Beating Heart Catheter-Based Edge-to-Edge Mitral Valve Procedure in a Porcine Model

Transcatheter Edge-to-Edge Repair in Valvular Heart Disease: A Comprehensive Exploration of Equipment, Efficacy, Gender, Racial, and Socioeconomic Disparities, and Future Prospects

The 2 primary components of valvular heart disease are mitral regurgitation (MR) and tricuspid regurgitation (TR). Transcatheter edge-to-edge repair (TEER) is an advanced, minimally invasive procedure that has recently displayed encouraging outcomes in the treatment of these pathologies. TEER offers a nonsurgical alternative for individuals diagnosed with conditions deemed to be high-risk surgical candidates. Currently, the TEER procedure employs devices such as MitraCLIP and TriCLIP, as well as innovative PASCAL (transcatheter valve repair system used for mitral and tricuspid valve repair) and FORMA (repair system used for tricuspid valve repair) repair systems. In the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) trial enrolling 614 patients to test the efficacy of TEER in MR, a significant reduction in hospitalization due to heart failure was observed at 24 months in the MitraClip + guideline-directed medical therapy (GDMT) group (35.8%) than in the GDMT-alone group (67.9%), HR, 0.53; P < 0.001, lower rate of all-cause mortality at 29.1% compared with 46.1% (P < 0.001), lower risk of cerebrovascular events (P = 0.001), and lower mortality due to cardiovascular events (P < 0.001). In another trial, patients with moderate TR or greater than New York Heart Association Class II or higher underwent TEER using the TriClip for the management of TR. The outcomes were encouraging, with 86% of patients showing a reduction in TR severity of at least one grade. As the technology and research surrounding TEER continue to progress, a more extensive range of patients are expected to qualify for TEER procedures. Our comprehensive review sought to extensively explore the background, equipment used, effectiveness of MR and TR, potential side effects, future prospects, and ongoing trials associated with TEER. We further discuss the existing gender, racial, and socioeconomic disparities in the realm of TEER.

Transcatheter Treatment Options for Functional Mitral Regurgitation: Which Device for Which Patients?

Mitral regurgitation is the most common valvular disease in the developed world, with approximately 24.2 million people being affected worldwide and a higher prevalence in older age groups. Surgical correction of degenerative mitral regurgitation is the standard of care and can restore cardiac function and provide a lasting result, especially when the mitral valve can be repaired. Secondary mitral regurgitation, or functional mitral regurgitation (FMR), describes atrial or ventricular factors leading to poor coaptation of an otherwise non-diseased valve. For FMR, traditional surgery has not produced the same level of benefit. Transcatheter mitral repair and replacement techniques that mimic surgical correction are under investigation. Transcatheter edge-to-edge repair is the only approved catheter-based therapy for FMR in the US. Here, the transcatheter treatment options for FMR are reviewed.

Machine learning used for simulation of MitraClip intervention: A proof-of-concept study

Introduction: Severe mitral regurgitation (MR) is a mitral valve disease that can lead to lifethreatening complications. MitraClip (MC) therapy is a percutaneous solution for patients who cannot tolerate surgical solutions. In MC therapy, a clip is implanted in the heart to reduce MR. To achieve optimal MC therapy, the cardiologist needs to foresee the outcomes of different scenarios for MC implantation, including the location of the MC. Although finite element (FE) modeling can simulate the outcomes of different MC scenarios, it is not suitable for clinical usage because it requires several hours to complete.

Methods: In this paper, we used machine learning (ML) to predict the outcomes of MC therapy in less than 1 s. Two ML algorithms were used: XGBoost, which is a decision tree model, and a feed-forward deep learning (DL) model. The MC location, the geometrical attributes of the models and baseline stress and MR were the features of the ML models, and the predictions were performed for MR and maximum von Mises stress in the leaflets. The parameters of the ML models were determined to achieve the minimum errors obtained by applying the ML models on the validation set.

Results: The results for the test set (not used during training) showed relative agreement between ML predictions and ground truth FE predictions. The accuracy of the XGBoost models were better than DL models. Mean absolute percentage error (MAPE) for the XGBoost predictions were 0.115 and 0.231, and the MAPE for DL predictions were 0.154 and 0.310, for MR and stress, respectively.

Discussion: The ML models reduced the FE runtime from 6 hours (on average) to less than 1 s. The accuracy of ML models can be increased by increasing the dataset size. The results of this study have important implications for improving the outcomes of MC therapy by providing information about the outcomes of MC implantation in real-time.

