Factores determinantes en la aparición de fibrilación auricular post-cirugía de revascularización miocárdica: un estudio prospectivo / Risk factors for postoperative atrial fibrillation after coronary artery bypass grafting: a prospective analysis

Background: Atrial fibrillation (AF) is a relevant complication after coronary artery bypass grafting (CABG). However there is controversy regarding possible contributing factors. Aim: To study the incidence of AF, its risk factors and its repercussion on hospital stay and charges, in patients undergoing CABG. Material and methods: We prospectively collected information from all patients undergoing CABG in our institution, including demographic, surgical and laboratory variables. Exclusion criteria were chronic AF, recent onset AF and patients who needed additional surgical procedures. The primary endpoint was the incidence of AF during the hospital stay. Secondary endpoints were hospital length of stay and hospital charges. Results: We included 250 patients aged 62±9 years (199 males) in the analysis. Incidence of AF was 22 percent (54 patients). Multivariable analysis showed that age (Odds Ratio (OR) =1.10), previous CABG (OR =9.39), previous use of ACE inhibitors (OR =3.28) and aortic clamp >57 minutes (OR =3.97) were significantly associated with an increased risk of postoperative AF. Previous use of beta-blockers was associated with risk reduction (OR =0.43). Patients who developed AF had a longer hospital stay (p <0.001) and higher hospital charges (p =0.003). Conclusion: AF is a frequent complication in patients undergoing CABG. Risk factors are age, time of aortic clamp, previous CABG and ACE inhibitors. Beta-blockers may prevent its occurrence. Furthermore, AF has a negative impact on both hospital stay and hospital charges.

Criocoagulación de venas pulmonares como tratamiento complementario de la fibrilación auricular en cirugía valvular / Cryoablation of pulmonary veins as complementary treatment of atria I fibrillation in valvular surgery

Background: The Cox MAZE III operation for the treatment of atrial fibrillation (AF) is complex and consumes significant operative time. Cryoablation of the pulmonary veins (CPV) is a simpler alternative for patients that require concomitant valvular surgery. Aim: To evaluate CPV in patients with AF submitted to valvular surgery. Patients and Methods: Twenty one patients had simultaneous valvular surgery and CPV, 81 percent of them had permanent AFfor an average of 5 years. Twenty patients had mitral valve disease. The etiology was rheumatic in 14. Average left atrial diameter was 60 mm. In 7patients the mitral valve was replaced, in 5 it was repaired, in 7 both mitral and aortic valve were replaced, in 1 the mitral valve was repaired and the aortic valve was replaced and in 1 only the aortic valve was replaced. A combined transeptal and superior approach was used for all patients. The CPV was performed after the valvular procedure with cryothermy at -60°C for 2 minutes with two 15 mm cryoprobes applied simultaneously. Results: CPV increased surgical time by 10 to 20 minutes. Operative mortality was 4.8 percent (1 patient). One patient developed a pericardial effusion and another a complete heart block that required a permanent pacemaker. All patients improved their functional class. At the end of an average 10.5 months of follow-up, 50 percent of patients were in normal sinus rhythm and 25 percent persisted in AF. The remaining patients were in some type of regular rhythm. Conclusions: CPV as a complementary procedure in patients with AF undergoing valvular surgery had good results to abate AF. It restored normal sinus rhythm in 50 percent of the cases, with low morbidity and mortality and little increment in surgical time.

Asistencia ventricular mecánica como puente al trasplante en pacientes en shock cardiogénico: Experiencia preliminar en Chile con ABIOMED BVS 5000® / Ventricular assist device as a bridge to transplant in patients with cardiogenic shock: Report of four patients

Hospitalization and death due to heart failure and cardiogenic shock is frequent and currently is increasing among the adult population. Although cardiac transplantation is the most effective treatment in patients with end-stage heart failure, its availability is limited. While waiting for transplantation, some patients become refractory to treatment and deteriorate progressively. Secondary multi-organ damage could highly compromise the transplant success and also could contraindicate it. Mechanical ventricular assist devices allow reestablishing normal cardiac output and they have been used as a bridge to recovery and transplantation. We report four patients that underwent mechanical ventricular support using the ABIOMED BVS 5000® system as a bridge for transplantation. Two patients were connected to biventricular assistance; a third patient was connected to a left ventricular support and the fourth to a right ventricular support. Three were successfully transplanted and one died of refractory non-cardiogenic shock. There were no complications related to the support system, such as infection, hemorrhage or stroke. In our experience, the ABIOMED BVS 5000® was an effective strategy as a bridge to heart transplant in patients in cardiogenic shock.

