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Here, we provide a novel concept demonstrating that heart valve tissue engineering based on a minimally invasive technique for both cell harvest and valve delivery as a one-step intervention is feasible in non-human primates. This innovative approach may overcome the limitations of contemporary surgical and interventional bioprosthetic heart valve prostheses.

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BACKGROUND: Percutaneous mitral valve repair (MVR) using the MitraClip system has become a valid alternative for patients with severe mitral regurgitation (MR) and high operative risk. OBJECTIVE: To identify clinical and periprocedural factors that may have an impact on clinical outcome. DESIGN: Multi-centre longitudinal cohort study. SETTING: Tertiary referral centres. PATIENTS: Here we report on the first 100 consecutive patients treated with percutaneous MVR in Switzerland between March 2009 and April 2011. All of them had moderate-severe (3+) or severe (4+) MR, and 62% had functional MR. 82% of the patients were in New York Heart Association (NYHA) class III/IV, mean left ventricular ejection fraction was 48% and the median European System for Cardiac Operative Risk Evaluation was 16.9%. INTERVENTIONS: MitraClip implantation performed under echocardiographic and fluoroscopic guidance in general anaesthesia. MAIN OUTCOME MEASURES: Clinical, echocardiographic and procedural data were prospectively collected. RESULTS: Acute procedural success (APS, defined as successful clip implantation with residual MR grade 2+) was achieved in 85% of patients. Overall survival at 6 and 12 months was 89.9% (95% CI 81.8 to 94.6) and 84.6% (95% CI 74.7 to 91.0), respectively. Univariate Cox regression analysis identified APS (p=0.0069) and discharge MR grade (p=0.03) as significant predictors of survival. CONCLUSIONS: In our consecutive cohort of patients, APS was achieved in 85%. APS and residual discharge MR grade are important predictors of mid-term survival after percutaneous MVR.

The trial is registered at www.ClinicalTrials.gov, reference: NCT00567515.

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Objectives: We investigate the combination of transcatheter aortic-valve implantation (TAVI) and a novel concept of stem cell-based, tissue-engineered heart-valves (TEHV) comprising minimally-invasive techniques for both, cell-harvest and valve-delivery. Background: TAVI represents an emerging technology for the treatment of aorticvalve disease. The utilized bioprostheses are inherently prone to calcific-degeneration and recent evidence suggests even accelerated degeneration resulting from structuraldamage due to the crimping-procedures. Autologous, living heart-valve prosthesis with regeneration and repair capacities would overcome such limitations. Methods: Within a one-step intervention, tri-leaflet TEHV, generated from biodegradable synthetic-scaffolds, were integrated into self-expanding nitinol-stents, seeded with autologous bone-marrow mononuclear cells, crimped and transapically delivered into adult sheep (n=12). The animals were followed up for up to 2weeks. TEHV-functionality was assessed by fluoroscopy, echocardiography and computedtomography. Post-mortem analysis was performed using histology, extracellular-matrix analysis and electron-microscopy. Results: Transapical aortic implantation of TEHV was successful in all animals (n=12) and the entire procedure-time from cell-harvest to TEHV-delivery was 109±14min. Fluoroscopy and echocardiography displayed TEHV-functionality demonstrating an adequate leaflet-mobility and co-aptation. Explanted TEHV showed intact leafletstructures with well defined cusps without signs of thrombus-formation or structuraldamage. Histology and ECM analysis displayed a high cellularity indicative for an early cellular-remodelling and in-growth after 2weeks. Conclusion: For the first time, we demonstrate the principal feasibility of a transcatheter, stem cell-based TEHV implantation into the aortic-valve position within a one-step intervention. Its long term functionality proven, a stem cell-based TEHV 3 approach may represent a next generation heart-valve concept extending the clinical indication of transcatheter valves beyond elderly high-risk patients.

Although the preferential location of side branches may be addressed by the deliberate discarding of infragenicular vein segments, a diameter constriction of 27% on average would eliminate diameter irregularities in 98% of vein grafts.