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At least 109 records · Page 6Linked to original sources
PubMed1993

A comparison of outcomes in men 11 years after heart-valve replacement with a mechanical valve or bioprosthesis. Veterans Affairs Cooperative Study on Valvular Heart Disease.

BACKGROUND: Mechanical heart valves are durable but thrombogenic, and their use requires that the patient receive anticoagulants. In contrast, bioprosthetic valves are less thrombogenic, but they have limited durability because of tissue deterioration. METHODS: To compare the outcomes of patients who receive these two types of valves, we randomly assigned 575 men scheduled to undergo aortic-valve or mitral-valve replacement to receive either a mechanical or a bioprosthetic valve. The primary end points were death from any cause and any valve-related complication. RESULTS: During an average follow-up of 11 years, there was no difference between the two groups in the probability of death from any cause (11-year probability for mechanical valves, 0.57; for bioprostheses, 0.62; P = 0.57) or in the probability of any valve-related complication (0.65 and 0.69, respectively; P = 0.39). There was a much higher rate of structural valve failure among patients who received bioprosthetic valves (11-year probability, 0.15 for the aortic valves and 0.36 for the mitral valves) than among those who received mechanical valves (no valve failures; P < 0.001). However, this difference was offset by a higher rate of bleeding complications among patients with mechanical valves than among those with bioprosthetic valves (11-year probability, 0.42 and 0.26, respectively; P < 0.001) and by a greater frequency of peri-prosthetic valvular regurgitation among patients with mechanical mitral valves than among those with mitral bioprostheses (11-year probability, 0.17 and 0.09, respectively; P = 0.05). CONCLUSIONS: After 11 years, the rates of survival and freedom from all valve-related complications were similar for patients who received mechanical heart valves and those who received bioprosthetic heart valves. However, structural failure was observed only with the bioprosthetic valves, whereas bleeding complications were more frequent among patients who received mechanical valves.

Aortic Valve↗
PubMed1983

Failure of Hancock xenograft valve: importance of valve position (4- to 9-year follow-up).

To evaluate long-term durability of Hancock valves, we reviewed our results in 107 hospital survivors (120 valves) who were operated on during 1974 through mid-1979. Mitral valve replacement was done in 63 patients, aortic valve replacement in 20, and mitral valve replacement combined with other procedures in 24. The 7-year survival was 84 +/- 4% (standard error of the mean) for 91 patients and 97 valves. During a follow-up of 590 patient-years, 15 (12 mitral and 3 aortic) of 120 valves at risk (87 mitral, 32 aortic, 1 tricuspid) were removed from 14 patients. Six valves (3 mitral and 3 aortic) were removed because of bacterial endocarditis. One mitral valve was removed because of thromboembolism. Eight mitral valves were removed because of valve structural failure, which occurred at a mean follow-up of 42 months. These valves showed extensive calcification, leaflet perforation, or cusp tear. Structural failure was unrelated to valve size, year of implantation, or valve shelf-life. Structural failure was not seen after aortic valve replacement. Results show that structural failure of the Hancock xenograft valve in the mitral position is related primarily to valve position. After aortic valve replacement, valve failure is predominantly due to endocarditis. Although medium-term (mean, 6-year) durability of this xenograft valve compares satisfactorily with prosthetic valves, its high failure rate in the mitral position indicates the necessity for improvement in valve mounting, design, and preservation.

Adolescent↗
PubMed2000

Outcomes 15 years after valve replacement with a mechanical versus a bioprosthetic valve: final report of the Veterans Affairs randomized trial.

OBJECTIVES: The goal of this study was to compare long-term survival and valve-related complications between bioprosthetic and mechanical heart valves. BACKGROUND: Different heart valves may have different patient outcomes. METHODS: Five hundred seventy-five patients undergoing single aortic valve replacement (AVR) or mitral valve replacement (MVR) at 13 VA medical centers were randomized to receive a bioprosthetic or mechanical valve. RESULTS: By survival analysis at 15 years, all-cause mortality after AVR was lower with the mechanical valve versus bioprosthesis (66% vs. 79%, p = 0.02) but not after MVR. Primary valve failure occurred mainly in patients <65 years of age (bioprosthesis vs. mechanical, 26% vs. 0%, p < 0.001 for AVR and 44% vs. 4%, p = 0.0001 for MVR), and in patients > or =65 years after AVR, primary valve failure in bioprosthesis versus mechanical valve was 9 +/- 6% versus 0%, p = 0.16. Reoperation was significantly higher for bioprosthetic AVR (p = 0.004). Bleeding occurred more frequently in patients with mechanical valve. There were no statistically significant differences for other complications, including thromboembolism and all valve-related complications between the two randomized groups. CONCLUSIONS: At 15 years, patients undergoing AVR had a better survival with a mechanical valve than with a bioprosthetic valve, largely because primary valve failure was virtually absent with mechanical valve. Primary valve failure was greater with bioprosthesis, both for AVR and MVR, and occurred at a much higher rate in those aged <65 years; in those aged > or =65 years, primary valve failure after AVR was not significantly different between bioprosthesis and mechanical valve. Reoperation was more common for AVR with bioprosthesis. Thromboembolism rates were similar in the two valve prostheses, but bleeding was more common with a mechanical valve.

