Mitroflow Pericardial Bioprosthesis Research Articles

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

BackgroundLimited 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. MethodsNine 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. ResultsExplants, 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. ConclusionsCollagen 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.

The relation of structural valve deterioration to adverse remodelling and outcome in patients with biological heart valve prostheses.

Native valve aortic stenosis is associated with adverse remodelling of the left ventricle and remodelling is stopped or even reversed with aortic valve replacement (AVR). However, the degeneration of bioprostheses and development of structural valve deterioration (SVD) may affect this. To assess the association with SVD, remodelling and outcome 451 patients from a single surgical centre who had undergone AVR with a Mitroflow pericardial bioprosthesis were studied. All patients were assessed in 2014 and a subgroup of patients (N = 327) were re-exanimated again after at least 18 months [median time of 27 (interquartile range, IQR 26-33) months] including echocardiography, measurements of N-terminal pro-brain natriuretic peptide, and assessment of functional status. SVD was based on echocardiography. Moderate SVD was present in 63 patients (14%) and severe SVD in 19 (4%), in the subgroup with follow-up echocardiography 48 patients (15%) patients had moderate to severe SVD at first examination. Patients with SVD had significantly greater increase in left ventricular (LV) mass index [21.6 g/m2 (IQR 5.7-48.3 g/m2) vs. 9.1 g/m2 (-8.6 to 27.3 g/m2), P = 0.01]. Further, patients with SVD had lower LV ejection fraction [55% (IQR 51-62%) vs. 60% (IQR 54-63%), P = 0.01] at follow-up. During follow-up, 94 patients (21%) met the composite endpoint of death or reoperation due to SVD and 41 patient readmitted for heart failure. In multivariable Cox regression analysis, severe SVD [hazard ratio (HR) 2.64 (1.37-5.07), P = 0.004] was associated with composite endpoint, and readmission for heart failure [HR 3.82 (1.53-9.51), P = 0.004]. SVD in aortic bioprostheses is associated with adverse LV remodelling and adverse outcome.

Durability of the Mitroflow Pericardial Prosthesis: Influence of Patient-Prosthesis Mismatch and New Anticalcification Treatment.

The Mitroflow pericardial bioprosthesis (MPB) has been recently associated with a high incidence of early structural failures, questioning its validity as cardiac valve substitute. We have therefore reviewed our experience with this device. A total of 398 patients with a mean age of 75 ± 7 years (58% above the age of 75 years) had aortic valve replacement with a Mitroflow prosthesis (2005-2015). Most patients had calcific aortic stenosis (86%) and were in sinus rhythm (89%). Mean EuroSCORE II was 5.5 ± 6.2. Mean follow-up was 4 ± 2 years (range: 4 months to 10 years), which was 100% complete. Hospital mortality was 6.5%; at discharge, 25% of patients had a moderate patient-prosthesis mismatch and none had a severe mismatch. Cumulative incidence of structural valve deterioration in the entire series was 2% (95% confidence interval [CI]: 1-4) at 5 years and 7% (95% CI: 4-14) at 8 years. Significant factors influencing MPB durability were age ≤ 65 years (p < 0.001) and the presence of patient-prosthesis mismatch (p = 0.01). No cases of structural valve deterioration were observed in patients with the new prosthetic model incorporating an anticalcification treatment the first 4 years of follow-up. The Mitroflow prosthesis has shown satisfactory results in the first decade of use. Durability appears adversely influenced by patient age and patient-prosthesis mismatch. Thus, a careful valve size selection and implantation in patients >65 years of age appears to be associated with excellent valve durability in the aortic position. Whether the new anticalcification treatment will provide a more durable prosthesis must be verified at a longer follow-up.

