On-X Valve Research Articles

Early Structural Valve Deterioration of Balloon Expandable Transcatheter Aortic Valve Leaflets Due to Intrinsic and Extrinsic Nodular Calcification in a Hemodialysis Patient: A Case Report

Abstract Background Several reports have shown that transcatheter aortic valves are comparable in durability to surgical aortic valves. However, early structural valve deterioration (SVD) is rarely reported to occur, especially in hemodialysis patients. Case Summary We present a case of rapidly progressive bioprosthetic aortic valve stenosis in a patient with end-stage renal disease (ESRD) secondary to diabetic nephropathy in an 83-year-old female admitted due to progressive dyspnea and orthopnea. A 23-mm sized SAPIEN3 bioprosthetic aortic valve showed normal function for the first year after transcatheter aortic valve implantation (TAVI), but then rapidly developed stenosis and required acute hospitalization for heart failure a year and a half after surgery. Emergent surgical aortic valve replacement (SAVR) with a 19-mm On-X valve (CryoLife, Kennesaw, GA, USA) was performed. Pathological examination of the explanted SAPIEN 3 valve demonstrated severely degenerated bioprosthetic pericardial leaflets with severe intrinsic and extrinsic nodular calcification, which could limit the leaflet motion. Discussion There is a lack of reports on the long-term procedural outcomes of TAVI in hemodialysis patients. The development of SVD in patients undergoing dialysis is multifactorial and has yet to be fully elucidated. In the presented case, the removed TAVI valve had severe extrinsic calcified nodules alongside a fibrin thrombus. Considering these pathological findings, antithrombotic therapy to prevent fibrin thrombus from adhering to the TAVI valve may be important to avoid early SVD.

Hemodynamic Comparison of the On-X and Top Hat Mechanical Aortic Valve Prostheses

BackgroundThere are limited data comparing hemodynamic valve function in mechanical aortic valve prostheses. This study compared the hemodynamic function of 2 commonly used mechanical aortic valve (AV) prostheses, the On-X (Artivion) and Top Hat (CarboMedics Inc) valves. MethodsThis study was a retrospective analysis of 512 patients who underwent AV replacement with the On-X (n = 252; 49%) or Top Hat (n = 260; 51%) mechanical valves between 2011 and 2019. Patients were matched on the basis of selected variables. Echocardiographic data were collected preoperatively and postoperatively over a median follow-up of 1.39 years. ResultsA total of 320 patients were matched, 160 patients in each group. Despite being matched for left ventricular outflow tract diameter, patients in the Top Hat group received a greater prevalence of smaller tissue annulus diameter valves (≤21 mm) (83% vs 38%; P < .001). Patients in the On-X group had longer aortic cross-clamp times (78 minutes vs 64 minutes; P < .001) during isolated aortic valve replacement. Discharge echocardiography showed no difference in the AV area index between both groups (1.00 cm2/m2 vs 1.02 cm2/m2; P = .377). During longer-term echocardiographic follow-up, the AV area index remained stable for both valves within their respective tissue annulus diameter groups (P = .060). ConclusionsThere was no difference between the 2 valves with respect to the AV area index at discharge, and hemodynamic function was stable during longer-term follow-up. The longer aortic cross-clamp time observed in the On-X group may indicate increased complexity of implantation compared with the Top Hat group.

Comparative Long-Term Clinical Performance of Mechanical Aortic Valve Prostheses

Aggregated data and long-term follow-up in national health data registers offer the opportunity to compare the performance of mechanical aortic prostheses within the same population. To investigate the clinical performance of mechanical aortic valve prostheses. This nationwide cohort study included all 5224 patients who underwent primary mechanical aortic valve replacement in Sweden between January 1, 2003, and December 31, 2018. Statistical analysis was performed between May and September 2023. Surgical aortic valve replacement with the On-X, Carbomedics, Bicarbon, Standard, Regent, Open Pivot, Masters, or Advantage valve models. The primary outcome was all-cause mortality, and secondary outcomes were reintervention, heart failure, major bleeding, stroke, and embolic events. Regression standardization was used to account for baseline differences. Overall, 5224 patients (mean [SD] age, 56.8 [11.7] years; 3908 men [74.8%]) were included. Total follow-up time was 43 982 person-years (mean [SD], 8.4 [4.6] years; maximum, 17.2 years). After regression standardization, there was a significant difference in 10-year mortality between the Carbomedics model group (17%; 95% CI, 15%-18%), Regent model group (17%; 95% CI, 13%-20%), and Standard model group (17%; 95% CI, 14%-19%) compared with the Bicarbon model group (27%; 95% CI, 21%-34%). In this cohort study of mechanical valve surgical aortic replacement outcomes in Sweden, the rate of all-cause mortality was higher in the Bicarbon group than in the Carbomedics, Regent, and Standard model groups. These findings warrant further research on the long-term clinical performance of the Bicarbon valve.

