Normal Leaflets Research Articles

Revisiting the Link Between Keratoconus and Mitral Valve Prolapse

Keratoconus is a progressive eye disease that results in thinning of the cornea, leading to visual impairment. Mitral valve prolapse (MVP) is a common disorder affecting around 2–4% of the general population. Previous studies have found an overrepresentation of MVP in individuals with keratoconus, with a prevalence of 38–65%, suggesting a shared underlying mechanism. In this case-control study, patients with keratoconus were enrolled from a quality and research registry. They were examined by a 2D echocardiography to identify if they had MVP, billowing or normal mitral leaflets. Controls were matched from the population-based Trøndelag Health Study. Patients and controls underwent a detailed echocardiographic examination to detect abnormal mitral valves. We included 101 patients (age 33 [IQR 29–40], 75% male) with keratoconus and 101 matched individuals. MVP was found in 2 (2%), while billowing was found in 5 (5%) of keratoconus patients. No significant association was found between keratoconus and the prevalence of MVP or billowing compared to the control group. Moreover, no associations were found between severity of keratoconus with presence of MVP nor with billowing of the mitral valves. We could not confirm the previously reported association between keratoconus and MVP, suggesting that routine screening for MVP in keratoconus patients may not be warranted. However, we cannot rule out the possibility of an association in other gender, age and ethnic groups different than ours.

Characteristics and results of edge-to-edge transcatheter repair of the mitral valve depending on the mechanism causing mitral regurgitation

Abstract Background Transcatheter edge-to-edge repair (TEER) has been increasingly used for selected patients with mitral regurgitation (MR), but limited data are available regarding clinical outcomes in patients with varied mechanisms of MR. Studies usually identify two types of MR: degenerative mitral regurgitation (DMR) and functional mitral regurgitation (FMR). However, patients with mixed MR etiology (MMR) are usually excluded from studies. Objective We investigated baseline echocardiographic data and clinical characteristics of three groups. Additionally, we analized the long-term prognostic impact of TEER in patients with clinically significant MR depending on the mechanism causing MR. Method Patients (n=191) who had severe MR and underwent TEER between November 2011 and Janury 2024 were included in the study. 116 patients with structurally normal mitral leaflets were classified as FMR, while 42 patients with valvular abnormalities were classified as having DMR. 33 patients with both structural and functional deformation were classified as having MMR. Results Baseline echocardiographic and clinical characteristics are summarized in Table 1. Patients with FMR were younger, had fewer comorbidities and had a larger left ventricular size than patients with DMR. Patients with MMR presented intermediate characteristics between patients with FMR and DMR. The median (p25-75) follow-up of patients was 24 (9-50) months. Time-to-event curves of survival in patients with FMR, DMR, MMR was 75% vs. 80% vs. 82%, respectively, and time event-free survival for heart failure hospitalization and all-cause mortality according to severe MR for patients with FMR, DMR, and MMR were 60% vs. 74% vs. 71% (Figure 1). In the follow up, no differences were found in terms of survival and survival free of heart failure admission or all-cause death. Conclusions The baseline characteristics of patients with FMR, DMR and MMR treated with TEER are different. Despite this, the prognosis after treatment is similar in the three groups of patients. Baseline characteristics of patients Kaplan-Meier curves

Transcatheter Approaches to Atrial Functional Mitral Regurgitation: How Far Have We Come?

Functional mitral regurgitation (MR) is associated with increased cardiovascular morbidity and mortality and over the past decade, the diagnosis of atrial functional mitral regurgitation (aFMR) has been increasingly observed in the elderly, especially in those with atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF). Annular enlargement, perturbations of annular contraction, and atriogenic leaflet tethering distinguish the pathophysiology of aFMR from the one of ventricular origin. However, no consensus provides recommendations regarding the differential diagnosis and the subsequent management of aFMR. The advent of transcatheter mitral valve repair has paved the way for various treatments including edge-to-edge repair (TEER), mitral annuloplasty, and replacement, with optimistic results on short-medium-term outcome provided by preliminary studies. In parallel, rhythm control of AF for paroxysmal and persistent types, should be pursued to induce reverse remodeling and restoring the normal leaflet coaptation. In this setting, catheter ablation aiming for electrical isolation of the pulmonary veins is the most widely recognized and effective strategy for maintaining sinus rhythm. Nevertheless, arrhythmia-free survival is lower in patients with persistent and long-term persistent AF, leading to the adoption of hybrid strategies combining transcatheter endocardial ablation and thoracoscopic epicardial surgical ablation. This review provides an update on the diagnosis and treatment of aFMR, focusing on available transcatheter approaches that can be performed in the catheterization lab and electrophysiology lab.

