Less increase of BNP and NT-proBNP levels in obese patient with decompensated heart failure: interpretation of natriuretic peptides in obesity.

OBJECTIVE

Plasma brain natriuretic peptide (BNP) is a useful adjunct to diagnose and monitor patient with heart failure, but there are comorbidities such as chronic kidney disease or chronic pulmonary disease, which influence the interpretation of BNP levels.

PATIENT

We present a case of a young and very obese patient (body mass index [BMI] 72.6 kg/m(2)), who was presented with acute global heart decompensation. Echocardiography revealed a dilated left ventricle with an ejection fraction of 20% by global distributed heart with enlarged right heart caves. Computed tomography and X-ray demonstrated an extreme cardiomegaly with cardio-thoracic ratio of 0.71. Remarkably, laboratory measurements revealed only a slight elevated concentrations of brain natriuretic peptide (BNP) (443.2 pg/ml) and his inactive component NT-proBNP (1710 pg/ml). Despite maximized heart care clinical condition of the patient aggravated continuously so that the patient died after 6 days because of heart insufficiency.

CONCLUSION

Obese patients (body mass index [BMI] >30 kg/m(2)) with any given severity of heart failure obviously express lower levels of BNP. Until now, the cause for this phenomenon is unclear. Therefore caution should be exercised in interpreting BNP levels in such patients.