Clinical significance of the bicuspid aortic valve

Aneurysm development in patients with a bicuspid aortic valve is not associated with transforming growth factor-β activation

OBJECTIVE

Patients with bicuspid aortic valve (BAV) have an increased risk of developing ascending aortic aneurysms. Transforming growth factor-β (TGFβ) is a crucial factor of vascular remodeling, the impaired signaling of which can alter the structure and composition of the extracellular matrix. In this study, we analyzed the activity of TGFβ in aneurysmal and nonaneurysmal ascending aorta from BAV patients, using tricuspid aortic valve (TAV) patients as a reference group.

APPROACH AND RESULTS

The response to exogenous TGFβ was analyzed with regard to gene expression in primary aortic smooth muscle cells that were isolated from 7 BAV and 5 TAV patients and in valve fibroblasts from 7 BAV and 8 TAV patients. The set of genes that were significantly changed by TGFβ (217 genes) was compared with gene expression profiles of the ascending aorta from BAV and TAV patients (139 arrays). By principle component analysis, based on the 217 genes, gene expression differed significantly in the intima/media region between aneurysmal BAV and TAV aortas, driven by the response in TAV patients. During aneurysm development the levels of phosphorylated SMADs and the availability of free TGFβ were lower in BAV patients compared with TAV. Confocal microscopy analysis showed a higher colocalization of latency associated peptide and latent TGFβ binding protein 3 in BAV aortas.

CONCLUSIONS

Our findings suggest that TGFβ activation during aneurysm formation is muted in patients with BAV, possibly as a result of an increased TGFβ sequestration in the extracellular space.

The stretch responsive microRNA miR-148a-3p is a novel repressor of IKBKB, NF-κB signaling, and inflammatory gene expression in human aortic valve cells

Bicuspid aortic valves calcify at a significantly higher rate than normal aortic valves, a process that involves increased inflammation. Because we have previously found that bicuspid aortic valve experience greater stretch, we investigated the potential connection between stretch and inflammation in human aortic valve interstitial cells (AVICs). Microarray, quantitative PCR (qPCR), and protein assays performed on AVICs exposed to cyclic stretch showed that stretch was sufficient to increase expression of interleukin and metalloproteinase family members by more than 1.5-fold. Conditioned medium from stretched AVICs was sufficient to activate leukocytes. microRNA sequencing and qPCR experiments demonstrated that miR-148a-3p was repressed in both stretched AVICs (43% repression) and, as a clinical correlate, human bicuspid aortic valves (63% reduction). miR-148a-3p was found to be a novel repressor of IKBKB based on data from qPCR, luciferase, and Western blot experiments. Furthermore, increasing miR-148a-3p levels in AVICs was sufficient to decrease NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) signaling and NF-κB target gene expression. Our data demonstrate that stretch-mediated activation of inflammatory pathways is at least partly the result of stretch-repression of miR-148a-3p and a consequent failure to repress IKBKB. To our knowledge, we are the first to report that cyclic stretch of human AVICs activates inflammatory genes in a tissue-autonomous manner via a microRNA that regulates a central inflammatory pathway.

Transcatheter Aortic Valve Implantation (TAVI) in Patients With Bicuspid Aortic Valve Stenosis--Systematic Review and Meta-Analysis

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is a feasible interventional technique for severe aortic stenosis in patients who are deemed inoperable or at high surgical risk. There is limited evidence for the safety and efficacy of TAVI in patients with bicuspid aortic valves (BAV), the most common congenital valve abnormality. In many TAVI trials, patients with BAV have been contraindicated due to concerns surrounding abnormal valve geometry, leading to malfunction or malpositioning. A systematic review and meta-analysis was conducted in order to assess the current evidence and relative merits of TAVI in aortic stenosis patients with BAV.

METHOD

From six electronic databases, seven articles including 149 BAV and 2096 non-BAV patients undergoing TAVI were analysed.

RESULTS

Between the BAV and no-BAV cohorts, there was no difference in 30-day mortality (8.3% vs 9.0%; P=0.68), post-TAVI mean peak gradients (weighted mean difference, 0.36 mmHg; P=0.55), moderate or severe paravalvular leak (25.7% vs 19.9%; P=0.29), pacemaker implantations (18.5% vs 27.9%; P=0.52), life-threatening bleeding (8.2% vs 13.9%; P=0.33), major bleeding (20% vs 16.8%; P=0.88), conversion to conventional surgery (1.9% vs 1.2%; P=0.18) and vascular complications (8.6% vs 10.1%; P=0.32).

CONCLUSIONS

Preliminary short and mid-term pooled data from observation studies suggest that TAVI is feasible and safe in older patients with BAV. While future randomised trials are not likely, larger adequately-powered multi-institutional studies are warranted to assess the long-term durability and complications associated with TAVI in older BAV patients with severe aortic stenosis.

Aortic valve reconstruction with use of pericardial leaflets in adults with bicuspid aortic valve disease: early and midterm outcomes

In this study, we retrospectively analyzed the outcomes of adults with bicuspid aortic valve (BAV) disease who underwent aortic valve reconstructive surgery (AVRS), consisting of replacement of the diseased BAV with 2 or 3 pericardial leaflets plus fixation of the sinotubular junction for accurate and constant leaflet coaptation. From December 2007 through April 2013, 135 consecutive patients (mean age, 49.2 ± 13.1 yr; 73.3% men) with symptomatic BAV disease underwent AVRS. Raphe was observed in 84 patients (62.2%), and the remaining 51 patients had pure BAV without raphe. A total of 122 patients (90.4%) underwent 3-leaflet reconstruction, and 13 (9.6%) underwent 2-leaflet reconstruction. Concomitant aortic wrapping with an artificial graft was performed in 63 patients (46.7%). There were no in-hospital deaths and 2 late deaths (1.5%); 6 patients (4.4%) needed valve-related reoperation. The 5-year cumulative survival rate was 98% ± 1.5%, and freedom from valve-related reoperation at 5 years was 92.7% ± 3.6%. In the last available echocardiograms, aortic regurgitation was absent or trivial in 116 patients (85.9%), mild in 16 (11.9%), moderate in 2 (1.5%), and severe in one (0.7%). The mean aortic valve gradient was 10.2 ± 4.5 mmHg, and the mean aortic valve orifice area index was 1.3 ± 0.3 cm(2)/m(2). The 3-leaflet technique resulted in lower valve gradients and greater valve areas than did the 2-leaflet technique. Thus, in patients with BAV, AVRS yielded satisfactory early and midterm results with low mortality rates and low reoperation risk after the initial procedure.

