Mitroflow Aortic Bioprosthesis Research Articles

Early degeneration of the Sorin Mitroflow aortic bioprosthesis

Early degeneration of the Sorin Mitroflow aortic bioprosthesis

P1362 Echocardiographic findings and BNP levels in patients with valve-in-valve implantation in small failed mitroflow aortic prosthesis

Abstract BACKGROUND Early structural valve deterioration (SVD) frequently occurs in Mitroflow aortic bioprosthesis, especially for small sizes (19-mm and 21-mm), and it is associated with reduced overall survival. Treatment by percutaneous valve-in-valve (ViV) implantation is considered a challenging procedure. This is mainly due to an elevated risk of coronary ostia obstruction and high residual post-procedural mean gradients (mG), particularly when severe pre-existing patient-prosthesis mismatch (PPM) is present. PURPOSE Aim of our study was to assess the feasibility of transfemoral ViV in small Mitroflow aortic valves using supra-annular self-expanding valves, named CoreValve and Evolut R and Acurate neo and report the midterm clinical results by comparing serum natriuretic peptide type B levels (BNP) before the procedure and at a mean follow-up of 2 years. METHODS This is an observational study including 11 patients with stenotic-type SVD of small Mitroflow aortic valves, considered at high/prohibitive risk for surgical reoperation, who underwent ViV implantation between July 2012 and March 2018. We performed echocardiographic assessment of valve hemodynamics (according to VARC-2 definitions) before and after the procedure and during the follow-up. We used the BNP ratio (the ratio between measured serum BNP/NT-proBNP level and maximal normal level) to compare BNP results before the procedure and at follow-up. All-cause mortality during the hospitalization and follow-up was also reported. RESULTS The Mitroflow size was 19-mm in 4 patients and 21-mm in 7 patients. Pre-existing severe PPM was present in 4 patients and moderate PPM in 7. CoreValve 26 was implanted in 2 patients, EvolutR 23 in 5 and Acurate neo S in 4 patients. We reported no coronary obstruction, deaths or other major events during the hospitalization. At a mean follow-up of 2 years one patient died. The baseline aortic mG of 56 ± 19 mmHg has significantly reduced after the procedure to 16,6 ± 8 mmHg (p < 0.0001) and follow-up 29,6 ± 16 mmHg (p = 0.008). A post-procedural mG≥20, but <40 mmHg, was observed in 3 patients. BNP ratio at baseline was 14,6 ± 12; only one patient had a BNP ratio <3. At follow-up (n = 7 patients), BNP ratio was significantly lowered to 1,5 ± 1,08 (p = 0.01) with only one patient with a BNP ratio >3. Patients with mPG ≥20 mmHg did not show differences in terms of mortality and reduction of serum BNP levels. CONCLUSIONS In our experience the ViV procedure on small degenerated aortic Mitroflow bioprosthesis appears to be technically feasible and provides good midterm clinical results with a net reduction in serum BNP levels, although an increase in mG was observed. Even though a post-procedural mG ≥20 mmHg is considered indicative of suboptimal aortic valve hemodynamics (according to VARC-2 criteria), its correlation with worse outcomes remains unclear and deserves further investigations.

Early structural valve deterioration and reoperation associated with the mitroflow aortic valve.

Structural valve deterioration (SVD) is a known limitation of bioprosthetic valves. Recent reports have suggested a concerning rate of early SVD in patients receiving a Mitroflow aortic bioprosthesis. We therefore compared the incidence of SVD and SVD requiring reoperation among patients receiving a Mitroflow versus a common contemporary bioprosthesis. A retrospective cohort analysis was performed on 592 patients receiving a Mitroflow aortic bioprosthesis at our institution between 2010 and 2014. Patients were matched 1:1 using a coarsened exact matching algorithm with patients receiving a Carpentier-Edwards Magna Ease aortic bioprosthesis (Edwards Lifesciences, Irvine, CA) during the same period. The incidence of SVD (defined as a mean transprosthetic gradient ≥30 mmHg or moderate to severe intraprosthetic regurgitation), reoperation for SVD, and cumulative survival were compared between prosthesis types. The cumulative incidence of SVD at 5 years for all patients receiving a Mitroflow aortic bioprosthesis was 16% (13-21%) and 5% underwent reoperation for SVD. Implantation of a Mitroflow valve was associated with an increased risk of SVD compared to the comparator valve (hazard ratio [HR] 2.59 [1.69-3.98], P < 0.01). Older age had a protective effect against SVD (HR 0.95 [0.93-0.96], P < 0.01). Patients who received a Mitroflow valve had reduced long-term survival compared to those who received a comparator valve (P = 0.03). The Mitroflow aortic bioprosthesis is associated with increased rates of early SVD and reoperation for valvular dysfunction as well as reduced survival compared to a contemporary valve. Enhanced clinical and echocardiographic follow-up is advisable after Mitroflow implantation.

