Predictors of developing significant mitral regurgitation following percutaneous mitral commissurotomy with inoue balloon technique

Assessment of suitability for percutaneous mitral commissurotomy: a contemporary review of key anatomical criteria and predictive models

The immediate result of percutaneous balloon mitral commissurotomy is largely determined by the anatomy of the mitral valve complex. Several scores and models have been developed to assess anatomical suitability for percutaneous balloon mitral commissurotomy. Although none has an optimal predictive power, these models look at the valvular apparatus from different perspectives bearing the potential for a complementary role.

Proinflammatory Matrix Metalloproteinase-1 Associates With Mitral Valve Leaflet Disruption Following Percutaneous Mitral Valvuloplasty

Mitral regurgitation (MR) is a major complication of the percutaneous mitral valvuloplasty (PMV). Despite high technical expertise and cumulative experience with the procedure, the incidence rate of severe MR has not decreased. Although some of MR can be anticipated by echocardiographic analysis; leaflet tearing, which leads to the most dreaded type of MR, remains unpredictable. Irregular valvular collagen remodeling is likely to compromise tissue architecture and increase the tearing risk during PMV balloon inflation. In this study, we evaluated histological and molecular characteristics of excised mitral valves from patients with rheumatic mitral stenosis (MS) who underwent emergency surgery after PMV due to severe MR caused by leaflet tear. Those findings were compared with patients who underwent elective mitral valve replacement surgery owing to severe MS, in whom PMV was not indicated. In vitro assay using peripheral blood mononuclear cells was performed to better understand the impact of the cellular and molecular alterations identified in leaflet tear mitral valve specimens. Our analysis showed that focal infiltration of inflammatory cells contributes to accumulation of MMP-1 and IFN-γ in valve leaflets. Moreover, we showed that IFN-γ increase the expression of MMP-1 in CD14⁺ cells (monocytes) in vitro. Thus, inflammatory cells contribute to unevenly remodel collagen resulting in variable thickening causing abnormalities in leaflet architecture making them more susceptible to laceration.

Comparison of early and long-term follow-up results of percutaneous mitral balloon valvuloplasty and mitral valve replacement

BACKGROUND

Percutaneous mitral balloon valvuloplasty and mitral valve replacement have been the treatment options for mitral stenosis for several years, however, studies that compare these two modalities are very rare in the literature.

OBJECTIVE

In this article, we aim to investigate the comparison of clinical results of percutaneous mitral balloon valvuloplasty and mitral valve replacement.

METHODS

527 patients with rheumatic mitral stenosis, treated with percutaneous mitral balloon valvuloplasty or mitral valve replacement (276 patients with percutaneous mitral balloon valvuloplasty and 251 patients with mitral valve replacement) from 1991 to 2012 were evaluated. The demographic characteristics, clinical, echocardiographic and catheterization data of patients were evaluated retrospectively. The results of early and late clinical follow-up of patients after percutaneous mitral balloon valvuloplasty and mitral valve replacement were also evaluated.

RESULTS

The mean follow-up time of the percutaneous mitral balloon valvuloplasty group was 4.7 years and, for the mitral valve replacement-group, it was 5.45 years. The hospital stay of the percutaneous mitral balloon valvuloplasty group was shorter than that of the mitral valve replacement group (2.02 days vs 10.62 days, p<0.001). The hospital mortality rate of percutaneous mitral balloon valvuloplasty and mitral valve replacement were 0% and 2% respectively (p=0.024). In the percutaneous mitral balloon valvuloplasty group, early postprocedural success rate was 92.1%. The event-free survival of percutaneous mitral balloon valvuloplasty and mitral valve replacement was found to be similar. While reintervention was higher in percutaneous mitral balloon valvuloplasty-group (p<0.001), mortality rate was higher in mitral valve replacement-group (p<0.001).

CONCLUSION

Percutaneous mitral balloon valvuloplasty seems to be more advantageous than mitral valve replacement due to low mortality rates, easy application of the procedure and no need for general anesthesia.

Mitral Regurgitation After Percutaneous Mitral Valvuloplasty: Insights Into Mechanisms and Impact on Clinical Outcomes

OBJECTIVES

The aim of this study was to assess the incidence, mechanisms, and outcomes of mitral regurgitation (MR) after percutaneous mitral valvuloplasty (PMV).

