A parametric study on pulse duplicator design and valve hemodynamics.

BACKGROUND: In vitro assessment is mandatory for artificial heart valve development. This study aims to investigate the effects of pulse duplicator features on valve responsiveness, conduct a sensitivity analysis across valve prosthesis types, and contribute on the development of versatile pulse duplicator systems able to perform reliable prosthetic aortic valve assessment under physiologic hemodynamic conditions. METHODS: A reference pulse duplicator was established based on literature. Further optimization process led to new designs that underwent a parametric study, also involving different aortic valve prostheses. These designs were evaluated on criteria such as mean pressure differential and pulse pressure (assessed from high-fidelity pressure measurements), valve opening and closing behavior, flow, and regurgitation. Finally, the resulting optimized setup was tested under five different hemodynamic settings simulating a range of physiologic and pathologic conditions. RESULTS: The results show that both, pulse duplicator design and valve type significantly influence aortic and ventricular pressure, flow, and valve kinematic response. The optimal design comprised key features such as a compliance chamber and restrictor for diastolic pressure maintenance and narrow pulse pressure. Additionally, an atrial reservoir was included to prevent atrial-aortic interference, and a bioprosthetic valve was used in mitral position to avoid delayed valve closing effects. CONCLUSION: This study showed that individual pulse duplicator features can have a significant effect on valve's responsiveness. The optimized versatile pulse duplicator replicated physiologic and pathologic aortic valve hemodynamic conditions, serving as a reliable characterization tool for assessing and optimizing aortic valve performance.

Long-Term Outcomes of Mechanical Aortic Valve Replacement in Children.

When the options of aortic valve repair or the Ross procedure are not feasible or have been exhausted, mechanical aortic valve replacement (AVR) may provide a reliable and structurally durable alternative, but with the limitations of long-term anticoagulation, thrombosis risk and lack of valve growth potential. In this article, we review the longitudinal outcomes of mechanical AVR in children in our institution and compare them to those recently reported by others. From 1978 to 2020, 62 patients underwent mechanical AVR at a median age of 12.4 years (interquartile range (IQR): 8.6-16.8 years). The most common underlying diagnoses were: conotruncal anomalies (40%, 25/62), congenital aortic stenosis (16%, 10/62), rheumatic valve disease (16%, 10/62), connective tissue disease (8.1%, 5/62) and infective endocarditis (6.5%, 4/62). Thirty-two patients (52%, 32/62) had at least 1 prior aortic valve surgery prior to mechanical AVR. Early death was 3.2% (2/62). Median follow-up was 14.4 years (IQR: 8.4-28.2 years). Kaplan-Meier survival was 96.8%, 91.9%, 86.3%, and 81.9% at 1, 5, 10, and 20 years. On competing risk analysis, the proportion of patients alive without aortic valve reoperation at 1, 5, 10, and 20 years was 95.2%, 87.0%, 75.5% and 55.4%, respectively, while the proportion of patients that had aortic valve reoperation (with death as a competing event) at 1, 5, 10, and 20 years was 1.6%, 4.9%, 12.8%, and 28.5%, respectively. In conclusion, when the options of aortic valve repair or the Ross procedure are not feasible in children, mechanical AVR is an alternative, yet the long-term rates of mortality and need for aortic valve reoperation are of concern.

Evaluation and Management of Mechanical Heart Valve Dysfunction and Thrombosis.

PURPOSE OF REVIEW: Dysfunction and thrombosis of mechanical heart valves, although uncommon, represents a challenge that requires multidisciplinary expertise for diagnosis and management. The aim of this review is to summarize strengths and weaknesses of diagnostic methods and therapeutic strategies for this uncommon but potentially life-threatening pathology. RECENT FINDINGS: Expeditious diagnosis of mechanical valve thrombosis and exclusion of other diagnostic considerations, often with incorporation of multimodality imaging, can inform the best treatment strategy. Presentation of mechanical valve thrombosis can be asymptomatic or can include heart failure, life-threatening embolic events, or cardiogenic shock. Echocardiography, fluoroscopy and computed tomography are important in the evaluation of mechanical valve dysfunction. Therapeutic strategies for thrombosis include anticoagulation, systemic thrombolysis, and surgery. Choice of treatment depends on multiple factors including thrombus size, degree of valve dysfunction, clinical presentation, and available surgical expertise.

