TC multicorte (TCMC) cardiaca: aplicaciones clínicas / Multislice CT of the heart: clinical applications

La introducción de los equipos de TC multicorte y el desarrollo de técnicas de adquisición de imágenes con sincronización electrocardiográfica y reconstrucción retrospectiva han permitido que la TC multicorte cardiaca se pueda considerar hoy en día una técnica no invasiva muy útil para el estudio de la patología cardiaca en la práctica clínica diaria. La valoración de las arterias coronarias es una de las principales aplicaciones clínicas de esta técnica diagnóstica e incluye la detección y cuantificación del calcio coronario, la coronariografía por TC multicorte (estudio de la anatomía coronaria, variantes anatómicas y anomalías del origen y trayecto), la valoración angiográfica de la permeabilidad de injertos aortocoronarios y endoprótesis vasculares y la caracterización de las placas de ateroma. Los nuevos programas de reconstrucción y postprocesamiento permiten obtener, además, parámetros de morfología y contracción miocárdica y función cardiaca. Otras aplicaciones clínicas incluyen la caracterización de masas cardiacas intracavitarias y la valoración del pericardio (AU)

Injertos suprageniculares con politetrafluoroetileno. Factores que pueden influir en su permeabilidad / Above knee polytetrafluoroethylene grafts. Factors that may influence patency

Objetivo. Identificar posibles factores relacionados con la oclusión de los injertos suprageniculares de politetrafluoroetileno (PTFE). Pacientes y métodos. Estudio de 100 injertos femoropoplíteos suprageniculares de PTFE realizados en 98 pacientes (77 varones y 21 mujeres, con una edad media de 69 años; intervalo: 49-90 años). En 90 casos se indicó la revascularización por isquemia crítica de laextremidad y en 10 por claudicación intermitente. Estudio observacional retrospectivo durante un período de cinco años. Se evaluaron los parámetros siguientes: edad (mayor o menor de 65 años), sexo, factores de riesgo cardiovasculares, índice tobillo/brazo, salida distal, fibrinógeno (superior o inferior a la media de 5,7 g/ L) y celularidad sanguínea: hematocrito >45 per cent, leucocitos >10.000 y plaquetas >250.000. Para el análisis estadístico se utilizó la regresión multivariante de Cox y tablas devida Kaplan-Meier. Resultados. La permeabilidad a los 30 días fue del 99 per cent, y la acumulativa a 1, 2 y 5 años fue del 75, 56 y 41 per cent, respectivamente. El 75 per cent de las oclusiones se produjeron en los primeros 18 meses (permeabilidad del 67 per cent). En este período de 18 meses el único factor predictivo de oclusión de los injertos fue el fibrinógeno y la celularidad sanguínea (p< 0,05). A los cinco años los factores predictivos de oclusión fueron la salida distal (p= 0,01), fibrinógeno (p= 0,001) y celularidad sanguínea (p= 0,001). La permeabilidad secundaria fue del 41 per cent y el salvamento de extremidad del 82 per cent a los cinco años. Conclusión. Cifras altas de fibrinógeno y celularidad sanguínea influyen negativamente en la permeabilidad de los injertos suprageniculares de PTFE (AU)

Utilidad de las fístulas arteriovenosas autólogas para hemodiálisis en pacientes diabéticos / Value of autologous arteriovenous fistulae for haemodialysis in diabetic patients

Objetivo. Evaluar la permeabilidad de las fístulas arteriovenosas (FAV) para hemodiálisis realizadas en nuestro servicio, con la comparación de los resultados en pacientes diabéticos y no diabéticos. Pacientes y métodos. Análisis retrospectivo de 273 FAV autólogas realizadas en 222 pacientes, durante tres años (1998-2000). De estos 222 pacientes, 73 (32,9 per cent) eran diabéticos, y 149 (67,1 per cent), no diabéticos. Se realizaron un total de 138 FAV radiocefálicas (50,5 per cent) -48 en diabéticos y 90 en no diabéticos- y 135 FAV humerocefálicas (49,5 per cent) -43 en diabéticos y 92 en no diabéticos-. Al 20,3 per cent de los pacientes se les realizó más de una FAV. Se aplicó análisis estadístico univariante y multivariante mediante regresión de Cox y cálculo de probabilidad por Kaplan-Meier. Resultados. El seguimiento medio fue de 12 meses (intervalo, 136). La permeabilidad global primaria al año y a los dos años fue de 65 y 58 per cent, respectivamente. Los pacientes diabéticos tienen una permeabilidad al año y a los dos años del 60 y 40 per cent, respectivamente, frente a un 73 y 62 per cent, respectivamente, de los no diabéticos, pero en el seguimiento tardío los diabéticos tienen una mayor probabilidad de trombosis frente a los no diabéticos -odds-ratio, 1,49 (0,97-2,3)-. No hubo diferencias de permeabilidad al año entre FAV radiocefálicas y humerocefálicas. Ninguno de los factores analizados tuvo significación estadística en la permeabilidad. Conclusiones. La diabetes actúa de factor de riesgo en la permeabilidad de las fístulas a largo plazo. No hay diferencias estadísticamente significativas según el lugar de realización de las FAV (AU)

