Improvement in exercise capacity and exercise hemodynamics 3 months after double-balloon, catheter balloon valvuloplasty treatment of patients with symptomatic mitral stenosis

Segmental and global longitudinal strain measurement by 2-dimensional speckle tracking echocardiography in severe rheumatic mitral stenosis

BACKGROUND

The present study aimed to detect subtle left ventricular (LV) dysfunction in patients with severe rheumatic mitral stenosis (MS) by measuring global and segmental longitudinal strain with a two-dimensional speckle tracking echocardiography (2D-STE) method.

METHODS

In this case-control study, 65 patients with severe rheumatic MS and preserved ejection fraction (EF ≥ 50% measured by conventional echocardiographic methods) were compared with 31 otherwise healthy control subjects. All patients underwent LV strain measurement by the 2D-STE method in addition to conventional echocardiography using a VIVID S60 echocardiography device.

RESULTS

Absolute strain values in myocardial segments 1-8, 10, and 12 (all basal, mid anterior, mid anteroseptal, mid inferior, and mid anterolateral segments) were significantly lower in patients with severe MS compared with the control group (P < 0.05 for all). The absolute global longitudinal strain (GLS) value was higher in the control group (-19.56 vs. -18.25; P = 0.006). After adjustment for age, gender, and systolic blood pressure, the difference in GLS between the two groups was as follows: mean difference=-1.16; 95% CI: -2.58-0.25; P = 0.110.

CONCLUSION

In patients with severe rheumatic MS and preserved EF, the absolute GLS tended to be lower than healthy controls. Furthermore, the segmental strain values of LV were significantly lower in most of the basal and some mid-myocardial segments. Further studies are warranted to investigate the underlying pathophysiology and clinical implications of this subclinical dysfunction in certain segments of patients with severe rheumatic MS.

Cardiovascular magnetic resonance characterization of rheumatic mitral stenosis: findings from three worldwide endemic zones

BACKGROUND

Cardiac remodeling in rheumatic mitral stenosis (MS) is complex and incompletely understood. The objective of this study was to evaluate cardiac structural and functional changes in a cohort of patients with rheumatic MS using cardiovascular magnetic resonance (CMR).

METHODS

This retrospective study included 40 patients with rheumatic MS, consisting of 19 patients from India, 15 patients from China, and 6 patients from Mexico (median (interquartile range (IQR)) age: 45 years (34-55); 75% women). Twenty patients were included in the control group. CMR variables pertaining to morphology and function were collected. Late gadolinium enhancement (LGE) sequences were acquired for tissue characterization. Statistical analyses were performed using the Kruskal-Wallis test and the chi-square test.

RESULTS

Compared to the control group, patients with MS had lower left ventricular (LV) ejection fraction (51% (42%-55%) vs 60% (57%-65%), p < 0.001), lower right ventricular (RV) ejection fraction (44% (40%-52%) vs 64% (59%-67%), p < 0.001), higher RV end-diastolic volume (72 (58-87) mL/m2 vs 59 (49-69) mL/m2, p = 0.003), larger left atrial volume (87 (67-108) mL/m2 vs 29 (22-34) mL/m2, p < 0.001), and right atrial areas (20 (16-23) cm2 vs 13 (12-16) cm2, p < 0.001). LGE was prevalent in patients with rheumatic MS (82%), and was commonly located at the RV insertion sites. Furthermore, the patient cohorts from India, China, and Mexico were heterogeneous in terms of baseline characteristics and cardiac remodeling.

CONCLUSION

Our findings demonstrated that biventricular dysfunction, right and left atrial remodeling, and LGE at the RV insertion sites are underappreciated in contemporary rheumatic MS. Further studies are needed to elucidate the prognostic implications of these findings.

Mechanism of improvement in exercise capacity after the maze procedure combined with mitral valve surgery

OBJECTIVE

To clarify the mechanism of improvement in exercise capacity after the maze procedure.

DESIGN

Retrospective study.

SETTING

Tertiary referral centre.

PATIENTS

26 patients (mean (SD) age 57 (9) years) with atrial fibrillation (AF) and mitral valve disease were studied with echocardiography and cardiopulmonary exercise testing before and after the maze procedure combined with mitral valve surgery. Of these, eight had persistent AF and 18 had restored sinus rhythm (SR) by the surgery. Six patients (mean (SD) age 59 (12) years) with AF undergoing mitral valve surgery without the maze procedure who had cardiopulmonary exercise testing before and after the surgery formed the control group.

MAIN OUTCOME MEASURES

Echocardiographic parameters of atrial function were measured from transmitral flow recordings. Peak oxygen uptake (VO2) and the slope of the relation between VO2 and workload (ratio of DeltaVO2 to Delta work) were determined as indices of exercise capacity.

RESULTS

The degree of improvements in peak VO2 and the ratio of DeltaVO2 to Delta work after the mitral valve surgery was comparable between the maze and control group. It was also comparable between patients with and those without successfully restored SR after the maze procedure. The degree of the increase in peak VO2 correlated with the change in left atrial diameter (r = -0.40, p = 0.047) but atrial contraction did not correlate with the increase.

CONCLUSIONS

Improvement in exercise capacity may not be caused by restored SR and atrial contraction but may at least partly relate to the reduction of left atrial size and improvement of haemodynamic variables by the surgery.

Does balloon mitral valvuloplasty improve cardiac function? A mechanistic investigation into impact on exercise capacity

Procedural technical success of balloon mitral valvuloplasty (BMV) is indicated by an increase in valve area and a reduction in transvalvar gradient, but there are conflicting results regarding whether these indicators correlate with subsequent improvements in exercise capacity. We conducted a study to explore the effects of valvuloplasty on cardiac function to gain insight into the mechanisms responsible for the impact on exercise ability. Sixteen patients with mitral stenosis participated in the study and the five who did not proceed to valvuloplasty served as the control group. All patients performed maximal cardiopulmonary exercise tests before and 6 weeks after valvuloplasty (without valvuloplasty in controls). Central haemodynamics including cardiac output were measured non-invasively at rest and peak exercise. At baseline, the cardiopulmonary exercise test results were similar in the two groups. Following valvuloplasty, cardiac output did not alter at rest, but increased significantly at peak exercise (8.7+/-1.7 to 10.5+/-2.1 l min(-1), P<0.01), as did peak cardiac power output (1.88+/-0.55 to 2.28+/-0.74, P<0.05) and cardiac reserve (1.07+/-0.33 to 1.45+/-0.55 watts, P<0.05). Aerobic exercise capacity improved (13.9+/-4.2 to 16.4+/-4.3 ml kg(-1) min(-1), P<0.01) as did exercise duration (354+/-270 to 500+/-266 s, P<0.01). There were no significant changes in the controls. There was a significant correlation between the changes in peak VO(2) and changes in cardiac reserve (r=0.62, P<0.01) but not with changes in resting haemodynamics. These changes did not correlate with changes in peri-procedural mitral valve haemodynamics, despite increases in mitral valve area from 1.05+/-0.16 to 1.74+/-0.4 cm(2) (P<0.0001), accompanied by falls in the transvalvar gradient and pulmonary artery pressure (12.4+/-4.7 to 4.5+/-3 mmHg, and 26.8+/-8.4 to 17.4+/-5.2 mmHg, respectively, all P<0.0001). In conclusion, we found that successful mitral valvuloplasty in our patient cohort led to improved cardiac and physical functional capacity but not resting haemodynamics. Neither indicators of technical success nor resting haemodynamics were very reliable in predicting functional improvement.