Corrigendum to: The Italian study on the Mitroflow postoperative results (ISTHMUS): a 20-year, multicentre evaluation of Mitroflow pericardial bioprosthesis [Eur J Cardiothorac Surg 2011;39:18-26

Corrigendum to: The Italian study on the Mitroflow postoperative results (ISTHMUS): a 20-year, multicentre evaluation of Mitroflow pericardial bioprosthesis [Eur J Cardiothorac Surg 2011;39:18-26

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

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. 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. 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. 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.

Mitroflow pericardial bioprosthesis: structured failure at 4.5 years

Prosthetic heart valves are commonly used in the management of significant valvular disease. Although bioprostheses are increasingly popular, structural deterioration with cusp tears and calcification persists. We present a case of a Mitroflow pericardial bioprosthesis (Sorin Group Inc., Mitroflow Division, Vancouver, Canada) explanted after 4.5 years from a 78-year-old woman for bioprosthesis stenosis. The morphological reasons for bioprosthesis failure include structural tissue deterioration with thickening of the pericardial cusps, cusp calcification, and parastent post tears resulting in significant valvular dysfunction. To the best of our knowledge, this is the first detailed morphological description of the failure modes of a surgically explanted Mitroflow (A12) pericardial bioprosthesis.

Is distortion of the bioprosthesis ring a risk factor for early calcification?

BackgroundAs the population ages, bioprosthesis are increasingly being used in cardiac valve replacement. Pericardial bioprosthesis combine an excellent hemodynamic performance with low thrombogenicity, but valve failure associated with calcification remains a concern with these valves. We describe distortion of the bioprosthesis ring as a risk factor for early calcification.MethodsA total of 510 patients over the age of 70 years underwent isolated aortic valve replacement with the Mitroflow (A12) pericardial bioprosthesis. Thirty two patients (6,2%) have undergone a second aortic valve replacement due to structural valve dysfunction resulting from valve calcification. In all patients a chest radiography and coronary angiography was performed before reoperation. A 64 Multidetector Computed Tomography (MDCT) with retrospective ECG gating study was performed in four patients to evaluate the aortic bioprosthesis.ResultsChest radiography showed in all patients an irregular bioprosthesis ring. At preoperative coronary angiography a distorted bioprosthesis ring was detected in all patients. Macroscopic findings of the explanted bioprostheses included extensive calcification in all specimens.ConclusionThere was a possible relationship between early bioprosthetic calcification and radiologic distortion of the bioprosthesis ring.

Mitroflow pericardial aortic bioprosthesis in patients younger than 60 years

Mitroflow pericardial aortic bioprosthesis in patients younger than 60 years

The Italian study on the Mitroflow postoperative results (ISTHMUS): a 20-year, multicentre evaluation of Mitroflow pericardial bioprosthesis☆

A multicentre experience with the Mitroflow pericardial bioprosthesis has been evaluated longitudinally over a 20-year period. From 1988 through 2008, 1591 patients (mean age, 75.3±6.8 years, and 60.1% female) from 12 centres had a Mitroflow in the aortic position. Concomitant coronary artery bypass was performed in 41.9% (n=666) of patients, urgency/emergency surgery in 9.5% (n=152) and replacement of degenerated prosthesis in 2.3% (n=36). Follow-up (7.447 patient-years) was 99.2% complete. Median follow-up was 61.9 months (interquartile range (IQR) 30.8-90.9 months). The study was carried out following American Association for Thoracic Surgery/Society for Thoracic Surgeons/European Association for Cardio-Thoracic Surgery (AATS/STS/EACTS) Guidelines for reporting valve morbidity and mortality. The early (30-day) mortality was 6.5% (n=104). Actuarial survival rates at 10, 15 and 18 years were 53%, 34% and 27%, respectively (2.2 patient/year). Re-operation was required in 96 patients (5.9%), of whom 59 patients (3.7%) for structural valve degeneration. Actuarial freedom from prosthetic valve degeneration at 18 years was 65.5% (78% in patients>70 years) with a linearised rate of 1.4 patient/year (0.8 patient/year in patients>70 years). At 18 years, freedom from embolism was 82% (0.9 patient/year), freedom from valve endocarditis was 89% (0.6 patient/year) and freedom from bleeding episodes was 95% (0.2 patient/year), respectively. This independent multicentre study indicates that the Mitroflow pericardial bioprosthesis provides favourable long-term postoperative results with a low rate of valve-related events and need of re-intervention, particularly in patients older than 70 years.

