Impact of Mitral Annular Dilation on Edge-to-Edge Therapy With MitraClip-XTR

Background: Mitral annular dilation has been shown to challenge successful edge-to-edge therapy with earlier MitraClip generations. Recently, third-generation MitraClip-XTR with extended clip arm length was introduced. We assessed the impact of annular dilation on residual mitral regurgitation (MR) after MitraClip-XTR repair and sought to identify cutoffs associated with suboptimal MR reduction. Methods: We included 107 patients (78.9±6.7 years; 40.2% female) with symptomatic severe MR (46.7% primary MR; 53.3% secondary MR) undergoing MitraClip-XTR repair. Annular dimensions were retrospectively assessed by 2-dimensional and 3-dimensional-transesophageal echocardiography including a semiautomated analysis. Impact of annular diameters and area on suboptimal reduction defined as ≥2+MR on transthoracic echocardiography at discharge was assessed and predictive cutoff values identified. Previously identified predictors of suboptimal outcome after MitraClip therapy were included in multivariable analysis. Results: Technical success was achieved in 93%, 1-year mortality was 23%. Suboptimal MR reduction was observed in 26% and associated with higher 1-year mortality (odds ratio, 4.5 [1.5–14.1]). End-systolic anteroposterior and intercommissural annular diameters, annular area and further vena-contracta width, effective regurgitant orifice area and left atrial volume were associated with suboptimal outcomes. Independent predictors of suboptimal reduction were end-systolic annular area (odds ratio, 1.36 [1.08–1.71] per cm 2 ) and vena-contracta width (odds ratio, 1.47 [1.04–2.09] per mm). On receiver operating characteristic analysis, 3-dimensional-transesophageal echocardiography end-systolic anteroposterior diameter >40.5 mm, intercommisural diameter >40.5 mm, and annular-area >12.50 cm 2 were the most predictive thresholds for suboptimal reduction. If all 3 annular measurements exceeded the determined threshold values, the risk for suboptimal reduction increased by 17-fold. Conclusions: Annular dilation was found to challenge successful edge-to-edge therapy also with extended-reach MitraClip-XTR. Our proposed thresholds for preprocedural annular dimensions may serve as guidance for improved patient selection in edge-to-edge repair.

Influence of Annular Dynamics and Material Behavior in Finite Element Analysis of Barlow’s Mitral Valve Disease

Barlow’s disease affects the entire mitral valve apparatus, by altering several of the fundamental mechanisms in the mitral valve which ensures unidirectional blood flow between the left atrium and the left ventricle. In this paper, a finite element model of a patient diagnosed with Barlow’s disease with patient-specific geometry and boundary conditions is presented. The geometry and boundary conditions are extracted from the echocardiographic assessment of the patient prior to surgery. Material properties representing myxomatous, healthy human and animal mitral valves are implemented and computed response are compared with each other and the echocardiographic images of the patient. This study shows that the annular dilation observed in Barlow’s patients controls several aspects of the mitral valve behavior during ventricular systole. The coaptation of the leaflets is observed to be highly dependent on annular dilation, and the coaptation area reduces rapidly at the onset of mitral regurgitation. Furthermore, the leaflet material implementation is important to predict lack of closure in the FE model correctly. It was observed that using healthy human material parameters in the Barlow’s diseased FE geometry gave severe lack of closure from the onset of mitral regurgitation, while myxomatous material properties showed a more physiological leakage.

