Aortic Valve Deformity Research Articles

Outlet Ventricular Septal Defect: Impact of Surgery on the Late Aortic and Pulmonary Valve Functions

This study retrospectively evaluated long-term post-operative aortic and pulmonary valve functions in outlet ventricular septal defects. We evaluated aortic regurgitation and pulmonary regurgitation using pre- and post-operative echocardiograms. Overall, 158 patients who underwent intracardiac repair due to outlet ventricular septal defects with aortic valve deformity or congestive heart failure were included. The median follow-up period was 7years (interquartile range: 0-17years), without deaths or pacemaker implantations. The age, weight, ventricular septal defect size, and mild aortic regurgitation at surgery were factors associated with post-operative residual aortic regurgitation. Mild pulmonary regurgitation was observed in 12%, 30%, and 40% of patients 5, 10, and 15years after surgery, respectively. There were no significant differences in age and weight at which surgery was performed between patients with mild pulmonary regurgitation and those with less than mild pulmonary regurgitation. However, the number of sutures across the pulmonary valve was associated with post-operative pulmonary regurgitation (P < 0.01). As some patients with mild pre-operative aortic regurgitation may not improve even after surgery, early surgical intervention is necessary when aortic regurgitation appears. Some patients may develop post-operative pulmonary regurgitation in the long term, suggesting the need for careful follow-up.

Long-Term Outcomes of Surgical Repair for Ventricular Septal Defect in Adults.

Data of the outcomes of ventricular septal defect (VSD) closure in adults are limited to establish recommendations. Therefore, we reviewed our experience with surgical VSD closure in adult patients. We retrospectively reviewed 152 patients who underwent surgical VSD closure between January 1996 and April 2020. The median age of the patients was 30.5 [interquartile range (IQR) 23.1-42.7] years. The median follow-up duration was 10.9 (IQR 4.8-16.1) years. VSDs were classified according to the Society of Thoracic Surgeons classification as type 2 (n = 66, 43.4%), type 1 (n = 59, 38.8%), and type 4 (n = 27, 17.8%). Aortic cusp prolapse (n = 86, 56.6%) and aortic valve regurgitation (AR, n = 75, 49.3%) were the most common indications for surgical closure. Four patients underwent late reoperation (2.6%) due to AR, infective endocarditis and residual VSD. In the log-rank test, preoperative trivial or more degree of AR (P = 0.004) and coronary cusp deformity (P = 0.031) was associated with late moderate or greater degree of AR. Preoperative moderate or greater AR was associated with reoperation (P = 0.047). Only concomitant aortic valve (AV) repair at the time of VSD closure was a significant risk factor for late significant AR progression in the multivariable analysis. VSD closure in adults can be performed with low mortality and morbidity rates. AR can progress after VSD closure because the aortic cusp may have irreversible damage from long-standing shunt flow exposure. We conclude that VSD with AV deformity or AR in adults should be treated aggressively before disease progression with irreversible damage occurs.

Using Discrete Multiphysics Modelling to Assess the Effect of Calcification on Hemodynamic and Mechanical Deformation of Aortic Valve

This study proposes a 3D particle-based (discrete) multiphysics approach for modelling calcification in the aortic valve. Different stages of calcification (from mild to severe) were simulated, and their effects on the cardiac output were assessed. The cardiac flow rate decreases with the level of calcification. In particular, there is a critical level of calcification below which the flow rate decreases dramatically. Mechanical stress on the membrane is also calculated. The results show that, as calcification progresses, spots of high mechanical stress appear. Firstly, they concentrate in the regions connecting two leaflets; when severe calcification is reached, then they extend to the area at the basis of the valve.

Aortic Valve Deformation During Transcatheter Mitral Valve Replacement

A 79-year-old man underwent transcatheter mitral valve replacement (TMVR) with the Tendyne system (Abbott, Santa Clara, California) for moderate-to-severe mitral regurgitation (MR) owing to bileaflet prolapse in the middle-lateral scallop ([Figure 1A][1], [Video 1][2]). Pre-operative computed

A transverse isotropic constitutive model for the aortic valve tissue incorporating rate-dependency and fibre dispersion: Application to biaxial deformation.

