Structural improvement and analysis of a novel endoscopic succession closing device / 医用生物力学

Objective By developing a novel endoscopic succession closing device to overcome the shortcomings of existing devices that cannot deploy several clips at one time,to perform structural analysis on different clamp structures and to validate their performances in tissue closure through finite element analysis.Metbods Comparative analyses of 3 clamp structures,namely,the aligning tooth structure (original,clamp A),the staggered tooth structure (clamp B),a combination structure with page break angle and staggered tooth (clamp C),were performed to analyze pressure and its distribution on tissues when clamping the stomach wall.Displacement of 7.5 mm was then applied on the clamps to simulate the effect from operating procedures of the device and tissue kick-back.Results The maximum stresses of the clamp A and B were located on the first pair of teeth which was closest to the rotating shaft,with the stress of 10.39 kPa and 10.11 kPa,respectively.The maximum stress (11.35 kPa) of the clamp C was located on the second pair of teeth.For clamp A and B,the longer the distance to shaft,the larger pressure on stomach tissues.While for clamp C,the pressure on device-tissue interface showed little change along the path.Under tensile displacement,clamp A and B slipped off from the tissue when displacements reached to 5.0 mm and 6.5 mm,respectively,while clamp C did not slip off.Conclusions Clamp with page break angle and staggered tooth can exert the uniform maximum pressure to tissues and provide a larger contact area away from the rotating shaft,thus improving the anti-slippage and performance of the novel endoscopic closing device.

Structural improvement and analysis of a novel endoscopic succession closing device / 医用生物力学

By developing a novel endoscopic succession closing device to overcome the shortcomings of existing devices that cannot deploy several clips at a time, to perform structural analysis on different clamp structures and to validate their performances in tissue closure through finite element analysis. Methods Comparative analyses of three clamp structures, namely, the aligning tooth structure (original, clamp A), the staggered tooth structure (clamp B), a combination structure with page break angle and staggered tooth (clamp C), were performed to analyze pressure and its distribution on tissues when clamping the stomach wall. Displacement of 7.5 mm was then applied on the clamps to simulate the effect of the operating procedures of the device and tissue kick-back. Results The maximum stresses of the clamp A and B were located on the first pair of teeth which was closest to the rotating shaft, with the stress being 10.39 kPa and 10.11 kPa, respectively. The maximum stress (11.35 kPa) of the clamp C was located on the second pair of teeth. For clamp A and B, the longer the distance to shaft, the larger pressure on stomach tissues. While for clamp C, the pressure on device-tissue interface showed little change along the path. Under tensile displacement, clamp A and B slipped off from the tissue when displacements reached to 5 mm and 6.5 mm, respectively, while clamp C did not. Conclusions　Clamp with page break angle and staggered tooth can exert the uniform max pressure to tissues and provide a larger contact area away from the rotating shaft, thus improving anti-slippage and performance of the novel endoscopic closing device.

Structural improvement and analysis of a novel endoscopic succession closing device / 医用生物力学

Objective By developing a novel endoscopic succession closing device to overcome the shortcomings of existing devices that cannot deploy several clips at one time,to perform structural analysis on different clamp structures and to validate their performances in tissue closure through finite element analysis.Metbods Comparative analyses of 3 clamp structures,namely,the aligning tooth structure (original,clamp A),the staggered tooth structure (clamp B),a combination structure with page break angle and staggered tooth (clamp C),were performed to analyze pressure and its distribution on tissues when clamping the stomach wall.Displacement of 7.5 mm was then applied on the clamps to simulate the effect from operating procedures of the device and tissue kick-back.Results The maximum stresses of the clamp A and B were located on the first pair of teeth which was closest to the rotating shaft,with the stress of 10.39 kPa and 10.11 kPa,respectively.The maximum stress (11.35 kPa) of the clamp C was located on the second pair of teeth.For clamp A and B,the longer the distance to shaft,the larger pressure on stomach tissues.While for clamp C,the pressure on device-tissue interface showed little change along the path.Under tensile displacement,clamp A and B slipped off from the tissue when displacements reached to 5.0 mm and 6.5 mm,respectively,while clamp C did not slip off.Conclusions Clamp with page break angle and staggered tooth can exert the uniform maximum pressure to tissues and provide a larger contact area away from the rotating shaft,thus improving the anti-slippage and performance of the novel endoscopic closing device.

