There is some evidence for a hypercoagulable state in sleep apnea-hipopnea syndrome (SAHS), which could play a role in the increased cardiovascular morbility and mortality. Respiratory alterations (hypoxia, hypoxia- reoxygenation) and sleep fragmentation that these patients suffer during the sleep may induce modifications in clotting-fibrinolisis factors that may be a risk factor for venous thromboembolism (VTE).

OBJECTIVES:To calculate and compare the prevalence of sleep apnea-hipopnea syndrome in patients with venous thromboembolism with a gender, aged and BMI matched control group. Assessment of the association between SAHS and other risk factors for VTE. To compare clotting- fibrinolisis patterns, sleep parameters, blood pressure and pulmonary arterial obstruction index in patients with SAHS and VTE and those ones without SAHS.

DESIGN: Case-control study.

METHODS: 133 SAHS patients and 133 controls will be studied. The study includes:

a) medical history; b) anthropometric variables (weight, height, body mass index, Mallampati index); c) sleepiness tested by Epworth scale; d) London Chest Activity of Daily Living Scale; e) conventional polysomnography (PSG); f) testing: clotting-fibrinolisis factors (factor V, VII, VIII; C and S protein, plasminogen tissular activator (t-PA) and inhibitor of plasminogen activator (PAI-1); g) d-dimer and thrombin-antithrombin III complex; h) basic biochemical profile and hemograma; i) Pulmonary artery obstruction index.

Inclusion Criteria:

• Case group:
• Pulmonary embolism diagnosed by CT Pulmonary Angiography.
• Control group:
• randomly selected from among patients in two primary health care centers in Mallorca without tromboembolic disease

Exclusion Criteria:

• Refusal to sign informed consent.
• Expected survival less than 12 months
• Long-term oxygen therapy
• Hospital admission in the previous two months.
• Familiar thrombophilia