Liver Venous Deprivation (LVD) Versus Portal Vein Embolization (PVE) Alone Prior to Extended Hepatectomy: A Matched Pair Analysis

Future liver remnant hypertrophy and postoperative outcomes: a retrospective comparison between segmental and main right portal vein embolization

OBJECTIVE

To assess the efficacy of segmental right portal vein embolization (SRPVE) versus main right portal vein embolization (MRPVE) in preoperative preparation for major hepatectomy.

METHODS

This retrospective single-center study included 220 consecutive patients who underwent portal vein embolization (PVE) before (extended) right hemihepatectomy between January 2014 and June 2021. Seventy-one patients underwent selective segmental embolization (SRPVE) and 149 patients underwent MRPVE. Volumetric analysis was conducted before PVE and before surgery. Key endpoints included evaluation of future liver remnant (FLR) hypertrophy, intraoperative complexity, and postoperative complications, technical success, clinical success, complications (Clavien-Dindo and CIRSE classifications), as well as evaluation of different factors which may influence hypertrophy of the FLR.

RESULTS

Technical success rate was 100% in the SRPVE group and 99.3% in the MRPVE group (p = 0.15). Clinical success rate was comparable between both techniques, measuring 95.8% in the SRPVE group and 95.3% in the MRPVE group (p = 0.18). Absolute hypertrophy (FLRabh) of the FLR was comparable between both techniques, measuring 47.15% in the SRPVE group and 40.78% in the MRPVE group (p = 0.54). Complication rates did not differ significantly (p = 0.12). Partial thrombosis involving the left portal vein, main portal vein, or mesentericosplenic region was observed in 2.8% of the patients in the SRPVE group vs 3.4% in the MRPVE group (p = 0.95). CIRSE Class II-VI complications were slightly higher in the MRPVE group (10.7% vs 9.8%, p = 0.82). Postoperative complications with Clavien-Dindo class ≥ IIIa occurred in 10.1% % in the MRPVE group vs 9.9% the SRPVE group (p = 0.92). Liver cirrhosis had a significant negative correlation with sFLR % increase following PVE (r = -0.54; p = 0.027). Neoadjuvant chemotherapy was also associated with reduced FLR hypertrophy following PVE, with a median sFLR% change of 63.8% (IQR: 60.8% - 75.2%) in patients who received neoadjuvant chemotherapy (n = 66 patients, 30%) compared to 82.6% (IQR: 77.4% - 84.2%) in those without chemotherapy (n = 154 patients, 70%).

CONCLUSION

Selective segmental right portal vein embolization, sparing the main right portal vein, offers a safe and effective alternative to MRPVE, achieving comparable FLR hypertrophy while potentially simplifying intraoperative procedures and reducing postprocedural complications. Future research should focus on conducting large, prospective, multicenter trials to further compare the long-term outcomes of this technique, particularly with regard to liver regeneration, postoperative liver function, complications and overall survival.

Propensity Score-Matched Analysis of Liver Venous Deprivation and Portal Vein Embolization Before Planned Hepatectomy in Patients with Extensive Colorectal Liver Metastases and High-Risk Factors for Inadequate Regeneration

BACKGROUND

Liver venous deprivation (LVD) is known to induce better future liver remnant (FLR) hypertrophy than portal vein embolization (PVE). The role of LVD, compared with PVE, in inducing FLR hypertrophy and allowing safe hepatectomy for patients with extensive colorectal liver metastases (CLM) and high-risk factors for inadequate hypertrophy remains unclear.

METHODS

Patients undergoing LVD (n = 22) were matched to patients undergoing PVE (n = 279) in a 1:3 ratio based on propensity scores, prior to planned hepatectomy for CLM at a single center (1998-2023). The propensity scores accounted for high-risk factors for inadequate hypertrophy, namely pre-procedure standardized FLR (sFLR), body mass index, number of systemic therapy cycles, an extension of PVE to segment IV portal vein branches, prior resection, and chemotherapy-associated liver injury.