Reemplazo parcial o total del arco aórtico: Experiencia en 23 pacientes / Partial or total replacement of the aortic arch: Experience in 23 patients

Background: Surgery of the aortic arch is a very complex procedure since it requires protective strategies for the brain, heart and rest of the body. Aim: To communicate our experience in the first 23 total or partial replacements of aortic arch. Material and methods: Retrospective search in the database of the Cardiovascular Surgery Unit for patients subjected to partial or total replacement of the aortic arch since 1998. Results: Between 1988 and 2002, 23 patients were operated. Seventeen had aortic dissection (10 acute and 7 chronic), five had an atherosclerotic aneurysm and one had a traumatic lesion. Thirteen patients were subjected to a replacement of the arch plus ascending aorta, six to a replacement of the arch plus descending aorta and four to a replacement of the arch, ascending and descending aorta. Seven patients had previous operation of the thoracic aorta. Arterial perfusion was done via the femoral artery, axillary artery or a combination of both. A hypothermic circulatory arrest was induced in 22; it was associated with cerebral retro perfusion alone in 8 patients, antegrade cerebral perfusion in 5; isolated or associated axillary perfusion was used in five patients. In seven, procedures on the aortic or mitral valve, or coronary artery operations were added. Operative mortality was 26%, 3 of the 8 patients operated as an emergency and 3 of 15 elective operations. There was no mortality among those without dissection and of 7 chronic dissections, one died. All patients were followed for an average of 45 months. Two patients required reinterventions on the aorta and one for colon cancer. There was one late death of unknown cause. Postoperative complications were agitation, bleeding and temporary vocal cord dysfunction. Conclusions: There is a learning curve, where more extensive operations, particularly those done as emergency or for dissections, had an increased operative risk.

Falla cardio respiratoria severa tratada con asistencia cardiopulmonar extracorpórea: caso clínico / Treatment of severe respiratory failure with cardiopulmonary extracorporeal assistance

Cardiopulmonary extracorporeal assistance is a high complexity procedure for patients with acute respiratory failure, who have failed conventional ventilatory support. A 30 years old female patient with bacterial endocarditis and congestive cardiac failure subjected to cardiac surgery presented severe hypoxemia, right heart failure and pulmonary hypertension, and failed conventional treatment. Cardiopulmonary support with extracorporeal membrane oxygenation (ECMO) reverted the pathophysiologic alterations allowing a successful recovery

Reoperaciones coronarias: análisis retrospectivo de 16 años de experiencia / Coronary artery bypass grafting reoperation: a 16 years retrospective analysis

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

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...

Un sistema de alarmas inteligentes para vigilancia continua durante cirugía y postoperatorio cardiovascular / An intelligent system of alarm for continuous monitoring during cardiac surgery and postoperative intensive care

Se presenta un sistema experto capaz de integrar la información de siete variables fisiológicas de pacientes en cirugía y postoperatorio cardiovascular. El sistema está basado en lógica difusa y funciona bajo condiciones de información ruidosa o incompleta. El estado del paciente es estimado por medio de análisis simultáneo de las variables e integración de ellas. Las alarmas son reportadas en forma unificada por medio de un mensaje escrito en la pantalla. El sistema fue implementado en un computador personal para vigilancia continua y simultánea de hasta 9 pacientes. El sistema fue comparado con monitores convencionales (SpaceLabsTM PC2) en 20 cirugías cardíacas. Las alarmas reportadas por cada sistema fueron registradas por dos observadores expertos (un médico, un ingeniero) y clasificadas como verdaderas o falsas. Un 75 por ciento de las alarmas reportadas por los monitores convencionales fueron falsas, mientras que menos de un 1 por ciento de las alarmas reportadas por el sistema experto fueron falsas. La sensibilidad de los monitores convencionales fue de 79 por ciento y la del sistema experto de un 92 por ciento. El valor predictivo positivo fue un 31 por ciento con los monitores convencionales y un 97 por ciento con el sistema experto. En conclusion, la confiabilidad de las alarmas mejoró significativamente al integrar información de varias variables, reduciendo notablemente la frecuencia de alarmas falsas. La lógica difusa fue una herramienta poderosa y útil para integrar información fisiológica