Caracterización y biocompatibilidad de las prótesis vasculares de poliuretano estabilizado con polidimetilsiloxano / Characterization and biocompatibility of vascular prostheses made of polyurethane stabilized with polydimethylsiloxane

Introducción. El desarrollo de nuevos biomateriales ha desembocado en la aparición de nuevas prótesis vasculares que mejoren el comportamiento de injertos protésicos de pequeño calibre. Objetivo. El objetivo del presente trabajo es el estudio del comportamiento biológico de prótesis vasculares de poliuretano. Material y métodos. Prótesis: poliuretano-polidimetilsiloxano (PU-PDMS). Caracterización: fragmentos de PU-PDMS se procesaron para su estudio en microscopia óptica y electrónica de barrido. Se determinó la carga eléctrica de la superficie interna mediante análisis espectral. Biocompatibilidad: fragmentos (1 cm2) de PU-PDMS se implantaron en el músculo dorsal de conejos Nueva Zelanda (n= 18) durante 3 y 8 meses. Realizamos estudios morfológicos, inmunohistoquímicos (antiactina) y de reacción de cuerpo extraño (RAM11). Siembra: fragmentos de 1 cm2 se sembraron con células endoteliales de vena umbilical humana. Tiempos de estudio: 24, 48, 72 horas y 7 días. Resultados. La composición es fibrilar, con presencia de numerosos poros. Existencia de cargas negativas en la superficie interna del biomaterial. A los tres meses, la prótesis se embebe en tejido neoformado muy vascularizado y rico en células blancas y células de reacción a cuerpo extraño. A los 8 meses se puede observar la total integración del biomaterial, que aparece rodeado de colágeno y muy vascularizado. A las 24 horas de la siembra observamos una superficie endotelizada, que deja al descubierto grandes poros que se tapizan en los estadios posteriores. Conclusiones. Las prótesis PUPDMS presentan características adecuadas para utilizarse como sustitutos vasculares, gracias a su estructura, ausencia de rechazo y buena integración a corto y medio plazo. (AU)

Prótesis wallstent en estenosis y oclusiones venosas centrales en pacientes de hemodiálisis / The Wallstent endoprosthesis in hemodialysis patients presenting central venous stenosis or occlusion

Objetivo: Describir la efectividad y complicaciones a medio plazo de la prótesis Wallstent en el tratamiento de estenosis y oclusiones venosas centrales en los pacientes de hemodiálisis.Material y Métodos: Se presentan nueve pacientes en hemodiálisis (cuatro varones y cinco mujeres) con una edad media de 64 años que presentaron estenosis (seis pacientes) o trombosis (tres pacientes) en venas centrales (vena subclavia: cuatro; tronco venoso innominado: cuatro y ambos sectores: uno). Todos los pacientes habían sido antiguos portadores de catéteres yúgulo-subclavios para hemodiálisis en el lado afectado.Las indicaciones para la implantación de la prótesis Wallstent fueron por estenosis elástica postangioplastia inmediata (tres pacientes), reestenosis antes de seis meses postangioplastia (tres pacientes) e indicación primaria de la prótesis por oclusión venosa (tres pacientes).Las prótesis empleadas fueron de 10-16 mm de diámetro y todos los pacientes permanecieron anticoagulados y antiagregados tras la implantación de la misma.Resultados: Un paciente presentó una migración proximal a la vena cava superior a las 48 horas de implantada la prótesis. Otro paciente sufrió un oclusión de la prótesis a las 24 horas que se trató con la implantación coaxial de una nueva.A todos los pacientes se les realizó un seguimiento flebográfico del brazo observándose en cinco de ellos una estenosis dentro de la prótesis y en otros dos una oclusión de la misma tras un tiempo medio de seis meses (2-15 meses) y se trataron mediante angioplastia (cuatro pacientes) o nueva prótesis coaxial (tres pacientes).Tras nueve reintervenciones y un período medio de seguimiento de 16 meses (0-36 meses) hemos obtenido una 'permeabilidad asistida' del 67 por ciento.Conclusión: Aunque la implantación de Wallstents para tratar estenosis y oclusiones venosas centrales es un buen procedimiento que permite prolongar el acceso vascular para la hemodiálisis, no está exento de riesgos y son muy frecuentes las reintervenciones por reestenosis para mantenerla permeable (AU)