Early calcification of the aortic Mitroflow pericardial bioprosthesis in the elderly

We report our experience in the elderly with aortic valve replacement using the Mitroflow A12 pericardial bioprosthesis. From January 1993 to January 2006, 491 patients over the age of 70 years received an aortic Mitroflow A12 bioprosthesis implantation. Concomitant procedures included coronary artery bypass grafting in 20% of patients. All patients had routine postoperative Echo-Doppler studies at discharge, one month and a mean of 11.1 months after surgery and annually thereafter. Twenty (4%) patients underwent a second aortic valve replacement due to bioprosthetic valve dysfunction (Group 2). Calcified stenosis was the most common finding at reoperation (98%). Median time to valve reoperation was 76 months. Of patients requiring reoperation, median age at first and second implantation was 73 (70-78) and 79 (76-83) years, respectively. For all patients, freedom from structural valve dysfunction (SVD) was 95+/-3% at 5 years and 55.8+/-2% at 10 years. Bioprosthetic valve deterioration was identified in 27 patients (Group 1). Median age of these patients at first operation and at diagnosis of deterioration by echo was 75 (70-84) and 77 (70-82) years, respectively. The median interval between operation and detection of bioprosthesis valve deterioration was 46 months. Among the total patient population, freedom from bioprosthetic deterioration was 85.7+/-2% at 5 years and 33.5+/-4% at 10 years. The Mitroflow A12 pericardial bioprosthesis provides less than optimal performance in elderly patients.

Aortic valve replacement with the Mitroflow pericardial bioprosthesis: Durability results up to 21 years

Aortic valve replacement with the Mitroflow pericardial bioprosthesis: Durability results up to 21 years

Aortic valve replacement with the Mitroflow pericardial bioprosthesis: Durability results up to 21 years

The study aim was to analyze the performance profile of a large series of Mitroflow pericardial valves (Sorin Group Canada Inc. Mitroflow Division) in the very long term. Data from 1513 patients with isolated aortic valve replacement who received pericardial bioprostheses between 1986 and 2007 were analyzed. Cumulative duration of follow-up was 6164 patient-years with a maximum duration of 21 years. Actuarial rates of valve-related events were calculated by the Kaplan-Meier method and the Cox multivariate analysis to identify independent determinants of outcome. Hospital mortality for elective surgery was 2.5%. Late death was 40.6%. Reoperation was required in 86 (5.7%) patients and was valve related in 83: structural valve deterioration in 64 (4.2%) patients, prosthetic valve endocarditis in 17 patients (1.1%), valve thrombosis in 1, and periprosthetic leak in 1. Rates of 20-year actuarial freedom from valve-related morbidity were as follows: structural valve deterioration 84.8% (actual 96.6%) in patients 70 years of age or older; thromboembolism 94.1%; and prosthetic valve endocarditis 96.8%. Twenty-year actual risk of reoperation for structural valve deterioration was 11.4% in all patients and 3.4%, in patients 70 years or age or older. Advanced age, renal insufficiency, pulmonary disease, and low body mass index were independent risk factors for late outcome (P < .001). After 2 decades of follow-up, the Mitroflow pericardial aortic valve continues to be a valve of choice with a predictable low rate of valve-related events, particularly for patients over the age of 65 to 70 years and others with comorbidities.

