Two cases of silent subcutaneous implantable cardioverter defibrillator electrode displacement.

We describe two cases of secondary prevention subcutaneous implantable cardioverter defibrillator (S-ICD) implantation and subsequent S-ICD electrode displacement which initially went undetected. One presentation was a result of a coincidental chest x-ray for respiratory exacerbation and another with an untreated episode highlighted via remote monitoring, both patients were booked to clinic for further investigation. Our findings highlighted had there been a comparison of the existing subcutaneous electrogram (S-ECG) to captured S-ECGs at time of implant the electrode displacement would have been detected beforehand. This underpins the importance of introducing the simple management strategy into routine follow-up.

Risk factors affecting long-term efficacy of ultrasound-guided high-intensity focused ultrasound treatment for multiple uterine fibroids.

OBJECTIVES: To investigate the long-term efficacy of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for multiple uterine fibroids and the factors associated with recurrence. MATERIALS AND METHODS: Five hundred and forty-nine patients with multiple uterine fibroids treated with USgHIFU from June 2017 to June 2019 were retrospectively analyzed. The Pictorial Blood Loss Assessment Chart (PBAC) was used to assess menstrual blood loss. The patients were asked to undergo pre- and post-USgHIFU magnetic resonance imaging (MRI) and complete routine follow-up after USgHIFU. Cox regression analysis was used to investigate the risk factors associated with recurrence. RESULTS: The median number of fibroids per patient was 3 (interquartile range: 3-4), and a total of 1371 fibroids were treated. Among them, 446 patients completed 3 years follow-up. Recurrence, defined as PBAC score above or equal to 100 and/or the residual fibroid volume increased by 10%, was detected in 90 patients within 3 years after USgHIFU, with a cumulative recurrence rate of 20.2% (90/446). The multi-factor Cox analysis showed that age was a protective factor for recurrence. Younger patients have a greater chance of recurrence than older patients. Mixed hyperintensity of fibroids on T2WI and treatment intensity were risk factors for recurrence. Patients with hyperintense uterine fibroids and treated with lower treatment intensity were more likely to experience recurrence than other patients after USgHIFU. No major adverse effects occurred. CONCLUSIONS: USgHIFU can be used to treat multiple uterine fibroids safely and effectively. The age, T2WI signal intensity and treatment intensity are factors related to recurrence.

Long-term re-intervention after USgHIFU and prediction of NPVR in different ages of patients with uterine fibroids.

OBJECTIVE: Long-term re-intervention after ultrasound-guided high intensity focused ultrasound (USgHIFU) ablation was reported, and the prediction of non-perfusion volume ratio (NPVR) in differently aged patients with uterine fibroids (UFs) was explored. MATERIALS AND METHODS: Patients with UFs who underwent USgHIFU ablation from January 2012 to December 2019 were enrolled and divided into < 40-year-old and ≥ 40-year-old groups. Cox regression was used to analyze the influencing factors of re-intervention rate, and receiver operating characteristic (ROC) curve was used to analyze the correlation between NPVR and re-intervention rate. RESULTS: A total of 2141 patients were enrolled, and 1558 patients were successfully followed up. The 10-year cumulative re-intervention rate was 21.9%, and the < 40-year-old group had a significantly higher rate than the ≥ 40-year-old group (30.8% vs. 19.1%, p < 0.001). NPVR was an independent risk factor in both two groups. When the NPVR reached 80.5% in the < 40-year-old group and 75.5% in the ≥ 40-year-old group, the risk of long-term re-intervention was satisfactory. CONCLUSION: The long-term outcome of USgHIFU is promising. The re-intervention rate is related to NPVR in differently aged patients. Young patients need a high NPVR to reduce re-intervention risk.

Achieving NPVR ≥ 80% as technical success of high-intensity focused ultrasound ablation for uterine fibroids: a cohort study.

