Background symptomatic clinically cardiac involvement in PM/DM is rare but seems to be one of the most important cause of death1. High Nt-proBNP levels are commonly considered a marker of heart failure and were recently detected in rheumatic diseases without clinically evident heart involvement. Some authors hypothesize that high Nt-proBNP values can be likely considered indicators of subclinical cardiac damage2.
Objectives evaluation Nt-proBNP levels in a group of patients with PM/DM compared with normal healthy subjects.
Methods we enrolled consecutive PM/DM patients (Bohan and Peter criteria) hospitalized in our Unit from 2006 to 2010; in all of them we measured Nt-proBNP serum levels (normal values <125 pg/ml) and performed an echocardiographic evaluation. We excluded patients with reduced left ventricular function (EF<55%), kidney failure, ischemic cardiomyopathy, arrhythmias and clinical history for other cardiovascular diseases. The most common cardiovascular risk factors as hypertension, hypercholesterolemia, diabetes, smoke were evaluated.
Results we enrolled 34 patients (21 PM and 13 DM); 26 female and 8 male, mean age 54 years [24-76]; mean disease duration 24 month [0-24], and a group of 32 healthy subjects, comparable for age and sex.
Mean value of Nt-proBNP levels was 352 pg/ml in PM/DM patients (440 pg/ml in PM, 217 pg/ml in DM) and 51 pg/ml in control group (p<0.001).
We also subdivided PM/DM and the control group according to the presence of cardiovascular risk factors and compared Nt-proBNP levels in 4 groups. Data are reported in the table
In PM/DM patients, the presence of cardiovascular risk factors increased widely Nt-proBNP levels (536 vs 103 pg/ml; p=0.006) while in the controls group the values were only lowly increased (60 vs. 41).
In the subgroups without cardiovascular risk factors (2 and 4), Nt-proBNP mean values, even if in the normal range, were higher in PM/DM group than in healthy subjects (p=0.074). In presence of cardiovascular risk factors, Nt-proBNP mean values were higher in the subgroup 1 compared with subgroup 3 (p=0005).
Conclusions This data suggests that, even without evident cardiac involvement, in presence of cardiovascular risk factors, patients with PM/DM have higher Ntpro-BNP levels and probably an higher risk to develop heart involvement.
This intriguing aspect needs to be studied in detail in a larger amount of patients and controls, to establish the weight of the single cardiovascular risk factor.
Lundberg I: The heart in dermatomyositis and polymyositis. Rheumatology (Oxford) 2006; 45 Suppl 4: iv 18-21.
Giannoni A, Tani C et al: When the heart is burning: amino-terminal pro-brain natriuretic peptide as an early marker of cardiac involvement in active autoimmune rheumatic disease. Int J Cardiol. 2011;148(2):161-7.
Disclosure of Interest None Declared
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