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ObjectivesTo evaluate applicability and feasibility of the virtual imaging technology for diagnosis and planning of the aortic valve sparing procedure.MethodsPre-operative electrocardiography-gated computed tomography images of 12 adult patients with aortic root pathology were used for 3D reconstruction of the aortic root geometry. The structural analysis was conducted with focusing on spatial architecture of key aortic root structures such as the three commissures, intervalvular triangles (IVT), as well as on morphology of the aortic root base (AoB) and of the sinotubular junction (STJ).ResultsIn all included patients, the 3D mapping of aortic root (AoR) morphology was successfully performed. The pre-operative diameter of the AoB was 30.6 ± 2.6 mm and of the STJ 46.5 ± 7.5 mm (p < 0.001). Based on measured AoB diameter, the mean size of prosthesis used was 28.3 ± 1.37 mm. The planar arrangement of the three commissures was similar to an equilateral triangle where the three commissures were at similar distance for each individual sinus with 39.8 ± 6.64 mm for right, 37.5 ± 7.10 mm for left, and 39.2 ± 7.52 mm for non-coronary sinus (p = 0.72) subsequently. The similar height of the three IVT’s with 32.6 ± 5.87 mm for right, 33.6 ± 6.14 mm for anterior, and 31.7 ± 5.83 mm for left IVT (p = 0.73) was suggestive for all three commissures being positioned in the same plane. Consequently at reimplantation, the orientation of the three commissures followed the pattern of an equilateral triangle.ConclusionThe reconstructed images revealed a detailed 3D anatomy of the aortic root, with the spatial arrangement of the intervalvular triangles, planimetric orientation of the commissures, as well as determination of the AoB and STJ diameters. Obtained information was successfully applied to pre-operative surgical planning. The reimplantation technique, the height of the reimplanted intervalvular triangles, as well as their orientation are crucial for achieving adequate aortic valve function.

Background In view of the rising global burden of severe symptomatic aortic stenosis, its early recognition and treatment is key. Although patients with classical low-flow, low-gradient (C-LFLG) aortic stenosis have higher rates of death after transcatheter aortic valve implantation (TAVI) when compared with patients with high-gradient (HG) aortic stenosis, there is conflicting evidence on the death rate in patients with severe paradoxical low-flow, low-gradient (P-LFLG) aortic stenosis. Therefore, we aimed to compare outcomes in real-world patients with severe HG, C-LFLG, and P-LFLG aortic stenosis undergoing TAVI. Methods and Results Clinical outcomes up to 5 years were addressed in the 3 groups of patients enrolled in the prospective, national, multicenter SwissTAVI registry. A total of 8914 patients undergoing TAVI at 15 heart valve centers in Switzerland were analyzed for the purpose of this study. We observed a significant difference in time to death at 1 year after TAVI, with the lowest observed in HG (8.8%) aortic stenosis, followed by P-LFLG (11.5%; hazard ratio [HR], 1.35 [95% CI, 1.16-1.56]; P

The measure of left atrial pressure (LAP) is an ideal marker for the clinical efficacy of transcatheter mitral valve intervention. Currently, only the invasive measurement of LAP (i-LAP) is available and no echocardiographic methods are reliable in the setting of trans- catheter mitral valve intervention. This study sought to validate a new echocardiographic method for the estimation of LAP (e-LAP) by comparing it with i-LAP. During percutane- ous edge-to-edge procedure with MitraClip, the i-LAP was routinely monitored. Across the iatrogenic interatrial septum defect, the flow was sampled with continuous-wave Dopp- ler echocardiography for deriving the mean pressure gradient between the left atrium and the right atrium, and the central venous pressure was added to obtain the e-LAP. The cor- relation between the measures derived from these 2 methods was explored. A total of 34 consecutive patients were included. Intraclass correlation coefficient between e-LAP and i-LAP was high (intraclass correlation coefficient [95% confidence interval] 0.809 [0.625 to 0.902], R Pearson 0.6, p found (p = 0.32). The median follow-up was 108 days (interquartile range 40 to 264). No death occurred and 6 patients were rehospitalized for heart failure. Postimplant e-LAP was correlated with rehospitalization at follow-up (hazard ratio 1.46, 95% confidence interval 1.022 to 2.1, p = 0.038). A cut-off value of 9.5 mm Hg for the e-LAP was identified as predictor of rehospitalization for heart failure. The evaluation of e-LAP has optimal reliability compared with i-LAP; a value more than 9.5 mm Hg was found to be related to higher risk of events at short follow-up. © 2022 Elsevier Inc. All rights reserved. (Am J Cardiol 2022;00:1−8)

