Assessment of right atrium dysfunction in patients with obstructive sleep apnea syndrome using velocity vector imaging.
BACKGROUND AND OBJECTIVES
This study aimed to assess the changes of RA function in patients with obstructive sleep apnea syndrome (OSAS) using velocity vector imaging (VVI) and to evaluate the application of VVI technology.


METHODS
According to the apnea-hypopnea index (AHI), 71 patients with OSAS were divided into three groups: mild, moderate, and severe. A total of 30 cases of healthy subjects were enrolled as the control group. Digital images of apex four-chamber views were acquired to measure the right atrium (RA) linear dimensions and volume parameters including RA longitudinal diameter (RAL), transverse diameter (RAT), RA maximum volume (Vmax), RA minimum volume (Vmin), right atrial volume before contraction (Vpre). Right atrial volume parameters were corrected by body surface area (VImax, VImin, VIpre). The total right atrial emptying fraction (RATEF), right atrial passive emptying fraction (RAPEF), right atrial active contraction emptying fraction (RAAEF) were calculated. The VVI data measuring right atrial global strain (RA-GLS), right atrial strain rate in ventricular systolic phase (RA-SRs), right atrial strain rate in ventricular early diastolic phase (RA-SRe), right atrial strain rate in ventricular late diastolic phase (RA-SRa).


RESULTS
1. RA linear dimensions and volume parameters in severe OSAS were higher than those of control group. RAPEF in severe group was lower than control group and mild OSAS group (t = 2.681, P = 0.021; t = 2.985, P = 0.011; respectively). RAAEF in OSAS moderate group was higher than that of control group (t = 3.006, P = 0.02), and without statistical difference (P > 0.05) in the severe OSAS group and the control group. 2. RA-GLS in moderate OSAS group was significantly lower than that of control group (t = 2.333, P = 0.040) and reduced more obvious in the severe OSAS group (vs control, t = 3.25, P = 0.008, vs mild; t = 3.011, P = 0.012; respectively). RA-SRe in moderate and severe OSAS groups were lower than control group (t = 2.466, P = 0.031; t = 3.547, P = 0.005; respectively). RA-SRs of OSAS in severe group was lower than that of control and mild groups (t = 3.665, P = 0.004; t = 3.204, P = 0.008; respectively). RA-SRa in severe OSAS group was lower than that of control group (t = 2.425, P = 0.034). 3. Multivariate regression analysis showed that RA-GLS and RA-SRe were independently correlated with AHI (t = - 2.738, P = 0.010; t = - 2.191, P = 0.036; respectively).


CONCLUSION
RA function was impaired in patients with OSAS. On hemodynamics, the change of RA function performed increased of reserve function, reduced pipeline function and increased of contraction function. However, the strain and strain rate reduced in different degree. RA-GLS and RA-SRe decreased the earliest, which suggested that strain and strain rate were the parameters which can reflect myocardial function damage earliest. VVI can more earlier and accurately detect myocardial dysfunction of right atrium in patients with OSAS, which is expected to be a worthy technique for early clinical therapy in patients with OSAS.
['Li|Junfang|J|', 'Lu|Changhong|C|', 'Wang|Wugang|W|', 'Gong|Kun|K|', 'Zhao|Liang|L|', 'Wang|Zhibin|Z|http://orcid.org/0000-0003-4090-6360']
D000328:Adult D016280:Atrial Function, Right D016022:Case-Control Studies D004452:Echocardiography D005260:Female D006325:Heart Atria D006801:Humans D017078:Laser-Doppler Flowmetry D008297:Male D008875:Middle Aged D015999:Multivariate Analysis D017286:Polysomnography D012016:Reference Values D012044:Regression Analysis D012189:Retrospective Studies D018570:Risk Assessment D012720:Severity of Illness Index D020181:Sleep Apnea, Obstructive
Obstructive sleep apnea syndrome Velocity vector imaging Right atrial strain Right atrial function