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PubMed1998

Time-frequency and time-scale techniques for the classification of native and bioprosthetic heart valve sounds.

The determination of diagnostic features in recorded heart sounds was investigated with Carpentier-Edwards (CE) bioprosthetic valves. Morphological features, extracted using the Choi-Williams distribution, achieved between 96 and 61% correct classification. The time-scale wavelet-transform feature set achieved 100% correct classification with native valve populations, and 87% with the CE replacements.

Aortic Valve↗
PubMed1977

The glutaraldehyde-treated heterograft valve: some engineering observations.

Two commercially prepared, glutaraldehyde-treated porcine heterograft valves mounted on flexible stents have been tested in a pulsatile-flow water tunnel. Measurements of the radial deflections of the stent posts have been made for various applied pressures across the valve. A previous claim of 90 percent reduction in leaflet stress as a result of stent flexibility is of doubtful validity because the measurement technique used was inappropriate for the magnitude of strain involved. Photographs of the valve at various steady forward flow rates show that the leaflets do not open as readily as the antibiotic-treated homograft valve.

Aldehydes↗
PubMed2004

Effect of fibroblast growth factor-2 on pannus formation in replacement prosthetic heart valves.

BACKGROUND AND AIM OF THE STUDY: Fibroblast growth factor-2 (FGF-2) is a multifunctional protein which plays a role in smooth muscle cell growth, wound healing, tissue repair and angiogenesis. FGF-2 is also released by mechanically wounded cells. Herein, the importance of FGF-2 release from periannular tissue in the mechanism of pannus formation in obstructed mechanical prostheses was investigated. METHODS: Between January 1993 and December 2002, 35 patients with an obstructed bileaflet prosthetic mitral valve were classified according to the nature of obstruction as either thrombus or pannus. Data were related to patient age and gender, prosthesis model and size, intraoperative and pathology findings, and interval between implant and thrombosis. FGF-2 release was monitored immunohistochemically in all cases. RESULTS: Thrombus formation was found in 19 patients, and pannus formation in 16. Patients were reoperated on after 3.10 +/- 0.7 years in the thrombus group, and after 6.3 +/- 0.46 years in the pannus group (p = 0.04). A foreign body reaction was found 78.9% of thrombus patients and 81.2% of pannus patients (p = 0.602), chronic inflammation in 31.5% and 50%, respectively (p = 0.317), and FGF-2 release in 78.9% and 87.5%, respectively (p = 0.582). CONCLUSION: As FGF-2 release was similar in both patient groups, the duration of FGF-2 release from injured periannnular tissue was considered to form part of the chronic healing process, and was not attributed to mitral valve obstruction by pannus formation.

Adult↗
PubMed2006

Late-term results of mitral valve replacement with St. Jude Medical mechanical valve prosthesis: Samsun experience.

