Vascular occlusion in hepatic resections in cirrhotic rat livers: an experimental study in rats

Methods to decrease blood loss during liver resection: a network meta-analysis

BACKGROUND

Liver resection is a major surgery with significant mortality and morbidity. Specialists have tested various methods in attempts to limit blood loss, transfusion requirements, and morbidity during elective liver resection. These methods include different approaches (anterior versus conventional approach), use of autologous blood donation, cardiopulmonary interventions such as hypoventilation, low central venous pressure, different methods of parenchymal transection, different methods of management of the raw surface of the liver, different methods of vascular occlusion, and different pharmacological interventions. A surgeon typically uses only one of the methods from each of these seven categories. The optimal method to decrease blood loss and transfusion requirements in people undergoing liver resection is unknown.

OBJECTIVES

To assess the effects of different interventions for decreasing blood loss and blood transfusion requirements during elective liver resection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and Science Citation Index Expanded to September 2015 to identify randomised clinical trials. We also searched trial registers and handsearched the references lists of identified trials.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or publication status) comparing different methods of decreasing blood loss and blood transfusion requirements in people undergoing liver resection.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified trials and collected data. We assessed the risk of bias using Cochrane domains. We conducted a Bayesian network meta-analysis using the Markov chain Monte Carlo method in WinBUGS 1.4, following the guidelines of the National Institute for Health and Care Excellence Decision Support Unit guidance documents. We calculated the odds ratios (OR) with 95% credible intervals (CrI) for the binary outcomes, mean differences (MD) with 95% CrI for continuous outcomes, and rate ratios with 95% CrI for count outcomes, using a fixed-effect model or random-effects model according to model-fit. We assessed the evidence with GRADE.

MAIN RESULTS

We identified 67 randomised clinical trials involving a total of 6197 participants. All the trials were at high risk of bias. A total of 5771 participants from 64 trials provided data for one or more outcomes included in this review. There was no evidence of differences in most of the comparisons, and where there was, these differences were in single trials, mostly of small sample size. We summarise only the evidence that was available in more than one trial below. Of the primary outcomes, the only one with evidence of a difference from more than one trial under the pair-wise comparison was in the number of adverse events (complications), which was higher with radiofrequency dissecting sealer than with the clamp-crush method (rate ratio 1.85, 95% CrI 1.07 to 3.26; 250 participants; 3 studies; very low-quality evidence). Among the secondary outcomes, the only differences we found from more than one trial under the pair-wise comparison were the following: blood transfusion (proportion) was higher in the low central venous pressure group than in the acute normovolemic haemodilution plus low central venous pressure group (OR 3.19, 95% CrI 1.56 to 6.95; 208 participants; 2 studies; low-quality evidence); blood transfusion quantity (red blood cells) was lower in the fibrin sealant group than in the control (MD -0.53 units, 95% CrI -1.00 to -0.07; 122 participants; 2; very low-quality evidence); blood transfusion quantity (fresh frozen plasma) was higher in the oxidised cellulose group than in the fibrin sealant group (MD 0.53 units, 95% CrI 0.36 to 0.71; 80 participants; 2 studies; very low-quality evidence); blood loss (MD -0.34 L, 95% CrI -0.46 to -0.22; 237 participants; 4 studies; very low-quality evidence), total hospital stay (MD -2.42 days, 95% CrI -3.91 to -0.94; 197 participants; 3 studies; very low-quality evidence), and operating time (MD -15.32 minutes, 95% CrI -29.03 to -1.69; 192 participants; 4 studies; very low-quality evidence) were lower with low central venous pressure than with control. For the other comparisons, the evidence for difference was either based on single small trials or there was no evidence of differences. None of the trials reported health-related quality of life or time needed to return to work.

AUTHORS' CONCLUSIONS

Paucity of data meant that we could not assess transitivity assumptions and inconsistency for most analyses. When direct and indirect comparisons were available, network meta-analysis provided additional effect estimates for comparisons where there were no direct comparisons. However, the paucity of data decreases the confidence in the results of the network meta-analysis. Low-quality evidence suggests that liver resection using a radiofrequency dissecting sealer may be associated with more adverse events than with the clamp-crush method. Low-quality evidence also suggests that the proportion of people requiring a blood transfusion is higher with low central venous pressure than with acute normovolemic haemodilution plus low central venous pressure; very low-quality evidence suggests that blood transfusion quantity (red blood cells) was lower with fibrin sealant than control; blood transfusion quantity (fresh frozen plasma) was higher with oxidised cellulose than with fibrin sealant; and blood loss, total hospital stay, and operating time were lower with low central venous pressure than with control. There is no evidence to suggest that using special equipment for liver resection is of any benefit in decreasing the mortality, morbidity, or blood transfusion requirements (very low-quality evidence). Radiofrequency dissecting sealer should not be used outside the clinical trial setting since there is low-quality evidence for increased harm without any evidence of benefits. In addition, it should be noted that the sample size was small and the credible intervals were wide, and we cannot rule out considerable benefit or harm with a specific method of liver resection.

