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

Abstract

Background—: Noninvasively assessed pulmonary pressure elevations and left ventricular (LV) diastolic dysfunction are associated with increased mortality in adults with sickle cell disease, but their relationship to exercise intolerance has not been evaluated prospectively. Methods and Results—: Echocardiography, 6-minute walk distance, hemolytic rate, and serum concentrations of ferritin and erythropoietin were evaluated in a cohort of 483 subjects with homozygous hemoglobin S in the US and UK Walk–Treatment of Pulmonary Hypertension and Sickle Cell Disease with Sildenafil Therapy (Walk-PHaSST) study. Tricuspid regurgitation velocity, which reflects systolic pulmonary artery pressure, was 2.7 to P P =0.0001), blood urea nitrogen ( P =0.0002), and erythropoietin ( P =0.002) were independently associated with an increased tricuspid regurgitation velocity. Furthermore, female sex ( P P P =0.014), and tricuspid regurgitation velocity ( P =0.019) were independent predictors of a shorter 6-minute walk distance. Conclusions—: Echocardiography-estimated elevated pulmonary artery systolic pressure and LV lateral E/e′ ratio were independently associated with poor exercise capacity in a large cohort of patients with sickle cell anemia. Controlled trials investigating whether strategies to prevent or delay pulmonary hypertension and/or LV diastolic dysfunction will improve exercise capacity and long-term outcomes in sickle cell anemia should be considered. Clinical Trial Registration—: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00492531.