Bioprosthetic Mitral Valve Research Articles

Effects of Transapical Transcatheter Mitral Valve Implantation.

Purpose: In this study, transapical transcatheter mitral valve-in-valve implantation (TAMVI) was compared with surgical redo mitral valve replacement (SRMVR) in terms of clinical outcomes.Methods: We retrospectively identified patients with degenerated mitral bioprosthesis or failed annuloplasty rings who underwent redo SRMVR or TAMVI at our medical center. Clinical outcomes were based on echocardiography results.Results: We retrospectively identified patients with symptomatic mitral bioprosthetic valve dysfunction (n = 58) and failed annuloplasty rings (n = 14) who underwent redo SRMVR (n = 36) or TAMVI (n = 36). The Society of Thoracic Surgeons Predicted Risk of Mortality scores were higher in the TAMVI group (median: 9.52) than in the SRMVR group (median: 5.59) (p-value = 0.02). TAMVI patients were more severe in New York Heart Association (p-value = 0.04). The total procedure time (skin to skin) and length of stay after procedures were significantly shorter in the TAMVI group, and no significant difference in mortality was noted after adjustment for confounding factors (p-value = 0.11). The overall mean mitral valve pressure gradient was lower in the TAMVI group than in the SRMVR group at 24 months (p < 0.01). Both groups presented a decrease in the severity of mitral and tricuspid regurgitation at 3–24 months.Conclusions: In conclusion, the statistical analysis is still not robust enough to make a claim that TAMVI is an appropriate alternative. The outcome of the patient appears only to be related to the patient's pre-operative STS score. Additional multi-center, longitudinal studies are warranted to adequately assess the effect of TAMVI.

The Characteristics, Long-Term Outcomes, Risk Factors, and Antithrombotic Therapy in Chinese Patients With Atrial Fibrillation and Bioprosthetic Valves.

Introduction: There were few data about the clinical profiles and long-term outcomes in Chinese patients with atrial fibrillation (AF) and bioprosthetic valves.Methods: The retrospective study enrolled 903 patients with bioprosthetic valve replacement at our hospital and discharged with a diagnosis of AF from January 2010 to December 2018.Results: The median age was 65.6 (61.9–69.1) years, and 548 (60.7%) patients were women. During a follow-up period of 3.84 (2.64–5.51) years, 68 (1.8 per 100 person-years) patients died, 81 (2.1 per 100 person-years) patients developed thromboembolism, and 23 (0.6 per 100 person-years) patients experienced major bleeding. The CHA2DS2-VASc score, as a categorical variable (low, moderate, or high risk), predicted the risk of thromboembolism with the C-statistic of 0.6 (95% CI: 0.511–0.689, p = 0.046). The incidence of the CHA2DS2-VASc score increment was 11.6 per 100 person-years, and the annual reclassification rate of stroke risk (from a low or moderate group to a higher group) was 12.7%. The current proportion of oral anticoagulants was 52.3, 59, and 63.2%, respectively, in the low, moderate, and high stroke risk groups. Age (OR: 1.04, 95% CI: 1.01–1.06, p = 0.01), left atrial size (OR: 1.05, 95% CI: 1.03–1.08, p < 0.001), and rheumatic heart disease (OR: 1.49, 95% CI: 1.05–2.10, p = 0.025) were positively associated with the use of oral anticoagulants. The history of chronic kidney disease (OR: 0.20, 95% CI: 0.05–0.76, p = 0.018), prior surgical ablation (OR: 0.33, 95% CI: 0.24–0.47, p < 0.001), and antiplatelet agent use (OR: 0.08, 95% CI: 0.05–0.13, p < 0.001) were inversely related to the use of oral anticoagulants. Higher admission estimated glomerular filtration rate (HR: 0.515, 95% CI: 0.311–0.853, p = 0.01), left ventricular ejection fraction (HR: 0.961, 95% CI: 0.931–0.992, p = 0.014), concomitant surgical ablation (HR: 0.348, 95% CI: 0.171–0.711, p = 0.004), and rheumatic heart disease history (HR: 0.515, 95% CI: 0.311–0.853, p = 0.01) were associated with a lower risk of death. Surgical ablation (HR: 0.263, 95% CI: 0.133–0.519, p < 0.001) and oral anticoagulants (HR: 0.587, 95% CI: 0.375–0.918, p = 0.019) were related to a lower risk of thromboembolism.Conclusion: Chinese patients with AF and bioprosthetic valve(s) were relatively young and had a high prevalence of rheumatic heart disease with few comorbidities. The percentage of mitral bioprosthetic valve replacement was high. The proportion of concomitant surgical ablation or surgical left atrial appendage occlusion or exclusion was relatively low. The thromboembolic events were the major long-term adverse events. The anticoagulation therapy was underused in patients at moderate or high stroke risk. The CHA2DS2-VASc score was verified to be used for predicting stroke risk in this population. The stroke risk dynamically changed; it needed to be reestimated once the risk factor changed.

