Effect Of Balloon Mitral Valvuloplasty Research Articles

Effects of balloon mitral valvuloplasty on left atrial function in mitral stenosis as assessed by pressure–area relation

Objectives. This study sought to investigate the changes induced on the pressure–area relation of the left atrium in patients with mitral stenosis after percutaneous balloon mitral valvuloplasty.Background. Left atrial (LA) function is influenced by changes in LA afterload. The latter is increased in mitral stenosis as a result of increased resistance to blood flow imposed by the stenotic mitral valve.Methods. We studied the effects of acute alterations of LA afterload induced by retrograde nontransseptal balloon mitral valvuloplasty (RNBMV) on LA function in patients with mitral stenosis. LA pressure–area relations were obtained in 15 patients with mitral stenosis (8 with sinus rhythm, 7 with atrial fibrillation) before and after valvuloplasty, as well as in 15 normal subjects. LA pressure was recorded by a catheter-tipped micromanometer introduced retrogradely into the left atrium while LA area was recorded simultaneously using acoustic quantification. The areas of the A and V loops of the pressure–area relation as well as the LA chamber stiffness constant were calculated.Results. Balloon valvuloplasty resulted in a significant increase in mitral valve area (p < 0.001) and a substantial reduction of the mean transmitral pressure gradient (p < 0.001) and mean LA pressure (p < 0.001). The area of the A loop in patients with sinus rhythm and the area of the V loop in those with atrial fibrillation increased significantly after completion of the procedure (p < 0.001). Furthermore, LA stiffness decreased in both groups.Conclusions. After RNBMV, there is a significant increase in LA pump function in patients with sinus rhythm, a significant increase in LA reservoir function in patients with atrial fibrillation and a significant reduction in LA stiffness in all patients. Marked alterations of the configuration of the LA pressure–area relation occur immediately after successful RNBMV in patients with mitral stenosis.

Exercise capacity and skeletal muscle structure and function before and after balloon mitral valvuloplasty

This study evaluated the effects of balloon mitral valvuloplasty (BMV) on exercise capacity and skeletal muscle structure and function in 10 subjects with mitral stenosis (mean age ± SD 33 ± 5.5). Measurements were obtained before, and 2 weeks and 4 months after BMV to provide baseline data, to examine the effects of improved hemodynamics, and to examine the effects of resumption of normal physical activity, respectively. Valvuloplasty caused an increase in mitral valve area (0.89 ± 0.04 to 1.75 ± 0.07 cm 2; mean ± SE), and an increase in resting cardiac output (3.8 ± 0.18 to 4.6 ± 0.19 L/min, p < 0.05). At early follow-up after 2 weeks, subjects did more work (31% increase, p < 0.01) and had greater maximal oxygen consumption (11% increase, p < 0.01). However, measurements reflecting skeletal muscle histology, biochemistry, and function were unaltered at this stage. Four months after BMV, subjects had a further increase in exercise capacity compared with both baseline (58% increase, p < 0.01) and early follow-up (20% increase, p < 0.05). There were associated late increases compared with baseline in quadriceps cross-sectional area (66 ± 5.8 vs 61 ± 5.5 cm 2, p < 0.05) and torque production (125 ± 14 vs 118 ± 16 Nm, p < 0.05). The percentage of slow twitch type I fibers increased compared with baseline (41 ± 2.0% vs 33 ± 3.1%, p < 0.05), as did the size of type II fibers (5.9 ± 0.49 vs 4.9 ± 0.57 μm 2 × 10 3, p < 0.05). Citrate synthase activity at late follow-up was also greater than it was before BMV (193 ± 32.1 vs 131 ± 16.2 nmol/mg/min, p < 0.05), although cytochrome oxidase activity remained unaltered. Thus, skeletal muscle abnormalities are found in patients with mitral stenosis. An early increase in exercise capacity occurs after BMV without changes in skeletal muscle structure and biochemistry. However, longer term improvements in exercise performance are associated with alterations in skeletal muscle.

