Tratamiento de la insuficiencia cardíaca avanzada mediante trasplante de corazón / Heart transplantation as a treatment for advanced heart failure

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...

Endarterectomía carotídea bajo anestesia regional: experiencia inicial / Carotid endarterectomy under regional anesthesia: initial experience

Background: Endarterectomy is the treatment of choice for internal carotid artery critical stenosis. Some authors have proposed that the use of regional anesthesia has advantages over general anesthesia. Aim: To report our initial experience with carotid endarterectomy under regional anesthesia. Patients and methods: Between 1998 and 1999, patients with critical carotid artery stenosis, asymptomatic or with transient and recovered symptoms, were selected. A C2, C3, C4 root deep cervical block and superficial block was performed, using a mixture of lidocaine and bupivacaine. A carotid endarterectomy with patch and without routine shunt insertion, with standard and neurological monitoring, was performed. Results: During the study period, 94 carotid endarterectomies were done, 22 under regional anesthesia in 21 patients (12 male, age range 58-90 years old). Ninety five percent had hypertension, 52 percent smoked and 38 percent had renal dysfunction. One patient was converted to general anesthesia. Seventeen patients were discharged within 48 hours of the procedure and the rest, within 72 hours. There was no mortality or complications. Conclusions: Endarterectomy under regional anesthesia is less invasive, has excellent results and is well accepted by patients

Cirugía coronaria mínimamente invasiva / Minimally invasive coronary artery surgery

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

Efectos de la hemodilución normovolémica sobre la presión arterial central y periférica / Effects of the normovolemic hemodilution on central and peripheral blood pressure

Estudiamos el efecto de la hemodilución normovolémica sobre la presión arterial y periférica. A once perros anestesiados con pentobarbital y ventilados mecánicamente se les midió con catéteres Millar la presión arterial central y periférica, ubicando transductores en aorta y arteria femoral superficial respectivamente. En aorta torácica se instaló transductor electromagnético de flujo. Se administró fenilefrina (FNF) 0,4 y 1 µg/kg. y nitroprusiato (NTP) 2 y 4 µg/kg. Se midió presiones asistólica, diastólica y media, tanto central como periférica, así como flujo medio y presión crítica de cierre (PCC). La PCC se determinó por extrapolación del decaimiento exponencial de la presión arterial cuando el flujo sanguíneo se detuvo mecánicamente. Estas mediciones se realizaron en condiciones basal y alcanzado el máximo efecto de las drogas. Luego se realizó hemodilución extrayendo 30 a 35 ml/kl de sangre, y reponiendo suero fisiológico temperado, manteniendo constante la presión arterial sistólica. Finalmente se procedió a repetir las drogas vasoactivas y las mediciones hemodinámicas respectivas. La hemodilución disminuyó la PCC y la resistencia, con el consecuente aumento el flujo, sin alterar la presión arterial media. La disminución en la resistencia ocurrió independientemente de si en su cálculo se consideró o no la PCC. los efectos de FNF y NTP sobre la presión arterial central y periférica estuvieron de acuerdo a su farmacología y se mantuvieron después de la hemodilución. Sin embargo, hemodilución más NTP disminuyó la diferencia entre las presiones arteriales sistólicas periférica central. Estos resultados nos sugiere que la PCC está determinada, en parte, por las características reológicas de sangre

La ecuación de resistencia vascular sistémica es errónea / The equation used to calculate systemic vascular resistance is wrong