Aortic valve replacement in younger patients with aortic valve insuffienciency

Aortic valve replacement is the common treatment of choice for severe aortic valve insufficiency (AI). AI is often caused by aortic root dilatation which leads to valve incompetence despite structurally normal valve leaflets. For this condition, aortic repair surgery with ring annuloplasty is considered a potentially superior option. Despite the availability of different annuloplasty rings, no guidelines for the surgical procedure nor the choice of annuloplasty ring exist. In this review, we outline the surgical treatment using valve-preserving procedures as an alternative to conventional aortic valve replacement.

Distinct leaflet-annular remodeling pattern in severe atrial functional mitral regurgitation: a three-dimensional echocardiography study

BackgroundAtrial functional mitral regurgitation (AFMR) is best described with normal left ventricular size and function, structurally normal mitral leaflets and dilated left atrium. Unlike the ventricular functional phenotype, changes in the annular geometry more than the tethering forces are the main culprit for mitral regurgitation. The aim of this study is to illuminate the leaflet-annular remodeling in patients with mitral regurgitation and atrial fibrillation (AF) using three-dimensional transesophageal echocardiography (3D TOE).ResultsConsecutive fifty patients with AFMR underwent transthoracic echocardiography and 3D TOE: 25 patients with AF and non-mild MR and 25 patients with AF and mild MR were studied. A special mitral valve analysis software was used to accurately assess the three unique pillars for MR: annular size, leaflets’ geometry and tenting parameters.Compared to the mild MR group, non-mild MR group had long-standing AF of more than 1 year and larger left atrial volumes (51.83 ± 12.07 ml/m2 vs 33.68 ± 10.97 ml/m2, p < 0.001). No significant differences were noted in respect of tenting height, area and volume (13.06 ± 2.57 mm vs 11.43 ± 2.89 mm, p = 0.064, 3.58 ± 1.26 cm2 vs 2.80 ± 0.95 cm2, 0.081 and 6.70 ± 2.96 cm3 vs 5.04 ± 2.32 cm3, p = 0.081). Conversely, the non-mild MR group had larger annular area and perimeter (16.20 ± 3.90 cm2 vs 13.51 ± 3.85 cm2, p = 0.023 and 14.73 ± 1.72 cm vs 13.46 ± 1.79 cm, p = 0.033). Similarly, the non-mild MR group had larger anterior and posterior leaflets’ areas (10.18 ± 4.02 cm2 vs 8.71 ± 3.08 cm2, p = 0.04 and 8.96 ± 2.60 cm2 vs 7.30 ± 2.17 cm2, p = 0.029). Correspondingly, more disproportionate leaflet-annular remodeling, as assessed by the ratio of total leaflets’ area to the annular area, was noted in the non-mild MR as opposed to the mild MR group (1.22 ± 0.04 vs 1.26 ± 0.04, p = 0.008).ConclusionsRecently, AFMR has been recognized as a remarkable entity of secondary MR with unique mechanisms. Annular dilatation with disproportionate leaflet remodeling can validate the central regurgitation. However, the call for more parameters is being emphasized to characterize the suitable candidates for percutaneous interventions.Graphical abstract

Mitral bioprosthesis early dysfunction treated with transapical valvuloplasty during V-A ECMO.

We report the case of a 61-year-old male who had complications with a mitral valve (MV) bioprosthesis replacement by post-cardiotomy shock leading to VA ECMO implantation. The patient suffered early bioprosthetic valve failure owing to early thrombosis. The complication was successfully treated with a MV bioprosthesis transapical balloon valvuloplasty that restored normal leaflet mobility.

Evaluation of aortic wall strength in human immunodeficiency virus associated thoracic ascending aortic aneurysm: a pilot study.

