Leaflet Insertion Research Articles

4D ICE to guide transcatheter tricuspid edge-to-edge repair: intracardiac echocardiography compared to trans-esophageal echocardiography

Abstract Background Intracardiac 3D probes have been recently employed to guide structural heart interventions and the number of patients undergoing tricuspid transcatheter edge-to-edge repair (T-TEER) is growing rapidly. While transesophageal echocardiography (TEE) has traditionally been the preferred method for guiding TEER procedures, it may not be suitable for all patients. In contrast, intravascular cardiac echocardiography (ICE) offers several and appealing advantages by offering unique views that can aid in precise device deployment. Purpose This study aims to compare TEE and 4D-ICE performance in the context of percutaneous tricuspid valve interventions. Methods A cohort of ten patients undergoing T-TEER was prospectively enrolled. Each patient simultaneously received both TEE and 4D-ICE. The T-TEER procedure was divided into 8 steps (figure 1); at each step, TEE and 4D-ICE images were acquired and analyzed independently by two experienced echocardiographers. The steps were: Step 1: tricuspid valve anatomy assessment; Step 2: target lesion identification; Step 3: steering/valve approaching; Step 4: perpendicularity/trajectory; Step 5: clocking; Step 6: grasping; Step 7: leaflets insertion; Step 8: residual regurgitant jets. All the steps were re-evaluated each time an additional clip was necessary. Results A total of 10 patients were treated (mean age 76.7± 9.1; female 50%). Mean Triscore was 4.9±1.8; tricuspid regurgitation (TR) was severe (or more) in all cases. TR etiology was atrial in 9/10 and primary in 1/10 patients. Triclip and Pascal were used in 4 and 6 patients, respectively. 8/10 patients received two or more devices, whereas one device was used in 2/10 patients. Mean procedural time was 95’. Residual TR was mild in 7/10 cases, mild to moderate in 3/10. The morphology of the valve (Step 1) was concordant to TEE in 8 cases (80%); the same target lesion (Step 2) was identified in all cases; Step 3 was feasible in 10 ICE vs 9 TEE ; perpendicularity/trajectory (Step 4) was similarly achieved; Clocking (Step 5) using 4D-ICE was feasible in 10/10 cases with respect to 3D-MPR from mid-esophageal view (7/10) and in trans-gastric views (7/10). Grasping (Step 6) was achieved with 4D-ICE and without TEE in 3/10 cases due to better image quality. Leaflet insertion of the septal leaflet was better evaluated with 4D ICE than with TEE, due to 3 cases of shadowing of the septal leaflet caused by anterior structures (aorta and interatrial septum); lateral (posterior or anterior) leaflets insertion was comparable. Finally, quantification of residual jets (Step 8) was similar. Conclusions In our case series, 4D-ICE was successfully utilized in all patients, offering, in some cases, superior visualization of grasping and leaflet insertion during T-TEER procedure. 4D-ICE proves to be a viable alternative to TEE and can serve as fundamental complementary tool for patients with poor TEE acoustic windows. Step by Step analysis

Indications and outcomes of the MitraClip G4 device with controlled gripper actuation system.

The MitraClip G4 device has controlled gripper actuation (CGA) system, which allows the anterior and posterior grippers operate separately in transcatheter edge-to-edge repair (TEER). We investigated the indications and outcomes of the use of CGA system during TEER for significant mitral regurgitation (MR). We reviewed 158 patients undergoing TEER with MitraClip G4 from September 2020 to July 2023. The CGA indications were: (1) for grasping and (2) for leaflet insertion confirmation. Leaflet grasping was completed with CGA in 18 patients (11 and 7 patients for grasping and leaflet insertion confirmation, respectively). Patients with flail leaflets or coaptation gap more frequently required CGA, indicating more complex mitral valve anatomy. The procedural success and adverse event rates (death, leaflet tear and single leaflet device attachment) were not different between the CGA and non-CGA groups. In patients requiring CGA, single leaflet device attachment was observed in 1 patient and leaflet tear in 1 patient during follow-up. In these two cases, CGA was required for grasping, and the clip was moved over a large distance (6.5 and 12.4mm, respectively). In patients who had undergone CGA for confirmation, no device-related adverse event or MR recurrence was noted. In patients with complex mitral valve anatomy, CGA may be a safe and effective method for confirming leaflet insertion. It should be noted that when using CGA for leaflet grasping, especially when the clip is moved significantly, attention should be paid to leaflet adverse events.

