B-TYPE NATRIURETIC PEPTIDE IN LYMPHEDEMA

Abstract

Lymphedema often responds tocompression therapy which can also causeundesirable cardiac overload if heart failurecoexists. We hypothesized that the biomarkerB-type natriuretic peptide (BNP) can be usedto screen lymphedema patients for undetectedcardiac dysfunction. We studied unselectedconsecutive patients with lymphedema todetermine their BNP status and comparedthese data with those obtained from healthysubjects without known cardiovasculardiseases. Out of a total of 305 subjects withlymphedema screened, 102 (33%) consented totake part in this study. The majority (87%)were female with a mean age of 60.5 ± 13.2(SD) years, and 47% had just lower limbswelling. The groups were equally dividedbetween cancer and non-cancer relatedcauses. There were 45 females and 4 malesunder 60 years old, and 44 female and 9 malepatients over 60 years old. Median (IQR) BNP(ng/L) were as follows: <60 years females =17.9 (15.2) (median [RR: 3 - 64] and males =12.4 (14.7) [RR: 0.2 - 44], >60 years females =35.8 (57.9) [RR: 2 -247)] and males = 47.2(44.1) [RR: 2 - 238]. For this population, theBNP concentration 100 ng/L was adopted asthe value to exclude heart failure. Using thisdefinition, 7 lymphedema subjects had BNPconcentrations of 120 (19.8) ng/L, and all werefound to have cardiac abnormalities onechocardiography. This study demonstratedthat 93% of unselected subjects with lymphedema had BNP concentrations thatexclude a diagnosis of heart failure. Thosesubjects with elevated BNP were found onsubsequent echocardiography to have cardiacabnormalities. The use of a BNP assay is ofpotential value in screening patients who aremore likely to have cardiac failure. Indicativefactors include bilateral leg swelling, over theage of 50 years, breathlessness, where there isno known cause for the swelling. A BNP assayusing a BNP concentration threshold of 100ng/L (29 pmol/L) will identify those patientswho require more detailed investigations.