Efficacy and safety of transcatheter valve-in-valve replacement for Mitroflow bioprosthetic valve dysfunction.

Bioprostheses with pericardial leaflets mounted externally on the stent pose a high risk for valve-in-valve (ViV) procedures. This study analyzed the efficacy and safety of ViV procedures for treating structural valve deterioration (SVD) in Mitroflow bioprostheses. Between January 2012 and August 2017, 11 patients (mean age 80.3 ± 5.6 years) were treated for SVD of Mitroflow bioprostheses with transcatheter ViV procedures (six transapical [TA] and five transfemoral [TF]) using balloon expandable bioprostheses. All patients but one were in NYHA class III-IV. Mean STS PROM, euroSCORE I, and euroSCORE II were 8 ± 6.5%, 27.8 ± 11.5%, and 12 ± 5.9%, respectively. Two patients had a "porcelain aorta." The size of implanted valves were 23 mm in 10 cases and 26 mm in one case. One patient suffered a coronary occlusion during a TF approach. The mean volume of contrast used in TF implants was 163 ± 69.8 mL. No contrast media were used in TA procedures. There was one in-hospital death (10%). At 1 year of follow-up, peak and mean aortic gradients were 25.5 ± 5.8 mmHg and 15.5 ± 5.7 mmHg, respectively. One patient had mild paravalvular regurgitation. Cumulative survival was 90.9% at 1 year, 70.7% at 2 years, and 53% at 3 years. ViV procedures with balloon-expandable aortic valves provide good hemodynamic and clinical mid-term results for treating patients with a degenerated Mitroflow aortic bioprosthesis. Special care must be taken in small aortic roots, when the stented valve is in the supra-annular position to avoid coronary ostial obstruction.

Sutureless prosthesis for failed small Mitroflow valves: the Perceval-after-Mitroflow procedure.

Because of its favourable haemodynamic characteristics and easy implantability, Mitroflow aortic valve bioprosthesis has been the valve of choice for many surgeons in patients with small aortic annulus. Disappointingly, early structural valve deterioration and high transvalvular gradients have been reported mostly in older patients with small prostheses. Reimplanting a new stented prosthesis sutured in a narrow and damaged annulus is technically challenging and demanding mainly in high-risk patients. Valve-in-valve transcatheter aortic valve implantation has been proposed as a viable option; however, it presents significant limitations because of residual high transprosthetic pressure gradients and risk of coronary occlusion. We report a series of 8 patients, with medium-term follow-up, who underwent successful Perceval-S surgical sutureless aortic implant after the removal of a degenerated small Mitroflow valve. No early mortality occurred, but 1 patient died 4 months postoperatively due to gastrointestinal disease. No major complications occurred. Early and mid-term postoperative pressure gradients were low (mean gradients 13.1 ± 3.3 mmHg and 10.2 ± 3.8 mmHg, respectively). In operable patients with a degenerated Mitroflow valve, these favourable clinical and haemodynamic results suggest that the sutureless solution is a simple, valid and safer alternative to conventional redo valve replacement or to valve-in-valve transcatheter aortic valve implantation.

Structural valve deterioration in the Mitroflow biological heart valve prosthesis.

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. 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. 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). 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.

Long-term results of the Mitroflow aortic pericardial bioprosthesis in over 800 patients: limited durability and mechanisms of dysfunction.

