Peptídeos natriuréticos no prognóstico de insuficiência cardíaca congestiva

Abstract

Decompensated congestive heart failure (CHF) is a clinical syndrome often characterized by elevated left ventricular fi lling pressures (LVEDP). Therapy for decompensated CHF aims at normalizing fi lling pressures and thereby improves both symptoms and outcomes. However, therapy guided by direct measurements of fi lling pressure is not practical in most patients, focusing attention on non-invasive surrogate measures of LVEDP for tailoring of heart failure therapy.Natiruretic peptide levels (NP) are closely correlated with LVEDP, which is consistently elevated in decompensated heart failure. In the absence of acute mitral regurgitation and fl ash pulmonary edema, and in the presence of volume overload, NP levels are a useful indication of pulmonary capillary wedge pressure (PCWP). In a study by Kazenegra et al, patients admitted for decompensated CHF had BNP levels and hemodynamic measurements taken every 2 hours for the fi rst 24 hours and every four hours for the next 24-48 hours. PCWP showed a decrease from 33 to 25 mmHg over the fi rst 24 hours, while BNP levels decreased from 1472 to 670 pg/ml. However, no change in BNP was noted in patients with end-stage heart failure, even as wedge pressures dropped 1 .In the study by Pereia-Barretto et al 2 , in this issue (Serum NT-proBNP levels are a prognostic predictor in patients with advanced heart failure), 105 subjects with poor LV function and signifi cant symptoms were evaluated in terms of baseline NP levels and subsequent mortality. Natriuretic peptide levels, in this case, NT-proBNP, were strong predictors of 90 day survival. Despite the limitations of the study design (patient heterogeneity, paucity of events, and absence of serial sampling), the paper adds to a growing body of evidence that natriuretic peptides, measured in the decompensated period, provide signifi cant risk stratifi cation.NP levels are useful tools in the assessment of patients even prior to hospitalization. The Rapid Emergency Department Heart Failure Outpatient Trial (REDHOT) examined the relationship between perceived severity of disease by physicians and severity as indicated by BNP levels. Patients who were discharged from the hospital had higher BNP levels than those admitted for treatment.The median BNP level for discharged patients was 976 pg/ml, compared with a mean BNP of 766 pg/ml for patients who were admitted to the hospital. Patients with BNP levels less than 200 pg/ml had an excellent prognosis, with a mortality of 0% at 30 days and only 2% at 90 days 3 .The inclusion of NPs in clinical decision-making has been shown to be cost effective and to improve quality of care in the emergency and hospital settings. The BASEL study in Switzerland explored the cost effectiveness of using the BNP test as an adjunct to the standard clinical tools. Patients enrolled in the study were randomized to one of two groups-utilize BNP blood testing upon arrival in the ED and throughout hospitalization and standard care group without using BNP levels. Patients who received a BNP test upon presen...