An uncommon case of bioprosthetic mitral valve thrombosis with subsequent prosthesis dehiscence

Bioprosthetic valve thrombosis (BVT) is uncommon. An 82-year-old gentleman presented following a cardioembolic stroke due to a mitral valve infective endocarditis. The patient underwent bioprosthetic mitral valve replacement. Following discharge, he re-presented with weakness due to a new left-sided stroke and right-sided occipital intracerebral haemorrhage. Both transthoracic and transoesophageal echocardiography revealed BVT on the anterior portion of the prosthesis. Following a multidisciplinary team discussion, it was felt that thrombolytics and anticoagulation would be detrimental. The patient continued to worsen and eventually succumbed to congestive cardiac failure. BVT is uncommon, and patients often present with signs and symptoms of heart failure, shock or embolism. There are no guidelines available on managing BVT in patients with concurrent intracerebral haemorrhage, highlighting the importance of multidisciplinary efforts and patient inclusivity in decision making.

Bioprosthetic interstrut distance subtending the preserved anterior mitral leaflet mitigates left ventricular outflow tract obstruction

BackgroundThe anterior mitral leaflet (AML) contributes to left ventricular (LV) function but is normally excised at the time of a bioprosthetic valve insertion. This study aimed to investigate methods of safely retaining the AML at the time of mitral valve replacement. MethodsFive adult sheep (57 ± 3.8 kg) each underwent 3 insertions of a bioprosthetic mitral valve (asymmetric interstrut sectors) alternating the wide and narrow interstrut distance under the AML. Each insertion was performed on normothermic beating-heart cardiopulmonary bypass, with full retention of the native valve. After each valve insertion, continuous measurements of LV and aortic pressures were recorded with echocardiographic assessment of mitral valve function. If LV outflow tract obstruction (LVOTO) was not seen on the resumption of normal cardiac output, a bolus of adrenaline was given to precipitate it. ResultsThirteen of 15 valve insertions resulted in LVOTO caused by systolic anterior motion (SAM), independent of valve orientation. The wide interstrut distance subtending the AML was associated with a greater requirement for inotropic stress to precipitate an obstruction and was associated with late systolic rather than holosystolic obstruction. ConclusionsThe predisposition to and nature of LVOTO due to SAM were associated with the bioprosthetic valve interstrut distance subtending the fully retained AML and may explain the survival differences in such patients. This model represents an effective method for research into prevention of LVOTO following mitral valve replacement with preservation of the native valve.

Annals for Hospitalists - May 2021.

Annals for Hospitalists - May 2021.