Genetics of valvular heart disease

Valvular heart disease is associated with significant morbidity and mortality and often the result of congenital malformations. However, the prevalence is increasing in adults not only because of the growing aging population, but also because of improvements in the medical and surgical care of children with congenital heart valve defects. The success of the Human Genome Project and major advances in genetic technologies, in combination with our increased understanding of heart valve development, has led to the discovery of numerous genetic contributors to heart valve disease. These have been uncovered using a variety of approaches including the examination of familial valve disease and genome-wide association studies to investigate sporadic cases. This review will discuss these findings and their implications in the treatment of valvular heart disease.

The Role of Multimodality Cardiac Imaging for the Assessment of Sports Eligibility in Patients with Bicuspid Aortic Valve

Bicuspid aortic valve (BAV) cannot be considered an innocent finding, but it is not necessarily a life-threatening condition. Athletes with BAV should undergo a thorough staging of the valve anatomy, taking into consideration hemodynamic factors, as well as aortic diameters and looking for other associated significant cardiovascular anomalies by use of a multimodality cardiac imaging approach. Furthermore an accurate follow-up is mandatory with serial cardiological controls in those allowed to continue sports.

Etiology of bicuspid aortic valve disease: Focus on hemodynamics

The bicuspid aortic valve (BAV) is the most common form of inheritable cardiac defect. Although this abnormality may still achieve normal valvular function, it is often associated with secondary valvular and aortic complications such as calcific aortic valve disease and aortic dilation. The clinical significance and economic burden of BAV disease justify the need for improved clinical guidelines and more robust therapeutic modalities, which address the root-cause of those pathologies. Unfortunately, the etiology of BAV valvulopathy and aortopathy is still a debated issue. While the BAV anatomy and its secondary complications have been linked historically to a common genetic root, recent advances in medical imaging have demonstrated the existence of altered hemodynamics near BAV leaflets prone to calcification and BAV aortic regions vulnerable to dilation. The abnormal mechanical stresses imposed by the BAV on its leaflets and on the aortic wall could be transduced into cell-mediated processes, leading ultimately to valvular calcification and aortic medial degeneration. Despite increasing evidence for this hemodynamic etiology, the demonstration of the involvement of mechanical abnormalities in the pathogenesis of BAV disease requires the investigation of causality between the blood flow environment imposed on the leaflets and the aortic wall and the local biology, which has been lacking to date. This editorial discusses the different hypothetical etiologies of BAV disease with a particular focus on the most recent advances in cardiovascular imaging, flow characterization techniques and tissue culture methodologies that have provided new evidence in support of the hemodynamic theory.

Late complication after repair of aortic coarctation

Background

Coarctation of the aorta is a congenital malformation that has long been considered completely correctable with appropriate surgery in childhood. However, with the aging of these patients, many late complications have been reported, and this notion must be reevaluated.

Methods

We retrospectively reviewed all patients who underwent reoperation between 1992 and 2012 in our adult cardiac surgery department following surgical correction of coarctation in childhood; 18 patients over 15-years old were included in the study.

Results

The median time from coarctation repair to reoperation was 25 years. Patients were reoperated on for several late complications: aortic valve disease secondary to bicuspid aortic valve, ascending aortic aneurysm, recoarctation, aortic arch hypoplasia, pseudoaneurysm, associated recoarctation and pseudoaneurysm, subvalvular aortic obstruction, and descending thoracic aortic aneurysm. One patient died due to an intraoperative complication. In the other cases, the surgical results were satisfactory at the 6-month follow-up. According to literature data, age at coarctation repair and surgical technique appear to be essential factors in late complications: older age and surgical repair with prosthesis interposition are associated with a higher rate of reintervention.

Conclusion

Patients who have undergone repair of aortic coarctation frequently remain asymptomatic for a long time. Late complications can be appropriately treated when diagnosed early. Consequently, all coarctation patients need careful lifelong follow-up, especially those with congenital aortic valve disease or surgery in childhood with interposition of prosthetic material.

Diagnosis and management of valvular aortic stenosis

Valvular aortic stenosis (AS) is a progressive disease that affects 2% of the population aged 65 years or older. The major cause of valvular AS in adults is calcification and fibrosis of a previously normal tricuspid valve or a congenital bicuspid valve, with rheumatic AS being rare in the United States. Once established, the rate of progression of valvular AS is quite variable and impossible to predict for any particular patient. Symptoms of AS are generally insidious at onset, though development of any of the three cardinal symptoms of angina, syncope, or heart failure portends a poor prognosis. Management of symptomatic AS remains primarily surgical, though transcatheter aortic valve replacement (TAVR) is becoming an accepted alternative to surgical aortic valve replacement (SAVR) for patients at high or prohibitive operative risk.

Carotid Plaque, Intima-Media Thickness, and Incident Aortic Stenosis

Objective—

Aortic stenosis (AS) shares risk factors with atherosclerotic vascular disease. Carotid intima-media thickness (IMT) and plaque may reflect the cumulative damage from exposure to different atherosclerotic risk factors. We examined the relationship of carotid IMT and plaque with incident AS in a prospective population-based study.

Approach and Results—

A random sample of participants (age, 45–68 years) in the population-based Malmö Diet and Cancer Study underwent B-mode ultrasound with measurements of IMT and the presence of plaque in the common carotid artery (n=5079). Potential risk factors for incident AS were studied in age- and sex-adjusted and expanded multivariable-adjusted Cox regression models. A total of 69 (1.4%) participants developed AS during up to 20 years of follow-up. Significant risk factors for AS in age- and sex-adjusted analyses were ( P <0.05) body mass index, low-density lipoprotein cholesterol, hypertension, diabetes mellitus, smoking, C-reactive protein, plaque, and IMT. In contrast, high-density lipoprotein cholesterol, triglycerides, height, and leukocyte count were not significantly associated with AS ( P >0.05). After adjustments, IMT, plaque, age, smoking, C-reactive protein, low-density lipoprotein cholesterol, and diabetes mellitus remained significantly associated with incident AS. IMT was no longer significantly associated with AS after adjustments for plaque and systolic blood pressure, but plaque remained significantly associated with incident AS.

