Modifying effect of dual antiplatelet therapy on incidence of stent thrombosis according to implanted drug-eluting stent type.

AIM: To investigate the putative modifying effect of dual antiplatelet therapy (DAPT) use on the incidence of stent thrombosis at 3 years in patients randomized to Endeavor zotarolimus-eluting stent (E-ZES) or Cypher sirolimus-eluting stent (C-SES). METHODS AND RESULTS: Of 8709 patients in PROTECT, 4357 were randomized to E-ZES and 4352 to C-SES. Aspirin was to be given indefinitely, and clopidogrel/ticlopidine for ≥3 months or up to 12 months after implantation. Main outcome measures were definite or probable stent thrombosis at 3 years. Multivariable Cox regression analysis was applied, with stent type, DAPT, and their interaction as the main outcome determinants. Dual antiplatelet therapy adherence remained the same in the E-ZES and C-SES groups (79.6% at 1 year, 32.8% at 2 years, and 21.6% at 3 years). We observed a statistically significant (P = 0.0052) heterogeneity in treatment effect of stent type in relation to DAPT. In the absence of DAPT, stent thrombosis was lower with E-ZES  vs. C-SES (adjusted hazard ratio 0.38, 95% confidence interval 0.19, 0.75; P = 0.0056). In the presence of DAPT, no difference was found (1.18; 0.79, 1.77; P = 0.43). CONCLUSION: A strong interaction was observed between drug-eluting stent type and DAPT use, most likely prompted by the vascular healing response induced by the implanted DES system. These results suggest that the incidence of stent thrombosis in DES trials should not be evaluated independently of DAPT use, and the optimal duration of DAPT will likely depend upon stent type (Clinicaltrials.gov number NCT00476957).

Long-term clinical outcome after sirolimus-stent implantation for in sirolimus-eluting stent restenosis

Rapport de synthèse : But: la resténose intra-stent au sirolimus (SAS) reste un problème clinique. Parmi tes diverses approches thérapeutiques disponibles aujourd'hui aucune n'a la primauté car tes résultats à moyen terme restent relativement médiocres. Méthodologie: les patients souffrant d'une resténose intra-SAS chez lesquels un second SAS a été implanté comme traitement de cette resténose ont été inclus dans ce registre. Lors d'ischémie clinique ou électrique après implantation d'un SAS les malades chez lesquels l'angioplastie au ballon seul ne donnait pas un résultat satisfaisant ont bénéficié de l'implantation d'un stent actif dans un stent actif. Résultats: vingt-sept patients sont inclus dans ce registre. La resténose était de type focale dans 34% des cas, diffuse dans 59% des cas et proliférative dans 7% des cas. La procédure a été un succès chez tous les patients sans complications aiguës durant l'hospitalisation. A 14±7 mois, on dénombre 8 (30%) événements cardiaques majeurs (1 mort, 1 infarctus du myocarde, 4 revascularisations additionnelles de la lésion, 1 revascularisation additionnelle du vaisseau cible). Un patient a subi un pontage aorto-coronarien. Dix-neuf patients (70%) ont évolué sans aucun problème. Conclusion: en conclusion, l'implantation d'un SAS pour traiter une resténose intra-SAS est réalisable avec un très bon résultat immédiat. Cependant, l'incidence d'un événement cardiaque majeur reste élevée à long terme.

Budd-Chiari syndrome due to prothrombotic disorder: mid-term patency and efficacy of endovascular stents.

Our objective was to evaluate efficacy and patency of metallic stent placement for symptomatic Budd-Chiari syndrome (BCS) due to prothrombotic disorders. Eleven patients with proved BCS due to prothrombotic disorders were referred for endovascular treatment because of refractory ascites (n=9), abdominal pain (n=8), jaundice (n=6), and/or gastrointestinal bleeding (n=4). Stents were inserted for stenosed hepatic vein (n=7), inferior vena cava (n=2), or mesenterico-caval shunt (n=2). Clinical efficacy and stent patency was evaluated by clinical and Doppler follow-up. After a mean follow-up of 21 months, 6 patients had fully patent stents without reintervention (primary stent patency: 55%). Two patients with hepatic vein stenosis had stent thrombosis and died 4 months after procedure. Restenosis occurred in 3 cases (2 hepatic vein and 1 mesenterico-caval shunt stenosis) and were successfully treated by balloon angioplasty (n=2) and addition of new stents (n=1) leading to a 82% secondary stent patency. Of 9 patients with patent stent, 7 were asymptomatic (77%) at the end of the study. Stent placement is a safe and effective procedure to control of symptomatic BCS. Prothrombotic disorder does not seem to jeopardize patency in anticoagulated patients.