Coaptation Reserve Predicts Optimal Reduction in Mitral Regurgitation and Long-Term Survival With Transcatheter Edge-to-Edge Repair.

Although transcatheter edge-to-edge repair (TEER) is effective and safe, there is a need for better prediction of optimal outcomes. We aimed to determine predictors of optimal reduction in mitral regurgitation (MR) and survival with TEER. We examined mitral anatomy and its change with TEER on outcomes in 183 patients (age, 82 [77-87] years; 53% women). Coaptation reserve was measured as the distance of continuous apposition of the A2 and P2 leaflet segments in 2-dimensional apical long-axis imaging at the site of the predominant jet of MR. Augmentation in coaptation was measured as the total amount of leaflet insertion. Addressable coaptation area was calculated using the physical boundaries of the TEER device. Coaptation reserve, its augmentation, and addressable coaptation area were strong predictors of MR reduction (all P<0.001), as well as heart failure hospitalization and death. For patients with either mild or no residual MR, median values for coaptation reserve, its augmentation, and addressable coaptation area were 3.7 (2.8-4.5) mm, 7.3 (5.2-9.5) mm, and 59.0 (48.0-71.8) mm2, respectively. Receiver operating characteristic analyses determined the best values for optimal MR reduction as a coaptation reserve of >3.0 mm (P<0.001), addressable coaptation area of ≥52 mm2 (P<0.001), and coaptation augmentation of ≥4.7 mm (P<0.001). These values were associated with greater 2-year survival free of all-cause mortality and persisting even in analyses restricted to those with mild or no residual MR after TEER. Coaptation reserve and its augmentation are simple, independent parameters that predict optimal MR reduction and better survival in patients undergoing TEER. These findings may have implications for patient selection and expanded use of the therapy.

Alterations in Human Mitral Valve Mechanical Properties Secondary to Left Ventricular Remodeling: A Biaxial Mechanical Study.

Secondary mitral regurgitation occurs when a left ventricular problem causes leaking of the mitral valve. The altered left ventricular geometry changes the orientation of the subvalvular apparatus, thereby affecting the mechanical stress on the mitral valve. This in turn leads to active remodeling of the mitral valve, in order to compensate for the ventricular remodeling. In this study, a biomechanical analysis was performed on eight human mitral valves with secondary mitral regurgitation and ten healthy human mitral valves to better understand this pathophysiology and its effect on the mechanical properties of these tissues. Samples were obtained from the anterior and posterior leaflet and used for planar biaxial mechanical experiments. Uniaxial experiments were performed on four groups of mitral valve chords: anterior basal, anterior marginal, posterior basal and posterior marginal chords. The mechanical response of the mitral valve leaflets was fitted to the May-Newman and Yin constitutive model, whereas the material parameters of the third order Ogden model were determined for the chord samples. Next, stiffnesses calculated at low and high stress levels were statistically analyzed. Leaflet samples with secondary mitral regurgitation showed a small thickness increase and a change in anisotropy index compared to healthy control valves. Diseased leaflets were more compliant circumferentially and stiffer radially, resulting in anisotropic samples with the radial direction being stiffest. In addition, chord samples were slightly thicker and less stiff at high stress in secondary mitral regurgitation, when grouped per leaflet type and insertion region. These results confirm mechanical alterations due to the pathophysiological valvular changes caused by left ventricular remodeling. It is important that these changes in mechanical behavior are incorporated into computational models of the mitral valve.

Recurrent Mitral Regurgitation After MitraClip: Predictive Factors, Morphology, and Clinical Implication.

