Right ventricular free wall longitudinal strain as determined by speckle tracking echocardiography is a noninvasive predictor of acute cellular rejection in adult heart transplantation

Abstract

Background Acute cellular rejection (ACR) is a major complication after heart transplantation. Endomyocardial biopsy (EMB) remains the gold standard for its diagnosis, but with concerning complications. We evaluated the usefulness of speckle tracking echocardiography (STE) and the biomarkers for detecting ACR after heart transplantation. Methods We prospectively studied 60 transplant patients with normal left and right ventricular systolic function who underwent EMB for surveillance sixth months after transplantation. Sixty age- and sex-matched healthy individuals constituted the control group. Conventional echocardiographic parameters left ventricular global longitudinal, radial and circumferential strain (LV-GLS, LV-GRS and LV-GCS, respectively), left ventricular systolic twist (LV-twist) and right ventricular free wall longitudinal strain (RV-FWLS) were analyzed just before procedure. We also measured biomarkers at the same moment. Results Of 60 patients included, 17 (28%) had severe ACR (grade ≥ 2R) and 43 (72%) had no significant ACR (grade 0–1R). Absolute values of LV-GLS, LV-twist and RV-FWLS were lower in transplant patients with ACR degree ≥ 2 R compared with those without ACR (12.5% ± 2.9 vs 14.8% ± 2.3, p = 0.002 ; 13.9° ± 4.8 vs 17.1° ± 3.2, p = 0.048; 21.4%± 3.2 vs 16.6% ± 2.9, p < 0.001; respectively), while no differences were observed in both LV-GRS or LV-GCS. All these parameters were lower in transplant group without ACR than in non-transplant controls, except for LV-twist. Cardiac troponin I levels were significantly higher in patients with significant ACR than in patients without significant ACR [0.19 (0.09–1.31) vs. 0.05 (0.01–0.18), p = 0.007]. In multivariate analysis, RV-FWLS was the only independent predictor of ACR (odds ratio = 0.57; 95% CI = 0.40–0.81; p = 0.02). RV-FWLS < 18.0% had an accuracy of 85% to predict ACR. Conclusion Heart transplant patients have altered left ventricular dynamics compared with non-transplant individuals. RV-FWLS was the only independent predictor of ACR after heart transplantation and should be considered a valuable noninvasive screening parameter for its detection.