SESSION TITLE: Sleep Disorders Posters II: Consequences of OSA and Treatment
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM
PURPOSE: Chronic intermittent hypoxia (CIH) is thought to be the main component linking obstructive sleep apnea (OSA) to cardiovascular disease (CVD) and this was demonstrated in models of CIH that varied in both the frequency and severity of the hypoxic stimulus. Little is known how these findings impact cardiac performance. We therefore aimed to examine the impact of CIH on hemodynamic parameters in OSA patients with CVD.
METHODS: Consecutive patients without history of OSA who underwent CR after coronary re-vascularization between January 2012 to December 2012 in Roanoke and Harrisonburg, VA were subsequently diagnosed with OSA after at-home polysomnography. Hemodynamic measurements at rest were obtained using the impedance cardiograph. Normality of continuous variables was evaluated by Shapiro-Wilk test. Comparisons of continuous values between groups were performed using t test for data with normal distribution or Wilcoxon rank test, if skewed distribution. Linear regression was used to assess the relationship with cardiac variables (Cardiac Output, Cardiac Index, Ejection Fraction, Stroke Volume and left ventricular ejection time) and CIH (lowest oxygen desaturation and amount and percentage of time spent at an oxygen saturation less than 88%). A two-sided p value of <0.05 was considered statistically significanct.
RESULTS: Subjects groups did not differ by age, body mass index, blood pressure, heart rate, Apnea/Hypopnea Index (AHI), nocturnal desaturations or functional capacity. Time (0.02, CI = -6 to -0.5) and percentage of time spent at an oxygen saturation less than 88% (p= 0.01, CI = .37 to 1.29) correlated significantly with post-CR left ventricular ejection time (LVET). The change in pre-post LVET correlated with time (0.02, CI = 0.6 to 0.2) and percentage of time (p=0.04, CI = 1.7 to 0.8) spent at an oxygen saturation less than 88% as well.
CONCLUSIONS: One of the mechanisms by which CIH impairs cardiac function in OSA patients could be related to LVET.
CLINICAL IMPLICATIONS: Left ventricular ejection time should be considered as a surrogate of cardiac ischemia in patients with nocturnal desaturations related to OSA.
DISCLOSURE: The following authors have nothing to disclose: Faisal Siddiqui, Madalina Macrea, Mitchell Horowitz, Thomas Martin, Tomer Pelleg, Adrian Aron
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