Safety and efficacy of direct oral anticoagulants (DOACs) vs warfarin in patients with concurrent atrial fibrillation and bioprosthetic mitral or aortic valve replacement-a meta analysis

Abstract Funding Acknowledgements Type of funding sources: None. Background- Bioprosthetic valve (BPV) implantation is preferred over mechanical valves for aortic and mitral valve replacement. BPV can have concurrent atrial fibrillation (AF). Primary advantage of BPV is the limited need of anticoagulation (AC) as compared to mechanical valves. However, recommendations for use of AC in BPV are not clear. Purpose We studied direct oral anticoagulants (DOACs) cardiovascular efficacy and safety in BPV as compared to Vitamin K antagonist (VKA, or warfarin). Methods- Electronic databases (PubMed, Embase, Scopus, Cochrane) were searched from inception to November 28th, 2020. Using a generic invariance weighted fixed effects model, Hazard ratios (HRs) and their 95% confidence intervals (CIs) from individual studies were converted to Log HRs and corresponding standard errors, which were then pooled. The primary outcome of interest was stroke or systemic embolisation (SSE), major bleeding and all-cause mortality. Results- A total of four studies with 1386 participants (DOACs n = 723 ; VKA n = 656) were included in analysis. Mean age was 63.7 and 62.4 years in the DOACs and VKA group respectively. Average follow-up period was 1 year and 4 months. DOACs were more efficacious than VKAs in stroke or thromboembolism prevention (HR 0.43, 95%CI 0.20-0.94; p = 0.03). There was no difference in efficacy of DOACs as compared to VKAs in terms of major bleeding (HR 0.60; 95% CI 0.34-1.39; p = 0.09) and all-cause mortality (HR 0.99; 95%CI 0.57-1.7; p = 0.97) (Figure 1). We had no publication bias in our results (Egger’s regression p &amp;gt; 0.05). Conclusion- DOACs have similar mortality, and major bleeding risks as that of VKA at a benefit of higher stroke/thromboembolism prevention in patients with concurrent BPV and AF. Abstract Figure. A)SSE B)Major Bleeding C)Mortality

Role of Cardiac CT in Pre-Procedure Planning for Transcatheter Mitral Valve Replacement

ObjectivesThis study sought to evaluate cardiac computed tomography (CCT) findings and their clinical impact among patients being considered for transcatheter mitral valve replacement (TMVR). BackgroundCCT is used to evaluate whether patients are candidates for TMVR, but limited data exist on the yield of such tests. MethodsPatients referred for pre-procedural CCT for TMVR planning in the context of failing mitral bioprosthetic valves, annuloplasty rings, and severe native valve disease with annular calcification were included in this study. CCT findings were analyzed to evaluate for suitability for TMVR. In the subset of patients who underwent TMVR, echocardiographic and procedural characteristics were recorded. ResultsAmong 80 patients who underwent pre-procedural CCT, the mean age was 71.8 ± 11.4 years, 60% were women, and the mean Society of Thoracic Surgeon score was 9.4 ± 6.7. Most cases were referred for valve-in-native annular calcification planning (n = 43), followed by valve-in-valve (n = 29), and valve-in-ring procedures (n = 8). A total of 51 (64%) patients did not undergo TMVR, 37 of whom had high-risk features identified on CCT. The most common reason for exclusion was related to large annular size, followed by heightened risk of left ventricular outflow tract (LVOT) obstruction. Among 29 patients (36%) who underwent TMVR, the 30-day mortality rate was 17%. Five patients experienced LVOT obstruction, 4 of whom were predicted by CCT. Following TMVR, 5 patients had at least moderate peri-valvular regurgitation. ConclusionsA minority of patients referred for TMVR planning ultimately undergo the procedure. CCT identifies unsuitable anatomy and leads to exclusion in a significant number of cases.

In patients with AF and a bioprosthetic mitral valve, rivaroxaban was noninferior to warfarin for time to clinical events

Guimarães HP, Lopes RD, de Barros E Silva PG, et al. Rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve. N Engl J Med. 2020;383:2117-26. 33196155.

Bioprosthetic versus mechanical mitral valve replacements in patients with rheumatic heart disease.

