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PubMed2004

Percutaneous stent-mounted valve for treatment of aortic or pulmonary valve disease.

The objective of this study was to develop a prosthetic cardiac valve designed for percutaneous transcatheter implantation. Percutaneous catheter-based therapies play a limited role in the management of cardiac valve disease. Surgical implantation of prosthetic valves usually requires thoracotomy and cardiopulmonary bypass. The stent-valve is constructed of a rolled sheet of heat-treated nitinol. Although malleable when cooled, once released from a restraining sheath at body temperature the stent unrolls, becomes rigid, and assumes its predetermined cylindrical conformation. A ratcheting lock-out mechanism prevents recoil and external protrusions facilitate anchoring. Valve leaflets are constructed of bovine pericardium. The feasibility of catheter implantation, prosthetic valve function, and survival were investigated in an animal model. In vitro and pulse duplicator testing documented valve durability. Endovascular delivery of the prototype stent-valve to the aortic or pulmonary position was feasible. Accurate positioning was required to ensure exclusion of the native valve leaflets and, in the case of the aortic valve, to avoid compromise of the coronary ostia or mitral apparatus. Oversizing of the stent in relation to the valve annulus was desirable to facilitate anchoring and prevent paravalvular insufficiency. Stent-valve implantation proved feasible and compatible with survival in an animal model. Transcatheter implantation of prosthetic valves is possible. Further evolution of this technology will involve lower-profile devices with design features that facilitate vascular delivery, visualization, positioning, deployment, and valvular function.

Animals↗
PubMed1983

Echocardiographic evaluation of porcine bioprosthetic valves: experience with 309 normal and 59 dysfunctioning valves.

To determine the clinical value of echocardiographic evaluation of porcine bioprosthetic valves, the findings in all patients who had porcine bioprosthetic valve replacement and adequate quality echocardiographic studies from 1978 to 1982 were analyzed. The study includes 309 normal and 59 dysfunctioning valves. Valve dysfunction resulted from spontaneous cusp degeneration in 39 (34 valve regurgitations, 5 stenoses), infective endocarditis in 12, paravalvular regurgitation in 5, regurgitation of redundant cusps, mitral valve thrombi, and aortic stent stenosis in 3 others. Echocardiographic findings were correlated with gross surgical pathologic or autopsy findings in 45 of the 59 dysfunctioning valves. Echocardiographic abnormalities were demonstrated in 41 of 59 (69%) dysfunctioning valves. A systolic mitral or diastolic aortic valve flutter was diagnostic of a regurgitant valve caused by a torn or unsupported cusp margin and was observed in 28 of 34 (82%) regurgitant valves with no false-positive studies. Echocardiographic cusp thickness of greater than or equal to 3 mm correctly identified all regurgitant and stenotic valves with gross anatomic evidence of localized or generalized cusp thickening or calcific deposits. Echocardiographic valve abnormalities were observed in only 4 of 12 patients with infective endocarditis and in 1 of 5 with paravalvular regurgitation. Thus, echocardiography provides important information regarding the function of porcine bioprosthetic valves and is of value in the decision to replace these valves, especially when dysfunction is due to spontaneous cuspal degeneration. Echocardiography is neither sensitive nor specific in patients with infective endocarditis and paravalvular regurgitation.

Echocardiography↗
PubMed1996

Effect of valve holder flexibility on cavitation initiation with mechanical heart valve prostheses: an in vitro study.

