Clinical Value of the Quantitative Flow Ratio to Predict Long-term Target Vessel Failure in Patients with In-stent Restenosis after Drug-coated Balloon Angioplasty

Objective The study sought to investigate the clinical predictive value of quantitative flow ratio(QFR)for the long-term target vessel failure(TVF)outcome in patients with in-stent restenosis(ISR)by using drug-coated balloon(DCB)treatment after a long-term follow-up.Methods This was a retrospective study.A total of 186 patients who underwent DCB angioplasty for ISR in two hospitals from March 2014 to September 2019 were enrolled.The QFR of the entire target vessel was measured offline.The primary endpoint was TVF,including target vessel-cardiac death(TV-CD),target vessel-myocardial infarction(TV-MI),and clinically driven-target vessel revascularization(CD-TVR).Results The follow-up time was 3.09±1.53 years,and 50 patients had TVF.The QFR immediately after percutaneous coronary intervention(PCI)was significantly lower in the TVF group than in the no-TVF group.Multivariable Cox regression analysis indicated that the QFR immediately after PCI was an excellent predictor for TVF after the long-term follow-up[hazard ratio(HR):5.15×10−5(6.13×10−8−0.043);P<0.01].Receiver-operating characteristic(ROC)curve analysis demonstrated that the optimal cut-off value of the QFR immediately after PCI for predicting the long-term TVF was 0.925(area under the curve:0.886,95%confidence interval:0.834–0.938;sensitivity:83.40%,specificity:88.00;P<0.01).In addition,QFR≤0.925 post-PCI was strongly correlated with the TVF,including TV-MI and CD-TVR(P<0.01).Conclusion The QFR immediately after PCI showed a high predictive value of TVF after a long-term follow-up in ISR patients who underwent DCB angioplasty.A lower QFR immediately after PCI was associated with a worse TVF outcome.

Treatment of coronary in-stent restenosis： a systematic review

Coronary stem implantation has significantly improved percutaneous coronary intervention and enabled the management of early complications of plain balloon angioplasty. However, a new complication has accompanied these improvements： in-stent restenosis （ISR） arising from neointimal hyperplasia. ISR after coronary angioplasty is currently one of the main limitations of this method, leading to the recurrence of exertional angina pectoris or acute coronary syndromes. The clinical incidence of ISR after bare-metal stent （BMS） implantation is approximately 20%35%. The use of drug-eluting stents （DES） has led to a further decrease in the occurrence of ISR to 5%-10%. Evidence resulting from controlled clinical studies suggests that DES and drug-eluting balloon catheters （DEB） provide the best clinical and angiographic results in the treatment of ISR. We undertook a systematic review of the pathophysiology, diagnostics and treatment options for BMS- and DES-ISR. We discuss recent randomised studies, comparing different DES or DEB used for BMS or DES-ISR treatment, as well as the use of new biovascular scafolds and the topic of scafold restenosis.

New predictors of in-stent restenosis in patients with diabetes mellitus undergoing percutaneous coronary intervention with drug-eluting stent

