Durability of pericardial versus porcine aortic valves

Ten-year Durability, Hemodynamic Performance, and Clinical Outcomes after Transcatheter Aortic Valve Implantation Using a Self-expanding Device

INTRODUCTION

The expansion of transcatheter aortic valve implantation (TAVI) to low-risk and younger patients has increased the relevance of the long-term durability of transcatheter heart valves (THV). The present study aims to assess the 10-year durability, hemodynamic performance, and clinical outcomes after TAVI using the CoreValve system.

METHODS

An analysis from a prospective registry with predefined clinical and echocardiographic follow-up included 302 patients who underwent TAVI with the CoreValve system between 2007 and 2015. Bioprosthetic valve failure (BVF) was defined as any bioprosthetic valve dysfunction-related death, re-intervention, or severe hemodynamic valve deterioration.

RESULTS

At the time of TAVI, the mean age was 80.41 ± 7.01 years, and the Society of Thoracic Surgeons (STS) score was 6.13 ± 5.23%. At latest follow-up (median [IQR]: 5 [2-7] years), cumulative all-cause mortality rates at 3, 5, 7, and 10 years was 23.7%, 40%, 65.8%, and 89.8%, respectively. Mean aortic valve area and transvalvular gradient post-TAVI and at 5, 7, and 10 years were 1.94, 1.87, 1.69, and 1.98 cm2 (p = 0.236) and 8.3, 9.0, 8.2, and 10.1 mmHg (p = 0.796), respectively. Overall, 11 patients had BVF, of whom six had structural valve deterioration (SVD). The 10-year actual and actuarial freedom from BVF was 96.1% and 78.8%, and from SVD was 97.9% and 80.9%, respectively. Three patients developed significant non-SVD due to severe paravalvular leakage, and two patients were diagnosed with infective endocarditis.

CONCLUSION

Using an early-generation self-expanding bioprosthesis, we documented durable hemodynamic performance and low rates of BVF and SVD up to 10 years after TAVI.

Incidence of Prosthesis-Patient Mismatch in Valve-in-Valve with a Supra-Annular Valve

BACKGROUND

Transcatheter aortic valve replacement (TAVR) for a degenerated surgical bioprosthesis (valve-in-valve [ViV]) has become an established procedure. Elevated gradients and patient-prosthesis mismatch (PPM) have previously been reported in mixed TAVR cohorts. We analyzed our single-center experience using the third-generation self-expanding Medtronic Evolut R prosthesis, with an emphasis on the incidence and outcomes of PPM.

METHODS

This is a retrospective analysis of prospectively collected data from our TAVR database. Intraprocedural and intrahospital outcomes are reported.

RESULTS

Eighty-six patients underwent ViV-TAVR with the Evolut R prosthesis. Mean age was 75.5 ± 9.5 years, 64% were males. The mean log EuroScore was 21.6 ± 15.7%. The mean time between initial surgical valve implantation and ViV-TAVR was 8.8 ± 3.2 years. The mean true internal diameter of the implanted surgical valves was 20.9 ± 2.2 mm. Post-AVR, 60% had no PPM, 34% had moderate PPM, and 6% had severe PPM. After ViV-TAVR, 33% had no PPM, 29% had moderate, and 39% had severe PPM. After implantation, the mean transvalvular gradient was reduced significantly from 36.4 ± 15.2 to 15.5 ± 9.1 mm Hg (p < 0.001). No patient had more than mild aortic regurgitation after ViV-TAVR. No conversion to surgery was necessary. Estimated Kaplan-Meier survival at 1 year for all patients was 87.4%. One-year survival showed no significant difference according to post-ViV PPM groups (p = 0.356).

CONCLUSION

ViV-TAVR using a supra-annular valve resulted in low procedural and in-hospital complication rates. However, moderate or severe PPM was common, with no influence on short-term survival. PPM may not be a suitable factor to predict survival after ViV-TAVR.

Long-Term Outcomes of Bovine versus Porcine Mitral Valve Replacement: A Multicenter Analysis

Introduction

Recent national guidelines recommending mitral valve replacement (MVR) for severe secondary mitral regurgitation have resulted in an increased utilization of mitral bioprosthesis. There is a paucity of data on how longitudinal clinical outcomes vary by prosthesis type. We examined long-term survival and risk of reoperation between patients having bovine vs. porcine MVR. Study Design. A retrospective analysis of MVR or MVR + coronary artery bypass graft (CABG) from 2001 to 2017 among seven hospitals reporting to a prospectively maintained clinical registry was conducted. The analytic cohort included 1,284 patients undergoing MVR (801 bovine and 483 porcine). Baseline comorbidities were balanced using 1 : 1 propensity score matching with 432 patients in each group. The primary end point was all-cause mortality. Secondary end points included in-hospital morbidity, 30-day mortality, length of stay, and risk of reoperation.

Results

In the overall cohort, patients receiving porcine valves were more likely to have diabetes (19% bovine vs. 29% porcine; p < 0.001), COPD (20% bovine vs. 27% porcine; p=0.008), dialysis or creatinine >2 mg/dL (4% bovine vs. 7% porcine; p=0.03), and coronary artery disease (65% bovine vs. 77% porcine; p < 0.001). There was no difference in stroke, acute kidney injury, mediastinitis, pneumonia, length of stay, in-hospital morbidity, or 30-day mortality. In the overall cohort, there was a difference in long-term survival (porcine HR 1.17 (95% CI: 1.00-1.37; p=050)). However, there was no difference in reoperation (porcine HR 0.56 (95% CI: 0.23-1.32; p=0.185)). In the propensity-matched cohort, patients were matched on all baseline characteristics. There was no difference in postoperative complications or in-hospital morbidity and 30-day mortality. After 1 : 1 propensity score matching, there was no difference in long-term survival (porcine HR 0.97 (95% CI: 0.81-1.17; p=0.756)) or risk of reoperation (porcine HR 0.54 (95% CI: 0.20-1.47; p=0.225)).

Conclusions

In this multicenter analysis of patients undergoing bioprosthetic MVR, there was no difference in perioperative complications and risk of reoperation of long-term survival after matching.

Excess Reintervention With Mitroflow Prosthesis for Aortic Valve Replacement: Ten-Year Outcomes of a Randomized Trial

BACKGROUND

Current bioprostheses are considered to have improved durability and better hemodynamic performance compared with previous designs, but there are limited comparative data on late outcomes.

