RESUMO
Toda especialidad médica, y en especial las quirúrgicas, necesitan, de alguna manera, vislumbrar el futuro que puedan ofrecer a los miembros más jóvenes de la especialidad y eventuales interesados en esta, de manera de asegurarles las mejores posibilidades de desarrollo profesional y personal, para, a su vez, poder reclutar a los mejores. Empero, para imaginar y forjar el futuro, es necesario vivir y enfrentar el presente. Pero, todo presente se asienta en un pasado, que es necesario conocer y meditar. Y de esto trata este artículo especial: pasado, presente y futuro de la cirugía de corazón, desde la particular visión de su autor.
Every medical specialty, mainly surgical specialties, needs to envision the future they can offer to the specialty's younger members and those eventually interested in it to assure them of the best possibilities for professional and personal development and, in turn, to be able to recruit the best one. However, it is necessary to live and face the present to imagine and forge the future. But every present is based on a past, which must be known and meditated upon. This article is about the past, present, and future of heart surgery, according to the particular vision of its author.
RESUMO
Si bien pudiera parecer que desde siempre el corazón fue el centro de la vida y de la espiritualidad del hombre, esto no es exactamente así. A lo largo de la historia, debió competir con otros órganos por esta posición. Su primer competidor fue el hígado, especialmente en Babilonia. Para los babilonios, el hígado, una masa grande, inmóvil en la cavidad abdominal, era el órgano ideal para que los dioses hicieran saber el futuro. Sin embargo, los egipcios eligieron al corazón como el órgano central de la vida y asiento del alma y le atribuyeron toda clase de facultades. En Israel, es el pulmón donde radica la vida. La característica de este no son las palpitaciones, sino la respiración. Dios crea a Adán soplándole Su aliento en la nariz. Pero el competidor más serio fue el cerebro. Los filósofos y médicos griegos van a discrepar, dando origen a una larga controversia. La discusión se termina con Aristóteles, quien afirma que, al igual que el mundo tiene un punto central, también el hombre lo tiene, y este es el corazón. Y así es hasta cinco siglos más tarde, en que Galeno vuelve a sostener que la vida mental y espiritual del hombre se asienta en el cerebro. Sin embargo, hasta hoy, hombres y mujeres siguen sintiendo que su espíritu habita en el corazón y que el centro de la vida es el corazón, puesto que el corazón simboliza lo más propio del hombre, el amor.
Though it could seem that the heart has always been the center of life and spirituality of man, this is not exactly so. Along history the heart had to compete with other organs for this position. Its first competitor was the liver, specially in Babylonia. For the Babylonians, the liver, a big, immobile mass in the abdominal cavity, was the ideal organ for the gods to make the future known. On the other hand, the Egyptians chose the heart as the central organ of life and seat of the soul, and attributed to it all kinds of faculties. In Israel the lung was the site where life took root. The distinctive features of life were not the throbs but the breathing. God created Adam blowing His breath into Adams nose. But, the most serious competitor was the brain. The Greek philosophers and physicians had different opinions, giving origin to a long controversy. The discussion was settled by Aristotle, who stated that as the world has a central point, man also has one, and this is the heart. This remained so for five centuries until Galen declared that the brain is the seat of mental and spiritual life of man. However men and women up to today continue feeling that their spirit inhabits in the heart and that the center of their life is the heart, since it symbolizes love, an inherent faculty of man.
