Instantaneous Wave-Free Ratio for the Assessment of Intermediate Left Main Coronary Artery Stenosis: Correlations With Fractional Flow Reserve/Intravascular Ultrasound and Prognostic Implications: The iLITRO-EPIC07 Study.

BACKGROUND: There is little information available on agreement between fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) in left main coronary artery (LMCA) intermediate stenosis. Besides, several meta-analyses support the use of FFR to guide LMCA revascularization, but limited information is available on iFR in this setting. Our aims were to establish the concordance between FFR and iFR in intermediate LMCA lesions, to evaluate with intravascular ultrasound (IVUS) in cases of FFR/iFR discordance, and to prospectively validate the safety of deferring revascularization based on a hybrid decision-making strategy combining iFR and IVUS. METHODS: Prospective, observational, multicenter registry with 300 consecutive patients with intermediate LMCA stenosis who underwent FFR and iFR and, in case of discordance, IVUS and minimal lumen area measurements. Primary clinical end point was a composite of cardiovascular death, LMCA lesion-related nonfatal myocardial infarction, or unplanned LMCA revascularization. RESULTS: FFR and iFR had an agreement of 80% (both positive in 67 and both negative in 167 patients); in case of disagreement (31 FFR+/iFR- and 29 FFR-/iFR+) minimal lumen area was ≥6 mm2 in 8.7% of patients with FFR+ and 14.6% with iFR+. Among the 300 patients, 105 (35%) underwent revascularization and 181 (60%) were deferred according to iFR and IVUS. At a median follow-up of 20 months, major adverse cardiac events incidence was 8.3% in the defer group and 13.3% in the revascularization group (hazard ratio, 0.71 [95% CI 0.30-1.72]; P=0.45). CONCLUSIONS: In patients with intermediate LMCA stenosis, a physiology-guided treatment decision is feasible either with FFR or iFR with moderate concordance between both indices. In case of disagreement, the use of IVUS may be useful to indicate revascularization. Deferral of revascularization based on iFR appears to be safe in terms of major adverse cardiac events. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03767621.

Development and Evaluation of a Disease Large Animal Model for Preclinical Assessment of Renal Denervation Therapies.

New-generation catheters-based renal denervation (RDN) is under investigation for the treatment of uncontrolled hypertension (HTN). We assessed the feasibility of a large animal model of HTN to accommodate the human RDN devices. Ten minipigs were instrumented to measure blood pressure (BP) in an awake-state. HTN was induced with subcutaneous 11-deoxycorticosterone (DOCA, 100 mg/kg) implants. Five months after, the surviving animals underwent RDN with the Symplicity® system. Norepinephrine (NE) renal gradients were determined before and 1 month after RDN. Renal arteries were processed for histological (hematoxylin-eosin, Movat pentachrome) and immunohistochemical (S100, tyrosine-hydroxylase) analyses. BP significantly rose after DOCA implants. Six animals died prematurely, mainly from infectious causes. The surviving animals showed stable BP levels after 5 months. One month after RDN, nerve damage was showed in three animals, with impedance drop >10%, NE gradient drop and reduction in BP. The fourth animal showed no nerve damage, impedance drop <10%, NE gradient increase and no change in BP. In conclusion, the minipig model of DOCA-induced HTN is feasible, showing durable effects. High mortality should be addressed in next iterations of this model. RDN may partially offset the DOCA-induced HTN. Impedance drop and NE renal gradient could be markers of RDN success.

Three- and 6-month optical coherence tomographic surveillance following percutaneous coronary intervention with the Angiolite® drug-eluting stent: The ANCHOR study.

