Letter by Farmakis and Aessopos regarding article, "echocardiographic markers of elevated pulmonary pressure and left ventricular diastolic dysfunction are associated with exercise intolerance in adults and adolescents with homozygous sickle cell anemia in the United States and United kingdom". - Farmakis D; Aessopos A; Farmakis, Dimitrios; Aessopos, Athanasios (Circulation, 2012)