Assuntos
Humanos , Coração , História da Medicina , Amor , Espiritualidade , Encefalopatias , Fígado , Pulmão , FilosofiaRESUMO
The first surgical procedure for the treatment of coronary artery disease, in 1933, was total thyroidectomy. Some years later, procedures to increase heart irrigation such as pectoral or great epiplon grafting and cardiopeumopexy were attempted. In 1940, the ligation of great cardiac vein or coronary sinus were introduced. Five years later, pericoronary neurectomy was used. In 1945, Beck used an arteriovenous fistula between the descending aorta and the coronary sinus and, from 1954, he used the erosion of heart surface with asbestos application, complemented with the occlusion of the coronary sinus and the application of parietal pericardium. In 1958, Glover introduced the bilateral ligation of mammary arteries and Vineberg, developed the internal mammary artery implant, that consisted in the tunneling of the free portion of such artery in the myocardium. En 1956, Lillehei and Bailey introduced coronary endarterectomy and finally in 1967, Favaloro introduced systematically the aortocoronary bypass using safenous vein, that became the definitive surgical treatment for coronary artery disease. In Chile the first coronary surgery was done by Torwall and Uribe in 1950 and modern coronary surgery was initiated by Salvestrini in1970
Assuntos
Doença das Coronárias/cirurgia , Procedimentos Cirúrgicos Cardiovasculares/história , Ponte de Artéria Coronária/história , História da MedicinaRESUMO
The echocardiographic identification of cardiac tumors as cause of embolic episodes is infrequent, and the finding of multiple papillary fibroelastoma is even less common. We report a 70 years old female with a history of a rheumatic mitral valve lesion, subjected to a commissurotomy in 1970. She was admitted with a cerebrovascular accident and the transesophageal echocardiogram revealed the presence of a multiple papillary fibroelastoma in the aortic valve. The patient was operated and the tumor excised, the pathological analysis confirmed the diagnosis. The patient was discharged in good conditions and after 8 months of follow up, she has no neurological abnormality and is in functional class I
Assuntos
Humanos , Feminino , Idoso , Acidente Vascular Cerebral , Fibroma , Neoplasias Cardíacas , Acidente Vascular Cerebral , Fibroma , Neoplasias Cardíacas , Ecocardiografia Transesofagiana , Estenose da Valva Aórtica/cirurgia , Estenose da Valva Aórtica , Músculos Papilares , Procedimentos Cirúrgicos CardíacosRESUMO
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
Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Rejeição de Enxerto/fisiopatologia , Oclusão de Enxerto Vascular/fisiopatologia , Transplante de Coração/efeitos adversos , Metilprednisolona/administração & dosagem , Linfócitos T/efeitos dos fármacos , Rejeição de Enxerto/tratamento farmacológico , Hipertensão/complicaçõesRESUMO
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
Assuntos
Humanos , Neuropeptídeo Y , Sistema Nervoso Simpático/fisiologia , Transmissão Sináptica/fisiologia , Veia Safena/patologia , Veia Safena , Biópsia , Monoaminas Biogênicas/farmacologia , Norepinefrina/farmacologia , Estimulação Elétrica Nervosa TranscutâneaRESUMO
Mediastinitis with graft infection is a serious complication of ascending aorta replacement. We report two cases of graft infection, treated with surgical cleaning, graft preservation and transposition of muscle flaps. A 62 years old male was admitted 34 days after an ascending aortic grafting due to a sternal dehiscence and mediastinitis. Antimicrobial treatment was started and a surgical cleaning performed, leaving an open sternotomy. Three days later, the thoracic cavity was closed with a rectus abdominis muscle flap. After 23 months of follow up, the patient is well and without evidence of infection. A 74 years old male was subjected to an aortic valve and ascending aorta replacement and a myocardial revascularization. In the postoperative period, the patient developed septic signs, and a purulent drainage. A CAT scan showed a liquid collection surrounding the aortic graft. On tW Sixteenth postoperative day, a surgical cleaning was performed and the thorax was closed with the pectoralis major muscle. After 10 months of follow up, the patient is in Good condition and without evidence of infection
Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Aorta/microbiologia , Infecções Relacionadas à Prótese/terapia , Próteses Valvulares Cardíacas/microbiologia , Sobrevivência de Enxerto/imunologia , Mediastinite/microbiologia , Obesidade/complicações , Retalhos Cirúrgicos , Síndrome de Resposta Inflamatória Sistêmica/terapiaRESUMO
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
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Insuficiência da Valva Mitral/cirurgia , Procedimentos de Cirurgia Plástica , Mortalidade Hospitalar , Circulação Extracorpórea/métodos , Ecocardiografia Transesofagiana , Insuficiência da Valva MitralRESUMO
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
Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Implante de Prótese de Valva Cardíaca , Insuficiência da Valva Mitral/cirurgia , Complicações Pós-Operatórias , Intervalo Livre de Doença , Complicações Intraoperatórias , Revascularização MiocárdicaRESUMO
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
Assuntos
Humanos , Masculino , Pré-Escolar , Feminino , Lactente , Técnica de Fontan , Cardiopatias , Derivação Cardíaca Direita/estatística & dados numéricos , Período Pós-Operatório , Intervalo Livre de Doença , Comunicação Interventricular , Disfunção Ventricular/cirurgia , HemodinâmicaRESUMO
Traumatic rupture of the aorta has a near 80 percent mortality. Most patients die on the site of the accident. Conventional surgical repair of these lesions has a high morbidity and mortality, generally associated to the severity of associated lesions. Over the last decade, endovascular treatment has become an effective therapeutic alternative. We report a 40 years old male, that suffered a traumatic rupture of the descending thoracic aorta in a car accident. A successful endovascular repair was performed, installing an endoprothesis on the site of the lesion, using a femoral artery approach. The patient had a good postoperative evolution and was discharged from the hospital once complete rehabilitation of his associated lesions was obtained
Assuntos
Humanos , Masculino , Adulto , Aorta Torácica/lesões , Implante de Prótese Vascular/métodos , Ruptura Aórtica/cirurgia , Acidentes de Trânsito , Traumatismos Torácicos/cirurgia , Traumatismos Torácicos/complicaçõesRESUMO
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
Assuntos
Humanos , Masculino , Adulto , Feminino , Pessoa de Meia-Idade , Artéria Axilar , Circulação Extracorpórea/métodos , Cateterismo , Doenças Cardiovasculares , Aneurisma Aórtico/cirurgia , Coartação Aórtica/cirurgiaRESUMO
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...