El cálculo habitual de resistencia vascular sistémica (SVR) asume que la circulación se comporta como una resistencia, o sea, que relaciona en forma lineal los valores de presión y flujo medios. Por analogía con la ley de Ohm se utiliza la ecuación SVR=(PAM-PVC)/DC, es decir, la caída de presión entre los territorios arterial y venoso dividida por el débito cardíaco. Esta ecuación es usada universalmente en clínica y en investigaciones fisiológicas, aunque debiera ser obvio que es una sobre símplícación. La definición matemática de resistencia es la pendiente de la función presión/flujo, la que resulta difícil de determinar en pacientes. Para establecer si la ecuación SVR=(PAM-PVC)/DC es apropiada, determinamos experimentalmente la relación presión/flujo en 30 pacientes bajo circulación extracorpórea. La relación encontrada no correspondió a la ecuación arríba citada, ya que la presión a flujo cero (P0) resultó en todos los pacientes significativamente mayor que PVC. La pendiente de la relación presíón/flujo determinada experimentalmente, o sea la resistencia propiamente tal corresponde en realidad a la ecuación R=(PAM P0)/DC. Usando esta fórmula se obtienen valores de resistencia menores que usando la ecuación habitual, y no se confirma que la resistencia sea inversamente proporcional al débito cardíaco, como ha sido publicado

Proteción renal en pacientes de cirugía cardíaca con disfunción renal pre-operatoria: dopamina vs presión de perfusión / Renal protection for patients with preoperative renal dysfunction undergoing cardiac surgery: dopamine vs perfusion pressure

Se estudiaron prospectivamente 17 pacientes con función renal preoperatoría alterada (creatininemia plasmática> 1,5 mg/dl) sometidos a cirugía con circulación extracorpórea. Los pacientes fueron randomizados a dos esquemas de protección renal. Grupo 1: Dopamina 2 ug/kg/min y grupo 2: Presión de perfusión elevada (70 mm Hg) durante circulación extracorpórea. Se midió filtración glomerular y flujo plasmático renal efectívo como clearances de inulina e 1251-hippuran, antes de la anestesia, durante la disección de la arteria mamaría, en circulación extracorpórea (hipotermia y normotermia), cierre del esternón y una hora del postoperatorío. Se midió además díuresís, electrolitos en sangre y orina, y clearances de creatinina, osmolar y de agua libre. La filtración glomerular durante la cirugía, antes de circulación extracorpórea, fue signifícativamente mayor en el grupo dopamina. Hubo tendencia a la disminución de la filtración glomerular durante la fase de hipotermia en ambos grupos. Por otra parte, el flujo plasmático renal efectivo aumentó discretamente respecto del control durante hipotermia en ambos grupos. Se encontró diferencias significativas entre ambos grupos durante cirugía, antes de circulación extracorpórea, en volumen urinario G1 (2,00 ñ 1,67 mL/min) vs G2 (0,29 ñ 0,19 mL/min), osmolaridad urinaria G1 (370 ñ 11 mL/min) vs G2 (627 ñ 157 mL/min), clearance osmolar G1 (2,15 ñ 1,42 mL/min) vs G2 (0,68 ñ 0,37 mL/mín), y potasio urinario G1 (33,1 ñ 12 mEq/L) vs G2 (71,1 ñ 23,7 mEq/L). Estos hallazgos sugieren un efecto de la dopamina sobre factores prerrenales en estos pacientes, ya que en los pacientes que no recibieron dopamina los valores encontrados son sugerentes de vasoconstricción renal

Revascularización miocárdida con una y dos arterias mamarias: resultados clínicos y seguimiento alejado / Myocardialrevascularization with 1 or 2 mammary arteries: clinical results and long term follow up

Patients and methods: One hundred and eight randomly selected patients who received one mammary artery for myocardial revascularization and 108 patients, matched for prognostic factors, who received two mammary arteries were studied. These patients were followed for a mean of 4 years (range 1 to 12 years). Operative complications, hospital mortality and long term probability of being free of disease were compared in both groups. Results: Operative mortality was similar in both groups (0,9 percent). Patients that received two mammary arteries had a higher frequency of operative wound complications. Long term survival was 84 per cente in patients who received one and 83 per cente in patients who received two mammary arteries. The probabilities of being free of myocardial infarction (92 and 82 percent respectively) and angina (94 and 86 percent respectively) were lower in the later group. Conclusions: Patients who received two mammary arteries had a higher probability of a long term disease free survival than patients who received one mammary artery

Aneurisma aórtico abdominal: evolución de la morbimortalidad de la cirugía electiva durante 20 años / Abdominal aortic aneurysm: morbimortality evolution of elective surgery during 20 years