BACKGROUND: Pre-clinical results of a novel open-cell, thin strut, durable polymer, laser cut cobalt chromium sirolimus-eluting stent (Angiolite) were promising. Using quantitative optical coherence tomographic (OCT) analyses, we explored the healing characteristics of the Angiolite DES system at 3- and 6-months post implantation. METHODS: A total of 103 patients with de novo coronary lesions underwent percutaneous coronary intervention with the Angiolite DES and were randomized 1:3 into two cohorts for angiographic and OCT follow-up, with 28 and 70 patients returning for 3- or 6-month post-PCI surveillance, respectively. The primary endpoints were the 6-month rates of OCT-derived neointimal proliferation, strut coverage and incomplete strut apposition (ISA), whilst the secondary endpoints were 3-month OCT-derived measures of strut coverage and ISA, as well as 6-month quantitative coronary angiographic-derived measures [late lumen loss (LLL), binary restenosis]. RESULTS: The Angiolite stent was successfully implanted in all patients, without periprocedural complications. At 3- and 6-months follow-up, OCT strut coverage was evident in 86.3% and 83.3% of struts, mean neointimal thickness was 73.7 ± 46.5 µm and 73.9 ± 54.3 µm, mean neo-intimal area obstruction of 5.8% ±10.3% and 4.4% ± 11.3%, and ISA rates were 1.3% ± 7.3% and 1.1% ± 6.2%, respectively. In-stent LLL at 6 months was 0.07 ± 0.37 mm, with a binary in-stent angiographic restenosis rate of 0% without any stent thrombosis, myocardial infarction or cardiovascular death, with 1 patient undergoing ischemia-driven target-lesion revascularization. CONCLUSIONS: At 6 months, the Angiolite DES was safe with high rates of strut coverage, modest degrees of neointimal hyperplasia and very low rates of strut malapposition. These data coupled with the absence of in-stent binary restenosis and a very low 6-month in-stent LLL point towards an efficacious DES. Future studies are required to evaluate its efficacy in broader lesion subsets with longer follow-up.

Seguridad y eficacia de nuevos modelos de stents liberadores de sirolimus con polímero biodegradable en el modelo preclínico / Safety and efficacy of new biodegradable polymer-based sirolimus-eluting stents in a preclinical model

Introducción y objetivos: Los nuevos stents farmacoactivos (SFA), diseñados para solventar las limitaciones de los existentes, han de someterse inicialmente al análisis preclínico. El objetivo es analizar la eficacia y la seguridad de nuevos SFA con polímero biodegradable en comparación con stents convencionales (SC) y SFA comercializados en el modelo de arteria coronaria sana porcina. Métodos: Se implantaron aleatoriamente 101 stents (SC y stents liberadores de sirolimus con polímero biodegradable: 3 formulaciones test [BD1, BD2 y BD3], Orsiro, Biomime y Biomatrix) en las arterias coronarias de 34 cerdos domésticos. Se completó estudio angiográfico e histomorfométrico al mes (n = 83) y a los 3 meses (n = 18). Resultados: Los stents se implantaron en proporción stent/arteria de 1,31 ± 0,21, sin diferencias entre grupos. Al mes, los nuevos stents (BD1, BD2 y BD3) mostraron menos pérdida tardía y reestenosis angiográfica, así como menor área neointimal y reestenosis histológica (p < 0,0005) que los SC. No se observaron diferencias significativas entre los nuevos stents y los SC en endotelización, daño vascular o inflamación; solo se encontró mayor persistencia de fibrina en los nuevos (p = 0,0006). A los 3 meses, todas estas diferencias desaparecieron, excepto una menor área neointimal con el nuevo stent BD1 (p = 0,027). No hubo diferencias en ningún parámetro al mes ni a los 3 meses entre los nuevos stents y los comercializados. Conclusiones: En este modelo preclínico, los nuevos SFA con polímero biodegradable estudiados presentan menos reestenosis que los SC, sin diferencias significativas en seguridad y eficacia respecto a SFA comercializados (AU)

Introduction and objectives New drug-eluting stents (DES) designed to overcome the limitations of existing devices should initially be tested in preclinical studies. Our objective was to analyze the safety and efficacy of new biodegradable polymer-based DES compared with bare-metal stents (BMS) and commercially available DES in a model of normal porcine coronary arteries. Methods: We randomly implanted 101 stents (BMS and biodegradable polymer-based sirolimus-eluting stents: 3 test stent iterations [BD1, BD2, and BD3], Orsiro, Biomime and Biomatrix) in the coronary arteries of 34 domestic pigs. Angiographic and histomorphometric studies were conducted 1 month (n = 83) and 3 months (n = 18) later. Results: The stents were implanted at a stent/artery ratio of 1.31 ± 0.21, with no significant differences between groups. At 1 month, the new test stents (BD1, BD2 and BD3) showed less late loss and angiographic restenosis, as well as lower histologic restenosis and neointimal area (P < .0005), than the BMS. There were no differences in endothelialization, vascular injury, or inflammation between the new test stents and BMS, although the new stents showed higher fibrin deposition (P = .0006). At 3 months, all these differences disappeared, except for a lower neointimal area with the new BD1 stent (P = .027). No differences at any time point were observed between the new test stents and commercially available controls. Conclusions: In this preclinical model, the new biodegradable polymer-based DES studied showed less restenosis than BMS and no significant differences in safety or efficacy vs commercially available DES (AU)

Safety and Efficacy of New Biodegradable Polymer-based Sirolimus-Eluting Stents in a Preclinical Model.

