The effects of dopamine and dobutamine on regional function in the presence of rigid coronary stenoses and subcritical impairments of reactive hyperemia

Abstract Intraluminal stenosing cylinders were inserted in the coronary arteries of open-chest, anesthetized dogs to assess the sensitivity of sympathomimetic infusion for detection of subcritical impairment of reactive hyperemia. Observations were made at rest and during steady-state infusions of dopamine and dobutamine (each 10 μg/kg/min) before and after placement of the cylinder. Each stenosis was associated with subcritical impairment of postocclusion reactive hyperemia at rest. The degree of impairment was used to stratify experiments into mild (group A) and moderate (group B) cohorts. In group A, reactive hyperemia was 217 ± 55 cc/min prior to cylinder placement and 82 ± 17 cc/min ( p p p = NS). Thus, with subcritical lesions in a single vessel, dobutamine infusion was associated with depressed regional function when reactive hyperemia was impaired by more than 80%.