Percutaneous tricuspid valve therapies: the new frontier.

Moderate-to-severe tricuspid regurgitation (TR) affects ∼1.6 million patients in the USA, of whom only 8000 undergo tricuspid surgery annually; this results in an extremely large number of untreated patients with significant TR. Therefore, there is a large unmet clinical need for patients with severe TR who are not referred for conventional surgery, mainly due to expected high surgical risk. Percutaneous procedures are an attractive alternative to surgery for patients deemed to be high-risk surgical candidates. Whereas over the past few years, the development and clinical use of percutaneous approaches to the aortic valve and mitral valve have been widespread, few data are available about the feasibility and the efficacy of the percutaneous tricuspid valve treatment. This review will explore the available technologies, which are today under evaluation and the preliminary clinical results.

Transcatheter mitral repair and replacement: state of the art and future directions.

Many patients affected by severe mitral regurgitation (MR) do not currently undergo surgery, mainly because of the high surgical risk due to old age, impaired left ventricular function and comorbidities. Consequently, many transcatheter devices are emerging with the purpose of treating MR in a less-invasive fashion, using different approaches and addressing different anatomic targets. The most widely used device in the clinical setting at present is the MitraClip system (Abbott Vascular, Inc., Menlo Park, CA, USA), which 'clips' the mitral leaflets together to force coaptation, and has shown optimal safety and acceptable clinical results, despite the high-risk profile of the patients in which it is commonly used. Other repair technologies include percutaneous neochordae implantation, direct and indirect annuloplasty, and reshaping of the left ventricle, but these are still undergoing limited clinical trials or preclinical experience. The combination of different repair techniques is likely to be required to achieve good long-lasting results. Transcatheter mitral valve implantation is also under development, and has already been carried out successfully in the context of valve-in-valve, whereas in the native scenario it remains an open challenge because of the particular anatomic and physiologic features of the mitral complex; hence, various prostheses using different concepts are emerging, and the first human cases have already been treated. Because data on the safety, efficacy and durability of all transcatheter mitral therapies are still limited, they are currently reserved to high-risk and inoperable patients, and their application requires an integrated Heart-Team approach. However, they represent the natural evolution of surgery and promise to expand treatment options and improve patient outcomes in the near future.

Simulation of functional tricuspid regurgitation using an isolated porcine heart model.

BACKGROUND AND AIM OF THE STUDY: The results of tricuspid annuloplasty to treat functional tricuspid regurgitation (FTR) are sometimes suboptimal, and alternative techniques are needed. In the absence of reliable FTR models, and in an effort to minimize the need for animal experiments, a reproducible bench-model was developed of FTR, that allowed the simulation of the anatomic features of the condition. METHODS: A fresh porcine heart was mounted on a rigid support that was placed into a basin filled with saline; a closed circuit was then created with a centrifugal pump, equipped with connection tubes. The inflow tube of the pump conveyed saline from the basin to the pump; the outflow cannula was inserted through the pulmonary artery, across the pulmonary valve, into the right ventricle. The pump was activated to pressurize the right ventricle, thus inducing tricuspid valve regurgitation (TVR). The regurgitant flow through the valve was quantified using a flow-meter. Radiopaque markers were sutured to the head of each papillary muscle and to the tricuspid annulus, in order to trace the geometric changes of the tricuspid valve at increasing pump rates, using fluoroscopy. The efficacy of the bench-model was validated with 10 hearts. RESULTS: The TVR was increased proportionally with the right ventricular pressure (RVP) (TVR = 0.089xRVP - 1.515; R2 = 0.89). The increase in TVR was associated with increases in the annular-to-papillary muscles distance (APML) (TVR = 0.059xAPML - 2.94; R2 = 0.96), of the inter-papillary muscles distance (PMD) (TVR = 0.058xPMD - 8.58; R2 = 0.94), and of the triscuspid annular dilatation (TAD) (TVR = 0.05xTAD - 1.85; R2 = 0.89). Of these parameters, APML was the strongest predictor of TVR. CONCLUSION: The porcine heart bench model represents a reproducible system to simulate the physiopathology of FTR, and has the potential to serve as a complementary method for the evaluation of new 'in vitro' technologies and therapies for FTR.

Corrigendum to: Management of Tricuspid Regurgitation: The Role of Transcatheter Therapies.

[This corrects the article DOI: 10.15420/icr.2017:3:2.].