OBJECTIVES The aim of this study was to investigate age-related outcomes of patients undergoing transcatheter aortic valve replacement (TAVR) as assessed in a nationwide, prospective, multicenter cohort study. BACKGROUND TAVR is the preferred treatment for elderly patients with severe aortic stenosis and is expanding into lower age groups. METHODS Data from the SwissTAVI Registry were analyzed. Clinical outcomes were compared between patients 70 years of age or younger (n = 324), 70 to 79 years of age (n = 1,913), 80 to 89 years of age (n = 4,353), and older than 90 years of age (n = 507). Observed deaths were correlated with expected deaths in the general Swiss population using standardized mortality ratios. RESULTS Between February 2011 and June 2018, 7,097 patients (mean age 82.0 ± 6.4 years, 49.6% women) underwent TAVR at 15 hospitals in Switzerland. Procedural characteristics were similar; however, older patients more often had discharge to the referring hospital or a rehabilitation facility after TAVR. Using adjusted analyses, a linear trend for mortality (30-day adjusted hazard ratio [HRadj]: 1.45; 95% confidence interval [CI]: 1.18 to 1.77; 1-year HRadj: 1.12; 95% CI: 1.01 to 1.24), cerebrovascular accidents (30-day HRadj: 1.35; 95% CI: 1.09 to 1.66; 1-year HRadj: 1.21; 95% CI: 1.02 to 1.45), and pacemaker implantation (30-day HRadj: 1.23; 95% CI: 1.12 to 1.34; 1-year HRadj: 1.19; 95% CI: 1.09 to 1.30) was observed with increasing age. Furthermore, standardized mortality ratios were 12.63 (95% CI: 9.06 to 17.58), 4.09 (95% CI: 3.56 to 4.74), 1.63 (95% CI: 1.50 to 1.78), and 0.93 (95% CI: 0.76 to 1.14) for TAVR patients in relation to the Swiss population

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Transcatheter aortic root repair (TARR) is still not available because of the complex anatomy. In order to develop future TARR technologies, a human-derived bench test model is required before performing animal tests. For this purpose, we aimed to validate computed tomography (CT)-derived 3D-printed root models for TARR technologies. Four human CT-derived roots were printed using different resins: Visijet M3 Crystal, Photopolymer gel SUP705, Formlabs flexible resin, and Materialise HeartPrint Flex. A stress test was performed using a 26-mm balloon-expandable Sapien valve deployed in aortic position. The too rigid Visijet M3 Crystal was not tested. Among the others, all but one (HeartPrint Flex, Materialise, Leuven, Belgium) ruptured during the test showing low wall resistances. Further tests were then performed in two roots made of HeartPrint Flex resin. The anatomic validation was performed comparing human CT scan-derived 3D reconstructions and CT scan measurements: a mean difference of 0.57 ± 0.4 mm for aortic annulus diameter and for the distance between the aortic annulus and the coronary ostia was measured. Concerning the coronary arteries, they are of paramount importance for new TARR technologies, and therefore, we tested the coronary flows of the HeartPrint Flex root at different pressure levels. At 60 mm Hg, right and left mean adjusted coronary flows were 471 and 663 ml/min; at 80 mm Hg, right and left mean coronary flows were 551 and 777 ml/min; and at 100 mm Hg, right and left mean coronary flows were 625 and 858 ml/min. In our study, 3D-printed root models correlate well with human anatomy and guarantee physiologic coronary flows for TARR technologies.