Recurrent mitral regurgitation (MR) following MitraClip has not been thoroughly investigated. We aimed to examine the predictive factors, morphology, and long-term outcome of recurrent MR after MitraClip. We assessed data from the Heart Failure Network Rhineland registry from August 2010 to October 2018. Competing risk analyses were performed using the Fine and Gray model to assess the risk of recurrent MR. Among 685 MitraClip patients with a reduction in MR to ≤2+, 61 patients developed recurrent MR within the first 12 months. Flail leaflet (hazard ratio, 3.68; P=0.002) and residual MR (MR grade 2+ versus ≤1+: hazard ratio, 2.56; P=0.03) were the predictors of recurrent MR in primary MR patients, while left atrial volume (per 10 mL increase: hazard ratio, 1.11; P<0.001) and residual MR (hazard ratio, 2.45; P=0.01) were independently associated with recurrent MR in secondary MR patients. In primary MR patients, loss of leaflet insertion or leaflet tear were the predominant morphologies with recurrent MR. In secondary MR patients, more than half of the patients with recurrent MR did not show any disorder of the clip or leaflets. Patients with recurrent MR were more likely to experience unplanned heart failure hospitalization or heart failure symptom with New York Heart Association scale III/IV (54.1% versus 37.8%; P=0.018) and undergo a repeat mitral valve intervention (9.8% versus 2.2%; P=0.005) during the follow-up. In the landmark survival analysis, patients with recurrent MR tended to have lower long-term survival (58.7% versus 83.9%; P=0.08) than patients without recurrent MR. Flail leaflet and residual MR were the predictors of recurrent MR in primary MR patients, while a larger left atrial volume and residual MR were associated with recurrent MR in secondary MR patients, which may be associated with long-term clinical outcomes of patients after MitraClip.

Beating heart implantation of transventricular artificial cordae: How can access site selection and leaflet insertion improve mitral regurgitation correction?

NeoChord-DS1000-System (NC) and The Harpoon-Mitral-Repair-System (H-MRS) are two trans-apical chordal implantation devices developed for the treatment of degenerative mitral valve (MV) regurgitation (DMR) either if as Fibroelastic-Deficiency (FED), Forma-Frusta (FF), or Barlow (B) presentation. The aim of this study is to evaluate some of the advantages and disadvantages of these two different devices by performing numerical simulation analyses focused on different transventricular access sites in all subsets of DMR presentations. By applying a novel approach for the development of patient-specific MV domains we worked out a set of numerical simulations of the artificial chordae implantation. Different leaflet insertions and ventricle access sites were investigated, and resulting contact-area (CA), tensioning-forces (F) and leaflet's stress (LS) were calculated. The analyses showed that: i) NC-approach maintains low LS when performed with a posterior access site and optimizes the overlap between the leaflets at the systolic peak; ii) H-MRS-system presents better results in case of a more anterior ventricular entry site; however, for FED prolapse large variation of F and LS with respect to NC-approach are found; iii) an accidental contact between artificial sutures and the anterior leaflet may occur when valve function is restored through an excessive anterior access site. Present findings set light on specific technical aspects of transapical off-pump chords implantation, either performed with NC and H-MRS systems and highlight the advantages and disadvantages proper to the two devices. Our study also paves the basis for a systematic application of computational methodology, in order to plan a patient-specific mini-invasive approach thus maximizing the outcomes.

Management and Outcome of FailedPercutaneous Edge-to-Edge MitralValvePlasty: Insight From an International Registry.

