An ex-vivo and in-vitro dynamic simulator for surgical and transcatheter mitral valve interventions.

PURPOSE: Minimally invasive mitral valve surgery (MIMVS) and transcatheter edge-to-edge repair (TEER) are complex procedures used to treat mitral valve (MV) pathologies, but with limited training opportunities available. To enable training, a realistic hemodynamic environment is needed. In this work we aimed to develop and validate a simulator that enables investigation of MV pathologies and their repair by MIMVS and TEER in a hemodynamic setting. METHODS: Different MVs were installed in the simulator, and pressure, flow, and transesophageal echocardiographic measurements were obtained. To confirm the simulator's physiological range, we first installed a biological prosthetic, a mechanical prosthetic, and a competent excised porcine MV. Subsequently, we inserted two porcine MVs-one with induced chordae tendineae rupture and the other with a dilated annulus, along with a patient-specific silicone valve extracted from echocardiography with bi-leaflet prolapse. Finally, TEER and MIMVS procedures were conducted by experts to repair the MVs. RESULTS: Systolic pressures, cardiac outputs, and regurgitations volumes (RVol) with competent MVs were 119 ± 1 mmHg, 4.78 ± 0.16 l min-1, and 5 ± 3 ml respectively, and thus within the physiological range. In contrast, the pathological MVs displayed increased RVols. MIMVS and TEER resulted in a decrease in RVols and mitigated the severity of mitral regurgitation. CONCLUSION: Ex-vivo modelling of MV pathologies and repair procedures using the described simulator realistically replicated physiological in-vivo conditions. Furthermore, we showed the feasibility of performing MIMVS and TEER at the simulator, also at patient-specific level, thus providing new clinical perspectives in terms of training modalities and personalized planning.

Surgical training of minimally invasive mitral valve repair on a patient-specific simulator improves surgical skills.

OBJECTIVES: Minimally invasive mitral valve repair (MVR) is considered one of the most challenging operations in cardiac surgery and requires much practice and experience. Simulation-based surgical training might be a method to support the learning process and help to flatten the steep learning curve of novices. The purpose of this study was to show the possible effects on learning of surgical training using a high-fidelity simulator with patient-specific mitral valve replicas. METHODS: Twenty-five participants were recruited to perform MVR on anatomically realistic valve models during different training sessions. After every session their performance was evaluated by a surgical expert regarding accuracy and duration for each step. A second blinded rater similarly assessed the performance after the study. Through repeated documentation of those parameters, their progress in learning was analysed, and gains in proficiency were evaluated. RESULTS: Participants showed significant performance enhancements in terms of both accuracy and time. Their surgical skills showed sizeable improvements after only 1 session. For example, the time to implant neo-chordae decreased by 24.64% (354 s-264 s, P < 0.001) and the time for annuloplasty by 4.01% (54 s-50 s, P = 0.165), whereas the number of irregular stitches for annuloplasty decreased from 52% to 24%.The significance of simulation-based surgical training as a tool for acquiring and training surgical skills was reviewed positively. CONCLUSIONS: The results of this study indicate that simulation-based surgical training is a valuable and effective method for learning reconstructive techniques of minimally invasive MVR and overall general dexterity.The novel learning and training options should be implemented in the surgical traineeship for systematic teaching of various surgical skills.

Octogenarian patients and laser-assisted lead extraction: Should we put a limit?

