Assessment of Natriuretic Peptides: The Heart Should Be Evaluated as a Whole

Abstract

Dear Editor, We read with great interest the article by Rodrigues et al1 entitled Right Ventricular Assessment by Tissue-Doppler Echocardiography in Acute Pulmonary Embolism, which was published of the Arquivos Brasileiros de Cardiologia. The authors1 aimed to evaluate the right ventricular (RV) systolic function using two-dimensional tissue Doppler echocardiography in patients with acute pulmonary embolism (PE) and to analyze its correlation with atrial natriuretic peptide (BNP) levels. The authors concluded that increased BNP levels (≥ 50 pg/mL) were associated with a higher prevalence of RV systolic dysfunction in patients with PE. Although the current article is well-managed, and we commend the authors for the detailed and valuable information that they have provided, some comments may be beneficial. Natriuretic peptides are predominantly secreted by cardiac myocytes in response to myocardial stretch induced by volume load2,3. They act to increase natriuresis and decrease vascular resistance, thereby decreasing blood volume, systemic blood pressure and afterload2. Atrial natriuretic peptide is synthesized primarily by the atrial myocardium. Natriuretic peptide concentrations are associated with atrial and atrial appendage functions as well as with the severity of mitral and aortic valve regurgitation and stenosis2-5. In addition, natriuretic peptide levels have been shown to be higher in hyperthyroid, hypertensive and obese patients, due to the direct stimulatory effect of thyroid hormones, left ventricular hypertrophy and increased afterload and insulin resistance, respectively5. In conclusion, although natriuretic peptide levels are associated with ventricular functions, other factors which could increase peptide levels should be assessed. If information on thyroid hormone levels, body mass indexes and mean blood pressure levels of patients was provided, as well as on the assessment of mitral and aortic valves (regurgitation and stenosis) and of atrial volumes (left and right), which could alter the results, the study could be more valuable and the information obtained from the study could add more consistency to the results.