Cardiovascular disease risk in patients with obstructive sleep apnea (OSA) may be predicted by evaluating myocardial blood flow and coronary flow reserve with 13N-Ammonia positron emission tomography/computed tomography (PET/CT) imaging, according to research from China presented in June at the annual meeting of the Society of Nuclear Medicine and Molecular Imaging in Anaheim, CA. The study findings suggest that patients with OSA should promptly undergo PET myocardial perfusion imaging to exclude coronary microcirculatory dysfunction.1
Left grouping: Mild OSA in a 38-year-old male, untreated. Center: Moderate OSA in a 49-year-old male, untreated. Right: Severe OSA in a 63-year-old male, untreated. Image courtesy SNMMI.
An estimated 1 billion individuals worldwide have OSA.2 Moreover, OSA is increasingly being recognized as a cardiovascular disease risk factor, explained lead author Ruonan Wang, MD, of the department of nuclear medicine of the First Hospital of Shanxi Medical University in Taiyuan. Impaired coronary flow reserve is an early sign of atherosclerosis.
Dr. Wang and his colleagues enrolled 38 patients with OSA who underwent stress/rest 13N-ammonia PET/CT scans. Quantitative PET/CT software automatically calculated myocardial blood flow and coronary flow reserve.
The patient cohort, consisting of 33 men and five women with a mean age of 42 years, was subdivided into mild, moderate, and severe OSA based on an apnea-hypopnea index. The majority of patients (15) had severe cases; 14 had mild cases, and 8 had moderate cases.
Dr. Wang reported that the mean rest myocardial blood flow was similar among all three groups. Although the mean hyperemic myocardial blood flow was also similar, the researchers determined that blood flow decreased gradually as the severity of OSA increased. There also were significant differences in the mean coronary flow reserve among the three groups, with the lowest coronary flow reserve occurring in the severe patient group.
SNMMI 2019: Using PET/CT to detect cardiovascular disease risk factors in sleep apnea patients. Appl Radiol.