BACKGROUND: Transvenous laser lead extraction (TLE) for cardiac implantable electric devices (CIED) is a challenging procedure especially if performed in octogenarians. In this study we evaluated the safety and efficacy of transvenous laser lead extraction in elderly patients. METHODS: This is a retrospective study of octogenarian patients who underwent laser-assisted lead extraction (LLE) (GlideLight laser sheath, Philips, San Diego, USA). 270 Consecutive patients were included. Patients were divided into two groups. Octogenarian group and non-octogenarian group. The Data was gathered from patients treated between September 2013 and January 2020 and is retrospectively analyzed. RESULTS: Of 270 consecutive patients, 38 (14.0%) were 80 years old or more. The total number of the extracted leads was 556 among which 84(15.0%) from the Octogenarian group. From these leads were 155 single coil leads, 82 dual coil leads, 129 right ventricular pacing leads, 155 right atrial leads, and 35 left ventricular leads. In the Octogenarian group the number of removed leads was as follows: 13 single coil leads, 10 dual coil leads, 28 right ventricular pacing leads, 28 right atrial leads and 5 left ventricular leads. No mortality was recorded in the Octogenarian group. One patient in the YG suffered from a superior vena cava tear and one patient suffered from pulmonary embolism. CONCLUSION: In octogenarian laser assisted lead extraction patients is a safe and effective procedure. No increase in morbidity, mortality or perioperative complication could be recorded in this group. Age should not be a limiting factor to perform this procedure.

Comparative evaluation of three commercially available markerless depth sensors for close-range use in surgical simulation.

PURPOSE: Minimally invasive surgeries have restricted surgical ports, demanding a high skill level from the surgeon. Surgical simulation potentially reduces this steep learning curve and additionally provides quantitative feedback. Markerless depth sensors show great promise for quantification, but most such sensors are not designed for accurate reconstruction of complex anatomical forms in close-range. METHODS: This work compares three commercially available depth sensors, namely the Intel D405, D415, and the Stereolabs Zed-Mini in the range of 12-20 cm, for use in surgical simulation. Three environments are designed that closely mimic surgical simulation, comprising planar surfaces, rigid objects, and mitral valve models of silicone and realistic porcine tissue. The cameras are evaluated on Z-accuracy, temporal noise, fill rate, checker distance, point cloud comparisons, and visual inspection of surgical scenes, across several camera settings. RESULTS: The Intel cameras show sub-mm accuracy in most static environments. The D415 fails in reconstructing valve models, while the Zed-Mini provides lesser temporal noise and higher fill rate. The D405 could reconstruct anatomical structures like the mitral valve leaflet and a ring prosthesis, but performs poorly for reflective surfaces like surgical tools and thin structures like sutures. CONCLUSION: If a high temporal resolution is needed and lower spatial resolution is acceptable, the Zed-Mini is the best choice, whereas the Intel D405 is the most suited for close-range applications. The D405 shows potential for applications like deformable registration of surfaces, but is not yet suitable for applications like real-time tool tracking or surgical skill assessment.

Surgical Rehearsal for Mitral Valve Repair: Personalizing Surgical Simulation by 3D Printing.

PURPOSE: The goal of this study was to show possible effects of performing the actual procedure of mitral valve repair (MVR) on personalized silicone models 1 day before operation. DESCRIPTION: Based on preoperative 3-dimensional echocardiography recordings, flexible 3-dimensional replicas of the depicted pathologic mitral valves could be produced and used for a simulation of reconstructive techniques analogous to the upcoming MVR procedure. We integrated this step of personalized surgical planning into the clinical routine of 6 MVR cases with 3 different surgeons. This pilot study was assessed by evaluating questionnaires and by comparing isolated surgical steps with conventional MVRs. EVALUATION: This approach was considered a better preparation for MVRs with overall positive responses from the surgeons. Simulation helped reduce the time of initial inspection of the valve because of better understanding of the valve's pathomorphologic features. Annuloplasty benefited from preoperative sizing by reducing the number of sizing attempts. CONCLUSIONS: These initial findings suggest that simulation-based surgical planning can be implemented into patients' and physicians' clinical workflow as a major technologic advancement for future MVR preparation.

Case report of an S-ICD implantation for secondary prevention in a patient with complex congenital heart disease, dextrocardia, and situs solitus.

