Pigtail Suture Stents Significantly Reduce Stent-related Symptoms Compared to Conventional Double J Stents: A Prospective Randomized Trial

Ureteral stents: What your eyes can't see! An in vitro study

OBJECTIVES

To characterize and compare in vitro the surfaces of ureteral stents (STENTS) before utilization.

METHODS

Our in vitro experiment included six unused STENTS models: three double-pigtail with side orifices (ImaJin and Stenostent [Coloplast©,France], TriaSoft [BostonScientific©,USA]), two double-pigtail without side orifice (Vortek-TumorStent [Coloplast©,France], Urosoft-TumorStent [Bard-Angiomed©,Germany]) and one single-pigtail (J-Fil [Rocamed©,Monaco]). STENTS were made of polyurethane except for ImaJin (silicone). For all STENTS, four parts of the stent were specifically analyzed under high-resolution scanning electron microscopy (HR-SEM,FEI-XL40 [Philips©,France]): surface core, lateral orifice, ureteral loop, and black marking surface. Each experiment was repeated with three different samples from three different stents. STENTS analysis included multiple imperfection searches, defined as irregularities>10μm.

RESULTS

All STENTS presented imperfections with no discernible differences. Imperfections were mainly located on the stent loop and on the lateral orifice. For STENTS without side orifice (J-Fil, Urosoft) imperfections were also reported, on the beveled cut as well as the distal loop orifice. Marking surfaces examinations found defects in the Urosoft and imperfections in the ImaJin and Stenostent. The Triasoft presented a better smoothness on marking surfaces compared to other STENTS. Additional matter was reported on the loop distal orifice for J-Fil and ImaJin but all STENTS presented irregular cross-sectional aeras.

CONCLUSION

All ureteral stents are not perfectly smooth even before utilization. Imperfections were noticed regardless to stent composition or shape, and could play a role in the incrustation phenomenon, is association with inner irregularities, infection, and urine composition. Both manufacturing and material could have an impact on the stent external surface's smoothness.

LEVEL OF EVIDENCE: 3

Novel Antireflux "RELIEF" Stent to Prevent Vesicoureteral Reflux

OBJECTIVE

To assess efficacy, comfort, and symptoms of a novel ureteral stent (RELIEF) substituting the distal semirigid coil of a traditional double-J for a floating, monofilament tether allowing coaptation of the ureteral orifice. Ureteral instrumentation notoriously cause discomfort, urgency, frequency, dysuria, and hematuria; prolonged morbidity is likely related to stent-associated vesicoureteral reflux (VUR). We hypothesized this design would eliminate VUR, be safe and provide comfort following intervention.

METHODS

Twenty-eight patients within a single institution were enrolled. Passive cystography was performed pre- and post-stent placement assessing VUR. Patients completed Ureteric Stent Symptoms Questionnaires (USSQ) before placement (baseline), postop day 1, and day of removal.

RESULTS

Twenty RELIEF stents were placed (11 female and 9 male). 95% demonstrated no VUR following placement. No unexpected adverse complications occurred; 1 patient opted for early stent removal for significant discomfort. Average total USSQ scores demonstrated statistically significant improvement between first and third surveys (P < .001). Statistically significant improvement in body pain, general health, and work performance scores were noted as well (P < .05).

CONCLUSION

The RELIEF stent eliminates VUR with similar stent-related morbidity and overall well-tolerance. RELIEF-associated USSQ scores were below published mean symptom scores for standard double-J stents and appear safe in this preliminary clinical trial.

Prevention of complications in endourological management of stones: What are the basic measures needed before, during, and after interventions?

Objective

This narrative review aims to describe measures to minimise the risk of complications during percutaneous nephrolithotomy (PCNL), ureteroscopy, and retrograde intrarenal surgery.

Methods

A literature search was conducted from the PubMed/PMC database for papers published within the last 10 years (January 2012 to December 2022). Search terms included "ureteroscopy", "retrograde intrarenal surgery", "PCNL", "percutaneous nephrolithotomy", "complications", "sepsis", "infection", "bleed", "haemorrhage", and "hemorrhage". Key papers were identified and included meta-analyses, systematic reviews, guidelines, and primary research. The references of these papers were searched to identify any further relevant papers not included above.