OBJECTIVE: To report the long-term re-intervention of patients with uterine fibroids after ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation and to analyse the influencing factors of re-intervention in patients in the NPVR ≥ 80% group. MATERIALS AND METHODS: Patients with a single uterine fibroid who underwent USgHIFU at our hospital from January 2012 to December 2019 were enrolled. The patients were divided into four groups according to different nonperfusion volume ratio (NPVR). Kaplan-Meier survival curve was used to analyse long-term re-intervention in different NPVR groups, and Cox regression was used to analyse the influencing factors of re-intervention in the NPVR ≥ 80% group. MAIN RESULTS: A total of 1,257 patients were enrolled, of whom 920 were successfully followed up. The median follow-up time was 88 months, and the median NPVR was 85.0%. The cumulative re-intervention rates at 1, 3, 5, 8 and 10 years after USgHIFU were 3.4%, 11.8%, 16.8%, 22.6% and 24.1%, respectively. The 10-year cumulative re-intervention rate was 37.3% in the NPVR < 70% group, 31.0% in the NPVR 70-79% group, 18.2% in the NPVR 80-89% group and 17.8% in the NPVR ≥ 90% group (P < 0.05). However, no difference was found between the group of NPVR 80-89% and the group of NPVR ≥ 90% (P = 0.499). Age of patients and signal intensity on T2-weighted imaging (T2WI) of tumours were found to be independent risk factors for long-term re-intervention in the NPVR ≥ 80% group. A younger age and greater signal intensity on T2W images corresponded to a greater risk of re-intervention. CONCLUSION: USgHIFU, an alternative treatment for uterine fibroids, has reliable long-term efficacy. NPVR ≥ 80% can be used as a sign of technical success, which can reduce re-intervention rates. However, an important step is to communicate with patients in combination with the age of patients and the signal intensity on T2WI of fibroids. TRIAL REGISTRATION: This retrospective study was approved by the ethics committee at our institution (Registration No. HF2023001; Date: 06/04/2023). The Chinese Clinical Trial Registry provided full approval for the study protocol (Registration No. CHiCTR2300074797; Date: 16/08/2023).

Physician-modified inner-branched endovascular repair with re-intervention.

OBJECTIVES: Treatment of thoracoabdominal aortic aneurysms in high surgical risk patients can be challenging. Reports of physician-modified inner-branched endovascular repair (PMiBEVAR) are increasing. Despite low morbidity and mortality rates, re-interventions for endoleaks with these grafts are serious. There are no reports of additional treatment for PMiBEVAR failure. METHODS/RESULTS: A 75-year-old man presented to our hospital with a Crawford's type IV thoracoabdominal aortic aneurysm. A PMiBEVAR was performed. Postoperative computed tomographic angiography revealed an endoleak from the inner branch of the right renal artery. A re-intervention was performed with coil embolization of the endoleak. Imaging after re-intervention showed successful obliteration of the endoleak. CONCLUSIONS: We thereby report a successful case of re-intervention for PMiBEVAR failure.

Prosthetic Valve Endocarditis After Aortic Valve Replacement: Differences Between Biological and Mechanical Prostheses.

AIMS: Prosthetic valve endocarditis (PVE) is the most severe form of infective endocarditis associated with a high mortality rate. Whether PVE affects biological and mechanical aortic valves to the same extent remains controversial. This study aimed to compare the incidence of re-intervention because of PVE between bioprosthetic and mechanical valves. METHODS: Patients undergoing isolated surgical aortic valve replacement (AVR) or combined AVR in a single cardiac surgery centre between January 1998 and December 2019 were analysed. All patients who underwent re-intervention because of PVE were identified. The primary endpoint was the rate of explants. Freedom from re-intervention and variables associated with re-intervention were analysed using Cox regression analysis including correction for competing risk. RESULTS: During the study period, 5,983 aortic valve prostheses were implanted, including 3,620 biological (60.5%) and 2,363 mechanical (39.5%) prostheses. The overall mean follow-up period was 7.3±5.3 years (median, 6.5; IQR 2.9-11.2 years). The rate of re-intervention for PVE in the biological group was 1.5% (n=54) compared with 1.7% (n=40) in the mechanical group (p=0.541). Cox regression analysis revealed that younger age (HR 0.960, 95% CI 0.942-0.979; p<0.001), male sex (HR 2.362, 95% CI 1.384-4.033; p=0.002), higher creatinine (HR 1.002, 95% CI 0.999-1.004; p=0.057), and biological valve prosthesis (HR 2.073, 95% CI 1.258-3.414; p=0.004) were associated with re-intervention for PVE. After correction for competing risk of death, biological valve prosthesis was significantly associated with a higher rate of re-intervention for PVE (HR 2.011, 95% CI 1.177-3.437; p=0.011). CONCLUSIONS: According to this single-centre, observational, retrospective cohort study, AVR using biological prosthesis is associated with re-intervention for PVE compared to mechanical prosthesis. Further investigations are needed to verify these findings.

