The role of intra-vascular imaging in patients undergoing intravascular lithotripsy: Insights from the COIL registry.

BACKGROUND: The role of intra-coronary imaging in patients with stent failure undergoing intravascular lithotripsy (IVL) is unclear. We aimed to assess clinical outcomes in patients undergoing IVL treatment for stent failure stratified according to the use of intra-coronary imaging and lesion complexity. METHODS: This is a pre-specified subgroup analysis of patients who were included in the coronary intravascular lithotripsy in patients with stent failure (COIL) registry (international multi-centre study assessing IVL treatment for stent failure in 6 European centres). A complex lesion was defined if IVL treatment was used in the left main, true bifurcation, long lesion, or coupled with athero-ablative therapy. The primary endpoint was the composite of cardiac death, spontaneous myocardial infarction, or target vessel revascularization (TVR) at 12 months. RESULTS: There were 102 patients analyzed, of whom 27 (26%) patients had complex anatomy. The use of intra-coronary imaging following IVL in stent failure was more frequent in patients with complex versus Noncomplex anatomy (56% vs. 31%, p = 0.022). IVL treatment was effective in both groups, however, patients with complex anatomy had worse clinical outcomes (30% vs. 11%, p = 0.02), driven by a higher rate of TVR (26% vs. 8%, p = 0.017). In the complex group, patients who underwent intracoronary imaging post intervention had lower event rate compared to those without imaging (13% vs. 50%, p = 0.038). CONCLUSIONS: In patients undergoing IVL treatment for stent failure with complex coronary anatomy, the use of intra-coronary imaging was associated with fewer adverse events compared to angiography guided intervention.

Preoperative parent education and postoperative nurse-led care for boys versus routine hospital care for urethroplasty for hypospadias in Western China: a retrospective study.

Background/aim: Urethroplasty is the preferred treatment for hypospadias but is affected by the severity of anomalies, making it a complex procedure with potential postoperative complications. Following surgery, parents receive instructions and recommendations, whether from nurses or physicians, regardless of complication rates. However, nurses play a crucial role in educating caregivers before surgery and providing postoperative care during follow-up. The study aims to assess parents' knowledge and practices, as well as the frequency of complications in boys who underwent urethroplasty for hypospadias and received postoperative nurse-led care and whose parents received preoperative education against those of boys who underwent urethroplasty under routine hospital care. Materials and methods: In this retrospective study, Han Chinese boys aged 21-41 months in Western China who underwent urethroplasty for hypospadias were divided into two groups: the NI cohort (n = 103), where they received postoperative nurse-led care and their parents received preoperative education, and the RH cohort (n = 142), where boys underwent routine hospital care. Results: After urethroplasty, higher numbers of caregivers with satisfactory knowledge (96 (93%) vs. 80 (56%), p < 0.0001) and practice (102 (99%) vs. 132 (93%), p = 0.0276) were reported in the NI cohort compared to the RH cohort. Additionally, a higher number of boys in the RH cohort experienced adverse effects such as moderate bleeding (13 (9%) vs. 1 (1%), p = 0.0052), wound infection (17 (12%) vs. 4 (4%), p = 0.0356), urinary obstruction (35 (25%) vs. 10 (10%), p = 0.0049), burning sensation (47 (33%) vs. 15 (15%), p = 0.0019), and urinary stent fall (32 (23%) vs. 6 (6%), p = 0.0008) compared to those in the NI cohort. Conclusion: Preoperative instructions enhance caregivers' knowledge and practices following urethroplasty, while postoperative nurse-led care reduces immediate postoperative complications associated with hypospadias in boys.

Pancreaticoduodenal Artery Aneurysm Complicated by Median Arcuate Ligament Syndrome.

PURPOSE: To highlight median arcuate ligament syndrome as a potential cause for celiac artery stenosis and pancreaticoduodenal artery aneurysm, and describe treatment options in this setting. CASE REPORT: A 63-year-old male presented with a pancreaticoduodenal artery aneurysm and concomitant celiac artery stenosis that was treated with celiac artery stenting and aneurysm coiling. He subsequently developed stent fracture and celiac artery occlusion secondary to previously unrecognized median arcuate ligament syndrome causing reperfusion of the aneurysm. This was treated with open median arcuate ligament release and aorta to common hepatic artery bypass with good clinical result and stable 20-month surveillance imaging. CONCLUSION: It is critical to recognize median arcuate ligament syndrome as a cause of celiac artery stenosis in the setting of pancreaticoduodenal artery aneurysm given the high risk of failure of endovascular stenting. Open aorto-hepatic artery bypass and endovascular aneurysm coiling should be the preferred approach in these patients.

