Congenital malformations of the mitral valve

Atherosclerosis, calcific aortic valve disease and mitral annular calcification: same or different?

There are similarities in the pathophysiologic mechanisms of atherosclerosis, calcific aortic valve disease (CAVD) and mitral annular calcification (MAC), however, medical treatment to slow or stop the progression of CAVD or MAC has been more elusive as compared to atherosclerosis. Atherosclerosis and CAVD share common demographic, clinical, protein, and genetic factors even more so than with MAC, which supports the possibility of shared medical therapies, though abrogating calcific extracellular vesicle shedding could be a common target for all three conditions. Herein, we summarize the overlapping and distinct pathways for further investigation, as well as key areas where additional research is needed.

Clinical and 2D/3D-Echo Cardiography Determinants of Mitral Valve Reoperation in Children With Congenital Mitral Valve Disease

Background

Congenital mitral valve disease (CMVD) presents major challenges in its medical and surgical management.

Objectives

The purpose of this study was to investigate the value of 3-dimensional echocardiography (3DE) and identify associations with MV reoperation in this setting.

Methods

All children <18 years of age who underwent MV reconstruction for CMVD in 2002 to 2018 were included. Preoperative and postoperative 2-dimensional echocardiography (2DE) and 3DE data were collected. Competing risks and Cox regression analysis were used to identify independent associations with MV reoperation. Receiver operating characteristic and decision-tree analysis were implemented for comparison of 3DE vs 2DE.

Results

A total of 206 children underwent MV reconstruction for CMVD (mitral stenosis, n = 105, mitral regurgitation [MR], n = 75; mixed disease, n = 26); 64 (31%) required MV reoperation. Variables independently associated with MV reoperation were age <1 year (HR: 2.65; 95% CI: 1.13-6.21), tethered leaflets (HR: 2.00; 95% CI: 1.05-3.82), ≥ moderate 2DE postoperative MR (HR: 4.26; 95% CI: 2.45-7.40), changes in 3D-effective orifice area (3D-EOA) and in 3D-vena contracta regurgitant area (3D-VCRA). Changes in 3D-EOA and 3D-VCRA were more strongly associated with MV reoperation than changes in mean gradients (area under the curve [AUC]: 0.847 vs AUC: 0.676, P = 0.006) and 2D-VCRA (AUC: 0.969 vs AUC: 0.720, P = 0.012), respectively. Decision-tree analysis found that a <30% increase in 3D-EOA had 80% accuracy (HR = 8.50; 95% CI: 2.9-25.1) and a <40% decrease in 3D-VCRA had 93% accuracy (HR: 22.50; 95% CI: 2.9-175) in discriminating MV reoperation for stenotic and regurgitant MV, respectively.

Conclusions

Age <1 year, tethered leaflets, 2DE postoperative MR, changes in 3D-EOA and 3D-VCRA were all independently associated with MV reoperation. 3DE parameters showed a stronger association than 2DE. 3DE-based decision-tree algorithms may help prognostication and serve as a support tool for clinical decision-making.

Moderate mitral regurgitation in association with ventricular septal defect in children: Does it warrant mitral valve repair?

Background

The management of ventricular septal defect (VSD) alongside mitral regurgitation (MR) in pediatric patients remains a contentious issue due to the intricacies of cardiac surgery and the need to minimize ischemic time. Despite observations of MR regression following VSD closure, definitive guidelines for this patient subset are lacking, particularly concerning the management of the subgroup of patients with moderate MR. The objective of the study is to explore the factors influencing the choice between surgical intervention and conservative management for the mitral valve (MV) in VSD patients with moderate MR.

Materials and Methods

A retrospective cohort study from January 2000 to December 2015, we analyzed management trends and focused on 53 patients with both VSD and moderate MR. This cohort was subdivided into four groups: first by their MV pathology, and then stratified by the receipt of intervention towards the diseased MV. Our primary goal was to identify correlations, especially concerning surgical outcomes such as mortality and need for re-operation. Statistical significance is determined when the P value is lower than 0.05.

Results

There were no notable differences in preoperative variables across four cohort groups, apart from the cross-clamp duration which was longest in Group B intervention. Outcome analysis showed survival rates that were higher in cohort groups that underwent intervention toward the disease MV regardless of existing MV morphology, although results were not statistically significant. Cox model analysis found no correlation between the cohort groups and postoperative outcomes, but cross-clamp duration significantly correlated with mortality.

Conclusions

In cases of VSD with moderate MR with associated pathologies of the valvular apparatus, opting for MV repair (MVr) appears to improve survival outcomes without significantly increasing postoperative morbidity. Similarly, for patients with moderate MR and isolated annular dilatation, surgical MVr is observed to have better survival trend compared to the control group.