BACKGROUND AND AIM OF THE STUDY: Several in vitro studies have reported on cavitation bubble visualization with mechanical heart valves and the cavitation intensity has been correlated with the design of the valve, the load on the valve occluder, the velocity of the occluder tip, and the negative pressure transients in the vicinity of the occluder. These studies demonstrated the presence of cavitation for certain types of valves under simulated normal physiological loading conditions. However, extrapolation of these results to cavitation initiation in vivo has been questioned due to limitations of the in vitro studies in simulating the in vivo tissue compliance. The present study was intended to analyze the effect of valve holder flexibility (simulating compliance of the suture ring and the surrounding tissue in vivo) on cavitation dynamics. METHODS: Cavitation bubbles were visualized on three types of mechanical heart valves (Medtronic Hall, Edwards-Duromedics, and CarboMedics) in our in vitro set up, and pressure transients were measured close to the occluder at valve closure. Two different flexible valve holders made of Teflon (elastic modulus, E = 400 MPa) and low density polyethylene (E = 180 MPa) were employed and the results were compared with those with a rigid Plexiglas holder (E = 2930 MPa) of the same geometry (3'' by 3'' wide and 1/8'' thick). RESULTS: Significant reductions were noted in the intensity of cavitation bubbles appearing along the clearance region of the Medtronic Hall and CarboMedics valves, with increasing valve holder flexibility. However, no attenuation was observed for the bubbles appearing around the seating lip or stop of the Edwards-Duromedics and Medtronic Hall valves that are believed to be caused by the fluid squeezing effect. CONCLUSIONS: The results of the study suggest that timing of the mechanism to initiate cavitation is a critical factor in cavitation attenuation with flexible valve holders. If cavitation is initiated before the flexible valve holder responds to the impact at valve closure (such as due to squeeze film effect), cavitation intensity remains unchanged. Based on the results of the study, we propose that tissue compliance in vivo may not attenuate cavitation initiation for certain types of mechanical heart valves depending on the cavitation initiation mechanism.

Biomechanical Phenomena↗
PubMed2005

Differentiating clinical and echocardiographic characteristics of chordal rupture detected in patients with rheumatic mitral valve disease and floppy mitral valve: impact of the infective endocarditis on chordal rupture.

AIMS: We aimed to compare the clinical and echocardiographic correlates of chordal rupture in patients with rheumatic mitral valve disease and floppy mitral valve. METHODS AND RESULTS: The study group comprised of 224 patients who underwent transthoracic and transesophageal echocardiography because of the severe mitral regurgitation. Chordal rupture was detected in 58 (25.9%) out of the 224 patients, in 33 out of the 83 (39.7%) patients with floppy mitral valve, and in 25 out of the 141 (17.7%) patients with rheumatic mitral valve disease. Chordal rupture was more frequently associated with anterior leaflet (80%) in patients with rheumatic mitral valve disease, and posterior leaflet (72.7%) in patients with floppy mitral valve (p<0.05). Univariate correlates of chordal rupture were age, male sex, posterior mitral leaflet thickening and chordal elongation in patients with floppy mitral valve (p<0.05), and chordal shortening (p<0.0001) and infective endocarditis involving mitral anterior leaflet (p<0.05) in rheumatic group. Independent predictors of chordal rupture were age (>50 years), posterior mitral leaflet thickness (> or =0.45cm), and male sex (p<0.05) in patients with floppy mitral valve while infective endocarditis involving mitral anterior leaflet (p<0.05) in patients with rheumatic mitral valve disease. Patients with chordal rupture due to floppy mitral valve had an older age (p<0.0001), a male dominance, longer mitral leaflets and chordae, and a larger mitral annulus circumference (p<0.05) as compared to those with rheumatic chordal rupture. Despite the comparable severity of mitral regurgitation and left atrial diameters between the two groups of chordal rupture (p>0.05), functional class and pulmonary artery systolic pressure were higher, and atrial fibrillation, acute deterioration, infective endocarditis, mitral leaflet rupture and need for mitral valve surgery in the 3 months were more frequent in rheumatic chordal rupture subgroup (p<0.05). CONCLUSION: Chordal rupture seems to be more frequently associated with anterior mitral leaflet in rheumatic mitral valve disease, whereas it was the posterior leaflet in floppy mitral valve. Chordal rupture was related to male sex, older age, posterior leaflet thickening, and chordal elongation in patients with floppy mitral valve. However, infective endocarditis, acute deterioration, and need for early mitral surgery were more frequent in patients with rheumatic chordal rupture.

