Percutaneous reduction of septal-to-lateral mitral annular distance to increase mitral leaflet coaptation length: Preclinical study results.

Objectives: Percutaneous indirect annuloplasty has emerged as a treatment strategy for functional/ischemic mitral regurgitation. This study sought to evaluate the feasibility of percutaneous indirect annuloplasty technique using a new device. Methods: The device has 3 components: the "saddle" inserted into the great cardiac vein, the "plug" positioned in the left ventricular outflow tract, and the "bridge," a transatrial suture connecting the 2 holding elements. The aim was to shorten the septal-to-lateral distance of the mitral annulus by pulling on the saddle element. The procedure was performed through venous access in healthy adult sheep. A dedicated catheter holding a needle was used to deploy the saddle into the great cardiac vein and pierce its wall toward the left atrium to deploy the expanded polytetrafluoroethylene suture that is part of the bridge. A catheter for transseptal puncture was inserted for crossing the interatrial septum and piercing the aortic-mitral curtain, thereby allowing the plug to be deployed. The plug was held in place by the second part of the expanded polytetrafluoroethylene bridge. The 2 parts of the bridge were then joined to reduce the septal-to-lateral mitral annular distance. The septal-to-lateral distance and the coaptation length at P2 level were measured before and after the procedure using echocardiography. Results: Overall, 10 animals were treated, 7 successfully. The mean procedure duration was 110 ± 81 minutes. Septal-to-lateral distance decreased from 3.8 mm to 2.6 mm (30%), and maximum increase of mitral leaflet coaptation was 4 mm. Conclusions: This new approach seems promising for percutaneous treatment of functional mitral regurgitation.

A Heart Surgery Simulator With an Integrated Supervision System for Self-Learning the Key Steps and Pitfalls of the Mitral Valve Repair: Initial Investigation.

INTRODUCTION: Over the years, surgical education has dramatically improved and has become increasingly innovative. Almost all educational programs in surgery now rely on sophisticated training boxes and simulators that enable surgical instruments to be handled and surgical procedures to be trained in a safe environment. However, simulators need constant feedback from supervising senior surgeons, who only have limited teaching time available. We describe a cardiac surgery simulator with an integrated supervision system for self-learning how to repair a mitral valve. METHODS: We developed a mitral surgery simulator with integrated sensors to generate, record, and display quantitative data on trainee performance in relation with the mitral valve repair procedure. A team of experienced cardiac surgeons defined critical areas of the model and an algorithm to identify inconsistent movements, in terms of error types and out-of-bound actions. The device provided real-time feedback on the accuracy of the stitches placed. Four experienced cardiac surgeons and 3 advanced cardiac-surgery used the simulator and were asked to evaluate specific parameters of the system on a scale ranging from 1 to 10. RESULTS: All surgeons completed a P2 resection, followed by implanting a 32-mm mitral ring. The simulator detected 2 stitches that were placed in dangerous zones and another stitch that was placed in an inappropriate position. Users scored the real tissue feeling and interactivity of the model 9.5/10. CONCLUSIONS: This heart-surgery simulator offers a real-life model for learning about and training in mitral valve surgery, which could potentially replace the experienced surgeon's teaching role.

Percutaneous increase of mitral leaflet coaptation length after mitral valve repair: results from a preclinical study.

OBJECTIVES: The failure of mitral repairs can be the result of inadequate leaflet coaptation length (CL< 8 mm at the A2-P2 level). A new annuloplasty ring conceived by the authors enables post-surgical CL increase using percutaneous balloon catheter technology. We conducted preclinical studies to assess the in vivo feasibility of the procedure and the safety of the postimplant deformable mitral ring. METHODS: The new annuloplasty ring allows the percutaneous and progressive displacement of each of the 3 anatomical regions of the posterior mitral annulus towards the anterior. Displacement is permanent and induced by an angioplasty balloon catheter inserted in a line connecting the ring to the subcutaneous tissue. Under general anaesthesia and cardiopulmonary bypass, healthy adult sheep had mitral annuloplasty. The device was implanted using the interrupted suture technique. The connection line exited the left atrium and reached the skin. Epicardial echocardiography allowed assessment of valve competence, leaflet CL, the mitral valve area and the mitral valve gradient. The mandrel was removed, and the dedicated catheter balloon was inserted into the connection line. The balloon was inflated in the P2 position under fluoroscopic control, and epicardial echocardiography was used to assess the functional parameters of the valve. One month later, the balloon was inserted again through the connection line; the P1 and P3 areas were deformed to increase CL. Valve parameters were measured again using transthoracic echocardiography. After 6 months, transthoracic echocardiography was used to assess the functional parameters of the valve. The sheep were sacrificed and autopsied. RESULTS: Ten adult sheep survived the procedure. A 30-mm ring was implanted in all the sheep, and the 6-month follow-up was uneventful for all of them. The CL increased by 100% (4.2 ± 2 mm-8.5 ± 2 mm, P < 0.001); the transmitral gradient increased from 2 ± 0.5 mmHg to 4 ± 0.5 mmHg (P < 0.001) and the effective orifice area decreased from 4.5 ± 0.6 cm2 to 3.5 ± 0.6 cm2 (30% reduction, P < 0.001). CONCLUSIONS: The device safely enabled a significant improvement of leaflet CL after mitral annuloplasty with an angioplasty-like technique, and the improvement was stable over time. The reshaping of the mitral annulus provided by this technology should benefit all patients having mitral repairs. The future of mitral regurgitation treatment is towards surgical correction followed by late, iterative, percutaneous adjustments of mitral leaflets coaptation.

