Early observations and pilot data that first suggested a new direction
Makuuchi and colleagues first described portal vein embolization (PVE) in 1990 as a technique to induce contralateral liver hypertrophy before major hepatectomy. In their initial series of 14 patients with hilar bile duct carcinoma, preoperative embolization of the ipsilateral portal vein induced measurable atrophy of the embolized lobe and hypertrophy of the future liver remnant (FLR) without major complications. This concept leveraged the liver's innate regenerative capacity and transformed the approach to patients with marginal FLR volumes.
Landmark RCTs and pivotal trials that established the evidence base
Over the following two decades, PVE became the established standard for augmenting FLR volume before extended hepatectomy. Typical FLR hypertrophy of 10-30% occurred over 4-6 weeks after embolization. Large institutional series demonstrated that PVE reduced post-hepatectomy liver failure and mortality in patients with marginal remnant volumes. The technique was validated across multiple indications including colorectal liver metastases, hepatocellular carcinoma, and cholangiocarcinoma.
Follow-up studies, subgroup analyses, and real-world validation
ALPPS, first reported by Schnitzbauer in 2012, achieved dramatically faster FLR hypertrophy (74% in 9 days vs 10-30% over 4-6 weeks with PVE) by combining portal vein ligation with in-situ liver parenchymal transection. The international ALPPS registry (>1,200 cases by 2019) demonstrated 100% stage-2 resectability but at the cost of higher morbidity and mortality (7-12% for CRLM). Subsequent refinements, including partial ALPPS and mini-ALPPS techniques, reduced complications while maintaining the rapid hypertrophy advantage. Liver venous deprivation emerged as another augmentation strategy combining portal and hepatic vein embolization.
Integration into clinical practice guidelines and recommendations
PVE is recommended as the standard volumetric augmentation technique before major hepatectomy when FLR is insufficient. ALPPS is reserved for cases where PVE fails or hypertrophy is insufficient, performed only at experienced hepatobiliary centers.
IHPBA
PVE recommended as first-line FLR augmentation; ALPPS for selected cases at experienced centers when PVE insufficient
Now
Current standard of care and ongoing research directions
PVE remains the standard first-line approach for FLR augmentation before major hepatectomy. ALPPS has matured through refined patient selection and technique modifications, with mortality reduced but still higher than PVE. Liver venous deprivation (combined portal and hepatic vein embolization) is emerging as a potentially safer alternative to ALPPS that achieves comparable hypertrophy rates. Head-to-head comparisons between these augmentation strategies are ongoing.
Portal vein embolization (PVE), pioneered by Makuuchi in 1990, involves percutaneous embolization of the portal vein branch supplying the liver to be resected, inducing 10-30% contralateral hypertrophy over 4-6 weeks. ALPPS, described by Schnitzbauer in 2012, combines portal vein ligation with in-situ liver parenchymal transection, achieving 74% hypertrophy in just 9 days but with higher morbidity (7-12% mortality for CRLM vs 2-4% for PVE). PVE is the first-line approach; ALPPS is reserved for cases where PVE fails or timing is critical.
When is FLR augmentation necessary?+
FLR augmentation is typically recommended when the future liver remnant is less than 20% in patients with normal liver parenchyma, less than 30% after chemotherapy, or less than 40% in cirrhotic patients. Without augmentation, patients with insufficient FLR face a high risk of post-hepatectomy liver failure, which carries mortality rates of 50-90%.
