Predictores preoperatorios de evento cerebrovascular postoperatorio en cirugía de revascularización miocárdica / Perioperative predictors of stroke after coronary artery bypass grafting

El evento cerebrovascular postoperatorio en cirugía de revascularización miocárdica es una entidad catastrófica que aumenta la morbimortalidad y los costos por atención médica. La literatura muestra una disminución en la incidencia del evento cerebrovascular posterior a cirugía cardiaca en la última década, sin embargo no se dispone de datos sobre la prevalencia de esta entidad en Latinoamérica ni en Colombia. Objetivos: Identificar los factores de riesgo para el desarrollo de evento cerebrovascular temprano, en pacientes sometidos a cirugía de revascularización miocárdica en un centro de referencia colombiano. Métodos: Estudio de casos y controles anidado en una cohorte retrospectiva. Resultados: Se incluyeron 876 pacientes, con edad promedio de 63,6 años ± 9,25 años, de los cuales el 74,5% eran hombres. La incidencia de evento cerebrovascular postoperatorio fue 1,3%. Los factores de riesgo fueron: cirugía valvular ( OR 43,92 { IC 95% 1,26-1527,05} , p = 0,037) ; evento cerebrovascular previo ( OR 14,78 { IC 95% 2,96-73,68} p = 0,01) ; calcificación aórtica ( OR 8,23 { IC 95% 2,18-31,12} , p = 0,02) . Conclusiones: La incidencia de evento cerebrovascular postoperatorio de cirugía de revascularización miocárdica en un centro de referencia colombiano es inferior a la que se reporta en la literatura mundial. Los factores predictivos son la cirugía valvular, el antecedente de evento cerebrovascular y la identificación de calcificación aórtica.

Introduction: Perioperative stroke after coronary artery bypass grafting is a catastrophic complication that increases mobility, mortality and the cost for medical attention. Recently a global decrease in perioperative stroke has been reported, however, there is a lack of data about the prevalence of perioperative stroke in Latin-American and Colombia. Objective: To identify the risk factors for early stroke after coronary artery bypass grafting in a Colombian cardiovascular center. Methods: A retrospective case and control study nested in a cohort was performed. Results: 876 patients were included with a mean age of 63.6 ± 9.25 years, 74.5% were male. The incidence of perioperative stroke was 1.3%. The risk factors identified were: previous valvular surgery OR 43.92 ( 1.26-1527.05) , p:.037, past medical history of stroke OR 14.78 ( 2.96-73.68) , p:.01 and the presence of aortic calcification OR 8.23 ( 2.18-31.12) , p:.02. Conclusions: The incidence of perioperative stroke after coronary artery bypass grafting in a Colombian cardiovascular center is lower than reported in the literature, the perioperative predictors identified in the present study were previous valvular surgery, the past medical history of stroke and aortic calcification.

El colágeno de la reestenosis post angioplastia con stent: ¿se origina en la íntima o en la adventicia? / Origin of collagen in restenosis post stenting: intima or adventitia?

Background: Restenosis post stenting is due to the deposit of extracellular matrix, mainly collagen in the neointima. Controversy exists regarding if collagen is generated locally or by immigration from the adventitia. Aim: To study the fibrocellular response after stent implantation in rabbit iliac arteries. To observe, by immunohistochemistry and in situ hybridization, if collagen type I mRNA is expressed in the neointima, in the media or in the adventitia. Material and methods: Thirty eight white rabbits (New Zealand) of 4 kg received an hypercholesterolemic diet during 1 month. After this period, in all but 6 of them, an angioplasty with stent implantation was performed via right carotid artery in both iliac arteries, using a 1:1.3 relationship regarding the reference vessel. Angiograms were performed at day 0, 4, 21, and 40, followed by paraffin fixation of the injured segments, immunohistochemistry for a-actin and in situ hybridization to detect procollagen type I (a1R1) mRNA. Results: No hybridization was observed in non injured arteries or at day 0 (n= 6). Expression of a1R1 mRNA was observed in the neointima starting at day 4 after stenting (n= 8). At day 21 (n= 8) hybridization of procollagen type I was not only observed in the neointima, but also in the media, which became equally intense in both areas. At day 40 (n= 6) hybridization was observed similarly in the media and adventitia. Conclusions: In this model, hybridization of procollagen type I started in the neointima, then involved the media and finally the adventitia. This finding might be useful for designing therapies to be delivered locally at the end of an angioplasty to prevent collagen deposition in the neointima