Abdominal aortic tailoring for renal, visceral, and lower extremity malperfusion resulting from acute aortic dissection.

PURPOSE: The treatment of ischemic complications that result from aortic dissection is a challenging and controversial problem. The purpose of this study was to evaluate aortic tailoring in the management of acute aortic dissection associated with visceral, renal, or lower extremity ischemia. METHODS: We retrospectively reviewed the clinical courses of seven consecutive patients (five men, two women) with a median age of 68 years (range, 48 to 74 years) from January 1994 to January 1997. All patients underwent an abdominal aortic tailoring procedure for relief of ischemic complications associated with acute aortic dissection (type IIIB, n = 6; type I, n = 1) and a normal-sized aorta. RESULTS: All seven patients survived and recovered full mesenteric, renal, and lower extremity function. Two patients required temporary hemodialysis in the immediate postoperative period. There has been no significant dilatation of the tailored aortic segments, with an average follow-up of 19 months (range, 1 to 30 months). CONCLUSIONS: Abdominal aortic tailoring represents a safe and effective method for treating ischemic complications associated with acute aortic dissection and a normal aortic luminal diameter.

Supraceliac aortorenal bypass.

PURPOSE: To determine the efficacy and durability of supraceliac aortorenal bypass grafting for symptomatic atherosclerotic renal artery disease. METHODS: Retrospective review of a 10-year, single-institution experience. RESULTS: Seventeen patients underwent 27 bypass procedures (seven unilateral, 10 bilateral) for atherosclerotic renovascular hypertension. The patients' mean age was 62.7 +/- 8.8 years. Diffuse aortoiliac and visceral atherosclerosis was confirmed on arteriogram; most (88%) celiac axis branches and all infrarenal aortas and common iliac arteries were found unsuitable for use as a donor vessel. Twenty-six bypass procedures (96%) were performed with autologous vein grafts. Seventeen bypass procedures (63%) were performed during partial aortic occlusion. There were no operative deaths or early occlusions. Postoperative complications occurred in four patients (24%). The mean duration of follow-up was 28 +/- 19 months (range, 2 to 69 months). By life table analysis, the 5-year primary patency and assisted primary patency rates were 95% and 100%, respectively. The mean systolic blood pressure decreased from 180 +/- 38 mm Hg to 135 +/- 20 mm Hg (p = 0.0003), and the mean diastolic blood pressure decreased from 96 +/- 16 mm Hg to 77 +/- 9 mm Hg (p = 0.0002). The number of antihypertensive medications decreased from 2.8 +/- 1.2 to 1.4 +/- 1.0 (p = 0.002). Significant improvement in serum creatinine level was seen among patients with preoperative renal insufficiency. Hypertension was cured in 29%, improved in 53%, and unchanged in 18%. During late follow-up, only four patients (24%) required subsequent aortic reconstruction. CONCLUSION: Supraceliac aortorenal bypass grafting is a safe and durable alternative for renal artery revascularization. This technique should be considered in patients who have diffuse infrarenal aortoiliac and visceral artery occlusive disease and require renal revascularization procedures.

Technical complications of endovascular abdominal aortic aneurysm repair.