Stenting of high-tortuous ducts in duct-dependent pulmonary circulation: essential points to consider before deciding on stenting.

Despite the advancements in the technique of duct stenting (DS) in patients with duct-dependent pulmonary circulation (DDPC) and the valuable role of DS in preventing the risk of surgical creation of shunts and early repair, not all ducts are amenable to being stented, and not all interventions with DS are safe and can achieve positive outcomes. Very few studies focusing on tortuous ducts have been conducted until now. Their results showed that stenting of highly tortuous ducts has the same risk as surgical options. This type of stenting has greater possibility of complications, early in-stent thrombosis, and stent failure than do other duct types. In such cases, the surgical options could be superior to DS and have better outcomes. This report aims to review the very scarce available data about stenting of high-tortuous ducts and criticisms of performing DS in ducts associated with pulmonary stenosis and to highlight the essential points that must be considered before deciding on intervention.

Long-term clinical outcomes of excimer laser coronary atherectomy for the management of recurrent in-stent restenosis.

BACKGROUND: Recurrent in-stent restenosis (ISR) remains a serious problem. Optimal modification of the underlying mechanism during index percutaneous coronary intervention (PCI) is key to prevent ISR. Excimer laser coronary atherectomy (ELCA) has its own indications and is among others used in recurrent ISR in case of stent underexpansion and/or diffuse neointimal hyperplasia. We aimed to assess the long-term clinical outcomes of ELCA for the management of recurrent ISR. METHODS: A multicenter, retrospective observational study was conducted. Patients with recurrent ISR who were additionally treated with ELCA were included. The primary outcome was major adverse cardiac events (MACE) defined as a composite of cardiovascular death, myocardial infarction, stroke, target lesion revascularization at 12 months, and longer term. RESULTS: Between 2014 and 2022, 51 patients underwent PCI with the additional use ELCA for recurrent ISR. Primary outcome occurred in 6 patients (11.8%) at 12 months and in 12 patients (23.5%) at a median follow-up of 4 (1-6) years. Technical and procedural success were achieved in 92% and 90% of cases, respectively. Coronary perforation occurred in 2 patients as a result of distal wire perforation, but was not ELCA-related. There were no in-hospital MACE. CONCLUSIONS: ELCA appears to be a safe method with acceptable long-term results for the management of recurrent ISR.

Clinical outcomes of coronary intravascular lithotripsy in patients with stent failure (COIL registry).

BACKGROUND: Intravascular lithotripsy (IVL) has been demonstrated to be an effective treatment of calcified de novo coronary lesions. Safety data on the use of IVL within stented segments are lacking. We sought to evaluate the safety, feasibility, and long-term outcomes of IVL in patients with stent failure. METHODS: This was a retrospective multi-centre registry that included consecutive patients with stent failure who had undergone IVL treatment. The primary efficacy endpoint was procedural success defined as residual stenosis <30% (determined by quantitative coronary angiography analysis) in patients who survived hospital admission without in-hospital adverse events. Major adverse cardiovascular events (MACE) were defined as the composite endpoints of cardiovascular death, spontaneous myocardial infarction, and target vessel revascularisation at one-year follow up. RESULTS: 102 patients were included in this study. Mean age was 73 ± 9 years and 81% were male. The duration from previous stent implantation and IVL treatment was 24 (interquartile range 7-76) months, of which 10.8% received IVL for acute under-expanded stent. IVL treatment allowed significant improvement in both minimal lumen diameter (1.14 ± 0.60 to 2.53 ± 0.59, P < 0.001) and degree of stenosis (66.8 ± 19.9 to 20.3 ± 11.3%, P < 0.001). The rate of procedural success was 78.4% (80/102 of patients). The one-year MACE was 15.7%. Ostial disease (HR 5.16; 95% CI 1.19 to 22.33; P = 0.028) and lesion length (HR 1.05; 95% CI 1.01 to 1.10; P = 0.010) were independently associated with one-year MACE. CONCLUSIONS: In patients with stent failure, IVL is a safe and feasible treatment for this high-risk group.

Myocardial revascularization failure among patients requiring cardiac catheterization and secondary revascularization in contemporary clinical practice: Results of the REVASEC multicenter registry.