Benefits of On-X Mitral Valve Replacement in Cases of Infective Endocarditis

Purpose. Mitral valve replacement (MVR) is necessary in cases of severe infective endocarditis (IE). Because the On-X valve is expected to be effective in reducing prosthesis-associated turbulent blood flow, we investigated the hemodynamic efficacy of the On-X valve when used for MVR in cases of mitral valve IE. Methods. We compared postoperative outcomes between two groups of patients who underwent MVR for IE: 13 given an On-X valve and 27 given an SJM valve. Results. There were no in-hospital deaths. Late death occurred in 6 cases, all in the SJM group (P=0.1520). The incidence of late postoperative atrial fibrillation was relatively low in the On-X group (1 case vs. 10 cases, P=0.068). Univariate analysis showed an association between the effective orifice area and postoperative atrial fibrillation. The effective orifice area and indexed effective orifice area were significantly larger in the On-X group at 2.8 ± 0.7 cm2 vs. 2.2 ± 0.5 cm2 (P=0.007) and 1.8 ± 0.5 cm2/m2 vs. 1.4 ± 0.4 cm2 (P=0.003), respectively. Conclusions. The suggested reduction in left atrial load attributed to the use of the On-X valve in MVR for IE may reduce the incidence of postoperative atrial fibrillation.

In vivo performance of a tri-leaflet mechanical heart valve prosthesis in an ovine model.

We present the long-term results of a trileaflet (Triflo) versus bileaflet (On-X) mechanical valve in both aortic and pulmonary positions in a sheep model. The Triflo valve was implanted in 21 female sheep in aortic (n = 8) and pulmonary position (n = 13). The On-X valve was implanted in 7 female sheep in aortic (n = 1) and pulmonary (n = 6) positions. No antithrombotic medication of any kind was given postoperatively. In the aortic group, survival cohorts were 3 and 5 months. In the pulmonary group, survival cohorts were 10 and 20 weeks. Valve performance was assessed using haematology, echocardiography and acoustic measurements combined with post-mortem pathology analysis of the downstream organs. The mean gradients were lower for the Triflo valve in both pulmonary [4.30 mmHg (3.70-5.73) vs 6.80 mmHg (4.63-7.96), P = 0.012] and aortic [5.1 mmHg (4.2-7.7) vs 10.7 mmHg (8.7-12.9), P = 0.007] positions. Peak gradients were lower for the Triflo valve in both pulmonary [8.05 mmHg (6.75-10.23) vs 13.15 mmHg (9.20-14.76), P = 0.005] and aortic [8.7 mmHg (7.5-12.5) vs 16.5 mmHg (14.2-19.6), P = 0.009] positions. In both positions, leaflets and housing surface were free from any deposits macro- and microscopically and comparable to nonimplanted control valves. Peripheral organs showed no signs of thrombo-embolic damage. Biochemical and haematological were comparable to preoperative. The closing click sound pressure level of the Triflo was significantly lower in both aortic [108.4 sound pressure level (102.0-115.7) vs 111.7 sound pressure level (105.5-117.0), P < 0.001] and pulmonary [103.6 sound pressure level (99.1-108.9) vs 118.5 sound pressure level (116.7-120.2), P < 0.001] position. Preliminary in vivo results of the Triflo valve are promising in both aortic and pulmonary positions in an ovine model. Excellent haemodynamics, stable long-term function, low valve noise and no thrombo-embolic events in the absence of antithrombotic medication lay the foundation to a future clinical first-in-man trial.