This study evaluated the incidence, management, and outcome of patients who experienced MitraClip (Abbott Vascular) failure secondary to loss of leaflet insertion (LLI), single leaflet detachment (SLD), or embolization. Transcatheter edge-to-edge repair with MitraClip is an established therapy for the treatment of mitral regurgitation (MR), but no data exist regarding the prevalence and outcome according to the mode of clip failure. Between January 2009 and December 2020, we retrospectively screened 4,294 procedures of MitraClip performed in 19 centers. LLI was defined as damage to the leaflet where the MitraClip was attached, SLD as demonstration of complete separation between the device and a single leaflet tissue, and clip embolization as loss of contact between MitraClip and both leaflets. A total of 147 cases of MitraClip failure were detected (overall incidence=3.5%), and these were secondary to LLI or SLD in 47 (31.9%) and 99 (67.3%) cases, respectively, whereas in 1 (0.8%) case clip embolization was observed. MitraClip failure occurred in 67 (45.5%) patients with functional MR, in 64 (43.5%) patients with degenerative MR, and 16 (10.8%) with mixed etiology. Although the majority of MitraClip failures were detected before discharge (47 intraprocedural and 42 in the hospital), up to 39.5% of cases were diagnosed at follow-up. In total, 80 (54.4%) subjects underwent a redo procedure, either percutaneously with MitraClip (n=51, 34.7%) or surgically (n=36, 24.5%) including 4 cases of surgical conversion of the index procedure and 7 cases of bailout surgery after unsuccessful redo MitraClip. After a median follow-up of 163days (IQR: 22-720days), 50 (43.9%) subjects presented moderate to severe MR, and 43 (29.3%) patients died. An up-front redo MitraClip strategy was associated with a trend toward a reduced rate of death at follow-up vs surgical or conservative management (P=0.067), whereas postprocedural acute kidney injury, age, and moderate to severe tricuspid regurgitation were independent predictors of death. MitraClip failure secondary to LLI and SLD is not a rare phenomenon and may occur during and also beyond hospitalization. Redo MitraClip strategy demonstrates a trend toward a reduced risk of death compared with bailout surgery and conservative management. A third of those patients remained with more than moderate MR and had substantial mortality at the intermediate-term follow-up.

Impact of Anchor Location on Mitral Neochordae Forces: An In Vitro Study

PurposeThis study examined changes in force distribution between the neochordae corresponding to different ventricular anchor locations. DescriptionSeven porcine mitral valves were mounted in a left heart simulator. Neochordae (expanded polytetrafluoroethylene) originated from either a simulated left ventricular apex, papillary muscle base, or papillary muscle tip location. The neochordae were attached at three sites along the P2 leaflet segment: P2Lateral; P2Center, and P2Medial. Mitral regurgitation was induced by cutting posterior leaflet P2 marginal chordae. The forces on each neochord required to restore normal mitral valve coaptation were quantified for different ventricular anchoring origins and leaflet insertion sites. EvaluationThe results showed that under both normotensive and hypertensive conditions, the force exerted was much higher at P2Center than either P2Lateral or P2Medial, independent of ventricular anchor location. Also, forces on both P2Lateral and P2Medial were not statistically different. ConclusionsArtificial neochordae treatment for all anchoring locations was effective in correcting induced mitral regurgitation. The P2 central neochordae had a significantly higher force than both lateral neochords under all conditions.

Incidence and standardised definitions of mitral valve leaflet adverse events after transcatheter mitral valve repair: the EXPAND study.

An independent panel of experts reviewed all investigator-reported cases of mitral valve leaflet adverse events (LAE) after MitraClip NTR/XTR in the EXPAND study. We aimed to report the findings of the expert panel and standardise definitions for LAE. Standard definitions for different types of LAE were formulated and events adjudicated after detailed review by the expert panel. Enrolling centres reported LAE in 35 cases, 11 leaflet injuries (9 tears, 2 perforations) and 24 single leaflet device attachment (SLDA). The panel confirmed LAE in 20 cases (2.0% incidence), 18 patients had SLDA and 4 had leaflet injury (2 cases had both SLDA and injury). Leaflet injury occurred during device implant and resulted in surgical valve replacement or death. SLDA-alone events were identified during implant (n=2), pre-discharge (n=7) or at 30 days of follow-up (n=7) and were resolved (≤2+ residual MR) with additional clips in 75% of cases. Mitral valve repair with MitraClip NTR/XTR is safe. The rate of LAE is lower than previously reported using older-generation devices. The proposed definitions and findings will help to differentiate leaflet injury from inadequate leaflet insertion and SLDA and provide guidance for consistent diagnosis of LAE post MitraClip implantation.