PURPOSE: Results from 34 endovascular repairs of abdominal aortic aneurysms are reviewed to identify technical complications and relate them to anatomic and technical features of the operation. METHODS: Twenty-one patients underwent attempted tube graft repair (mean follow-up, 13 months). Thirteen patients underwent placement of a bifurcated graft (mean follow-up, 7.2 months). RESULTS: Twenty-five patients (74%) underwent repair without technical complication (16 tube graft and nine bifurcated graft). Of five patients who had tube graft complications, two involved small iliac arteries and resulted in arterial injury. One of these patients needed a femorofemoral bypass procedure, and the other required conversion to standard operation. Two patients had distal leaks associated with the attachment system, and one patient had misplacement of the distal attachment system. The two patients who had leaks were followed-up; one required operation after 7 months, whereas the other leak sealed. The patient who had distal attachment system misplacement had a second endograft placed within the first to provide a distal seal. The four patients who had bifurcated graft complications involved two graft limb stenoses, one managed with a Palmaz stent and the other with balloon angioplasty. The patient treated with balloon angioplasty had graft thrombosis 1 week after the operation, which resulted in the need for a femorofemoral bypass procedure. Another bifurcated graft patient had a graft limb twist, which has resulted in chronic claudication. One patient had placement of a limb too proximal in the common iliac artery with chronic leak, and an open operation was performed 18 months later. CONCLUSIONS: Technical complications in this series seem to be associated with short distal necks, small iliac arteries, tortuous iliac arteries, and atherosclerosis at the aortic bifurcation. We believe that experience and understanding of these issues will reduce the risk of these complications in the future.

Endovascular treatment of infrarenal abdominal aneurysms by the Stentor system: preliminary results of 79 cases. Stentor Retrospective Study Group.

PURPOSE: We report the initial French multicenter experience with the Stentor system in the endovascular treatment of AAAs. METHODS: Between May 1994 and March 1996, 79 patients with AAAs were consecutively treated with an endovascular technique using the Stentor system. There were 71 bifurcated grafts and eight straight grafts. The patients were followed-up from 1 to 18 months (mean, 5.7 months). Patient data and events were retrospectively analyzed. RESULTS: No patients was lost to follow-up. There were no surgical conversions. Four patients died after operation (4.8%). Two of them had been considered inoperable by the standard technique. Four patients (4.8%) had pulmonary complications, and three had colonic ischemia (3.7%). Forty-five patients (57%) had postoperative fever, and a transitory thrombocytopenia (10%) developed in eight patients. In 66 patients (83%) the aneurysm was immediately excluded. The exclusion was definitive in 62 (78%). In 17 patients, there were 13 initial and six delayed endoleaks. In two of these patients, the initial endoleak sealed temporarily and resumed after 1 year of follow-up, requiring an additional straight, covered stent. Over all, seven of the leaks were treated successfully by an additional endovascular graft, one leak required a lumbar artery embolization, eight leaks sealed spontaneously, and one leak was untreated. During follow-up, there was no aneurysm rupture. Two patients died of unrelated causes. CONCLUSION: The Stentor system can safely and effectively exclude AAAs in the short term. Careful follow-up is required to detect any delayed endoleak, and long-term results are awaited to confirm the efficacy of the method in preventing AAA rupture.

Endovascular grafts for noninfected aortoiliac anastomotic aneurysms.

PURPOSE: This report describes our experience with endovascular repair of aortic and iliac anastomotic aneurysms. METHODS: Between June 1994 and March 1996, 12 noninfected aortic or iliac anastomotic aneurysms in 10 patients who had serious comorbid medical conditions that precluded or made difficult standard operative repair were treated using endovascular grafts. No patient in this study had a history of fever, leukocytosis, or computed tomographic evidence of a periprosthetic fluid collection that was suggestive of infection of the original graft. Endovascular grafts composed of polytetrafluoroethylene and balloon-expandable stents were introduced through a femoral arteriotomy and were placed using over-the-wire techniques under C-arm fluoroscopic guidance. RESULTS: Endovascular grafts were successfully inserted in all patients with aortic or iliac anastomotic aneurysms. There were no procedure-related deaths, and complications included one postprocedure wound hematoma and one perioperative myocardial infarction. Graft patency has been maintained for a mean of 16.1 months, with no computed tomographic evidence of aneurysmal enlargement or perigraft leakage. CONCLUSIONS: Endovascular grafts appear to be a safe and effective technique for excluding some noninfected aortoiliac anastomotic aneurysms in high-risk patients and may become a treatment option in all patients who have clinically significant lesions.

Chronic intraaneurysmal pressure measurement: an experimental method for evaluating the effectiveness of endovascular aortic aneurysm exclusion.