Conclusions—

Traditional cardiovascular risk factors were individually associated with incident AS, and in multivariable models low-density lipoprotein cholesterol, smoking, age, presence of plaque, C-reactive protein, and diabetes mellitus remained significant predictors of incident AS. AS represents a vascular disorder related to carotid plaque, with potential implications for the pathophysiology and prevention of this disease.

Use of a targeted, combinatorial next-generation sequencing approach for the study of bicuspid aortic valve

Background

Bicuspid aortic valve (BAV) is the most common type of congenital heart disease with a population prevalence of 1-2%. While BAV is known to be highly heritable, mutations in single genes (such as GATA5 and NOTCH1) have been reported in few human BAV cases. Traditional gene sequencing methods are time and labor intensive, while next-generation high throughput sequencing remains costly for large patient cohorts and requires extensive bioinformatics processing. Here we describe an approach to targeted multi-gene sequencing with combinatorial pooling of samples from BAV patients.

Methods

We studied a previously described cohort of 78 unrelated subjects with echocardiogram-identified BAV. Subjects were identified as having isolated BAV or BAV associated with coarctation of aorta (BAV-CoA). BAV cusp fusion morphology was defined as right-left cusp fusion, right non-coronary cusp fusion, or left non-coronary cusp fusion. Samples were combined into 19 pools using a uniquely overlapping combinatorial design; a given mutation could be attributed to a single individual on the basis of which pools contained the mutation. A custom gene capture of 97 candidate genes was sequenced on the Illumina HiSeq 2000. Multistep bioinformatics processing was performed for base calling, variant identification, and in-silico analysis of putative disease-causing variants.

Results

Targeted capture identified 42 rare, non-synonymous, exonic variants involving 35 of the 97 candidate genes. Among these variants, in-silico analysis classified 33 of these variants as putative disease-causing changes. Sanger sequencing confirmed thirty-one of these variants, found among 16 individuals. There were no significant differences in variant burden among BAV fusion phenotypes or isolated BAV versus BAV-CoA. Pathway analysis suggests a role for the WNT signaling pathway in human BAV.

Conclusion

We successfully developed a pooling and targeted capture strategy that enabled rapid and cost effective next generation sequencing of target genes in a large patient cohort. This approach identified a large number of putative disease-causing variants in a cohort of patients with BAV, including variants in 26 genes not previously associated with human BAV. The data suggest that BAV heritability is complex and polygenic. Our pooling approach saved over $39,350 compared to an unpooled, targeted capture sequencing strategy.

Aortic vascular graft infection caused by Cardiobacterium valvarum: a case report

A 53-year-old man with a past medical history of total arch replacement surgery and severe aortic regurgitation presented with a 1-month history of persistent general malaise, anorexia, body weight loss and night sweats. His recent history included gingival hyperplasia for 6 years, gingivitis after tooth extraction 3 years before, prolonged inflammatory status for 4 months, fundal hemorrhage and leg tenderness for 2 months. A pathogen was detected from blood culture, but conventional microbiological examination failed to identify the pathogen. The organism was eventually identified as Cardiobacterium valvarum by 16S rRNA analysis, and the patient was diagnosed with infective endocarditis and prosthetic vascular graft infection. The patient received intravenous antibiotic therapy using a combination of ceftriaxone and levofloxacin for 5 weeks and was discharged with a good clinical course. C. valvarum is a rare human pathogen in clinical settings. Only 10 cases have been reported to date worldwide, and therefore, the clinical characteristics of C. valvarum infection are not fully known. This is a first well-described case of C. valvarum infection in Japan, and further, a first report of aortic prosthetic vascular graft infection worldwide. Identification of C. valvarum is usually difficult due to its phenotypic characteristics, and molecular approaches would be required for both clinicians and microbiologists to facilitate more reliable diagnosis and uncover its clinical picture more clearly.

Bicuspid aortic valves experience increased strain as compared to tricuspid aortic valves

OBJECTIVE

To determine whether the leaflets of bicuspid aortic valve (BAV) experience increased strain when compared to tricuspid aortic valve (TAV) leaflets.

BACKGROUND

The population at highest risk of aortic valve calcification (AVC) are individuals with BAVs. Currently, efforts to medically treat AVC are hampered by a limited understanding of the biomechanical forces involved in the molecular pathogenesis of AVC.

METHODS

Surgically created BAVs and control TAVs were placed into a left heart simulator. Strains were calculated by comparing the distances between points on the aortic valve (AoV) leaflet during various time points during a simulated cardiac cycle.

RESULTS

The fused leaflets of BAVs experience significantly more strain during systole when compared to TAVs. Specifically, BAVs experience 24% strain (P < .0001) in the radial direction, parallel to the direction of blood flow, as compared to TAVs. There was peak difference of 4% (P < .001) in the circumferential direction.

DISCUSSION

Based upon the data presented here, we are in the process of identifying how increased strain activates calcification-associated pathways in AoV cells. Future studies will examine whether these stretch responsive pathways can be blocked to inhibit calcification of BAVs.

Characterization of abnormal wall shear stress using 4D flow MRI in human bicuspid aortopathy

There exists considerable controversy surrounding the timing and extent of aortic resection for patients with BAV disease. Since abnormal wall shear stress (WSS) is potentially associated with tissue remodeling in BAV-related aortopathy, we propose a methodology that creates patient-specific 'heat maps' of abnormal WSS, based on 4D flow MRI. The heat maps were created by detecting outlier measurements from a volumetric 3D map of ensemble-averaged WSS in healthy controls. 4D flow MRI was performed in 13 BAV patients, referred for aortic resection and 10 age-matched controls. Systolic WSS was calculated from this data, and an ensemble-average and standard deviation (SD) WSS map of the controls was created. Regions of the individual WSS maps of the BAV patients that showed a higher WSS than the mean + 1.96SD of the ensemble-average control WSS map were highlighted. Elevated WSS was found on the greater ascending aorta (35% ± 15 of the surface area), which correlated significantly with peak systolic velocity (R (2) = 0.5, p = 0.01) and showed good agreement with the resected aortic regions. This novel approach to characterize regional aortic WSS may allow clinicians to gain unique insights regarding the heterogeneous expression of aortopathy and may be leveraged to guide patient-specific resection strategies for aorta repair.