OBJECTIVES Transcatheter aortic root repair (TARR) consists of the simultaneous endovascular replacement of the aortic valve, the root and the proximal ascending aorta. The aim of the study is to set-up a computational model of TARR to explore the impact of the endovascular procedure on the coronary circulation supported by chimney grafts. METHODS Computed tomography of a patient with dilated ascending aorta was segmented to obtain a 3-dimensional representation of the proximal thoracic aorta, including aortic root and supra-aortic branches. Computed assisted design tools were used to modify the geometry to create the post-procedural TARR configuration featuring the main aortic endograft integrated with 2 chimney grafts for coronary circulation. Computational Fluid Dynamics simulations were run in both pre- and post-procedural configurations using a pulsatile inflow and lumped parameter models at the outflows to simulate peripheral aortic and coronary circulation. Differences in coronary flow and pressure along the cardiac cycle were evaluated. RESULTS After the virtual implant of the TARR device with coronary grafts, the flow became more organized and less recirculation was seen in the ascending aorta. Coronary perfusion was guaranteed with negligible flow differences between pre- and post-procedural configurations. However, despite being well perfused by chimney grafts, the procedure induces an increase of the pressure drop between the coronary ostia and the ascending aorta of 8 mmHg. CONCLUSIONS The proposed numerical simulations, in the specific case under investigation, suggest that the TARR technique maintains coronary perfusion through the chimney grafts. This study calls for experimental validation and further analyses of the impact of TARR on cardiac afterload, decrease of aortic compliance and local pressure drop induced by the coronary chimney grafts.

OBJECTIVES Transcatheter aortic root repair is still not available because of the technical challenge of coronary perfusion. The use of chimney grafts for coronary ostia can be an option and we tested the flow-through coronary chimney grafts deployed in a 3-dimensional-printed root model as part of a transcatheter aortic root repair system. METHODS A 3-dimensional-printed root was used to test the coronary flow after the deployment of 1 root endograft (28 mm diameter) and two 6-mm diameter 10-cm long coronary chimney grafts. Continuous coronary flows were measured in a bench test at different pressure levels (60, 80 and 100 mmHg) and compared to target coronary flows (250 ml/min at rest for the left and 150 ml/min at rest for the right coronary artery). RESULTS The computed tomography scan-based root was modified with two 5-mm diameter coronary conduits to overcome the limits of the original 3-dimensional-printed coronary ostia. The root was placed in the hydrodynamic system: adjusted coronary free flow at 60, 80 and 100 mmHg of pressure was 1913, 2200 and 2480 ml/min for left coronary and 1633, 2026 and 2366 ml/min for right coronary, respectively. After endografts deployment, mean chimney graft flow at 60, 80 and 100 mmHg of pressure was 1053 ml/min (−45%), 1306 ml/min (−41%) and 1502 ml/min (−40%) for the left coronary and 1100 ml/min (−33%), 1460 ml/min (−28%) and 1626 ml/min (−31%) for the right coronary, respectively. CONCLUSIONS In this preliminary study, chimney grafts for transcatheter aortic root repair provided 830% of target flow in the right coronary (−31% of free flow) and 414% of target flow in the left coronary (−42% of free flow) which is more than sufficient for both coronaries in real-life conditions. The potential of this approach should be further explored with specifically designed endografts.

This chapter contributes a short tutorial on the preparation of molecular dynamics (MD) simulations for a peptide in solution at the interface of an uncoated gold nanosurface. Specifically, the step-by-step procedure will give guidance to set up the simulation of a 16 amino acid long antimicrobial peptide on a gold layer using the program Gromacs for MD simulations.

Objective Inadequate peripheral venous drainage during minimally invasive cardiac surgery (MICS) is a challenge and cannot always be solved with increased vacuum or increased centrifugal pump speed. The present study was designed to assess the benefit of virtually wall-less transfemoral venous cannulas during MICS. Methods Transfemoral venous cannulation with virtually wall-less cannulas (3/8″ 24F 530–630-mm ST) was performed in 10 consecutive patients (59 ± 10 years, 8 males, 2 females) undergoing MICS for mitral (6), aortic (3), and other (4) procedures (combinations possible). Before transfemoral insertion of wall-less cannulas, a guidewire was positioned in the superior vena cava under echocardiographic control. The wall-less cannula was then fed over the wire and connected to a minimal extracorporeal system. Vacuum assist was used to reach a target flow of 2.4 l/min per m2 with augmented venous drainage at less than −80 mm Hg. Results Wall-less venous cannulas measuring either 630 mm (n = 8) in length or 530 mm (n = 2) were successfully implanted in all patients. For a body size of 173 ± 11 cm and a body weight of 78 ± 26 kg, the calculated body surface area was 1.94 ± 0.32 m2. As a result, the estimated target flow was 4.66 ± 0.78 l/min, whereas the achieved flow accounted for 4.98 ± 0.69 l/min (107% of target) at a vacuum level of 21.3 ± 16.4 mm Hg. Excellent exposure and “dry” intracardiac surgical field resulted. Conclusions The performance of virtually wall-less venous cannulas designed for augmented peripheral venous drainage was tested in MICS and provided excellent flows at minimal vacuum levels, confirming an increased performance over traditional thin wall cannulas. Superior results can be expected for routine use.