Non-syndromic Parachute Mitral Valve "When the Valve Dives in": Case Report and Review of the Literature

A parachute mitral valve (PMV) is a congenital mitral valve anomaly diagnosed in infancy, and it can also be discovered in adults during echocardiography. Surgical management is common in infants to prevent complications from left-heart obstructions. In adults, PMV may be found independently or with other cardiac defects. Prophylactic antibiotics are recommended for certain congenital heart anomalies before dental procedures. A study suggests reconsidering guidelines to include anomalies like bicuspid aortic valve and MVP for antibiotic prophylaxis. PMV, with transvalvular blood flow turbulence, may increase the risk of infective endocarditis, as seen in a reported case with a parachute-like mitral valve. Here, we present the case of a 62-year-old female incidentally found to have a PMV during an echocardiogram.

Mitral annular disjunction and Pickelhaube sign in children with mitral valve prolapse: A prospective cohort study

BACKGROUND

Mitral annular disjunction (MAD) and the Pickelhaube sign are identified as risk factors for malignant ventricular arrhythmias (VAs) and sudden cardiac death in adults with mitral valve prolapse (MVP); their prevalence and consequences in children have never been studied.

OBJECTIVES

To determine the proportion of MAD in children with MVP, and its potential link with VAs.

METHODS

A cohort of 49 consecutive children (mean age 12.8±3.0 years; 33 females) with MVP and comprehensive clinical arrhythmia (24-hour monitoring) and Doppler echocardiographic characterization, including pulsed-wave tissue Doppler (PWTD) of the lateral mitral annulus, was identified. The relationship between clinical and echocardiographic data and presence of VAs was studied.

RESULTS

MAD was common (n=25; 51%). Only five patients had significant VAs (Lown grade>2) characterized by polymorphic premature ventricular contractions or couplets. MAD was not associated with VAs on 24-hour Holter monitoring, but an association was found between VAs and spiked high-velocity midsystolic signal>16cm/s on PWTD (Pickelhaube sign) (P=0.004), myxomatous mitral valve (P=0.004) and left ventricular dilatation (P=0.01). T-wave inversion in inferolateral leads on electrocardiogram was more frequent in patients with versus without the Pickelhaube sign (P=0.03). No difference was found between patients with or without MAD regarding sex, history of palpitation, severity of mitral regurgitation, aortic root diameter and incidence of connective tissue disorders. Myocardial fibrosis was detected in two of three patients who underwent a complementary cardiac magnetic resonance examination.

CONCLUSIONS

MAD is common in children with MVP; its presence was not associated with significant VAs on 24-hour Holter monitoring, but the Pickelhaube sign and presence of myxomatous mitral valve may help to detect patients prone to significant VAs. Myocardial fibrosis can be detected by cardiac magnetic resonance in children with significant VAs.

Congenital Mitral Regurgitation Repair Based on Carpentier's Classification: Long-Term Outcomes

BACKGROUND

There are few reports of the outcomes of standardized surgical management addressing the etiologic and morphologic aspects of mitral valve malformation according to Carpentier's classification. This study aimed to evaluate the long-term outcomes of mitral valve repair in children according to Carpentier's classification.

METHODS

Patients who underwent mitral valve repair at our institution between 2000 and 2021 were retrospectively reviewed. Preoperative data, surgical techniques, and outcomes were analyzed according to Carpentier's classification. The proportion of patients free of mitral valve replacement and reoperation was estimated using Kaplan-Meier analysis.

RESULTS

Twenty-three patients (median operative age, four months) were followed up for 10 (range, 2-21) years. Preoperative mitral regurgitation was severe in 12 patients and moderate in 11 patients. Eight, five, seven, and three patients had Carpentier's type 1, 2, 3, and 4 lesions, respectively. Ventricular septal defect (N = 9) and double outlet of the great arteries from the right ventricle (N = 3) were the most commonly associated cardiac malformations. There were no cases of operative mortality or deaths during the follow-up. The overall five-year rate of freedom from mitral valve replacement was 91%, whereas the five-year rates of freedom from reoperation were 74%, 80%, 71%, and 67% in type 1, 2, 3, and 4 lesions, respectively. Postoperative mitral regurgitation at the last follow-up was moderate in three patients and less than mild in 20 patients.

CONCLUSIONS

Current surgical management of congenital mitral regurgitation is generally considered adequate; however, more complicated cases required a combination of various surgical techniques.

