Outcome of patients with perihilar cholangiocarcinoma and previous biliary instrumentation: an observational study.

BACKGROUND: To assess the outcome of previously untreated patients with perihilar cholangiocarcinoma who present to a cancer referral center with or without pre-existing trans-papillary biliary drainage. METHODS: Consecutive patients with a diagnosis of perihilar cholangiocarcinoma presenting between January 1, 2013, and December 31, 2017, were identified from a prospective surgical database and by a query of the institutional database. Of 237 patients identified, 106 met inclusion criteria and were reviewed. Clinical information was obtained from the Electronic Medical Record and imaging studies were reviewed in the Picture Archiving and Communication System. RESULTS: 73 of 106 patients (69%) presenting with a new diagnosis of perihilar cholangiocarcinoma underwent trans-papillary biliary drainage (65 endoscopic and 8 percutaneous) prior to presentation at our institution. 8 of the 73 patients with trans-papillary biliary drainage (11%) presented with and 5 developed cholangitis; all 13 (18%) required subsequent intervention; none of the patients without trans-papillary biliary drainage presented with or required drainage for cholangitis (p = 0.008). Requiring drainage for cholangitis was more likely to delay treatment (p = 0.012) and portended a poorer median overall survival (13.6 months, 95%CI [4.08, not reached)] vs. 20.6 months, 95%CI [18.34, 37.51] p = 0.043). CONCLUSION: Trans-papillary biliary drainage for perihilar cholangiocarcinoma carries a risk of cholangitis and should be avoided when possible. Clinical and imaging findings of perihilar cholangiocarcinoma should prompt evaluation at a cancer referral center before any intervention. This would mitigate development of cholangitis necessitating additional drainage procedures, delaying treatment and potentially compromising survival.

NCCN Guidelines® Insights: Biliary Tract Cancers, Version 2.2023.

In 2023, the NCCN Guidelines for Hepatobiliary Cancers were divided into 2 separate guidelines: Hepatocellular Carcinoma and Biliary Tract Cancers. The NCCN Guidelines for Biliary Tract Cancers provide recommendations for the evaluation and comprehensive care of patients with gallbladder cancer, intrahepatic cholangiocarcinoma, and extrahepatic cholangiocarcinoma. The multidisciplinary panel of experts meets at least on an annual basis to review requests from internal and external entities as well as to evaluate new data on current and emerging therapies. These Guidelines Insights focus on some of the recent updates to the NCCN Guidelines for Biliary Tract Cancers as well as the newly published section on principles of molecular testing.

Summary of key guidelines for locoregional treatment of HCC in Asia, Europe, South and North America.

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide accounting for over 800,000 new cases in 2018, with the highest incidence in Asia and Africa where hepatitis B is the most common risk factor. In Europe, Japan, and the United States, hepatitis C chronic alcohol abuse and non-alcoholic fatty liver disease are more common risk factors. Five-year survival is low, less than 20% worldwide. HCC is a particularly challenging disease to treat because therapeutic options and prognosis must also consider hepatitis or cirrhosis independent of the malignancy. Locoregional therapies (LRT) including ablation, arterially directed therapy and external beam radiation are the preferred treatments for patients with good performance status, unresectable disease limited to the liver and preserved liver function. In practice, patients with portal vein tumor thrombus and limited extrahepatic disease may also be considered candidates for LRT. There are several guidelines developed by expert panels provide recommendations on treating this challenging disease including the Barcelona Clinic Liver Cancer, European Association for the Study of the Liver, European Society for Medical Oncology, American Association for the Study of the Liver Diseases, and the National Comprehensive Cancer Network. The purpose of this paper is to review the guidelines as they are applied clinically in regions with high incidence of HCC.

Biopsy and Margins Optimize Outcomes after Thermal Ablation of Colorectal Liver Metastases.

