Conceived and designed the experiments: SAWGD KWR CHCD. Performed the experiments: SAWGD KWR. Analyzed the data: SAWGD KWR CHCD MP MAJvdB RMvD MHAB THvK SWMOD. Contributed reagents/materials/analysis tools: WB CHCD THvK. Wrote the paper: SAWGD KWR CHCD MP WAB SWMOD.
The authors have declared that no competing interests exist.
The intermittent Pringle maneuver (IPM) is frequently applied to minimize blood loss during liver transection. Clamping the hepatoduodenal ligament blocks the hepatic inflow, which leads to a non circulating (hepato)splanchnic outflow. Also, IPM blocks the mesenteric venous drainage (as well as the splenic drainage) with raising pressure in the microvascular network of the intestinal structures. It is unknown whether the IPM is harmful to the gut. The aim was to investigate intestinal epithelial cell damage reflected by circulating intestinal fatty acid binding protein levels (I-FABP) in patients undergoing liver resection with IPM.
Patients who underwent liver surgery received total IPM (total-IPM) or selective IPM (sel-IPM). A selective IPM was performed by selectively clamping the right portal pedicle. Patients without IPM served as controls (no-IPM). Arterial blood samples were taken immediately after incision, ischemia and reperfusion of the liver, transection, 8 hours after start of surgery and on the first post-operative day.
24 patients (13 males) were included. 7 patients received cycles of 15 minutes and 5 patients received cycles of 30 minutes of hepatic inflow occlusion. 6 patients received cycles of 15 minutes selective hepatic occlusion and 6 patients underwent surgery without inflow occlusion. Application of total-IPM resulted in a significant increase in I-FABP 8 hours after start of surgery compared to baseline (
Total-IPM in patients undergoing liver resection is associated with a substantial increase in arterial I-FABP, pointing to intestinal epithelial injury during liver surgery.
ClinicalTrials.gov
Intra-operative blood loss and red blood cell transfusions are associated with short- and long-term complications in liver surgery, such as operative mortality or major complications that require post-operative radiologic or surgical intervention
IPM may have a negative effect on outcome after liver resection as a consequence of liver injury due to ischemia reperfusion (I/R) damage
Intestinal fatty acid binding protein (I-FABP) is a small, water-soluble cytosolic protein that is easily released into the circulation upon enterocyte membrane integrity loss. I-FABP is solely present in mature epithelial cells of the small intestine and to a lesser extent in the large intestine
The principal aim of this study was to investigate whether IPM causes intestinal epithelial cell damage and barrier loss in patients undergoing liver resection.
Patients who underwent liver surgery at Maastricht University Medical Center were eligible for inclusion in this prospective trial. The study was approved by the medical ethical committee of Maastricht University Medical Center and conducted according to the revised version of the Declaration of Helsinki (October 2008, Seoul). All patients gave written informed consent.
Pre-operatively it was decided whether a Pringle maneuver was required according to the surgeon's preference. If a Pringle maneuver was required, patients were randomly assigned to IPM with 15 (15-IPM) or 30 minutes (30-IPM) ischemic intervals. Patients who did not require IPM served as controls (no-IPM). These patients were investigated in an RCT on a different topic by our group in the recent past
Pre-operatively, all patients had radial artery and central venous catheters inserted to monitor arterial and central venous pressure as part of standard anesthetic care. Liver resection was performed as detailed elsewhere
Arterial blood samples were obtained from the radial artery line at predefined time points (
I-FABP is a highly sensitive and specific marker of intestinal epithelial cell damage
In order to measure the source and fate of I-FABP, blood was also drawn from the portal vein and hepatic vein after liver transection in the no-IPM and total-IPM group (T = 4,
AV-difference gut = portal venous [I-FABP]−arterial [I-FABP]
Hepatosplanchnic AV-difference = hepatovenous [I-FABP]−arterial [I-FABP].
