Transfemoral intraluminal graft implantation for abdominal aortic aneurysms.

This study reports on animal experimentation and initial clinical trials exploring the feasibility of exclusion of an abdominal aortic aneurysm by placement of an intraluminal, stent-anchored, Dacron prosthetic graft using retrograde cannulation of the common femoral artery under local or regional anesthesia. Experiments showed that when a balloon-expandable stent was sutured to the partially overlapping ends of a tubular, knitted Dacron graft, friction seals were created which fixed the ends of the graft to the vessel wall. This excludes the aneurysm from circulation and allows normal flow through the graft lumen. Initial treatment in five patients with serious co-morbidities is described. Each patient had an individually tailored balloon diameter and diameter and length of their Dacron graft. Standard stents were used and the diameter of the stent-graft was determined by sonography, computed tomography, and arteriography. In three of them a cephalic stent was used without a distal stent. In two other patients both ends of the Dacron tubular stent were attached to stents using a one-third stent overlap. In these latter two, once the proximal neck of the aneurysm was reached, the sheath was withdrawn and the cephalic balloon inflated with a saline/contrast solution. The catheter was gently removed caudally towards the arterial entry site in the groin to keep tension on the graft, and the second balloon inflated so as to deploy the second stent. Four of the five patients had heparin reversal at the end of the procedure. We are encouraged by this early experience, but believe that further developments and more clinical trials are needed before this technique becomes widely used.

[Structural changes in porcine valvular heterografts preserved in glutaraldehyde]. / Alteraciones estructurales de los heteroinjertos valvulares de porcino preservados en glutaraldehido.

Ultrastructural studies were made of 7 glutaraldehyde-treated porcine valvular heterografts. Five prosthesis had been preserved for a period of 24 months. The remaining two, presented patched areas of different appearance and were eliminated at the routine control studies. Microscopic and electron transmission microscopic observations demonstrated disruption of the endothelial cell layer with preservation of the architecture in the remaining layers. This is consistent with previous works. The other two valves presented lipid degeneration of the spongiosa in one and diffuse fibrous degeneration in the other. This work demonstrates that valves submitted to prolonged storage periods do not undergo further alterations than those recently preserved. It also demonstrates that the pigs own pathology may cause significant structural modifications of the tissue which are only detected with rigorous examination using magnifying optical techniques.

Endoluminal aortic aneurysm repair using a balloon-expandable stent-graft device: a progress report.

We describe our experience with endoluminal repair of abdominal aortic aneurysms using the stent-graft device. Twenty-four patients underwent 25 procedures in the 27-month period ending December 31, 1992. Twenty-one of the patients were considered high-risk candidates for conventional surgical repair. The endoluminal stented grafts were aortoaortic in 16 procedures and unilateral aortoiliac in eight. One patient underwent a second procedure consisting of an ilioiliac graft to repair a separate common iliac artery aneurysm. Technical problems were primarily related to retrograde transluminal access across the iliac arteries, tortuous aneurysms, and misjudgments as to measurement of length. One patient died and another required secondary deployment of a distal stent at 4 months; subsequent aneurysm expansion mandated surgical replacement at 18 months. It is clear that this device and methodology will have to undergo further refinement before the technique is acceptable for wider clinical application. Current experience, however, is encouraging. Aneurysm exclusion with an endoluminal prosthesis is likely to become an important therapeutic alternative over the next several years.

Percutaneous transfemoral insertion of a stented graft to repair a traumatic femoral arteriovenous fistula.

This case report describes a new approach to repair a femoral arteriovenous fistula with a transluminally placed intraarterial graft-covered stent. A balloon-expandable stented polytetrafluoroethylene graft was inserted percutaneously to obliterate an arteriovenous fistula after a bullet injured the left superficial femoral artery and vein of an 18-year-old man. Follow-up duplex ultrasonography at 5 months demonstrated patency and luminal integrity of the involved artery and vein, with resolution of the associated pseudoaneurysm. Additional follow-up will be needed to further substantiate the utility of this minimally invasive procedure in the treatment of traumatic arterial injuries.

Traumatic abdominal aortic pseudoaneurysm treated with balloon-expandable bifurcated endoprosthesis.

A 22-year-old man came to our institution with upper gastrointestinal bleeding and massive intra-abdominal hemorrhage. His history included an abdominal gunshot, with aortic and multiple intestinal perforations, 9 months before. At the time of the original injury, he was treated elsewhere by primary closure of the aortic laceration and multiple intestinal resections. An aortic pseudoaneurysm was revealed by means of an angiogram of the descending aorta. Conventional surgical procedures were deemed not feasible because of previous abdominal operations, so a balloon-expandable bifurcated endoprosthesis was constructed and inserted into the terminal aorta through the femoral approach, with resolution of the abdominal aortic pseudoaneurysm.

Intraluminal bypass of abdominal aortic aneurysm: feasibility study.

This study evaluated the feasibility of treatment of abdominal aortic aneurysm (AAA) by means of intraluminal bypass. Artificial aortic aneurysms with fusiform Dacron conduits were created at surgery , a weft-knit Dacron tube with balloon-expandable stents attached at both ends was inserted transfemorally through a 14-F introducer sheath and expanded at the aneurysmal level by means of inflation of a coaxial balloon. The transluminal bypass successfully excluded the aneurysmal lumen immediately after placement. In two dogs, a postplacement aortogram revealed torsion of the graft that caused early occlusion. The six other dogs had a patent bypass at 6 months follow-up. Four of these dogs had evidence of kinking of the graft as a result of shrinkage of the prosthetic aneurysm. Histopathologic studies revealed that endothelialization was complete on the stents and partial on the graft surface. It is concluded that transluminal bypass of AAA is feasible in the dog model.