La hiperuricemia es un marcador del umbral anaeróbico en la insuficiencia cardíaca crónica / Hyperuricemia is a marker for anaerobic threshold in chronic cardiac failure

Background: Patients with chronic cardiac failure often have elevated plasma uric acid levels, that are associated to a dismal prognosis. Aim: To investigate possible metabolic mechanisms to explain elevated uric acid levels in these patients. Patients and methods: Eighteen patients with chronic cardiac failure aged 61 ñ 10 years old, without gout or renal failure and not using high doses of diuretics (equal or less than 80 mg/day furosemide or 50 mg/day hydrochlorothiazide) were studied. Plasma uric acid levels were correlated with anaerobic threshold, maximal oxygen uptake, plasma noradrenaline and creatinine and left ventricular ejection fraction, measured radioisotopically. Results: Mean maximal oxygen uptake was 16.6 ñ 4.2 ml/kg/min. There was a negative correlation between uric acid levels and maximal oxygen uptake or maximal oxygen uptake/body surface area (r=0.521 and -0.533 respectively, p<0.05). Patients with uric acid levels over 7 mg/dl had a lower anaerobic threshold than patients with lower levels (9.81 ñ 2.41 and 13.08 ñ 3.28 ml/kg/min respectively, p<0.05). No significant differences in maximal oxygen uptake were observed in these two groups of patients (15.5 ñ 4.24 and 18.08 ñ 3.86 ml/kg/min respectively). Uric acid levels did not correlate with plasma noradrenaline, creatinine or lefi ventricular ejection fraction. Conclusions: These results suggest that a defect in cellular oxygenation contributes to the elevation of plasma uric acid levels in patients with chronic cardiac failure

Entrenamiento selectivo de los músculos respiratorios en pacientes con insuficiencia cardíaca crónica / Selective training of respiratory muscles in patients with chronic heart failure

Background: Patients with chronic heart failure have a lower inspiratory muscle strength and fatigue endurance. Aim: To assess the effects of selective training of respiratory muscles in patients with heart failure. Patients and methods : Twenty patients with stable chronic heart failure, aged 58.3 ñ 3 years with an ejection fraction of 28 ñ 9 percent, were subjected to respiratory muscle training with threshold valves. The load was fixed in 30 percent of maximal inspiratory pressure (PImax) in 11 and in 10 percent of PImax in nine. Two sessions of 15 minutes, 6 days per week, during 6 weeks were done. Degree of dyspnea (Mahler score), maximal oxygen uptake, distance walked in 6 minutes, respiratory muscle function and left ventricular ejection fraction were measured before and after training. Results: Both training loads were associated to an improvement in dyspnea (+2.7 ñ 1.8 and +2.8 ñ 1.8 score points with 30 percent Plmax and 10 percent PImax respectively), maximal oxygen uptake (from 19 ñ 3 to 21.6 ñ 5 and from 16 ñ 5 to 18.6 ñ 7 ml/kg/min with 30 percent PImax and 10 percent PImax respectively, p< 0.05), PImax (from 78 ñ 22 to 99 ñ 22 and from 72 ñ 34 to 82.3 cm H20 with 30 percent Plmax and 10 percent PImax respectively), sustained PImax (from 63 ñ 18 to 90 ñ 22 and from 58 ñ 3 to 69 ñ 3 cm H20 with 30 percent PImax and 10 percent PImax respectively), and maximal sustained load (from 120 ñ 67 to 195 ñ 47 and from 139 ñ 120 to 192 ñ 154 g with 30 percent PImax and 10 percent PImax respectively). The distance walked in 6 min only increased in subjects trained at 30 percent PImax (from 451 ñ 78 to 486 ñ 68 m). Conclusions: Selective training of respiratory muscles results in a functional improvement of patients with chronic heart failure

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...

