Philipp Bonhoeffer

First-in-man implantation of a novel percutaneous valve: a new approach to medical device development.

AIMSnTo present our experience of first-in-man implantation of a new percutaneous pulmonary valve into a dilated pulmonary trunk, using patient specific data to influence the design of the device and ensure patient safety.nnnMETHODS AND RESULTSnA 42-year-old with severe pulmonary insufficiency underwent computed tomography assessment of his pulmonary trunk. This information was utilised to create computer and rapid prototyping models that were used to customise and test the device, which was subsequently implanted into the patient. Following the procedure, the clinical, haemodynamic and morphological success of this approach was determined. The new device was safely and successfully implanted as predicted by the pre-procedural modelling. There was excellent device stability, no stent fractures, no pulmonary incompetence and only trivial para-device leak at six months follow-up. The patient described marked symptomatic improvement.nnnCONCLUSIONSnSafe, effective percutaneous pulmonary valve implantation is possible in a patient with a dilated, native pulmonary trunk. Our methodologies, which have evolved as a direct result of recent advances in four-dimensional imaging techniques, challenge the conventional stepwise pathway of bench and animal testing prior to human application, and may be safer and more relevant, potentially reducing the number of animal experiments necessary for testing new medical devices.

Early Versus Late Functional Outcome After Successful Percutaneous Pulmonary Valve Implantation Are the Acute Effects of Altered Right Ventricular Loading All We Can Expect

OBJECTIVESnThe purpose of this study was to assess the potential of late positive functional remodeling after percutaneous pulmonary valve implantation (PPVI) in right ventricular outflow tract dysfunction.nnnBACKGROUNDnPPVI has been shown to impact acutely on biventricular function and exercise performance, but the potential for further late functional remodeling remains unknown.nnnMETHODSnSixty-five patients with sustained hemodynamic effects of PPVI at 1 year were included. Patients were divided into 2 subgroups based on pre-procedural predominant pulmonary stenosis (PS) (n = 35) or predominant pulmonary regurgitation (PR) (n = 30). Data from magnetic resonance imaging and cardiopulmonary exercise testing were compared at 3 time points: before PPVI, within 1 month (early) and at 12 months (late) after PPVI.nnnRESULTSnThere was a significant decrease in right ventricle end-diastolic volume early after PPVI in both subgroups of patients. Right ventricle ejection fraction improved early only in the PS group (51 ± 11% vs. 58 ± 11% and 51 ± 12% vs. 50 ± 11%, p < 0.001 for PS, p = 0.13 for PR). Late after intervention, there were no further changes in magnetic resonance parameters in either group (right ventricle ejection fraction, 58 ± 11% in the PS group and 52 ± 11% in the PR group, p = 1.00 and p = 0.13, respectively). In the PS group at cardiopulmonary exercise testing, there was a significant improvement in peak oxygen uptake early (24 ± 8 ml/kg/min vs. 27 ± 9 ml/kg/min, p = 0.008), with no further significant change late (27 ± 9 ml/kg/min, p = 1.00). In the PR group, no significant changes in peak oxygen uptake from early to late could be demonstrated (25 ± 8 ml/kg/min vs. 25 ± 8 ml/kg/min vs. 26 ± 9 ml/kg/min, p = 0.48).nnnCONCLUSIONSnIn patients with a sustained hemodynamic result 1 year after PPVI, a prolonged phase of maintained cardiac function is observed. However, there is no evidence for further positive functional remodeling beyond the acute effects of PPVI.

