Changes in clinicopathological findings after portal vein embolization

Portal vein embolization is becoming more common as a method of preventing hepatic failure after an extended hepatectomy but its mechanism is not well understood. This clinicopathological study focused on its mechanism.

Thirty patients who underwent extended hepatectomy after portal vein embolization were evaluated. Liver volume was measured before and after portal vein embolization, and histological studies were performed to examine morphological changes, morphometric parameters and apoptosis of hepatocytes.

The mean volume of the non-embolized lobe grew significantly from 392 to 462 mL after portal vein embolization (P < 0.0001). The hypertrophy ratio of the non-embolized lobe (100 x volume change during portal vein embolization/volume before portal vein embolization, %) was correlated closely with the volume of the non-embolized lobe before portal vein embolization (r = -0.65, P < 0.0001). Histological study showed the embolized lobe hepatocytes to be atrophic, partly necrotic and apoptotic. In the non-embolized lobe, the mean hepatocyte volume was 8686 micron 3 (control: 6544 micron 3) and the mean hepatocyte count was 109 x 10(6)/mL (control: 122 x 10(6)/mL).

The enlargement of the non-embolized lobe was caused by hypertrophy rather than hyperplasia suggesting hyperfunction. The resection of the atrophic embolized lobe, leaving the hypertrophic non-embolized lobe was thought to be less surgically stressful than hepatectomy without portal vein embolization.