Surgical Results of Mitral Valve Repair for Mitral Regurgitation in Pediatric Patients with Mitral Valve Prolapse

The rare incidence of mitral regurgitation (MR) caused by mitral valve prolapse in children lacks clinical management experience. In this study, we present our experience in surgical management and the difference between isolated anterior mitral leaflet (AML), posterior mitral leaflet (PML), and bileaflet prolapse in pediatric patients. Between January 2014 and February 2021, 52 pediatric patients, aged 7.04 ± 4.02 years (ranged from 0.17 to 14 years), were diagnosed as moderately severe (11, 21.2%) or severe (41, 78.8%) MR, of which, 34 (65.4%) were owing to AML prolapse, one (1.9%) was PML prolapse, and 17 (32.7%) caused by bileaflet prolapse. All had received mitral valve repair, and were divided into the group of AML prolapse and bileaflet prolapse. Demographic and clinical characteristics of all patients were retrospectively collected and analyzed. The left ventricular diameter in the bileaflet group was significantly larger than the AML group (4.04 ± 0.73 cm vs. 3.45 ± 0.75 cm, P = 0.026). The median follow-up time was 33 months (ranged from 6 to 88 months). The postoperative and follow-up results had no significant difference between two groups. And only 2 patients received reoperation due to posterior annuloplasty ring dehiscence. For pediatric patients, the majority of the patients had isolated AML prolapse instead of PML prolapse. There was no difference in recurrent regurgitation or reoperation between isolated AML and bileaflet prolapse after MV repair, and we suggest more aggressive surgical strategy should be considered in pediatric patients with bileaflet prolapse than AML prolapse.

Anomalous left atrial chorda and its association with mitral regurgitation

Anomalous left atrial chorda is associated with mitral regurgitation. A young woman presenting for mitral valve repair with the diagnosis of mid-segment (A2) of anterior mitral leaflet prolapse causing severe mitral regurgitation. Transesophageal echocardiography examination in pre-bypass period showed an anomalous chorda attaching A2 to the left atrial roof, tethering the anterior mitral leaflet toward the atrial wall. Surgical findings confirmed the abnormally attached chordae and an absence of normal chorda of A2 segment. The anomalous chorda was resected and neo-chordae placed between the A2 segment and papillary muscles and annulus strengthened with an annuloplasty ring.

Cardiac forces regulate zebrafish heart valve delamination by modulating Nfat signaling

In the clinic, most cases of congenital heart valve defects are thought to arise through errors that occur after the endothelial–mesenchymal transition (EndoMT) stage of valve development. Although mechanical forces caused by heartbeat are essential modulators of cardiovascular development, their role in these later developmental events is poorly understood. To address this question, we used the zebrafish superior atrioventricular valve (AV) as a model. We found that cellularized cushions of the superior atrioventricular canal (AVC) morph into valve leaflets via mesenchymal–endothelial transition (MEndoT) and tissue sheet delamination. Defects in delamination result in thickened, hyperplastic valves, and reduced heart function. Mechanical, chemical, and genetic perturbation of cardiac forces showed that mechanical stimuli are important regulators of valve delamination. Mechanistically, we show that forces modulate Nfatc activity to control delamination. Together, our results establish the cellular and molecular signature of cardiac valve delamination in vivo and demonstrate the continuous regulatory role of mechanical forces and blood flow during valve formation.

Why do developing zebrafish atrioventricular heart valves become hyperplastic under certain hemodynamic conditions? This study suggests that part of the answer lies in how the mechanosensitive Nfat pathway regulates the valve mesenchymal-to-endothelial transition.

Comprehensive left ventricular outflow tract management beyond septal reduction to relieve obstruction

The surgical management of patients with hypertrophic obstructive cardiomyopathy can be extremely challenging. Relieving the left ventricular outflow tract obstruction in these patients is often achieved by performing a septal myectomy. However, in many instances, septal reduction alone is not enough to relieve the obstruction. Interventions on the sub-valvular apparatus, including the anomalous chordae tendineae and the abnormal papillary muscles, are often required. In this review, we summarize the embryology and the pathophysiology of the different elements that may contribute to the left ventricular outflow tract obstruction in the setting of hypertrophic obstructive cardiomyopathy. In addition, we highlight the different surgical procedures that a surgeon may adopt to relieve the left ventricular outflow tract obstruction, beyond the septal myectomy.

Undifferentiated Chordae Tendineae of the Mitral Valve: Large Cohort Study of a Rare Mitral Malformation

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.