PURPOSE: To evaluate and compare the intraaneurysmal pressure (IAP) after exclusion using two different endovascular grafts. METHODS: Eight mongrel dogs had a 3 x 3 cm polytetrafluoroethylene (PTFE) aneurysm sewn as an interposition graft of the infrarenal aorta. A pressure transducer implanted into the aneurysm wall permitted continuous electronic IAP monitoring. Four aneurysms were excluded with a transluminally placed endovascular graft made of a PTFE graft and two Palmaz stents (PTFE-EG), three were excluded with a tantalum-Dacron endovascular graft (TD-EG), and one was surgically treated with a standard PTFE graft (PTFE-Surg). The dogs were observed for 18 to 50 days (mean, 37.5 days) and were evaluated after surgery with duplex and spiral computed tomographic scans. RESULTS: All grafts successfully excluded the aneurysms without perigraft channels or leaks as documented by arteriogram and duplex and computed tomographic scans. The mean IAPs after repair with all PTFE-EGs were significantly lower (p < 0.001) than the mean systemic pressures. In addition, the mean IAP reduction was significantly greater (p < 0.005) in the PTFE-EG group than in the TD-EG group. CONCLUSIONS: Aneurysm exclusion with PTFE-EG significantly lowered IAP, did so significantly better than the TD-EG, and approached the IAP reduction obtained by standard repair. Such pressure reduction is necessary for effective protection against aneurysm rupture.

New-generation valved conduit: an experimental study.

OBJECTIVE: An ideal valved conduit to repair complex congenital heart defects is yet to be developed. In this study we have evaluated the merits of our newly developed calcification-free biologic valve incorporated in a compatible conduit of biologic origin in an animal model. METHODS: Porcine aortic valves and main pulmonary arteries were cross-linked in glutaraldehyde, followed by coupling to partially degraded heparin through an intermediate surface-bound substrate containing amino groups. Because commercially available valves are treated only with glutaraldehyde, control aortic valves and main pulmonary arteries were cross-linked in 0.625% glutaraldehyde. Valved conduits were fabricated from main pulmonary arteries, which were sewn to the aortic and ventricular ends of aortic valves. Valved conduits were examined for calcification and other pathologic changes after being implanted in the descending thoracic aorta in juvenile sheep for 5 months. RESULTS: Severe calcification was noticed in all layers of cusps (calcium, 231.86 +/- 17.90 mg/gm) and aortic wall (calcium, 123.24 +/- 24.72 mg/gm) of aortic valves and main pulmonary arteries (calcium, 135.43 +/- 26.63 mg/gm) of valved conduits treated with 0.625% glutaraldehyde. Cusps (calcium, 1.28 +/- 0.22 mg/gm) of the aortic valve of heparin-bonded conduits did not calcify at all. Only sparse calcific deposits were noticed in the medial layer of the aortic wall (calcium, 25.90 +/- 22.79 mg/gm) of aortic valves and main pulmonary arteries (calcium, 9.64 +/- 10.79 mg/gm) of the valved conduits coupled to heparin. CONCLUSION: Heparin coupling is effective in preventing calcification of glutaraldehyde cross-linked valved conduits implanted in the systemic circulation of juvenile sheep.

Is color duplex surveillance of infrainguinal polytetrafluoroethylene grafts worthwhile?

BACKGROUND: Unlike vein bypasses, the role of duplex surveillance of infrainguinal prosthetic bypass grafts is controversial. The purpose of this study was to evaluate the adequacy of color duplex surveillance in identifying failing infrainguinal polytetrafluoroethylene (PTFE) bypass grafts and to assess its value in predicting continued bypass patency. METHOD: The surveillance data of primarily patent PTFE bypass grafts were compared with those of revised/occluded PTFE grafts. Ninety-five patients underwent 102 infrainguinal PTFE bypass grafts from January 1991 to December 1996 and were enrolled in a duplex surveillance program at 1 month postoperatively, every 3 months in the first year, every 6 months in the second year, and yearly thereafter. RESULTS: Seventy grafts remained primarily patent, 5 were revised and 27 occluded. There was no significant difference in the mean age, gender, indication for surgery, type of original procedure, or duration of follow-up between both groups. Four hundred and seven duplex surveillance data were available for analysis. Focal increase in peak systolic velocity (PSV) 3 x the adjacent segment or low flow manifested by PSV <45 cm/sec were considered abnormal. In the primarily patent group, 5 bypasses had abnormal duplex surveillance and were found to have no abnormality on angiogram and remained patent during the study period. In the revised/occluded group, duplex surveillance was abnormal in 8 bypasses. Twenty-four bypasses occluded without any predicting abnormalities on their last duplex examination, which was performed within 3 months from the occlusion in the majority of the patients. In the 27 occluded bypasses, no intervention was necessary following the occlusion in 7 grafts because of mild or no symptoms. Two patients were treated with a primary amputation and 2 had new bypasses. In 16 occluded grafts, salvage of the PTFE bypass was attempted. Ten of these grafts were patent at the end of the follow-up. The sensitivity of duplex surveillance was 25% with a positive predictive value of 61.5%. CONCLUSION: Duplex surveillance of infrainguinal PTFE bypass grafts has a low yield and is inadequate at predicting continued bypass patency.