RESULTS

The matched cohort included 78 patients (LVD, n = 22; PVE, n = 56). Baseline characteristics were comparable. The number of tumors in the whole liver was similar but more LVD patients had five or more tumors in the left liver (32% vs. 11%; p = 0.024). Post-procedure sFLR was similar but LVD patients had a significantly higher degree of hypertrophy (16% vs. 11%; p = 0.017) and kinetic growth rate (3.9 vs. 2.4% per week; p = 0.006). More LVD patients underwent extended right hepatectomy (93% vs. 55%; p = 0.008). Only one patient had postoperative hepatic insufficiency after PVE, and no patients died within 90 days of hepatectomy.

CONCLUSION

In patients with extensive CLM and high-risk factors, LVD is associated with better FLR hypertrophy compared with PVE and allows for safely performing curative-intent extended major hepatectomy.

Optimal treatment strategies for borderline resectable liver metastases from colorectal cancer

BACKGROUND

Traditionally, colorectal liver metastases (CRLMs) are divided into "initially resectable" and "initially unresectable." The terminology "borderline resectable" continues to be elusive without any common consensus or definition. This narrative review aims to decode the conundrum of "borderline resectable CRLM (BR-CRLM)" and to discuss optimal treatment strategies.

METHODS

A comprehensive review was performed using Medline/PubMed and Web of Science databases with a search period ending on January 1, 2024. Using PubMed, the terms "CRLM," "BR-CRLM," and "management of BR-CRLM" were searched.

RESULTS

The 2016 European Society for Medical Oncology guidelines defined the term "resectability" in CRLM using the "technical (surgical) criteria" and the "oncologically criteria." These 2 criteria form the basis of defining BR-CRLM. Thus, BR-CRLM can be either technically easy but with unfavorable oncologically criteria or technically difficult with favorable oncologically criteria. Although defining BR-CRLM by incorporating both these criteria seems to be the most logical way forward, there is currently a lot of heterogeneity in the literature. It is generally agreed upon that some form of chemotherapy needs to be administered in BR-CRLM before embarking on surgery. Conversion chemotherapy is used in patients with BR-CRLM in which there is a possibility of resection after effective downsizing. Along with improved effective chemotherapy, great strides have been made in pushing the limits of surgery to achieve resectability in this subset of patients.

CONCLUSION

Advanced surgical techniques and locoregional liver-directed therapies coupled with perioperative chemotherapy with or without targeted therapy have made long-term survival benefit, a reality in patients with BR-CRLM. Thus, the time has come to recognize "BR-CRLM" as a distinct entity.

Liver Vein Deprivation versus Portal Vein Embolization: Retrospective Review of Safety and Effectiveness

PURPOSE

To compare the safety and effectiveness of liver vein deprivation (LVD) and portal vein embolization (PVE) in patients scheduled to undergo liver resection.

MATERIALS AND METHODS

This retrospective cohort study included 59 patients who underwent either PVE (n = 28) or LVD (n = 31) in preparation for liver resection. The primary outcome was percent change in future liver remnant volume (FLRV). The secondary endpoints were degree of hypertrophy (DH) and kinetic growth rate (KGR).

RESULTS

Low baseline FLRV and time interval in days between the procedure and follow-up imaging (Ti) positively impacted the primary and secondary endpoints in both groups. Percent change in FLRV was higher in the LVD group (52.8% ± 5.3) than in the PVE group (22.3% ± 3.0, P < .001). DH was also higher in the LVD group (15.4% ± 1.7) than in the PVE group (6.4% ± 0.9, P < .001). KGR did not differ significantly between groups (LVD, 0.54%/d ± 0.06; PVE, 0.35%/d ± 0.1; P = .239). When patients with a baseline standardized FLRV of >35% were excluded from the analysis, the LVD group demonstrated higher values than the PVE group in KGR (0.57%/d ± 0.06 vs 0.29%/d ± 0.05, P < .001), percent change in FLRV (64.2% ± 6.0 vs 25.9% ± 4.3, P < .001), and DH (15.4% ± 1.4 vs 6.6% ± 1.0, P < .001). No adverse events were noted in either group.