IgG Endotoxin Core Antibodies were used to quantify endotoxemia. A drop from pre-operative values to post-operative values was interpreted as consumption of antibodies to endotoxin by systemic release of endotoxin. IgG EndoCAb was measured using a commercially available enzyme-linked immunosorbent assay (ELISA), kindly provided by Hycult Biotechnology, Uden, the Netherlands (range: 0.13–8.00 GMU/ml). EndoCAb data are expressed in General Median Units (GMU)/ml. General Median Units of IgG are arbitrary and are based on medians of healthy adults, with 100 GMU/ml being the median.
Mann Whitney
Twenty-four patients (11 females; 13 males) scheduled for hepatectomy for primary (n = 2) or secondary malignant liver tumours (n = 22) were included. Thirteen patients underwent major liver resections (≥3 segments) and eleven a minor liver resection (<3 segments). The 15-IPM group received 15 minutes of ischemia (n = 7), median 2 (2–5) cycles and a cumulative total ischemia time of 33 (30–75) minutes. The 30-IPM group received 30 minutes of ischemia (n = 5), median 1 (1–2) cycle and a cumulative total ischemia time of 30 (30–56) minutes.
The sel-IPM group received selective clamping of the right portal pedicle (n = 6), and controls (no-IPM) received no vascular clamping (n = 6). There were no relevant significant differences between groups neither in baseline characteristics (
15 min total-IPM(n = 7) | 30 min total-IPM(n = 5) | No-IPM(n = 6) | Sel-IPM(n = 6) |
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Age (years) | 60.8 (48.3–79.9) | 67.3 (60.3–77.4) | 60.5 (59.6–70.1) | 64.6 (42.9–70.1) | 0.64 |
Gender | (3 F; 4 M) | (2 F; 3 M) | (1 F; 5 M) | (5 F; 1 M) | 0.14 |
Height (cm) | 1.77 (1.55–1.92) | 1.70 (1.63–1.75) | 1.76 (1.72–1.95) | 1.65 (1.60–1.86) | 0.11 |
Weight (kg) | 72 (56–100) | 74 (54–83) | 75 (68–90) | 71 (55–88) | 0.83 |
Body Mass Index | 23.2 (22.6–27.4) | 24.2 (20.3–28.7) | 23.4 (23.0–25.7) | 25.1 (19.3–30.8) | 0.70 |
Aspartate-aminotransferase (IU/L) | 33 (13–52) | 16 (7–25) | 21 (10–32) | 19 (11–26) | 0.13 |
Alanine-aminotransferase (IU/L) | 36 (11–51) | 26 (8–41) | 26 (7–55) | 23 (21–29) | 0.75 |
Lactate dehydrogenase (IU/L) | 399 (305–595) | 356 (299–432) | 319 (291–557) | 389 (316–514) | 0.55 |
Gamma-glutamyl transpeptidase (IU/L) | 56 (22–204) | 37 (32–169) | 34 (18–83) | 33 (29–63) | 0.61 |
Alkaline phosphatase (IU/L) | 134 (55–256) | 90 (66–124) | 80 (58–128) | 115 (57–126) | 0.52 |
Bilirubin (µM) | 13.8 (11.3–14.2) | 10.6 (8.3–13.0) | 14.0 (6.9–16.5) | 11.3 (7.8–12.9) | 0.15 |
Pre-operative creatinin (µmol/L) | 78 (59–125) | 92 (85–137) | 76 (54–96) | 80.5 (46–287) | 0.40 |
Data are presented as median (range). All data are preoperative values.
15 min total-IPM(n = 7) | 30 min total-IPM(n = 5) | No-IPM(n = 6) | Sel-IPM(n = 6) |
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Operation time(hours: minutes) | 3:15 h (2:10–6:30) | 4:15 h (3:09–4:45) | 3:24 h (2:20–4:10) | 3:45 h (2:27–4:30) | 0.62 |
Blood loss (ml) | 850 (250–3900) | 1000 (250–2500) | 750 (200–2600) | 1050 (400–2500) | 0.93 |
Number of resected segments | 3 (2–3) | 3(1–3) | 2 (1–3) | 3 (2–3) | 0.48 |
Post-operative creatinin (µmol/L) day 0/1 | 71 (55–114) | 110 (101–115) | 88 (52–93) | 76 (44–248) | 0.17 |
Data are presented as median (range).
