Objectives: This paper will describe associations between plasma natriuretic peptide levels and the severity and symptoms of mitral regurgitation (MR).
Background: A biochemical test that assisted grading of the severity of MR and the interpretation of symptoms would be of clinical value.
Methods: Forty-nine patients with isolated MR and left ventricular (LV) ejection fractions (EFs) of >55% underwent transthoracic echocardiography, assessment of symptoms, and measurement of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and its amino-terminal portion, N-BNP.
Results: The level of each natriuretic peptide rose with increasing severity of MR and with increases in left atrial (LA) dimensions (p < 0.001 for all comparisons), but no significant correlation existed between any natriuretic peptide and the LV dimensions or EF. Natriuretic peptide levels were higher in symptomatic MR (n = 16, BNP geometric mean 16.9 [95% confidence interval (CI) 13.3 to 21.4] pmol/l) compared with asymptomatic MR (n = 33, BNP 7.1 [95% CI 6.0 to 8.4] pmol/l, p < 0.001), and higher in asymptomatic MR than in normal controls (n = 100, BNP 5.3 [95% CI 4.8 to 5.8] pmol/l, p < 0.0001). These differences were similar for N-BNP and ANP and remained statistically significant (p < 0.05) after adjustment for echocardiographic measures of LV function and severity of MR. Both the sensitivity and the specificity for symptoms for the natriuretic peptides (area under receiver-operator characteristic curve for BNP = 0.90, N-BNP = 0.89, ANP = 0.89) were similar to the MR score (0.88) and greater than for LA dimension (0.81), vena contracta width (0.82), and LV end-systolic dimension (0.63).
Conclusions: Plasma natriuretic peptides levels increase with the severity of MR and are higher in symptomatic compared to asymptomatic patients, even when LV EF is normal.