BACKGROUND: Thermal ablation is a definitive local treatment for selected colorectal liver metastases (CLM) that can be ablated with adequate margins. A critical limitation has been local tumor progression (LTP). METHODS: This prospective, single-group, phase 2 study enrolled patients with CLM < 5 cm in maximum diameter, at a tertiary cancer center between November 2009 and February 2019. Biopsy of the ablation zone center and margin was performed immediately after ablation. Viable tumor in tissue biopsy and ablation margins < 5 mm were assessed as predictors of 12-month LTP. RESULTS: We enrolled 107 patients with 182 CLMs. Mean tumor size was 2.0 (range, 0.6-4.6) cm. Microwave ablation was used in 51% and radiofrequency ablation in 49% of tumors. The 12- and 24-month cumulative incidence of LTP was 22% (95% confidence interval [CI]: 17, 29) and 29% (95% CI: 23, 36), respectively. LTP at 12 months was 7% (95% CI: 3, 14) for the biopsy tumor-negative ablation zone with margins ≥ 5 mm vs. 63% (95% CI: 35, 85) for the biopsy-positive ablation zone with margins < 5 mm (p < 0.001). CONCLUSIONS: Biopsy-proven complete tumor ablation with margins of at least 5 mm achieves optimal local tumor control for CLM, regardless of the ablation modality used.

Percutaneous liver venous deprivation: outcomes in heavily pretreated metastatic colorectal cancer patients.

BACKGROUND: To evaluate liver venous deprivation (LVD) outcomes in patients with colorectal liver metastasis (CRLM) heavily pretreated with systemic and hepatic arterial infusion pump (HAIP) chemotherapies that had an anticipated insufficient future liver remnant (FLR) hypertrophy after portal vein embolization (PVE). METHODS: PVE was performed with liquid embolics using a transsplenic or ipsilateral transhepatic approach. Simultaneously and via a trans-jugular approach, the right hepatic vein was embolized with vascular plugs. Liver volumetry was assessed on computed tomography before and 3-6 weeks after LVD. RESULTS: Twelve consecutive CRLM patients that underwent LVD before right hepatectomy or trisectionectomy were included, all previously treated with systemic chemotherapy for a mean of 11.9 months. Six patients had additional HAIP. After embolization, FLR ratio increased from 28.7% ± 5.9 to 42.2% ± 9.0 (P < 0.01). Mean kinetic growth rate (KGR) was 3.56%/week ± 2.3, with a degree of hypertrophy (DH) of 13.8% ± 7.1. In the HAIP subgroup, mean KGR and DH were respectively 3.58%/week ± 2.8 and 14.3% ± 8.7. No severe complications occurred. Ten patients reached surgery after 39 days ± 7.5. CONCLUSION: In heavily pretreated patients, LVD safely stimulated a rapid and effective FLR hypertrophy, with a resultant high rate of resection.

Treatment of Malignant Bile Duct Obstruction: What the Interventional Radiologist Needs to Know.

Management of malignant bile duct obstruction is both a clinically important and technically challenging aspect of caring for patients with advanced malignancy. Bile duct obstruction can be caused by extrinsic compression, intrinsic tumor/stone/debris, or by biliary ischemia, inflammation, and sclerosis. Common indications for biliary intervention include lowering the serum bilirubin level for chemotherapy, ameliorating pruritus, treating cholangitis or bile leak, and providing access for bile duct biopsy or other adjuvant therapies. In some institutions, biliary drainage may also be considered prior to hepatic or pancreatic resection. Prior to undertaking biliary intervention, it is essential to have high-quality cross-sectional imaging to determine the level of obstruction, the presence of filling defects or atrophy, and status of the portal vein. High bile duct obstruction, which we consider to be obstruction above, at, or just below the confluence (Bismuth classifications IV, III, II, and some I), is optimally managed percutaneously rather than endoscopically because interventional radiologists can target specific ducts for drainage and can typically avoid introducing enteric contents into isolated undrained bile ducts. Options for biliary drainage include external or internal/external catheters and stents. In the setting of high obstruction, placement of a catheter or stent above the ampulla, preserving the function of the sphincter of Oddi, may lower the risk of future cholangitis by preventing enteric contamination of the biliary tree. Placement of a primary suprapapillary stent without a catheter, when possible, is the procedure most likely to keep the biliary tree sterile.

Hepatobiliary Cancers, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology.