This paper presents a continuum-based transverse isotropic model incorporating rate-dependency and fibre dispersion, applied to the planar biaxial deformation of aortic valve (AV) specimens under various stretch rates. The rate dependency of the mechanical behaviour of the AV tissue under biaxial deformation, the (pseudo-) invariants of the right Cauchy-Green deformation-rate tensor Ċ associated with fibre dispersion, and a new fibre orientation density function motivated by fibre kinematics are presented for the first time. It is shown that the model captures the experimentally observed deformation of the specimens, and characterises a shear-thinning behaviour associated with the dissipative (viscous) kinematics of the matrix and the fibres. The application of the model for predicting the deformation behaviour of the AV under physiological rates is illustrated and an example of the predicted σ-λ curves is presented. While the development of the model was principally motivated by the AV biomechanics requisites, the comprehensive theoretical approach employed in the study renders the model suitable for application to other fibrous soft tissues that possess similar rate-dependent and structural attributes.

Characterization of mechanical properties of pericardium tissue using planar biaxial tension and flexural deformation.

Flexure is an important mode of deformation for native and bioprosthetic heart valves. However, mechanical characterization of bioprosthetic leaflet materials has been done primarily through planar tensile testing. In this study, an integrated experimental and computational cantilever beam bending test was performed to characterize the flexural properties of glutaraldehyde-treated bovine and porcine pericardium of different thicknesses. A strain-invariant based structural constitutive model was used to model the pericardial mechanical behavior quantified through the bending tests of this study and the planar biaxial tests previously performed. The model parameters were optimized through an inverse finite element (FE) procedure in order to describe both sets of experimental data. The optimized material properties were implemented in FE simulations of transcatheter aortic valve (TAV) deformation. It was observed that porcine pericardium TAV leaflets experienced significantly more flexure than bovine when subjected to opening pressurization, and that the flexure may be overestimated using a constitutive model derived from purely planar tensile experimental data. Thus, modeling of a combination of flexural and biaxial tensile testing data may be necessary to more accurately describe the mechanical properties of pericardium, and to computationally investigate bioprosthetic leaflet function and design.

Ascending to descending aorta extraanatomic bypass for coarctation of aorta

Objective To summarize the treatment of 10 aortic coarctation cases , who receive the surgery from ascending aorta to thoracic descending aorta with the prosthetic graft, discuss the valuable and appliable of this method. Methods Cardiac surgery, Chinese Acdemy of Medical Sciences, Peking Union Medical College Hospital department treated 10 patients who got the aortic coarctation from Jan. 2006 to Dec. 2015 Seven male patients and 3 cases of female patients consist of the sample, aged from 14 to 35 years old, the median age was 27. One cases consolidated aortic valve deformity and aortic root expansion, the others were simple aortic coarctation.Their upper limbs blood pressure was 20 mmHg higher compared with the low limb. Meanwhile, there was no sign of surgery contraindication. Ten cases received this operation under cardiopulmonary bypass situation.And the patient who consolidate aortic valve deformity and aortic root expansion receive the Bentall surgery at the same time. Results There was no death during perioperative time, no spinal cord ischemic and other serious complications. Those patients went back to outpatient department after discharging from hospital 3 to 6 months.The differential pressure between upperlimbs and low limbs were less than 20 mmHg, and the CTA results indicated no aneurysms. Conclusion Using artificial blood vessels to make a graft from the ascending aorta to the descending aorta is an effective method for treatment of thoracic aorta. Key words: Aortic coarctation; Bypass; Cardiovascular abnormalities; Surgical procedures, operative

Machine learning-based 3-D geometry reconstruction and modeling of aortic valve deformation using 3-D computed tomography images.