Background Percutaneous coronary intervention （PCI） had become the major therapeutic procedure for coronary artery disease （CAD）, but the high rate of in-stent restenosis （ISR） still remained an unsolved clinical problem in clinical practice. Increasing evidences suggested that diabetes mellitus （DM） was a major risk factor for ISR, but the risk predictors of ISR in CAD patients with DM had not been well characterized. The aim of this study was to investigate the clinical and angiographic characteristic predictors significantly associated with the occurrence of ISR in diabetic patients following coronary stenting with drug-eluting stent （DES）. Methods A total of 920 patients with diabetes who diagnosed CAD and underwent coronary DES implantation at Beijing Anzhen Hospital in China were consecutively enrolled from January 2012 to December 2012. Of these, 440 patients underwent the second angiography within ≥ 6 months due to the progression of treated target lesions. Finally, 368 of these patients who met the inclusion and exclusion criteria were followed up by angiography after baseline PCI. According to whether ISR was detected at follow-up angiography, patients were divided into the ISR group （n = 74） and the non-ISR group （n = 294）. The independent predictors of ISR in patients with DM were explored by multivariate Cox＇s proportional hazards regression models. Results A total of 368 patients （260 women and 108 men） with a mean ages of 58.71 ± 10.25 years were finally enrolled in this study. Of these, ISR occurred in 74/368 diabetic patients （20.11%） by follow-up angiography. Univariate analysis showed that most baseline characteristics of the ISR and non-ISR group were similar. Patients in the ISR group had significantly higher serum very low density lipoprotein cholesterol （VLDL-C）, triglyceride （TG） and uric acid （UA） levels, more numbers of target vessel lesions, higher prevalence of multi-vessel disease, higher SYNTAX score, higher rate of previous but lower rate of drinking compared with patients in the non-ISR group. The independent predictors of ISR in patients with DM after DES implantation included VLDL-C （HR = 1.85, 95% CI： 1.24-2.77, P = 0.002）, UA （per 50 μmol/L increments, HR = 1.19, 95% CI： 1.05 1.34, P = 0.006）, SYNTAX score （per 5 increments, HR = 1.34, 95% CI： 1.03-1.74, P = 0.031） and the history ofPCI （HR = 3.43, 95% CI： 1.57-7.80, P = 0.003） by the multivariate Cox＇s proportional hazards regression analysis. Conclusions The increased serum VLDL-C and UA level, higher SYNTAX score and the history of previous PCI were independent predictors of ISR in patients with DM after coronary DES implantation. It provided new evidence for physi- cians to take measures to lower the risk oflSR for the better management of diabetic patients after PCI.

Recent advances in cardiovascular stent for treatment of in-stent restenosis:Mechanisms and strategies

Treatments of atherogenesis,one of the most common cardiovascular diseases(CVD),are continuously being made thanks to innovation and an increasingly in-depth knowledge of percutaneous transluminal coronary angioplasty(PTCA),the most revolutionary medical procedure used for vascular restoration.Combined with an expanding balloon,vascular stents used at stricture sites enable the long-time restoration of vascular permeability.However,complication after stenting,in-stent restenosis(ISR),hinders the advancement of vascular stents and are associated with high medical costs for patients for decades years.Thus,the development of a high biocompatibility stent with improved safety and efficiency is urgently needed.This review provides an overview of current advances and potential technologies for the modification of stents for better treatment and prevention of ISR.In particular,the mechanisms of in-stent restenosis are investigated and summarized with the aim to comprehensively understanding the pathogenesis of stent complications.Then,according to different therapeutic functions,the current stent modification strategies are reviewed,including polymeric drug eluting stents,biological friendly stents,prohealing stents,and gene stents.Finally,the review provides an outlook of the challenges in the design of stents with optimal properties.Therefore,this review is a valuable and practical guideline for the development of cardiovascular stents.

Comparison of the efficacy of drug-eluting balloon for de novo lesions and in-stent restenosis lesions of the femoropopliteal arteries

