Mitroflow pericardial valve prosthesis in the aortic position: an analysis of long-term outcome and prognostic factors

BACKGROUND AND AIM OF THE STUDY: Pericardial valves combine optimal hemodynamic properties with limited durability. To describe the long-term performance of Mitroflow pericardial valves in the aortic position, outcome and risk factors up to 12 years after implantation were analyzed. METHODS: A retrospective study, based on follow up of 1,029 patients who received 1,044 Mitroflow pericardial valves in the aortic position between February 1985 and December 1996, was performed. Follow up was 98.2% complete. Average follow up was 3.79 years. Mean patient age was 75.2+/-6.5 years (range: 27.9-90.9 years). At surgery, 86.3% of patients were aged over 70 years. Among patients, 482 (46.8%) had concomitant operations. RESULTS: Results (+/- SE) are given for evident and possible (in parentheses) valve-related events; the latter included all reported postoperative strokes and sudden deaths. Actuarial event-free rates after 5 and 10 years respectively were: structural valve deterioration: 99.2+/-0.5% and 77.6+/-4.4%; non-structural valve deterioration: 99.7+/-0.2% and 99.7+/-1.2%; valve-related complications: 95.7+/-0.9% and 73.5+/-4.0% (5 years 90.1+/-1.2%, 10 years 57.0+/-4.3%); endocarditis: 96.6+/-0.8% and 92.6+/-1.6%; explantation: 98.6+/-0.5% and 80.1+/-3.9%; cerebrovascular accident 95.2+/-0.9% and 82.5+/-3.5%; embolism 99.9+/-0.1% and 99.9+/-0.5%; bleeding 99.8+/-0.2% and 99.8+/-1.3%; overall mortality 69.9+/-1.8% and 35.3+/-3.0%; valve-related death 97.5 +/-1.1% and 95.1+/-4.2% (5 years 91.9+/-1.4%, 10 years 76.1+/-3.2%). The 30-day mortality rate was 4.1%. Patients aged 70 years or more with valve diameters of < or =23 mm showed 10-year freedom rates of 85.8+/-4.6% for structural valve degeneration and 95.1+/-1.2% for evident valve-related death. The detailed risk factor analysis showed results that were in accordance with clinical experience. CONCLUSION: Long-term results with Mitroflow pericardial valves in the aortic position compare well with those for other widely used bioprostheses, especially in patients aged > or =70 years and with small aortic root diameters (< or =23 mm).     

Mode of failure of the Mitroflow pericardial valve.

A consecutive series of 188 Mitroflow pericardial bioprostheses were inserted in 166 patients between 1st January 1983 and 31st December 1985. Twenty-two valves had to be removed from 16 patients after a mean follow up period of 78 months (range 58-92 months) for aortic, 73 months (65-79 months) for mitral and 78 months (48-103 months) for double valve replacements. All but one reoperations for primary tissue failure were carried out as elective surgical procedures. The most important cause of failure was collagen degeneration, seen in all explanted valves. The areas of degeneration were the major sites of origin of calcification, which was seen in 11 valves (50%). Ten valves (45%) showed features suggestive of lipid infiltration, extensive fatty acid deposition being identified in one and a typical atheromatous reaction in another. In contrast to the Ionescu-Shiley valve, the mode of failure was tear originating at the top of the commissure, associated with major structural changes in the tissue. Excessive pannus ingrowth was observed in 11 valves (50%). The universal presence of tissue degeneration in the glutaraldehyde treated pericardial leaflets of the Mitroflow bioprostheses explanted and examined in this study questions the adequacy of the methods employed in the harvesting and/or processing and/or preservation of this valve. We have, therefore, discontinued using the Mitroflow bioprosthesis. However, the slow deterioration of the Mitroflow bioprosthesis permits elective reoperation; preventive removal of functioning valves is therefore not indicated.     