To conduct a patient-specific computational modeling of the aortic valve, 3-D aortic valve anatomic geometries of an individual patient need to be reconstructed from clinical 3-D cardiac images. Currently, most of computational studies involve manual heart valve geometry reconstruction and manual finite element (FE) model generation, which is both time-consuming and prone to human errors. A seamless computational modeling framework, which can automate this process based on machine learning algorithms, is desirable, as it can not only eliminate human errors and ensure the consistency of the modeling results but also allow fast feedback to clinicians and permits a future population-based probabilistic analysis of large patient cohorts. In this study, we developed a novel computational modeling method to automatically reconstruct the 3-D geometries of the aortic valve from computed tomographic images. The reconstructed valve geometries have built-in mesh correspondence, which bridges harmonically for the consequent FE modeling. The proposed method was evaluated by comparing the reconstructed geometries from 10 patients with those manually created by human experts, and a mean discrepancy of 0.69mm was obtained. Based on these reconstructed geometries, FE models of valve leaflets were developed, and aortic valve closure from end systole to middiastole was simulated for 7 patients and validated by comparing the deformed geometries with those manually created by human experts, and a mean discrepancy of 1.57mm was obtained. The proposed method offers great potential to streamline the computational modeling process and enables the development of a preoperative planning system for aortic valve disease diagnosis and treatment.

Simulated transcatheter aortic valve deformation: A parametric study on the impact of leaflet geometry on valve peak stress.

In this study, we developed a computational framework to investigate the impact of leaflet geometry of a transcatheter aortic valve (TAV) on the leaflet stress distribution, aiming at optimizing TAV leaflet design to reduce its peak stress. Utilizing a generic TAV model developed previously [Li and Sun, Annals of Biomedical Engineering, 2010. 38(8): 2690-2701], we first parameterized the 2D leaflet geometry by mathematical equations, then by perturbing the parameters of the equations, we could automatically generate a new leaflet design, remesh the 2D leaflet model and build a 3D leaflet model from the 2D design via a Python script. Approximately 500 different leaflet designs were investigated by simulating TAV closure under the nominal circular deployment and physiological loading conditions. From the simulation results, we identified a new leaflet design that could reduce the previously reported valve peak stress by about 5%. The parametric analysis also revealed that increasing the free edge width had the highest overall impact on decreasing the peak stress. A similar computational analysis was further performed for a TAV deployed in an abnormal, asymmetric elliptical configuration. We found that a minimal free edge height of 0.46 mm should be adopted to prevent central backflow leakage. This increase of the free edge height resulted in an increase of the leaflet peak stress. Furthermore, the parametric study revealed a complex response surface for the impact of the leaflet geometric parameters on the peak stress, underscoring the importance of performing a numerical optimization to obtain the optimal TAV leaflet design. Copyright © 2016 John Wiley & Sons, Ltd.

Echocardiographic Findings of Congenital Valvular Heart Disease in Young Athletes

Here the author shows two cardiac ultrasound images of otherwise healthy young athletes recorded during sports preparticipation screening. Figure 1 shows the typical aortic valve deformity called, “hockey stick”, of the bicuspid aortic valve magnified by parasternal long axis view, while Figure 2 shows the typical finding of type I supra-valvular pulmonic stenosis, involving main pulmonary artery, visualized by parasternal short axis view. Despite the congenital heart valvular anomalies, both athletes were considered fit to sports competition. Congenital cardiac anomalies are frequent in young athletes, however in most cases the physical fitness is not compromised. Echocardiography is the mainstay in the diagnosis and follow-up assessment of young athletes with congenital heart disease.

Efficacy and experience in right ventricular pacing-percutaneous balloon aortic valvuloplasty

To evaluate the efficacy and experience in right ventricular pacing-percutaneous balloon aortic valvuloplasty (RVP-PBAV) for congenital aortic stenosis (AS). A total of sixteen children with AS accepted the treatment with RRVP-PBAV. The patients were at ages 6 months to 15 years, their median age was 5.4 years. Their body weight was between 8.5 and 59.0 kg, average (22.3 ± 16.5) kg. The gradient pressure across the aortic valve was measured for all the patients and aortic regurgitation was observed. The follow-up time ranged from 1 month to 5.5 years. All patients underwent RVP-PBAV successfully. The ratios of balloon/valve were 0.86 to 1.12. The gradient pressure varied from preoperative Δp = (96 ± 32) mmHg (1 mmHg = 0.133 kPa) to the immediate postoperative ΔP = (41 ± 26) mmHg, (P < 0.05). One case had postoperative restenosis, and 3 cases were complicated with bicuspid aortic valve deformity. The treatment with RVP-PBAV for congenital aortic stenosis is safe and reliable. Rapid ventricular pacing is a safe procedure to stabilize the balloon during balloon aortic valvuloplasty and may decrease the incidence of aortic insufficiency.