Objective:To compare the efficacy of drug-eluting balloons for de novo and in-stent restenosis(ISR)for lesions of the femoropopliteal arteries during 12-month follow-up.Materials and methods:A retrospective analysis of 66 patients was performed.These patients had lower extremity atherosclerosis obliterans and were treated with drug-eluting balloons from June 2016 to June 2017.All the lesions were femoropopliteal,including 47 de novo lesions and 19 ISR lesions.Clinical results were followed up at 6 months and 12 months postoperatively.The primary patency rate,target lesion revascularization,Rutherford classification,ankle-brachial index,amputation rate and mortality were compared between the two groups.Results:All the 66 patients underwent the treatment of femoropopliteal artery lesions with unilateral limbs.The surgical success rates were 100%.No adverse events such as acute ischemia or amputation occurred in the hospital.There was no difference between the two groups'Rutherford classification and the ankle-brachial index at the 6-month follow-up(p>0.05).At the 12-month follow-up,the de novo group's Rutherford classification was lower than the ISR group(p=0.026),and the ankle-brachial index of the ISR group was lower(0.66±0.033 vs 0.52±0.056,p=0.036).There was no difference between the patency rate of the de novo group and the ISR group(93.6%vs 84.2%,p=0.229)at the 6-month follow-up.However,the ISR group patency rate was lower at the 12-month follow-up(63.2%vs 85.1%,p=0.048).As for revascularization there was no significant difference between the two groups at the 6-month follow-up(4.2%vs 10.5%,p=0.334),but a higher rate occurred in the ISR group at the 12-month follow-up(26.3%vs 6.4%,p=0.025).There were no significant differences in the mortality or amputation rate between the two groups(p>0.05).Conclusions:Drug-eluting balloons were effective in treating both de novo lesions and ISR lesions in the atherosclerotic femoropopliteal artery,but the 12-month follow-up results of ISR lesions were less favorable than the de novo lesions.

COMPARISON OF SHORT- AND LONG-TERM OUTCOMES BETWEEN CYPHER AND TAXUS DRUG-ELUTING STENTS FOR IN-STENT RESTENOSIS

Objective To compare the short- and long-term clinical outcomes between sirolimus-eluting stent （ Cypher stent） and paclitaxel-eluting stent （TAXUS stent） in patients with in-stent restenosis （ISR） lesions of the coronary arteries. Methods From December 2002 to March 2005, 253 patients with ISR lesions of the coronary arteries were selected and divided into two groups. Cypher group （152 cases） was treated with Cypher or Cypher Select stents, and TAXUS group （101 cases） with TAXUS stents. A total of 262 ISR lesions in these patients were treated with 308 drog-eluring stents （DESs）, including 176 Cypher or Cypher Select stents and 132 TAXUS stents. All patients were followed up for 10 months. Procedure success rates of DES implantation in both groups were observed. Major adverse cardiac events （MACE） rates in hospital and at 10 months follow-up, as well as in-DES restenosis observed using coronary angiography at follow-up were compared between two groups. Results Success rate of DES implantation was 100% in both groups. No significant difference in MACE rate during hospitalization was found between the two groups. However, at 10 months follow-up, MACE rate was higher in TAXUS group than in Cypher group （ 16.00% vs. 6.67%, P =0. 031 ）. As for coronary angiography at 10 months follow-up, we observed an increasing tendency of in-DES restenosis rate in TAXUS group compared with Cypher group （29.41% vs. 14.04%, P=0.075）. Conclusions Cypher and TAXUS DESs both have good short- and long-term outcomes in treating ISR. Cypher DES proved better long-term clinical outcome than TAXUS DES.

Comparison of the safety and efficacy of two types of drug-eluting balloons （RESTORE DEB and SeQuent Please） in the treatment of coronary in-stent restenosis： study protocol for a randomized controlled trial （RESTORE ISR China）

1 Introduction In-stent restenosis （ISR）, characterized by neointimal proliferation and/or neoatherosclerosis in the vessel of the stent, can cause a reduction in lumen diameter after stent implantation, which can directly induce the recurrence of angina symptoms or an acute coronary syndrome in patients and is usually life-threatening.

Intracoronary brachytherapy for the treatment of recurrent drugeluting stent in-stent restenosis:A systematic review and metaanalysis

