Prognostic value of CMR-derived right ventricular global longitudinal strain in light-chain cardiac amyloidosis

Abstract

Cardiac involvement determines prognosis in light-chain (AL) amyloidosis. The incremental prognostic role of right ventricular (RV) deformation assessed by cardiac magnetic resonance (CMR) remains incompletely defined. In a prospective cohort of 100 patients with AL amyloidosis, baseline clinical, biomarker, echocardiographic and CMR parameters were collected. The primary endpoint was all-cause mortality (72-month follow-up). Cox regression assessed associations with outcome. Model discrimination was evaluated using Harrell’s C-index. ROC analysis identified an optimal RV global longitudinal strain (GLS) cut-off, followed by Kaplan–Meier analysis. During follow-up, 25 deaths occurred. Baseline CMR and echocardiographic characteristics stratified by survival status (Table 1). CMR-derived RV GLS was the strongest imaging predictor of mortality (HR 1.17 per 1% worsening; 95% CI 1.08–1.28; p<0.001) and remained independently associated with outcome after adjustment for biomarkers and Mayo stage. Addition of RV GLS improved discrimination (C-index 0.595 to 0.710). ROC analysis demonstrated good accuracy (AUC 0.74, 95% CI 0.63–0.85; Figure 1A), and an RV GLS cut-off of −16.4% identified patients with significantly reduced survival (log-rank p<0.001; Figure 1B). Echocardiographic RV GLS showed limited discrimination (AUC 0.62; p=0.16) and modest agreement with CMR (ICC 0.43). CMR-derived RV GLS is an independent predictor of mortality and provides incremental prognostic value beyond Mayo staging in AL amyloidosis.