Long-Term Outcomes of Bioprosthetic and Mechanical Valve Replacement for Patients Aged between 50 and 70 Years.

Background: The choice between bioprosthetic and mechanical valves for aortic valve replacement (AVR) and mitral valve replacement (MVR) among patients aged 50-70 years is controversial. We compared the long-term outcomes of patients using bioprosthetic or mechanical valves to provide clinical evidence for valve selection. Methods: From 2002 to 2007, patients aged 50-70 years who underwent isolated AVR or MVR at the Fuwai Hospital were enrolled. After inverse probability-weighted (IPW) propensity balancing, we evaluated long-term mortality, stroke, and bleeding events between patients receiving mechanical and biological prostheses for MVR or AVR. Results: A total of 1639 patients were included in the study, including 1181 patients undergoing MVR (median follow-up: 11.6 years) and 458 patients undergoing AVR (median follow-up: 11.4 years). After IPW adjustment, there was no significant difference in long-term mortality and stroke rate between patients using bioprosthetic and mechanical valves for MVR [mortality: log-rank p = 0.802; stroke: log-rank p = 0.983] and AVR [mortality: log-rank p = 0.815; stroke: log-rank p = 0.537]. Landmark analysis at 12.5 years yielded significantly lower mortality in the patients receiving mechanical valves compared with bioprosthetic valves in the MVR cohort (p = 0.028). Patients receiving mechanical aortic valves displayed an increased risk of bleeding compared with those who received bioprosthetic aortic valves [Hazard Ratio (95% Confidence interval): 2.51 (1.06-5.93) p = 0.036]. Conclusions: For patients aged 50-70, there was no significant difference in overall long-term mortality between mechanical and bioprosthetic valve recipients. Patients receiving mechanical valves for MVR displayed lower mortality after 12.5 years follow-up. For AVR, bioprosthetic valves were associated with a lower risk of bleeding.

Readmissions After Surgical Aortic Valve Replacement: Influence of Prosthesis Type.

INTRODUCTION: Prosthesis choice during aortic valve replacement (AVR) weighs lifelong anticoagulation with mechanical valves (M-AVR) against structural valve degeneration in bioprosthetic valves (B-AVR). METHODS: The Nationwide Readmissions Database was queried to identify patients who underwent isolated surgical AVR between January 1, 2016 and December 31, 2018, stratifying by prothesis type. Propensity score matching was used to compare risk-adjusted outcomes. Readmission at 1 y was estimated with Kaplan-Meier (KM) analysis. RESULTS: Patients (n = 109,744) who underwent AVR (90,574 B-AVR and 19,170 M-AVR) were included. B-AVR patients were older (median 68 versus 57 y; P < 0.001) and had more comorbidities (mean Elixhauser score: 11.8 versus 10.7; P < 0.001) compared to M-AVR patients. After matching (n = 36,951), there was no difference in age (58 versus 57 y; P = 0.6) and Elixhauser score (11.0 versus 10.8; P = 0.3). B-AVR patients had similar in-hospital mortality (2.3% versus 2.3%; P = 0.9) and cost (mean: $50,958 versus $51,200; P = 0.4) compared with M-AVR patients. However, B-AVR patients had shorter length of stay (8.3 versus 8.7 d; P < 0.001) and fewer readmissions at 30 d (10.3% versus 12.6%; P < 0.001) and 90 d (14.8% versus 17.8%; P < 0.001), and 1 y (P < 0.001, KM analysis). Patients undergoing B-AVR were less likely to be readmitted for bleeding or coagulopathy (5.7% versus 9.9%; P < 0.001) and effusions (9.1% versus 11.9%; P < 0.001). CONCLUSIONS: B-AVR patients had similar early outcomes compared to M-AVR patients, but lower rates of readmission. Bleeding, coagulopathy, and effusions are drivers of excess readmissions in M-AVR patients. Readmission reduction strategies targeting bleeding and improved anticoagulation management are warranted in the first year following AVR.