The NCCN Guidelines for Hepatobiliary Cancers focus on the screening, diagnosis, staging, treatment, and management of hepatocellular carcinoma (HCC), gallbladder cancer, and cancer of the bile ducts (intrahepatic and extrahepatic cholangiocarcinoma). Due to the multiple modalities that can be used to treat the disease and the complications that can arise from comorbid liver dysfunction, a multidisciplinary evaluation is essential for determining an optimal treatment strategy. A multidisciplinary team should include hepatologists, diagnostic radiologists, interventional radiologists, surgeons, medical oncologists, and pathologists with hepatobiliary cancer expertise. In addition to surgery, transplant, and intra-arterial therapies, there have been great advances in the systemic treatment of HCC. Until recently, sorafenib was the only systemic therapy option for patients with advanced HCC. In 2020, the combination of atezolizumab and bevacizumab became the first regimen to show superior survival to sorafenib, gaining it FDA approval as a new frontline standard regimen for unresectable or metastatic HCC. This article discusses the NCCN Guidelines recommendations for HCC.

NRF2 Dysregulation in Hepatocellular Carcinoma and Ischemia: A Cohort Study and Laboratory Investigation.

Background Intermediate stage hepatocellular carcinomas (HCCs) are treated by inducing ischemic cell death with transarterial embolization (TAE) or transarterial chemoembolization (TACE). A subset of HCCs harbor nuclear factor E2-related factor 2 (NRF2), a major regulator of the oxidative stress response implicated in cell survival after ischemia. NRF2-mutated HCC response to TAE and/or TACE is unknown. Purpose To test whether ischemia resistance is present in individuals with NRF2-mutated HCC and if this resistance can be overcome by means of NRF2 inhibition in HCC cell lines. Materials and Methods This was a combined retrospective review of an institutional database (from January 2011 to December 2018) and prospective study (from January 2014 to December 2018) of participants with HCC who underwent TAE and a laboratory investigation of HCC cell lines. Imaging follow-up included liver CT or MRI at 1 month after the procedure followed by 3-month interval scans. Tumor radiologic response was assessed on the basis of follow-up imaging. The time to local progression after TAE for individuals with and individuals without NRF2 pathway alterations was estimated by using competing risk analysis (Gray test). The in vitro response to ischemia in four HCC cell lines with and without NRF2 overexpression was evaluated, and the combination of ischemia with NRF2 knockdown by means of short hairpin RNA or an NRF2 inhibitor was tested. Doubling time estimates, dose response curve regression, and comparison analyses were performed. Results Sixty-five individuals (median age, 69 years [range, 19-84 years]; 53 men) were evaluated. HCCs with NRF2 pathway mutation had a shorter time to local progression after TAE compared to those without mutation (6-month cumulative incidence of local progression, 56% [range, 19%-91%] vs 22% [range, 12%-34%], respectively; P < .001) and confirmed ischemia resistance in NRF2-overexpressing HCC cell lines. However, ischemia and NRF2 knock-down worked synergistically to decrease proliferation of NRF2-overexpressing HCC cell lines. Dose response curves of ML385, an NRF2 inhibitor, showed that ischemia induces addiction to NRF2 in cells with NRF2 alterations. Conclusion Hepatocellular carcinoma with nuclear factor E2-related factor 2 (NRF2) alterations showed resistance to ischemia, but ischemia simultaneously induced sensitivity to NRF2 inhibition. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Weiss and Nezami in this issue.

Gender Disparity in Industry Relationships With Academic Interventional Radiology Physicians.

OBJECTIVE. Industry relationships drive technologic innovation in interventional radiology and offer opportunities for professional growth. Women are underrepresented in interventional radiology despite the growing recognition of the importance of diversity. This study characterized gender disparities in financial relationships between industry and academic interventional radiologists. MATERIALS AND METHODS. In this retrospective cross-sectional study, U.S. academic interventional radiology physicians and their academic ranks were identified by searching websites of practices with accredited interventional radiology fellowship programs. Publicly available databases were queried to collect each physician's gender, years since medical school graduation, h-index, academic rank, and industry payments in 2018. Wilcoxon and chi-square tests compared payments between genders. A general linear model assessed the impact of academic rank, years since graduation, gender, and h-index on payments. RESULTS. Of 842 academic interventional radiology physicians, 108 (13%) were women. A total $14,206,599.41 was received by 686 doctors (81%); only $147,975.28 (1%) was received by women. A lower percentage of women (74%) than men (83%) received payments (p = 0.04); median total payments were lower for women ($535) than men ($792) (p = 0.01). Academic rank, h-index, years since graduation, and male gender were independent predictors of higher payments. Industry payments supporting technologic advancement were made exclusively to men. CONCLUSION. Female interventional radiology physicians received fewer and lower industry payments, earning 1% of total payments despite constituting 13% of physicians. Gender independently predicted industry payments, regardless of h-index, academic rank, or years since graduation. Gender disparity in interventional radiology physician-industry relationships warrants further investigation and correction.