Human immunodeficiency virus (HIV) associated aortopathy is associated with considerable morbidity and mortality. The pathophysiology of aortic wall strength in HIV thoracic aortic aneurysm has not been studied. The patients with HIV associated thoracic ascending aortic aneurysm (TAAA) were enrolled in the study and underwent surgery as part of their routine management. We compared collagen quantity in aneurysmal and non-aneurysmal aortic tissue in TAAA with regards to hydroxyproline concentration as a surrogate measure for collagen content and sent aneurysmal aorta for routine clinical histological assessment. This data was analysed to identify potential relations between aortic aneurysm formation and the collagen content of the aortic wall. The study included 12 patients with HIV aortopathy (9 females, median age 49 years). In total 33 tissue samples were investigated (14 aneurysmal, 13 non-aneurysmal aortic tissue and 6 aortic leaflets). There was no difference in hydroxyproline concentration of aneurysmal aortic tissue and seemingly normal tissue [19.40 (15.19-22.98) vs. 20.85 (15.55-25.83) µg/mg; P=0.82]. No difference was noted in hydroxyproline concentration among aneurysmal, seemingly normal aortic tissue and aortic valve leaflets [19.40 (15.19-22.98) vs. 20.85 (15.55-25.83) vs. 19.09 (13.94-22.00) µg/mg; P=0.86]. Histology showed fragmentation of elastin fibres in 50% of the cases. No difference in collagen concentration in the aneurysmal and non-aneurysmal aortic tissue was noted. However, most of the aneurysmal tissue had fragmentation of elastin fibres.

Abstract 14594: Dual Contrast-Enhanced Micro-Computed Tomography for Simultaneous Characterization of Macrocalcification and Tri-Layered Structural Remodeling in Explanted Human Aortic Valves

Background: Micro-computed tomography (microCT) is excellent for detecting macrocalcification but ineffective at revealing other pathologically relevant structural details in the valves affected by aortic stenosis (AS). Here, we aimed to develop a dual contrast-enhanced microCT technique to simultaneously assess macrocalcification and layer-specific remodeling in diseased human aortic valves. Methods: Diseased (n=15) and normal (n=9) aortic valve leaflets were obtained from human subjects undergoing aortic valve replacement for AS and heart transplantation/autopsy, respectively. Leaflets were fixed (4% paraformaldehyde and 2% glutaraldehyde), stained with dual contrast (1% osmium tetroxide and 1% uranyl acetate), and embedded in epoxy resin. Additional unstained leaflets (n=3 diseased, n=3 normal), similarly processed otherwise, served as staining controls. MicroCT of embedded leaflets was performed using a ZEISS Xradia 520 Versa scanner, with low energy beam (80 kVp, 5 W, LE4 filter) and high-resolution acquisitions (15 μm x 15 μm, 5 sec exposure x 1601 projections). Reconstructed images were analyzed for leaflet/layer thicknesses at midline and macrocalcification volume using Dragonfly. Results: The tri-layered tissue structure was only visualized in stained but not unstained leaflets ( p =0.002). With staining, each layer was found to be thicker in the diseased than the normal leaflets (0.28±0.13 mm vs 0.18±0.07 mm, p =0.0002 for fibrosa; 0.64±0.68 mm vs 0.29±0.19 mm, p =0.012 for spongiosa; 0.32±0.16 mm vs 0.16±0.07 mm, p &lt;0.0001 for ventricularis). The macrocalcification volume in the diseased leaflets was greater than that in the normal leaflets (84.7±84.4 mm 3 vs 0 mm 3 , p &lt;0.0001) and correlated only with the thickness of spongiosa ( r =0.79, p &lt;0.001) but not other layers ( p =0.67, p =0.26). Macrocalcification was as frequently observed in spongiosa as in fibrosa (66.7% vs 66.7% of diseased leaflets, p =0.3) but never in ventricularis. Conclusions: Dual contrast-enhanced microCT enables high-quality imaging of both macrocalcification and layer-specific remodeling in diseased human aortic valves. The results here suggest an intimate relationship between macrocalcification and spongiosa that warrants further investigation.

Abstract 14286: Rapid Involution of a Bioprosthetic Transcatheter Aortic Valve Replacement Presenting as Late Bioprosthetic Stenosis