Determinants of delayed improvement in exercise capacity after percutaneous transvenous mitral commissurotomy

BACKGROUND

Percutaneous transvenous mitral commissurotomy (PTMC) results in short-term hemodynamic and symptomatic improvements. We have previously shown that the immediate symptomatic relief is related to the improvement in excessive exercise ventilation. The exercise capacity, however, does not improve in the short term but does improve gradually over several months. The pathophysiologic basis for the delayed improvement in exercise capacity has not been fully evaluated.

METHODS

To elucidate the determinants of improvement in exercise capacity late after PTMC, maximal ergometer exercise with respiratory gas analysis and exercise hemodynamic measurements were performed in 22 patients with symptomatic mitral stenosis before, immediately after, and 7 months after PTMC.

RESULTS

Mitral valve area increased from 0.9 +/- 0.2 cm(2) to 1.7 +/- 0.4 cm(2) after PTMC (P <.01). Significant improvements were observed in symptoms, cardiac output at peak exercise (6.6 +/- 1.5 L/min vs 8.6 +/- 1.9 L/min, P <.01), and mean pulmonary artery pressure at peak exercise (54.1 +/- 15.6 mm Hg vs 42.3 +/- 9.5 mm Hg, P <.01) immediately after PTMC. Excessive exercise ventilation, as assessed by the slope of the regression line between expired minute ventilation and carbon dioxide output (VE-VCo(2)), decreased significantly from 38.2 +/- 8.2 to 33.3 +/- 4.9 (P <.01). There were no significant changes in peak oxygen uptake (from 17.5 +/- 3.2 mL/kg per minute to 17.9 +/- 3.6 mL/kg per minute) immediately after PTMC. At 7 months, improved mitral valve area, symptoms, cardiac output at peak exercise, mean pulmonary artery pressure at peak exercise, and VE-VCo(2) were unchanged compared with values immediate after PTMC. Significant improvement was observed in peak oxygen uptake (19.7 +/- 3.0 mL/kg per minute [P <.01 compared with pre-PTMC or immediate post-PTMC values]). The increase in exercise cardiac output or the decrease in pulmonary artery pressure was not correlated with the late improvement in peak oxygen uptake. The short- or long-term improvements in VE-VCo(2), however, were significantly correlated with the late improvement in peak oxygen uptake.

CONCLUSIONS

Our results suggest that ventilatory improvement, not increased exercise cardiac output, contributed at least in part to the late improvement in exercise capacity after PTMC.

Percutaneous mitral valve dilatation with the Multi-Track System

We developed the Multi-Track System for percutaneous mitral valvotomy and described the preliminary results in 1995. Here we report the first 100 consecutive cases after the original publication. Two separate balloon catheters are positioned on a single guidewire. The first catheter, with only a distal guidewire lumen, is introduced into the vein and then advanced into the mitral orifice. Subsequently, a rapid exchange balloon catheter running on the same guidewire is inserted and lined up with the first catheter so the two are positioned side by side. Both balloons are then inflated simultaneously. Age of the patients was 31 +/- 12.8 years and weight 50 +/- 14 kg. Valve area increased 0.75 +/- 0.22 cm(2) to 2.00 +/- 0.32 cm(2)and mean left atrial pressure dropped from 27 +/- 8 to 11 +/- 5 mm Hg. One patient had significant mitral insufficiency after dilatation, which did not require surgery. The Multi-Track System is a valid alternative to the existing procedures for the treatment of mitral stenosis and uses simpler and less costly catheters. Cathet. Cardiovasc. Intervent. 48:178-183, 1999.

Five-year follow-up after percutaneous balloon mitral valvuloplasty in children and adolescents

Balloon mitral valvuloplasty (BMV) is an effective intervention in patients with symptomatic mitral stenosis. However, the late results of BMV in children and adolescents have not been well studied. The aim of this study was to assess the late functional and morphologic results after BMV in children and adolescents. BMV was performed in 46 children and adolescents (mean age 15.5 +/- 3.2 years, range 7 to 19; 19 males) with rheumatic mitral stenosis. Serial clinical and echocardiographic evaluation was conducted to assess the long-term results of the procedure during a follow-up period of 66 +/- 6 months. The mitral valve score was 6 +/- 2/16. BMV was successful in 45 patients (98%). There was a significant increase of the mean mitral valve area index (MVAI) (0.65 +/- 0.14 vs 1.54 +/- 0.23 cm2/m2, p <0.001) and a significant reduction of the mean transmitral pressure gradient (16.1 +/- 2.9 vs 5.1 +/- 3.1 mm Hg, p <0.001) from pre- to post-BMV, respectively. There was no significant change of MVAI or the pressure gradient during the follow-up compared with immediately after BMV (1.51 +/- 0.31 cm2/m2 and 4.9 +/- 2.5 mm Hg, respectively). No deaths or mitral valve replacement occurred during the follow-up period. Restenosis (loss of >50% of the achieved increase in MVAI) occurred in 3 patients (6.5%). All other patients showed persistent improvement in their New York Heart Association class (< or = II). Thus, the event-free survival with good functional results was encountered in 42 patients (91%) at the end of the follow-up period. The left atrial diameter decreased from 4.6 +/- 0.9 before BMV to 3.7 +/- 0.6 cm at follow-up (p <0.05). It is concluded that BMV has excellent intermediate-term results in children and adolescents with a relatively low mitral valve score.

Immediate and long-term results of percutaneous Inoue balloon mitral commissurotomy with use of a simple height-derived balloon sizing method for the stepwise dilation technique

OBJECTIVE

To assess the short- and long-term efficacy of Inoue balloon percutaneous transvenous mitral commissurotomy (PTMC) with use of our simple balloon sizing method based on patient height.

DESIGN

Data from 105 consecutive patients with symptomatic mitral stenosis who underwent 107 PTMC procedures between October 1991 and April 1995 at our hospital were analyzed.

RESULTS

All PTMC procedures were successfully completed with no instances of cardiac perforation, systemic embolism, severe mitral regurgitation (grade 3 or more angiographically), or death. The mean mitral valve area increased from 0.8 +/- 0.2 cm2 to 1.7 +/- 0.4 cm2 (P = 0.0001), as assessed echocardiographically. Optimal results -- defined as an improvement in valve area of 50% or more or a final valve area of 1.5 cm2 or more without significant mitral regurgitation (an increase in mitral regurgitation of two or more grades or a final regurgitation of grade 3 or more) -- were obtained in 96% of patients. At a mean follow-up interval of 20 months, symptomatic benefit was maintained in 97% of patients. Echocardiographic evidence of restenosis (loss of more than 50% initial gain in valve area, a valve area of less than 1.5 cm2, or both) was noted in 9.8%.