Volatile anesthetics might be more beneficial than propofol for postoperative liver function in cirrhotic patients receiving hepatectomy

Hepatic inflow occlusion during the liver surgery may result in a transient ischemia period followed by reperfusion, and may initiate liver injury and lead to postoperative liver dysfunction. Especially in cirrhotic patients, the tolerance time of ischemia is much shorter and the outcome would be worse. Recently, clinical trials had proved that volatile anesthetics rather than propofol can protect myocardial cells from ischemia reperfusion (IR) injury in cardiac surgery. Meanwhile, animal studies had revealed that volatile anesthetics could induce some endogenous protective molecules in the liver such as hypoxia induced factor-1 (HIF-1), heme oxygenase (HO) enzyme system and inducible nitric oxide synthase (iNOS), which make the volatile anesthetics posing the extraordinary anti-oxidative, anti-inflammatory, anti-apoptotic, and vasodilatory characteristics. However, there is still lack of trials to compare the postoperative outcomes such as liver function in cirrhotic patients undergoing liver surgery with inflow occlusion between volatile anesthetics and propofol anesthesia. Hence we hypothesize that with its anti-IR injury characteristics, volatile anesthetics might be the more appropriate choice in cirrhotic patients undergoing liver surgery with occlusion.

Additional value of FDG-PET/CT in management of "solitary" liver metastases: preliminary results of a prospective multicenter study

BACKGROUND AND AIM

The most common malignancy affecting the liver is metastasis from a wide variety of tumors, particularly those of gastrointestinal origin. Successful surgical removal of a solitary liver metastasis may significantly extend survival and optimal preoperative assessment in this regard is a mandatory prerequisite for proper patient selection. The addition of positron emission tomography/computed tomography (PET/CT) to other more conventional imaging procedures (e.g., ultrasound (US), CT, and magnetic resonance) has the potential to greatly improve the selection process by the combination of high-resolution anatomy afforded by CT directly combined with the functional scintigraphic map of intra- and extrahepatic lesions depicted by 2-deoxy-2-[F-18]fluoro-D-glucose (FDG)-PET. In this study, we assess the additional value of PET/CT in the management strategy of patients with solitary liver metastasis from colorectal and other cancers identified by conventional imaging methods.

METHODS

We evaluated 43 consecutive patients (17 males, 26 females, mean age 53 +/- 6 years) with known solitary liver metastasis. This sample consisted of 18 patients with colorectal cancer, 15 with nonsmall cell lung cancer, six with breast carcinoma, and four ovarian cancers. In addition to contrast-enhanced CT and US, all patients were studied with FDG-PET/CT before surgery. PET/CT was performed within 3 weeks of the initial diagnosis and the scans were read by two experienced radiologists/nuclear medicine specialists blinded to the clinical data. A final diagnosis was obtained at surgery in 31 patients, by fine needle biopsy in five, and long-term clinical, biochemical, and follow-up imaging in seven patients.

RESULTS

In 12 out of 43 patients (28%), PET/CT resulted in restaging disease and a change in therapy. Twenty-two of 31 patients with confirmed solitary liver lesions (71%) were disease-free, eight of 31 (26%) developed a new recurrence, and one of 31 (3%) died from disease progression over a 17 +/- 6-month follow-up interval. Nine of 12 patients (75%) with multiple metastases demonstrated by FDG-PET/CT were alive with disease and three of 12 (25%) deceased due to disease progression (p < 0.01) over a 17 +/- 6-month follow-up interval.

CONCLUSION

The addition of FDG-PET/CT to the routine assessment of patients with liver metastasis has a significant impact on disease staging and selection of suitable candidates for solitary liver metastasis resection and outcome.

Heme oxygenase-1 induction by hemin protects liver cells from ischemia/reperfusion injury in cirrhotic rats

AIM: To investigate the potential protective effect of HO-1 on cirrhotic liver cells in rats.

METHODS: Male Wistar rats included in the current study were randomly divided into 5 groups as follows: normal (N) group; liver cirrhotic (LC) group; sham (S) group; I/R group and I/R + hemin group. The model for inducing liver cirrhosis in rats was established according to a previously published protocol. Following this the segmental hepatic ischemia reperfusion operation was carried out. The rats were treated with 30 μmol/kg hemin (HO-1 inducer, ferric protoporphyrin IX chloride) i.p. or 0.9% NaCl (control) 24 h and 12 h before hepatic ischemia for 30 min or sham laparotomy. Blood was collected for serum enzymatic measurement 6 and 12 h after reperfusion or sham laparotomy. HO-1, NF-κB and caspase-3 expressions were assessed by immunohistochemical analysis.