METHODS

From 2009 through 2011, 300 adults with severe aortic valve stenosis undergoing aortic valve replacement (AVR) were randomly assigned to receive Edwards Magna, St Jude Epic, or Sorin Mitroflow bioprostheses (n = 100, n = 101, n = 99, respectively). Overall survival was analyzed using Kaplan-Meier and Cox proportional hazards methods, whereas competing risk analysis was used for all time-to-event outcomes. Serial echocardiographic data were fitted with longitudinal models stratified by implant valve size.

RESULTS

During median follow-up of 9.8 years (interquartile range, 8.7-10.2), 10-year survival was 50% for the Magna group, 42% for the Epic group, and 41% for the Mitroflow group (P = .415). Cumulative risk of stroke was 9% at 10 years, and rates were comparable for the three groups. Indexed aortic valve area and mean gradients were similar among the three groups receiving 19 mm and 21 mm valves, but in larger (23 mm or more) prostheses, gradients were lower (P < .001) and indexed aortic valve areas were higher in the Magna group (P < .001). The 10-year risk of endocarditis differed by group (P = .033), with higher incidence in the Mitroflow vs the Magna group (7% vs 0%, P = .019). Late risk of reinterventions in the Mitroflow group was 22%, compared with 0% in the Magna group (P < .001) and 5% in the Epic group (P = .008).

CONCLUSIONS

The Magna valve had the lowest gradients and largest indexed aortic valve area with larger implant sizes. The Mitroflow bioprosthesis is associated with an increased rate of reintervention and possible increased risk of infection compared with Magna and Epic valves.

Transcatheter valve-in-valve or valve-in-ring implantation with a novel balloon-expandable device in patients with bioprosthetic left side heart valves failure: 1-year follow-up from a multicenter experience

BACKGROUND

Transcatheter aortic and mitral valve-in-valve (ViV) or valve-in-ring (ViR) implantation into failed bioprosthetic heart valves (BHVs) or rings represents an appealing, less invasive, treatment option for patients at high surgical risk. Nowadays, few data have been reported on the use of balloon-expandable Myval (Meril Life Science, Vapi, India) transcatheter heart valve (THV) for the treatment of degenerated BHVs or rings. We aimed at evaluating the early and mid-term clinical outcomes of patients with left side heart bioprosthesis deterioration treated with transcatheter ViV/ViR implantation using Myval THV.

METHODS

97 consecutive patients with symptomatic, severe aortic(n=33) and mitral(n=64) BHVs/ring dysfunction underwent transcatheter aortic ViV and mitral ViV/ViR implantation with Myval THV.

RESULTS

Technical success was achieved in 95 (98%) of the patients. Two cases of acute structural trans-catheter mitral ViV/ViR dysfunction requiring a second THV implantation were reported. At 30-day, a significant reduction in prosthetic trans-valvular pressure gradients and increase in valve areas were seen following both aortic and mitral ViV/ViR implantation. Overall survival at 15 months (IQR 8-21) was 92%. Patients undergoing mitral ViV/ViR had a relatively worse survival compared with those undergoing aortic ViV implantation (89% vs. 97% respectively; HR:2.7,CI:0.33-22.7;p=0.34). At longest follow-up available a significant improvement in NYHA functional class I and II was observed in patients with aortic and mitral ViV/ViR implantation(93.8% and 92.1%).

CONCLUSIONS

Despite high surgical risk, transcatheter ViV/ViR implantation for failed left side heart bioprosthesis can be performed safely using Myval THV with a high success rate and low early and mid-term mortality and morbidity.

Hemodynamic and Mid-Term Outcomes for Transcatheter Aortic Valve Replacement in Degenerated Internally Stented Valves

BACKGROUND

Valve-in-valve (ViV) transcatheter aortic valve replacement is indicated in patients undergoing repeat intervention for degenerative aortic valve bioprostheses. Patients with internally stented valves (ie, Mitroflow and Trifecta) are at high risk for coronary artery obstruction during ViV procedures because of valve design, as the leaflets are mounted outside the valve stent.

OBJECTIVES

The aim of this study was to compare the hemodynamic and clinical outcomes of transcatheter aortic valve replacement within internally stented valves (ViV-IS) vs other surgical valves (ViV-OS).

METHODS

Baseline characteristics, hemodynamic parameters, and clinical outcomes of patients who underwent ViV-IS were retrospectively collected and compared with those of patients who underwent ViV-OS.

RESULTS

A total of 250 patients (65% men, median Society of Thoracic Surgeons score 4.4% [IQR: 2.2%-8.4%]) were included. Seventy-one patients (28%) underwent ViV-IS, and 179 (72%) patients underwent ViV-OS. Patients who underwent ViV-OS had better periprocedural hemodynamic status compared with those who underwent ViV-IS (median mean gradient 6 [IQR: 2-13] vs 12 [IQR: 6-16]; P < 0.001). This was not significantly different when both groups were matched on the basis of age, sex, and valve internal diameter size (median mean gradient: 18 [IQR: 13-25] for ViV-OS vs 18 [IQR: 11-24] for ViV-IS; P = 0.36). Coronary protection for potential occlusion was performed more in ViV-IS vs ViV-OS pr (79% vs 6%, respectively; P < 0.001). Patients who underwent ViV-IS had a higher risk for coronary occlusion, requiring stent deployment, compared with those who underwent ViV-OS (54% vs 3%, respectively; P < 0.001. There was no difference in mortality at 3 years between the 2 groups (P = 0.59).

CONCLUSIONS

Patients who underwent ViV-IS had a very high incidence of coronary compromise that can be safely and effectively treated. In the setting of a systematic coronary protection strategy, ViV-OS and ViV-IS provide similar mid-term outcome, and periprocedural hemodynamic status (following adjustment for age, sex, and true internal diameter).

Comparison of modes of failure and clinical outcomes between explanted porcine and bovine pericardial bioprosthetic valves

OBJECTIVE

To compare pathological and hemodynamic modes of failure and operative outcomes between explanted porcine and bovine pericardial bioprosthetic valves.

METHODS

Patients who underwent explantation of their bioprosthetic valves at Toronto General Hospital from 2007 to 2019 were identified. Retrospective chart review was conducted to attain demographic information, operative outcomes, and echocardiography and pathology reports.

RESULTS

A total of 278 patients underwent explantation of their porcine (n=183) or bovine pericardial (n=95) valves. A greater proportion of the porcine group had severe regurgitation, compared to the bovine group (45.3% vs. 19.8%, p<.001). Porcine valves had higher rates of cusp flail (19.4% vs. 3.3%, p<.001). The rates of moderate or worse stenosis were higher among bovine pericardial valves (37.9% vs. 15.8%, p<.001). On pathologic examination, the porcine valves exhibited more cusp tears (67.6% vs. 50.5%, p=.006), while higher incidences of calcification were found in the bovine group (p<.001). Rate of stroke was higher during the explantation procedure of the bovine valves (5.3% vs. 0.5%, p=.040).

