Hyperoxia and Microvascular Dysfunction

Summary

Coronary artery disease (CAD) pathophysiology involves endothelium-dependent (e.g. nitric oxide, acetylcholine) and -independent (e.g. adenosine) vascular dilation impairment, which have been demonstrated at the level of small coronary arteries, medium sized peripheral arteries and subcutaneous microcirculation. Oxygen supplementation, which is frequently overused in clinical settings, seems harmful in acute coronary syndromes and increases microvascular resistance in myocardial and subcutaneous microcirculation through alteration of endothelium-dependent and -independent dilation by an oxidative mechanism. Whether endothelial dysfunction, that is well documented at the level of cardiac microcirculation in CAD patients, is also present at the level of subcutaneous microcirculation is unknown. Also, unknown is whether an acute oxidative stress can be used to probe myocardial microcirculatory dysfunction at the level of subcutaneous microcirculation, which is an easily accessible vascular bed for an in vivo assessment of endothelial-dependent and-independent function. Alterations in cutaneous vascular signalling are evident early in the disease processes. Thus, studying subcutaneous circulation in patients with cardiovascular risk factors could provide vascular information early in CAD processes. This study will test the following 4 hypotheses:

1. Endothelial dysfunction observed at the level of microvascular cardiac arteries is readily present at the level of subcutaneous microcirculation in a given CAD patient.
2. An acute oxidative stress such as hyperoxia can be used to test myocardial microcirculatory dysfunction at the level of the more easily accessible subcutaneous microcirculation.
3. Subcutaneous microcirculation of CAD patients has a lesser vasodilatory response to acetylcholine or sodium nipride than matched healthy subjects. In addition, CAD patients are more prone to dermal vasoconstriction in response to oxygen compared to healthy subjects.
4. Taken that oxygen is still too often given in excess in most clinical settings, the aim of this study is to rule out possible pitfalls in coronary pressure and resistance determinations in CAD patients receiving unnecessary oxygen supplementation.

Conditions

• Coronary Microvascular Disease
• Microvascular Disease
• Ischemic Heart Disease

Interventions

OTHER

Hyperoxia

OTHER

Normoxia

DEVICE

laser Doppler

laser Doppler

Sponsors & Collaborators

• Université Libre de Bruxelles

  lead OTHER

Principal Investigators

• Jean-Paul Van Vooren, MD, PhD · Hospital Erasme

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

85 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2016-12-01

Primary Completion

2018-04-01

Completion

2018-10-01

Countries

• Belgium

Study Locations