CONCLUSION

Inoue balloon PTMC with use of our simple balloon sizing method yielded excellent short- and long-term results in terms of mitral valve enlargement and sustained symptomatic benefit without the creation of severe mitral regurgitation.

Delayed improvement in skeletal muscle metabolism and exercise capacity in patients with mitral stenosis following immediate hemodynamic amelioration by percutaneous transvenous mitral commissurotomy

The abrupt improvement in hemodynamics after successful percutaneous transvenous mitral commissurotomy (PTMC) does not immediately enhance exercise capacity. Improved exercise capacity several months after PTMC has been reported. We hypothesized that the delayed improvement in exercise capacity is due partly to the slow improvement in the metabolism of skeletal muscle. This study examined the short- and long-term effects of PTMC on exercise capacity and skeletal muscle metabolism in patients with mitral stenosis. Treadmill exercise testing with respiratory gas analysis was performed in 11 patients with symptomatic mitral stenosis before and 3, 30, and 90 days after successful PTMC. On the same schedule, forearm metabolism of high-energy phosphates was measured by magnetic resonance spectroscopy during and after handgrip exercise. Ten healthy volunteers were examined. PTMC resulted in an immediate symptomatic improvement. However, exercise capacity and skeletal muscle metabolism remained unchanged 3 days after PTMC. At 30 days after PTMC, there were significant improvements in peak oxygen consumption (p <0.05), intracellular pH at end-exercise (p <0.05), and time constant for phosphocreatine recovery (mean +/- SD 88.9 +/- 11.3 vs 106.3 +/- 11.7 seconds, p <0.01) compared with these baseline values. These improvements remained even at 90 days after PTMC. Exercise capacity improved with some time delay after immediate hemodynamic amelioration by PTMC. Long-term improvement in exercise capacity depends partly on the slowly progressing improvement in skeletal muscle metabolism after long-standing mitral stenosis.

Acute alterations of oxygen uptake and symptom-limited exercise time in patients with mitral stenosis after balloon valvuloplasty

STUDY OBJECTIVES

To determine the acute influence of improvement in orifice area in mitral stenosis by percutaneous transluminal valvuloplasty (PTVP) on cardiopulmonary exercise capacity, treadmill walking time (TWT), oxygen uptake parameters at maximum exercise as well as at highest comparable workloads and parameters of breathing work were assessed pre- and post-PTVP.

PATIENTS AND INTERVENTIONS

PTVP was carried out in 16 patients who had moderately severe mitral stenosis, bringing about an average increase in mitral valve orifice area from 1.0 +/- 0.1 cm2 to 2.2 +/- 0.5 cm2 (p < 0.0005). Based on standardized conditions, the patients (six in functional class A, five in class B, and five in class C according to Weber's classification) underwent symptom-limited treadmill cardiopulmonary exercise testing before as well as 2 days after PTVP. In addition, subgroup analysis (eight patients in sinus rhythm, eight patients in atrial fibrillation) was performed to determine a potential influence of the underlying cardiac rhythm on cardiopulmonary exercise parameters. To rule out a PTVP-independent training effect, a control group of ten patients with mitral stenosis underwent the same kind of cardiopulmonary exercise testing on 2 consecutive days.

MEASUREMENTS AND RESULTS

After-PTVP, TWT augmented by 19% (p < 0.0005) in all patients. Maximum oxygen uptake in percent of predicted maximal values at peak exercise and at anaerobic threshold was enhanced by 10% (p < 0.005). Ventilation at highest comparable workload was diminished by 10% (p < 0.025), whereas oxygen uptake and oxygen pulse at highest comparable workload did not differ, reflecting both unaltered cardiac output at comparable workloads and a more economic ventilation, respectively. Furthermore, PTVP-mediated alterations of TWT, but not of oxygen uptake at peak exercise were more pronounced in patients in sinus rhythm than in those in atrial fibrillation, reflecting more effective economization of cardiac work and ventilation in the former subgroup. Except for a statistically significant increase of TWT of 5%, no clinically relevant differences between both exercise tests were found with respect to oxygen uptake in the control group.

CONCLUSIONS

Impaired cardiopulmonary fitness in patients with moderately severe mitral stenosis is improved substantially by PTVP immediately after the intervention, mainly the result of acute reduction of pulmonary congestion and subsequent decrease in dead space to tidal volume ratio. Adherence to standardized conditions is considered crucial for comparability of cardiopulmonary data.

Controversies in balloon mitral valvuloplasty: the when (timing for intervention), what (choice of valve), and how (selection of technique)

Despite the established role of percutaneous balloon mitral valvuloplasty (BMV) in the treatment of mitral stenosis, major controversial issues in the realm of BMV persist. With increased operator experience, BMV has now been extended to include various controversial scenarios, such as mild mitral stenosis, adverse valve morphologies, and high-risk patients with concomitant anatomic distortions which are technically demanding. In skilled hands, however, BMV has yielded a favorable outcome in these settings. Furthermore, the debate on whether the Inoue or the double-balloon approach is superior continues. Studies to date have shown equal efficacy of the two BMV methods in terms of valve enlargement although the Inoue approach is clearly simpler to execute and may potentially be associated with a lower risk of creating severe mitral regurgitation. Last, because of the lack of consensus on optimal balloon sizing for BMV, perhaps the best method to adopt at this stage is one that is simple and safe to apply across a broad spectrum of valve anatomy.

A simple balloon-sizing method in Inoue-balloon percutaneous transvenous mitral commissurotomy

This study was carried out to examine whether the previously determined balloon sizing method based on patient height was valid for percutaneous transvenous mitral commissurotomy using the current second-generation Inoue balloon catheter. The study consisted of 70 patients with pliable noncalcified mitral valves (group 1) and 85 patients with calcified mitral valves and/or severe subvalvular lesions (group 2). The mitral valve area was increased more in group 1 than in group 2 (1.0 +/- 0.3 to 1.9 +/- 0.5 cm2 versus 1.0 +/- 0.3 to 1.6 +/- 0.5 cm2, P = 0.002). Using the stepwise dilatation technique, none of the group 1 patients developed severe mitral regurgitation. Severe mitral regurgitation occurred in 4 patients (4.7%) in group 2. In conclusion, a simple balloon sizing method based on body height for selection of an appropriate-sized balloon catheter, as well as an initial inflated balloon diameter for the stepwise dilatation technique is useful for optimal acute outcomes in mitral commissurotomy.