CONCLUSIONS

The primary mode of failure was regurgitation in porcine valves due to cusp tears and stenosis in bovine valves due to calcification. Establishing a clear understanding of failure modes based on valve material may improve design and guide valve selection at the time of surgery.

Pericardial Versus Porcine Valves for Surgical Aortic Valve Replacement

Two prototypes of material to constitute surgical bioprosthetic aortic valve (AV) are bovine pericardium and porcine valves. Earlier studies have consistently shown superior hemodynamic profiles in bovine pericardial valves, however, it is not clear whether such superior hemodynamic profiles can be translated into improved clinical outcomes. In patients undergoing isolated bioprosthetic surgical aortic valve replacement (AVR) (636 patients between January 2000 and May 2016), the use of bovine pericardial valves was associated with superior hemodynamic profiles and improved late survival as compared with porcine valves. Freedom from adverse valve-related complication rates were not significantly different between the 2 groups.

Background and Objectives

There still are controversies on which type between bovine pericardial and porcine valves is superior in the setting of aortic valve replacement (AVR). This study aims to compare clinical outcomes of AVR using between pericardial or porcine valves.

Methods

The study involved consecutive 636 patients underwent isolated AVR using stented bioprosthetic valves between January 2000 and May 2016. Of these, pericardial and porcine valves were implanted in 410 (pericardial group) and 226 patients (porcine group), respectively. Clinical outcomes including survival, structural valve deterioration (SVD) and trans-valvular pressure gradient were compared between the groups. To adjust for potential selection bias, inverse probability treatment weighting (IPTW) was conducted.

Results

The mean follow-up duration was 60.1±50.2 months. There were no significant differences in the rates of early mortality (3.1% vs. 3.1%; p=0.81) and SVD (0.3%/patient-year [PY] vs. 0.5%/PY; p=0.33) between groups. After adjustment using IPTW, however, landmark mortality analyses showed a significantly lower late (>8 years) mortality risk in pericardial group over porcine group (hazard ratio [HR], 0.61; 95% confidence interval, [CI] 0.41–0.90; p=0.01) while the risks of SVD were not significantly difference between groups (HR, 0.45; 95% CI, 0.12–1.70; p=0.24). Mean pressure gradient across prosthetic AV was lower in the Pericardial group than the Porcine group at both immediate postoperative point and latest follow-up (p values <0.001).

Conclusions

In patients undergoing bioprosthetic surgical AVR, bovine pericardial valves showed superior results in terms of postoperative hemodynamic profiles and late survival rates over porcine valves.

A novel alternative: transapical transcatheter mitral valve-in-valve implantation using J-Valve for failed bioprosthesis

BACKGROUND

Failed mitral bioprosthesis has conventionally been treated with redo surgical mitral valve replacement (SMVR). Transcatheter mitral valve-in-valve implantation (TM-VIVI) is emerging as an alternative to SMVR in high-risk patients. We report our experience with transapical TM-VIVI using the J-Valve system.

METHODS

From May 2020 to January 2021, 21 patients with a failed mitral bioprosthesis underwent transapical TM-VIVI without concomitant procedures at Guangdong Provincial People's hospital. The mean age was 74.62 years. All patients were heavily symptomatic with severe mitral regurgitation and increased trans-prosthetic gradient. The Society of Thoracic Surgeons predicted risk of mortality (STS PROM) and European System for Cardiac Operative Risk Evaluation II (EuroScore II) scores were used and predicted high mortality (STS PROM, 12.91%±9.94%; EuroScore II, 12.04%±10.5%). All the procedures were performed in a hybrid room.

RESULTS

The success rate was 100% with no conversion to median sternotomy and no intraprocedural death. The mean ventilation time and intensive care unit (ICU) stay were 25±21.44 minutes and 4.14±7.08 days, respectively. No major postoperative complications were observed, except 1 patient suffered pneumonia and required tracheostomy. All patients recovered well. Postoperative echocardiography revealed excellent hemodynamics with no residual mitral regurgitation in 19 patients and mild regurgitation in 2 patients. In a subgroup analysis, no significant differences among procedural and postoperative outcomes were detected in patients with previous aortic-mitral double valve replacement (DVR) compared to other patients.

CONCLUSIONS

Our results demonstrate the safety and feasibility of transapical TM-VIVI using the J-Valve system, even in patients following DVR.

Transoesophageal echocardiography-guided 'primary' valve-in-valve technique in cardiogenic shock: a case report

Background

Transcatheter aortic valve implantation inside a previously implanted bioprosthesis is an alternative treatment for patients with degenerated surgical aortic bioprosthesis (AB) at high surgical risk. Pre-operative computed tomography (CT) scan provides essential information to the procedure planning, although in case of acute presentation it is not always feasible.

Case summary

A 32-year-old man with history of surgical treatment of aortic coarctation and Bio-Bentall procedure was transferred to our department in cardiogenic shock with a suspected diagnosis of acute myocarditis. A transthoracic echocardiogram (TTE) revealed a severely impaired biventricular function and AB degeneration causing severe stenosis. It was decided to undertake an urgent trans-apical valve-in-valve (ViV) procedure. Due to haemodynamic instability, a preoperative CT scan was not performed and transoesophageal echocardiography (TOE) was the main intraprocedural guiding imaging technique. Neither intraprocedural nor periprocedural complications occurred. Serial post-procedural TTE exams showed good functioning of the bioprosthesis and progressive improvement of left ventricular ejection fraction. Patient was discharged from the hospital 8 days after the intervention.

Discussion

A patient with cardiogenic shock due to severe degeneration of the AB was treated with urgent transapical ViV procedure. In this case, where urgent ViV technique was needed, TOE appeared to be a crucial alternative to CT scan and allowed us to perform a successful procedure.

Current Therapeutic Options in Aortic Stenosis

Aortic stenosis is the most common valvular disease requiring valve replacement. Valve replacement therapies have undergone progressive evolution since the 1960s. Over the last 20 years, transcatheter aortic valve replacement has radically transformed the care of aortic stenosis, such that it is now the treatment of choice for many, particularly elderly, patients. This review provides an overview of the pathophysiology, presentation, diagnosis, indications for intervention, and current therapeutic options for aortic stenosis.

