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Background: When the ascending aorta and the femoral artery cannot be used for extracorporeal circulation, an emerging alternative is the use of axillary artery. Aim: To report the experience using the axillary artery for extracorporeal circulation. Patients and methods: Between November 1998 and May 2002, 22 patients (14 male) were operated with extracorporeal circulation, cannulating the axillary artery. Briefly, an incision is made below the middle third of the clavicle and a cut is made on major pectoris muscle. Minor pectoris muscle is retracted and axillary artery is exposed. It is cannulated directly or with the aid of a prosthesis. Results: Right axillary artery was used in 21 patients and in 20 it was cannulated with the aid of a prosthesis. Mean flow was 4.5 + 0.6 l/min. The most common indications were aortic dissection or aneurysms. The most common procedures done, were ascending aorta replacement in 8 cases and replacement of ascending aorta and aortic arch in 5. Thirty five percent of operations were emergencies and 32 percent were reoperations. In 15 patients (68 percent), a circulatory arrest was done. Of these, retrograde brain perfusion was used in 9, antegrade brain perfusion through the same axillary artery was used in 2 and mixed perfusion was used in 2. One patient had a complication related to the axillary cannulation. None had cerebrovascular accidents or thromboembolic complications. Two patients died in the postoperative period. Patients were followed up to 42 months after the procedure and no secondary complications of the cannulation were detected. Conclusions: When the ascending aorta and the femoral artery cannot be used, axillary artery is a good alternative for extracorporeal circulation

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Background: During the last five years, 65 patients with univentricular heart have been treated surgically in our institution, according to a protocol of staged operations that have been previously reported. Aim: To evaluate the early and mid-term outcome of those patients that have completed their staging protocol by means of a Fontan procedure. Patients and Methods: Between April 1996 and June 2001, 23 patients (age 16 to 223 months) underwent a Fontan procedure, 15 with an intracardiac lateral tunnel technique and 8 with an extracardiac conduit. A retrospective review of their clinical, surgical, echocardiographic, angiographic and hemodynamic data was performed, trying to identify risk factors for both mortality and functional capacity (FC). Follow up was complete in all survivors. Results: Three patients died early after surgery (13.04 percent). Excessive pulmonary blood flow was a risk factor for early death (p= 0.03). One patient died at 14 months. Follow up was 29.9 months (1-63). For those who survived the operation, five years survival was 93.3 percent. The majority of patients are in FC I or II, with no related risk factors. Conclusions: Our current results are comparable with those of larger series. Patients reach good FC and mid-term survival, irrespective of type of single ventricle or the surgical strategy

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Antecendentes: La cirugía es el tratamiento de elección de la coartación aórtica. Sus resultados deben evaluarse no sólo en base de morbimortalidad operatoria si no también en relación a la incidencia de coartación residual y recoartación, hecho que es más frecuente en recién nacidos. Actualmente, dado el interés progresivo en la angioplastia primaria como tratamiento de esta patología se hace necesario conocer los resultados actuales del tratamiento quirúrgico. Objetivo: Analizar y reportar nuestra experiencia en el subgrupo de pacientes de mayor riesgo. Método: Se analizaron retrospectivamente todos los pacientes de hasta 3 meses de edad (menores de 120 días) sometidos a cirugía de coartación aórtica en nuestra institución, entre enero de 1989 y agosto de 1999. Se efectuó un análisis descriptivo de las características generales y de la técnica quirúrgica, así como de los resultados inmediatos y alejados. Resultados: Cincuenta y nueve pacientes fueron sometidos a reparación quirúrgica de la coartación aótica. La edad fue de 35ñ33 días, correspondiendo un 57 por ciento a recién nacidos. Treinta y seis pacientes (61 por ciento) eran del sexo masculino. El peso fue de 3.650ñ1.057 g. La coartación aótica se presentó en forma aislada en 28 pacientes (47,5 por ciento), asociada a CIV en 7 (11,9 por ciento) y a otra patología intracardíaca en 24 (40,7 por ciento). Treinta y seis pacientes (61 por ciento) presentaron unarco aórtico normal, 17 hipoplasia del istmo (28,8 por ciento) y 6 hipoplasia del arco transverso (10 por ciento). La principal indicación de cirugía fue insuficiencia cardíaca. Al momento de la cirugía 17 pacientes (31,5 por ciento) se encontraban en ventilación mecánica y 20 (37 por ciento) habían recibido de protaglandinas. La técnica quirúrgica fue: anastomosis término-terminal en 31 (52,5 por ciento); anastomosis término-terminal extendida en 24 (40,7 por ciento) y colgajo subclavio en 4 (6,7 por ciento). El tiempo de clampeo aórtico fue de tomosis fue de 18,4ñ6,2 minutos. En siete pacientes (11.9 por ciento) se efectuó cirugía cardíaca adicional. Cuatro pacientes (6,7 por ciento) presentaron coartación aórtica residual la cual motivó cirugía en un caso (1,7 por ciento) y angioplastia en otro. Ningún paciente presentó paraplejia. La mortalidad quirúrgica a 30 días fue de 3,4 por ciento (2 casos). Siete pacientes (11,8 por ciento) fallecieron durante el seguimiento, obteniéndose una sobrevida actuarial a 5 años de 83,9 por ciento