Whole exome sequencing for familial bicuspid aortic valve identifies putative variants

BACKGROUND

Bicuspid aortic valve (BAV) is the most common congenital cardiovascular malformation. Although highly heritable, few causal variants have been identified. The purpose of this study was to identify genetic variants underlying BAV by whole exome sequencing a multiplex BAV kindred.

METHODS AND RESULTS

Whole exome sequencing was performed on 17 individuals from a single family (BAV=3; other cardiovascular malformation, 3). Postvariant calling error control metrics were established after examining the relationship between Mendelian inheritance error rate and coverage, quality score, and call rate. To determine the most effective approach to identifying susceptibility variants from among 54 674 variants passing error control metrics, we evaluated 3 variant selection strategies frequently used in whole exome sequencing studies plus extended family linkage. No putative rare, high-effect variants were identified in all affected but no unaffected individuals. Eight high-effect variants were identified by ≥2 of the commonly used selection strategies; however, these were either common in the general population (>10%) or present in the majority of the unaffected family members. However, using extended family linkage, 3 synonymous variants were identified; all 3 variants were identified by at least one other strategy.

CONCLUSIONS

These results suggest that traditional whole exome sequencing approaches, which assume causal variants alter coding sense, may be insufficient for BAV and other complex traits. Identification of disease-associated variants is facilitated by the use of segregation within families.

Rare GATA5 sequence variants identified in individuals with bicuspid aortic valve

BACKGROUND

Bicuspid aortic valve (BAV) is the most common type of congenital heart disease (CHD) and has a proposed genetic etiology. BAV is categorized by cusp fusion, with right-left (R-L) cusp fusion being associated with additional CHD, and right-noncoronary cusp (R-NC) fusion being associated with aortic valve dysfunction. Loss of murine Gata5, which encodes a cardiac transcription factor, results in a partially penetrant R-NC BAV, and we hypothesize that mutations in GATA5 are associated with R-NC BAV in humans.

METHODS

A cohort of 78 BAV patients (50 with isolated BAV and 28 with associated aortic coarctation) was analyzed using Sanger sequencing to identify GATA5 sequence variants. Biochemical assays were performed to identify functional deficits of identified sequence variants.

RESULTS

We identified two rare heterozygous nonsynonymous variants, p.Gln3Arg and p.Leu233Pro, for a frequency of 2.6% (2/78). Both individuals with nonsynonymous variants had BAV and aortic coarctation, one R-L and one R-NC subtype. Of the nonsynonymous variants, only p.Gln3Arg demonstrated decreased transcriptional activity in vitro.

CONCLUSION

Rare sequence variants in GATA5 are associated with human BAV. Our findings suggest a genotype-phenotype correlation in regards to associated CHD but not cusp fusion.

Cardiovascular genomics: implications for acute and critical care nurses

As genomic health care becomes commonplace, nurses will be asked to provide genomic care in all health care settings including acute care and critical care. Three common cardiac conditions are reviewed, Marfan syndrome, bicuspid aortic valve, and hypertrophic cardiomyopathy, to provide acute care and critical care nurses with an overview of these pathologies through the lens of genomics and relevant case studies. This information will help critical care nursing leaders become familiar with genetics related to common cardiac conditions and prepare acute care and critical care nurses for a new phase in patient diagnostics, with greater emphasis on early diagnosis and recognition of conditions before sudden cardiac death.

A unique aortic arterial meshwork with a major aortopulmonary collateral artery, a major arteriovenous collateral artery, and a coronary arteriovenous fistula in a young man with a bicuspid aortic valve

This report describes a case of an asymptomatic 18-year-old boy with a grade 1/6 ejection systolic murmur in the aortic area referred for an echocardiographic study to rule out a congenital heart disease. The patient had situs solitus, levocardia, bicuspid aortic valve, dilation of the proximal portions of the right coronary artery, and arteriovenous coronary fistula of the anomalous coronary branch originating from the anterior descending coronary artery into the main pulmonary artery. In addition he had a unique aortic arterial meshwork constituted by arteries originating from the inferior and posterior aspect of the distal portion of the transverse aortic arch, intersegmentary arteries originating from the lateral and anterior aspect of the proximal portion of the descending aorta, and the true bronchial artery with a major arteriovenous collateral artery draining into the superior vena cava and the superior division of the left lower pulmonary vein as well as a major aortopulmonary collateral artery anastomosed with a bronchial artery and draining into the posterior aspect of the right pulmonary artery. The use of transthoracic two-dimensional color flow Doppler echocardiography, magnetic resonance angiography and multislice computed tomography to establish a detailed morphologic analysis and the presence of associated anomalies in patients with a bicuspid aortic valve are discussed.

The role of transesophageal echocardiography in aortic valve preserving procedures

In selected cases of aortic regurgitation, aortic valve (AV) repair and AV sparing root reconstruction viable alternatives to aortic valve replacement. Repair and preservation of the native valve avoids the use of long-term anticoagulation, lowers the incidence of subsequent thromboembolic events and reduces the risk of endocarditis. Additionally repair has a low operative mortality with reasonable mid-term durability. The success and longer term durability of AVPP has improved with surgical experience. An understanding of the mechanism of the AR is integral to determining feasibility and success of an AVPP. Assessment of AV morphology, anatomy of the functional aortic annulus (FAA) and the aortic root with transesophageal echocardiography (TEE) improves the understanding of the mechanisms of AR. Pre- and intra-operative TEE plays a pivotal role in guiding case selection, surgical planning, and in evaluating procedural success. Post-operative transthoracic echocardiography is useful to determine long-term success and monitor for recurrence of AR.

Valve cuspidity: a risk factor for aortic valve repair?

BACKGROUND

The aim of this study was to analyze short- and mid-term results after aortic valve (AV) repair with particular regard to the impact of valve cuspidity (bicuspid versus tricuspid aortic valve).