Late Infective Endocarditis After Transcatheter Mitral Valve Reconstruction (MitraClip): A Case Report and a Review of the Literature

Percutaneous transcatheter mitral valve reconstruction in edge to edge fashion is a well-established option in inoperable or high peri-operative risk patients with severe, symptomatic mitral valve regurgitation. MitraClip in combination with medical treatment improves survival and reduces hospitalization rates compared with optimal medical therapy alone in well selected patients. Clip-associated endocarditis is a rare complication with only few reported cases in the literature. We present a case of late infective endocarditis post Mitral Clip implantation and also review the literature regarding this new rare condition.

Were they inoperable? Really?

The MitraClip technique has been increasingly used for correction of mitral valve regurgitation in patients in whom surgical mitral repair is considered contraindicated or very risky, but off label use occurs often. Failure of the procedure, translated into moderate to severe rates of residual or recurrent mitral regurgitation, is observed in up to one-third of the patients, and surgery has been used to correct it in a number of cases, in what can be called an "operation for the inoperable." That is precisely the subtitle of a paper published in this issue of the JOCS by Gerfen and colleagues, who analyse their institutional experience with a series of 17 patients. In this Editorial, I comment on this series and the possible reasons for failure of the MitraClip, and on the indications for reintervention and its constraints, which I hope can contribute to the discussion about "further exploration and refinement of patient selection criteria and identify predictors for MitraClip failure," as the authors suggest.

Infective endocarditis - A review of current therapy and future challenges

Etiological, microbiological and epidemiological factors changed over time, but mortality rates remain high in infective endocarditis (IE). Healthcare-associated IE is nowadays responsible for a significant proportion of cases due to increasing numbers of cardiac devices. Cardiac implantable electronic devices, transcatheter aortic valve replacement, and percutaneous valve repair are meanwhile used, especially in old and sick patients. In suspected IE modified Duke criteria, integrating clinical results, imaging, and biomarkers are traditionally applied. Newer imaging technologies such as multi-slice computed tomography, photon-emission computed tomography, and magnetic resonance imaging might add value to conventional echocardiography in diagnosis and management of IE. Treatment consists of long-term antibiotic therapy, infectiological source control and/or cardiac surgery. Recently, antibiotic parenteral outpatient regimens and partial oral treatment strategies were shown to shorten hospital stays in patients suffering from IE. However, it remains unclear how to best select patients for partial oral therapy. This review describes new trends in diagnosing, imaging, and treating IE in a changing patient collective with particular focus on patients with implantable cardiac devices.

Multiple MitraClips: The balancing act between pressure gradient and regurgitation

OBJECTIVE

Transcatheter mitral valve repair with the MitraClip is used for the symptomatic management of mitral regurgitation (MR). The challenge is reducing MR while avoiding an elevated mitral valve gradient (MVG). This study assesses how multiple MitraClips used to treat MR can affect valve performance.

METHODS

Six porcine mitral valves were assessed using an in vitro left heart simulator in the native, moderate-to-severe MR, and severe MR cases. MR cases were tested in the no-MitraClip, 1-MitraClip, and 2-MitraClip configurations. Mitral regurgitant fraction (MRF), MVG, and effective orifice area (EOA) were quantified.

RESULTS

Native MRF, MVG, and EOA were 14.22%, 2.59 mm Hg, and 1.64 cm², respectively. For moderate-to-severe MR, MRF, MVG, and EOA were 34.07%, 3.31 mm Hg, and 2.22 cm², respectively. Compared with the no-MitraClip case, 1 MitraClip decreased MRF to 18.57% (P < .0001) and EOA to 1.50 cm² (P = .0002). MVG remained statistically unchanged (3.44 mm Hg). Two MitraClips decreased MRF to 14.26% (P < .0001) and EOA to 1.36 cm² (P = .0001). MVG remained unchanged (3.29 mm Hg). For severe MR, MRF, MVG, and EOA were 59.79%, 4.98 mm Hg, and 2.73 cm², respectively. Compared with the no-MitraClip case, 1 MitraClip decreased MRF to 30.72% (P < .0001) and EOA to 1.82 cm² (P < .0001); MVG remained unchanged (4.03 mm Hg). MVG remained statistically unchanged. Two MitraClips decreased MRF to 23.10% (P < .0001) and EOA to 1.58 cm² (P < .0001); MVG remained statistically unchanged (3.82 mm Hg). Both MR models yielded no statistical difference between 1 and 2 MitraClips.

