Choice of heart valve prosthesis.
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Age Factors↗
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Results for “HEART VALVE PROSTHESIS”
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THE DESIGN AND DEVELOPMENT OF A CARDIAC SIMULATOR FOR THE EVALUATION OF HEART-VALVE PROSTHESIS.
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Cardiac Surgical Procedures↗
[Heart valve prosthesis from autologous pericardium. Preliminary results apropos of 15 patients].
The concept of a heart valve prosthesis made from autologous pericardium is based on the idea of creating and developing a valve with a longer life than heterografts or homografts due to the absence of tissue degeneration causing the deterioration of both of these types of bioprostheses. The first attempts using the fascia lata or the pericardium, implanted in the seventies, were unsuccessful due to problems with pretreatment of the pericardium and other purely technical difficulties. J. Love et al then developed a technique based on Carpentier's earlier work, where a valve is made extemporaneously using the autologous pericardium. We applied this technique in 14 patients from June 1994 to 1995. The mean age of the patients was 68 years (7 males, 7 females). The aortic valve was replaced in all cases. Preoperative findings were: aortic stenosis (n = 7), aortic regurgitation (n = 1), aortic valve disease (n = 6). Two patients also had mitral valve disease and 3 had coronary artery disease. There were no operative deaths and no patients were lost to follow up. Clinical state was satisfactory with a follow-up of 1 to 10 months. Postoperative Doppler echocardiography was performed at 3 and 6 months and showed gradients were very low. This group of patients demonstrated the value and applicability of the concept. The validity of the technique will be evaluated as a function of the long-term results.
Adult↗
[Perioperative management for hemicolectomy using propofol infusion in an elderly patient with a mechanical heart valve prosthesis].
An 81-year-old female (145 cm, 39 kg) with a mechanical heart valve prosthesis underwent right hemicolectomy for cecal cancer under total intravenous anesthesia. She had received anticoagulation therapy [international normalized ratio (INR) 4.3] with warfarin for two years before surgery due to replaced aortic valve and atrial fibrillation. Three days before surgery warfarin was switched to heparin infusion (400 U.h-1) continued until 3 hours before the surgery. The activated partial thromboplastin time (APTT) was maintained above 1.5 times of the control (45 sec). Before induction of anesthesia, the activated clotting time (ACT) was 166 seconds. Following propofol infusion (50 ml.h-1; 38 mg) and vecuronium, anesthesia was maintained with propofol infusion (5.9 mg.kg-1.h-1), buprenorphine i.v. (0.08 mg) and appropriate doses of vecuronium. The total dose of propofol used was 950 mg. Heparin infusion (80 U.h-1) was restarted at the onset of surgery. Intraoperative ACT levels were between 148 and 156 seconds. However, at the end of surgery, APTT was prolonged (60.7 sec). Heparin infusion was reduced to 40 U.h-1 and APTT became normal 3 hours after the surgery. On the 4th postoperative day, heparin infusion was returned to 400 U.h-1 (APTT 32-38 sec). Two days after warfarin restoration on the 15th postoperative day, heparin was discontinued (INR 2.1-2.5). The thromboembolism and bleeding tendency did not occur. This case suggests that despite the suspected bleeding tendency via platelet inhibition under propofol infusion, the reduced heparin infusion can be continued with close coagulation monitoring.
Aged↗
Midterm evaluation of the Sorin Bicarbon heart valve prosthesis: single-center experience.
BACKGROUND: The purpose of this study was to perform midterm evaluation of the clinical performance of the Sorin Bicarbon mechanical heart valve prosthesis. METHODS: From November 1992 to December 2002, 328 patients underwent isolated aortic (AVR; 156) or mitral (MVR; 172) valve replacement with the Sorin Bicarbon mechanical valve. Concomitant surgery was performed in 83 patients (25.2%). RESULTS: Total hospital mortality was 5.2%. Survival at 7 years was 79.5% for AVR and 82.4% for MVR. Kaplan-Meier freedoms from valve-related complications were as follows: thromboembolism 92.7% (AVR 94.8%, MVR 92.1%); bleeding 93% (AVR 91.9%, MVR 94.5%); nonstructural dysfunction 96.6% (AVR 94.7%; MVR 97.9%); endocarditis 97.7% (AVR 97.4%, MVR 98.1%); and reoperation 95.7% (AVR 96.6%, MVR 93.9%). Overall freedom from valve-related death was 93.2% (AVR 99.3%, MVR 91.2%). At the end of follow-up, 88.9% of survivors were in New York Heart Association class I or II. CONCLUSIONS: The Sorin Bicarbon valve is a satisfactory mechanical valve prosthesis with low mortality and morbidity and good functional results.
