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

Abstract

BackgroundIn severe mitral regurgitation, a subset of patients who are asymptomatic may develop left ventricular decompensation before changes in echocardiographic parameters become evident. Since N-terminal brain natriuretic peptide (NT-proBNP) is used to detect early heart failure, we hypothesised that NT-proBNP would be activated in patients with mitral regurgitation.MethodsPatients submitted to surgery were prospectively evaluated over eight months in the Department of Cardiology at Inkosi Albert Luthuli Central Hospital. Control patients with severe mitral regurgitation were obtained from the outpatient clinic. In order to define their value in identifying left ventricular decompensation, NT-proBNP levels and tissue Doppler imaging (TDI) indices were simultaneously measured and compared with conventional echocardiographic indices at baseline and this was repeated at one week and at six weeks after valve replacement.ResultsMean NT-proBNP levels were markedly elevated pre-operatively in all surgical cases compared to controls (p = 0.0001). The diastolic E-mitral/E-annulus ratio, measured using TDI, was higher in the study group, indicating higher left ventricular filling pressure present in the study group. NT-proBNP levels increased further at one week after surgery and subsided at the six-week follow-up visit to levels similar to the control group. The TDI diastolic ratio also decreased at one week, and increased slightly again at the six-week follow up. These changes were accompanied by significant reduction in left atrium and left ventricular chamber dimensions with an increase in the ejection fraction from one to six weeks.ConclusionMarked differences in mean NT-proBNP levels and TDI ratios between the study and control groups suggest that using TDI and NT-proBNP assays may detect covert left ventricular decompensation.

Effect of mitral valve replacement on left ventricularfunction in subjects with severe rheumatic mitralregurgitation

“…[7] Under these circumstances mitral valve replacement is associated with higher morbidity and mortality due to advanced LV impairment. [9] None of our seven patients in the group with the EF 40-49% (median EF 42%) underwent mitral valve repair which is recommended under these circumstances. The choice of the surgical procedure was dependent on the available expertise at our centre to carry out MV repair which is technically difficult in RHD compared to non-rheumatic MR.…”

“…shown that patients with severe mitral regurgitation frequently presented late; many were in heart failure, beyond the optimal period for surgical intervention as judged by the echocardiographic parameters and confirmed on natriuretic peptide estimation. [9] However, this study did not describe the outcome of subjects undergoing surgery for rheumatic MR who have impaired LV function, since few patients had overt impairment of LV function [9].…”

“…[8] The mechanism of mitral regurgitation in rheumatic carditis involves annular dilatation, chordal elongation and anterior mitral leaflet prolapse. [9,10] As the lesions of MR progress, left ventricular volume overload ensues as a result of an increased regurgitant orifice area. [11] The volume loaded left ventricle increases LV diastolic wall stress which leads to the development of further LV chamber enlargement.…”

Left atrial deformation: Useful index for early detection of cardiac damage in chronic mitral regurgitation

“…Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels increased among all moderate or severe chronic MR. It has already shown that in MR, changes in volume load may be paralleled by changes in the N-terminal brain natriuretic peptide (NT-proBNP) level and that the fall in NT-proBNP was related to corrections in volume and removal of the diastolic run-off into the left atrium [45] , [46] . However there are no data on the relationship between levels of ANP, BNP, NT-proBNP and atrial strain in patients with mitral regurgitation.…”