Obstructive sleep apnoea is associated with residual pulmonary hypertension following pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension

<bold>Objectives:</bold> We have recently demonstrated that 80% of patients with chronic thromboembolic pulmonary hypertension(CTEPH) had sleep-related breathing disorders (SBDs),mainly obstructive sleep apnoea OSA,(defined as apnoea-hypopnoea index [AHI] ≥15 events/h) followed by isolated sleep-related hypoxemia (ISRH). In this study, we addressed the distribution of the SBDs as well as predictors of residual PH after pulmonary endarterectomy(PEA) in the same cohort. <bold>Methods:</bold> A new overnight polysomnography, as well as echocardiography, was conducted in 24 patients with CTEPH 112±65 days following the PEA according to the clinical routines. The peak tricuspid regurgitation velocity(TRV),with a threshold of >2.8 m/s, was applied for the assessment of the probability of residual PH. Retrospective evaluation were made. <bold>Results:</bold> The peak TRV decreased significantly in the entire cohort from 3.7±0.9 to 2.5±0.9 m/s (p<0.001). Six patients who had ISRH at baseline had either resolved(n=2) or converted to OSA (n=4). Fourteen of the 16 patients with OSA remained in the same category after PEA. Residual PH was observed in 13 patients (54.2%; all with OSA vs none with no-SDB; p= 0.003). In a multivariate analysis, AHI (odds ratio 1.19; 95% confidence interval 1.02-1.38, p=0.025)was associated with residual PH,adjusted for age, sex, body-mass-index and baseline mean pulmonary arterial pressure on right-heart catheterization. <bold>Conclusions:</bold> PEA is effective in improving PH and ISRH in patients with CTEPH. However, the residual PH is high and independently associated with OSA severity. Early diagnosis and treatment of OSA may reduce the risk of residual PH in CTEPH.