Potencia de los músculos inspiratorios en insuficiencia cardíaca crónica y en enfermedad pulmonar obstructiva crónica / Respiratory muscle power output in patients with chronic heart failure and patients with chronic pulmonary obstructive disease

Background: The maximal pressure generated by inspiratory muscles (PIMax) is an index of their strength which is diminished in both chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). Although inspiratory muscle power output (IMPO), which includes both strength and velocity of shortening, has been shown to be reduced in COPD, there is no information regarding IMPO in CHF. Aim: To measure Impo in patients with CHF and COPD. Patients and methods: We studied 9 CHF patients with functional capacity II and III and 9 patients with severe COPD. Eight normal subjects of similar ages were included as controls. Power output was measured using the incremental threshold loading test. Results: Maximal IMPO was significantly reduced in both groups of patients. Power output developed with each increasing load was also diminished, basically as a consequence of a reduction in insp. The degree of dyspnea at the end of the test was greater in COPD than in CHF patients and normal subjects. For a given level of power, dyspnea was also greater in patients than in normals subjects. There was no decrease in SpO2 during the test. Conclusions: IMPO is equally reduced in COPD and CHF patients. Power output is better related to dyspnea than PIMax, probably because of the inclusion of shortening velocity

Angina inestable: resultados inmediatos y a un año del tratamiento con angioplastía coronaria transluminal percutánea / Immediate and late results of transluminal coronary angioplasty in patients with unstable angina

Background: Unstable angina is characterized by angina at rest, angina of recent onset or accelerating angina. It is caused by a fissure or ulceration of an atheromatous plaque leading to thrombi formation and coronary spasm. Aim: To report the immediate and late results of coronary angioplasty in patients with unstable angina. Patients and methods: Eight hundred twenty eight patients were subjected to coronary arteriography between January 1994 and June 1996. Of these, 242 were subjected to a transluminal coronary angioplasty, 245 patients were subjected to surgical revascularization and 341 patients were treated without revascularization. Results: A total of 323 stenotic lesions (1.3 lesions per patient) were subjected to angioplasty. Angiographic success was obtained in 93 percent of patients. Angiographic success and lack of major complications such as death, infarction of the need for surgery, was obtained in 90 percent of patients. Five patients (2.1 percent) had a non fatal infarction and five required emergency surgery. Hospital mortality was 1.2 percent. During the year of follow up, 15 percent required a new revascularization, 3.3 percent had a non fatal infarction and 3.3 percent died. Conclusions: Coronary angioplasty had a 90 percent immediate success and 78 percent of patients were free of ischemic events after one year of follow up

Valor de la biopsia ganglionar en el paciente HIV/SIDA / Value of ganglionar biopsy in VIH/AIDS patient

La linfadenopatía generalizada y persistente (LGP) es parte del espectro clínico general asociado a la infección con HIV, sin embargo una infección oportunista, el sarcoma de Kaposi o el linfoma no Hodgkin podrán determinar también el desarrollo en algunos casos de linfadenopatías; y si bien en el caso de LGP el estudio histopatológico de un ganglio carecería de relevancia, en los otros casos la realización de una biopsia ganglionar podría estar justificada y tener interés desde el punto de vista diagnóstico, terapéutico y pronóstico. Desde marzo de 1990 a marzo de 1996 se estudiaron en el Instituto de Enfermedades Infecto Contagiosas 68 pacientes, 43 portadores de HIV y 25 con Sida, con 69 biopsias ganglionares. Hubo 10 mujeres y 58 hombres. La edad media fue de 39 años con una mediana de 30 años (rango 20-63). Los informes de la anatomía patológica fueron los siguientes: linfopatía crónica 40, tuberculosis ganglionar 17, histoplasmosis 4, criptococosis 2, sarcoma de Kaposi 1, linfoma no Hodgkin 1, metástasis de carcinoma 1, metástasis de melanoma 1 y no adenopatía 2. El seguimiento promedio de los pacientes fue de 38,67 meses (intervalo de confianza 95 por ciento [lC95]: 32, 17-45,17). La biopsia fue de utilidad en 13 oportunidades de 63 casos, lo que representa 20,63 por ciento, habiéndose descartado 6 casos en los que habiéndose encontrado un ganglio con una infección intercurrente, no se habían realizado estudios bacteriológicos, baciloscópico o micológico previo a la biopsia. Se concluye que la biopsia ganglionar estaría indicada cuando no se cuenta con otros recursos para llegar a el diagnóstico de enfermedad intercurrente que determine un cambio en el tratamiento, el inicio de un nuevo tratamiento o confirmar un tratamiento que se estaba haciendo en forma empírica