Actuarial Analysis↗
Forty-year survival with the Starr-Edwards heart valve prosthesis.
BACKGROUND AND AIM OF THE STUDY: The study aim was to update an analysis of the long-term survival of heart valve replacement using the Starr-Edwards prosthesis. METHODS: Cases of isolated aortic (AVR, n = 2,247) and mitral (MVR, n = 1,406) valve replacement with Starr-Edwards prostheses implanted between 1960 and 1997, with follow up to 2003, were reviewed. Introduced in 1965, the Models A1200/1260, M6120 are still in use (Current), while other models have been discontinued (Discontinued). For AVR, 938 valves were Discontinued, with a total follow up of 8,506 patient-years (pt-yr) and a maximum of 41 years; by comparison, 1,309 valves were Current, with a total follow up of 11,586 pt-yr and a maximum of 36.1 MVR, were Discontinued, with a total follow up of 6,454 pt-yr and maximum of 37.2 years; and 771 valves were Current, with a total follow up of 6,211 pt-yr and maximum of 37.0 years. RESULTS: Kaplan-Meier (KM) survival at 10 years was 53% for AVR and 51% for MVR; KM survival at 20 years was 23% for both AVR and MVR; KM survival at 30 years was 8% for both AVR and MVR; KM survival at 40 years was 4% for AVR. The standard error for all KM percentages was 1%. Four patients are currently alive with their original valves, more than 40 years after implantation. CONCLUSION: This series of patients, who underwent valve replacement with the Starr-Edwards valve, now have a follow up extending beyond 40 years, thereby confirming the excellent durability of this valve.
Actuarial Analysis↗
[Permanent heart valve prosthesis: half a century of search].
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Animals↗
Determination of markers of coagulation activation and reactive fibrinolysis in patients with mechanical heart valve prosthesis at different intensities of oral anticoagulation.
In a group of 60 patients with mechanical heart valve prosthesis prothrombin fragment 1 + 2, thrombin-antithrombin III complexes and D-dimer have been determined in order to assess the residual coagulation activation and the extent of the reactive fibrinolysis. The patients were divided into three subgroups of 20 patients each with different intensities of oral anticoagulation as indicated by International Normalized Ratio (INR) values in the ranges 4.8-3.6, 3.5-2.5 and 2.4-2.1. From the two markers of coagulation activation studied (prothrombin fragment 1 + 2 and thrombin-antithrombin III (TAT)) the prothrombin fragment 1 + 2 was dependent on the INR level in all groups, although the median values were still significantly beneath the lower limit of the reference range. The D-dimer concentrations were unexpectedly high with respect to the low coagulation activation levels, as indicated by the D-dimer/TAT and D-dimer/F 1 + 2 ratios. This demonstrates the enhanced presence of fibrin degradation products as a scarcely described side-effect of oral anticoagulation. The anticoagulant properties of fibrin degradation products might contribute partly to the in vivo haemorrhagic risk in high-intensity oral anticoagulation. These results show, inasmuch as the prothrombin fragment 1 + 2 is concerned, that from the laboratory point of view the residual thrombin activity is low enough to be adequate under the therapeutical regimen followed in this study. However, the question of the efficacy of anticoagulation intensities can only be finally answered by clinical trials.
Administration, Oral↗
Experimental evaluation of the mitroflow pericardial heart valve prosthesis. Part I. In vivo hemodynamic evaluation.
