Braden D S, Covitz W, Milner P F
Department of Pediatric, University of Mississippi, Jackson, USA.
Am J Hematol. 1996 Jun;52(2):96-102. doi: 10.1002/(SICI)1096-8652(199606)52:2<96::AID-AJH5>3.0.CO;2-0.
Cardiac function was measured at rest and during exercise in 9 patients with sickle-cell anemia (SS) and coexisting homozygous alpha thalassemia-2 (alpha thal-2). Results were compared with 18 sickle cell patients with normal alpha globin genes, who were matched to the study group by age, gender, and size, and to published normal values. SS alpha thal-2 patients were less anemic: 9.9 +/- 1.0 vs 8.2 +/- 1.2 gm/dl for SS alone (P<.05). Left ventricular dimensions were normal in SS alpha thal-2 (4.9 +/- 0.7 cm), but increased in SS (5.4 +/- 0.7, cm P=.05) (normal range, 3.7-5.6 cm). Left ventricular wall thickness was, however, dramatically increased in the SS alpha thal-2 patients (free wall, 1.8 +/- 0.6 cm; septum, 1.6 +/- 0.4 cm), though SS controls had normal wall thickness (free wall, 1.0 +/- 0.2 cm; septum, 1.0 +/- 0.2 cm, P<.001) (normal range, 0.6-1.1 cm). At rest, Doppler indices of systolic function were not significantly different between sickle groups and normal values. SS alpha thal-2 patients did have abnormal diastolic filling at rest, as evidenced by a reduced ratio of early/late diastolic filling, 1.4 +/- 0.3 vs. 2.0 +/- 0.5 for SS controls (P<.01), and 1.8 +/- 0.4 for normals. An analysis of covariance suggested that this abnormality persisted after taking into account the previously demonstrated hypertrophy. During exercise, SS alpha thal-2 patients had higher heart rates and blood pressures than SS controls in spite of performing the same or less work. This resulted in a higher double product (an estimate of oxygen consumption) in SS alpha thal-2 patients (37,470 +/- 2,310 mm Hg-BPM) than in SS controls (33,310 +/- 1,490 mm Hg-BPM, P<.01). Work capacity, peak heart rate, and blood pressure were all abnormally decreased in both sickle-cell groups when compared to normal. Cardiac abnormalities noted at rest and during exercise in SS alpha thal-2 patients suggest a role of microvascular occlusion and a protective effect of decreased hemoglobin.
对9例镰状细胞贫血（SS）合并纯合子α地中海贫血-2（αthal-2）患者在静息和运动状态下的心脏功能进行了测量。将结果与18例α珠蛋白基因正常的镰状细胞患者进行比较，这些患者在年龄、性别和体型上与研究组相匹配，并与已发表的正常数值进行比较。SSαthal-2患者贫血程度较轻：血红蛋白水平为9.9±1.0 g/dl，而单纯SS患者为8.2±1.2 g/dl（P<0.05）。SSαthal-2患者的左心室尺寸正常（4.9±0.7 cm），但SS患者的左心室尺寸增大（5.4±0.7 cm，P = 0.05）（正常范围为3.7 - 5.6 cm）。然而，SSαthal-2患者的左心室壁厚度显著增加（游离壁为1.8±0.6 cm；室间隔为1.6±0.4 cm），而SS对照组的心室壁厚度正常（游离壁为1.0±0.2 cm；室间隔为1.0±0.2 cm，P<0.001）（正常范围为0.6 - 1.1 cm）。静息时，镰状细胞组与正常数值之间的收缩功能多普勒指标无显著差异。SSαthal-2患者静息时舒张期充盈异常，表现为舒张早期/晚期充盈比值降低，SS对照组为1.4±0.3，而SS对照组为2.0±0.5（P<0.01），正常人为1.8±0.4。协方差分析表明，在考虑到先前证实的心肌肥厚后，这种异常仍然存在。运动期间，尽管SSαthal-2患者完成的工作量相同或更少，但他们的心率和血压高于SS对照组。这导致SSαthal-2患者的双乘积（氧耗量估计值）更高（37,470±2,310 mmHg - BPM），高于SS对照组（33,310±1,490 mmHg - BPM，P<0.01）。与正常相比，两个镰状细胞组的工作能力、峰值心率和血压均异常降低。在SSαthal-2患者静息和运动时观察到的心脏异常表明微血管阻塞起了作用，而血红蛋白降低具有保护作用。
