Two years' experience with the duromedics bileaflet heart valve prosthesis

The new Duromedics Bileaflet Cardiac Valve prosthesis has a special moving hinge mechanism for its two leaflets to wash the critical articulation area and thus reduce thrombus formation. Between October 1983 and June 1985, we implanted 278 of these prostheses in 254 patients. We did 114 aortic valve replacements, 109 mitral valve replacements, 34 double valve replacements, and two tricuspid valve replacements. Nearly 20% of the patients had had previous cardiac procedures. The hospital mortality was 5.9%. Follow-up was started with 214 surviving Austrian patients, and up to the present time, we have a follow-up period of 1704 patient months. Five patients died late after the operation (3.5 per 100 patient years). We observed 10 valve-related complications in nine patients (7 per 100 patient years). There were three cases of prosthetic endocarditis (2.1 per 100 patient years), two paravalvular leaks, and four bleeding episodes (2.8 per 100 patient years). The mechanical hemolysis was minimal, and the postoperative hemoglobin value averaged 15 g%. The LDH increased from 230 IU to 307 in the aortic valve replacements, 406 in the mitral valve replacements, and 435 in the double valve replacements. Intraoperative pressure gradients and postoperative Doppler echocardiography showed good hemodynamic performance. We conclude that good clinical results and a low complication rate can be achieved with the Duromedics Valve.     

Twelve years' experience with Carbomedics bileaflet valves

The authors report long-term results of a cohort of patients who underwent valve replacement with a Carbomedics bileaflet mechanical prosthesis. The influence of patient age on the results was examined. Three hundred and ninety patients were operated between 1988 and 2000. Complete follow-up was available in 98.5% of cases. For aortic valve replacement, the total experience was 1,061 person-years. The hospital mortality was 2.3%. Global actuarial 12 year survival was 74 +/- 7%. The actuarial probability of absence of thrombo-embolic complications at 12 years was 95 +/- 3%, and of absence of haemorrhagic complications 89 +/- 4%. For mitral valve replacement, the total experience was 610 person-years. The hospital mortality was 3.4%. The global actuarial 12 year survival was 78 +/- 5%. The actuarial probability of absence of thrombo-embolic complications at 12 years was 79 +/- 9% and of absence of haemorrhagic complications 82 +/- 5%. The results of survival and prosthesis-related complications were comparable to those reported in the literature with second generation mechanical prostheses, with the exception of thromboses of the mitral valve for which a higher linear rate was observed. Multivariate analysis showed an increased (x 2.3) risk of haemorrhage after 60 years of age irrespective of the site of implantation of the prosthesis. In patients over 60 years of age, the risks of long-term anticoagulant therapy should raise questions concerning the modality of follow-up and the indications. The use of biological prostheses is a possible alternative.     

Reintervention on valve prosthesis. 13 years' experience

1584 valve prosthesis implants [1231 mechanical (MP) and 353 biological (BP)] were carried out personally between March 1974 and December 1986. Over the same period, 72 patients, 36 m and 26 f, average age 48, underwent 75 reintervention (RI) on 80 malfunctioning prostheses 41 MP, 39 BP, 41 in mitral position, 28 aortic, 1 tricuspid). The reasons for RI in the MP were: partial detachment (61%), infectious endocarditis (19.5%), mechanical dysfunction (14.7%), thrombosis (2.4%), wear (2.4%) and in the BP: wear (84.6%), infectious endocarditis (12.8%), partial detachment (2.6%). The malfunction was diagnosed before the onset of subjective symptomatology in 30.7% of patients. Operative mortality (OM) was 17.3% related to the functional class (II = 0%; III = 2.7%; IV = 38.7%) and to whether or not the intervention was an emergency or of choice (90.9% and 4.7% respectively). Mortality was higher in patients operated on for infectious endocarditis (38.4%) and in wearers of MP (28.2% vs. 5.7% BP); however this difference is largely attributable to a difference in NYHA class. It is concluded that reintervention on valvular prosthesis may have a very prognosis provided diagnosis of malfunction is quick enough to avoid excessive functional deterioration.     

Mid-term results after heart valve replacement with the CarboMedics bileaflet prosthesis: experience with 785 implants.