A Retrospective Comparison of Hemodynamic and Clinical Outcomes between Two Differently Designed Aortic Bioprostheses for Small Aortic Annuli

The Trifecta valve has externally mounted leaflets; it differs from classic internally mounted valves (e.g., Carpentier-Edwards [C-E]). We evaluated post-implantation hemodynamics and clinical outcomes of these bioprostheses in small aortic annuli. From January 2015 to April 2019, 490 patients who underwent aortic valve replacement (AVR) were reviewed retrospectively. Altogether, 183 patients received 19 or 21 mm diameter C-E (n = 121) or Trifecta (n = 62) prostheses. To minimize confounding variables, we performed propensity-score matching analysis. The mean transvalvular pressure gradient (TVPG) was significantly lower in the Trifecta than in the C-E group at discharge (12.9 ± 4.8 vs. 15.0 ± 5.3 mmHg, p = 0.044). TVPG change over time was not significantly different between groups (p = 0.357). Left ventricular mass index decreased postoperatively (reduction: C-E, 28.1%; Trifecta, 30.1%, p = 0.879). No late mortality, severe patient–prosthesis mismatch, moderate-to-severe paravalvular leakage, structural valve degeneration, or valve thromboses were observed. Freedom from valve-related events at 3 years were similar for C-E (97.9% ± 2.1%) and Trifecta (97.7% ± 2.2%) patients (log-rank p = 0.993). Bioprosthesis design for small annuli significantly affected TVPG immediately after AVR. However, hemodynamics over time and clinical outcomes did not differ between the two designs.

A preclinical trial of perventricular pulmonary valve implantation: Pericardial versus aortic porcine valves mounted on self-expandable stent

Perventricular pulmonary valve implantation (PPVI) of a xenograft valve can be a less invasive technique that avoids cardiopulmonary bypass in patients who require pulmonary valve replacement. We compared the hemodynamics, durability, and histologic changes between two different xenogenic valves (pericardial vs. aortic valve porcine xenografts) implanted into the pulmonary valve position using a PPVI technique and evaluated the safety and efficacy of PPVI as a preclinical study. In 18 sheep, pericardial (group porcine pericardial [PP], n = 9) or aortic valve (group porcine aortic valve [PAV], n = 9) xenogenic porcine valves manufactured as a stented valve were implanted using a PPVI technique. The porcine tissues were decellularized, alpha-galactosidase treated, fixed with glutaraldehyde after space-filler treatment, and detoxified to improve durability. Hemodynamic and immunohistochemical studies were performed after the implantation; radiologic and histologic studies were performed after a terminal procedure. All stented valves were positioned properly after the implantation, and echocardiography and cardiac catheterization demonstrated good hemodynamic state and function of the valves. All the anti-α-Gal IgM and IgG titers were below 0.3 optical density. Computed tomography of extracted valves demonstrated no significant differences in the degree of calcification between the two groups (P = .927). Microscopic findings revealed a minimal amount of calcification and no significant infiltration of macrophage or T-cell in both groups, regardless of the implantation duration. The PPVI is a feasible technique. Both stented valves made of PP and PAV showed no significant differences in hemodynamic profile, midterm durability, and degree of degenerative dystrophic calcification.

Early Basal Cuspal Tear of a Porcine Bioprosthetic Mitral Valve Causing Massive Mitral Regurgitation

Although porcine mitral bioprostheses provide predictably good long-term outcomes, unexpected leaflet tears leading to abrupt haemodynamic changes may occur. Here, we report on a patient who was presented with acute dyspnea due to a cuspal tear of a porcine bioprosthetic mitral valve causing severe mitral regurgitation. Her condition was subsequently complicated by a systemic infection, probably pneumonia, and was successfully managed with an urgent redo-mitral valve replacement.

Possible Link Between the ABO Blood Group of Bioprosthesis Recipients and Specific Types of Structural Degeneration

Background Pigs/bovines share common antigens with humans: α-Gal, present in all pigs/bovines close to the human B-antigen; and AH-histo-blood-group antigen, identical to human AH-antigen and present only in some animals. We investigate the possible impact of patients' ABO blood group on bioprosthesis structural valve degeneration (SVD) through calcification/pannus/tears/perforations for patients ≤60 years at implantation. Methods and Results This was a single-center study (Paris, France) that included all degenerative bioprostheses explanted between 1985 and 1998, mostly porcine bioprostheses (Carpentier-Edwards second/third porcine bioprostheses) and some bovine bioprostheses. For the period 1998 to 2014, only porcine bioprostheses with longevity ≥13 years were included (total follow-up ≥29 years). Except for blood groups, important predictive factors for SVD were prospectively collected (age at implantation/longevity/number/site/sex/SVD types) and analyzed using logistic regression. All variables were available for 500 explanted porcine bioprostheses. By multivariate analyses, the A group was associated with an increased risk of: tears (odds ratio[OR], 1.61; P=0.026); pannus (OR, 1.5; P=0.054), pannus with tears (OR, 1.73; P=0.037), and tendency for lower risk of: calcifications (OR, 0.63; P=0.087) or isolated calcification (OR, 0.67; P=0.17). A-antigen was associated with lower risk of perforations (OR 0.56; P=0.087). B-group patients had an increased risk of: perforations (OR, 1.73; P=0.043); having a pannus that was calcified (OR, 3.0, P=0.025). B-antigen was associated with a propensity for calcifications in general (OR, 1.34; P=0.25). Conclusions Patient's ABO blood group is associated with specific SVD types. We hypothesize that carbohydrate antigens, which may or may not be common to patient and animal bioprosthetic tissue, will determine a patient's specific immunoreactivity with respect to xenograft tissue and thus bioprosthesis outcome in terms of SVD.

[Safety of biological valves for aortic valve replacement: A systematic review and meta-analysis]

OBJECTIVE

To provide a comprehensive and contemporary overview of the long-term safety outcomes after aortic valve replacements (AVR) with conventional biological heart valve (stented or stentless).

METHODS

English databases (Medline, Embase, Web of Science, CENTRAL, and ClinicalTrial.gov) and Chinese databases (CNKI, VIP, WanFang, and SinoMed) were searched systemically from January 1, 2000 to January 26, 2019. Eligible randomized controlled trials, non-randomized clinical trials, cohort studies (retrospective or prospective), and unselected case series were included. Strict screening of the obtained literature was conducted to extract relevant data by two reviewers. Other inclusion criteria were studied reporting on outcomes of AVR with biological valves (stented or stentless), with or without coronary artery bypass grafting (CABG) or valve repair procedure, with mean follow-up length equal to or longer than 5 years. We excluded studies that reported only a specific patient group (e.g., patients with renal failure, or pregnancy), without the report of biological valve type, or with study population size less than 100. The meta-analysis was performed using Stata 14.0 software.