Results

The evidence is assimilated with the opinions of the authors to provide recommendations. Best practice pathways for patient care in the pre-operative, intra-operative, and post-operative periods are described, including the identification and management of residual stones. Key complications (sepsis and stent issues) that are relevant for any endourological procedure are then be discussed. Operation-specific considerations are then explored. Key measures for PCNL include optimising access to minimise the chance of bleeding or visceral injury. The role of endoscopic combined intrarenal surgery in this regard is discussed. Key measures for ureteroscopy and retrograde intrarenal surgery include planning and technique to minimise the risk of ureteric injury. The role of anaesthetic assessment is discussed. The importance of specific comorbidities on each step of the pathway is highlighted as examples.

Conclusion

This review demonstrates that the principles of meticulous planning, interdisciplinary teamworking, and good operative technique can minimise the risk of complications in endourology.

Patients undergoing double J substitution with a pigtail suture stent report a significant decrease of stent-related symptoms. Results from a prospective multicenter longitudinal trial

PURPOSE

To compare stent-related symptoms (SRS) in patients with double J (DJ) undergoing substitution with a pigtail suture stent (PSS) after ureteroscopy (URS), through the Ureteral Stent Symptom Questionnaire (USSQ).

MATERIALS AND METHODS

Patients with DJ undergoing URS for stone treatment were enrolled in this prospective multicenter longitudinal study. The USSQ was submitted thrice: 2 weeks after DJ, 2 weeks after PSS and 4 weeks after PSS removal (baseline).

PRIMARY ENDPOINT

to compare Urinary Symptom Index Score and the rate of patients with pain 2 weeks after DJ and PSS. Secondary endpoints: to compare other USSQ scores and single answers 2 weeks after DJ and PSS, and DJ and PSS USSQ scores with baseline.

RESULTS

93 patients were enrolled. 2 weeks Urinary Symptom Index Score (p < 0.001) and the percentage of patients complaining of pain (60.2% vs 88.2%, p < 0.001) were significantly in favour of PSS compared to DJ. 2 weeks scores were significantly improved with PSS compared to DJ: Pain Index (p < 0.001), VAS (p < 0.001), General Health Index (p < 0.001) and Work Performance Index (p < 0.001). All urinary symptoms were significantly decreased with PSS, including renal pain during micturition and pain interfering with life. Pain Index Score (p = 0.622) and VAS (p = 0.169) were comparable to baseline with PSS, while differed with DJ.

CONCLUSIONS

Patients undergoing DJ substitution with PSS after URS report a significant decrease of SRS. Urologists may consider positioning PSS after URS in pre-stented patients to reduce the impact of SRS.

Suture Stenting After Sialendoscopy: A Novel Technique That Reduces Risk of Recurrent Parotitis

OBJECTIVE

Chronic sialadenitis is associated with decreased quality of life and recurrent infections. While sialendoscopy with stenting is effective in relieving symptoms of sialadenitis, currently available stents are rigid and poorly tolerated by patients, leading to early removal and potential for adverse scarring. This study examines whether sutures can be used as a stenting material to improve patient comfort and reduce recurrence risk.

METHODS

This is a retrospective cohort study of a consecutive series of adult patients with chronic sialadenitis undergoing sialendoscopy with or without suture stenting. Data were collected between 2014 and 2018 with a 3-year follow-up period ending in 2021. The primary outcome measure was recurrence of sialadenitis within 3 years of surgery. Secondary outcomes were stent dislodgement and patient-reported discomfort.

RESULTS

We included 63 patients with parotid sialadenitis of whom 28 underwent suture stenting and 35 did not receive stenting after sialendoscopy. Stents were well tolerated, with a mean duration of 34.5 days, and only 2 of 28 stents (7.1%) accidentally dislodged within the first week. Suture stenting significantly reduced symptom recurrence after sialendoscopy (OR = 0.09, 95% CI 0.02-0.45, p = 0.003; 3-year sialadenitis recurrence rate: 7.1% vs. 45.7%, p = 0.005). Cox multivariate regression for clinicodemographic variables showed an HR of 0.04 (95% CI 0.01-0.19, p < 0.001) for the risk of symptom recurrence.

CONCLUSIONS AND RELEVANCE

Suture stenting after sialendoscopy is low cost, available across all institutions, well-tolerated by patients, and highly efficacious in reducing risk of recurrent sialadenitis after sialendoscopy.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:614-621, 2024.

