Clinical usefulness of tissue Doppler imaging in predicting preclinical Fabry cardiomyopathy.

UNLABELLED: Fabry cardiomyopathy (FC) is characterized by left ventricular hypertrophy (LVH). The aim of this study is to determine whether early changes revealed by tissue Doppler imaging (TDI) are useful for detecting preclinical cardiac abnormalities in patients with this X-linked genetic disorder. If so, this tool could help in deciding whether to begin enzymatic therapy earlier than otherwise. METHODS AND
RESULTS: 59 consecutive patients with confirmed Fabry disease (FD) underwent conventional and TD echocardiography. FD patients with and without LVH had significantly lower early diastolic tissue Doppler velocities (Ea) compared with the control group (P<0.001); The isovolumic relaxation time (IVRT) was significantly longer in the FD group with LVH (P<0.001). Isovolumic contraction time (IVCT) was significantly shorter in the FD group without LVH compared with the control group (P<0.001). Additionally, peak systolic wall motion velocity (Sa) was significantly lower in patients with LVH, compared with those without LVH (P<0.001). The systolic myocardial velocity correlates inversely with septum and posterior wall thickness (r: -0.74 and r: -0.90; P<0.001 respectively). In respect of predicting preclinical cardiac impairment, the area under the ROC curve of 0.83 suggests an optimal IVRT cut-off point of 60 ms for separating early cardiac impairment from the established condition. This gives a 96.6% specificity rate for the early detection of cardiac involvement. The best parameter for detecting preclinical FC is the IVCT, with a cut-off point of 105 ms, which shows high sensitivity and specificity (100% and 91%, respectively; AUC: 0.97).
CONCLUSIONS: Myocardial contraction and relaxation evaluation confirms that TDI is a reliable method for early identification of preclinical FC, even before FC patients develop LVH.