CONCLUSIONS

There is limited concern regarding elevation of MVG when reducing MR using 1 or 2 MitraClips, although 2 MitraClips did not significantly continue to reduce MRF.

Advances in transcatheter mitral and tricuspid therapies

BACKGROUND

While rheumatic mitral stenosis has been effectively treated percutaneously for more than 20 years, mitral and tricuspid regurgitation treatment appear as a contemporary unmet need. The advent of transcatheter therapies offer new treatment options to often elderly and frail patients at high risk for open surgery. We aimed at providing an updated review of fast-growing domain of transcatheter mitral and tricuspid technology.

MAIN BODY

We reviewed the existing literature on mitral and tricuspid transcatheter therapies. Mitraclip is becoming an established therapy for secondary mitral regurgitation in selected patients with disproportionately severe regurgitation associated with moderate left ventricle dysfunction. Evidence is less convincing for primary mitral regurgitation. Transcatheter mitral valve replacement is a promising emerging alternative to transcatheter repair, for secondary as well as primary mitral regurgitation. But further development is needed to improve delivery. Transcatheter tricuspid intervention arrives late after similar technologies have been developed for aortic and mitral valves and is currently at its infancy. This is likely due in part to previously under-recognized impact of tricuspid regurgitation on patient outcomes. Edge-to-edge repair is the most advanced transcatheter solution in development. Data on tricuspid annuloplasty and replacement is limited, and more research is warranted.

CONCLUSION

The future appears bright for transcatheter mitral therapies, albeit their place in clinical practice is yet to be clearly defined. Tricuspid transcatheter therapies might address the unmet need of tricuspid regurgitation treatment.

MitraClip in Asia - Current Adoption and Regional Data

In the United States and Europe, percutaneous edge-to-edge repair of the mitral valve with the MitraClip device for patients with severe degenerative mitral regurgitation who are at prohibitive surgical risk has been well-established. Recent randomized controlled trials have also demonstrated significant clinical benefits with the use of the device in selected patients with functional mitral regurgitation. Thus far, >80,000 patients in more than 50 countries have undergone the MitraClip procedure. Despite the exponential growth worldwide, the rate of MitraClip adoption in Asia has been more gradual. In addition, very few publications describe the use of MitraClip in Asian populations. This review aims to describe the Asian experience with the MitraClip device and the challenges faced.

Predictors of adverse outcomes after transcatheter mitral valve replacement

Introduction: Transcatheter mitral valve replacement (TMVR) is still a recent technology with numerous unknowns but also great promises. The risk of complications reported in observational studies have limited its adoption by interventional cardiology and surgical communities. Areas covered: Some of the major setbacks of TMVR are complications related to the devices and those related to the pathway. Device-related complications include left ventricle outflow tract (LVOT) obstruction, transcatheter heart valve (THV) dislocation or embolization, thrombosis, and stroke. The transapical approach currently remains the main pathway for TMVR but is associated with high risk of major bleeding and residual apical myocardial scarring. Complication prediction and prevention seem possible. Device-related complication prediction is based on pre-operative imaging including multi-slice computed tomography with 3-dimensional reconstructions and echocardiography which allow LVOT obstruction prediction and appropriate sizing aiming at avoiding dislocation. Industry should aim at the development of transfemoral delivery systems. Nevertheless, several recent feasibility observational studies suggested acceptable safety and efficacy of transcatheter mitral valve replacement. Expert opinion: TMVR complications and transapical delivery are some of the main setbacks which need to be addressed for TMVR to be adopted for broad clinical use.

Tricuspid Valve Regurgitation Decreases after MitraClip Implantation: Fluid Structure Interaction Simulation