Adult↗
PubMed2005

Valve dysfunction of the cloth-covered Starr-Edwards ball valve.

BACKGROUND: Between June 1968 and March 1977, Starr-Edwards cloth-covered ball valves were used for valve replacement on a routine basis. METHODS AND RESULTS: Among the 66 operative survivors who underwent an isolated aortic or mitral valve replacement, 20 patients required reoperation 22 times because of valve dysfunction, thromboembolic complication, paravalvular leakage, hemolytic anemia, and/or prosthetic valve endocarditis. Reoperation was performed at a mean of 15.9+/-9.8 years after initial replacement. Excised valves were examined and reoperation after initial operation was reviewed. Operative mortality was 10.0%. Freedom from reoperation for aortic valve replacement and mitral valve replacement was 56.2% at 34 years and 61.0% at 37 years after initial operation, respectively. Cloth wear or pannus formation were observed in all excised prostheses. Orifice cloth was more markedly worn in mitral valves than in aortic valves, particularly in mitral valves of more than 20 years old. Pannus overgrowth contributed to valve regurgitation in the older valves. CONCLUSIONS: Early diagnosis of valve dysfunction and reoperation are recommended as soon as symptoms appear.

Adult↗
PubMed2005

A case of aortic valve replacement with St. Jude Medical Regent valve (first implant in Japan).

The St. Jude Medical (SJM) Regent valve was developed as a new mechanical valve by improving the conventional SJM valve. The effective orifice area is wider than that of Hemodynamic Plus (HP) series. The efficacy of the new valve has been reported in Europe and the United States. On October 26, 2004, we first performed aortic valve replacement (AVR) with the SJM Regent valve for aortic valve stenosis in Japan. A 64-year-old female was admitted to our hospital with dyspnea on exertion. She was diagnosed with aortic valve stenosis. She underwent AVR with a 17 mm SJM Regent valve. According to the results of echocardiography conducted two months postoperatively, the peak pressure gradient of the prosthetic valve was 32.0 mmHg, the mean pressure gradient was 13.2 mmHg, and the effective orifice area index (EOAI) was 0.92 cm2/m2. Cinefluoroscopy showed the valve opening angle of 85 degrees indicating full opening. She was discharged 15 days after surgery without complications. As demonstrated by the present case, implantation of a 17 mm SJM Regent valve produced a satisfactory result reflected by lower pressure gradient and absence of patient-prosthetic mismatch. In the future, the new valve is expected to be the optimum mechanical valve for a narrow annulus.

Aortic Valve↗
PubMed1990

Determination of aortic valve area by two-dimensional and Doppler echocardiography in patients with normal and stenotic bioprosthetic valves.

To assess the feasibility and accuracy of determining bioprosthetic aortic valve area from two-dimensional and Doppler echocardiographic measurements, three partially overlapping groups were selected from 55 patients with such bioprosthetic valves and adequate Doppler studies. These were Group 1, 37 patients with recent aortic valve replacement surgery and no clinical or echocardiographic evidence of valve dysfunction; Group 2, 12 patients with prosthetic valve stenosis documented by cardiac catheterization; and Group 3, 22 patients with both Doppler and catheterization studies in whom noninvasive and invasive determinations of aortic valve area could be directly compared. Left ventricular outflow tract diameter was measured from two-dimensional still frame images. Flow velocity proximal to the aortic valve, transvalvular velocity and acceleration time were determined from pulsed and continuous wave Doppler spectra. Aortic valve gradient was calculated with the modified Bernoulli equation and valve area by the continuity equation. In the 37 patients with a normally functioning valve, the calculated mean gradient ranged from 5 to 25 mm Hg (average 13.6 +/- 5.2) and valve area from 1.0 to 2.3 cm2 (mean 1.6 +/- 0.31). Linear regression analysis of prosthetic aortic valve area determined by Doppler imaging and cardiac catheterization demonstrated a high correlation (r = 0.93) between the two techniques. Comparison of the patients with and without prosthetic valve stenosis revealed statistically significant differences in mean gradient (42.8 +/- 12.3 versus 13.6 +/- 5.2 mm Hg; p = 0.0001), acceleration time (116 +/- 15 versus 80 +/- 13 ms; p = 0.0001) and valve area by the continuity equation (0.80 +/- 0.16 versus 1.6 +/- 0.31 cm2; p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2006

