Aortic Valve Replacement With the Medtronic Mosaic Bioprosthesis: A 13-Year Follow-Up

Recent Advances in the Modification and Improvement of Bioprosthetic Heart Valves

Valvular heart disease (VHD) has become a burden and a growing public health problem in humans, causing significant morbidity and mortality worldwide. An increasing number of patients with severe VHD need to undergo heart valve replacement surgery, and artificial heart valves are in high demand. However, allogeneic valves from donors are lacking and cannot meet clinical practice needs. A mechanical heart valve can activate the coagulation pathway after contact with blood after implantation in the cardiovascular system, leading to thrombosis. Therefore, bioprosthetic heart valves (BHVs) are still a promising way to solve this problem. However, there are still challenges in the use of BHVs. For example, their longevity is still unsatisfactory due to the defects, such as thrombosis, structural valve degeneration, calcification, insufficient re-endothelialization, and the inflammatory response. Therefore, strategies and methods are needed to effectively improve the biocompatibility and longevity of BHVs. This review describes the recent research advances in BHVs and strategies to improve their biocompatibility and longevity.

The Longest Known Survival of a Patient With Bioprosthetic Aortic Valve Replacement: A 42-Year Follow-Up

Aortic valve replacement (AVR) is a frequently performed procedure for treating aortic valvulopathy. AVR involves replacing the damaged aortic valve with either a mechanical or a bioprosthetic valve. While many factors are involved when selecting between the two options, age and patient preference are the deciding factors at this point. Mechanical valves demonstrate long-standing durability that overlaps with the accompanied bleeding risk due to lifetime anticoagulant therapy, making them a more favorable choice for younger patients. Bioprosthetic valves are preferred for older patients as they show a reduced risk of thrombogenicity. However, bioprosthetic valves have a higher incidence of structural valve degeneration (SVD) than mechanical valves. Our case report focuses on a 76-year-old patient who had undergone an AVR with a bioprosthetic valve at the age of 33, which has still not demonstrated any valve deterioration. As the longest known case of bioprosthetic durability, this patient provides useful data for designing bioprosthetic valves more resistant to structural degeneration and thereby better suited to younger patients or those at higher risk of bleeding.

Antithrombotic therapy and bleeding events after aortic valve replacement with a novel bioprosthesis

OBJECTIVE

Several recent-generation surgical tissue valves have been found to have bleeding rates exceeding rates recommended by regulatory bodies. We explored bleeding events using data from the Pericardial Surgical Aortic Valve Replacement (PERIGON) Pivotal Trial for the Avalus valve (Medtronic, Minneapolis, Minn) to examine whether this end point remains relevant for the evaluation of bioprostheses.

METHODS

Patients (n = 1115) underwent aortic valve replacement. Bleeding and thromboembolic event episodes in patients within 3 years postimplant were analyzed for frequency, timing, and severity, focusing on patients taking antiplatelet/anticoagulant medications at the time of the event. Clinical and hemodynamic outcomes are also reported.

RESULTS

At 3 years, the Kaplan-Meier cumulative probability estimate of all-cause death was 7.2% (cardiac, 3.6%; valve-related, 1.1%). The Kaplan-Meier cumulative probability estimates of all and major hemorrhage were 8.7% and 5.2%, respectively. Ninety-nine bleeding events occurred in 86 patients: most occurred >30 days postsurgery. Among the 51 late major bleeds, in 5 cases the patients were taking anticoagulant/antiplatelet medication for prophylaxis after surgical aortic valve replacement at the time of the event, whereas the remaining patients were taking medications for other reasons. Age (hazard ratio, 1.035; 95% confidence interval, 1.004-1.068), peripheral vascular disease (hazard ratio, 2.135; 95% confidence interval, 1.106-4.122), renal dysfunction (hazard ratio, 1.920; 95% confidence interval, 1.055-3.494), and antithrombotic medication use at the time of the event (hazard ratio, 1.417; 95% confidence interval, 1.048-1.915) were associated with late bleeds (major and minor).

CONCLUSIONS

Overall clinical outcomes demonstrated low mortality and few complications except for major bleeding. Most bleeding events occurred >30 days after surgery and in patients taking antiplatelet and/or anticoagulation for indications other than postimplant prophylaxis.