Untreated tricuspid valve regurgitation (TR) is associated with increased rates of mortality, morbidity, and hospitalization. Current pharmacological and surgical treatment options for TR are limited. MitraClip (MC), an edge-to-edge percutaneous intervention, has been reported to be effective for treatment of TR. The goal of this study was to examine the effects of MC position on TR, using a multiphysics fluid-structure-interaction (FSI) analysis. The computational set up included the tricuspid valve (TV), the chordae tendineae, the blood particles, and a tube that surrounded the leaflets and blood particles. The leaflets and chordae were modeled as hyperelastic materials, and blood was modeled using smoothed particle hydrodynamics. FSI analysis was conducted for blood flow through the closed valve for multiple simulations that account for normal, diseased, and treated conditions of the TV. To simulate the diseased TV, a group of chordae between septal and pulmonary leaflets were removed from the normal TV, which produced increased regurgitation. Four MC treated scenarios were considered: i) one MC near the annulus, ii) one MC approximately midway between the annulus and leaflet tip, iii) one MC near the leaflet tip, iv) two MCs: one approximately midway between the annulus and leaflet tip, and one close to the leaflet tip. The TR increased in diseased TV (7.5%) compared to normal TV (2.5%). All MC treated scenarios decreased TR. The MC located near the midway point between the annulus and leaflet tip led to largest decrease in TR (75.2% compared to the untreated condition). The MC located near the leaflet tip was associated with lowest reduction in TR (2.2% compared to the untreated condition). When two MCs were used, reduction in TR was relatively high (68.7%), but TR was not improved compared to the optimal single MC. MC caused high stresses in the vicinity of the clipping area in all conditions; the highest occurred when the MC was near the leaflet tips. Using a quantitative computational approach, we confirm previous clinical reports on the efficacy of MC for treatment of TR. The results of this study could lead to the design of more efficient MC interventions for TR.

The value of three-dimensional color Doppler trans-esophageal echocardiography in predicting the number of MitraClip devices needed during the procedure

Purpose

During MitraClip procedure, one or more clips might be needed to effectively reduce the mitral regurgitation (MR). Three-dimensional vena-contracta (3D-VC) assessed by color Doppler three-dimensional trans-esophageal echocardiography (3D-TEE) was proven to be well correlated with MR severity. However, its role in predicting the number of MitraClip devices needed during the procedure was not fully determined. Aim of this study is to assess the predictive value of 3D-VC area & length in determining the number of clips needed during the procedure.

Methods

3D-TEE with color Doppler was performed in 20 patients ( age: 68.9 ± 2.5 years; 65% males; with functional severe/moderately severe MR) who underwent successful MitraClip procedure (reduction of MR to <2+). Manual tracing and measurement of the 3D-VC area (3D-VCA) as well as the 3D-VC length (3D-VCL) was done. These values were compared between patients who received 1 clip (n = 4) and ≥ 2 clips (n = 16).

Results

Patients who received ≥ 2 clips had larger 3D-VC area compared to patients who received 1 clip (0.39 ± 0.23 cm² vs. 0.13 ± 0.03 cm², p = 0.04, t = 2.22) . Patients who received ≥ 2 clips had bigger 3D-VC length compared to patients who received 1 clip (1.14 ± 0.33 cm vs. p = 0.005, t = 3.25 ). A cut-off values of 0.20 cm² & 1 cm for the VCA & VCL respectively, are suggestive that the patient will most likely require more than one MitraClip device to treat his mitral regurgitation.

Conclusions

The 3D-VCA & 3D-VCA using 3D TEE is helpful indetermining the number of MitraClip devices needed during the procedure in functional mitral regurgitation.

Managing mitral regurgitation: focus on the MitraClip device

Based on the principle of surgical edge-to-edge mitral valve repair (MVR), the MitraClip percutaneous MVR technique has emerged as a minimally invasive option for MVR. This catheter-based system has been widely demonstrated to be safe, although inferior to surgical MVR. Studies examining patients with ≥3+ mitral regurgitation (MR) show that, for all patients treated, freedom from death, surgery, or MR ≥3+ is in the 75%–80% range 1 year following MitraClip implantation. Despite its inferiority to surgical therapy, in high-risk surgical patients, data suggest that the MitraClip system can be employed safely and that it can result in symptomatic improvement in the majority of patients, while not precluding future surgical options. MitraClip therapy also appears to reduce heart failure readmissions in the high-risk cohort, which may lead to an economic benefit. Ongoing study is needed to clarify the impact of percutaneous mitral valve clipping on long-term survival in high-risk populations, as well as its role in other patient populations, such as those with functional MR.

Percutaneous Mitral Valve Edge-to-Edge Repair for Degenerative Mitral Regurgitation

OPINION STATEMENT

Surgical mitral valve (MV) repair remains the gold standard to treat patients with significant degenerative mitral regurgitation (DMR). Medical therapy was the only option for patients found to be not appropriate for MV surgery until the development of percutaneous/transcatheter MV repair options that now allow to reduce MR less invasively and safely. This article discusses the basic mechanisms of MR and the rationale for MR intervention and offers a detailed review on percutaneous/transcatheter MV repair with the MitraClip.