Abstract 14327: Tricuspid Valve Annular Area Correlations and Determinants in Healthy Controls and Patients With Severe Mitral Regurgitation

Introduction: Concomitant tricuspid valve (TV) repair during mitral valve (MV) surgery based on annular dilation rather than the degree of regurgitation (TR) has been shown to be beneficial and is supported by the guidelines. Hypothesis: Assess the correlations between tricuspid and mitral annular areas (TVA and MVA, respectively) indexed to body surface area (BSA) measured by cardiac computed tomography (CT), and identify the determinants of the TVA in normal and diseased states. Methods: We included 50 consecutive controls (no valvular heart disease undergoing coronary CTA), 50 primary mitral regurgitation (PMR) patients referred for robotic repair, and 25 functional MR (FMR) patients referred for percutaneous therapy, without significant associated TR (≤2+ TR). We used dedicated CT software (Aquarius, TeraRecon) to perform the annular measurements. A mid-diastolic phase acquisition (~70%) was used Results: Patients with FMR were older (median age [25th, 75th] = 70 years [63,77.5] vs. 55 [48,59] in PMR and 48 [38,55] in controls), had more clinical comorbidities, and lower ejection fraction (32% [23,40] vs. >60% in both other groups). TVA was significantly correlated to MVA in controls (r≥0.5; p<0.001), as well as in patients with PMR and FMR. (Figure 1). Table 1 shows the univariate correlations and multivariate determinants of the TVA. In the multivariate analysis, the MVA, RA area, and LVEDV were the independent predictors of TVA. Interestingly, the MVA was the most important predictor (β= 0.420, p<0.001). Conclusion: In individuals without valvular heart disease and in patients with severe MR (PMR and FMR) with ≤ 2+ TR, the TVA was largely determined by the MVA.

Abstract 16830: Functional Stenosis After Undersizing Mitral Annuloplasty is Governed by Pre-Operative Mitral Valve Opening Geometry

Introduction: Surgical repair of functional mitral regurgitation (FMR) with undersizing mitral annuloplasty (UMA) is a common practice. Though excessive annular downsizing can improve coaptation, it raises the risk of functional mitral stenosis (FMS). Predicting if certain patients can develop FMS after UMA, can help with surgical planning and inform the safe levels of downsizing. In this study, we sought to investigate that the pre-operative diastolic geometry of the mitral valve can predict the risk of developing FMS with UMA. Methods: Pig mitral valves (n=8) were excised and mounted into a left heart simulator with steady diastolic flow only [ Fig1A ]. Three leaflet tethering patterns were mimicked in this model: annular dilation (AD), AD + asymmetric tethering (Asym) and AD + symmetric tethering (Sym) [ Fig1B ]. Under each condition, the annulus was downsized to different levels by an adjustable UMA [ Fig1C ]. Millar pressure catheter and Echocardiography were used to measure MV pressure gradient and diastolic configuration under various conditions. Results: Under each tethering geometry (AD, AD + Asym and AD + Sym respectively), pressure gradient gradually increases as the downsizing level increases. Also, at each specific level of downsizing, pressure gradient increases as the subannular tethering increases. Similarly, at each specific level of downsizing, EOA decreases as the subannular tethering increases. Under each tethering geometry, EOA also decreases as the downsizing level increases [ Fig1D ]. In addition, it is demonstrated that at different flow rates, both pressure gradient and EOA correlates with anterior diastolic angle, which is impacted mainly by preoperative subannular tethering [ Fig1E ]. Conclusions: In FMR, the hemodynamic outcome of MV after UMA depends on both the extent of annular downsizing and preoperative leaflet tethering geometry, both of which should be taken into account when deciding the optimal surgical intervention.

Abstract 17158: Patient-Specific Analysis of Pre-Surgical Leaflet Deformations to Predict Outcomes of Surgical Repair for Ischemic Mitral Regurgitation

