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Exercise tolerance, lung function abnormalities, anemia, and cardiothoracic ratio in sickle cell patients
Author(s) -
van Beers Eduard J.,
van der Plas Mart N.,
Nur Erfan,
Bogaard HarmJan,
van Steenwijk Reindert P.,
Biemond Bart J.,
Bresser Paul
Publication year - 2014
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.23752
Subject(s) - medicine , interquartile range , pulmonary function testing , cardiology , vital capacity , anemia , acute chest syndrome , lung , sickle cell anemia , pulmonary hypertension , vo2 max , lung volumes , diffusing capacity , disease , heart rate , lung function , blood pressure
Many patients with sickle cell disease (SCD) have a reduced exercise capacity and abnormal lung function. Cardiopulmonary exercise testing (CPET) can identify causes of exercise limitation. Forty‐four consecutive SCD patients (27 HbSS, 11 HbSC, and 6 HbS‐beta thalassemia) with a median age (interquartile range) of 26 (21–41) years underwent pulmonary function tests, CPET, chest x‐ray, and echocardiography to further characterize exercise limitation in SCD. Peak oxygen uptake (V′O 2 ‐peak), expressing maximum exercise capacity, was decreased in 83% of the studied patients. V′O 2 ‐peak correlated with hemoglobin levels ( R = 0.440, P = 0.005), forced vital capacity (FVC) ( R = 0.717, P < 0.0001). Cardiothoracic ratio on chest x‐ray inversely correlated with FVC ( R = −0.637, P < 0.001). According to criteria for exercise limitation, the patients were limited in exercise capacity due to anemia ( n = 17), cardiovascular dysfunction ( n = 2), musculoskeletal function ( n = 10), pulmonary ventilatory abnormalities ( n = 1), pulmonary vascular exercise limitation ( n = 1), and poor effort ( n = 3). In the present study we demonstrate that anemia is the most important determinant of reduced exercise tolerance observed in SCD patients without signs of pulmonary hypertension. We found a strong correlation between various parameters of lung volume and cardiothoracic ratio and we hypothesize that cardiomegaly and relative small chest size may be important causes of the impairment in pulmonary function, that is, reduced long volumes and diffusion capacity, in SCD. Taking into account anthropomorphic differences between SCD patients and controls could help to interpret lung function studies in SCD better. Am. J. Hematol. 89:819–824, 2014. © 2014 Wiley Periodicals, Inc.