RESULTS

In this study, 53 papers (in total 57 study groups) involving 47 803 patients were included. (1) The all-cause mortality was 6.33/100 patient-years (95%CI: 5.85-6.84). Subgroup analysis showed that the mortality rates of porcine and bovine valve prostheses were 5.69/100 patient-years (95%CI: 5.05-6.41) and 7.29/100 patient-years (95%CI: 6.53-8.13), respectively. The all-cause mortality rates for stented and stentless valve were 6.69/100 patient-years (95%CI: 6.12-7.30) and 5.21/100 patient-years (95%CI: 4.43-6.14), respectively. (2) The incidence rate of thromboembolism was 1.16/100 patient-years (95%CI: 0.96-1.40), the incidence rate of permanent pacemaker (PPM) implantation was 1.08/100 patient-years (95%CI: 0.75-1.54), the incidence rate of stroke was 0.74/100 patient-years (95%CI: 0.51-1.06), the incidence rate of structural valve dysfunction (SVD) was 0.73/100 patient-years (95%CI: 0.59-0.91), the incidence rate of major bleeding was 0.52/100 patient-years (95%CI: 0.41-0.65), the incidence rate of endocarditis was 0.38/100 patient-years (95%CI: 0.33-0.44), and the incidence rate of non-structural valve dysfunction (NSVD) was 0.20/100 patient-years (95%CI: 0.13-0.31). The total reoperation rate for biological aortic valve was 0.77/100 patient-years (95%CI: 0.65-0.91), and the SVD related reoperation rate was 0.46/100 patient-years (95%CI: 0.36-0.58).

CONCLUSION

The all-cause mortality for conventional biological AVR was 6.33/100 patient-years. Thromboembolism, PPM implantation, reoperation, stroke, and SVD were major long term complications.

Postimplant biological aortic prosthesis degeneration: challenges in transcatheter valve implants

Surgical aortic valve replacement (SAVR) is highly effective and can be achieved with relatively low risk in patients with severe aortic stenosis. Bioprostheses have been used most frequently during the past 60 years. However, the function of biological valves usually declines after 10-15 years from implant when structural valve degeneration occurs often mandating a reoperation once valve dysfunction becomes haemodynamically significant. Known for many years by surgeons and cardiologists taking care of patients with SAVR, the issue of postimplant structural valve degeneration has been recently highlighted also in patients with transcatheter aortic valve implant (TAVI). There is growing concern that TAVI valves exhibit structural valve degeneration due to inherent challenges of the deployment mode. The impact on postimplant degeneration of TAVI valves compared to SAVR has still to be understood and defined. Based on the ongoing process of expanding TAVI indications, several potential shortcomings and caveats, learned during the last 60 years of SAVR experience, should be taken into consideration to refine this technique.

How to Avoid Coronary Occlusion During TAVR Valve-in-Valve Procedures

Transcatheter aortic valve-in-valve replacement has been recently reported as a less-invasive alternative to re-do surgery in patients with bioprosthetic valve failure. Although procedural success is achieved in the great majority of patients, this therapy is associated with several potential complications, and coronary occlusion is one of the most feared. This is a rare event, but it is associated with an extremely poor prognosis. In this review, the mechanisms, the identification of patients at high risk, the primary prevention strategies, and treatment of coronary occlusion will be discussed.

Recipients with blood group A associated with longer survival rates in cardiac valvular bioprostheses

Background

Pigs/bovines share with humans some of the antigens present on cardiac valves. Two such antigens are: the major xenogenic Ag, “Gal” present in all pig/bovine very close to human B-antigen of ABO-blood-group system; the minor Ag, pig histo-blood-group AH-antigen identical to human AH-antigen and present by some animals. We hypothesize that these antigens may modify the immunogenicity of the bioprosthesis and also its longevity. ABO distribution may vary between patients with low (<6 years) and high (≥15 years) bioprostheses longevity.

Methods

Single-centre registry study (Paris, France) including all degenerative porcine bioprostheses (mostly Carpentier-Edwards 2nd/3rd generation heart valves) explanted between 1985 and 1998 and some bovine bioprostheses. For period 1998–2014, all porcine bioprostheses with longevity ≥13 years (follow-up ≥29 years). Important predictive factors for bioprosthesis longevity: number, site of implantation, age were collected. Blood group and other variables were entered into an ordinal logistic regression analysis model predicting valve longevity, categorized as low (<6 years), medium (6–14.9 years), and high (≥15 years).

Findings

Longevity and ABO-blood group were obtained for 483 explanted porcine bioprostheses. Mean longevity was 10.2 ± 3.9 years [0–28] and significantly higher for A-patients than others (P = 0.009). Using multivariate analysis, group A was a strong predictive factor of longevity (OR 2.09; P < 0.001). For the 64 explanted bovine bioprosthesis with low/medium longevity, the association, with A-group was even more significant.

Interpretation

Patients of A-group but not B have a higher longevity of their bioprostheses. Future graft-host phenotyping and matching may give rise to a new generation of long-lasting bioprosthesis for implantation in humans, especially for the younger population.

Fund

None.

Bioprosthetic structural valve deterioration: How do TAVR and SAVR prostheses compare?

BACKGROUND

The durability of TAVR prostheses has come under major scrutiny since the move towards lower risk patients. We sought to compare the rate of structural valve deterioration (SVD) over time between transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR).

METHODS

We included all TAVR and SAVR patients (age ≥ 75 years) that were performed in our centre from 2005 until 2015. Applying the internationally "agreed on" definitions of SVD, we surveyed all available serial echocardiographic follow-ups.

RESULTS

We included 269 TAVR and 174 SAVR cases. Post-intervention, TAVR patients had lower mean and peak gradients but higher rate of mild aortic regurgitation. SAVR patients had longer follow-up (in months, SAVR: 53 (30, 85) Vs TAVR: 33.4 (23, 52)). SVD as per Valve Academic Research Consortium-2 (VARC-2) was similar between the two groups (TAVR 28% Vs SAVR 31%; P = 0.593) but moderate haemodynamic SVD (European Association of Percutaneous Cardiovascular Intervention (EAPCI) criteria) was more common among SAVR cases (TAVR 11.5% Vs SAVR 20.7%; P = 0.007). Using Kaplan-Meier estimates, the rate of SVD over time was not different between the two groups as per VARC-2 criteria but different when moderate haemodynamic SVD criteria were applied (Log Rank P = 0.022) in favour of TAVR. The mean gradient rose steadily over time but more so post-SAVR (β = 0.52 ± 0.24 in comparison to TAVR at every given time point; P = 0.032).