Transcatheter mitral valve replacement with the Tiara valve can be performed in inoperable patients with severe functional regurgitation. Risk of left ventricular outflow tract obstruction can be prevented using preoperative 3D imaging and 3D-printed models. However, in the case of mono-disk mechanical prostheses previously implanted in aortic position (Bjork-Shiley), there is an additional risk of mechanical interference leading to reduced leaflet motion and aortic valve dysfunction. Hereafter, we describe the case of a patient with a 27-mm mono-disk mechanical aortic valve implanted in 1978, a EuroSCORE II of 18%, and a Society of Thoracic Surgeon score (mortality) of 16% who successfully underwent a transapical Tiara valve implantation.

Transcatheter aortic valve replacement (TAVR) is a major advancement in the treatment of severe aortic valve stenosis in elderly high-risk patients. Implementing TAVR also in younger intermediate- or low-risk patients increases interest in the possibility of further lowering the risk of perioperative cerebrovascular events. To this aim, some embolic protection devices (EPDs) have been developed, some of which have already been approved for clinical use. Nevertheless, the cause of cerebrovascular events after TAVR is multifactorial, and selection of patients who would benefit from EPD is crucial to further improve outcomes, survival rate and quality of life. We reviewed the available literature in order to assess the incidence of and the mechanisms responsible for neurological events that can occur during TAVR, and we analysed clinical results and imaging findings following EPD use. Clinical trials for Embrella, TriGuard, Sentinel and Embol-X devices were designed to test their safety and their ability to prevent neurological complications in patients having TAVR. So far, published results showed that EPD may help in reducing the volume and size of periprocedural silent ischaemic brain lesions identified on magnetic resonance images but not in reducing the incidence of new lesions and new neurological events. The clinical impact of EPD in lowering the number of transient ischaemic attacks/strokes during TAVR needs to be further investigated in randomized trials.

Objectives Given the similarities between coronary ostia and renal arteries, chimney grafts (CG) for kidney perfusion during abdominal endovascular aneurysm repair (EVAR) can be considered for coronary perfusion in future transcatheter aortic root repair (TARR) techniques. We analysed the results of renal CG and compared anatomic and technical details with root and coronary anthropometric data. Methods Current status of kidney perfusion with CG was reviewed from literature. Anatomic details, technical data, CG performance and clinical outcome were collected and analysed. Anatomic details of aortic landing zone and renal arteries were compared with human anthropometric data of aortic root, ascending aorta and coronary ostia. Results Seventeen articles reported 430 patients (mean age:74.5 ± 2.9 years) treated with renal CG. Mean length and diameter of proximal landing zone were 2.0 ± 2.0 mm and 26.4 ± 4.3 mm, respectively (anthropometric correspondence: ascending aorta diameter of 29.3 mm). Aortic endograft mean diameter was 26.4 ± 7.3 mm with reported oversize of 19.5 ± 6.0%. In total, 590 renal arteries were treated (left:325; right:265; bilateral:139 cases). Mean left and right renal artery diameters were 5.7 ± 0.6 mm and 5.8 ± 0.7 mm, respectively (anthropometric correspondence: coronary ostia diameters of 4.8 mm (left) and 3.7 mm (right)) with reported CG oversize of 19.75 ± 6% (left) and 18.1 ± 5.1% (right). Mean follow-up time was 16.5 ± 8.5 months, CG occlusion rate was 3.2% and endoleak I or II was reported in 83 patients (19.3%), requiring 7 procedures. Conclusions CG provides satisfactory results in patients with suitable renal artery diameter. Based on aortic root and coronary anthropometric data, CG can be considered in future TARR technologies for coronary perfusion but further tests for flow evaluations are mandatory.