A New Combined Technique Reducing the Risk of Paraplegia during Thoracoabdominal Aorta Replacement.

Acute spinal cord ischemia during thoracoabdominal aorta replacement is a dreadful complication. Existing tools (motor evoked potential [MEP] and somatosensory evoked potential [SSEP]) do not allow differentiating between central and peripheral paraplegia. Therefore, the surgeon often performs unnecessary reimplantation of intercostal arteries: this is time consuming, and significantly increases bleeding complications. We present a simple technique combining MEP and peripheral compound muscle action potential induced by posterior tibialis nerve stimulation, enabling the surgeon to quickly discriminate between central and peripheral neurologic injury. The surgeon has one more tool to drive in real time the optimal surgical strategy. This strategy guides the decision as to which side branches ought to be reimplanted, thus minimizing the risk of paraplegia.

Mastering Mitral Leaflets Coaptation After Valve Repair with Adjustable Mitral Annuloplasty Ring: Proof of Concept in Mock Loop Study.

This investigation sought to determine the feasibility of a novel mitral ring designed to reshape mitral annulus on beating heart, after surgery. The mitral ring is intended to improve mitral leaflets coaptation to correct residual and recurrent mitral regurgitations. It could also provide progressive correction of mitral regurgitation. The device was tested in ex vivo beating heart model. The novel mitral ring is selectively deformable in P1, P2, and P3 segments using a dedicated angioplasty-type balloon. The deformation should increase leaflets coaptation, reducing distance between the two leaflets. It was implanted using standard surgical techniques. The mock loop is based on passive beating heart. Mitral valve (MV) functioning was evaluated in terms of leaflets coaptation height at P2 level using epicardial echocardiography. The test has been completed on eight swine hearts. Ring size was 30 mm. The balloons were inserted in the connecting line. Each segment of the posterior annulus was independently activated over three progressive positions. Balloon inflation pressures were between 15 and 21 bar. Maximum coaptation height increase was 7 mm. Mean pressure gradient across the MV was 1.7 ± 0.3 mm Hg after complete activation of the device. The device allowed significant increase in coaptation height at P2 level after adjustments at P1, P2, and P3. Results were consistent and reproducible. This feasibility study demonstrates the possibility to reshape the mitral annulus on beating heart to precisely increase MV leaflets coaptation height.

New Insights in the Diagnosis and Treatment of Heart Failure.

Cardiovascular disease is the leading cause of mortality in the US and in westernized countries with ischemic heart disease accounting for the majority of these deaths. Paradoxically, the improvements in the medical and surgical treatments of acute coronary syndrome are leading to an increasing number of "survivors" who are then developing heart failure. Despite considerable advances in its management, the gold standard for the treatment of end-stage heart failure patients remains heart transplantation. Nevertheless, this procedure can be offered only to a small percentage of patients who could benefit from a new heart due to the limited availability of donor organs. The aim of this review is to evaluate the safety and efficacy of innovative approaches in the diagnosis and treatment of patients refractory to standard medical therapy and excluded from cardiac transplantation lists.

Aortic Annulus Stabilization Technique for Rapid Deployment Aortic Valve Replacement.

