Usefulness of the brain natriuretic peptide to atrial natriuretic peptide ratio in determining the severity of mitral regurgitation

Abstract

I n chronic mitral regurgitation (MR), increased preload and reduced afterload due to unloading from the left ventricle (LV) into the left atrium (LA) leads to compensatory dilation of the LV and facilitates LV ejection. Although this response initially maintains cardiac output, myocardial decompensation eventually results in heart failure symptoms and an increased risk of sudden death. In addition, backflow into the LA results in enlargement of the LA, atrial fibrillation and elevated pulmonary pressures. In some patients, LV contractility is irreversibly impaired in the absence of symptoms (1-3). Thus, deferring surgical intervention often leads to irreversible postoperative LV dysfunction. Valve replacement or valvuloplasty is essential before the myocardial damage becomes irreversible.Early valvuloplasty conducted when heart failure is mild has been reported to improve prognosis (4). In clinical practice, however, it remains difficult to decide the timing of surgery defined by mild heart failure symptoms and preserved cardiac function.Some reports have shown that preoperative LV function (LV end-diastolic diameter [LVDd], LV end-systolic diameter BACKGROUND: Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels were characterized in subjects with mitral regurgitation (MR). METHODS: Sixty-two cases of moderate or severe chronic MR were studied. The blood levels of neurohormonal factors were stratified by the known MR prognostic factors of New York Heart Association (NYHA) functional class, left ventricular end-diastolic diameters, left ventricular end-systolic diameter (LVDs), ejection fraction (EF), left atrial diameter and presence of atrial fibrillation (AF). RESULTS: ANP levels were higher in NYHA class II and lower in classes I and III/IV (P=0.0206). BNP levels were higher in NYHA class II than class I (P=0.0355). The BNP/ANP ratio was significantly higher in NYHA classes II and III/IV than in class I (P=0.0007). To differentiate between NYHA classes I/II and III/IV, a cut-off BNP/ANP ratio of 2.97 produced a sensitivity of 78% and specificity of 87%. Compared with subjects in sinus rhythm, patients with AF had an enlarged left atrium and lower ANP levels. The BNP/ANP ratio correlated significantly with left atrial diameter, LVDs and EF (r=0.429, P=0.0017; r=0.351, P=0.0117; and r=-0.349, P=0.0122; respectively), and was significantly higher among all the known operative indications for MR tested (LVDs 45 mm or more, EF 60% or less, NYHA class II or greater and AF; P=0.0073, P=0.003, P=0.0102 and P=0.0149, respectively). CONCLUSIONS: In chronic MR, levels of ANP and BNP, and the BNP/ANP ratio are potential indicators of disease severity.

The time-course changes of NT-proBNP and tissue Doppler indices in patients undergoing mitral valve replacement

“…Two other studies have examined patients with varying degrees of MR, and showed that changes in ventricular function occur early in the disease process, even before they could be detected echocardiographically 11,12. The diastolic filling ratios were higher in the study group, indicating LV decompensation and a rise in the filling pressures.…”

Natriuretic Peptides in Common Valvular Heart Disease

“…The most consistent, but not universal, association is with LA dimensions or volumes (85,89,90,92,93). AF was an independent predictor of BNP levels in one study (91), but another showed that both ANP and BNP decreased with very large atria in the presence of AF (94). BNP levels are higher in patients with functional compared with organic MR, but this reflects a greater degree of LV dysfunction with larger end-systolic volumes and greater wall stress (86).…”

“…Exceptions are a study including patients with organic MR in which there was a weak negative correlation between NT-proBNP and LVEF (r ϭ Ϫ0.25) (93) and a study in which the BNP/ANP ratio showed a similar finding (94). Similarly, there is no consistent association with right ventricular function, LV diastolic filling parameters, or measures of end-diastolic size (86,90,92,93).…”

“…Levels of BNP and NT-proBNP increase progressively with worsening symptomatic class, albeit with a considerable degree of overlap(86,87,90 -93). Shimamoto et al(94) found that plasma ANP was increased in patients with NYHA functional class II symptoms but then decreased in those with NYHA functional class III and IV symptoms, whereas BNP and hence the BNP/ANP ratio increased progressively. For NYHA functional class II, III, or IV, a cutpoint for a BNP/ANP ratio of 1.2 gave 88% sensitivity, 83% specificity, and an AUC of 0.82.…”

C-type natriuretic peptide and natriuretic peptide receptor B signalling inhibits cardiac sympathetic neurotransmission and autonomic function

“…ANP and BNP levels are greatly elevated in heart failure, 2 and are also negative prognostic indicators during hypertension, 3 and acute ischemic stroke 4 . They are both predominantly synthesized in the cardiac chambers, and released upon cardiac wall stretch into the circulation, modulating vascular tone, permeability, renal function, and the renin–angiotensin system 1 , 5 .…”