Transesophageal echocardiographic evaluation of mitral valve morphology to predict outcome after balloon mitral valvotomy

Percutaneous Mitral Valve Interventions

Percutaneous interventions for mitral valve disease represent both the oldest and the newest of catheter interventions. Balloon mitral valvuloplasty was among the first effective catheter therapies for valvular heart disease. The technique and device approach was initially reported by Inoue in 1982 and, remarkably, is virtually unchanged between then and now. Conversely, novel catheter therapies to repair mitral regurgitation are now in their infancy, with only the earliest human experience. This article details the spectrum of these therapies.

Advances in 3D echocardiography for mitral valve

The advent of real-time (RT) 3D transesophageal echocardiography (TEE) in 2007 has enhanced our understanding of the location and extent of the pathology of the native, as well as prosthetic, mitral valve (MV), particularly for MV prolapse and the anatomy of perivalvular dehiscence with prosthetic MV. MV quantification programs provide precise assessment of many quantitative MV parameters allowing 3D echocardiography to determine and quantify the geometry of mitral apparatus, including mitral annulus and periannular region, leaflet volume and anatomy, tethering distances, and tenting volumes. The detailed, accurate and optimal RT spatial visualization of the MV with 3D TEE gives greater confidence to the echocardiographer, interventionalist and the surgeon alike, facilitating medical and surgical treatment decisions. This article highlights recent advances in RT 3D TEE and transthoracic echocardiography echocardiographic imaging of the MV.

Intracardiac echocardiography: clinical utility and application

Intracardiac echocardiography (ICE) broadens the spectrum of available echocardiographic techniques and provides the operator direct visualization of cardiac structures in real time. ICE has clear advantages over fluoroscopy, transthoracic echocardiography, and transesophageal echocardiography as the imaging modality of choice in the cardiac catheterization and electrophysiological laboratories. With the development of steerable phased array catheters with low frequency and Doppler qualities, there is marked improvement in visualization of left-sided structures from the right heart. Appropriate utilization of ICE is likely to maximize safety and efficacy of complex interventional procedures and may improve patient outcomes. Future advances in ICE imaging will further improve the ease of device guidance and, in combination with new imaging modalities, could dramatically improve other applications of echocardiography which may result in improved patient outcomes. This review describes the technical evolution of ICE, the use of ICE in guiding percutaneous interventional procedures and possible future applications of ICE in the ever-growing field of interventional cardiology.

Repeat percutaneous balloon mitral valvotomy vs. mitral valve replacement in patients with restenosis after previous balloon mitral valvotomy and unfavorable valve characteristics

BACKGROUND

Symptomatic mitral restenosis develops in up to 21% of patients after percutaneous balloon mitral valvotomy (PBMV), and most of these patients undergo mitral valve replacement (MVR).

HYPOTHESIS

Repeating PBMV (re-PBMV) might be an effective and less-invasive treatment for these patients.

METHODS

Forty-seven patients with post-PBMV mitral restenosis and unfavorable valve characteristics were assigned either to re-PBMV (25 cases; mean age 40.7 ± 11 y, 76% female) or MVR (22 cases; mean age 47 ± 10 y, 69% female) at 51 ± 33 months after the prior PBMV. The mean follow-up was 41 ± 32 months and 63 ± 30 months for the re-PBMV and MVR groups, respectively.

RESULTS

The 2 groups were homogenous in preoperative variables such as gender, echocardiographic findings, and valve characteristics. Patients in the MVR group were older, with a higher mean New York Heart Association functional class, mean mitral valve area, mitral regurgitation grade, and right ventricular systolic pressure (P = 0.03), and more commonly were in AF. There were 3 in-hospital deaths (all in the MVR group) and 4 during follow-up (3 in the MVR group and 1 in the re-PBMV group). Ten-year survival was significantly higher in re-PBMV vs MVR (96% vs. 72.7%, P<0.05), but event-free survival was similar (52% vs. 50%, P = 1.0) due to high reintervention in the re-PBMV group (48% vs. 18.1%, P = 0.02).

CONCLUSIONS

In a population with predominantly unfavorable characteristics for PBMV, short- and long-term outcomes are both reasonable after re-PBMV with less mortality but requiring more reinterventions compared with MVR.

Validation of a new score for the assessment of mitral stenosis using real-time three-dimensional echocardiography

BACKGROUND

The aim of this study was to validate a new real-time three-dimensional echocardiography (RT3DE) score for evaluating patients with mitral stenosis (MS).

METHODS

A two-staged study was conducted. In the first stage, the feasibility of a new RT3DE score was assessed in 17 patients with MS. The second stage was planned to validate the RT3DE score in 74 consecutive patients undergoing percutaneous mitral valvuloplasty. The new RT3DE score was constructed by dividing each mitral valve (MV) leaflet into 3 scallops and was composed of 31 points (indicating increasing abnormality), including 6 points for thickness, 6 for mobility, 10 for calcification, and 9 for subvalvular apparatus involvement. The total RT3DE score was calculated and defined as mild (<8), moderate (8-13), or severe (>or=14). MV morphology was assessed using Wilkins's score and compared with the new RT3DE score.