INTRODUCTION AND OBJECTIVES: New drug-eluting stents (DES) designed to overcome the limitations of existing devices should initially be tested in preclinical studies. Our objective was to analyze the safety and efficacy of new biodegradable polymer-based DES compared with bare-metal stents (BMS) and commercially available DES in a model of normal porcine coronary arteries. METHODS: We randomly implanted 101 stents (BMS and biodegradable polymer-based sirolimus-eluting stents: 3 test stent iterations [BD1, BD2, and BD3], Orsiro, Biomime and Biomatrix) in the coronary arteries of 34 domestic pigs. Angiographic and histomorphometric studies were conducted 1 month (n = 83) and 3 months (n = 18) later. RESULTS: The stents were implanted at a stent/artery ratio of 1.31 ± 0.21, with no significant differences between groups. At 1 month, the new test stents (BD1, BD2 and BD3) showed less late loss and angiographic restenosis, as well as lower histologic restenosis and neointimal area (P < .0005), than the BMS. There were no differences in endothelialization, vascular injury, or inflammation between the new test stents and BMS, although the new stents showed higher fibrin deposition (P = .0006). At 3 months, all these differences disappeared, except for a lower neointimal area with the new BD1 stent (P = .027). No differences at any time point were observed between the new test stents and commercially available controls. CONCLUSIONS: In this preclinical model, the new biodegradable polymer-based DES studied showed less restenosis than BMS and no significant differences in safety or efficacy vs commercially available DES.

Titulares sensacionalistas: ¿también en la prensa científica? / Sensationalist headlines: also in the scientific press?

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Favorable outcomes in octogenarians treated with bioresorbable polymer drug-eluting stent.

AIM: As a result of a higher prevalence of comorbidities, elderly adults are often underrepresented in clinical trials, and more often experience complications during percutaneous coronary intervention. Our aim was to evaluate clinical outcomes of patients older than 80 years, compared with their younger counterparts, when bioresorbable polymer biolimus A9 drug-eluting stent is used for their treatment. METHODS: The prospective, observational e-Nobori registry was created to validate the safety and efficacy of bioresorbable polymer drug-eluting stent in unselected patients. The primary end-point of the study was freedom from target lesion failure defined as a composite of cardiac death, target vessel-related myocardial infarction and clinically-driven target lesion revascularization at 1 year. RESULTS: There were 781 (7.8%) octogenarians, they were less frequently male (62% vs 77%; P < 0.0001) and more often presented as acute coronary syndrome (44% vs 39%; P = 0.0182). The index percutaneous coronary intervention success was lower in the elderly patients (98% vs 99%; P = 0.0398). One-year follow up was completed for 97% of the elderly patients and 99% of the younger patients. The difference in target lesion failure (3.33% vs 2.83%; log-rank P = 0.0114) was mainly driven by increased mortality in octogenarians (3.73% vs 1.47%; P < 0.0001). Elderly patients had more bleeding and vascular complications (2.67% vs 1.05%; P = 0.0001). CONCLUSIONS: Despite advanced age, multiple comorbidities and complexity of treated lesions, clinical outcomes are favorable in octogenarians treated by bioresorbable polymer biolimus A9 drug-eluting stent. Geriatr Gerontol Int 2016; 16: 1246-1253.