BACKGROUND

Significant MR continues to be a major complication of PMV, with a wide range in clinical presentation and prognosis.

METHODS

Consecutive patients with mitral stenosis undergoing PMV were prospectively enrolled. MR severity was evaluated by using quantitative echocardiographic criteria, and its mechanism was characterized by 3-dimensional transesophageal echocardiography, divided broadly into 4 categories based on the features contributing to the valve damage. B-type natriuretic peptide levels were obtained before and 24 h after the procedure. Endpoints estimated cardiovascular death or mitral valve (MV) replacement due to predominant MR.

RESULTS

A total of 344 patients, ages 45.1 ± 12.1 years, of whom 293 (85%) were women, were enrolled. Significant MR after PMV was found in 64 patients (18.6%). The most frequent mechanism of MR was commissural, which occurred in 22 (34.4%) patients, followed by commissural with posterior leaflet in 16 (25.0%), leaflets at central scallop or subvalvular damage in 15 (23.4%), and central MR in 11 (17.2%). During the mean follow-up period of 3 years (range 1 day to 10.6 years), 60 patients reached the endpoint. The event-free survival rates were similar among patients with mild or commissural MR, whereas patients with damaged central leaflet scallop or subvalvular apparatus had the worst outcome, with an event-free survival rate at 1 year of only 7%. Long-term outcome was predicted by net atrioventricular compliance (C_n) at baseline and post-procedural variables, including valve area, mean gradient, and magnitude of decrease in B-type natriuretic peptide levels, adjusted for the mechanism of MR.

CONCLUSIONS

Significant MR following PMV is a frequent event, mainly related to commissural splitting, with favorable clinical outcome. Parameters that express the relief of valve obstruction and the mechanism by which MR develops were predictors of long-term outcomes.

Predictors of Long-Term Outcomes of Percutaneous Mitral Valvuloplasty in Patients with Rheumatic Mitral Stenosis

PURPOSE

We determined factors associated with long-term outcomes of patients who underwent successful percutaneous mitral balloon valvuloplasty (PMV).

MATERIALS AND METHODS

Between August 1980 and May 2013, 1187 patients underwent PMV at Severance Hospital, Seoul, Korea. A total of 742 patients who underwent regular clinic visits for more than 10 years were retrospectively analyzed. The endpoints consisted of repeated PMV, mitral valve (MV) surgery, and cardiovascular-related death.

RESULTS

The optimal result, defined as a post-PMV mitral valve area (MVA) >1.5 cm² and mitral regurgitation ≤Grade II, was obtained in 631 (85%) patients. Over a mean follow up duration of 214±50 months, 54 (7.3%) patients underwent repeat PMV, 4 (0.5%) underwent trido-PMV, and 248 (33.4%) underwent MV surgery. A total of 33 patients (4.4%) had stroke, and 35 (4.7%) patients died from cardiovascular-related reasons. In a multivariate analysis, echocardiographic score [p=0.003, hazard ratio=1.56, 95% confidence interval (CI): 1.01-2.41] and post-MVA cut-off (p<0.001, relative risk=0.39, 95% CI: 0.37-0.69) were the only significant predictors of long-term clinical outcomes after adjusting for confounding variables. A post-MVA cut-off value of 1.76 cm² showed satisfactory predictive power for poor long-term clinical outcomes.

CONCLUSION

In this long-term follow up study (up to 20 years), an echocardiographic score >8 and post-MVA ≤1.76 cm² were independent predictors of poor long-term clinical outcomes after PMV, including MV reintervention, stroke, and cardiovascular-related death.

Update on percutaneous mitral commissurotomy

Percutaneous mitral commissurotomy (PMC) is the first-line therapy for managing rheumatic mitral stenosis. Over the past two decades, the indications of the procedure have expanded to include patients with unfavourable valve anatomy as a consequence of epidemiological changes in patient population. The procedure is increasingly being performed in patients with increased age, more deformed valves and associated comorbidities. Echocardiography plays a crucial role in patient selection and to guide a more efficient procedure. The main echocardiographic predictors of immediate results after PMC are mitral valve area, subvalvular thickening and valve calcification, especially at the commissural level. However, procedural success rate is not only dependent on valve anatomy, but a number of other factors including patient characteristics, interventional management strategies and operator expertise. Severe mitral regurgitation continues to be the most common immediate procedural complication with unchanged incidence rates over time. The long-term outcome after PMC is mainly determined by the immediate procedural results. Postprocedural parameters associated with late adverse events include mitral valve area, mitral regurgitation severity, mean gradient and pulmonary artery pressure. Mitral restenosis is an important predictor of event-free survival rates after successful PMC, and repeat procedure can be considered in cases with commissural refusion. PMC can be performed in special situations, which include high-risk patients, during pregnancy and in the presence of left atrial thrombus, especially in centres with specialised expertise. Therefore, procedural decision-making should take into account the several determinant factors of PMC outcomes. This paper provides an overview and update of PMC techniques, complications, immediate and long-term results over time, and assessment of suitability for the procedure.