Malignant gastroduodenal obstruction: palliation with self-expanding metallic stents.

PURPOSE: To evaluate the feasibility, efficacy, and tolerance of self-expanding metallic stent insertion under fluoroscopic guidance for palliation of symptoms related to malignant gastroduodenal obstruction. MATERIALS AND METHODS: Seventy-two patients (38 men, 34 women) aged 25-98 years (mean, 62 years) with duodenal (n = 43), antropyloric (n = 13), surgical gastrojejunostomy (n = 10), or pyloroduodenal (n = 6) malignant obstruction were referred for insertion of self-expanding metallic stents over a 6-year period. Stent insertion was performed with use of a peroral or transgastric approach when necessary (n = 11). RESULTS: Stents were successfully inserted in 70 of the 72 patients (97%) and provided symptom relief in 65 patients (90%). Inserted stents were mainly uncovered vascular (n = 55) or enteral (n = 10) Wallstents. One hundred eight stents were initially inserted: one, two, three, or four stents were indicated in 43, 17, nine, and one patient, respectively. Mean follow-up was 119 days (range, 4-513 days). Mean stent patency was 113 days (range, 4-513 days). Mean survival of patients was 120 days. During follow-up, stent obstruction occurred in seven patients as a result of tumoral overgrowth (n = 5) or ingrowth (n = 2). Complications occurred in 12 of the 72 patients (17%), including stent migration (n = 8), stent fracture (n = 1), duodenal perforation (n = 1), and death related to general anesthesia (n = 1). CONCLUSION: Despite a significant complication rate, self-expanding metallic stent insertion under fluoroscopic guidance appears to be a feasible and useful technique in the palliative management of malignant gastroduodenal obstruction.

Microwave spectrometry for the Evaluation of the structural integrity of metallic stents

Purpose: To assess the feasibility of a method based on microwave spectrometry to detect structural distortions of metallic stents in open air conditions and envisage the prospects of this approach toward possible medical applicability for the evaluation of implanted stents. Methods: Microwave absorbance spectra between 2.0 and 18.0 GHz were acquired in open air for the characterization of a set of commercial stents using a specifically design setup. Rotating each sample over 360º, 2D absorbance diagrams were generated as a function of frequency and rotation angle. To check our approach for detecting changes in stent length (fracture) and diameter (recoil), two specific tests were performed in open air. Finally, with a few adjustments, this same system provides 2D absorbance diagrams of stents immersed in a water-based phantom, this time over a bandwidth ranging from 0.2 to 1.8 GHz. Results: The authors show that metallic stents exhibit characteristic resonant frequencies in their microwave absorbance spectra in open air which depend on their length and, as a result, may reflect the occurrence of structural distortions. These resonances can be understood considering that such devices behave like dipole antennas in terms of microwave scattering. From fracture tests, the authors infer that microwave spectrometry provides signs of presence of Type I to Type IV stent fractures and allows in particular a quantitative evaluation of Type III and Type IV fractures. Recoil tests show that microwave spectrometry seems able to provide some quantitative assessment of diametrical shrinkage, but only if it involves longitudinal shortening. Finally, the authors observe that the resonant frequencies of stents placed inside the phantom shift down with respect to the corresponding open air frequencies, as it should be expected considering the increase of dielectric permittivity from air to water. Conclusions: The evaluation of stent resonant frequencies provided by microwave spectrometry allows detection and some quantitative assessment of stent fracture and recoil in open air conditions. Resonances of stents immersed in water can be also detected and their characteristic frequencies are in good agreement with theoretical estimates. Although these are promising results, further verifica tion in a more relevant phantom is required in order to foresee the real potential of this approach.

