A Prevalence Study of Obstructive Sleep Apnea in Subjects With Chest Pain, Positive Exercise Treadmill Test and Normal Coronary Angiogram

The University of Hong Kong20 enrolled

Overview

Cardiac syndrome X consists of a triad of chest pain, abnormal exercise stress testing and normal coronary angiogram, and is hypothesized to be related to endothelial dysfunction. Endothelial dysfunction is also reported to be linked to obstructive sleep apnea. While chest pain can be one of potential presenting symptoms of obstructive sleep apnea, the investigators hypothesize that obstructive sleep apnea is common in subjects with cardiac syndrome X.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Obstructive Sleep Apnea Cardiac Syndrome X Endothelial Dysfunction

Interventions

no intervention is involved in this studyOTHER

no intervention is involved in this study

Eligibility

Sex: ALLMin age: 18 YearsMax age: 70 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Age ≧18 years, \< 70 years * Symptom of chest pain occurring at least once in the preceding year * Positive exercise treadmill test * Negative coronary angiogram * Mentally fit to give informed consent Exclusion Criteria: * Mentally incapacitated persons * Congestive heart failure * Other potential causes of orthopnea (severe chronic obstructive pulmonary disease, persistent asthma)

Outcomes

Primary Outcomes

apnea hypopnea index

assess apnea hypopnea index by overnight polysomnography, by a single admission to sleep laboratory

Time frame: measure at a single time point when the subjects are admitted for overnight polysomnography

Secondary Outcomes

endothelial function

assess endothelial function by EndoPAT 2000 (an non-invasive device) and peripheral blood endothelial progenitor cells

Time frame: measured at a single time point when the subjects are admitted for overnight polysomnography