Leaflet fracture and escape from an On-X mechanical mitral valve in a child: a case report

Abstract Background Leaflet escape is a rare complication of mechanical heart valves. The following case is the first report of leaflet escape from an On-X mechanical mitral valve in a child. Case summary A 12-year-old boy presented with acute pulmonary oedema one year after mitral valve replacement with an On-X valve for rheumatic heart disease. Transoesophageal echocardiogram diagnosed an absent mechanical mitral valve leaflet and severe mitral regurgitation for which the patient successfully underwent urgent mitral valve replacement. Computed tomography located fragments of the embolised mitral valve leaflet at the bifurcation of the abdominal aorta and within the right common iliac artery. In the absence of impaired lower limb perfusion, the leaflet fragments were left in situ. He was discharged without complication and remains asymptomatic three months post-discharge. Discussion Leaflet fracture and escape is a known but rare complication of mechanical valve prostheses. The first-line investigation for suspected mechanical valve dysfunction is transoesophageal echocardiogram which elicited the diagnosis on this occasion.

Assessment of clinical, paraclinical characteristics of patients receiving concomitant mitral and aortic valve replacement with On-X mechanical prosthesis at Bach Mai Hospital

Objectives: To investigate clinical and paraclinical characteristics of patients undergoing concomitant mitral and aortic valve replacement with On-X mechanical valve at Bach Mai Hospital. Subjects and methods: This was a non-controlled, prospective, descriptive study on 100 patients with severe aortic and mitral diseases undergoing concomitant aortic and mitral valve replacement with On-X valve. Clinical and paraclinical parameters were selected based on Vietnam National Heart Association and ACC/AHA guidelines. Results: Clinical manifestations included history of rheumatic heart disease (70.0%), NYHA class II (36.0%), NYHA class III (64.0%), atrial fibrillation (67.0%). Echocardiography showed dilated left ventricle (LVEDd 55.2 ± 8.9 mm, LVEDs 37.3 ± 8.1 mm), preserved left ventricular ejection fraction (63.9 ± 9.5%), moderately pulmonary arterial hypertension (47.2 ± 13.8 mmHg), and dilated left atrium (53.8 ± 10.5 mm). Conclusion: Most patients undergoing concomitant On-X aortic and mitral prosthetic valve replacement presented with moderate and severe heart failure, dilated left ventricle and left atrium, and increased pulmonary arterial pressure.&#x0D; * Keywords: Mitral and aortic valve replacement; On-X valve.

PROSE: Prospective Randomized Trial of the On-X Mechanical Prosthesis and the St Jude Medical Mechanical Prosthesis Evaluation: Part 2: Study results—prostheses, positions, and economic development

ObjectivesThe Prospective Randomized On-X Mechanical Prosthesis Versus St Jude Medical Mechanical Prosthesis Evaluation (PROSE) trial purpose was to investigate whether a current-generation mechanical prosthesis (On-X; On-X Life Technologies/Artivion Inc) reduced the incidence of thromboembolic-related complications compared with a previous-generation mechanical prosthesis (St Jude Medical Mechanical Prosthesis; Abbott/St Jude Medical). This second report documents the valve-related complications by individual prostheses and by Western and Developing populations. MethodsThe PROSE trial study was conducted in 28 worldwide centers and incorporated 855 subjects randomized between 2003 and 2016. The study enrollment was discontinued on August 31, 2016. The study protocol, and analyses of 10 demographic variables and 24 risk factors were published in detail in 2021. ResultsThe total patient population (N = 855) included patients receiving an On-X valve (n = 462) and a St Jude Medical valve (n = 393). The overall freedom evaluation showed no differences at 5 years between the prostheses for thromboembolism or for valve thrombosis. There were also no differences in mortality. There were several differences between Developing and Western populations. The freedom relations at 5 years for mortality favored Western over Developing populations. Valve thrombosis was differentiated by position and site: aortic < mitral (P = .007) and Western < Developing (P = .005). In the mitral position there were no cases in Western populations, whereas there were 8 in Developing populations (P = .217). ConclusionsThe On-X valve and St Jude Medical valve performed equally well in the study with no differences found. The only differentiation occurred with valve thrombosis in the mitral position more than the aortic position and occurring in Developing more than Western populations. The occurrence of valve thrombosis was also related to a younger population possibly due to anticoagulation compliance based on record review.

Aortic valve replacement using On-X valve in a child postorthotopic heart transplantation.

