Quadricuspid pulmonary valve and left pulmonary artery aneurysm in an asymptomatic patient assessed by cardiovascular MRI

We present a coincidental finding of quadricuspid pulmonary valve and left pulmonary artery aneurysm. As both the pulmonary valve and the pulmonary trunk with its main branches are hard to visualise with cardiac ultrasound, most abnormalities described so far are from autopsy series. With the increasing use of CMR and its excellent potential for visualising both pulmonary valve and pulmonary arteries, we believe more cases will be discovered in the near future. Although pulmonary artery aneurysm are rare, timely detection may prevent lethal bleeding.     

Comparative in vitro study of bileaflet and tilting disk valve behavior in the pulmonary position

A study of mechanical heart valve behavior in the pulmonary position as a function of pulmonary vascular resistance is reported for the St. Jude Medical bileaflet (SJMB) valve and the MedicalCV Omnicarbon (OTD) tilting disk valve. Tests were conducted in a pulmonic mock circulatory system and impedance was varied in terms of system pulmonary vascular resistance (PVR). An impedance spectrum was found using instantaneous pulmonary artery pressure and flow rate curves. Both valves fully opened and closed at and above a nominal PVR of 3.0 mmHg/L/min. The SJMB valve was prone to leaflet bounce at closure, but otherwise completely closed, at settings above and below this nominal setting. At PVR values at and below 2.0 mmHg/L/min, the SJMB valve exhibited two types of leaflet aberrant behavior: single leaflet only closure while the other leaflet fluttered, and incomplete closure where both leaflets flutter but neither remain fully closed. The OTD valve fully opened and closed to a PVR value of 1.6 mmHg/L/min. At lower values, the valve did not close. Valves designed for the left heart can show aberrant behavior under normal conditions as pulmonary valves.     

Numerical simulation of cardiovascular dynamics with healthy and diseased heart valves

This paper presents a new concentrated parameter model for cardiovascular dynamics that includes an innovative model of heart valve dynamics, which is embedded in the overall model of the four chambers of the heart and the systemic and pulmonary circulation loops. The heart chambers are described with a variable elastance model, and the systemic and pulmonary loops are described with modified Windkessel models. In modelling the heart valve dynamics, the various factors that influence the valve motion are examined, and the governing differential equation for valve motion is derived. The heart valve model includes the influence of the blood pressure effect, the friction effect from the tissue, and from blood motion. As improvement from previous works, the contribution of the blood vortex effect in the vicinity of the valve leaflets to valve motion is specially considered. The proposed model is then used in simulation of healthy and certain pathological conditions such as mitral valve stenosis and aortic regurgitation. The predicted results agree well with results illustrated in cardiology textbooks.     

SEVERE PULMONARY HYPERTENSION WITH SIGNIFICANT "A" DIP ON PULMONIC VALVE ECHOCARDIOGRAM

A patient with severe pulmonary hypertension and no evidence of right ventricular failure who had a 4 mm "a" dip on the pulmonic valve echocardiogram is reported. Although other echocardiographic abnormalities suggesting pulmonary hypertension were recorded in our patient, the normal "a" dip of the pulmonic valve in the absence of right ventricular failure appears to be an exception to previously reported findings. We suggest motion of the entire pulmonary artery as an explanation for this phenomenon.     

Extracellular Adenine Nucleotide Catabolism in Heart Valves

Enzymes of extracellular nucleotide catabolism, such as ecto-nucleoside triphosphate diphosphohydrolase (eNTPD), ecto-5′-nucleotidase (e5NT) and ecto-adenosine deaminase (eADA), control extracellular concentrations of adenine nucleotides and adenosine, furthermore in that way regulate inflammation, immune response, and platelets aggregation. In valves, disturbances of these processes may lead to their dysfunction and calcification. The aim of this study was to analyze the distribution of enzymes, which are engaged in extracellular nucleotide metabolism on the surface of pig aortic and pulmonary valves in relation to activities in the vessel wall. Activity of e5NT was two times higher on the surface of the aortic valve in comparison to the aorta. The same relation between activity of this enzyme in the pulmonary valve and pulmonary artery can be observed. In contrast, eADA activity on the valve surface is much lower than in the vessel wall. No significant differences were observed between the activity of eNTPD on the valve and the vessel surface. This highlights that pattern of enzymes activities favors the production and retention of adenosine on the valve surface and that its alterations could play a role in valve pathology.     