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Insuficiência Cardíaca/cirurgia , Transplante de Coração/métodos , Sobrevivência de Tecidos , Estudos Prospectivos , Rejeição de Enxerto , Sobrevivência de Enxerto , Imunossupressores/uso terapêutico , Hemodinâmica , Hipertensão/complicações , Insuficiência Cardíaca/complicaçõesRESUMO
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
Assuntos
Humanos , Masculino , Feminino , Marca-Passo Artificial , Doenças Cardiovasculares , Síndrome do Nó SinusalRESUMO
Para los pacientes con insuficiencia cardíaca avanzada la única alternativa terapéutica efectiva es el trasplante cardíaco. Sin embargo, dadas las características epidémicas de la insuficiencia cardíaca, la demanda por corazones nuevos excede con mucho la oferta de éstos. De aquí el interés por dirigir los esfuerzos hacia nuevas opciones de tratamiento quirúrgico que puedan ser una alternativa efectiva al trasplante cardíaco. En la actualidad estas alternativas están constituidas por la cirugía convencional de alto riesgo, la cardiomioplastía dinámica, la ventriculectomía izquierda parcial, los dispositivos mecánicos de asistencia ventricular izquierda y los xenotrasplantes. La cirugía convencional de alto riesgo (cirugía coronaria y anuloplastía mitral) es cada vez más aceptada como alternativa al trasplante cardíaco a pesar de su supuesta mayor morbi-mortalidad, en especial como complemento al tratamiento médico. Por el contrario, la cardiomioplastía dinámica, con ya más de 13 años de experiencia clínica, no ha logrado establecerse como un procedimiento alternativo efectivo al trasplante cardíaco, por su elevada mortalidad perioperatoria y post procedimiento y por sus insuficientes resultados en el corto y mediano plazo. La ventriculectomía izquierda parcial, de reciente introducción, no ha cumplido hasta ahora con todas las expectativas que de ella se tenían. Sin embargo, permitiría aproximadamente el 70 por ciento de los pacientes mejoren su capacidad funcional, pudiendo ser su aplicación la de un puente biológico al trasplante cardíaco o un procedimiento definitivo complementario al tratamiento médico, en pacientes no candidatos a trasplante. Por último, los dispositivos mecánicos de asistencia ventricular izquierda se han establecidos como aparatos efectivos como puentes al trasplante cardíaco, si bien con una morbimortalidad y costo económico de consideración. Además, muy recientemente se ha iniciado la evaluación de estos dispositivos como alternativa definitiva al trasplante cardíaco. Más allá de las fronteras de la cirugía cardíaca actual se encuentran los xenotrasplantes, en activa investigación experimental, si bien en 1985 esto fue una realidad. En esta revisión se discuten las publicaciones más recientes y relevantes de las opciones quirúrgicas alternativas al trasplante cardíaco y se describe el procedimiento operatorio de la cardiomioplastía dinámica, la ventriculectomía izquierda parcial y los dispositivos de asistencia ventricular
Assuntos
Humanos , Baixo Débito Cardíaco/cirurgia , Procedimentos Cirúrgicos Cardíacos , Transplante de Coração , Cardiomioplastia , Coração Auxiliar , Disfunção Ventricular Esquerda/cirurgia , Revascularização Miocárdica/métodos , Transplante Heterólogo/métodosRESUMO
La cirugía a corazón abierto, como la conocemos en la actualidad, es un logro del siglo recién pasado. Hasta fines del siglo XIX el corazón era considerado un órgano inasequible y prohibitivo a la cirugía, hasta que en 1896 Ludwing Rehn sutura por primera vez, con éxito, una herida de corazón. En los primeros años del siglo XX la cirugía se limita, con éxito relativo, al tratamiento de las heridas de corazón y luego de las afecciones pericárdicas, hasta que en 1938 Robert Gross liga con éxito un ductus arterioso persistente, operación que se convierte en la chispa que enciende la explosión de la cirugía cardiovascular, a partir de la cual rápidamente se avanza hasta conseguir un tratamiento quirúrgico corrector de la coartación aórtica, para luego desarrollar procedimientos paliativos extracardíacos para malformaciones intracardíacas, como la estenosis pulmonar