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Background: The implantation of pacemakers improves cardiac function and quality of life, in particular with dual chamber DDD and DDDR modes. Aim: To evaluate our clinical experience and results on pacemaker implantation, from 1963 to 1998. Material and methods: Computerized data collected from 2,445 consecutive paced patients was reviewed. A total of 3,554 operative procedures were performed, including 412 procedures for complications and 697 pacemaker replacement. Patient survival was determined from clinical records, inquiry to pacemaker manufacturers and death certificates from Servicio de Registro Civil e Identificaci-n de Chile (Chilean Civil and Identification Registry). Results: Use of dual chamber (DDD and DDDR) pacemakers increased progressively up to 74 percent from 1988 to 1998. Complication rate was 42 percent in the 1963-1976 study period, it decreased to 10.6 percent in the 1977-1987 study period, and to 5.6 percent by 1988-1998. Only two patients died during surgery in the study period (0.08 percent). In the 1977-1987 period, pacemakers lasted 10.6 years. Survival rates were 52 percent at ten years, 33 percent at 15 years, and 21 percent at 20 years, with a median survival of 11.7 years, and 7.24 years in patients over 80 years old. Conclusions: Transvenous permanent pacing can be accomplished today with a low complication rate, mainly due to better technology and surgical procedures

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Background. Ischemic mitral regurgitation (IMR) is a severe condition which may be best treated by surgery, nowithstanding a relatively high mortality rate. Objectives. To evaluate the results of mitral valve replacement or repair in patients with IMR. Patients and methods. Retrospective review of the clinical records in 29 patients with IMR who were surgically treated from 1990 to 1999. They represent 8 percent of surgical procedures on the mitral valve. Results. Mean age was 67 ñ 9 years. Surgery was performed urgently in 19 patients (66,5 percent). NYHA functional class was 3.4 ñ 0.8. The mechanism of IMR was annular dilatation and spreading of papillary muscles in 18 patients, papillary muscle rupture in 9 and fibrosis in 2. Mitral valve replacement was performed in 14 patients and mitral valve repair in 15. Twenty four patients (83 percent) had concomitant myocardial revascularization. Overall surgical mortality was 24 percent; 26 percent for mitral replacement and 13 percent for mitral valve repair (p=0.215). On follow up of 26ñ33 months, one year survival was 76ñ0.8 percent and 5 years survival was 59ñ12 percent. Excluding in hospital mortality, survival was 100 percent at one year and 78ñ14 percent at 5 years. Functional class improved in all survivors, to 1.4ñ0.5. Late echocardiographic evaluation of patients with mitral valve repair showed absence of mitral regurgitation in 58 percent, 1+ MR in 17 percent and 2+ MR in 25 percent. Conclusion. In spite of a high perioperative mortality, surgery for IMR is a valuable procedure for patients with an otherwise highly lethal disease