Safety and Efficacy of Hepatic Artery Embolization in Treating Solitary Fibrous Tumor Metastatic to the Liver.

The aim of this study was to evaluate safety and survival following hepatic artery embolization (HAE) for metastatic solitary fibrous tumor (SFT) in the liver. All patients with SFT metastatic to liver treated with HAE were retrospectively analyzed. Tumor response was evaluated using mRECIST. Objective response, overall survival (OS), and progression-free survival (PFS) were evaluated using Kaplan-Meier and multivariate Cox proportional hazard ratio. Adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0. Twelve patients (6 males and 6 females, mean age: 42.5 ± 13 years; 24-65) were treated with 33 embolizations. Anatomical sites of origin for SFT were the head and neck (n = 6; 50%), pelvis (n = 2), pleura (n = 2), retroperitoneal (n = 1), and thigh (n = 1). The median follow-up from first HAE was 4.5 years (3-7.9). 84% of the patients showed objective response [42% complete response (CR) plus 42% partial response (PR)] to HAE by mRECIST (95% CI, 60-99%). Patients with CR to HAE had significantly higher OS compared to others (p < 0.02). The postembolization median OS was 4 years (95% CI, 2.3-5.2), and mean PFS, for intra- or extrahepatic progression of disease, was 6 months (95%, CI, 3.2-7.1). One patient developed pneumonia/sepsis and died 27 days postembolization, possibly not directly related to embolization. No grade III or IV adverse events were identified in the remaining patients. In conclusion, HAE for metastatic liver SFT is a relatively safe treatment option with high response rate and should be considered as a treatment option for metastatic liver SFT. In our cohort of patients with metastatic SFT to the liver, we observed a median OS of 4 years following HAE. Further studies are needed to confirm the efficacy of HAE.

Incidence and Consequence of Nontarget Embolization Following Bland Hepatic Arterial Embolization.

PURPOSE: Estimate the incidence of nontarget embolization (NTE) as identified on immediate post-hepatic artery embolization CT. MATERIALS AND METHODS: Two hundred hepatic embolizations performed with particles alone (bland embolization) in 147 patients between August 16, 2013 and August 26, 2014 with immediate post-procedure CT were retrospectively reviewed. Arterial anatomy, vessels treated, imaging findings of NTE, patient demographics, length of hospital stay following embolization, and procedure-related complications were recorded. The data were analyzed using two-sided t-tests and chi-squared tests. RESULTS: Evidence of NTE was seen on post-procedure CT in 64 of 200 cases (64/200, 32%). Six organs were affected, with 69 discrete sites in 64 patients. The majority (49/69, 71.0%) involved the gallbladder. The mean length of hospital stay (LOS) for patients with and without NTE was 2.9 ± 1.5 nights (range 1-7) and 2.9 ± 2.3 nights (range 0-21), respectively (P = 0.81). NTE was more common following embolization of replaced or accessory hepatic vessels. There were three complications in the NTE group (3/64, 4.7%) following the embolization procedure, one of which was cholecystitis directly related to NTE. The other two were one incidence each of contrast-induced nephropathy and pneumonia. In the group without NTE, seven complications occurred (7/136, 5.1%, P = 0.889), including one death resulting from hepatic failure, two gastrointestinal bleeds, two hepatic abscesses, flash pulmonary edema, and pancreatitis. CONCLUSION: Unanticipated NTE is not uncommon after bland hepatic artery embolization, particularly after treating accessory or replaced vessels, but does not increase complications or LOS. LEVEL OF EVIDENCE: Level 2b, Retrospective Cohort.

Guidelines Insights: Hepatobiliary Cancers, Version 2.2019.