Clinical Course of TGA After Arterial Switch Operation in the Current Era.

Background: The number of patients with an arterial switch operation (ASO) for transposition of the great arteries (TGA) is steadily growing; limited information is available regarding the clinical course in the current era. Objectives: The purpose was to describe clinical outcome late after ASO in a national cohort, including survival, rates of (re-)interventions, and clinical events. Methods: A total of 1,061 TGA-ASO patients (median age 10.7 years [IQR: 2.0-18.2 years]) from a nationwide prospective registry with a median follow-up of 8.0 years (IQR: 5.4-8.8 years) were included. Using an analysis with age as the primary time scale, cumulative incidence of survival, (re)interventions, and clinical events were determined. Results: At the age of 35 years, late survival was 93% (95% CI: 88%-98%). The cumulative re-intervention rate at the right ventricular outflow tract and pulmonary branches was 36% (95% CI: 31%-41%). Other cumulative re-intervention rates at 35 years were on the left ventricular outflow tract (neo-aortic root and valve) 16% (95% CI: 10%-22%), aortic arch 9% (95% CI: 5%-13%), and coronary arteries 3% (95% CI: 1%-6%). Furthermore, 11% (95% CI: 6%-16%) of the patients required electrophysiological interventions. Clinical events, including heart failure, endocarditis, and myocardial infarction occurred in 8% (95% CI: 5%-11%). Independent risk factors for any (re-)intervention were TGA morphological subtype (Taussig-Bing double outlet right ventricle [HR: 4.9, 95% CI: 2.9-8.1]) and previous pulmonary artery banding (HR: 1.6, 95% CI: 1.0-2.2). Conclusions: TGA-ASO patients have an excellent survival. However, their clinical course is characterized by an ongoing need for (re-)interventions, especially on the right ventricular outflow tract and the left ventricular outflow tract indicating a strict lifelong surveillance, also in adulthood.

Decreased clinical performance in TGA-ASO patients after RVOT interventions; a multicenter European collaboration.

BACKGROUND: In patients with transposition of the great arteries and an arterial switch operation (TGA-ASO) right ventricular outflow tract (RVOT) obstruction is a common complication requiring one or more RVOT interventions. OBJECTIVES: We aimed to assess cardiopulmonary exercise capacity and right ventricular function in patients stratified for type of RVOT intervention. METHODS: TGA-ASO patients (≥16 years) were stratified by type of RVOT intervention. The following outcome parameters were included: predicted (%) peak oxygen uptake (peak VO2), tricuspid annular plane systolic excursion (TAPSE), tricuspid Lateral Annular Systolic Velocity (TV S'), right ventricle (RV)-arterial coupling (defined as TAPSE/RV systolic pressure ratio), and N-terminal proBNP (NT-proBNP). RESULTS: 447 TGA patients with a mean age of 25.0 (interquartile range (IQR) 21-29) years were included. Patients without previous RVOT intervention (n = 338, 76%) had a significantly higher predicted peak VO2 (78.0 ± 17.4%) compared to patients with single approach catheter-based RVOT intervention (73.7 ± 12.7%), single approach surgical RVOT intervention (73.8 ± 28.1%), and patients with multiple approach RVOT intervention (66.2 ± 14.0%, p = 0.021). RV-arterial coupling was found to be significantly lower in patients with prior catheter-based and/or surgical RVOT intervention compared to patients without any RVOT intervention (p = 0.029). CONCLUSIONS: TGA patients after a successful arterial switch repair have a decreased exercise capacity. A considerable amount of TGA patients with either catheter or surgical RVOT intervention perform significantly worse compared to patients without RVOT interventions.

