Coronariografía no invasiva mediante tomografía axial computada multicorte / 16 detector computed tomagraphy for coronary angiography

Antecedentes: La tomografía axial computada de 16 detectores de las arterias coronarias (TAC Coronario) ha emergido recientemente como una alternativa diagnóstica a la coronariografía invasiva (CI). Objetivo: Estudiar la exactitud del TAC coronario de 16 detectores para pesquisar la presencia o ausencia de estenosis coronaria en distintos tipos de pacientes, mediante su comparación con la CI. Métodos: A un total de 55 pacientes (46 hombres, 9 mujeres, promedio 57 +/-12 años) en quienes se realizó una CI electiva, se les realizó un TAC coronario. Se analizó específicamente la presencia de lesiones 50 por ciento y se compararon estos resultados con los obtenidos mediante la CI cuantitativa. Resultados: Cincuenta pacientes requirieron beta bloqueo, obteniéndose una FC promedio de 57 lpm. En los segmentos principales se objetivaron 61 lesiones significativas por CI, de las cuales 52 (85,2 por ciento) fueron correctamente detectadas por el TAC coronario. La sensibilidad, especificidad, LH(+) y LH(-) del examen fueron 85 por ciento, 97 por ciento, 33 y 0.15, respectivamente. La presencia o ausencia de enfermedad coronaria significativa fue correctamente diagnosticada en 50 de los 55 pacientes (91 por ciento). Conclusión: El TAC coronario de 16 detectores es un examen sensible y específico para el diagnóstico de estenosis significativas de los segmentos principales del árbol coronario.

Background: Invasive coronary arteriography (ICA) is the gold standard to assess coronary artery stenosis. Sixteen detector computed tomography (Coronary CT) has recently been introduced as a less invasive diagnostic alternative. Aim: To assess the reliability of Coronary CT in detecting coronary stenosis among different types of patients by comparing the results with those obtained by ICA. Methods: 55 patients (age 57+/-12 years, 46 males) who underwent ICA had also a coronary CT. Beta blockade was used to obtain a heart rate < 65 beats per min. The presence of significant stenosis (•'3d50 percent of luminal diameter measured by quantitative angiography) was compared between methods.Results: Adequate coronary images were obtained in 53 of 55 patients with coronary CT; a total of 715 coronary segments were available for analysis. Fifty patients required beta blockade and the mean heart rate was 57 beats per min. Fifty-two out of 61 main segment stenosis were detected by coronary CT (85.2 percent). Sensitivity, specificity, LH+ and LH- of coronary CT were 85 percent, 97 percent, 33 and 0.15, respectively. The presence or absence of significant lesions was correctly diagnosed in 50 of the 55 patients (91 percent). Conclusion: 16 detector coronary CT is a sensitive and specific method to diagnose main segment significant coronary stenosis.

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

Fulguración por radiofrecuencia de haces paraespecíficos / Fulguration by radiofrecuency of paraspecific bundles

Between august 1991 and august 1993, 75 patients (42 male) with Wolff Parkinson White syndrome (43 concealed) were subjected to radiofrequency ablation of accesory pathway at our institution. 55 had left, 8 postero septal, 2 anteroseptal and 10 right accesory pathways. A retrograde aortic technique with placement of the ablation catheter in close proximity to the mitral annulus was used for most of the patients with left accesory pathways and for some with posteroseptal pathways were ablated using a right heart approach placing the ablation catheter in the tricuspid annulus. Ablation was successful in 61 patients (81 per cent ). One subject developed a fatal cardiac tamponade after a transeptal catheterization and was unrelated to the ablation per se. It is concluded that radiofrequency ablation of accesory pathways is a curative procedure for a great majority of patients with Wolf Parkinson White syndrome

Disección coronaria espontánea en una mujer joven con infarto del miocardio: caso clínico / Spontaneous coronary dissection in a young woman with myocardial infarction: clinical case

Spontaneous coronary artery dissection in the absence of atherosclerosis, is a rare cause of acute myocardial infarction. We report a 37 years old woman with an inferior wall acute myocardial infarction secondary to an spontaneous dissection of the right coronary artery. The patient`s evolution was uneventful and a new angiography performed six months later showed that the dissection persisted. The possible etiologies and treatment are discussed