RESULTS

In the first stage, the RT3DE score was feasible and easily applied to all patients, with good interobserver and intraobserver agreement. In the second stage, RT3DE improved MV morphologic assessment, particularly for the detection of calcification and commissural splitting. Both scores were correlated for assessment of thickness and calcification (r = 0.63, P < .0001, and r = 0.44, P < .0001, respectively). Predictors of optimal percutaneous mitral valvuloplasty success by Wilkins's score were leaflet calcification and subvalvular apparatus involvement, and those by RT3DE score were leaflet mobility and subvalvular apparatus involvement. The incidence and severity of mitral regurgitation were associated with high-calcification RT3DE score.

CONCLUSION

The new RT3DE score is feasible and highly reproducible for the assessment of MV morphology in patients with MS. It can provide incremental prognostic information in addition to Wilkins's score.

Echocardiographic assessment of mitral valve morphology after Percutaneous Transvenous Mitral Commissurotomy (PTMC)

AIMS

PTMC produces significant changes in mitral valve morphology as improvement in leaflets mobility. The determinants of such improvement have not been assessed before.

METHODS AND RESULTS

The study included 291 symptomatic patients with mitral stenosis undergoing PTMC. Post-PTMC subvalvular splitting area was a determinant of post-PTMC excursion in both the anterior (B 0.16, 95% CI 0.03 to 0.30, p < 0.05) and the posterior (B 0.12, 95% CI 0.01 to 0.24, p < 0.05) leaflets. Another determinant was the post-PTMC transmitral pressure gradient for anterior (B -0.02, 95% CI -0.04 to -0.005, p < 0.01) and posterior (B -0.01, 95% CI -0.04 to -0.005, p < 0.05) leaflets excursion. The relationship between post-PTMC MVA and leaflet excursion was non-linear "S curve". There was a steep increase of both anterior (p, 0.02) and posterior (p, 0.03) leaflets excursion with increased MVA till the MVA reached a value of about 1.5 cm2; after which both linear and S curves became nearly parallel.

CONCLUSION

The improvement in leaflets excursion after PTMC is determined by several morphologic and hemodynamic changes produced in the valve. The increase in MVA improves mobility within limit; after which any further increase in MVA is not associated by a significant improvement in mobility in both leaflets.

Feasibility, safety, and morphologic predictors of outcome of repeat percutaneous balloon mitral commissurotomy

Early and mid-term results of repeat percutaneous balloon mitral commissurotomy (PBMC) were analyzed in 35 patients with symptomatic valvular restenosis: 12 patients (34%) after first successful PBMC and 23 patients (66%) after successful surgical closed mitral commissurotomy. Twenty-one patients had bilateral fused commissures, and 14 patients had unilateral or bilateral split commissures. Mitral valve area gain was significantly greater in the group with fused commissures compared with the group with split commissures (0.6 +/- 0.2 vs 0.3 +/- 0.2 cm(2), respectively, p = 0.04).

Initial clinical experience with intracardiac echocardiography in guiding balloon mitral valvuloplasty: technique, safety, utility, and limitations

The objective of this study was to examine the feasibility and technique of intracardiac echocardiography during percutaneous balloon mitral valvuloplasty. Echocardiographic imaging is commonly used during mitral valvuloplasty. Intracardiac echocardiography is a newer technology that may provide superior imaging during complex valvular interventions. Intracardiac echocardiography and transthoracic echocardiography were performed in 19 patients undergoing percutaneous balloon mitral valvuloplasty. Intracardiac ultrasound images were obtained via the femoral vein in all patients. Imaging projections and catheter locations that were useful for the performance of mitral valvuloplasty were defined. Intracardiac echocardiography guided transseptal puncture, augmented the assessment of valve apparatus deformity, facilitated balloon positioning across the mitral valve, and permitted postprocedural valvular assessment including identification of mitral regurgitation with color Doppler. Intracardiac echocardiography provided essential imaging guidance and procedural monitoring during percutaneous mitral valvuloplasty.

The Subvalvular Apparatus in Rheumatic Mitral Stenosis *

The assessment of the structure and function of the subvalvular apparatus (SVA) in patients with rheumatic mitral stenosis (MS) is complex, yet is of major importance prior to therapeutic decision making. Currently available methods of assessment are neither sufficiently accurate nor feasible. We review anatomic and functional aspects of the SVA and define SVA involvement in rheumatic MS. The role of various noninvasive and invasive methods for evaluating the integrity and function of SVA in rheumatic MS, as well as clinical implications and pitfalls in assessment of SVA are also discussed.