Rapid deployment aortic valve replacement (RDAVR) with the use of rapid deployment valve systems represents a smart alternative to the use of standard aortic bioprosthesis for aortic valve replacement. Nevertheless, its use is still debatable in patients with pure aortic valve regurgitation or true bicuspid aortic valve because of the risk of postoperative paravalvular leak. To address this issue, an optimal annulus-valve size match seems to be the ideal surgical strategy. This article describes a new technique developed to stabilize the aortic annulus and prevent paravalvular leak after RDAVR. To confirm the feasibility, this technique was performed in six patients with severe symptomatic aortic stenosis who were scheduled to undergo aortic valve replacement at our center. All patients survived surgery and were discharged from the hospital. There were no new intracardiac conduction system disturbances observed, and a permanent pacemaker implantation was not required in any of the patients. The intraoperative and postoperative echocardiogram confirmed successful positioning of the valve, and no paravalvular leak was observed. In this preliminary experience, RDAVR through a full sternotomy or an upper hemisternotomy approach with the use of aortic annulus stabilization technique was safe, and no leak was observed. Future studies on large series of patients are necessary to confirm the safety and effectiveness of this technique in preventing paravalvular leak in patients with true bicuspid aortic valves or pure aortic regurgitation.

Tropheryma whipplei bivalvular endocarditis and polyarthralgia: a case report.

INTRODUCTION: Tropheryma whipplei infection should be considered in patients with suspected infective endocarditis with negative blood cultures. The case (i) shows how previous symptoms can contribute to the diagnosis of this illness, and (ii) elucidates current recommended diagnostic and therapeutic approaches to Whipple's disease. CASE PRESENTATION: A 71-year-old Swiss man with a past history of 2 years of diffuse arthralgia was admitted for a possible endocarditis with severe aortic and mitral regurgitation. Serial blood cultures were negative. Our patient underwent replacement of his aortic and mitral valve by biological prostheses. T. whipplei was documented by polymerase chain reactions on both removed valves and on stools, as well as by valve histology. A combination of hydroxychloroquine and doxycycline was initiated as lifetime treatment followed by the complete disappearance of his arthralgia. CONCLUSIONS: This case report underlines the importance of considering T. whipplei as a possible causal etiology of blood culture-negative endocarditis. Lifelong antibiotic treatment should be considered for this pathogen (i) due to the significant rate of relapses, and (ii) to the risk of reinfection with another strain since these patients likely have some genetic predisposition.

Apical closure device for transapical valve procedures.

OBJECTIVES: Transapical transcatheter valve procedures are performed through a left minithoracotomy and require apical sutures to seal the apical access site. The use of large-calibre devices compromises any attempt to fully perform the procedure with a thoracoscopic approach or percutaneously. We report our preliminary experience in animals with a new sutureless self-expandable apical occluder, engineered to perform transapical access site closure in a minimally invasive setting with large-size introducer sheaths. METHODS: The apical occluder with extendable waist was implanted in six young pigs during an acute animal study. Under general anaesthesia, animals (mean weight: 62 ± 8 kg) received full heparinization (heparin: 100 UI/kg; activated clotting time above 250 s). Through a median sternotomy, a 21-Fr Certitude™ introducer sheath (outer diameter: 25 Fr) was placed over the wire into the cardiac apex. The delivery catheter carrying the constrained apical plug was inserted into the sheath and deployed under fluoroscopic control, whereas the Certitude™ was retrieved. After protamine infusion, we observed and recorded the 1-h bleeding with standard haemodynamic parameters. Animals were sacrificed, and hearts analysed. RESULTS: Six apical closure devices were successfully introduced and deployed in six pig hearts through large-size apical sheaths at first attempt. In all animals, the plugs guaranteed immediate apical sealing and traces of blood were collected in the pericardium during the 1-h observational period (mean of 16 ± 3.4 ml of blood loss per animal). Haemodynamic parameters remained stable during the entire study period and no plug dislodgement was detected with normal systemic blood pressure (mean arterial mean blood pressure: 65 ± 7 mmHg). Post-mortem analysis confirmed the full deployment and good fixation of all plugs, without macroscopic damages to the surrounding myocardium. CONCLUSIONS: This sutureless self-expandable apical occluder is a simple device capable of sealing large-size apical access sites (20-35 Fr) in an acute animal study. This approach is a step further towards less invasive transapical valve procedures in the clinical setting, and further animal tests will be performed to confirm the long-term efficacy and safety of this device.

'Fast-implantable' aortic valve implantation and concomitant mitral procedures.