Performance of the Ionescu-Shiley pericardial valve in the aortic position: 100 months clinical experience

From August 1977 through August 1984, 239 patients underwent aortic valve replacement (AVR) with the Ionescu-Shiley pericardial valve. Isolated AVR was performed in 112 patients and associated cardiac surgery in 127 patients (53.1%). One hundred twenty-eight patients were males and 111 females, with an average age of 50.6 years (range 15 to 78 years). There were 24 hospital deaths (10%) and 15 late deaths (8.9%). The expected 100 months survival rate was 82.8 +/- 5.5 (91.3 +/- 5.6% for isolated AVR, and 75 +/- 7.8% for associated AVR). All patients were postoperatively studied until December 1985. The cumulative duration of follow-up was 894.08 patient-years, with a mean follow-up of 44.9 months per patient. There were 10 thromboembolic episodes in this series (3 peripheral and 7 central), with a linearized incidence of 1.1% per patient-year. The actuarial projection of freedom from thromboembolic episodes at 100 months follow-up was 94.4 +/- 3.4% (96.9 +/- 2.2% for isolated AVR, and 92.6 +/- 3.9% for associated AVR). Twenty-five patients required reoperation (2.79% per patient-year): 6 for infective endocarditis, 3 for paravalvular leak, one for valve thrombosis, 3 for another valve explantation, and 12 for primary tissue failure (1.3% per patient-year). In conclusion, the Ionescu-Shiley valve has a satisfactory performance in the aortic position at long-term follow-up. In our experience, the higher rate of postoperative complications occurred among patients with concomitant cardiac surgery, so not necessarily related to this pericardial valve.     

Left ventricular mass regression after aortic valve replacement with the new Mitroflow 12A pericardial bioprosthesis

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the durability of the new Mitroflow 12A pericardial bioprosthesis and to assess ventricular mass regression after aortic valve replacement (AVR) in patients with small valves. METHODS: A total of 326 Mitroflow 12A pericardial bioprostheses was implanted without any other associated valve procedure. The mean patient age was 73.5 +/- 6.1 years; 252 patients (78.0%) were in NYHA class III/IV. Small valves (19 and 21 mm) were implanted in 212 patients (65.6%). The total follow up period was 837.1 patient-years (pt-yr). A subset of 61 patients with preoperative stenosis was selected and submitted to conventional echo-Doppler assessment at a mean period of 11.1 months after surgery. RESULTS: Hospital mortality was 8.6%. At eight years of follow up, survival was 57.1%. Freedom from structural valve deterioration (SVD) was 86.5% per pt-yr. Mean gradients were significantly reduced postoperatively for each valve size (to 18 +/- 8 mmHg for 19-mm valves and 12 +/- 4 mmHg for 25-mm valves). The effective orifice area (EOA) was also increased significantly for all valve sizes (to 1.1 +/- 0.1 cm2 for 19-mm valves and 1.8 +/- 0.2 cm2 for 25-mm valves). The left ventricular mass index (LVMI) decreased significantly, from 177 +/- 29 to 136 +/- 22 g/m2 for the 19-mm valve, and from 200 +/- 42 to 132 +/- 22 g/m2 for the 25-mm valve. The EOA index (EOAI) showed mismatch for the 19- and 21-mm valves (0.74 and 0.82 cm2/m2, respectively). The diagrammatic calculation between LVMI and relative wall thickness after surgery showed that 29.7% of patients achieved a normal pattern of remodeling (including 19- and 21-mm valves), despite various degrees of mismatch. CONCLUSION: The new Mitroflow 12A pericardial bioprosthesis showed an absence of mechanical failure after an eight-year follow up, with a satisfactory rate of SVD. Significant reductions in LVMI and improved ventricular geometry were observed, despite the small valve sizes implanted.     

Mid-term hemodynamic and clinical results of the stented porcine medtronic mosaic valve in aortic position

BACKGROUND: Our study aim was to evaluate the hemodynamic and clinical performance of the Mosaic bioprosthesis in aortic position. METHODS: The stented porcine bioprosthesis combines zero pressure glutaraldehyde fixation and amino oleic acid antimineralization treatment for improved hemodynamics and durability. Between 2/1994 and 5/1999, 100 patients underwent aortic valve replacement. Mean age at implant was 73.4 years. Patients were followed up within thirty days after intervention, after six months and then annually. Mean follow-up was 4.8 years (range 0.1-8.8 years), totaling 483.4 patient-years. RESULTS: Mortality within 30 days was 3.0 %; late mortality was 4.6%/patient-year, including 0.4 %/patient-year prosthesis-related mortality. Freedom from event rates at 8.5 years were 96.8% for thromboembolism, 97.7% for thrombosed bioprosthesis, 97.4% for structural deterioration, 98.7% for nonstructural dysfunction, 95.9 % for hemorrhage, 98.9% for endocarditis and 95.1 % for reoperation and explant. Mean pressure gradients were 15.2 mm Hg (21), 14.5 mm Hg (23), 12.7 mm Hg (25) and 13.0 mm Hg (27) after one year; effective orifice areas 1.36 cm2 (21), 1.68 cm2 (23), 1.76 cm2 (25) and 2.57 cm2 (27). CONCLUSIONS: Clinical and hemodynamic performance of the Mosaic bioprosthesis was highly satisfactory during the first 8.5 years after clinical introduction.     

