Project description:Proper blood flow through the atrioventricular heart valves (AHVs) relies on the holistic function of the valve and subvalvular structures, and a failure of any component can lead to life-threatening heart disease. A comprehension of the mechanical characteristics of healthy valvular components is necessary for the refinement of heart valve computational models. In previous studies, the chordae tendineae have been mechanically characterized as individual structures, usually in a clamping-based approach, which may not accurately reflect the in vivo chordal interactions with the leaflet insertion and papillary muscles. In this study, we performed uniaxial mechanical testing of strut chordae tendineae of the AHVs under a unique tine-based leaflet-chordae-papillary muscle testing to observe the chordae mechanics while preserving the subvalvular component interactions. Results of this study provided insight to the disparity of chordae tissue stress-stretch responses between the mitral valve (MV) and the tricuspid valve (TV) under their respective emulated physiological loading. Specifically, strut chordae tendineae of the MV anterior leaflet had peak stretches of 1.09-1.16, while peak stretches of 1.08-1.11 were found for the TV anterior leaflet strut chordae. Constitutive parameters were also derived for the chordae tissue specimens using an Ogden model, which is useful for AHV computational model refinement. Results of this study are beneficial to the eventual improvement of treatment methods for valvular disease.
Project description:Aims: This study aimed to investigate the pathology, classification, diagnosis, and surgical prognosis of UCMV. Methods and Results: Consecutive paediatric patients with ≥ moderate-severe mitral regurgitation (MR) and mitral stenosis (MS) were recruited between October 2016 and July 2020. UCMV was diagnosed and classified into three grades according to the involvement of chorda groups and MS presence or absence; other mitral lesions were included as controls. Of 207 eligible patients, 75 with UCMV (10.0 m [interquartile range (IQR): 6.0-21.5]) and 110 with other mitral lesions (16.0 m [IQR: 5.0-43.5]) were diagnosed using echocardiography and surgical exploration. The associated chorda groups of UCMV were confirmed to show high agreement between echocardiography and surgery (kappa = 0.857, p < 0.001). At baseline surgery assessment, the UCMV group exhibited worse New York Heart Association functional class, more severe MR and MS grades, and fewer associated complex anomalies (all, p < 0.05) than the control group. After a mean follow-up of 8.3 (IQR:2.7-14.4) months and adjustment for covariates, the UCMV group required longer cardiopulmonary bypass and aortic clamp times, but there were no differences in the incidence of adverse events (p = 0.584). Class III was associated with higher risk of adverse events than classes I and II (p = 0.002). Conclusions: The UCMV spectrum constitutes a primary pathogenesis of paediatric MV dysfunction, which can be optimally diagnosed using echocardiography. Classification based on mitral anatomy and dysfunction can predict the risk of postoperative adverse events.
Project description:Polymorphisms in Lys939Gln XPC gene may diminish DNA repair capacity, eventually increasing the risk of carcinogenesis. The aim of the present study was to evaluate the significance of polymorphism Lys939Gln in XPC gene in patients with mitral chordae tendinea rupture (MCTR). Twenty-one patients with MCTR and thirty-seven age and sex matched controls were enrolled in the study. Genotyping of XPC gene Lys939Gln polymorphism was carried out using polymerase chain reaction- (PCR-) restriction fragment length polymorphism (RFLP). The frequencies of the heterozygote genotype (Lys/Gln-AC) and homozygote genotype (Gln/Gln-CC) were significantly different in MCTR as compared to control group, respectively (52.4% versus 43.2%, p = 0.049; 38.15% versus 16.2%, p = 0.018). Homozygote variant (Gln/Gln) genotype was significantly associated with increased risk of MCTR (OR = 2.059; 95% CI: 1.097-3.863; p = 0.018). Heterozygote variant (Lys/Gln) genotype was also highly significantly associated with increased risk of MCTR (OR = 1.489; 95% CI: 1.041-2.129; p = 0.049). The variant allele C was found to be significantly associated with MCTR (OR = 1.481; 95% CI: 1.101-1.992; p = 0.011). This study has demonstrated the association of XPC gene Lys939Gln polymorphism with MCTR, which is significantly associated with increased risk of MCTR.
Project description:ObjectiveWe sought to develop an instrument that would enable the delivery of artificial chordae tendineae (ACT) using optical visualization of the leaflet inside the beating heart.MethodsA delivery instrument was developed together with an ACT anchor system. The instrument incorporates an optically clear silicone grasping surface in which are embedded a camera and LED for direct leaflet visualization during localization, grasping, and chordal delivery. ACTs, comprised of T-shaped anchors and an expanded polytetrafluoroethylene chordae, were fabricated to enable testing in a porcine model. Ex vivo experiments were used to measure the anchor tear-out force from the mitral leaflets. In vivo experiments were performed in which the mitral leaflets were accessed transapically using only optical guidance and ACTs were deployed in the posterior and anterior leaflets (P2 and A2 segments).ResultsIn 5 porcine ex vivo experiments, the mean force required to tear the anchors from the leaflets was 3.8 ± 1.2 N. In 5 porcine in vivo nonsurvival procedures, 14 ACTs were successfully placed in the leaflets (9 in P2 and 5 in A2). ACT implantation took an average of 3.22 ± 0.83 minutes from entry to exit through the apex.ConclusionsOptical visualization of the mitral leaflet during chordal placement is feasible and provides direct feedback to the operator throughout the deployment sequence. This enables visual confirmation of the targeted leaflet location, distance from the free edge, and successful deployment of the chordal anchor. Further studies are needed to refine and assess the device for clinical use.