Reintervenciones tras apendicectomía en niños. Estudio multicéntrico / Re-interventions following appendectomy in children: a multicenter study

Introducción: La apendicitis aguda es la causa más frecuente deabdomen agudo en niños. El objetivo de este trabajo es estudiar lascausas, abordaje y resultados de las complicaciones que requieren in-tervención quirúrgica después de la apendicectomía.Material y métodos: Estudio retrospectivo de las apendicectomíasrealizadas en 3 centros de tercer nivel entre 2015-2019. Se recogieronlas complicaciones, causas y número de reintervenciones, intervalo entreambas cirugías, técnica empleada, hallazgos operatorios según la Clasi-ficación de la American Association for the Surgery of Trauma (AAST)en la apendicectomía inicial y tiempo de ingreso.Resultados: Se intervinieron 3.698 apendicitis, un 76,7% por víalaparoscópica, encontrando un 37,2% evolucionadas (grado II-V de laclasificación AAST). El tiempo medio quirúrgico fue de 50,4 minutos(laparoscopia 49,8 ± 20,1 vs. laparotomía 49,9 ± 20,1, p > 0,05), superioren aquellos pacientes que requirieron reintervención (68,6 ± 27,2 vs.49,1 ± 19,3, p < 0,001).Se realizaron 76 reintervenciones (2,05%). Las causas fueron: infec-ción postoperatoria (n = 46), obstrucción intestinal (n = 20), dehiscencia(n = 4) y otras (n = 6). El abordaje inicial no influyó en el riesgo dereintervención (laparotomía o laparoscopia, OR 1,044, IC 95% 0,57-1,9),pero sí el grado de evolución de la apendicitis (7,8% evolucionadas vs.0,7% incipientes, OR 12,52, IC 95% 6,18-25,3).Hubo una tendencia a reintervenir por el mismo abordaje que laapendicectomía, esto ocurrió en un 72,2% de las apendicectomías lapa-roscópicas y en un 67,7% de las apendicectomías abiertas. El abordajemínimamente invasivo (50/76) fue más frecuente que la laparotomía(27 laparoscopias y 23 drenajes ecoguiados frente a 26 laparotomías)(p < 0,05). El 55% de los pacientes obstruidos se reintervinieron porvía abierta (p > 0,05).

Introduction: Acute appendicitis is the most frequent cause ofacute abdomen in children. The objective of this study was to analyzethe causes, approach, and results of complications requiring surgeryfollowing appendectomy.Materials and methods: A retrospective study of the appendecto-mies conducted in three third-level institutions from 2015 to 2019 wascarried out. Complications, causes, and number of re-interventions, timefrom one surgery to another, surgical technique used, operative findingsat baseline appendectomy according to the American Association forthe Surgery of Trauma (AAST) classification, and hospital stay werecollected.Results: 3,698 appendicitis cases underwent surgery, 76.7%of which laparoscopically, with 37.2% being advanced (grades II-Vof the AAST classification). Mean operating time was 50.4 min-utes (49.8 ± 20.1 for laparoscopy vs. 49.9 ± 20.1 for open surgery,p > 0.05), and longer in patients requiring re-intervention (68.6 ± 27.2vs. 49.1 ± 19.3, p < 0.001).76 re-interventions (2.05%) were carried out. The causes includedpostoperative infection (n = 46), intestinal obstruction (n = 20), dehis-cence (n = 4), and others (n = 6). Re-intervention risk was not impactedby the baseline approach used (open surgery or laparoscopy, OR: 1.044,95% CI: 0.57-1.9), but it was by appendicitis progression (7.8% ad-vanced vs. 0.7% incipient, OR: 12.52, 95% CI: 6.18-25.3).There was a tendency to use the same approach both at baseline ap-pendectomy and re-intervention. This occurred in 72.2% of laparoscopicappendectomies, and in 67.7% of open appendectomies. The minimallyinvasive approach (50/76) was more frequent than the open one (27laparoscopies and 23 ultrasound-guided drainages vs. 26 open surger-ies) (p < 0.05). 55% of obstruction patients underwent re-interventionthrough open surgery (p > 0.05).