Background: Dextrocardia is a congenital anomaly in which the apex of the heart is abnormally located on the right side of the chest. Situs solitus describes viscera that are in the normal position, with the stomach on the left side. In these patients, implantation of transvenous implantable cardioverter-defibrillator (ICD) can be limited by anatomical abnormalities commonly associated with this condition. Case summary: We present the case of a young female patient with absent right atrioventricular connection, morphologically left systemic ventricle, muscular restrictive ventricular septal defect, and dextrocardia with situs solitus who was indicated for secondary prophylactic ICD implantation after resuscitation for polymorphic ventricular tachycardia. Due to a bilateral bidirectional Glenn anastomosis, transvenous access via the vena cava superior to the right ventricle could not be achieved. For this reason, we successfully implanted a subcutaneous ICD (S-ICD) with an individually optimized right parasternal electrode position. Potential complications of epimyocardial implantation via re-thoracotomy could thus be circumvented. Discussion: In patients with complex congenital heart disease, the S-ICD is an effective method of preventing sudden cardiac death. Our case report demonstrates the feasibility of left S-ICD implantation even in the presence of dextrocardia with situs solitus.

The GermAn Laser Lead Extraction RegistrY: GALLERY.

AIMS: The GermAn Laser Lead Extraction RegistrY: GALLERY is a retrospective, national multicentre registry, investigating the safety and efficacy of laser lead extraction procedures in Germany. METHODS AND RESULTS: Twenty-four German centres that are performing laser lead extraction have participated in the registry. All patients, treated with a laser lead extraction procedure between January 2013 and March 2017, were consecutively enrolled. Safety and efficacy of laser lead extraction were investigated. A total number of 2524 consecutive patients with 6117 leads were included into the registry. 5499 leads with a median lead dwell time of 96 (62-141) months were treated. The mean number of treated leads per patient was 2.18 ± 1.02. The clinical procedural success rate was 97.86% and the complete lead removal was observed in 94.85%. Additional extraction tools were used in 6.65% of cases. The rate of procedural failure was 2.14% with lead age ≥10 years being its only predictor. The overall complication rate was 4.32%, including 2.06% major and 2.26% minor complications. Procedure-related mortality was 0.55%. Female sex and the presence of abandoned leads were predictors for procedure-related complications. The all-cause in-hospital mortality was 3.56% with systemic infection being the strongest predictor, followed by age ≥75 years and chronic kidney disease. CONCLUSION: In the GALLERY, a high success- and low procedure-related complication rates have been demonstrated. In multivariate analysis, female sex and the presence of abandoned leads were predictors for procedure-related complications, while the presence of systemic infection, age ≥75 years, and chronic kidney disease were independent predictors for all-cause mortality.

Mutually Improved Endoscopic Image Synthesis and Landmark Detection in Unpaired Image-to-Image Translation.

The CycleGAN framework allows for unsupervised image-to-image translation of unpaired data. In a scenario of surgical training on a physical surgical simulator, this method can be used to transform endoscopic images of phantoms into images which more closely resemble the intra-operative appearance of the same surgical target structure. This can be viewed as a novel augmented reality approach, which we coined Hyperrealism in previous work. In this use case, it is of paramount importance to display objects like needles, sutures or instruments consistent in both domains while altering the style to a more tissue-like appearance. Segmentation of these objects would allow for a direct transfer, however, contouring of these, partly tiny and thin foreground objects is cumbersome and perhaps inaccurate. Instead, we propose to use landmark detection on the points when sutures pass into the tissue. This objective is directly incorporated into a CycleGAN framework by treating the performance of pre-trained detector models as an additional optimization goal. We show that a task defined on these sparse landmark labels improves consistency of synthesis by the generator network in both domains. Comparing a baseline CycleGAN architecture to our proposed extension (DetCycleGAN), mean precision (PPV) improved by +61.32, mean sensitivity (TPR) by +37.91, and mean F1 score by +0.4743. Furthermore, it could be shown that by dataset fusion, generated intra-operative images can be leveraged as additional training data for the detection network itself.

