Liver volumetry and liver-regenerative interventions: history, rationale, and emerging tools

BACKGROUND

Postoperative hepatic insufficiency (PHI) is the most feared complication after hepatectomy. Volume of the future liver remnant (FLR) is one objectively measurable indicator to identify patients at risk of PHI. In this review, we summarized the development and rationale for the use of liver volumetry and liver-regenerative interventions and highlighted emerging tools that could yield new advancements in liver volumetry.

METHODS

A review of MEDLINE/PubMed, Embase, and Cochrane Library databases was conducted to identify literature related to liver volumetry. The references of relevant articles were reviewed to identify additional publications.

RESULTS

Liver volumetry based on radiologic imaging was developed in the 1980s to identify patients at risk of PHI and later used in the 1990s to evaluate grafts for living donor living transplantation. The field evolved in the 2000s by the introduction of standardized FLR based on the hepatic metabolic demands and in the 2010s by the introduction of the degree of hypertrophy and kinetic growth rate as measures of the FLR regenerative and functional capacity. Several liver-regenerative interventions, most notably portal vein embolization, are used to increase resectability and reduce the risk of PHI. In parallel with the increase in automation and machine assistance to physicians, many semi- and fully automated tools are being developed to facilitate liver volumetry.

CONCLUSION

Liver volumetry is the most reliable tool to detect patients at risk of PHI. Advances in imaging analysis technologies, newly developed functional measures, and liver-regenerative interventions have been improving our ability to perform safe hepatectomy.

Portal Vein Embolization Reduces Postoperative Hepatic Insufficiency Associated with Postchemotherapy Hepatic Atrophy

BACKGROUND

The risk of postoperative hepatic insufficiency (PHI) is increased among patients with significant postchemotherapy hepatic atrophy. The primary aim of this study was to evaluate whether the liver regeneration stimulated by portal vein embolization (PVE) can protect against PHI.

METHODS

Clinicopathological features of 177 patients treated with preoperative chemotherapy followed by PVE and hepatectomy were reviewed. Degree of atrophy was defined as the ratio of percentage difference in total liver volume (estimated by manual volumetry) to standardized liver volume. Kinetic growth rate (KGR, degree of hypertrophy [absolute % change in future liver remnant volume] divided by the number of weeks after PVE) and PHI events were compared between patients with degree of atrophy <10 vs ≥10%. Risk factors for the PHI were assessed using logistic regression.

RESULTS

Seventy patients (40%) experienced significant hepatic atrophy ≥10% following preoperative chemotherapy. PHI rates were not significantly increased in patients who experienced significant hepatic atrophy (5.6 vs 8.6%, P = 0.443). KGR <2%/week (odds ratio, 8.10, P = 0.037) was the sole independent preoperative predictor of PHI. KGR ≥2% was associated with decreased PHI in both patients with <10% atrophy (0 vs 9.5%, P = 0.035) and ≥10% atrophy (2.6 vs 16.0%, P = 0.044).

CONCLUSIONS

Even in high-risk patients with ≥10% degree of atrophy from preoperative chemotherapy, KGR ≥2% mitigates the deleterious effects of hepatic atrophy and significantly reduces PHI to almost zero. In these high-risk patients, PVE with KGR calculation remains the most important preoperative technique to reduce liver failure after major hepatectomy.

Hepatic atrophy following preoperative chemotherapy predicts hepatic insufficiency after resection of colorectal liver metastases

BACKGROUND & AIMS

For patients with colorectal liver metastases (CLM) undergoing major hepatectomy, extensive preoperative chemotherapy has been associated with increased morbidity and mortality. The impact of extensive chemotherapy on total liver volume (TLV) change is unclear. The aims of the current study were twofold: (1) to determine the change of TLV following preoperative chemotherapy in patients undergoing resection for CLM and (2) to investigate the correlations among TLV change, postoperative hepatic insufficiency (PHI), and death from liver failure.

METHODS

Clinicopathological features of patients with CLM who underwent preoperative chemotherapy and curative resection were reviewed (2008-2015). TLV change (degree of atrophy) was defined as the percentage difference of TLV (estimated by manual volumetry)/standardized liver volume (SLV) ratio: ([Pre-chemotherapy TLV]-[Post-chemotherapy TLV])×100÷SLV (%). Receiver operating characteristic (ROC) analysis was performed to decide the accurate cut-off value of degree of atrophy to predict PHI. The Cox proportional hazard model was performed to identify the predictors of severe degree of atrophy and PHI.

RESULTS

The study cohort consisted of 459 patients, of which 154 patients (34%) underwent extensive preoperative chemotherapy (≥7 cycles). ROC analysis identified the degree of atrophy ≥10% as an accurate cut-off to predict PHI, which was significantly correlated with ≥7 cycles of preoperative chemotherapy. Four factors independently predicted PHI: standardized future liver remnant ≤30% (odds ratio [OR] 4.03, p=0.019), high aspartate aminotransferase-to-platelet ratio index (OR 5.27, p=0.028), degree of atrophy ≥10% (OR 43.5, p<0.001), and major hepatic resection (OR 5.78, p=0.005). Degree of atrophy ≥10% was associated with increased mortality from liver failure (0% [0/374] vs. 15% [13/85], p<0.001).

CONCLUSION

Extensive preoperative chemotherapy induced significant atrophic change of TLV. Degree of atrophy ≥10% is an independent predictor of PHI and death in patients with CLM undergoing preoperative chemotherapy and resection.

LAY SUMMARY

Extensive preoperative chemotherapy for patients with colorectal liver metastases (CLM) could induce hepatic atrophy. A higher degree of atrophy is an independent predictor of postoperative hepatic insufficiency and death in patients with CLM undergoing preoperative chemotherapy and resection.