Aged↗
PubMed2005

Performance of bioprostheses and mechanical prostheses assessed by composites of valve-related complications to 15 years after mitral valve replacement.

OBJECTIVE: Predominant concerns of patients undergoing valve replacement surgery are risks of death, stroke, antithrombotic bleeding, and reoperation related to the replacement prosthesis. The purpose of this study was to compare valve-related reoperation, morbidity (permanent impairment), and mortality between bioprostheses and mechanical prostheses for mitral valve replacement. METHODS: Between 1982 and 1998, a total of 959 bioprostheses were implanted in 943 patients, and a total of 961 mechanical prostheses were implanted in 839 patients. Total follow-ups were 5730 years for bioprostheses and 5271 years for mechanical prostheses. Eight variables were considered as predictors of risk for the composites of valve-related complications. RESULTS: The linearized occurrence rates for valve-related reoperation were 3.7 events/100 patient-years for bioprostheses and 0.5 events/100 patient-years for mechanical prostheses ( P < .001), with all age groups differentiated except older than 70 years. Valve-related morbidity was undifferentiated for bioprostheses and mechanical prostheses. Valve-related mortalities were 1.7 events/100 patient-years for bioprostheses and 0.7 events/100 patient-years for mechanical prostheses ( P < .001). Predictors of valve-related reoperation were age and valve type. The only predictor of valve-related morbidity was age, whereas age and valve type were predictors for valve-related mortality. Actual freedom from valve-related reoperation favored mechanical prostheses in all age groups except older than 70 years (91.7% +/- 2.0% for bioprostheses at 15 years and 96.7% +/- 1.5% at 12 years for mechanical prostheses). Actual freedom from valve-related morbidity was not different between bioprostheses and mechanical prostheses. Actual freedom from valve-related mortality favored mechanical prostheses in all groups except older than 70 years. CONCLUSION: Comparative evaluation gives high priority in mitral valve replacement for mechanical prostheses relative to bioprostheses for freedom from valve-related reoperation and valve-related mortality but not valve-related morbidity. Freedom from valve-related reoperation and valve-related mortality favors mechanical prostheses for all age groups except older than 70 years. Valve-related morbidity, due to neurologic or functional impairments, does not differentiate between bioprostheses and mechanical prostheses.

Adult↗
PubMed1983

Extension of calcific deposits in the anterior mitral valve leaflet and mitral valve stenosis severity. Use of 2D Echo parasternal long-axis view.

To evaluate the role of the extent of calcific deposits on the anterior mitral leaflet in predicting the severity of mitral valve stenosis, two-dimensional echocardiography (2D Echo) and heart catheterization data were analysed in 62 patients with mitral valve stenosis, pure or associated with trivial valve regurgitation. 50 patients had technically adequate 2D Echo. Of these, 28 had pure mitral valve stenosis. The mitral valve area was estimated from the parasternal short-axis 2D Echo projection. Using the parasternal long-axis projection, calcium deposits location and extension on the anterior mitral leaflet was examined. Patients were subdivided into the following groups: Group 0 (absence of calcium deposits = 19 patients), Group 1 (calcium on distal third of the leaflet = 19 patients), Group 2 (calcium on mid and distal segments = 11 patients), Group 3 (calcium on the entire leaflet = one patient). The extension of calcium deposits in long-axis projection was contrasted with 2D Echo mitral valve area in the 50 mitral valve patients. 2D Echo and heart catheterization derived mitral valve area were compared to each other in the 28 patients with pure mitral valve stenosis. 2D Echo mitral valve area was greater in Group 0 patients (1.8 +/- 0.4 cm2) than in Group 1 (1.4 +/- 0.4 cm2) and in Group 2 (1.1 +/- 0.3 cm2) (p less than 0.001 between the three groups). Calcific deposits were present on the anterior mitral leaflet in 30/31 patients with 2D Echo mitral valve area less than or equal to 2 cm2. However, of the 19 patients of Group 0, 13 had moderate and one severe mitral valve stenosis. In the 28 patients with pure mitral valve stenosis, 2D Echo mitral valve area was excellently correlated with Gorlin's derived mitral valve area (r = 0.90). However, in patients with extensive calcification of the anterior mitral valve leaflet (Group 2), 2D Echo mitral valve area was significantly greater than the Gorlin's derived area (1.08 +/- 0.20 cm2 versus 0.68 +/- 0.17 cm2; p less than 0.001). In four patients of Group 2, the mitral valve stenosis was moderate by 2D Echo grading and severe by heart catheterization data. Our data suggest that the study of extension of calcific deposits on the anterior mitral valve leaflet may be a complementary aid in quantifying mitral valve stenosis to the 2D Echo mitral valve area estimate, especially when the valve is severely calcified.