BACKGROUND: The aim of the study was to evaluate our clinical experience with the CarboMedics Heart Valve Prosthesis. METHODS: Between October 1991 and December 1997, six hundred seventy-two consecutive patients (361 men, 54%; 311 women, 46%; mean age 57 +/- 12 year, range 6-73 years) underwent mechanical valve implantation at the Division of Cardiac Surgery of the University of Verona. Preoperatively, 69% of the patients were in NYHA FC III or IV. Eighty-one patients (12%) had undergone a previous cardiac operation and 14.5% had an ejection fraction less than 35%. We performed an aortic valve replacement in 309 patients (78 valved-conduits for replacement of the entire aortic root), a mitral valve replacement in 250, and a double valve in 113. 52 patients (8%) underwent associated myocardial revascularization. RESULTS: Early mortality was 2.8% (5/309 aortic, 1.6%; 11/250 mitral, 4.4%; 3/113 double, 2.6%). Late mortality was 4.4%. Actuarial survival at 5 years was 89.3% (aortic, 91.1%, mitral 86.4%, double 90.5%). Thromboembolism occurred in 26 patients (3.9%) and major hemorrhagic events in 20 (3%). Nine patients (1.3%) required a reoperation, in 3 cases (0.4%) after endocarditis (Staphylococcus epidermidis). No structural deterioration occurred in our series. CONCLUSION: Our study appears to confirm the safety and reliability of the CarboMedics mechanical valve prosthesis, even in old age groups. This bileaflet prosthesis demonstrates no structural deterioration, a low incidence of complications, and good hemodynamic performance.     

Seven and one-half years' experience with the Medtronic-Hall valve

The Medtronic-Hall valve was developed to improve on existing tilting disc valves by reducing the risk of valvular thrombosis. This was to be accomplished by improving the hemodynamics and by allowing the disc to move downstream away from the orifice during opening. The valve was also designed for maximal structural durability to minimize the risk of mechanical breakage. With more than 1,000 Medtronic-Hall valves implanted since 1977, the clinical results have been very encouraging. The rates of thromboembolism and thrombosis are low, there have been no mechanical failures and the hemodynamic function, especially with the smaller valves, is excellent.     

The worldwide mid-term experience with the Medtronic ADVANTAGE bileaflet mechanical heart valve

BACKGROUND AND AIM OF THE STUDY: A total of 639 patients (479 men, 160 women; mean age 60 +/- 10 years) underwent isolated aortic valve replacement (AVR) between 25 November 1999 and 20 October 2003, using the Medtronic ADVANTAGE bileaflet mechanical heart valve. The study aim was to quantify the clinical performance of a valve with two design modifications: (i) an enlarged central orifice intended to improve blood flow characteristics; and (ii) an asymmetric butterfly pivot recess with expanded outflow component designed to enhance the washing of blood flow through the pivot region. METHODS: Patients were enrolled at 21 centers located in Europe, Canada, Australia, and the USA. The study was conducted under the authority of regional ethics committees, as well as the respective national regulatory agencies. All centers adhered to a common protocol. RESULTS: The total follow up was 1,215.9 patient-years. The average systolic mean pressure gradient across the prosthesis was < 10 mmHg. The mean left ventricular mass index decreased by 22.87 g/m2 (13% reduction) over 12 months. The numbers of valve-related intraoperative, early (< or = 30 days or prior to discharge) and late (> or = 31 days) deaths were 0, 10 and 19, respectively. After one year and four years of follow up, 99.3% (n = 560) and 100% of patients (n = 37), respectively, were in NYHA class I or II. CONCLUSION: The evolutionary bileaflet design of the ADVANTAGE valve achieved the desired clinical functionality and performance.     

Fatal hemolysis due to unidentified causes following mitral valve replacement with bileaflet tilting disc valve prosthesis

Summary Fatal hemolysis after mitral valve replacement with the St. Jude bileaflet tilting prosthesis is reported in two patients. Although one underwent re-replacement of the valve, both died from multiple organ failure and acute renal failure, respectively. Scanning electron microscopy revealed microthrombi adherent to a leaflet in one and irregular leaflet surfaces in the other. Such defects are rare but are possible causes of hemolysis in patients with the St. Jude mitral valve prosthesis.     