Long-term results after aortic valve replacement with four different prostheses

The long-term results after implantation of isolated aortic ball and disc prostheses were studied. The Starr-Edwards ball valve type 1200 was first used in 80 patients, thereafter type 2300 was used in 173, later the Björk-Shiley and the Lillehei-Kaster disc valves were implanted in 99 and 97 patients according to randomization. The surviving patients with the oldest ball valve were examined after 4.7 and 6.7 years on an average, the others after approximately 2.5 and 4.5 years.The early mortality rate was 15%, and did not differ between the four groups. Even the late mortality rate was quite similar in the patient groups, the five-year survival rate being 65% in patients with ball valves and 68% in those with disc valves, as estimated with the actuarial method.The average reduction of heart size was moderate and quite similar in the four groups, most pronounced in patients with isolated aortic valve involvement. The reduction was greater in patients who received larger rather than smaller valves of all types.Aortic valve replacement resulted in a considerable clinical improvement in patients with all valve types; it corresponded largely to one functional group according to the NYHA classification. The heart size reduction and functional improvement was most moderate in patients with smaller ball valves, which could be anticipated from higher peak systolic gradients than across the other valves used. No significant differences appeared between patients with the larger valves of the four types.The initial improvement, as recorded either by reduction of heart size or increase in functional capacity, had reached its maximum at the first follow-up examination in most patients.The preoperative myocardial function appeared to be the limiting factor which determined what late results could be obtained regardless of the type of valve implanted. The results therefore indicate that more can be achieved by earlier valve replacement than by improving the prostheses.     

The long-term follow up results of Kay-Shiley heart valve prostheses

Three hundred and thirty six Kay-Shiley disc valves were implanted in 323 cases from 1968 to 1975 at the Hacettepe University Hospital, Ankara. Eight patients died during surgery. Of the 328 valve replacements followed postoperatively, 263 were in the mitral (80.2%), 26 in the aortic (8%) and 39 in the tricuspid position (11.9%). Three hundred and fifteen patients were evaluated in the early and late postoperative periods. In the early period 52 patients died (16.5%). The remaining cases were followed up for 1-16 years (3381 patient-years). Twenty eight patients remain alive at the time of this report (10.6%). The longest survivors are 2 of the mitral valve replacement cases. The actuarial survival estimates were 88 +/- 2.4% at 1 year, 60.3 +/- 3.4% at 5 years, 36.3 +/- 3.9% at 10 years for all cases. The incidence of thromboemboli was 4.2% per patient-year in the late period in both the overall and the isolated MVR groups. Valve failure due to thromboses was detected in 8 patients (3%). Six patients were reoperated on in the late period (2.3%).     

Doppler-catheter discrepancies in patients with bileaflet mechanical prostheses or bioprostheses in the aortic valve position

The aims of the present study were to investigate in vivo Doppler-catheter discrepancies in aortic bileaflet mechanical and stented biologic valves and evaluate whether these can be predicted using Doppler echocardiography. Results of in vitro studies of bileaflet mechanical valves suggested overestimation using Doppler gradients. Findings in stented biologic valves were conflicting. Patients who underwent valve replacement with a St. Jude Medical mechanical (n = 14, size 19 to 29) or a St. Jude Medical Biocor (Biocor, n = 13, size 21 to 25) valve were included. Simultaneous continuous Doppler recordings (transesophageal transducer) and left ventricular and aortic pressure measurements were performed using high-fidelity catheters. Gradients after pressure recovery were predicted from Doppler using a validated equation. Doppler overestimated catheter gradients in both the mechanical and Biocor. Mean Doppler catheter differences for the mechanical/Biocor were for mean gradients of 4 +/- 3 (SD; p = 0.002)/6 +/- 4 mm Hg (p = 0.002). There was a strong relation between catheter and Doppler gradients (r = 0.85 to 0.92). Doppler catheter discrepancy as a percentage of the Doppler mean gradient for the mechanical was median 41% (range -30% to 76%) and for the Biocor was median 35% (range -7% to 75%). The catheter-Doppler discrepancy was not significant using the predicted net gradient from Doppler. In conclusion, this was the first in vivo investigation of prosthetic valves using simultaneous Doppler and high-fidelity catheters. Doppler overestimated catheter gradients in both mechanical and stented biologic valves. However, the discrepancy can be predicted considering pressure recovery in the aorta.     