Percutaneous treatment of mitral regurgitation with MitraClip device

The percutaneous edge-to-edge repair of mitral regurgitation with a MitraClip device has been recently approved in Europe. The results of the randomized EVEREST II study showed a favourable safety profile of the technique. However, the efficacy in terms of regurgitation reduction in a population with predominantly degenerative mitral disease was inferior as compared to the results of conventional open heart surgery. Nevertheless, up to 50% of symptomatic heart failure patients with severe mainly functional mitral regurgitation are not treated surgically because of very high procedural risk. The registry data suggest that the minimally invasive and generally well-tolerated MitraClip procedure reduces symptoms and need for recurrent hospitalization and improves left ventricular function in inoperable subjects. The ongoing randomized clinical trials with clinical endpoints will further define the current role of percutaneous edge-to-edge repair in heart failure patients with mitral regurgitation.

Using imaging to guide patient selection and performance of catheter-based mitral valve repair for mitral regurgitation

Percutaneous transcatheter therapies for mitral regurgitation have found a role for patients at high operative risk with both degenerative and functional pathologies. The MitraClip therapy utilizes a catheter-based system to deliver a clip-type implant to provide apposition between anterior and posterior mitral leaflets. Key to the procedure is using imaging to guide patient selection as well as intra-procedure performance. Careful patient selection remains paramount for success with the MitraClip, with imaging determination of appropriate mitral pathology. Technical success is dependent on skill with echocardiographic imaging, with three-dimensional transesophageal echocardiography particularly valuable.

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.

Percutaneous Treatment of Mitral Regurgitation: The MitraClip Experience

The MitraClip device is a percutaneous catheter-delivered, implantable clip that reduces mitral regurgitation by approximating the edges of the mitral leaflets, creating an "edge-to-edge" repair. The MitraClip is the first percutaneous technology developed to provide a minimally invasive option for patients at high risk for traditional mitral valve surgery. Although percutaneous repair was less effective at reducing mitral regurgitation than conventional surgery in the EVEREST randomized trial, the procedure was associated with superior safety and similar improvements in clinical outcomes. Older, high-risk or inoperable patients with functional or degenerative mitral regurgitation seem to benefit most from this therapy.

Percutaneous repair or surgery for mitral regurgitation

BACKGROUND

Mitral-valve repair can be accomplished with an investigational procedure that involves the percutaneous implantation of a clip that grasps and approximates the edges of the mitral leaflets at the origin of the regurgitant jet.

METHODS

We randomly assigned 279 patients with moderately severe or severe (grade 3+ or 4+) mitral regurgitation in a 2:1 ratio to undergo either percutaneous repair or conventional surgery for repair or replacement of the mitral valve. The primary composite end point for efficacy was freedom from death, from surgery for mitral-valve dysfunction, and from grade 3+ or 4+ mitral regurgitation at 12 months. The primary safety end point was a composite of major adverse events within 30 days.

RESULTS

At 12 months, the rates of the primary end point for efficacy were 55% in the percutaneous-repair group and 73% in the surgery group (P=0.007). The respective rates of the components of the primary end point were as follows: death, 6% in each group; surgery for mitral-valve dysfunction, 20% versus 2%; and grade 3+ or 4+ mitral regurgitation, 21% versus 20%. Major adverse events occurred in 15% of patients in the percutaneous-repair group and 48% of patients in the surgery group at 30 days (P<0.001). At 12 months, both groups had improved left ventricular size, New York Heart Association functional class, and quality-of-life measures, as compared with baseline.

CONCLUSIONS

Although percutaneous repair was less effective at reducing mitral regurgitation than conventional surgery, the procedure was associated with superior safety and similar improvements in clinical outcomes. (Funded by Abbott Vascular; EVEREST II ClinicalTrials.gov number, NCT00209274.).