Disección aguda de la aorta ascendente / Acute dissection of the ascending aortic

La disección aguda de la aorta ascendente (DAAA) constituye una patología con cifras de mortalidad que alcanzan al 25 por ciento a 24 hrs y más del 50 por ciento a la semana. La reparación quirúrgica precoz es la única alternativa de tratamiento eficaz. Sin embargo, su morbimortalidad continúa siendo elevada. En los últimos años ésta ha disminuido por la introducción de nuevas técnicas quirúrgicas y de manejo intraoperatorio. Entre 1985 y junio de 1997 operamos 65 pacientes (pts) con DAAA, 45 hombres (70 por ciento), edad promedio 52,2 ñ 13,1 años. Un 66 por ciento eran hipertensos y 14 por ciento tenían Síndrome de Marfán. El dolor fue el síntoma de presentación en 94 por ciento y un tercio de los pts se presentó con insuficiencia aórlica masiva o taponamiento en shock cardiogénico. Como examen diagnóstico se utilizó el TAC en 36 pts, angiografía en 27, ecocardiograma de superficie en 40 y transesofágico en 29. La localización más frecuente de la ruptura intimal fue la aorta ascendente (75 por ciento). Un 72 por ciento de los pts fueron operados con menos de 24 h de evolución. En 37pts se utilizó el paro circulatorio en hipotermia profunda y en 28 se asoció perfusión cerebral retrógrada. Los tiempos promedio de CEC, clampeo aótico y paro circulatotio fueron 170, 96 y 40 m, respectivamente. En todos los pts se reemplazó la aorta ascendente, además el arco proximal en 3. En 11 se utilizó un tubo compuesto. En 9 se efectuó RVA y suspensión de velos en 22. En 5 se agregó bypass coronario y en 15 se reimplantó uno o ambos ostium coronarios. La mortalidad operatoria global fue 24 por ciento (16/65). Desde 1995 ha disminuido a 12 por ciento (2/16). Las complicaciones post operatorias fueron: sangramiento 12, IRA y diálisis 3 y AVE en 3 pts. Se completó el seguimiento a un 97 por ciento de los pts con un promedio de 35 meses; tres pts fallecen de progresión de su enfermedad aneurismática y 7 de otras causas. La sobrevida actuarial a 5 años fue de 78 por ciento. En conclusión: nuevas técnicas quirúrgicas y de manejo intraoperatorio sumado a la experiencia acumulada, han permitido disminuir la morbimortalidad perioperatoria en la DAAA y ofrecer adecuada sobrevida a mediano plazo

Cirugía coronaria: veinte años de seguimiento / Results of coronary surgery: a 20 years experience

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

Aneurismas micóticos y embolías múltiples en una paciente con endocarditis infecciosa / Mycotic aneurysms and multiple emboli in a patient with infectious endocarditis

Sepsis from an infected cardiac value can lead to bacterial seeding and destruction of the arterial wall with formation of a mycotic aneurysm. The natural history of these lesions is the rupture. We report the case of a 20 year old female who was admitted to our institution with massive mitral regugirtation and emboli of the central nervous system and both lower extremities. She underwent emergency valve replacement and then, staged treatment of her ischmic legs and multiple asymptomatic mycotic aneurysms. Superior mesenteric, right common iliac and left superficial femoral arteries. A splenectomy was required to treat a splenic abscess. An aneurysm of a peripheral branch of the middle cerebral artery was medically treated, demonstrating reduction in size on subsequente angiogram.She recoverd uneventfully and remains asymptomatic after 20 months of follow up. The development of new diagnostic and therapeutic tools had led to a decrease ot these complications during infectious endocarditis. However, in the patient with late diagnosis and symptoms in different territories, the mycotic aneurysm must be kept in mind to provide the patient with appropriate treatment