Subvalvular apparatus and adverse outcome of balloon valvotomy in rheumatic mitral stenosis

BACKGROUND

Balloon mitral valvotomy (BMV) is a well-established therapeutic modality for rheumatic mitral stenosis (RMS). However, there are chances of procedural failure and the more ominous post-procedural severe mitral regurgitation. There are only a few prospective studies, which have evaluated the pathogenic mechanisms for these major complications of BMV, especially in relation to the subvalvular apparatus (SVA) pathology.

METHODS

All symptomatic patients of RMS suitable for BMV by echocardiographic criteria in a span of 1 year were selected. In addition to the standard echocardiographic assessment of RMS (Wilkins score and score by Padial et al.), a separate grading and scoring system was assigned to evaluate the severity of the SVA pathology. The SVA score was 'I', when none of the two SVAs had severe disease, 'II' when one of the two SVAs has severe disease, and 'III' when both SVAs had severe disease. With these scoring systems, the outcomes of BMV (successful procedure, failure, and post-procedural mitral regurgitation) were analyzed. Emergency valve replacement was performed depending on clinical situation, and in cases of replacement, the pathology of the excised mitral valves were compared with echocardiographic findings.

RESULTS

Of the 356 BMVs performed in a year, 43 patients had adverse outcomes in the form of failed procedure (14 patients) and mitral regurgitation (29 patients). Forty-one among these had a SVA score of III. The sensitivity and specificity of the MR score was lesser than the SVA score (sensitivity 0.34 vs. 1.00, specificity 0.92 vs. 0.99, respectively). The mitral valvular morphology in 39 patients who underwent post-procedural valve replacements correlated well with echocardiography findings.

CONCLUSION

It is important to assess the degree of SVA pathology in the conventional echocardiographic assessment for RMS, as BMV would have adverse events when both SVAs were severely diseased.

The echo score revisited: Impact of incorporating commissural morphology and leaflet displacement to the prediction of outcome for patients undergoing percutaneous mitral valvuloplasty

BACKGROUND

Current echocardiographic scoring systems for percutaneous mitral valvuloplasty (PMV) have limitations. This study examined new, more quantitative methods for assessing valvular involvement and the combination of parameters that best predicts immediate and long-term outcome after PMV.

METHODS AND RESULTS

Two cohorts (derivation n=204 and validation n=121) of patients with symptomatic mitral stenosis undergoing PMV were studied. Mitral valve morphology was assessed by using both the conventional Wilkins qualitative parameters and novel quantitative parameters, including the ratio between the commissural areas and the maximal excursion of the leaflets from the annulus in diastole. Independent predictors of outcome were assigned a points value proportional to their regression coefficients: mitral valve area ≤1 cm(2) (2), maximum leaflets displacement ≤12 mm (3), commissural area ratio ≥1.25 (3), and subvalvular involvement (3). Three risk groups were defined: low (score of 0-3), intermediate (score of 5), and high (score of 6-11) with observed suboptimal PMV results of 16.9%, 56.3%, and 73.8%, respectively. The use of the same scoring system in the validation cohort yielded suboptimal PMV results of 11.8%, 72.7%, and 87.5% in the low-, intermediate-, and high-risk groups, respectively. The model improved risk classification in comparison with the Wilkins score (net reclassification improvement 45.2%; P<0.0001). Long-term outcome was predicted by age and postprocedural variables, including mitral regurgitation, mean gradient, and pulmonary pressure.

CONCLUSIONS

A scoring system incorporating new quantitative echocardiographic parameters more accurately predicts outcome following PMV than existing models. Long-term post-PMV event-free survival was predicted by age, degree of mitral regurgitation, and postprocedural hemodynamic data.