Baseline (T = 1) arterial I-FABP levels did not differ significantly between groups (15-IPM, 532 pg/ml [353–1,078]; 30-IPM, 565 pg/ml [500–1,156]; sel-IPM, 874 pg/ml [478–1,198]; no-IPM, 502 pg/ml [161–966]
No significant differences between 15-IPM and 30-IPM groups in median plasma I-FABP values were found at any time point. In the 15 minutes IPM group a significant increase in I-FABP was observed from baseline (T = 1) to after transection (T = 4) (15-IPM: 532 pg/ml [353–1,078] to 891 pg/ml [392–3,053]
The 15-IPM and 30-IPM groups were subsequently pooled and compared with controls (no-IPM) since there was no significant difference in intestinal epithelial cell damage between 15-IPM and 30-IPM. In the total-IPM group, plasma I-FABP levels increased significantly from baseline to 8 hours after start of surgery (549 pg/ml [353–1,156] to 1,279 pg/ml [560–2,000],
In patients who received selective clamping of the right portal pedicle (sel-IPM), plasma I-FABP levels did not increase significantly from baseline to 8 hours after start of surgery (806 pg/ml [478–1,198] to 924 pg/ml [248–2,823],
In order to prove that I-FABP is specifically released from the gut we performed an organ balance analysis to reveal the origin of circulating I-FABP. The data show that I-FABP was specifically released from the gut after liver transection. This resulted in a net release of I-FABP from the hepatosplanchnic area (
Plasma levels of natural IgG against endotoxin were significantly decreased in the total-IPM group on post-operative day 1 (POD1) compared to baseline (baseline, 52.9 GMU/mL [10.0–112.1], POD1, 33.2 GMU/mL [10.0–89.1]
This study aimed to investigate whether IPM causes loss of intestinal epithelial cell integrity and leads to endotoxemia in patients undergoing liver resection. The results of the present study show that the use of total IPM is associated with intestinal epithelial cell damage and subsequent endotoxemia. In the total-IPM group (15 min and 30 min total IPM combined), plasma I-FABP levels were significantly increased 8 hours after start of surgery compared to baseline, while in the no-IPM group and sel-IPM group no significant differences in I-FABP levels were observed between different time points. By measuring concentration differences across the gut and the hepatosplanchnic area, we were able to show that there was a net I-FABP release from the hepatosplanchnic area in the total-IPM group, explaining the high levels of I-FABP in this group.
In the total-IPM group IgG EndoCAb decreased significantly on POD1 compared to baseline while this effect was not observed in the no-IPM and sel-IPM group. Consumption of IgG EndoCAb in the total IPM group suggests that total IPM resulted in translocation of gut derived endotoxins, possibly by intestinal barrier dysfunction due to epithelial cell damage.
The results of the present study are in line with several animal studies. Ochiai
Patients undergoing liver resection are more susceptible to development of a systemic inflammatory response due to endotoxemia, as hepatic endotoxin clearance is compromised due to a reduction of Kuppfer cells
The present study sheds new light on the question whether performing IPM is favorable in patients undergoing liver surgery. Hepatectomies without IPM can be performed safely due to advances in liver surgery such as the development of modern hemostatic devices and improvements in anesthesiological management
A possibly more safe approach than total IPM is selective IPM, which is performed by selectively excluding the right or left hemi liver from the circulation. Selectively clamping the right or left portal pedicle is safe and feasible for patients with normal liver parenchyma and especially in cirrhotic patients the selective IPM induces less ischemic liver injury compared to total IPM
The present study shows that the use of the total intermittent Pringle maneuver causes intestinal epithelial cell damage and endotoxemia during liver surgery in man. IPM can therefore potentially increase the risks of liver resections despite a possible reduction of intraoperative blood loss. Intestinal epithelial cell damage and endotoxemia induced by IPM could negatively affect the patient's condition and post-operative recovery. Whether gut damage as a consequence of the total-IPM is causally related to systemic inflammation remains to be established.
The authors thank Johanne G. Bloemen for her contribution to conception and design of the study and data collection.