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Background: Coronary artery bypass grafting (CABG) reoperation is being performed with increasing frequency. Aim: To assess the early and long term results of coronary reoperations in our institution and to identify prognostic factors. Patients and methods: 214 patients subjected to coronary reoperations between 1983 and 1999 were retrospectively studied. Results: Mean age was 64.2 years (range 42-79 years), 202 (94.4 per cent) were male and 12 (5.6 per cent) female. The mean interval between the operations was 125.7 months (range 6-252 months). 10 (4,6 per cent) were emergency surgeries. Overall operative mortality was 5.6 per cent (11 deaths) and in 5 patients (3.4 per cent) a perioperative myocardial infarction was noted. Univariate analysis identified moderate or severe left ventricular failure (p=0.048) as predictor of increased operative mortality, meanwhile age over 75 years (p=0.02) and moderate or severe left ventricular failure (p=0.01) were identified as predictors of increased in hospital mortality in the multivariate analysis. Follow up of in hospital survivors (mean interval 65 months, range 4 to 190 months) documented a 5 years survival rate of 82.9 per cent, a 10 years survival rate of 73.1 per cent and a 15 years survival rate of 53.4 per cent. Moderate or severe left ventricular failure (p <0.0001) and emergency surgeries (p=0.007) were identified as factors influencing the late survival in the stepwise logistical regression analysis. Multivariate analysis identified left ventricular failure (p=0.01) and peripheral vascular disease (p=0.01) as predictors of decreased late survival. Conclusions: Coronary reoperation has a low mortality in patients with a normal ventricular function and also has an excellent overall and disease free survival in the first 10 years of follow up. Left ventricular function is an independent risk factor increasing in hospital and late mortality

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Background: Heart transplantation currently provides the most effective treatment for advanced heart failure. However, medical therapy for this condition has also improved, heart donors are scarce and the cost of the procedure is high. Therefore the indications and management of these patients need reevaluation. Aim: To analyze the results of 24 patients submitted to heart transplantation for end-stage heart failure needing repeated hospitalizations and i.v. inotropes for compensation. Patients and methods: The group was comprised by 21 men and 3 women with a mean age of 36.8 years, mean left ventricular ejection fraction 19ñ4.5 percent, mean systolic pulmonary artery pressure 48ñ13 mmHg (24-70) and mean pulmonary vascular resistance 2.6 Wood Units (1-5). Fourteen patients (58 percent) had a previous median sternotomy. Immunosupression did not include induction therapy and steroids were discontinued early...

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Heart transplantation is a therapeutic alternative for selected patients with refractory heart failure. Acute allograft rejection is one of the main causes of early death after transplantation. The cellular rejection is characterized by cellular infiltrates with or without miocyte necrosis. However, some patients develop left ventricular dysfunction due to rejection without evidence of cellular infiltration. In these patients, the rejection is mediated by antibodies and complement. Humoral rejection is a relative rare but potentially fatal form of acute allograft rejection. We report two patients with left ventricular dysfunction secondary to humoral rejection, shortly after cardiac transplantation. Both patients were treated with methylprednisolone, and azathioprine was substituted by cyclophosphamide. One patient underwent plasmapheresis. The clinical outcome was satisfactory and the left ventricular function returned to normal in both cases. The diagnostic and therapeutic strategies for the management of humoral rejection are reviewed

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René Favaloro MD, was born in La Plata, Argentina, in July 1923. He studied medicine in La Plata and made his cardiology residence in the Cleveland Clinic, where he developed coronary bypass surgery for the treatment of ischemic heart disease. At the present time, this surgical procedure is a well recognized therapy for coronary artery disease that has benefited millions of patients. Back in Argentina, he founded in 1992 the Institute of Cardiology and Cardiovascular Surgery that had an important research and teaching activity. Dr Favaloro wanted to be remembered as a teacher rather than as a surgeon, but he really was a great Master of Surgery in the Americas

