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Methods of vascular occlusion for elective liver resections

  • Review
  • Intervention

Authors


Abstract

Background

Vascular occlusion is used to reduce blood loss during liver resection surgery. Various methods of vascular occlusion have been suggested.

Objectives

To compare the benefits and harms of different methods of vascular occlusion during elective liver resection.

Search methods

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.

Selection criteria

We included randomised clinical trials comparing different methods of vascular occlusion during elective liver resections (irrespective of language or publication status).

Data collection and analysis

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.

Main results

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.

Authors' conclusions

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.

摘要

背景

各種血流阻斷術用於選擇性肝臟切除

血流阻斷術用於在肝切除手術過程中降低血液流失。而建議使用的血流阻斷術有許多種方式。

目標

比較在選擇性肝臟切除過程中使用各種血流阻斷術的利弊。

搜尋策略

我們搜尋截至2008年8月The Cochrane HepatoBiliary Group Controlled Trials Register, Cochrane Library的Cochrane Central Register of Controlled Trials (CENTRAL)、MEDLINE、EMBASE和cience Citation Index Expanded。

選擇標準

我們包括比較在選擇性肝臟切除過程中使用各種血流阻斷術的隨機臨床試驗(不受語言或發表狀態的限制)。

資料收集與分析

2位作者獨立評估收錄的試驗,獨立摘錄數據。根據治療意向或已獲取的資料分析,使用固定效果和隨機效果模式,計算風險比率(risk ratio)或平均差(mean difference)及其95% 信賴區間。

主要結論

10個試驗比較各種血流阻斷術的方法,共有657位病人。 所有試驗的偏誤風險較高。每次比較我們只包括1或2個試驗。 各類比較沒有在死亡率,肝臟衰竭或其他發病率方面出現統計學上顯著差異。 肝血管閉塞沒有降低輸血要求。 減少心輸出量,增加症狀性血管阻力。在比較持續性肝門阻斷和間歇性肝門阻斷時,切除肝臟後使用持續性肝門阻斷的5個慢性肝病病人裏有4個人患有肝臟衰竭。 在比較選擇性血流阻斷和肝門阻斷時,選擇性血流阻斷組的4個病人都患有肝臟衰竭。 其他比較沒有在其他重要結果上出現差異。

作者結論

在選擇性肝臟切除術裏,建議使用肝門阻斷而不是肝血管閉塞。間歇性肝門阻斷似乎優於肝門阻斷,至少在慢性肝病的病人看來是這樣。沒有證據支持選擇性血流阻斷優於肝門阻斷。間隙性肝門阻斷的最佳做法還不明確。沒有證據指出血管閉塞之後進行缺血預處理和對病人無肝硬化症狀的肝切除實施間歇性血流阻斷術有任何的差異。需要更多偏誤風險低的隨機試驗來確定血流阻斷術的最佳方法。

翻譯人

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

需要進一步的試驗來尋找肝切除血流阻斷術的最佳方法: 每年英國將實施1000例以上的選擇性肝臟切除手術(計畫內手術)。實施肝切除時,應停止肝臟內的血液流動(血流阻斷術),這樣才能潛在降低血液的損失。在肝切除過程中應用血流阻斷的方法,一般上,應先以持續性或間歇性的方法(阻斷的時間可變,和無阻斷交替進行幾個週期之後,直到完成肝臟切除手術),這就叫做肝門阻斷。但是,這種技術有許多變動的因素,包括肝血管阻斷,另外肝動脈和門靜脈阻斷,為了更多降低血液損失,阻斷肝臟向靜脈輸送的血液;選擇性血流阻斷只有當切除血管輸血的肝臟後才能阻斷;至於缺血預處理,目的是為缺血的肝臟準備血液,簡短的實施血流阻斷術,然後再恢復血液流動(再灌注)。本次文獻回顧目的在於評估在肝臟切除中使用的各種血流阻斷術的方法。本次文獻回顧包括10個試驗,共657 位病人。所有試驗具有較高的偏誤風險(系統誤差)和較高的機率(隨機誤差)。每次比較我們只包括1或2個試驗。各類比較沒有在死亡率,肝臟衰竭或術後併發症方面出現差異。肝血流阻斷術不會降低輸血要求。減少心輸出量(每一秒鐘心臟向外輸送的血液量),增加症狀性血管阻力(阻力血管內的血液流動),這些可能是心臟病病人的潛在問題。儘管持續性肝門阻斷和間歇性肝門阻斷(5/60; 8.5% 對照0/61)沒有在肝衰竭的發病率方面具有統計上顯著差異;但是,切除肝臟後使用持續性肝門阻斷的慢性肝病的病人多數會出現肝衰竭。選擇性血液阻斷對照肝門阻斷沒有顯示有任何的益處。兩組在肝衰竭發病率方面沒有統計學意義上的顯著差異(4/41; 9.8% 對照0/39), 但是選擇性血液閉塞組的多數病人出現了肝臟衰竭。從各種間歇性肝門阻斷的方法比較來看,對非肝硬化病人切除肝臟之後實施持續性血流阻斷術和間歇性血流阻斷術,和缺血預處理比較起來,兩者均沒有在任意重要結果上顯示顯著差異。需要更多的低風險隨機試驗來確定血流阻斷術的最佳技術。

Plain language summary

Further trials are necessary to find the optimal method of vascular occlusion in liver resection

More than 1000 elective liver resections (planned operation) are performed annually in the United Kingdom alone. When liver resection is performed, the inflow of blood to the liver can be blocked (vascular occlusion), thereby potentially reducing the blood loss. When employed during liver resection, the vascular occlusion is generally achieved by occluding the hepatic artery and portal vein (blood vessels which supply the blood to the liver) either continuously or intermittently (when varying periods of occlusion and no occlusion are carried out in cycles till liver resection is complete). This is called portal triad clamping. However, there are many variations to this technique. These include hepatic vascular exclusion, where in addition to the occlusion of hepatic artery and portal vein, the veins draining blood from the liver are occluded with an intention of further decreasing the blood loss; selective inflow occlusion when only the vessels supplying the portion of the liver to be resected is occluded; and ischaemic preconditioning, where in order to prepare the liver for lack of blood flow, a vascular occlusion is performed briefly, after which the blood flow is re-established (reperfusion). This review is aimed at evaluating the different methods of vascular occlusion in liver resection.

Ten trials including 657 patients were included in this review. All were of high risk of bias (systematic error) and play of chance (random error). Only one or two trials were included under each comparison. There was no difference in mortality, liver failure, or post-operative complications between any of the comparisons. Hepatic vascular occlusion does not decrease the blood transfusion requirements. It decreases the cardiac output (amount of blood pumped by the heart in one second) and increases the systemic vascular resistance (resistance to the flow of blood in the vessels), which may have potential problems in patients with heart disorders.

Although there was no statistically significant difference in the incidence of liver failure between continuous portal triad clamping and intermittent portal triad clamping (5/60; 8.5% versus 0/61), most of them occurred in patients with chronic liver diseases undergoing the liver resections using continuous portal triad clamping.

There was no benefit in selective inflow occlusion compared to portal triad clamping. There was no statistically significant difference in the incidence of liver failure between the two groups (4/41; 9.8% versus 0/39), but all patients with liver failure occurred in the selective inflow occlusion group.

There were no significant differences in any of the important outcomes between the different methods of intermittent portal triad clamping or between ischaemic preconditioning followed by continuous vascular occlusion and intermittent vascular occlusion in non-cirrhotic patients undergoing liver resections.

Further randomised trials of low risk of bias are needed to determine the optimal technique of vascular occlusion.

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