Abdominal aortic aneurysms (AAA) usually undergo progressive dilatation and eventually may rupture,complication that caries a high mortality rate. If certain clinical conditions, like operative risk and aortic diameter are met, all patients should be considered for surgical repair. Analysis of our results with the surgical treatment of asymptomatic AAA prompted this stydy. Our of 479 consecutive patients operated because of AAA between 1976 and 1995, 378 (79 percent) were electively treated. Two decades: 1976-85 (101 patients) and 1986-95 (277 patients) were compared as far as associated medical conditions, surgical procedures, complications and mortality rate. There was no difference in age, sex, risk factors and aortic diameter. During the second decade we favoured the use of aortic tube grafts (53 percent vs 25 percent, p < 0.01) and epidural anesthesia (95 percent vs 35 percent, p < 0.01). During the last decade only 53.3 percent of the patients received blood transfusion, compared to 95.3 percent during the first period (p < 0.001). Operative mortality decreased from 5.94 percent to 0.72 percent (p < 0.05). Postoperative hospital stay diminished from 11.2 ñ 8.2 to 9.6 ñ 6.3 days (p < 0.05). These results compare favourable with those reported from other academic centers and support our therapeutic approach. Our contemporary surgical results serve as a reference for future clinical evaluation of endovascular procedures currently under investigation

Tromboendarterectomía pulmonar: tratamiento quirúrgico del tromboembolismo pulmonar crónico bajo paro circulatorio con hipotermia profunda en un caso / Pulmonary thromboendarterectomy: surgical treatment of chronic pulmonary thromboembolism under circulatory arrest and with deep hypothermia in 1 case

Pulmonary thromboendarterectomy under circulatory arrest and deep hypothermia is presently a curative treatment for pulmonary hypertension secondary to chronic pulmonary artery thromboembolic occlusion, but is still not frequently performed around the world. We report here the first successful pulmonary thromboendarterectomy under circulatory arrest performed in Chile. The patient was a 37 years old white man, high school teacher, with a 5 months history of effort dyspnea and cough. Pulmonary hypertension secondary to chronic pulmonary thromboembolism was confirmed by angiography and echocardiography. The patient was operated on april 27, 1995. After the operation the patient had an enmediate and maintained normalization of his pulmonary hemodynamics. He presented periods of delirium that postponed mechanical ventilation disconnection until the 7th postoperative day, after which he had an uneventful neurological recovery. Before hospital discharge a control angiography showed complete patency of the pulmonary artery system with no evidence of residual thrombi. Presently he is enjoying a normal life and back to his teaching activities

Cirugía de revascularización miocárdica en los primeros 15 días de evolución del infarto / Miocardial revascularization surgery in the first 15 days of infarction evolution

Revascularization significantly improves early and late prognosis in acute myocardial infarction and has prompted substantial changes in therapeutic strategies. We report 140 patients aged 60.3 years old (123 male) operated within 15 days of sustaining an acute myocardial infarction, between january 1984 and december 1989. Coronary angiogram showed single vessel disease single vessel disease in 8 (6 percent), double vessel disease in 32 (23 percent), triple vessel disease in 85 (61 percent) and left main vessel disease in 13 (9 percent). Indications for surgery were ponstinfarction angina in 92 patients (66 percent), multiple severe coronary stenosis in 18 (13 percent), infarction of less than six hours from onset in 16 (11 percent), acute angioplasty failure in 7 (5 percent) and cardiogenic shock in 7 (5 percent). Thirty one patients were operated during the initial 24 h of infarction (16 with less than 6 h) 14 between the second and third day and 95 between the fourth and fifteenth day. Overall mortality was 4.3 percent (6/140). Among patients with failed angioplasty and cardiogenic shock, mortality was 23 percent (7/140), among patients with postinfarction angina this figure was 2.1 percent (2/92). Five years actuarial survival was 95 percent and the actuarial probability of being free of acute myocardial infarction, angioplasty or reoperation at five years was 99 and 100 percent respectively. It is concluded that early surgical revascularization in acute myocardial infarction is safe and has excellent long term results