CONCLUSION

Structural valve deterioration is common on long-term follow-up post-TAVR. The rate is similar to post-SAVR cases according to VARC-2 criteria but less according to the moderate haemodynamic SVD criteria.

Bioprosthetic aortic valve replacement in elderly patients: Meta-analysis and microsimulation

OBJECTIVE

To support decision-making in aortic valve replacement (AVR) in elderly patients, we provide a comprehensive overview of outcome after AVR with bioprostheses.

METHODS

A systematic review was conducted of studies reporting clinical outcome after AVR with bioprostheses in elderly patients (mean age ≥70 years; minimum age ≥65 years) published between January 1, 2000, to September 1, 2016. Reported event rates and time-to-event data were pooled and entered into a microsimulation model to calculate life expectancy and lifetime event risks.

RESULTS

Forty-two studies reporting on 34 patient cohorts were included, encompassing a total of 12,842 patients with 55,437 patient-years of follow-up (pooled mean follow-up 5.0 ± 3.3 years). Pooled mean age was 76.5 ± 5.5 years. Pooled early mortality risk was 5.42% (95% confidence interval [CI], 4.49-6.55), thromboembolism rate was 1.83%/year (95% CI, 1.28-3.61), and bleeding rate was 0.75%/year (95% CI, 0.50-1.11). Structural valve deterioration (SVD) was based on pooled time to SVD data (Gompertz; shape: 0.124, rate: 0.003). For a 75-year-old patient, this translated to an estimated life expectancy of 9.8 years (general population: 10.2 years) and lifetime risks of bleeding of 7%, thromboembolism of 17%, and reintervention of 9%.

CONCLUSIONS

The low risks of SVD and reintervention support the use of bioprostheses in elderly patients in need of AVR. The estimated life expectancy after AVR was comparable with the general population. The results of this study inform patients and clinicians about the expected outcomes after bioprosthetic AVR and thereby support treatment decision-making. Furthermore, our results can be used as a benchmark for long-term outcomes after transcatheter aortic valve implantation in patients who were eligible for surgery and other (future) alternative treatments (eg, tissue-engineered heart valves).

In vitro evaluation of implantation depth in valve-in-valve using different transcatheter heart valves

AIMS

Transcatheter heart valve (THV) implantation in failed bioprosthetic valves (valve-in-valve [ViV]) offers an alternative therapy for high-risk patients. Elevated post-procedural gradients are a significant limitation of aortic ViV. Our objective was to assess the relationship between depth of implantation and haemodynamics.

METHODS AND RESULTS

Commercially available THVs used for ViV were included in the analysis (CoreValve Evolut, SAPIEN XT and the Portico valve). THVs were implanted in small surgical valves (label size 19 mm) to simulate boundary conditions. Custom-mounted pulse duplicators registered relevant haemodynamic parameters. Twenty-eight experiments were performed (13 CVE, 5 SXT and 10 Portico). Ranges of depth of implantation were: CVE: -1.2 mm to 15.7 mm; SXT: -2.2 mm to 7.5 mm; Portico: 1.4 mm to 12.1 mm. Polynomial regression established a relationship between depth of implantation and valvular mean gradients (CVE: p<0.001; SXT: p=0.01; Portico: p=0.002), as well as with EOA (CVE: p<0.001; SXT: p=0.02; Portico valve: p=0.003). In addition, leaflet coaptation was better in the high implantation experiments for all valves.

CONCLUSIONS

The current comprehensive bench testing assessment demonstrates the importance of high device position for the attainment of optimal haemodynamics during aortic ViV procedures.

Microstructural alterations owing to handling of bovine pericardium to manufacture bioprosthetic heart valves: A potential risk for cusp dehiscence

INTRODUCTION

Cross-linking and anti-calcification of prosthetic heart valves have been continuously improved to prevent degeneration and calcification. However, non-calcific structural deteriorations such as cuspal dehiscences along the stent still require further analysis.

MATERIAL AND METHOD

Based upon the previous analysis of an explanted valve after 7 years, a fresh commercial aortic valve was embedded in poly(methyl methacrylate) (PMMA) and cut into slices to ensure the detailed observation of the assembly and material structures. A pericardial patch embossed to provide the adequate shape of the cusps was investigated after paraffin embedding and appropriate staining. The microstructural damages that occurred during manufacturing process were identified and evaluated by light microscopy, polarized microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

RESULTS

The wavy collagen bundles, the key structure of the pericardium patch, were damaged to a great extent at suture sites along the stent and in the compressed areas around the stent post. The fixation of the embossed pericardium patch along the plots of the stent aggravated the microstructural modifications. The damages mainly appeared as the elimination of collagen bundle waviness and delamination between the bundles.

CONCLUSION

Considering the modes of failure of the explant, the damages to the collagen bundles may identify the vulnerable sites that play an important role in the cusp dehiscence of heart valve implants. Such information is important to the manufacturers. Recommendations to prevent in vivo cusp dehiscence can therefore be formulated.

Decellularization of human donor aortic and pulmonary valved conduits using low concentration sodium dodecyl sulfate

The clinical use of decellularized cardiac valve allografts is increasing. Long‐term data will be required to determine whether they outperform conventional cryopreserved allografts. Valves decellularized using different processes may show varied long‐term outcomes. It is therefore important to understand the effects of specific decellularization technologies on the characteristics of donor heart valves. Human cryopreserved aortic and pulmonary valved conduits were decellularized using hypotonic buffer, 0.1% (w/v) sodium dodecyl sulfate and nuclease digestion. The decellularized tissues were compared to cellular cryopreserved valve tissues using histology, immunohistochemistry, quantitation of total deoxyribose nucleic acid, collagen and glycosaminoglycan content, in vitro cytotoxicity assays, uniaxial tensile testing and subcutaneous implantation in mice. The decellularized tissues showed no histological evidence of cells or cell remnants and >97% deoxyribose nucleic acid removal in all regions (arterial wall, muscle, leaflet and junction). The decellularized tissues retained collagen IV and von Willebrand factor staining with some loss of fibronectin, laminin and chondroitin sulfate staining. There was an absence of major histocompatibility complex Class I staining in decellularized pulmonary valve tissues, with only residual staining in isolated areas of decellularized aortic valve tissues. The collagen content of the tissues was not decreased following decellularization however the glycosaminoglycan content was reduced. Only moderate changes in the maximum load to failure of the tissues were recorded postdecellularization. The decellularized tissues were noncytotoxic in vitro, and were biocompatible in vivo in a mouse subcutaneous implant model. The decellularization process will now be translated into a good manufacturing practices‐compatible process for donor cryopreserved valves with a view to future clinical use. Copyright © 2016 The Authors Tissue Engineering and Regenerative Medicine published by John Wiley & Sons, Ltd.

