Hepatic vascular occlusion methods, mostly the PM, are still frequently used by surgeons to control bleeding during liver resection and to decrease perioperative blood transfusion20,21,22,23. However, some studies have revealed that liver resection can be performed safely without using the PM11,12. Excessive intraoperative bleeding and vascular occlusion are both associated with an increased risk of postoperative morbidity and mortality. Therefore, best liver resection outcomes can be achieved when an operation is performed without hepatic vascular occlusion but with minimal blood loss and no blood transfusion. Today, with remarkable advances in surgical techniques and instruments, along with optimized anesthesia and intraoperative hemodynamic support, excellent outcomes have been achieved following liver resection without vascular clamping in high volume centers11,12. Nevertheless, the rates of laparoscopic and robotic major liver resections have increased, and controlling blood loss during these minimally invasive surgeries is difficult; to address this, several studies have recently been published to introduce different methods of the PM in laparoscopic or robotic surgeries16,17,18. In addition, the risk of intraoperative bleeding, perioperative blood infusion, postoperative complications, and mortality after EH are still considerable5,24,25.
Excessive intraoperative bleeding is inevitable in some patients who undergo EH. Therefore, it was hypothesized that reducing blood loss and preventing blood transfusion using the PM may outweigh the disadvantages of this method in patients who undergo EH. To test this hypothesis, the patient outcome after resection of ≥ five liver segments using the PM was investigated.
The results of the present study revealed that patients who underwent EH with the PM had significantly lower intraoperative bleeding and received less intraoperative RBC/FFP transfusion. Furthermore, the rate of excessive intraoperative bleeding was lower in the PM group. The hepatectomy was performed using staplers in about 70% of patients, and stapled hepatectomy was associated with a lower rate of excessive intraoperative bleeding. Similar to our findings, recent randomized-controlled trials have demonstrated that blood loss was lower during stapler hepatectomy compared with blood loss during other liver resection methods26,27,28. This indicates that the PM together with stapler hepatectomy may decrease intraoperative blood loss and prevent intraoperative blood transfusion. Additionally, patients in the PM group had significantly lower PHH, which reflects the reduced need for postoperative transfusion compared with patients in the without PM group. Perioperative blood transfusion has increased the length of hospital stay, worsened postoperative outcomes, and increased morbidity in liver resection patients29,30.
The PM can have negative effects, such as hepatic ischemia-reperfusion injury, spontaneous spleen rupture, and portal vein embolism31. In the present collective of EH patients, spleen rupture and portal vein embolism were not observed in patients after the PM. This indicates that the PM is a safe procedure, especially when it is performed quickly. The central venous pressure was always kept below 5 mmHg during the operation, which may have helped prevent intraoperative bleeding32. To assess the adverse clinical effects of ischemia-reperfusion injury, the rate of PHLF between the two groups was compared and no differences were observed. This shows that ischemia-reperfusion injury caused by a short PM does not lead to clinically significant liver damage and PHLF. Patients who were operated with the PM also had a significantly shorter ICU stay and lower rate of major morbidity compared with those who were operated without the PM. This can be explained by less intraoperative bleeding, blood transfusion, and PHH29,30. Although the PM did not significantly affect hospital stay and mortality, a longer ICU stay and higher rate of major morbidity are associated with higher costs and an increased need for intervention or reoperation33.
From an oncological point of view, there was no significant difference in 3-year recurrence rate between the two groups. These findings are in line with those of recent studies, which demonstrated that the PM does not affect recurrence after hepatectomy for both primary34,35 and secondary liver malignancies36,37. Some studies have shown that prolonged PM may be associated with recurrence after hepatocellular carcinoma38 and colorectal liver cancer metastasis39, but a fast PM does not increase the risk. The median duration of the PM in the present study was less than 20 minutes. Conversely, blood loss during hepatectomy and subsequent perioperative blood transfusion has been associated with poor overall and disease-free survival in hepatocellular carcinoma patients35,40. Therefore, not only does a shorter PM not increase the recurrence rate but it may even reduce it by preventing excessive blood loss and need for a blood transfusion.
Results of a European survey on the application of vascular control in liver surgery revealed that excessive blood loss, major hepatectomy, non-anatomical resections, and proximity to large vessels or bile ducts were common indications for vascular clamping during liver resection41. Deciding to perform the PM during hepatectomy should be based on an individual bleeding risk assessment and operation technique and difficulties. Indeed, because the liver is more vulnerable to bleeding than to ischemia29,30,31,35, the PM should be considered for procedures with a high risk of excessive intraoperative bleeding, such as EH. However, the PM should be performed as quickly as possible to prevent clinically significant liver damage due to ischemia-reperfusion injury. The liver can tolerate a continuous inflow occlusion of up to 120 minutes42. Therefore, clamping to prevent bleeding during EH is worthwhile, but should be done as quickly as possible.
The non-randomized design is a limitation of the present study because of possible selection bias. However, as mentioned above, the decision to perform the PM was based on the surgeons’ preference and was not influenced by patient-related factors. Additionally, to minimize potential bias and estimate the independent effect of the PM on posthepatectomy outcome, PS analysis was performed and factors that may affect the outcomes were controlled.
In conclusion, performing the PM is justified during EH because an EH has a high risk of excessive intraoperative bleeding. The PM decreases intraoperative blood loss and transfusion, reduces PHH and major morbidity, shortens the ICU stay, and does not affect long-term recurrence after EH. Of course, the duration of PM should be kept as short as possible. Randomized-controlled trials are necessary to draw robust conclusions regarding the use of the PM during EH.