Assuntos
Humanos , Cirurgia Torácica/história , Procedimentos Cirúrgicos Cardíacos/história , História do Século XIXRESUMO
En julio de este año falleció Walton Lillehei, MD, PhD, a quién John Kirklin definió como un héroe y un pionero de la cirugía a corazón abierto. Genuino representante de los "cirujanos-fisiólogos", Lillehei desarrolló en 1954 la circulación cruzada controlada, operando exitosamente, por primera vez, entre otras, una comunicación interventricular, un canal aurículo ventricular y una tetralogía de Fallot, lo que cambió radicalmente el pesimismo mundial respecto a la circulación extracorpórea imperante en ese entonces. Meses después Lillehei desarrolló el oxigenador de burbujas, el que permitió la aplicación generalizada de la circulación extracorpórea en la corrección de las malformaciones cardiovasculares congénitas o adquiridas. Además, Lillehei tuvo una importancia fundamental en el desarrollo del marcapaso cardíaco y de 4 prótesis valvulares cardíacas y se adelantó en más de 30 años al concepto de protección miocárdica por perfusión retrógrada del seno coronario y en más de 20 en definir la importancia del aparato valvular mitral en la preservación de la arquitectura y función del ventrículo izquierdo. Esta gran productividad convirtió al programa de la University of Minnesota de Lillehei en el más importante y codiciado de la época, del que salió un gran número de cirujanos cardiovasculares que llegaron a ser jefes de programas ellos mismos o hicieron importantes contribuciones al desarrollo de la cirugía cardiovascular. En 1963 Lillehei visitó Chile, dictando varias conferencias en distintos auditorios de Santiago y efectuando, el 27 de mayo de 1963, una corrección de una comunicación interventricular en los pabellones de cirugía torácica del Hospital Clínico de la Universidad Católica, siendo luego nombrado miembro honorario de la Facultad de Medicina de esa casa de estudios
Assuntos
Humanos , Cirurgia Torácica , Oxigenadores/história , Marca-Passo Artificial/história , Circulação Extracorpórea/história , Próteses Valvulares Cardíacas/históriaRESUMO
En la primera parte de este relato se dio cuenta de cómo los cirujanos, con perseverancia e imaginación, logran diseñar procedimientos quirúrgicos correctores para patologías extracardíacas y procedimientos paliativos para patologías intracardíacas, estableciendo la cirugía cardiovascular como una especialidad propiamente tal. En esta segunda parte revisaremos primero la etapa de la cirugía cardíarca cerrada, en especial la cirugía de la esteneosis mitral, destacando siempre la circunstancias que rodearon a estos cirujanos y las adversidades que debieron afrontar, para llegar finalmente a la cirugía de corazón abierto con circulación extracorpórea, como la conocemos en la actualidad, para lo que previamente fue necesario pasar por la cirugía cardíaca con hipotermia y luego con circulación cruzada controlada, en la que un "donante" humano sano, habitualmente el padre o la madre de un niño, servía como oxigenador
Assuntos
Humanos , Cirurgia Torácica/história , Procedimentos Cirúrgicos Cardíacos/história , Oxigenadores/história , Circulação Extracorpórea/história , Procedimentos Cirúrgicos Cardíacos/instrumentação , Procedimentos Cirúrgicos Cardíacos/métodosRESUMO
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