Use of SPECT to detect changes in diastolic and coronary reserve in patients with obstructive sleep apnea.
OBJECTIVE
To assess diastolic function and coronary artery reserve in patients with obstructive sleep apnea (OSA) using single-photon emission computer tomography (SPECT).


METHODS
Patients with OSA who had normal echocardiograph/electrocardiogram findings were divided into three groups based on OSA severity: mild (n = 15), moderate (n = 13), or severe (n = 18). A control group of participants without OSA (n = 17) was included. SPECT (with technetium-99 m-labeled red blood cells) was performed after the induction of cardiac stress by injection of dobutamine. The following ventricular parameters were determined: left ventricular ejection fraction, peak filling rate (PFR), peak ejection rate, 1/3 filling fraction (1/3FF), and regional ejection fractions (rEF).


RESULTS
The median ages of OSA and control participants were 45.0 and 51.0 years, respectively. Median apnea-hypopnea index scores were 3.3, 9.1, 38.5, and 65.2 for the control, mild OSA, moderate OSA, and severe OSA groups, respectively. Post-stress, 1/3FF was significantly lower in the overall OSA group compared with the control group (P < 0.05). PFR was significantly lower in the overall OSA group compared with the control group (P < 0.05) and was significantly lower in the severe OSA group compared with the mild OSA group. Regional ejection fractions rEF3 (cardiac apex and a small part of the inferior wall) and rEF4 (anteroseptal wall) were significantly lower in the overall OSA group compared with the control group, suggesting decreased coronary artery reserve.


CONCLUSIONS
Our findings suggest that SPECT can be used to detect abnormalities in diastolic function and coronary reserve in patients with OSA who have normal electrocardiogram or echocardiograph findings. SPECT may be useful for the early detection of cardiovascular disease in patients with OSA.
Sleep Disorders Breathing Diagnosis, and Treatment Center, Department of Respiratory Medicine, The Second Teaching Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, China. myemaily@sohu.com
Bei
B
Wang
Zhou-la
ZL
Liu
Bo
B
Niu
Hong-Wei
HW
Liang
Ren-Li
RL
Qiao
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D003971:Diastole / Q000502:physiology*; D004280:Dobutamine; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012016:Reference Values; D020181:Sleep Apnea, Obstructive / Q000145:classification / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D013318:Stroke Volume / Q000502:physiology; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D016277:Ventricular Function, Left / Q000502:physiology
D004280:Dobutamine