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Sindromul de apnee obstructivă de somn, funcția cardiacă și capacitatea de efort

Carmen C. Stroescu, Ștefan Dumitrache Rujinski, Ofelia Spinu, Ionela Erhan, Bianca Paraschiv, Irina Pele, Miron A. Bogdan
Sindromul de apnee obstructivă de somn, funcția cardiacă și capacitatea de efort

Background. Obstructive sleep apnea syndrome (OSAS) is a risk factor for cardiovascular (CV) diseases due to high intrathoracic pressure variations, intermittent hypoxemia and sympathetic activation. Few studies evaluated the peak/maximal exercise capacity (peakVO2) in patients with severe OSAS.

Aim. The evaluation of peakVO2 and its relation with cardiac morphology/function and indices of OSAS severity (the Apnea Hypopnea Index - AHI; the Oxygen Desaturation Index - ODI) in severe OSAS patients.

Method. PeakVO2 and cardiac morphology nd function (transthoracic echocardiography) were evaluated in severe OSAS patients without overt CV or respiratory comorbidities. The relationships between AHI, ODI, peakVO2 and echocardiographic parameters were assessed.

Results. The study included 25 patients (among them 6 women), with the following characteristics: age 45.2±1.9 years; BMI 34.8±1kg/m2; AHI 60±4.8 events/hour; ODI 47/hour (range 16.5-100); peakVO2/kg 19.76±0.95 ml/ min/kg. 21 patients had low peakVO2/kg (≤ 25ml/min/ kg). Nine out of seventeen patients had increased left atrial volume, and 13 had left ventricle (LV) diastolic dysfunction. Seven patients had low LV ejection fraction (LVEF<55%). PeakVO2/kg had a negative correlation with AHI (r= -0.536), ODI (r= -0.441), the left atrial volume (r=-0.632) and the right ventricle outflow tract (r=  -0.490).

Conclusion. We found a low peakVO2 in 84% severe OSAS patients with no clinical findings of heart failure. The exercise capacity correlated with both OSA severity and cardiac anomalies. The use of cardiopulmonary exercise test (CPET) allows the identification of subclinical cardiac dysfunction in severe OSAS patients.