Characteristics and clinical significance of myocardial work in cardiac light-chain amyloidosis: pressure-volume loop analysis based on cardiac magnetic resonance
S Liang, K Wan, Q Deng, J Guo, J Li, K Bi, D Li, J Chen, J Sun, Q Zhang, Y Han, Y ChenAbstract
Background
Left ventricular pressure-volume (PV) loop analysis via cardiovascular magnetic resonance (CMR) offers noninvasive assessment of cardiac thermodynamic efficiency. We aimed to evaluate the clinical relevance and prognostic value of noninvasive PV-loop parameters in patients with cardiac light-chain (AL) amyloidosis.
Methods
This prospective, single-center study enrolled patients with cardiac AL amyloidosis (AL-CA) who underwent CMR between November 2011 and September 2023. PV-loop parameters were derived from CMR cine images and brachial blood pressure. The primary endpoint was all-cause mortality. Cox regression analysis assessed associations between PV-loop parameters and outcomes, with incremental prognostic value evaluated using C statistics and likelihood ratio tests.
Results
The single-center, prospective study included 267 consecutive AL-CA patients (mean age 58.8 years±9.8 [SD]; 168 [62.9%] males) and 30 healthy controls with similar age and sex (mean age, 59.9±year 8.2 [SD]; 15 [50%] males). Work efficiency (WE) showed moderate to strong correlations with cardiac function, volumes, decease activity and amyloid burden (all P < 0.01). During a median follow-up of 42 months (IQR: 35-49), 185 patients (69.3%) died. Univariable Cox analysis showed AL-CA patients with WE < 72.2% were at higher mortality risk (hazard ratio 2.45, 95% CI: 1.68-3.57; P < 0.001). After multivariable adjustment, WE < 72.2% remained independent prognostic factor. The integration of WE with Mayo 2004 stage enhanced prognostic discrimination and calibration (C-statistic 0.65, χ² 36.28) relative to Mayo 2004 stage alone (C-statistic 0.58, χ² 25.79), and performed comparably to the combination of extracellular volume fraction (ECV) with Mayo 2004 stage (C-statistic 0.66, χ² 44.49).
Conclusion
Myocardial work impairment can be detected early, even with preserved LVEF. WE derived from noninvasive and non-enhanced PV-loop analysis via CMR, not only reflects disease severity as quantified by ECV, but also serves as a complementary marker to ECV in risk stratification.GRAPHIC ABSTRACT