Hemodynamic Performance and Outcomes of Mosaic Valve for Aortic Stenosis with Decreased Left Ventricular Function: Results from J-MOVE Study

We evaluated impact of a small-sized Mosaic porcine bioprosthesis on hemodynamic performance and outcomes in patients with aortic stenosis (AS) and low left ventricular ejection fraction (LVEF) in a Japan multicenter cohort. Of 1,202 patients enrolled, 105 (8.7%) who had LVEF < 50% and AS underwent aortic valve replacement (AVR). Fifty-two patients received Mosaic porcine bioprosthesis ≤ 21 mm (S-AVR), and 53 received a bioprosthesis ≥ 23 mm (L-AVR). The median follow-up period was 3.1 [1.2, 5.1] years. At 5 years, LVEF significantly improved from median 41.2 [33.8, 45.9]% to 64.2 [49.8, 72.5]% in S-AVR (p < 0.001) and from median 43.2 [37.3, 46.8]% to 61.2 [47.2, 68.0]% in L-AVR (p < 0.001). The left ventricular mass index significantly decreased from median 158.4 [122.2, 194.9] to 110.0 [83.6, 129.4] gm/m in S-AVR (p < 0.001) and from median 169.8 [132.2, 203.6] to 109.6 [101.8, 132.4] gm/m in L-AVR (p < 0.001). There were no significant differences between S-AVR and L-AVR groups regarding freedom from cardiac death (93.1 ± 3.9% vs. 96.2 ± 3.8%; p = 0.119) and valve-related death (97.6 ± 2.4% vs. 100.0 ± 0.0%; p = 0.953). Clinical outcomes and improved hemodynamic performance were similar in both groups.

Real Structural Valve Deterioration of the Mitroflow Aortic Prosthesis: Competing Risk Analysis

INTRODUCTION AND OBJECTIVES

The Mitroflow aortic prosthesis is a bovine pericardial bioprosthesis specially designed to increase the valve area in relation to its size. There is controversy regarding the pattern of structural valve deterioration (SVD). Our aim was to determine the cumulative incidence of SVD, risk factors influencing its occurrence, and its impact on mortality.

METHODS

A total of 1028 patients were clinically and echocardiographically followed up. Because the study population was elderly and had heart disease, we used a competing risk analysis.

RESULTS

The percentage of patients with SVD at 5 years was 4.22% (95%CI, 2.96-5.81) and was 15.77% at 8 years (95%CI, 12.46-19.43). The incidence was higher for small valves (19mm and 21mm) reaching 6.43% at 5 years (95%CI, 4.48-8.84) and 20.06% at 8 years (95%CI, 15.53-25.01). Severe patient-prosthesis mismatch (PPM) influenced the incidence of SVD (_sHR, 3.53; 95%CI, 2.20-5.66; P < .001) but moderate PPM had no impact. The most powerful predictor of mortality was the presence of SVD (HR, 4.59; 95%CI, 2.91-7.22; P < .001).

CONCLUSIONS

This study used a definition based on the increase in the transprosthetic gradient and found a higher incidence of SVD of the Mitroflow prosthesis than that reported by other series, especially for sizes 19mm and 21mm and in patients with severe PPM. The incidence of SVD increased exponentially from the fifth year after implantation and its occurrence led to a 4.5-fold increase in the risk of death.

Mid- to Long-term Clinical Outcomes of Hancock II Bioprosthesis in Chinese Population

Background:

Compared to the Western countries, Chinese patients present a special primary disease spectrum, diverse valvular pathogenesis, and different postoperational anticoagulation strategy. This research aimed to evaluate the mid- to long-term clinical performance of Hancock II bioprosthesis in the Chinese population.

Methods:

This study retrospectively reviewed all patients who received surgical treatments with at least one Hancock II bioprosthesis implantation from January 2004 to December 2013 at a single center in China. Totally 647 patients were included in the clinical evaluation, and 629 patients were successfully discharge, among whom 605 patients were completely followed-up. The follow-up rate was 96.2%. The mean and median follow-up time was 62.0 ± 59.0 and 56.0 months, respectively. Postoperative outcomes of survival rates, reoperations and valve related morbidities were assessed. Continuous and categorical variables were compared using the t -test and Chi-square test, respectively. Survival and freedom from adverse events were calculated by using a Kaplan–Meier method.