The NCCN Guidelines for Hepatobiliary Cancers provide treatment recommendations for cancers of the liver, gallbladder, and bile ducts. The NCCN Hepatobiliary Cancers Panel meets at least annually to review comments from reviewers within their institutions, examine relevant new data from publications and abstracts, and reevaluate and update their recommendations. These NCCN Guidelines Insights summarize the panel's discussion and updated recommendations regarding systemic therapy for first-line and subsequent-line treatment of patients with hepatocellular carcinoma.

Endoscopic versus percutaneous drainage of post-operative peripancreatic fluid collections following pancreatic resection.

BACKGROUND: Post-operative peripancreatic fluid collection (PFC) is a common complication following pancreatic resection which can be managed with endoscopic or percutaneous drainage. METHODS: Patients who underwent either endoscopic or percutaneous drainage of post-operative PFC were extracted from a prospectively-maintained database. The two groups were matched for surgery type, presence of a surgical drain and timing of drainage. RESULTS: Thirty-nine matched patients were identified in each group with a median age of 62 years. For primary drainage, technical success was achieved in almost all patients in both endoscopic and percutaneous groups (100% and 97%, p = NS); clinical success was achieved in 67% and 59%, respectively (p = 0.63). At least one "salvage" drainage procedure was required in 13 endoscopic patients versus 16 in the percutaneous group. Clinical success was achieved following the first salvage. Procedure in 85% of the endoscopic patients and 88% of the percutaneous patients (p = 0.62). Stent/drain duration (59 vs 33 days, p < 0.001) and number of post-procedural CT studies (2 vs 1, p = 0.02) were significantly higher in the endoscopic group. There was no difference in length of stay, complication, or recurrence between the two groups. CONCLUSION: Endoscopic drainage of post-operative PFC appears to be safe and effective with comparable success rates and outcomes to percutaneous drainage.

Autologous Blood Patch Injection versus Hydrogel Plug in CT-guided Lung Biopsy: A Prospective Randomized Trial.

Purpose To compare the effect of autologous blood patch injection (ABPI) with that of a hydrogel plug on the rate of pneumothorax at CT-guided percutaneous lung biopsy. Materials and Methods In this prospective randomized controlled trial ( https://ClinicalTrials.gov , NCT02224924), a noninferiority design was used for ABPI, with a 10% noninferiority margin when compared with the hydrogel plug, with the primary outcome of pneumothorax rate within 2 hours of biopsy. A type I error rate of 0.05 and 90% power were specified with a target study population of 552 participants (276 in each arm). From October 2014 to February 2017, all potential study participants referred for CT-guided lung biopsy (n = 2052) were assessed for enrollment. Results The data safety monitoring board recommended the trial be closed to accrual after an interim analysis met prespecified criteria for early stopping based on noninferiority. The final study group consisted of 453 participants who were randomly assigned to the ABPI (n = 226) or hydrogel plug (n = 227) arms. Of these, 407 underwent lung biopsy. Pneumothorax rates within 2 hours of biopsy were 21% (42 of 199) and 29% (60 of 208); chest tube rates were 9% (18 of 199) and 13% (27 of 208); and delayed pneumothorax rates within 2 weeks after biopsy were 1.4% (three of 199) and 1.5% (three of 208) in the ABPI and hydrogel plug arms, respectively. Conclusion Autologous blood patch injection is noninferior to a hydrogel plug regarding the rate of pneumothorax after CT-guided percutaneous lung biopsy. © RSNA, 2018 Online supplemental material is available for this article.

DAXX Mutation Status of Embolization-Treated Neuroendocrine Tumors Predicts Shorter Time to Hepatic Progression.