Structural improvement and analysis of a novel endoscopic succession closing device / 医用生物力学

Objective By developing a novel endoscopic succession closing device to overcome the shortcomings of existing devices that cannot deploy several clips at one time,to perform structural analysis on different clamp structures and to validate their performances in tissue closure through finite element analysis.Metbods Comparative analyses of 3 clamp structures,namely,the aligning tooth structure (original,clamp A),the staggered tooth structure (clamp B),a combination structure with page break angle and staggered tooth (clamp C),were performed to analyze pressure and its distribution on tissues when clamping the stomach wall.Displacement of 7.5 mm was then applied on the clamps to simulate the effect from operating procedures of the device and tissue kick-back.Results The maximum stresses of the clamp A and B were located on the first pair of teeth which was closest to the rotating shaft,with the stress of 10.39 kPa and 10.11 kPa,respectively.The maximum stress (11.35 kPa) of the clamp C was located on the second pair of teeth.For clamp A and B,the longer the distance to shaft,the larger pressure on stomach tissues.While for clamp C,the pressure on device-tissue interface showed little change along the path.Under tensile displacement,clamp A and B slipped off from the tissue when displacements reached to 5.0 mm and 6.5 mm,respectively,while clamp C did not slip off.Conclusions Clamp with page break angle and staggered tooth can exert the uniform maximum pressure to tissues and provide a larger contact area away from the rotating shaft,thus improving the anti-slippage and performance of the novel endoscopic closing device.

Erosión muy tardía de la aurícula derecha con dispositivo Amplatzer®; reporte de un caso / Very late erosion of the right atrium with Amplatzer® device

Resumen La erosión tardía de la pared auricular y de la aorta es una causa infrecuente, pero potencialmente mortal en los pacientes que han sido sometidos al cierre percutáneo de un defecto del septum auricular, en especial cuando existe una alta relación entre el tamaño del dispositivo escogido con el tamaño del defecto y la presencia de bordes insuficientes. Presentamos el caso de un hombre de 70 años con un episodio de colapso hemodinámico secundario a taponamiento cardiaco debido a erosión muy tardía de la aurícula derecha por un Amplatzer® implantado 4 años atrás para el cierre de un defecto septal auricular. Conclusión La erosión tardía de los dispositivos de cierre percutáneo para los defectos atriales, aunque infrecuente, deberá ser tenida en cuenta en los pacientes que presentan colapso hemodinámico.

Abstract Late atrial wall and aorta erosion is a rare cause of potential fatallity in patients who have undergone percutaneous closure of an atrial septal defect, especially when a high ratio device to defect is chosen, and an insufficient aortic rim is present. We report the case of a 70 year old male with an episode of hemodinamic collapse secondary to cardiac tamponade due to a late erosion of a 4 years ago implanted Amplatzer® used to close an atrial septal defect. Conclusion Very late wall erosion of an atrial septal closure device, although uncommon, should be suspected in patients presenting with hemodynamic collapse.

Design and analysis of a novel endoscopic successive hemostasis and closing device / 医用生物力学

Objective To design a novel endoscopic successive hemostasis and closing device, and to validate whether the device can meet the needs of tissue closure by finite element analysis. Methods By using the novel device, the target tissue was clamped and the clip was then pushed to pierce the tissue. Under the compression between the clip and the inner side of the grasper, the thinner arms of the clip were forced to bend and close to stay in the tissue, and then the inverse displacement of 2 mm was applied on the clip. The elastic limit and tensile strength of the clip were set as 239.0 and 901.0 MPa, respectively. Results Deformation did not occur in the piercing process of the clip, with the maximum stress of 212.6 MPa. The deformed shape of the clip in the bending process matched its design expectation, with the maximum stress of 727.7 MPa. The maximum stress of the clip was 75.8 MPa under 2-mm inverse displacement. Material failure was not found in the bending process or with 2-mm inverse displacement, and the maximum stress in the whole process was 741.0 MPa. Conclusions The novel endoscopic successive hemostasis and closing device proposed in this study can deploy 4 clips at one time, together with an independent grasper for gathering tissues, which can shorten the reloading time and improve the accuracy of clip deployment. The effectiveness and safety of the device is also proved by using finite element method.

Uso de ecocardiografía intracardiaca para cierre percutáneo de foramen ovale permeable / Use of intracardiac echocardiography for percutaneous closure of patent foramen ovale