Concomitant aortic and mitral valve replacement or concomitant aortic valve replacement and mitral repair can be a challenge for the cardiac surgeon: in particular, because of their structure and design, two bioprosthetic heart valves or an aortic valve prosthesis and a rigid mitral ring can interfere at the level of the mitroaortic junction. Therefore, when a mitral bioprosthesis or a rigid mitral ring is already in place and a surgical aortic valve replacement becomes necessary, or when older high-risk patients require concomitant mitral and aortic procedures, the new 'fast-implantable' aortic valve system (Intuity valve, Edwards Lifesciences, Irvine, CA, USA) can represent a smart alternative to standard aortic bioprosthesis. Unfortunately, this is still controversial (risk of interference). However, transcatheter aortic valve replacements have been performed in patients with previously implanted mitral valves or mitral rings. Interestingly, we learned that there is no interference (or not significant interference) among the standard valve and the stent valve. Consequently, we can assume that a fast-implantable valve can also be safely placed next to a biological mitral valve or next to a rigid mitral ring without risks of distortion, malpositioning, high gradient or paravalvular leak. This paper describes two cases: a concomitant Intuity aortic valve and bioprosthetic mitral valve implantation and a concomitant Intuity aortic valve and mitral ring implantation.

Artificial muscle to wash blood out of fibrillating atrium: an alternative to lifelong anticoagulation.

The Atripump is a motorless, volume displacement pump based on artificial muscle technology that could reproduce the pump function of normal atrium. It could help prevent blood clots due to blood stagnation and eventually avoid anticoagulation therapy in atrial fibrillation (AF). An animal study has been designed to assess mechanical effects of this pump on fibrillating atrium. The Atripump is a dome shaped silicone coated nitinol actuator. A pacemaker like control unit drives the actuator. In five adult sheep, the right atrium (RA) was exposed and dome sutured onto the epicardium. Atrial fibrillation was induced using rapid epicardial pacing (600 beats/min). Ejection fraction of the RA was obtained with intracardiac ultrasound in baseline, AF and Atripump assisted AF conditions. The dome's contraction rate was 60/min with power supply of 12V, 400 mA for 200 ms and ran for 2 hours in total. Mean temperature on the RA was 39+/-1.5 degrees C. Right atrium ejection fraction was 31% in baseline conditions, 5% and 20% in AF and assisted AF, respectively. In two animals a thrombus appeared in the right appendix and washed out once the pump was turned on. The Atripump washes blood out the RA acting as an anticoagulant device. Possible clinical implications in patients with chronic AF are prevention of embolism of cardiac origin and avoidance of hemorrhagic complication due to chronic anticoagulation.

Endovascular thoracic aortic aneurysm repair without angiography.

OBJECTIVE: : Intravascular ultrasound (IVUS) generates high definition circumferential cross-sectional images and provides real-time readout of vascular dimensions, including visualization of vessel branches. We have used it as an alternative to angiography in the endovascular thoracic aneurysm repair work-up. METHODS: : Out of consecutive 203 patients with descending thoracic aortic aneurysm, 89 (43.8%) received endovascular treatment [mean age, 68 ± 8 years; range, 29-82; male, 79 (88.7%); female, 10 (11.3%)] without using angiography during the endovascular procedure. IVUS (6 F, 12.5 MHz probe or 10 F 9 MHz) coupled with fluoroscopy for the placement of radiopaque markers was used for target site identification, landing zone measurement, device positioning, and assessment of endovascular repair. RESULTS: : Hospital mortality was 4/89 (4.5%). Number of devices implanted in each patient was 1.2 (range, 1-3). X-ray exposure time was 12 ± 8 minutes. Median procedure time was 63 ± 20 minutes. Conversion to open surgery was necessary in one patient (1.1%) because of aortic dissection. In nine patients (10.1%) left subclavian artery was covered because of a short neck. Two patients (2.2%) had vascular access lesions and required surgical repair. One patient developed paraplegia (1.1%). Early endoleak was observed in eight patients (8.9%) and 4 (4.5%) required additional procedures (proximal or distal extensions). Late conversion was necessary in one patient (1.1%). CONCLUSIONS: : IVUS provides all information necessary for device selection, target site identification as well as safe and correct deployment of thoracic endoprostheses and makes periprocedural angiography unnecessary, thus avoiding the risk of renal failure because of contrast medium.

Temporary caval stenting improves venous drainage during cardiopulmonary bypass.