A 20-month-old girl presented with severe dilated cardiomyopathy and decompensated congestive cardiac failure. Despite escalating inotropic and mechanical ventilation support, she required placement on extracorporeal membrane oxygenation and transfer to the transplant centre in Newcastle, England. She was placed on biventricular assist device and then Berlin Heart but failed to show any recovery of ventricular function. She underwent orthotopic heart transplantation at 2 years of age. She developed bacterial endocarditis with Enterococcus faecalis resulting in severe aortic valve regurgitation requiring aortic valve replacement with a 19 mm On-X valve (Airtivion) 11 days after her transplant. Given the size of the donor heart, it was possible to implant a 19-mm valve in this 12 kg child with minimal risk of patient prosthesis mismatch. She was anticoagulated with warfarin (On-X valve INR 2-3 for first 3 months; INR 1.5-2.0 thereafter). Although she suffered several other post-operative complications, including malabsorption, nasojejunal feeding, liver dysfunction, vertebral fractures, renal impairment and renal calcification, and need for repeat opening of her tracheostomy site following her initial decannulation, her aortic valve function has remained stable.

The role of mechanical valves in the aortic position in the era of bioprostheses and TAVR: Evidence-based appraisal and focus on the On-X valve

Patients who need a prosthetic aortic heart valve may decide, working with their cardiologist and cardiac surgeon, among a variety of options: surgical or transcatheter approach, bioprosthetic or mechanical valve, or a Ross procedure if suitable to their age and anatomy. This review article examines the evidence for survival benefit with mechanical aortic valves, discusses bioprosthetic structural valve degeneration and its consequences, and considers the risks of redo aortic valve surgery or subsequent valve-in-valve (ViV) transcatheter intervention. It highlights the unique characteristics of the On-X aortic valve, including the US Food and Drug Administration approved and American College of Cardiology/American Heart Association guideline supported reduced anticoagulation target INR of 1.5 to 2.0, and discusses the PROACT Xa trial comparing apixaban vs warfarin anticoagulation. The choice of prosthetic valve should be individualized, carefully considering each patient's unique circumstances. In that context, the On-X aortic valve offers a potential lifetime solution without need for a repeat operation, while minimizing the risks of long-term anticoagulation. In an era of enthusiasm for bioprosthetic and transcatheter-based approaches, the option of a second-generation bileaflet mechanical valve with optimized hemodynamics—the On-X aortic valve—may well align with patient expectations.

Factor Xa Inhibitors for Patients after Mechanical Heart Valve Replacement?

Patients with a mechanical heart valve need a lifelong anticoagulation due to the increased risk of valve thrombosis and thrombo-embolism. Currently, vitamin K antagonists (VKA) are the only approved class of oral anticoagulants, but relevant interactions and side effects lead to a large number of patients not achieving the optimal therapeutic target international normalized ration (INR). Therefore, steady measurements of the INR are imperative to ensure potent anticoagulation within a distinctive range. Direct oral anticoagulants (DOACs) with newer agents could serve as a possible alternative to VKAs in this patient cohort. DOACs are approved for several indications, e.g., atrial fibrillation (AF). They only have a minor interaction potential, which is why monitoring is not needed. Thereby, DOACs improve the livability of patients in need of chronical anticoagulation compared with VKAs. In contrast to dual platelet inhibition using aspirin in combination with an ADP receptor antagonist and the direct thrombin inhibitor dabigatran, the oral factor Xa inhibitors apixaban and rivaroxaban show promising results according to current evidence. In small-scale studies, factor Xa inhibitors were able to prevent thrombosis and thrombo-embolic events in patients with mechanical heart valves. Finally, DOACs seem to represent a feasible treatment option in patients with mechanical heart valves, but further studies are needed to evaluate clinical safety. In addition to the ongoing PROACT Xa trial with apixaban in patients after aortic On-X valve implantation, studies in an all-comer collective with rivaroxaban could be promising.

Permanent pacemaker implantation after On-X surgical aortic valve replacement: SWEDEHEART observational study

ObjectiveBioprosthetic aortic valves with an extended subannular component, such as transcatheter valves, exert increased compression on the cardiac conduction system and increase the risk for permanent pacemaker implantation. It is...

Long-Term Clinical Outcomes of the On-X Mechanical Prosthetic Valve in the Aortic or Mitral Position - A Single-Center Experience of up to 20 Years' Follow up.