Background We investigated hospital and midterm outcome of patients operated for an aortic valve replacement (AVR) with a pericardial Perimount or a Porcine Hancock-II valve. Methods We analyzed 353 patients with Perimount Magna (n = 189) or Hancock-II valves (n = 164). Echocardiographic data, hospital outcome, and follow-up were collected and compared. The role of the type of valve on perioperative and midterm outcome was investigated. Results Mean age was 75.3 ± 6.8 and 74.3 ± 7.1 years (P = .17) for Perimount and Hancock-II group, respectively. Fifty-four Perimount (28.6%) and 24 patients with Hancock-II (14.6%) required urgent procedures (P = .002), including six type-A dissections and five endocarditis. EuroSCORE-II was 3.1 ± 2.7% (Perimount) and 2.7 ± 2.2% (Hancock-II). Combined procedures were performed in 115 Perimount (60.8%) and 71 patients with Hancock (43.3%); redo procedures counted for 1% and 2.4%, respectively (P = .42). Mean valve size was 23.2 ± 1.8 mm for pericardial and 23.6 ± 1.9 mm for porcine valves (P = .08). Hospital mortality (6.3% vs 2.4%; P = .05), kidney failure (11.6% vs 9.8%; P = .73), and new pacemaker implantation rates (6.3% vs 3.0%; P = .21) were higher in the Perimount group reflecting the fact that more urgent, combined, and critical procedures were implanted with a Perimount Magna. Overall, 51 patients died over 60 months (34 Perimount, 17 Hancock), corresponding to a mortality of 5.3 per 100-persons year (95% confidence interval [CI]: 3.8-7.4) and 3.0 (95% CI: 1.8-4.8), respectively. Survival at 5 years was 76% (95% CI: 68-82) and 83% (95% CI: 74-89) in the Perimount and Hancock groups (log-rank test; P = .099). Conclusions We confirm a good clinical outcome of patients with AVR with modern pericardial or a porcine bioprosthesis. Despite better hemodynamic, the Perimount does not improve the midterm clinical outcome compared with the porcine valve.

Severe ascending aorta disease includes aneurysms, pseudoaneurysms (ascending aorta pseudoaneurysms), penetrating aortic ulcers and Type A aortic dissections. Surgical replacement of the aortic root, ascending aorta or aortic arch is the common treatment for severe ascending aortic disease involving the root, the ascending aorta and/or the arch. Despite good surgical results, there is still a risk for morbidity and mortality following surgery for ascending aorta replacement when elderly patients or patients at high risk for surgery are concerned. Less invasive endovascular treatments for ascending aorta repair are under evaluation, and some reports appeared in the available literature in the last decade. However, clinical series or randomized studies are not yet available, and the use of these techniques is still questionable. In this study, we analysed the outcomes of reported cases of endovascular treatment for ascending aorta disease, excluding Type A aortic dissection. We reviewed reports published until February 2017, and we evaluated the employed technology, the devices, the procedural steps and the outcomes. A total of 26 articles reported 67 patients (mean age 65 ± 17 years) who received endovascular treatment for ascending aorta disease: aneurysms, ascending aorta pseudoaneurysms, penetrating aortic ulcers, intramural haematoma, thrombosis, iatrogenic coarctation and aortic rupture. Complications included endoleak (9 cases), stroke (3 cases), non-ST-elevation myocardial infarction (1 case) and splenic infarction (1 case). Three patients required conversion to open surgery, and 1 patient underwent endovascular reintervention. Early mortality was 2.9%. As an alternative treatment for ascending aorta disease in selected high-risk patients, the endovascular repair will gain popularity, but further analysis is required.

Redo surgery still is the treatment of choice for degenerated bioprosthesis. However, as far as elderly patients with concomitant comorbidities are concerned, the standard reoperation carries additional operative risks and, therefore, minimally invasive procedures must be prioritized.During the last ten years, transcatheter procedures in native valves have become a standard technique in several centers with excellent procedural and mid-term results. Similarly, implantation of transcatheter stent-valves within degenerated aortic and mitral bioprosthesis, the 'valve-in-valve' procedure (V-in-V), represents a valid alternative to redo surgery in patients with high-risk surgical profiles. New challenges for V-in-V are the transcatheter stent-valve deployment in hostile targets (stented bioprosthesis with externally mounted leaflets, stentless valves, small bioprostheses), and avoid complications as delayed atrial embolization of mitral implantation and V-in-V thrombosis. Moreover a continuous ameliorated design of the devices on the market and new transcatheter stent-valves are recently developed in order to improve the outcome and safety of V-in-V treatment. Expert commentary: We reviewed the clinical outcomes and the procedural details of published transcatheter aortic and mitral valve-in-valve series focusing, in particular, on data from the Valve-in-Valve International Data registry (VIVID), and we provide a practical guide for valve sizing and stent-valve positioning.