Risk factors and etiology of recurrent mitral regurgitation after edge-to-edge mitral valve repair

Abstract Background Recurrent MR has been associated with poor prognosis after transcatheter mitral valve repair (TMVR) with the MitraClip system. However, little is known about risk factors and etiology of recurrent mitral regurgitation (MR) after transcatheter edge-to-edge mitral repair with the MitraClip system. Methods Among consecutive patients who underwent MitraClip for MR from January 2011 to March 2019, we identified 240 patients who had MR ≤2+ at discharge and follow-up echocardiography within three years after the procedure. Recurrent MR was defined as MR ≥3+ during the follow-up period. To investigate the risk factors for recurrent MR, we conducted a Cox proportional hazard model. Results During the follow-up period (median 491 days), 38 patients (15.8%) had recurrent MR (≥3+). The most frequent etiology of recurrent MR was degenerative (n=20, 52.6%), including single leaflet detachment (n=2, 5.3%), loss of leaflet insertion (n=11, 28.9%), and leaflet tear or prolapse (n=7, 18.4%), followed by functional MR (n=18, 47.4%). The risk factors for recurrent MR were greater LV end-diastolic volume (adjusted-HR 1.01, 95% CI 1.00–1.02, p=0.03), higher LV ejection fraction (LVEF) (adjusted-HR 1.05, 95% CI 1.01–1.08, p=0.005), and moderate MR upon discharge (adjusted-HR 2.98, 95% CI 1.50–5.95, p=0.002).After stratification according to the etiology of MR, the association of LVEF was more pronounced in patients with degenerative MR (adjusted-HR 1.07, 95% CI 1.02–1.12, p=0.003), while the association of moderate MR upon discharge was more pronounced in patients with functional MR (adjusted-HR 5.02, 95% CI 1.95–12.8, p&amp;lt;0.001). Furthermore, patients with recurrent MR had an increased antero-posterior annulus diameter regardless of the baseline etiology of the MR. Conclusions Greater LV volume, higher LVEF, and moderate MR at discharge were associated with an increased risk of recurrent MR after the MitraClip procedure. A significant increase of the annulus diameter was observed regardless of the baseline etiology of the MR. Etiology of recurrent MR Funding Acknowledgement Type of funding source: None

In-Vitro Assessment of the Effects of Transcatheter Aortic Valve Leaflet Design on Neo-Sinus Geometry and Flow

Transcatheter aortic valve (TAV) leaflet thrombosis is a clinical risk with potentially fatal consequences. Studies have identified neo-sinus flow stasis as a cause of leaflet thrombosis. Flow stasis is influenced by the TAV leaflets, which affect the local fluid dynamics in the aortic sinus and neo-sinus. This study evaluated the effects of TAV leaflet features on the neo-sinus flow as a measure of leaflet thrombosis risk. Five TAVs of varied leaflet length and insertion height were tested in a simulator. Hydrodynamics and leaflet kinematics through en-phase imaging were quantified. Velocity fields were assessed using high-speed particle image velocimetry. Regions of flow stasis and particle residence times (PRTs) were quantified. TAVs with shorter leaflet length exhibited larger orifice areas and lower transvalvular pressure gradients. Shorter leaflet length and increased leaflet insertion TAVs additionally exhibited lower neo-sinus PRTs (0.44 ± 0.21 vs 2.83 ± 0.48 cycles, p<0.05) and higher neo-sinus peak velocities (0.15 ± 0.009 vs 0.07 ± 0.005m/s, p<0.05) than TAVs with longer leaflet length and lower leaflet insertion. The average neo-sinus volume positively correlated with PRT(r=0.810, p<0.001), and extent of flow stasis (r=0.682, p<0.05). These results suggest that a small neo-sinus volume may reduce flow stagnation and particle residence, potentially reducing the risk of leaflet thrombosis. We propose that leaflet design features might be proactively controlled in the design of future transcatheter aortic valves.

Deep Sedation in a Patient Undergoing Transfemoral Tricuspid Valve Repair Using the PASCAL System

A 70-year-old man with severe tricuspid regurgitation and large coaptation gap (0.8 cm) was referred to transfemoral valve repair using the PASCAL system. The procedure was successful in reducing tricuspid regurgitation. The PASCAL device facilitated maximum leaflet insertion and to span large coaptation gap in severe tricuspid regurgitation without ventilation maneuvers under general anesthesia. (Level of Difficulty: Intermediate.)