Rheumatic heart disease (RHD) remains a critical problem in developed countries. Few studies have compared the long-term outcomes of bioprosthetic valves and mechanical valves in patients with RHD who have received mitral valve (MV) replacement. Patients with RHD who received MV replacement with bioprosthetic or mechanical valves were identified between 2000 and 2013 from Taiwan's National Health Insurance Research Database. The primary late outcomes of interest were all-cause mortality and redo MV surgery. Propensity score matching at a 1:1 ratio was performed. We identified 3638 patients with RHD who underwent MV replacement. Among those patients, 1075 (29.5%) and 2563 (70.5%) chose a bioprosthetic valve and mechanical valve, respectively. After matching, 788 patients were assigned to each group. No significant difference in the risk of in-hospital mortality was observed between groups (P=.920). Higher risks of all-cause mortality (10-year actuarial estimates: 50.6% vs 45.5%; hazard ratio, 1.19; 95% confidence interval, 1.01-1.41; P=.040) and MV reoperation (10-year actuarial estimates: 8.9% vs 0.93%; subdistribution hazard ratio, 4.56; 95% confidence interval, 1.71-12.17; P<.01) were observed in the bioprosthetic valve group. Furthermore, the relative mortality benefit associated with mechanical valves was more apparent in younger patients and the beneficial effect persisted until approximately 65years of age. In the patients with RHD who underwent MV replacement, mechanical valves were associated with more favorable long-term outcomes in patients younger than the age of 65years.

Reoperative Mitral Surgery Versus Transcatheter Mitral Valve Replacement: A Systematic Review.

Bioprosthetic mitral structural valve degeneration and failed mitral valve repair (MVr) have traditionally been treated with reoperative mitral valve surgery. Transcatheter mitral valve‐in‐valve (MVIV) and valve‐in‐ring (MVIR) replacement are now feasible, but data comparing these approaches are lacking. We sought to compare the outcomes of (1) reoperative mitral valve replacement (redo‐MVR) and MVIV for structural valve degeneration, and (2) reoperative mitral valve repair (redo‐MVr) or MVR and MVIR for failed MVr. A literature search of PubMed, Embase, and the Cochrane Library was conducted up to July 31, 2020. Thirty‐two studies involving 25 832 patients were included. Redo‐MVR was required in ≈35% of patients after index surgery at 10 years, with 5% to 15% 30‐day mortality. MVIV resulted in >95% procedural success with 30‐day and 1‐year mortality of 0% to 8% and 11% to 16%, respectively. Recognized complications included left ventricular outflow tract obstruction (0%–6%), valve migration (0%–9%), and residual regurgitation (0%–6%). Comparisons of redo‐MVR and MVIV showed no statistically significant differences in mortality (11.3% versus 11.9% at 1 year, P=0.92), albeit higher rates of major bleeding and arrhythmias with redo‐MVR. MVIR resulted in 0% to 34% mortality at 1 year, whereas both redo‐MVr and MVR for failed repairs were performed with minimal mortality and durable long‐term results. MVIV is therefore a viable alternative to redo‐MVR for structural valve degeneration, whereas redo‐MVr or redo‐MVR is preferred for failed MVr given the suboptimal results with MVIR. However, not all patients will be candidates for MVIV/MVIR because anatomical restrictions may preclude transcatheter options from adequately addressing the underlying pathology.

Tip-to-Base LAMPOON for Transcatheter Mitral Valve Replacement With a Protected Mitral Annulus.

The purpose of this study was to evaluate tip-to-base intentional laceration of the anterior mitral leaflet to prevent left ventricular outflow tract obstruction (LAMPOON) in patients undergoing transcatheter mitral valve replacement (TMVR) in annuloplasty rings or surgical mitral valves. LAMPOON is an effective adjunct to TMVR that prevents left ventricular outflow tract obstruction (LVOTO). Laceration is typically performed from the base to the tip of the anterior mitral leaflet. A modified laceration technique from leaflet tip to base may be effective in patients with a prosthesis that protects the aortomitral curtain. This is a multicenter, 21-patient, consecutive retrospective observational cohort. Patients underwent tip-to-base LAMPOON to prevent LVOTO and leaflet overhang, or therapeutically to lacerate a long anterior mitral leaflet risking or causing LVOTO. Outcomes were compared with findings from patients in the LAMPOON investigational device exemption trial with a prior mitral annuloplasty. Twenty-one patients with a annuloplasty or valve prosthesis-protected mitral annulus underwent tip-to-base LAMPOON (19 preventive, 2 rescue). Leaflet laceration was successful in all and successfully prevented or treated LVOTO in all patients. No patients had significant LVOTO upon discharge. There were 2 cases of unintentional aortic valve injury (1 patient underwent emergency transcatheter aortic valve replacement and 1 patient underwent urgent surgical aortic valve replacement). In both cases, the patients had a supra-annular ring annuloplasty, and the retrograde aortic guiding catheter failed to insulate the guidewire lacerating surface from the aortic root. All patients survived to 30days. Compared with classic retrograde LAMPOON, there was a trend toward shorter procedure time. Tip-to-base laceration is a simple, effective, and safe LAMPOON variant applicable to patients with an appropriately positioned mitral annular ring or bioprosthetic valve. Operators should take care to insulate the lacerating surface from adjacent structures.