Seguridad y eficacia de nuevos modelos de stents liberadores de sirolimus en el modelo preclínico / Safety and efficacy of new sirolimus-eluting stent models in a preclinical study

Introducción y objetivos: En el proceso de mejora de los polímeros, las plataformas y los sistemas de liberación de fármacos en los nuevos diseños de stents farmacoactivos, el análisis preclínico inicial es obligatorio. El objetivo es analizar la eficacia y la seguridad de nuevos modelos de stentsfarmacoactivos en comparación con un stent convencional y stents farmacoactivos comercializados en el modelo experimental de arteria coronaria sana porcina. Métodos: Se implantaron aleatoriamente 60 stents (stent convencional, nuevos stents liberadores de sirolimus: stents liberadores de fármaco 1, 2 y 3; Cypher® y Xience®) en las arterias coronarias de 20 cerdos domésticos raza Large White. Se realizó estudio angiográfico e histomorfométrico a los 28 días. Resultados: Los stents se implantaron en proporción stent/arteria de 1,34 ± 0,15, sin diferencias significativas entre grupos. Los nuevos stents mostraron menos pérdida tardía y restenosis angiográfica que los convencionales (p = 0,006 y p < 0,001 respectivamente). Todas las nuevas plataformas presentaron menos área neointimal y restenosis histológica que losstents convencionales (p < 0,001 para cada variable), sin diferencias con los farmacoactivos comercializados. En cuanto a la seguridad, todos los stents farmacoactivos mostraron menos endotelización que los convencionales, salvo el stent liberador de fármaco 3 (p = 0,084). Asimismo, la inflamación observada fue menor con el stent liberador de fármaco 3 que con los demás. Conclusiones: Las nuevas plataformas de stents farmacoactivos estudiadas se asocian con menos restenosis que los convencionales, sin diferencias significativas en seguridad y eficacia respecto a los stents farmacoactivos comercializados (AU)

Introduction and objectives: Initial preclinical studies are required during the process of improving polymers, platforms, and drug-eluting systems for new coronary stent designs. Our objective was to analyze the efficacy and safety of new drug-eluting stent models compared with a conventional stent and commercialized drug-eluting stents in an experimental model with healthy porcine coronary arteries. Methods: Sixty stents (conventional stent, new sirolimus-eluting stents: drug-eluting stents 1, 2 and 3; Cypher® and Xience®) were randomly placed in the coronary arteries of 20 Large White domestic pigs. Angiographic and histomorphometric studies were done 28 days later. Results: The stents were implanted at a stent/artery ratio of 1.34 ± 0.15, with no significant differences between groups. The new stents showed less late loss and angiographic restenosis than conventional stents (P = .006 and P < .001, respectively). Histologically, restenosis and neointimal area were lower with all the new platforms than with the conventional stents (P < .001 for each variable), and no differences were found vs the drug-eluting stents on the market. Safety data showed that endothelialization was lower with drug-eluting stents than with conventional stents, except for drug-eluting stent 3 (P = .084). Likewise, inflammation was lower with drug-eluting stent 3 than with other stents. Conclusions: The new drug-eluting stent platforms studied are associated with less restenosis than conventional stents and showed no significant differences in safety or efficacy vs commercialized drug-eluting stents (AU)

Safety and Efficacy of New Sirolimus-eluting Stent Models in a Preclinical Study.

INTRODUCTION AND OBJECTIVES: Initial preclinical studies are required during the process of improving polymers, platforms, and drug-eluting systems for new coronary stent designs. Our objective was to analyze the efficacy and safety of new drug-eluting stent models compared with a conventional stent and commercialized drug-eluting stents in an experimental model with healthy porcine coronary arteries. METHODS: Sixty stents (conventional stent, new sirolimus-eluting stents: drug-eluting stents 1, 2 and 3; Cypher(®) and Xience(®)) were randomly placed in the coronary arteries of 20 Large White domestic pigs. Angiographic and histomorphometric studies were done 28 days later. RESULTS: The stents were implanted at a stent/artery ratio of 1.34±0.15, with no significant differences between groups. The new stents showed less late loss and angiographic restenosis than conventional stents (P=.006 and P<.001, respectively). Histologically, restenosis and neointimal area were lower with all the new platforms than with the conventional stents (P<.001 for each variable), and no differences were found vs the drug-eluting stents on the market. Safety data showed that endothelialization was lower with drug-eluting stents than with conventional stents, except for drug-eluting stent 3 (P=.084). Likewise, inflammation was lower with drug-eluting stent 3 than with other stents. CONCLUSIONS: The new drug-eluting stent platforms studied are associated with less restenosis than conventional stents and showed no significant differences in safety or efficacy vs commercialized drug-eluting stents.