4-Dimensional Intracardiac Echocardiography in Transcatheter Tricuspid Valve Repair With the MitraClip System

Transcatheter tricuspid valve repair (TTVr) using the MitraClip system (Abbott Structural Heart, Santa Clara, California) has demonstrated safety and efficacy ([1][1]). Procedural success, which consists of optimal leaflet insertion and reduction in tricuspid regurgitation (TR), is predictive of

Catheter Ablation of ArrhythmiasOriginating Fromthe LeftVentricularOutflow Tract.

The left ventricular outflow tract (LVOT) is a frequent source of arrhythmias in patients with and without structural heart disease. An understanding of the anatomic relationship between the aortic valvar leaflets and their supporting sinuses, coronary vessels, pulmonary arterial root, right ventricular outflow tract, and LVOT is essential for successful treatment of arrhythmias arising from this region. The juxtaposition of aortic valvar leaflet insertion into the aortic root and the crescents of myocardial tissue incorporated within the aortic sinuses of Valsalva has implications for mapping and ablation above and below the aortic valve leaflets. The presence of epicardial fat, coronary arteries, and prominent myocardium in the anteroseptal aspect of the LVOT can present unique challenges for targeting LV summit and intramural ventricular arrhythmias. Advances in ablation techniques that achieve deeper transmural lesions, combined with the knowledge of the complex LVOT anatomy and its adjoining structures, have increased success rates in targeting challenging LVOT arrhythmias.

Decellularized mitral valve in a long-term sheep model.

The objective of this study was to evaluate surgical handling, in vivo hemodynamic performance and morphological characteristics of decellularized mitral valves (DMVs) in a long-term sheep model. Ovine mitral valves were decellularized using detergents and β-mercaptoethanol. Orthotopic implantations were performed in 6-month-old sheep (41.3 ± 1.2 kg, n = 11) without annulus reinforcement. Commercially available stented porcine aortic valves [biological mitral valve (BMV), n = 3] were implanted conventionally and used as controls. Valve function was evaluated by transoesophageal echocardiography and explants were investigated by a routine bright field microscopy and immunofluorescent histology. During implantation, 2 DMVs required cleft closure of the anterior leaflet. All valves were competent on water test and early postoperative transoesophageal echocardiography. Six animals (DMV, n = 4; BMV, n = 2) survived 12 months. Six animals died within the first 4 months due to valve-related complications. At 12 months, transoesophageal echocardiography revealed severe degeneration in all BMVs. Macroscopically, BMV revealed calcification at the commissures and leaflet insertion area. Histological examination showed sporadic cells negative for endothelial nitric oxide synthase, von Willebrand factor and CD45 on their surface. In contrast, DMV showed no calcification or stenosis, and the regurgitation was trivial to moderate in all animals. Fibrotic hardening occurred only along the suture line of the valve annulus, immunostaining revealed collagen IV covering the entire leaflet surface and a repopulation with endothelial cells. Surgical implantation of DMV is feasible and results in good early graft function. Additional in vivo investigations are required to minimize the procedure-related complications and to increase the reproducibility of surgical implantation. Degenerative profile of allogeneic DMV is superior to commercially available porcine aortic prosthesis.

Is Surgical or Catheter-based Interventions an Option After an Unsuccessful Mitral Clip?