Percutaneous mitral valve repair using the edge-to-edge technique in a high-risk population

Background. Percutaneous mitral valve (MV) repair using the edge-to-edge clip technique might be an alternative for patients with significant mitral regurgitation (MR) and an unacceptably high risk for operative repair or replacement. We report the short-term safety and efficacy of this new technique in a high-risk population.Methods. All consecutive high-risk patients who underwent percutaneous MV repair with the Mitraclip(®) between January and August 2009 were included. All complications related to the procedure were reported. Transthoracic echocardiography for MR grading and right ventricular systolic pressure (RVSP) measurement were performed before, and at three and 30 days after the procedure. Differences in NYHA functional class and quality of life (QoL) index were reported. Results. Nine patients were enrolled (78% male, age 75.9±9.0 years, logistic EuroSCORE 33.8±9.0%). One patient developed inguinal bleeding. In one patient partial clip detachment occurred, a second clip was placed successfully. The MR grade before repair was ≥3 in 100%, one month after repair a reduction in MR grade to ≤2 was present in 78% (p=0.001). RVSP decreased from 43.9±12.1 to 31.6±11.7 mmHg (p=0.009), NYHA functional class improved from median 3 (range 3 to 4) to 2 (range 1 to 4) (p=0.04), and QoL index improved from 62.9±16.3 to 49.9±30.7 (p=0.12). Conclusion. In high-risk patients, transcatheter MV repair seems to be safe and a reduction in MR can be achieved in most patients, resulting in a short-term improvement of functional capacity and QoL. (Neth Heart J 2010;18:437-43.).

Emerging approaches of transcatheter valve repair/insertion

Aortic stenosis (AS) and mitral regurgitation (MR) account for the majority of valvular diseases and their prevalence is increasing according to increased life expectancy. Surgical treatment is the gold standard, although operative risk may be high in some patients due to comorbidities and age. A large part of the patients at high surgical risk who could beneficiate of treatment are not referred to surgery. Therefore, there is a need of alternative and less invasive procedures.

Need for new materials, biofunctionalization and non-surgical heart valve technology

Transition from non-surgical heart valve defects repair from bench to bedside is a reality. Some biological material-based designs for transcatheter aortic valve implantation are ready for use. Their drawback, however is their unknown functional as well as structural durability. Moreover, research on new non-biological materials is essential to replace classical animal-derived sources of human heart valve prostheses.

Percutaneous mitral valve repair with the edge-to-edge technique

Percutaneous treatment of mitral valve regurgitation with the MitraClip™ system is emerging as an alternative to surgery in high-risk and inoperable patients. The device is designed to bond the opposing leaflets at the site of regurgitation, reproducing the results of the Alfieri technique in a beating heart approach. We describe the selection criteria and the procedural steps of the procedure, which is performed under general anesthesia and guided by trans-esophageal echocardiography, using a sophisticated delivery system to deliver the clip at the desired target. We also briefly report the currently available data which supports the application of this therapy in selected patients with either degenerative or functional mitral regurgitation.

Mitral cerclage annuloplasty, a novel transcatheter treatment for secondary mitral valve regurgitation: initial results in swine

OBJECTIVES

We developed and tested a novel transcatheter circumferential annuloplasty technique to reduce mitral regurgitation in porcine ischemic cardiomyopathy.

BACKGROUND

Catheter-based annuloplasty for secondary mitral regurgitation exploits the proximity of the coronary sinus to the mitral annulus, but is limited by anatomic variants and coronary artery entrapment.

METHODS

The procedure, "cerclage annuloplasty," is guided by magnetic resonance imaging (MRI) roadmaps fused with live X-ray. A coronary sinus guidewire traverses a short segment of the basal septal myocardium to re-enter the right heart where it is exchanged for a suture. Tension is applied interactively during imaging and secured with a locking device.

RESULTS

We found 2 feasible suture pathways from the great cardiac vein across the interventricular septum to create cerclage. Right ventricular septal re-entry required shorter fluoroscopy times than right atrial re-entry, which entailed a longer intramyocardial traversal but did not cross the tricuspid valve. Graded tension progressively reduced septal-lateral annular diameter, but not end-systolic elastance or regional myocardial function. A simple arch-like device protected entrapped coronary arteries from compression even during supratherapeutic tension. Cerclage reduced mitral regurgitation fraction (from 22.8 +/- 12.7% to 7.2 +/- 4.4%, p = 0.04) by slice tracking velocity-encoded MRI. Flexible cerclage reduced annular size but preserved annular motion. Cerclage also displaced the posterior annulus toward the papillary muscles. Cerclage introduced reciprocal constraint to the left ventricular outflow tract and mitral annulus that enhanced leaflet coaptation. A sample of human coronary venograms and computed tomography angiograms suggested that most have suitable venous anatomy for cerclage.