Point detection through multi-instance deep heatmap regression for sutures in endoscopy.

PURPOSE: Mitral valve repair is a complex minimally invasive surgery of the heart valve. In this context, suture detection from endoscopic images is a highly relevant task that provides quantitative information to analyse suturing patterns, assess prosthetic configurations and produce augmented reality visualisations. Facial or anatomical landmark detection tasks typically contain a fixed number of landmarks, and use regression or fixed heatmap-based approaches to localize the landmarks. However in endoscopy, there are a varying number of sutures in every image, and the sutures may occur at any location in the annulus, as they are not semantically unique. METHOD: In this work, we formulate the suture detection task as a multi-instance deep heatmap regression problem, to identify entry and exit points of sutures. We extend our previous work, and introduce the novel use of a 2D Gaussian layer followed by a differentiable 2D spatial Soft-Argmax layer to function as a local non-maximum suppression. RESULTS: We present extensive experiments with multiple heatmap distribution functions and two variants of the proposed model. In the intra-operative domain, Variant 1 showed a mean [Formula: see text] of [Formula: see text] over the baseline. Similarly, in the simulator domain, Variant 1 showed a mean [Formula: see text] of [Formula: see text] over the baseline. CONCLUSION: The proposed model shows an improvement over the baseline in the intra-operative and the simulator domains. The data is made publicly available within the scope of the MICCAI AdaptOR2021 Challenge https://adaptor2021.github.io/ , and the code at https://github.com/Cardio-AI/suture-detection-pytorch/ .

Risk of venous occlusion after lead laser extraction preventing future lead implantation.

BACKGROUND: Lead laser extraction is a well-established method for removing unwanted leads with low morbidity and mortality. OBJECTIVE: In this observational study, we documented our experience with venous occlusion after lead laser extraction. METHODS: Retrospective data of patients who underwent lead laser extraction between May 2010 and August 2018 was analyzed. Two subgroups of patients were identified. First group represented patients after lead laser extraction who suffered postoperative venous occlusion. Second group represents patients after lead laser extraction, who has documented patent venous access after lead laser extraction. RESULTS: 219 patients underwent percutaneous laser lead extraction. The mean age of patients was 65 ± 14 years. Of these patients, 74% were male. The Most common indication for extraction was Nonfunctional lead (45.2%, n = 99) followed by pocket infection with 33.8% and endocarditis (17.3%). A total number of 447 leads underwent laser extraction. In 7.8% of the patients, lead extraction was partially successful and lead extraction was not successful in only 2.3% of the patients. Only 13 patients developed a documented venous occlusion postoperatively and 26 patients has documented absence of venous occlusion, of whom 17 were under oral anticoagulation. CONCLUSION: Lead laser extraction may lead to venous occlusion, which is mostly asymptomatic but it prevents future lead implantation. The use of oral anticoagulant may prevent postoperative venous occlusion.

The use of laser lead extraction sheath in the presence of supra-cardiac occlusion of the central veins for cardiac implantable electronic device lead upgrade or revision.