Evaluation of possible enhanced durability of the Mitroflow pericardial heart valve prosthesis was undertaken in an experimental animal model using the Chacma baboon. For comparison purposes a small series of 4 Ionescu-Shiley pericardial valves were also implanted. The 33 Mitroflow prostheses implanted were all manufacturer's size 21mm and belonged to 4 different groups according to the process used for the preparation of the pericardium (Process I to IV). The Ionescu-Shiley prostheses were all manufacturer's size 19mm and were commercially available valves. The valves were implanted in the mitral position, except one each Mitroflow and Ionescu-Shiley prosthesis that was implanted in the tricuspid position. Four animals died in the early postoperative period, between 2 and 14 days. Two died from a probable viral infection, one from a low cardiac output state and the fourth one from bacterial endocarditis. The clinical evaluation of the animals for an implantation time of up to twelve months was unremarkable. Hemodynamic studies were performed immediately after implantation (n = 29), at an intermediate cardiac catheterization at 9 months after implantation (n = 4) and at the time of terminal elective sacrifice of the animals (n = 33). From the data obtained the resultant prosthetic valve area at the time of elective sacrifice of the animals was also calculated. The data obtained for each of the 5 groups of valves tested are presented in the text. Transvalvular gradients measured at the time of sacrifice of the animals were elevated.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Thrombosis of mechanical heart valve prosthesis. Predisposing factors and results of surgical treatment].
Heart valve thrombosis is a serious complication. From February, 1995 to January, 1996, 19 patients were studied to identify predisposing factors and results of surgical management. Mean age was 47.3 years. Thirteen patients (73.6%) had an irregular surveillance of anticoagulation therapy. Fifteen patients showed low anticoagulation effect during their evolution. Sixteen patients were in functional class III and 80% (15 patients) showed imaging of thrombus in the echocardiographic study. All patients presented thrombus on both sides of the prothesis. There were no deaths, and 15 patients returned to functional class I. It was concluded that the main predisposing factor in this series of patients was deficient anticoagulation therapy, and surgical results are comparable to those other authors.
Adult↗
[Reoperation because of mechanical heart valve prosthesis dysfunction].
Thromboembolism, haemolysis, prosthetic endocarditis and paravalvular leakage are the commonest complications of introduction of mechanical heart valve prosthesis. Malfunction of the cusps inside the sewing ring is a rare but serious condition, which is due to partial or total prevention of the free movements of the cusps or valves resulting in symptoms of valvular stenosis or incompetence. Twenty-six valvular prosthesis (2.3%) were replaced on account of malfunction. Fifteen out of the 26 patients were submitted to emergency operation and 11 to elective intervention. Four out of the 26 patients died preoperatively or during the postoperative course, corresponding to a lethality of 15%. The operative lethality was associated with emergency operations exclusively. The authors conclude that patients with previously well functioning valvular prosthesis who develop symptoms of cardiac failure should be referred to the cardiological centre where the operation was carried out as rapidly as possible instead of institution of traditional medical treatment.
Adult↗
[Pathomechanism of failure of the Cross-Jones heart valve prosthesis].
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Heart Valve Prosthesis↗
Dynamics of a mechanical monoleaflet heart valve prosthesis in the closing phase: effect of squeeze film.
An analysis of the dynamics of a mechanical monoleaflet heart valve prosthesis in the closing phase is presented. The backflow velocity of the fluid and the pressure distribution on the occluder during the closing phase were computed using a control volume approach in the unsteady state. Using moment equilibrium principles on the occluder motion and the squeeze film dynamics of the fluid between the occluder and the guiding strut at the instant of impact, the velocity of the occluder tip and the impact force between the occluder and the guiding struts were computed. The dynamics of fluid being squeezed between the occluder and the guiding struts are accounted for by Reynolds' equation. The effect of the fluid being squeezed between the occluder and the guiding strut was to reduce the velocity of the occluder tip at the instant of valve closure as well as to dampen the fluttering of the occluder before coming to rest in the fully closed position. The squeeze film fluid pressure changed rapidly from a high positive value (10 MPa) to a relatively large negative value (-15 MPa) in < 1 msec. The results of this study may be extended for the analysis of cavitation inception and mechanical stresses on the formed elements and valve components, as well as to estimate the endurance limits of prosthetic valves.
Biomechanical Phenomena↗
Clinical evaluation of the St. Jude Medical heart valve prosthesis. A two-year follow-up of 150 patients.