BACKGROUND: Myocardial revascularization failure (MRF) and Secondary revascularization (SR) are contemporary interventional cardiology challenges. AIM: To investigate the characteristics, management, and prognosis of patients with myocardial revascularization failure (MRF) and need for secondary revascularization (SR) in contemporary practice. METHODS: The REVASEC study is a prospective registry (NCT03349385), which recruited patients with prior revascularization referred for coronary angiography at 19 centers. The primary endpoint is a patient-oriented composite (POCE) at 1 year, including death, myocardial infarction, or repeat revascularization. RESULTS: A total of 869 patients previously revascularized by percutaneous intervention (83%) or surgery (17%) were recruited. MRF was found in 83.7% (41.1% stent/graft failure, 32.1% progression of coronary disease, and 10.5% residual disease). SR was performed in 70.1%, preferably by percutaneous intervention (95%). The POCE rate at 1 year was 14% in the overall cohort, with 6.4% all-cause death. In the multivariate analysis, lower POCE rates were found in the groups without MRF (9.4%) and with disease progression (11%) compared with graft/stent failure (17%) and residual disease (18%), hazard ratio 0.67 (95% confidence interval: 0.45-0.99), p = 0.043. At 1 year, the SR group had less chronic persistent angina (19% vs. 34%, p < 0.001), but a higher rate of repeat revascularization (9% vs. 2.9%, p < 0.001). CONCLUSION: MRF was found in 84% of patients with prior revascularization referred for coronary angiography. Stent/graft failure and residual coronary disease were associated with a worse prognosis. SR provided better symptom control at the expense of a higher rate of new revascularization.

Poor Below Knee Runoff Impacts Femoropopliteal Stent Failure and Fluoropolymer Antithrombotic Effect in Healthy Swine Model.

OBJECTIVE: Poor below knee (BTK) runoff is a predictor of stent failure after endovascular femoropopliteal artery treatment; however, lack of pathological evaluation has prevented characterisation of stent failure. The study aimed to investigate the impact of poor BTK runoff and the antithrombotic effect of the polymer of fluoropolymer coated paclitaxel eluting stents (FP-PESs) in a healthy swine femoropopliteal artery model. METHODS: FP-PESs and bare metal stents (BMSs) and FP-PES and polymer free paclitaxel coated stents (PF-PCSs) were implanted in the bilateral femoral arteries of healthy swine (n = 6, respectively) following coil embolisation in both tibial arteries to induce poor BTK runoff. Histological assessment and intravascular imaging device evaluation were performed at one month. The Japanese Association for Laboratory Animal Science approved the study protocol (reference number: IVT22-90). RESULTS: Optical coherence tomography showed significantly lower percent area stenosis in FP-PES compared with BMS (37.3%, [interquartile range (IQR), 25.6 - 54.3] % vs. 92.5% [IQR, 75.5 - 96.1] %, respectively, p = .031), and PF-PCS (8.3% [IQR, 4.5 - 27.0] % vs. 31.2% [IQR, 23.3 - 52.2] %, respectively, p = .031). Histopathological evaluation demonstrated that thin fibrin attachment without re-stenosis was the most dominant neointimal tissue characteristic in FP-PES. On the other hand, neointimal tissue characteristics with significant restenosis of BMS and PF-PCS were mainly organising or organised thrombus. CONCLUSION: Organising and or organised thrombus attachment due to poor BTK runoff was the main cause of in stent restenosis of the swine femoral artery. FP-PES demonstrated the least percent area stenosis, suggesting the importance of the antithrombotic effect of polymer.

It is Possible to Reduce Ureteral Stent Clogging and Stent-Related Symptoms to Soothe the Pain of the Patient: A Case Report.

Introduction: Ureteral stent obstruction hinders the management of malignant diseases. Adequate stent insertion through an obstructed ureter does not necessarily guarantee renal decompression and stent-related symptoms adversely affect patient comfort. There are two major problems associated with ureteral stents: obstruction and intolerance to the stents. Case Presentation: A 45-year-old woman was treated for cervical cancer with metastatic lymph nodes and ureteral obstruction with chemotherapy, radiotherapy, immunotherapy, and bilateral retrograde stenting. After recurrent stent obstruction, stent replacement was attempted more than 18 times over two years. In addition, stent-related symptoms adversely affected patient comfort. The patient was finally fitted with Superglide 8-French reinforced ureteral stents. Their replacement every six months was viewed by the patient as a relief compared to the all too frequent replacement of the previous stents. Moreover, the customized changes in the shape of Superglide stents improved patient comfort. Discussion: Recent publications tend to indicate that large-lumen ureteral stents are most likely to remain permeable over time. Various modifications of the bladder or endo-ureteral part of double-pigtail stents have been increasingly reported, with the aim of improving their tolerance while maintaining effective drainage. Conclusion: Adaptation of the internal lumen and shape of stents to the characteristics of the tumor and patient measurements appears to be important for increasing the drainage and tolerance of ureteral stents. The top priority for future ureteral stents suitable for malignant diseases should be to integrate these characteristics based on state-of-the-art data.