Catheter-Free Urodynamics Testing: Current Insights and Clinical Potential

Lower urinary tract dysfunction not only interferes with the health-related quality of life of patients but may also lead to acute kidney injury and infections. To assess the bladder, urodynamic studies (UDS) have been implemented but the use of catheters leads to discomfort for the patient. Catheter-free long-term UDS would be useful and a potential solution could be ambulatory wireless devices that communicate via telemetry. Such sensors can detect pressure or volume. Numerous types of potential catheter-free sensors have been proposed for bladder monitoring. Despite substantial innovation in the manufacturing of implantable biomedical electronic systems, such sensors have remained at the laboratory stage due to a number of critical challenges. These challenges primarily concern hermeticity and biocompatibility, sensitivity and artifacts, drift, telemetry, and energy management. Having overcome these challenges, catheter-free ambulatory urodynamic monitoring could combine a synchronized intravesical pressure sensor with a volume analyzer but only the steps of cystometry and volume measurement are currently sufficiently reproducible to simulate UDS results. The measurement of volume by infrared optical sensors, in the form of abdominal patches, appears to be promising and studies are underway to market a telemetric ambulatory urodynamic monitoring system that includes an intravesical pressure sensor. There has been considerable progress in wearable and conformable electronics on many fronts, and continued collaboration between engineers and urologists could quickly overcome current challenges. In addition, to the diagnosis of UDS, such sensors could be useful in the development of a long-term closed-loop neuromodulation system. In this review, we explore the various types of catheter-free bladder sensors, inherent challenges and solutions to overcome these challenges, and the clinical potential of such long-term implantable sensors.

Comparation of intraureteral stent and conventional stent at different stages: a systematic review with meta-analysis

INTRODUCTION

Stent related symptom (SRS) is the most common adverse effect of ureteral stenting. In recent years, many efforts have been made to develope modified ureteral stents to ameliorate SRS. It has been reported that intraureteral stents have the potential to improve the tail end adverse effect of the bladder and alleviate SRS. However, there still lack of evidence for the efficacy and the safety of clinically applying intraureteral stents. The aim of this work is to investigate the efficacy and safety of intraureteral stents.

EVIDENCE ACQUISITION

A systematic review was performed by using the PubMed, Web of Science, Medline, Embase, and Cochrane library. The studies published before February 2023 were included. The study selection was following the guideline from Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). The searching strategy was: "Pigtail suture stent" OR "Intra-ureteric stent" OR "Suture Stent" OR "Intraureteral stent" AND "Ureteroscopy" OR "Urinary calculi" OR "Stent-related symptoms" OR "Lower urinary tract symptoms". The data from randomized clinical trials which meet the selection criteria were extracted. Revman 5.4 was employed to proceed the meta-analysis.

EVIDENCE SYNTHESIS

A total of six randomized clinical trials of intraureteral stents were included in this systematic review and meta-analysis. According to the different investigation time, the results could be divided into four stages: early-stage, middle-stage, late-stage, and long-term evaluation. Urinary symptoms, pain score, and general health were significantly improved in intraureteral stents group at middle stage. For late-stage, intraureteral stent achieved better outcomes in urinary symptoms index, VAS score, quality of life, general health, and pain score. However, for early-stage and long-term evaluation, there was no significant difference between two groups.

CONCLUSIONS

This systematic review and meta-analysis reveal that regardless of the stage of treatment, the efficacy and safety of intraureteral stent are no worse than that of conventional stent. During 7-14 days postoperation, which is the most commonly time for clinically using ureteral stent, most of the outcomes of intraureteral stent are better than those of conventional stent. Hence, it is confirmed that intraureteral stent is worth for more clinical study and application.

Allium® ureteral stent, a new player in the treatment of ureteral stenosis: a prospective cohort study

INTRODUCTION AND OBJECTIVES

Ureteral stricture is a chronic condition that can result in the obstruction of urinary drainage from the affected renal unit, leading to loss of renal function. Treatment methods can be categorized into two main headings: endourological and reconstructive procedures. We aimed to investigate the efficacy and safety of the self-expandable Allium® ureteral stent, which has been used in the minimally invasive treatment of ureteral stenosis in recent years.