Durability of glutaraldehyde-fixed pericardial valve prostheses: clinical and animal experimental studies.

Bovine pericardium has been widely employed as a xenograft tissue for the manufacture of bioprosthetic valve substitutes. Early three-leaflet valve models showed poor tissue preservation and shortcomings in valve design, which accounted for tissue wear and prosthesis failure due to cuspal tear. Reducing the number of cusps in the unicusp pericardial valve has proved unsuccessful due to stretching of the single pericardial leaflet with consequent valvular incompetence. The new generation of pericardial xenografts present basic changes in valve design and optimal tissue preservation after industrial processing, with no evidence of leaflet tear at medium term follow up. However, clinical experience is limited and, similarly to porcine xenografts, dystrophic calcification still appears to be a major problem.     

Bicuspid aortic valve replacement with stentless autologous pericardial valve

Bicuspid aortic valve is a common congenital cardiac anomaly that poses a surgical challenge in young patients. We describe replacement of a bicuspid aortic valve with a stentless glutaraldehyde-treated autologous pericardial prosthesis in a 16-year-old girl.     

Ten year clinical evaluation of Starr-Edwards 2400 and 1260 aortic valve prostheses

The long term performance characteristics of the 2400 and 1260 series of Starr-Edwards aortic prostheses were investigated by a follow up study of clinical outcome of 327 patients discharged from hospital with isolated aortic valve replacement. Follow up lasted for up to 10 years and was based on 1616 patient-years. The 2400 series cloth covered tracked valve was implanted in 182 patients from 1974 to 1980 and the 1260 series bare strut silastic ball valve was inserted in 145 patients from 1979 to 1983. Total 10 year mortality and valve related morbidity were low and no cases of mechanical valve failure were recorded. There were no significant actuarial differences in mortality or valve related morbidity between the 2400 and 1260 valves. Starr-Edwards models 2400 and 1260 aortic valve prostheses showed excellent durability without any mechanical failures over a 10 year period. The long term outcome of isolated aortic valve replacement with these models is associated with a low frequency of valve related complications.     

The Freedom SOLO valve: superior hemodynamic results with a new stentless pericardial valve for aortic valve replacement

BACKGROUND AND AIM OF THE STUDY: The new Freedom SOLO aortic valve, as a modification of the Pericarbon Freedom stentless valve, requires only one suture line. The study aim was to compare both prostheses with regard to surgical convenience and early postoperative hemodynamics. METHODS: In this case-matched study, 90 patients underwent primary elective isolated or combined aortic valve replacement (AVR) between 2001 and 2004. The Freedom SOLO valve was implanted in 30 patients using a supra-annular, subcoronary technique with one continuous subcoronary suture line (group FS). For comparison, the Pericarbon Freedom valve was implanted in 30 patients using an interrupted suture (group PFI), and in 30 patients using a continuous suture line at the inflow site (group PFC). Patient hemodynamics at discharge were investigated by monitoring echocardiographic peak and mean gradients, and regurgitation. RESULTS: The mean extracorporeal circulation time (75.5+/-22.7 min in FS; 83.7+/-21.0 min in PFC versus 110.9+/-31.4 min in PFI) and cross-clamp time (56.0+/-18.6 min in FS; 62.2+/-16.2 min in PFC versus 87.7 +/-25.4 min in PFI) were significantly shorter with the continuous implantation techniques. Hemodynamics were most favorable for the Freedom SOLO valve as compared to either implantation technique of the Pericarbon Freedom valve (mean gradient 7.4+/-4.6 mmHg in FS versus 10.6+/-6.0 mmHg in PFC and 11.0+/-5.7 mmHg in PFI). There were no paravalvular leakages or transvalvular regurgitations. CONCLUSION: The Freedom SOLO stentless valve is easy to implant and demonstrates superior early postoperative hemodynamics. Due to the reduced cross-clamp time, it also offers an attractive option in isolated and combined AVR.     