Perfusión cerebral retrógrada durante paro circulatorio con hipotermia profunda: nueva técnica para la protección encefálica en cirugía de aorta ascendente y arco aórtico / Retrograde cerebral perfusion during circulatory arrest with deep hypothermia: new technique for encephal protection in aortic arch and ascendent aorta surgery

Between may 1993 and august 1994, 15 patients (10 men) with type A aortic dissection (9 acute) had a replacement of the ascending aorta and/or aortic arch with circulatory arrest with profound hypothermia and retrograde cerebral perfusion. Mean circulatory arrest time was 47.5 min (range 23 to 68 min). Three patients (20 percent) died in relation to postoperative bleeding. No patient had a new neurologic damage related to surgery. Ten patients were awake and oriented before 24 hours of the operation and another one before 48 hours; 4 patients required more than 48 hours to be completely awake and oriented. Two patients were operated on with a recent stroke. One of them recovered without sequelae before hospital discharge and the other one had a major regression of his brain damage. Two other patients had emergency surgery because of cardiac tamponade and cardiogenic shock. Both of them had a satisfactory recovery. Six patients presented azotemia but only 2 of them needed dyalisis. There was no case of Q wave infarction nor congestive heart failure in the perioperative period. Follow-up was 100 percent completed (12 patients) with a mean of 9.8 months (range 5 to 18 months). One patient died on the 10th postoperative month because of a late infectious process. Eight patients are in functional class I and 3 in II. Ten of them are back to their usual activities. Although retrograde cerebral perfusion is a new surgical technique, it seems to be a very valuable complement for brain protection in ascending aorta and/or aortic arch surgery with circulatory arrest with profound hypothermia

Relación costo beneficio del uso del tiempo de coagulación activado durante circulación extracorpórea / Cost-benefit ratio of the activated coagulation time useful during extracorporeal circulation

Analizamos retrospectivamente la relación costo-beneficio de dos métodos de anticoagulación sistémica utilizados durante cirugía cardíaca con circulación extracorpórea: dosis protocolizadas de heparina y protamina (Grupo I, n=87) y la determinación seriada de tiempo de coagulación activado (TCA) (Grupo II, n=123). Las dosis totales de heparina y protamina y el gasto en drogas fueron menores en el grupo II, el costo total de la anticoagulación por paciente fue similar en ambos grupos; en el grupo I un mayor porcentaje de pacientes recibió transfusiones de productos sanguíneos; 26,4 por ciento de los pacientes tuvo TCA considerados insuficientes para iniciar la canulación arterial y circulación extracorpórea. El TCA para monitorizar anticoagulación sistémica no aumentó nuestros costos, nos permitió disminuir las dosis de drogas y objetivar y cuantificar la heparinización y su reversión

Ultrafiltración durante circulación extracorpórea / Ultrafiltration during extracorporeal circulation

Se comunica la primera experiencia del servicio en el uso de ultrafiltración durante circulación extracorpórea (CEC) en siete pacientes, tres hombres y cuatro mujeres de edades entre 23 y 69 años, que fueron sometidos a cirugía de urgencia por patología valvular. A su ingreso a pabellón seis presentaban insuficiencia cardíaca refractaria y el restante, anemia hemolítica. Cinco tenían evidencia preoperatoria de disfunción renal. En todos pudo realizarse ultrafiltración, extrayéndose en promedio 2.121 ml de volumen (900-3.850). El balance hídrico final promedio fue de 1.340 ml (-650 a 3.470). Los valores promedio de hematocrito pre-CEC, intra-CEC fueron 30 por ciento, 16,8 por ciento y 24,3 por ciento respectivamente. En la evolución postoperatoria, 6 pacientes presentaron insuficiencia renal aguda oligúrica, requiriendo diálisis cuatro de ellos. Cinco fueron dados de alta en buenas condiciones en un promedio de 32 días (18 a 70). Dos fallecieron alrededor del 11º día, uno por necrosis mesentérica y el otro por shock séptico secundario a endocarditis bacteriana subaguda. La ultrafiltración es una técnica fácil de implementar durante CEC