Valvular heart disease in congenital heart disease: a narrative review

Patients with congenital heart disease (CHD) are one of the fastest growing populations in cardiology, and valvular pathology is at the center of many congenital lesions. Derangements in valvular embryology lead to several anomalies prone to dysfunction, each with hemodynamic effects that require appropriate surveillance and management. Surgical innovation has provided new treatments that have improved survival in this population, though has also contributed to esotericism in patients who already have unique anatomic and physiologic considerations. Conduit and prosthesis durability are often monitored collaboratively with general and specialized congenital-focused cardiologists. As such, general cardiologists must become familiar with valvular disease with CHD for appropriate care and referral practices. In this review, we summarize the embryology of the semilunar and atrioventricular (AV) valves as a foundation for understanding the origins of valvular CHD and describe the mechanisms that account for heterogeneity in disease. We then highlight the categories of pathology from the simple (e.g., bicuspid aortic valve, isolated pulmonic stenosis) to the more complex (e.g., Ebstein's anomaly, AV valvular disease in single ventricle circulations) with details on natural history, diagnosis, and contemporary therapeutic approaches. Care for CHD patients requires collaborative effort between providers, both CHD-specialized and not, to achieve optimal patient outcomes.

Impact of cleft-like indentations on procedural outcome of percutaneous edge-to-edge mitral valve repair

OBJECTIVES AND BACKGROUND

Percutaneous edge-to-edge mitral valve (MV) repair (PMVR) is broadly applied in high-risk patients with relevant mitral regurgitation (MR). We investigated the incidence of cleft-like indentations (CLI) and their impact on PMVR.

METHODS AND RESULTS

In a retrospective single center analysis including 263 patients undergoing PMVR with the MitraClip®-system between 11/2012 and 7/2016, MV anatomy was assessed by 3-dimensional transesophageal echocardiography. CLI were present in 37/263 patients (14.1%). Of these, 62.2% had 1 CLI, 27% had 2 CLI, and 10.8% had 3 CLI, mostly concerning segment P2 or P2/3 of the MV. Baseline characteristics were similarly distributed. Interestingly, most patients with CLI suffered from secondary MR (n = 29, 78%). The number of deployed MitraClips was higher in patients with CLI (2 [1.25-2] vs. 2 [1, 2], p = .035), whereas procedural as well as clinical success was similar: MR grade (1.2 vs. 1.5, p = .061), vena contracta width (4.2 vs. 4.5 mm, p = .293), dPmean (4.2 vs. 4.0 mmHg, p = .618) at discharge and NYHA class at 30 days did not differ between groups. Periprocedural complications were rare and equally distributed between groups. At 30 days, MR reduction persisted in patients with CLI (95.8% of these selected patients had a MR grade ≤ 2).

CONCLUSIONS

CLI of the MV are common in patients undergoing PMVR, also when presenting mainly with secondary MR. While the number of clips needed to address MR is slightly higher in patients with CLI, procedural success rates appear not to be affected. PMVR seems to be a safe treatment option for patients with CLI.

Surgical repair of mitral valve bileaflet prolapse in pediatric patients

BACKGROUND

Pediatric mitral regurgitation (MR), especially with bileaflet prolapse, is relatively rare, of high complexity, and frequently associated with other congenital cardiac abnormalities. It remains a major therapeutic challenge for surgeons. This study reports our experience of surgical treatment of this mitral disease and midterm follow-up results.

METHODS

Between January 2016 and April 2020, nine pediatric patients, six females and three males, age ranged from 3 to 12 years (median age was 6 years) with a weight range of 12-36 kg (median weight was 25 kg), who all had over moderate regurgitation caused by bileaflet prolapse with mean distance of leaflet coaptation beyond annular plane 5.89 ± 1.66 mm (4-9 mm), received mitral valve (MV) repair. Various surgical techniques were used to repair MV.

RESULTS

The median follow-up period was 23(6-51) months, only one patient had moderately severe recurrent of MR, no patient developed systolic anterior motion (SAM) or mitral stenosis. Freedom from reoperation was 100% during the follow-up period. Compared to preoperation, the left atrial (LA) diameter and left ventricular end-diastolic diameter (LVEDD) decreased significantly from 2.94 ± 0.49 cm to 2.37 ± 0.38 cm (LA, p < .01) and from 4.13 ± 0.73 cm to 3.62 ± 0.49 cm (LVEDD, p < .01) respectively, ejection fraction (EF) decreased significantly (p < .05) from 68.56 ± 3.98% to 62.89 ± 4.48% before discharged.

CONCLUSION

We share our experience of surgical repair of mitral valve bileaflet prolapse in pediatric patients. Several surgical methods are considered to be used to repair the MV due to the high complexity of lesions. Anatomic correction or functional correction in our reports almost reaches the same result, while functional correction means simpler operation.

Isolated Congenital Mitral Regurgitation Repair in Children: Long-term Outcomes of Artificial Rings

BACKGROUND

Because isolated congenital mitral regurgitation (ICMR) is rare, the role of artificial rings in annuloplasty for ICMR is still debated. In this study we compared long-term results of annuloplasty with and without rings for ICMR.

