Abnormal extracellular matrix protein transport associated with increased apoptosis of vascular smooth muscle cells in Marfan syndrome and bicuspid aortic valve thoracic aortic aneurysm

Background - Marfan syndrome (MS) is a genetic disorder caused by a mutation in the fibrillin gene FBN1. Bicuspid aortic valve (BAV) is a congenital heart malformation of unknown cause. Both conditions are associated with ascending aortic aneurysm and premature death. This study examined the relationship among the secretion of extracellular matrix proteins fibrillin, fibronectin, tenascin, and vascular smooth muscle cell (VSMC) apoptosis. The role of matrix metalloproteinase (MMP)- 2 in VSMC apoptosis was studied in MS aneurysm. Methods and Results - Aneurysm tissue was obtained from patients undergoing surgery ( MS: 4 M, 1 F, age 27 - 45 years; BAV: 3 M, 2 F, age 28 - 65 years). Normal aorta from subjects with nonaneurysm disease was also collected ( 4 M, 1 F, age 23 - 93 years). MS and BAV aneurysm histology showed areas of cystic medial necrosis (CMN) without inflammatory infiltrate. Immunohistochemical study of cultured MS and BAV VSMC showed intracellular accumulation and reduction of extracellular distribution of fibrillin, fibronectin, and tenascin. Western blot showed no increase in expression of fibrillin, fibronectin, or tenascin in MS or BAV VSMC and increased expression of MMP-2 in MS VSMCs. There was 4-fold increase in loss of cultured VSMC incubated in serum-free medium for 24 hours in both MS ( 27 +/- 8%) and BAV ( 32 +/- 14%) compared with control ( 7 +/- 5%). Conclusions - In MS and BAV there is alteration in both the amount and quality of secreted proteins and an increased degree of VSMC apoptosis. Up-regulation of MMP-2 might play a role in VSMC apoptosis in MS VSMC. The findings suggest the presence of a fundamental cellular abnormality in BAV thoracic aorta, possibly of genetic origin.

Quantification of aortic flow by phase-contrast magnetic resonance in patients with bicuspid aortic valve.

AIMS: Bicuspid aortic valve (BAV) causes complex flow patterns in the ascending aorta (AAo), which may compromise the accuracy of flow measurement by phase-contrast magnetic resonance (PC-MR). Therefore, we aimed to assess and compare the accuracy of forward flow measurement in the AAo, where complex flow is more dominant in BAV patients, with flow quantification in the left ventricular outflow tract (LVOT) and the aortic valve orifice (AV), where complex flow is less important, in BAV patients and controls. METHODS AND RESULTS: Flow was measured by PC-MR in 22 BAV patients and 20 controls at the following positions: (i) LVOT, (ii) AV, and (iii) AAo, and compared with the left ventricular stroke volume (LVSV). The correlation between the LVSV and the forward flow in the LVOT, the AV, and the AAo was good in BAV patients (r = 0.97/0.96/0.93; P < 0.01) and controls (r = 0.96/0.93/0.93; P < 0.01). However, in relation with the LVSV, the forward flow in the AAo was mildly underestimated in controls and much more in BAV patients [median (inter-quartile range): 9% (4%/15%) vs. 22% (8%/30%); P < 0.01]. This was not the case in the LVOT and the AV. The severity of flow underestimation in the AAo was associated with flow eccentricity. CONCLUSION: Flow measurement in the AAo leads to an underestimation of the forward flow in BAV patients. Measurement in the LVOT or the AV, where complex flow is less prominent, is an alternative means for quantifying the systolic forward flow in BAV patients.

Successful Transapical Aortic Valve Implantation in a Congenital Bicuspid Aortic Valve.

Transcatheter stent-valve implantation in stenosed congenital bicuspid aortic valves is under debate. Heavily calcified elliptic bicuspid valves represent a contraindication to catheter-based valve therapies because of a risk of stent-valve displacement, distortion, or malfunctioning after the implantation. In this case report we illustrate our experience with a patient suffering from stenosed congenital bicuspid aortic valve who successfully underwent a transapical 26-mm Edwards Sapien stent-valve (Edwards Lifesciences Inc, Irvine, CA) implantation. Postoperative distortion, malfunctioning, and paravalvular leaks were not detected.

