Effects of NCPAP therapy on prothrombin activation in patients with obstructive sleep apnoea syndrome [Effekte der nCPAP-therapie auf die prothrombinaktivierung bei patienten mit obstruktivem schlafapnoesyndrom]

Obstructive sleep apnoea syndrome (OSAS) is associated with an increased risk for cardiovascular diseases. Question of the study: Previous investigations demonstrated a prothrombin activation in patients with untreated OSAS. These patients also had additional concurrent risk factors for prothrombin activation such as hypertension, obesity, diabetes, or coronary artery disease. Therefore, this study investigated the effect of adequate therapy of OSAS on prothrombin activation. Patients and methods: In all patients referred to the sleep laboratory with the diagnosis of OSAS after diagnostic polysomnography, levels of prothrombin fragments 1 and 2(F 1 + 2), thrombin-antithrombin complex (TAT), fibrin monomer and D-dimer were measured. Patients were treated with nasal continuous positive airway pressure (nCPAP). After a treatment period of 4-6 weeks, polysomnography and the coagulation tests were repeated. Results Twenty-three consecutive patients were included in this study (21 male; age: 50.3 ± 11.5 years; BMI: 31.7 ± 5.5 kg/m2). All patients had severe OSAS (AHI: 44.4 ± 26.5/h; desaturation index: 45.3 ± 17.8/h). Sufficient treatment with nCPAP was achieved in all patients (mean CPAP pressure: 7.9 ± 0.6 mbar; daily usage: 6.3 ± 2.1/h; AHI: 3.1 ± 2.3/h; desaturation index: 2.3 ± 1.8/h). On study-inclusion values for F 1 + 2 and TAT were significantly increased. After treatment with nCPAP, a highly significant decrease could be demonstrated (F 1 + 2: 6.55 ± 3.57 vs. 1.85 ± 2.59; TAT: 53.1 ± 16.4 vs. 13.6 ± 18.5; P < 0.001). Fibrin monomer and D-dimers were not detectable at increased levels at any point during the study. Conclusions: Patients with OSAS have an increased level of prothrombin activation. This can be reduced significantly with nCPAP therapy.