Efectos cardiovasculares del acortamiento del intervalo AV mediante estimulación eléctrica del corazón en miocardiopatía dilatada / Cardiovascular effects of AV interval shortening with heart electric stimulation in dilated cardiomyopathy

Patients and methods: Nine patients with dilated cardiomyopathy were studied. Hemodynamic and tissular perfusion values, echocardiographic and radioisotopic ventricular function parameters were measured before and after six hours of AV interval shortening with electrical stimulation of the heart. Results: After electrical stimulation, cardiac output increased from 3.38 ñ 0.8 to 32.87 ñ 0.79 l/min (p < 0.05). Pulmonary capillary pressure decreased from 23.8 ñ 8.9 to 19.8 ñ 9.2 mm Hg (p = NS). There were no significant changes in ventricular function parameters or in systemic and pulmonary pressures. Conclusions: Electrical shortening of AV interval in patients with dilated cardiomyopathy increases cardiac output but does not change ventricular function parameters

Factores de urovirulencia bacteriana: asociación con recurrencias y anomalías anatómicas y funcionales en niños con infección del tracto urinario / Urinary bacterial virulence factors: association with recurrence of anatomical and functional abnormalities and urinary tract infection in children

A prospective sample of children was incorporated into a followup protocol after their first episode of bacteriologically-demonstrated urinary tract infection. In all patients an abdominal ultrasound examination and a mictional urethrocystography were done and the presence of fiambriae was studied in isolated strains of Escherichia coli. Two hundred fifteen cases had an adequate adherence to the study protocol, 190 caused by E coli. Fiambristed E coli strains were isolated with greater frequency from children with pyelonephritis than from those with a low urinary tract infection (50 and 28 percent respectively). The absence of fiambriae in E coli strains was associated with a higher risk of recurrent infections (odds ratio=3, confidence intervals=1.1-10.2). These data are consistent with foreign reports and support the need to study adhesins in E coli strains isolated from children with urinary tract infections

Ventilación mecánica no invasiva intermitente: utilidad en el tratamiento de la insuficiencia cardíaca crónica avanzada / Non invasive intermittent mechanical ventilation: utility in the treatment of advanced chronic cardiac failure

The higher respiratory work and less inspiratory muscle strength of patients with cardiac failure may contribute to dicrease their functional capacity. To assess the effects of non invasive intermittent mechanical ventilation on clinical parameters, peropheral perfusion, cardiac and inspiratory muscle function. Patients with chronic cardiac failure, functional cpacity III-IV were subjected to 6 sessions of nasal non invasive intermittent ventilation during 4 hours or to simulated ventilation (controls). Fifteen ventilated patients and 6 controls completed the protocol. Ventilated patients improved the mahler transition score for dysnea by 4ñ1.6 points. They also improved their aerobic capacity, increasing the exercise duration from 10.9ñ4 to 12.7ñ5 min and their maximal oxygen consumption from 14.6ñ4 to 16.4ñ5.7 ml/kg/min. These patients also decreased their O2 and CO2 ventilatory equivalents. Maximal inspiratory pressure increased from 67.9ñ23.6 to 80.19ñ21.4 cm H2O, sustained maximal inspiratory pressure increased from 101.4ñ48 to 133ñ53 cm H2O and maximal endurance increased from 132ñ52 to 162ñ58 g in ventilated patients. None of these variables was modified in control patients. No changes were observed in renal function, blood volume, arterial gases, spirometry or plasma catecholamine levels in any group. Intermittent nasal ventilation or other measures to improve inspiratory muscle function may be beneficial for patients with severe cardiac failure

Características del electrograma local en fulguraciones exitosas de haces paraespecíficos / Characteristics of the local electrogram in successfuly fulgurations of paraspecific bundles

La ablación por radiofrecuencia de haces paraespecíficos es un aterapia muye efectiva para el tratamiento de las taquicardías paroxíticas supraventriculares. Con el objeto de evaluar la utilidad del electrograma local en la identificación del sitio correcto para efecturar la ablación por radiofrecuencia, se analizaron las características de éstos en 20 pacientes con haces paraespecíficos fulgurados exitosamente. 16 pacientes tenían un haz paraespecífico izquierdo (10 ocultos), 2, haz paraespecífico anteroseptal y 1, un haz paraespecífico lateral derecho. En 15 pacientes la fulguración se realizó durante taquicardia paroxítica supraventricular y en 5, durante ritmo sinusal. En los 20 electrogramas analizados, el hallazgo más frecuente fue el de complejos fusionados. Se registró un probable electrograma de Kent en 3 pacientes fulgurados en taquicardia y en 4 pacientes fulgurados en ritmo sinusal. Pensamos que ninguna de las características del electrograma local tiene un valor predictivo alto para precisar el sitio de la fulguración exitosa