Fifteen years' clinical experience with the CarboMedics prosthetic heart valve

BACKGROUND AND AIM OF THE STUDY: The CarboMedics bileaflet prosthetic heart valve was first implanted as part of a prospective clinical study at the authors' institution in November 1987. The patient cohort included was part of a multicenter trial set up by the manufacturer for an FDA application. The present report details findings over a 15-year period, with a continuous follow up on this patient cohort. METHODS: Between November 1987 and August 1990, 132 patients (68 males, 64 females; median age 56 years; range: 12-74 years) received a CarboMedics heart valve prosthesis. All patients were included in the study, whether surgery was elective or emergency, first time or reoperation. There were 69 aortic, 49 mitral and 12 double (aortic and mitral) valve replacements. Two patients had isolated tricuspid valve replacement. Concomitant surgery was performed in 15 patients. Anticoagulation with warfarin was started on postoperative day 1. After discharge, patients were examined regularly as outpatients for up to five years. Subsequent follow up was obtained prospectively by questionnaires to the patients' general practitioners and with telephone calls to the patients. Actuarial estimates of survival and freedom from morbid events were calculated using the Kaplan-Meier method; 95% confidence limits for the distribution function were calculated according to the Greenwood formula. RESULTS: Complete follow up information was available on 94% of the patients; total follow up was 1,270.3 patient-years (pt-yr). Actuarial survival at 15 years was 51+/-4.9% overall; 56+/-6.2% for single aortic, 51+/-8.0% for single mitral, and 30+/-15.9% for double valve replacements. Actuarial rates of freedom from complications were: valve thrombosis 100%, embolism 89+/-3.3%, and all anticoagulant-related bleeding 76+/-4.5%. The linearized rates per 100 pt-yr were: embolism 0.94 (aortic 0.74, mitral 1.25); anticoagulant-related bleeding 2.28; paravalvular leakage overall 0.24 (aortic 0.29); prosthetic valve endocarditis overall 0.24 (aortic 0.29, mitral 0.21). There was no hemolysis, prosthetic valve dysfunction, or structural deterioration. CONCLUSION: Over a 15-year time frame, the CarboMedics prosthetic heart valve has proven to be a highly reliable device with no structural failures and a low incidence of valve-related complications.     

Fourteen years' experience with the CarboMedics valve in young adults with aortic valve disease

BACKGROUND AND AIM OF THE STUDY: Homografts and the Ross procedure are recommended by many surgeons for aortic valve replacement (AVR) in young adults. The study aim was to monitor patient outcome over a 14-year period after implanting mechanical CarboMedics prosthetic heart valves in young adults with aortic valve disease. METHODS: Between November 1987 and December 2000, 55 patients (42 males, 13 females; median age 33 years; range 15-40 years) each received a CarboMedics valve in the aortic position. All patients were included on a consecutive and non-selected basis. Concomitant surgery was performed in five patients. Anticoagulation was commenced on postoperative day 1. After discharge, patients were followed up by their cardiologist or general practitioner using questionnaires and telephone calls. Actuarial estimates of survival and freedom from morbid events were calculated using the Kaplan-Meier method. RESULTS: No patient died during surgery. Complete follow up data were available for all patients; total follow up was 404 patient-years (pt-yr). The 30-day mortality rate was zero. Actuarial survival at 14 years was 90 +/- 4.9%, and actuarial freedom from all valve-related events 92 +/- 3.7%. No valve thrombosis or major bleeding events were identified. Linearized rates per 100 pt-yr were: embolism 0.25; paravalvular leakage 0.25; prosthetic endocarditis 0.25; and reoperation 0.50. There was no hemolysis, prosthetic valve dysfunction, or structural deterioration. CONCLUSION: Over a 14-year period, implantation of the CarboMedics prosthetic heart valve has proven to be an excellent solution for AVR in young adults with aortic valve disease.     

Twelve years' clinical experience with the CarboMedics prosthetic heart valve

BACKGROUND AND AIM OF THE STUDY: The CarboMedics bileaflet prosthetic heart valve was first implanted as part of a prospective clinical study at the authors' institution in November 1987. The patient cohort included was part of a multicenter trial set up by the manufacturer for an FDA application. The present report details findings over a 12-year period, with a continuous follow up on this patient cohort. METHODS: Between November 1987 and August 1990, 132 patients (68 males, 64 females; median age 56 years; range 12-74 years) received a CarboMedics heart valve prosthesis. All patients were included in the study, whether surgery was elective or emergency, first time or reoperation. There were 69 aortic, 49 mitral and 12 double (aortic + mitral) valve replacements. Two patients had isolated tricuspid valve replacement. Concomitant surgery was performed in 15 patients. Anticoagulation with warfarin was started on postoperative day 1. After discharge, patients were examined regularly as outpatients for up to five years. Subsequent follow up was obtained prospectively by questionnaires to the patients' general practitioner, or by telephone calls. Actuarial estimates of survival and freedom from morbid events were calculated using the Kaplan-Meier method; 95% confidence limits for the distribution function were calculated according to the Greenwood formula. RESULTS: Complete follow up information was available for 94% of the patients; total follow up was 1,014.3 patient-years (pt-yr). Actuarial survival at 12 years was 62 +/- 0.5% overall (61 +/- 6.5% for aortic; 66 +/- 7.5% for mitral; 65 +/- 14.0% for double valve replacements). Actuarial rates of freedom from complications were: valve thrombosis 100%, embolism 92 +/- 2.8%, and anticoagulant-related bleeding 77 +/- 5.6%. The linearized rates per 100 pt-yr were: embolism 0.89 (aortic 0.74, mitral 1.30); anticoagulant-related bleeding 2.56; paravalvular leakage overall 0.20 (aortic 0.37); prosthetic valve endocarditis overall 0.20 (aortic 0.37). There was no hemolysis, prosthetic valve dysfunction or structural deterioration. CONCLUSION: Over a 12-year time frame, the CarboMedics prosthetic heart valve has proven to be a highly reliable device with no structural failures, and a low incidence of valve-related complications.     

