Complete versus selective portal triad clamping for minor liver resections: a prospective randomized trial. A prospective, randomized, controlled trial comparing intermittent portal triad clamping versus ischemic preconditioning with continuous clamping for major liver resection. Portal triad clamping or hepatic vascular exclusion for major liver resection. A controlled study. Continuous versus intermittent portal triad clamping during hepatectomy in cirrhosis. Results of a prospective, randomized clinical trial. Occlusion of hepatic blood inflow for complex central liver resections in cirrhotic patients: a randomized comparison of hemihepatic and total hepatic occlusion techniques. Ischemic preconditioning versus intermittent vascular occlusion in liver resections performed under selective vascular exclusion: a prospective randomized study. Continuous versus intermittent portal triad clamping for liver resection: a controlled study. The effect of hepatic vascular inflow occlusion on liver tissue pH, carbon dioxide, and oxygen partial pressures: defining the optimal clamp/release regime for intermittent portal clamping. Ischemic preconditioning improves postoperative outcome after liver resections: a randomized controlled study. Ischemic preconditioning for major liver resection under vascular exclusion of the liver preserving the caval flow: a randomized prospective study.
To evaluate the feasibility, safety, efficacy, amount of hemorrhage, postoperative complications, and ischemic injury of selective clamping in patients undergoing minor liver resections.
                Inflow occlusion can reduce blood loss during hepatectomy. However, Pringle maneuver produces ischemic injury to the remaining liver. Selective hemihepatic vascular occlusion technique can reduce the severity of visceral congestion and total liver ischemia.
                Eighty patients undergoing minor hepatic resection were randomly assigned to complete clamping (CC) or selective clamping (SC). Hemodynamic parameters, including portal pressure and the hepatic venous pressure gradient (HVPG), were evaluated. The amount of blood loss, measurements of liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), and postoperative evolution were also recorded.
                No differences were observed in the amount of hemorrhage (671 +/- 533 mL versus 735 +/- 397 mL; P = 0.54) or the patients that required transfusion (10% versus 15%; P = 0.55). There were no differences on postoperative morbidity between groups (38% versus 29%; P = 0.38). Cirrhotic patients with CC had significantly higher ALT (7.7 +/- 4.6 versus 4.5 +/- 2.7 mukat/L, P = 0.01) and AST (10.2 +/- 8.7 versus 4.9 +/- 2.1 mukat/L; P = 0.03) values on the first postoperative day than SC. The multivariate analysis demonstrated that high central venous pressure, HVPG >10 mm Hg, and intraoperative blood loss were independent factors related to morbidity.
                Both techniques of clamping are equally effective and feasible for patients with normal liver and undergoing minor hepatectomies. However, in cirrhotic patients selective clamping induces less ischemic injury and should be recommended. Finally, even for minor hepatic resections, central venous pressure, HVPG, and intraoperative blood loss are factors related to morbidity and should be considered. To evaluate whether ischemic preconditioning (IP) with continuous clamping or intermittent clamping (IC) of the portal triad confers better protection during liver surgery.
                IP and IC are distinct protective approaches against ischemic injury. Since both strategies proved to be superior in randomized controlled trials (RCTs) to continuous inflow occlusion alone, we designed a RCT to compare IP and IC in patients undergoing major liver resection.
                Noncirrhotic patients undergoing major liver resection were randomized to receive IP with inflow occlusion (n = 36) or IC (n = 37). Primary endpoints were postoperative liver injury and intraoperative blood loss. Postoperative liver injury was assessed by peak values of AST (alanine aminotransferase) and ALT (aspartate aminotransferase), as well as the area under the curve (AUC) of the postoperative transaminase course. Secondary endpoints included resection time, the need of blood transfusion, ICU, and hospital stay as well as postoperative complications and mortality.
                Both groups were comparable regarding demographics, ASA score, type of hepatectomy, duration of inflow occlusion (range, 30-75 minutes), and resection surface. The transection-related blood loss was 146 versus 250 mL (P = 0.008), and when standardized to the resection surface 1.2 versus 1.8 mL/cm (P = 0.01) for IP and IC, respectively. Although peak AST, AUCAST, and AUCALT were lower for IC, the differences did not reach statistical significance. Overall (42% vs. 38%) and major (33 vs. 27%) postoperative complications as well as median ICU (1 vs. 1 day) and hospital stay (10 vs. 11 days) were similar between both groups.
                Both IP and IC appear to be equally effective in protecting against postoperative liver injury in noncirrhotic patients undergoing major liver resection. However, IP is associated with lower blood loss and shorter transection time. Therefore, both strategies can be recommended for noncirrhotic patients undergoing liver resection. The authors compared operative course of patients undergoing major liver resections under portal triad clamping (PTC) or under hepatic vascular exclusion (HVE).
                Reduced blood loss during liver resection is achieved by PTC or HVE. Specific complications and postoperative hepatocellular injury mediated with two procedures have not been compared.
                Fifty-two noncirrhotic patients undergoing major liver resections were included in a prospective randomized study comparing both the intraoperative and postoperative courses under PTC (n = 24) or under HVE (n = 28).