Aortic valve dysfunction and aortic dilation in adults with coarctation of the aorta.

OBJECTIVES: To determine the prevalence of aortic valve dysfunction, aortic dilation, and aortic valve and ascending aortic intervention in adults with coarctation of the aorta (CoA). BACKGROUND: Aortic valve dysfunction and aortic dilation are rare among children and adolescents with CoA. With longer follow-up, adults may be more likely to have progressive disease. METHODS: We retrospectively reviewed all adults with CoA, repaired or unrepaired, seen at our center between 2004 and 2010. RESULTS: Two hundred sixteen adults (56.0% male) with CoA were identified. Median age at last evaluation was 28.3 (range 18.0 to 75.3) years. Bicuspid aortic valve (BAV) was present in 65.7%. At last follow-up, 3.2% had moderate or severe aortic stenosis, and 3.7% had moderate or severe aortic regurgitation. Dilation of the aortic root or ascending aorta was present in 28.0% and 41.6% of patients, respectively. Moderate or severe aortic root or ascending aortic dilation (z-score > 4) was present in 8.2% and 13.7%, respectively. Patients with BAV were more likely to have moderate or severe ascending aortic dilation compared with those without BAV (19.5% vs. 0%; P < 0.001). Age was associated with ascending aortic dilation (P = 0.04). At most recent follow-up, 5.6% had undergone aortic valve intervention, and 3.2% had aortic root or ascending aortic replacement. CONCLUSION: In adults with CoA, significant aortic valve dysfunction and interventions during early adulthood were uncommon. However, aortic dilation was prevalent, especially of the ascending aorta, in patients with BAV.

Pilot licensing after aortic valve surgery.

Background and aim of the study: Bicuspid aortic valve is the most common congenital heart malformation, and a high percentage of patients with this condition will develop complications over time. It is rare that pilots undergo aortic valve surgery, and the confirmation of flight-licensing requirements after aortic valve replacement (AVR) is a challenge for the patient's cardiac surgeon and, particularly, for the Aeromedical Examiner (AME). Only AMEs are able to determine the flight status of pilots. Furthermore, in military and in civil aviation (e.g., Red Bull Air Race), the high G-load environment experienced by pilots is an exceptional physiological parameter, which must be considered postoperatively. Methods: A review was conducted of the aeronautical, surgical and medical literature, and of European pilot-licensing regulations. Case studies are also reported for two Swiss Air Force pilots. Results: According to European legislation, pilots can return to flight duty from the sixth postoperative month, with the following limitations: that an aortic bioprosthesis presents no restrictions in cardiac function, requires no cardioactive medications, yet requires a flight operation with co-pilot, the avoidance of accelerations over +3 Gz and, in military aviation, restricts the pilot to non-ejection-seat aircraft. The patient follow up must include both echocardiographic and rhythm assessments every six months. Mechanical prostheses cannot be certified because the required anticoagulation therapy is a disqualifying condition for pilot licensing. Conclusion: Pilot licensing after aortic valve surgery is possible, but with restrictions. The +Gz exposition is of concern in both military and civilian aviation (aerobatics). The choice of bioprosthesis type and size is determinant. Pericardial and stentless valves seem to show better flow characteristics under high-output conditions. Repetitive cardiological controls are mandatory for the early assessment of structural valve disease and rhythm disturbances. A pre-emptive timing is recommended when reoperation is indicated, without waiting for clinical manifestations of structural valve disease.

Aortic Annulus Stabilization Technique for Rapid Deployment Aortic Valve Replacement.

NlmCategory="UNASSIGNED">Rapid deployment aortic valve replacement (RDAVR) with the use of rapid deployment valve systems represents a smart alternative to the use of standard aortic bioprosthesis for aortic valve replacement. Nevertheless, its use is still debatable in patients with pure aortic valve regurgitation or true bicuspid aortic valve because of the risk of postoperative paravalvular leak. To address this issue, an optimal annulus-valve size match seems to be the ideal surgical strategy. This article describes a new technique developed to stabilize the aortic annulus and prevent paravalvular leak after RDAVR. To confirm the feasibility, this technique was performed in six patients with severe symptomatic aortic stenosis who were scheduled to undergo aortic valve replacement at our center. All patients survived surgery and were discharged from the hospital. There were no new intracardiac conduction system disturbances observed, and a permanent pacemaker implantation was not required in any of the patients. The intraoperative and postoperative echocardiogram confirmed successful positioning of the valve, and no paravalvular leak was observed. In this preliminary experience, RDAVR through a full sternotomy or an upper hemisternotomy approach with the use of aortic annulus stabilization technique was safe, and no leak was observed. Future studies on large series of patients are necessary to confirm the safety and effectiveness of this technique in preventing paravalvular leak in patients with true bicuspid aortic valves or pure aortic regurgitation.