Follow-up and further intervention for postoperative pulmonary venous obstruction of total anomalous pulmonary venous connection / 中华胸心血管外科杂志

Objective:Postoperative venous obstruction (PVO) is the most severe complication of total anomalous pulmonary venous connection (TAPVC), and facing challenging re-intervention with high mortality. We aimed to review and analyze the follow-up and management of postoperative PVO in our center.Methods:We conducted a retrospective study of the patients with isolated TAPVC admitted in our center from October 2013 to October 2019. All available data and images of PVO patients were reviewed, such as the initial perioperative medical records, patients’ follow-up records, results of patients’ echo and CT angiography. Re-intervention including hybrid technique, sutureless technique, and patch augmentation, were carried out for postoperative PVO patients. The results were reviewed and analyzed to find the risk factors for adverse prognosis.Results:A series of 174 isolated TAPVC patients were admitted in our center and 169 received surgical treatment and 26 (26/169, 15.4%) had postoperative PVO. The diagnosis was made at a median time of 11.5 (0-77) weeks after initial operation and within 6 months of surgery in 22 (22/26, 84.6%) of the 26 patients. The subtype of TAPVC patients with postoperative PVO were: supracardiac 11 cases (11/26, 42.3%), cardiac 7 cases (7/26, 26.9%), infracardiac 5 cases (5/26, 19.2%), and mixed 3 cases (3/26, 11.5%). Bilateral obstruction and stenosis with diffusely small pulmonary veins were in 12 (12/26, 46.2%) and 3 cases (3/26, 11.5%) respectively. PVO progressed to worse condition in all the 26 cases during follow-up period. 8 (8/26, 30.8%) postoperative PVO patients underwent 10 re-interventions: one cases had 3 re-interventions. Five-year survival for patients with postoperative PVO was worse than those without postoperative PVO ( HR=6.46, 95% CI: 2.34-17.85, P<0.01). Risk factors for death or re-intervention in postoperative PVO patients were earlier presentation after TAPVC repair ( HR=0.85, 95% CI: 0.73-0.99, P=0.04) and an increased number of lung segments affected by obstruction ( HR=1.74, 95% CI: 1.01-2.99, P=0.04). Conclusion:Risk factors for death or re-intervention in postoperative PVO patients were earlier presentation after TAPVC repair and an increased number of lung segments affected, which should be focused on during strict follow-up period. Early re-intervention should be taken before irreversible secondary changes occur in these patients.

Unplanned re-intervention within 30 days after pediatric cardiac surgery / 中国胸心血管外科临床杂志

@#Objective     To recognize the risk factors of unplanned re-interventions within 30 days after pediatric cardiac surgery and evaluate the outcome of re-interventions. Methods     We retrospectively analyzed the clinical data of 202 children in Fuwai Hospital between January 1, 2015 and August 31, 2017. There were 115 males and 87 females at average age of 32.4 months with range of 3 days to 14 years. Results     There were 202 children who underwent unplanned re-intervention during 30 days post-operation, including 54 re-adjustments of pulmonary blood flow, 34 re-corrections for residual cardiac abnormalities, 28 cardiopulmonary resuscitations, 38 for coagulation problems, 19 pericardial drainages, 11 palliative re-operations to deliver heart load and 6 diaphragmatic folds and 12 others. The mortality rate among children who underwent unplanned re-inventions after cardiac surgery was 10.9% (22/202). It was much higher than those free from re-interventions (0.7%). Time of mechanical ventilation was 284.3 (11–2 339) h, and mean ICU stay was 17.7 (1–154) d, significantly longer than those free from re-interventions at the same period. Conclusion     Unplanned re-interventions after pediatric cardiac surgery is associated with higher mortality rate and longer recovery time. Early identifying risk factors and re-intervention can reduce the complications and improve the prognosis.

Late open conversion in ruptured abdominal aortic aneurysm after endovascular repair / Conversão tardia para cirurgia aberta em um aneurisma roto da aorta abdominal após reparo endovascular

Abstract Despite technological advances, the long-term outcomes of endovascular aortic aneurysm repair (EVAR) are still debatable. Although most endograft failures after EVAR can be corrected with endovascular techniques, open conversion may still be required. A 70-year-old male patient presented at the emergency unit with abdominal pain. Twice, in the third and fourth years after the first repair, a stent graft had been placed over a non-adhesive portion of the stent graft due to type Ia endoleaks. In the most recent admission, a CT scan showed type III endoleak and ruptured aneurysm sac. On this occasion the patient underwent late open conversion. The failure was repaired with total preservation of the main endovascular graft body and interposition of a bifurcated dacron graft. This case demonstrates that lifelong radiographic surveillance should be considered in this subset of patients. Late open conversion following EVAR of ruptured abdominal aortic aneurysms can be performed safely.