Disseny i desenvolupament d’un sistema tecnològic de fabricació de “stents” cardiovasculars mitjançant làser

Els stents són unes pròtesis endovasculars. L’objectiu del projecte és el disseny i desenvolupament d’un utillatge que permeti la seva fabricació per tall làser. S’utilitzarà el làser del GREP (Grup de Recerca en Enginyeria de Producte, Procés i Producció) de la Universitat de Girona, el qual està instal•lat sobre el capçal d’un centre de mecanitzat convencional

Self-expandable metal stents in the treatment of acute esophageal variceal bleeding.

Acute variceal bleeding (AVB) is a life-threatening complication in patients with cirrhosis. Hemostatic therapy of AVB includes early administration of vasoactive drugs that should be combined with endoscopic therapy, preferably banding ligation. However, failure to control bleeding or early rebleed within 5 days still occurs in 15-20% of patients with AVB. In these cases, a second endoscopic therapy may be attempted (mild bleeding in a hemodynamically stable patient) or we can use a balloon tamponade as a bridge to definitive derivative treatment (i.e., a transjugular intrahepatic portosystemic shunt). Esophageal balloon tamponade provides initial control in up to 80% of AVB, but it carries a high risk of major complications, especially in cases of long duration of tamponade (>24 h) and when tubes are inserted by inexperienced staff. Preliminary reports suggest that self-expandable covered esophageal metallic stents effectively control refractory AVB (i.e., ongoing bleeding despite pharmacological and endoscopic therapy or massive bleeding precluding endoscopic therapy) with a low incidence of complications. Thus, covered self-expanding metal stents may represent an alternative to the Sengstaken-Blakemore balloon for the temporary control of bleeding in treatment failures. Further studies are required to determine the role of this new device in AVB.

Microwave spectrometry for the Evaluation of the structural integrity of metallic stents

Purpose: To assess the feasibility of a method based on microwave spectrometry to detect structural distortions of metallic stents in open air conditions and envisage the prospects of this approach toward possible medical applicability for the evaluation of implanted stents. Methods: Microwave absorbance spectra between 2.0 and 18.0 GHz were acquired in open air for the characterization of a set of commercial stents using a specifically design setup. Rotating each sample over 360º, 2D absorbance diagrams were generated as a function of frequency and rotation angle. To check our approach for detecting changes in stent length (fracture) and diameter (recoil), two specific tests were performed in open air. Finally, with a few adjustments, this same system provides 2D absorbance diagrams of stents immersed in a water-based phantom, this time over a bandwidth ranging from 0.2 to 1.8 GHz. Results: The authors show that metallic stents exhibit characteristic resonant frequencies in their microwave absorbance spectra in open air which depend on their length and, as a result, may reflect the occurrence of structural distortions. These resonances can be understood considering that such devices behave like dipole antennas in terms of microwave scattering. From fracture tests, the authors infer that microwave spectrometry provides signs of presence of Type I to Type IV stent fractures and allows in particular a quantitative evaluation of Type III and Type IV fractures. Recoil tests show that microwave spectrometry seems able to provide some quantitative assessment of diametrical shrinkage, but only if it involves longitudinal shortening. Finally, the authors observe that the resonant frequencies of stents placed inside the phantom shift down with respect to the corresponding open air frequencies, as it should be expected considering the increase of dielectric permittivity from air to water. Conclusions: The evaluation of stent resonant frequencies provided by microwave spectrometry allows detection and some quantitative assessment of stent fracture and recoil in open air conditions. Resonances of stents immersed in water can be also detected and their characteristic frequencies are in good agreement with theoretical estimates. Although these are promising results, further verifica tion in a more relevant phantom is required in order to foresee the real potential of this approach.

Systematic review with meta-analysis: self-expanding metal stents in patients with cirrhosis and severe or refractory oesophageal variceal bleeding.

