Assessment of disease severity and outcome in patients with systemic light-chain amyloidosis by the high-sensitivity troponin T assay.

Cardiac biomarkers provide prognostic information in light-chain amyloidosis (AL). Thus, a novel high-sensitivity cardiac troponin T (hs-TnT) assay may improve risk stratification. hs-TnT was assessed in 163 patients. Blood levels were higher with cardiac than renal or other organ involvement and were related to the severity of cardiac involvement. Increased sensitivity was not associated with survival benefit. Forty-seven patients died during follow-up (22.3 ± 1.0 months). Nonsurvivors had higher hs-TnT than survivors. Outcome was worse if hs-TnT more than or equal to 50 ng/L and best less than 3 ng/L. Survival of patients with hs-TnT 3 to 14 ng/L did not differ from patients with moderately increased hs-TnT (14-50 ng/L), but was worse if interventricular septum was more than or equal to 15 mm. Discrimination according to the Mayo staging system was only achieved by the use of the hs-TnT assay, but not by the fourth-generation troponin T assay. Multivariate analysis revealed hs-TnT, NT-proBNP, and left ventricular impairment as independent risk factors for survival. hs-TnT and NT-proBNP predicted survival, even after exclusion of patients with impaired renal function. Plasma levels of the hs-TnT assay are associated with the clinical, morphologic, and functional severity of cardiac AL amyloidosis and could provide useful information for clinicians on cardiac involvement and outcome.

Improvement of risk assessment in systemic light-chain amyloidosis using human placental growth factor.

BACKGROUND: Vascular amyloid deposition is common in light-chain amyloidosis resulting in endothelial dysfunction. Human placental growth factor (PlGF), a member of the vascular endothelial growth factor family was found to be altered in diverse pathological conditions, e.g. endothelial dysfunction. This study evaluated the clinical role of PlGF in light-chain amyloidosis. METHODS: PlGF (cobas-PlGF, Roche Diagnostics, Mannheim, Germany) was analyzed in 125 consecutive patients with AL and correlated with diverse clinical parameters including mortality. RESULTS: Kidney (n = 76) and heart (n = 57) were predominantly affected by amyloid deposition. Median PlGF was 26.3 (21.1-42.1) ng/L, NT-proBNP 3649 (1124-8581) pg/mL, and hs-TnT 42 (21-107) ng/L. PlGF increased with number of organs involved and with deterioration of renal function. A significant correlation of PlGF with hs-TnT (ρ = 0.306; p = 0.0007) and NT-proBNP (ρ = 0.315; p = 0.0006) was observed, but no correlation was observed with clinical, echocardiography, and electrocardiography parameters of cardiac involvement. In this cohort 1-year all-cause mortality was 19.2 %. The best cutoff discriminating survivors and non-survivors was 28.44 ng/L (sensitivity 66.7 %; specificity 78.1 %). A three-step risk model including hs-TnT and NT-proBNP revealed a better discrimination if patients at intermediary risk were additionally stratified by PlGF. Net reclassification index was 37.2 % (p = 0.002). Multivariate analysis revealed PlGF, difference of involved and uninvolved light chain, number of organs involved and risk class according to troponin T and NT-proBNP as independent predictors of mortality. CONCLUSION: Plasma PlGF values in AL are invariably associated with the number of involved organs, but not with clinical, echocardiography, and electrocardiography parameters of cardiac involvement. PlGF provide useful information for risk stratification of patients at intermediary risk according to hs-TnT and NT-proBNP.

Osteopontin: a novel predictor of survival in patients with systemic light-chain amyloidosis.

BACKGROUND: Troponin-T (cTnT) and NT-proBNP provide prognostic information in light-chain amyloidosis (AL). Thus, these biomarkers are widely used in clinical routine for risk stratification. Recently, plasma level of osteopontin (OPN), a secreted phosphoglycoprotein expressed by a variety of cell types, has been reported as a risk predictor in various cardiovascular diseases. METHODS: OPN was determined retrospectively in 150 consecutive patients newly diagnosed with AL amyloidosis. All patients were evaluated according to a routine protocol including electrocardiography, echocardiography and laboratory testing. RESULTS: Mean OPN was 591 ± 37 ng/mL. Cardiac involvement was established in 83 (55.3%). Median OPN plasma level were associated with number of organs involved, renal function, eligibility for high-dose melphalan chemotherapy and autologous stem cell transplantation, and severity of cardiac amyloidosis. Median follow-up was 19.2 months. 1-year all-cause-survival was 83.4%. The cut-offs discriminating 1-year all-cause-mortality for NT-proBNP, troponin T, and OPN were 2544 ng/L, 0.035 µg/L, and 426.8 ng/mL, respectively. Outcome was worse in patients with biomarkers above the individual ROC derived cut-off. A significant improvement of survival was observed in patients with cTNT >0.035 µg/L or NT-proBNP >2544 ng/L and OPN below ROC-derived cut-off of 426.8 ng/mL as compared to patients with OPN above 426.8 ng/L. No further discrimination was achieved by OPN in the cohorts of low troponin T or low NT-proBNP, respectively. Separate multivariate models identified OPN (cut-off 426.8 ng/mL) and troponin T (cut-off 0.035 µg/L) as independent predictors of all-cause-mortality. CONCLUSIONS: These data demonstrated that OPN appears to be a valuable marker in the clinical routine for evaluation of patients with AL amyloidosis, especially if it is used in combination with cTNT and/or NT-proBNP.