2C18 心拍に伴う大動脈弁の変形が弁硬化症発症に及ぼす影響 : 弁に生じた応力・ひずみ分布と硬化症好発部位との関係(GS7-2:循環器系のバイオメカニクス(2))

2C18 心拍に伴う大動脈弁の変形が弁硬化症発症に及ぼす影響 : 弁に生じた応力・ひずみ分布と硬化症好発部位との関係(GS7-2:循環器系のバイオメカニクス(2))

A Model of Left Ventricular Dysfunction Complicated by CAWS Arteritis in DBA/2 Mice

It was reported previously that a Candida albicans water-soluble fraction (CAWS), including a mannoprotein and β-glucan complex, has strong potency in inducing fatal necrotizing arteritis in DBA/2 mice. In this study, histopathological changes and cardiac function were investigated in this system. One mg/day of CAWS was given to DBA/2 mice via peritoneal injection for five days. The CAWS-treated DBA/2 mice were induced aortitis and died at an incidence of 100% within several weeks. Histological findings included stenosis in the left ventricular outflow tract (LVOT) and severe inflammatory changes of the aortic valve with fibrinoid necrosis. Cardiomegaly was observed and heart weight increased 1.62 fold (P < 0.01). Echocardiography revealed a severe reduction in contractility and dilatation of the cavity in the left ventricle (LV): LV fractional shortening (LVFS) decreased from 71% to 38% (P < 0.01), and the LV end-diastolic diameter (LVDd) increased from 2.21 mm to 3.26 mm (P < 0.01). The titer of BNP mRNA increased in the CAWS-treated group. Severe inflammatory changes resulting from CAWS brought about lethal LV dysfunction by aortic valve deformation with LVOT stenosis. This system is proposed as an easy and useful experimental model of heart failure because CAWS arteritis can be induced by CAWS injection alone.

Evaluation of Stress Strain Patterns in a Stentless Aortic Valve and Its Leaflets

Objective: To design a new trileaflet aortic valve and investigate its mechanical behavior using finite ele- ment methods. Background: Quantification of aortic valve deformation during cardiac cycle is essential in understanding normal and pathological valvular function and eventually in the design of valves. We have designed and analyzed a new tissue valve model to investigate the mechanics of the valve and its components. Methods: Steps involves in 3D CAD based geometric modeling of a trileaflet aortic valve and the effects of different component dimensions on the mechanical behavior of valve is presented in this paper. Conceptual designing of individual components was used to build the total geometric model. Different physiological pressures were applied on the valve model and its deformation patterns were studied. Results: A new geometric model of a trileaflet aortic valve was designed. Its mechanical behavior was studied. Geometric analysis and simulation of these models enhanced the designer to optimize the geometry suitable for performance during and after implantation. Conclusion: The geometry-based model presented here allows determining quickly if the new set of valve component dimensions results in a functional valve. This is of great interest to designers of new prosthetic heart valve models, as well as to surgeons involved in valve- sparing surgery.

