[Small-for-size: experimental findings for liver surgery]

Spleen volume is a predictor of posthepatectomy liver failure and short-term mortality for hepatocellular carcinoma

BACKGROUND

The study aimed at retrospectively assessing the impact of spleen volume (SpV) on the development of posthepatectomy liver failure (PHLF) in patients who underwent hepatectomy for hepatocellular carcinoma (HCC).

METHODS

152 patients with primary HCC who underwent hepatectomy (sectionectomy or more) were classified into PHLF and non-PHLF groups, and then the relationship between PHLF and SpV was assessed. SpV (cm3) was obtained from preoperative CT and standardized based on the patient's body surface area (BSA, m2).

RESULTS

PHLF was observed in 39 (26%) of the 152 cases. SpV/BSA was significantly higher in the PHLF group, and the postoperative 1-year survival rate was significantly worse in the PHLF group than that in the non-PHLF group (p = 0.044). Multivariable analysis revealed SpV/BSA as a significant independent risk factor for PHLF. Using the cut-off value (160 cm3/m2), the 152 cases were divided into small SpV and large SpV groups. The incidence of PHLF was significantly higher in the large SpV group (p = 0.002), the liver failure-related mortality rate was also significantly higher in the large SpV group (p = 0.007), and the 1-year survival rate was significantly worse in the large SpV group (p = 0.035).

CONCLUSION

These results suggest SpV as a predictor of PHLF and short-term mortality in patients who underwent hepatectomy for HCC. Moreover, SpV measurement is a simple and potentially useful method for predicting PHLF in patients with HCC.

Portal hyperperfusion after major liver resection and associated sinusoidal damage is a therapeutic target to protect the remnant liver

Extended liver resection results in loss of a large fraction of the hepatic vascular bed, thereby causing abrupt alterations in perfusion of the remnant liver. Mechanisms of hemodynamic adaptation and associated changes in oxygen metabolism after liver resection and the effect of mechanical portal blood flow reduction were assessed. A pig model (n = 16) of extended partial hepatectomy was established that included continuous observation for 24 h under general anesthesia. Pigs were randomly separated into two groups, one with a portal flow reduction of 70% compared with preoperative values, and the other as a control (n = 8, each). In controls, portal flow [mean (SD)] increased from 74 (8) mL·min^-1·100 g^-1 preoperatively to 240 (48) mL·min^-1·100 g^-1 at 6 h after resection (P < 0.001). Hepatic arterial buffer response was abolished after resection. Oxygen uptake per unit liver mass increased from 4.0 (1.1) mL·min^-1·100 g^-1 preoperatively to 7.7 (1.7) mL·min^-1·100 g^-1 8 h after resection (P = 0.004). Despite this increase in relative oxygen uptake, total hepatic oxygen consumption (V̇o₂) was not maintained, and markers of hypoxia and anaerobic metabolism were significantly increased in hepatocytes after resection. Reduced postoperative portal flow was associated with significantly decreased levels of aspartate aminotransferase and bilirubin and increased hepatic clearance of indocyanine green. In conclusion, major liver resection was associated with persistent portal hyperperfusion, loss of the hepatic arterial buffer response, decreased total hepatic V̇o₂ and with increased anaerobic metabolism. Portal flow modulation by partial portal vein occlusion attenuated liver injury after extended liver resection.NEW & NOTEWORTHY Because of continuous monitoring, the experiments allow precise observation of the influence of liver resection on systemic and local abdominal hemodynamic alterations and oxygen metabolism. Major liver resection is associated with significant and persistent portal hyperperfusion and loss of hepatic arterial buffer response. The correlation of portal hyperperfusion and parameters of liver injury and dysfunction offers a novel therapeutic option to attenuate liver injury after extended liver resection.

[Vascular management in anatomical liver resection]

The vascular management in anatomical liver resection plays a pivotal role in maintaining an adequately functional residual liver volume. In this respect it is essential to guarantee an adequate portal and arterial inflow as well venous outflow for the whole residual liver (lobe or segments). To achieve this, the liver surgeon should have excellent perioperative imaging, surgical expertise based on knowledge of vascular anatomy, physiology and hemodynamics of the liver and a well-designed and cautious operative strategy. The use of intraoperative ultrasonography (with or without contrast enhancement) and modern parenchymal dissectors (e.g. ultrasound or water jet dissectors) are strongly recommended.

A critical appraisal of the hemodynamic signal driving liver regeneration

BACKGROUND

Many aspects of the signaling mechanisms involved in the initiation of hepatic regeneration are under current investigation. Nevertheless, the actual mechanisms switching liver regeneration on and off are still unknown. Hemodynamic changes in the liver following partial hepatectomy have been suggested to be a primary stimulus in triggering liver regeneration. Most of the new knowledge about the impact of hemodynamic changes on liver regeneration is both conceptually important and directly relevant to clinical problems.

PURPOSE

The purpose of this review is therefore to exclusively address the hemodynamic signal driving the liver regeneration process.