Introduction: Ischemic mitral regurgitation (IMR) is a highly prevalent disorder, and current methods of repair have suboptimal rates of failure. Accounting for patient-specific variations in the pre-surgical deformation patterns of the mitral valve (MV) may allow for better prediction of post-surgical outcomes. Methods: Real-time 3D echocardiographic images of the MV were segmented to create geometric representations for 20 patients (10 with and 10 without IMR recurrence) immediately pre- and post-annuloplasty repair as well as for 5 healthy MVs. To build correspondence between the open and closed valve geometries in each state, we morphed the open state geometry to the closed state shape within a finite element framework. Metrics including directional in-plane strains, leaflet area, and orifice dimensions were then computed and compared between the valves with and without recurrent IMR. Results: We found that MVs with IMR had significantly lower magnitudes of compressive circumferential strain in the posterior leaflet and higher radial strains across the whole MV than MVs without IMR (Figure). Patients who would later exhibit MR recurrence were found to have significantly higher circumferential leaflet strain in the anterior commissure prior to surgery than those without recurrence (p = 0.0228). The recurrent MVs also had significantly larger leaflet areas and annuli than the non-recurrent MVs, and their annuli contracted less. Conclusions: Key characteristics of IMR including increased downward leaflet tethering, annular dilation, and reduced ability to contract were most pronounced in MVs with recurrent IMR, suggesting that valves with recurrence may be in a more progressed disease state pre-surgically or may have a different manifestation of the myocardial infarct. Such factors could be used to predict post-surgical IMR recurrence and improve surgical planning.

Determinants of clinical outcomes of surgery for isolated severe tricuspid regurgitation

ObjectivesAlthough the incidence of patients with isolated tricuspid regurgitation (TR) is increasing, data regarding the clinical outcomes of isolated TR surgery are limited. This study sought to investigate the prognostic implications according to procedural types, and to identify preoperative predictors of clinical outcomes after isolated TR surgery.MethodsAmong consecutive 2610 patients receiving tricuspid valve (TV) procedure, we analysed 238 patients (age, 59.6 years; 143 females) who underwent stand-alone TV surgery (repair, 132; replacement, 106) for severe TR. Primary outcome was the composite of all-cause mortality and heart transplantation. Clinical outcomes between the repair and the replacement groups were compared after adjusting with the inverse probability of treatment weighting (IPTW) method.ResultsDuring follow-up (median, 4.1 years), 53 patients died and 4 received heart transplantation. Multivariable analysis revealed that age (p=0.001), haemoglobin level (p=0.003), total bilirubin (p=0.040), TR jet area (p=0.005) and right atrial (RA) pressure (p=0.022) were independent predictors of the primary outcome. After IPTW adjustment, there were no significant intergroup differences in the risk of primary outcome (HR 1.01; 95% CI 0.55 to 1.87). In the subgroup analysis, tricuspid annular diameter was identified as a significant effect modifier (p=0.012) in the comparison between repair versus replacement, showing a trend favouring replacement in patients with annular diameter >44 mm.ConclusionsThe outcomes of stand-alone severe TR surgery were independently associated with the severity of TR and RA pressure. In selected patients with severe annular dilation >44 mm, replacement may become a feasible option.

The role of strut chordae in mitral valve competence during annular dilation

Strut chordae, on their own, are not typically thought to aid mitral valve competence. The aim of this study is to assess whether strut chordae aid mitral valve competence during acute annular dilation. Twelve porcine hearts were dissected and tested using an in vitro simulator, with the mitral annulus tested in either a ‘normal’ or a dilated configuration. The normal configuration included a diameter of 30 mm, a posterior leaflet ‘radius’ of 15 mm and a commissural corner ‘radius’ of 7.5 mm; the dilated annular template instead used dimensions of 50 mm, 25 mm and 12.5 mm, respectively. Each mitral valve underwent ten repeat tests with a target systolic pressure of 100 mmHg. No significant difference in the pressure was detected between the dilated and regular annuli for the mitral valves tested (95 ± 3 mmHg cf. 95 ± 2 mmHg). However, the volume of regurgitation for a dilated annulus was 28 ml greater than for a valve with a normal annulus. Following severing of strut chordae, there was a significant reduction in the systolic pressure withstood before regurgitation by mitral valves with dilated annuli (60 ± 29 mmHg cf. 95 ± 2 mmHg for normal annular dimensions; p < 0.05). In conclusion, strut chordae tendineae may play a role in aiding mitral valve competence during pathophysiology.