BACKGROUND We performed a meta-analysis on observational studies since randomized control trials are not available.We studied intracoronary brachytherapy(ICBT)and recurrent drug eluting stent in-stent restenosis(DES-ISR)to evaluate the procedural success,target lesion revascularization(TLR),incidence of myocardial infarction(MI)and all-cause mortality at 2 years follow-up.AIM To perform meta-analysis for patients undergoing ICBT for recurrent DES-ISR.METHODS We performed a systematic search of the PubMed/MEDLINE,Cochrane and DARE databases to identify relevant articles.Studies were excluded if intracoronary brachytherapy was used as a treatment modality for initial ISR and studies with bare metal stents.We used a random-effect model with DerSimonian&Laird method to calculate summary estimates.Heterogeneity was assessed using I2 statistics.RESULTS A total of 6 observational studies were included in the final analysis.Procedural angiographic success following intra-coronary brachytherapy was 99.8%.Incidence of MI at 1-year was 2%and 4.1%at 2-years,respectively.The incidence of TLR 14.1%at 1-year and 22.7%at 2-years,respectively.All-cause mortality at 1-and 2-year follow-up was 3%and 7.5%,respectively.CONCLUSION Given the observational nature of the studies included in the analysis,heterogeneity was significantly higher for outcomes.While there are no randomized controlled trials or definitive guidelines available for recurrent ISR associated with DES,this analysis suggests that brachytherapy might be the alternative approach for recurrent DES-ISR.Randomized controlled trials are required to confirm results from this study.

Finite Element Simulation of In-Stent Restenosis with Tissue Growth Model

In this study, a finite element simulation of in-stent restenosis (ISR) is conducted to simulate the deployment and expansion of a stent in an occluded artery with a contact model and a mechanics-based growth model. A tissue growth model based on the multiplicative decomposition of deformation is applied to investigate the growth of the plaque and artery wall upon the stent’s implantation. Due to the high stresses at the contact points between the stent struts and the tissue, further tissue injury or restenosis is observed. The simulation results show that after the stent deployment, the von Mises stress is significantly larger in the plaque compared to the artery wall, especially in the region that is in contact with the stent. However, the growth of the plaque and artery tends to even out the stress concentration over time. The tissue growth is found to be more significant near the inner wall than the outer layer. A 0.77 mm restenosis is predicted, which agrees with published clinical observations. The features of the artery growth are carefully analyzed, and the underlying mechanism is discussed. This study is the first attempt to apply finite element analysis to artery restenosis, which establishes a framework for predicting ISR’s occurrence and severity. The results also provide insights into understanding the underlying mechanism of in-stent restenosis.

Diagnosis and management challenges of in-stent restenosis in coronary arteries

Over the course of the 3 decades, percutaneous coronary intervention(PCI) with stent implantation transformed the practice of cardiology. PCI with stenting is currently the most widely performed procedure for the treatment of symptomatic coronary disease. In large trials, drugeluting stents(DES) have led to a significant reduction in in-stent restenosis(ISR) rates, one of the major limitations of bare-metal stents. Due to these favorable findings, DES was rapidly and widely adopted enabling more complex coronary interventions. Nevertheless, ISR remains a serious concern as late stent complications. ISR mainly results from aggressive neointimal proliferation and neoatherosclerosis. DES-ISR treatment continues to be challenging complications for interventional cardiologists.

Drug-eluting balloons versus new generation drug-eluting stents for the management of in-stent restenosis: an updated meta-analysis of randomized studies

Background New-generation drug-eluting stents (DES) was more effective in the treatment of in-stent restenosis (ISR) compared with the first-generation DES. Drug-eluting balloons (DEB) and new-generation DES had been available strategies in treatment of bare-metal stents/DES ISR (BMS/DES-ISR). Six new randomized trials have recently examined the angiographic outcomes and one-year clinical outcomes of DEB and new generation DES in BMS/DES-ISR. However, the optimal management for BMS/DES-ISR lesions remains controversial. Methods We searched the randomized clinical trials evaluating the angiographic outcomes and one-year clinical outcomes of DEB and new-generation DES in patients with BMS/DES-ISR. The primary endpoints were the angiographic outcomes, including the minimal luminal diameter (MLD), diameter stenosis %(DS%), late lumen loss (LLL), and binary restenosis (BR). Results A total of six randomized clinical trials with 1177 BMS/DES-ISR patients were included in our meta-analysis. For angiographic outcomes, there were significantly less MLD and more DS% with DEB compared to new-generation DES (MLD: MD =?0.18, 95% CI:?0.31– ?0.04, P < 0.001;DS%: MD = 5.68, 95% CI: 1.00–10.37, P < 0.001). Moreover, for one-year clinical outcomes, DEB was associated with a significant increase risk in target lesion revascularization (TLR)(RR = 2.93, 95% CI: 1.50–5.72, P = 0.002). However, DEB was associated with higher risks of major adverse cardiac event, target vessel revascularization, TLR, BR, and more DS% only in DES-ISR group. Conclusions DEB and new-generation DES have the similar clinical efficacy for the treatment of BMS-ISR. However, DES showed more MLD, less DS%, and a decreased risk of TLR for the treatment of DES-ISR.