To evaluate the clinical performance of the St Jude Medical bileaflet heart valve prosthesis, we followed 150 consecutive patients (95 male and 55 female patients, mean age 54 years, range 1 to 74 years) for an average of 24 months. These included 74 patients with aortic, 56 patients with mitral, and 20 patients with multiple valve replacement. During the 2 year follow-up, there were a total of four perioperative and seven late deaths, two of which were prosthesis related. Reoperation was necessary in four patients, because of paravalvular leaks in two patients with mitral and one patient with aortic prostheses and because of leaflet dislodgment in one patient with a mitral prosthesis, a postoperative complication that has not been reported previously. The thromboembolic rate per 100 patient-years was 2.6 in aortic and 2.9 in mitral valve replacement, the symptoms being reversible in all patients. All patients were receiving anticoagulant therapy. A total of four complications of anticoagulant therapy (three minor and one fatal) were observed. Significant hemolysis was observed in none of the patients. In patients with dyspnea, the New York Heart Association functional classification was 2.7 +/- 0.8 preoperatively versus 1.3 +/- 0.6 postoperatively. In patients with angina, it was 2.6 +/- 0.6 preoperatively versus 1.03 +/- 0.2 postoperatively. Noninvasive Doppler measurements revealed excellent flow characteristics, values being close to those obtained in natural valves (mean +/- standard deviation of maximal flow velocity: 1.5 +/- 0.5 versus 0.9 +/- 0.1 m/sec in the aortic position; 1.1 +/- 0.3 versus 0.8 +/- 0.3 m/sec in the mitral position).
Adolescent↗
Pregnancy and successful delivery in a patient with triple heart valve prosthesis.
A 42-year-old patient had a history of rheumatic fever in childhood. At 37 years of age, she underwent a triple heart valve replacement; thereafter, she was followed with the administration of warfarin and methyldigoxin. Her third pregnancy occurred with the last menstruation on 12 March 1990. At the 30th gestational week, she was admitted to the Nagoya University Hospital for the control of anticoagulation and rest. She delivered by cesarean section a healthy male infant weighing 2070 g at 34 weeks of gestation. The post-operative course was uneventful. This report shows that a patient with a three heart valve prosthesis tolerated pregnancy well under intense medical supervision.
Adult↗
Thrombotic and hemorrhagic complications in patients with mechanical heart valve prosthesis attending an anticoagulation clinic.
This study evaluated the advantage of an anticoagulation clinic in terms of the improvement of the clinical quality of oral anticoagulation (i.e. prevention of thromboembolism and low rate of hemorrhagic complications). The incidence of thromboembolic events and major hemorrhagic complications was assessed in a series of 271 patients on oral anticoagulation for mechanical heart valve prosthesis before and after their enrollment in our anticoagulation clinic from January 1987 to December 1990. Risk factors for hemostatic events were also analyzed. The incidence of major hemostatic complications was significantly lower when patients attended the clinic: 1.0 vs 4.9%/pt-yr for hemorrhage and 0.6 vs 6.6%/pt-yr for thrombosis. This depended on three main factors: better dose regulation of warfarin, continuous patient education and early identification of clinical conditions potentially at risk for thrombosis and hemorrhage. Only previous hemorrhagic or thromboembolic events were recognized as major risk factors for hemostatic complications. In conclusion, our study shows that an anticoagulation clinic offers a real advantage to patients with mechanical heart valve prosthesis in terms of prevention of thromboembolic events and hemorrhagic complications.
Administration, Oral↗
In vitro function and durability assessment of a novel polyurethane heart valve prosthesis.
While flexible-leaflet, central-flow prosthetic heart valves promise relief from anticoagulation therapy, they continue to be restricted by inadequate durability. In consequence, a novel trileaflet valve, made entirely from polyurethane, has been developed. A batch of 6 consecutively manufactured polyurethane valves was subjected to hydrodynamic function and accelerated fatigue testing. Computerized data acquisition and control systems have been introduced to improve valve testing methodologies. In terms of hydrodynamic function, the polyurethane valve demonstrates transvalvular pressure gradients similar to those for a bioprosthetic valve (Carpentier-Edwards) and levels of retrograde flow significantly less than those for either the bioprosthetic valve or a bileaflet mechanical valve (St Jude Medical). The equivalent of 10 years of cycling without failure has been exceeded by all 6 polyurethane valves in accelerated fatigue tests with 2 valves remaining intact after 674 million cycles (equivalent to approximately 17 years) in continuing tests. Highspeed photography revealed considerable differences in leaflet motion between valves cycled at accelerated and physiological rates.
Biocompatible Materials↗