What prosthesis should be used at valve re-replacement after structural valve deterioration of a bioprosthesis?

BACKGROUND: The fate of bioprostheses (BP) and mechanical prostheses (MP) after valve re-replacement for bioprostheses is not well-documented. This research compares the late fate of these two valve types after valve re-replacement for structural valve deterioration (SVD) of a bioprosthesis. METHODS: Between 1975 and 2000, 298 patients had successful aortic valve re-replacements (AVRR) (BP n = 149, average age = 67.1 +/- 12.3 years; MP 149, 58.9 +/- 10.9) and 442 patients had successful mitral valve re-replacements (MVRR) (BP 155, 65.8 +/- 14.1; MP 287, 60.8 +/- 11.7) after SVD of a previous BP. Follow-up was five years in all groups. RESULTS: (1) Aortic position (AVRR): Survival favored MP over BP overall, at 10 years (70.3 +/- 5.4% vs 56.7 +/- 5.7%, p = 0.0220). This survival advantage was seen to be significant only in patients less than 60 years of age (at 10 years, 85.3 +/- 4.9% vs 59.2 +/- 9.8%, p = 0.038). No significant difference in survival between the two valve types was observed in patient age groups greater than 60 years of age. Freedoms from valve-specific complications, including reoperation for SVD-thrombosis, major thromboembolism and hemorrhage, and valve-related mortality were not significantly different between the two groups overall. (2) Mitral position (MVRR): Survival favored MP over BP overall (58.6 +/- 4.2% vs 42.1 +/- 5.2%, p = 0.0011), and in patients greater than 70 years of age (32.8 +/- 8.9% vs 16.7 +/- 7.1%, p = 0.008). Freedoms from valve-specific complications and valve-related mortality favored MP over BP. CONCLUSIONS: There was no clinical performance difference between mechanical and bioprosthetic valves in patients greater than 60 years of age upon AVRR. Mechanical valves generally outperformed bioprosthetic valves in all age groups in MVRR.

Age Factors↗
PubMed2002

Aortic valve disease with severe ventricular dysfunction: stentless valve for better recovery.

BACKGROUND: Stentless bioprostheses and homografts show better hemodynamic profiles compared with conventional stented bioprostheses and mechanical valves. Few data are available on stentless aortic valve implantation for patients with severe left ventricular dysfunction. The aim of this retrospective study was to assess the potential benefits of stentless aortic valve implantation for patients undergoing isolated aortic valve replacement with left ventricular ejection fraction < or = 35%. METHODS: From November 1988 through March 2000, 53 patients (45 men and 8 women, aged 64.2 +/- 15.2 years) with a LVEF < or = 35% (mean EF, 28.7 +/- 5.4%) underwent isolated, primary aortic valve replacement for chronic aortic valve disease. Twenty patients received stentless aortic valves and 33 patients received conventional stented bioprostheses and mechanical valves. Predictive factors for LVEF recovery at echocardiographic follow-up (36.2 +/- 32.1 months) were analyzed by simple and multiple regression analysis. RESULTS: There were no significant differences between groups in early and late mortality. Stentless aortic valve implantation required a longer aortic cross-clamp time (p = 0.037). The stentless aortic valve group showed a better LVEF recovery (p = 0.016). Stentless aortic valves had a larger indexed effective orifice area compared with conventional stented bioprostheses and mechanical valves (p < 0.0001). A smaller indexed effective orifice area (p = 0.0008), chronic obstructive pulmonary disease (p = 0.015), and implantation of a conventional stented bioprosthesis or mechanical valve (p = 0.016) were related to reduced LVEF recovery by univariate analysis. A larger indexed effective orifice area (p = 0.024) was an independent predictive factor for a better LVEF recovery by multivariate analysis. CONCLUSIONS: Stentless aortic valve implantation for patients with severe left ventricular dysfunction, even if technically more demanding, is a safe procedure that warrants a larger indexed effective orifice area leading to an enhanced LVEF recovery.