METHODS

We performed a retrospective review of all patients ≤ 18 years old undergoing repair for ICMR from 1993 to 2019 at our hospital. Techniques of annuloplasty depended on individual lesions of the mitral valve (MV). One hundred twelve cases were divided into 3 groups: group A (43 cases) with ≥26-mm ring, group B (35 cases) with <26-mm ring, and group C (34 cases) with a band. Study endpoints were overall survival and MV reoperation.

RESULTS

Patients in group A were older than the others (median age 11 compared with 5 and 4 years, respectively). The MV lesions were complicated, but annular dilatation existed in 91% of cases. Three patients died, and there were 25 reoperations during a median follow-up period of 11 years. Groups B and C had higher rates of reoperation than group A (hazard ratios, 5.35 [95% confidence interval, 1.71-17.75] and 3.61 [95% confidence interval, 1.03-12.60], respectively). Most reoperations in group B (13/14 cases) were due to stenosis, whereas 6 of 7 reoperations in group C were due to recurrent regurgitation.

CONCLUSION

MV reconstruction for ICMR in children had good long-term survival. Annuloplasty with ≥26-mm ring had the lowest risk of reoperation. In cases of young children bands are more favored than <26-mm rings, but they carry a risk of recurrent regurgitation.

Double orifice and atrioventricular septal defect: dealing with the zone of apposition†

OBJECTIVES

A double orifice of the left atrioventricular valve (LAVV) associated with atrioventricular septal defects (AVSD) can significantly complicate surgical repair. This study reports our experience of AVSD repair over 3 decades, with special attention to the zone of apposition (ZoA) of the main orifice, and presents a technique of hemivalve pericardial extension in specific situations.

METHODS

We performed a retrospective study from 1987 to 2016 on 1067 patients with AVSD of whom 43 (4%) had a double orifice, plus 2 additional patients who required LAVV pericardial enlargement. Median age at repair was 1.3 years. Mean follow-up was 8.2 years (1 month-32 years).

RESULTS

Associated abnormalities of the LAVV subvalvular apparatus were found in 7 patients (5 parachute LAVV and 2 absence of LAVV subvalvular apparatus). ZoA was noted in 4 patients (9%): partially closed in 15 (35%) and completely closed in 24 (56%). Four patients required, either at first repair or secondarily, a hemivalve enlargement using a pericardial patch without closure of the ZoA. The early mortality rate was 7% (n = 3), all before 2000. Two patients had unbalanced ventricles and the third had a single papillary muscle. There were no late deaths. Six patients (14%) required 7 reoperations (3 early and 4 late reoperations) for LAVV regurgitation and/or dysfunction, of whom 4 (9%) required mechanical LAVV replacement (all before 2000). Freedom from late LAVV reoperation was 97% at 1 year, 94% at 5 years and 87% at 10, 20 and 30 years. Unbalanced ventricles (P = 0.045), subvalvular abnormalities (P = 0.0037) and grade >2 LAVV postoperative regurgitation (P = 0.017) were identified as risk factors for LAVV reoperations. Freedom from LAVV mechanical valve replacement was 95% at 1 year, 90% at 5 years and 85% at 10, 20 and 30 years. An anomalous LAVV subvalvular apparatus was identified as a risk factor for mechanical valve replacement (P = 0.010). None of the patients who underwent LAVV pericardial extension had significant LAVV regurgitation at the last follow-up examination.

CONCLUSIONS

Repair of AVSD and double orifice can be tricky. Preoperative LAVV regurgitation was not identified as an independent predictor of surgical outcome. LAVV hemivalve extension appears to be a useful and effective alternate surgical strategy when the ZoA cannot be closed.

Surgical Repair of a Unileaflet Mitral Valve: A Rare Congenital Abnormality and a Novel Surgical Approach

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The authors report a novel approach for MV repair.

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ULMV is rare in clinical practice.

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Comprehensive multimodality cardiac imaging can delineate complex valvular pathology.

An Unusual Cause of Stroke in a Young Adult

Stroke is an uncommon presentation in young adults, with different causes and risks factors implicated. Cardiogenic cerebral embolus is one of the most common causes in younger patients and must be considered in the investigation of young patients presenting with stroke. The authors describe a case of a young patient presenting with stroke as a result of distal embolization from a previously undiagnosed congenital mitral valve defect.

Parachute mitral valve: Morphology and surgical management

Background

This review aims to discuss morphology and surgical management of parachute mitral valve.

Methods

A total of 62 articles in the English language with 330 parachute mitral valve patients were retrieved from the PubMed, HighWire Press, and Cochrane Library databases using specific MeSH terms and keywords between January 2000 and December 2018. In these articles, morphology of parachute mitral valve and surgical treatment options were investigated.

