Cardiovascular Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, via F. Sforza 35, 20122, Milan, Italy.
Rare Diseases Center, Department of Medicine and Medical Specialties, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy.
Intern Emerg Med. 2017 Sep;12(6):799-809. doi: 10.1007/s11739-017-1670-4. Epub 2017 Apr 29.
Traditional echocardiography is unable to detect neither the early stages of iron overload cardiomyopathy nor myocardial iron deposition. The aim of the study is to determine myocardial systolic strain indices in thalassemia major (TM), and assess their relationship with T2*, a cardiac magnetic resonance index of the severity of cardiac iron overload. 55 TM cases with recent cardiac magnetic resonance (CMR-T2*) underwent speckle tracking analysis to assess regional myocardial strains and rotation. The results were compared with a normal control group (n = 20), and were subsequently analyzed on the basis of the CMR-T2* values. Two TM groups were studied: TM with significant cardiac iron overload ("low" T2*, ≤20 ms; n = 21), and TM with normal T2* values ("normal" T2*, >20 ms; n = 34). TM patients show significant, uniform decrease in circumferential and radial strain (P < 0.05), and a remarkable reduction in end-systolic rotation, both global, and for all segments (P < 0.001). No significant differences were found between the low- and the normal T2* group either in regional strains and rotation or in standard echocardiographic and CMR parameters. Spearman's correlation coefficient shows no significant correlation between myocardial strains, rotation and cardiac T2* values. In conclusion, our results are in accordance with recent evidence that myocardial iron overload is not the only mechanism underlying iron cardiomyopathy in TM. Strain imaging can predict subclinical myocardial dysfunction irrespective of CMR-T2* values, although it cannot replace CMR-T2* in assessing cardiac iron overload. Finally, it might be useful to appropriately time cardioactive treatment.
传统超声心动图既不能检测铁过载性心肌病的早期阶段，也不能检测心肌铁沉积。本研究旨在确定重型地中海贫血（TM）患者的心肌收缩应变指数，并评估其与 T2的关系，T2是心脏铁过载严重程度的心脏磁共振指标。55 例最近接受心脏磁共振（CMR-T2*）检查的 TM 患者接受斑点追踪分析以评估局部心肌应变和旋转。结果与正常对照组（n=20）进行比较，并根据 CMR-T2值进行分析。研究了两组 TM：具有显著心脏铁过载的 TM（“低”T2，≤20 ms；n=21）和 T2值正常的 TM（“正常”T2，>20 ms；n=34）。TM 患者的圆周和径向应变明显降低（P<0.05），并且整体和所有节段的收缩末期旋转明显降低，均为显著（P<0.001）。低 T2组和正常 T2组之间的局部应变和旋转以及标准超声心动图和 CMR 参数均无显著差异。Spearman 相关系数显示心肌应变、旋转与心脏 T2值之间无显著相关性。总之，我们的结果与最近的证据一致，即心肌铁过载不是 TM 中铁性心肌病的唯一机制。应变成像可以预测亚临床心肌功能障碍，而与 CMR-T2值无关，尽管它不能替代 CMR-T2*来评估心脏铁过载。最后，它可能有助于适时进行心脏活性治疗。