BACKGROUND: The implantation of cardiac implantable electronic devices (CIED) has increased in the last decades with improvement in the quality of life of patients with cardiac rhythm disorders. The presence of bilateral subclavian, innominate or superior vena cava obstruction is a major limitation to device revision and/or upgrade. METHODS AND MATERIAL: This is retrospective study of patients who underwent laser-assisted lead extraction (LLE) (GlideLight laser sheath, Spectranetics Corporation, Colorado Springs, USA) with lead revision or upgrade using the laser sheath as a guide rail. Patients with known occlusion, severe stenosis or functional obstruction of the venous access vessels with indwelling leads were included in this study. RESULTS: 106 patients underwent percutaneous LLE with lead revision and/or upgrade. Preoperative known complete occlusion or severe stenosis of access veins was present in 23 patients (21.5%). More patients with implantable cardioverter-defibrillator (ICD) underwent LLE (64.1%) than patients with CRT-Ds (24.5%) and pacemaker patients (11.3%). In total 172 leads were extracted: 79 (45.9%) single-coil defibrillator leads, 35 (20.3%) dual-coil defibrillator leads, 31 (18.0%) right atrial leads, 24 (13.9%) right ventricular leads and three (1.7%) malfunctional coronary sinus left ventricular pacing leads. The mean age of leads was 99.2±65.6 months. The implantation of new leads after crossing the venous stenosis/obstruction was successful in 98 (92.4%) cases. Postoperative complications were pocket hematoma in two cases and wound infection in one case. No peri-operative and no immediate postoperative death was recorded. One intraoperative superior vena cava tear was treated by immediate thoracotomy and surgical repair. CONCLUSION: In a single-center study on LLE in the presence of supra-cardiac occlusion of the central veins for CIED lead upgrade and revision we could demonstrate a low procedural complication rate with no procedural deaths. Most of the leads could be completely extracted to revise or upgrade the system. Our study showed a low complication rate, with acceptable mortality rates.

Mitral valve flattening and parameter mapping for patient-specific valve diagnosis.

PURPOSE: Intensive planning and analysis from echocardiography are a crucial step before reconstructive surgeries are applied to malfunctioning mitral valves. Volume visualizations of echocardiographic data are often used in clinical routine. However, they lack a clear visualization of the crucial factors for decision making. METHODS: We build upon patient-specific mitral valve surface models segmented from echocardiography that represent the valve's geometry, but suffer from self-occlusions due to complex 3D shape. We transfer these to 2D maps by unfolding their geometry, resulting in a novel 2D representation that maintains anatomical resemblance to the 3D geometry. It can be visualized together with color mappings and presented to physicians to diagnose the pathology in one gaze without the need for further scene interaction. Furthermore, it facilitates the computation of a Pathology Score, which can be used for diagnosis support. RESULTS: Quality and effectiveness of the proposed methods were evaluated through a user survey conducted with domain experts. We assessed pathology detection accuracy using 3D valve models in comparison with the novel visualizations. Classification accuracy increased by 5.3% across all tested valves and by 10.0% for prolapsed valves. Further, the participants' understanding of the relation between 3D and 2D views was evaluated. The Pathology Score is found to have potential to support discriminating pathologic valves from normal valves. CONCLUSIONS: In summary, our survey shows that pathology detection can be improved in comparison with simple 3D surface visualizations of the mitral valve. The correspondence between the 2D and 3D representations is comprehensible, and color-coded pathophysiological magnitudes further support the clinical assessment.

Temporal Views of Flattened Mitral Valve Geometries.

The mitral valve, one of the four valves in the human heart, controls the bloodflow between the left atrium and ventricle and may suffer from various pathologies. Malfunctioning valves can be treated by reconstructive surgeries, which have to be carefully planned and evaluated. While current research focuses on the modeling and segmentation of the valve, we base our work on existing segmentations of patient-specific mitral valves, that are also time-resolved ( 3D+t) over the cardiac cycle. The interpretation of the data can be ambiguous, due to the complex surface of the valve and multiple time steps. We therefore propose a software prototype to analyze such 3D+t data, by extracting pathophysiological parameters and presenting them via dimensionally reduced visualizations. For this, we rely on an existing algorithm to unroll the convoluted valve surface towards a flattened 2D representation. In this paper, we show that the 3D+t data can be transferred to 3D or 2D representations in a way that allows the domain expert to faithfully grasp important aspects of the cardiac cycle. In this course, we not only consider common pathophysiological parameters, but also introduce new observations that are derived from landmarks within the segmentation model. Our analysis techniques were developed in collaboration with domain experts and a survey showed that the insights have the potential to support mitral valve diagnosis and the comparison of the pre- and post-operative condition of a patient.

Flexible and comprehensive patient-specific mitral valve silicone models with chordae tendineae made from 3D-printable molds.