Análisis de la eficacia y la seguridad de distintos balones liberadores de paclitaxel en un modelo animal / Safety and Efficacy of Different Paclitaxel-eluting Balloons in a Porcine Model

Introducción y objetivos Los balones liberadores de paclitaxel tienen demostrada eficacia en el tratamiento y la prevención de la restenosis. Sin embargo, no todos los dispositivos comercializados son igualmente efectivos; por ello es importante comparar los resultados en un modelo preclínico. Nuestro objetivo es analizar la seguridad y la eficacia preclínicas de distintos dispositivos. Métodos En 17 cerdos domésticos (25 ± 3 kg) se implantaron 51 stents metálicos (Architect®, iVascular), uno en cada rama coronaria principal, y se sobredilataron con distintos balones de control (n = 10) o liberadores de paclitaxel: balón liberador de paclitaxel 1 (iVascular) (n = 15); balón liberador de paclitaxel 2 (iVascular) (n = 16) e In. Pact Falcon® (Medtronic) (n = 10). Tras 28 días, se analizaron los resultados de restenosis (angiografía e histomorfometría) y de reparación vascular: daño vascular, endotelización, persistencia de fibrina e inflamación. Resultados Los distintos balones liberadores de paclitaxel mostraron valores similares de estenosis en el seguimiento significativamente menores que los controles: angiografía, el 9 ± 12% frente al 34 ± 18% (p < 0,0001); histomorfometría, el 22 ± 8% frente al 51 ± 18% (p < 0,0001). Los grados de daño vascular (0,6 ± 0,5) e inflamación (0,8 ± 0,3) fueron bajos, sin diferencias entre los grupos. Los marcadores del efecto farmacológico fueron significativamente distintos entre los dispositivos liberadores de paclitaxel (sin diferencias entre ellos) y los controles: superficie endotelizada, el 87 ± 10% frente al 99 ± 2% (p = 0,0007); grado de fibrina, 2,1 ± 0,7 frente a 0,4 ± 0,5 (p < 0,0001). No hubo diferencias entre los distintos balones liberadores de paclitaxel. Conclusiones: En este modelo preclínico, los balones liberadores de paclitaxel analizados mostraron una reducción significativa de la restenosis. Aunque no se observaron datos de daño vascular o inflamación persistentes, sí se apreciaron los efectos de la acción farmacológica en forma de endotelización retrasada y acumulación de fibrina

Introduction and objectives Paclitaxel-eluting balloons have shown high antiproliferative efficacy in the treatment and prevention of restenosis. Nevertheless, not all available devices are equally effective, which makes it interesting to compare results in a preclinical model. Our objective was to assess the preclinical efficacy and safety of different devices. Methods We implanted 51 metallic stents (Architect®, iVascular) in 17 domestic swine (mean, 25 [3] kg), inserting 1 stent per major coronary artery. Stent postdilatation was performed with different control balloons (n = 10) or paclitaxel-eluting balloons: paclitaxel-eluting balloon 1 (iVascular) (n = 15); paclitaxel-eluting balloon 2 (iVascular) (n = 16) and In.Pact Falcon®(Medtronic) (n = 10). The restenosis rate (using angiography and histomorphometry) and vascular healing parameters (balloon-related vascular injury score, endothelialization rate, and fibrin and inflammation scores) were analyzed at 28 days. Results The distinct paclitaxel-eluting balloons showed a similar degree of stenosis at follow-up, which was significantly lower than that in the control group: diameter stenosis was 9% (12%) vs 34% (18%) by angiography (P < .0001) and was 22% (8%) vs 51% (18%) by histomorphometry (P < .0001). Scores for vascular injury (mean, 0.6 [0.5]) and inflammation (mean, 0.8 [0.3]) were uniformly low across all groups. Drug effect markers differed significantly between the paclitaxel-eluting balloons and control groups, with lower endothelialization rates (87% [10%] vs 99% [2%]; P = .0007) and higher fibrin scores (2.1 [0.7] vs 0.4 [0.5]; P < .0001) in the paclitaxel-eluting balloons groups. There were no differences between the different paclitaxel-eluting balloons. Conclusions: In this preclinical model, the paclitaxel-eluting balloons studied significantly reduced in-stent restenosis compared with the control balloons. Although there were no findings of persistent vascular injury or inflammation, delayed endothelialization and fibrin aggregate suggest a drug deposition response

Safety and efficacy of different paclitaxel-eluting balloons in a porcine model.