Echocardiographic Criteria in Selection of Patients for Percutaneous Mitral Commissurotomy

The purpose of this report is to review the role of echocardiography in the selection of patients for percutaneous mitral commissurotomy (PMC). Echocardiography has become the standard for the assessment of the severity of mitral stenosis and of its consequences. PMC is usually performed only in patients with a valve area of < 1.5 cm(2), whereas pulmonary hypertension or spontaneous echo contrast in the left atrium may lead to intervention in patients with few symptoms. The next step of the echocardiographic evaluation is to eliminate contraindications: left atrial thrombosis (by the systematic performance of a transesophageal examination before PMC), mitral regurgitation >/= 2/4, severe aortic valve disease, mixed tricuspid valve disease, and massive or bicommissural calcification. Finally, echocardiography allows the classification of patients into different anatomic groups for prognostic consideration. There is controversy regarding the best echo score system in the prediction of the results of PMC. Scores using a global evaluation of the valve anatomy are the most widely used, whereas more recently, scores taking into account the uneven distribution of the disease have had promising preliminary results. Overall, echo scores are useful criteria for selecting candidates for PMC, but they should be considered together with the other clinical and procedural variables. Thus, echocardiography has an important role in the selection of patients for PMC, as well as for the guidance of the procedure, the evaluation of the results, and surveillance.

Influence of sub valvular pathology on immediate results and follow up events of Inoue balloon mitral valvotomy

We evaluated the influence of sub valvular pathology (SVP) on the immediate results and follow up events of Inoue Balloon Mitral Valvotomy (IBMY) in 206 patients with severe SVP (Group I) and compared their outcome with 206 age and sex matched patients selected from the rest of 619 patients having mild/moderate SVP (Group II). Pre-procedure echocardiographic recordings were reviewed and mitral valve morphology was evaluated using U.S. California Score. The severe SVP group had lower mitral valve areas (MVA) (0.7 cm2 vs. 0.8 cm2) and higher mean pulmonary artery pressure (MPAP) (46.3+/-16.9 mmHg vs. 40.7+/-16.25 mmHg) and mean pulmonary capillary wedge pressure (PCWP) (27.5+/-7.3 mmHg vs. 25.7+/-8.0 mmHg) (p<0.001). IBMV was done using standard technique. The procedure was technically successful in 192/206 patients (93.2%) in group I and 187/206 (91%) in group II (p=ns). The mean transmitral gradient decreased from 24.8+/-7.6 mmHg to 7.46+/-3.4 mmHg while mean PCWP fell from 27.5+/-7.3 mmHg to 12.2+/-5.6 mmHg and MPAP fell from 46.3+/-16.9 mmHg to 23.6+/-12.2 mmHg (p=<0.001). MVA increased from 0.7+/-0.2 cm2 to 1.7+/-0.4 cm2 (p=<0.001). Severe mitral regurgitation (MR) occurred in 2 patients out of which one patient, who had associated coronary artery disease, died post operatively, and moderate MR occurred in 8 patients. The results achieved in patients with severe SVP were not statistically different from those with mild/moderate SVP. The benefits achieved immediate post IBMV were sustained in 184 patients with severe SVP who were available for follow up at a mean duration of 15.2 months (range 3 months to 51 months). Thus IBMV is safe and effective in patients with severe SVP. This group of patients with severe SVP are more hemodynamically deranged pre-BMV and also achieve better hemodynamic benefit compared to those with mild/moderate SVP. Severe SVP does not have any adverse effect either on immediate results (success/occurrence of MR) or on intermediate term follow up.

Pitfalls and tips in inoue balloon mitral commissurotomy

Balloon mitral commissurotomy is a safe and effective alternative therapeutic modality in selected patients with significant rheumatic mitral stenosis. Since its introduction in 1984, Inoue balloon mitral commissurotomy has gained wider acceptance over other balloon valvuloplasty techniques because it is technically less demanding and associated with fewer complications. Nevertheless, certain pitfalls which may make the procedure more difficult or create complications are sometimes encountered. In this article, we offer tips to facilitate a safe and expeditious execution of Inoue balloon mitral commissurotomy based on our experience with over 1,000 procedures.

Balloon impasse: a marker for severe mitral subvalvular disease and a predictor of mitral regurgitation in Inoue-balloon percutaneous transvenous mitral commissurotomy

In certain instances of percutaneous transvenous mitral commissurotomy, the Inoue catheter balloon, although deflated and properly aligned, becomes held up or checked at the mitral valve. This "balloon impasse," observed in 13 of 760 patients undergoing the commissurotomy, reflects severe obstructive subvalvular disease even though echocardiographic evidence suggests otherwise. Our experience shows that the sign portends severe mitral regurgitation if the usual balloon sizing method is used. Such a situation occurred with four of the first six patients. In the next seven patients, the use of smaller balloon catheters (PTMC-18 or PTMC-20) for the initial set of stepwise dilatations averted creation of severe mitral regurgitation. When the "balloon impasse" sign is encountered during the commissurotomy procedure, the catheter selection and balloon sizing method should be judiciously altered.

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.