CarboMedics Mitroflow Pericardial Aortic Bioprosthesis - Performance in Patients Aged 60 Years and Older after 15 Years

The purpose of this study was to carry out a current assessment of the Mitroflow pericardial bioprosthesis (model 11) according to the durability of the prosthesis after 15 years in patients aged 60 years or older. This bioprosthesis was implanted in 161 patients (mean age 69.5 +/- 6.3 years; range 60 - 94 years) undergoing aortic valve replacement (AVR) between 1982 and 1992. There were 84 patients aged 60 - 69 years (mean 64.5 +/- 3.1years) and 77 patients aged 70 years or older (mean 74.8 +/- 4.3 years). Of the total population, concomitant procedures were performed in 63 patients (39.1 %); of these, coronary artery bypass grafting was performed in 39 (24.2 %). Early mortality was 4.8 % (4 patients) in the 60 - 69 year age group and 10.4 % (8) in patients aged 70 years or older ( P = 0.290). Late mortality was 4.5 %/patient-year (35) for those aged 60 - 69 years and 8.1 %/patient-year (49) for those aged 70 years or older ( P = 0.007). Patient survival at 15 years of patients aged 60 - 69 years was 47.6 +/- 6.3 % and of patients aged 70 years or older was 20.9 +/- 5.4 % ( P = 0.003) ( ). Freedom from valve-related mortality for patients in the 60 - 69 year age group was 92.1 +/- 3.5 % at 15 years (0.6 %/patient-year [5]), and in the patient group aged 70 years or older it was 84.4 +/- 5.3 % (1.3 %/patient-year [8]; P = 0.194). Freedom from reoperation for patients in the 60 - 69 year age group was 73.9 +/- 5.0 % (2.6 %/patient-year [20]), and for patients aged 70 years or older it was 91.4 +/- 3.4 % (1.0 %/patient-year [6]; P = 0.029). The structural valve deterioration (SVD) rate for patients in the 60 - 69 year age group was 2.4 %/patient-year (19), and for patients aged 70 years or older it was 1.0 %/patient-year (6) ( P = 0.041). Actuarial freedom from structural valve deterioration at 15 years for patients aged 60 - 69 years was 62.0 +/- 7.3 %, and 80.8 +/- 7.9 % for patients aged 70 years and older ( P = 0.049) (actual freedom 73.9 +/- 5.2 % and 91.4 +/- 3.4 %, respectively). The Mitroflow pericardial bioprosthesis can still be recommended for aortic valve replacement in patients 70 years and older.

Transesophageal echocardiography of a new paravalvular echolucent area after aortic valve replacement

THIS CASE INVOLVES a 73-year-old man with severe aortic stenosis who was scheduled for aortic valve replacement. The patient had a 2-year history of exertional angina, occasional presyncopal episodes, shortness of breath on exertion, and orthopnea. He also had non-insulin-dependent diabetes mellitus and hyperlipidemia. His medications included atenolol, entrophen, and simvastatine. Preoperative transthoracic echocardiographic (TTE) assessment revealed severe aortic stenosis with an aortic valve area of 0.6 cm2 and a mean pressure gradient of 59 mmHg. Severe left ventricular dilatation with trivial mitral regurgitation and an ejection fraction of 35% were also noted. Coronary angiography was normal except for a 50% stenosis of the second diagonal artery.

Mitroflow Pericardial Bioprosthesis in the Aortic Position: Low Incidence of Structural Valve Deterioration in Elderly Patients during an 11-Year Follow-up

Aortic valve replacement with Mitroflow pericardial bioprosthesis, with or without concomitant bypass surgery was performed on 403 consecutive patients between March 1984 and December 1994. The mean age was 74 (range 10-92) years, with male/female ratio 183/220. Early mortality was 3.5% (14/403) and late mortality 25% (99/389). Actuarial survival was 35.4%+/-9.4% at 10 years and freedom from valve-related mortality 86.2%+/-9.6% at 8 years (total follow-up 1 270 years). The thromboembolic rate was 6.5% (fatal 0.7%)/patient year. The incidence of prosthetic valve endocarditis was 0.6% (fatal 0.3%)/patient year. Structural valve deterioration was found in 0.8%/patient year (no fatality). Actuarial freedom from all reoperations at 8 years was 92.4+/-8%. The Mitroflow pericardial heart valve is proposed as a good choice for aortic valve replacement in elderly patients, in view of the low rates of reoperation, anticoagulant treatment and valve-related thromboembolism.