Results

A non-syndromic parachute mitral valve was present in 287 patients (87.0%) and a syndromic parachute mitral valve was present in 43 patients (13.0%). A higher number of patients with a non-syndromic parachute mitral valve presented with congestive heart failure compared to syndromic ones. The patients with a non-syndromic parachute mitral valve often had mitral regurgitation, while syndromic parachute mitral valve patients often had mitral stenosis.

Conclusion

Parachute mitral valves are usually not an isolated lesion and are often characterized by a constellation of pathological changes of the mitral valve leaflets, annulus, commissures, subvalvular apparatus, and supravalvular mitral ring. Therefore, the majority of the patients need one or more surgical operations. The incidence of adverse events such as reintervention, postoperative complete heart block, and mortality is high in these patients.

Echocardiographic examination of mitral valve abnormalities in the paediatric population: current practices

We reviewed the recent literature for echocardiographic assessment of mitral valve abnormalities in children. A literature search was performed within the National Library of Medicine using the keywords "mitral regurgitation and/or stenosis, children." The search was refined by adding the keywords "echocardiographic definition, classification, and evaluation." Thirty-one studies were finally included. Significant advances in echocardiographic imaging of mitral valve defects, mainly due to the implementation of three-dimensional technology, contribute to a better understanding of the underlying anatomy. However, heterogeneity between classification systems of mitral valve disease severity is a serious problem. For regurgitant lesions, there is only very limited evidence from small studies that support the adoption of quantitative/semi-quantitative indexes commonly employed in adults. Despite the lack of evidence base, qualitative evaluation of regurgitation severity is often employed. For stenotic lesions, no clear categorisation based on trans-valvular echocardiography-derived "gradients" has been consistently applied to define mild, moderate, or severe obstruction across different paediatric age ranges. Quantitative parameters such as valve area have also been poorly validated in children. Adult recommendations are frequently applied without validation for the paediatric age. In conclusion, significant advances in the anatomical evaluation of mitral valve diseases have been made, thanks to three-dimensional echocardiography; however, limitations remain in the quantitative/semi-quantitative estimation of disease severity, both with respect to valvular regurgitation and stenosis. Because adult echocardiographic recommendations should not be simply translated to the paediatric age, more specific paediatric guidelines and standards for the assessment of mitral valve diseases are needed.

Isolated adult congenital uni-leaflet severe mitral valve stenosis, a case report, and review of literature

Reported cases of uni-leaflet mitral valve (MV) were related to the absence or dysplasia of the posterior mitral leaflet with ample anterior mitral leaflet. We present here a new entity of uni-leaflet MV where the MV appears as a membrane-like structure with a single slit-like orifice at its lateral part with no commissures.

Case report

Continuous Doppler flow revealed a mean pressure gradient of 19 mmHg across the mitral valve indicating severe mitral stenosis. In 3D images from the left atrial view, the MV appeared like a membrane with a single orifice in its lateral part toward the left atrial appendage, the area of this orifice by 3D was 0.52 cm², there were no commissures or even any residual lines at the site where commissures should be. The diagnosis of congenital severe mitral stenosis due to acommissural MV was confirmed. During surgery, the surgical appearance of the MV confirmed our diagnosis by 3D.

Conclusion

Isolated congenital severe mitral stenosis presenting in adulthood is rare, uni-leaflet MV as a cause is only reported in a few cases. MV replacement is usually indicated due to the abnormal anatomy of MV leaflets and the subvalvular apparatus.<Learning objectives: How to diagnose uni-leaflet congenital mitral stenosis and how to differentiate it from other causes of congenital mitral stenosis.>.

Design and evaluation of the crimping of a hooked self-expandable caval valve stent for the treatment of tricuspid regurgitation

To design a hooked self-expandable caval valve stent and determine the best crimping scenario for its percutaneous implantation in the Superior and Inferior Vena Cava (SVC & IVC) for the treatment of tricuspid regurgitation (TR). A hooked, Nitinol based stent design was modeled using SOLIDWORKS and finite element analysis (FEA) was carried out using ABAQUS. The Nitinol material used in this study was modeled in ABAQUS as superelastic-plastic. Two cases were simulated. In case A, the stent model was crimped to 18 F by compressing the stent main body and then: (i) bending both the proximal and distal hooks; (ii) straightening the proximal hooks and bending the distal hooks. In case B, the stent model was crimped to 18 F by: (i) bending the proximal and distal hooks and then compressing the stent main body; (ii) straightening the proximal hooks and bending the distal hooks and then compressing the stent main body. The maximum strain after crimping was used to evaluate the best crimping scenario. Hook straightening produced strains of 10.7% and 10.96% as opposed to 12.6% and 13.0% produced by hook bending. From comparison of results of both cases simulated, it was found that straightening the hooks gave lower strain and thus was the best crimping procedure. The analysis performed in this paper may help understand the critical issue of crimpability of the new stent design. The best crimping scenario can be found based on finite element modeling and simulation. Identifying the best crimping way will also help the design team to optimize the delivery system that will eventually be used to deploy this caval valve stent.

