Long-Term Outcomes and Durability of the Mitroflow Aortic Bioprosthesis

Ten-year clinical and echocardiographic follow-up of third-generation biological prostheses in the aortic position

OBJECTIVES

PERIMOUNT Magna Ease (Carpentier-Edwards; PME) prostheses have been widely implanted during the past decade for aortic valve replacement (AVR). Although promising results at midterm follow-up were reported, long-term outcome has yet to be confirmed. On this study we aimed to evaluate long-term results in terms of structural valve degeneration (SVD), major clinical outcomes, long-term hemodynamic valve performance, and left ventricular remodeling.

METHODS

From 2010 to 2012, 689 consecutive patients underwent AVR with PME. Complete clinical 10-year follow-up was obtained. The degree of SVD was categorized on the basis of the latest guidelines. Echocardiographic data were analyzed at 1, 5, and 10 years. Competing risk analysis was performed for major events. Cumulative incidence of SVD, reoperation, and endocarditis were also assessed according to prosthetic sizes (19-21-23 mm vs 25-27-29 mm) and age (<65 vs 65-75 vs >75 years old).

RESULTS

The overall cumulative incidence reported for SVD ≥2 and reoperation were 3.6% and 1.9% at 10 years, respectively. An early left ventricular reverse remodeling was noted after implantation and confirmed at follow-up. Patients younger than 65 years showed higher cumulative incidence of SVD ≥2 at 10 years compared with patients aged 65 to 75 and older than 75 years (9.7% vs 2.6% vs 2.7%; P = .013), as well as of redo AVR (7.8% vs 3.3% vs 0.4%; P = .002). There was no difference in terms of SVD and redo AVR for different prosthetic size categories (P > .05). The risk of endocarditis was similar among age and size groups.

CONCLUSIONS

PME provides very good durability at long-term and could be considered one of the high performing third-generation bioprostheses for AVR.

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).

The pathology of early failure in Mitroflow pericardial valve bioprosthesis (12A/LX)

BACKGROUND

Limited mid-term durability of 12A/LX Mitroflow bioprosthesis has been reported. Aim of the study was to ascertain the pathologic substrates and possible mechanisms of structural valve deterioration in explants from animals and humans.

METHODS

Nine aortic 12A/LX Mitroflow bioprostheses preserved in hypotonic solution and three aortic 12A/LX bioprostheses, preserved in isotonic solution, were explanted from juvenile sheep, mean time from implant 95.66 ± 36.04 days and 132.33 ± 28.88 days from implant respectively. One stented unimplanted 12A/LX Mitroflow preserved in isotonic colution before glutaraldeyde fixation served as control. Ten aortic 12A/LX Mitroflow bioprostheses were explanted from humans because of severe dysfunction: five children, (3 females and 2 males, mean age 14.19 ± 4.77 years, range 11-21), 26 ± 8.24 months from implant and 5 adults (4 females and 1 male, mean age 57.4 ± 19.85 years, range 31-72), 64.4 ± 26.94 months from implant. X-ray, histology, and transmission electron microscopy were carried out as well as spectroscopy for calcium (Ca++) and phosphorus (P) content in human explants.

RESULTS

Explants, from both animals and humans, showed cusp folding and stiffness, with coarse calcific deposits at gross examination and X-ray. Severe collagen denaturation, plasma insudation and massive calcification, involving both collagen and cell debris, were observed microscopically. Mean Ca++ content of 183.27 ± 62.48 and P content of 94.35 ±33.76 mg/g dry weight was found in children and Ca++ content of 205.49 ± 2.23 and P content of 99.75 ± 0.11 mg/g dry weight in adults. Obstructive fibrous tissue overgrowth was detected in 6 human cases.

CONCLUSIONS

Collagen denaturation was observed in pericardial Mitroflow 12A/LX bioprosthesis with premature structural valve deterioration. Optimal collagen fixation and preservation as well as phospholipids reduction by removing cell debris, as employed in the novel CROWN PRT Mitroflow bioprosthesis, are expected to solve the flaw and achieve long-term durability.