BACKGROUND: The prognosis of patients with cirrhosis and acute variceal bleeding is very poor when the standard-of-care fails to control bleeding. New treatment modalities are needed in these patients. AIM: To synthesise the available evidence on the efficacy of self-expanding metal stents (SEMS) in patients with cirrhosis and severe or refractory oesophageal variceal bleeding. METHODS: Meta-analysis of trials evaluating SEMS in patients with cirrhosis and severe or refractory oesophageal variceal bleeding. RESULTS: Thirteen studies were included. The pooled estimate rates were 0.40 (95% confidence interval, CI = 0.31-0.49) for death, 0.41 (95% CI = 0.29-0.53) for liver-related death and 0.36 (95% CI = 0.26-0.47) for death at day 30, with low heterogeneity between studies. The pooled estimate rates were 0.12 (95% CI = 0.07-0.21) for mortality related to variceal bleeding, and 0.18 (95% CI = 0.11-0.29) for failure to control bleeding with SEMS, with no or low heterogeneity between studies. The pooled estimate rate were 0.16 (95% CI = 0.04-0.48) for rebleeding after stent removal and 0.28 (95% CI = 0.17-0.43) for stent migration, with high heterogeneity. A significant proportion of patients had access to liver transplantation or to TIPSS [pooled estimate rate 0.10 (95% CI = 0.04-0.21) and 0.26 (95% CI = 0.18-0.36), respectively]. CONCLUSIONS: Fewer than 40% of patients treated with SEMS were dead at 1 month. SEMS can be used as a bridge to TIPSS or to liver transplantation in a significant proportion of patients. Additional studies are required to identify potential risk factors leading to a poor prognosis in patients with acute variceal bleeding in whom the use of SEMS could be considered.

O uso de stents farmacológicos no tratamento da estenose das artérias vertebrais

OBJETIVO: Relatar a viabilidade e segurança da angioplastia transluminal percutânea com stents recobertos com paclitaxel para tratamento de estenose de artéria vertebral em 14 pacientes, após seguimento de dois anos. MATERIAIS E MÉTODOS: Catorze pacientes com idade média de 67,2 anos foram submetidos a tratamento endovascular mediante angioplastia percutânea e implante de stent farmacológico. O objetivo primário deste trabalho foi assegurar a segurança do procedimento. O desfecho secundário foi a eficácia clínica, definida como sintomas isquêmicos recorrentes e taxas de reestenose. RESULTADOS: O grau de estenose variou de 50% a 99% (média de 73,3% ± 10,9). A taxa de sucesso técnico da angioplastia foi de 100%. Não houve complicações diretamente relacionadas ao procedimento. Aos 24 meses de seguimento, nenhum paciente apresentou recorrência dos sintomas. A taxa de reestenose intra-stent foi de 7,1%, embora tenha sido assintomática na totalidade dos casos. CONCLUSÃO: Este estudo sugere que a angioplastia da artéria vertebral com o uso de stents recobertos com paclitaxel é uma técnica viável e promissora em termos de segurança e eficácia na prevenção da isquemia recorrente e reestenose.

Predictors of restenosis after percutaneous coronary intervention using bare-metal stents: a comparison between patients with and without dysglycemia

The objective of this study was to identify intravascular ultrasound (IVUS), angiographic and metabolic parameters related to restenosis in patients with dysglycemia. Seventy consecutive patients (77 lesions) selected according to inclusion and exclusion criteria were evaluated by the oral glucose tolerance test and the determination of insulinemia after a successful percutaneous coronary intervention (PCI) with a bare-metal stent. The degree of insulin resistance was calculated by the homeostasis model assessment of insulin resistance (HOMA-IR). Six-month IVUS and angiogram follow-up were performed. Thirty-nine patients (55.7%) had dysglycemia. The restenosis rate in the dysglycemic group was 37.2 vs 23.5% in the euglycemic group (P = 0.299). The predictors of restenosis using bivariate analysis were reference vessel diameter (RVD): £2.93 mm (RR = 0.54; 95%CI = 0.05-0.78; P = 0.048), stent area (SA): <8.91 mm² (RR = 0.66; 95%CI = 0.24-0.85; P = 0.006), stent volume (SV): <119.75 mm³ (RR = 0.74; 95%CI = 0.38-0.89; P = 0.0005), HOMA-IR: >2.063 (RR = 0.44; 95%CI = 0.14-0.64; P = 0.027), and fasting plasma glucose (FPG): ≤108.8 mg/dL (RR = 0.53; 95%CI = 0.13-0.75; P = 0.046). SV was an independent predictor of restenosis by multivariable analysis. Dysglycemia is a common clinical condition in patients submitted to PCI. The degree of insulin resistance, FPG, RVD, SA, and SV were correlated with restenosis. SV was inversely correlated with an independent predictor of restenosis in patients treated with a bare-metal stent.

