Comparison of lambda and kappa light-chain cardiac amyloidosis in Polish patients diagnosed in cardiology department
Authors: Szczygiel J.A , Michalek P , Drozd-Sokolowska J , Ziarkiewicz M , Bilinska Z.T , Gawor M , Mazurkiewicz L , Ojrzynska N , Legatowicz-Koprowska M , Walczak E.M , Waszczuk-Gajda A , Dwilewicz-Trojaczek J , Jedrzejczak W.W , Basak G.W , Grzybowski J 
Published: November 2020

Abstract

Background
Lambda (λ) and kappa (κ) types of light-chain amyloidosis (AL amyloidosis) are believed to have a similar prognosis. Data on the comparison of these two types of cardiac amyloidosis is scanty.

Objectives
The aim of the study was to investigate wether lambda light-chain cardiac amyloidosis indicates worse prognosis than the kappa variety.

Methods
The initial analysis covered all consecutive pts with cardiac AL amyloidosis diagnosed in the cardiology department from August 2011 to August 2019. Diagnosis was confirmed by increased serum free light-chains and positive tissue biopsy. Amyloid type was identified using immunohistochemical reactions. Blood pressure and heart rate (HR) were measured on admission. The difference between involved and uninvolved serum free light chains (dFLC), NT-proBNP, high-sensitivity troponin T (hs-TnT), creatinine, potassium, albumin and total protein were measured. During echocardiography, tissue Doppler imaging was used to assess early lateral (e' lat) and septal mitral annulus velocities and longitudinal myocardial velocities of ventricles. Standard parameters were measured. The presence of pleural effusion was assessed in chest X-ray.

Results
Sixty-four pts were diagnosed with AL amyloidosis. Four pts were excluded from the final analysis due to ambiguous amyloid typing. Median (interquartile range, IQR) age was 61 (52–67) yrs. Median (IQR) dFLC was 19.9 (5.5–50.6) mg/dL. Median NT-proBNP and hs-TnT concentrations were 4948 (2251–10206) pg/ml and 77 (39–139) ng/l, respectively. Forty-four pts had a λ type AL amyloidosis (73.3%). There were significant differences (p&lt;0.05) between the λ and the κ groups in regard to: HR (80 vs. 73.5 BPM), systolic blood pressure (102 vs. 117 mmHg), serum creatinine (88 vs. 116 umol/L) and potassium (4.4 vs. 4.9 mmol/L), e' lat (5 vs. 7.5 cm/sec), left ventricular end-diastolic diameter (LVEDD, 42 vs. 46 mm), right ventricular end-diastolic diameter (RVEDD, 35 vs. 40 mm) and right ventricular wall thickness (8 vs. 6 mm). Pleural and pericardial effusions were more frequent in the λ group (59% vs. 19% and 80% vs. 44%, respectively) according to Fisher's exact test (p&lt;0.05). Median (IQR) survivals for the λ and the κ groups were 3 (2–9) and 16 (5.5–22) months, respectively (p=0.03). The Kaplan-Meier curves analysis showed a trend towards worse survival of the λ group (Log rank test, p=0.08).

Conclusions
Cardiologists should be aware that lambda light-chain cardiac amyloidosis may indicate shorter survival than the kappa variety, although kappa AL amyloidosis may be associated with worse kidney function. Further research would be worth considering.
Kaplan-Meier curves, Time (months)

Funding Acknowledgement
Type of funding source: Public grant(s) – National budget only. Main funding source(s): Institute of Cardiology