Reintroducing Heart Sounds for Early Detection of Acute Myocardial Ischemia in a Porcine Model - Correlation of Acoustic Cardiography With Gold Standard of Pressure-Volume Analysis.

BACKGROUND: Acoustic cardiography is a hybrid technique that couples heart sounds recording with ECG providing insights into electrical-mechanical activity of the heart in an unsupervised, non-invasive and inexpensive manner. During myocardial ischemia hemodynamic abnormalities appear in the first minutes and we hypothesize a putative diagnostic role of acoustic cardiography for prompt detection of cardiac dysfunction for future patient management improvement. METHODS AND RESULTS: Ten female Swiss large white pigs underwent permanent distal coronary occlusion as a model of acute myocardial ischemia. Acoustic cardiography analyses were performed prior, during and after coronary occlusion. Pressure-volume analysis was conducted in parallel as an invasive method of hemodynamic assessment for comparison. Similar systolic and diastolic intervals obtained with the two techniques were significantly correlated [Q to min dP/dt vs. Q to second heart sound (r 2 = 0.9583, p < 0.0001), PV diastolic filling time vs. AC perfusion time (r 2 = 0.9686, p < 0.0001)]. Indexes of systolic and diastolic impairment correlated with quantifiable features of heart sounds [Tau vs. fourth heart sound Display Value (r 2 = 0.2721, p < 0.0001) cardiac output vs. third heart sound Display Value (r 2 = 0.0791 p = 0.0023)]. Additionally, acoustic cardiography diastolic time (AUC 0.675, p = 0.008), perfusion time (AUC 0.649, p = 0.024) and third heart sound Display Value (AUC 0.654, p = 0.019) emerged as possible indicators of coronary occlusion. Finally, these three parameters, when joined with heart rate into a composite joint-index, represent the best model in our experience for ischemia detection (AUC 0.770, p < 0.001). CONCLUSION: In the rapidly evolving setting of acute myocardial ischemia, acoustic cardiography provided meaningful insights of mechanical dysfunction in a prompt and non-invasive manner. These findings should propel interest in resurrecting this technique for future translational studies as well as reconsidering its reintroduction in the clinical setting.

Transcatheter aortic valve-in-ring implantation: feasibility in an acute, preclinical, pilot trial.

OBJECTIVES: The HAART ring device has been introduced as a novel strategy to facilitate aortic valve repair. This rigid, elliptical device aims to restore normal leaflet configuration and to provide annular stabilization in the setting of aortic regurgitation. The goal of this preclinical study is to evaluate the in vivo feasibility of 'aortic valve-in-ring' transcatheter aortic valve replacement (TAVR). METHODS: Six animals {landrace pigs, 87.6 [standard deviation (SD) 4.5] kg} underwent HAART ring implantation (5 cases #19 mm and 1 case #21 mm) via full sternotomy with cardiopulmonary bypass. Seven transfemoral TAVR implantations were performed with the Medtronic EvolutR prosthesis to assess the sizing and outcome (5 cases #23 mm, 1 case #26 mm and 1 case #29 mm). RESULTS: TAVR implantation was successful in 6 of 7 attempts. Post-dilatation was performed in 1 case without damage of the ring or the valve. One embolization occurred due to oversizing (EvolutR valve 29 mm in HAART ring 19 mm). No clinically relevant postimplantation gradient [7.6 (SD 4.0) mmHg] or regurgitation was detected by invasive and echocardiographic measurements. Postoperative computed tomography scans revealed good device configuration. CONCLUSIONS: Transcatheter aortic valve-in-ring implantation of a self-expandable TAVR into a rigid aortic annuloplasty ring after aortic valve repair appears feasible. Proper sizing and correct depth of implantation are crucial.

Echocardiographic-fluoroscopic fusion imaging for transcatheter mitral valve repair guidance.

The echocardiographic-fluoroscopic fusion imaging is a new imaging system which has recently become available, with the proposal to facilitate catheters and device navigation during catheter-based structural heart disease interventions. Several reports have described the early developments and the first clinical experiences, but literature focusing on the practical applications of fusion imaging technology to mitral valve transcatheter interventions, and on its potential advantages and current limitations, is still limited. In this review, we, therefore, describe the role of this novel imaging system during Mitraclip, Cardioband, and paravalvular leak closure interventions. The technical principles and the fluoroscopic anatomy of the interatrial septum and mitral valve are also described.

