CONDUCTA POSTERIOR AL INFARTO DE MIOCARDIO

Los pacientes con isquemia miocárdica espontánea o provocada en los días o semanas que siguen a un IAM, independientemente de si recibieron o no terapia fibrinolítica, deben someterse a una evaluación angiográfica coronaria electiva con subsecuente consideración de revascularización percutánea o quirúrgica. Existe, como en el caso de los pacientes con angina inestable, una considerable variabilidad en el empleo de la cinecoronariografía e intervención por catéter en los pacientes con IAM no complicado y con función ventricular normal. Aunque algunos centros practican rutinariamente la angiografía y angioplastía coronarias en los días que siguen al IAM en prácticamente todos los pacientes, los datos disponibles sugieren que tal estrategia de manejo no salva miocardio ni reduce la incidencia de infarto o muerte. La intervención rutinaria por catéter no otorga beneficios en ausencia de isquemia espontánea o inducible en las horas, días o semanas que siguen a un IAM tratado con trombolisis, esté el vaso permeable o no. Por el contrario, en el período agudo se asocia con una incidencia mayor de complicaciones, incluyendo hemorragia, ACV y cirugía de revascularización de urgencia.

En definitiva, la coronariografía y subsecuente revascularización deberían ser reservadas para sobrevivientes de IAM que tienen isquemia espontánea o inducible.

Indicaciones para angiografía y posible angioplastía coronaria según guías ACC/AHA Clase I

1. Pacientes con episodios isquémicos espontáneos o provocados por mínimos esfuerzos durante la convalecencia de un IAM.

2. Previo a tratamiento definitivo de una complicación mecánica del IAM, como insuficiencia mitral aguda, comunicación interventricular, pseudoaneurisma o aneurisma del ventrículo izquierdo.

3. Pacientes con inestabilidad hemodinámica persistente. Clase IIa

1. Frente a sospecha de etiología no trombótica del IAM, como embolismo coronario, algunas discrasias hematológicas (ej.: síndrome antifosfolipídico) o metabólicas, o espasmo coronario.

2. Sobrevivientes de IAM con función sistólica ventricular izquierda deprimida (≤ 40 %), insuficiencia cardíaca, revascularización previa o arritmias malignas.

3. Sobrevivientes de IAM con insuficiencia cardíaca inicial pero subsecuente función ventricular izquierda preservada.

Clase IIb

1. Angiografía rutinaria en todos los pacientes con IAM para detectar arterias ocluidas persistentemente en un intento de revascularizarlas, o identificar pacientes con enfermedad de tres vasos.

2. Todos los pacientes con IMSEST.

3. Recurrencia de taquicardia o fibrilación ventricular en pacientes sin evidencia de isquemia continuada.

Clase III

1. Angiografía y subsecuente angioplastia transluminal coronaria rutinarias de la arteria responsable del infarto, días después de terapia trombolítica.

EL FUTURO

El futuro real para el IAM no estará quizás en las estrategias de reperfusión, porque aunque ellas se hagan más y más efectivas, siempre habrá pasado un tiempo crítico entre el inicio de los síntomas y la restauración del flujo coronario. El verdadero beneficio estará, sin dudas, en la prevención del evento vascular. Las drogas inhibidoras de la HMG Co-A reductasa han demostrado prevenir eventos coronarios; y con una estrategia más agresiva de uso de las drogas hipolipemiantes y una mayor aceptación de dietas pobres en grasas aún podrá lograrse una mejor prevención del IAM. A pesar de ello, continuará habiendo pacientes que padezcan un IAM pese al uso de estatinas, aspirina, β bloqueantes y posiblemente IECA. Para estos pacientes, probablemente ocupen un lugar prominente las drogas que promuevan la “pasivización” de la placa ateroesclerosa, inhibiendo las metaloproteinasas, enzimas involucradas en la fisura de la misma. Si bien algunas herramientas innovadoras como el poder detectar a las “placas activas” por imágenes intravasculares y la posibilidad de “tapizar” el segmento coronario enfermo con polímeros biodegradables y sistemas de liberación local de drogas transferidas por genes, parecen todavía alejadas, es indudable que podrán ser diseñadas en un futuro cercano. Con el más amplio conocimiento actual de las causas y mecanismos que “inestabilizan” a las placas, se está en la actualidad en mejor posición para reducir sus complicaciones.

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