INTRODUCTION AND OBJECTIVES: Paclitaxel-eluting balloons have shown high antiproliferative efficacy in the treatment and prevention of restenosis. Nevertheless, not all available devices are equally effective, which makes it interesting to compare results in a preclinical model. Our objective was to assess the preclinical efficacy and safety of different devices. METHODS: We implanted 51 metallic stents (Architect(®), iVascular) in 17 domestic swine (mean, 25 [3] kg), inserting 1 stent per major coronary artery. Stent postdilatation was performed with different control balloons (n=10) or paclitaxel-eluting balloons: paclitaxel-eluting balloon 1 (iVascular) (n=15); paclitaxel-eluting balloon 2 (iVascular) (n=16) and In.Pact Falcon(®) (Medtronic) (n=10). The restenosis rate (using angiography and histomorphometry) and vascular healing parameters (balloon-related vascular injury score, endothelialization rate, and fibrin and inflammation scores) were analyzed at 28 days. RESULTS: The distinct paclitaxel-eluting balloons showed a similar degree of stenosis at follow-up, which was significantly lower than that in the control group: diameter stenosis was 9% (12%) vs 34% (18%) by angiography (P<.0001) and was 22% (8%) vs 51% (18%) by histomorphometry (P<.0001). Scores for vascular injury (mean, 0.6 [0.5]) and inflammation (mean, 0.8 [0.3]) were uniformly low across all groups. Drug effect markers differed significantly between the paclitaxel-eluting balloons and control groups, with lower endothelialization rates (87% [10%] vs 99% [2%]; P=.0007) and higher fibrin scores (2.1 [0.7] vs 0.4 [0.5]; P<.0001) in the paclitaxel-eluting balloons groups. There were no differences between the different paclitaxel-eluting balloons. CONCLUSIONS: In this preclinical model, the paclitaxel-eluting balloons studied significantly reduced in-stent restenosis compared with the control balloons. Although there were no findings of persistent vascular injury or inflammation, delayed endothelialization and fibrin aggregate suggest a drug deposition response.

Investigación traslacional en isquemia, infarto de miocardio y reperfusión / Translational research in myocardial ischemia, infarction and reperfusion

Desde los modelos de corazón aislado ex vivo hasta los de oclusión de arterias coronarias por técnicas quirúrgicas o endovasculares en animales, la investigación preclínica se ha desarrollado en los distintos aspectos de la isquemia, la necrosis y la reperfusión del miocardio. En el campo de la isquemia cardiaca, estos ensayos han permitido desarrollar múltiples vías de tratamiento eficaces en su posterior uso clínico. Las estrategias de recanalización de la arteria ocluida que causa el infarto, aplicadas cuanto antes mejor («tiempo es músculo»), son las principales armas para reducir el tamaño de la necrosis, con un impacto positivo en el pronóstico posterior. Sin embargo, la propia reperfusión causa un daño que agrava las consecuencias del infarto. Muchas terapias contra el daño por reperfusión se han ensayado con éxito en modelos animales (distintos tratamientos farmacológicos o formas de condicionamiento cardiaco), pero no se han demostrado eficaces en su posterior aplicación clínica. La explosión de la medicina regenerativa ha sido particularmente importante en el terreno cardiovascular, y su desarrollo exige el mejor banco de pruebas preclínico posible. El continuo perfeccionamiento de estos modelos animales persigue encontrar el modelo perfecto, aquel que reproduzca cada una de las características que observamos en la biología y la patología humanas (AU)

Preclinical research into all aspects of myocardial ischemia, infarction and reperfusion has made use of a range of models, from ex vivo models of the isolated beating heart to animal models of coronary artery occlusion produced using surgical or endovascular techniques. In the area of cardiac ischemia, such research has led to the development of several forms of treatment that were subsequently found to be effective in patients. The principle tools for reducing the extent of myocardial necrosis, and thereby improving prognosis, comprise different techniques for recanalization of the occluded artery responsible for an infarction, all of which must be implemented as soon as possible (‘time is muscle'). However, reperfusion can itself result in injury that exacerbates the effects of an infarction. A number of ways of limiting reperfusion injury have been tested successfully in animal models (e.g. various pharmacological treatments and different forms of myocardial conditioning) but none has proven effective when applied clinically. The recent explosion of interest in regenerative medicine has been particularly important in the area of cardiovascular disease, and future development will require the best possible set of preclinical tests. Animal models continue to be refined, with the ultimate goal being the perfect model that replicates all aspects of human biology and pathology (AU)