Mitroflow pericardial bioprosthesis experience in aortic valve replacement ≥60 years of age

Background. The Mitroflow pericardial bioprosthesis (model 11), a second-generation pericardial prosthesis, has clinical performance assessment to 10 years. The authors previously recommended the prosthesis for aortic valve replacement in patients 70 years or older. The purpose of the current assessment is to report on performance in patients 60 years or older undergoing aortic valve replacement. Methods. This bioprosthesis was implanted in 161 patients (mean age, 69.5 ± 6.3 years; range, 60 to 94 years) with aortic valve replacement from 1982 to 1992. There were 84 patients 60 to 69 years (mean, 64.5 ± 3.1 years) and 77 patients 70 years or older (mean, 74.8 ± 4.3 years). Of the total population, concomitant procedures were performed in 63 patients (39.1%); of these, coronary artery bypass grafting was performed in 39 (24.2%). Results. The early mortality was 4.8% (4 patients) for the 60 to 69-year age group and 10.4% (8) for those 70 years or older (not significant). The late mortality was 4.4%/patient-year (27) for those 60 to 69 years and 6.9%/patient-year (35) for those 70 years or older (not significant). The patient survival for those 60 to 69 years was 58.0% ± 6.3% and for those 70 years or older, 45.3% ± 5.9% at 10 years ( p < 0.05). The valve-related mortality for those 60 to 69 years was 0.82%/patient-year (5) and for those 70 years or older, 1.58%/patient-year (8) (not significant). The reoperation rate for those 60 to 69 years was 3.29%/patient-year (20) and for those 70 years or older, 1.0%/patient-year (5) ( p < 0.05). The structural valve deterioration rate for those 60 to 69 years was 3.13%/patient-year (19) and for those 70 years or older, 1.2%/patient-year (6) ( p < 0.05). Conclusions. The Mitroflow pericardial bioprosthesis remains recommended for aortic valve replacement in patients 70 years and older.

Mitroflow pericardial bioprosthesis: Clinical performance to ten years

The Mitroflow pericardial bioprothesis, a second generation pericardial prosthesis, has clinical performance assessment to 10 years. This bioprosthesis was used in 445 operations in 445 patients between 1982 and 1992 inclusive (mean age, 59.1 years; age range, 19 to 94 years). There were 253 aortic valve replacements (AVR), 155 mitral valve replacements (MVR), 31 multiple valve replacements (MR), and 6 tricuspid valve replacements. Concomitant procedures were performed in 40 patients (14.2%). The age group distributions (years) were less than or equal to 35 years, 28 patients; 36 to 50 years, 79; 51 to 64 years, 167; 65 to 69 years, 70; and 70 years or more, 101 patients. The total follow-up was 1,524 patient-years (mean, 5.4 years), 96% complete. The early mortality was 6.3%/patient-year (28 patients) and the late mortality was 4.1%/patient-year (96 patients). Concomitant procedures did not influence either early or late mortality (p = not significant [NS]). The overall patient survival at 10 years was 58% +/- 5% (p = NS by valve position). The overall freedom from structural valve deterioration (SVD) at 8 years was 69% +/- 3% and at 10 years, 45% +/- 7%; and at 8 years AVR 80% +/- 4%, MVR 58% +/- 6%, and MR 38% +/- 11% (p < 0.05, AVR > MVR > MR). The freedom from thromboembolism (TE) was 87% +/- 2%, overall at 10 years, and was not different by valve position (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Mitroflow Pericardial Bioprosthesis: Experience to Seven Years