Influence of increased epicardial adipose tissue volume on 1-year in-stent restenosis in patients who received coronary stent implantation

Background Epicardial adipose tissue （EAT） is significantly associated with the formation and composition of coronary atherosclerotic plaque, cardiac events and the clinical prognosis of coronary heart disease. But, whether increased EAT deposition may affect the incidence of in-stent restenosis （ISR） is currently unclear. This study used coronary computed tomography angiography （CCTA） as a mean to investigate whether increased EAT volume was associated with ISR. Methods A total of 364 patients who underwent 64-slice CCTA examination for the evaluation of suspected coronary artery disease, and subsequently underwent percutaneous coronary intervention （PCI） for the first time, and then accepted coronary angiography （CA） follow-up for ISR examination in one year, were retrospectively included in this study. EAT volume was measured by CCTA examination. CA follow-up was obtained between 9 and 15 months. ISR was defined as 〉 50% kuninal diameter narrowing of the stent segment or peri-stent segment. EAT volume was compared between patients with and without ISR and additional well-known predictors of ISR were compared. Results EAT volume was significantly increased in patients with ISR compared with those without ISR （154.5 ± 74.6 mL vs. 131.0 ± 52.2 mL, P 〈 0.001）. The relation between ISR and EAT volume remained significant after adjustment for conventional cardiovascular risk factors and angiographic parameters. Conclusions EAT volume was related with ISR and may provide additional information for future ISR.

Increased serum TREM-1 level is associated with in-stent restenosis,and activation of TREM-1 promotes inflammation,proliferation and migration in vascular smooth muscle cells

Background and Objective In-stent restenosis(ISR)remains a major limitation of percutaneous coronary intervention despite improvements in stent design and pharmacological agents,whereas the mechanism of ISR has not been fully clarified.In the present study,we sought to investigate the potential association of serum soluble TREM-1(sTREM-1)levels with the incidence of ISR.The role of TREM-1 was evaluated in cultured vascular smooth muscle cells(VSMCs).

Local drug-delivery balloon for proliferative occlusive in-stent restenosis after drug-eluting stent

Drug-coated balloon has been developed as an alternative to drug-eluting stents for in-stent restenosis but the performance of drug infusion balloon in such setting has not been previously described. We present a case of particularly aggressive in-stent restenosis after drug eluting stent implantation treated with a new kind of drug infusion balloon developed in order to overcome the impossibility to inflate regular drug-coated balloon for several dilatation.

Volumetric intravascular ultrasound comparisons of drug-eluting stent thrombosis and in-stent restenosis