Outcomes of Surgical Mitral and Aortic Valve Replacements Among Kidney Transplant Candidates: Implications for Valve Selection.

BackgroundLimited literature exists that evaluated outcomes of kidney transplant–eligible patients who are having dialysis and who are undergoing valve replacement. Our main objective in this study was to compare mortality, reoperation, and bleeding episodes between bioprosthetic and mechanical valve procedures among kidney transplant–eligible patients who are having dialysis.Methods and ResultsWe studied 887 and 1925 dialysis patients from the United States Renal Data System, who underwent mitral valve replacement and aortic valve replacement (AVR) after being waitlisted for a kidney transplant (2000–2015), respectively. Time to death, time to reoperation, and time to bleeding requiring hospitalizations were compared separately for AVR and mitral valve replacement. Kaplan–Meier survival curves, Cox proportional hazards model for time to death, accelerated time to event model for time to reoperation, and counting process model for time to recurrent bleeding were used. There were no differences in mortality (hazard ratio [HR], 0.92; 95% CI, 0.77–1.09) or risk of reoperation or risk of significant bleeding events between bioprosthetic and mechanical mitral valve replacement. However, mechanical AVR was associated with a modestly significant less hazard of death (HR, 0.83; 95% CI, 0.74–0.94) compared with bioprosthetic AVR. There were no differences in time to reoperation, or time to significant bleeding events between bioprosthetic and mechanical AVR.ConclusionsFor kidney transplant waitlisted patients who are on dialysis and who are undergoing surgical valve replacement, bioprosthetic and mechanical valves have comparable survival, reoperation rates, and bleeding episodes requiring hospitalizations at both mitral and aortic locations. These findings emphasize that an individualized informed decision is recommended when choosing the type of valve for this special group of patients having dialysis.

Real-time intraoperative co-registration of transesophageal echocardiography with fluoroscopy facilitates transcatheter mitral valve-in-valve implantation in cases of invisible degenerated bioprosthetic valves.

Transcatheter mitral valve-in-valve (TMViV) implantation is an alternative treatment to surgery for high-risk patients with degenerated bioprosthetic mitral valves. Some types of bioprostheses are fluoroscopically translucent, resulting in an 'invisible' target deployment area. In this study, we describe the feasibility and outcomes of this procedure using intraoperative fusion of transoesophageal echocardiography (TEE) and live fluoroscopy to facilitate valve deployment in cases of invisible bioprosthetic valves. We reviewed all TMViV implantations at our centre from July 2014 to July 2019. Patient, procedure and outcome details were compared between those with a visible bioprosthesis (N = 22) to those with an invisible one (N = 12). Intra-operative TEE and live Fluoroscopy co-registration were used for real-time guidance for all invisible targets. All valve implantations were completed successfully in both groups without cardiovascular injury, valve migration or left ventricular outflow-tract obstruction. Technical success was 100% in both groups. One-year survival was 83% [95% confidence interval (CI) 70-96] for the entire cohort, with 79% (95% CI 63-100) survival for the visible group and 92% (95% CI 77-100) for the invisible group. Probability of 1-year survival free from mitral valve reintervention, significant valve dysfunction, stroke or myocardial infraction was 78% (95% CI 63-93) for all patients whereby the probability was 72% (95% CI 54-97) in the visible group and 80% (95% CI 59-100) for the invisible group. The use of intraoperative TEE and live fluoroscopy image fusion facilitates accurate TMViV among patients with a fluoroscopically invisible target-landing zone.