Aortic Valve↗
PubMed1997

An analysis of valve re-replacement after aortic valve replacement with biologic devices.

Biologic valve re-replacement was examined in a series of 1343 patients who underwent aortic valve replacement at The Prince Charles Hospital, Brisbane, with a cryopreserved or 4 degrees C stored allograft valve or a xenograft valve. A parametric model approach was used to simultaneously model the competing risks of death without re-replacement and re-replacement before death. One hundred eleven patients underwent a first re-replacement for a variety of reasons (69 patients with xenograft valves, 28 patients with 4 degrees C stored allograft valves, and 14 patients with cryopreserved allograft valves). By multivariable analysis younger age at operation was associated with xenograft, 4 degrees C stored allograft, and cryopreserved allograft valve re-replacement. However, this effect was examined in the context of longer survival of younger patients, which increases their exposure to the risk of re-replacement as compared with that in older patients whose decreased survival reduced their probability of requiring valve re-replacement. In patients older than 60 years at the time of aortic valve replacement, the probability of re-replacement (for any reason) before death was similar for xenografts and cryopreserved allograft valves but higher for 4 degrees C stored valves. However, in patients younger than 60 years, the probability of re-replacement at any time during the remainder of the life of the patient was lower with the cryopreserved allograft valve compared with the xenograft valve and 4 degrees C stored allografts.

Adolescent↗
PubMed1983

Clinical and echocardiographic assessment of the Medtronic-Hall valve: experience with 370 implanted valves.

During a 34-month period, 370 Medtronic-Hall valves were implanted into 310 patients. Twenty-four percent of patients had additional operative procedures. Hospital mortality was 7% and late mortality to date is 3%. No deaths were due to thromboembolic complications or mechanical failure of the valve. The overall embolic rate was 2.5 per 100 patient years. For mitral valve replacement, the embolic rate was 3.5 per 100 patient years. Patients with isolated mitral valve replacement were subjected to detailed clinical and echocardiographic assessment. Eighty-nine percent of patients with 29 or 31 mm mitral prostheses improved one NYHA class or more and 33% improved 2 classes or more. For the 25 mm mitral prostheses, the figures were 91% and 38% respectively. The peak rate of increase of left ventricular dimension in diastole (dD/dt) was measured echocardiographically in subjects with normal native mitral valves and in patients with 29 or 31 mm Medtronic-Hall valves, Björk-Shiley valves and Starr-Edwards valves. Peak dD/dt in the native valves was 15.8 +/- 0.8, in Medtronic-Hall valves 13.9 +/- 0.8, in Björk-Shiley 11.6 +/- 1.0 and in Starr-Edwards 9.5 +/- 0.6. The Björk-Shiley and Starr-Edwards valves differed significantly from normal (p less than 0.05 and less than 0.001 respectively) but there was no significant difference between the Medtronic-Hall valves and the native ones. We conclude that the Medtronic Hall valve is a safe and hemodynamically effective valve in the mitral position.

Adolescent↗
PubMed1986

St. Jude Medical valve replacement. An evaluation of valve performance.

