重型β型地中海贫血患儿BNP和铁超负荷与早期心功能不全的关系研究

Relationship among BNP, Iron Overload and Early Cardiac Dysfunction in Children with Severe β-thalassemia

【目的】探讨重型B型地中海贫血患儿β型尿钠肽（BNP）和铁超负荷与早期心功能不全的关系。【方法】选择2014年1月至2016年1月本院收治的42例重型β型地中海贫血患儿为研究对象（观察组），选取同期40例健康儿童作为对照组，超声心动图检测心脏各参数，采集血标本检测血红蛋白、BNP和铁蛋白等指标。根据观察组是否合并舒张功能障碍分为E／E’（二尖瓣口舒张早期血流速度／室间隔舒张早期运动速度）〈9和E／E’≥9两组，比较两组心脏各参数和血生化指标。【结果】观察组BNP和铁蛋白水平显著高于对照组，而血红蛋白低于对照组，差异均具有统计学意义（P〈0．05）；观察组左室舒张末期内径（LVED）、左室收缩末期内径（LVES）、左房直径（LV）、右室直径（RV）、左房容积指数（LAVI）和左室质量指数（LVMI）均高于对照组，差异均具有统计学意义（P〈0．05）；观察组E、二尖瓣口舒张晚期血流速度（A）、E／E’均高于对照组，等容舒张时间（IVRT）、室间隔收缩期运动速度（S’）、E’均低于对照组，其差异均具有统计学意义（P〈0．05）。E／E’≥9组E、E／E’、LVES、LVED、LA、LAVI和LVMI均高于E／E’〈9组，E’低于于E／E’〈9组，差异均具有统计学意义（P〈0．05）。观察组BNP水平与铁蛋白呈正相关（r=0．939，P=0．ooo），与血红蛋白无明显相关性（r=0．102，P=0．436）；与S’和室间隔舒张晚期运动速度（A’）均呈负相关（r=-0．300、-0．421，P=0．043、0．031），与E／E’无相关性（r=0．082，P=0．519）。E／E’〈9组中，BNP水平与铁蛋白呈正相关（r=0．835，P=0．000），与E／A比值呈正相关（r：0．438，P=0．029）。E／E’≥9组中，BNP水平与铁蛋白亦呈正相关（r=0．949，P=0．000），与LAVI呈正相关（r=0．396，P=0．026）；BNP与s’和A’均呈负相关（r=-0．401、-0．409，P=0．035、0．036）。【结论】重型13型地中海贫血儿童BNP水平与舒张功能障碍有关的参数无明显相关性，而与铁超负荷明显相关，可在一定程度上反映其心功能损害。

[ Objective] To investigate the relationship among BNP, iron overload and early cardiac dysfunction in severe β-thalassemia children. [ Methods ] A total of 42 patients with severe I3 thalassemia （ observation group） from January 2014 to January 2016 in our hospital were enrolled in this study. In the same period time, 40 healthy children were collected as control group. All cases were checked by echocardiography for cardiac parameters and their blood specimen were measured for hemoglobin, BNP, ferritin and other indicators. According to whether there was presence of diastolic dysfunction or not, the observation group were further divided into two subgroups, E / E 〈 9 and E / E≥9 groups, based on the ratio of E / E ＇ （ early diastolic mitral flow velocity / septal early diastolic velocity） . In between the two subgroups, patients＇cardiac parameters and blood biochemical indices were compared as well. [ Results] BNP and ferritin levels in the observation group were significantly higher than those in the control group while hemoglobin was lower; the differences were statistically significant （ P 〈 0.01 ）. LVED （ left ventricular end diastolic diameter）, LVES （ left ventric- ular end systolic diameter）, LA （left atrial diameter）, RV （fight ventricular diameter）, LAVI （left atrial volume index） and LVMI （left ventricular mass index） in the observation group were significantly higher than those in the control group, the differences were statistically significant （P 〈 0.05）. E （early diastolic mitral flow velocity）, A （late diastolic mitral flow velocity） and E / E ＇（ septal early diastolic velocity） in the observation group were higher than those in the control group, while IVRT （isovolumic relaxation time）, S＇（ septal systolic velocity） and E＇（ septal early diastolic velocity） were lower than those in the control group ; the differences were statistically significant （ P 〈 0.05 ）. In the E / E＇≥ 9 subgroup, E, E / E ＇, LVES, LVED, LA, LAVI and LVMI were higher than those in the E / E＇ 〈 9 subgroup （P 〈 0.05）, however, its E is lower than in the E/E＇ 〈 9 subgroup （P 〈 0.05）. BNP and ferritin levels were positively correlated in the observation group （ r = 0. 939, P = 0. 000） ; levels of BNP and hemoglobin showed no significant correlation （ r = 0. 102,P = 0.436）. In the observation group, BNP was negatively correlated with S＇and A＇（ septal late diastole） （r = - 0. 300, -0. 421,P = 0. 043,0.031 ）. BNP showed no correlation with E/E＇（ r = 0. 082, P = 0. 519）. In the E / E ≤ 9 subgroup, BNP and ferritin levels were positively correlated （r =0. 835 ,P =0. 000） and BNP and E / A ratio was posi- tively correlated （r = 0. 438, P = 0. 029 ）. In E / E≥19 group, BNP levels and ferritin was positively related （r = 0. 949, P = 0.000 ） and BNP was positively correlated with LAVI （ r = 0. 396, P = 0.026 ）. Further BNP showed negative correla- tion with S＇and A＂ （ r = - 0. 401, - 0. 409, P = 0. 035, 0. 036）. [ Conclusion ] BNP levels and diastolic dysfunction showed no significant correlation in severe β-thalassemia children. However, BNP had significant correlation with iron overload, which to some extent reflects cardiac dysfunction.