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Exaggerated renal vasoconstriction during exercise in heart failure patients.
Middlekauff, H R; Nitzsche, E U; Hoh, C K; Hamilton, M A; Fonarow, G C; Hage, A; Moriguchi, J D.
  • Middlekauff HR; Division of Cardiology, Department of Medicine, UCLA School of Medicine, Los Angeles, CA 90095, USA.
Circulation ; 101(7): 784-9, 2000 Feb 22.
Article en En | MEDLINE | ID: mdl-10683353
ABSTRACT

BACKGROUND:

During static exercise in normal healthy humans, reflex renal cortical vasoconstriction occurs. Muscle metaboreceptors contribute importantly to this reflex renal vasoconstriction. In patients with heart failure, in whom renal vascular tone is already increased at rest, it is unknown whether there is further reflex renal vasoconstriction during exercise. METHODS AND

RESULTS:

Thirty-nine heart failure patients (NYHA functional class III and IV) and 38 age-matched control subjects (controls) were studied. Renal blood flow was measured by dynamic positron emission tomography. Graded handgrip exercise and post-handgrip ischemic arrest were used to clarify the reflex mechanisms involved. During sustained handgrip (30% maximum voluntary contraction), peak renal vasoconstriction was significantly increased in heart failure patients compared with controls (70+/-13 versus 42+/-1 U, P=0.02). Renal vasoconstriction returned to baseline in normal humans by 2 to 5 minutes but remained significantly increased in heart failure patients at 2 to 5 minutes and had returned to baseline at 20 minutes. In contrast, during post-handgrip circulatory arrest, which isolates muscle metaboreceptors, peak renal vasoconstriction was not greater in heart failure patients than in normal controls. In fact, the increase in renal vasoconstriction was blunted in heart failure patients compared with controls (20+/-5 versus 30+/-2 U, P=0.05).

CONCLUSIONS:

During sustained handgrip exercise in heart failure, both the magnitude and duration of reflex renal vasoconstriction are exaggerated in heart failure patients compared with normal healthy humans. The contribution of the muscle metaboreceptors to reflex renal vasoconstriction is blunted in heart failure patients compared with normal controls.
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Banco de datos: MEDLINE Asunto principal: Circulación Renal / Vasoconstricción / Gasto Cardíaco Bajo / Ejercicio Físico Límite: Adult / Aged / Humans / Middle aged Idioma: En Año: 2000 Tipo del documento: Article
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Banco de datos: MEDLINE Asunto principal: Circulación Renal / Vasoconstricción / Gasto Cardíaco Bajo / Ejercicio Físico Límite: Adult / Aged / Humans / Middle aged Idioma: En Año: 2000 Tipo del documento: Article