St. Jude Medical cardiac valve replacement was performed in 791 patients: 335 had aortic, 330 mitral, and 126 had multiple valve replacements. Follow-up extended from 4 to 64 months (mean 34 months) with a cumulative postoperative survival of 2,111 patient-years. The overall actuarial survival rate at 5 years was 76% +/- 3%. Late valve-related mortality occurred in 28 patients (1.33%/pt-yr) and was most often caused by anticoagulant-related hemorrhage. The linearized incidences of valve failure, thromboembolism, thrombotic obstruction, prosthetic valve endocarditis, periprosthetic leak, and all valve-related complications were as follows: 1.80% /pt-yr, 2.45% /pt-yr, 0.52% /pt-yr, 0.33% /pt-yr, 0.14% /pt-yr, and 4.0% /pt-yr, respectively. Actuarially, 94% +/- 2% of patients were free of valve-related mortality at 5 years; the corresponding figures for valve failure, thromboembolism, thrombotic obstruction, and all valve-related complications were 91% +/- 2%, 89% +/- 2%, 96% +/- 1%, and 83% +/- 3%, respectively. Prosthetic valve endocarditis was uniformly fatal, and 45% of patients with thrombotic obstruction died. The greater incidence of thrombotic obstruction after mitral valve replacement was statistically significant. The performance of the St. Jude Medical valve compares most favorably with other substitute valves. Nevertheless, it retains all the imperfections and hazards of other mechanical valves, most notably, thromboembolism and thrombotic obstruction.

Actuarial Analysis↗
PubMed1985

Rest and exercise hemodynamics following aortic valve replacement. A comparison between 19 and 21 mm Ionescu-Shiley pericardial and Carpentier-Edwards porcine valves.

When aortic valve replacement is performed in a patient with a small anulus, significant obstruction of the left ventricular outflow tract may remain. Most prostheses are obstructive in the smaller sizes, and enlargement of the aortic anulus may be required to allow placement of a larger valve. To evaluate the hemodynamic performance of two commonly used tissue prostheses, the Ionescu-Shiley pericardial and Carpentier-Edwards porcine valves, 22 patients with either the 19 or 21 mm size were electively studied at rest and after exercise at a mean of 15 months after operation. The resting mean transvalvular gradient for 19 mm Ionescu-Shiley pericardial valves (n = 7), 10.6 +/- 9.2 mm Hg, was significantly lower than that for 19 mm Carpentier-Edwards valves (n = 3), 33.3 +/- 2.1 mm Hg, p less than 0.01. Following exercise, the mean gradient for 19 mm Ionescu-Shiley pericardial valves rose only to 13.8 +/- 8.5 mm Hg. No exercise data were available for the 19 mm Carpentier-Edwards valve. Among patients with 21 mm Ionescu-Shiley pericardial valves (n = 7), the mean transvalvular gradient at rest was 5.6 +/- 9.5 mm Hg, not significantly different from that of patients with 21 mm Carpentier-Edwards valves (n = 5), 9.8 +/- 18.3 mm Hg. After exercise, the gradients rose to 16.0 +/- 10.0 mm Hg and 25.5 +/- 23.8 mm Hg for the Ionescu-Shiley pericardial and Carpentier-Edwards valves, respectively (no statistical significance). Cardiac index was not different between groups. Gradients were not significantly higher in patients with body surface areas greater than 1.5 m2. It is concluded that the 19 and 21 mm Ionescu-Shiley pericardial valves possess excellent hemodynamics, even after exercise. This valve appears hemodynamically superior to the Carpentier-Edwards valve, particularly in the 19 mm size. Procedures to enlarge the aortic anulus are usually unnecessary when small Ionescu-Shiley pericardial valves are used, even in patients who have large body surface areas.

Adult↗
PubMed2003

Long-term results of mitral valve replacement: biological xenograft versus mechanical valves.