A 65 year old male with a bioprosthetic 29 mm Edwards Sapien Ultra S3 TAVR implant for symptomatic severe aortic stenosis presented for evaluation after a 30-day transthoracic echocardiogram demonstrated bioprosthetic valve stenosis. Following TAVR deployment, TEE showed normal bioprosthetic valve function without evidence of significant paravalvular regurgitation. There were no procedural complications. Echocardiogram performed 1-day post-implantation demonstrated expected transvalvular gradients and valve area. The patient reported immediate symptomatic improvement following TAVR. At 30 days post-implant, TTE demonstrated a peak velocity of 3.37 m/s, mean gradient of 29 mmHg, dimensionless index of 0.29, and effective valve orifice area of 0.9 cm2. This was associated with a progressive decline in exercise capacity. At 57 days post-implant, TEE showed tissue growth of the aortic root anterior to the valve stent, causing deformation and under-expansion of the valve architecture from a circular to an ovoid shape. Notably, the bioprosthetic leaflets did not appear thickened or calcified, but exhibited restricted motion as a result of the abnormal valve architecture. Peak velocity had further increased to 4.6 m/s, with a mean gradient of 57 mmHg, dimensionless index of 0.21, and calculated effective orifice area of 0.52 cm2. Bioprosthetic aortic valve valve stenosis is an expected complication of valve replacement, though typically characterized by progressive leaflet calcification and pannus formation over several years or by valve thrombosis. Here, we present a rare case of rapidly progressive bioprosthetic TAVR stenosis identified at 30 days post-implantation after normal morphology and gradients on immediate and 1-day imaging. Stenosis was characterized by a process of tissue growth anterior to the stent with involution and underexpansion of the stent architecture and morphologically normal leaflet tissue.

Tissue formation and host remodeling of an elastomeric biodegradable scaffold in an ovine pulmonary leaflet replacement model.

In pursuit of a suitable scaffold material for cardiac valve tissue engineering applications, an acellular, electrospun, biodegradable polyester carbonate urethane urea (PECUU) scaffold was evaluated as a pulmonary valve leaflet replacement in vivo. In sheep (n = 8), a single pulmonary valve leaflet was replaced with a PECUU leaflet and followed for 1, 6, and 12 weeks. Implanted leaflet function was assessed in vivo by echocardiography. Explanted samples were studied for gross pathology, microscopic changes in the extracellular matrix, host cellular re-population, and immune responses, and for biomechanical properties. PECUU leaflets showed normal leaflet motion at implant, but decreased leaflet motion and dimensions at 6 weeks. The leaflets accumulated α-SMA and CD45 positive cells, with surfaces covered with endothelial cells (CD31+). New collagen formation occurred (Picrosirius Red). Accumulated tissue thickness correlated with the decrease in leaflet motion. The PECUU scaffolds had histologic evidence of scaffold degradation and an accumulation of pro-inflammatory/M1 and anti-inflammatory/M2 macrophages over time in vivo. The extent of inflammatory cell accumulation correlated with tissue formation and polymer degradation but was also associated with leaflet thickening and decreased leaflet motion. Future studies should explore pre-implant seeding of polymer scaffolds, more advanced polymer fabrication methods able to more closely approximate native tissue structure and function, and other techniques to control and balance the degradation of biomaterials and new tissue formation by modulation of the host immune response.

Functional and pathomorphological anatomy of the aortic valve and root for aortic valve sparing surgery in tricuspid and bicuspid aortic valves.

The aortic valve (AV) is a three-dimensional structure, with leaflets that are suspended within the functional aortic annulus (FAA). These structures (AV and FAA) are therefore intrinsically connected and disease of just one component can independently lead to AV dysfunction. Hence, AV dysfunction can occur in the setting of entirely normal valve leaflets. However, as these structures are functionally inter-connected, disease of one component can lead to abnormalities of the other over time. Thus, AV dysfunction is often multifactorial. Valve-sparing root procedures require an in-depth understanding of these inter-relationships, and herein we are providing a detailed account of some of the most pertinent anatomical relationships.

PO-05-097 FIRST REPORT OF CRYOABLATION OF NON-PAPILLARY MUSCLE PVCS UNDER DIRECT VISUALIZATION DURING MV REPAIR: INTER-LEAFLET TRIANGLE AND THE AORTO-MITRAL CONTINUITY

