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

Flutter auricular crónico: una manifestación infrecuente de enfermedad del nódulo sinusal: caso clínico / Chronic atrial flutter as an infrequent manifestation of sick sinus syndrome: report of 1 case

We report a 41 years old female, previously operated of an atrial septal defect, presenting with a persisting atrial flutter. Sinus node dysfunction became evident during an electrophysiological study at the moment of interrupting the flutter with electrical stimulation. The patient was treated with his bundle ablation and implantation of a definitive pacemaker. After one year of follow up, she is devoid of symptoms

Actividad de las metaloproteinasas en el miocardio de ratas sometidas a endotoxina y su inhibición con doxiciclina / Metalloproteinase activity in myocardium of rats exposed to endotoxin: its inhibition with doxycycline

Background: The ventricular dysfunction of endotoxic shock could be secondary to the activity of myocardial metalloproteinases that degrade collagenous matrix. Metalloproteinase activity can be inhibited with doxycycline in some tissues. Aim: To study if the effect of endotoxemia on myocardial metalloproteinase activity can be inhibited with doxycycline. Material and methods: Left ventricular metalloproteinase activity was studied in four groups of rats. Group 1 received intraperitoneal dextrose in water, group 2 received 8 mg/kg intraperitoneal E coli endotoxin, group 3 received 60 mg/kg/day doxycycline for three days and group 4 received doxycycline and E coli endotoxin. Enzymatic activity was measured by Western Blot and zymography. Results: Zymography showed a higher metalloproteinase 2 (49 percent) and 9 (100 percent) activity in rats treated with endotoxin, when compared with control rats. In group 4, doxycycline reduced the activity of metalloproteinases 2 and 9 by 71 percent and 63 percent respectively, as compared with group 3. Western blot showed a 50 percent increase in the expression of metalloproteinase 1 in rats treated with endotoxin, that was reduced by 64 percent with the use of doxycycline. Conclusions: Endotoxin administration increases myocardial metalloproteinases and doxycyclin inhibits this activation. Therefore, doxycyclin could reduce the degradation of myocardial fibrillar collagen and ventricular dysfunction of endotoxic shock

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

Validación de un método para realizar angiografía cuantitativa a bajo costo / Validation of a low cost method for quantitative angiography

La angiografía cuantitativa es el método de elección para la medición de la severidad de las lesiones coronarias en cardiología intervencional. Sin embargo, su aplicabilidad está restringida por los elevados costos de los programas comerciales que permiten realizar estas mediciones. En el presente trabajo hemos estudiado la posibilidad de desarrollar un sistema de angiografía cuantitativa a un costo más razonable, abordable por distintos laboratorios en el país. Diversos moldes de polietileno (PE,n=14) de diámetro interno conocido (entre 0, 58 y 1,67 mm) fueron llenados con medio de contraste y filmados con un cineangiógrafo General Electric a 25 cuadros por segundo. Los films fueron escaneados (Microteck) y las imágenes digitales fueron transferidas a un programa computacional de libre distribución (Image-NIH), con el cual se realizaron las mediciones en un computador Quadra, con una relación de 14 bit/pixel. También se realizaron aortografías de ratas Sprague Dawley anestesiadas (n=5), y los films fueron procesados de idéntica manera. Inmediatamente después de la aortografía, las ratas fueron perfundidas in vivo con formalina a 100 mm Hg, para mediciones histológicas posteriores. Se encontró una correlación de 0,95 (p<0,001) al comparar los valores reales de los diámetros de los moldes de PE versus los medidos digitalmente, y de 0,91 (p<0, 0001) para las áreas. La exactitud de la medición fue de 0,046 mm. Al comparar los diámetros de la aotiografía versus los diámetros histológicos, se encontró una correlación de 0,92 (p<0,02). Los díámetros reales fueron 1,06 ñ 0,1 mm y los medidos 1,09 ñ 0,07mm, lo cual representa una diferencia de 3,5 por ciento (NS). En conclusión, se logró validar un método de angiografía cuantitativa que requiere de elementos tecnológicos mínimos y de bajo costo. Este método puede ser de utilidad en laboratorios de hemodinamia que estén interesados en comenzar a realizar anaioarafía cuantitativa

Aterectomía rotacional (rotablator) en la angioplastía coronaria percutánea transluminal / Rotational atherectomy (rotablator) for percutaneous transluminal coronary angioplasty

Background: The use of Rotablator in percutaneous transluminal coronary angioplasty attempts to reduce the atheromatous plaque abrading it and fragmenting the pariental calcium of the artery. Aim: To report our experience with the use of Rotablator: Patients and methods: Rotational atherectomy was performed in 189 patients aged 60.8 ñ 11 years (154 men). The clinical indication for the procedure was chronic angina in 22 percent, unstable angina in 44 por ciento, myocardial infarction in 21 percent, silent angina in 7 percent and re-stenosis in 6 percent. One bundred seventy seven patiens were followed for a mean of 15.9 ñ 6.3 months. Results: Two hundred thirty six stenoses in 215 coronary arteries were treated with a 98.7 percent angiographic success rate. One patient had a Q infarction and no patient died or required emergency surgery. Fourteen patients had rises in CK MB enzymes (non Q infarction). Thee patients had a pseudoaneurism and three had bleedings that required transfusion. Of the followed patients, 33 had a clinically suspected re-stenosis, that was angiographically confirmed in 23. Cardiac mortality was 2.3 percent. Seventy nine percent of patients had an evolution without angina or coronary events. Conclusions: Percutaneous transluminal coronary angioplasty with the use of Rotablator had a high immediate success rate and a low incidence of complications. The clinical evolution of patients has been favorable with a low incidence of mortality and ischemic events