Resonancia magnética cardiaca en modelos animales / Cardiac magnetic resonance imaging in animal models

La resonancia magnética se ha erigido en la técnica de elección para el diagnóstico y manejo de múltiples enfermedades. En el campo cardiaco permite alcanzar una precisión muy alta en la cuantificación y la caracterización tisular gracias a su elevada resolución espacial y temporal a la vez que permite una muy buena caracterización tisular. Por ello, su aplicación a la investigación traslacional resulta clave en la valoración de muchos de los resultados. En este original se revisan las aplicaciones de la técnica en distintos modelos animales, desde los más pequeños hasta el más empleado en la investigación cardiovascular traslacional, el porcino. Se analizan los distintos medios de contraste empleados y se sistematizan los estudios cardiacos para la obtención de los mejores resultados anatómicos y funcionales (AU)

Magnetic resonance imaging is now established as the gold standard for the diagnosis and management of a range of diseases. In cardiology, the technique’s high spatial and temporal resolution makes it possible to quantify and characterize anatomical structures with great precision. Consequently, it has played a key role in evaluating the results of translational research. This article contains a review of the application of magnetic resonance imaging in animal models, from the smallest species to the animal used most frequently in cardiovascular translational research - the pig. The different contrast media available are discussed, and a systematic guide to the cardiac studies that give the best anatomical and physiological results is presented (AU)

Endogenous cardiac stem cell activation by insulin-like growth factor-1/hepatocyte growth factor intracoronary injection fosters survival and regeneration of the infarcted pig heart.

OBJECTIVES: The purpose of this study was to test the ability of insulin-like growth factor (IGF)-1/hepatocyte growth factor (HGF) to activate resident endogenous porcine cardiac stem/progenitor cells (epCSCs) and to promote myocardial repair through a clinically applicable intracoronary injection protocol in a pig model of myocardial infarction (MI) relevant to human disease. BACKGROUND: In rodents, cardiac stem/progenitor cell (CSC) transplantation as well as in situ activation through intramyocardial injection of specific growth factors has been shown to result in myocardial regeneration after acute myocardial infarction (AMI). METHODS: Acute MI was induced in pigs by a 60-min percutaneous transluminal coronary angiography left anterior descending artery occlusion. The IGF-1 and HGF were co-administered through the infarct-related artery in a single dose (ranging from 0.5 to 2 µg HGF and 2 to 8 µg IGF-1) 30 min after coronary reperfusion. Pigs were sacrificed 21 days later for dose-response relationship evaluation by immunohistopathology or 2 months later for cardiac function evaluation by cardiac magnetic resonance imaging. RESULTS: The IGF-1/HGF activated c-kit positive-CD45 negative epCSCs and increased their myogenic differentiation in vitro. The IGF-1/HGF, in a dose-dependent manner, improved cardiomyocyte survival, and reduced fibrosis and cardiomyocyte reactive hypertrophy. It significantly increased c-kit positive-CD45 negative epCSC number and fostered the generation of new myocardium (myocytes and microvasculature) in infarcted and peri-infarct/border regions at 21 and 60 days after AMI. The IGF-1/HGF reduced infarct size and improved left ventricular function at 2 months after AMI. CONCLUSIONS: In an animal model of AMI relevant to the human disease, intracoronary administration of IGF-1/HGF is a practical and effective strategy to reduce pathological cardiac remodeling, induce myocardial regeneration, and improve ventricular function.

Ventricular arrhythmias and mortality associated with isoflurane and sevoflurane in a porcine model of myocardial infarction.

