Improvement of cardiac function during enzyme replacement therapy in patients with Fabry disease: a prospective strain rate imaging study.

BACKGROUND Enzyme replacement therapy (ERT) has been shown to enhance microvascular endothelial globotriaosylceramide clearance in the hearts of patients with Fabry disease. Whether these results can be translated into an improvement of myocardial function has yet to be demonstrated. METHODS AND RESULTS Sixteen patients with Fabry disease who were treated in an open-label study with 1.0 mg/kg body weight of recombinant alpha-Gal A (agalsidase beta, Fabrazyme) were followed up for 12 months. Myocardial function was quantified by ultrasonic strain rate imaging to assess radial and longitudinal myocardial deformation. End-diastolic thickness of the left ventricular posterior wall and myocardial mass (assessed by magnetic resonance imaging, n=10) was measured at baseline and after 12 months of ERT. Data were compared with 16 age-matched healthy controls. At baseline, both peak systolic strain rate and systolic strain were significantly reduced in the radial and longitudinal direction in patients compared with controls. Peak systolic strain rate increased significantly in the posterior wall (radial function) after one year of treatment (baseline, 2.8+/-0.2 s(-1); 12 months, 3.7+/-0.3 s(-1); P<0.05). In addition, end-systolic strain of the posterior wall increased significantly (baseline, 34+/-3%; 12 months, 45+/-4%; P<0.05). This enhancement in radial function was accompanied by an improvement in longitudinal function. End-diastolic thickness of the posterior wall decreased significantly after 12 months of treatment (baseline, 13.8+/-0.6 mm; 12 months, 11.8+/-0.6 mm; P<0.05). In parallel, myocardial mass decreased significantly from 201+/-18 to 180+/-21 g (P<0.05). CONCLUSIONS These results suggest that ERT can decrease left ventricular hypertrophy and improve regional myocardial function.