Abstract
Background Nephropathic cystinosis is a rare autosomal recessive lysosomal storage disorder that initially affects the kidney progressing to multi-organ failure due to accumulation of cystine in all tissue compartments. Objective The main objective of this study is the evaluation of cardiac function in cystinosis patients using non-conventional echocardiographic modalities like pulsed wave tissue Doppler imaging (PW-TDI) and 2D speckle tracking echocardiography (2D-STE). Methods This is a case control study conducted on fifteen patients with cystinosis and 15 normal controls. Echocardiography was done for all participants and PW-TDI was performed for measurement of S ', E ', A ' velocities and myocardial performance index (MPI) at basal parts of septal, left ventricle (LV), and right ventricle (RV) free walls. 2D-STE was done for evaluation of global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) of LV. Mitral E and A velocities and tricuspid annular plane systolic excursion (TAPSE) were also measured. Results The GLS, GRS, and S ' velocity at basal septum and LV lateral wall were significantly lower in patients denoting LV systolic dysfunction (p = 0.005,p < 0.0001,p = 0.001,p = 0.006, respectively), while E/E ' were significantly higher in patients group denoting LV diastolic dysfunction (p < 0.001). For RV function, TAPSE, S ', and E ' velocity were significantly lower in patients group (p0.013,p < 0.01,p = 0.05, respectively) indicating RV systolic and diastolic dysfunction. The TDI-derived MPI for both LV and RV were significantly higher in patients group (p < 0.0001,p < 0.01, respectively) indicating both ventricular systolic and diastolic dysfunction. For prediction of cardiac dysfunction among patients, the receiver operating characteristic (ROC) curve showed that GRS <= 29% had sensitivity 93.3% and specificity 100%, GLS > - 20.1% had sensitivity 66.7% and specificity 93.3%, LV-E/E ' >7.87 had sensitivity 73.3% and specificity 93.3%, and MPI-LV > 0.36 had sensitivity 100% and specificity 93.3% while MPI-RV > 0.29 had sensitivity 80% and specificity 93.3% and TAPSE <= 19 mm had sensitivity 80% and specificity 73.3%. Conclusions Patients with cystinosis have significant both left and right ventricular dysfunction, which can be better evaluated using the non-conventional echocardiographic modalities like TDI and 2D-STE for early detection of subtle cardiac dysfunction.