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Background: It is known that the sympathetic varicosities co-store and co-release norepinephrine (NE) together with adenosine S-triphosphate (ATP) and neuropeptide Y (NPY). Aim: To describe the chemical characterisation of stored and released NPY from the varicosities of sympathetic nerve terminals surrounding segments of the human saphenous vein, and the vasomotor activity of rings electrically depolarized or contracted by the exogenous application of the co-transmitters. Material and methods: Saphenous vein tissues were obtained from patients undergoing elective cardiac revascularization surgery. Results: The chromatographic profile of NPY extracted from biopsies is identical to a chemical standard of human NPY. Upon electrical depolarisation of the perivascular sympathetic nerve terminals, we demonstrated the release of NPY to the superfusion media, which did not exceed a 1percent of its stored content. The release of the peptide is sensitive to guanethidine, and to extracellular calcium, suggesting that the mechanism of its release is exocytotic in nature. The electrically evoked release of NPY is dependent on the frequency and duration of the electrical pulses. Phenoxybenzamine reduces the electrically evoked release of NPY. Exogenous application of NE and ATP contract saphenous vein rings; the simultaneous application of NE plus ATP causes a synergic response, effect which is further potentiated by the joint co-application of 10 nM NPY. Conclusions: Present results highlight the role of NPY as a sympathetic co-transmitter in the regulation of human vascular tone

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En este estudio caracterizamos la liberación de NPY de biopsias de la arteria y vena mamaria. Se induce la liberación de los neurotransmisores por medio de despolarización eléctrica de los nervios simpáticos perivasculares. Con estímulo de 70 V, 0,5 msec, 40 Hz por 5 min, segmentos de la arteria mamaria liberan 17,7 ñ 6,7 fmol (n=4) de NPY, la vena libera 4,3 ñ 1,5 fmol (n=4), valores que corresponden a un 1-2 por ciento del NPY en la biopsia. El NPY liberado por estímulo eléctrico no es metabolizado en la sinapsis neuroefectora. La liberación del NPY al medio de superfusión tiene un curso temporal lento, la máxima liberación ocurre a los 10 min del estímulo. La liberación del NPY es dependiente de la duración del estímulo (coeficiente de correlación = 0,647, p<0,01); y de la frecuencia de estimulación (coeficiente de correlación = 0,611, p<0,05), indicando que la liberación es un proceso controlado por la frecuencia de la descarga y por la intensidad del estímulo simpático vasomotor. El proceso de liberación es dependiente del calcio, ya que en ausencia de calcio extremo, la liberación de NPY se reduce en 78 por ciento. El NPY actúa sobre receptores postsinápticos, donde produce un efecto facilitador significativo de la acción vasomotora de NA y ATP. En conclusión, NPY se libera al espacio sináptico por exocitosis, donde participa junto a NA y ATP en la regulación del tono vasomotor simpático

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Background: Surgical repair is the procedure of choice for mitral insufficiency since it preserves better left ventricular structure and function. Aim: To assess the long term clinical and echocardiographic results of mitral valve reconstructive surgery. Material and methods: A review of clinical and echocardiographic data of 68 patients (34 male, age range 17 to 82 years), subjected to surgical mitral valve repair between december 1991 and march 1998. Preoperative functional capacity of these patients was 2.96 ñ 0.7. Surgical repair was assessed using transesophagic echocardiography in all subjects. Results: The etiology of mitral insufficiency was degenerative in 43 patients, rheumatic in 10, infectious in 6, ischemic in 5 and miscellaneous in 4. The most frequent pathological findings were dilatation of the mitral ring in 42 percent of patients, chordae tendinae rupture in 32 percent and enlargement in 24 percent. A mitral anuloplasty was done in 90 percent of patients, a cuadrilateral resection of posterior leaflet in 52 percent and chordae tendinae transference in 12 percent. An additional surgical procedure was done in 34 percent of subjects. Three patients died during hospitalization (4.4 percent). During the follow up of 36.5 ñ 22.3 months, five patients died and one required a mitral valve replacement. The actuarial survival probability was 95.3 ñ 2.6 percent at one year and 83.5 ñ 6.5 percent at five years. The reoperation free survival was 100 percent at one year and 97.4 ñ 2.5 percent at five years. At the end of follow up the functional capacity improved to 1.25 ñ 0.4. echocardiography showed absence of mitral insufficiency in 48.4 percent of patients, minimal, mild and moderate insufficiency in 35.5, 14.5 and 1.6 percent of patients respectively. Conclusions: Surgical valve reconstruction in mitral insufficiency has satisfactory long term results and should be the procedure of choice for eligible patients