Transcatheter Aortic Valve Replacement: State of the Art and Future Directions

Transcatheter aortic valve replacement (TAVR) is a transformational and rapidly evolving treatment for patients with aortic stenosis who require valve replacement. Novel technological advancements have made this percutaneous minimally invasive therapy a first-line treatment for many patients at extreme risk for conventional cardiac surgery. New devices and improvements in existing devices have reduced procedural complications, and scientific trials are investigating the role of TAVR in lower-risk aortic stenosis populations, in patients with aortic regurgitation, and in patients with bicuspid aortic valve disease. Finally, there is intense interest in identifying patients in whom the risk-benefit ratio of TAVR is not favorable and should not be performed.

Transcatheter Replacement of Failed Bioprosthetic Valves

Background—

Transcatheter valve implantation inside failed bioprosthetic surgical valves (valve-in-valve [ViV]) may offer an advantage over reoperation. Supra-annular transcatheter valve position may be advantageous in achieving better hemodynamics after ViV. Our objective was to define targets for implantation that would improve hemodynamics after ViV.

Methods and Results—

Cases from the Valve-in-Valve International Data (VIVID) registry were analyzed using centralized core laboratory assessment blinded to clinical events. Multivariate analysis was performed to identify independent predictors of elevated postprocedural gradients (mean ≥20 mm Hg). Optimal implantation depths were defined by receiver operating characteristic curve. A total of 292 consecutive patients (age, 78.9±8.7 years; 60.3% male; 157 CoreValve Evolut and 135 Sapien XT) were evaluated. High implantation was associated with significantly lower rates of elevated gradients in comparison with low implantation (CoreValve Evolut, 15% versus 34.2%; P =0.03 and Sapien XT, 18.5% versus 43.5%; P =0.03, respectively). Optimal implantation depths were defined: CoreValve Evolut, 0 to 5 mm; Sapien XT, 0 to 2 mm (0–10% frame height); sensitivities, 91.3% and 88.5%, respectively. The strongest independent correlate for elevated gradients after ViV was device position (high: odds ratio, 0.22; confidence interval, 0.1–0.52; P =0.001), in addition to type of device used (CoreValve Evolut: odds ratio, 0.5; confidence interval, 0.28–0.88; P =0.02) and surgical valve mechanism of failure (stenosis/mixed baseline failure: odds ratio, 3.12; confidence interval, 1.51–6.45; P =0.002).

Conclusions—

High implantation inside failed bioprosthetic valves is a strong independent correlate of lower postprocedural gradients in both self- and balloon-expandable transcatheter valves. These clinical evaluations support specific implantation targets to optimize hemodynamics after ViV.

Durability after aortic valve replacement with the Mitroflow versus the Perimount pericardial bioprosthesis: a single-centre experience in 2393 patients

OBJECTIVES

This study compares the durability and risk of reoperation in patients undergoing aortic valve replacement (AVR) with either a Mitroflow or a Carpentier-Edwards (CE) pericardial bioprosthesis. Since AVR with bioprosthetic valves has increased progressively in recent years as compared to mechanical valves, especially in patients aged 60-70 years, there has been renewed interest in the long-term durability of current pericardial bioprostheses.

METHODS

We compared 440 AVR with Mitroflow valves with 1953 AVR with CE pericardial valves implanted from 1999 to 2014 with regard to reoperation, reoperation for structural valve deterioration (SVD) and all-cause mortality.

RESULTS

Ten-year freedom from explant of any cause was higher for CE Perimount (98 ± 0.7%) than for Mitroflow (95 ± 1.4%, P < 0.01). Reasons for explant for CE Perimount were SVD (n = 2), endocarditis (n = 8) and paraprosthetic leak (n = 10). The reasons for explant for Mitroflow were SVD (n = 11), endocarditis (n = 3) SVD and pericarditis (n = 1) and paraprosthetic leak (n = 2). Ten-year freedom from explant due to SVD was higher for CE Perimount (100%) than for Mitroflow (96%) (P < 0.01). In small aortic annuli (bioprosthesis size 19-21 mm), freedom from SVD at 10 years for CE Perimount and Mitroflow was 100 versus 96%, respectively. By multivariate analysis, it was found that bioprosthesis size was not a risk factor for SVD. The choice of valve type could not be demonstrated to influence long-term survival.

CONCLUSIONS

The Mitroflow pericardial bioprosthesis provides less than optimal mid- and long-term durability compared with the CE Perimount pericardial valve, especially for small aortic diameter implants (19 and 21 mm). This study hereby confirms the existence of a real risk of valvular deterioration of the Mitroflow valve that might compromise the prognosis of the patients.

EFFICACY OF CARPENTIER-EDWARDS PERICARDIAL PROSTHESES: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objectives: The Carpentier-Edwards pericardial (CEP) prostheses are the type of bioprostheses most used worldwide. Although they were designed to minimize the rate of valve deterioration and reoperation, their clinical superiority over other prostheses models still lacks confirmation. The objective of this study was to evaluate its effectiveness.

Methods: We performed a systematic review and meta-analysis in the PubMed, Embase, Cochrane, and Lilacs databases. Operative mortality, overall mortality and reoperation rates after heart valve surgery were compared between the use of CEP and other cardiac prostheses. Two independent reviewers screened studies for inclusion and extracted the data. Disagreements were resolved by consensus. The GRADE criterion was used to assess the evidence quality.

Results: A total of twenty-eight studies were selected, including 19,615 individuals. The studies presented a high heterogeneity and low quality of evidence what limited the reliability of the results. The pooled data from the selected studies did not demonstrate significant differences between CEP and porcine, pericardial or stentless prostheses regarding operative mortality, overall mortality and reoperation rates. However, the pooled data from 3 observational trials pointed out a higher risk for reoperation after valve replacement using CEP prostheses against mechanical prostheses (OR 4.92 [95 percent confidence interval 2.43–9.96]).

Conclusions: The current data present in the literature still does not support a clinical advantage for the use of CEP prostheses over other bioprostheses. The quality of the studies in the literature is limited and further studies are needed to address if CEP prostheses will have a clinical advantage over other prostheses.