Severe Aortic Regurgitation of Early Degenerated Mitroflow Bioprosthesis: From Echocardiographic Diagnosis to Treatment with Valve-in-Valve Transcatheter Aortic Valve Implantation

Valve-in-Valve transcatheter aortic valve implantation (ViV TAVI) is emerging as an effective therapeutic option for bioprosthetic valve failure. Recently, concern has been raised for early valve deterioration of Mitroflow (Sorin) aortic bioprosthesis, with the development of prevalent stenosis. We report cases of pure severe aortic regurgitation (AR) due to early and mid-term prosthesis degeneration. From June 2018 to October 2019, three patients were treated in our division for the new appearance of severe intraprosthetic regurgitation. Patient 1 (man, 85-year-old) and patient 3 (woman, 83-year-old) had a Mitroflow n. 25 and n. 21 implanted, respectively, in 2012 and 2013 for severe aortic stenosis. Patient 2, a 67-year-old woman with Marfan syndrome underwent a Mitroflow n. 25 implant in 2008 for severe AR and presented chronic type-B aortic dissection. Patient 1 was diagnosed with severe AR in the ambulatory setting, while the other patients presented acute heart failure, requiring inotrope support and high doses intravenous diuretics, and in case 3, temporary extracorporeal ultrafiltration. All patients appeared at high surgical risk and were successfully treated with ViV TAVI, through the right axillary artery in patient 2, and through the femoral artery in patients 1 and 3. Results were good at short- and mid-term follow-up. In conclusion, early and midterm bioprosthesis degeneration with the development of severe AR is a possible complication of the Mitroflow aortic valve. ViV TAVI has been confirmed as a safe and effective therapeutic option in our cases.

Fifty years of the pericardial valve: Long-term results in the aortic position

It is now 50 years since the development of the first pericardial valve in 1971. In this time significant progress has been made in refining valve design aimed at improving the longevity of the prostheses. This article reviews the current literature regarding the longevity of pericardial heart valves in the aortic position. Side by side comparisons of freedom from structural valve degeneration are made for the valves most commonly used in clinical practice today, including stented, stentless, and sutureless valves. Strategies to reduce structural valve degeneration are also discussed including methods of tissue fixation and anti-calcification, ways to minimise mechanical stress on the valve, and the role of patient prosthesis mismatch.

Balloon-expanding transcatheter aortic valve implantation for degenerated Mitroflow bioprostheses: clinical and echocardiographic long-term outcomes

OBJECTIVES

This study aims to analyse the risks associated with valve-in-valve procedures for treating structural valve deterioration in Mitroflow bioprostheses, as well as to determine the impact of the original Mitroflow size on the patients' long-term outcomes.

METHODS

Between January 2012 and September 2019, 21 patients (61.9% males; mean age 82.4 ± 5.4 years) were treated for Mitroflow deterioration with valve-in-valve procedures (12 transapical and 9 transfemoral).

RESULTS

Mean EuroSCORE I and EuroSCORE II were 28.2% ± 13.6% and 10.5% ± 6.1%, respectively. Six patients presented an indexed aortic root diameter <14 mm/m2 and 7 patients a diameter of sinus of Valsalva <30 mm. Implanted transcatheter valve sizes were 20 mm in 6 cases, 23 mm in 14 cases and 26 mm in 1 patient. A Valve Academic Research Consortium-2 complication occurred in 23.8% of cases, including 3 coronary occlusions. In-hospital mortality was 9.5%. The 20 mm transcatheter valves presented significantly higher postoperative peak and mean aortic gradients than other sizes (54.1 ± 11.3 mmHg vs 29.9 ± 9.6 mmHg, P = 0.003; and 29.3 ± 7.7 mmHg vs 17.4 ± 5.9 mmHg, P = 0.015, respectively). There were 12 cases of patient-prosthesis mismatch (57.1%) and 3 cases (14.3%) of severe patient-prosthesis mismatch. Cumulative survival was 85.7% ± 7.6% at 1 year, 74.3% ± 10% at 2 years and 37.1% ± 14.1% at 5 years.

CONCLUSIONS

Valve-in-valve procedures with balloon-expandable transcatheter valves associate a high risk of coronary occlusion in patients with indexed aortic root diameter <14 mm/m2 and low coronary ostia <12 mm. Valve-in valve procedures with 20 mm balloon-expandable transcatheter valves in ≤21 mm Mitroflow bioprosthesis leave significant residual transvalvular gradients that might obscure patients' long-term outcomes.

Magna ease bioprosthetic aortic valve: mid-term haemodynamic outcomes in 1126 patients

OBJECTIVES

The Magna Ease aortic valve (Edwards Lifesciences, Irvine, CA) is a third-generation bioprosthetic valve developed as a modification of the well-studied Perimount and Magna valve designs. This study's objective is to evaluate a large, single-centre experience with Magna Ease aortic valve replacement (AVR) focusing on clinical outcomes and haemodynamic performance.

METHODS

All patients undergoing AVR between 8/2010 and 10/2018 at our institution implanted with the Magna Ease valve were included except those undergoing ventricular assist device or congenital aortic surgery. Primary outcomes were overall survival and freedom from reoperation. Mean transprosthetic gradient (mTPG) and structural valve deterioration (SVD) served as secondary outcomes.