Up to 60% of patients with mitral valve prolapse (MVP) have premature ventricular contractions (PVC), usually of papillary muscle (PM) origin. However, one-third of PVCs are of non-PM origin, from areas exposed to annular stress forces. We have previously demonstrated the feasibility of intraoperative cryoablation of PM PVCs under direct visualization during mitral valve (MV) repair. To our knowledge, this is the first report of a similar approach for non-PM PVCs. We present two cases of visually-guided surgical cryoablation of non-PM PVCs at the time of elective MV repair. Both were guided by ECG morphology criteria and hybrid PET/MRI imaging pre-operatively. n/a Case 1 (Figure): 73 year old female with degenerative MVP, severe MR and frequent PVCs (27%). There were two PVC morphologies: the dominant PVC was suggestive of interleaflet triangle (ILT) origin (abrupt V3 transition), and the less frequent PVC was consistent with postero-medial PM origin. Hybrid PET-MRI demonstrated focal uptake of FDG in the LV summit region just under the aortic valve. The patient underwent an uncomplicated MV repair, TV repair and cryoablation of the ILT (open endocardial retrograde approach) and then the posterior PM. Follow up TTE showed normal MV and aortic leaflets function without regurgitation or stenosis. An event monitor at 2 months post-op revealed a PVC burden of 2% (off drugs). Case 2: 76 year old male with degenerative MVP, severe mitral regurgitation (MR) and frequent symptomatic PVCs (24%), suggestive of an aortomitral continuity (AMC) origin. Simultaneous cardiac 18F FDG-PET and MRI with LGE imaging demonstrated focal uptake of FDG in the AMC region, no LGE was detected. The patient underwent an uncomplicated MV repair, TV repair and cryoablation of the AMC. The cryo-application was performed on the atrial side of the mitral annulus with forward pressure to reach the ventricular myocardium. There were no PVCs during post-op monitoring and a 6-month follow-up monitor revealed a PVC burden of 1% (off drugs). Surgical cryoablation of non-PM PVCs under direct visualization at the time of MV surgery, using standard ECG criteria and pre-op Hybrid PET-MRI imaging, is feasible. Further studies are needed to determine the safety and effectiveness of adjunctive PVC cryoablation at the time of MV surgery.

Prevalence and Clinical Implications of Tricuspid Valve Prolapse Based on Magnetic Resonance Diagnostic Criteria

BackgroundTricuspid valve prolapse (TVP) is an uncertain diagnosis with unknown clinical significance because of a scarcity of published data. ObjectivesIn this study, cardiac magnetic resonance was used to: 1) propose diagnostic criteria for TVP; 2) evaluate the prevalence of TVP in patients with primary mitral regurgitation (MR); and 3) identify the clinical implications of TVP with regard to tricuspid regurgitation (TR). MethodsForty-one healthy volunteers were analyzed to identify normal tricuspid leaflet displacement and propose criteria for TVP. A total of 465 consecutive patients with primary MR (263 with mitral valve prolapse [MVP] and 202 with nondegenerative mitral valve disease [non-MVP]) were phenotyped for the presence and clinical significance of TVP. ResultsThe proposed TVP criteria included right atrial displacement of ≥2 mm for the anterior and posterior tricuspid leaflets and ≥3 mm for the septal leaflet. Thirty-one (24%) subjects with single-leaflet MVP and 63 (47%) with bileaflet MVP met the proposed criteria for TVP. TVP was not evident in the non-MVP cohort. Patients with TVP were more likely to have severe MR (38.3% vs 18.9%; P < 0.001) and advanced TR (23.4% of patients with TVP demonstrated moderate or severe TR vs 6.2% of patients without TVP; P < 0.001), independent of right ventricular systolic function. ConclusionsTR in subjects with MVP should not be routinely considered functional, as TVP is a prevalent finding associated with MVP and more often associated with advanced TR compared with patients with primary MR without TVP. A comprehensive assessment of tricuspid anatomy should be an important component of the preoperative evaluation for mitral valve surgery.