Plasma noradrenaline as an indicator of functional state in hearts with mitral stenosis: the influence of acutely reduced left atrial pressure by balloon mitral commissurotomy.

To investigate the mechanism in which plasma noradrenaline concentration (pNA) is elevated in heart failure, the effect of balloon mitral valvuloplasty was used as a model of acute manipulation of the left atrial pressure reduction in ten patients with mitral stenosis. Gorlin mitral valve area and pNA were correlated with New York Heart Association functional class and found to have a significant exponential inverse relationship with each other ([pNA, pg/ml] = 198.9 x [mitral valve area, cm2]-0.696; P = 0.003). Elevated pNA could be partially explained by a reduced cardiac index (CI) ([pNA, pg/ml] = 403.4 x [CI, l/min/m2]-0.889; P = 0.027; r = 0.495), especially in severely failed hearts, but not by pulmonary capillary wedge pressure (PCWP). However, the percent changes (% delta) of variables early after balloon valvuloplasty exhibited a paradoxical contrast; % delta pNA showing a clear negative exponential correlation with % delta PCWP ([% delta pNA] = 436.0 x [% delta PCWP + 80]-0.679 - 80; P = 0.021), but not with % delta CI. These results suggest that pNA should be considered an indicator of cardiac functional class in mitral stenosis. PNA is modulated by both cardiac index and pulmonary capillary pressure, but in different ways.

Effect of balloon mitral valvuloplasty on exercise capacity, ventilation and skeletal muscle oxygenation

Objectives. The short- and long-term effects of valvuloplasty on exercise capacity, ventilation and skeletal muscle oxygenation were investigated to determine whether a dissociation between hemodynamic improvement and exercise capacity occurs in patients with mitral stenosis.Background. Percutaneous balloon mitral valvuloplasty in patients with mitral stenosis results in immediate hemodynamic improvement at rest and with exercise. Improved exercise capacity has been described at 3 months after valvuloplasty. In patients with left ventricular dysfunction, acute therapeutic interventions that produce hemodynamic benefit do not immediately improve exercise capacity.Methods. Maximal bicycle exercise with measurement of respiratory gases was performed in 11 patients with mitral stenosis before and at 48 h and 3 months after successful percutaneous balloon mitral valvuloplasty. Respiratory and leg skeletal muscle oxygenation were assessed by monitoring changes in light absorption of the serratus anterior and vastus lateralis muscles using near-infrared spectroscopy and were expressed as percent deoxygenation.Results. Mitral valvuloplasty significantly increased mean mitral valve area from 1.0 ± 0.2 to 1.7 ± 0.3 cm2(p < 0.05). Immediately after valvuloplasty, peak exercise oxygen consumption (o2), o2at the anaerobic threshold, ventilation, peak respiratory and leg muscle deoxygenation all remained unchanged. At submaximal work loads, respiratory muscle deoxygenation was attenuated (25 W: before 12 ± 4%; 48 h 4 ± 3%; 50 W: before 10 ± 5%; 48 h 5 ± 4%; both p < 0.05).At 3 months, significant improvement in peak o2(before 10.9 ± 5%; 3 months 14.6 ± 6.2 ml/kg per min; p < 0.05) and o2at the anaerobic threshold (before 7.1 ± 2.4; 3 months 8.4 ± 2.3; p < 0.05) were observed, whereas ventilation remained unchanged. No further improvement was seen in respiratory muscle deoxygenation. Vastus lateralis deoxygenation at submaximal work loads tended to be decreased.Conclusions. Long-term changes in skeletal muscle and the lungs preclude immediate enhancement of exercise performance after balloon mitral valvuloplasty. Immediate symptomatic improvement probably results from an immediate decrease in the work of breathing. Long-term symptomatic improvement results from changes that occur in the peripheral skeletal musculature as well as from the reduced work of breathing.

The acute effects of balloon mitral valvuloplasty on the results of cardiopulmonary exercise testing

The acute effects of balloon mitral valvuloplasty on the results of cardiopulmonary exercise testing