CONCLUSIONS

Transcatheter mitral cerclage annuloplasty acutely reduces mitral regurgitation in porcine ischemic cardiomyopathy. Entrapped coronary arteries can be protected. MRI provided insight into the mechanism of cerclage action.

Percutaneous valve procedures: Present and future

Percutaneous mitral commissurotomy and aortic valvuloplasty have been being performed since the mid-1980s. Balloon commissurotomy has been used in thousands of cases worldwide and it provides good short- and long-term results in a wide range of patients. It has virtually replaced surgical commissurotomy in the treatment of mitral stenosis. In contrast, percutaneous aortic valvuloplasty is almost abandoned worldwide due to its lack of efficacy and the risks involved. The new techniques of percutaneous valve intervention: aortic valve replacement and mitral valve repair are at an early stage: the first in-man applications of these fledgling techniques started in 2002. Preliminary series show that they are feasible; however, they need to be further evaluated in comparison with contemporary treatment to assess accurately how efficient they are and the risks involved. Currently potential applications concern high-risk patients, however, in the future, after thorough evaluation, this may be extended to others. Thus, percutaneous interventions already play an important role in treatment of valvular heart disease, a role that seems set for future expansion.

Echocardiography-guided interventions

A major advantage of echocardiography over other advanced imaging modalities (magnetic resonance imaging, computed tomographic angiography) is that echocardiography is mobile and real time. Echocardiograms can be recorded at the bedside, in the cardiac catheterization laboratory, in the cardiovascular intensive care unit, in the emergency room-indeed, any place that can accommodate a wheeled cart. This tremendous advantage allows for the performance of imaging immediately before, during, and after various procedures involving interventions. The purpose of this report is to review the use of echocardiography to guide interventions. We provide information on the selection of patients for interventions, monitoring during the performance of interventions, and assessing the effects of interventions after their completion. In this document, we address the use of echocardiography in commonly performed procedures: transatrial septal catheterization, pericardiocentesis, myocardial biopsy, percutaneous transvenous balloon valvuloplasty, catheter closure of atrial septal defects (ASDs) and patent foramen ovale (PFO), alcohol septal ablation for hypertrophic cardiomyopathy, and cardiac electrophysiology. A concluding section addresses interventions that are presently investigational but are likely to enter the realm of practice in the very near future: complex mitral valve repairs, left atrial appendage (LAA) occlusion devices, 3-dimensional (3D) echocardiographic guidance, and percutaneous aortic valve replacement. The use of echocardiography to select and guide cardiac resynchronization therapy has recently been addressed in a separate document published by the American Society of Echocardiography and is not further discussed in this document. The use of imaging techniques to guide even well-established procedures enhances the efficiency and safety of these procedures.

Surgical repair of the mitral valve in children with dilated cardiomyopathy and mitral regurgitation

BACKGROUND

Significant mitral regurgitation is known to exacerbate left ventricular dysfunction in dilated cardiomyopathy. Although intervention on the regurgitant mitral valve is frequently described in adults, there is little pediatric data.

METHODS

Five children (aged 3 months to 4 years) with dilated cardiomyopathy and mitral regurgitation underwent mitral valve repair between January 1999 and January 2007 at our institution. All had mitral regurgitation graded as moderate to severe, with ejection fractions of 35% to 60% (median 53%).

RESULTS

There were no deaths; all children were weaned from cardiopulmonary bypass; 1 child required cardiac transplantation 3 weeks after repair. After surgery, mitral regurgitation was moderate in 1 patient, mild in 2 patients, and trivial in 2 patients. The 4 successful cases showed an improvement in functional status at latest follow-up (range, 8 years to 4 months): all were asymptomatic (4 children had preoperative symptoms). Successful cases showed a decreased left atrial dimension (mean z-score 3.8 to 2.6) and a decreased left ventricular end-diastolic diameter (mean 6.9 +/- 1.6 to 5.4 +/- 1.2). Ejection fraction and left ventricular end-systolic index did not show an improvement and declined in some cases.

CONCLUSIONS

We conclude that repair of the mitral valve is feasible in children with dilated cardiomyopathy and acquired mitral regurgitation. Most of the children demonstrated decreased left ventricular chamber sizes and an improved functional status. Although this operation improves symptoms, it is not clear whether it postpones or abrogates the need for cardiac transplantation.