PURPOSE: Given the multitude of challenges surgeons face during mitral valve repair surgery, they should have a high confidence in handling of instruments and in the application of surgical techniques before they enter the operating room. Unfortunately, opportunities for surgical training of minimally invasive repair are very limited, leading to a situation where most surgeons undergo a steep learning curve while operating the first patients. METHODS: In order to provide a realistic tool for surgical training, a commercial simulator was augmented by flexible patient-specific mitral valve replica. In an elaborated production pipeline, finalized after many optimization cycles, models were segmented from 3D ultrasound and then 3D-printable molds were computed automatically and printed in rigid material, the lower part being water-soluble. After silicone injection, the silicone model was dissolved from the mold and anchored in the simulator. RESULTS: To our knowledge, our models are the first to comprise the full mitral valve apparatus, i.e., the annulus, leaflets, chordae tendineae and papillary muscles. Nine different valve molds were automatically created according to the proposed workflow (seven prolapsed valves and two valves with functional mitral insufficiency). From these mold geometries, 16 replica were manufactured. A material test revealed that EcoflexTM 00-30 is the most suitable material for leaflet-mimicking tissue out of seven mixtures. Production time was around 36 h per valve. Twelve surgeons performed various surgical techniques, e.g., annuloplasty, neo-chordae implantation, triangular leaflet resection, and assessed the realism of the valves very positively. CONCLUSION: The standardized production process guarantees a high anatomical recapitulation of the silicone valves to the segmented models and the ultrasound data. Models are of unprecedented quality and maintain a high realism during haptic interaction with instruments and suture material.

Epicardial pacemaker as a bridge for pacemaker-dependent patients undergoing explantation of infected cardiac implantable electronic devices.

BACKGROUND AND AIM OF THE STUDY: Cardiac implantable electronic device (CIED) implantation is associated with an increase in CIED infection. For pacemaker-dependent patients, temporary pacemaker leads are implanted until infection remission, which allows new CIED implantation. We compared the outcome of pacemaker-dependent patients with infected CIED based on whether a combined single procedure of epicardial pacemaker implantation with system extraction or a temporary transjugular pacemaker implantation with interval system implantation was performed. METHODS: This retrospective study included pacemaker-dependent patients with CIED infection who were divided into two groups: the Tempo and Epi groups. The Tempo group received temporary transvenous pacemaker connected to an external pulse generator. After infection remission, a new permanent pacemaker was implanted, and the temporary pacemaker leads were removed. The Epi group received implantable epicardial right-ventricular pacemaker through infrasternal inferior pericardiotomy, and a permanent pulse generator was implanted through the same incision between the subcutaneous tissue and abdominal fascia. RESULTS: Sixty-six patients were included. Forty-two patients with epicardial pacemakers were discharged after 9.5 ± 8.8 days without infection of the newly implanted epicardial pacemaker. Patients with temporary transjugular pacemaker lead were discharged 23 ± 15 days after receiving permanent pacemakers. No serious complications were recorded in the Epi group. CONCLUSIONS: CIED infections in pacemaker-dependent patients can be treated through epicardial pacemaker implantation that allows early patient mobility and reduces hospital stay with no risk of epicardial pacemaker infection. Epicardial pacemakers can be used as a bridge until permanent intravenous CIED is implanted or as a replacement for permeant intravenous CIED.

Replicated mitral valve models from real patients offer training opportunities for minimally invasive mitral valve repair.