Optimal methods for autogenous bypass to the anterior tibial artery.

BACKGROUND: Autogenous bypass to the anterior tibial artery (AT) has been increasingly used for infrageniculate revascularization. The conduit may be routed through the interosseous membrane, a pretibial tunnel, or through a lateral thigh and calf tunnel. This study reviewed results of AT bypass to determine the optimal routing method. METHODS: One hundred thirty consecutive vein grafts to the AT were analyzed retrospectively to compare the experience with the interosseous (group I; n = 50), pretibial (group II; n = 51), and lateral (group III; n = 29) routing alternatives. RESULTS: Indications were claudication in 16 (12.3%) and critical ischemia in 114 (87.8%) procedures with no differences among routing subgroups. Ectopic nonreversed and composite conduits were more common in group III. Major operative morbidity occurred after 7 procedures (5.4%) with no differences in early graft failure (7.7% overall) among the three routing subgroups. Wound infections were more common among group I patients, but without predilection to the interosseous tunnel. During a mean follow-up of 24.9 months (0 to 111.2) overall 5-year secondary patency was 70% with no difference among routing technique. CONCLUSION: Optimal routing choice depends on the location of suitable AT, the length of adequate vein conduit, and the surgeon's preference rather than on factors inherent to the method used.

Renal arteries covered by aortic stents: clinical experience from endovascular grafting of aortic aneurysms.

OBJECTIVES: During the endovascular repair of abdominal aortic aneurysms (AAAs), effective anchoring of the stent-graft is difficult in the presence of a short infrarenal aneurysm neck. The aim of this study was to investigate renal artery patency and renal function after deployment of graft anchoring stents across the renal arteries. DESIGN: Retrospective open study. PATIENTS: Twenty-five renal arteries, in 18 patients treated by endovascular exclusion of an AAA, were intentionally covered with the Gianturco Z-stent to ensure stent graft attachment. METHODS: Renal artery patency was assessed by repeated spiral computed tomography (CT) scans and angiography. Creatinine levels, blood pressure and antihypertensive medication were recorded. Follow-up was a median 6 months (2-9). RESULTS: All 25 stent-covered renal arteries remained patent. CT showed a small infarct in one kidney. Creatinine was 108 mumol/l (89-133) before intervention and 98 mumol/l (87-127) at follow-up. Blood pressure was 150/80 mmHg on both occasions. Antihypertensive therapy was intensified in one patient whose creatinine level remained stable and whose separate renin sampling was normal. CONCLUSIONS: Covering the renal arteries with the Gianturco Z-stent does not seem to affect renal function within 6 months. Further follow-up is needed before suprarenal stent deployment can be advocated.

Mesocaval interposition shunting in the treatment of bleeding oesophageal varices.

OBJECTIVE: To assess the longterm results of mesocaval interposition shunt in the treatment of bleeding oesophageal varices. DESIGN: Retrospective study. SETTING: University hospital, Sweden. SUBJECTS: 60 patients with bleeding oesophageal varices in all Child's classes. 20 of whom were operated on as emergencies, and 40 as elective cases. INTERVENTIONS: A 14 mm polytetrafluoroethylene graft was used as an interposition shunt between the superior mesenteric vein and the vena cava. MAIN OUTCOME MEASURES: Rebleeding rate, portal blood flow, hepatic encephalopathy, morbidity, mortality, and survival. RESULTS: Rebleeding was rare and occurred mainly during the first 4 months after operation, (n = 5) in 10% of the patients, and at the 24 month follow-up, (n = 4) in 11% of the patients. Portal flow was measured preoperatively in 33 patients and in 22 (67%) it was hepatopetal. During follow-up it was reversed and after 24 months no patient had hepatopetal flow. Hepatic encephalopathy was present in 18 patients (20%) during follow-up. Shunts thrombosed in 9 patients (15%), 8 of which required reoperation. There was no operative mortality, but 4 patients (7%) died within 30 days of surgery. The main late cause of death (18/26) was liver failure. The 1 year survival was 80%, the 3 year survival 70% and the 5 year survival 60%. CONCLUSIONS: The mesocaval interposition shunt gives good longterm results and can be recommended both as an emergency and an elective procedure for patients with portal hypertension and bleeding oesophageal varices that are unresponsive to sclerotherapy.