CONCLUSIONS

LVD appears to be safe and may be superior to PVE in inducing hypertrophy of future liver remnant in patients scheduled to undergo surgical resection.

Comparison of liver venous deprivation with portal vein embolization alone in patients undergoing major liver resection: a systematic review and meta-analysis

BACKGROUND

The clinical efficacy and safety between liver venous deprivation (LVD) and portal vein embolization (PVE) prior to major hepatectomy is still unclear.

METHODS

Studies comparing LVD and PVE were obtained by systemically searching PubMed, Embase, and Cochrane Library Central databases through 22 December 2023.

RESULTS

Ten studies including 588 patients were reviewed. Compared with PVE group, LVD group exhibited an increased liver resection rate (OR, 1.89; 95% CI, 1.13-3.15; P = 0.01), a faster KGR (MD, 1.37; 95% CI, 0.31-2.42; P = 0.01), and a shorter time to hepatectomy (MD, -6.66; 95% CI, -8.03 to -5.30; P < 0.0001). The pooled results showed that post-embolization complications (OR, 1.35; 95% CI, 0.66-2.74), overall postoperative complications (OR, 1.09; 95% CI, 0.68-1.75), severe complications (Clavien-Dindo ≥ III) (OR, 0.70; 95% CI, 0.43-1.14), and 90-day mortality (OR, 0.38; 95% CI, 0.13-1.09) were not significantly different in both groups. LVD group had significantly lower post-hepatectomy liver failure (PHLF) than PVE group (OR, 0.45; 95% CI, 0.22-0.91; P = 0.03).

CONCLUSION

LVD outperforms PVE regarding liver resection rate and future liver remnant (FLR) hypertrophy and shows comparable safety to PVE. In addition, LVD allowed for major hepatectomy with lower incidence of PHLF.

CIRSE Standards of Practice on Portal Vein Embolization and Double Vein Embolization/Liver Venous Deprivation

This CIRSE Standards of Practice document is aimed at interventional radiologists and provides best practices for performing liver regeneration therapies prior to major hepatectomies, including portal vein embolization, double vein embolization and liver venous deprivation. It has been developed by an expert writing group under the guidance of the CIRSE Standards of Practice Committee. It encompasses all clinical and technical details required to perform liver regeneration therapies, revising the indications, contra-indications, outcome measures assessed, technique and expected outcomes.

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.

Efficacy and perioperative safety of different future liver remnant modulation techniques: a systematic review and network meta-analysis

BACKGROUND

In daily clinical practice, different future liver remnant (FLR) modulation techniques are increasingly used to allow a liver resection in patients with insufficient FLR volume. This systematic review and network meta-analysis aims to compare the efficacy and perioperative safety of portal vein ligation (PVL), portal vein embolization (PVE), liver venous deprivation (LVD) and associating liver partition and portal vein ligation for staged hepatectomy (ALPPS).

METHODS

A literature search for studies comparing liver resections following different FLR modulation techniques was performed in MEDLINE, Embase and Cochrane Central, and pairwise and network meta-analyses were conducted.

RESULTS

Overall, 23 studies comprising 1557 patients were included. LVD achieved the greatest increase in FLR (17.32 %, 95% CI 2.49-32.15), while ALPPS was most effective in preventing dropout before the completion hepatectomy (OR 0.29, 95% CI 0.15-0.55). PVL tended to be associated with a longer time to completion hepatectomy (MD 5.78 days, 95% CI -0.67-12.23). Liver failure occurred less frequently after LVD, compared to PVE (OR 0.35, 95% CI 0.14-0.87) and ALPPS (OR 0.28, 95% CI 0.09-0.85).

DISCUSSION

ALPPS and LVD seem superior to PVE and PVL in terms of achieved FLR increase and subsequent treatment completion. LVD was associated with lower rates of post hepatectomy liver failure, compared to both PVE and ALPPS. A summary of the protocol has been prospectively registered in the PROSPERO database (CRD42022321474).