Caseous Mitral Annular Calcification Presenting as Retinal Artery Occlusion

Caseous mitral annular calcification (CMAC), sometimes called liquefaction necrosis of mitral annular calcification (MAC), is a rare variant of MAC, a chronic degenerative process that progresses with age. It is a degenerative abnormality of the fibrous tissue and typically involves the posterior annulus, appearing as a smooth mass with no flow or acoustic shadow artefacts. It can be differentiated from other cardiac masses by CT and MRI. Whilst benign in nature, it is associated with a range of pathologies, such as mitral valve dysfunction, arrhythmias, and systemic embolisation. Given the risk of systemic embolisation, surgery may be appropriate, but there is no clear consensus in the literature in patients who are asymptomatic. This case highlights a case of CMAC presenting with a retinal artery occlusion, and was managed conservatively. Background The mitral annulus is a key component of the mitral valve, ensuring appropriate function by facilitating complete closure of the leaflets during systole. With age, MAC can occur, potentially resulting in mitral valve dysfunction, infective endocarditis, and arrhythmias. CMAC is a rare variant of MAC, typically involving the posterior annulus. Whilst benign, the risk of complications, such as systemic embolisation, may indicate a surgical approach to management, even in patients who are asymptomatic. Case Presentation A 60-year-old female, presenting with sudden loss of vision in the lower part of her left eye due to a branch retinal artery embolus, was admitted from ophthalmology services. An outpatient transthoracic echocardiogram showed an abnormal mass on the posterior annulus of the mitral valve. Transoesophageal echocardiography identified a calcified posterior aspect of the mitral annulus with normal leaflet mobility and trivial regurgitation, and an echogenic mass attached to the ventricular aspect of the mitral annulus (at the level of posteromedial commissure), 9x4 mm in size. A cardiac CT showed a caseous mitral valve with evidence of rupture of the calcified shell. Discussion with the surgical multidisciplinary team resulted in a conservative approach, with follow-up echo for monitoring. Conclusion Whilst a benign and rare variant of MAC, CMAC is associated with a range of pathologies, including mitral valve disease, arrhythmias, and systemic embolisation. Currently, there is no standardised management approach for CMAC. Surgery is currently recommended in the context of already known surgically indicated pathologies, such as severe mitral valve disease or systemic embolisation. However, this conservatively-managed patient has had no further complications with stable echocardiographic appearance on repeat echo 3 months following initial exam.

Frequency of Ischemic Mitral Regurgitation in ST Elevation Myocardial Infarction and Its Impact on Hospital Course

Background and Aim: Ischemic mitral regurgitation (IMR) is the most prevalent complication following myocardial infarction (MI) and coronary artery disease. Acute or chronic MI can lead to IMR resulting from an abnormality in regional wall motion or dysfunction of papillary muscles in a territory with structurally normal mitral valve leaflets, coronary artery disease and chordae tendineae. The present study aimed to determine the incidence of ischemic mitral regurgitation in ST elevation myocardial infarction and its impact on hospital course. Material and Methods: This cross-sectional study was conducted on 164 myocardial infarction patients in the Department of Cardiology of Pakistan Institute Medical Sciences Hospital, Islamabad over a time period of 6 months. Institute research and ethical committee approved the study protocol. Patients with prior mitral surgery, heart failure, previous myocardial infarction, and mitral valve disorders were excluded. Demographic detail, echocardiographic parameters, and myocardial complications were recorded. Other parameters such as Killip class, in-hospital mortality, and MI territory with respect to electrocardiographic changes were recorded. Data analysis was carried out in SPSS version 26. Results: Of the total 164 MI patients, there were 114 (69.5%) male and 50 (30.5%) females. The overall mean age was 58.62±8.62 years. The incidence of IMR was 106 (64.6%), out of which the prevalence of mild, moderate, and severe MR were 86 (81.1%), 12 (11.3%), and 8 (7.6%) respectively. No significant association was found between the presence of IMR and other parameters such as diabetes, smoking, hypertension, gender, and BMI. There was a significant association between triglyceride and serum LDL-cholesterol levels with IMR presence. On comparing the IMR and no MR cases, left ventricular ejection fraction reduced but pulmonary arterial pressure increased in IMR groups. Conclusion: The present study found that the prevalence of IMR was 64.6% among MI patients and approximately half of the patients who suffer from IMR after having an AMI experience complications as a result of it. A proper treatment decision depends on assessing the severity of the MR in relation to AMI complications. Keywords: Ischemic mitral regurgitation, Myocardial infarction, ST elevation

Comparative modeling of the mitral valve in normal and prolapse conditions.

Computational modeling is one of the best non-invasive approaches to predicting the functional behavior of the mitral valve (MV) in health and disease. Mitral valve prolapse (MVP) due to partial or complete chordae tendineae rapture is the most common valvular disease and results in mitral regurgitation (MR). In this study, Image-based fluid-structure interaction (FSI) models of the human MV are developed in the normal physiological and posterior leaflet prolapse conditions. Detailed geometry of the healthy human MV is derived from Computed Tomography imaging data. To provide prolapse condition, some chords attached to the posterior leaflet are removed from the healthy valve. Both normal and prolapsed valves are embedded separately in a straight tubular blood volume and simulated under physiological systolic pressure loads. The Arbitrary Lagrangian-Eulerian finite element method is used to accommodate the deforming intersection boundaries of the blood and MV. The stress values in the mitral components, and also flow patterns including the regurgitant flow rates are obtained and compared in both conditions through the simulation. These simulations have the potential to improve the treatment of patients with MVP, and also help surgeons to have more realistic insight into the dynamics of the MV in health and prolapse. In the prolapse model, computational results show incomplete leaflet coaptation, higher MR severity, and also a significant increment of posterior leaflet stress compared to the normal valve. Moreover, it is found more deviation of the regurgitant jet towards the left atrium wall due to the posterior leaflet prolapse.