                The two groups were similar at entry, but eight patients were crossed over to the other group during resection. In the HVE group, hemodynamic intolerance occurred in four (14%) patients. In the PTC group, pedicular clamping was not efficient in four patients, including three with involvement of the cavohepatic intersection and one with persistent bleeding due to tricuspid insufficiency. Intraoperative blood losses and postoperative enzyme level reflecting hepatocellular injury were similar in the two groups. Mean operative duration and mean clampage duration were significantly increased after HVE. Postoperative abdominal collections and pulmonary complications were 2.5-fold higher after HVE but without statistical significance, whereas the mean length of postoperative hospital stay was longer after HVE.
                This study shows that both methods of vascular occlusion are equally effective in reducing blood loss in major liver resections. The HVE is associated with unpredictable hemodynamic intolerance, increased postoperative complications with a longer hospital stay, and should be restricted to lesions involving the cavo-hepatic intersection. It has been shown that hepatic pedicle clamping is a safe and effective technique to control bleeding during liver resection. A major drawback can be the induction of liver ischemia and splanchnic venous stasis.
                This randomized controlled clinical trial compared continuous and intermittent hepatic pedicle clamping during resection of the cirrhotic liver in order to determine which technique is more effective in reducing operative blood loss and producing less ischemic injury. In 18 patients we performed continuous portal triad clamping during liver transection while in 17 patients we performed intermittent clamping. The two groups matched for extent of resection. Serial hepatic function tests were performed on postoperative day 1, 3 and 7.
                No significant difference was found between the two groups in terms of operative findings. Operative mortality was 5.7% (2 patients). Six patients (17.3%) had postoperative complications. There were no significant differences between the two groups with regard to postoperative liver function tests and coagulation profile.
                Continuous and intermittent clamping are both effective in reducing blood loss during hepatectomy in cirrhosis. The two techniques seem to be comparable in terms of ischemic injury. Our findings suggest that intermittent portal triad clamping may not be necessary. As this is contrary to the normal expectancy, additional studies may be needed. Intermittent occlusion of hepatic blood inflow by means of a hemihepatic or total hepatic occlusion technique is essential for reducing operative blood loss. Central liver resection to preserve more functioning liver parenchyma is mandatory for centrally located liver tumors in patients with cirrhosis, but it requires a longer overall hepatic ischemic time because of a wide transection plane. No controlled comparison has been performed for the 2 techniques in these operations.
                Hemihepatic inflow occlusion may be beneficial in cirrhotic patients who undergo complex central hepatectomy with a wide liver transection plane.
                A prospective, randomized study.
                University hospital and tertiary referral center.
                During liver parenchymal transection, 58 cirrhotic patients who underwent complex central liver resections with a wide transection plane were prospectively randomized into 2 groups. In the group undergoing total hepatic inflow clamping (group T; n = 28), occlusion of hepatic blood inflow was performed for 15 minutes with declamping for 5 minutes. In the group undergoing selective clamping of ipsilateral blood inflow (group H; n = 30), clamping was performed for 30 minutes with declamping for 5 minutes.
                Comparison of patient backgrounds, operative procedures, and early postoperative results.
                Operative blood loss, need for blood transfusion, and postoperative morbidity.
                The patients' backgrounds, operative procedures, and area of liver transection plane were not significantly different between the 2 groups. In all patients, the liver transection areas were greater than 60 cm(2) and overall liver ischemic times were greater than 60 minutes. The amount of operative blood loss and incidence of blood transfusion were significantly greater in group T because of greater blood loss during declamping. Overall liver ischemic and total operative times, postoperative morbidity, and postoperative changes in liver enzyme levels were not significantly different between groups. No in-hospital deaths occurred in either group.
                Intermittent hemihepatic and total occlusion of hepatic blood inflow are safe in cirrhotic patients with an overall ischemic time of greater than 60 minutes. However, for complex liver resections with an estimated liver transection plane of greater than 60 cm(2), hemihepatic occlusion of blood inflow, if feasible, may be recommended in cirrhotic patients to reduce operative blood loss and the incidence of blood transfusion under our defined occlusion time. 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.
                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.
                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.
                Although both techniques showed comparable efficacy for short ischemic times, intermittent vascular occlusion provided better cytoprotection when ischemia exceeded 40 minutes. The authors compared the intra- and postoperative course of patients undergoing liver resections under continuous pedicular clamping (CPC) or intermittent pedicular clamping (IPC).
                Reduced blood loss during liver resection is achieved by pedicular clamping. There is controversy about the benefits of IPC over CPC in humans in terms of hepatocellular injury and blood loss control in normal and abnormal liver parenchyma.
                Eighty-six patients undergoing liver resections were included in a prospective randomized study comparing the intra- and postoperative course under CPC (n = 42) or IPC (n = 44) with periods of 15 minutes of clamping and 5 minutes of unclamping. The data were further analyzed according to the presence (steatosis >20% and chronic liver disease) or absence of abnormal liver parenchyma.