This study evaluated the long-term outcomes for up to 20 years after On-X mechanical valve implantation in the left side of the heart.Methods and Results:Between 1999 and 2015, 861 patients (mean age=51.6±10.9 years) who underwent prosthetic valve replacement using the On-X valve in the aortic or mitral position were enrolled (aortic=344, mitral=325, double=192). The mean clinical follow-up duration was 10.5±5.3 (median 10.9) years. Operative mortality occurred in 26 patients (3.0%), and linearized late cardiac mortality was 0.9%/patient-year without an intergroup difference. Linearized thromboembolism, bleeding, prosthetic valve endocarditis, non-structural valve deterioration (NSVD), and reoperation rates were 0.8%/patient-year, 0.6%/patient-year, 0.2%/patient-year, 0.5%/patient-year, and 0.5%/patient-year, respectively. Prosthetic valve endocarditis was more frequent after double valve replacement than after aortic or mitral valve replacement (P=0.008 and 0.005, respectively). NSVD and reoperation rates were significantly lower aortic valve replacement than after mitral or double valve replacement (P=0.001 and 0.002, P=0.001 and <0.001, respectively). Valve replacement in the mitral position was the only risk factor for NSVD (hazard ratio [95% confidence interval]=5.247 [1.608-17.116], P=0.006). On-X valve implantation in the left side heart had favorable clinical outcomes with acceptable early and late mortality and a low incidence of prosthetic valve-related complications. Particularly in the aortic position, the On-X valve had better long-term non-structural durability.

In-vivo Evaluation of a Novel Surgical Heart Valve Prosthesis Designed to Be Durable, Anticoagulant-free and Silent

Objective: Heart valves prostheses still face limitations: reoperations with tissue valves or lifelong anticoagulation with mechanical valves. The Triflo valve, a tri-leaflet valve made of high-resistant bio-inert materials, aimed at overcoming these limitations. We studied safety and performance in a chronic sheep model. Methods: The Triflo valve (size 21mm) was implanted in two models: 90 days in aortic position (n=7) and 70 days in pulmonary position (n=4). In the pulmonary model, On-X valves (n=2) were used as control. After 7 days of low-molecular-weight heparin, no further anticoagulant was administered. Serial blood testing, echocardiography, acoustic measurements, fluoroscopy and autopsy were done. Results: The Triflo valve demonstrated excellent surgical handling. There were one aborted procedure and one early death in the aortic study, both unrelated to the prosthesis. All other sheep (n=9) recovered fast and remained in excellent clinical condition until the scheduled sacrifice. In aortic position, we observed low peak and mean gradients (8.1+/-2.7 and 4.8+/-1.9 mmHg), high effective orifice area (2.3+/-0.2 cm2), no valvular regurgitation, and perfect left ventricular function. At explantation, the surface of all Triflo valves was clean, without any valve thrombosis. All major organs were free from thrombo-embolic (TE) damage. In pulmonary position, leaflet mobility of all valves remained also normal and no TE-damage was found in the lungs. Hematological parameters were stable without any sign of hemolysis. On-X valves in pulmonary position functioned well, but generated significantly louder acoustic signals (p < 0.05). Conclusions: The Triflo valve showed safety and effectiveness in both aortic and pulmonary position. These favorable in-vivo results, with excellent hemodynamic behavior and stable long-term function even in the absence of anticoagulants, demonstrate that this valve can proceed to first-in-human studies.

Early Hemodynamic Profile after Aortic Valve Replacement — A Comparison between Three Mechanical Valves