BACKGROUND AND AIM OF THE STUDY: We have reported the short- and long-term results of mitral valve replacement in this article. METHODS: Mitral valve replacement was conducted in 276 patients in our clinic between January 1989 and March 2005. The youngest patient was 4 years old and the oldest patient was 74 years old. Mean age was 40.08 +/- 1.06 y. Of these patients, 41.3% were men and 58.7% were women. The reason for operation was mitral stenosis in 96 patients (34.78%), mitral insufficiency in 78 patients (29.26%) and mitral stenosis plus mitral insufficiency in 102 patients (36.96%). The aetiology of mitral valve lesions was acute rheumatic fever in 208 patients (75.36%). The aetiology of mitral valve lesions was degenerative in 37 patients (13.41%), ischaemic in 23 patients (8.33%) and congenital in 8 patients (2.9%). RESULTS: In the 5, 10 and 15-year periods, the actual survival rates were 87.64% +/- 2.02%, 83.35% +/- 2.38% and 68.19% +/- 5.63%, respectively. Thromboembolism was observed in 38 patients (13.77%). The rates of actual freedom from thromboembolism in the 5, 10 and 15-year periods were 93.08% +/- 1.53%, 88.48% +/- 1.99% and 81.06% +/- 3.43%, respectively. Of the 276 patients who had been observed for 15 years, 5 had (1.81%) valvular thrombosis. The rates of actual freedom from valvular thrombosis in the 5, 10 and 15-year periods were 98.89% +/- 0.64%, 98.04% +/- 0.87% and 98.04% +/- 0.87%, respectively. In the 15-year period, 23 patients (8.33%) had haemorrhage due to anti-coagulation. The rates of actual freedom from haemorrhage due to anti-coagulation in the 5, 10 and 15-year periods were 95.64% +/- 1.23%, 93.40% +/- 1.56% and 87.73% +/- 2.96%, respectively. Seven patients (2.54%) had prosthetic valvular endocarditis. The rates of actual freedom from endocarditis in the 5, 10 and 15-year periods were 98.51% +/- 0.74%, 97.60% +/- 0.97% and 97.01% +/- 1.13%, respectively. Nine patients (3.27%) were re-operated. The rates of actual freedom from re-operation in the 5, 10 and 15-year periods were 97.45% +/- 0.95%, 96.58% +/- 1.12% and 96.58% +/- 1.12%, respectively. CONCLUSIONS: St. Jude Medical mechanical valve prosthesis has been the valve of choice in our clinic owing to its excellent haemodynamic properties and low rates of complication.

Adolescent↗
PubMed2003

The Quattro valve in rheumatic mitral valve disease: four-year follow up.

BACKGROUND AND AIM OF THE STUDY: There remains a great need for bioprosthetic valves in developing countries where monitoring of anticoagulation therapy is difficult. The study aim was to assess the intermediate outcome following mitral valve replacement with a stentless bovine pericardial quadrileaflet mitral (Quattro) valve. This valve maintains mitral annular-papillary continuity in patients with isolated severe rheumatic mitral valve disease. METHODS: Since December 1996, the Quattro valve has been implanted in 47 patients (mean age 34 +/- 13 years; 16 (34%) aged <25 years) with rheumatic mitral valve disease. All patients were symptomatic, and in NYHA class II (n = 7), III (n = 30) or IV (n = 10). Preoperatively, all patients underwent full clinical and routine echocardiographic assessment, as well as intraoperative transesophageal evaluation after valve implantation. At follow up visits, clinical and echocardiographic evaluations were carried out in each patient. RESULTS: After a mean follow up of 51 +/- 11 months, the overall mortality was 10.6% (five deaths). Five patients did not return for clinical follow up, but three of these are known to be alive and well. Of the 37 patients who returned for regular follow up, 32 remained symptomatically improved. Valve explantation was performed in two patients (4.2%) for prosthetic valve endocarditis. Two patients have deteriorated as a result of left ventricular dysfunction, and one patient has developed severe mitral regurgitation. Thromboembolism or clinically overt hemolysis has not occurred. One patient, who was receiving coumadin therapy for atrial fibrillation, died following a massive hematemesis. Serial one-year echocardiography data at one, two and three-year follow up intervals were available in 28 patients. These data confirmed no significant change in valve area or in mean diastolic gradient. Varying degrees of valve thickening were detected echocardiographically in 10 patients; four patients had clinically significant mitral stenosis (valve area <1.5 cm2). One valve was explanted for structural deterioration. CONCLUSION: Intermediate results after Quattro valve implantation in a relatively young population were satisfactory. However, long-term follow up is mandatory to assess valve durability.

Adult↗
PubMed2004

Anterior leaflet augmentation with autologous pericardium for mitral repair in rheumatic valve insufficiency.

