Immediate and long-term effect of mitral balloon valvotomy on left ventricular volume and systolic function in severe mitral stenosis

Pulmonary artery pressure response to percutaneous mitral valvuloplasty: Associated factors and clinical implications

BACKGROUND

Pulmonary hypertension (PH) is a marker of poor outcome in mitral stenosis (MS), which improves after percutaneous mitral valvuloplasty (PMV). However, mechanical interventions for relief of valve obstruction often but not always reduce pulmonary pressures. This study aimed to assess the parameters associated with abnormal pulmonary artery pressure (PAP) response immediately after a successful PMV, and also its impact on long-term outcome.

METHODS

A total of 181 patients undergoing PMV for rheumatic MS were prospectively enrolled. Invasive hemodynamic and echocardiographic measures were examined in all patients. Abnormal PAP response was defined as the mean PAP (mPAP) values unchanged at the end of the procedure. Long-term outcome was a composite endpoint of death, mitral valve replacement, repeat PMV, new onset of atrial fibrillation (AF), or stroke.

RESULTS

The mean age was 44.1 ± 12.6 years, and 157 patients were women (86.7%). In the overall population, mPAP decreased from 33.4 ± 13.1 mmHg pre to 27.6 ± 9.8 mmHg post (p < 0.001). Following PMV, 52 patients (28.7%) did not have any reduction of mPAP immediately after the PMV. Multivariable analysis adjusting for baseline values of PAP and mitral valve area revealed that AF (Odds ratio [OR] 2.7, 95% [confidence interval] CI 1.3 to 6.7), maximum mitral valve leaflets displacement (OR 0.8, 95% CI 0.7 to 0.9), and post-procedural left ventricular compliance (OR 0.7, 95% CI 0.5 to 0.9) were predictors of a lack of improvement in mPAP. During a median follow-up of 4.4 years, the endpoint was reached in 56 patients (31%). The pulmonary pressure response to PMV was not an independent predictor of long-term events.

CONCLUSIONS

In patients with MS undergoing PMV, pulmonary pressures may not reduce immediately after the procedure, despite adequate opening of the valve. Abnormal PAP response can be predicted from baseline clinical and valvular characteristics as well as post-procedural left ventricular compliance. The lack of any immediate reduction in mPAP is not associated with long-term adverse outcomes.

Impact of percutaneous mitral valvuloplasty on left ventricular function in patients with mitral stenosis assessed by 3D echocardiography

BACKGROUND

The status of intrinsic left ventricular (LV) contractility in patients with isolated rheumatic mitral stenosis (MS) has been debated. The acute changes in loading conditions after percutaneous mitral valvuloplasty (PMV) may affect LV performance. We aimed to examine the acute effects of PMV on LV function and identify factors associated with LV ejection fraction (LVEF) changes, and determinants of long-term events following the procedure.

METHODS

One hundred and forty-two patients who underwent PMV for symptomatic rheumatic MS (valve area of 0.99±0.3cm²) were prospectively enrolled. LV volumes and LVEF were measured by three-dimensional (3D) echocardiography. Long-term outcome was a composite endpoint of death, mitral valve (MV) replacement, repeat PMV, new onset of atrial fibrillation, and stroke.

RESULTS

The mean age was 42.3±12.1years, and 125 patients were women (88%). After PMV, LVEF increased significantly (51.4 vs 56.5%, p<0.001), primary due to a significant increase in LV end-diastolic volume (65.8mL vs 67.9mL, p=0.002), and resultant increase in the stroke volume (33.9mL vs 39.6mL, p<0.001). Changes in cardiac index and systolic pulmonary artery pressure were associated with LVEF changes after PMV. During a mean follow-up period of 30.8months, 28 adverse clinical events were observed. Postprocedural mitral regurgitation, MV area, and mean gradient were independent predictors of composite endpoints.

CONCLUSIONS

In patients with rheumatic MS, PMV resulted in a significant improvement in LV end-diastolic volume, stroke volume and consequently increased in LVEF. Changes in cardiac index and systolic pulmonary artery pressure were associated with LVEF changes after PMV. The predictors of long-term adverse events following PMV were post-procedural variables, including mitral regurgitation, valve area, and mean gradient.