METHODS

One hundred patients with aortic regurgitation (AR) undergoing aortic valve repair between November 2007 and October 2012 were included in the study. Sixty patients had bicuspid AV (BAV group; 11 females) and 40 patients had tricuspid AV (TAV group; 13 females). AR > grade 2 was present in 47 (78%) patients in the BAV and in 35 (88%) patients in the TAV group. Follow-up was complete in 100% and median was 25 months.

RESULTS

Isolated aortic valve repair was performed in 27 (45%) of BAV patients and in six (15%) of TAV patients. Replacement of the ascending aorta and/or aortic root was performed in 33 (55%) of BAV patients and in 34 (86%) of TAV patients. There was no death within 30 days postoperatively, while two patients died (TAV group) during the follow-up period. There was no statistical difference between BAV and TAV groups with regard to the survival (100 ± 0% vs. 95 ± 4%, p = 0.102), the three-year freedom from AV-related reoperation (90 ± 5% vs. 89 ± 6%, p = 0.456), and the three-year freedom from AR grade > 2 (86 ± 6% vs. 82 ± 7%, p = 0.866), respectively.

CONCLUSIONS

This study demonstrates no difference in mid-term results after regurgitant bicuspid and tricuspid aortic valve repair, suggesting that bicuspid valve may not be a risk factor for aortic valve repair.

Aortic valve type and calcification as assessed by transthoracic and transoesophageal echocardiography

INTRODUCTION

Aortic valve calcification (AVC) may predict poor outcome. Bicuspid aortic valve (BAV) leads to several haemodynamic changes accelerating the progress of aortic valve (AV) disease.

AIMS

To compare the diagnostic accuracy of transoesophageal echocardiography (TEE) and transthoracic echocardiography (TTE) in the assessment of aortic valve phenotype and degree of AVC, with intra-operative evaluation as a reference.

METHODS

We examined 169 patients (median age 65 years, 51 women) without significant coronary artery disease undergoing AV and/or aortic root surgery. TTE was performed within a week prior to surgery and TEE at the time of surgery.

RESULTS

Compared with surgical AVC assessment, visual evaluation using a 5-grade scoring system and real-time images showed a higher correlation (TTE r = 0·83 and TEE r = 0·82) than visual (TTE r = 0·64 and TEE 0·63) or grey scale mean (GSMn) (TTE r = 0·63 and TEE r = 0·52) assessment of end-diastolic still frames. AVC assessment using real-time images showed high intraclass correlation coefficients (TTE 0·94 and TEE 0·93). With regard to BAV, TEE was superior to TTE with a higher interobserver agreement, sensitivity and specificity (0·86, 92% and 94% versus 0·57, 77% and 82%, respectively).

CONCLUSION

Semi-quantitative AVC assessment of real-time cine loops from both TEE and TTE correlated well with intra-operative evaluation of AVC. Applying a predefined scoring system for AVC evaluation assures a high interobserver correlation. TEE was superior to TTE for evaluation of valve phenotype and should be considered when a diagnosis of BAV is clinically important.

Aortic distensibility in bicuspid aortic valve patients with normal aortic diameter

Objective:

Bicuspid aortic valve (BAV) is associated with aortic abnormalities. The ascending aorta tends to dilate and its elasticity deteriorates. The morphology of the BAV and the elasticity of the proximal ascending aorta seem to influence the outcome. This study aimed to determine the distensibility of the ascending aorta with normal diameter in BAV patients and its relation to its morphology.

Methods:

This is a cross-sectional study. In the patients with BAV referred for echocardiography, the phenotype was defined as anteroposterior (AP) or mediolateral (ML) leaflet orientations. The aortic distensibility at 5–10 mm above the sinotubular junction was assessed using transthoracic echocardiography in 50 BAV patients, and 50 healthy controls with tricuspid aortic valve (TAV) matched by gender and age.

Results:

The ascending aorta in BAV patients had less distensibility compared with that in the control subjects (0.00298 ± 0.0023 versus 0.00805 ± 0.0028 cm2 dynes−1 × 10−6, respectively, p < 0.001). The ML phenotype of BAVs was more frequent. However, the reduced distensibility was not related to gender and morphology of the valve.

Conclusions:

Regardless of the valve morphology and also in the absence of aortic dilation, aortic distensibility is impaired in BAV subjects compared with TAV subjects. This finding supports the idea of an intrinsic aortic wall anomalies underlying the impaired elasticity of the aorta in BAV patients.

The long non-coding HOTAIR is modulated by cyclic stretch and WNT/β-CATENIN in human aortic valve cells and is a novel repressor of calcification genes

Aortic valve calcification is a significant and serious clinical problem for which there are no effective medical treatments. Individuals born with bicuspid aortic valves, 1–2% of the population, are at the highest risk of developing aortic valve calcification. Aortic valve calcification involves increased expression of calcification and inflammatory genes. Bicuspid aortic valve leaflets experience increased biomechanical strain as compared to normal tricuspid aortic valves. The molecular pathogenesis involved in the calcification of BAVs are not well understood, especially the molecular response to mechanical stretch. HOTAIR is a long non-coding RNA (lncRNA) that has been implicated with cancer but has not been studied in cardiac disease. We have found that HOTAIR levels are decreased in BAVs and in human aortic interstitial cells (AVICs) exposed to cyclic stretch. Reducing HOTAIR levels via siRNA in AVICs results in increased expression of calcification genes. Our data suggest that β-CATENIN is a stretch responsive signaling pathway that represses HOTAIR. This is the first report demonstrating that HOTAIR is mechanoresponsive and repressed by WNT β-CATENIN signaling. These findings provide novel evidence that HOTAIR is involved in aortic valve calcification.

Preservation of the bicuspid aortic valve associated with aneurysms of the aortic root and ascending aorta

INTRODUCTION AND OBJECTIVES

When the bicuspid aortic valve is associated with dilatation of the aorta, surgical repair requires correction of all the components of the aortic root. Here, we review our experience in this type of surgery.

METHODS

A descriptive and retrospective observational study was carried out to analyze morbidity and mortality in valve-sparing techniques and evaluate the medium-term durability of the aortic valve. We included all patients with a bicuspid aortic valve and dilatation of the aorta who underwent surgery with a valve-sparing technique in our center between 1999 and 2011.

