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Assessment of Vascular Tone Responsiveness using Isolated Mesenteric Arteries with a Focus on Modulation by Perivascular Adipose Tissues
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Assessment of Vascular Tone Responsiveness using Isolated Mesenteric Arteries with a Focus on Modulation by Perivascular Adipose Tissues

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Impaired peripheral vasoconstriction in response to alpha-adrenergic stimulation in patients with idiopathic

S Kawano1, K Iida, I Nishi

  • 1Department of Internal Medicine, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.

Japanese Circulation Journal
|January 16, 1999
PubMed

Insights

Patients with hypertrophic cardiomyopathy (HCM) show impaired vasoconstriction due to abnormal alpha-adrenergic receptor function. This finding helps explain exercise hypotension in HCM patients.

Area of Science:

  • Cardiology
  • Vascular Physiology

Background:

  • Exercise hypotension is observed in hypertrophic cardiomyopathy (HCM) patients.
  • This may stem from inadequate systemic vascular resistance increases during or post-exercise.

Purpose of the Study:

  • To investigate the pathogenesis of limb vascular response abnormalities in idiopathic HCM patients.
  • To assess peripheral vascular resistance regulation in HCM.

Main Methods:

  • Intra-arterial infusions of acetylcholine, nitroglycerin, phenylephrine, and isoproterenol in 13 HCM patients and 9 controls.
  • Forearm plethysmography to measure peripheral vascular resistance changes at rest and during infusions.

Main Results:

  • Isoproterenol, acetylcholine, and nitroglycerin caused similar dose-related vasodilation in both groups.
  • Phenylephrine infusions resulted in significantly lower percentage increases in vascular resistance in HCM patients compared to controls.
  • Alpha-adrenergic mediated vasoconstriction was impaired in HCM patients' peripheral vasculature.

Conclusions:

  • Peripheral vasoconstriction mediated by alpha-adrenergic receptors is impaired in patients with idiopathic HCM.
  • This impairment may contribute to exercise hypotension in HCM.

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