Extended Right Hepatectomy following Clearance of the Left Liver Lobe and Portal Vein Embolization for Curatively Intended Treatment of Extensive Bilobar Colorectal Liver Metastases: A Single-Center Case Series

BACKGROUND

Two-staged hepatectomy (TSH) including portal vein embolization (PVE) may offer surgical treatment for extensive bilobar colorectal liver metastases (CRLM). This study aimed to investigate the feasibility and outcomes of extended right hepatectomy (ERH) within TSH including PVE for patients with extended CRLM.

METHODS

We retrospectively collected data of patients who underwent TSH for extended CRLM between 2015 and 2021 at our institution. Clearance of the left liver lobe (clear-up, CU) associated with PVE was followed by ERH.

RESULTS

Minimally invasive (n = 12, 46%, MIH) or open hepatectomy (n = 14, 54%, OH) was performed. Postoperative major morbidity and 90-day mortality were 54% and 0%. Three-year overall survival was 95%. Baseline characteristics, postoperative and long-term outcomes were comparable between MIH and OH. However, hospital stay was significantly shorter after MIH (8 vs. 15 days, p = 0.008). Additionally, the need for intraoperative transfusions tended to be lower in the MIH group (17% vs. 50%, p = 0.110).

CONCLUSIONS

ERH following CU and PVE for extended CRLM is feasible and safe in laparoscopic and open approaches. MIH for ERH may result in shorter postoperative hospital stays. Further high-volume, multicenter studies are required to evaluate the potential superiority of MIH.

A systematic review and meta-analysis of liver venous deprivation versus portal vein embolization before hepatectomy: future liver volume, postoperative outcomes, and oncological safety

Introduction

This systematic review aimed to compare liver venous deprivation (LVD) with portal vein embolization (PVE) in terms of future liver volume, postoperative outcomes, and oncological safety before major hepatectomy.

Methods

We conducted this systematic review and meta-analysis following the PRISMA guidelines 2020 and AMSTAR 2 guidelines. Comparative articles published before November 2022 were retained.

Results

The literature search identified nine eligible comparative studies. They included 557 patients, 207 in the LVD group and 350 in the PVE group. This systematic review and meta-analysis concluded that LVD was associated with higher future liver remnant (FLR) volume after embolization, percentage of FLR hypertrophy, lower failure of resection due to low FLR, faster kinetic growth, higher day 5 prothrombin time, and higher 3 years' disease-free survival. This study did not find any difference between the LVD and PVE groups in terms of complications related to embolization, FLR percentage of hypertrophy after embolization, failure of resection, 3-month mortality, overall morbidity, major complications, operative time, blood loss, bile leak, ascites, post hepatectomy liver failure, day 5 bilirubin level, hospital stay, and three years' overall survival.

Conclusion

LVD is as feasible and safe as PVE with encouraging results making some selected patients more suitable for surgery, even with a small FLR.

Systematic review registration

The review protocol was registered in PROSPERO before conducting the study (CRD42021287628).

[The Russian consensus on the treatment of intrahepatic cholangiocarcinoma]

The Russian consensus on the treatment of intrahepatic cholangiocarcinoma was prepared by the group of experts consisting of surgeons, interventional radiologists, radiation therapists and oncologists. The purposes of this consensus are clarification and consolidation of opinions of multidisciplinary team on the following issues of management of patients with intrahepatic cholangiocarcinoma: indications for surgical treatment, features of therapeutic tactics for mechanical jaundice, technical aspects of liver resection, prevention of post-resection liver failure, indications for liver resection using transplantation technologies, laparoscopic and robot-assisted liver resection, perioperative systemic chemotherapy, local non-resection/non-radiotherapy methods of treatment, radiotherapy, follow-up and choice of treatment for recurrence.

Multi-organ Radiomics-Based Prediction of Future Remnant Liver Hypertrophy Following Portal Vein Embolization

BACKGROUND

Portal vein embolization (PVE) is used to induce remnant liver hypertrophy prior to major hepatectomy. The purpose of this study was to evaluate the predictive value of baseline computed tomography (CT) data for future remnant liver (FRL) hypertrophy after PVE.