Ischemia of the myocardium can lead to reversible or irreversible injury depending on the severity and duration of the preceding ischemia. Here we compared sevoflurane and isoflurane with particular reference to their hemodynamic effects and ability to modify the effects of acute severe myocardial ischemia and reperfusion on ventricular arrhythmias and mortality in a porcine model of myocardial infarction. Female Large White pigs were premedicated with ketamine, midazolam, and atropine. Propofol was given intravenously for the anesthetic induction, and anesthesia was maintained with isoflurane or sevoflurane. Endovascular, fluoroscopy-guided, coronary procedures were performed to occlude the midleft anterior descending artery by using a coronary angioplasty balloon. After 75 min, the balloon catheter system was withdrawn and the presence of adequate reperfusion flow was verified. The pigs were followed for 2 mo, and overall mortality rate was calculated. The isoflurane group showed lower arterial pressure throughout the procedure, with the difference reaching statistical significance after induction of myocardial ischemia. The ventricular fibrillation rate was higher in isoflurane group (81.3%) than the sevoflurane group (51.7%; relative risk, 1.57 [1.03 to 2.4]). Overall survival was lower in the isoflurane group (75%) than the sevoflurane group (96.4%). In conclusion, in this porcine model of myocardial ischemia and reperfusion, sevoflurane was associated with higher hemodynamic stability and fewer ventricular arrhythmias and mortality than was isoflurane.

Análisis de la inflamación luminal inducida por distintos tipos de stent coronario en el modelo coronario animal mediante microscopía electrónica de barrido / Scanning electron microscopy analysis of luminal inflammation induced by different types of coronary stent in an animal model

Los stents farmacoactivos se asocian con retraso en la endotelización y fenómenos inflamatorios persistentes demostrados histológicamente. En la superficie luminal, mediante microscopio electrónico de barrido se observan también cúmulos de células inflamatorias. Para cuantificar esta respuesta inflamatoria se implantaron un stent de acero y dos stents farmacoactivos con distintas dosis de vinblastina y el mismo polímero en las coronarias de 12 cerdos domésticos. Se analizó 3 y 7 días después la densidad de células inflamatorias por área representativa (100 x 100 mm). La endotelización del stent de acero fue más completa que en los stents farmacoactivos a los 3 días (p=0,016) y a los 7 días (p=0,0001). Los stents farmacoactivos indujeron un grado de inflamación mayor que los stents de acero a los 3 días (11,8±3.5% frente al 4,5±2%; p=0,001) y a los 7 días (26,3±4,4% frente al 1,2±1,5%; p=0,0001), con un patrón opuesto: la respuesta inflamatoria aumentaba con el tiempo en los stents farmacoactivos, al contrario de lo que sucedía con los stents de acero (AU)

There is histological evidence that drug-eluting stents are associated with delayed endothelialization and a persistent inflammatory state. Moreover, clusters of inflammatory cells have been observed on luminal surfaces by scanning electron microscopy. With the aim of quantifying this inflammatory response, we implanted one bare-metal stent and two drug-eluting stents containing different doses of vinblastine embedded in the same polymer into the coronary arteries of 12 domestic pigs. The density of inflammatory cells in a representative area (100 x 100 mm) was quantified at 3 and 7 days. Endothelialization was more complete in bare-metal stents than in drug-eluting stents at both 3 days (P = .016) and 7 days (P = .0001). The degree of inflammation induced by the drug-eluting stents was higher than that induced by the bare-metal stents at both 3 days (11.8 +/- 3.5% vs. 4.5 +/- 2%; P = .001) and 7 days (26.3 +/- 4.4% vs. 1.2 +/- 1.5%; P = .0001). In addition, the time sequence was inverted: the inflammatory response increased over time with the drug-eluting stents, while the opposite occurred with the bare-metal stents (AU)

Scanning electron microscopy analysis of luminal inflammation induced by different types of coronary stent in an animal model.

There is histological evidence that drug-eluting stents are associated with delayed endothelialization and a persistent inflammatory state. Moreover, clusters of inflammatory cells have been observed on luminal surfaces by scanning electron microscopy. With the aim of quantifying this inflammatory response, we implanted one bare-metal stent and two drug-eluting stents containing different doses of vinblastine embedded in the same polymer into the coronary arteries of 12 domestic pigs. The density of inflammatory cells in a representative area (100 x 100 µm) was quantified at 3 and 7 days. Endothelialization was more complete in bare-metal stents than in drug-eluting stents at both 3 days (P=.016) and 7 days (P=.0001). The degree of inflammation induced by the drug-eluting stents was higher than that induced by the bare-metal stents at both 3 days (11.8±3.5% vs. 4.5±2%; P=.001) and 7 days (26.3±4.4% vs. 1.2±1.5%; P=.0001). In addition, the time sequence was inverted: the inflammatory response increased over time with the drug-eluting stents, while the opposite occurred with the bare-metal stents.