Assessment of cardiac volumes and left ventricular mass by cine computed tomography before and after mitral balloon commissurotomy

We used cine computed tomography (CT) to determine whether decreased mitral valve gradients and pulmonary artery pressures resulted in decreased right ventricular and atrial volumes after percutaneous mitral balloon commissurotomy (MBC). In patients treated for severe mitral stenosis, previous studies have shown that after the mitral valve gradient decreases, the left atrial volume is reduced and left ventricular stroke volume is increased. The effects of commissurotomy on right heart chamber sizes have been difficult to assess with angiography and echocardiography. Moreover, in follow-up studies performed after surgery, changes in cardiac chamber volumes occurring after the mitral valve gradient and pulmonary pressure are reduced are confounded by the effects of thoracotomy. Our group has previously demonstrated that cine CT can accurately measure both left and right cardiac chamber volumes. We studied 11 female patients before, immediately after, and at 1 year after MBC, and 9 female control subjects of comparable age. To assess cardiac chamber volumes, we used cine CT. To assess the effects of MBC, we used cardiac catheterization and Doppler echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Mitral balloon valvotomy in children with Inoue balloon technique: immediate and intermediate-term result

Percutaneous mitral balloon valvotomy (PMV) using the Inoue balloon technique was attempted in 170 patients. Of these, 30 patients were children aged 10 to 18 years (mean 15.9 +/- 2.7 years). There were 16 female and 14 male patients. All were in sinus rhythm. The procedure was successful in 28 patients (93%). PMV was performed using 20 to 28 mm (mean 25 mm) diameter balloon catheters with an echo-Doppler guided stepwise mitral dilation technique. After PMV, the mean left atrial pressure decreased from 25 +/- 5 to 14 +/- 4 mm Hg (p < 0.001). The mean mitral valve gradient (MVG) decreased from 16 +/- 4 to 6 +/- 3 mm Hg (p < 0.001). The mitral valve area (MVA) by catheter increased from 0.7 +/- 0.2 to 1.7 +/- 0.5 cm2 (p < 0.001), and MVA as determined by echocardiography (2DE) increased from 0.8 +/- 0.1 to 1.9 +/- 0.3 cm2 (p < 0.01). There were no deaths or thromboembolic complications; cardiac tamponade developed in one patient, mild mitral regurgitation (MR) developed in three patients (10%) and increased by one grade from (1+ to 2+) in another two patients (8%). A small atrial septal defect (ASD) assessed by color flow mapping developed in seven patients (25%); 90% were closed at 3 months. The Doppler and 2DE MVAs were maintained at 1.8 +/- 0.4 cm2 at 17 months' mean follow-up; one patient developed restenosis. We conclude the PMV using the Inoue balloon catheter is safe and effective in the treatment of severe mitral stenosis in children, with a low complication rate.

Contribution of mitral valve reserve capacity to sustained symptomatic improvement after balloon valvulotomy in mitral stenosis: implications for restenosis

OBJECTIVES

To explain the discrepancy between the symptomatic status of patients and the hemodynamically calculated mitral valve area during long-term follow-up after mitral balloon valvulotomy, mitral valve orifice variability after dobutamine infusion was investigated in two groups of patients.

BACKGROUND

A significant increase in aortic valve area with increased aortic transvalvular flow has been reported in patients with calcific aortic stenosis after aortic balloon valvulotomy. A similar phenomenon with regard to the mitral valve has not been studied in detail.

METHODS

Group 1 comprised 10 patients (mean age 33 +/- 9 years) with untreated mitral stenosis. Group 2 comprised 29 consecutive patients (mean age 32 +/- 7 years) who underwent successful percutaneous mitral balloon valvulotomy 13 +/- 2 months before the study.

RESULTS

After dobutamine infusion, heart rate and cardiac index increased significantly in both groups. The mean pulmonary artery pressure, mitral valve gradient and pulmonary capillary pressure remained unchanged in Group 2 but increased significantly in Group 1. The mean mitral valve area was significantly larger in Group 2 after dobutamine infusion than at baseline (1.9 +/- 0.5 vs. 2.4 +/- 0.6 cm2, p < 0.0001) but was unchanged in Group 1 (1.2 +/- 0.2 vs. 1.3 +/- 0.3 cm2, p = NS). The mean mitral valve area in seven patients in Group 2 (24%) was < or = 1.5 cm2 before dobutamine infusion (1.3 +/- 0.4 cm2), which was defined as restenosis. In five of these seven patients who had minimal or no symptoms, the mitral valve area increased significantly after dobutamine infusion (1.3 +/- 0.1 vs. 1.9 +/- 0.1 cm2). In the other two patients who were symptomatic, the mitral valve area did not change after dobutamine infusion. These two patients were identified as having "true" restenosis, and redilation of the mitral valve was performed in both.

CONCLUSIONS

In patients who underwent mitral balloon valvulotomy, increased mitral valve reserve capacity contributed to symptomatic improvement on long-term follow-up. Dobutamine infusion may be helpful in detecting clinically significant restenosis.

Effects of percutaneous transluminal mitral valvuloplasty on plasma catecholamine levels during exercise

Elevation of plasma catecholamine levels during exercise in patients with mitral stenosis correlated with the severity of the disease. We investigated the plasma norepinephrine changes in six patients before and after percutaneous transluminal mitral valvuloplasty (PTMV) during continuously graded ergometer exercise. Peak exercise intensity was increased from 65.8 W to 87.5 W after PTMV. Plasma norepinephrine level at 60 W workload intensity was decreased from 2308 +/- 864 pg/ml to 841 +/- 233 pg/ml after PTMV (p < 0.05). We concluded that PTMV decreased the plasma norepinephrine level during exercise in the patients with mitral stenosis. Percutaneous transluminal mitral valvuloplasty is a novel procedure for the improvement of symptoms in patients with mitral stenosis.

Effect of percutaneous balloon valvuloplasty on pulmonary hypertension in mitral stenosis

Percutaneous mitral balloon valvuloplasty (PMBV) has been useful in decreasing mitral valve obstruction in mitral stenosis; however, the long-term effects of valvuloplasty on pulmonary artery pressure have not been extensively studied. Thirty-three patients underwent PMBV in our institution between January 1988 and December 1991. There were significant reductions in peak (19 +/- 1 to 12 +/- 1 mm Hg) and mean (10 +/- 0.7 to 6 +/- 0.4 mm Hg) mitral valve gradients estimated by Doppler techniques immediately after PMBV. The mitral valve area, as assessed by the pressure half-time method, increased from 1.06 +/- 0.05 to 1.98 +/- 0.08 cm2 (p < 0.001) after the procedure and remained significantly greater (1.68 +/- 0.11 cm2) at 17 +/- 2 months. Right ventricular systolic pressure (RVSP) was estimated in patients with tricuspid regurgitation (TR) using the modified Bernoulli equation. There was a good correlation between Doppler and catheterization for RVSP (r = 0.83 pre valvuloplasty; r = 0.87 post valvuloplasty). Right ventricular systolic pressure by Doppler was 56 +/- 4 mm Hg before valvuloplasty and 48 +/- 4 mm Hg immediately afterwards (p < 0.001). Nine patients had TR on follow-up Doppler studies with an estimated RVSP of 53 +/- 9 mm Hg (p = NS compared with pre- and post-valvuloplasty values). Six of these nine patients had moderate or severe mitral regurgitation (MR), compared with one patient without TR at follow-up (p < 0.05). There appears to be a good correlation between the RVSP determined by Doppler and measured at catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular diastolic pressure-volume response immediately after successful percutaneous transvenous mitral commissurotomy

