Extension of right portal vein embolization to segment IV portal branches

Hypothesis: Routine embolization of segment IV, combined with right portal vein embolization (PVE), has been suggested in patients who are candidates for right trisegmentectomy to induce higher and faster hypertrophy of segments II-III. Our objective was to compare hypertrophy of segments II-III induced by PVE with and without extension to segment IV in patients undergoing major hepatectomy. Methods: Twenty-six consecutive patients were prospectively evaluated; the future remnant liver volume was calculated using the portal phase of spiral computed tomographic scans before and 3 to 4 weeks after right PVE (group R, n=13), which was extended to segment IV branches in 13 patients (group L). Results: Twenty patients (76.9%) underwent the scheduled hepatic resection. Of the 6 patients who did not undergo the planned operation, 5 showed disease progression; in 1 patient (group L), there was an insufficient increase of the future remnant liver volume due to the presence of embolizing material in the left lobe. The mean±SD time between PVE and volume measurements was 31.8±9.3 days. The overall mean±SD future remnant liver volume increase was 53.1%±24.8%; the increase for segment IV was significantly higher in group R than group L. The mean±SD post-PVE volumes of segments II-III and the rate of volume increase were similar in the 2 groups: group R, 348.4±83.1 cm³ and 67.8%±30.8%, respectively, vs group L, 391.2±78.05 cm³ and 56.1%±35.1%, respectively (P=.20 and P=.40). Conclusion: Extension of embolization to segment IV portal branches should not be routinely used because a similar volume increase of segments II-III can be simply achieved by right PVE.