Direct Visualization of a Transcatheter Pulmonary Valve Implantation Within the Visible Heart A Glimpse Into the Future

The complexity of intracardiac interventions has increased with the advent of transcatheter valve replacement, and advanced imaging modalities will be required both to plan and to guide these interventions. The imaging modalities currently used have limited temporal and spatial resolution. We set out to take a glimpse into the future by demonstrating the exquisite picture quality of direct visualization of a Melody*† (Medtronic) transcatheter pulmonary valve implantation1–3 within the Visible Heart† (Medtronic).4 With the advent of major advances in visualization techniques (eg, trans-blood, enhanced 4-D), this imaging quality could …The complexity of intracardiac interventions has increased with the advent of transcatheter valve replacement, and advanced imaging modalities will be required both to plan and to guide these interventions. The imaging modalities currently used have limited temporal and spatial resolution. We set out to take a glimpse into the future by demonstrating the exquisite picture quality of direct visualization of a Melody*† (Medtronic) transcatheter pulmonary valve implantation 1–3 within the Visible Heart† (Medtronic). 4 With the advent of major advances in visualization techniques (eg, trans-blood, enhanced 4-D), this imaging quality could become a clinical reality. Endoscopic cameras were placed within the right ventricle of a human donor heart that was deemed not viable for transplantation. The heart was reanimated and perfused with a clear Krebs-Henseleit buffer according to previously described Visible Heart methodologies.4 Furthermore, this heart had an intrinsic rhythm and could sustain function in a 4-chamber working mode.4 Baseline systolic and diastolic right ventricular pressures were 35/4 mm Hg, and all steps of the transcatheter pulmonary valve implantation procedure could be monitored with direct visualization. Initially, a guidewire was positioned in the right ventricular outflow tract and across the native pulmonary valve (Data Supplement Movie I). Next, the delivery system was placed over the guidewire and advanced until the valve was properly positioned at the native pulmonary valve. Once in position, the transcatheter pulmonary valve was unsheathed. The overlay sheath protected the leaflets and chordae of the tricuspid valve from any damage that could have been caused by the collapsed stent of the transcatheter valve. The first balloon of the double-balloon delivery system was then inflated, partially deploying the valve. Finally, the second balloon of the delivery system was inflated, and the deployed transcatheter pulmonary valve could be observed (Data Supplement Movie I). Shown in Data Supplement Movie II is the implanted, functioning transcatheter pulmonary valve as viewed from the right ventricular outflow tract and from the pulmonary trunk, providing qualitative assessment of performance. The Visible Heart methodology provides imaging that should be considered the gold standard for clinical imaging modalities. At present, it offers new opportunities for in vitro and bench testing of new devices.

Images in cardiovascular medicine. Direct visualization of a transcatheter pulmonary valve implantation within the visible heart: a glimpse into the future.

The complexity of intracardiac interventions has increased with the advent of transcatheter valve replacement, and advanced imaging modalities will be required both to plan and to guide these interventions. The imaging modalities currently used have limited temporal and spatial resolution. We set out to take a glimpse into the future by demonstrating the exquisite picture quality of direct visualization of a Melody*† (Medtronic) transcatheter pulmonary valve implantation1–3 within the Visible Heart† (Medtronic).4 With the advent of major advances in visualization techniques (eg, trans-blood, enhanced 4-D), this imaging quality could …The complexity of intracardiac interventions has increased with the advent of transcatheter valve replacement, and advanced imaging modalities will be required both to plan and to guide these interventions. The imaging modalities currently used have limited temporal and spatial resolution. We set out to take a glimpse into the future by demonstrating the exquisite picture quality of direct visualization of a Melody*† (Medtronic) transcatheter pulmonary valve implantation 1–3 within the Visible Heart† (Medtronic). 4 With the advent of major advances in visualization techniques (eg, trans-blood, enhanced 4-D), this imaging quality could become a clinical reality. Endoscopic cameras were placed within the right ventricle of a human donor heart that was deemed not viable for transplantation. The heart was reanimated and perfused with a clear Krebs-Henseleit buffer according to previously described Visible Heart methodologies.4 Furthermore, this heart had an intrinsic rhythm and could sustain function in a 4-chamber working mode.4 Baseline systolic and diastolic right ventricular pressures were 35/4 mm Hg, and all steps of the transcatheter pulmonary valve implantation procedure could be monitored with direct visualization. Initially, a guidewire was positioned in the right ventricular outflow tract and across the native pulmonary valve (Data Supplement Movie I). Next, the delivery system was placed over the guidewire and advanced until the valve was properly positioned at the native pulmonary valve. Once in position, the transcatheter pulmonary valve was unsheathed. The overlay sheath protected the leaflets and chordae of the tricuspid valve from any damage that could have been caused by the collapsed stent of the transcatheter valve. The first balloon of the double-balloon delivery system was then inflated, partially deploying the valve. Finally, the second balloon of the delivery system was inflated, and the deployed transcatheter pulmonary valve could be observed (Data Supplement Movie I). Shown in Data Supplement Movie II is the implanted, functioning transcatheter pulmonary valve as viewed from the right ventricular outflow tract and from the pulmonary trunk, providing qualitative assessment of performance. The Visible Heart methodology provides imaging that should be considered the gold standard for clinical imaging modalities. At present, it offers new opportunities for in vitro and bench testing of new devices.