The left ventricular (LV) diastolic pressure-volume response after percutaneous transvenous mitral commissurotomy (PTMC) was investigated to determine whether it was related to the baseline conditions of the left ventricle. Left ventriculography was performed, and the measurements of LV pressure were obtained in 32 patients before and after PTMC. Mitral valve area increased from 1.0 +/- 0.3 to 1.9 +/- 0.4 cm2 (p < 0.005) after PTMC, which caused a decrease in left atrial mean pressure (14.8 +/- 5.9 to 7.4 +/- 2.7 mm Hg; p < 0.005). LV end-diastolic pressure increased in all patients 5 minutes after PTMC. However, patients could be divided into 2 groups according to the following changes in LV end-diastolic pressure 20 minutes after PTMC: In 22 patients, LV end-diastolic pressure returned to the near-baseline level 20 minutes after PTMC (before 5.0 +/- 2.2, 5 minutes after 8.6 +/- 3.1, and 20 minutes after 6.3 +/- 2.5 mm Hg) with a significant increase in LV end-diastolic volume index (64 +/- 12 to 74 +/- 14 ml/m2; p < 0.001) and augmentation of LV stroke volume index (39 +/- 9 to 47 +/- 11 ml/m2; p < 0.001). However, in the remaining 10 patients with a larger LV volume (> 80 ml/m2) and reduced ejection fraction (< 50%) at baseline, LV end-diastolic pressure further increased 20 minutes after PTMC (before 5.5 +/- 2.8, 5 minutes after 7.8 +/- 2.7, and 20 minutes after 11.0 +/- 2.9 mm Hg) without significant changes in LV volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary artery pressure and pulmonary vascular resistance before and after mitral balloon valvotomy in 100 patients with severe mitral valve stenosis

We studied the pulmonary vascular hemodynamics before and after mitral balloon valvotomy in 100 patients with severe mitral valve stenosis. Before balloon valvotomy 23 patients had a pulmonary artery systolic pressure of < 31 mm Hg (group 1), 54 patients had a pulmonary artery systolic pressure between 31 and 50 mm Hg (group 2), and 23 patients had a pulmonary artery systolic pressure of > 50 mm Hg (group 3). After balloon valvotomy the mean systolic pulmonary artery pressure in group 1 decreased from 28 +/- 3 to 26 +/- 5 mm Hg (p = NS). In group 2 the systolic pulmonary artery pressure after balloon valvotomy decreased from 41 +/- 5 to 33 +/- 7 mm Hg (p < 0.0001) and normalized to < 31mm Hg in 27 patients (50%). The mean left atrial pressure was abnormal (> or = 13 mm Hg) in 6 of 27 patients (22%) who had a systolic pulmonary artery systolic pressure of < 31 mm Hg and in 6 of 27 patients (22%) with a pulmonary artery systolic pressure of > or = 31 mm Hg. The pulmonary vascular resistance was abnormal in 36 of 54 patients (67%) after mitral balloon valvotomy; only 5 of 36 patients (14%) had a raised left atrial pressure (> or = 13 mm Hg). In group 3 the pulmonary vascular resistance was abnormal (> 125 dynes/sec/cm-5) in all 23 patients before and in 19 of 31 patients (91%) after balloon valvotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

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 (VO2), VO2 at 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 VO2 (before 10.9 +/- 5%; 3 months 14.6 +/- 6.2 ml/kg per min; p < 0.05) and VO2 at 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.

Hemostatic changes induced by percutaneous mitral valvuloplasty

A study was conducted of hemostatic changes in 15 patients with mild-to-moderate rheumatic mitral stenosis who underwent percutaneous mitral balloon valvuloplasty (PMV). The patients were divided into two groups according to the degree of valve dilatation as evaluated by Doppler echocardiography before and 2 to 3 months after therapy: one group (n = 7) with suboptimal valvuloplasty (< 0.5 cm2) and one (n = 8) with optimal valvuloplasty (> or = 0.5 cm2). On the day of echocardiographic evaluation, hemostatic testing of the platelet, coagulation, and fibrinolytic systems was performed. Before PMV there were no differences in the hemodynamic and hemostatic variables between the two groups. No favorable hemostatic changes were achieved by PMV in the suboptimal group. In the optimal group, however, platelet-specific protein levels decreased after PMV; the mean levels of platelet factor 4 and beta-thromboglobulin were moderately elevated before and decreased after PMV from 38.5 +/- 22.2 to 8.13 +/- 5.08 ng/ml (p < 0.01) and from 132.5 +/- 78.6 to 38.8 +/- 19.5 ng/ml (p < 0.02), respectively. Coagulation and fibrinolytic systems were unchanged in this study. These data indicate that PMV produces favorable hemostatic effects when sufficient mitral valve dilatation is achieved. Analysis of our data also discloses that platelet activation plays an important role in the initial step of thrombus formation in patients with rheumatic mitral stenosis.

Excessive vasoconstriction in rheumatic mitral stenosis with modestly reduced ejection fraction

OBJECTIVES

The primary hypothesis examined was that underfilling due to inflow obstruction accounts for modestly depressed ejection performance in mitral stenosis. Having found little evidence to support this hypothesis, we sought to determine other factors that might differentiate patients with different levels of ejection performance.

METHODS

Ventricular load and performance were compared in two groups of patients before and immediately after successful balloon valvuloplasty that was not complicated by mitral regurgitation: those in whom prevalvuloplasty ejection fraction was > or = 0.55 (group I, n = 10) and those in whom it was < 0.55 (group II, n = 11).

RESULTS

Before valvuloplasty, mitral valve area was less in group II (0.65 cm2) than in group I (0.84 cm2, p = 0.02), but end-diastolic pressure (12 vs. 12 mm Hg in group I), end-diastolic wall stress (46 vs. 44 kdynes/cm2 in group I) and end-diastolic volume (152 vs. 150 ml in group I) were not less in group II, nor were these variables significantly reduced compared with those of a normal control group. In group II, end-systolic volume was larger (77 vs. 55 ml in group I, p = 0.001) and cardiac output was less (3.1 vs. 3.6 liters/min in group I, p = 0.03), possibly owing to higher systemic vascular resistance (2,438 vs. 1,921 dynes.s.cm-5 in group I, p = 0.05) and end-systolic wall stress (273 vs. 226 kdynes/cm2 in group I, p = 0.06), although mean arterial pressure in the two groups was similar (91 vs. 84 mm Hg in group I, p = 0.22). Group II patients also had higher values for pulmonary vascular resistance (712 vs. 269 dynes.s.cm-5 in group I, p = 0.03) and mean pulmonary artery pressure (47 vs. 29 mm Hg in group I, p = 0.02) despite similar values for mean left atrial pressure (20 vs. 18 mm Hg in group I, p = 0.35). After valvuloplasty, mitral valve area increased by 2.5- and 3-fold, respectively, in group I (to 2.1 cm2) and group II (to 2.0 cm2). Modest increases in left ventricular end-diastolic pressure, end-diastolic stress and end-diastolic volume (+9%) after valvuloplasty were statistically significant only for group II. End-systolic wall stress did not decline in either group II (281 kdynes/cm2) or group I (230 kdynes/cm2), and ejection fraction failed to increase significantly (0.49 to 0.51 for group II and 0.62 to 0.61 for group I) after valvuloplasty. Contractile performance estimated with a preload-corrected ejection fraction-afterload relation was within or near normal limits in all 19 patients in whom it was assessed.