Hammock Mitral Valve Repair in Infancy: Operative Steps Toward a Customized Reconstruction After Preoperative Planning

Hammock mitral valve (MV) repair is historically technically difficult with a guarded prognosis. Surgical experience is extremely limited and variable outcomes are reported. The perioperative strategy and technical details of hammock MV repair in an infant who presented with severe mitral stenosis are described and review of the existing literature was undertaken.

An unusual appearance of a large mitral valve cleft within a prolapsing segment diagnosed by three-dimensional transesophageal echocardiography

Eighty-year-old woman presented for minimally invasive mitral valve repair for severe mitral regurgitation. Intraoperative two-dimensional transesophageal echocardiography (2DTEE) and subsequent three-dimensional transesophageal echocardiography examination showed severe mitral valve regurgitation with a bidirectional jet caused by both P2 segment prolapse and a large cleft within the P2 segment. The preoperative diagnosis of this complex pathology was challenging by 2DTEE, and a 3D examination of the mitral valve was helpful to confirm the presence of a cleft within the prolapsing segment.

Starfish in the heart: Congenital anomaly of the papillary muscles

Most common congenital anatomical abnormalities of the subvalvular apparatus (papillary muscles and chordae tendineae) are parachute or parachute like mitral valve. This is more commonly reported among the pediatric population as they develop heart failure symptoms shortly after birth. Reports of adult cases are rare and incidental. Multimodality imaging has an important role in evaluating such anatomical abnormalities, and identification of possible related complications. We are describing a rare atypical variant of parachute like mitral valve.

The Challenge of Hammock Mitral Valve During Infancy: Precise Preoperative Advanced Imaging and Three-Dimensional Modeling Augments Customized Operative Valve Reconstruction

Hammock mitral valve (MV), also known as anomalous mitral arcade, is a rare congenital anomaly. We report a case of a 10-month-old child who presented with congestive heart failure and was found to have severe mitral stenosis (MS) secondary to a hammock MV anomaly. Detailed advanced imaging with cardiac MRI and three-dimensional (3D) echocardiography favorably navigated a customized valve-sparing surgical reconstruction of the congenitally abnormal MV. Repair of a hammock MV is technically difficult with a guarded prognosis. Surgical experience is extremely limited and variable outcomes are reported. A rare case of severe MS secondary to hammock MV deformity with successful surgical repair and review of worldwide literature are presented.

Mitral Hemi-Arcade: A Rare Variant of a Rare Disease

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A case of a healthy young male with chest pain and borderline electrocardiogram is presented.

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Imaging showed a mitral hemi-arcade with left ventricular outflow tract obstruction during exercise.

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Previously postulated mechanisms for this obstruction are reviewed in this article.

Design and Development of Novel Transcatheter Bicaval Valves in the Interventional Treatment of Tricuspid Regurgitation

The concept of heterotopic implantation of transcatheter tricuspid valve is new and has shown promising results thus far. While the Reynolds shear stress values measured in the vicinity of this valve are relatively low, the values at some time points are higher than the threshold of platelet activation. Hence, in this study, we aim to reduce these values with an innovative stent design. It was shown that the Reynolds shear stress values measured were lower than those of valves made of generic stent design and the maximum Reynolds shear stress values in the vicinity of the valves was very low (∼10 dynes/cm² ). The results also depicted the interesting flow phenomenon of this non-physiological treatment approach. Thus, this study has shown that bicaval valves could potentially be considered as a minimally invasive option to treat tricuspid regurgitation and valve design improvements could reduce the flow disturbances that were observed.

Morphological three-dimensional analysis of papillary muscles in borderline left ventricles

OBJECTIVE

Mitral valve anatomy has a significant impact on potential surgical options for patients with hypoplastic or borderline left ventricle. Papillary muscle morphology is a major component regarding this aspect. The purpose of this study was to use cardiac magnetic resonance to describe the differences in papillary muscle anatomy between normal, borderline, and hypoplastic left ventricles.

METHODS

We carried out a retrospective, observational cardiac magnetic resonance study of children (median age 5.36 years) with normal (n=30), borderline (n=22), or hypoplastic (n=13) left ventricles. Borderline and hypoplastic cases had undergone an initial hybrid procedure. Morphological features of the papillary muscles, location, and arrangement were analysed and compared across groups.

