Long-term Effect of OSA and CPAP Treatment on Blood Pressure in Patients with Acute Coronary Syndrome

Obstructive sleep apnea (OSA) is prevalent in acute coronary syndrome (ACS) patients and is a cause of secondary hypertension.To explore the long-term effects of OSA and CPAP treatment on blood pressure (BP) in ACS patients.Post-hoc analysis of the ISAACC study included 1803 patients admitted for ACS (NCT01335087). Patients with OSA (apnea-hypopnea index (AHI) ≥15 events/h) were randomly assigned to receive either CPAP or/and usual care and followed up for one to 5 years. Office BP was determined at each visit.We included 596 patients without OSA, 978 patients in the usual care/poor CPAP adherence group and 229 patients in the good CPAP adherence group. At baseline, 52% of the patients were diagnosed with hypertension. Median age and body mass index were 59 [52.0;67.0] years and 28.2 [25.6;31.2] kg/m2, respectively. After a median [25th;75th percentile] follow-up of 41.2 [18.3;59.6] months, BP changes were similar between OSA and non-OSA groups. However, we observed an increase in BP in the third tertile of the AHI (AHI>40 events/h) with a maximum difference in mean BP of +3.3 mmHg at 30 months. OSA patients with good CPAP adherence (≥4 hours/night) reduced mean BP after 18 months compared to usual care/poor CPAP adherence patients, maximum mean difference (95% CI) of -4.7 (-6.7,-2.7) mmHg. In patients with severe OSA we observed a maximum mean difference of -7.1 (-10.3,-3.8) mmHg.In patients with ACS, severe OSA is associated with a long-term increase in BP, which is reduced by good CPAP adherence.