Division of Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio.
Pediatr Blood Cancer. 2019 Jun;66(6):e27703. doi: 10.1002/pbc.27703. Epub 2019 Mar 7.
Sickle cell anemia (SCA) patients frequently have many comorbidities, including diastolic dysfunction (DD) and exercise intolerance. SCA patients often cannot reach maximal effort on exercise testing; little is known regarding whether submaximal exercise parameters can predict abnormal maximal exercise results in SCA patients and if there are any possible associations with DD.
A prospective longitudinal study was performed in SCA patients. All patients had a resting cardiac MRI (CMR), cardiopulmonary exercise test (CPET) with cycle ergometry using a ramp protocol, and an echocardiogram. Exercise data were compared with age-, gender-, and size-matched normal controls.
Compared with normal controls, the SCA group (n = 19) had lower mean max oxygen consumption (VO ; 1378 ± 412 mL/min vs 2237 ± 580, P < 0.01) and workload (117 ± 37.6 watts vs 175 ± 50.5 watts, P = 0.0003). When evaluating the submaximal exercise parameters, there was lower VO at the anaerobic threshold (AT; 950 ± 311.7 vs 1460 ± 409.9, P < 0.01) and oxygen uptake efficiency slope (OUES) at AT (1512 ± 426.2 vs 2080 ± 339, P < 0.01). The max VO strongly correlated with VO at AT (r = 0.9, P < 0.01) and OUES (r = 0.83, P < 0.01) at AT. The VO at AT correlated with hematocrit (r = 0.77, P < 0.05). The OUES correlated with left ventricular ejection fraction by CMR (r = 0.55, P = 0.01), hematocrit (r = 0.52, P = 0.02), and lateral E/e' (r = -0.54, P = 0.01).
SCA patients have abnormal submaximal exercise measures compared with controls, which is strongly associated with abnormal maximal exercise results. The degree of submaximal abnormality correlates with DD abnormalities by echocardiography. These data expand the scope of functional cardiovascular abnormalities in SCA.
镰状细胞贫血（SCA）患者常伴有多种合并症，包括舒张功能障碍（DD）和运动不耐受。SCA 患者在运动试验中通常无法达到最大努力；关于亚最大运动参数是否可以预测 SCA 患者异常的最大运动结果，以及是否与 DD 有任何关联，知之甚少。
对 SCA 患者进行前瞻性纵向研究。所有患者均进行静息心脏磁共振（CMR）、心肺运动试验（CPET），并使用斜坡方案进行踏车运动，以及进行超声心动图检查。将运动数据与年龄、性别和体型匹配的正常对照组进行比较。
与正常对照组相比，SCA 组（n=19）的平均最大耗氧量（VO ）较低（1378±412mL/min 比 2237±580mL/min，P<0.01）和工作负荷（117±37.6 瓦比 175±50.5 瓦，P=0.0003）。在评估亚最大运动参数时，无氧阈（AT）时的 VO 较低（950±311.7 比 1460±409.9，P<0.01），AT 时的摄氧量效率斜率（OUES）也较低（1512±426.2 比 2080±339，P<0.01）。最大 VO 与 AT 时的 VO （r=0.9，P<0.01）和 OUES（r=0.83，P<0.01）高度相关。AT 时的 VO 与红细胞压积（r=0.77，P<0.05）相关。OUES 与 CMR 左心室射血分数（r=0.55，P=0.01）、红细胞压积（r=0.52，P=0.02）和外侧 E/e'（r=-0.54，P=0.01）相关。
与对照组相比，SCA 患者的亚最大运动测量值异常，与异常的最大运动结果密切相关。亚最大异常的程度与超声心动图检查的 DD 异常相关。这些数据扩展了 SCA 功能性心血管异常的范围。