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Objetivos: el uso de una miniesternotomía para la reparación de ciertas cardiopatías congénitas tendría beneficios cosméticos, menor dolor postoperatorio y una hospitalización más breve, sin sacrificar los resultados de la intervención. Nuestro objetivo es describir la técnica quirúrgica y presentar los resultados de una serie inicial de pacientes. Material y método: desde enero de 1998 adoptamos la técnica de miniesternotomía para el cierre de comunicación interauricular (CIA) en pacientes pediátricos. Desde entonces, hasta diciembre de 1998 se intervinieron 16 pacientes (mujeres: 8; hombres: 8), de entre 9 meses a 13 años de edad (x:3,5 años), con peso de entre 8 a 36 kg (x:15,4 kg). Trece pacientes presentaban una CIA tipo ostium secundum, 2 una CIA tipo ostium primum con cleft de la válvula mitral y 1 paciente una CIA tipo seno venoso-cava inferior. Se describe la técnica quirúrgica. Resultados: en 8 pacientes se realizó cierre directo del defecto y en 8 se empleó parche de pericardio; en 2 se cerró un cleft mitral. En ningún paciente fue necesario ampliar la estemotomía. El tiempo de circulación extracorpórea fluctuó entre 20 a 76 minutos (x:49,5) y el clampeo aórtico entre 7 a 53 minutos (x:20,5). El ecocardiograma pre-alta no demostró defectos residuales en ningún paciente. La estadía hospitalaria postoperatoria fue entre 3 y 4 días y el dolor fue subjetivamente menor. No hubo morbilidad ni mortalidad. Comentario: la miniesternotomía permite un adecuado y seguro acceso para la reparación de CIA en pacientes pediátricos, con buenos resultados cosméticos, corta estadía hospitalaria y aparentemente menos dolor. Esta técnica tendría ventajas sobre el uso de toracotomía anterior derecha y puede utilizarse para reparar otros defectos, como comunicación interventricular y canal auriculoventricular completo

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Antecedentes: desde mediados de la presente década se han propuesto distintos accesos mínimamente invasivos en cirugía cardiovascular, entre ellos la miniesternotomía. Objetivo: presentar nuestra experiencia inicial en cirugía valvular a través de miniesternotomía. Pacientes: entre octubre 1997 y diciembre 1998, se efectuó un reemplazo valvular aórtica y en otra un reemplazo valvular mitral, a través de una miniesternotomía media en "J". Nueve pacientes eran hombres. El promedio de edad fue de 53,6 años (29-73). Todos los pacientes fueron operados con monitorización ecocardiográfica transesofágica. Técnica quirúrgica. Se efectuó una esternotomía media en "J" en el 3º o 4º espacio intercostal derecho con una incisión cutánea menor a 10 cm en todos los casos. Para el retorno arterial se canuló la aorta ascendente y para el drenaje venoso, la orejuela derecha con una cánula única. La protección miocárdica se efectuó con cardioplegia cristaloide infundida en forma anterógrada y/o retrógrada a 4ºC. El drenaje de las cavidades izquierdas se efectuó con un catéter introducido a través de la vena pulmonar superior derecha. Los reemlazos valvulares aórticos se efectuaron a través de una aortotomía oblicua y el reemplazo valvular mitral a través de una auriculotomía izquierda superior...

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Background: There is a growing interest to perform a left internal mammary artery (LIMA) graft to the left anterior descending coronary artery (LAD) on a beating heart through a minimally invasive access to the chest cavity. Aim: To report the experience with minimally invasive coronary artery surgery. Patients and methods: Analysis of 11 patients aged 48 to 79 years old with single vessel disease that, between 1996 and 1997, had a LIMA graft to the LAD performed through a minimally invasive left anterior mediastinotomy, without cardiopulmonary bypass. A 6 to 10 cm left parasternal incision was done. The LIMA to the LAD anastomosis was done after pharmacological heart rate and blood pressure control and a period of ischemic pre conditioning. Graft patency was confirmed intraoperatively by standard Doppler techniques. Patients were followed for a mean of 11.6 months /7-15 months). Results: All patients were extubated in the operating room and transferred out of the intensive care unit on the next morning. Seven patients were discharged on the third postoperative day. Duplex scanning confirmed graft patency in all patients before discharge; in two patients, it was confirmed additionally by arteriography. There was no hospital mortality, no perioperative myocardial infarction and no bleeding problems. After follow up, ten patients were free of angina, in functional class I and pleased with the surgical and cosmetic results. One patient developed atypical angina on the seventh postoperative month and a selective arteriography confirmed stenosis of the anastomosis. A successful angioplasty of the original LAD lesion was carried out. Conclusions: A minimally invasive left anterior mediastinotomy is a good surgical access to perform a successful LIMA to LAD graft without cardiopulmonary bypass, allowing a shorter hospital stay and earlier postoperative recovery. However, a larger experience and a longer follow up is required to define its role in the treatment of coronary artery disease