Rivaroxaban, a novel option for patients with atrial fibrillation and a bioprosthetic mitral valve.

Rivaroxaban, a novel option for patients with atrial fibrillation and a bioprosthetic mitral valve.

Bovine pericardial versus porcine stented replacement mitral valves: early hemodynamic performance and clinical results of a randomized comparison of the Perimount and the Mosaic valves.

BackgroundTo compare the hemodynamic and clinical outcomes following mitral valve replacement with the Perimount valve with those of the Mosaic valve.MethodsA total of 145 consecutive patients with rheumatic heart valve disease who underwent single bioprosthetic mitral valve replacement were randomized to receive either the Perimount (n=72) valve or the Mosaic bioprosthesis (n=73). The mean age of patients was 72.1 years (range, 58–89 years) with a sex distribution of 55.2% female and 44.8% male. Patients underwent follow up transthoracic echocardiography at 3 months and 1 year postoperatively. We compared demographics, preoperative clinical data, operative data, hemodynamic profiles, and clinical outcomes.ResultsThe cross-clamp time was similar, with 50.7±15.3 minutes for the Perimount and 50.7±21.8 minutes for the Mosaic bioprosthesis. The total bypass time was also similar, with 91.3±25.7 minutes for the Perimount and 87.8±25.6 minutes for the Mosaic valve. The peak and mean pressure gradients were lower in the Perimount group for all valve sizes and the difference was statistically significant at 1 year. The effective orifice area (EOA) was slightly larger in the Perimount valve (1.98±0.21 vs. 1.89±0.71 cm2, P=0.538) postoperatively, but there was no significant difference at 1 year. There were no differences in preoperative or postoperative left atrium diameter (LAD), left ventricular diastolic diameter (LVDD), left ventricular systolic diameter (LVSD), left ventricular ejection fraction (LVEF), pulmonary artery pressure (PAP). The mortality and major complications rate were similar between the two groups.ConclusionsThe Perimount prostheses is superior to the Mosaic prostheses after mitral valve replacement, achieving statistically significant lower gradients and larger EOA when compared on the basis of manufacturer-labeled valve sizes. Both valves appear to provide satisfactory clinical results.

An Uncommon Case of Bioprosthetic Mitral Valve Thrombosis Complicated by Intracerebral Haemorrhage

An Uncommon Case of Bioprosthetic Mitral Valve Thrombosis Complicated by Intracerebral Haemorrhage

Transcatheter transseptal mitral valve implantation with Edwards SAPIEN 3: the first experience of a single center.

In recent years, there has been a clear trend towards increased mitral bioprosthetic valve surgery in comparison to mechanical prostheses [1]. According to the ESC Guidelines mitral bioprostheses are recommended for patients > 70 years old or those with a life expectancy lower than the presumed durability of the bioprosthesis (class IIa/C). Importantly, the guidelines also recognize the prominence of quality of life after cardiosurgery and focus on patients’ preferences (class Ic), especially if long-term anticoagulation is nonoptimal (class Ic) [2]. Structural deterioration of mitral bioprostheses (structural valve deterioration – SVD) is the main limitation for their use. The average lifespan of a bioprosthetic valve is estimated at 16 years and the reoperation due to SVD affects as many as 75% of patients after a 20-year follow-up [3, 4]. Reoperation is usually associated with high risk of complications and mortality [5, 6]. The alternative option is transcatheter mitral valve implantation (TMVI), especially in patients with high surgical risk. TMVI is indicated in patients with a degenerated mitral bioprosthesis or mitral regurgitation after mitral annuloplasty rings. The results of TMVI have been reported in registries and single-center or case reports [7–10]. Technically, TMVI is feasible via a transapical approach or through venous access and atrial septum puncture. The transapical approach has been dominant in TMVI as it was well tried in transcatheter aortic valve implantation (TAVI) procedures. The transseptal approach is technically more demanding yet due to lesser invasiveness it may lead to superior early and late treatment effects [8]. The latest American registry STS/ACC/TVT reports similar prevalence of TMVI procedures with both approaches [7].

