| Abstract: |
SUMMARYIntervention is recommended in symptomatic patients (New York Heart Association [NYHA] class II, III, and IV) with mitral stenosis and a mitral valve area of ≤1.5 cm Intervention is also indicated in patients with a similar valve area and pulmonary hypertension (pulmonary artery systolic pressure of 50 mm Hg at rest, 60 mm Hg with exercise). The presence of a thrombus that does not lyse with several months of anticoagulation in an otherwise-favorable valve, the presence of heavy calcification, marked subvalvular obstruction, and/or 3 to 4+ mitral). Regurgitation is an indication for valve replacement. Because the mortality and late morbidity are higher in valve replacement than in valve repair, the patient should be symptomatic despite medical management, at least NYHA class III, before valve replacement is recommended (ACC/AHA guidelines for the management of patients with valvular heart disease 2006).The estimated valve area can vary from rest to exercise, and explains the presence of a variety of patients with similar resting mitral valve areas, but different symptoms on exertion (Dahan et al., 1993 and Voelker et al., 1993).Therefore, stress echocardiography can help in the assessment of this population by correlating the change in mitral valve parameters with stress-induced hemodynamic variations (Bach et al., 1997 and Cheriex et al., 1994).In this work we aimed to study the effect of changes in blood flow across the mitral valve on mitral valve area measured by planimetry and PHT methods in patients with mitral stenosis.This study was carried out in Zagazige University hospital from June 2003 to September 2006 the studied patients included 10 males and 20 females (age range 17 to 52 years; mean 32.57±10.76 years); for all patients we did stress echocardiography using dobutamine to increase cardiac out put; mitral valve area assessment using both methods during rest and during dobutamine infusion.We divided our patients into two groups according to degree of the increase in cardiac out put with dobutamine infusion:Group I: Those with an increase of ≥ 50% in CO from base line.Group II: Those with an increase of < 50% in CO from base line.As regards the percent of changes in MVA by PHT there was significant difference between both groups (P<0.05). Also there was weakly significant difference between both groups as regard changes in MVA by planimetry (P= 0.074).There was highly significant difference between rest and peak dobutamine as regard increase in MVA by both methods and increase in peak and mean trans-mitral gradient in group 1 (P<0.01).There was highly significant difference between rest and peak dobutamine as regard increase in MVA by planimetry and increase in peak trans-mitral gradient in group II (P<0.0018). But there was weakly significant difference between rest and peak dobutamine as regard increase in MVA by PHT (P<0.0369). And non- significant difference between rest and peak dobutamine as regard increase in mean trans-mitral gradient. (P<0.05).There were non significant difference between the 2 groups as regards; Peak transmitral pressure gradient at rest, Peak transmitral pressure gradient at peak dobutamine dose, Mean transmitral pressure gradient at rest , Mean transmitral pressure gradient at peak dobutamine dose, transmitral TVI at rest, transmitral TVI at peak dobutamine dose& Changes in transmitral TVI; (P>0.05). But there was weakly significant difference between both groups as regard changes in peak transmitral pressure gradient; (P = 0.072). And there was highly significant difference between both groups as regard changes in mean transmitral pressure gradient; (P < 0.01).There was non significant correlation between change in COP and change in MVA by planimetry (r = 0.195, P = 0.15); change in COP and change in MVA by PHT (r = 0.259, P = 0.083); and baseline MVA and change in MVA by planimetry (r=0,007& P =0.485).But there was a highly significant negative correlation between baseline MVA and change in MVA by PHT (r = - 0.546, P = 0.009) between MVS and change in MVA by planimetry (r = - 0.448, P = 0.0063); and between MV score and change in MVA by PHT (r = - 0.492, P=0.002).In our work cardiac out put increased in both groups in spit of non- significant change in HR, and this observation means that stroke volume increased mainly by actual increase in mitral valve area which may be small but clinically significant.CONCLUSIONWe concluded that mitral valve area is dynamic and respond to changes in cardiac out put. Also we concluded that Doppler stress echocardiography is a feasible stress-testing technique with a low rate of complications.
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