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Aumento de la constricción alfa-adrenérgica de las arterias coronarias humanas ateroscleróticas
1Departments of Cardiology and Pathophysiology (G.H.), Center of Internal Medicine, University of Essen, Germany. dbaum3@t-online.de
Circulation
|April 27, 1999
Resumen
La activación adrenérgica alfa-1 no afecta el flujo sanguíneo coronario en las arterias sanas, pero la activación alfa-2 causa constricción. La aterosclerosis exacerba estos efectos, induciendo potencialmente una isquemia miocárdica.
Área de la Ciencia:
- Cardiología Cardiología.
- Farmacología Farmacología.
- Fisiología Fisiología Fisiología.
Sus antecedentes:
- La activación adrenérgica está implicada en la isquemia miocárdica experimental.
- El papel de la constricción coronaria alfa-adrenérgica en los seres humanos sigue sin estar claro.
- Este estudio investiga la activación selectiva del receptor alfa-adrenérgico en las arterias coronarias humanas.
Objetivo del estudio:
- Evaluar el impacto de la activación selectiva de los receptores alfa1- y alfa2-adrenérgicos en el flujo sanguíneo coronario (FCB) en humanos.
- Para determinar si la aterosclerosis coronaria afecta la respuesta a los agonistas alfa-adrenérgicos.
- Evaluar el potencial de la activación alfa-adrenérgica para inducir isquemia miocárdica.
Principales métodos:
- El flujo sanguíneo coronario (FCB) se midió utilizando angiografía combinada y Doppler en 39 pacientes.
- Se administraron alfa1-agonistas selectivos (metoxamina) y alfa2-agonistas (BHT933) en dosis incrementales.
- Se evaluó la producción de lactato miocárdico en pacientes con estenosis de una sola arteria coronaria.
Principales resultados:
- La activación alfa1-adrenérgica no alteró la CBF en las arterias coronarias normales.
- Tanto la activación alfa1- como la alfa2-adrenérgica dependiendo de la dosis redujeron la CBF en pacientes con estenosis de la arteria coronaria.
- La activación alfa2-adrenérgica condujo a una mayor producción neta de lactato, lo que indica un aumento de la isquemia miocárdica.
Conclusiones:
- La activación alfa2-adrenérgica causa constricción microvascular en las arterias coronarias normales.
- Las constricciones inducidas por la activación alfa1- y alfa2-adrenérgica son amplificadas por la aterosclerosis.
- Estos efectos pueden precipitar la isquemia miocárdica en pacientes con enfermedad arterial coronaria.
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