The Mitroflow aortic pericardial bioprosthesis was widely employed in the past. However, some authors have recently reported early structural valve deterioration (SVD) of the Mitroflow LA/LXA model. Thus, we reviewed our experience with the Mitroflow bioprosthesis and studied the risk factors for SVD and mortality. Records of patients who underwent aortic valve replacement with a Mitroflow bioprosthesis between November 2005 and January 2015 were retrospectively evaluated with Kaplan-Meier, Cox-regression and multistate analysis. Only patients with a complete clinical follow-up were included in the study. Average follow-up was 45 months and ended on 1 April 2016. Between November 2005 and January 2015, among the 916 patients undergoing aortic valve replacement with the Mitroflow prosthesis at our Institution, the 832 (90.8%) patients with follow-up information were included into the study. Fifty-two (6.2%) patients developed SVD (stenosis, n = 38; regurgitation, n = 7; mixed, n = 7). Freedom from SVD was 95.4% and 67.9%, at 5 and 9 years, respectively, without differences after stratification according to the prosthesis model ( P = 0.87) and prosthesis size ( P = 0.70). At the multivariable analysis, increasing age was identified as a protective factor against SVD (hazard ratio = 0.94, P < 0.001). Twenty (38.4%) patients with SVD underwent redo aortic valve replacement. At 5 and 9 years, survival was 64.5% and 43.1%, repectively. According to the multistate analysis, the fraction of patients living with degenerated valves at 9 years was 10.0%; 7.1% died following degeneration. The LA/LXA Mitroflow model showed limited long-term durability. Degenerated prostheses showed more stenosis than regurgitation. Patient age played an important role in the development of SVD.

Ten-year results of aortic valve replacement with first-generation Mitroflow bioprosthesis: is early degeneration a structural or a technical issue?

Concerns have been raised about the durability of the first-generation Mitroflow aortic bioprosthesis (model 12 A-LX) due to the lack of anticalcification treatment. This study reflects a 10-year experience with this prosthesis for aortic valve replacement. From June 2003 to May 2012, the Mitroflow prosthesis was used for aortic valve replacement in 510 patients, of whom only 467 with complete clinical follow-up were included for analysis. Study end-points were survival and incidence of structural valve degeneration (SVD). Analysis of SVD was based on cumulative incidence function and competing-risk Cox regression. The mean patient age was 76.4 ± 6.1 years. Valve sizes from 23 to 25 were used in 70.4%, whereas sizes from 19 to 21 were used in only 19.2%, thereby avoiding patient-prosthesis mismatch in 89.1%. Within a median follow-up time of 6.6 years (interquartile range 4.4), a cumulative 2375 patient-years, the survival rate was 86.2%, 67.3% and 33.3% at 1, 5 and 10 years, respectively. The cumulative incidence of SVD, with death as a competing risk, was 0%, 0.7% and 6.2% at 1, 5 and 10 years, respectively. Only age <75 years tended to affect the late hazard of SVD (hazard ratio 0.50, 95% confidence interval 0.23-1.08, P = 0.08), regardless of valve-specific issues. The data do not support the concerns about early accelerated structural degeneration of the first-generation Mitroflow bioprosthesis used for aortic valve replacement in patients older than 75 years. We postulate that limiting the number of small prostheses using a proper implantation technique has enhanced the reduction in risk of significant patient-prosthesis mismatch as the main determinant of early SVD.

Long-Term Outcomes and Durability of the Mitroflow Aortic Bioprosthesis.

This study aims to determine the incidence and causes of structural valve deterioration (SVD) among all models of Mitroflow bioprostheses (A12/LX/DL), as well as to define their long-term clinical and hemodynamic performance. We retrospectively reviewed a series of 1023 patients who underwent aortic valve replacement with Mitroflow bioprostheses between 2001 and 2014. A small aortic root was found in 22.4% of patients. There were two cases of severe patient-prosthesis mismatch. Only 31 patients developed SVD. The rate of incidence was 8.1 cases per 1000 patient-years. Cumulative incidence of SVD was 1.4% and 3% at five and 10 years, respectively. Freedom from SVD was 97.4% and 88.2% at five and 10 years, respectively. Anticalcification phospholipid reduction treatment (PRT) for model DL was a protective factor for SVD. Multivariable analysis confirmed age <70 years and use of 19 mm valve as independent predictors of SVD. Cumulative survival was 76.6% at five years and 42.3% at 10 years (mean follow-up 3.8 ± 3.1 years). In multivariable analysis, neither the use of small aortic prosthesis (p = 0.18) nor the occurrence of SVD (p = 0.85) was found to be independent predictors of long-term survival. Mitroflow valves demonstrate an acceptable rate of SVD and satisfactory long-term hemodynamic performance, particularly in patients with small aortic roots, age >70 years, and cases with severe left ventricular hypertrophy. PRT might contribute to improved long-term durability. doi: 10.1111/jocs.12726 (J Card Surg 2016;31:264-273).

