Exercise Capacity and Ventilatory Efficiency in Patients With Pulmonary Embolism After Short Duration of Anticoagulation Therapy

Background: Although anticoagulation therapy can reduce the risk for pulmonary embolism (PE) recurrence, symptoms such as exertional dyspnea or pain can persist for several months to years. Therefore, we aimed to assess the improvement of ventilatory efficiency and exercise capacity during cardiopulmonary exercise test in PE patients after short duration of anticoagulant therapy.

Materials and methods: Pulmonary function testing, arterial blood gas analysis and cardiopulmonary exercise test were performed in 30 PE patients after anticoagulant therapy of 4 weeks (early phase) and after 6 months (late phase). In addition, another 30 healthy volunteers underwent the same tests.

Results: Percentage of forced vital capacity (FVC %pred) improvement was evident in the PE group (P < 0.01) after 6 months of treatment. Peak Load, peak Load %pred, peak oxygen uptake (V∘O₂), peak V∘O₂%pred increased significantly after treatment for 6 months (P < 0.01), while lowest minute ventilation in relation to carbon dioxide production (V∘E / V∘CO₂) and lowest V∘E / V∘CO₂ %pred decreased significantly (P = 0.001). In PE group, the increment of peak V∘O₂ %pred from 4 weeks to 6 months correlated with the decrease of lowest V∘E / V∘CO₂ %pred (r = 0.639, P < 0.001) but not the increment of FVC %pred (r = 0.058, P = 0.769).

Conclusions: Exercise capacity improved significantly and there was a gradual improvement in ventilatory efficiency after 6 months of anticoagulation therapy.