NH not related to sleep-disordered breathing has been reported in patients with PAH. We describe the incidence of NH in PAH patients without parenchymal lung disease, and evaluate associated factors.
Patients who spent >10% of the total sleep time with an SpO2 <90% were considered nocturnal desaturators (Desat). Variables analyzed included: demographics, spirometry, hemodynamics, and 6-minute walk test (6MW). Unpaired Student’s t-test and Mann-Whitney rank sum test were used to compare variables between Desat and nondesat (ND).
Of the 38 patients (33 F/5 M; mean age: 47, range 18-71 yrs), 26 (68%) were Desat and 12 (32%) were ND. Patients in the Desat group spent 46±27% (mean±SD) of sleep time with SpO2 <90%. Desats were older (50±12 vs 40±14; p=0.02), had higher BMI (30±5 vs 27±3; p=0.07, had lower resting SpO2 (94±3.5 vs 97±2.4; p=0.01), lower FEV1% pred. (75±12 vs 85±13; p=0.03), and higher Hb level (14.4±1.7 vs 13±1.2; p=0.02) than ND. There was no statistically significant difference in terms of hemodynamics, 6MW distance, BNP, Borg, or TSH. In the Desat group 65% (17/26) did not require supplemental oxygen during their 6MW. Patients in the Desat group undergoing sleep studies were not found to have significant OSA.
A high prevalence of NH was seen among our group of patients with PAH. The severity of NH was significant given the time spent <90% and the elevated Hb levels. NH did not correlate with accepted indices of PAH severity or with O2 need during 6MW. The inclusion of overnight oximetry in the routine work-up of patients with PAH is warranted since other indices of PAH severity or oxygen need during 6MW may not accurately identify these patients.
Overnight oximetry should be a part of the routine work-up of patients with PAH since other indices of PAH severity or oxygen need during 6MW may not accurately identify patients with nocturnal hypoxia.
Chirag Pandya, None.