Lower anticoagulation for mechanical heart valves: experience with the ATS bileaflet valve

Background: The design of the bileaflet ATS (ATS Medical Inc., Minneapolis, USA) mechanical valve incorporates an open pivot at the hinge mechanism. Total washout of the blood at the pivot area was observed using 3-D computational fluid dynamics modelling. This phenomenon could make the valve less vulnerable to clot formation in patients without major thromboembolic risk factors.

Methods: From January 1993 to June 1999, 286 consecutive patients had the ATS valve inserted in the aortic position. Patients were divided into two groups. Group 1 comprised all patients in regular sinus rhythm with good left ventricular function (144 patients). Group 2 included patients in non-sinus rhythm and/or with large hypocontractile left ventricles (142 patients). The anticoagulation regime in group 1 was used to obtain an international normalised ratio (INR) between 1.5 and 2.5. This contrasts with our regular aim to maintain the INR strictly between 2.5 and 3.5 for all mechanical valves, as achieved in group 2.

Results: The follow-up period (99% completeness) ranged from 18 to 84 months. Survival (Kaplan-Meier) was 97 and 98% and 92 and 81% at 1 and 5 years in group 1 and group 2, respectively (P = 0.12). Log rank analysis failed to detect a statistical difference in thromboembolism or bleeding between both groups (P > 0.05). However, trends were in favour of group 1. Univariate analysis selected poor ventricular function and an ‘erratic’ INR value (P = 0.002) as risk factors for death. The sole independent risk factor for bleeding was the use of aspirin (P = 0.025).

Conclusions: The excellent group 1 data and outcome encouraged us to continue our low intensive anticoagulation regime and perhaps should be regarded as a new concept for treatment of selected mechanical valve patients.     

6 years clinical experience with the TEKNA bivalve heart valve prosthesis

OBJECTIVE: The revised Edwards-Duromedics valve was introduced onto the market in June 1990. In September 1993, the producer changed the name of the valve to TEKNA, which is a low profile, bileaflet, mechanical prosthesis with a self-irrigating hinge mechanism. The results of a prospective follow-up study after valve replacement with this prosthesis are presented. METHODS: From November 1990 to December 1996, 173 TEKNA prostheses were implanted in 161 patients (73 men, 88 women), either in the aortic (AVR; 48.4%), mitral (MVR; 44.1%), or aortic and mitral positions (DVR; 7.5%). Patient ages ranged from 17 to 83 years (mean age 59.2 +/- 8.7 years). Follow-up was 97.5% complete, comprising 433.15 patient-years for a mean follow-up of 34.8 +/- 23 months. RESULTS: Overall operative (30-day) mortality was 4.97%. Fifteen patients died in the late period, corresponding to a linearized late mortality rate of 3.5%/pt-yr. Actuarial survival at six years was 75.3% +/- 6.2% overall. The actuarial freedom from complications was calculated as follows (linearized rates in parentheses): valve-related mortality 91.3% +/- 5.1% (0.92%/pt-yr); thromboembolism 94.2% +/- 2.5% (1.62%/pt-yr); valve thrombosis 98.6 +/- 1.0% (0.46%/pt-yr); bleeding events 85.9% +/- 4.7% (2.77%/pt-yr); prosthetic valve endocarditis 98.6 +/- 0.9% (0.46%/pt-yr); nonstructural dysfunction 93.2 +/- 3.2% (1.38%/pt-yr); reoperation 87.1 +/- 5.3% (2.08%/pt-yr). Functional class according to NYHA was improved from preoperatively 72.05% in III or IV to 6-year postoperative 94.2% in I or II. CONCLUSION: The clinical performance of the TEKNA valve is quite satisfactory, with low incidence of valve-related complications. No structural deterioration has been observed. Further, the patients physical ability and quality of life were significantly improved.