Evaluation of Valtech's transcatheter mitral valve repair device.

INTRODUCTION: Functional mitral regurgitation is a debilitating condition, related to worsening of functional capacity and heart failure symptomatology. Cardioband (Valtech Cardio, Or Yehuda, Israel) is a novel technology designed for transcatheter repair of the mitral valve in the treatment of functional MR. Areas covered: A brief summary to direct the reader to important further reading, relevant websites; www.valtechcardio.com . An article about this device, relevant websites; www.ncbi.nlm.nih.gov/pubmed using search word 'Cardioband'. Expert commentary: This device has been designed to be completely implantable percutaneously in a closed beating heart fashion. The adjustability features under the beating heart and guided by echocardiography allow to provide a tailored therapy to each particular mitral valve and regurgitation condition.

Ongoing and future directions in percutaneous treatment of mitral regurgitation.

INTRODUCTION: Mitral regurgitation (MR) is one of the major valvular disease. Although surgical mitral valve (MV) repair is the standard of care for patients with severe MR, an unmet need exists in the management of patients with severe symptomatic MR and high surgical risk. Transcatheter MV therapies are alternative treatment option in such patients with moderate to severe and symptomatic MR. Areas covered: Literatures to direct the reader to important further reading were searched with relevant websites; www.ncbi.nlm.nih.gov/pubmed using search word 'transcatheter mitral intervention'. Expert commentary: A variety of transcatheter techniques have emerged for the percutaneous treatment of MR. We should carefully select one or combination procedure for each patient as an ideal tailor-made transcatheter MV therapy in order to improve the outcomes.

Management of Tricuspid Regurgitation: The Role of Transcatheter Therapies.

Surgical treatment is the gold standard treatment of functional tricuspid regurgitation (FTR) but this carries high risks of morbidity and mortality. Percutaneous procedures are an attractive alternative to surgery for selected patients deemed to be high-risk surgical candidates. A number of tricuspid transcatheter devices have been developed to treat FTR, but at present, evidence of their efficacy and safety is scarce. Preliminary data have shown promising results, but ongoing and future studies will provide a clearer picture of the benefits of these new techniques.

A creative transcatheter approach to correct complex recurring mitral regurgitation after previous surgical repair.

AIMS: Leaflet perforations are usually not treated by interventional therapy. In our case we describe a clinical scenario after previous surgical repair of mitral regurgitation combining several treatment strategies for correction. METHODS AND RESULTS: Under general anaesthesia, and using echocardiographic as well as fluoroscopic guidance, a transseptal approach was carried out and two MitraClips were implanted at the level of A2/P2. At completion echocardiography, a new large regurgitation jet was observed in the centre of the anterior mitral leaflet. We decided to proceed with the implantation of an 8 mm AMPLATZER ASD septal occluder device (AMPLATZER Septal Occluder; St. Jude Medical, St. Paul, MN, USA) to seal the defect. This was accomplished and final echo showed remaining trivial regurgitation from the coaptation area, while the perforation was completely sealed. The patient was discharged in a clinically improved condition. Pre-discharge transthoracic echocardiography showed the two MitraClips as well as the Amplatzer device in a stable correct position with trivial residual mitral regurgitation. CONCLUSIONS: The harmonisation of two diametral techniques for the treatment of recurring mitral regurgitation was effective in correcting the underlying problem. This approach may serve as an addition to the armamentarium of physicians treating patients with structural heart valve defects.

Transcatheter direct mitral valve annuloplasty with the Cardioband system for the treatment of functional mitral regurgitation.

Direct mitral valve annuloplasty is a transcatheter mitral valve repair approach that mimics the conventional surgical approach to treat functional mitral regurgitation. The Cardioband system (Valtech Cardio, Inc., Or-Yehuda, Israel) is delivered by a trans-septal approach and the implant is performed on the atrial side of the mitral annulus, under live echo and fluoroscopic guidance using multiple anchor elements. The Cardioband system obtained CE mark approval in October 2015, and initial clinical experiences are promising with regard to feasibility, safety and efficacy.

Transcatheter direct mitral annuloplasty with Cardioband: feasibility and efficacy trial in an acute preclinical model.