We studied 279 patients who underwent mitral valve replacement at the Department of Thoracic and Cardiovascular Surgery, Hyogo College of Medicine, between November 1973 and December 1998. The patients were divided into two groups based on the type of replacement valve (154 patients in the biological xenograft group and 125 patients in the mechanical valve group), and the long-term results were compared. Clinically satisfactory results were obtained in both the biological xenograft group and the mechanical valve group according to the surgical results, long-term survival, and incidence of prosthetic valve endocarditis. At 15 years, fewer patients in the mechanical valve group than in the biological xenograft group were free of bleeding events (92.5 +/- 3.7% vs 100% P < 0.05). At 15 years, the biological xenograft group was lower than the mechanical valve group with respect to freedom from thromboembolism (72.2 +/- 4.6% vs 93.5 +/- 3.6% P < 0.01), freedom from valve failure (22.0 +/- 5.2% vs 87.0 +/- 4.1% P < 0.005) and freedom from cardiac events (16.5 +/- 3.9% vs 47.2 +/- 14.5% P < 0.01). Though it has previously been suggested that biological xenografts used in mitral valve replacement do not need anticoagulation, the current study suggests the need for anticoagulation with the use of biological xenografts. Mechanical valves require close monitoring of anticoagulation, but their use has decreased the incidence of valve failure and thromboembolism, as compared with the use of biological xenografts. Therefore, mechanical valves are currently the preferred choice for mitral valve replacement. We believe that biological xenografts are indicated only for the older patient (> or =65 years).

Adult↗
PubMed2006

Aortic valve repair for congenital abnormalities of the aortic valve.

BACKGROUND: Due to shortcomings of any valve replacement, repairing and retaining the native valve may be beneficial for congenital aortic valve disease. METHODS: Retrospective review of data and follow-up of aortic valve repair from a single institution. RESULTS: From 1993 to 2001, 56 patients underwent aortic valve repair [median age 13.4 years (range 1 day to 45 years)]. The predominant aortic valve lesion was mixed aortic stenosis/aortic insufficiency 25 (45%), aortic insufficiency 24 (43%) and aortic stenosis 7 (13%). Repair techniques included sub-commissural plication 36 (64%), commissurotomy 24 (43%), cusp plication 15 (27%), pericardial patch cusp extension 8 (14%) and resuspension of commissures 4 (7%). Most patients (88%) required a combination of techniques; 61% required additional procedures. Hospital survival was 55/56 [98%; (95% CI 91-100%)] no patient was discharged on anticoagulation for aortic valve pathology. Fifty-three patients [95%; (95% CI 85-98%)] remain alive after a median follow-up of 37 months; four survivors required aortic valve replacement and two required repeat aortic valve repair [84%; (95% CI 72-91%) reintervention-free survival]. CONCLUSIONS: (1) In this study, aortic valve repair for congenital abnormalities avoided reoperation in the majority of patients, avoided anticoagulation and retained growth potential of the valve. (2) Repeat aortic valve repair or replacement was used to treat subsequent valve deterioration.

Adolescent↗
PubMed2005

Frequency by decades of unicuspid, bicuspid, and tricuspid aortic valves in adults having isolated aortic valve replacement for aortic stenosis, with or without associated aortic regurgitation.

BACKGROUND: Aortic valve stenosis (with or without aortic regurgitation and without associated mitral stenosis) in adults in the Western world has been considered in recent years to most commonly be the result of degenerative or atherosclerotic disease. METHODS AND RESULTS: We examined operatively excised, stenotic aortic valves from 932 patients aged 26 to 91 years (mean+/-SD, 70+/-12), and none had associated mitral valve replacement or evidence of mitral stenosis: A total of 504 (54%) had congenitally malformed valves (unicuspid in 46 [unicommissural in 42; acommissural in 4] and bicuspid in 458); 417 (45%) had tricuspid valves (either absent or minimal commissural fusion); and 11 (1%) had valves of undetermined type. It is likely that the latter 11 valves also had been congenitally malformed. Of the 584 men, 343 (59%) had either a unicuspid or a bicuspid valve; of the 348 women, 161 (46%) had either a unicuspid or a bicuspid aortic valve. CONCLUSIONS: The data from this large study of adults having isolated aortic valve replacement for aortic stenosis (with or without associated aortic regurgitation) and without associated mitral stenosis or mitral valve replacement strongly suggest that an underlying congenitally malformed valve, at least in men, is more common than a tricuspid aortic valve.