Are heart valves from donors over 65 years of age morphologically suitable for transplantation?

Since there is no upper age limit for general organ donation, unlike heart valve donation, and since a quarter of all organ donors are 65 years and older, we examined whether the heart valves from these donors are suitable as allografts. In the period 1999–2004 the aortic valve and pulmonary valve of 100 organ donors above 65 years of age were examined to establish whether they would have been suitable as valve grafts. To compare the valve grafts above and below the age limit of 65 years, we used data on the aortic and pulmonary valves of 380 organ donors below the age limit in the same time period. Examination of the 200 heart valves showed that – just like valves from donors below the age limit – 100 of them would have met the medical quality standards for transplantation, which discriminate among optimal, suitable and unsuitable tissue morphology. The morphological suitability of the aortic valves decreases rapidly during the 4th decade of life and near to the age limit only 6% of them are accepted as grafts. The rate of potentially acceptable aortic valve grafts from organ donors aged over 65 years of 15% is also small. By contrast, the pulmonary valves are not affected by age-related tissue changes that might reduce their transplantability. The predominant majority (85%) of potential pulmonary valve grafts from organ donors over 65 years of age fulfilled the acceptance criteria, half of them (48%) even showing good tissue quality. In light of these results the age limit was raised to 70 years in 2005.     

Precise Stent Placement Using the New Siemens Artis Zeego 3D Rotation Angiography in a Stenosis of a Shelhigh Pulmonary Conduit

Stenting of the Shelhigh pulmonary conduit was performed 2 years after a Ross procedure because of a stenosis of the distal segment. We used the new Siemens Artis Zeego technology. A precise placement of the stent to release the stenosis within the distal segment simultaneously retaining a competent valve was possible by using the Dyna-computed tomography technology. The early onset of a stenosis of the Shelhigh xenograft in the pulmonary position is alarming, thus, its use can not be recommended for a replacement of the pulmonary valve.     

Recurrent acute pulmonary oedema after aortic and mitral valve surgery due to trachea malacia and obstructive sleep apnoea syndrome

In this report we describe a patient with recurrent episodes of acute pulmonary oedema after aortic and mitral valve surgery. The first episode of pulmonary oedema was caused by mitral valve dysfunction. The second episode of pulmonary oedema was not clearly associated with a mitral valve problem, but reoperation was performed in the absence of another explanation. After the third episode of acute pulmonary oedema occurred, the diagnosis of obstructive sleep apnoea syndrome (OSAS) was considered and confirmed. After starting treatment with continuous positive airway pressure (CPAP) during his sleep the patient had no further episodes of acute respiratory failure. Our case demonstrates that acute pulmonary oedema after cardiothoracic surgery can be caused or at least be precipitated by OSAS and should be suspected in patients with unexplained episodes of (recurrent) pulmonary oedema. (Neth Heart J 2008;16:310-2.)     

RECONSTRUCTION OF THE RIGHT VENTRICULAR OUTFLOW TRACT WITH A POSTERIOR MONOCUSP VALVE

Reconstruction of the right ventricular outflow tract with sections of pericardium or with Dacron patches often leads to pulmonary regurgitation. This report presents a technique for minimizing regurgitation by creating a single posterior leaflet using the patient's own valve. After incision of the pulmonary artery and valvular ring, the valve is brought forward to cover the opening of the reconstructed pulmonary artery. This time-saving technique avoids the risk of calcification which usually accompanies the use of homografts and heterografts.     