RESULTS

All normal ventricles had two papillary muscles with narrow pedicles; however, 18% of borderline and 46% of hypoplastic cases had a single papillary muscle, usually the inferomedial type. In addition, in borderline or hypoplastic ventricles, the supporting pedicle occasionally displayed a wide insertion along the ventricular wall. The length ratio of the superolateral support was significantly different between groups (normal: 0.46±0.08; borderline: 0.39±0.07; hypoplastic: 0.36±0.1; p=0.009). No significant difference, however, was found when analysing the inferomedial type (0.42±0.09; 0.38±0.07; 0.39±0.22, p=0.39). The angle subtended between supports was also similar among groups (113°±17°; 111°±51° and 114°±57°; p=0.99). A total of eight children with borderline left ventricle underwent biventricular repair. There were no significant differentiating features for papillary muscle morphology in this subgroup.

CONCLUSIONS

The superolateral support can be shorter or absent in borderline or hypoplastic left ventricle cases. The papillary muscle pedicles in these patients often show a broad insertion. These changes have important implications on surgical options and should be described routinely.

Effect of altered haemodynamics on the developing mitral valve in chick embryonic heart

Intracardiac haemodynamics is crucial for normal cardiogenesis, with recent evidence showing valvulogenesis is haemodynamically dependent and inextricably linked with shear stress. Although valve anomalies have been associated with genetic mutations, often the cause is unknown. However, altered haemodynamics have been suggested as a pathogenic contributor to bicuspid aortic valve disease. Conversely, how abnormal haemodynamics impacts mitral valve development is still poorly understood. In order to analyse altered blood flow, the outflow tract of the chick heart was constricted using a ligature to increase cardiac pressure overload. Outflow tract-banding was performed at HH21, with harvesting at crucial valve development stages (HH26, HH29 and HH35). Although normal valve morphology was found in HH26 outflow tract banded hearts, smaller and dysmorphic mitral valve primordia were seen upon altered haemodynamics in histological and stereological analysis at HH29 and HH35. A decrease in apoptosis, and aberrant expression of a shear stress responsive gene and extracellular matrix markers in the endocardial cushions were seen in the chick HH29 outflow tract banded hearts. In addition, dysregulation of extracellular matrix (ECM) proteins fibrillin-2, type III collagen and tenascin were further demonstrated in more mature primordial mitral valve leaflets at HH35, with a concomitant decrease of ECM cross-linking enzyme, transglutaminase-2. These data provide compelling evidence that normal haemodynamics are a prerequisite for normal mitral valve morphogenesis, and abnormal blood flow could be a contributing factor in mitral valve defects, with differentiation as a possible underlying mechanism.

Congenital uni-leaflet mitral valve with severe stenosis: A case report with literature review

Numerical abnormalities of mitral leaflets is a special entity in congenital mitral malformations. Previously reported cases of uni-leaflet mitral valve were primarily related to absence or dysplasia of certain leaflets. We present a case here with mitral leaflets that were not divided into anterior and posterior as usual, but developed as an integral structure instead, which is different from previously documented cases of uni-leaflet mitral valves. Real time three-dimensional echocardiography (RT3DE) provides a visual presentation of the abnormal mitral structure which was confirmed by surgical operation. To the best of our knowledge, this unusual form of uni-leaflet mitral valve has not been reported yet.

Severe mitral regurgitation due to an extraordinary heart defect

A previously non-described cause of mitral regurgitation is presented. An asymptomatic 50-year old male who was casually diagnosed of mitral valve Barlow's disease underwent cardiac surgery due to severe mitral regurgitation. In the operating theatre, a longitudinal fissure of 1.5-2.0 cm length, along the posterior mitral leaflet, was found responsible for the insufficiency. This defect had features of a potential congenital origin and it was successfully repaired with direct suture. Whether it is an atypical mitral cleft, a variation of Barlow's morphology spectrum or a new congenital heart defect remains unclear.

Bands, Chords, Tendons, and Membranes in the Heart: An Imaging Overview

Crests, bands, chords, and membranes can be seen within the different cardiac chambers, with variable clinical significance. They can be incidental or can have clinical implications by causing hemodynamic disturbance. It is crucial to know the morphology and orientation of normal structures, aberrant or accessory muscles, and abnormal membranes to diagnose the hemodynamic disturbance associated with them. Newer generation computed tomographic scanners and faster magnetic resonance imaging sequences offer high spatial and temporal resolution allowing for acquisition of high resolution images of the cardiac chambers improving identification of small internal structures, such as papillary muscles, muscular bands, chords, and membranes. They also help in identification of other associated complications, malformations, and provide a road map for treatment. In this article, we review cross-sectional cardiac imaging findings of normal anatomical variants and distinctive imaging features of pathologic bands, chords, or membranes, which may produce significant hemodynamic changes and clinical symptomatology.