Evaluation of Cardiac Function in Systemic Sclerosis with Novel Echocardiographic Technologies

摘要

Systemic sclerosis (SSc) is a connective tissue disease characterized by widespread vascular lesions. Primary myocardial involvement is common in SSc and, when clinically evident, appears as a poor prognostic factor. Using conventional methods, myocardial perfusion impairment and biventricular dysfunction have been reported in SSc. Recently, Tissue Doppler Imaging (TDI) echocardiography and magnetic resonance imaging have confirmed these results. TDI, with its derived strain, strain rate and myocardial performance index, is a powerful new echocardiographic tool that is now becoming the standard for assessing ventricular function in a variety of situations and diseases. In the present article we review the main published data on the application of TDI in the evaluation of cardiac function and prediction of prognosis in patients with SSc. Introduction Systemic sclerosis (SSc) is a multisystem disorder characterized by diffuse vascular lesions and fibrosis of the skin and internal organs (1,2). Cardiac involvement is a common finding in SSc, but often clinically occult. In fact, clinical evidence of myocardial disease may be found in 20-25% of patients with SSc, while at postmortem examination the heart is affected in up to 80% of patients (3,4). The course and prognosis are highly dependent on the clinical pattern, and the main causes of death are cardiovascular, renal and pulmonary disease. Heart involvement is one of the main factors shortening the survival of SSc patients (5). Although cardiac abnormalities could be more prevalent and severe in the diffuse cutaneous subtype of the disease, there is increasing evidence suggesting that cardiac involvement is also a frequent finding in the limited cutaneous subtype. In the large epidemiological Italian study, although heart symptoms were found more frequently in the diffuse form (32%) as compared with the limited form (23%), the difference was not statistically significant (6). Some data have even suggested a more prevalent involvement in the limited subtype of the disease (7). Magnetic resonance imaging, single photon emission computed tomography, echocardiography and radionuclide ventriculography have been used to investigate myocardial perfusion and contractility. The data showed that myocardial perfusion abnormalities together with various degrees of biventricular dysfunction were common. Moreover, echocardiography and radionuclide ventriculography may be influenced by loading conditions and adjacent segment motion (8,9). Tissue Doppler Imaging (TDI) has been introduced as a quantitative, more objective, and sensitive method for the assessment of myocardial function. It is a new approach that allows direct and valid measurement of myocardial velocities and strain rate (10,11). Myocardial strain rate has been shown to be a strong index of contractility, independent of myocardial translation and less dependent on loading conditions. Furthermore, strain rate determined by TDI is a more sensitive method than conventional echocardiography or radionuclide ventriculography for detecting changes in myocardium contractility (12,13,14). The myocardial performance index has been considered a good predictor for adverse results in several cardiac diseases, such as valvular insufficiency, cardiomyopathies and acute myocardial infarction. It is easy to obtain, however, using TDI to obtain myocardial performance index (representing regional systolic and diastolic function) is not a universally accepted method (15,16,17).Based on these grounds, the purpose of the present review is to describe the rationale behind and clinical use of TDI, strain rate and myocardial performance index in the assessment cardiac function, prediction of prognosis and distinguishing cutaneous subtypes in patients with SSc, and their relation to other instrumental features of the disease, with focus on recent developments (Table 1).