RESULTS

A total of 151 patients underwent surgery. A valve-sparing technique was used in 51 patients. The mean (standard deviation) age of the patients was 51 (12) years and 92% were men. In 69% of the patients, aortic insufficiency was less than grade II and the aortic cusps showed little structural degeneration. Valve reimplantation was performed in 32 patients. There was no hospital mortality. With a median follow-up of 36 months (interquartile range, 18-45 months), none of the patients died or required reoperation, and all patients were free of aortic insufficiency greater than grade II.

CONCLUSIONS

Valve-preserving surgery in bicuspid aortic valves associated with dilatation of the aorta shows excellent short- and medium-term results in selected valves. The stabilization of all of the components of the aortic root improves the durability of the valve, and the techniques proposed are reproducible and stable in the medium-term.

Toward individualized management of the ascending aorta in bicuspid aortic valve surgery: the role of valve phenotype in 1362 patients

OBJECTIVE

Decision making regarding the management of the ascending aorta (AA) in patients with a bicuspid aortic valve (BAV) undergoing valve surgery has hardly been individualized and remains controversial. We analyzed our individualized, multifactorial approach, focusing on the BAV phenotype.

METHODS

In 1362 patients (1044 men) undergoing aortic valve surgery, the BAV phenotypes were intraoperatively classified and retrospectively analyzed. The mean follow-up was 5.4±3.6 years (range, 0-14; 7334 patient-years), and the data were 96.5% complete. The individualized AA management decision process mainly included the AA diameter, age, body surface area, macroscopic AA configuration, and the perceived tissue strength of the aortic wall resulting in 3 AA treatment groups: no intervention, aortoplasty (AoP), and AA replacement (AAR).

RESULTS

In 906 patients (66.5%), no intervention was performed and 172 (12.6%) and 284 (20.9%) underwent AoP and AAR, respectively. The hospital mortality was 1.1% for no intervention, 0.6% for AoP, and 0.4% for AAR (P=.4). The 10-year survival was similar for all 3 groups and comparable to that of the general population. Five reoperations on the AA occurred, 4 in the no intervention and 1 in the AoP group. BAV type 2/unicuspid patients were younger and more had undergone AAR in absolute numbers and after allowing for the AA diameter. Also, in patients with BAV type 1 LR and regurgitation, AAR was performed more often.

CONCLUSIONS

The individualized, multifactorial management of AA in patients with BAV during aortic valve surgery leads to excellent results. The threshold AA diameter for intervention (AoP or AAR) varied from 34 to 51 mm (mean, 43.9). BAV type 2/unicuspid and BAV type 1 LR with regurgitation emerged as determinants for more liberal AAR in our practice. Longer term follow-up is necessary to confirm our conclusions.

Spectrum of Echocardiographic Abnormalities among 168 Consecutive Referrals to an Urban Private Hospital in South-Western Nigeria

Trans-thoracic echocardiography (TTE) is an important non-invasive cardiac examination that provides structural and functional information. It is useful in the diagnosis of cardiac diseases and often guides the management and follow-up of patients with cardiovascular diseases (CVD). The study aimed to present an audit of the echocardiograms performed in an urban private hospital over a two-year period in order to define the pattern of cardiac diseases in our center. Echocardiogram reports of 168 consecutive patients performed between May 2011 and April 2013 at an organized private sector hospital in Lagos, south-west Nigeria were reviewed. Studies were performed with a Toshiba Nemio XG ultrasound machine. The data obtained were analyzed for mean age, sex, clinical indications, and echocardiographic diagnosis in the study subjects. A total of 168 echocardiography reports were examined, comprising of 92 males (54.8%) and 76 females (45.2%). The age range of the subjects was 10-76 years (mean 42.5 ± 12.1 years). The commonest indication for echocardiography was systemic hypertension and hypertension related causes (38.1%), followed by abnormal resting electrocardiogram (14.9%). Routine annual medical screening was the next most common indication, representing 13.1% of the indications for echocardiography. The other indications are as presented in Table 1. The echocardiogram was normal in 64.3% of the subjects. The commonest abnormality detected was hypertensive heart disease (HHD); accounting for 9.6% of the subjects studied. Isolated atrial enlargement (left, right, or bi-atrial) was the next most common abnormality accounting for 6% of the echocardiographic diagnosis. Pulmonary hypertension was the next most common diagnosis accounting for 4.8% of our findings. The other echocardiographic diagnoses are as listed in Table 2. Hypertension represents the commonest indication for echocardiography. Normal echocardiogram was the commonest echocardiographic finding while HHD was the commonest echocardiographic abnormality. The prevalence of ischemic heart disease by echocardiography was 2.4%. There was no case of rheumatic heart disease (RHD). The prevalence of hypertrophic cardiomyopathy (HCM) was 1.2%. Ease of access to echocardiography may influence the findings in an echocardiographic audit and policy makers should incorporate appropriateness criteria into their guidelines for reimbursement.

GATA5 loss-of-function mutations associated with congenital bicuspid aortic valve

Bicuspid aortic valve (BAV) is the most common form of congenital cardiovascular defect in humans worldwide and is responsible for substantial morbidity and mortality. Accumulating evidence has demonstated that genetic risk factors are involved in the pathogenesis of BAV. However, BAV is genetically heterogeneous and the genetic basis underlying BAV in a large number of patients remains unknown. In the present study, the coding regions and splice junction sites of the GATA5 gene, which codes for a zinc-finger transcription factor crucial for the normal development of the aortic valve, was sequenced initially in 110 unrelated patients with BAV. The available relatives of the mutation carriers and 200 unrelated healthy individuals used as controls were subsequently genotyped for GATA5. The functional effect of the mutations was characterized by using a luciferase reporter assay system. As a result, two novel heterozygous GATA5 mutations, p.Y16D and p.T252P, were identified in two families with autosomal dominant inheritance of BAV, respectively. The variations were absent in 400 control chromosomes and the altered amino acids were completely conserved evolutionarily. Functional assays revealed that the two GATA5 mutants were associated with significantly reduced transcriptional activity compared with their wild-type counterpart. To the best of our knowledge, this is the first study on the association of GATA5 loss-of-function mutations with enhanced susceptibility to BAV, providing novel insight into the molecular mechanism involved in human BAV and suggesting a potential role for the early prophylaxis and personalized treatment of this common congenital heart disease.