Fate of aortic bioprostheses: An 18-year experience

ObjectiveTo report our experience in aortic valve replacement with the Mitroflow (Sorin, Vancouver, Canada) aortic bioprosthesis. MethodsWe retrospectively reviewed all patients who underwent aortic valve replacement with a Mitroflow bioprosthesis at our institution from January 1994 to December 2011. No exclusion criteria were retained. Patients were followed yearly. Echocardiography follow-up was performed systematically before the hospital discharge and annually by patients' cardiologists. ResultsSeven hundred twenty-eight patients (mean age, 76 ± 6 years; range, 33-91 years) underwent aortic valve replacement with Mitroflow 12A or LX model and were included in this analysis. 30-day mortality for nonemergent isolated aortic valve replacement was 5.5%. Eight patients (1%) underwent reoperation for structural valve deterioration (SVD) and 30 patients (5.8%) presented echocardiographic signs of SVD. Actuarial freedom from reoperation for SVD was 99% ± 0.5% and 95% ± 5% at 10 and 15 years. Actuarial freedom from echocardiographic signs of SVD was 77% ± 5% and 56% ± 11% at 10 and 15 years, respectively. At the univariate analysis, only the mean gradient at discharge (P = .0200), the prevalence of size 19 (P = .0273), and severe patient–prosthesis mismatch (P = .0384) were significantly different in patients developing SVD at follow-up. Freedom from echocardiographic signs of SVD at 8 years were 88% ± 4% and 64% ± 13% in patients with a Mitroflow > 19 and Mitroflow 19, respectively (log-rank test, P = .0056; Wilcoxon test, P = .0589). ConclusionsOverall outcomes were satisfactory. However the risk of early SVD seems higher for the Mitroflow size 19. This size should be reserved for applications when annulus enlargement is risky or there is an anatomic contraindication to sutureless or stentless valve.

Early structural valve deterioration of Mitroflow aortic bioprosthesis: mode, incidence, and impact on outcome in a large cohort of patients.

Structural valve deterioration (SVD) is a major flaw of bioprostheses. Early SVD has been suspected in the last models of Mitroflow bioprosthesis. We sought to assess the incidence, mode, and impact of SVD on outcome in a large series of Mitroflow aortic valve replacement. Six hundred seventeen consecutive patients (aged 76.1±6.3 years) underwent aortic valve replacement with a Mitroflow prosthesis (models 12A/LX) between 2002 and 2007. By echocardiography, 39 patients developed early SVD (1.66% per patient-year), with stenosis as the main mode (n=36). Mean delay to SVD was only 3.8±1.4 years, and 5-year SVD-free survival was 91.6% (95% confidence interval [CI], 88.7-94.7) for the whole cohort and 79.8% (95% CI, 71.2-89.4) and 94.0% (95% CI, 90.3-97.8) for 19- and 21-mm sizes, respectively. Among the 39 patients with SVD, 13 patients (33%) had an accelerated SVD once the mean gradient exceeded 30 mm Hg. Valve-related death was 46.2% in this SVD subgroup. Five-year overall survival was 69.6% (95% CI, 65.7-73.9). In multivariable analysis, SVD was the strongest correlate of overall mortality (hazard ratio=7.7; 95% CI, 4.4-13.6). Early SVD is frequent in Mitroflow bioprosthesis (models 12A/LX), especially for small sizes (19 and 21 mm), and reduces overall survival. An unpredictable accelerated pattern of SVD constitutes a life-threatening condition. In view of the large number of Mitroflow valves implanted worldwide, one can expect an epidemic of SVD and valve-related deaths, which represents a major public health issue, especially in the elderly. Hence, a close follow-up with yearly echocardiography after Mitroflow implantation is advisable. An urgent reoperation should be discussed in patients with severe SVD even though they are still asymptomatic.

