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Hemodynamic assessment of mitral stenosis: mitral valve resistance as an echocardiographic index.

BACKGROUND AND AIM OF THE STUDY
Although mitral valve (MV) resistance has been proposed as a new index for the determination of hemodynamic consequence in patients with mitral stenosis (MS), the relationship between this resistance and signs of hemodynamic deterioration, such as the elevation of pulmonary artery pressure and plasma levels of brain natriuretic peptide (BNP), has not yet been investigated.


METHODS
The study population comprised 33 consecutive patients (nine males, 24 females; mean age 39 +/- 6 years) with moderate and severe MS (MV area (MVA) <1.5 cm2). The cause of MS in all patients was rheumatic valvular disease. A comprehensive echocardiographic evaluation was performed, with MVA, mean MV pressure gradient (MVPG), systolic pulmonary artery pressure (sPAP) and mitral valve resistance being calculated for all patients, in addition to plasma BNP levels.


RESULTS
Both, plasma BNP level and sPAP correlated better with MV resistance (r = 0.75, p < 0.001 and r = 0.52, p = 0.002, respectively) than with MVA by pressure half-time method (MVA-PHT) (r = -0.68, p < 0.001 and r = -0.55, p = 0.001, respectively) and mean MVPG (r = 0.62, p < 0.001 and r = 0.69, p < 0.001, respectively). A comparison of MV resistance and conventional stenotic indices showed that MV resistance correlated best with mean MVPG (r = 0.70, p < 0.001), and correlated least with MVA-PHT (r = -0.45, p = 0.009). Patients with sPAP >50 mmHg and plasma BNP level >150 pg/ml had a significantly higher MV resistance than patients with sPAP < 50 mmHg and plasma BNP level <150 pg/ml.


CONCLUSION
MV resistance appeared to be better correlated with elevated sPAP and plasma BNP levels than with conventional stenosis indices.