Improvement in serial cardiopulmonary exercise testing following enzyme replacement therapy in Fabry disease.
BACKGROUND
Fabry disease is an X-linked genetic disorder resulting in the accumulation of glycosphingolipids in various organs, leading to exercise intolerance and early mortality. Enzyme replacement therapy (ERT) has recently been approved for use in Fabry patients. GOALS OF STUDY: To assess baseline cardiopulmonary exercise characteristics in both invasive and noninvasive tests and to study the impact of ERT on exercise.


METHODS
A total of 15 patients with Fabry disease underwent baseline cardiopulmonary exercise tests. Six patients were randomized 2:1 to receive either ERT or placebo. We performed serial cardiopulmonary exercise tests at baseline and every 3 months over a period of at least 18 months. The baseline test was compared to the last two exercise tests for each patient.


RESULTS
Mean age was 32 years. Mean VO2max was 1.680 +/- 0.67 L/min and increased by 0.459 +/- 0.64 L/min in the patients receiving ERT. Mean VO2max was 1.462 +/- 0.25 L/min and decreased by 0.116 +/- 0.44 L/min in patients on placebo. Mean oxygen pulse (VO2/HR) increased by 1.71 with enzyme, but increased only 0.025 in patients taking placebo. Estimated stroke volume (SV) increased by 10 ml in patients on ERT.


CONCLUSIONS
In this small cohort, exercise tolerance increased in patients receiving enzyme replacement therapy. Cardiopulmonary exercise testing is a useful test in measuring the response to therapy in Fabry disease patients.
Bierer
Gregory
G
Division of Pulmonary/Critical Care Medicine, Cedars-Sinai Medical Center and UCLA School of Medicine, Los Angeles, California, USA. gregory.bierer@cshs.org
Balfe
David
D
Wilcox
William R
WR
Mosenifar
Zab
Z
D000328:Adult; D002319:Cardiovascular System / Q000187:drug effects*; D015331:Cohort Studies; D015444:Exercise; D000795:Fabry Disease / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D010919:Placebos; D011659:Pulmonary Gas Exchange; D013318:Stroke Volume; D013997:Time Factors; D000519:alpha-Galactosidase / Q000627:therapeutic use*
D010919:Placebos; D000519:alpha-Galactosidase; D010100:Oxygen