Early Structural Valve Deterioration of the Mitroflow Aortic Bioprosthesis

There has been a trend toward more frequent use of bioprosthetic valves, especially in the young generations, over the last decade.1,2 According to the Society of Thoracic Surgeons database, use of bioprosthetic valve increased from 44% in 1996 to 78% in 2006 in North America.1 Freedom from warfarin use and restrictions on diet and activities make bioprosthetic valves more attractive and popular, and multiple reports have shown that choosing a bioprosthetic valve does not decrease survival despite the increased rate of reoperation.3,4 Article see p 2012 The Mitroflow aortic prosthesis (Sorin Group Inc) is one of the most frequently used bioprostheses, with >100 000 implanted worldwide.5 The bovine pericardium is mounted externally around the stent, which maximizes the flow relative to the stent size. The valve is placed in the supra-annular position compared with the intra-annular position in some of the other bioprostheses. These characteristics allow superior valve hemodynamics in the Mitroflow aortic valve, especially in those with a small aortic annulus (19 and 21 mm)6; therefore, the Mitroflow aortic valve is considered an ideal valve for patients with a small aortic root. The Achilles heel of the bioprosthetic valve is structural valve deterioration (SVD). Cusp tears and thickening, calcification, pannus formation, and thrombus lead to deterioration of the valve,7 which is the leading reason for reoperation in bioprosthetic valves. The rate of SVD differs among ages; valves implanted in younger patients degenerate faster. For patients >65 years of age, the 10-year freedom from SVD in new pericardial valves is typically >90%.8 In this issue of Circulation , Senage et al9 strike a note of warning …

Prosthetic valve endocarditis 6 months after transcatheter aortic valve implantation

Susceptibility to endocarditis after transcatheter aortic valve implantation (TAVI) has not yet been described. We report the first case of acute aortic prosthetic valve endocarditis in a patient undergoing transapical TAVI, successfully treated with surgery. In November 2009, an 83-year-old woman underwent TAVI (23 mm Edwards Sapien) with an uneventful postoperative course. After 6 months, her blood cultures tested positive for Enterococcus faecalis and a prosthetic aortic valve endocarditis was diagnosed following the identification of a large mobile vegetation with subvalvular abscess. The abscess cavity was closed with a pericardial patch, and the prosthetic aortic valve was replaced with a 23 mm Mitroflow aortic bioprosthesis, using a standard surgical procedure with cardiopulmonary bypass.

Balloon valuloplasty prior to transcatheter valve‐in‐valve implantation in a degenerated mitroflow aortic bioprosthesis

Transcatheter valve-in-valve implantation is an emerging treatment option for high-risk patients with failing aortic bioprostheses. The presence of the prosthesis stents is thought to prevent coronary artery obstruction, a known complication of transcatheter aortic valve implantation in the native aortic valve. The Sorin Mitroflow aortic bioprosthesis (Sorin Group, Saluggia, Italy) has a particular design in that the pericardial leaflets are mounted outside the valve stent. As a consequence, the pericardial leaflets of this prosthesis may be displaced well away from the stents during the deployment of transcatheter valves. This might explain why both the cases of coronary occlusion following valve-in-valve implantation reported to date occurred in patients with a malfunctioning Mitroflow bioprosthesis. We describe a patient with a malfunctioning 25 mm Mitroflow bioprosthesis successfully treated by percutaneous transcatheter valve-in-valve implantation, and discuss the role that balloon aortic valvuloplasty plays in the performance of this delicate procedure.

Mitroflow Aortic Bioprosthesis 5-Year Follow-Up: North American Prospective Multicenter Study

The Mitroflow valve (Sorin Group, Milan, Italy) has been in use since 1982 and has shown long-term durability in large studies from European centers but has not been studied for long-term hemodynamics in large standardized multicenter trials. This study sought to assess the hemodynamics of the Mitroflow valve by extending the duration of follow-up in an ongoing prospective multicenter trial conducted in North America. Six sites participated in this midterm study requiring annual follow-up and echocardiographic evaluation using a standardized transthoracic echocardiography acquisition protocol. There were 276 patients enrolled (age 74±8 years) and 54% were in New York Heart Association (NYHA) functional class III-IV. Follow-up from the time of valve implantation had a mean of 4.0±1.7 years with a cumulative follow-up of 1,102 patient-years. At 5 years of follow-up, 99% of patients were free of moderate or severe aortic regurgitation and 94% were in NYHA functional class I or II. Between baseline and 5 years, mean gradients increased an average of 0.4 to 4.3 mm Hg. The change in effective orifice area was appreciably small (-0.1 to -0.3 cm2) after 5 years. There were 57 deaths (4 early and 53 late) and 9 valve explants. The Mitroflow valve implanted in the aortic position has shown to be hemodynamically stable over a 5-year follow-up in an elderly population with a high prevalence of comorbid conditions.

Which available transapical transcatheter valve fits into degenerated aortic bioprostheses?