Long-term durability of pericardial valves in the aortic position in younger patients: when does reoperation become necessary?

BACKGROUND

We sought to assess the long-term durability of pericardial valves in patients at age <65 years undergoing aortic valve replacement (AVR), and to determine the timing of redo operations due to structural valve deterioration (SVD).

METHODS

From 1986 to 2001, a total of 574 adult patients underwent AVR with pericardial valves in nine hospitals in Japan. Of these, 53 patients were at age <65 years (group Y). These patients were compared with those of age ≥ 65 (group O, n = 521).

RESULTS

The mean follow-up duration was 9.5 years in group Y and 8.1 years in group O. Freedom from reoperation due to SVD was 100% at five years, 90.8% at 10 years, and 47.2% at 15 years in group Y, and 99.3% at five years, 97.4% at 10 years, and 94.4% at 15 years in group O (log-rank test, p < 0.01). In those who required redo AVR in group Y (n = 12), the mean time from initial operation to reoperation was 12.1 years. The reoperation-free survival curve started to decline after eight years postoperation in group Y.

CONCLUSIONS

Redo AVR started to become necessary eight years after surgery in the patients who underwent AVR with pericardial valve at age <65 years. In addition, approximately half of those patients required reoperation due to SVD by 15 years postoperatively.

Comparison of the early haemodynamics of stented pericardial and porcine aortic valves

Data comparing the haemodynamic performance of stented pericardial and porcine aortic valves are conflicting. Hence, we performed a systematic review and meta-analysis comparing the early haemodynamic parameters of stented pericardial and porcine valves in patients undergoing isolated aortic valve replacement. Medline, EMBASE and Web of Science were queried for English language original publications from 2000 to 2013. Studies comparing porcine (PoV) and pericardial (PeV) with regard to their haemodynamic parameters were included in this review. Continuous data were pooled using the mean difference (MD) or the standardized mean difference (SMD). A random-effect inverse weighted analysis was conducted; a P-value<0.05 is considered statistically significant. Results are presented with 95% confidence intervals. Thirteen studies (1265 PeV patients and 871 PoV patients) were included in this analysis. The pooled transvalvular mean gradient was lower for PeV [MD -4.6 (-6.45 to -2.77) mmHg; P<0.01]. Limiting this analysis to small valves (19 and 21 mm; eight studies; 714 patients) revealed that the PeV gradients were significantly lower [MD -4.5 (-5.7 to -3.2); P=0.001]. The corresponding effective orifice area of PeV was significantly larger than PoV [SMD 0.42 (0.15-0.69); P<0.01]. A sensitivity analysis comprising only randomized controlled trials did not significantly alter results. When compared with porcine valves, stented pericardial aortic valves have lower mean transvalvular gradients early after implant. Even pericardial valves in smaller sizes (19 and 21 mm) have a better haemodynamic profile when compared with their counterparts.

Comparable long-term results for porcine and pericardial prostheses after isolated aortic valve replacement

OBJECTIVES

Outcome of aortic valve replacement may be influenced by the choice of bioprosthesis. Pericardial heart valves are described to have a favourable haemodynamic profile compared with porcine valves, although the clinical notability of this finding is still controversially debated. Herein, we compared the long-term results of two commonly implanted bioprosthesis at a single centre.

METHODS

All consecutive patients undergoing isolated aortic valve replacement with either a Carpentier-Edwards Magna pericardial prosthesis or a Medtronic Mosaic porcine prosthesis between 2002 and 2008 were analysed regarding preoperative characteristics, short- and long-term survival, valve-related complications and echocardiographic findings.

RESULTS

The Medtronic Mosaic was implanted in 163 patients and the Carpentier-Edwards Magna in 295 patients. The sizes of implanted valves were 22.4 ± 1.5 mm for the Mosaic and 21.8 ± 1.8 mm for the Magna (P = 0.001). The long-term survival rate was 76 and 56% after 5 and 10 years for the Medtronic Mosaic, which was comparable with the Carpentier-Edwards Magna (77 and 57%; P = 0.92). Overall long-term survival was comparable with an age- and sex-matched Austrian general population for both groups. Valve-related adverse events were similar between groups. The postoperative mean transvalvular gradient was significantly increased in the Mosaic group (24 ± 9 mmHg vs 17 ± 7 mmHg; P < 0.001).

CONCLUSIONS

Both types of aortic bioprostheses offer excellent results after isolated aortic valve replacement. Despite relevant differences in gradients, long-term survival was comparable with the expected normal survival for both bioprostheses. Patients with a porcine heart valve had a higher postoperative transvalvular gradient.

Regenerative potential of low-concentration SDS-decellularized porcine aortic valved conduits in vivo

The aims of this study were to determine the functional biocompatibility of low-concentration SDS-decellularized porcine aortic roots in vivo. A previously developed process was modified for 9- and 15-mm-diameter aortic roots to facilitate implantation into the porcine abdominal aorta (n=3) and juvenile sheep right ventricular outflow tract (n=7), respectively. Native allogeneic aortic roots were used as controls. Acellular porcine roots explanted from pigs at weeks were largely repopulated with stromal cells of appropriate phenotype, and there was evidence that macrophages were involved in the regenerative process. Native allogeneic roots were subject to a classic allograft rejection response. Acellular porcine roots explanted from sheep at 6 months showed evidence of appropriate cellular repopulation, again with evidence of a role for macrophages in the regenerative process. There was some degree of calcification of two of the explanted acellular roots, likely due to incomplete removal of DNA before implantation. Native allogeneic ovine roots were subject to a classic allograft rejection response involving T cells, which resulted in overtly calcified and damaged tissues. The study highlighted (1) the importance of removal of DNA from acellular porcine valved roots to avoid calcification and (2) a role for macrophages in the regeneration of low-concentration SDS-decellularized aortic roots, as has been reported for other acellular biological extracellular matrix scaffolds.

Clinical evaluation of new heart valve prostheses: update of objective performance criteria

This article summarizes the long-term clinical results of the Food and Drug Administration-approved heart valves, provides current updates to the objective performance criteria (OPC) used to evaluate new heart valve prostheses, and documents the steps that the International Organization for Standardization Committee used to arrive at the updated OPC. Data were extracted from 19 Food and Drug Administration summaries of safety and effectiveness data reports (31 series) and 56 literature articles (85 series) published from 1999 to 2012. The OPC were calculated for five valve-related complications by valve type (mechanical and bioprosthetic) and valve position (aortic and mitral).