Dataset Information

In vivo dynamic strains of the ovine anterior mitral valve leaflet.

ABSTRACT: Understanding the mechanics of the mitral valve is crucial in terms of designing and evaluating medical devices and techniques for mitral valve repair. In the current study we characterize the in vivo strains of the anterior mitral valve leaflet. On cardiopulmonary bypass, we sew miniature markers onto the leaflets of 57 sheep. During the cardiac cycle, the coordinates of these markers are recorded via biplane fluoroscopy. From the resulting four-dimensional data sets, we calculate areal, maximum principal, circumferential, and radial leaflet strains and display their profiles on the averaged leaflet geometry. Average peak areal strains are 13.8±6.3%, maximum principal strains are 13.0±4.7%, circumferential strains are 5.0±2.7%, and radial strains are 7.8±4.3%. Maximum principal strains are largest in the belly region, where they are aligned with the circumferential direction during diastole switching into the radial direction during systole. Circumferential strains are concentrated at the distal portion of the belly region close to the free edge of the leaflet, while radial strains are highest in the center of the leaflet, stretching from the posterior to the anterior commissure. In summary, leaflet strains display significant temporal, regional, and directional variations with largest values inside the belly region and toward the free edge. Characterizing strain distribution profiles might be of particular clinical significance when optimizing mitral valve repair techniques in terms of forces on suture lines and on medical devices.

SUBMITTER: Rausch MK

PROVIDER: S-EPMC3111015 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature

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In vivo dynamic strains of the ovine anterior mitral valve leaflet.

Rausch Manuel K MK Bothe Wolfgang W Kvitting John-Peder Escobar JP Göktepe Serdar S Miller D Craig DC Kuhl Ellen E

Journal of biomechanics 20110401 6

Understanding the mechanics of the mitral valve is crucial in terms of designing and evaluating medical devices and techniques for mitral valve repair. In the current study we characterize the in vivo strains of the anterior mitral valve leaflet. On cardiopulmonary bypass, we sew miniature markers onto the leaflets of 57 sheep. During the cardiac cycle, the coordinates of these markers are recorded via biplane fluoroscopy. From the resulting four-dimensional data sets, we calculate areal, maximu ...[more]

PMID: 21306716

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Project description:ObjectiveMitral valve repair is superior to replacement for degenerative disease, but long-term outcomes of anterior versus posterior leaflet repair remain poorly defined. We propensity matched anterior and posterior repairs to compare long-term outcomes.MethodsPatients undergoing first-time degenerative mitral repair between 1992 and 2018 were identified. Primary outcome was overall survival. Secondary outcomes were postprocedural residual mitral regurgitation and reoperation. From 1025 patients, 1:1 propensity score matching was performed, yielding 309 anterior (isolated anterior = 85, bileaflet = 224) and 309 isolated posterior repairs.ResultsAge was 58 ± 15 years, ejection fraction was 57% ± 10%, and matched groups were well balanced. Anterior repairs had longer bypass (122 ± 53 vs 109 ± 43 minutes, P = .001) and crossclamp (94 ± 44 vs 85 ± 62 minutes, P = .033) times. Mean residual mitral regurgitation grade was 0.44 (95% confidence interval, 0.24-0.65) for anterior repair and 0.30 (95% confidence interval, 0.13-0.47) for posterior repair (P = .31). Overall, 92% (569/618) of matched patients had no residual mitral regurgitation, with no differences in mitral regurgitation grade between groups (P = .77). Survival did not differ between anterior (10 years: 72% ± 7%; 15 years: 63% ± 7%) and posterior (10 years: 74% ± 7%; 15 years: 60% ± 8%) groups (log-rank P = .93). Linearized incidence of reoperation was 0.62% per patient-year, including 0.74% for anterior and 0.48% for posterior repairs. Cumulative incidence of reoperation at 15 years was 7.5% after anterior repair and 4.9% after posterior repair (Gray's test P = .26).ConclusionsNo long-term survival or reoperation difference was found between posterior and anterior repair. On the basis of these findings, surgeons at centers of excellence should aim for repair of both anterior and posterior leaflet pathology with the same decision-making threshold over valve replacement for degenerative mitral disease.