IntroductionThere are scarce data comparing different mechanical valves in the aortic position. The objective of this study was to compare the early hemodynamic changes after aortic valve replacement between ATS, Bicarbon, and On-X mechanical valves.MethodsWe included 99 patients who underwent aortic valve replacement with mechanical valves between 2017 and 2019. Three types of mechanical valves were used, On-X valve (n=45), ATS AP360 (n=32), and Bicarbon (n=22). The mean prosthetic valve gradient was measured postoperatively and after six months.ResultsPreoperative data were comparable between groups, and there were no differences in preoperative echocardiographic data. Pre-discharge echocardiography showed no difference between groups in the ejection fraction (P=0.748), end-systolic (P=0.764) and end-diastolic (P=0.723) diameters, left ventricular mass index (P=0.348), aortic prosthetic mean pressure gradient (P=0.454), and indexed aortic prosthetic orifice area (P=0.576). There was no difference in the postoperative aortic prosthetic mean pressure gradient between groups when stratified by valve size. The changes in the aortic prosthetic mean pressure gradient of the intraoperative period, at pre-discharge, and at six months were comparable between the three prostheses (P=0.08). Multivariable regression analysis revealed that female gender (beta coefficient -0.242, P=0.027), body surface area (beta coefficient 0.334, P<0.001), and aortic prosthetic size (beta coefficient -0.547, P<0.001), but not the prosthesis type, were independent predictors of postoperative aortic prosthetic mean pressure gradient.ConclusionThe three bileaflet mechanical aortic prostheses (On-X, Bicarbon, and ATS) provide satisfactory early hemodynamics, which are comparable between the three valve types and among different valve sizes.

Effect of Aortic Wall Deformation with Healthy and Calcified Annulus on Hemodynamic Performance of Implanted On-X Valve.

In this research, the hemodynamic performance of a 23-mm On-X bileaflet mechanical heart valve (BMHV) was investigated with the realistic geometry model of the valve and the deformable aorta in accelerating systole. In addition, the effect of ascending aorta flexibility and aortic annulus calcification on the complex blood flow characteristics were investigated. The geometry of the aorta is derived from the medical images, and the Ogden model has been utilized for the mechanical behavior of the ascending aorta. The 3D numerical simulation by a two-way Fluid-Structure Interaction (FSI) analysis using the Arbitrary Lagrangian-Eulerian (ALE) method was performed throughout the accelerating systolic phase. The dynamics of the leaflets are investigated, and blood flow characteristics such as velocities, vorticities as well as viscous and turbulent shear stress were precisely captured in the flow domain specifically in the hinge region. Streamline results are in accordance with the previously reported data, which show that the flared On-X valves inlet yields a more uniform flow in accelerating systole. Simulations show that aorta flexibility or valve annulus calcification causes variations up to 7% in maximum fluid velocity and 20% in Turbulence Kinetic Energy (TKE). In this study, the complex flow field characteristics in the new generation of BMHVs considering aorta flexibility with healthy and calcified annulus were investigated. It was found that the blood flow around the hinges region is in the danger of hemolysis and platelet activation and subsequently thromboembolism. Furthermore, the results show that similar to vessel wall deformation, considering the probable annulus calcification after valve replacement is also essential.

The Prospective Randomized On-X Valve Anticoagulation Clinical Trial (PROACT): Lower is better, but is it good enough?

Due to their durability, mechanical prostheses are frequently used for aortic valve replacement (AVR) in young adults. However, these valves are thrombogenic and require lifelong anticoagulation. Over the last few decades, efforts have been made towards the lowering of INR targets in an effort to reduce bleeding events without influencing the thromboembolic risk. The Prospective Randomized On-X Valve Anticoagulation Clinical Trial (PROACT) was designed to compare standard versus low anticoagulation targets in high-risk patients undergoing mechanical AVR with the ON-X prosthesis.

A turbulence in vitro assessment of On-X and St Jude Medical prostheses

ObjectiveThe objective of this study was to investigate and compare the hemodynamic and turbulence characteristics upon implantation of St Jude Medical (SJM) (St Jude Medical, St Paul, Minn) and On-X (On-X Life Technologies, Kennesaw, Ga) bileaflet mechanical valves. Both valves are considered highly successful bileaflet mechanical valves characterized by good clinical outcomes despite their numerous design differences. Although thromboembolism remains the main disadvantage of bileaflet mechanical valves, On-X valves have been shown to need less anticoagulation therapy. MethodsHemodynamic assessment of a 23-mm On-X bileaflet mechanical valve and a 23-mm bileaflet SJM valve implanted in an aortic root was performed under pulsatile physiologic conditions. Time-resolved and phase-locked particle-image-velocimetry images and high-speed imaging data were acquired. Pressure gradients, effective orifice areas, dimensionless area index, leaflet position tracking, velocity, and principal Reynolds shear stress were calculated. ResultsPressure gradient for the On-X valve was 4.15 ± 0.099 mm Hg versus 4.75 ± 0.048 mm Hg for SJM (P < .001). Effective orifice area for the On-X valve was 2.61 ± 0.045 cm2 versus 2.36 ± 0.022 cm2 for SJM (P < .001). Area index was higher with SJM (0.87 ± 0.008) than with On-X (0.73 ± 0.013) (P < .001). On-X showed fluctuating leaflet behavior during systole, whereas SJM leaflets were stable. At peak systole, the maximal velocity with On-X was 1.86 m/s versus 2.33 m/s with SJM. Reynolds shear stress was higher with On-X compared with SJM at peak systole (95 vs 72 Pa). Higher velocity fluctuation was noted with the On-X valve. ConclusionsThis study shows that despite the design differences that characterize the On-X valve, the hemodynamic and turbulence parameters were not necessarily improved compared with SJM.

