Use of SPECT to detect changes in diastolic and coronary reserve in patients with obstructive sleep apnea.

PURPOSE: 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. CONCLUSION: 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.

[A study on the endogenous cannabinoid system synthetic and catabolic enzyme levels in patients with obstructive sleep apnea].

OBJECTIVE: To observe the differences of endogenous cannabinoid system (ECS) synthetic and catabolic enzyme levels between the obstructive sleep apnea syndrome (OSA) patients and the control subjects. METHODS: Patients with OSA confirmed by PSG in our Sleep Center were randomly recruited from July to December, 2009. Peripheral blood was obtained to isolate mononuclear cells and the mRNA levels of anandamide (AEA) synthase N-acylphosphatidylethanolamine hydrolyzing phospholipase D (NAPE), fatty acid amide hydrolase (FAAH) and 2-arachidonoylglycerol (2-AG) synthase diacylglycerol lipase (DAGL) and hydrolase monoacylglycerol lipase (MAGL) were measured by real-time polymerase chain reaction. The association between the severity of OSA and the enzyme levels were explored. RESULTS: There was a significant difference in both the NAPE and MAGL levels between patients with OSA and the control subjects. The level of MAGL was related to some indices of severity of OSA, including the longest apnea time, lowest blood oxygen saturation and the micro-arousal index (r = 0.31, 0.24, 0.34, respectively, all P < 0.05). Compared with patients with OSA alone, patients with OSA complicated by hypertension showed a different level of FAAH (P < 0.05). CONCLUSION: OSA altered the expression of the ECS synthetic and catabolic enzymes, leading to an increase in endogenous cannabinoid substances.