PB2218: ASSESSMENT OF CYSTATIN C IN PEDIATRIC SICKLE CELL DISEASE AND B-THALASSEMIA AS A MARKER OF SUBCLINICAL CARDIOVASCULAR DYSFUNCTION: A CASE-CONTROL STUDY - M. Beshir; D. Hanna; N. Khalifa; E. Baz; A. Elhewala (HemaSphere, 2022)