1109 PULMONARY PRESSUR TREND ANALYSIS IN PATIENTS UNDERGOING MITRACLIP

Abstract Mitral regurgitation (MR) is the second most frequent valve heart disease in Europe and its underlying mechanism primary-organic (due to disease of the mitral leaflets), or secondary-functional (where valve leaflets and chordae are structurally normal and MR results from alterations in left ventricle and left atrium geometry), determines the therapeutic approach. Transcatheter Edge-to-Edge Repair (TEER) with MitraClip implantation is a minimal-invasive treatment that according to 2021 ESC Guidelines should be considered (class of recomandation IIa) in selected symptomatic patients with severe MR despite optimal medical therapy, not eligible for surgery and fulfilling COAPT trial inclusion criteria, suggesting an increased chance of responding to treatment. Optimal valve morphology features for TEER are central pathology (second scallop), no leaflet calcifications, mitral valve area &amp;gt;4cm2, mobile length of posterior leaftel &amp;gt;10 mm, coaptation depth &amp;lt;11mm, normal leaflet strength and mobility, flail width &amp;lt;15 mm, flail gap &amp;lt;10 mm. TEER may be considered (class IIb) only in selected cases when the COAPT criteria are not fulfilled with the aim of improving symptoms and quality of life. MR occurs during systole, that at normal heart rates represents 30-50% of the cardiac cycle. As such, marked left atrial (LA) pressure elevation is present only transiently, representing less of a drive to development of secondary pulmonary hypertension compared to chronic LA pressure elevation seen in severe mitral stenosis. Anyway, in patients with severe MR echocardiography often reveals elevated systolic pulmonary artery pressure (PAPs) and MitraClip implantation usually is associated with a slight increase of the trans-mitral gradient with possible repercussions on pulmonary pressures. To better describe the effect of MitraClip implantation on pulmonary pressures and clinical outcomes we did a retrospective study enrolling in the period 2012-2022 thirty-six patients with severe mitral regurgitation treated with TEER. Compared to the last year presentation, we add eleven patients. The target was still to evaluate the clinical outcomes (symptoms, signs of heart failure, NYHA functional class) and the pulmonary pressures assessed by an echocardiographic examination before and after the intervention. At 6-month follow-up we observed in all patients with repaired mitral regurgitation an improvement in the NYHA class (from IV to II) without re-hospitalization. In addition we notice a more pronounced trend in the reduction of the mean sistolic pulmonary arterial pressure, estimated at around 2.86 mmHg ± 14 mmHg (p 0.24, 95% C.I. -7.69 to 1.94) with an unchanged left ventricle ejection fraction. Moreover, the echocardiographic exam showed a normalization of the S and D waves pattern in the pulmonary veins at the PW Doppler evaluation. These new data reinforced the idea that the clinical improvement and the reduction of dyspnea in these patients underwent TEER is related to a reduction of pressures in the pulmonary circulation regardless of the ejection fraction. This finding could be used as a tool that the cardiologist has to evaluate in the echocardiography lab to reveal a new mitral valve disfunction. Despite the addition of the new patients, the sample is still relatively small. However, considering the improvement of the results with the enlargement of the sample, the goal is to enroll additional patients to make the study even more meaningful.

Abstract 15274: Pediatric Valved Conduit From Biological Engineering in the Growing Lamb Model