OBJECTIVES: Minimally invasive mitral valve repair is considered a challenging procedure. Mastering the necessary skills takes years of training and clinical experience. To date, reconstructive surgery is performed mainly by a few surgeons with a strong track record, whereas trainees have only limited opportunities to practise. METHODS: A high-fidelity training simulator was equipped with novel silicone replicas of patient-specific mitral valves containing all of the anatomical components of the valve. The goal of this system was to aid members of the surgical community to overcome the steep learning curve. RESULTS: Twelve surgeons (5 experts and 7 surgical resident trainees) performed a minimally invasive mitral valve repair procedure on these models and assessed the usefulness for different applications. The trainees found the main application to be general surgical training and education for mitral valve repair, whereas the experts found the main benefit to be rehearsal for a specific patient. The skills of the trainees were improved in only a single session. The valve models placed in a water solution showed a high echogenicity. CONCLUSIONS: Preoperative patient-specific simulation could improve the safety and effectiveness of mitral valve repair in the hands of a larger number of surgeons. Because the system is based on a quantitative segmentation of the anatomy of the mitral valve, it offers young surgeons training in general dexterity and also provides an exact numerical quantitative assessment of valvular geometry. This system can be used to educate surgeons to strive for and achieve well-defined and measurable surgical changes to the anatomy of the valve and to achieve the desired functional results.

Computer-based comparison of different methods for selecting mitral annuloplasty ring size.

BACKGROUND: Ring sizing for mitral valve annuloplasty is conventionally done intraoperatively using specific 'sizer' instruments, which are placed onto the valve tissue. This approach is barely reproducible since different sizing strategies have been established among surgeons. The goal of this study is to virtually apply different sizing methods on the basis of pre-repair echocardiography to find out basic differences between sizing strategies. METHODS: In three-dimensional echocardiographs of 43 patients, the mitral annulus and the contour of the anterior mitral leaflet were segmented using MITK Mitralyzer software. Similarly, three-dimensional virtual models of Carpentier-Edwards Physio II annuloplasty rings and their corresponding sizers were interactively generated from computer tomography images. For each patient, the matching annuloplasty ring was selected repeatedly according to popular sizing strategies, such as the height of anterior mitral leaflet, the intercommissural distance and the surface area of anterior mitral leaflet. The areas of the selected rings were considered as the neo-surface area of the mitral annulus after implantation. RESULTS: The sizing of the mitral valve according to the height of anterior mitral leaflet (mean ring size = 29.9 ± 3.90), intercommissural distance (mean ring size = 37.5 ± 1.92) or surface area of anterior mitral leaflet (mean ring size = 32.7 ± 3.3) led to significantly different measurements (p ≤ 0.01). In contrary to intercommissural distance, height and surface area of the anterior mitral leaflet exhibited significant variations between the patients (p ≤ 0.01). The sizing according to the height of anterior mitral leaflet led to the maximal reduction of the mitral annulus surface area followed by the sizing according to the surface area of anterior mitral leaflet and finally by the intercommissural distance. CONCLUSIONS: This novel comprehensive computer-based analysis reveals that the surveyed sizing methods led to the selection of significantly different annuloplasty rings and therefore underscore the ambiguity of routinely applied annuloplasty sizing strategies.

Inverse remodelling of K2P3.1 K+ channel expression and action potential duration in left ventricular dysfunction and atrial fibrillation: implications for patient-specific antiarrhythmic drug therapy.

AIMS: Atrial fibrillation (AF) prevalence increases with advanced stages of left ventricular (LV) dysfunction. Remote proarrhythmic effects of ventricular dysfunction on atrial electrophysiology remain incompletely understood. We hypothesized that repolarizing K2P3.1 K+ channels, previously implicated in AF pathophysiology, may contribute to shaping the atrial action potential (AP), forming a specific electrical substrate with LV dysfunction that might represent a target for personalized antiarrhythmic therapy. METHODS AND RESULTS: A total of 175 patients exhibiting different stages of LV dysfunction were included. Ion channel expression was quantified by real-time polymerase chain reaction and Western blot. Membrane currents and APs were recorded from atrial cardiomyocytes using the patch-clamp technique. Severely reduced LV function was associated with decreased atrial K2P3.1 expression in sinus rhythm patients. In contrast, chronic (c)AF resulted in increased K2P3.1 levels, but paroxysmal (p)AF was not linked to significant K2P3.1 remodelling. LV dysfunction-related suppression of K2P3.1 currents prolonged atrial AP duration (APD) compared with patients with preserved LV function. In individuals with concomitant LV dysfunction and cAF, APD was determined by LV dysfunction-associated prolongation and by cAF-dependent shortening, respectively, consistent with changes in K2P3.1 abundance. K2P3.1 inhibition attenuated APD shortening in cAF patients irrespective of LV function, whereas in pAF subjects with severely reduced LV function, K2P3.1 blockade resulted in disproportionately high APD prolongation. CONCLUSION: LV dysfunction is associated with reduction of atrial K2P3.1 channel expression, while cAF leads to increased K2P3.1 abundance. Differential remodelling of K2P3.1 and APD provides a basis for patient-tailored antiarrhythmic strategies.