MATERIALS AND METHODS

Twenty patients who were applied Allium® ureteral stent between 2017 and 2021 included in the study. The demographic and clinical characteristics of the patients, the details of the treatments applied to the patients, the perioperative and postoperative complications, the treatments applied for the complications and the findings in the follow-up were recorded and evaluated prospectively.

RESULTS

Etiology included urolithiasis in 16 patients (80%), malignancy in 3 patients (15%), and a previous gynecological operation in 1 patient (5%). Stent obstruction was found to be the most common complication in 3 patients (15%). Stent migration was the second most common complication in 2 patients (10%). Our follow-up continues with 15 patients without stent-related complications and stent obstruction. The mean follow-up period was 28 ± 15.7 months.

CONCLUSIONS

Allium ureteral stent is an effective and reliable method in the minimally invasive treatment of ureteral stricture with complications seen at acceptable rates and ease of treatment in the management of complications.

Complete intraureteral stent placement reduces stent-related symptoms: Systemic review and meta-analysis

PURPOSE

The distal coil of a double-J ureteral stent is considered the major cause of stent-related symptoms. We noticed that some recent studies investigated whether complete intraureteral stent placement (CIU-SP) reduced these symptoms. The current systemic review and meta-analysis aimed to evaluate the safety and the effectiveness of CIU-SP, as compared to conventional stent placement (C-SP).

METHODS

We retrieved relevant trials published before December 2021 from three databases, including PubMED, Embase, and Web of Science. The following medical subject heading were used ((complete intraureteral stent) OR (suture stent)) AND (symptom OR pain) AND (randomized OR randomised). The above search was limited to English language publication.

RESULTS

We identified six prospective randomized trials, all of which investigated a short-term (1-2 weeks) stent placement following uncomplicated ureteroscopic lithotripsy. The meta-analysis revealed that CIU-SP significantly reduced stent-related symptoms: CIU-SP had lower USSQ (Ureteral Stent Symptom Questionnaire) Urinary Symptom Index score (MD -5.13; 95%CI [-5.82,-4.44]; P < 0.00001), lower USSQ Pain Index score (MD -4.21; 95%CI [-5.25,-3.17]; P < 0.00001), and lower VAS pain scale (MD -1.93; 95%CI [-2.17,-1.69]; p < 0.00001). Besides, patients with CIU-SP were less likely to have pain (RR 0.78; 95%CI [0.67,0.91]; p = 0.001). There was no significant difference regarding the USSQ General Health and Work Performance. Both CIU-SP and C-SP had similarly few complications of Clavien-Dindo grade ≥2.

CONCLUSION

This meta-analysis reveals that CIU-SP significantly decreases stent-related urinary symptoms and pain. Based on the current evidence, CIU-SP is ready to be applied in clinical practice, at least in those requiring short-term stent placement following uncomplicated ureteroscopic lithotripsy.

Impact of Ureteral Stent Material on Stent-related Symptoms: A Systematic Review of the Literature

Context

Ureteral stents are essential implants that are used on a daily basis. Since their invention, advances in stent design have been directed towards alleviating stent-related symptoms. It remains unclear how the material composition of the stent affects stent-related symptoms.

Objective

To review the literature and define the clinical impact of ureteral stent material on stent-related symptoms.

Evidence acquisition

A literature search of the Embase, MEDLINE (PubMed), and Web of Science databases was conducted on December 17, 2021 to collect articles comparing stent composition materials regarding stent-related symptoms. Thirteen publications met the inclusion criteria, of which only one met the high-quality requirements of the Cochrane Collaboration tool for assessing the risk of bias in randomized trials.

Evidence synthesis

Most trials, including the highest quality trial, seem to support that silicone double-J (DJ) stents reduce stent-related symptoms compared to nonsilicone DJ stents. Regarding physical properties, it seems that “soft” or “flexible” DJ stents reduce stent-related symptoms. However, since there was only one high-quality study with a low risk of bias, it is impossible to draw a definitive conclusion owing to the lack of quality data.

Conclusions

Silicone DJ stents, and by extension “soft” DJ stents, appear to reduce stent-related symptoms compared to nonsilicone polymers and “hard” DJ stents. No definitive conclusion can be drawn owing to a lack of quality evidence. Creating a standard for measuring and reporting physical stent properties should be the first step for further research.