Objetivo: determinar la utilidad del ecocardiograma intracardiaco como ayuda para la implantación de dispositivo de cierre percutáneo de foramen ovale permeable. Material y métodos: se expone el caso de un paciente de género masculino, de 38 años de edad, con antecedentes de isquemia cerebral transitoria, diagnosticada un año antes, quien presentó cuadro de accidente cerebrovascular isquémico criptogénico y se le detectó foramen ovale permeable por ecocardiograma transesofágico. Se candidatizó para cierre percutáneo con dispositivo de cierre tipo Amplatzer, y se programó el procedimiento con ecocardiograma intracardiaco mediante sonda AcuNav para guiar la colocación del Amplatzer, junto con el ecocardiograma transesofágico tradicional requerido en estos casos. Resultados: se realizó cierre del foramen ovale permeable mediante la técnica aceptada, guiado por ecocardiografía intracardiaca y se verificó mediante angiografía y ecocardiograma transesofágico. Se obtuvieron imágenes de la anatomía cardiaca mediante ecocardiograma intracardiaco en tiempo real sin interferencia, con lo cual pudo hacerse el implante del dispositivo en forma rápida y adecuada. Se corroboró su correcta implantación a través de angiografía y ecocardiograma transesofágico. En este caso, el procedimiento de cierre percutáneo con dispositivo de Amplatzer fue exitoso, rápido y sin complicaciones. Conclusiones: el ecocardiograma intracardiaco es útil para guiar la implantación de dispositivos de cierre del foramen ovale permeable así como en casos de comunicación interauricular. Es una técnica fácil y segura. La introducción de la sonda de ecocardiograma intracardiaco, su manipulación y su posicionamiento en el atrio derecho fueron rápidos y sencillos. Se obtuvieron imágenes adecuadas con una buena identificación de las estructuras del septum que permitieron el cierre exitoso del foramen ovale permeable con dispositivo tipo Amplatzer. Según esta investigación, en la literatura no se reporta el ecocardiograma intracardiaco como ayuda para guiar este procedimiento, por lo que se considera que pudiera ser el primer caso realizado en Colombia. De otra parte, se hace necesario el uso más generalizado de la sonda intracardiaca para realizar ecocardiograma intracavitario e implementarlo en lugar del ecocardiograma transesofágico como guía para cierre de comunicación interauricular y foramen ovale permeable. Es conveniente llevar a cabo más estudios que permitan valorar mejor esta ayuda que puede suprimir la necesidad del ecocardiograma transesofágico en estos pacientes y a su vez el requerimiento de anestesia general para estos procedimientos.

Objective: to determine the utility of intracardiac echocardiography to assist in the implantation of the device for percutaneous closure of patent foramen ovale. Material and methods: we report the case of a 38 years old male patient with a history of transient cerebral ischemia diagnosed a year earlier, who presented a clinical picture of ischemic cryptogenic stroke. A transesophageal echocardiogram showed a patent foramen ovale. He was scheduled for percutaneous closure of the patent foramen ovale with Amplatzer closure device, and the procedure was programmed with intracardiac echocardiography probe through AcuNav to guide the placement of the Amplatzer, along with the traditional TEE required in these cases. Results: we performed foramen ovale closure using the accepted technique, guided by intracardiac echocardiography and verified by angiography and transesophageal echocardiography. We obtained images of cardiac anatomy using intracardiac echocardiography in real time without interference, which made possible the implant of the device quickly and appropriately. Proper implementation was confirmed by angiography and transesophageal echocardiography. In this case, the procedure of percutaneous closure with Amplatzer device was successful, fast and without complications. Conclusions: intracardiac echocardiography is useful to guide the implantation of devices for closure of patent foramen ovale as well as in cases of atrial septal defect. This technique is easy and safe. The introduction of intracardiac echocardiography catheter, its handling and positioning in the right atrium were quick and easy. Adequate images were obtained with a good identification of the structures of the septum that allowed the successful closure of the foramen ovale with Amplatzer device. According to this research, the literature does not report intracardiac echocardiography as an assistance to guide this procedure, so that we believe this may be the first case performed in Colombia. Moreover, it is necessary a more widespread use of intracardiac catheter for intracavitary echocardiography and implement it instead of transesophageal echocardiography as guide for closure of atrial septal defect and patent foramen ovale. It is convenient to carry out more studies to better assess this assistance which may eliminate the need of transesophageal echocardiography in these patients and in turn the requirement of general anesthesia for these procedures.

Three strategies for hemostasis at femoral artery access site: a comparison of safety and efficacy / 第二军医大学学报

Objective:To assess the safety and efficacy of the standard manual compression and 2 arterial puncture closing devices,Angioseal and Perclose,for hemostasis at the femoral artery access site in patients undergoing coronary angiography(CAG) or percutaneous coronary interventions(PCI).Methods: Totally 366 patients undergoing coronary angiography or PCI were assigned to receive either Angioseal(n=128),Perclose(n=110) or standard manual compression(n=128).The efficacy endpoint(immediate hemostasis,successful hemostasis rate,operating time,time of leg immobilization and time to hemostasis) and safety endpoint(vasovagal reflex,major complications,local complications,hematocrit drop,etc.) were evaluated.Risk factors(gender,age,body mass index,comorbid conditions,antiplatelet agents,and anticoagulant agents,etc.) were also analyzed.Results: The successful hemostasis rates were similar between Angioseal group and Perclose group,but the rate of immediate hemostasis of Angioseal group was higher than that of Perclose group(P