Aortic root disease in athletes: aortic root dilation, anomalous coronary artery, bicuspid aortic valve, and Marfan's syndrome

Two professional athletes in the U.S. National Basketball Association required surgery for aortic root dilation in 2012. These cases have attracted attention in sports medicine to the importance of aortic root disease in athletes. In addition to aortic root dilation, other forms of aortic disease include anomalous coronary artery, bicuspid aortic valve, and Marfan's syndrome. In this review, electronic database literature searches were performed using the terms "aortic root" and "athletes." The literature search produced 122 manuscripts. Of these, 22 were on aortic root dilation, 21 on anomalous coronary arteries, 12 on bicuspid aortic valves, and 8 on Marfan's syndrome. Aortic root dilation is a condition involving pathologic dilation of the aortic root, which can lead to life-threatening sequelae. Prevalence of the condition among athletes and higher risk athletes in particular sports needs to be better delineated. Normative parameters for aortic root diameter in the general population are proportionate to anthropomorphic variables, but this has not been validated for athletes at the extremes of anthropomorphic indices. Although echocardiography is the favored screening modality, computed tomography (CT) and cardiac magnetic resonance imaging (MRI) are also used for diagnosis and surgical planning. Medical management has utilized beta-blockers, with more recent use of angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), and statins. Indications for surgery are based on comorbidities, degree of dilation, and rate of progression. Management decisions for aortic root dilation in athletes are nuanced and will benefit from the development of evidence-based guidelines. Anomalous coronary artery is another form of aortic disease with relevance in athletes. Diagnosis has traditionally been through cardiac catheterization, but more recently has included evaluation with echocardiography, multislice CT, and MRI. Athletes with this condition should be restricted from participation in competitive sports, but can be cleared for participation 6 months after surgical repair. Bicuspid aortic valve is another form of aortic root disease with significance in athletes. Although echocardiography has traditionally been used for diagnosis, CT and MRI have proven more sensitive and specific. Management of bicuspid aortic valve consists of surveillance through echocardiography, medical therapy with beta-blockers and ARBs, and surgery. Guidelines for sports participation are based on the presence of aortic stenosis, aortic regurgitation, and aortic root dilation. Marfan's syndrome is a genetic disorder with a number of cardiac manifestations including aortic root dilation, aneurysm, and dissection. Medical management involves beta-blockers and ARBs. Thresholds for surgical management differ from the general population. With regard to sports participation, the most important consideration is early detection. Athletes with the stigmata of Marfan's syndrome or with family history should be tested. Further research should determine whether more aggressive screening is warranted in sports with taller athletes. Athletes with Marfan's syndrome should be restricted from activities involving collision and heavy contact, avoid isometric exercise, and only participate in activities with low intensity, low dynamic, and low static components. In summary, many forms of aortic root disease afflict athletes and need to be appreciated by sports medicine practitioners because of their potential to lead to tragic but preventable deaths in an otherwise healthy population.

Type F Congenital Quadricuspid Aortic Valve: A Very Rare Case Diagnosed by 3-dimenional Transoesophageal Echocardiography

Congenital quadricuspid aortic valve (QAV) is a rare cardiac anomaly. Several different anatomical variations of a quadricuspid aortic valve have been described. Aortic regurgitation is the predominant valvular dysfunction associated with QAV and patients tend to present in their 5^th or 6^th decade of life. This anomaly is rarely picked up by transthoracic echocardiogram (TTE). A comprehensive transoesophageal echocardiography (TOE) study is more likely to diagnose it. We describe a very rare type of QAV – Type F in a 52-year-old lady who presented with symptoms of shortness of breath and pre-syncope. We include TOE images and intra-operative valve images.

Bicuspid aortic valve hemodynamics induces abnormal medial remodeling in the convexity of porcine ascending aortas

The type-I bicuspid aortic valve (BAV), which differs from the normal tricuspid aortic valve (TAV) most commonly by left-right coronary cusp fusion, is frequently associated with secondary aortopathies. While BAV aortic dilation has been linked to a genetic predisposition, hemodynamics has emerged as a potential alternate etiology. However, the link between BAV hemodynamics and aortic medial degeneration has not been established. The objective of this study was to compare the regional wall shear stresses (WSS) in a TAV and BAV ascending aorta (AA) and to isolate ex vivo their respective impact on aortic wall remodeling. The WSS environments generated in the convex region of a TAV and BAV AA were predicted through fluid-structure interaction (FSI) simulations in an aorta model subjected to both valvular flows. Remodeling of porcine aortic tissue exposed to TAV and BAV AA WSS for 48 h in a cone-and-plate bioreactor was investigated via immunostaining, immunoblotting and zymography. FSI simulations revealed the existence of larger and more unidirectional WSS in the BAV than in the TAV AA convexity. Exposure of normal aortic tissue to BAV AA WSS resulted in increased MMP-2 and MMP-9 expressions and MMP-2 activity but similar fibrillin-1 content and microfibril organization relative to the TAV AA WSS treatment. This study confirms the sensitivity of aortic tissue to WSS abnormalities and demonstrates the susceptibility of BAV hemodynamic stresses to focally mediate aortic medial degradation. The results provide compelling support to the important role of hemodynamics in BAV secondary aortopathy.

Mechanism of aortic medial matrix remodeling is distinct in patients with bicuspid aortic valve

OBJECTIVES

Patients with bicuspid aortic valves (BAV) are predisposed to developing ascending thoracic aortic aneurysms (TAA) at an earlier age than patients who develop degenerative TAAs and have a tricuspid aortic valve (TAV). The hypothesis tested is that BAV-associated aortopathy is mediated by a mechanism of matrix remodeling that is distinct from that seen in TAAs of patients with tricuspid aortic valves.

METHODS

Aortic specimens were collected during ascending aortic replacement, aortic valve replacement, and heart transplants from nonaneurysmal (NA) donors and recipients. Matrix architecture of the aortic media was assessed qualitatively using multiphoton microscopy followed by quantification of collagen and elastin fiber orientation. α-Elastin was determined and matrix maturity was assessed by quantifying immature and mature collagen and lysyl oxidase (Lox) expression and activity in aortic specimens. Matrix metalloproteinase-2/9 activity was quantified in aortic smooth muscle cells.