Patient summary

A ureteral stent is a small hollow tube placed inside the ureter to help urine drain from the kidney. We reviewed the literature on the impact of stent material on stent-related symptoms. We found that silicone may reduce stent-related symptoms, but no definitive conclusion can be drawn and further studies are needed.

Distal end of Double-J ureteral stent position on ureteral stent-related symptoms: A systematic review and meta-analysis

Background

Most patients suffer from ureteral stent-related symptoms (USRS) caused by indwelling ureteral stents. Nevertheless, various medications to alleviate discomfort as well as novel stents are continually being developed, and in recent years, some researchers have believed that proper intravesical stent placement can relieve USRS.

Objective

To determine appropriate intravesical ureteral stent position may alleviate USRS.

Methods

Up to May 1, 2022, the PubMed, Embase, Scopus and Web of Science databases were thoroughly searched, and two independent reviewers included relevant studies that met the PICO (Patient, Intervention, Comparison, Outcome) criteria. Studies methodological quality were assessed by ROB2 and ROBINS-I. Ureteral stent symptom questionnaire (USSQ), international prostate symptom score (IPSS) and quality of life (QoL) was used to quantify the USRS. According to intravesical ureteral stent position, Group A was defined as the contralateral group, that is distal end of ureteral stent crossed the bladder midline, whereas Group B was classified as ipsilateral group, meaning stent end did not cross the midline.

Results

Six studies incorporating a total of 590 patients were eligible. In terms of USSQ score, the meta-analysis showed that contralateral group was associated with a significant increase in USSQ total (MD, 17.55; 95% CI, 12.04 to 23.07; P < 0.001), urinary symptoms (MD, 2.74; 95% CI, 0.48 to 5.01; P = 0.02), general health (MD, 4.04; 95% CI, 2.66 to 5.42; P < 0.001), work performance (MD, 1.36; 95% CI, 0.75 to 1.98; P < 0.001) and additional problems (MD, 0.89; 95% CI, 0.47 to 1.32; P < 0.001) scores while not associated with a significant increase in body pain (MD, 3.13; 95% CI, −0.19 to 6.44; P = 0.06) and sexual matters (MD, 1.01; 95% CI, −0.03 to 2.06; P = 0.06). As for IPSS, although no significant differences in IPSS total (MD, 2.65; 95% CI, −0.24 to 5.54; P = 0.07) or voiding symptoms (MD, −0.84; 95% CI, −3.16 to 1.48; P = 0.48) scores were found, ipsilateral group was associated with a significant decrease in storage symptoms (MD, 1.92; 95% CI, 0.91 to 2.93; P = 0.0002). Furthermore, ipsilateral group was linked to a significant decrease in QoL score (MD, 1.00; 95% CI, 0.18 to 1.82; P = 0.02).

Conclusion

This meta-analysis proven that correct intravesical stent position was critical, and patients with stents crossing the midline experienced more severe USRS than those who did not. Further high-quality randomized controlled trials are needed to corroborate our findings.

Advances in ureteral stent technology

PURPOSE OF REVIEW

Ureteral stents are an invaluable tool for urologists but suffer from several drawbacks, including: limited durability due to stent encrustation, significant morbidity from bothersome urinary symptoms, pain and infection, risk of the forgotten stent and costly removal. This review highlights key advances in ureteral stent technology that seek to address these issues.

RECENT FINDINGS

Over the past 2 years clinical trials have brought ureteral stent technology aimed to reduce stent-associated morbidity closer to clinical application. Stent material and changes to stent design show promise in improving patient tolerability without increasing complications. Low-tech innovations such as magnetic and catheter snare removal may quickly reduce costs. Radical advances such as biodegradable stent materials remain in preclinical models but show promise for eliminating the need for stent removal.

SUMMARY

The ideal ureteral stent does not currently exist in clinical practice. This review highlights key studies that have advanced ureteral stent technology in the past 2 years.

The intraureteral placement of the stent's distal end decreases stent-related urinary symptoms: a prospective randomized clinical trial

PURPOSE

We compared intraureteral stent placement (CIU-SP) with conventional stent placement (C-SP) regarding the stent-related symptoms.

