Effects of percutaneous balloon mitral valvuloplasty on plasma B-type natriuretic peptide in rheumatic mitral stenosis with and without atrial fibrillation.

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the effect of percutaneous balloon mitral valvuloplasty (PBMV) on plasma B-type natriuretic peptide (BNP) levels in patients in sinus rhythm (SR) and with atrial fibrillation (AF).

METHODS: Thirty patients with rheumatic mitral stenosis who underwent successful PBMV were included in the study. Of these patents, 21 were in SR (SR group) and nine had AF (AF group). Plasma BNP levels were measured using the Triage BNP Test in all patients before, and at 20 min and 24 h after, PBMV. Control levels were measured in eight healthy volunteers.

RESULTS: Basal plasma BNP levels in patients were significantly higher than those in controls (123.5 +/- 69.5 versus 16.4 +/- 7.6 pg/ml, p < 0.01), and correlated with mean left atrial pressure (mLAP; r = 0.441, p < 0.05) and pulmonary artery pressure (PAP; r = 0.488, p < 0.01). No significant difference was observed in BNP levels between the SR and AF groups. In the SR group, BNP levels decreased after PBMV (pre-PBMV 128.7 +/- 75.9 pg/ml; at 20 min, 88.6 +/- 62.0 pg/ml; at 24 h, 43.4 +/- 26.7 pg/ml; respectively, p < 0.05). Changes in plasma BNP (deltaBNP) correlated positively with those in mLAP (deltamLAP) (r = 0.696, p < 0.01) and PAP (deltaPAP) (r = 0.456, p < 0.05). Left ventricular end-diastolic volume (LVEDV) (96.1 +/- 21.6 versus 111.5 +/- 25.2 ml, p < 0.01) and stroke volume (SV) (59.2 +/- 15.8 versus 69.0 +/- 17.9 ml, p < 0.05) augmented accordingly without any changes in left ventricular end-diastolic pressure (LVEDP) (p = NS). In contrast, in group AF, BNP levels remained unchanged (pre-PBMV 111.6 +/- 53.4 pg/ml; at 20 min, 122.0 +/- 68.7 pg/ml; at 24 h, 106.1 +/- 56.2 pg/ml; respectively, p = NS), while LVEDP increased (6.4 +/- 3.6 versus 8.6 +/- 3.2 mmHg, p < 0.01), without any changes in LVEDV and SV (p = NS).

CONCLUSION: The study results indicate that, in mitral stenosis patients, a high BNP level is associated with high mLAP and PAP. Cardiac rhythm may play an important role in changes of BNP level after PBMV. BNP may be a valid marker to reflect changes in mLAP and PAP after PBMV in patients with SR, but not in those with AF.