RESULTS

Elastin and collagen fibers were more highly aligned in BAV-NA and BAV-TAA cases than in TAV-TAA cases, whereas TAV-TAA cases were more disorganized than TAV-NA cases. α-Elastin content was unchanged. Immature collagen was reduced in BAV-NA and BAV-TAA cases when compared with TAV-NA and TAV-TAA cases. Mature collagen was elevated in TAV-TAA cases compared with TAV-NA and BAV-TAA cases. There was a trend toward elevated Lox gene expression and activity and matrix metalloproteinase-2/9 activity for TAV-TAA, BAV-NA, and BAV-TAA specimens.

CONCLUSIONS

The highly aligned matrix architecture in patients with BAVs indicates that wall remodeling is distinct from TAV-TAA. Altered matrix architecture and reduced collagen maturity suggest that the effector molecules mediating the remodeling of TAAs are different in BAV and TAV cases.

The aortic valve: structure, complications and implications for transcatheter aortic valve replacement

The aortic valve operates in a complex haemodynamic environment, opening and closing over 100,000 times a day. When complications arise, such as aortic stenosis, prognosis can be very poor, leading to death within the first few years. Surgical valve replacement is currently the standard treatment for aortic stenosis. A thorough understanding of the anatomy and function of the native valve is imperative when developing a prosthetic replacement that can withstand the complex demands of the heart. This review focuses on the anatomy, structure and disease of the aortic valve and the implications for a transcatheter aortic valve replacement (TAVR). Current complications with TAVR, such as major vascular bleeding, conduction disturbances and patient-prosthesis mismatch (PPM), can be overcome by reducing the delivery profile and through the use of more accurate imaging technologies to work towards a fully functional and durable prosthesis.

M1/M2 macrophages and associated mechanisms in congenital bicuspid aortic valve stenosis

The aim of this study was to observe macrophage infiltration in congenital bicuspid aortic valve (CBAV) stenosis. M1/M2 macrophage distribution, inflammatory cytokine expression and the role of M1 macrophages during CBAV stenosis were also explored. The experimental and control groups comprised 30 severely stenotic CBAVs and 30 severely stenotic tricuspid aortic valves (TAVs), respectively. Histological and morphological changes were assessed using hematoxylin-eosin (HE) staining and mRNA levels of vascular endothelial growth factor (VEGF) were examined using the quantitative polymerase chain reaction. Nonspecific, M1 and M2 macrophages were monitored using cluster of differentiation (CD)68, inducible nitric oxide synthase (iNOS) and CD163 staining, respectively. Endothelial nitric oxide synthase (eNOS), interleukin (IL)-10, arginase (Arg)-1 and macrophage colony-stimulating factor (M-CSF) were also examined using immunohistochemical staining. Of note, HE staining revealed a higher cell density and neovascularization was more common in CBAVs than TAVs. At the mRNA level, VEGF expression was two-fold higher in CBAVs relative to that in TAVs (P=0.02). Furthermore, CD68 and iNOS were significantly higher in CBAVs compared with TAVs (P=0.029 and 0.021, respectively), while CD163 expression was lower in CBAVs (P=0.033). In addition, eNOS expression was higher and Arg-1, IL-10 and M-CSF expression were lower in CBAVs compared with TAVs (all P<0.0001). The present study suggested that CBAVs are associated with a higher total and M1 macrophage density and a lower M2 macrophage density than TAVs, and that M1 macrophage infiltration may contribute to calcification of CBAVs.

Early screening for cardiovascular abnormalities with preparticipation echocardiography: utility of focused physician-operated echocardiography in preparticipation screening of athletes

OBJECTIVES

We have developed the Early Screening for Cardiovascular Abnormalities With Preparticipation Echocardiography protocol to improve false-positive rates, reduce referrals, and broaden the spectrum of disease that can be captured through preparticipation screening of athletes. This study documents the first application of this protocol and uses case analysis to discuss the potential utility of portable sonography in screening.

METHODS

Sixty-five male collegiate athletes, aged 18 to 25 years, were prospectively enrolled. Each athlete was screened with a history and physical examination, electrocardiography (ECG), and focused echocardiography performed by a noncardiologist sports medicine physician. The history and physical examination were based on the 12-element American Heart Association recommendations; 2010 European Society of Cardiology criteria were used to screen ECGs. Focused physician-operated echocardiography was performed to assess for hypertrophic cardiomyopathy and aortic root dilatation. Athletes screening positive were referred to a cardiologist.

RESULTS

Most of the athletes (n = 59) did not screen positive by any screening modality. Three athletes screened positive on ECG but had normal focused echocardiographic findings. Three athletes screened positive by history and physical examination but had normal ECG and focused echocardiographic findings. All athletes screening positive were referred to a cardiologist and eventually cleared for sports participation. No athlete screened positive by focused echocardiography alone. Focused echocardiography was able to reduce the referral rate for hypertrophic cardiomyopathy by 33% and obtained measurements statistically similar to those of formal echocardiography.

CONCLUSIONS

This study provides evidence that focused physician-operated echocardiography can improve false-positive rates and broaden the spectrum of disease that is detectable through preparticipation screening of athletes.

Teenage heart murmurs

The first-time appearance of a murmur in an adolescent can create a substantial amount of anxiety in the parents and the teenager. The appropriate evaluation and diagnosis is very important in decision-making regarding sports participation in this population. Accurate identification of the innocent murmurs can obviate the need for echocardiography. Identification of a pathologic murmur may reduce morbidity and, possibly, mortality in critical lesions such as hypertrophic cardiomyopathy. This article discusses the physiology and characteristics of different murmurs, and outlines an approach to cardiac murmurs in adolescents.

Bicuspid aortic valve disease: recent insights in pathophysiology and treatment

Bicuspid aortic valve is a common congenital cardiac malformation with a broad spectrum of clinical outcomes. Bicuspid aortic valve may go undetected throughout an individual's lifetime or, alternatively, they may have devastating clinical consequences, resulting in death. Both clinicians and medical scientists have taken a renewed interest in the development, pathophysiology and treatment options for this subtle but often substantial clinical entity. Evidence is mounting to suggest that an underlying disease of the aorta is inherited with bicuspid aortic valve, although considerable controversy surrounds this theory. Novel molecular mechanisms underlying the valve and vascular pathologies, as well as new surgical therapies for these patients have been proposed in the past 10 years.