Between 1983 and 1987, the Mitroflow pericardial prosthesis was implanted in 99 patients, ranging in age from 28 to 94 years (mean 62.8 years). Early mortality was 6.1% (6 patients), and late mortality was 4.8% per patient-year (22 patients). Total cumulative follow-up was 458 patient-years (mean 4.6 years). At 7 years, patient survival was 62% for aortic valve replacement and 63% for mitral valve replacement. The overall rate of valve-related complications was 7.4% per patient-year (34 events): thromboembolism, 2.8%; antithromboembolic-relatedhemorrhage, 1.1%; prosthetic valve endocarditis, 0.7%; non-structural dysfunction, 0.7%; and structural valve deterioration, 2.8%. At 7 years, freedom from thromboembolism was 80.3%, and freedom from prosthetic valve endocarditis was 95.5%. At 5 and 7 years, freedom from structural valve deterioration was 93.4% and 69.7%, respectively. At 5 years, freedom from structural valve deterioration was 97.3% for aortic valve replacement (AVR), 86.6% for mitral valve replacement (MVR), and 100% for multiple valve replacement (MR). At 7 years, freedom from structural valve replacement was 84.6% and 61.3% for AVR and MVR, respectively. At 7 years, overall freedom from reoperation was 68.2%; from valve-related mortality, 81.4%; from valve-related residual morbidity, 97.4%; and from treatment failure (valve-related mortality and residual morbidity), 79.0%. At 7 years, the Mitroflow pericardial bioprosthesis has provided satisfactory clinical performance, especially in the aortic position, with an acceptable freedom from structural valve deterioration.

The mitral medical pericardial bioprosthesis: new generation bovine pericardial prosthesis.

The Mitral Medical Mitroflow pericardial bioprosthesis was implanted in 99 operations (99 patients with 104 valves) between 1984 and 1987. The mean age of the patients was 62.8 years (range 28 to 94 years). The early mortality was 6.1% (including patients with concomitant procedures--coronary artery bypass and ascending aortic aneurysm resection). Late mortality was 2.3% per patient-year. The total cumulative follow-up was 172 years. Thromboembolism (TE) was 4.1% per patient-year (fatal 1.2% per patient-year) (minor 2.3%; major 1.8%); antithromboembolic therapy-related hemorrhage (ATH) 0.6% (fatal 0.6%); prosthetic valve endocarditis (PVE) 0.6% (fatal 0%); periprosthetic leak (PPL) 0.6% (fatal 0%); clinical valve dysfunction (CVD) 1.2% (fatal 0%); and structural valve deterioration/primary tissue failure (SVD) 1.2% per patient-year (fatal 0% per patient-year). Thromboembolism was the significant complication. SVD occurred in two patients during the third year of evaluation. The overall patient survival was 89.2 +/- 3.3% at four years. The patients were classified as 91.9% NYHA functional Class III and IV preoperatively and 97.7% Class I and II postoperatively. The freedom at four years from TE was 88.5% +/- 4.9%; SVD 92.5 +/- 5.1%; and reoperation 89.8% +/- 5.3%. Freedom from all valve-related complications at four years was 76.8% +/- 6.6%; valve-related mortality 97.2 +/- 2.0%; mortality and reoperation (valve failure) 87.3% +/- 5.5%; mortality and residual morbidity (treatment failure) 95.5% +/- 2.6%; and mortality, residual morbidity, and reoperation (valve failure and dysfunction) 85.6% +/- 5.7%. There were three valve-related deaths of a total of ten deaths (early 2; late 1) (TE 2; ATH 1; CVD 0; PVE 0; PPL 0; and SVD 0). Valve-related reoperation was performed in four patients (TE 0; CVD 0; PVE 1; PPL 1; and SVD 2). The Mitral Medical Mitroflow pericardial bioprosthesis has provided very satisfactory clinical performance and afforded patients excellent quality of life.