Calcinosis↗
PubMed1998

Valve repair versus replacement for mitral insufficiency: when is a mechanical valve still indicated?

OBJECTIVES: Although many advantages of mitral valve reconstruction have been demonstrated, whether specific subgroups of patients exist in whom mechanical valve replacement offers advantages over mitral reconstruction remains undetermined. METHODS: This study examined the late results of mitral valve surgery in patients with mitral insufficiency who received either a St. Jude Medical valve (n = 514) or a mitral valve reconstruction with ring annuloplasty (n = 725) between 1980 and 1996. RESULTS: Overall operative mortality was 7.2% in the patients receiving a St. Jude Medical mitral valve and 5.4% in those undergoing mitral valve reconstruction (no significant difference); isolated mortality was 2.5% in the St. Jude Medical group and 2.2% in the valve reconstruction group (no significant difference). The follow-up interval was more than 5 years for 340 patients with a mean of 39.8 months (98.5% complete). Overall 8-year freedom from late cardiac death, reoperation, and all valve-related complications was 72.8% for the St. Jude Medical group and 64.8% for valve reconstruction group (no significant difference). For patients with isolated, nonrheumatic mitral valve disease, 8-year freedom from late cardiac death and reoperation was better in the mitral valve reconstruction group (88.3%) than in the St. Jude Medical valve group (86.0%; p = 0.05). Furthermore, Cox proportional hazards regression revealed that mitral valve reconstruction was independently associated with a lesser incidence of late cardiac death (p = 0.04), irrespective of preoperative New York Heart Association class. However, the St. Jude Medical valve offered better 8-year freedom from late cardiac death, reoperation, and all valve-related complications than did mitral valve reconstruction in patients with multiple valve disease (77.0% vs 45.3%; p < 0.01). CONCLUSIONS: Therefore, mitral valve reconstruction appears to be the procedure of choice for isolated, nonrheumatic disease, whereas insertion of a St. Jude Medical valve should be preferred for patients with multiple valve disease.

Cardiac Surgical Procedures↗
PubMed1998

Inaccurate and misleading valve sizing: a proposed standard for valve size nomenclature.

BACKGROUND: The sizes with which manufacturers label valves are nonuniform and haphazard. This has led to confusion and inappropriate comparisons of hemodynamics between valves with the same labeled size. Hemodynamic performance of valves is primarily determined by the internal diameter (ID) of their orifice. METHODS: The purpose of this study was to determine the ID and external diameter of aortic valves used at our institution and compare the measurements to manufacturers' labeled sizes. We also evaluated valve size (ID, manufacturers' labeled size) in 527 patients undergoing isolated aortic valve replacement between 1990 and 1996. RESULTS: We demonstrated that no two manufacturers' tissue or mechanical valves have the same ID or external diameter for a given labeled size. The labeled size of tissue valves was 1 to 4 mm larger than the measured ID. The labeled size of mechanical valves was 3 to 5 mm larger than the measured ID. The St. Jude HP mechanical valve has a greater ID than all other mechanical valves for each labeled size. Among 403 patients operated on for predominant aortic stenosis, those patients receiving the Toronto Stented Porcine Valve (n = 98) had a larger mean ID (22.3+/-1.9 mm) than 204 patients receiving stented tissue valves (ID = 20.9+/-1.9 mm) and the 101 patients receiving mechanical valves (ID = 19.3+/-1.9 mm, p < 0.0001). However, when the manufacturers' labeled size was used as a measure of the size, the results were greatly exaggerated in favor of the Toronto Stented Porcine Valve (ID = 26.3+/-1.9 mm) compared with stented tissue valves (ID = 23.1+/-2.1) or mechanical valves (ID = 23.6+/-1.9) (p < 0.0001). CONCLUSIONS: Manufacturers' labeling of valves is nonuniform and may lead to erroneous comparisons and conclusions of hemodynamic differences between valves. We therefore recommend a standardized nomenclature for the size of all valves based on the ID measurement.