PURPOSE: To identify common gene mutations in patients with neuroendocrine liver metastases (NLM) undergoing transarterial embolization (TAE) and establish relationship between these mutations and response to TAE. MATERIALS AND METHODS: Patients (n = 51; mean age 61 y; 29 men, 22 women) with NLMs who underwent TAE and had available mutation analysis were identified. Mutation status and clinical variables were recorded and evaluated in relation to hepatic progression-free survival (HPFS) (Cox proportional hazards) and time to hepatic progression (TTHP) (competing risk proportional hazards). Subgroup analysis of patients with pancreatic NLM was performed using Fisher exact test to identify correlation between mutation and event (hepatic progression or death) by 6 months. Changes in mutation status over time and across specimens in a subset of patients were recorded. RESULTS: Technical success of TAE was 100%. Common mutations identified were MEN1 (16/51; 31%) and DAXX (13/51; 25%). Median overall survival was 48.7 months. DAXX mutation status (hazard ratio = 6.21; 95% confidence interval [CI], 2.67-14.48; P < .001) and tumor grade (hazard ratio = 3.05; 95% CI, 1.80-5.17; P < .001) were associated with shorter HPFS and TTHP on univariate and multivariate analysis. Median HPFS was 3.6 months (95% CI, 1.7-5.3) for patients with DAXX mutation compared with 8.9 months (95% CI, 6.6-11.4) for patients with DAXX wild-type status. In patients with pancreatic NLMs, DAXX mutation status was associated with hepatic progression or death by 6 months (P = .024). DAXX mutation status was concordant between primary and metastatic sites. CONCLUSIONS: DAXX mutation is common in patients with pancreatic NLMs. DAXX mutation status is associated with shorter HPFS and TTHP after TAE.

Percutaneous Biliary Interventions.

Biliary drainage is important in the care of patients with benign and malignant biliary obstruction. Careful preprocedure evaluation of high-quality cross-sectional imaging and inventory of symptoms are necessary to determine whether a percutaneous, endoscopic, or surgical approach is most appropriate. High bile duct obstruction is usually best managed percutaneously; a specific duct can be targeted and enteric contamination of isolated ducts can be avoided. Options for percutaneous biliary intervention include external or internal/external biliary drainage, stent placement, biliary stone retrieval, and bile duct biopsy. Preprocedure evaluation, technique, and indications for percutaneous intervention in benign and malignant diseases are summarized.

Hepatocellular Carcinoma: Updates to Screening and Diagnosis.

In what is considered to be "a global problem," liver cancer has tripled in incidence in the United States over the past 20 to 30 years, and is now present in 7 per 100,000 Americans. Thus, screening for disease should be at the forefront to effectively treat high-risk populations. At the 2018 NCCN 23rd Annual Conference, Dr. Anne M. Covey discussed the updated NCCN Guidelines for the screening and diagnosis of hepatocellular carcinoma, which place ultrasound as the most cost-effective and least toxic primary screening option, with a screening interval of approximately 6 months for individuals considered to be at high risk.

Comparison of biliary brush biopsy and fine needle biopsy in the diagnosis of biliary strictures.

PURPOSE: The purpose of this study is to evaluate the accuracy of percutaneous fine needle biopsy (FNB) and brush biopsy (BB) at a cancer center. MATERIAL AND METHODS: Retrospective analysis of all bile duct biopsies performed in Interventional Radiology between January 2000 and January 2015 was performed. FNB was performed under real-time cholangiographic guidance using a notched needle directed at the bile duct stricture. BB was performed by advancing a brush across the stricture and moving it back and forth to scrape the stricture. Biopsy results were categorized as true positive (TP), true negative (TN), false positive (FP) and false negative (FN) based on pathology reports and confirmed by surgical specimens or clinical follow-up of at least six months. Fisher's exact test was used to compare the rate of TP in FNB and BB. RESULTS: One-hundred and nineteen patients underwent FNB or BB. Fifteen were censored because of lack of follow-up. The remaining 104 patients underwent a total of 117 bile duct biopsies during the study period: 34 FNB and 83 BB. There were no complications in either group. In the FNB group 22/34 (64%) biopsies were TP, 4/34(12%) were TN and there were 8(24%) FN biopsies. In the BB group, 20/83 (24%) were TP, 38/83 (46%) TN and 25/83 (30%) FN biopsies. There were no FP biopsies in either group. The sensitivity of detecting malignancy by FNB was significantly higher than that by BB (73% vs 44%, p < .0005). There were no complications associated with FNB or BB. CONCLUSIONS: FNB of bile duct strictures is safe and has a higher sensitivity for detecting malignancy than BB.

Palliative Percutaneous Biliary Interventions in Malignant High Bile Duct Obstruction.

The optimal palliative intervention for malignant biliary obstruction is internal drainage by placement of a metallic stent. For patients with hilar biliary obstruction or low bile duct obstruction in whom endoscopy is not feasible, a percutaneous transhepatic approach in interventional radiology is preferred. This article reviews the rationale for this approach, periprocedural management, and techniques to optimize stent patency.