The geometrical effect of different annuloplasty rings on mitral valve annulus.

BACKGROUND: Different types of mitral annuloplasty rings are commercially available. The aim of this study was to investigate the effect of implantation of six types of annuloplasty rings on the geometry and dynamics of the mitral valve. METHODS: Three-dimensional echocardiography images of 42 patients were acquired to visualize the mitral valve annulus. Virtual representations of six commercially available annuloplasty rings were matched to anatomical mitral annuli of each patient according to anterolateral-posteromedial diameter. The virtual displacement of each annuloplasty ring after the implantation was measured and compared with the other rings. RESULTS: Patients with severe mitral regurgitation had significantly dilated annuli according to anterolateral-posteromedial diameter, anterior-posterior diameter and to annulus circumference. Anterior and posterior heights of the mitral annuli and non-planarity angle showed no significant differences among different patients with different degree of mitral regurgitation. The ratio of anterior-posterior to anterolateral-posteromedial diameter was almost identical in all groups with identical annular shapes. The implantation of the Carpentier-Edwards Classic Annuloplasty Ring™ led to maximal displacement of mitral annulus, followed by the IM-Ring™, without a statistical significance. In contrary, the implantation of a MyxoETlogix Ring™ was associated with minimal displacement of mitral annulus throughout the groups, but without statistical significance. CONCLUSIONS: The implantation of different ring types in patients with different annuli shapes and dimensions did not lead to any significant change in the configuration of mitral annuli after the virtual implantation of the tested annuloplasty rings.

Intraoperative Quantitative Mitral Valve Analysis Using Optical Tracking Technology.

PURPOSE: Analysis of mitral valve morphology during reconstruction is routinely based on visual assessment and subjective, poorly reproducible measurements. We prove the feasibility of a new intraoperative system for quantitative mitral valve analysis. DESCRIPTION: The proposed computer-based assistance system enables accurate intraoperative localization of anatomic landmarks on the mitral valve apparatus using optical tracking technology. Measurement and visualization strategies were specifically developed and tailored for mitral valve operations. EVALUATION: The feasibility of intraoperative quantitative measurements was successfully shown for 9 patients. Precise geometric descriptions of the valve were obtained and adequately visualized, providing valuable decision support during the intervention. The mean annular area obtained from the intraoperative measurements was 736 ± 266 mm(2), in good agreement with the mean area of the implanted prosthetic rings of 617 ± 124 mm(2), which are slightly smaller due to annular downsizing. Comparison with preoperative three-dimensional echocardiography revealed differences between the beating heart, with transverse and septolateral annular diameters of 40.6 ± 15.4 mm and 41.2 ± 8.2 mm, and the intraoperative cardioplegic condition, with corresponding diameters of 34.3 ± 6.9 mm and 27.4 ± 5.6 mm. CONCLUSIONS: Mitral valve analysis by optical tracking represents a unique technologic advance in intraoperative assessment, providing the surgeon with an extended quantitative perception of surgical target. This technology promotes a major philosophical change from an empirical procedure toward a quantitatively predictable modern reconstructive operation.