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

Hormonas vasodilatadoras en la insuficiencia cardíaca crónica: efecto de la inhibición de la enzima convertidora de angiotensina / Vasodilator hormones in chronic heart failure: effect of the inhibition of angiotensine converting enzyme

To evaluate the chronic effect of enalapril, in addition to digitalis and diuretics, in patients with chronic heart failure, nine patients with an idopathic dilated cardiomyopathy (8 males, aged 48 to 76 years old) under treatment with digitalis and diuretics, received enalapril 20 mg bid during eigth weeks. Before and after this treatment period resting left ventricular ejection fraction, functional class, plasma levels of atrial natriuretic factor and bradykinins (BK) and urinary excretion of kalikreins (BK) and prostaglandins E2 (PGE2) were measured. After enalapril therapy, there was a significant increase in maximal O2 consumption (14.8ñ1.2 to 18.6ñ1.5 ml/kg/min, p<0.05) and radionuclide LV ejection fraction (27.4ñ1.1 to 31.4ñ0.9 percent p<0.05). This was associated with a significant decrease in plasma ANP levels (559ñ158 to 178ñ54.8 pg/ml) and UK (391ñ112 to 243ñ92 Cu/24 h). The decrease in ANP levels, which is a well known marker of prognosis in CHF, could contribute to explain the sustained clinical benefits observed with ACE inhibitors in patients with CHF

Actividad de metaloproteinasas de arterias y venas y su regulación mediante doxiciclina / Metalloproteinase activity of arteries and veins and it regulation through doxycicline

Segments of internal mammary arteries and saphenous veins and cultured smooth muscle cells were incubated with and without doxycicline. Metalloproteinases activity was assessed by zymography and Western Blot. Activity of Metalloproteinase-9 in saphenous veins was 217 percent less than in internal mammary arteries. In these vessels doxycicline decreased metalloproteinase-9 activity by 207 percent and metalloproteinase-1 expression. In cultured smooth muscle cells, the median inhibitory concentration of doxycicline for metalloproteinase-2 was 138 uM (r2=0.82). Internal mammary arteries and saphenous veins have different metalloproteinase activities, that are inhibited by doxycicline

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

Reestenosis postangioplastía coronaria: ¿estrechamiento arterial o depósito de matriz extracelular? / Restenosis of coronary postangioplasty: arterial stenosis or deposit of extracellular matrix?

La angioplastía coronaria se realiza con una tasa de éxito y baja incidencia de complicaciones. Sin embrago, la reestenosis postangioplastía continúa siendo una limitante seria, que ocurre entre un 20 y un 50 por ciento de los enfermos. Las teorías actuales sobre la etiopatogenia de la reestenosis son dos: a) la reestenosis sería secundaria a una retracción o estrechamiento crónico de la arteria post procedimiento; b) ésta se debería al depósito de matriz extracelular, principalmente colágeno en la neoíntima. Nuestro grupo ha señalado que el aumento de colágeno en la neoíntima se debe tanto a un aumento de la síntesis como a una disminución de la degradación del colágeno. En esta revisión planteamos la hipótesis de que ambos mecanismos (estrechamiento del vaso y la acumulación de colágeno) podrían ser parte de un mismo fenómeno: una respuesta cicatricial de la arteria, que compromete todas sus paredes, iniciada por la injuria inherente al procedimiento, independiente de la técnica angioplástica utilizada. Se discuten lagunos problemas conceptuales en la definicón de reestenosis, el aporte de la ecografía intracoronaria en este campo y se plantean potenciales soluciones a este problema

Valvuloplastía mitral percutánea con técnica de Inoue: resultados de acuerdo al grado de alteración ecográfica / Percutaneous mitral valvuloplasty with Inoue technique: results according to the degree of echographic alterations

