# Right Atrial Contraction Strain Is Associated With Clinically Significant Cellular Rejection in Patients After Heart Transplantation

## TL;DR

Right atrial contraction strain measured by echocardiography is linked to significant cellular rejection in heart transplant patients.

## Contribution

This study identifies right atrial contraction strain as a novel indicator for detecting cellular rejection after heart transplantation.

## Key findings

- Right atrial contraction strain (RASct) cut-off of −9.3% had 100% sensitivity and 79% specificity for ≥ moderate acute cellular rejection.
- RASct was significantly associated with ≥ moderate acute cellular rejection (OR 1.55, 95%CI 1.18–2.43).
- Findings were validated in a separate group of 23 heart transplant patients.

## Abstract

Strain echocardiography (SE) may be used for surveillance in patients after heart transplantation (HTx); however, data on atrial strain are lacking. We aimed to compare the significance of ventricular and atrial strain with respect to an associated acute cellular rejection (ACR). Patients who underwent an endomyocardial biopsy (EMB) within 1 year after HTx were eligible for this retrospective analysis. The relationship between SE and ACR was assessed. EMB results of 52 patients (median age, 53 years; 63% male) at a median of 181 days post-HTx were identified. Mild ACR was present in 19 patients and ≥ moderate ACR in 6 patients. ACR ≥ moderate was associated with right ventricular free wall strain (OR 1.20, 95%CI 1.02–1.46, P = 0.04) and right atrial contraction strain (RASct; OR 1.55, 95%CI 1.18–2.43, P = 0.01). The RASct cut-off value of −9.3% had a sensitivity of 100% and a specificity of 79% for ≥ moderate ACR. None of these associations were observed for left ventricular or left atrial strain. A validation analysis was performed on another group of 23 HTx patients, which yielded similar results with regard to the specified RASct cut-off value. Our comprehensive strain analysis confirmed the association between reduced right ventricular strain and ACR and further identified robust associations between RASct and ACR. Right atrial strain analysis may be a promising method for excluding subclinical ACR after HTx.

Infographic titled "Right atrial contraction strain is associated with clinically significant cellular rejection in patients after heart transplantation." It includes study details on heart transplant recipients undergoing endomyocardial biopsies. Illustrations show donor heart and histopathology. A graph compares the probability of non-rejection over time with a significant p-value of less than 0.0001. Echocardiogram images depict strain echocardiography of the right atrium, labeled for rejection status. Notes emphasize a cutoff value of minus 9.3 percent for detecting rejection. The study is attributed to Rieth AJ et al., Transplant International 2025.