RESULTS: The expressions of proteins are inversely correlated to the gray values. HO-1 expression in the I/R + hemin group was increased significantly than I/R group at 6 h and 12 h after hepatic I/R (6 h: 112.0 ± 8.3 vs 125.1 ± 5.7, P < 0.01; 12 h: 120.8 ± 11.0 vs 132.4 ± 6.2, P < 0.01). Hemin improved serum manganese superoxide dismutase (MnSOD) (6 h: 131.3 ± 17.6 vs 107.0 ± 13.9, P < 0.01; 12 h: 141.4 ± 12.5 vs 118.3 ± 10.2, P < 0.01), lessened liver cell injury, decreased caspase-3(6 h: 166.7 ± 8.1 vs 145.5 ± 14.6, P < 0.01; 12 h: 172.8 ± 3.8 vs 148.0 ± 6.5, P < 0.01) and NF-κB expression (6 h: 150.2 ± 8.6 vs 139.7 ± 6.0, P < 0.01; 12 h: 151.1 ± 5.9 vs 148.1 ± 5.3, P > 0.05) and serum alanine aminotransferase (ALT) (6 h: 413.3 ± 104.1 vs 626.8 ± 208.2, P < 0.01; 12 h: 322.2 ± 98.8 vs 425.8 ± 115.4, P < 0.05), aspartate aminotransferase (AST) (6 h: 665.2 ± 70.1 vs 864.3 ± 70.4, P < 0.01; 12 h: 531.1 ± 98.6 vs 664.4 ± 115.6, P < 0.01), malondialdehyde (MDA) levels (6 h: 11.1 ± 2.17 vs 13.5 ± 2.01, P < 0.01; 12 h: 9.36 ± 1.10 vs 10.8 ± 1.62, P < 0.05) in the I/R + hemin group when compared with the I/R group.

CONCLUSION: These results suggest that HO-1 plays an important role in protecting liver cells from hepatic I/R injury in cirrhotic rats by decreasing oxidative stress, apoptosis and inflammation.

Does the novel PET/CT imaging modality impact on the treatment of patients with metastatic colorectal cancer of the liver?

OBJECTIVE

To compare the diagnostic value of contrast-enhanced CT (ceCT) and 2-[18-F]-fluoro-2-deoxyglucose-PET/CT in patients with metastatic colorectal cancer to the liver.

BACKGROUND

Despite preoperative evaluation with ceCT, the tumor load in patients with metastatic colorectal cancer to the liver is often underestimated. Positron emission tomography (PET) has been used in combination with the ceCT to improve identification of intra- and extrahepatic tumors in these patients. We compared ceCT and a novel fused PET/CT technique in patients evaluated for liver resection for metastatic colorectal cancer.

METHODS

Patients evaluated for resection of liver metastases from colorectal cancer were entered into a prospective database. Each patient received a ceCT and a PET/CT, and both examinations were evaluated independently by a radiologist/nuclear medicine physician without the knowledge of the results of other diagnostic techniques. The sensitivity and the specificity of both tests regarding the detection of intrahepatic tumor load, extra/hepatic metastases, and local recurrence at the colorectal site were determined. The main end point of the study was to assess the impact of the PET/CT findings on the therapeutic strategy.

RESULTS

Seventy-six patients with a median age of 63 years were included in the study. ceCT and PET/CT provided comparable findings for the detection of intrahepatic metastases with a sensitivity of 95% and 91%, respectively. However, PET/CT was superior in establishing the diagnosis of intrahepatic recurrences in patients with prior hepatectomy (specificity 50% vs. 100%, P = 0.04). Local recurrences at the primary colo-rectal resection site were detected by ceCT and PET/CT with a sensitivity of 53% and 93%, respectively (P = 0.03). Extrahepatic disease was missed in the ceCT in one third of the cases (sensitivity 64%), whereas PET/CT failed to detect extrahepatic lesions in only 11% of the cases (sensitivity 89%) (P = 0.02). New findings in the PET/CT resulted in a change in the therapeutic strategy in 21% of the patients.

CONCLUSION

PET/CT and ceCT provide similar information regarding hepatic metastases of colorectal cancer, whereas PET/CT is superior to ceCT for the detection of recurrent intrahepatic tumors after hepatectomy, extrahepatic metastases, and local recurrence at the site of the initial colorectal surgery. We now routinely perform PET/CT on all patients being evaluated for liver resection for metastatic colorectal cancer.