Unforeseen Consequences of Therapy With Continuous-Flow Pumps

> For use almost can change the stamp of nature. > > — Hamlet , Act III, Scene IV Hamlet's statement may well be applied to the marked alteration in normal mammalian physiology introduced by the use of left ventricular assist devices (LVADs), particularly the nonpulsatile devices. This alteration of the “stamp of nature” has led to changes in the normal circulatory physiology not previously encountered in the field of medicine. Two unanticipated consequences of the clinical application of LVAD technology—acquired aortic valve insufficiency (AI) and acquired von Willebrand syndrome (VWS)—are reported in this issue of Circulation: Heart Failure . Articles see pp 668 and 675 The report by Cowger et al1 quantifies a single-center experience with acquired AI after implantation of both the pulsatile HeartMate XVE (HM-XVE) and the nonpulsatile HeartMate II (HM-II) LVAD (Thoratec Corporation, Pleasanton, Calif). These investigators used echocardiography to study 78 patients who received the HeartMate XVE (n=25) or HeartMate II (n=53) LVAD between 2004 and 2008. They performed 315 studies at set time intervals and graded AI and aortic valve opening according to classic echocardiographic methodology. Trends in the development of AI were assessed in the group as a whole and were then compared by device type. Because this was a single-center study, the numbers available for follow-up evaluation were limited (49 patients at 6 months, 29 patients at 12 months, 13 patients at 18 months, and 5 patients at 24 months). However, an increase in both the development and the severity of AI was noted during this period. The grade of moderate-to-severe AI was approximately 11% at 6 months, 26% at 12 months, and 51% at 18 months. Compared with patients with the HM-XVE device, those with the HM-II pump had an increased incidence and severity of AI; however, in no patient was the AI severe enough to require intervention. The authors …

307 Contemporary treatment of isolated vsd in children: amplatzer vs surgical closure

Isolated hemodynamically significant Ventricular septal defects (VSD) were once solely surgical lesions. Since the introduction of percutaneous devices, the management of isolated VSD has evolved. In our center, Amplatzer devices have been implanted since 1998 and for selected isolated perimembranous and muscular VSD since 2002. We therefore reviewed our institutional practice selectively using percutaneous and surgical approaches. We retrospectively reviewed clinical, electrocardiographic and echocardiographic data of all isolated percutaneous and surgical VSD closures since 2002. Pre-operative (preop), immediate post-operative (postop) in addition to 1 month, 6 month and annual postop results were studied. The following table summarizes demographic data: 37 patients who underwent percutaneous closures and 34 who treated surgically, mean follow-up 42 months. Percutanous group were older ( p < 0.01 ) and bigger ( p<0.001 ). The VSD gradient preop was lower in the surgical group ( p < 0.004 ), thus patients were in greater clinical heart failure. There was no mortality in either group. At follow-up there were no differences in the incidence of residual VSD ( p = 0.34 ). 2 patients with perimembranous VSD and pre-existing aortic valve deformity increased its level to moderate post-Amplatzer implantation versus none in the surgical group ( p = 0.45 ). A permanent pacemaker was implanted for complete heart block following post device closure of a perimembranous VSD in one patient and none in the surgical group. The surgical results are excellent in this sicker patient population, as reported in the literature. Patient selection remains a challenge to avoid post-percutaneous intervention complications such as heart block and aortic insufficiency in the perimembranous VSD patients. Percutaneous closure of isolated VSD, which avoids some morbidity of open heart surgery should however remain part of the therapeutic armamentarium. Results table Amplatzer group median (min-max) Surgical group median (min-max) P value Age (year) 12,83 (0,67-21,33) 1,41 (0,16-5,66) p<0,001 Weight (Kg) 24,6 (5,35-77,9) 5,00 (4,1-18,5) p<0,001 VSD size (mm) 5,7 (2,1-19) 11,00 (9,00-12,00) p<0,02 VSD Gradient (mmHg) 87 (54-138) 33 (25-66) p<0,004 LVEF (%) 59 (52,21-68,87) 60 (56,42-72,52) NS CPB duration (min.) N.A. 78,5 (70-150) - Aortic cross-clamp (min.) N.A. 55,5 (36-125) - Device size (mm) 8 (6-14) N.A. -

Ruptured sinus of Valsalva aneurysm in two patients with subarterial ventricular septal defect

Rupture of a sinus of Valsalva aneurysm (SVA) is a rare, but life-threatening, event and requires immediate recognition and intervention. We present two previously healthy and physically active patients who were 12 and 33 years of age when rupture of a right coronary SVA into the right ventricle occurred. A subarterial ventricular septal defect (VSD) was detectable in both patients. Cardiac surgery involved VSD closure as well as reconstruction of the aortic valve. Considering complications of subarterial VSD, such as aortic cusp prolapse, aortic insufficiency or SVA, we suggest close follow-up and surgical closure of the VSD in case of any aortic valve deformity.