Objectives We compared intravascular ultrasound (IVUS) findings of drug-eluting stent (DES)-treated lesions that developed stent thrombosis versus in-stent restenosis (ISR) to identify underlying mechanical differences. Methods IVUS findings in 15 post-DES thrombosis patients were compared with 45 matched ISR patients who had no evidence of stent thrombosis. Results Minimum stent area [MSA, (3.7±0.8) mm2 vs (4.9±1.8) mm2, P=0.01], minimum stent diameter [(1.9±0.3) mm vs (2.3±0.4) mm, P=0.005], mean stent area [(5.2±0.8) mm2 vs (7.2±2.1) mm2, P【0.01], and both focal [MSA/reference lumen area, (54.7±15.9)% vs (75.0±20.1)%, P=0.001] and diffuse stent expansion [mean stent area/reference lumen area, (76.6±23.0)% vs (110.3±23.3)%, P【0.01] were significantly smaller in the stent thrombosis group (vs the ISR group). An MSA 【4.0 mm2 (73.3% vs 35.6%, P=0.01) or 【5.0 mm2 (86.7% vs 53.3%, P=0.02) was more often found in the stent thrombosis group (vs the ISR group). The MSA site occurred more frequently in the proximal stent segment within the stent thrombosis group compared to the ISR group (60% vs 24.4%, P=0.01). There were no differences in edge dissection, stent fracture, or stent-vessel wall malapposition between the two groups. Independent predictors of stent thrombosis were diffuse stent expansion (OR=1.5, P=0.03) and proximal location of the MSA site (OR=12.7, P=0.04). Conclusion DES-treated lesions that develop thrombosis or restenosis are often underexpanded. Underexpansion appears to be more severe in DES-thrombosis lesions. Lesions with diffuse underexpansion and a proximal (vs distal) underexpanded MSA site are more predisposed to thrombus formation than ISR.

Fasting Blood Glucose but not TMAO is Associated with in-Stent Restenosis in Patients with Acute Coronary Syndrome

Background:The purpose of our study was to assess whether the occurrence of ISR might be associated with plasma TMAO levels in patients with ACS after DES implantation.Methods:This was a single center retrospective case-control study,in which 64 symptomatic patients with repeated coronary angiography after PCI and 15 patients with ISR were included in the ISR group,and 49 patients without ISR were included in the non-ISR group.High-performance liquid chromatography with tandem mass spectrometry was used to measure plasma TMAO levels.Results:No significant differences were observed in plasma TMAO between the ISR and non-ISR groups.Plasma TMAO levels showed no significant correlation with ISR,but were significantly positively correlated with diabetes mellitus,serum HbA1c levels and serum creatinine levels;moreover,they were significantly negatively correlated with female sex.ISR was significantly positively correlated with diabetes mellitus,fasting blood glucose levels,the neutro-phil to lymphocyte ratio and syntax score;in addition,it was significantly negatively correlated with platelets.Logistic regression analysis indicated that fasting blood glucose was the only independent predictor of ISR.Conclusion:Plasma TMAO may not be associated with ISR and plaque burden in patients with ACS after DES im-plantation,whereas FBG may predict the development of ISR in these patients.

Clinical study about the effect of Simiao Yong'an Decoction on preventing in-stent restenosis and regulating inflammation and oxidative stress after lower extremity stent angioplasty stenting

Objective:To study the effect of Simiao Yong'an Decoction on the prevention of in-stent restenosis and the regulation of inflammation and oxidative stress after lower extremity stent angioplasty.Methods:A prospective study was conducted on 60 ASO patients who underwent lower extremity stent angioplasty in our hospital between January 2014 and January 2018.The patients were randomly divided into observation group receiving postoperative Simiao Yong'an Decoction combined with antiplatelet drug treatment and control group receiving postoperative antiplatelet drug treatment.The conditions of in-stent restenosis were followed up,and the indicators of coagulation,inflammation and oxidative stress were detected.Results:The incidence of in-stent restenosis in observation group 1 year after operation was significantly lower than that in control group;6 months and 12 months after operation,the ankle brachial index(ABI)levels,minimal lumen diameter(MLD)levels at the stent and superoxide dismutase(SOD)contents of observation group were significantly higher than those of control group,whereas D-dimer(D-D)and fibrinogen degradation product(FDP)levels as well as P-selectin,C-reactive protein(CRP),tumor necrosis factor-α(TNF-α),malondialdehyde(MDA)and inducible nitric oxide synthase(iNOS)contents were significantly lower than those of control group.Conclusions:Simiao Yong'an Decoction can prevent the in-stent restenosis and inhibit the inflammation and oxidative stress after lower extremity stent angioplasty.