The objective of this study was to assess the results of catheter-based and surgical reinterventions in primary mitral regurgitation after failed MitraClip therapy. We report on 21 consecutive symptomatic patients with primary mitral regurgitation (median age 78 years) who underwent either repeat MitraClip therapy (n = 7) or mitral valve surgery (n = 14) after failure of the index procedure with 1-2 MitraClip implantations. At the time of reinterventions, 193 (interquartile range [IQR]: 32-622) days after the index procedure, patients had recurrent or persistent grade 3 mitral regurgitation. Early mortality at 30 days was 4.8%. Cardiac-related survival at 2 years was 85.4% (4 cardiac and 4 noncardiac deaths). Three of 7 patients with percutaneous reintervention were converted to surgery at 34, 52, and 56 days because repeat MitraClip therapy was ineffective because of pre-existing clip detachment or leaflet tear. Final therapy was biological mitral valve replacement in 14 of 21 patients (66.7%); 4 were treated with percutaneous repeat MitraClip repair (19%), and in 3 patients, surgical repairs were performed (14.3%). At follow-up with a median of 708 days, New York Heart Association class had improved significantly to class 2 (IQR: 1.0-2.5) (P = 0.0004), and the left ventricular end-diastolic diameter had decreased from 56 (IQR: 52-59) mm to 51 (48-58) mm (P = 0.0378), respectively. Recurrence of significant mitral regurgitation was absent in all but 1 patient with unsuccessful repeat MitraClip therapy who was deemed inoperable. Our data show that both repeat MitraClip and also mitral valve surgery are feasible and safe alternatives in patients without an excessively increased perioperative risk. We conclude that whenever leaflet insertion is not compromised, repeat catheter-based repair is a reasonable redo concept; in the remaining cases, surgery should be offered to the patient.

Repeat MitraClip Therapy for Significant Recurrent Mitral Regurgitation in High Surgical Risk Patients: Impact of Loss of Leaflet Insertion.

The goal of this study was to assess procedural details and outcomes of repeat MitraClip therapy. MitraClip implantation is a safe and efficacious percutaneous approach to treat significant mitral regurgitation (MR). Of 410 inoperable or high surgical risk patients treated with the MitraClip at our institution, 17 (4.1%) patients, as well as 4 patients initially treated at external institutions, underwent repeat MitraClip procedures. Mean age of the 21 patients (14 men [67%]) was 77 years; 15 patients (71%) had functional MR. Repeat procedures performed at a median of 6.3 months (range 0.7 to 34 months) after the index intervention were successful (discharge MR grade ≤2+) in 13 patients (62%), with a pronounced difference in success rate observed between the 13 patients with adequate leaflet insertion at the time of the repeat intervention and the 8 patients in whom loss of leaflet insertion (LLI) (leaflet tear/perforation or partial clip detachment) was present (11 of 13 [85%] vs. 2 of 8 [25%], respectively). The 21 patients were followed for a median of 8.5 (interquartile range: 2.3 to 18.6) months; 13 patients (62%), 8 with adequate leaflet insertion and 5 with LLI, died during follow-up. Repeat MitraClip intervention for significant recurrent MR appears to be a viable therapeutic approach in patients in whom leaflet insertion into the MitraClip is not compromised. LLI is strongly associated with repeat procedural failure.

Geometric orientation of the aortic neoroot in patients with raphed bicuspid aortic valve disease undergoing primary cusp repair and a root reimplantation procedure

Primary cusp repair + aortic root reimplantation in bicuspid aortic valve (BAV) disease presenting with root aneurysm with aortic insufficiency (AI) is an effective surgical treatment. We assessed whether the geometric orientation of the repaired BAV into its reimplanted neoroot affects outcomes-180°/180° orientation was compared with the 150°/210° orientation. From 2005 to 2012, 66 BAV repairs were performed. This is a retrospective review of all types of Ib/II BAV AI patients undergoing root reimplantation (n = 26) at two different geometric orientations: 180°/180° (n = 11) vs 150°/210° (n = 15). In the 180°/180° group, reimplantation into the neoroot was such that both conjoint and non-conjoint cusps occupied 180° of the annular circumference. In the 150°/210° group, the repaired valve was configured to the more typical native orientation of a type I BAV: the non-conjoint cusp occupied 150°, and the conjoint cusp occupied 210° of the annular circumference. Preoperative characteristics were similar in both groups. In-hospital mortality, stroke, reoperation, renal failure and pacemaker rates were zero in both groups. No patient left the operating room with >1+ AI and one had a peak gradient >20 mmHg. Transvalvular gradients were higher in the 180°/180° group, but not significant (P > 0.05). M.ean follow-ups for the 180°/180° and 150°/210° group were 48 and 33 months, respectively. Actuarial freedom from AI >2+ at 5 years was 100% in both groups. Freedom from AI >1+ at 5 years was 90 ± 10% in the 150°/210° group and 86 ± 13% in the 180°/180° group (P = 0.71). Freedom from peak gradient >20 mmHg was 80% (n = 8) in the 180°/180° group and 100% in the 150°/210° group at 1-year follow-up. Transvalvular gradients were higher in the 180°/180° group (16 ± 8 vs 10 ± 4 mmHg, P = 0.02; 9 ± 3 vs 5 ± 3 mmHg, P = 0.01). Five-year actuarial survival and freedom from aortic reoperation have remained at 100% in the entire cohort. Cusp repair + root reimplantation for BAV type Ib/II AI can be safely performed at either geometric orientation. Conceptually, 150°/210° orientation respects the natural type I BAV anatomy with regard to cusp surface area and leaflet insertion perimeter. The 180°/180° group may have higher transvalvular gradients and smaller coaptation zones than the 150°/210° group. Further follow-up may reveal the superiority of one geometric orientation over the other.