Trans-right atrial access to the left ventricle for catheter ablation of ventricular tachycardia in patients with mechanical aortic and mitral valves.

The presence of mechanical heart valves in both aortic and mitral positions is a significant limitation for traditional left ventricular (LV) access, including retrograde transaortic and/or antegrade interatrial transseptal routes. We present a case of successful catheter ablation for ventricular tachycardia via a traditional transfemoral venous approach, which involves direct puncture of the inferior and medial aspect of the right atrium adjacent to the posteroseptal process of LV (PSPLV). Percutaneous trans-right atrial access to the left ventricle appears to be a safe and feasible method for catheter ablation of ventricular tachycardia in patients with mechanical aortic and mitral valves.

Comprehensive collection of COVID-19 related prosthetic valve failure: a systematic review.

Since the beginning of the SARS-CoV-2 (COVID-19) pandemic, correlation of venous thromboembolism (VTE) and COVID-19 infection has been well established. Increased inflammatory response in the setting of COVID-19 infection is associated with VTE and hypercoagulability. Venous and arterial thrombotic events in COVID-19 infection have been well documented; however, few cases have been reported involving cardiac valve prostheses. In this review, we present a total of eight cases involving COVID-19-related prosthetic valve thrombosis (PVT), as identified in a systematic review. These eight cases describe valve position (mitral versus aortic) and prosthesis type (bioprosthetic versus mechanical), and all cases demonstrate incidents of PVT associated with simultaneous or recent COVID-19 infection. None of these eight cases display obvious non-adherence to anticoagulation; five of the cases occurred greater than three years after the most recent valve replacement. Our review offers insights into PVT in COVID-19 infected patients including an indication for increased monitoring in the peri-infectious period. We explore valve thrombosis as a mechanism for prosthetic valve failure. We describe potential differences in antithrombotic strategies that may offer added antithrombotic protection during COVID-19 infection. With the growing population of valve replacement patients and recurring COVID-19 infection surges, it is imperative to explore relationships between COVID-19 and PVT.

Mechanical aortic valve prostheses offer a survival benefit in 50-65 year olds: AUTHEARTVISIT study.

BACKGROUND: The present population-based cohort study investigated long-term mortality after surgical aortic valve replacement (AVR) with bioprosthetic (B) or mechanical aortic valve prostheses (M) in a European social welfare state. METHODS: We analysed patient data from health insurance records covering 98% of the Austrian population between 2010 and 2018. Subsequent patient-level record linkage with national health data provided patient characteristics and clinical outcomes. Further reoperation, myocardial infarction, heart failure and stroke were evaluated as secondary outcomes. RESULTS: A total of 13,993 patients were analysed and the following age groups were examined separately: <50 years (727 patients: 57.77% M, 42.23% B), 50-65 years (2612 patients: 26.88% M, 73.12% B) and >65 years (10,654 patients: 1.26% M, 98.74% B). Multivariable Cox regression revealed that the use of B-AVR was significantly associated with higher mortality in patients aged 50-65 years compared to M-AVR (HR = 1.676 [1.289-2.181], p < 0.001). B-AVR also performed worse in a competing risk analysis regarding reoperation (HR = 3.483 [1.445-8.396], p = 0.005) and myocardial infarction (HR = 2.868 [1.255-6.555], p = 0.012). However, the risk of developing heart failure and stroke did not differ significantly after AVR in any age group. CONCLUSIONS: Patients aged 50-65 years who underwent M-AVR had better long-term survival, and a lower risk of reoperation and myocardial infarction. Even though anticoagulation is crucial in patients with M-AVR, we did not observe significantly increased stroke rates in patients with M-AVR. This evident survival benefit in recipients of mechanical aortic valve prostheses aged <65 years critically questions current guideline recommendations.