Echocardiographic imaging of stentless aortic valve prostheses

Homografts and stentless xenografts are increasingly used in aortic valve surgery. Echocardiography technicians and cardiologists have to know what they will find when performing an echo-Doppler examination in patients who received a stentless valve. We therefore evaluated echocardiographic images of 74 patients who received a Freestyle stentless bioprosthesis with three techniques and a follow-up of 2 years in two high-volume hospitals. Of the patients studied, 81% were operated using the subcoronary technique, 12% using the root-inclusion technique, and 7% using the full-root technique. Results: Transvalvular gradients across the stentless valves were low: 8.0 mmHg when implanted with the subcoronary technique, 8.2 +/- 5.1 mmHg using the root-inclusion technique, and 6.5 mmHg using the full-root technique. Trivial aortic insufficiency (grade 1) was observed in 10.7% of the patients (8.9% for the subcoronary technique, 13% for the root-inclusion technique, and 0% for the full-root technique). When the bioprosthesis was implanted using the subcoronary technique or the root-inclusion technique, the prosthesis was placed inside the recipient aortic root. Using these techniques, a lumen between the double layer of the xenograft and the aortic wall could be observed. With the root-replacement technique, the porcine root became the most proximal part of the ascending aorta. As the native aortic wall was removed, in most cases, no double lumen could be observed with imaging of the ascending aorta.     

The stentless quadrileaflet bovine pericardial mitral valve: early clinical results

BACKGROUND AND AIMS OF THE STUDY: Although bioprosthetic valves currently in use have low thrombogenicity, durability remains very unsatisfactory. Valve failure occurs early from calcification, and later from tissue wear. Stentless design lessens the latter, and anticalcification treatments the former. Recently, a stentless chordally supported quadrileaflet mitral valve (QMV) bioprosthesis made of selected tanned bovine pericardium, treated to minimize calcification, has become available for clinical study. The aim of this study was to report the early results relating to valve performance, and patient outcome. METHODS: Since December 1996, the QMV has been implanted in 23 patients (mean age 38 +/- 12 years) requiring isolated mitral valve replacement for valve lesions not suited for repair. All patients were symptomatic (three in NYHA functional class II, 16 in class III, four in class IV). Preoperatively, all underwent full clinical and echocardiographic assessment, and intraoperative transesophageal evaluation immediately after valve implantation. Blood tests for hemolysis were performed preoperatively and at 3 months after surgery. RESULTS: After a mean follow up of 8.3 months (range: 1 to 18 months), 22 patients were alive and symptomatically improved (NYHA class I or II). One patient died of sternal sepsis soon after surgery. There have been no reoperations, nor cases of infective endocarditis or thromboembolism. Subclinical hemolysis was shown pre- and postoperatively in 35% and 32% of cases, respectively. Intraoperative transesophageal echocardiography post valve implantation demonstrated mitral regurgitation which was trivial in 15 patients (78%) and mild in five (22%). CONCLUSIONS: The QMV can be implanted safely, and the early clinical results relating to patient outcome and valve performance are encouraging.     

Clinical results and in vivo valve function after implantation of a Bicer valve prosthesis in the aortic position

Between December 1981 and June 1987, 71 patients underwent aortic valve replacement with a Bicer monostrut tilting disc prosthesis. Clinical results and in vivo function of the artificial valve were assessed. The average age of the 71 patients at the time of operation was 51.3 +/- 11.5 years. The hospital mortality rate was 2.8% (two patients) and there were no further deaths during a mean (+/- SD) follow-up period of 2.4 +/- 1.6 years (range 1 month to 5.5 years) after surgery. There was also no occurrence of thromboembolism or valve dysfunction. Function of the Bicer valve prosthesis was assessed in 17 patients: 5 with a 21 mm valve, 7 with a 23 mm valve and 5 with a 25 mm valve. Examination was performed on average 10.3 +/- 8.1 months after surgery. Valve function was examined at rest and during exercise performed with a bicycle ergometer. Pressure gradients at rest were low: 21 mm valve = 8 mm Hg, 23 mm valve = 3 mm Hg and 25 mm valve = 2 mm Hg; the gradients during exercise were 11, 8 and 8 mm Hg, respectively. The valves had the following effective orifice area at rest: 21 mm valve = 1.54 cm2, 23 mm valve = 4.20 cm2 and 25 mm valve = 3.76 cm2; during exercise, the respective areas were 1.57, 3.48 and 3.01 cm2. These valves are deemed to be sufficiently wide for effective valve function. Aortographic observation indicated mild regurgitation that was within reasonable limits and posed no problem.(ABSTRACT TRUNCATED AT 250 WORDS)