Is embolization of segment 4 portal veins before extended right hepatectomy justified?

Background: Preoperative portal vein embolization (PVE) is increasingly used as a preparation for major hepatectomy in patients with inadequate liver remnant volume or function. However, whether segment 4 (S4) portal veins should be embolized is controversial. The effect of S4 PVE on the volume gain of segments 2 and 3 (S2+3) was examined. Methods: Among 73 patients with uninjured liver who underwent right portal vein embolization (RPVE, n = 15) or RPVE extended to S4 portal veins (RPVE+4, n = 58), volume changes in S2+3 and S4 after embolization were compared. Clinical outcomes and PVE complications were assessed. Results: After a median of 27 days, the S2+3 volume increased significantly after both RPVE and RPVE+4, but the absolute increase was significantly higher for RPVE+4 (median, 106 mL vs 141 mL; P = .044), as was the hypertrophy rate (median, 26% vs 54%; P = .021). There was no significant difference between RPVE and RPVE+4 in the absolute S4 volume increase (52 mL for RPVE vs 55 mL for RPVE+4; P = .61) or the hypertrophy rate of S4 (30% for RPVE vs 26% for RPVE+4; P = .45). Complications of PVE occurred in 1 patient (7%) after RPVE and 6 (10%) after RPVE+4 (P > .99). No PVE complication precluded subsequent resection. Curative hepatectomy was performed in 13 patients (87%) after RPVE and 40 (69%) after RPVE+4 (P = .21). Conclusions: RPVE+4 significantly improves S2+3 hypertrophy compared with RPVE alone. Extending RPVE to S4 does not increase PVE-associated complications.