Study Shows 6-Month Warfarin Treatment Insufficient For Treating PE Aggravated by Obstructive Sleep Apnea Hypopnea Syndrome

Patrícia Silva, PhD avatar

by Patrícia Silva, PhD |

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A new study recently published in the Chinese Medical Journal revealed that a 6-month warfarin treatment might not be sufficient as an effective therapy for patients with pulmonary embolism complicated by obstructive sleep apnea hypopnea syndrome (OSAHS). The study was conducted by researchers at Beijing Anzhen Hospital in China and is entitled “Obstructive Sleep Apnea Hypopnea Syndrome as a Reason for Active Management of Pulmonary Embolism.

Pulmonary embolism refers to clots in the pulmonary arteries. Normally, the pulmonary embolism either resolves by itself or is successfully treated with medication. In situations where the clot is not disintegrated with medication, or there is a frequent recurrence of clots, the lungs may suffer vascular alterations that can lead to an abnormally high blood pressure in the pulmonary arteries, a phenomenon known as pulmonary hypertension. Patients with pulmonary embolism may experience chest pain, shortness of breaths and bloody cough. Treatment is usually through anticoagulant therapy, with warfarin being considered the most reliable anticoagulant. However, researchers note that caution should be taken when applying anticoagulant treatments due to a bleeding risk, and that prolonged anticoagulation therapy should be continuously re-evaluated.

OSAHS is a medical condition characterized by repetitive episodes of airflow reduction (hypopnea) or cessation (apnea) caused by an upper airway collapse during sleep. OSAHS is associated with an excessive daytime sleepiness, and has been previously reported to be more prevalent and severe among patients with pulmonary embolism. There are, however, few reports of the impact of anticoagulant treatment in patients with pulmonary embolism complicated by OSAHS, especially considering that a higher dose of warfarin is usually applied in more severe cases of OSAHS.

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The goal of the study was to assess whether routine warfarin treatment for 6 months would be effective enough in individuals with pulmonary embolism aggravated by OSAHS. The team analyzed 97 patients with pulmonary embolism, from whom 32 had OSAHS. Warfarin treatment was administered for 6 months and all the patients were followed-up for 18 months.

Researchers found that OSAHS patients required a higher warfarin dose in comparison to patients without OSAHS (4.73 mg and 3.61 mg, respectively). In terms of safety, no aggravation of the pulmonary embolism or major bleeding occurred during warfarin treatment, and the rate of adverse events was similar between pulmonary embolism patients with or without OSAHS, including hospitalization due to heart failure or pulmonary hypertension. After the 6-month warfarin therapy, researchers found that OSAHS patients had a higher recurrence of pulmonary embolism in comparison to patients without OSAHS (21.43% and 6.78%, respectively).

The research team concluded that patients with pulmonary embolism aggravated by OSAHS may present hypercoagulation, requiring a more aggressive treatment regimen with higher doses of anticoagulants. These patients are also at a higher risk for pulmonary embolism recurrence after cessation of a 6-month warfarin treatment, indicating that a 6-month routine anticoagulation treatment is not enough for treating pulmonary embolism complicated by OSAHS. The authors suggest that further studies should be conducted to determine whether prolonged anticoagulant treatment would benefit this patient population.