Mechanical strain induces the production of spheroid mineralized microparticles in the aortic valve through a RhoA/ROCK-dependent mechanism

Calcific aortic valve disease (CAVD) is a chronic disorder characterized by an abnormal mineralization of the leaflets, which is accelerated in bicuspid aortic valve (BAV). It is suspected that mechanical strain may promote/enhance mineralization of the aortic valve. However, the effect of mechanical strain and the involved pathways during mineralization of the aortic valve remains largely unknown. Valve interstitial cells (VICs) were isolated and studied under strain conditions. Human bicuspid aortic valves were examined as a model relevant to increase mechanical strain. Cyclic strain increased mineralization of VICs by several-fold. Scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analyses revealed that mechanical strain promoted the formation of mineralized spheroid microparticles, which coalesced into larger structure at the surface of apoptotic VICs. Apoptosis and mineralization were closely associated with expression of ENPP1. Inhibition of ENPP1 greatly reduced mineralization of VIC cultures. Through several lines of evidence we showed that mechanical strain promoted the export of ENPP1-containing vesicles to the plasma membrane through a RhoA/ROCK pathway. Studies conducted in human BAV revealed the presence of spheroid mineralized structures along with the expression of ENPP1 in areas of high mechanical strain. Mechanical strain promotes the production and accumulation of spheroid mineralized microparticles by VICs, which may represent one important underlying mechanism involved in aortic valve mineralization. RhoA/ROCK-mediated export of ENPP1 to the plasma membrane promotes strain-induced mineralization of VICs.

Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Disease.

BACKGROUND Limited information exists describing the results of transcatheter aortic valve (TAV) replacement in patients with bicuspid aortic valve (BAV) disease (TAV-in-BAV). OBJECTIVES This study sought to evaluate clinical outcomes of a large cohort of patients undergoing TAV-in-BAV. METHODS We retrospectively collected baseline characteristics, procedural data, and clinical follow-up findings from 12 centers in Europe and Canada that had performed TAV-in-BAV. RESULTS A total of 139 patients underwent TAV-in-BAV with the balloon-expandable transcatheter heart valve (THV) (n = 48) or self-expandable THV (n = 91) systems. Patient mean age and Society of Thoracic Surgeons predicted risk of mortality scores were 78.0 ± 8.9 years and 4.9 ± 3.4%, respectively. BAV stenosis occurred in 65.5%, regurgitation in 0.7%, and mixed disease in 33.8% of patients. Incidence of type 0 BAV was 26.7%; type 1 BAV was 68.3%; and type 2 BAV was 5.0%. Multislice computed tomography (MSCT)-based TAV sizing was used in 63.5% of patients (77.1% balloon-expandable THV vs. 56.0% self-expandable THV, p = 0.02). Procedural mortality was 3.6%, with TAV embolization in 2.2% and conversion to surgery in 2.2%. The mean aortic gradient decreased from 48.7 ± 16.5 mm Hg to 11.4 ± 9.9 mm Hg (p < 0.0001). Post-implantation aortic regurgitation (AR) grade ≥2 occurred in 28.4% (19.6% balloon-expandable THV vs. 32.2% self-expandable THV, p = 0.11) but was prevalent in only 17.4% when MSCT-based TAV sizing was performed (16.7% balloon-expandable THV vs. 17.6% self-expandable THV, p = 0.99). MSCT sizing was associated with reduced AR on multivariate analysis (odds ratio [OR]: 0.19, 95% confidence intervals [CI]: 0.08 to 0.45; p < 0.0001). Thirty-day device safety, success, and efficacy were noted in 79.1%, 89.9%, and 84.9% of patients, respectively. One-year mortality was 17.5%. Major vascular complications were associated with increased 1-year mortality (OR: 5.66, 95% CI: 1.21 to 26.43; p = 0.03). CONCLUSIONS TAV-in-BAV is feasible with encouraging short- and intermediate-term clinical outcomes. Importantly, a high incidence of post-implantation AR is observed, which appears to be mitigated by MSCT-based TAV sizing. Given the suboptimal echocardiographic results, further study is required to evaluate long-term efficacy.