Investigating the encrustation of reinforced ureteral stents by computational flow dynamic simulations.

PURPOSE: In cases of extrinsic ureteral obstruction, obstruction due to encrustation is particularly detrimental to functioning of the stent. A thorough understanding of the causes that lead to stent encrustation is essential. Computational fluid dynamic (CFD) simulations may provide a reliable screening platform for investigating the interplay between flow processes and encrustation dynamics in stents. METHODS: Using a tailor-made program, we attempted to evaluate a number of reinforced ureteral stents by CFD simulations with an obstructed or unobstructed ureter and steady or discontinuous flow patterns to identify critical regions with abrupt changes in shape susceptible to stagnant flow and encrustation. RESULTS: For the Vortek® and Urosoft stents, the longitudinal opening of the stents confirmed the presence of critical regions. No critical region was observed for the Superglide stent. CFD simulations showed that cavities formed near the critical regions represented patently stagnant flow and were potentially susceptible to the formation of encrusting deposits. Encrustations were greater in the obstructed design than in the unobstructed design. In the model with a suddenly interrupted laminar flow, the peristaltic motion resulted in new discontinuous encrustation areas scattered throughout the entire external and internal surface of the stent. CONCLUSION: The analysis of fluid dynamics through the tested stents confirmed that encrustations are possible in regions of stagnant flow and showed that stent models with the smoothest possible surface are preferable. The discontinuous flow model provided results that are closer to the findings observed in the clinic and should be more often integrated into CFD simulations.

Management of single double-J stent failure in malignant ureteral obstruction: tandem ureteral stenting with less frequent stent exchange

PURPOSE: To evaluate the safety and efficacy of the placement and exchange of tandem ureteral stents (TUS) under fluoroscopic guidance in the management of indwelling single double-J stent (DJS) failure in patients with malignant ureteral obstruction. We also aimed to investigate whether the generally accepted exchange period of DJSs could be extended using TUS. METHODS: This retrospective study involved 11 patients (10 female) with an age range of 27-64 years, median of 49 years, who underwent TUS (ipsilateral two 8F DJSs) placement due to indwelling single DJS failure occurring in less than 3 months. TUS exchanges were performed initially at 6-month intervals, and subsequent exchange intervals were extended to 9 and 12 months for seven patients. The interval from initial TUS placement to percutaneous nephrostomy, repeat exchange, or death was defined as the duration of stent patency. RESULTS: Indwelling single DJS failure occurred during a median follow-up of 45 days (range, 35-60 days) in 14 ureters of 11 patients. TUS were successfully placed and exchanged with a technical success rate of 100% without any early major complications. Thirty-nine procedures (11 placement and 28 exchange procedures) in 55 ureters were performed. The median duration of urinary patency was significantly higher with TUS [300 days (range, 60-440 days)] compared with single DJSs [45 days (range, 35-60 days)] (P < 0.001). CONCLUSION: The placement and exchange of TUS can be safely and effectively performed under fluoroscopic guidance. The need for frequent DJS exchange could be reduced with increased duration of stent patency using TUS.

Impact of intravascular ultrasound-incomplete stent apposition on stent failure.

OBJECTIVES: This study aimed to investigate the relationship between immediate incomplete stent apposition (ISA) detected by intravascular ultrasound (IVUS) and midterm stent failure. BACKGROUND: Stent failure is one of serious clinical events related to percutaneous coronary intervention (PCI). The previous studies using optical coherence tomography showed that ISA could be associated with stent thrombosis. However, the association between immediate ISA detected by IVUS and stent failure has not been fully investigated. METHODS: We included 396 lesions that underwent elective PCI, and divided those into the appropriate stent apposition (ASA) group (n = 290) and the ISA group (n = 106). The primary endpoint was stent failure, which was defined as a composite of ischemia-driven target lesion revascularization and stent thrombosis. We compared clinical and lesion characteristics between the two groups, and performed a multivariate COX hazard analysis to investigate the association between immediate ISA and stent failure. RESULTS: The median follow-up duration was 1296 days. The Kaplan-Meier curves revealed the higher incidence of stent failure in the ISA group than in the ASA group (p < 0.001). The multivariate stepwise COX hazard analysis showed that immediate ISA (hazard ratio 4.97, 95% confidence interval 1.31-18.82, p = 0.018) was significantly associated with stent failure. When we set the cut-off value of the immediate ISA distance as 0.25 mm, the distance ≥ 0.25 mm had 68.8% sensitivity and 85.0% specificity to predict stent failure. CONCLUSIONS: Immediate ISA detected by IVUS was associated with midterm stent failure. We should pay attention to reduce immediate ISA for improving the midterm outcomes.