                The two groups of patients were similar in terms of age, sex, nature of the liver tumors, results of preoperative assessment, proportion of patients undergoing major or minor hepatectomy, and nature of nontumorous liver parenchyma. Intraoperative blood loss during liver transsection was significantly higher in the IPC group. In the CPC group, postoperative liver enzymes and serum bilirubin levels were significantly higher in the subgroup of patients with abnormal liver parenchyma. Major postoperative deterioration of liver function occurred in four patients with abnormal liver parenchyma, with two postoperative deaths. All of them were in the CPC group.
                This clinical controlled study clearly demonstrated the better parenchymal tolerance to IPC over CPC, especially in patients with abnormal liver parenchyma. The optimal duration of hepatic vascular inflow occlusion (Pringle maneuver) and reperfusion during liver resection are not defined. The aim of this study was to describe the changes that occur in liver tissue pH, partial pressure of carbon dioxide (P(L)CO(2)), and partial pressure of oxygen (P(L)O(2)) and by using the P(L)CO(2) as a predictor of hepatocellular damage define the optimal clamp/release regime for intermittent portal clamping during liver resection.
                Continuous pH, P(L)CO(2), and P(L)O(2) measurements were obtained using a Paratrend multi-parameter sensor (Diametrics Medical Inc., Roseville, MN) in 13 patients undergoing elective partial liver resection. Patients were randomly allocated to undergo a 10-min clamp/5-min release regime (group 1) or a 20-min clamp/10-min release regime (group 2).
                In group 1 (n = 6) P(L)CO(2) increased and pH decreased significantly after 10 min of clamping and returned to baseline within 5 min of reperfusion. In group 2 (n = 7) the P(L)CO(2) increased and pH decreased significantly after 10 min of clamping, with a further significant change after 20 min. Following 10 min of reperfusion, pH and P(L)CO(2) had not returned to baseline. P(L)O(2) did not change significantly with either intermittent portal clamping regime.
                A reperfusion of 5 min is sufficient to restore the P(L)CO(2) and liver tissue pH to normal after 10 min of clamping, but more than 10 min of reperfusion is required after 20 min of clamping. To minimize hepatic ischemia during liver resection, a 10-min clamp/5-min release regime should be used. Clamping of the portal triad (Pringle maneuver) prevents blood loss during liver resection, but leads to liver injury upon reperfusion. Ischemic preconditioning (IP) has been shown to protect the liver against prolonged ischemic injury in animal models. However, the clinical value of this procedure has not yet been established.
                61 Patients undergoing hepatic resection under inflow occlusion were randomized to either to receive (Group-A n = 30) or not to receive (Group-B n = 31) an IP (10 minutes of ischemia followed 10 minutes of reperfusion).
                Mean (+/- SD)/ Group-A vs. Group-B. Pringle time of 34 +/- 14 and 33 +/- 12 minutes and the extent of resected liver tissue (2.7 +/- 1.3 vs. 2.7 +/- 1.1 segments) were comparable in both groups. Complications, including death, severe liver dysfunction and biliary leakage occurred in 6 patients of Group-A vs. 14 patients of Group-B (p<0.05). Intraoperative blood loss was significantly lower in Group-A (1.28 +/- 0.91 l vs. 1.94 +/- 0.76 l; p<0.001) with 5 vs. 15 patients requiring transfusions (p<0.01). In a multivariate analysis the duration of the Pringle maneuver (p<0.05) and the absence of preconditioning (p<0.05) were independent predictors for the occurrence of postoperative complications.
                IP protects against reperfusion injury, reduces the incidence of complications after hepatic resection under inflow occlusion and is simple to use in clinical practice. Two randomized prospective studies suggested that ischemic preconditioning (IP) protects the human liver against ischemia-reperfusion injury after hepatectomy performed under continuous clamping of the portal triad. The primary goal of this study was to determine whether IP protects the human liver against ischemia-reperfusion injury after hepatectomy under continuous vascular exclusion with preservation of the caval flow.
                Sixty patients were randomly divided into two groups: with (n=30; preconditioning group) and without (n=30; control group) IP (10 minutes of portal triad clamping and 10 minutes of reperfusion) before major hepatectomy under vascular exclusion of the liver preserving the caval flow. Serum concentrations of aspartate transferase, alanine transferase, glutathione-S-transferase, and bilirubin and prothrombin time were regularly determined until discharge and at 1 month. Morbidity and mortality were determined in both groups.
                Peak postoperative concentrations of aspartate transferase were similar in the groups with and without IP (851 +/- 1,733 IU/L and 427 +/- 166 IU/L respectively, p=0.2). A similar trend toward a higher peak concentration of alanine transferase and glutathione-S-transferase was indeed observed in the preconditioning group compared with the control group. Morbidity and mortality rates and lengths of ICU and hospitalization stays were similar in both groups.
                IP does not improve liver tolerance to ischemia-reperfusion after hepatectomy under vascular exclusion of the liver with preservation of the caval flow. This maneuver does not improve postoperative liver function and does not affect morbidity or mortality rates. The clinical use of IP through 10 minutes of warm ischemia in this technique of hepatectomy is not currently recommended.
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.