Clinical and haemodynamic outcomes in 658 patients receiving the Perceval sutureless aortic valve: early results from a prospective European multicentre study (the Cavalier Trial)†.

OBJECTIVES The aim of the Cavalier trial was to evaluate the safety and performance of the Perceval sutureless aortic valve in patients undergoing aortic valve replacement (AVR). We report the 30-day clinical and haemodynamic outcomes from the largest study cohort with a sutureless valve. METHODS From February 2010 to September 2013, 658 consecutive patients (mean age 77.8 years; 64.4% females; mean logistic EuroSCORE 10.2%) underwent AVR in 25 European Centres. Isolated AVRs were performed in 451 (68.5%) patients with a less invasive approach in 219 (33.3%) cases. Of the total, 40.0% were octogenarians. Congenital bicuspid aortic valve was considered an exclusion criterion. RESULTS Implantation was successful in 628 patients (95.4%). In isolated AVR through sternotomy, the mean cross-clamp time and the cardiopulmonary bypass (CPB) time were 32.6 and 53.7 min, and with the less invasive approach 38.8 and 64.5 min, respectively. The 30-day overall and valve-related mortality rates were 3.7 and 0.5%, respectively. Valve explants, stroke and endocarditis occurred in 0.6, 2.1 and in 0.1% of cases, respectively. Preoperative mean and peak pressure gradients decreased from 44.8 and 73.24 mmHg to 10.24 and 19.27 mmHg at discharge, respectively. The mean effective orifice area improved from 0.72 to 1.46 cm(2). CONCLUSIONS The current 30-day results show that the Perceval valve is safe (favourable haemodynamic effect and low complication rate), and can be implanted with a fast and reproducible technique after a short learning period. Short cross-clamp and CPB times were achieved in both isolated and combined procedures. The Perceval valve represents a promising alternative to biological AVR, especially with a less invasive approach and in older patients.

Proteomic alterations in heat shock protein 27 and identification of phosphoproteins in ascending aortic aneurysm associated with bicuspid and tricuspid aortic valve

Whether or not there are molecular differences, at the intra- and extracellular level, between aortic dilatation in patients with bicuspid (BAV) and those with a tricuspid aortic valve (TAV) has remained controversial for years. We have performed 2-dimensional gel electrophoresis and mass spectrometry coupled with dephosphorylation and phosphostaining experiments to reveal and define protein alterations and the high abundant structural phosphoproteins in BAV compared to TAV aortic aneurysm samples. 2-D gel patterns showed a high correlation in protein expression between BAV and TAV specimens (n=10). Few proteins showed significant differences, among those a phosphorylated form of heat shock protein (HSP) 27 with significantly lower expression in BAV compared to TAV aortic samples (p=0.02). The phosphoprotein tracing revealed four different phosphoproteins including Rho GDP dissociation inhibitor 1, calponin 3, myosin regulatory light chain 2 and four differentially phosphorylated forms of HSP27. Levels of total HSP27 and dually phosphorylated HSP27 (S78/S82) were investigated in an extended patient cohort (n=15) using ELISA. Total HSP27 was significantly lower in BAV compared to TAV patients (p=0.03), with no correlation in levels of phospho-HSP27 (S78/S82) (p=0.4). Western blots analysis showed a trend towards lower levels of phospho-HSP27 (S78) in BAV patients (p=0.07). Immunohistochemical analysis revealed that differences in HSP27 occur in the cytoplasma of VSMC's and not extracellularly. Alterations in HSP27 may give early evidence for intracellular differences in aortic aneurysm of patients with BAV and TAV. Whether HSP27 and the defined phosphoproteins have a specific role in BAV associated aortic dilatation remains to be elucidated.