Resumo Apesar dos avanços tecnológicos, os desfechos de longo prazo do reparo endovascular de aneurismas da aorta abdominal (endovascular aortic aneurysm repair - EVAR) ainda são objeto de debate. Embora a maioria das falhas de endoenxerto após EVAR possam ser corrigidas com técnicas endovasculares, conversão para cirurgia aberta ainda pode ser necessária. Um paciente de 70 anos de idade, do sexo masculino, apresentou-se no serviço de emergência com dor abdominal. Duas vezes, dois e quatro anos após o primeiro reparo, um enxerto foi colocado sobre uma porção não adesiva do stent devido a endoleak tipo Ia. Na mais recente hospitalização, a tomografia computadorizada mostrou endoleak tipo III e ruptura de um saco aneurismático. Nesta ocasião, o paciente foi submetido a conversão tardia para cirurgia aberta. A falha foi tratada com preservação total do corpo principal do enxerto endovascular e interposição de um enxerto tipo Dacron bifurcado. Este caso demonstra que a vigilância radiográfica ao longo de toda a vida deveria ser considerada nesse subgrupo de pacientes. Conversão tardia para cirurgia aberta após EVAR de aneurismas rotos da aorta abdominal pode ser realizada com segurança.

How Long Can the Next Intervention Be Delayed after Balloon Dilatation of Homograft in the Pulmonary Position?

BACKGROUND AND OBJECTIVES: We investigated the effectiveness of balloon dilatation of homograft conduits in the pulmonary position in delaying surgical replacement. SUBJECTS AND METHODS: We reviewed the medical records of patients who underwent balloon dilatation of their homograft in the pulmonary position from 2001 to 2015. The pressure gradient and ratio of right ventricular pressure were measured before and after the procedure. The primary goal of this study was to evaluate the parameters associated with the interval to next surgical or catheter intervention. RESULTS: Twenty-eight balloon dilations were performed in 26 patients. The median ages of patients with homograft insertion and balloon dilatation were 20.3 months and 4.5 years, respectively. The origins of the homografts were the aorta (53.6%), pulmonary artery (32.1%), and femoral vein (14.3%). The median interval after conduit implantation was 26.7 months. The mean ratio of balloon to graft size was 0.87. The pressure gradient through the homograft and the ratio of right ventricle to aorta pressure were significantly improved after balloon dilatation (p<0.001). There were no adverse events during the procedure with the exception of one case of balloon rupture. The median interval to next intervention was 12.9 months. The median interval of freedom from re-intervention was 16.6 months. Cox proportional hazards analysis revealed that the interval of freedom from re-intervention differed only according to origin of the homograft (p=0.032), with the pulmonary artery having the longest interval of freedom from re-intervention (p=0.043). CONCLUSION: Balloon dilatation of homografts in the pulmonary position can be safely performed, and homografts of the pulmonary artery are associated with a longer interval to re-intervention.

A Case of Open Surgery for Endoleak after Thoracic Endovascular Aortic Repair of the Aortic Arch / 日本心臓血管外科学会雑誌

A 72-year-old woman underwent thoracic endovascular aortic repair (TEVAR) for an aortic arch aneurysm at a previous hospital. During follow-up, although the aneurysm was found to have become bigger, no further treatments were given, except for conservative follow-up. The patient sought a second opinion and thus visited our hospital. Enhanced computed tomography (CT) revealed a type I endoleak that required repair. Total arch replacement with removal of the partial stent-graft system was performed under deep hypothermic circulatory arrest. The patient made a steady progress postoperatively and was discharged without any complications. Endovascular repair is minimally invasive and frequently used in various medical facilities but carries a considerably high risk of reintervention. Treatment strategies for aortic aneurysm, including open surgery, should be carefully chosen.

Recent Advances of Biliary Stent Management

Recent progress in chemotherapy has prolonged the survival of patients with malignant biliary strictures, leading to increased rates of stent occlusion. Even we employed metallic stents which contributed to higher rates and longer durations of patency, and occlusion of covered metallic stents now occurs in about half of all patients during their survival. We investigated the complication and patency rate for the removal of covered metallic stents, and found that the durations were similar for initial stent placement and re-intervention. In order to preserve patient quality of life, we currently recommend the use of covered metallic stents for patients with malignant biliary obstruction because of their removability and longest patency duration, even though uncovered metallic stents have similar patency durations.