Adult↗
PubMed1995

[Rest and exercise performance of allografts, Bicer valves and St. Jude Medical valves in the aortic position].

Cardiac catheterization was performed to measure pressure gradients and hemodynamic parameters at rest and during supine bicycle exercise in 37 patients with aortic valve replacements, using allograft valves. Bicer prosthetic valves and SJM prosthetic valves of 19 to 27 mm diameter. Fourteen patients had an allograft valve replacement, 17 a Bicer valve, and 6 a St. Jude Medical valve. Patients were comparable for age, valve size, body surface area and left ventricular systolic function. There were no statistical differences among three groups for body surface area, left ventricular end-systolic and end-diastolic volume indices, exercise cardiac index, exercise heart rate, or workload achieved. In all 37 patients left ventricular and ascending aortic pressures were measured simultaneously according to the Brockenbrough method. In a 21 mm valve size, the mean pressure gradient was higher for Bicer and St. Jude Medical prosthetic valves than for allograft valves, both at rest (8.0 +/- 3.5 mmHg for Bicer, 5.0 +/- 1.4 mmHg for St. Jude Medical versus 0 +/- 0 mmHg for allograft; p < 0.05) and during exercise (11.0 +/- 4.9 mmHg, 10.0 +/- 2.8 mmHg versus 0 +/- 0 mmHg, respectively: p < 0.05). In a 23 mm size, there were no significant differences among three groups for resting mean pressure gradient, but during exercise the mean pressure gradient was higher for Bicer and St. Jude Medical prosthetic valves than for allograft valves (8.4 +/- 9.3 mmHg, 5.5 +/- 4.4 mmHg versus 0 +/- 0 mmHg; p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

Mechanical heart valve cavitation: valve specific parameters.

Several aspects of mechanical heart valve cavitation, in particular of "severe" vapor cavitation, have been investigated in order to describe the phenomenon of cavitation itself and to classify various mechanical heart valves with respect to their tendency to cavitation. Furthermore, following the results of the measurements, a model for determination of time-dependent physical properties and dynamics of cavitation bubbles, such as size, pressure and temperature was developed. In order to classify the cavitation tendency of mechanical valves, a pulsatile hydraulic-driven circularly mock loop was used. Besides measurements of the relevant hemodynamic parameters, the leaflet velocities of the valves were also determined. In addition, numerous high-resolution pressure measurements, in particular the pressure drops necessary for the initiation of cavitation (local atrial pressure drop), were performed. For the investigation of bubble dynamics, a second pulsatile electro-magnetically-driven tester was used. The influence of density, viscosity and temperature of the fluid on the onset of cavitation was investigated. Cavitation events were recorded with a digital high-speed video camera (up to 40,500 frames/sec) for all investigated heart valves and under different conditions. A critical local upstream pressure drop (located within the model atrium after valve closure) of 450 mmHg was found for all valves as well as a valve specific correlation between left ventricular pressure gradient and local upstream pressure drop. Also, a valve dependent correlation between left ventricular pressure gradient and the local upstream pressure drop was provided. Finally, valve specific parameters were found to predict the cavitation tendency for a specific heart valve. The implementation of a suitable theoretical model allowed conclusions on bubble physics. High pressures (up to 800 bar) and temperatures (up to 1,300 degrees C) at bubble collapse have been determined. The influence of fluid parameters such as density, viscosity and temperature on the onset of cavitation is negligible within physiological range. Critical regions for cavitation for all mechanical heart valves were detected. All mechanical heart valves investigated show cavitation under different conditions (dp/dt) associated with high pressures and temperatures at bubble collapse. Cavitation bubble occurrence depends on valve design and location.

Biophysical Phenomena↗