Biological Surgical Options in Young Patients for the Treatment of Severe Aortic Stenosis: Is the Jury Still Out? A Review.

Aortic interventions remain the most effective treatment for severe aortic stenosis. In the recent years, advances in bioprosthetics and newer data have reduced the cut-off age for the use of bioprosthetic valves in younger patients, but the debate on whether to favor mechanical valves in younger patients remains a constant, especially with the undesired effects and considerations of anticoagulation therapy with vitamin K antagonists in this age group. Other options like the Ross procedure are gaining traction, despite still being undervalued and necessitating expertise centers. Hemodynamic considerations and durability of these options are important to consider, especially in this age group. Regardless of the choice of the prosthesis, patient informed consent is paramount since the decision affects the lifetime management of their initial condition, and expectations given must remain realistic.

Echocardiographic Assessment of Prosthetic Valves.

Prosthetic valves are increasingly encountered in clinical practice. A grasp of the intricacies of the assessment and management of prosthetic valves is thus a crucial skillset for the practicing cardiologist. Echocardiography is the imaging modality of choice for the anatomic and functional evaluation of prosthetic valve. This document reviews the general features of prosthetic valves, echocardiographic identification of normally functioning and dysfunctional prosthetic valves as well as echocardiographic diagnosis of specific prosthetic valvular abnormalities.

Long-term outcomes of mechanical versus biological valve prosthesis in native mitral valve infective endocarditis.

Objectives. To study the long-term outcomes of mitral valve replacement with mechanical or biological valve prostheses in native mitral valve infective endocarditis patients. Desing. We conducted a retrospective, nationwide, multicenter cohort study with patients aged ≤70 years who were treated with mitral valve replacement for native mitral valve infective endocarditis in Finland between 2004 and 2017. Results. The endpoints were all-cause mortality, ischemic stroke, major bleeding, and mitral valve reoperations. The results were adjusted for baseline features (age, gender, comorbidities, history of drug abuse, concomitant surgeries, operational urgency, and surgical center). The median follow-up time was 6.1 years. The 12-year cumulative mortality rates were 36% for mechanical prostheses and 74% for biological prostheses (adj. HR 0.40; CI: 0.17-0.91; p = 0.03). At follow-up, the ischemic stroke had occurred in 19% of patients with mechanical prosthesis and 33% of those with a biological prosthesis (adj. p = 0.52). The major bleeding rates within the 12-year follow-up period were 30% for mechanical prosthesis and 13% for a biological prosthesis (adj. p = 0.29). The mitral valve reoperation rates were 13% for mechanical prosthesis and 12% for a biological prosthesis (adj. p = 0.50). Drug abuse history did not have a significant modifying impact on the results (interaction p = 0.51 for mortality and ≥0.13 for secondary outcomes). Conclusion. The use of mechanical mitral valve prosthesis is associated with lower long-term mortality compared to the biological prosthesis in non-elder native mitral valve infective endocarditis patients. The routine choice of biological mitral valve prostheses for this patient group is not supported by the results.

Treatment of valvular heart disease in young patients-"early evidence" versus "latest fashion".

Is the performance of locally manufactured mechanical valve prostheses relevant for modern cardiac surgery, in which mechanical valve replacement has become a rarity? This question comes to mind reading the article in this issue of the Journal demonstrating equal outcomes of the TTK Chitra tilting disk mechanical heart valve prostheses in comparison to the SJM bi-leaflet blockbuster. The evidence documenting efficacy of mechanical valve replacement stems from the early ages of cardiac surgery, but often demonstrates superior outcomes in terms of survival and hemodynamics. Yet, the latest fashion in the Western world consists biological choices in combination with new transcatheter techniques (valve in valve options) or the Ozaki or Ross procedures. As long-term results are often missing and documented advantages for mechanical valves stems from early evidence, the local emphasis of mechanical valve replacement may possibly result in superior individual prognoses compared to following the Western world's latest fashions. Individual patient information and decision making moves into focus.

Prosthetic cardiac valves: history and review of cardiac prostheses clinically available in Japan.