METHODS

We randomized patients who underwent ureteroscopic lithotripsy into two groups. In CIU-SP group, a 16-cm or 18-cm stent was placed with its distal end above the ureterovesical junction. In C-SP group, a 22-cm or 24-cm stent was placed in a conventional method. Stent-related symptoms were assessed with the Ureteral Stent Symptom Questionnaire (USSQ) before the stent was removed, around 7 days after the operation. The primary outcome was the urinary symptoms; the secondary outcomes included postoperative pain and quality of life.

RESULTS

We randomized 103 patients, of which 91 (45 in CIU-SP and 46 in C-SP) entered the final analysis. Regarding the primary endpoint, the CIU group had less urinary symptoms; the mean USSQ urinary symptom score was significantly lower in the CIU-SP versus C-SP group (25.5 ± 6.3 vs 31.7 ± 5.9, P < 0.001). The CIU-SP group also had more favorable profiles in the following outcomes: lower USSQ body pain score (15.5 ± 5.3 vs 20.1 ± 5.2, P < 0.001), lower overall pain score (3.2 ± 2.2 vs 5.7 ± 2.3, P < 0.001), less number of pain site (1.0 ± 0.9 vs 1.7 ± 0.9, P = 0.001, lower USSQ general health score (10.4 ± 3.7 versus 13.9 ± 3.4, P < 0.001), and lower USSQ work performance score (5.2 ± 3.3 versus 6.7 ± 2.8, P = 0.033). In either group, there was no complication of Clavien-Dindo Class 2 or greater.

CONCLUSION

The complete intraureteral placement significantly decreases stent-related urinary symptoms and pain. It is also associated with better postoperative general health condition and is less likely to limit physical activity and work ability.

Silicone vs. Polyurethane Stent: The Final Countdown

Ureteric stents are conventionally used in daily urological practice. There is ongoing debate on the superiority of different stent materials, particularly in terms of patient tolerance. We conducted a literature review to compare silicone stents and stents made of other materials from a patient tolerability perspective. We conclude that silicone stents are better tolerated but further research is required.

Developments in Ureteral Stent Technology

Ureteral stents have been utilized for decades in maintaining ureteral patency, most commonly after ureteroscopy in the treatment of urolithiasis. Since their initial development, ureteral stents have had many technological advances that have allowed for better patient outcomes with improvements in comfort, durability, patency, encrustation resistance, biocompatibility, ease of insertion, migration, and biofilm development. Several new ureteral stents enter the market every year, each with their own touted benefits. It is essential to understand the different advantages for each ureteral stent to provide the best available care to patients when possible. The purpose of this review is to give a brief history of ureteral stent development and summarize the recent developments in ureteral stent designs. We aim to review the data supporting the clinical advantages of the latest ureteral stents available for use by urologists.

10-Year Experience with Reinforced Ureteral Stents for Malignant Ureteral Obstruction

Introduction

Malignant ureteral obstruction (MUO) hinders the management of malignant diseases. Indwelling stent is a common method to release renal obstruction, but stent failure with obstruction is frequent. The studies conclude that stent obstruction divides survival by 2 or even 4. We carried out the present study in order to evaluate drainage efficiency and overall survival by using stents with distinctive degrees of stiffness.

Materials and Methods

We performed an analysis of 156 patients with MUO drainage at a single institution from June 2009 to June 2019.

Results

Of the 156 patients, 128 (82.1%) died with a mean survival time of 15.3 ± 14.4 months after the first ureteral stent procedure (USP). In order to study stent failure and overall survival, the patients were divided into 3 groups. Group 1 with patients died soon after only one USP (n=37). Group 2 with patients had more than one USP and no obstruction (n=41). Patients in Group 3 had more than one USP and at least one stent obstruction (n=62). During the study period, 556 USPs were analysed separately. The stent failure with obstruction occurred in 23.0% (128/556) of USP at a mean of 4.4 ± 3.6 months. In case of stent failure, a progressive choice of stents was shaped to overcome each failure by focusing on the criterion of increasingly stiff stents. Patients in Group 1 died soon at mean of 4.9 ± 4.8 months. The mean survival time of patients in Groups 2 and 3 were, respectively, 19.4 ± 11.2 and 21.5 ± 16.3 months (P = 0.19).

Conclusion

MUO is a serious disease but this study is the first to prevent survival rate from falling by choosing the stent stiffness suitable for the patient. The active detection of stent failure has been shown to be essential for preserving survival.