Myocardial work in light-chain and transthyretin-related amyloidosis with preserved ejection fraction: a cardiac magnetic resonance study
S Liang, J Chen, Q Deng, D Li, K Wan, K Bi, J Sun, Q Zhang, Y Han, Y ChenAbstract
Objectives
To investigate pressure-volume loop (PV-loop) changes by cardiac magnetic resonance (CMR) imaging in cardiac amyloidosis (CA) patients with preserved left ventricular ejection fraction (LVEF), and to assess PV-loop parameters' potential as CA subtype differential diagnostic markers.
Methods
Between May 2017 and September 2023, 100 confirmed CA patients (14 transthyretin [ATTR-CA] and 86 light-chain [AL-CA]) and 40 age- and sex-matched healthy controls (HCs) were prospectively enrolled. PV-loop parameters were derived from CMR cine images and brachial blood pressure. Clinical and CMR parameters were compared between CA patients and HCs, as well as between CA subtypes. The correlations between PV-loop parameters and clinical and imaging parameters were assessed. Furthermore, the differential diagnostic performance of these PV-loop parameters was evaluated using the area under the receiver operating characteristic curve (AUC). Bootstrapping was performed 2000 times for internal validation.
Results
Compared to HCs, CA patients showed significantly lower stroke work index, potential energy index (PEI), and work efficiency (all P < 0.001). AL-CA patients had higher NT-proBNP levels (2358 [IQR 903.25, 5559] vs. 810 [IQR 269, 1136.01] pg/mL, P = 0.002) and lower PEI (0.13 [IQR 0.07, 0.15] vs. 0.15 [IQR 0.13, 0.19] J/m², P = 0.025) than ATTR-CA patients. NT-proBNP (β = –1.94, OR = 0.14, 95%CI: 0.03-0.64, P = 0.016) and PEI (β = 0.20, OR = 1.23, 95% CI: 1.07-1.44, P = 0.007) were independent predictors for AL-CA vs. ATTR-CA differentiation, and combining these two parameters enhanced the diagnostic performance (bootstrapping AUC 0.847).
Conclusion
By providing pathophysiological insights into the distinctions of AL-CA and ATTR-CA, PV-loop parameters could serve as a complementary, contrast-free approach for differential diagnosis.graphic abstract