Recently developed prosthetic valves are reliable and essential for the treatment of valvular heart disease. The mechanical valve evolved remarkably following the introduction of pyrolite carbon material, which enabled the creation of a bileaflet form incorporated with a pivot mechanism. The improved durability of the biological valve is attributed mainly to the development of a tissue fixation process and anti-calcification treatments. However, optimal antithrombogenicity and durability have not yet been achieved for either prosthetic valve type. To select the most suitable prosthetic valve for each individual patient from among the many clinically available prosthetic valves, it is necessary to have a thorough understanding of the characteristics of each valve.

Engineering a New Polymeric Heart Valve Using 3D Printing-TRISKELION.

Background and Objectives: Developing a prosthetic heart valve that combines the advantageous hemodynamic properties of its biological counterpart with the longevity of mechanical prostheses has been a major challenge for heart valve development. Anatomically inspired artificial polymeric heart valves have the potential to combine these beneficial properties, and innovations in 3D printing have given us the opportunity to rapidly test silicone prototypes of new designs to further the understanding of biophysical properties of artificial heart valves. TRISKELION is a promising prototype that we have developed, tested, and further improved in our institution. Materials and Methods: STL files of our prototypes were designed with FreeCad 0.19.2 and 3D printed with an Agilista 3200W (Keyence, Osaka, Japan) using silicones of Shore hardness 35 or 65. Depending on the valve type, the support structures were printed in AR-M2 plastics. The prototypes were then tested using a hemodynamic pulse duplicator (HKP 2.0) simulating an aortic valve cycle at 70 bpm with 70 mL stroke volume (cardiac output 4.9 L/min). Valve opening cycles were visualized with a high-speed camera (Phantom Miro C320). The resulting values led to further improvements of the prototype (TRISKELION) and were compared to a standard bioprosthesis (Edwards Perimount 23 mm) and a mechanical valve (Bileaflet valve, St. Jude Medical). Results: We improved the silicone prototype with currently used biological and mechanical valves measured in our setup as benchmarks. The regurgitation fractions were 22.26% ± 4.34% (TRISKELION) compared to 8.55% ± 0.22% (biological) and 13.23% ± 0.79% (mechanical). The mean systolic pressure gradient was 9.93 ± 3.22 mmHg (TRISKELION), 8.18 ± 0.65 mmHg (biological), and 10.15 ± 0.16 mmHg (mechanical). The cardiac output per minute was at 3.80 ± 0.21 L/min (TRISKELION), 4.46 ± 0.01 L/min (biological), and 4.21 ± 0.05 L/min (mechanical). Conclusions: The development of a heart valve with a central structure proves to be a promising concept. It offers another principle to address the problem of longevity in currently used heart valves. Using 3D printing to develop new prototypes provides a fast, effective, and accurate way to deepen understanding of its physical properties and requirements. This opens the door for translating and combining results into modern prototypes using highly biocompatible polymers, internal structures, and advanced valve layouts.

Plaster pipes and crystalized graphite: Open transventricular transcatheter aortic valve replacement for failed mechanical aortic valve prostheses in the porcelain aorta.

Patients with a true porcelain aorta and a failed mechanical aortic valve prosthesis have limited treatment options. Using a hybrid of an open trans-ventricular approach with peripheral cardiopulmonary bypass and integration of transcatheter techniques this challenge can be overcome. Trans-ventricular mechanical valve extraction (with transcatheter endovascular occlusion and cardioplegia) followed by direct ante-grade transcatheter heart valve implantation offers a potential solution to this conundrum. The procedure described is a novel technique that allows for the effective treatment of patients with failed mechanical surgical aortic valve prostheses in the setting of an inoperable porcelain aorta. In addition, a collaborative integrated multi-disciplinary heart team environment is required for the management of these complex patients.

Comparison of Anticoagulation Quality between Acenocoumarol and Warfarin in Patients with Mechanical Prosthetic Heart Valves: Insights from the Nationwide PLECTRUM Study.