改良Nikaidoh手术治疗合并肺动脉瓣狭窄的右室双出口

目的：总结改良Nikaidoh手术治疗右心室双出口（DORV）患者的临床经验,以提高手术疗效。方法：2例先天性心脏病右心室双出口伴肺动脉瓣狭窄行改良Nikaidoh手术,游离主动脉根部及冠状动脉,重建左心室流出道,以带单瓣牛心包片补片重建肺动脉及右心室流出道。结果：术后患者紫绀消失,复查心脏彩超仅有轻度肺动脉瓣关闭不全,未发现左、右心室流出道梗阻,康复出院。结论：采用改良Nikaidoh手术治疗伴肺动脉瓣狭窄的右室双出口,术后可获得良好的血流动力学效果,早期临床结果满意。     

The Role of Rubella in the Etiology of Supravalvular Aortic Stenosis

The possibility of an etiological relationship between rubella embryopathy and sporadic forms of supravalvular aortic stenosis is considered. A case is presented of a patient with rubella embryopathy and supravalvular aortic stenosis associated with pulmonary valvular and peripheral pulmonary artery stenosis, bicuspid aortic valve, aortic valve stenosis and subendothelial myocardial fibrosis. A review of the literature revealed many clinical and pathological features common to both syndromes. The hypothesis that rubella virus produced germ-cell mutation and subsequent persistence of rubella in the zygote produced further fetal damage is presented to explain these observations.     

Fluid–structure interaction in a fully coupled three-dimensional mitral–atrium–pulmonary model

This paper aims to investigate detailed mechanical interactions between the pulmonary haemodynamics and left heart function in pathophysiological situations (e.g. atrial fibrillation and acute mitral regurgitation). This is achieved by developing a complex computational framework for a coupled pulmonary circulation, left atrium and mitral valve model. The left atrium and mitral valve are modelled with physiologically realistic three-dimensional geometries, fibre-reinforced hyperelastic materials and fluid–structure interaction, and the pulmonary vessels are modelled as one-dimensional network ended with structured trees, with specified vessel geometries and wall material properties. This new coupled model reveals some interesting results which could be of diagnostic values. For example, the wave propagation through the pulmonary vasculature can lead to different arrival times for the second systolic flow wave (S2 wave) among the pulmonary veins, forming vortex rings inside the left atrium. In the case of acute mitral regurgitation, the left atrium experiences an increased energy dissipation and pressure elevation. The pulmonary veins can experience increased wave intensities, reversal flow during systole and increased early-diastolic flow wave (D wave), which in turn causes an additional flow wave across the mitral valve (L wave), as well as a reversal flow at the left atrial appendage orifice. In the case of atrial fibrillation, we show that the loss of active contraction is associated with a slower flow inside the left atrial appendage and disappearances of the late-diastole atrial reversal wave (AR wave) and the first systolic wave (S1 wave) in pulmonary veins. The haemodynamic changes along the pulmonary vessel trees on different scales from microscopic vessels to the main pulmonary artery can all be captured in this model. The work promises a potential in quantifying disease progression and medical treatments of various pulmonary diseases such as the pulmonary hypertension due to a left heart dysfunction.

     