RESULTS

Totally 1126 consecutive implantations of Magna Ease valves were included. Concomitant procedures were performed in 56.5% (n = 636). No severe patient-prosthesis mismatch (PPM) was present at implantation. Overall survival at 30 days, 1 year, 5 years and 9 years was 97.2%, 95.0%, 86.1% and 78.2%, respectively, with improved survival for isolated AVR. Total of 2.4% (n = 27) of patients required reoperation with 0.3% (n = 4) for SVD. Echocardiographic follow-up data revealed low mTPG throughout the study period. SVD occurred in 28.7% of patients at a mean of 3.9 years post implantation.

CONCLUSIONS

Magna Ease AVR maintained low mean transprosthetic gradients throughout mid-term evaluation and was associated with excellent overall survival and freedom from reoperation at nine years post implantation.

Influence of Mitroflow bioprosthesis structural valve deterioration on cardiac morbidity

Background

This study investigated the extent and nature of cardiac morbidity and cause of mortality in patients with Mitroflow structural valve deterioration (SVD).

Methods

A retrospective study was performed examining the medical records of patients who had received Mitroflow bioprosthesis between February 2001 and April 2014 and died during this period. A total of 211 patients were identified and included in the analyses. To determine the cause of mortality, cases were divided into three predefined groups: cardiovascular death due to SVD (group 1), cardiovascular death with no SVD (group 2) and non-cardiovascular death without SVD (group 3).

Results

Overall mortality in this study was 7.6% at 1 year, 46.4% at 5 years and 97.2% at 10 years. In group 1, 53 patients (25%) died; in group 2, 59 patients (28%) died; and in group 3, 99 patients (47%) died. Hospitalisation for congestive heart failure was observed in 49.1% in the SVD group vs. 10.2 and 13.1% in the two other groups, p < 0.001. Hospitalisation for endocarditis was also significantly higher in the SVD group (11.3%) than in the two other groups (6.8 and 0%), p < 0.05. Hospitalisation due to myocardial infarction, cerebral stroke, arrhythmia or other cardiac-related diseases was not significantly different between groups.

Conclusion

Structural valve deterioration in Mitroflow bioprosthesis was associated with a high prevalence of hospital admissions due to congestive heart failure and endocarditis. Patients with Mitroflow bioprosthesis should be systematically and routinely followed with echocardiography, and reoperation should be considered if SVD has developed.

Structural valve deterioration in the Mitroflow biological heart valve prosthesis

OBJECTIVES

Concern has been raised regarding the long-term durability of the Mitroflow biological heart valve prosthesis. Our aim was to assess the incidence of structural valve degeneration (SVD) for the Mitroflow bioprosthesis in a nationwide study in Denmark including all patients alive in Denmark who had received a Mitroflow aortic bioprosthesis since 2000.

METHODS

Patients alive in Denmark with a Mitroflow bioprosthesis implanted since January 2000 were invited to participate in a nationwide cross-sectional study with a predefined definition of SVD. Of 1552 patients, 861 patients had died and 47 patients had been reoperated with 40 reoperations due to SVD. The remaining 644 patients were invited for evaluation; 574 patients accepted and were evaluated for SVD. The incidence of SVD was calculated using competing risk regression analysis with death as the competing event.

RESULTS

A total of 173 patients were diagnosed with SVD by echocardiography. Of these, 64 (11%) patients had severe SVD and 109 (19%) patients moderate SVD. Severe SVD was associated with the age of the prosthesis and small prosthesis size [Size 21: hazard ratio (95% confidence interval, CI) 2.72 (0.97-8.56), P = 0.06; Size 19: 6.26 (1.63-24.06), P = 0.008]. The cumulative incidences of reoperation or severe SVD at Year 9 were 12.5% for Size 19, 7.6% for Size 21 and 3.1 (1.2-6.4)% for Size 23. Median survival in patients with prosthesis Sizes 23-29 was 6.4 (95% CI 5.7-7.0) years, with Size 21 it was 6.5 (95% CI 5.9-7.1) years and with Size 19 it was 6.9 (95% CI 5.7-8.2) years (P = 0.78).

CONCLUSIONS

The incidence of undetected severe SVD was as high as the incidence of operated SVD. The overall risk for SVD is high for the Mitroflow bioprosthesis, especially if the prosthesis is small and older than 5 years.

Early structural degeneration of Mitroflow aortic valve: another issue in addition to the mismatch?

We reported two cases of early structural valve degeneration (SVD) with Mitroflow prosthesis in aortic position in patients above the age of 65 years. Microscopic aspects have been analysed to investigate the intrinsic mechanism of SVD. New techniques to improve the structure and the preservation of this prosthesis are needed in order to reduce potential dangerous early complications.