Results:

The overall in-hospital mortality was 2.8% (18/647) while there were 34 deaths (5.6%, 34/605) in the follow-up stage after discharge. The overall survival rate was 94.6% and 82.7% at 5 years and 10 years, respectively. The cumulative survival rate of 10 years was 82.8% in AVR group, 84.4% in MVR group, and 78.4% in DVR group. The overall rate of freedom from reoperations was 95.5% at 5 years and 86.8% at 10 years. The freedom from reoperation at 10 years was 87.0%, 88.1%, and 84.0% in AVR, MVR, and DVR group, respectively. The freedom from morbidities at 10 years was: 90.3% for thromboembolism, 95.2% for hemorrhage, 97.5% for prosthesis endocarditis, 95.9% for paravalvular leak, and 94.6% for structural valve deterioration, respectively.

Conclusions:

Hancock II bioprosthesis exhibited a satisfactory mid- to long-term durability and promising clinical performance in the Chinese population. The occurrence rates of death and other adverse events in this single-center study were overall coincident and quite acceptable when compared with existing data.

The Mosaic Mitral Valve Bioprosthesis: A Long-Term Clinical and Hemodynamic Follow-Up

We reviewed the cases of 100 patients (mean age, 73 ± 10 yr; 64 men) who had mitral valve replacement with a Medtronic Mosaic porcine bioprosthesis from 1995 through 2011. The mean New York Heart Association (NYHA) class was 3 ± 0.7, and 52 patients were in atrial fibrillation. Prosthetic sizes were chiefly 27 mm (50 patients) and 29 mm (40 patients). Follow-up ended in December 2012 and is 97% complete, with a cumulative duration of 611 patient-years (mean duration, 6 ± 4.6 yr; maximum, 17.7 yr). The early mortality rate was 10% (6% in elective patients); late deaths occurred in 31 patients (5 valve-related). Actuarial survival rates at 5, 10, and 15 years were 74% ± 5%, 50% ± 6%, and 37% ± 8%. The mean NYHA class in survivors was 1.4 ± 0.6 (P <0.0001). Thromboembolic episodes occurred in 4 patients, with an actuarial freedom at 15 years of 91% ± 5%. No cases of endocarditis were observed. Four patients needed reoperation, 2 for structural failure, and 1 each for perivalvular leakage and valve thrombosis. Actuarial freedom from structural failure and from reoperation, respectively, was 93% ± 5% and 91% ± 5% at 15 years. Echocardiographic follow-up in 24 patients with 27-mm prostheses showed a mean gradient of 5 ± 1.7 mmHg and an effective orifice area of 1.57 ± 0.3 cm(2); in 16 patients with 29-mm prostheses, the mean gradient was 4.5 ± 1.9 mmHg, and the effective orifice area, 1.63 ± 0.4 cm(2). During nearly 17 years of follow-up, the Mosaic bioprosthesis has shown good overall clinical and hemodynamic performance after mitral valve replacement.

Subvalvular Pannus Overgrowth after Mosaic Bioprosthesis Implantation in the Aortic Position

PURPOSE

Although pannus overgrowth by itself was not the pathology of structural valve deterioration (SVD), it might be related to reoperation for SVD of the bioprostheses.

METHODS

We retrospectively reviewed patients undergoing reoperation for SVD after implantation of the third-generation Mosaic aortic bioprosthesis and macroscopic appearance of the explanted valves was examined to detect the presence of pannus.

RESULTS

There were 10 patients and the age for the initial aortic valve replacement was 72 ± 10 years old. The duration of durability was 9.9 ± 2.0 years. Deteriorated valve presented stenosis (valvular area of 0.96 ± 0.20 cm(2); pressure gradient of 60 ± 23 mmHg). Coexisting regurgitant flow was detected in two cases. Macroscopically, subvalvular pannus overgrowth was detected in 8 cases (80%). The proportion of overgrowth from the annulus was almost even and pannus overgrowth created subvalvular membrane, which restricted the area especially for each commissure. In contrast, opening and mobility of each leaflet was not severely limited and pannus overgrowth would restrict the area, especially for each commissure. In other two cases with regurgitation, tear of the leaflet on the stent strut was detected and mild calcification of each leaflet restricted opening.

