Echocardiographic Nomogram Model: A Tool for Assessing Cardiac Involvement in Patients With Systemic Amyloidosis.

Objectives: Cardiac involvement is significantly relevant to a poor prognosis in patients with systemic amyloidosis, often leading to adverse outcomes. The objective of this study was to develop a diagnostic model for cardiac amyloidosis (CA) in primary light chain amyloidosis (pAL) to facilitate early detection and improve prognostic evaluation.

Methods: In this retrospective study involving 72 patients with primary pAL amyloidosis (51 with cardiac involvement), we systematically employed cardiac magnetic resonance imaging (CMR) for cardiac assessment. CA diagnosis was confirmed histologically via noncardiac tissue biopsy, positive for light chain systemic amyloidosis. To dissect the risk factors for cardiac involvement, we applied both univariate logistic regression and a random forest algorithm. Subsequently, the findings from these analyses informed the construction of a predictive nomogram. We rigorously evaluated the nomogram's performance using receiver operating characteristic curve analysis, calibration curve assessment, and decision curve analysis.

Results: The nomogram model included relative wall thickness (RWT), the ratio of mitral peak flow velocity in early diastolic (E wave) to the pulsed tissue Doppler imaging-derived early diastolic peak velocity (e' wave) at the interventricular septal mitral annulus (E/e' sep), ejection fraction to peak systolic global longitudinal strain ratio (EFSR) and right ventricular fractional area change (RV FAC). The model exhibited good diagnostic performance, with an area under the ROC curve of 0.85 (95% CI, 0.75-0.92), a sensitivity of 80.4% (95% CI, 66.9%-90.2%), and a specificity of 85.7% (95% CI, 63.7%-97.0%).

Conclusions: The nomogram provided a noninvasive and effective means of assessing cardiac involvement in systemic amyloidosis, offering a valuable aid for clinical decision-making and patient management.