Project description:BackgroundParachute mitral valve with reticular chordae tendineae is an extremely rare anomaly.Case presentationWe present a case of parachute mitral valve associated with distinctive reticular chordae tendineae in an adult. It was diagnosed from the echocardiogram. The patient was referred for surgery. Valve analysis showed thickened mitral valve leaflets and commissures. The chordae tendinae were lengthy and thick. All the chordae tendinae merged into a solitary papillary muscle. A distinctive reticular fibrous tissue was found on mitral valve apparatus as the chordae tendinae intermixed each other. The only functional communication between the left atrium and the left ventricle was through the reticular spaces. This anomaly was considered to be unrepairable and was replaced with a mechanical valve.ConclusionsAn extremely rare and unique case of parachute mitral valve associated with reticular chordae tendineae was reported. Mitral valve replacement is a reasonable choice in patients with parachute mitral valve with reticular chordae tendineae.
Project description:BackgroundAlthough systolic anterior motion (SAM) of the mitral valve anterior leaflet is well-known to cause hemodynamic perturbation in many anesthetic situations, the prevalence and clinical implication of SAM of mitral chordae tendineae (chordal SAM) in liver transplantation (LT) has not been evaluated. We aimed to assess the impact of chordal SAM on intraoperative postreperfusion syndrome and short and long-term all-cause mortality.MethodsWe retrospectively evaluated 1751 LT recipients from January 2011 to June 2017 who had preoperative echocardiography. Echocardiography-derived parameters and the prevalence of post-reperfusion syndrome between those with chordal SAM and without chordal SAM were compared. The cumulative mortality rate according to the presence of chordal SAM was evaluated by the Kaplan-Meier survival curve.ResultsOf the enrolled recipients, 21 (1.2%) had chordal SAM in preoperative echocardiography. Compared to those without chordal SAM, patients with chordal SAM had a smaller end-systolic volume index (median 18 ml/m2 vs. 22 ml/m2, P = 0.015) and end-diastolic volume index (median 52 ml/m2 vs. 63 ml/m2, P = 0.011). However, there was no difference in systolic and diastolic function in echocardiography. The prevalence of intraoperative post-reperfusion syndrome did not show any difference (42.9% vs. 45.3%, P = 1.000). Over the mean 4.8-year follow-up, cumulative 90-day and overall mortality also did not show a difference (Log rank P > 0.05, both).ConclusionsPreoperative screening of echocardiography in LT recipients detects 1.2% of chordal SAM. It is found with small left ventricular volume, but is not related with intraoperative post-reperfusion syndrome and short- and long-term postoperative all-cause mortality in LT.
Project description:Highlights•Accessory mitral tissue and left atrial chordae are rare congenital abnormalities.•Accessory mitral tissue can result in left ventricular outflow tract and mitral valve obstruction.•This is the first case of lateral mitral accessory tissue with an associate anomalous chord.•Transthoracic echocardiography may not be able to evaluate accessory mitral valve tissue.•Removal of anomalous chordae affecting the mitral valve may be complicated.
Project description:Accessory mitral valve tissue is commonly associated with other congenital heart diseases and is usually detected in children causing left ventricular outflow tract obstruction. We present an adult patient with isolated non-obstructive accessory mitral valve tissue that was mimicking ruptured chordae of the mitral valve. Accessory mitral valve tissue in adults is very rare and can mimick various causes of left ventricular outflow tract obstruction. This patient represents the first case in literature wherein an unobstructive accessory mitral valve tissue simulated a ruptured chordae. This case illustrates that in patients with suspected mitral valve chordae rupture without any mitral regurgitation, this diagnosis should be considered, which can have therapeutic implications.
Project description:Infective endocarditis (IE) is primarily a bacterial infection of the heart valves. The most common organisms implicated include Staphylococcus and Streptococcus species. However, with the advent of MALDI-TOF and molecular techniques, the reports of IE being caused by rare organisms are on a rise. Here we describe a case of IE due to Abiotrophia defectiva. This is the first report of simultaneous infection of both mitral and aortic valves by Abiotrophia defectiva from India. IE caused by Abiotrophia defectiva has been seen to be more severe, associated with higher failure rates and relapse. This emphasizes the accurate identification of nutritionally variant Streptococcus (NVS) species as the management of choice varies between Abiotrophia and Granulicatella.