Ecophysiological traits of the macaw palm: A contribution towards the domestication of a novel oil crop

Acrocomia aculeata, or macaw palm, is a highly productive oleaginous palm tree with the potential to be a new oil crop. Plant productivity is influenced by the exchange of gases between the leaf and the atmosphere. The assimilation of CO2 is dependent on both environmental factors and the intrinsic characteristics of the leaf, such as age, position in the canopy, and nutrient and pigment content. This study was conducted to characterize some ecophysiological aspects of macaw palm cultivated under field conditions. Foliar content and gas exchange parameters were analyzed in relation to diel variation, light intensity, and the position within the canopy and rachis. The evolution of photosynthesis and related variables during the daytime followed the standard patterns for most species with C3 metabolism, reaching peak levels during the morning hours. The light curve response also displayed a C3 pattern; however, this species demonstrated a high photosynthetic capacity with a maximum net photosynthesis and apparent quantum efficiency of approximately 23μmolm−2s−1 and 0.07mol/mol, respectively. Gas exchange parameters of the fronds along the canopy varied according to the leaf position and the leaflet's insertion location within the rachis. Overall values indicate that the second and third leaves and the leaflets in the middle of the rachis have the best physiological capacity. Foliar pigment and mineral content were relatively stable among the leaves, which is a pre-requirement for long lasting leaves.

Plant regeneration of Lotononis bainesii Baker (Fabaceae) through cotyledon and leaf culture

Lotononis bainesii Baker is a promising perennial forage legume for subtropical regions. The development of tissue culture methods for in vitro plant regeneration is useful, for example, for the propagation of selected plants and germplasm conservation. In addition, it could also facilitate crop improvement methods. For this last purpose, we performed experiments to develop a tissue culture protocol for different genotypes within a cultivar and from different explants of L. bainesii . Plant regeneration was obtained for over 50% of L. bainesii cv. INIA Glencoe genotypes evaluated via cotyledon culture and 90% of genotypes evaluated by leaflet culture in a medium composed of Murashige and Skoog medium (MS) + 4.5 μM thidiazuron (TDZ). Bud elongation and rooting were obtained upon transfer onto MS + 0.044 µM 6-benzyladenine (BA) + 0.049 µM indolebutyric acid (IBA). Although immature leaflet culture resulted in a higher number of responsive genotypes than cotyledon culture, plants regenerated from cotyledons exhibited a higher survival rate when transferred to ex vitro conditions. Culture medium supplementation with either Picloram (PIC) or 2,4-dichlorophenoxyacetic acid (2,4-D) resulted in friable callus, that did not grow when subcultured. Immature leaflet insertion areas (petiole tip area where the three leaflets are attached) from expanding leaves and pieces of immature leaflets were the most efficient explants for shoot bud induction. A recommended protocol for L. bainesii plant regeneration would be placing immature leaflet explants on MS + 4.5 μM TDZ for 30 days; followed by transfer onto MS + 0.044 µM BA + 0.049 µM IBA for bud elongation and rooting. Key words: Explant type, forage legume, organogenesis, plant regeneration, shoot bud, thidiazuron.