Influence of Simvastatin for In-stent Restenosis Rate and Blood Lipid Level and Inflammation Actor after Coronary Artery Stent Implantation

Objectives To investigate the effect of simvastatin on the probability of restenosis after stent implantation and serum level of lipids as well as high-sensitivity C-reactive protein (hs-CRP) in patients with coronary heart disease (CHD). Methods 118 patients with CHD after stenting therapy were divided into treatment group (n=62) and control group (n=56) randomly. All patients were treated with aspirin (100 mg/d) and clopidogrel (75 mg/d) while treatment group patients took simvastatin (40 mg qn) additionally. All patients underwent coronary angiography (CAG) to compare the difference of restenosis and the serum level of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), triglyceride (TG) as well as hs-CRP after the drug treatment for 6 months. Results The probability of restenosis was significantly lower in the treatment group than that of control group (P<0.01) and the results were similar between the patients with bare metal stent (P<0.01) and those with sirolimus-eluting stent (P<0.01). The serum levels of TC (P<0.01), LDL-c (P<0.01), TG (P<0.05) and hs-CRP (P<0.01) were obviously lower while the HDL-c (P<0.05) level was higher in the treatment group than those of control group. There was no death case. Conclusions Simvastatin could decrease the probability of restenosis significantly after coronary stent implantation with dose of 40 mg/d. It also has good performance on lipids control and lightening inflammatory reactions with its undoubtedly safety.

Diagnosis and management of hepatic artery in-stent restenosis after liver transplantation by optical coherence tomography:A case report

BACKGROUNDPercutaneous transluminal angioplasty and stenting represent an effectivetreatment for hepatic artery stenosis after liver transplantation. In the first yearafter stenting, approximately 22% of patients experience in-stent restenosis,increasing the risk of artery thrombosis and related complications, and 50%experience liver failure. Although angiography is an important tool for diagnosisand the planning of therapeutic interventions, it may raise doubts, especially insmall-diameter arteries, and it provides low resolution rates compared withnewer intravascular imaging methods, such as optical coherence tomography(OCT).CASE SUMMARYA 64-year-old male developed hepatic artery stenosis one year after orthotropicliver transplantation and was successfully treated with percutaneous transluminalangioplasty with stenting. Five months later, the Doppler ultrasound resultsindicated restenosis. Visceral arteriography confirmed hepatic artery tortuositybut was doubtful for significant in-stent restenosis (ISR) and intrahepatic flowreduction. To confirm ISR, identify the etiology and guide treatment, OCT wasperformed. OCT showed severe stenosis due to four mechanisms: Focal andpartial stent fracture, late stent malapposition, in-stent neointimal hyperplasia,and neoatherosclerosis.CONCLUSIONIntravascular diagnostic methods can be useful in evaluating cases in which initialangiography results are not sufficient to provide a proper diagnosis of significantstenosis, especially with regard to ISR. A wide range of diagnoses are provided byOCT, resulting in different treatment options. Interventional radiologists shouldconsider intravascular diagnostic methods as additional tools for evaluatingpatients when visceral angiography results are unclear.

Preventive role of palladium-103 radioactive stent on in-stent restenosis in rabbit iliac arteries

The abilility of γ-emitting palladium-103 stent implantation to inhibit in-stent restenosis in rabbit iliac ar- teries was investigated. Quantitative histomorphometry of the stented iliac segments 28 days after the implantation indicated that palladium-103 stents made a significant reduction in neointimal area and percent area stenosis com- pared with the nonradioactive stents. Lumen area in the palladium-103 stents treatment group was larger than the control group. However, the reduction of neointima formation by palladium-103 stents implantation was in a non-dose-dependent fashion. Low ionizing radiation doses via γ-emitting palladium-103 stent are effective in pre- venting neointimal hyperplasia in iliac arteries of rabbits. Palladium-103 stents can be employed as a possible novel means to prevent in-stent restenosis.