BACKGROUND AND AIM OF THE STUDY: The mechanism of insufficiency in rheumatic valve disease includes annulus dilatation and restricted leaflet motion. In order to improve the treatment of restriction, the anterior mitral leaflet (AML) can be augmented with a piece of glutaraldehyde-treated autologous pericardium. METHODS: Between January 1995 and December 1999, among 274 patients referred for rheumatic mitral disease, 143 (52%) underwent a valve repair. Of these patients, 81% had pure regurgitation and 19% had significant associated stenosis. Ring annuloplasty was used in all cases. Techniques used to treat the restrictive component of the regurgitation were compared in two consecutive cohorts of patients, either with (n = 62) or without (n = 81) AML augmentation. Mean patient age was 42 +/- 3 years, and all preoperative variables were comparable except for the incidence of redo patients, who all underwent AML extension. RESULTS: In-hospital mortality was 0.7% (n = 1 with AML extension), and there was one early reoperation for pericardial patch dehiscence. After a mean follow up of 3.2 years, there was one sudden death (no AML extension). The reoperation rate was lower with (2.5%) than without (12.9%) AML augmentation (p <0.05). Echocardiography showed a lower incidence in recurrence of mitral insufficiency when AML augmentation was performed (grade 2, 9% versus grade 3, 3%) as compared to no AML augmentation (grade 2, 35% versus grade 3, 14%) (p <0.05). The mitral orifice area was larger (AML augmentation 2.2 +/- 0.3 cm versus no AML augmentation 1.8 +/- 0.4 cm2). CONCLUSION: Ring annuloplasty alone failed to correct rheumatic mitral insufficiency in all cases. AML augmentation improved the quality of the repair, and decreased the risk of reoperation.

Adolescent↗
PubMed2003

Twenty-year experience with the St Jude Medical mechanical valve prosthesis.

BACKGROUND: We have prospectively followed all adult St Jude Medical mechanical valve recipients at the Medical University of South Carolina since the initial implant in January 1979 and now present our 20-year experience. METHODS: We prospectively followed 837 valve recipients (aortic valve replacement; n = 478; mitral valve replacement; n = 359) from January 1979 to December 2000 at 12-month intervals. RESULTS: Ages ranged from 19 to 84 years. Follow-up averaged (mean +/- standard deviation) 7 +/- 5 years (98% complete). Patients were in New York Heart Association class III or IV in 77% (aortic valve replacement) and 89% (mitral valve replacement) preoperatively. A 19-mm valve was implanted in 15.5% of aortic valve replacement patients. Coronary bypass was required in 31% of aortic valve replacements and 20% of mitral valve replacements. Operative mortality was 17/478 (3.6%) in aortic valve replacement and 19/359 (5.3%) in mitral valve replacement, and multivariable predictors were 19-mm valve size, 3 or more coronary bypass grafts, and New York Heart Association class IV for aortic valve replacement and New York Heart Association class IV and age for mitral valve replacement. Actuarial survivorship at 10 and 20 years was 57% +/- 3% and 26% +/- 5% for aortic valve replacement and 61% +/- 3% and 39% +/- 4% for mitral valve replacement. Multivariable predictors of late death were African-American ethnicity, New York Heart Association class III or IV, coronary bypass, and age for aortic valve replacement and New York Heart Association class III or IV, coronary bypass, and age for mitral valve replacement. For aortic valve replacement, effective orifice area was univariately (P =.002) but not multivariately (P =.378) predictive of late death. Structural valve deterioration was not observed. For aortic valve replacement, actuarial freedom (at 10 and 20 years) from reoperation was 93% +/- 1% and 90% +/- 2%; thromboembolism, 82% +/- 3% and 68% +/- 8%; bleeding events, 77% +/- 3% and 66% +/- 6%; prosthetic valve endocarditis, 94% +/- 1% and 94% +/- 1%; valve-related mortality, 94% +/- 2% and 86% +/- 4%; and valve-related mortality or morbidity, 58% +/- 3% and 32% +/- 8%. For mitral valve replacement, actuarial freedom (at 10 and 20 years) from reoperation was 96% +/- 1% and 90% +/- 3%; thromboembolism, 77% +/- 3% and 59% +/- 7%; bleeding events, 86% +/- 2% and 65% +/- 8%; prosthetic valve endocarditis, 98% +/- 1% and 96% +/- 2%; valve-related mortality, 89% +/- 0.2% and 74% +/- 8%; and valve-related mortality or morbidity, 63% +/- 3% and 29% +/- 7%. CONCLUSIONS: After 2 decades of observation with close follow-up, the St Jude Medical mechanical valve continues to be a reliable prosthesis.

