Fístula arterio-venosa como tratamiento de EPOC grave

Abstract

COPD patients have dyspnea limiting their exercise capacity due to different mechanisms. The origin of the arterial blood gases anomaly is an alteration of the ventilation/perfusion (V'/Q') ratio causing venous admixture which has not been addressed therapeutically so far. Theoretically an arteriovenous fistula (AVF) could increase venous content of O2 so that blood leaving the left ventricle has a higher than expected PaO2 .This, along with the associated increase in cardiac output leads to an increased delivery of O2 to tissues particularly skeletal muscle thus improving its performance. We present a patient with advanced COPD. Full conventional therapy failed to improve his dyspnea and hypoxemia which limits his exercise capacity. We made a peripheral arteriovenous fistula on him as a therapeutic intent. Spirometry showed an initial FEV1 of 0.74 L, a FVC of 1.97 L, he had hypoxemia (PaO2 :56.8 mmHg, oxyhemoglobin saturation (SaO2 ): 82.9%). A 6 min walking test with a distance of300 m corresponding to 61% of predetermined value that improved by 108 m providing O2 2 L/min. Echocardiography showed a pulmonary artery systolic pressure of 26 mm Hg and a 60% of left ventricle ejection fraction. The patient obtained 73.8% in Saint George's Respiratory Questionnaire (SGRQ), 38 points in COPD Assesment Test (CAT) and 6 points in BODE Index. After 4 weeks of AVF neither spirometric nor echocardiographic changes were observed, but there was an improvement in PaO2 to 68 mmHg and in SaO2 to 93%. The 6 min walking test showed an increase to 425 m. SGRQ improved to 3.88 points, BODE index improved to 3 points and CAT to 21 points. We conclude that in this patient an AVF determined an improvement in exercise capacity with a better control of disease that resulted in a better quality of life constituting an important non pharmacological aid in an advanced COPD patient who failed to improve with full medical therapy. In patients selection is important to evaluate cardiovascular and peripheral vascular status since in theory AVF could lead to a right ventricle failure and peripheral blood steal syndrome.