Factors Associated with Ureteral Stent Failure in Patients with Malignant Ureteral Obstruction.

Introduction: Management of malignant ureteral obstruction (MUO) with ureteral stents remains a clinical challenge, often involving frequent stent exchanges attributable to stent failure or other urological complications. We report our institutional experience with ureteral stents for management of MUO, including analysis of clinical factors associated with stent failure. Methods: We performed a retrospective review of patients treated with indwelling ureteral stents for MUO in nonurothelial malignancies at our tertiary-care institution between 2008 and 2019. Univariate Cox proportional hazards analysis was performed to identify clinical variables associated with stent failure and stent-related complications. Stent failure was defined as need for unplanned stent exchange, placement of percutaneous nephrostomy (PCN), or tandem stents. Results: In our cohort of 78 patients, the median (range) number of stent exchanges was 2 (0-17) during a total stent dwell time of 4.3 (0.1-40.3) months. Thirty-four patients (43.6%) developed a culture-proven urinary tract infection (UTI) during stent dwell time. Thirty-five patients (44.8%) had stent failure. Twenty-two patients (28.2%) underwent unplanned stent exchanges, 23 (29.5%) required PCN after initial stent placement, and 6 (7.7%) required tandem stents. Ten (28.6%) patients with stent failure were treated with upsized stents, which led to resolution in seven patients. Stent failure occurred with 20/44 (45.4%) Percuflex™, 15/27 (55.6%) polyurethane, and 2/3 (66.7%) metal stents. In patients with ≥2 exchanges (N = 45), median time between exchanges was 4.1 (2.0-14.8) months. Bilateral stenting and history of radiation predicted UTI development. Median overall patient survival after initial stent placement was 19.9 months (95% CI 16.5-37.9 months). Conclusions: Ureteral stent failure poses a significant medical burden to patients with MUO. Better methods to minimize stent-related issues and improve patient quality of life are needed. Using a shared decision-making approach, clinicians and patients should consider PCN or tandem stents early in the management of MUO.

Tumor Stent for Chronic Ureteral Obstruction: Which Are Predictors of Stent Failure?

Purpose: To identify predictors of UROSOFT® tumor stent failure. According to the manufacturer, this reinforced ureteral stent has a maximal dwell time of 6 months. Nonetheless, stent failure may reduce this maximal dwell time. Methods: All patients undergoing first-time UROSOFT tumor stent insertion in our institution between 2010 and 2018 were considered for this retrospective analysis. Primary endpoint was stent failure and defined as premature stent exchange or percutaneous nephrostomy insertion. The local ethics committee approved the study protocol (study ID: BASEC 2020-00175). Results: In total, 182 patients were available for analysis. Median age was 68 years. Causes for tumor stent placement were extrinsic ureteral obstruction in 144 patients (79%) and intrinsic obstruction in 38 patients (21%). Tumor stent failure-free survival estimates at 1, 2, 3, 4, and 5 months were 89%, 83%, 76%, 65%, and 52%, respectively. Patients with stent failure had significantly higher grade of hydronephrosis, higher urinary culture bacterial growth, higher serum white blood cell count, higher C-reactive protein, and lower estimated glomerular filtration rate at the time of reintervention, compared with patients who underwent regular stent exchange. Of all baseline and perioperative parameters, we found bilateral insertion, intrinsic ureteral obstruction, and urinary tract infection (UTI) at time of tumor stent insertion to be significant and independent predictors of stent failure (all p < 0.05). Conclusion: Despite a theoretical maximal dwell time of 6 months, ∼50% of all cases are subject to premature stent failure. Predictors of stent failure are bilateral insertion, intrinsic ureteral obstruction, and UTI at the time of tumor stent insertion. Preoperative antibiotic therapy may impact on stent failure rate.