CONCLUSIONS

Excessive vasoconstriction may account for the higher afterload, lower ejection performance and lower cardiac output observed in a subset of patients with mitral stenosis because contractile dysfunction could not be detected and left ventricular filling--which was not subnormal despite severe inflow obstruction--improved only modestly after valvuloplasty.

Predictors of long-term outcome after percutaneous balloon mitral valvuloplasty

BACKGROUND

Percutaneous balloon mitral valvuloplasty is known to produce short-term hemodynamic and symptomatic improvement in many patients with mitral stenosis. Comprehensive assessment of the clinical usefulness of balloon valvuloplasty requires evaluation of patients' long-term outcomes.

METHODS

We performed balloon mitral valvuloplasty in 146 patients between October 1, 1985, and October 1, 1991. Base-line demographic, clinical, echocardiographic, and hemodynamic variables were evaluated in order to identify predictors of long-term event-free survival.

RESULTS

Balloon mitral valvuloplasty was completed successfully in 136 (93 percent) of the patients in whom the procedure was attempted; it resulted in an increase in the mean (+/- SD) mitral-valve area from 1.0 +/- 0.4 to 2.1 +/- 0.9 cm2 and a decrease in the mean transmitral pressure gradient from 14 +/- 5 to 6 +/- 3 mm Hg (P < 0.001 for both comparisons). The estimated overall five-year survival rate was 76 +/- 5 percent, and the estimated five-year event-free survival rate (the percentage of patients without mitral-valve replacement, repeat valvuloplasty, or death from cardiac causes) was 51 +/- 6 percent. According to multivariate Cox proportional-hazards analysis, the independent predictors of longer event-free survival were a lower mitral-valve echocardiographic score (a measure of mitral-valve deformity; range, 0 for a normal valve to 16 for a seriously deformed valve; P < 0.001), lower left ventricular end-diastolic pressure (P = 0.001), and a lower New York Heart Association (NYHA) functional class (P = 0.04). Patients with no risk factors for early restenosis or only one risk factor (echocardiographic score > 8, left ventricular end-diastolic pressure > 10 mm Hg, or NYHA functional class IV) had a predicted five-year event-free survival rate of 60 to 84 percent, whereas patients with two or three risk factors had a predicted five-year event-free survival rate of only 13 to 41 percent.

CONCLUSIONS

Balloon mitral valvuloplasty as a treatment for selected patients with mitral stenosis has good long-term results. The long-term outcome after this procedure can be predicted on the basis of patients' base-line characteristics.

Cardiopulmonary exercise testing early after catheter-balloon mitral valvuloplasty in patients with mitral stenosis

Seven female patients (age 27 to 53 yr) with significant mitral stenosis performed continuous, incremental, maximal treadmill exercise tests the day before and within 3-5 days after catheter-balloon valvuloplasty. Mitral valve area determined by the echo-Doppler method increased from 0.9 +/- 0.3 cm2 to 1.9 +/- 0.7 cm2 (p < 0.02). Mean left atrial pressure was reduced from 24 +/- 8 to 13 +/- 7 mmHg (p < 0.01) and mean pulmonary artery pressure from 36 +/- 13 to 28 +/- 10 mmHg (p < 0.02) with a non-significant increase in cardiac output from 3.6 +/- 1.2 to 4.0 +/- 1.7 l/min. After catheter-balloon valvuloplasty all patients reached a higher maximal workload during exercise, and mean value of oxygen consumption and pulmonary ventilation were significantly lower in submaximal workloads. The calculated ventilatory equivalent for oxygen was significantly reduced in submaximal and in maximal workloads after catheter-balloon valvuloplasty. Peak oxygen consumption and the ventilatory anaerobic threshold were not changed after catheter-balloon valvuloplasty (pre 15.59 +/- 2.72 vs post 16.90 +/- 3.44 and pre 12.10 +/- 2.55 vs post 12.62 +/- 2.71 ml/kg/min, respectively). We concluded that after catheter-balloon valvuloplasty the cost of breathing was reduced and the oxygen consumed was more effectively utilized during exercise. Increases in peak oxygen consumption and in ventilatory anaerobic threshold would require circulatory and metabolic adaptations in response to increased physical activity and were not observed when cardiopulmonary tests were performed early after catheter-balloon valvuloplasty.

Interpretation of cardiac pathophysiology from pressure waveform analysis: mitral valve gradients: Part II

Balloon mitral commissurotomy in many patients will be as satisfactory as closed surgical commissurotomy. Data from combined hemodynamic and echocardiographic techniques elegantly elucidate the mechanisms of mitral valve flow and pathophysiology of disturbed pressure relationships between the left atrial and left ventricular chambers, both before and after balloon valvuloplasty. The pulmonary capillary wedge pressure may not be satisfactory to assess the success of gradient reduction after mitral valvuloplasty.

Influence of mitral valve morphology on mitral balloon commissurotomy: immediate and six-month results from the NHLBI Balloon Valvuloplasty Registry

Echocardiographic data were analyzed in 555 patients undergoing mitral balloon commissurotomy (MBC). Patients were enrolled in the National Heart, Lung, and Blood Institute Balloon Valvuloplasty Registry from 24 centers. There were 456 women and 99 men with a mean age of 54 years. Before MBC the two-dimensional echocardiographic variables of mitral valve thickness, mobility, calcification, and subvalvular disease were evaluated and assigned scores of 1 to 4. The mitral valve morphology score was related to mitral valve area (MVA) measured after MBC by cardiac catheterization. The leaflet mobility score was related to the immediate post-MBC MVA: 2.2 +/- 0.8 cm2 for grade 1, 1.9 +/- 0.7 cm2 for grade 2, 1.7 +/- 0.7 cm2 for grade 3, and 1.9 +/- 0.9 cm2 for grade 4 (p less than 0.001). Results of the MVA after MBC showed a similar relationship for each echocardiographic variable. The total morphology score (sum of the four variables) showed a weak relationship to MVA immediately after MBC (r = 0.24), which was persistent at 6 months after MBC (r = -0.25). Multiple regression analysis showed that the MVA after MBC is predicted by pre-MBC MVA (p less than 0.001), left atrial size (p = 0.01), balloon diameter (p = 0.02), cardiac output (p = 0.004), and leaflet mobility (p = 0.01). The R2 of the model was 0.31 (p less than 0.001). Total morphology score, leaflet thickness, calcification, and subvalvular disease were not important univariate or multivariate predictors of the results of MBC.(ABSTRACT TRUNCATED AT 250 WORDS)

Immediate effects of percutaneous transvenous mitral commissurotomy on pulmonary hemodynamics at rest and during exercise in mitral stenosis

