Background: Cardiac involvement in systemic amyloidosis irrespectively of etiology has prognostic value. However, little is known about the different features of cardiac involvement in patients with light chain (AL) and transthyretin-related (TTR) amyloidosis.
Purpose: To evaluate different kind of cardiac involvement in patients with AL and TTR amyloidosis by noninvasive methods.
Methods: The study population included 120 patients (81 male, 39 female; mean age: 68.6±10.4 years) with amyloidosis. Among them AL amyloidosis in 102 subjects and TTR amyloidosis in 18 subjects. Plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP), troponin and creatinine levels were measured in all patients. All pts were underwent to transtoracic echocardiography with systolic and diastolic function evaluation, left ventricular (LV) wall thickness measurement and LV mass calculation. The results were analysed by using SPSS and descriptive statistics are presented as percentages, means and SDs. Univariate analysis for group comparisons were performed using Student's t test and Mann–Whitney U tests, where appropriate. The degree of association between clinical and laboratory variables were determined using the Pearson's correlation coefficient.
Results: Comparative analysis between groups with TTR and AL amyloidosis showed no statistical differences in age (64.8±16.1 years vs. 69.1±9.2 years, p=ns), left ventricular EF (49.2±10.3% vs. 54.4±12.3%, p=ns), and E/e' ratio (17.1±7.1 vs. 15.3±6.7). Patients with TTR amyloidosis in comparison with AL amyloidosis group were characterised by lower troponin I level (0.08±0.09 ng/ml vs. 0.35±0.97 ng/ml; p=0.035); lower pooled median serum NT-proBNP level [25th; 75th percentile]: 1194.0 [173.0; 2807.0] ng/l vs. 4425.5 [883.0; 13996.3] ng/l; p=0.02); lower creatinine level (0.98±0,33 mg/dl vs. 1.41±0.73 mg/dl; p=0.05) and increased LV wall thickness (14.5±3.6 mm vs. 18.0±3.1 mm, p=0.02). In both groups the correlation between NT-proBNP level and E/e' ratio was statistically significant (r=0.338, p=0.04).
Conclusion: Patients with TTR amyloidosis have increased LV thickness with paradoxically lower level of NT-proBNP in comparison with AL amyloidosis group. Serum NT-proBNP correlates with degree of diastolic dysfunction in patients with amyloidosis and related to impaired diastolic function in these patients.