Reuters Health Information (2011-01-04): In liver surgery, 30-min ischemic intervals no worse than 15-min intervals
In liver surgery, 30-min ischemic intervals no worse than 15-min intervals
Last Updated: 2011-01-04 10:33:28 -0400 (Reuters Health)
NEW YORK (Reuters Health) - When surgeons need to occlude hepatic blood flow, intermittent ischemic periods can be extended to 30 minutes (as opposed to 15 minutes) without worsening hepatocellular injury, according to results from a randomized trial.
Remnant liver function was no worse after the longer ischemic intervals even though the research team used a particularly sensitive marker of hepatocyte damage.
The Dutch investigators enrolled only patients whose surgeons decided in the operating room that the "Pringle maneuver" was required. In other words, the patients needed to have blood flow to the liver completely occluded, which is accomplished by clamping the hepatoduodenal ligament. Intermittent clamping allows for better remnant function compared to continuous clamping, but the optimal duration of the ischemic intervals isn't clear.
The current study was novel because instead of using alanine and aspartate aminotransferases to assess remnant function, it used a more sensitive marker of liver damage called liver fatty acid-binding protein (L-FABP), senior author Dr. Cornelis H.C. Dejong of Maastricht University Medical Center told Reuters Health by e-mail.
It also showed for the first time that liver damage is already occurring quite early in the surgery, as the liver is being freed from its ligamentous attachments to the diaphragm, Dr. Dejong said.
The study involved 20 patients randomized to either 15- or 30-min ischemic intervals, plus 10 controls who had similar operations but did not require intermittent inflow occlusion. Each ischemic period was followed by five minutes of reperfusion. In 26 cases, the patients had liver metastases from colorectal cancer.
Cumulative ischemia times were statistically similar in the two study groups, at an average of 34 min in the 15-min group (range, 28 to 105) and 51 min in the 30-min group (range, 30 to 65), Dr. Dejong and colleagues report in the December 10th online issue of The Journal of Hepatology.
Aminotransferases did not differ significantly between two groups at any time point. L-FABP levels climbed to 1853 ng/mL in the 15-min group and 3662 ng/mL in the 30-min group after transection of the liver; levels in both groups fell rapidly from then on. There were no significant differences between the groups in cumulative L-FABP level or L-FABP level at any time point, according to the authors.
Nor were there any differences in postoperative course - need for transfusions, remnant liver function and major complications - between the intermittent occlusion groups and controls.
Nevertheless, the research teams points out that because a 2008 meta-analysis "showed no definite advantage of any form of portal triad clamping in terms of postoperative outcomes," intermittent Pringle maneuvers should be reserved for complex resections in which high blood loss is expected.
J Hepatol 2010.