INVITED COMMENTARY

Aortic valve deformity becomes an overwhelming concern for those with an isolated subarterial ventricular septal defect who survive their early years without symptoms. Aortic valve prolapse may accompany peri-membranous defect with outlet extension when the aortic valve overrides the septum and makes the aortic cusp vulnerable to injury by the shunt flow. This study shows that the incidence of valve prolapse may be higher than what is generally believed, especially among Asians, and it warrants periodic aortic valve monitoring before surgery. The same management principle probably applies to all subtypes, although aortic deformity is relatively subtle with muscular outlet defects. This exception is partly due to the smaller size of the defect and possibly due to the fact that the midportion of the cusp is usually affected with a muscular outlet defect rather than the commissural portion in other subtypes. It is now generally believed that the cusp deformity does not progress once the ventricular septal defect is closed adequately. However, aortic regurgitation does progress in some patients after repair. We now know that significant aortic regurgitation develops in 20% to 30% of patients 10 to 20 years after repair of tetralogy with subarterial ventricular septal defect. This is caused either by placing the patch directly beneath the aortic valve and jeopardizing its integrity or simply by technical failure. It is important to delineate the precise mechanism of progressive aortic regurgitation after repair in this patient subset to determine the best closure method (ie, whether or not to use a patch to close subarterial defect) and the timing for surgery. In addition, subaortic ridge is sometimes associated with these defects. The ridge usually does not cause obstruction before operation; however, it can cause significant subaortic narrowing after repair. This is another anatomic feature that can jeopardize long-term outcome and also warrants further study.

Analysis of indications for surgical closure of subarterial ventricular septal defect without associated aortic cusp prolapse and aortic regurgitation

Subarterial ventricular septal defect (VSD) is relatively common in Orientals. We reviewed the outcome of 214 patients (137 males) who were followed for 8.6 ± 5.2 years (range 0.1 to 24.3) and addressed the issue regarding the necessity and optimum timing of closing subarterial defects before development of aortic valve deformities. Demographic data, transthoracic and transesophageal echocardiographic findings, cardiac catheterization results, and operative findings were reviewed. Kaplan-Meier actuarial analysis was performed to assess the development of aortic valve complications over time. Seventy-five patients with heart failure and pulmonary hypertension underwent surgical closure of VSD at the age of 2.4 ± 2.9 years. No patient had aortic cusp prolapse before operation and none developed aortic cusp prolapse or aortic regurgitation (AR) on follow-up. In contrast, of the 139 asymptomatic patients managed conservatively, 102 (73%) developed aortic cusp prolapse, 78% of whom (80 of 102) developed AR. The prevalence of aortic cusp prolapse and AR at 1, 5, 10, and 15 years old was 8%, 30%, 64%, and 83%, and 3%, 24%, 45%, and 64%, respectively. Significant prolapse or AR prompted surgical closure of VSD with (n = 22) or without (n = 26) valvoplasty in 48 of 102 patients (47%). The size of the VSD was significantly larger in patients with heart failure (9.6 ± 3.3 mm) or aortic cusp prolapse (11.7 ± 4.1 mm) compared with those without heart failure (4.5 ± 1.4 mm, p <0.001). All patients with aortic cusp prolapse and all but 1 with heart failure had a defect size of ≥5 mm. In conclusion, subarterial VSD of ≥5 mm should be closed as early as possible to prevent development of aortic cusp prolapse and AR. Asymptomatic patients with small defects <5 mm could be managed conservatively.

Influence of surgery on aortic valve prolapse and aortic regurgitation in doubly committed subarterial ventricular septal defect

Doubly committed subarterial ventricular septal defects should be closed surgically once aortic valve deformity is present before the onset of aortic regurgitation.