Impact of Intracoronary Optical Coherence Tomography in Routine Clinical Practice: A Contemporary Cohort Study.

BACKGROUND/PURPOSE: Guidelines recommend intracoronary optical coherence tomography (OCT) to assess stent failure and guide percutaneous coronary intervention (PCI) but OCT may be useful for other indications in routine clinical practice. METHODS/MATERIALS: We conducted an international registry of OCT cases at two large tertiary care centers to assess clinical indications and the potential impact on decision making of OCT in clinical routine. Clinical indications, OCT findings, and their impact on interventional or medical treatment strategy were retrospectively assessed. RESULTS: OCT was performed in 810 coronary angiography cases (1928 OCT-pullbacks). OCT was used for diagnostic purposes in 67% (N = 542) and OCT-guided percutaneous coronary intervention in 50% (N = 404, 136 cases with prior diagnostic indication). Most frequent indications for diagnostic OCT were culprit lesion identification in suspected ACS (29%) and stent failure assessment (28%). OCT findings in the diagnostic setting influenced patient management in 74%. OCT-guided PCIs concerned ACS patients in 45%. Among the 55% with chronic coronary syndrome, long lesions >28 mm (19%), left main PCI (16%), and bifurcation PCI with side-branch-stenting (5%) were the leading indications for PCI-guidance. Post-procedural OCT findings led to corrective measures in 52% (26% malapposition, 14% underexpansion, 6% edge dissection, 3% intrastent mass, 3% geographic plaque miss). CONCLUSIONS: OCT was most frequently performed to identify culprit lesions in suspected ACS, for stent failure assessment, and PCI-guidance. OCT may impact subsequent treatment strategies in two out of three patients.

Analysis of Ureteral Tumour Stents for Malignant Ureteral Obstruction: Towards Reshaping an Optimal Stent.

INTRODUCTION: Ureteral obstruction hinders the management of malignant diseases. Adequate stent placement does not necessarily guarantee renal decompression. The stent stiffness may play a major role to maintain patency. We carried out the present study in order to evaluate drainage efficiency by using stents with distinctive degrees of stiffness and to identify the physical factors that could prevent obstruction of the stent in patients with malignant ureteral obstruction (MUO). MATERIALS AND METHODS: We performed an analysis of 150 patients with MUO drainage at a single institution from June 2009 to June 2019. A progressive choice of stents was shaped to overcome each failure by focusing on the criterion of increasingly stiff stents. RESULTS: During the study period, 556 ureteral stent procedures (USP) 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 and depended on the type of stent. Stent failure occurred in 34.2% (70/205) of Vortek® stents, in 42.9% (15/35) of Urosoft stents, in 15.4% (39/254) of Superglide or ureteral catheters and in 6.5% (4/62) of tandem stents. No significant differences were found between Vortek® and Urosoft stents regarding stent failures, but there were significant differences between Superglide or Tandem stents and Vortek® or Urosoft stents (p<10-7). The study demonstrated that ureteral stent obstruction significantly decreased with a larger lumen or a stiffer stent (p<10-7). CONCLUSION: In the present study, Superglide and tandem stents were the best stents against stent failure, and the lumen and the stiffness of the stent have been shown to be critical factors in controlling patency. The results suggest that the lumen seems more important than the stiffness, and the stiffness would be the only means of keeping the lumen intact. Future stents for MUO should integrate the importance of the lumen of the stent.

Factors Influencing Stent Failure in Chronic Total Occlusion Coronary Intervention.

Stent failure remains one of the greatest challenges for interventional cardiologists. Despite the evolution to superior second- and third-generation drug-eluting stent designs, increasing use of intracoronary imaging and the adoption of more potent antiplatelet regimens, registries continue to demonstrate a prevalence of stent failure or target lesion revascularisation of 15-20%. Predisposition to stent failure is consistent across both chronic total occlusion (CTO) and non-CTO populations and includes patient-, lesion- and procedure-related factors. However, histological and pathophysiological properties specific to CTOs, alongside complex strategies to treat these lesions, may potentially render percutaneous coronary interventions in this cohort more vulnerable to failure. Prevention requires recognition and mitigation of the precipitants of stent failure, optimisation of interventional techniques, including image-guided precision percutaneous coronary intervention, and aggressive modification of a patient's cardiovascular risk factors. Management of stent failure in the CTO population is technically challenging and itself begets recurrence. We aim to provide a comprehensive review of factors influencing stent failure in the CTO population and strategies to attenuate these.