The effectiveness of enzyme replacement therapy on cardiac findings in patients with mucopolysaccharidosis.

Background This study aimed to determine cardiac findings in patients with mucopolysaccharidosis (MPS) and to assess the changes in these findings after enzyme replacement therapy (ERT). Methods A retrospective clinical cohort study was conducted on patients who were diagnosed with MPS between 1995 and 2018 in Hacettepe University, Division of Pediatric Metabolism. A total of 96 patients were diagnosed with MPS during the study period. Of these patients, 81 (84.3%) received ERT. Echocardiographic findings of the patients together with the 6-min walking test (6MWT) results before and after ERT were compared. Results Thirty-one participants (38.2%) were female, while 50 (61.8%) were male. The mean age of the participants was 11.97 ± 6.33 years (range: 1.8-30). Five patients (6.2%) had MPS type I, 14 (17.3%) had type II, 28 (34.6%) had type IVa, 33 (40.7%) had type VI and one (1.2%) had type VII. Before ERT, 69.4% of patients had mitral insufficiency (MI; mild: 40.5%, moderate: 16.5%, severe: 12.7%), 35.4% had aortic insufficiency (AI; mild: 22.8%, moderate: 12.7%) and 45.1% had tricuspid insufficiency (TI; mild: 39.2%, moderate: 2.5%). The median duration of the ERT was 3.5 years. The ERT significantly improved left ventricular hypertrophy (LVH), but all other study variables returned non-significant before and after treatment. ERT may improve LVH in MPS. Bearing in mind that MPS is a progressive disease, ERT seems to prevent significant deterioration of this ailment but is not able to reverse the already settled pathologies except for LVH. ERT is not able to reverse the damage, but provides stabilization; so it is best to initiate treatment before cardiac damage.