Thrombocytopenia Induced by Giant Atrial Thrombus in Rheumatic Valve Disease- A Case Report

We report a 52-year-old and weight of 79.36 lbs female patient with Thrombocytopenia induced by giant atrial thrombus in rheumatic mitral stenosis. The patient underwent bioprosthetic mitral valve implantation and removal of the giant thrombus. The platelet count progressively increased achieving normal levels one week after surgery.&#x0D; Cardiovasc. j. 2020; 13(1): 95-96

Rivaroxaban in Patients with Atrial Fibrillation and a Bioprosthetic Mitral Valve

BackgroundThe effects of rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve remain uncertain.MethodsIn this randomized trial, we compared rivaroxaban (20 mg once daily) with dose-adjusted warfarin (target international normalized ratio, 2.0 to 3.0) in patients with atrial fibrillation and a bioprosthetic mitral valve. The primary outcome was a composite of death, major cardiovascular events (stroke, transient ischemic attack, systemic embolism, valve thrombosis, or hospitalization for heart failure), or major bleeding at 12 months.ResultsA total of 1005 patients were enrolled at 49 sites in Brazil. A primary-outcome event occurred at a mean of 347.5 days in the rivaroxaban group and 340.1 days in the warfarin group (difference calculated as restricted mean survival time, 7.4 days; 95% confidence interval [CI], −1.4 to 16.3; P<0.001 for noninferiority). Death from cardiovascular causes or thromboembolic events occurred in 17 patients (3.4%) in the rivaroxaban group and in 26 (5.1%) in the warfarin group (hazard ratio, 0.65; 95% CI, 0.35 to 1.20). The incidence of stroke was 0.6% in the rivaroxaban group and 2.4% in the warfarin group (hazard ratio, 0.25; 95% CI, 0.07 to 0.88). Major bleeding occurred in 7 patients (1.4%) in the rivaroxaban group and in 13 (2.6%) in the warfarin group (hazard ratio, 0.54; 95% CI, 0.21 to 1.35). The frequency of other serious adverse events was similar in the two groups.ConclusionsIn patients with atrial fibrillation and a bioprosthetic mitral valve, rivaroxaban was noninferior to warfarin with respect to the mean time until the primary outcome of death, major cardiovascular events, or major bleeding at 12 months. (Funded by PROADI-SUS and Bayer; RIVER ClinicalTrials.gov number, NCT02303795.)

Mechanical testing of glutaraldehyde cross-linked mitral valves. Part one: In vitro mechanical behaviour.

The aim of this study was to perform an initial assessment, in vitro, of the feasibility of using a glutaraldehyde cross-linked porcine mitral valve to retain acute functionality, focusing on assessing mitral regurgitation. Six porcine hearts were tested using an in vitro simulator. Testing was repeated following cross-linking of mitral valves; where cross-linking was achieved by placing them in a glutaraldehyde solution. The simulator enabled systolic pressure on the ventricular side of the valve to be mimicked. Following testing, mitral valve leaflets underwent Scanning Electron Microscopy of the ventricular surface of both the anterior and posterior leaflets (1 cm2 samples). The peak pressure withstood by cross-linked valves was significantly lower than for untreated valves (108 mmHg cf. 128 mmHg for untreated valves; p < 0.05). The peak pressure was typically reached 0.5 s later than for the untreated valve. While both cross-linked and untreated valves exhibited endothelium denudation, the unfixed valve had less endothelial loss. Glutaraldehyde cross-linking of porcine mitral valves may be of potential value in assessing improved bioprosthetic mitral valve replacements. However, a more immobile valve exhibiting endothelial denudation (i.e. sclerosis) was a possible concerns identified following in vitro acute assessment.