AIMS: The aim of the study was to report preclinical safety and feasibility of a new transcatheter direct mitral annuloplasty intervention in an acute animal model. METHODS AND RESULTS: Twenty healthy pigs underwent Cardioband (Valtech Cardio, Or Yehuda, Israel) transcatheter implantation under intracardiac echocardiographic and fluoroscopic guidance. Through a neo inferior vena cava approach, transseptal access was arranged. The device was delivered into the left atrium using a multi-steerable catheter and fixed to the mitral annulus with multiple helix anchors. Following device cinching, reduction of annular size was evaluated. In all animals the device could be successfully implanted and displayed 100% function, with the average procedure duration and fluoroscopy times being 78±23 minutes and 27±9 minutes, respectively. In total, 246 anchors (average 12.3 per device) were delivered and optimal anchor placement was achieved in 95.1%, while inadequate anchor position (4%) and injury of the coronary sinus or atrium (0.8%) occurred in the rest. Following maximal cinching, diastolic transmitral flow velocity and coaptation lengths were markedly increased (p<0.001), whereas septolateral and intercommissural distances were significantly decreased (p<0.001), when compared to pre-contraction baseline, demonstrating efficient annular reduction by the device. CONCLUSIONS: Transcatheter direct annuloplasty with a surgical-like adjustable device is feasible in the porcine animal model. The humanised porcine model has been instrumental in demonstrating feasibility and in establishing the procedural steps.

Percutaneous repair of the tricuspid valve using a novel cinching device: acute and chronic experience in a preclinical large animal model.

AIMS: The aim of this study was to evaluate the safety, technical feasibility and performance of a new trans-catheter tricuspid repair system. METHODS AND RESULTS: Thirty-one adult swine underwent implantation of a transcatheter tricuspid remodelling system under general anaesthesia. The steerable transcatheter device was introduced through a 24 Fr femoral sheath into the right femoral vein and delivered to the tricuspid annulus on the beating heart. A fixation element was implanted into the tricuspid annulus. Following implantation, a second delivery system was used to couple the fixation element with a self-expanding nitinol stent. The device was tensioned to reshape the tricuspid valve and increase the coaptation length of the valve leaflets under echo guidance. Finally, the stent was deployed in the inferior vena cava (IVC) to maintain the tension applied. The transcatheter device was successfully implanted in all animals (n=31). Doppler echocardiography prior to sacrifice showed that tricuspid valve function was stable and normal tricuspid leaflet motion was observed. Cinching of the tricuspid annulus resulted in an increase of leaflet coaptation length of 70% (4.5±0.7 mm to 7.78±1.3 mm), an increase in trans-tricuspid peak velocity of 79% (0.38±0.1 m/s to 0.68±0.1 m/s), and a reduction in septolateral tricuspid valve dimension of 30% (35.2±5 mm to 24.8±5 mm). At necropsy, the fixation element was firmly attached to the annulus within a fibrotic tissue, with no coronary lesions observed and no abnormality visible. The stent was fully deployed in the IVC, without displacement or change in the stent shape. CONCLUSIONS: Percutaneous beating heart remodelling of the tricuspid annulus with a cinching device is safe and feasible.

Right lateral mini-thoracotomy for mitral valve surgery.

Since the 1990 s, minimally invasive cardiac surgery has gained wide acceptance due to patient and economic demand. The advantages are less trauma, less bleeding, less wound infections, less pain and faster recovery. Many studies showed that the outcomes are comparable with those of conventional sternotomy. Right lateral mini-thoracotomy evolved into a routine and safe access in specialized centres for minimally invasive mitral valve surgery. The 6-cm incision is performed over the fifth intercostal space in the inframammary groove. With a double-lumen tube, the right lung is deflated before entering the pleural cavity. A soft tissue retractor is used to minimize rib spreading. The stab incisions for the endoscopic camera and the transthoracic clamp are performed in the right anterior and posterior axillary line in the third intercostal space. Surgery on the mitral valve is performed in a standard fashion under a direct vision with video assistance. One chest tube is inserted. The intercostal space is adapted with braided sutures to prevent lung herniation. Ropivacaine is used for local infiltration. The pectoral muscle, subcutaneous tissue and skin are adapted with running sutures. Complications of a right lateral mini-thoracotomy are rare (conversion to sternotomy, rethoracotomy, phrenic nerve palsy, wound infection and thoracic wall hernia) and well manageable.

Left anterior small thoracotomy for minimally invasive coronary artery bypass grafting.