Vitamin K antagonists are indicated for the thromboprophylaxis in patients with mechanical prosthetic heart valves (MPHV). However, it is unclear whether some differences between acenocoumarol and warfarin in terms of anticoagulation quality do exist. We included 2111 MPHV patients included in the nationwide PLECTRUM registry. We evaluated anticoagulation quality by the time in therapeutic range (TiTR). Factors associated with acenocoumarol use and with low TiTR were investigated by multivariable logistic regression analysis. Mean age was 56.8 ± 12.3 years; 44.6% of patients were women and 395 patients were on acenocoumarol. A multivariable logistic regression analysis showed that patients on acenocoumarol had more comorbidities (i.e., ≥3, odds ratio (OR) 1.443, 95% confidence interval (CI) 1.081-1.927, p = 0.013). The mean TiTR was lower in the acenocoumarol than in the warfarin group (56.1 ± 19.2% vs. 61.6 ± 19.4%, p < 0.001). A higher prevalence of TiTR (<60%, <65%, or <70%) was found in acenocoumarol users than in warfarin ones (p < 0.001 for all comparisons). Acenocoumarol use was associated with low TiTR regardless of the cutoff used at multivariable analysis. A lower TiTR on acenocoumarol was found in all subgroups of patients analyzed according to sex, hypertension, diabetes, age, valve site, atrial fibrillation, and INR range. In conclusion, anticoagulation quality was consistently lower in MPHV patients on acenocoumarol compared to those on warfarin.

The Effect of Warfarin Administration Time on Anticoagulation Stability (INRange): A Pragmatic Randomized Controlled Trial.

PURPOSE: Without supporting evidence, clinicians commonly recommend that warfarin be taken in the evening. We conducted a randomized controlled trial to evaluate the effect of administration time (morning vs evening) on the stability of warfarin's anticoagulant effect. METHODS: A total of 236 primary care physicians serving 54 western Canadian communities mailed letters of invitation to all their warfarin-using patients. Eligible patients were community-dwelling warfarin users (any indication) with at least 3 months of evening warfarin use and no plans for discontinuation. Participants were randomized (by web-based allocation) to morning vs continued evening warfarin ingestion. We used the Rosendaal method to determine the proportion of time within therapeutic range (TTR) of the international normalized ratio (INR) blood test month 2 to 7 postrandomization vs the 6 months prerandomization. The primary outcome was the percent change in proportion of time outside target INR range (with an a priori minimum clinically important difference of ±20%). All analyses were intention to treat. RESULTS: Between March 8, 2015 and September 30, 2016, we randomized 109 participants to morning and 108 to evening warfarin use. TTR rose from 71.8% to 74.7% in the morning group, and from 72.6% to 75.6% in the evening group, for a change in TTR of 2.9% in the former vs 3.0% in the latter (difference, -0.1%; P = .97; 95% CI for the difference, -6.1% to 5.9%). The difference in percent change in proportion of time outside the therapeutic INR range (obtained via Hodges-Lehmann estimation of the difference in medians) was 4.4% (P = .62; 95% CI for the difference, -17.6% to 27.3%). CONCLUSIONS: Administration time has no statistically significant nor clinically important impact on the stability of warfarin's anticoagulant effect. Patients should take warfarin whenever regular compliance would be easiest.

Long-Term Outcomes and Echocardiographic Data After Aortic Valve Replacement With a 17-mm Mechanical Valve.