Actuarial Analysis↗
PubMed1998

Is atrial fibrillation resulting from rheumatic mitral valve disease a proper indication for the maze procedure?

BACKGROUND: There are a few patients without detectable atrial contraction despite restoration of atrial rhythm after the maze procedure for atrial fibrillation (AF) associated with mitral valve disease. METHODS: From January 1995 to March 1997, 29 consecutive patients with AF associated with mitral valve disease underwent our modified maze procedure combined with mitral or other valve operations. The causes of mitral valve disease were rheumatic mitral stenosis (n = 22) and nonrheumatic mitral regurgitation (n = 7). The 17 patients with postoperative atrial rhythm were divided into group I with rheumatic mitral stenosis (n = 10), and group II with mitral regurgitation of nonrheumatic origins (n = 7). RESULTS: Seventeen patients regained atrial rhythm, 2 patients had junctional rhythm, and another 10 remained in AF. Between the group of patients with restoration of atrial rhythm and that of patients remaining in AF, significant differences were found in the percentage with rheumatic disease, history of AF, and maximum f-wave voltage. The postoperative peak velocity of the atrial filling wave to peak velocity of early filling wave ratio for the left atrium measured using Doppler echocardiography was 0.25 in group I, which was significantly lower than that (0.42) in group II. CONCLUSIONS: Reconsideration of the indications for the maze procedure for AF associated with rheumatic mitral stenosis may thus be reasonable, particularly for cases in which replacement using a prosthetic valve is necessary, but we believe that patients with nonrheumatic mitral valve disease, especially those able to undergo reconstructive operations, are the best candidates for the maze procedure.

Adult↗
PubMed1998

Repair of nonsevere rheumatic aortic valve disease during other valvular procedures: is it safe?

OBJECTIVE: To investigate the long-term performance of aortic valve repair, we analyzed the results obtained in a 22-year period in patients who underwent repair of nonsevere rheumatic aortic valve disease during other valvular procedures. METHODS: Fifty-three patients (mean 40 +/- 11.6 years of age) with predominant rheumatic mitral valve disease had concomitant aortic valve disease in association with serious tricuspid valve disease in 25 of them. Preoperatively, aortic valve disease was considered moderate in 47.2% of the patients and mild in 52.8%. All patients underwent reparative techniques of the aortic valve (free edge unrolling, 44; subcommissural annuloplasty, 40; commissurotomy, 36) at the time of mitral or mitrotricuspid valve surgery. The completeness of follow-up during the closing interval was 100%, with a mean follow-up of 18.8 years (range 8 to 22.5 years). RESULTS: Hospital mortality rate was 7.5%. Of 49 surviving patients, 26 (53.1%) died during late follow-up. The actuarial survival curve including hospital mortality was 35.4% +/- 8.7% at 22 years. For patients who underwent mitral and aortic valve surgery, the actuarial survival curve at 22 years was 32.3% +/- 13%, whereas for patients who had a triple-valve operation the survival was 37.0% +/- 10.1% (p = 0.07). Twenty-five patients underwent an aortic prosthetic valve replacement. Actuarial free from aortic structural deterioration and valve-related complications at 22 years was 25.3% +/- 9.3% and 12.7% +/- 4.8%, respectively. CONCLUSIONS: Long-term functional results of reparative procedures of nonsevere aortic valve disease in patients with predominant rheumatic mitral valve disease have been inadequate at 22 years of follow-up. According to these data, conservative operations for rheumatic aortic valve disease do not seem appropriate.

Adolescent↗
PubMed2005

Complications of supra-annular mitral valve placement in infants.

Two infants underwent supra-annular placement of prosthetic mitral valves. The objective of this strategy was to insert a larger valve and delay replacement. This approach was initially successful but by two and three years later the patients developed impairment of cardiac function. The prosthesis decreased the volume and compliance of the left atrium causing high left atrial and pulmonary venous pressures. The "ventricularised" atrium below the prosthesis dilated. In neither case was it possible to delay second valve replacement.

Female↗