A novel trileaflet mechanical heart valve: first in vitro results.

Heart valve prostheses are the therapy of choice for patients with severe heart valve diseases. Two types of prostheses that can be implanted in patients are available: biological and mechanical. Though mechanical heart valves have some disadvantages like necessity of life-long anticoagulation, biological heart valve prostheses often necessitate reinterventions due to limited durability. Therefore, a new trileaflet mechanical heart valve was developed, featuring hinges in the systolic flow with the aim of function and thrombogenicity. We first compared the new trileaflet mechanical heart valve to conventional bileaflet heart valves (St. Jude Medical and On-X valves) in vitro. Haemodynamic measurements were performed in a pulse duplicator system, and clot formation was examined with an implemented method using enzyme-activated milk as the test medium. Haemodynamic measurements showed the largest effective orifice areas and smallest pressure gradients for the trileaflet prosthesis compared to the bileaflet valve. Opening and closing characteristics of the trileaflet valve and of the St. Jude Medical valve were comparable. Clotting tests depicted only minor isolated deposits for the new trileaflet valve whereas the bileaflet valves showed distinct clots in the area of the hinge in all experiments. Haemodynamic and clotting tests showed improvements for the new trileaflet valve compared to common bileaflet valves. The off-wall systolic position of the hinges, which eluded adverse flow areas, was a major advantage of the new valve.

Outcomes after mechanical aortic valve replacement in children and young adults with congenital heart disease

ObjectivesThere are little recent data on the outcomes of mechanical aortic valve replacement (AVR) in children and young adults with congenital aortic valve disease. We sought to review the survival and associated thromboembolic or bleeding complications after mechanical AVR at a single center. MethodsData were retrospectively collected for 121 patients undergoing prosthetic AVR from 2000 to 2014. Kaplan-Meier estimates and Cox proportional hazards were employed. ResultsMedian age at AVR was 16 years (interquartile range, 12-22.8 years). The valves implanted were the St Jude valve (St Jude Medical Inc, St Paul, Minn) in 79 patients (62%), the On-X valve (On-X Life Technologies Inc, Austin, Tex) in 45 patients (35%), and CarboMedics (Sorin SpA, Milan, Italy) in 3 patients (2.4%). Median valve size was 23 mm (range, 21-25 mm). There were 5 early deaths (3.9%). Median follow-up was 5 years (range, 1.6-9.2 years; 600 patient-years). There were 14 deaths during follow-up. Survival was 90.6% ± 2.8% at 1 year, 85.4% ± 3.7% at 5 years, and 81.5% ± 4.5% at 10 years. Freedom from aortic valve reoperation was 98% ± 1.4% at 1 and 5 years, 91.5% ± 3.9% at 7 years, and 78.4% ± 6.9% at 10 years and at latest follow-up. Univariable analysis identified younger age, lower weight, and use of a 16-mm CarboMedics valve as predictors of reoperation. Valve sizes of 16 or 17 mm have a significantly higher risk of reoperation compared with larger valves (log-rank test, P < .001). At multivariable analysis, only younger age was a significant independent predictor of reoperation (hazard ratio, 0.84; 95% confidence interval, 0.71-0.99; P = .038). All patients were treated with warfarin to a goal international normalized ratio of 2.0 to 3.0. Four patients (3.1%; 0.66% per patient-year) had thromboembolic complications, and 5 patients (3.9%; 0.83% per patient-year) had bleeding events during follow-up. ConclusionsMechanical AVR in patients with congenital heart disease has excellent short- and midterm outcomes. Younger age was an independent predictor of reoperation.