Factores asociados a fenómeno de no reflujo coronario en pacientes adultos llevados a angioplastia

Introducción: La disminución de flujo en los vasos coronarios sin presencia de oclusión, es conocido como fenómeno de no reflujo, se observa después de la reperfusión, su presentación oscila entre el 5% y el 50% dependiendo de la población y de los criterios diagnósticos, dicho suceso es de mal pronóstico, aumenta el riesgo de morir en los primeros 30 días posterior a la angioplastia (RR 2,1 p 0,038), y se relaciona con falla cardiaca y arritmias, por eso al identificar los factores a los cuales se asocia, se podrán implementar terapias preventivas. Metodología: Estudio de casos y controles pareado por médico que valoró el evento, para garantizar que no existieron variaciones inter observador, con una razón 1:4 (18:72), realizado para identificar factores asociados a la presencia de no reflujo en pacientes llevados a angioplastia, entre noviembre de 2010 y mayo de 2014, en la Clínica San Rafael de Bogotá, D.C. Resultados: La frecuencia del no reflujo fue del 2.89%. El Infarto Agudo de Miocardio con elevación del ST (IAMCEST) fue la única variable que mostró una asociación estadísticamente significativa con este suceso, valor de p 0,002, OR 8,7, IC 95% (2,0 – 36,7). Discusión: El fenómeno de no reflujo en esta población se comportó de manera similar a lo descrito en la literatura, siendo el IAMCEST un factor fuertemente asociado.

Análise morfométrica digital na parede aórtica de suínos após implante de stents não revestidos versus stents revestidos com dacron

Os stents são dispositivos intravasculares implantados com o objetivo de dilatar ou fixar a placa de colesterol contra a parede arterial. O objetivo avaliar dois tipos de stents de aço inoxidável, um recoberto com poliéster (dacron) e outro não recoberto, implantados na aorta infra-renal de suínos jovens, foram avaliados por morfometria digital para medir o espessamento intimal. Foi realizado um estudo experimental randomizado, separados em dois grupos(stents não revestidos e revestidos com dacron) e duas fases (I e II). Oito stents recobertos com dacron e oito stents de aço inoxidável (30mm de extensão e 8 mm de diâmetro), não revestidos, foram implantados através de abordagem retroperitoneal na aorta infrarenal normal de 16 suínos normolipêmicos. Para a passagem do sistema de implante, foi necessário uma pequena arteriotomia na aorta distal (fase I). Após quatro semanas, a aorta com os stents foram removidas em monoblocos (fase II). Os valores de hematimetria e do lipidograma foram coletados nas duas fases e não apresentaram alterações que pudessem influenciar o estudo. Amostras de tecido dos sítios de fixação (proximal e distal) dos stents foram retiradas, confeccionadas lâminas, que foram coradas pelas técnicas de hematoxilina e eosina de Verhoeff e enviadas para análise morfométrica digital. A camada intima distal não apresentou diferença estatística significativa. A camada média proximal das porções proximal e da porção distal não apresentaram diferença entre os grupos. Os dois tipos de stents apresentaram 100% de perviedade, boa biocompatibilidade e boa incorporação a parede aórtica de suínos normolipêmicos. A camada íntima proximal do grupo de stents revestidos com dacron apresentou espessura maior do que os stents não revestidos, mas com significância estatísitica limítrofe.