Cáncer colorrectal: un estudio prospectivo de base poblacional en la ciudad de Montevideo : resultados preliminares del estudio de incidencia / Colorectal cancer: a prospective population based study in Montevideo : preliminary results of the incidence study

Uruguay comparte con Argentina el dudoso honor de ser los únicos países latinoamericanos con alta mortalidad por cáncer colorrectal. El presente trabajo es el primer estudio de base poblacional del cáncer colorrectal en la ciudad de Montevideo. A través de una estrategia de accesos múltiples cuidadosamente diseñada, todos los nuevos casos de cáncer colorrectal diagnosticados en pobladores habituales del departamento de Montevideo en 1991 fueron registrados, con el fin de lograr un conocimiento adecuado acerca de la incidencia, características clínicas, métodos diagnósticos y terapéuticos y estadificación anátomo patológica de la enfermedad. Se identificaron 554 pacientes, con una relación masculina/femenina de 1:1,07 y una edad promedio de 69 años. De ellos 24 por ciento se presentaron clínicamente como casos de emergencia, 63 por ciento estaban localizados en el colon (49 por ciento en el colon derecho y 51 por ciento en el colon izquierdo) y 37 por ciento en el recto. Se encontraron metástasis hepáticas sincrónicas en 16.8 por ciento, carcinomatosis perineal aislada en 5,4 por ciento y extensión del tumor a estructuras vecinas en 13,9 por ciento. 527 pacientes fueron operados (95,2 por ciento) con una mortalidad operatoria de 11,8 por ciento y el tumor fué resecado en 475 (tasa de resecabilidad de 86 por ciento) con una mortalidad posresección de 10,8 por ciento. El análisis de los datos obtenidos permite: 1) confirmar la adecuada metodología utilizada en el registro que asegura la exhaustividad de los datos obtenidos; 2) afirmar que los parámetros principales de la enfermedad no presentan diferencias sustantivas con los propios de series poblacionales no seleccionadas de los países desarrollados

Cáncer de vesícula / Gall-bladder cancer

El cáncer de vesícula es considerado una enfermedad, en general, incurable. Ultimamente ha sido posible obtener mejores resultados mediante el conocimiento de la evolución de la enfermedad y la capacidad de determinar subgrupos de pronóstico más favorable. El objetivo de este trabajo es tratar de determinar factores que influyan en la sobrevida a largo plazo. Para ello se realiza un análisis retrospectivo de los pacientes operados por cáncer de vesícula durante 10 años en un servicio de cirugía general. El sistema de clasificación utilizado fue el T.N.M. de la Unión Internacional Contra el Cáncer de 1987. El cáncer de vesícula constituyó 3 por ciento de 1500 colecistectomías, siendo la edad promedio de 59 años. La incidencia en las piezas de colecistectomía se incrementó con la edad: la edad promedio para el estadio I fue 58 años, para el II 62 años, para el III 64 años y para el IV 70 años. Se realizaron 26 colecistectomías simples, 6 colecistectomías radicales (hepatectomía medial y vaciamiento linfoganglionar del pedículo hepático, retroduodenopancreático y tronco celíaco), 3 colecistostomías, 2 intubaciones transtumorales y 9 laparotomías exploradoras. La morbilidad global fue 8 por ciento y la mortalidad 11 por ciento. Para la cirugía radical las cifras fueron de 30 por ciento y 0 respectivamente. La sobrevida de los pacientes sometidos a cirugía radical fue de 100 y 80 por ciento a 2 y 3 años respectivamente. No se dispuso de datos referentes al seguimiento de las colecistectomías. Como conclusión se establece que el pronóstico de los pacientes con cáncer de vesícula no es homogéneo, los tumores en estadios tempranos, con un grado alto de diferenciación, que generalmente se diagnostican en pacientes menores de 60 años se benefician de la cirugía radical y obtienen sobrevidas satisfactorias a largo plazo