trials (of high bias-risk) which compared vascular occlusion (n = 166) versus no vascular occlusion (n = 165). Three of the five trials comparing vascular occlusion and no vascular occlusion used intermittent vascular occlusion. There was no difference in mortality, liver failure, or other morbidities. The blood loss was significantly lower in vascular occlusion compared with no vascular occlusion. The liver enzymes were significantly elevated in the vascular occlusion group compared with no vascular occlusion. Intermittent vascular occlusion seems safe in liver resection. However, it does not seem to decrease morbidity. More randomised trials seem to be needed.

Methods of vascular occlusion for elective liver resections

Vascular occlusion is used to reduce blood loss during liver resection surgery. Various methods of vascular occlusion have been suggested. To compare the benefits and harms of different methods of vascular occlusion during elective liver resection. We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until August 2008. We included randomised clinical trials comparing different methods of vascular occlusion during elective liver resections (irrespective of language or publication status). Two authors independently assessed trials for inclusion and independently extracted the data. We calculated the risk ratio or mean difference with 95% confidence intervals using fixed-effect and random-effects models based on intention-to-treat or available data analysis. Ten trials including 657 patients compared different methods of vascular occlusion. All trials were of high risk of bias. Only one or two trials were included under each comparison. There was no statistically significant differences in mortality, liver failure, or other morbidity between any of the comparisons.Hepatic vascular occlusion does not decrease the blood transfusion requirements. It decreases the cardiac output and increases the systemic vascular resistance. In the comparison between continuous portal triad clamping and intermittent portal triad clamping, four of the five liver failures occurred in patients with chronic liver diseases undergoing the liver resections using continuous portal triad clamping. In the comparison between selective inflow occlusion and portal triad clamping, all four patients with liver failure occurred in the selective inflow occlusion group. There was no difference in any of the other important outcomes in any of the comparisons. In elective liver resection, hepatic vascular occlusion cannot be recommended over portal triad clamping. Intermittent portal triad clamping seems to be better than continuous portal triad clamping at least in patients with chronic liver disease. There is no evidence to support selective inflow occlusion over portal triad clamping. The optimal method of intermittent portal triad clamping is not clear. There is no evidence for any difference between the ischaemic preconditioning followed by vascular occlusion and intermittent vascular occlusion for liver resection in patients with non-cirrhotic livers. Further randomised trials of low risk of bias are needed to determine the optimal technique of vascular occlusion.

Ischemic preconditioning and intermittent clamping confer protection against ischemic injury in the cirrhotic mouse liver

Surgery on cirrhotic livers is fraught with complications, and many surgeons refrain from operating on patients with cirrhosis. Surgical procedures include temporal occlusion of blood flow resulting in ischemia. The mechanisms of protective strategies to prevent ischemic injury in patients with cirrhosis are not fully understood. The aim of this study was to evaluate how the cirrhotic liver tolerates an ischemic insult, whether mechanisms other than those observed in the normal liver are active, and whether intermittent clamping and preconditioning, which are known as safe surgical strategies in normal and steatotic livers, confer protection to the cirrhotic liver. We applied partial hepatic inflow occlusion to cirrhotic mice fed carbon tetrachloride according to different vascular occlusion protocols: intermittent clamping with 15 or 30 minute cycles of ischemia or ischemic preconditioning prior to 60 or 75 minutes of ischemia. Continuous ischemia (60 or 75 minutes) served as controls. The results showed that the cirrhotic liver was significantly more susceptible to 60 minutes of ischemia than the normal liver. Apoptosis was higher in the normal liver, whereas necrosis was a predominant feature in the cirrhotic liver. Both protocols of intermittent vascular occlusion and ischemic preconditioning dramatically prevented injury compared to continuous occlusion for 60 minutes. This protection was associated with reduced necrosis and apoptosis, and particularly reduced activation of the apoptotic pathway through mitochondria. In conclusion, this study extends the protective effects of ischemic preconditioning and intermittent clamping to the cirrhotic liver, highlighting a diminished apoptotic pathway with dramatic improvement in the development of necrosis.

Ischemic preconditioning versus intermittent vascular occlusion in liver resections performed under selective vascular exclusion: a prospective randomized study

Background The aim of this study was to compare ischemic preconditioning with the intermittent vascular occlusion technique in liver resections performed under inflow and outflow occlusion. Methods Fifty-four patients with resectable liver tumors assigned were randomly to undergo surgery with either ischemic preconditioning (IP group, n = 27) or with intermittent vascular occlusion (IVO group, n = 27). Both groups were compared regarding surgical parameters, aspartate transaminase levels, and apoptosis. Results For warm ischemic time less than 40 minutes, no significant difference was noticed between the 2 groups apart from caspase-3 activity, which was higher in the IVO group than in the IP group (17.2 ± 3.4 vs. 10.3 ± 5.2, P < .05). When warm ischemia exceeded 40 minutes, the IP group showed higher levels in blood aspartate transaminase levels on day 3 (442 ± 178 IU/L vs. 305 ± 104 IU/L, P < .05) and higher caspase-3 levels (26.5 ± 5.7 count/high-power field [hpf] vs. 20.7 ± 3.6 count/hpf, P < .05) and apoptotic activity (28.5 ± 7.5 count/hpf vs. 20.2 ± 4.1 count/hpf, P < .05), as compared with the IVO group. Conclusions Although both techniques showed comparable efficacy for short ischemic times, intermittent vascular occlusion provided better cytoprotection when ischemia exceeded 40 minutes.