Análise morfométrica da parede arterial após o implante de stent em aorta abdominal de suínos : estudo comparativo entre stents metálicos não recobertos e recobertos com politetrafluoroetileno

O espessamento intimal e a reestenose que ocorrem após os procedimentos de angioplastia transluminal percutânea e/ou o implante de stents representam uma causa freqüente de falência destes procedimentos. O principal achado patológico responsável pela reestenose parece ser a hiperplasia intimal, já que o dispositivo intravascular é resistente ao remodelamento arterial geométrico. O propósito deste estudo é avaliar, através da morfometria digital, o espessamento intimal presente nas regiões da parede arterial imediatamente proximal e distal ao implante de um stent metálico em configuração em “Z “ não recoberto ou recoberto com PTFE. Vinte e cinco suínos de raça mista, com seis a dez semanas de idade, pesando em média 20 kg foram divididos em três grupos. No grupo I, cinco animais foram submetidos à exposição cirúrgica retroperitoneal da aorta abdominal, aortotomia e manipulação com uma bainha introdutora de 12 F. O grupo II incluiu dez animais que foram submetidos ao implante de um stent metálico auto-expansível não recoberto. No grupo III, incluindo também dez animais, foram implantados stents recobertos com PTFE. Após quatro semanas, todos os animais foram sacrificados e o segmento aorto-ilíaco foi removido. Quatro animais foram excluídos do estudo por trombose da aorta (um animal do grupo II e três animais do grupo III). Para a análise morfométrica foram utilizados os testes não paramétricos de Wilcoxon e de Kruskal-Wallis, para as comparações, respectivamente, no mesmo grupo e entre os grupos. Foi adotado o nível de significância de 5% ( p< 0,05). Quando os espécimes da parede arterial, imediatamente proximal e distal aos stents foram comparados, nenhuma diferença estatisticamente significativa foi encontrada entre as áreas luminal, intimal, média ou índice intimal em cada grupo. Na comparação entre os grupos, as áreas intimal, média e o índice intimal não demonstraram variação estatisticamente significativa. Foram identificadas diferenças entre os grupos quanto às áreas luminais proximais (p = 0,036) e distais (p=0,044). Pelo teste de comparações múltiplas para Kruskal-Wallis (Teste de Dunn) identificou-se diferença significativa entre os grupos I e II. Entretanto, quando estas variáveis foram controladas pelo fator peso (relação área luminal/peso) a diferença não foi mais observada. Concluímos que, após quatro semanas, stents recobertos com PTFE induzem um espessamento intimal justa-stent similar ao observado com stents não recobertos ou com a simples manipulação arterial com uma bainha introdutora. Neste modelo experimental suíno, de curto seguimento, o revestimento com PTFE não foi responsável por adicional espessamento intimal.

Optimized Duration of Clopidogrel Therapy Following Treatment with the Endeavor Zotarolimus-Eluting Stent in Real-World Clinical Practice (OPTIMIZE) Trial: Rationale and design of a large-scale, randomized, multicenter study

Background Current recommendations for antithrombotic therapy after drug-eluting stent (DES) implantation include prolonged dual antiplatelet therapy (DAPT) with aspirin and clopidogrel >= 12 months. However, the impact of such a regimen for all patients receiving any DES system remains unclear based on scientific evidence available to date. Also, several other shortcomings have been identified with prolonged DAPT, including bleeding complications, compliance, and cost. The second-generation Endeavor zotarolimus-eluting stent (E-ZES) has demonstrated efficacy and safety, despite short duration DAPT (3 months) in the majority of studies. Still, the safety and clinical impact of short-term DAPT with E-ZES in the real world is yet to be determined. Methods The OPTIMIZE trial is a large, prospective, multicenter, randomized (1: 1) non-inferiority clinical evaluation of short-term (3 months) vs long-term (12-months) DAPT in patients undergoing E-ZES implantation in daily clinical practice. Overall, 3,120 patients were enrolled at 33 clinical sites in Brazil. The primary composite endpoint is death (any cause), myocardial infarction, cerebral vascular accident, and major bleeding at 12-month clinical follow-up post-index procedure. Conclusions The OPTIMIZE clinical trial will determine the clinical implications of DAPT duration with the second generation E-ZES in real-world patients undergoing percutaneous coronary intervention. (Am Heart J 2012;164:810-816.e3.)