Project description:ObjectivesThe aim of this study was to test the hypothesis that transcatheter electrosurgery might allow intentional detachment of previously placed MitraClip(s) from the anterior leaflet to recreate a single mitral orifice for transcatheter mitral valve implantation (TMVI), leaving the retained MitraClip(s) securely fastened to the posterior leaflet and without interfering with the mitral bioprosthesis.BackgroundPatients with severe mitral regurgitation or stenosis despite edge-to-edge mitral repair with the MitraClip typically have few therapeutic options because the resultant double orifice precludes TMVI. Transcatheter electrosurgery may allow detachment of failed MitraClip(s) from the anterior leaflet to recreate a single orifice for TMVI.MethodsThis was a single-center, 5-patient, consecutive, retrospective observational cohort. Patients underwent transcatheter electrosurgical laceration and stabilization of failed MitraClip(s) to recreate a single orifice, leaving the MitraClip(s) securely fastened to the posterior leaflet. Subsequently, patients underwent TMVI with an investigational device, the Tendyne mitral bioprosthesis, on a compassionate basis. Patients were followed up to 30 days.ResultsMitraClip detachment from the anterior leaflet and Tendyne implantation were successful in all patients. All patients survived to discharge. All patients were discharged with grade 0 central mitral regurgitation. Two patients had moderate perivalvular mitral regurgitation that did not require reintervention. During the follow-up period of 30 days, there were no deaths, cases of valve dysfunction, or reintervention. There was no evidence of erosion or bioprosthetic valve dysfunction attributable to the retained MitraClip(s) still attached to the posterior leaflet.ConclusionsTranscatheter electrosurgical detachment of failed MitraClips from the anterior leaflet followed by TMVI is technically feasible and safe at 30 days. Longer term study is needed to determine the clinical benefit of this approach and new algorithms for TMVI sizing following electrosurgical laceration and stabilization of a failed MitraClip to avoid perivalvular leak.

Project description:BackgroundLeft ventricular outflow tract (LVOT) obstruction is a leading cause of mortality and exclusion from transcatheter mitral valve replacement (TMVR). Intentional laceration of the anterior mitral valve leaflet to prevent LVOT obstruction (LAMPOON) is a transcatheter mimic of surgical chord-sparing leaflet resection.ObjectivesThe purpose of this prospective multicenter trial was to study LAMPOON with transseptal (Edwards Lifesciences, Irvine, California) TMVR in annuloplasty rings or native mitral annular calcification (MAC).MethodsSubjects at high or extreme surgical risk and prohibitive risk of LVOT obstruction from TMVR were included. Eligibility was modified midtrial to exclude subjects with threatened LVOT obstruction from a Sapien 3 valve fabric skirt. The primary endpoint was procedure survival with successful LAMPOON, with successful TMVR, without reintervention, and with LVOT gradient <30 mm Hg ("optimal") or <50 mm Hg ("acceptable"). Secondary endpoints included 30-day mortality and major adverse cardiovascular events. There was universal source-data verification and independent monitoring. All endpoints were independently adjudicated. Central laboratories analyzed echocardiogram and CT images.ResultsBetween June 2017 and June 2018, 30 subjects were enrolled equally between the MAC and ring arms. LAMPOON traversal and midline laceration was successful in 100%. Procedure survival was 100%, and 30-day survival was 93%. Primary success was achieved in 73%, driven by additional procedures for paravalvular leak (10%) and high-skirt neo-LVOT gradients observed before a protocol amendment. There were no strokes.ConclusionsLAMPOON was feasible in native and annuloplasty ring anatomies in patients who were otherwise ineligible for treatment, with acceptable safety. LAMPOON was effective in preventing LVOT obstruction from TMVR. Despite LAMPOON, TMVR using Sapien 3 in annuloplasty rings and MAC still exhibits important limitations. (NHLBI DIR LAMPOON Study: Intentional Laceration of the Anterior Mitral Leaflet to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Implantation; NCT03015194).

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In vivo dynamic strains of the ovine anterior mitral valve leaflet.

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In vivo dynamic strains of the ovine anterior mitral valve leaflet.

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