Effect of Mitral Valve Surgery on Overnight Fluid Shift and Sleep Apnea in Patients With Moderate to Severe Mitral Valve Regurgitation and Preserved Ejection Fraction

Abstract

SESSION TITLE: Sleep 2 SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, November 1, 2017 at 01:30 PM - 02:30 PM PURPOSE: Rostral fluid shift from the legs is strongly associated with sleep apnea (SA) in heart failure (HF) patients with reduced left ventricular ejection fraction (LVEF) accompanied by pulmonary congestion and/or pharyngeal edema. It is also known that sleep apnea is common among patients for cardiac surgery. Recent report showed that rheumatic valvular heart disease patients with obstructive SA had an increased incidence of perioperative complications, however the etiologies are unknown. Since MR contributes to pulmonary congestion and often have fluid retention in their legs, overnight fluid shift from the legs to the lungs or peripharyngeal area may play important roles in the pathogenesis of SA in patients with MR. Therefore, elucidating the relationship between fluid shift, SA, and effect of mitral valve (MV) surgery in patients with MR may provide some solutions. Purpose of this study is to investigate whether relationship between overnight fluid shit and severity of SA exists, and whether MV surgery affects either severity of SA and/or fluid shift, in patients with moderate-to-severe MR and preserved LVEF. METHODS: Patients with moderate-to-severe MR and preserved LVEF performed overnight polysomnography before and after the MV surgery. At the same time, leg fluid volume (LFV) was measured by bio-electrical impedance device before and after polysomnography. Relationship between overnight changes (△) of LFV and severity of SA as assessed by apnea-hypopnea index (AHI) was analyzed. RESULTS: Among 20 patients (mean age; 67±11 years, mean LVEF; 66±11%) enrolled, significant inverse relationship between △LFV and the AHI in univariable analysis (r=-0.78; P<0.001) was observed. Even in the multivariable regression analysis including other correlates to the AHI which showed P<0.1 in the univariable analyses, such as 24-hour urine volume (r=-0.46; P=0.041), regurgitant volume by PISA (r=0.46; P=0.049), use of diuretics (r=0.47; P=0.035) and beta blockers (r=054; P=0.014), △LFV was the significant correlates to the AHI (r=-0.72; P<0.001). 17 patients among them have done polysomnography after the surgery. Although body weight significantly decreased from 59.4±13.5 to 58.9±13.0 kg (P=0.004) following MV surgery, the AHI and △LFV did not change (AHI, from 27.9±18.5 to 31.4±18.0; P=0.463 and △LFV, from -397±188 to -401±202 ml; P=0.723). However, there were significant correlation between change in the AHI and change in △LFV, even after adjustment of change in the body weight (r=-0.58; P=0.035). CONCLUSIONS: Significant independent relationship between overnight fluid shift and SA severity were found in patients with moderate-to-severe MR and preserved LVEF. Despite no changes in AHI and LFV following MV surgery, there was a significant correlation between change in the AHI and change in △LFV. CLINICAL IMPLICATIONS: These findings suggest that in patients with moderate-to-severe MR and preserved LVEF, overnight rostral fluid displacement from the legs contributes to the pathogenesis of SA. Further investigation may contribute to reveal mechanisms. DISCLOSURE: Takatoshi Kasai: Grant monies (from industry related sources): affiliated with a department endowed by Philips Respironics, ResMed, and Fukuda Denshi The following authors have nothing to disclose: Azusa Murata, Shoichiro Yatsu, Hiroki Matsumoto, Takao Kato, Shoko Suda, Masaru Hiki, Kan Kajimoto, Taira Yamamoto, Atsushi Amano No Product/Research Disclosure Information