Assessment of a new index of myocardial strain for the diagnosis of cardiac sarcoidosis

Abstract Background The diagnosis of cardiac involvement in sarcoidosis is challenging and often expensive. Purpose The aim of this study is to assess whether a new strain index proposed by the authors has incremental value in the evaluation of cardiac involvement, compared to the use of left ventricular (LV) global longitudinal strain (GLS). Methods This is a single-center, non-blinded, pilot cross-sectional study. Patients of both genders, >18 years old, with confirmed diagnosis of cardiac sarcoidosis according to the Heart Rhythm Society criteria, and controls consisting of individuals diagnosed with systemic sarcoidosis without cardiac involvement, were included. Patients with obesity grade 2 or higher , moderate or severe primary heart valve disease, myocardial diseases of other etiologies, established coronary artery disease, and inadequate acoustic window were excluded. All patients underwent transthoracic echocardiography, with subsequent measurements performed on a workstation. The following LV indexes were evaluated: GLS and the new proposed index, calculated by the ratio between LVEF and the sum of the two segments with the lowest absolute strain values. ROC curves were calculated for both parameters using an online dedicated software, with determination of the optimal cutoff point for both variables, corresponding to the point of highest sensitivity and specificity. Confidence intervals were established by the DeLong method, and curves were compared using the Bonferroni method. A two-tailed p value of 0.05 was considered significant. Results Twenty patients with cardiac involvement and twenty patients without cardiac involvement were evaluated. The results of the variables are presented in table 1. Conclusions The new index showed a larger area under the curve compared to isolated GLS, as well as higher sensitivity and specificity for the identified cutoff point, although without statistical significance, possibly due to the small sample size. Further studies are needed for subsequent validation of this innovative index.