The transapical transcatheter aortic valve implantation (TA-TAVI) in degenerated aortic bioprosthesis is an emerging therapy for surgically non-amenable patients. However, the presence of different types of aortic bioprostheses (stented and stentless), available in different sizes (19-27 mm), can be at the origin of important mismatches between the malfunctioning, degenerated aortic valves and the inner stent-valves implanted through transapical accesses (23 and 26 mm Edwards Sapien transcatheter stent-valves). We report an emergency TA-TAVI treatment of a severely regurgitant degenerated 23 mm Mitroflow aortic bioprosthesis (Sorin Group, Milano, Italy) implanted seven years earlier in an 80-year-old lady, and we reviewed the current available literature about transapical 'valve-in-valve' procedures to analyze the hemodynamic results and the ideal 'prosthesis-to-prosthesis' match.

Hemodynamic Performance of Mitroflow Aortic Pericardial Bioprosthesis – Optimizing Management for the Small Aortic Annulus

Documentation of the hemodynamics of the Mitroflow aortic pericardial bioprosthesis has been incomplete. The aim of the study was to provide reference effective orifice areas for the implant calculation of effective orifice area indexes to avoid prosthesis-patient mismatch. Echocardiograms were evaluated in 55 patients (39 females, 16 males), mean age 77.0 +/- 6.9 years (range 51-90 years). The mean time of the studies was 11.0 months. The prosthesis sizes and numbers evaluated were 19 mm (n = 13), 21 mm (n = 19), 23 mm (n = 13) and 25 mm (n = 10). Peak aortic velocities averaged from 2.2 to 2.7 m/sec, mean gradients from 10.6 to 15.1 mmHg, peak gradients from 20.7 to 29.7 mmHg, and effective orifice area (EOA) from 1.4 to 1.8 cm (2). When accounting for the subaortic velocity, mean gradients averaged from 7.5 to 10.0 mmHg, and peak gradients averaged 15.1 to 23.5 mmHg. The effective orifice area indexes ranged from 0.8 to 1.0 cm (2)/m (2). The mean postoperative left ventricular mass index was 101.6 gm/m (2). The IN VIVO effective orifice areas by valve size of the Mitroflow aortic pericardial bioprosthesis provide the opportunity of avoiding obstructive characteristics for all valve sizes, including optimizing the management of the small aortic annulus.

Mitroflow aortic pericardial bioprosthesis — clinical performance☆☆☆

Advancing life expectancy with the increased prevalence of aortic valve degenerative disease brings the need for an aortic bioprosthesis with excellent haemodynamic performance and comparable durability. The Mitroflow bioprosthesis has been on the worldwide market, except in the United States, since 1982, while the current model (1991) has only recently gained regulatory approval in the latter country. This study was primarily performed to determine the durability of the current Mitroflow bioprosthesis. The contemporary Mitroflow bioprosthesis was implanted in 381 patients in three centres. The mean age was 76.4 years (range 53-91 years) and the mean follow-up period was 5.4+/-3.4 years, a total of 2048.7 years of evaluation. Prosthesis-patient mismatch (PPM) was classified by reference effective orifice area index categories: normal > or = 0.85 cm(2) m(-2) (53.9%), mild 0.84-0.76 cm(2) m(-2) (33.9%), moderate < or = 0.75-0.66 cm(2) m(-2) (11.7%) and severe < or = 0.65 cm(2) m(-2) (0.5%). The survival, at 10 years, was 39.9+/-7.9% for 50-69 years, 27.0+/-3.7% for 70-79 years and 16.6+/-4.4% for > or = 80 years (p=0.011). There was a trend (p=0.063) influencing survival for moderate-to-severe PPM. Of the independent predictors influencing survival--moderate-to-severe projected effective orifice area index (pEOAI) (Hazard Ratio (HR) 1.6, p=0.0142) and left ventricular dysfunction (ejection fraction < 35%) (HR 1.9, p=0.0193) were included. The 10-year freedom from structural valve deterioration (SVD) at explant assessing the same age groups as survival was not different (p=0.081). The 10-year actual/actuarial freedom from SVD, at explant was for > or = 60 years--94.4+/-1.4% (85.2+/-3.9%), for > or = 65 years--94.2+/-1.4% (85.0+/-4.0%), for 61-70 years--97.4+/-2.6% (95.7+/-4.3%) and for > 70 years--94.0+/-1.5% (83.2+/-4.6%). The Mitroflow external mounted, pericardial aortic bioprosthesis with documented excellent haemodynamics (especially for the small aortic root), demonstrates that prosthesis-patient mismatch in moderate and severe categories can essentially be eliminated, with durability performance comparable to other heterograft (porcine and pericardial) bioprostheses.