Aortic Valve↗
PubMed1984

Early and late risk of aortic valve replacement. A 12 year concomitant comparison of the porcine bioprosthetic and tilting disc prosthetic aortic valves.

Aortic valve replacement was performed in 912 consecutive patients from January, 1972, to January, 1983. The 616 male and 296 female patients, whose ages ranged from 16 to 95 years (mean 60.6 years and median 63 years), received 663 bioprosthetic valves and 249 tilting disc valves. A higher incidence of Functional Class IV heart disease and ascending aortic aneurysms was noted in the group receiving the tilting disc valve. Six hundred fifty-seven patients had primarily aortic stenosis and 255 had primarily aortic regurgitation. Associated procedures were done in 308 patients (33%): 233 had coronary bypass grafting, 46 had replacement of ascending aortic aneurysms, and 29 had miscellaneous procedures. The overall operative mortality was 6.4% (59/912). The operative mortality was 4.5% (29/640) for isolated aortic valve replacement, 4.2% (21/233) for valve replacement plus coronary bypass, and 17% (8/46) for valve replacement plus replacement of an ascending aortic aneurysm. The mortality was 4.2% (20/663) for the group receiving bioprostheses and 12.4% (31/249) for those receiving tilting disc valves. The operative mortality for 1983 for all aortic valve replacement procedures was 2.1%; for isolated valve replacement, 1%; for valve replacement plus coronary bypass, 4.4%; and for valve replacement plus aortic aneurysm replacement, 0%. The long-term follow-up was analyzed as of Jan. 1, 1984, so that there was a minimum follow-up of 12 months (mean 55 months and median 51 months). The actuarial survival rate at 108 months for all patients was 67% +/- 2%; for valve replacement alone, 71% +/- 3%; for valve replacement plus coronary bypass, 58% +/- 7%; for valve replacement plus ascending aortic aneurysm replacement, 45% +/- 10%; for aortic stenosis, 70% +/- 3%; for aortic regurgitation, 61% +/- 4%; for Functional Classes I to III, 77% +/- 3%; for Class IV, 53% +/- 4%; for age less than 63 years, 75% +/- 3%; and for age greater than 63 years, 57% +/- 4%. At 108 months, the probability of freedom from thromboembolism was 85% +/- 3% after bioprosthetic valve replacement and 83% +/- 3% after replacement with a tilting disc valve (p = NS). The probability of freedom from hemorrhage at 108 months was 98.6% +/- 7% for the bioprosthetic valve group and 89% +/- 2% for the tilting disc valve group (p less than 0.001). The valve thrombosis rate was 0.34% per patient-year for the tilting disc valves and 0.07% per patient-year for the bioprostheses.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1998

A comparison of the cavitation potential of prosthetic heart valves based on valve closing dynamics.

BACKGROUND AND AIMS OF THE STUDY: This study compares the cavitation potential of prosthetic heart valves based on valve closing dynamics. METHODS: A laser sweeping technique measured valve closing dynamics (average closing velocity and deceleration) immediately before valve closure. A high-fidelity, piezoelectric pressure transducer was mounted proximal to the mitral valve and measured the high-frequency pressure fluctuations caused by cavitation bubble formation and collapse after valve closure. The band-pass filtered root mean squared (RMS) value of the mitral pressure signal was used as a measure of cavitation intensity. The combination of these two techniques allowed the direct correlation of valve dynamics and cavitation intensity for each valve closure. The effects of three parameters on prosthetic heart valve dynamics and cavitation were examined: valve geometry (Medtronic Hall and Björk-Shiley Monostrut), occluder material (pyrolytic carbon and Delrin), and gap width between the occluder and housing. A dimensional analysis was also performed to investigate the general form of the relationship between valve dynamics and cavitation intensity. RESULTS: For all of the valves investigated in this study, the RMS pressure increased (signifying an increase in cavitation) as the average closing velocity and deceleration increased. In order to compare the cavitation potential of the valves, the RMS pressure was estimated at specific closing velocities using the linear regression of RMS pressure versus average closing velocity for each valve. The effects of valve geometry, occluder material and gap width were then examined at high valve loading conditions (closing velocity of 4.0 m/s). For both pyrolytic carbon and Delrin, the Medtronic Hall valves had significantly higher RMS pressures than did the Björk-Shiley Monostrut valves. For a given valve geometry, the pyrolytic carbon occluder had a significantly higher RMS pressure than the Delrin occluder. The valve gap width did not have a significant effect on RMS pressure. The dimensional analysis revealed the general relationship among average closing velocity, occluder material properties and cavitation intensity. CONCLUSIONS: The results presented here contribute to our fundamental understanding of cavitation on mechanical heart valves.

Heart Valve Prosthesis↗