In vitro study of flow regulation for pulmonary insufficiency

Given the tolerance of the right heart circulation to mild regurgitation and gradient, we study the potential of using motionless devices to regulate the pulmonary circulation. In addition, we document the flow performance of two mechanical valves. A motionless diode, a nozzle, a mechanical bileaflet valve, and a tilting disk valve were tested in a pulmonary mock circulatory system over the normal human range of pulmonary vascular resistance (PVR). For the mechanical valves, regurgitant fractions (RFs) and transvalvular pressure gradients were found to be weak functions of PVR. On the low end of normal PVR, the bileaflet and tilting disk valves fluttered and would not fully close. Despite this anomaly, the regurgitant fraction of either valve did not change significantly. The values for RF and transvalvular gradient measured varied from 4 to 7% and 4 to 7 mm Hg, respectively, at 5 lpm for all tests. The diode valve was able to regulate flow with mild regurgitant fraction and trivial gradient but with values higher than either mechanical valve tested. Regurgitant fraction ranged from 2 to 17% in tests extending from PVR values of 1 to 4.5 mm Hg/lpm at 5 lpm and with concomitant increases in gradient up to 17 mm Hg. The regurgitant fraction for the nozzle increased from 2 to 23% over the range of PVR with gradients increasing to 18 mm Hg. The significant findings were: (1) the mechanical valves controlled regurgitation at normal physiological cardiac output and PVR even though they failed to close at some normal values of PVR and showed leaflet flutter; and (2) it may be possible to regulate the pulmonary circulation to tolerable levels using a motionless pulmonary valve device.     

Early experience with the Venus p‑valve for percutaneous pulmonary valve implantation in native outflow tract

Introduction

The Venus p?valve (MedTech, Shanghai, China) is a self-expanding percutaneous heart valve designed to be implanted in a native patched right ventricle outflow tract. The worldwide clinical experience with this valve is just beginning and the results have so far been encouraging. We present our initial early experience implanting the Venus p?valve in the native right ventricle outflow tract of patients with Tetralogy of Fallot repaired with a transannular patch.

Methods

In 10 selected patients a procedure for percutaneous pulmonary valve implantation was performed using the Venus p?valve. The patients mean age was 32 years (13–57), mean weight 59.6?kg (40–80). All patients had Tetralogy of Fallot with moderate to severe pulmonary regurgitation and an indication for pulmonary valve replacement.

Results

The implantation procedure was successful in all the patients resulting in an immediately functional valve. No procedure-related complications were observed. Follow-up after 12 months (4–21) resulted in an improvement in NYHA class. There was a reduction of the mean right ventricle diastolic volume from 139?ml/m² (105–179) to 78?ml/m² (65–100) and improvement in the regurgitation fraction from 42% (29–58) to 1% (0–5), as seen on routine cardiac magnetic resonance 6 months after the implantation. No stent fractures have been observed so far.

Conclusion

Percutaneous pulmonary valve implantation with the Venus p?valve resulted in a safe and effective procedure. The valve has predictable and sustained functional competence, resulting in clinical improvement in the patients.

     

Combined usage of inhaled and intravenous milrinone in pulmonary hypertension after heart valve surgery

Secondary pulmonary hypertension is a frequent condition after heart valve surgery. It may significantly complicate the perioperative management and increase patients' morbidity and mortality. The treatment has not been yet completely defined principally because of lack of the selectivity of drugs for the pulmonary vasculature. The usage of inhaled milrinone could be the possible therapeutic option. Inodilator milrinone is commonly used intravenously for patients with pulmonary hypertension and ventricular dysfunction in cardiac surgery. The decrease in systemic vascular resistance frequently necessitates concomitant use of norepinephrine. Pulmonary vasodilators might be more effective and also devoid of potentially dangerous systemic side effects if applied by inhalation, thus acting predominantly on pulmonary circulation. There are only few reports of inhaled milrinone usage in adult post cardiac surgical patients. We reported 2 patients with severe pulmonary hypertension after valve surgery. Because of desperate clinical situation, we decided to use the combination of inhaled and intravenous milrinone. Inhaled milrinone was delivered by means of pneumatic medication nebulizer dissolved with saline in final concentration of 0.5 mg/ml. The nebulizer was attached to the inspiratory limb of the ventilator circuit, just before the Y-piece. We obtained satisfactory reduction in mean pulmonary artery pressure in both patients, and they were successfully extubated and discharged. Although it is a very small sample of patients, we conclude that the combination of inhaled and intravenous milrinone could be an effective treatment of secondary pulmonary hypertension in high-risk cardiac valve surgery patient. The exact indications for inhaled milrinone usage, optimal concentrations for this route, and the beginning and duration of treatment are yet to be determined.     

