Lower extremity edema and pulmonary hypertension in morbidly obese patients with obstructive sleep apnea.
BACKGROUND
In 70 consecutive male patients with obstructive sleep apnea (OSA) diagnosed at the Northport VA Medical Center Sleep Disorders Center, we have characterized the association between obesity, OSA, and pulmonary hypertension (PH).


METHODS
By including anthropometric, pulmonary function, and sleep study parameters in a multivariate logistic regression model, we found that a BMI of >40 kg/m(2) and the minimum oxygen saturation in non-rapid eye movement (NREM) sleep predicted the presence of pretibial edema in this sleep apnea population. We then characterized the hemodynamics of those OSA patients that had lower extremity edema. Twenty-nine of the 70 consecutive patients with sleep apnea (41%) had pretibial edema, and right heart catheterization data was obtained for 28 (97%) of these patients.


CONCLUSIONS
Ninety-three percent (26/28) of the patients had right heart failure (mean RAP > 5 mm Hg; RAP range = 0-32 mmHg) and PH (PA mean >or= 20 mm Hg) was present in 86% (24/28.) The OSA patients with lower extremity edema had an increased cardiac output (7.0 + 1.4 l/min) with a normal cardiac index (2.9 + 0.5 l/min/m(2)) in the setting of an elevated pulmonary capillary wedge pressure (PCWP 17 +/- 7 mmHg) and a normal pulmonary vascular resistance (122 + 70 dynes s cm(-5)). While PCWP, FEV(1)% predicted, and the minimum oxygen saturation in NREM sleep all independently predicted PH, PCWP was the most important predictor of PH.


CONCLUSIONS
We conclude that pulmonary hypertension is commonly seen in patients with OSA with pretibial edema and that pretibial edema is a highly specific sign of PH in OSA patients. Pulmonary hypertension appears to result from an elevated back pressure and diastolic dysfunction with contributions from lung function and nocturnal oxygen saturation.
O'Hearn
Daniel J
DJ
Department of Medicine, Portland VA Medical Center, Oregon Health & Science University, Portland, OR 97239, USA. ohearnd@ohsu.edu
Gold
Avram R
AR
Gold
Morris S
MS
Diggs
Paul
P
Scharf
Steven M
SM
D000328:Adult; D000368:Aged; D015897:Comorbidity; D004487:Edema / Q000453:epidemiology* / Q000503:physiopathology*; D006333:Heart Failure / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000453:epidemiology*; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010108:Oxyhemoglobins / Q000502:physiology; D010994:Pleura / Q000503:physiopathology; D011446:Prospective Studies; D011669:Pulmonary Wedge Pressure; D015635:Radionuclide Ventriculography; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology*; D012894:Sleep Stages / Q000502:physiology; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging
D010108:Oxyhemoglobins