The majority of transcatheter aortic valve implantations, structural heart procedures and the newly developed transcatheter mitral valve repair and replacement are traditionally performed either through a transfemoral or a transapical access site, depending on the presence of severe peripheral vascular disease or anatomic limitations. The transapical approach, which carries specific advantages related to its antegrade nature and the short distance between the introduction site and the cardiac target, is traditionally performed through a left anterolateral mini-thoracotomy and requires rib retractors, soft tissue retractors and reinforced apical sutures to secure, at first, the left ventricular apex for the introduction of the stent-valve delivery systems and then to seal the access site at the end of the procedure. However, despite the advent of low-profile apical sheaths and newly designed delivery systems, the apical approach represents a challenge for the surgeon, as it has the risk of apical tear, life-threatening apical bleeding, myocardial damage, coronary damage and infections. Last but not least, the use of large-calibre stent-valve delivery systems and devices through standard mini-thoracotomies compromises any attempt to perform transapical transcatheter structural heart procedures entirely percutaneously, as happens with the transfemoral access site, or via a thoracoscopic or a miniaturised video-assisted percutaneous technique. During the past few years, prototypes of apical access and closure devices for transapical heart valve procedures have been developed and tested to make this standardised successful procedure easier. Some of them represent an important step towards the development of truly percutaneous transcatheter transapical heart valve procedures in the clinical setting.

Objectives The goal was to show the technical details, feasibility and clinical results of balloon-expandable stent valve implantation in the aortic position during conventional redo open-heart surgery in selected obese patients with a small aortic prosthesis and severe patient-prosthesis mismatch. Methods Two symptomatic overweight patients (body mass index of 31 and 38), each with a small aortic prosthesis (a 4-year-old, 21-mm Hancock II biological valve and a 29-year-old, 23-mm Duromedic mechanical valve), increased transvalvular gradients (59/31 and 74/44 mmHg) and a reduced indexed effective orifice area (0.50 and 0.43 cm 2 /m 2 ) underwent implantation of two 26-mm balloon-expandable Sapien 3 valves during standard on-pump redo valve surgery. Results Using full re-sternotomy, cardiopulmonary bypass and cardioplegic arrest, the two balloon-expandable stent valves were implanted under direct view using a standard aortotomy, after prosthesis removal and without annulus enlargement. Aortic cross-clamp times were 162 and 126 min; cardiopulmonary bypass times were 178 and 180 min; total surgical times were 360 and 318 min. At discharge, echocardiograms showed transvalvular peak and mean gradients of 13/9 and 23/13 mmHg and indexed effective orifice areas of 0.64 and 1.08 cm 2 /m 2 . The 3-month echocardiographic follow-up showed transvalvular peak and mean gradients of 18/9 and 19/11 mmHg and indexed effective orifice areas of 0.78 cm 2 /m 2 and 0.84 cm 2 /m 2 , with improved symptoms (New York Heart Association class 1). Conclusions Implantation of a balloon-expandable stent valve during redo aortic valve surgery is feasible in selected cases and prevents patient-prosthesis mismatch in obese patients without need for aortic annulus enlargement. Moreover, in the case of stent valve degeneration, this approach permits additional valve-in-valve procedures with large stent valves and prevents re-redo surgery.

Spatial regulation of secretory molecule release is a sophisticated mechanism used by the nervous system to control network development and finely tune the activity of each synapse. Great efforts have been made to develop techniques that mimic secretory molecule release with the aim of stimulating neurons as close as possible to physiological conditions. However, current techniques have poor spatial resolution or low flexibility. Here, we propose a novel approach to achieve focal and prolonged stimulation of neurons using optical tweezers and single microbeads functionalized with a secretory molecule, the neurotrophin brain-derived neurotrophic factor (BDNF). BDNF is a key regulator of neuronal development and plasticity. We show that single BDNF-coated microbeads can be extracted with optical tweezers from small reservoirs and positioned with submicrometric precision to specific sites on the dendrites of cultured hippocampal neurons. Localized contact of microbeads functionalized with BDNF, but not with bovine serum albumin (BSA), induced focal increase of calcium signaling in the stimulated dendrite, specific activation of the TrkB receptor pathway and influenced the development of growth cones. Remarkably, a single BDNF-coated bead localized on a dendrite was found to be enough for TrkB phosphorylation, an efficient and long-lasting activation of calcium signaling in the soma, and c-Fos signaling in the nucleus, comparable to bath stimulation conditions. These findings support the use of optical tweezer technology for long-term, localized stimulation of specific subcellular neuronal compartments.