Hay cierta incertidumbre referente a las diferencias en resultados de acuerdo al grado de daño preexistente de la válvula mitral en pacientes sometidos a valvulotomía percutánea con el balón de Inoue. Analizamos nuestra serie consecutiva de 126 pacientes (88 por ciento mujeres) tratadas con este procedimiento desde abril de 1990 a diciembre de 1994. Todos los pacientes tuvieron un área valvular mitral (AVM, método de hemipresión por Doppler)< 1,5 cm² e insuficiencia mitral ausente o menor de grado 2/4. El mismo ecocardiografista determinó el AVM antes y 24 a 48 horas después del procedimiento. En 71 por ciento de los pacientes se efectuó una nueva medición del AVM 12 ñ 1 meses después de la valvuloplastía. La valvuloplastía falló en 5 pacientes: no se pudo cruzar la válvula mitral en 3, 1 paciente falleció durante el procedimiento y 2 tuvieron tamponamiento cardiaco tratado por cirugía de emergencia con comisurotomía quirúrgica en el mismo acto. En los 121 pacientes restantes (96 por ciento), la presión media de aurícula izquierda disminuyó de 20 ñ 6 (DS) a 11 ñ 5 mmHg (p <0,001) y el AVM aumentó de 0,96 ñ 0,16 a 1,80 ñ 0,33 cm² (p <0,001). Cuatro de los 5 casos fallidos tenían puntaje de Wilkins ò 10. En 99 pacientes con puntaje £ 7, el AVM aumentó 98 ñ 40 por ciento, en tanto que en 22 pacientes con puntaje de 8 ó 9 el AVM aumentó 79 ñ 41 por ciento (p <0,05). Tres pacientes entre los primeros y 1 entre los segundos desarrollaron insuficiencia mitral ò 3/4. Se observó una disminución leve del AVM en el control efectuado 1 año después de la valvuloplastía (1,83 ñ 0,27 a 1,73 ñ 0,29 cm²). Concluimos que la valvuloplastía mitral percutánea con el balón de Inoue es segura y efectiva en pacientes bien seleccionados (puntaje de Wilkins menor de 10). Los pacientes con puntaje > 7 tienen resultados menos favorables que aquellos con puntajes menores

Amrinona intravenosa en insuficiencia cardíaca refractaria: efectos clínicos, hemodinámicos y metabólicos / Amrinone in refractory congestive heart failure

En el presente trabajo se estudió si el beneficio de la infusión de Amrinona en pacientes con Insuficiencia Cardíaca Crónica Refractaria (ICCR) se relacionaba con modificación de la congestión visceral o de la perfusión tisular. Se estudiaron 10 pacientes (7 hombres, edad entre 52 y 77 años). La cardiopatía de base fue miocardiopatía dilatada idiopática en 7 pacientes, enfermedad coronaria en 1 y enfermedad reumática en 2 pacientes. El protocolo consistió en la infusión por 72 horas de Amrinona iv (promedio 10.2 ug/kg/min), además de diuréticos y digital. Se midieron antes e inmediatamente después de la administración de Amrinona diferentes parámetros: score clínico (SC), hemodinamia, dimensiones cardíacas (ECO 2D), índices de congestión visceral (peso corporal, congestión pulmonar radiológica y Volemia Plasmática), índices de perfusión tisular (ácido láctico arterial, clearance de creatinina y Flujo Plasmático Renal) y noradrenalina plasmática. Luego de la infusión de Amrinona mejoró el SC (12.8 ñ 0.5 vs 5.4 ñ 2.4, p < 0.009), y disminuyeron el peso (65.6 ñ 8.1 vs 63 ñ 9.5 kg, p < 0.05), Volemia Plasmática (2839 ñ 581 vs 2582 ñ 693 ml, p < 0.04) y la Presión Capilar Pulmonar (27.2 ñ 3.7 vs 17.9 ñ 7.0 p < 0.01). Aumentó el débito cardíaco (4.0 ñ 1.4 vs 5.1 ñ 2.1 lt/min, p < 0.05). No se observaron cambios significativos en el tamaño cardíaco, presión venosa central, resistencia vascular sistémica, flujo plasmático renal ni en noradrenalina plasmática. En estos pacientes, la terapia con Amrinona asociada a la terapia convensional, aumentó el gasto cardíaco, redujo la volemia y los parámetros de congestión visceral, lo que se asoció a mejoría clínica objetiva. Por otra parte, no observamos cambios significativos en los parámetros de perfusión tisular

Terapía combinada de propranolol y diltiazem en angina crónica de esfuerzo / Combined therapy with propranolol and diltiazem in with chronic exertional angina

The effects of diltiazem, 240 mg/day, were studied in 12 p atients with chronic exertional angina and angiographically proven coronary artery disease, who received maintenance therapy with propranolol. Mean age was 60,1 years (range 46 to 67). Patients received propranolol, 60 to 240 mg/day, before and during the study. A double blind, placebo contorlled, cross-over design was used to test the effect of added diltiazem, durign 8 weeks. Duration fo execise varied from 398 ñ 30 (mean ñ SEM) to 419 ñ 37 (placebo) or 469 ñ 35 sec (diltiazem) (NS). Time to appearance of angina veried from 283 ñ 32 to 313 ñ 34 and 302 - 27 sec, respectively (NS). Resting and maximal effort heart rate and blood pressure did not differ among basal, placebo and iltiazem conditions. Segmental wall motion analysis by radioisotopic ventriculogram revealed diskynetic zones during placebo rodiltiazem therapy. Basal ejection fraction did not increase during exercise and this was not modified by diltiazem or placebo. Thus, the addition of diltiazem to propanolol in patients with chronic, exertional angina failed to modify angina threshold, exercise duration or left ventricular performance