Since the 1990 s, minimally invasive cardiac surgery has gained wide acceptance due to patient and economic demand. The advantages are less trauma, bleeding, wound infections, pain and faster recovery. Many studies showed that the outcomes are comparable with those of conventional sternotomy. Left anterior small thoracotomy (LAST) evolved into a routine and safe access in specialized centres for minimally invasive direct coronary artery bypass grafting. The 6-cm incision is localized above the fourth intercostal space, 3-4 cm lateral to the left sternal border and below the left mammilla. With a double-lumen tube, the left lung is deflated before entering the pleural space. The left internal mammary artery is harvested under direct vision with the use of special retractors. The anastomosis of the left anterior descending artery is performed on the beating heart as known from off-pump surgery. One chest tube is inserted. The intercostal space is closed with braided sutures to prevent lung herniation. Ropivacaine is used for local infiltration. The pectoral muscle, subcutaneous tissue and skin are closed with running sutures. Complications of the LAST approach are rare (conversion to sternotomy, re-thoracotomy, phrenic nerve palsy, wound infection and thoracic wall hernia) and well manageable.

Median sternotomy.

Sternotomy is considered to be the gold standard incision in cardiac surgery, resulting in low failure rates and excellent proven long-term outcomes. It can also be used in thoracic surgery for mediastinal, bilateral pulmonary or lower trachea and main stem bronchus surgery. Sternotomy has to be performed properly to avoid short- and long-term morbidity and mortality. The surgical technique is well established and certain principles are recognized to be crucial to minimize complications. The identification of the correct landmarks, midline tissue preparation, osteotomy with the avoidance of injury to underlying structures like pleura, pericardium, innominate vein, brachiocephalic artery and ectatic ascending aorta, and targeted bleeding control are important steps of the procedure. As important as the performance of a proper sternotomy is a correct sternal closure. An override or shift of the sternal edges has to be avoided by placing the wires at a proper distance from each other without injuring the thoracic pedicle. The two sternal halves have to be tightly re-approximated to facilitate healing of the bone and to avoid instability, which is a risk factor for wound infection. With a proper performance of sternotomy and sternal closure, instability and wound infections are rare and depend on patient-related risk factors.

Upper ministernotomy.

During the past 50 years, median sternotomy has been the gold standard approach in cardiac surgery with excellent long-term outcomes. However, since the 1990 s, minimally invasive cardiac surgery (MICS) has gained wide acceptance due to patient and economic demand. The advantages include less surgical trauma, less bleeding, less wound infections, less pain and faster recovery of the patients. One of these MICS approaches is the J-shaped upper ministernotomy which results in favourable long-term outcomes even in elderly and redo patients when compared with conventional sternotomy. Owing to its similarity to a full midline sternotomy, it has become the most popular MICS approach besides a mini-thoracotomy. It is a safe and feasible access, but certain recognized principles are mandatory to minimize complications. After identification of the landmarks, the 5-cm skin incision is performed in the midline between the second and fourth rib. The third or fourth right intercostal space is located and dissected laterally off the sternum. After osteotomy, the pericardium is pulled up with stay sutures which allow excellent exposure. The surgical procedures are performed in a standard fashion with central cannulation. Continuous CO2 insufflation is used to minimize the risk of air embolism. Epicardial pacing wires are placed before the removal of the aortic cross-clamp and one chest tube is used. Sternal closure is achieved with three to five stainless steel wires. The pectoral muscle, subcutaneous tissue and skin are adapted with resorbable running sutures. When performed properly, complications are rare (conversion, bleeding and wound infection) and well manageable.

Current challenges in interventional mitral valve treatment.

Transcatheter mitral valve therapies have emerged as an alternative option in high surgical risk or inoperable patients with severe and symptomatic mitral regurgitation (MR). As multiple technologies and different approaches will become available in the field of mitral valve interventions, different challenges are emerging, both patient- (clinical challenges) and procedure-related (technical challenges). This review will briefly explore the current open challenges in the evolving fields of interventional mitral valve treatment.

Pre-clinical In Vitro and In Vivo Models for Heart Valve Therapies.

Heart valve disease is a frequently encountered pathology, related to high morbidity and mortality rates. Animal models are interesting to investigate the causality but also underlying mechanisms and potential treatments of human heart valve diseases. Strongly believing that both in vivo and ex vivo models are fundamental to support research and development of new technologies, we here report some examples of heart valve disease models, which in our experience have been actively used to support the development of new valve therapies.