Introduction: A valved conduit with growth potential for pediatric patients remains an unmet need. Here we present a novel valved conduit with growth potential based on initial data in a growing lamb model. The valve is constructed from three biologically-engineered tubes of acellular collagenous matrix possessing somatic growth potential (Syedain et al., Nat Comms, 2016) using resorbable suture with each tube contributing to create a “leaflet” (Syedain et al, Sci Transl Med, 2021). This tri-tube valve previously demonstrated growth over 52 weeks when implanted interpositionally in the pulmonary artery. Methods: In this study, a fourth tube of the same matrix is placed around the tri-tube valve to create a tubular valved conduit. The inlet segment is cut diagonally to allow for direct attachment to the myocardium, emulating a clinical repair (see figure). Results: The first two lambs to date implanted in this study exhibited normal leaflet function, a pressure gradient less than 5mmHg without regurgitation or dilatation of the conduit at 12-week echocardiography (see figure). During this time the animal’s weight increased from 34±2kg to 48±1kg. The inflow pattern with this myocardial implantation was more uniform than in the previous study that used a pulmonary artery interposition implant of the just the valve (with no conduit). Discussion: Demonstrating integration of the conduit’s matrix to the myocardium is a key step toward a clinical trial. Previous pulmonary interposition implants of the valve, while achieving integration with the adjacent artery prior to dissolution of the Maxon suture (50% loss of tensile strength in ~3 weeks, complete by ~26 weeks), did not establish this clinically relevant point of myocardial integration. Conclusion: The preliminary finding is that the valved conduit exhibits excellent function at 12 weeks in the growing lamb and integration of the conduit’s matrix with the valve annulus-myocardium will likely occur. Funding: R01 HL107572

Effectiveness of transcatheter edge-to-edge repair for atrial secondary mitral regurgitation

Abstract Background Atrial secondary mitral regurgitation (ASMR) is a subtype of SMR that is characterized by normal left ventricular (LV) function, an enlarged left atrium and mitral annulus, and flattened leaflets. This anatomical feature is different from ventricular SMR (VSMR) and might therefore impact the procedural results of transcatheter edge-to-edge repair (TEER). The effectiveness and durability of TEER in patients with ASMR has not yet been well-studied. Purpose This study aimed to investigate the effectiveness of TEER and anatomical characteristics related to optimal MR reduction in patients with ASMR. Methods We retrospectively analyzed consecutive patients who underwent MitraClip at our institution. ASMR was defined as cases that met all of the following criteria: 1) normal mitral leaflets without organic disorder, 2) LV ejection fraction &amp;gt;50%, and 3) absence of LV enlargement and segmental abnormality. The primary outcome measure was MR reduction to ≤1+, and its predictors were explored in a logistic regression analysis. Leaflet-to-annulus index (LAI) was measured using the mid-esophageal long-axis view in the A2-P2 segment as follows: (anterior leaflet length + posterior leaflet length) / anteroposterior length of the mitral annulus. Results Among 415 patients with SMR, 118 patients met the criteria for ASMR (mean age: 80±8 years; male: 39.8%) (Figure 1). Patients with ASMR had a larger mitral annulus diameter, shorter mobile posterior leaflet length, and smaller coaptation depth compared to those with VSMR. The technical success rate was 90.7%, and the MR reduction to ≤1+ after TEER was achieved in 94 (79.7%) patients with ASMR, which was comparable with VSMR. The in-hospital mortality rate was 2.5%. In multivariable logistic analysis, a large left-atrial (LA) volume index and a low LAI were associated with a lower rate of MR reduction to ≤1+ after TEER for ASMR (odds ratio [OR]: 0.98; 95% confidence interval [CI]: 0.97–0.99, and OR per 0.1 increase: 1.98; 95% CI: 1.13–3.45, respectively). The combined assessment of the LA volume index and LAI stratified the risk of residual MR ≥2+ after TEER (Figure 2). In addition, the use of a newer generation of the MitraClip systems (NTR/XTR or G4 systems) was associated with a higher rate of MR reduction to ≤1+ compared to older generations (OR: 4.65; 95% CI: 1.67–13.00). Conclusions TEER with the MitraClip system achieved a high rate of MR reduction to ≤1+ in patients with ASMR. Furthermore, the new generations of the MitraClip system may provide a more effective reduction in ASMR. Although our findings suggest that TEER with the MitraClip system is a safe and feasible approach in patients with ASMR, the combined assessment of the LA volume index and LAI might be useful to refine the device selection for transcatheter mitral valve treatment in this subgroup of SMR patients. Funding Acknowledgement Type of funding sources: None.

MECHANISTIC CLASSIFICATION AND OUTCOMES OF ISOLATED AORTIC REGURGITATION IN A CONTEMPORARY COHORT OF PATIENTS

MECHANISTIC CLASSIFICATION AND OUTCOMES OF ISOLATED AORTIC REGURGITATION IN A CONTEMPORARY COHORT OF PATIENTS