Mitral balloon valvuloplasty

Percutaneous mitral balloon valvuloplasty (MBV) was introduced in 1984 by Inoue who developed the procedure as a logical extension of surgical closed commissurotomy. Since then, MBV has emerged as the treatment of choice for severe pliable rheumatic mitral stenosis (MS). With increasing experience and better selection of patient, the immediate results of the procedure have improved and the rate of complications declined. When the reported complications of MBV are viewed in aggregate, complications occur at approximately the following rates: mortality (0-0.5%), cerebral accident (1-2%), mitral regurgitation (MR) requiring surgery (1.6-3%). These complication rates compare favorably to those reported after surgical commissurotomy. Several randomized trials reported similar hemodynamic results with MBV and surgical commissurotomy. Restenosis after MBV ranges from 4% to 70% depending on the patient selection, valve morphology, and duration of follow-up. Restenosis was encountered in 31% of the author's series at mean follow-up 9 ± 5.2 years (range 1.5-19 years) and the 10, 15, and 19 years restenosis-free survival rates were (78 ± 2%) (52 ± 3%) and (26 ± 4%), respectively, and were significantly higher for patients with favorable mitral morphology (MES ⩽ 8) at 88 ± 2%, 67 ± 4% and 40 ± 6%), respectively (P < 0.0001). The 10, 15, and 19 years event-free survival rates were (88 ± 2%, 60 ± 4% and 28 ± 7%, respectively, and were significantly higher for patients with favorable mitral morphology (92 ± 2%, 70 ± 4% and 42 ± 7%, respectively (P < 0.0001). The effect of MBV on severe pulmonary hypertension, concomitant severe tricuspid regurgitation, left ventricular function, left atrial size, and atrial fibrillation are addressed in this review. In addition, the application of MBV in specific clinical situations such as in children, during pregnancy and for restenosis is discussed.

Percutaneous mitral balloon valvotomy

Percutaneous mitral balloon valvotomy (PMBV) was introduced in 1984 by Inoue who developed the procedure as a logical extension of surgical closed commissurotomy. Since then, PMBV has emerged as the treatment of choice for severe pliable rheumatic mitral stenosis (MS). With increasing experience and better selection of patient, the immediate results of the procedure have improved and the rate of complications declined. When the reported complications of PMBV are viewed in aggregate, complications occur at approximately the following rates: mortality (0-0.5%), cerebral accident (0.5-1%), mitral regurgitation (MR) requiring surgery (1.6-3%). These complication rates compare favorably to those reported after surgical commissurotomy. Several randomized trials reported similar hemodynamic results with PMBV and surgical commissurotomy. Restenosis after PMBV ranges from 4 to 70% depending on the patient selection, valve morphology, and duration of follow up. Restenosis was encountered in 21% of the author's series at mean follow-up 6 +/- 4.5 years and the 10 and 15 years restenosis-free survival rates were (70 +/- 3)% and (44 +/- 5)%, respectively, and were significantly higher for patients with favorable mitral morphology (85 +/- 3% and 65 +/- 6%), respectively (P < 0.0001). The 10 and 15 years event-free survival rates were (79 +/- 2)% and (43 +/- 9)% and were significantly higher for patients with favorable mitral morphology (88 +/- 2)% and (66 +/- 6)%, respectively (P < 0.0001). The effect of PMBV on severe pulmonary hypertension, concomitant severe tricuspid regurgitation, left ventricular function, left atrial size, and atrial fibrillation are addressed in this review. In addition, the application of PMBV in specific clinical situations such as in children, during pregnancy and for restenosis is discussed.

Effects of percutaneous mitral commissurotomy on longitudinal left ventricular dynamics in mitral stenosis: Quantitative assessment by tissue velocity imaging

OBJECTIVE

We hypothesized that mitral annular velocities would improve immediately after relief of mitral stenosis and that serial assessment could be used as an index for quantifying functional changes after percutaneous mitral commissurotomy (PMC).

METHODS

Longitudinal left ventricular annular velocities were quantified by spectral pulsed wave Doppler tissue velocity imaging in 25 patients (16 women; mean age [+/-SD], 29.2 +/- 8.6 years) who had isolated mitral stenosis and were in sinus rhythm, and were compared with 30 age- and sex-matched control subjects. Echocardiography was performed 1 to 24 hours before PMC and 48 to 72 hours after, and changes in velocities from the lateral and septal corners of the mitral annulus in early diastole, late diastole, isovolumic contraction, and ejection were recorded.

RESULTS

Systolic and diastolic mitral annular velocities were significantly less in patients with mitral stenosis than in control subjects. After PMC, peak annular velocity of systolic excursion in ejection and peak annular velocity in early diastole showed significant improvement. The change in peak annular velocity in early diastole in the lateral wall correlated well with improvement in the mitral valve orifice area by planimetry (ratio of mitral valve orifice area, 1.92 +/- 0.42; ratio of peak annular velocity in early diastole, 1.36 +/- 0.22; r = 0.65; P <.001).

CONCLUSION

Serial evaluation of changes in mitral annular velocities by Doppler tissue imaging aids clinical assessment of immediate improvement in left ventricular function after PMC.

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.