Echocardiographic reference ranges for non-invasive myocardial work indices in heart transplant patients

Abstract Background Non-invasive myocardial work (MW) is a relatively novel echocardiographic method with increasing fields of application. Normal reference ranges of MW indices in a healthy population have already been determined but these may differ in patients who have undergone a heart transplant (HTX). Purpose To obtain the reference ranges for 2D echocardiographic indices of MW for HTX patients and to compare them with the results of the EACVI NORRE study regarding healthy volunteers. Methods All consecutive HTX patients admitted at our Institution under Day Hospital regimen from September 2019 to May 2022 who performed endomyocardial biopsy (EMB) were considered. Patients with echocardiographic exam or brachial artery cuff pressure unavailability, history of rejection, history of coronary artery vasculopathy (CAV) and either acute cellular rejection (ACR) or acute antibody-mediated rejection (AMR) at EMB were excluded. Non-invasive MW calculation through Speckle-tracking Echocardiography (STE) was retrospectively performed for included patients. Further, MW analysis results were compared to those from the EACVI NORRE study. Results Out of 176 HTX patients who had performed EMB and had available echocardiographic and blood pressure data, 35 patients were excluded because of history of rejection, 4 patients because of history of CAV and 55 patients because of either ACR or AMR at EMB. Therefore, study population consisted of 82 HTX patients (68.3% male, median age 53 (46 – 62) years). Median age from HTX was 5 (2 – 22) months. Mean global work efficiency (GWE, 84 ± 8 %), global work index (GWI, 1447 ± 409 mmHg%), global constructive work (GCW, 2067 ± 423 mmHg%) and median global wasted work (GWW, 310 (217 – 499) mmHg%) did not differ between sex categories (p-value > 0.05). Each of these indices significantly differed from those reported in the EACVI NORRE study (p-value < 0.001), with lower GWI, GCW, GWE and higher GWW in the HTX population. Conclusion This study provides reference ranges for non-invasive MW indices in a HTX population free from transplant-related complications which are different from those regarding a population of healthy volunteers.Table 1