BACKGROUND: We investigated the long-term clinical and hemodynamic outcomes after aortic valve replacement (AVR) with a 17-mm mechanical valve.Methods and Results:Between January 2005 and December 2011, 80 patients with aortic stenosis underwent AVR with the 17-mm St. Jude Medical Regent prosthetic valve. Echocardiography was performed preoperatively, at discharge, and at follow-up, which was performed at least 2 years postoperatively (median interval, 7.3 years). Prosthesis-patient mismatch (PPM) was defined as an indexed effective orifice area <0.85 cm2/m2at discharge and occurred in 25 patients (31%). The median follow-up period was 8.7 years (100% complete). Overall in-hospital mortality was 2.5% (2 patients) with 27 late deaths (34%). The 5- and 10-year survival rates were 78.7% and 63.0%, respectively. Peripheral arterial disease and concomitant mitral valve repair were independent predictors of late mortality. The 5- and 10-year freedom from major adverse valve-related events (MAVRE) rates were 91.6% and 83.5%, respectively. PPM at discharge did not affect long-term survival, freedom from MAVRE, or freedom from heart failure. Echocardiographic data at follow-up revealed a significant reduction in the mean left ventricular mass index (LVMI). LVMI reduction observed at follow-up was similar between patients with and without PPM. CONCLUSIONS: AVR with the 17-mm mechanical prosthesis had acceptable long-term clinical and hemodynamic outcomes. Significant reduction in LVMI was observed regardless of PPM.

Outcomes of tissue versus mechanical aortic valve replacement in patients 50 to 70 years of age.

BACKGROUND: Societal guidelines suggest that aortic valve replacement (AVR) in patients age 50 to 70 years can be performed with either bioprosthetic or mechanical valves. This study reviewed outcomes between these valve types among patients aged 50 to 70 years undergoing AVR. METHODS: We examined adult patients 50 to 70 years undergoing isolated AVR with a mechanical or bioprosthetic valve at a single institution between 2010 and 2018. Kaplan-Meier analysis was used to evaluate longitudinal survival and multivariable Cox regression analysis was used for risk adjustment. A propensity-matched analysis was performed as well. RESULTS: A total of 723 patients underwent isolated AVR with 467 (64.6%) receiving a bioprosthetic valve. At baseline, patients undergoing bioprosthetic AVR were older (median 65 vs 60 years; P < .001). One-year survival was comparable, however, survival at 5 years was significantly higher among patients undergoing mechanical AVR (95.5% vs 82.6%; P = .010). Among the 196 matched pairs, bioprosthetic AVR was associated with an increased adjusted hazard for death (hazards ratio, 3.29; P < .001). Additionally, 5-year freedom from stroke and bleeding were similar following matching, though mechanical AVR was associated with a greater freedom from repeat valve intervention (97.5% vs 92.9%; P = .020). CONCLUSION: In patients age 50 to 70, mechanical AVR is associated with improved long-term survival and freedom from repeat aortic valve intervention. Further large cohort studies should be performed to explore the potential benefits of mechanical valve replacement in this age range.

Outcomes of Supra-annular Mechanical Atrioventricular Valve Replacement with Polytetrafluoroethylene Graft in Infants and Children.

Despite improvements in valve repair techniques, conditions in which infants and children need for mechanical valve replacement (MVR) are still present. We analyzed supra-annular MVR outcomes in infants and children with small annulus and compared them with conventional annular MVR outcomes. Data were collected retrospectively from medical records of infants and children (weighing < 20 kg) who underwent atrioventricular valve replacement with mechanical valve in Seoul National University Children's Hospital between December 1984 and January 2019. We identified 8 patients (median age 20 months, median weight 10.2 kg) who underwent supra-annular MVR with polytetrafluoroethylene graft (supra-annular group). The patients were diagnosed with congenital mitral valve malformation (5 patients), complete atrioventricular septal defect (2 patients), and functional single ventricle (1 patient). The implanted mechanical valve size ranged from 16 to 23 mm. Thirty-three patients (median age 40 months, median weight 13 kg) underwent conventional annular MVR (annular group). The survival rate was not significantly different between the supra-annular and annular groups (75.0 vs 78.8%, P = 0.816). In patients with biventricular repair (7 patients with supra-annular MVR and 28 patients with annular MVR), mechanical valve-to-mitral valve annulus size ratio was higher in the supra-annular group than in the annular group (1.24 ± 0.30 vs 0.96 ± 0.22, P = 0.035). No coronary complication or heart block were observed in the supra-annular group. Supra-annular MVR with polytetrafluoroethylene graft may be a feasible surgical option in children with a small annulus when valve repair is unsuccessful.