Surgical reconstruction of the iliac arteries prior to endovascular aortic aneurysm repair.

PURPOSE: To explore a method of combined endovascular/conventional treatment of abdominal aortic aneurysm (AAA), in which the iliac arteries are reconstructed by conventional surgical techniques to provide the anatomic substrate for subsequent endovascular repair of the aortic aneurysm. METHOD: A 77-year-old patient with severe cardiac disease was found to have a 6.5-cm AAA, bilateral common iliac artery (CIA) aneurysms, and diffusely narrowed, tortuous external iliac arteries. The left internal iliac artery was occluded. At operation, the right CIA was exposed through a transverse retroperitoneal incision under epidural anesthesia. An iliobifemoral bypass was constructed using a preformed bifurcated graft. A stent-graft was delivered through the right limb of the bifurcated iliobifemoral graft. The proximal end of the stent-graft was implanted in the neck of the aneurysm, and the distal end was deployed in the common trunk of the iliobifemoral graft, thereby excluding the AAA and both native iliac arteries from prograde arterial flow. RESULTS: Completion angiography and follow-up contrast computed tomography showed the aneurysm to be excluded from the circulation. The patient was not intubated, was never hemodynamically unstable, and had aortic blood flow interrupted for no more than 20 seconds. In addition, he was able to resume his usual diet on the first postoperative day. He continues to be well and without evidence of endoleak at 6-month follow-up. CONCLUSIONS: This case demonstrates that iliac artery stenosis, tortuosity, and aneurysmal dilatation are not impediments to endovascular AAA exclusion. Any necessary surgical modifications of pelvic arterial anatomy can be performed before stent-graft insertion to minimize aortic occlusion time.

Local anaesthetic for lower-limb revascularization in high-risk patients.

BACKGROUND: A few patients with critical limb ischaemia are believed to be too unfit for an attempt at revascularization using conventional anaesthesia. METHODS: A retrospective analysis was undertaken of 46 revascularization procedures performed in high-risk patients for critical limb ischaemia between 1989 and 1995, in which local anaesthetic techniques were utilized in preference to general or spinal anaesthesia. RESULTS: Cumulative survival rates at 6, 12 and 24 months were 67, 57 and 51 per cent. Primary patency rates were 77 per cent at 6 months, 67 per cent at 12 months and 53 per cent at 24 months, with associated limb salvage rates of 87, 87 and 79 per cent. CONCLUSION: Selective use of local anaesthetic techniques extends the benefits of limb salvage to patients considered unfit for conventional anaesthesia.

Atrially based pericardial tunnel for central pulmonary artery construction.

Discontinuity of central intrapericardial pulmonary arteries requires reconstruction of a pulmonary artery confluence before cavopulmonary connection, whether this connection be by bidirectional Glenn or Fontan procedure. Reconstruction of the central pulmonary arteries has previously been described using material of poor or no growth potential. A method is described for central pulmonary artery reconstruction that provides growth potential and is based on previous experience with Fontan lateral tunnel construction.

Endovascular stent graft repair of aortic aneurysms.

Vascular surgeons are increasingly encountering older patients with large aneurysms associated with severe comorbid conditions. This situation can increase operative morbidity and elevate the mortality rate of aortic surgery over 60%. With some frequency many patients will represent a prohibitive risk for conventional graft replacement. The endoluminal treatment of 110 patients has proved to be feasible and may represent an alternative solution. One hundred six of the patients had an abdominal aortic aneurysm and in four patients, the thoracic aorta was involved. All of them underwent endoluminal repair for the aortic pathology using the combination of stents and grafts in aorto-aortic or aorto-iliac position, with straight, tapered, or bifurcated stent-graft devices. The results are as follows: Initial success was 84% in aorto-aortic abdominal devices and 100% in aorto-aortic thoracic devices. In aorto-iliac devices, initial success was 75%. Late success rates were 62% of the initial group and 80% of the initially successful group.