Mitroflow Synergy Prostheses for Aortic Valve Replacement: 19 Years Experience With 1,516 Patients

Pericardial prostheses have been used as valvular substitutes since 1975. They combine excellent hemodynamic characteristics with a low risk of valve failure during long-term observation. The aim of this article is to describe the clinical long-term performance of the Mitroflow Synergy pericardial valve (Sorin Group Inc, Mitroflow Division, Vancouver, Canada) in the aortic position for as long as 19 years. Data were obtained between February 1985 and April 2004 from patients with aortic heart valve replacements (n = 1,464) or from patients with replacements of existing prosthetic aortic valves (n = 52). The age group distributions are less than 70 years (n = 175); 70 to 74 years (n = 462); 75 to 79 years (n = 532); 80 to 84 years (n = 273); and greater than or equal to 85 years (n = 74). The cause of the aortic valve lesions was combined (insufficiency and stenosis) in the majority of patients (62.4%). Concomitant procedures were performed in 897 patients (59.2%) and coronary artery bypass grafting was the most common (53.5%). Mean follow-up was 5.5 +/- 0.09 years. Total follow-up was 8,408 patient-years. The early mortality (30 days) was 6.6% (n = 99) and late deaths were 60.8% (n = 921). Actuarial event-free rates at 5, 10, and 15 years of follow-up are given as mean +/- standard error for endocarditis: 96.9 +/- 0.5, 92.8 +/- 1.2, and 92.0 +/- 1.4, respectively; embolism: 96.7 +/- 0.6, 88.8 +/- 1.7, and 82.9 +/- 3.5, respectively; bleeding: 98.5 +/- 0.4, 97.2 +/- 0.6, and 94.4 +/- 1.7, respectively; structural valve deterioration: 99.0 +/- 0.3, 82.8 +/- 2.2, and 62.8 +/- 5.8, respectively; and reoperation: 98.2 +/- 0.4, 79.2 +/- 2.4, and 63.4 +/- 5.3, respectively. The rate of endocarditis, structural valve degeneration, and reoperation was lower in patients 75 years of age and older compared with younger patients, whereas embolism occurred more frequently in elderly than in younger patients. Adverse events after implantation of Mitroflow aortic bioprosthesis rarely occurred during the first 5 years after valve replacement. The results of the prosthesis indicates reliable long-term morbidity rates and good durability in patients 75 years of age and older.

Experience with the Mitroflow aortic bioprosthesis

From October 1985 to May 1990, the Mitroflow bovine pericardial valve was placed in the aortic position in 168 patients (97 men, 71 women) with a mean age of 69.7 years. Eighty-nine patients had isolated aortic valve replacement, and 79 had aortic valve replacement and additional procedures. Follow-up over 7½ years includes 781 patient years (426 for isolated aortic valve replacement). Mean follow-up time is 56 months. Peak-to-peak gradients (in millimeters of mercury) measured in the intraoperative period averaged 11.0 ± 8.7, 11.8 ± 10.8, and 8.6 ± 8.2 for 19 mm, 21 mm, and 23 mm valves, respectively. Hospital mortality was 7.3% (14 patients); all deaths were non-valve related. Late mortality of 20.1% in 31 patients resulted from cardiac failure ( n = 8), sepsis ( n = 4), valve reoperation ( n = 1), non-cardiac causes ( n = 15) and sudden, unknown causes ( n = 3). Fifteen thromboembolic episodes occurred, but only three late thromboembolic episodes occurred in isolated aortic valve replacement without other risk factors. Four early and four late episodes of endocarditis occurred. Seven patients had clinical valve dysfunction, and five others required reoperation for structural deterioration, with one death. At 94 months, overall survival was 64% ± 5%. Freedom from thromboembolic episode was 87% ± 3% and 90% ± 4% for isolated aortic valve replacement. Freedom from combined reoperation or clinical dysfunction was 75% ± 8%: 64% ± 15% for those under 70 years of age, and 87% ± 7% for those 70 years of age and older. The valve has favorable hemodynamics. Durability begins to decline during the sixth year after implantation, possibly at a slower rate in patients older than 70 years of age. (J THORAC CARDIOVASC SURG 1994;108:215-20)