OBJECTIVES: Assess the benefit of temporary caval stenting for remote venous drainage during cardiopulmonary bypass (CPB). METHODS: Temporary caval stenting was realized in bovine experiments (65+/-6 kg) by the means of self-expanding (18F for insertion, 36F in situ) venous cannulas (Smartcanula LLC, Lausanne, Switzerland) with various lengths: 43 cm, 53 cm, 63 cm vs. a standard 28F wire armed cannula in trans-jugular fashion. Maximal blood flows were assessed for 20, 25 and 30 mmHg of driving pressure with a motorized table height adjustment system. In addition, the inferior caval diameters (just above its bifurcation) were measured in real time with intra-vascular ultrasound (IVUS). RESULTS: Venous drainage (flow in l/min) at 20 mmHg, 25 mmHg, and 30 mmHg drainage load was 3.5+/-0.5, 3.7+/-0.7 and 4.0+/-0.6 for the 28F standard vs. 4.1+/-0.7, 4.0+/-1.3 and 3.9+/-1.1 for the 36F smart 43 cm, vs. 5.0+/-0.7, 5.3+/-1.3 and 5.4+/-1.4 for the 36F smart 53 cm, vs. 5.2+/-0.5*, 5.6+/-1.1* and 5.8+/-1.0* for the 36F smart 63 cm. The inferior vena caval diameters at 30 mmHg were 13.5+/-4.8 mm for 28F standard, 11.1+/-3.6 for 36F smart 43 cm, 11.3+/-3.2 for 36F 53 cm, and 17.0+/-0.1* for 36F 63 cm (*P<0.05 for 28F standard vs. 36F smart 63 cm long) CONCLUSIONS: The 43 cm self-expanding 36F smartcanula outperforms the 28F standard wire armed cannula at low drainage pressures and without augmentation. Temporary caval stenting with long self-expanding venous cannulas provides even better drainage (+51%).

Endoscopic access closure for direct implantation of valved stents.

OBJECTIVES: The off-pump trans left ventricular approach provides an alternative option for insertion of stented aortic valves of any size for endovascular replacement. One of the key steps in this procedure is the repair of the ventricle after catheter withdrawal. This study evaluates the reliability of a new device for sutureless and quick repair of the left ventricle access. METHODS: The Amplatz-nitinol occluder consists of two square heads that squeeze the ventricle wall between them thus sealing the ventricular defect. In four adult pigs weighing 55 kg, left thoracoscopy was performed to open the pericardium and visualise the cardiac apex. Following a heparin injection (100 U/kg) under ICUS and fluoroscopic control, we inserted a 30 F sheath into the epigastric area through the cardiac apex up into the left ventricle thus simulating the approach for an off-pump aortic valve replacement. The sheath was then removed and the ventricle closed with the occluder. Animals were followed-up for three hours; the haemodynamics and pericardial bleeding were recorded. The animals were then sacrificed and the gross anatomy of the heart was examined. RESULTS: The device was successfully deployed in four animals in less than one minute. ACT was above 200 seconds in all cases. All animals survived the procedure with a mean arterial pressure of 50 +/- 15 mm Hg. Bleeding during deployment was 80 +/- 20 ml and over a 3 hour period was 800 +/- 20 ml. Examination of the gross anatomy examination demonstrated the correct positioning of the device. CONCLUSIONS: The occluder is easy to use and the procedure is feasible and reproducible. However, the occluder design requires technical improvements in order to reduce bleeding before it can be used clinically.

Progress in cardiovascular anastomoses: will the vascular join replace Carrel's technique?

BACKGROUND: Vascular reconstructions are becoming challenging due to the comorbidity of the aging population and since the introduction of minimally invasive approaches. Many sutureless anastomosis devices have been designed to facilitate the cardiovascular surgeon's work and the vascular join (VJ) is one of these. We designed an animal study to assess its reliability and long-term efficacy. METHODS: VJ allows the construction of end-to-end and end-to-side anastomoses. It consists of two metallic crowns fixed to the extremity of the two conduits so that vessel edges are joined layer by layer. There is no foreign material exposed to blood. In adult sheep both carotid arteries were prepared and severed. End-to-end anastomoses were performed using the VJ device on one side and the classical running suture technique on the other side. Animals were followed-up with Duplex-scan every 3 months and sacrificed after 12 months. Histopathological analysis was carried out. RESULTS: In 20 animals all 22 sutureless anastomoses were successfully completed in less than 2 min versus 6 +/- 3 min for running suture. Duplex showed the occlusion of three controls and one sutureless anastomosis. Two controls and one sutureless had stenosis >50%. Histology showed very thin layer of myointimal hyperplasia (50 +/- 10 microm) in the sutureless group versus 300 +/- 27 microm in the control. No significant inflammatory reaction was detected. CONCLUSIONS: VJ provides edge-to-edge vascular repair that can be considered the most physiological way to restore vessel continuity. For the first time, in healthy sheep, an anastomotic device provided better results than suture technique.