METHODS

In this retrospective study, all consecutive patients undergoing right-sided PVE with or without hepatic vein embolization between 2018 and 2021 were included. CT volumetry was performed before and after PVE to assess standardized FRL volume (sFRLV). Radiomic features were extracted from baseline CT after segmenting liver (without tumor), spleen and bone marrow. For selecting features that allow classification of response (hypertrophy ≥ 1.33), a stepwise dimension reduction was performed. Logistic regression models were fitted and selected features were tested for their predictive value. Decision curve analysis was performed on the test dataset.

RESULTS

A total of 53 patients with liver tumor were included in this study. sFRLV increased significantly after PVE, with a mean hypertrophy of FRL of 1.5 ± 0.3-fold. sFRLV hypertrophy ≥ 1.33 was reached in 35 (66%) patients. Three independent radiomic features, i.e. liver-, spleen- and bone marrow-associated, differentiated well between responders and non-responders. A logistic regression model revealed the highest accuracy (area under the curve 0.875) for the prediction of response, with sensitivity of 1.0 and specificity of 0.5. Decision curve analysis revealed a positive net benefit when applying the model.

CONCLUSIONS

This proof-of-concept study provides first evidence of a potential predictive value of baseline multi-organ radiomics CT data for FRL hypertrophy after PVE.

Liver Venous Deprivation for Rapid Liver Hypertrophy Before Major Hepatectomy: A Case Report

Liver venous deprivation (LVD) is an emerging, minimally invasive strategy to induce rapid liver hypertrophy of the future liver remnant (FLR) before a major hepatectomy. LVD (aka "double vein embolization") entails same-session percutaneous embolization of the portal and hepatic veins of the planned liver resection. This report discusses LVD's utilization and technical challenges in managing a 49-year-old male with recurrent multifocal colorectal liver metastases (CRLM). The patient initially underwent neoadjuvant FOLFOX chemotherapy followed by a simultaneous laparoscopic sigmoid colectomy and liver surgery (microwave ablation of segment V and wedge resections of segment one and IVb), followed by completion of chemotherapy. The patient had an R0 resection with clear colon and liver surgical margins. Nine months after the initial surgery, the patient had a rise in tumor markers, and surveillance imaging demonstrated recurrence of liver metastases in segments I and V. LVD was performed by interventional radiology, which led to a 28% increase in FLR (segments II, III, and IV); initially measuring 464 cm3 before LVD and measuring 594 cm3 on post-procedure day 21. The patient underwent right hemi-hepatectomy and caudate resection on post-procedure day 29. The patient did not have any complications and was discharged on postoperative day 6. The patient remains disease-free with no evidence of recurrence at 12 months follow-up.

Proceedings of the 27th Annual Congress of the International Liver Transplantation Society

After a virtual congress in 2021 and a previous absence in 2020 because of the coronavirus disease 2019 pandemic, the 27th Annual Congress of the International Liver Transplantation Society was held from May 4 to 7, 2022, in a hybrid format in Istanbul, with 1123 (58% on-site) liver transplant professionals from 61 countries attending the meeting. The hybrid format successfully achieved a balance of much yearned-for "in-person interaction" and global online participation. Almost 500 scientific abstracts were presented. In this report, the Vanguard Committee aims to present a summary of key invited lectures and selected abstracts for the liver transplant community.

Locoregional Therapy in the Management of Intrahepatic Cholangiocarcinoma: Is There Sufficient Evidence to Guide Current Clinical Practice?

PURPOSE OF REVIEW

Intrahepatic cholangiocarcinoma (iCCA) carries a dismal prognosis and, despite increasing incidence, still lacks effective treatments. In this scenario, locoregional therapies (LRT) are gaining interest as they may be effective at local tumor control and complementary to surgical and non-surgical approaches. In this article, we will review the evolving role of LRT performed by interventional radiologists in the management of iCCA.