Transfemoral endoluminal stented graft repair of a popliteal artery aneurysm.

This report describes the use of an endoluminally placed stented graft to repair a large (2.6 by 2.6 by 15 cm) popliteal aneurysm in a 63-year-old man with advanced heart disease. Two balloon-expandable stents were attached to a 6 mm polytetrafluoroethylene graft, which was inserted with the patient receiving local anesthetic through a proximal superficial femoral artery arteriotomy. Repeat arteriography and duplex ultrasonography performed up to 3 months after the procedure documented graft and distal artery patency and complete aneurysmal exclusion without distal emboli. This experience demonstrates technical feasibility and early graft patency. However, additional experience and follow-up will be needed to assess the value of this minimally invasive procedure in the management of popliteal aneurysmal disease.

Anel portador de válvulas cardíacas / Ring porter of cardiac valves

Apresenta-se um novo tipo de protese, baseada num anel portador de valvulas cardiacas, que, uma vez colocado, permite uma facil colocacao e remocao da valvula, enquanto o anel permanece "in situ". Foi feita a avaliacao do prototipo "in vitro" e foi observada a facilidade para colocar e remover a valvula na camara atrial simulada. Apesar da limitacao na area do orificio, foi testado "in vivo" e o modelo demonstrou que realmente encurta o tempo do "by-pass" cardiopulmonar durante a substituicao da valvula. Nos estudos histopatologicos foi observada uma cura perfeita no meio periprotetico. Um novo desenho esta sendo desenvolvido no laboratorio, a fim de solucionar o problema de superficie efetiva do orificio. Uma vez alcancado este objetivo, este novo conceito devera ser tomado em consideracao em todo futuro projeto de valvulas cardiacas

Protesis valvular cardiaca demontable Desarrollo experimental (Prototipo I) / Dismountable heart valve prosthesis.Experimental development (Prototype I)

Este estudio experimental intenta desarrollar un nuevo tipo de protesis valvular, basado en un anillo portador de las mismas el cual, una vez implantado permitiria o facilitaria la colocacion y remocion de la valvula, mientras el anillo permanece "in situ". El prototipo tiene: a) un anillo portador de valvulas, b) una valvula biologica "ad hoc" y c) un anillo sujetador de la valvula. La evaluacion "in vitro" en una camara atrial simulada ratifico la hipotesis de una facil colocacion y descolocacion valvular, mientras la hidrodinamica permitio deducir una restriccion del area valvular. Entre tanto el problema mencionado es resuelto, la experiencia "in vivo" se presenta como una alternativa viable y valida para la obtencion de datos que podrian satisfacer la expectativa del acortamiento del tiempo quirurgico de la resustitucion valvular

Protesis valvular cardiaca desmontable. Implante experimental "in vivo" y resustitucion valvular alejada. / Dismountable heart valve prosthesis.In vivo experimental implant and delayed valvular replacement

Esta experienca "in vivo" muestra los aspectos tecnicos de la colocacion del anillo portador de valvulas cardiacas Prototipo I, implantado en la posicion tricuspide del corazon de una ternera de 4 meses de edad, bajo circulacion extracorporea estandar; 8 meses despues del implante se procedio a la resustitucion valvular, que insumio 8 minutos, procedimiento que fue facilitado por el anillo portador que permanecio "in situ". No se observo fenomeno trombotico ni solucion de continuidad periprotesica. Histopatologicamente se encontro un neoendotelio y tejido subyacente menor a 1 mm de espesor, y una adecuada cicatrizacion perianular. Estos hallazgos impulsan la investigacion de un diseno que resuelva la disminucion del area valvular de este modelo

Protesis valvular cardiaca demontable Desarrollo experimental (Prototipo I) / Dismountable heart valve prosthesis.Experimental development (Prototype I)

Este estudio experimental intenta desarrollar un nuevo tipo de protesis valvular, basado en un anillo portador de las mismas el cual, una vez implantado permitiria o facilitaria la colocacion y remocion de la valvula, mientras el anillo permanece "in situ". El prototipo tiene: a) un anillo portador de valvulas, b) una valvula biologica "ad hoc" y c) un anillo sujetador de la valvula. La evaluacion "in vitro" en una camara atrial simulada ratifico la hipotesis de una facil colocacion y descolocacion valvular, mientras la hidrodinamica permitio deducir una restriccion del area valvular. Entre tanto el problema mencionado es resuelto, la experiencia "in vivo" se presenta como una alternativa viable y valida para la obtencion de datos que podrian satisfacer la expectativa del acortamiento del tiempo quirurgico de la resustitucion valvular

Protesis valvular cardiaca desmontable. Implante experimental "in vivo" y resustitucion valvular alejada. / Dismountable heart valve prosthesis.In vivo experimental implant and delayed valvular replacement

Esta experienca "in vivo" muestra los aspectos tecnicos de la colocacion del anillo portador de valvulas cardiacas Prototipo I, implantado en la posicion tricuspide del corazon de una ternera de 4 meses de edad, bajo circulacion extracorporea estandar; 8 meses despues del implante se procedio a la resustitucion valvular, que insumio 8 minutos, procedimiento que fue facilitado por el anillo portador que permanecio "in situ". No se observo fenomeno trombotico ni solucion de continuidad periprotesica. Histopatologicamente se encontro un neoendotelio y tejido subyacente menor a 1 mm de espesor, y una adecuada cicatrizacion perianular. Estos hallazgos impulsan la investigacion de un diseno que resuelva la disminucion del area valvular de este modelo