Patients' and physicians' needs, experiences and preferences in the treatment of right ventricular outflow tract dysfunction

Background : patients with congenital heart defects, developing right ventricular outflow tract (rVoT) dysfunction, can face repeated open chest interventions over their lifetime. repeating surgery increases difficulties and procedural risks, and exposes patients to burdensome and long recovery times that may induce them to postpone the treatment, with possible severe and irreversible consequences for their health. The percutaneous procedure was introduced to delay the need for open chest surgery. uncertainties still exist regarding the lifelong consequences that may result from adopting different treatment strategies. current decisions on treatment depend on patients’ clinical needs, but also on physicians’ experience and opinion, patients’ preferences, and procedural costs. The objective is to identify which treatment characteristics influence decisions on how to treat patients with rVoT dysfunction. Methods : a literature review was conducted, followed by a discussion with a panel of experts. Ten treatment characteristics, potentially relevant for treatment, were identified and rated in a survey, according to the importance assigned to each characteristic by specialist physicians, patients and/or their caregivers. Results : while some characteristics appear to be more important (risk of severe complications associated with intervention delays) or less important (scar) to both physicians and patients/caregivers, other characteristics are rated differently in importance depending on subjects consulted, e.g., risk of complications during the months post intervention was among the most important characteristics for patients/caregivers, but the fifth most important characteristic for physicians. Conclusions : to optimize benefits and efficiency of the treatment strategies, perceptions and opinions from the different subjects involved, together with patients’ clinical needs and overall costs, should be considered in decision-making....

Different Finite Element Strategies to Satisfy Clinical and Engineering Requirements in Modeling a Novel Percutaneous Device

By taking into account patient-specific properties, finite element (FE) models can aid in the optimization of the devices’ mechanical performances, accelerating the time of development and reducing testing costs. Patient-specific cardiovascular modeling can also drive the development of novel devices [1], by means of anatomical elements that are more representative than animal surrogates [2], and integrating standard in vitro tests with patient-specific loading conditions [3]. Transcatheter heart valve implantation can particularly benefit from a modeling approach. In the field of treatment of valve dysfunctions, percutaneous techniques are relatively new or under development, and modeling tools can contribute to improve these procedures (e.g. design modifications or different routes for device insertion) and increase patient safety in the early introduction of new devices into clinical practice. For a feasible clinical application, computational methods need to be fully validated against physical data, to take into account patient-specific properties, and to provide results in a short time. Instead, from an engineering perspective, models can cost-effectively aid the design phase by improving preclinical testing with more realistic loading conditions for accurate simulation of mechanical behaviour and prediction of durability. This study aims to identify optimal modeling strategies to respond to both clinical and engineering requirements. As a case study, simulations were conducted on a new percutaneous pulmonary valve implantation (PPVI) device [4] tested within a patient-specific right ventricular outflow tract model.© 2012 ASME