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

Indices predictores del retiro precoz de ventilación mecánica en pacientes sometidos a cirugía cardíaca / Predictor rates of early mechanical ventilation withdrawal in patients submitted to cardiac surgery

To study the capacity to predict successful early extubation of ventilatory and gas exchange parameters, 230 patients admitted to an intensive care unit after coronary or valvular surgery were studied. Measurements were made through a T piece 30 minutes after discontinuing mechanical ventilation. Six patients died in the postoperative period. Two hundred ten patients tolerated early extubation (14ñ5 h of mechanical ventilation) and 20 required prolonged mechanical ventilation (74ñ107 h). The latter had longer surgical procedures (291ñ65 and 240ñ67 min respectively) and extracorporeal circulation times (138ñ42 and 104ñ43 min respectively), required more vasoactive drugs, had more episodes of confusion and had a higher surgical risk. Tidal volume, respiratory frequency, maximal inspiratory pressure and blood gases at the moment of extubation were similar in both groups. Pulmonary function parameters and blood gases measured during a T piece trial are not good predictors of early extubation in cardiac surgery

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

Evolución de las indicaciones, técnica quirúrgica y resultados de la revascularización miocárdica / Changes in the indications, surgical techniques and results of myocardial revascularization surgery

Durante los últimos 20 años, las indicaciones y técnica quirúrgica de la revascularización miocárdica han evolucionado en forma importante, por lo cual nos ha interesado estudiar estos cambios y su influencia sobre los resultados obtenidos en pacientes sometidos a este tratamiento quirúrgico. Con este objeto, se analizaron los factores clínicos (edad, capacidad funcional, antecedentes mórbidos, factores de riesgo y patologías asociadas), la cinecoronariografía selectiva, la técnica quirúrgica, y los resultados de la intervención (mortalidad, morbilidad y estadía hospitalaria) de 400 pacientes de un total de 2.410 casos intervenidos entre 1970-1990. Estos pacientes fueron divididos en cuatro grupos que incluyen los primeros cien pacientes operados en forma consecutiva de puente aortocoronario exclusivo (electivos o urgencias) durante los años 1975 (grupo I), 1980 (grupo II), 1985 (grupo III) y 1990 (grupo IV). Los cambios observados en la técnica quirúrgica incluyeron el uso progresivamente mayor de la arteria mamaria interna (20%, 12%, 60%, 86%, respectivamente), el uso de magnificación óptica en el grupo II y siguientes y luego hipotermia a 25§C y cardioplejía usados en los grupos III y IV. La edad promedio, el porcentaje de pacientes mayores de 70 años, de pacientes intervenidos con infarto reciente (<30 días) de enfermos con lesión de tres vasos, y de pacientes que recibieron tres o más puentes aortocoronarios, fueron progresivamente mayores en el tiempo, y comparados los grupos entre sí, la diferencia tuvo significancia estadística (p<0,001). En cambio, la estadía intrahospitalaria postoperatoria fue decreciente durante el período analizado (14, 12, 9 y 9 días, respectivamente) y la morbilidad y mortalidad permanecieron estables, esta última en el 1%. Concluimos que la cirugía de revascularización miocárdica se ha ido efectuando en pacientes progresivamente más graves y con factores de riesgo mayores, manteniendo la morbimortalidad estable

Muerte súbita en el adulto joven sin cardiopatía demostrable: características clínicas y electrofisiológicas en 3 casos / Sudden cardiac death in 3 young patients without overt heart disease

We reported 3 young adult males who developed spontaneous ventricular fibrillation in the abscence of demonstrable heart disease. Extensive clincial and elelcrophysiilogic evaluation failed to disclose a cause for the arrhythmia. Antiarrhythmic drugs were empirically used in all patients but 2 of then eventually died. Thus, unexplained ventricular fibrillation without demonstrable heart disease carries a serious short term prognosis. An implantable cardiovertodefibrillator may be the therapy of choice in these cases