RECENT FINDINGS

Accumulating retrospective evidence indicates that ablative therapies and transarterial embolizations are of benefit for iCCA with unresectable disease, demonstrating promising safety profiles and prolonged or comparable survival outcomes compared to systemic therapy and surgery. Additionally, for surgical candidates, portal ± hepatic venous embolization can improve the safety of hepatectomy by inducing preoperative hypertrophy of the non-involved liver lobe. LRTs are playing an increasingly important role in the multimodal treatment of iCCA from various perspectives with reduced toxicity relative to traditional treatments. To expand the scope of applications for LRTs in this setting, future prospective randomized studies are needed to confirm their efficacy and advantage.

Portal vein embolization versus dual vein embolization for management of the future liver remnant in patients undergoing major hepatectomy: meta-analysis

BACKGROUND

This meta-analysis aimed to compare progression to surgery, extent of liver hypertrophy, and postoperative outcomes in patients planned for major hepatectomy following either portal vein embolization (PVE) or dual vein embolization (DVE) for management of an inadequate future liver remnant (FLR).

METHODS

An electronic search was performed of MEDLINE, Embase, and PubMed databases using both medical subject headings (MeSH) and truncated word searches. Articles comparing PVE with DVE up to January 2022 were included. Articles comparing sequential DVE were excluded. ORs, risk ratios, and mean difference (MD) were calculated using fixed and random-effects models for meta-analysis.

RESULTS

Eight retrospective studies including 523 patients were included in the study. Baseline characteristics between the groups, specifically, age, sex, BMI, indication for resection, and baseline FLR (ml and per cent) were comparable. The percentage increase in hypertrophy was larger in the DVE group, 66 per cent in the DVE group versus 27 per cent in the PVE group, MD 39.07 (9.09, 69.05) (P = 0.010). Significantly fewer patients failed to progress to surgery in the DVE group than the PVE group, 13 per cent versus 25 per cent respectively OR 0.53 (0.31, 0.90) (P = 0.020). Rates of post-hepatectomy liver failure 13 per cent versus 22 per cent (P = 0.130) and major complications 20 per cent versus 28 per cent (Clavien-Dindo more than IIIa) (P = 0.280) were lower. Perioperative mortality was lower with DVE, 1 per cent versus 10 per cent (P = 0.010).

CONCLUSION

DVE seems to produce a greater degree of hypertrophy of the FLR than PVE alone which translates into more patients progressing to surgery. Higher quality studies are needed to confirm these results.

Resectability of bilobar liver tumours after simultaneous portal and hepatic vein embolization versus portal vein embolization alone: meta-analysis

BACKGROUND

Many patients with bi-lobar liver tumours are not eligible for liver resection due to an insufficient future liver remnant (FLR). To reduce the risk of posthepatectomy liver failure and the primary cause of death, regenerative procedures intent to increase the FLR before surgery. The aim of this systematic review is to provide an overview of the available literature and outcomes on the effectiveness of simultaneous portal and hepatic vein embolization (PVE/HVE) versus portal vein embolization (PVE) alone.

METHODS

A systematic literature search was conducted in PubMed, Web of Science, and Embase up to September 2022. The primary outcome was resectability and the secondary outcome was the FLR volume increase.

RESULTS

Eight studies comparing PVE/HVE with PVE and six retrospective PVE/HVE case series were included. Pooled resectability within the comparative studies was 75 per cent in the PVE group (n = 252) versus 87 per cent in the PVE/HVE group (n = 166, OR 1.92 (95% c.i., 1.13-3.25)) favouring PVE/HVE (P = 0.015). After PVE, FLR hypertrophy between 12 per cent and 48 per cent (after a median of 21-30 days) was observed, whereas growth between 36 per cent and 67 per cent was reported after PVE/HVE (after a median of 17-31 days). In the comparative studies, 90-day primary cause of death was similar between groups (2.5 per cent after PVE versus 2.2 per cent after PVE/HVE), but a higher 90-day primary cause of death was reported in single-arm PVE/HVE cohort studies (6.9 per cent, 12 of 175 patients).

CONCLUSION

Based on moderate/weak evidence, PVE/HVE seems to increase resectability of bi-lobar liver tumours with a comparable safety profile. Additionally, PVE/HVE resulted in faster and more pronounced hypertrophy compared with PVE alone.