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Las soluciones de cardioplejia han reducido en forma significativa el daño isquémico del corazón asociado a la cirugía cardíaca. Sin embargo, existe controversia sobre cual es el tipo de solución ideal. En este estudio comparamos la efectividad entre la solución extracelular de St. Thomas Nº 1 (ST) y la solución intracelular de Bretschneider (BT). En ratas Sprague-Dawley se evaluó la función cardíaca in vitro por el método del corazón aislado de Langerdorff. Los corazones fueron perfundidos con (10ml/kg) de la solución ST o BT, los que posteriormente fueron evaluados luego de 0 horas (sham), 1 hora y 4 horas de isquemia preservados a 4ºC. A un grupo control sin isquemia no se perfundió cardioplejia. Las soluciones se compararon evaluando la incidencia de arritmias, el flujo coronario, la contractilidad (pendiente de la relación tensión-elongación sistólica desarrollada), y distensibilidad miocárdica (cambio de volumen diastólico del ventrículo izquierdo en un rango de presión diastólica entre 0 y 25 mmHg). La solución de BT preservó mejor (p<0,05) la contractilidad miocárdica que la solución de ST, tanto a la hora como a las cuatro horas de isquemia. Por otra parte, a las cuatro horas de isquemia la solución de BT preservó mejor (p<0,05) la distensibilidad miocárdica que la solución de ST. No hubo diferencias en la incidencia de arritmias o en el flujo coronario entre los grupos experimentales. Nuestros resultados muestran que la solución de BT preserva mejor la función sistólica y diastólica que la solución de ST luego de 4 horas de isquemia

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Background: Since the first surgical coronary revascularization done in Chile in 1971, 5000 such procedures bave been performed. Aim: To assess the long term results of coronary revascularization surgery in our institution and to identify prognostic factors. Patients and methods: Five groups of 100 patients each, composed by the first consecutive patients subjected exclusively to coronary bypass surgery in the years 1975, 1980, 1985, 1990 and 1995 were retrospectively studied. Results: Mean age of Patients increased from a median of 52 years old in 1975 to 62 yean old in 1995. No changes in the frequency of diabetes, hypertension, high serum cholesterol or prvious mycardial infarction were observed. There was an increase in the Proportion of patients with a recent (< 30 days) infarction that were operated along time. Seventy percent of patients had triple vessel disease or LMT and this proportion did not change. The number of grafts per patients increased form 1.9 to 3.4 and the use of arterial conduits from 0.18 to 0.81. Perioperative mortality remained constant and was 1.6 percent. Follow up information was obtained for 93 percent of 492 survivors. Actuarial survival at 5, 10, 15 and 20 years was 93ñ1, 82ñ2, 62ñ3 and 41ñ4 percent respectively. Ninety eight ñO.7, 89ñ2, 73ñ4 and 65ñ5 percent of patients remained free of a new myocardial infarction in the same lapses, respectively. Ninety seven ñl, 94ñ2, 76ñ4 and 47ñ7 percent of patients remained free of a new operation. Stepwise logistical regression analysis identified as bad Prognostic factors, in decreasing order: cardiac failure, diabetes, smoking, hypercholesterolemia and age at the moment of operation. Conclusions: Coronary artery bypass surgery provides good and long lasting clinical improvement. The prognosis of patients is influenced by the presence of cardiac failure, some well known coronary risk factors and age at the moment of operation

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