CONCLUSION

In patients with the Mosaic aortic bioprosthesis, pannus overgrowth was the major cause for reoperation.

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).

Late haemodynamic performance and survival after aortic valve replacement with the Mosaic bioprosthesis

OBJECTIVES

The objective was to evaluate the long-term haemodynamic performance of the Mosaic aortic bioprosthesis. Secondary objectives were to investigate the long-term survival, the rate of aortic valve reoperations, and the rate of prosthesis-patient mismatch and its effect on long-term survival.

METHODS

We included all patients who underwent aortic valve replacement with a Mosaic bioprosthesis at our institution between 2002 and 2008. Valve haemodynamics were assessed by transthoracic echocardiography as mean and peak pressure gradients. Patient characteristics and outcomes were collected from charts and national registers.

RESULTS

We included 355 patients and echocardiographic evaluation was performed at early follow-up in 340 patients (96%) and at late follow-up in 161 patients (45%). The mean follow-up time was 7.1 (maximum 11.7) years. The unadjusted survival at 1, 5 and 10 years was 92, 79 and 42%, respectively. At the early postoperative echocardiography, the peak pressure gradient was 39.9 mmHg (SD 14.4) and the mean pressure gradient was 21.1 mmHg (SD 7.7) and, on late echocardiography, the peak pressure gradient was 38.6 mmHg (SD 15.6) and the mean pressure gradient was 22.5 mmHg (SD 10.1). Moderate or severe prosthesis-patient mismatch was found in 250 (70%) and 49 patients (14%), respectively, but was not significantly associated with mortality in multivariable analyses.

CONCLUSIONS

We found that the Mosaic aortic bioprosthesis had acceptable clinical performance at late follow-up. However, a substantial proportion of patients had high transvalvular gradients or moderate or severe prosthesis-patient mismatch, although neither were significantly associated with long-term survival in our population.

Late survival after aortic valve replacement with the perimount versus the mosaic bioprosthesis

BACKGROUND

The objective was to compare late survival after aortic valve replacement (AVR) with a Carpentier-Edwards Perimount (Edwards Lifesciences, Irvine, CA) versus a Mosaic bioprosthesis (Medtronic Inc, Minneapolis, MN). Secondary objectives were to compare early mortality, the rate of reoperation, and the effect of prosthesis-patient mismatch (PPM) on late survival.

METHODS

The design was a population-based cohort study including all patients who underwent AVR with a Perimount or Mosaic bioprosthesis at our institution between 2002 and 2010. Baseline, operative characteristics and clinical outcomes were collected from patient charts and national registers. The primary outcome was all-cause mortality. We analyzed the unadjusted and multivariable adjusted association between valve type and late survival.

RESULTS

In total, 1,219 patients received the Perimount (n=864) or the Mosaic (n=355) bioprosthesis. During a mean follow-up of 4.2 and 6.9 years, there were 193 and 177 deaths in the Perimount and Mosaic groups, respectively. The unadjusted 1-, 5-, and 8-year survival was 93%, 78%, and 63%, respectively, in the Perimount group and 92%, 80%, and 57%, respectively, in the Mosaic group (p=0.971).There was no significant association between valve choice and all-cause mortality in the multivariable analysis (hazard ratio [HR], 0.85; 95% confidence interval [CI], 0.65-1.11). Freedom from aortic valve reoperation was similar between the groups. No significant association was found between severe PPM and late mortality.

CONCLUSIONS

We found no significant difference in late survival after AVR with a Perimount bioprosthesis compared with a Mosaic bioprosthesis. Even though severe PPM was more common in the Mosaic group, it did not affect the late survival or the frequency of reoperation.

New CoreValve Evolut 23 mm technology for treatment of degenerated bioprosthesis

The treatment of degenerated surgical bio-prosthetic heart valves (BHV) has been reported as a novel indication for TAVI. The intervention may be complicated by high residual transvalvular gradients and coronary ostia obstruction, especially in small size BHV. We report two cases of BHVs treated with the new CoreValve Evolut 23 mm highlighting the importance of fluoroscopic guidance, based on BHV markers, in achieving a correct TAVI implantation. The small dimensions of the new CoreValve Evolut 23 allowed us to obtain low residual gradients even in this particular subset of degenerated BHV.