Hemodynamics were evaluated during exercise in 33 patients with mitral stenosis who underwent percutaneous transvenous mitral commissurotomy (PTMC). PTMC was performed using an Inoue balloon. Each patient underwent a supine ergometer exercise test before and on the day after PTMC. Ergometer work load was started at 20 W and increased in increments of 20 W at 3-minute intervals until terminated by the patient's fatigue or shortness of breath. Mitral valve area increased by 0.8 +/- 0.4 cm2 (1.1 +/- 0.3 to 1.9 +/- 0.4 cm2, p less than 0.001). Mean mitral pressure gradient decreased (12 +/- 5 to 6 +/- 2 mm Hg, p less than 0.001). Pulmonary arterial pressure significantly decreased and the cardiac index significantly increased both at rest and during exercise after PTMC. Before PTMC, the increases in pulmonary arterial pressure, total pulmonary resistance and pulmonary arteriolar resistance during exercise were greater in patients with a mitral valve area less than 1.0 cm2 than in patients with an area greater than or equal to 1.0 cm2. After PTMC, total pulmonary resistance still increased during exercise. However, pulmonary arteriolar resistance did not change during exercise in patients with a mitral valve area greater than or equal to 1.5 cm2, whereas it increased in patients with an area less than 1.5 cm2. An enlarged mitral valve area greater than or equal to 1.5 cm2, which may prevent pulmonary vasoconstriction and permits a greater increase in pulmonary blood flow during exercise, is considered a good result immediately after PTMC.

Interpretation of cardiac pathophysiology from pressure waveform analysis: mitral valve gradients: Part I

The mitral valve gradient is dependent on the precise measurement of left atrial (or pulmonary capillary wedge) and left ventricular pressures. Artifacts involving either pressure measurement will produce inaccuracies which may have clinical significance. Several methods and formulas using both invasive and noninvasive techniques should verify clinical findings and confirm the severity of mitral valve disease prior to definite therapy. The changes in mitral valve gradients after balloon catheter valvuloplasty will be discussed in part II of this hemodynamic rounds.

Comparison of Inoue single-balloon versus double-balloon technique for percutaneous mitral valvotomy

The results of percutaneous mitral valvotomy by means of the Inoue single-balloon (N = 85, group 1) and the double-balloon (N = 322, group 2) techniques were compared in a nonrandomized study. The groups were not significantly different with regard to age, sex, calcification, or hemodynamic values before percutaneous mitral valvotomy. After percutaneous mitral valvotomy, patients in both groups had significant hemodynamic and clinical improvement. The increases in mitral valve area and cardiac output and the decreases in mitral valve gradient, mean pulmonary artery pressure, and mean left atrial pressure were greater in group 2. Mitral valve area determined by the Gorlin method increased 191% in group 2 and 106% in group 1; Doppler-determined mitral valve area increased 133% in group 2 and 98% in group 1. Optimal results were achieved in 93% of the patients in group 2 and 76% in group 1 (p less than or equal to 0.0001). In group 1, 6% of patients had a left-to-right shunt as shown by angiography versus 14% in group 2 (p less than or equal to 0.05). In group 2, 46% of patients had at least a 1+ increase in mitral regurgitation versus 52% in group 1. Among the patients who had an increase in mitral regurgitation, 36% of those in group 1 versus 9% in group 2 had a 2+ or more increase (p less than or equal to 0.001). The mean balloon diameter to anulus ratio was larger in group 2, and the larger the balloon diameter to anulus ratio, the greater the increase in mitral valve area.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular perforation during percutaneous balloon mitral valvuloplasty

Percutaneous balloon mitral valvuloplasty has been reported to be complicated by left ventricular perforation with fatal results. We report two cases of left ventricular perforation following balloon mitral valvuloplasty. In one patient left ventricular perforation occurred silently without any hemodynamic sequelae and was only detected at left ventricular angiography after valvuloplasty. In the second patient left ventricular perforation was caused by the mitral dilating balloon catheter. The subsequent tamponade was relieved by immediate aspiration with hemodynamic stabilization thereafter. Neither patient required surgery. Both patients are well 6 mon after the procedure. We discuss the mechanism of this serious complication in these two patients.

Intracardiac echocardiography during simulated aortic and mitral balloon valvuloplasty: in vivo experimental studies

The feasibility of intracardiac echocardiography with a low-frequency transducer to assess catheter position and detect complications during experimental aortic and mitral balloon valvuloplasty was studied in 10 dogs. Intracardiac echocardiography was performed with a transesophageal echocardiographic probe placed in the right atrium. In all instances high-quality images of cardiac structures were obtained. The guide wire and balloon catheter were clearly seen as they crossed the valves. With inflation the balloon was seen as a hyperechoic structure. Doppler echocardiography documented aortic regurgitation after inflations. Acute pericardial effusion was instantly detected. It is concluded that intracardiac echocardiography is a potentially useful technique for cardiac imaging, assessing wire and balloon catheter position, evaluating valvular regurgitation, and instantly detecting acute pericardial effusion. Further research in humans with low-frequency, catheter-based transducers needs to be performed.

Percutaneous mitral valvotomy with the Inoue balloon catheter in children and adults: immediate results and early follow-up

Percutaneous mitral balloon valvotomy (PMV) using the Inoue balloon catheter was attempted in 60 consecutive patients with severe symptomatic mitral stenosis. There were 10 children (mean age 13 years) and 50 adults (mean age 31 years). Forty patients were females and 20 were males; 53 were in sinus rhythm. The procedure was technically successfully performed in 57 (95%) patients. There were no deaths or thromboembolic complications. Balloon valvotomy was done using a 22 to 30 mm diameter catheter with the echo/Doppler guided stepwise mitral dilatation technique. After PMV the mean left atrial pressure decreased from 23.0 +/- 5.0 to 14.0 +/- 4.0 mm Hg (p less than 0.001). The mean mitral valve gradient (MVG) decreased from 15.0 +/- 4.0 to 6.0 +/- 2.0 mm Hg (p less than 0.001). The mitral valve area (Gorlin formula) increased from 0.7 +/- 0.2 to 1.6 +/- 0.4 cm2 (p less than 0.001). The mitral valve area as determined by echocardiography increased from 0.8 +/- 0.1 to 1.9 +/- 0.3 cm2 (p less than 0.001). Mild mitral regurgitation (MR) developed in six patients (11%) and increased by one grade in another five patients (9%). No patient developed severe mitral regurgitation. Mitral valve area at mean follow-up of 4.8 months remained unchanged at 1.9 +/- 0.3 cm2. We conclude that PMV, using the Inoue balloon catheter, is safe and effective in the treatment of severe mitral stenosis in children and adults, without inducing significant mitral regurgitation.