Analyzing valve interstitial cell mechanics and geometry with spatial statistics

Understanding cell geometric and mechanical properties is crucial to understanding how cells sense and respond to their local environment. Moreover, changes to cell mechanical properties under varied micro-environmental conditions can both influence and indicate fundamental changes to cell behavior. Atomic Force Microscopy (AFM) is a well established, powerful tool to capture geometric and mechanical properties of cells. We have previously demonstrated substantial functional and behavioral differences between aortic and pulmonary valve interstitial cells (VIC) using AFM and subsequent models of VIC mechanical response. In the present work, we extend these studies by demonstrating that to best interpret the spatially distributed AFM data, the use of spatial statistics is required. Spatial statistics includes formal techniques to analyze spatially distributed data, and has been used successfully in the analysis of geographic data. Thus, spatially mapped AFM studies of cell geometry and mechanics are analogous to more traditional forms of geospatial data. We are able to compare the spatial autocorrelation of stiffness in aortic and pulmonary valve interstitial cells, and more accurately capture cell geometry from height recordings. Specifically, we showed that pulmonary valve interstitial cells display higher levels of spatial autocorrelation of stiffness than aortic valve interstitial cells. This suggests that aortic VICs form different stress fiber structures than their pulmonary counterparts, in addition to being more highly expressed and stiffer on average. Thus, the addition of spatial statistics can contribute to our fundamental understanding of the differences between cell types. Moving forward, we anticipate that this work will be meaningful to enhance direct analysis of experimental data and for constructing high fidelity computational of VICs and other cell models.     

Minimally Invasive Mitral Valve Replacement Using the Valve-in-valve Technique

A 90-year-old woman with two previous mitral valve replacements, presented with pulmonary edema due to mitral regurgitation from degeneration of her bioprosthetic mitral valve. A minimally invasive approach was used to replace the bioprosthetic mitral valve. During surgery, the bioprosthetic valve was noted to be too adherent to the endocardium of the left atrium, making removal of the prosthesis not only difficult, but also potentially harmful. The new bioprosthetic valve was instead placed using a valve-in-valve approach.     

Networked-based characterization of extracellular matrix proteins from adult mouse pulmonary and aortic valves

A precise mixture of extracellular matrix (ECM) secreted by valvular cells forms a scaffold that lends the heart valve the exact mechanical and tensile strength needed for accurate hemodynamic performance. ECM proteins are a key component of valvular endothelial cell (VEC)-valvular interstitial cell (VIC) communication essential for maintenance of the valve structure. This study reports the healthy adult pulmonary and aortic valve proteomes characterized by LC-MS/MS, resulting in 2710 proteins expressed by 1513 genes, including over 300 abundant ECM proteins. Surprisingly, this study defines a distinct proteome for each semilunar valve. Protein-protein networking (PPN) was used as a tool to direct selection of proteomic candidates for biological investigation. Local PPN for nidogen 1 (Nid1), biglycan (Bgn), elastin microfibril interface-located protein 1 (Emilin-1), and milk fat globule-EGF factor 8 protein (Mfge8) were enriched with proteins essential to valve function and produced biological functions highly relevant to valve biology. Immunofluorescent investigations demonstrated that these proteins are functionally distributed within the pulmonary and aortic valve structure, indicative of important contribution to valve function. This study yields new insight into protein expression contributing to valvular maintenance and health and provides a platform for unbiased assessment of protein alterations during disease processes.     

Life-saving PTMC for critical calcific mitral stenosis in cardiogenic shock with balloon impasse

A 32-year-old male patient, a case of critical calcific mitral stenosis (following closed mitral valvotomy in 1989) was admitted for mitral valve replacement in September 2001. In hospital, he developed cardiogenic shock, pulmonary oedema and oliguria precluding surgery. An emergency percutaneous transatrial balloon mitral commissurotomy as a life-saving procedure in a valve with unfavourable morphology and 'balloon impasse' is discussed.