Left ventricular filling and ventricular diastolic performance after percutaneous balloon mitral valvotomy

The time course of left ventricular (LV) filling and LV diastolic performance were examined in 27 consecutive patients in sinus rhythm before and acutely after balloon mitral valvotomy (BMV). The mitral valve area acutely increased from 1.1 +/- 0.3 to 2.1 +/- 0.8 cm2. Simultaneous pressure-volume data were obtained using digital subtraction left ventriculography and LV micromanometer pressure before and 10 minutes after BMV. The time constant of LV isovolumic relaxation was unchanged after BMV (50 +/- 10 ms before BMV vs 47 +/- 13 ms after BMV). In addition, values before and after BMV for LV end-diastolic volume (123 +/- 29 vs 125 +/- 36 ml), end-diastolic pressure (11 +/- 4 vs 12 +/- 4 mm Hg) and diastolic filling time (337 +/- 126 vs 338 +/- 152 ms) were not altered by the procedure. After BMV the peak diastolic filling rate (403 +/- 143 vs 469 +/- 302 ml/s) was maintained despite a 36% reduction in left atrial filling pressure. There was a trend toward earlier occurrence of the peak filling rate (196 +/- 127 vs 146 +/- 148 ms, p = 0.08). The percentage of diastolic filling in the first third of diastole, however, was similar (42 +/- 9 vs 48 +/- 16%) before and after the procedure. Thus, the time course of LV filling is not significantly altered acutely after BMV, but is maintained at reduced left atrial filling pressure. Neither LV relaxation or LV chamber compliance are altered acutely after BMV.(ABSTRACT TRUNCATED AT 250 WORDS)

Interpretation of cardiac pathophysiology from pressure waveform analysis: percutaneous balloon valvuloplasty

The hemodynamic findings of aortic, mitral and pulmonary balloon valvuloplasty serve to identify classical valvular lesions and their responses to graded or abrupt catheter dilation techniques. The production of mild insufficiency after valve dilation is generally well tolerated. Severe valvular insufficiency produces the expected hemodynamic alterations, but acute decompensation may be witnessed over brief periods of time. The use of extra stiff guidewires across dilated valves, especially the aortic valve, may also produce an exaggerated hemodynamic picture of insufficiency. Although gradients may be reduced, the effect of valve dilation on aortic valve area is generally small. A discussion of factors influencing valve area calculations will be the subject of a future "Rounds."

Percutaneous mitral valvuloplasty following surgical repair of sinus venosus atrial septal defect

Mitral valvuloplasty performed 5 y after repair of a sinus venosus ASD was difficult because of a thickened septum, but resulted in improved mitral valve opening and did not lead to ASD. Thus, prior repair of a sinus venosus ASD may not be an absolute contraindication to mitral valvuloplasty.

Percutaneous balloon mitral valvuloplasty in rheumatic mitral stenosis: an experience of 50 patients in India

We attempted percutaneous balloon mitral valvuloplasty in 50 patients (27 female and 23 male, age 10-38 years) with rheumatic mitral stenosis. The procedure could be completed in 40 patients. The failures were caused by problems related to transseptal puncture in eight cases and inability to cross the mitral valve in two cases. Immediately after valvuloplasty there was a remarkable reduction in the mean pulmonary artery pressure, left atrial mean pressure, mean diastolic gradient across the mitral valve, and the calculated pulmonary vascular resistance. The calculated mitral valve area increased and the cardiac index increased marginally. Inadequate results with a post valvuloplasty mitral valve area of 0.9 cm2 were seen in only one patient. Repeat hemodynamic evaluation in 25 patients within two weeks of valvuloplasty showed persistent benefit in all except one patient, who showed partial restenosis. Follow-up cardiac catheterization at 3-6 months in 13 patients showed evidence of restenosis (mitral valve area less than 1.0 cm2 and mean diastolic gradient of greater than 10 mmHg) in one patient, while all others maintained hemodynamic benefit. Repeat hemodynamic evaluation at 9-18 months after valvuloplasty in eight patients showed evidence of restenosis in an additional two cases. The patients in our series are young (28 patients less than 20 years), small body surface area (1.35-0.2 m2), and have high left atrial and pulmonary arterial pressures.

Effects of percutaneous transvenous mitral commissurotomy on levels of plasma atrial natriuretic peptide during exercise

To clarify the factors that influenced the secretion of human atrial natriuretic peptide (ANP) during exercise, we studied the relations between the changes in ANP, transmitral pressure gradient, heart rate and blood pressure at exercise in 16 patients with mitral stenosis before and after percutaneous transvenous mitral commissurotomy (PTMC). Before PTMC, ANP levels increased from 107 +/- 70 to 183 +/- 96 pg/ml during exercise testing (p less than 0.01), concomitant with the increment in mean transmitral pressure gradient, heart rate and systolic blood pressure. After PTMC, ANP levels also increased from 78 +/- 43 to 117 +/- 64 pg/ml, concomitant with the increment of those parameters. However, increments of ANP, mean transmitral pressure gradient and heart rate after PTMC were lower than those before PTMC. Because the most important factor influencing the secretion of ANP was unclear, the differences between these parameters were calculated at submaximal exercise before and after PTMC. There was a significant relation only between the change in ANP and mean transmitral pressure gradient (r = 0.70, p less than 0.01). These results suggest that the most important factor influencing the secretion of ANP during exercise is the change in transmitral pressure gradient in patients with mitral stenosis.

Management of valvular heart disease: an illustrative cases approach

As indicated by the 22 illustrative cases included in this monograph, a stepwise approach to the assessment of valvular heart disease provides the information necessary to make good clinical decisions. The ECG and chest x-ray add useful information to the history and physical examination. Echocardiography, Doppler, and color flow Doppler techniques have an important role in defining the presence and severity of valvular stenosis and regurgitation. Nuclear techniques provide useful information about global biventricular systolic function, regional wall motion, and myocardial perfusion. Exercise testing is most valuable in confirming objectively the patient's functional status and exercise tolerance. Newer imaging techniques, such as cine CT and MRI, are capable of displaying and measuring cardiac chamber size and myocardial thickness; however, visualization of the cardiac valves and demonstration of flow abnormalities are difficult, limiting the current usefulness of these techniques in patients with valvular heart disease.

Factors influencing progression of mitral regurgitation after transarterial balloon valvuloplasty for mitral stenosis

This study analyzes the clinical, echocardiographic and hemodynamic factors affecting progression of mitral regurgitation (MR) after transarterial balloon valvuloplasty in 200 consecutive patients with rheumatic mitral stenosis. After valvuloplasty, the mitral valve area increased in all patients, from 1.03 +/- 0.36 to 2.06 +/- 0.71 cm2 (p less than 0.0001). With regard to the basal stage, the mitral valve was competent in 139 patients and there was mild MR in 61 (grade I in 53, and grade II in 8). Three patients had progression of MR induced by a technical deficiency and they were excluded from analysis. Patients were classified into 2 groups on the basis of the degree of MR before and after valvuloplasty: group A--no progression of MR (n = 167; 85%) when the degree of MR did not change, disappeared after valvuloplasty, or increased from grade 0 to I; group B--progression of MR (n = 30; 15%) when the degree of MR increased to greater than or equal to grade II. Progression of MR was observed more frequently in older patients with presence of chronic atrial fibrillation, larger left atrial size and left ventricular volumes, baseline MR, more severe stenosis and a lower ejection fraction. Multivariate analysis selected age, left ventricular volumes and ejection fraction as independent predictors of progression of MR. All these factors suggest that progression of MR after balloon valvuloplasty could be related to a more advanced degree of disease.