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Biomedical subjects

V Martelli

Publications and source records attributed to V Martelli.

At least 37 records · Page 2Linked to original sources
PubMed1980

Long-term performance of homograft and autograft valves.

Five hundred and eighty homograft valves have been inserted into the aortic position as isolated valve replacements, and followed up for 7--14 years. After ten years 90% of frozen homografts, 80% of autografts and 70% of freeze-dried homografts were free of valve-related death. There was only one embolism reported giving an incidence of one embolism per 143,928 patient months. Degeneration occurred in 14% of the autografts, in 30% of the freeze dried and in 60% of the frozen homografts after ten years. Eighty per cent of the fresh homografts have been free of degeneration after seven years, and 54% of freeze-dried valves have been free of degeneration after 14 years. Long-term performance of homograft and autograft valves in the aortic positon is comparable to that of any prosthetic or bioprosthetic valve. In addition, they are non-thrombogenic and excellent in terms of patient survival.

Aortic Valve↗
PubMed1980

Mitral valve replacement with dura mater bioprostheses.

Dura mater bioprostheses for cardiac valve replacement were first introduced in Brazil. They have been used since 1975 at the National Heart Hospital, London, as a mitral valve replacement instead of fascia lata valves or inverted aortic homograft valves. During this period 120 patients have had dura mater valves inserted in the mitral position; 29 also received an aortic valve replacement, 6 with dura mater, 20 with an aortic homograft, 2 with an aortic xenograft and 1 with a prosthetic valve. Perivalvular leaks occurred with seven of these mitral valves, and another seven presented with detached cusps. All but one of these 14 valves were replaced. Emboli have occurred in four of the patients, one of whom died after 35 months with thrombus on the aortic valve, but with an unaffected mitral valve. There were 15 early deaths, a hospital mortality of 12.5%, and 10 late deaths, a postoperative mortality of 9.5%. Actuarial analysis has shown a four-year postoperative survival of 78.9%.

Aortic Valve↗
PubMed1979

Long term performance of 580 homograft and autograft valves used for aortic valve replacement.

Homograft valves have been used at the National Heart Hospital since 1964, and autograft valves since 1967. The homografts were treated either by freeze drying, by flash freezing, or by tissue maintenance in a nutrient medium (fresh). In order to compare these three groups of homograft valves with the autograft valves some long term assessment of valve function was required. In the whole group of 580 valves there have been 40 late deaths, which is a probability of only 7% over 6 to 14 years. Homografts and autografts are therefore excellent valves in terms of patient survival. Thromboembolism, haemolysis and bleeding may be regarded as complications which do not occur with homograft and autograft valves. There was one thrombogenic episode in this group, an incidence of one per 11,994 patient years and a probability of only 0.000083 patient years. Potentially fatal hazards of late complications with homoor autograft valves decrease with time and at this time is a negligible factor. The similarity in pattern of onset of late infections and degeneration probably reflects the greater susceptibility to infection of a degenerating valve. All three groups of homografts are very similar and differ only from the excellent performance of the autograft valves.

Aortic Valve↗
PubMed1979

An 11-year assessment of 93 flash-frozen homograft valves in the aortic position.

Flash-frozen homograft aortic valves were used for isolated aortic valve replacement at the National Heart Hospital between 1968 and 1971. This study of 93 patients with an average follow-up of 8.5 years complements a previous report on 30 patients but shows a higher incidence of degeneration. There was an early mortality of 4.8% and a late mortality of 15.9% over 11 years. Only five of the 15 late deaths were directly attributable to valve malfunction. There were no episodes of thromboembolism during the 11 year follow-up and only three cases of infective endocarditis. Despite the late onset of valve degeneration there is a 77% probability of patient survival at 11 years. The use of frozen valves delayed the time of onset of degenerative changes when compared over an 11-year period with the earlier use of freeze-dried valves. The evaluation of replacement cardiac valves is thus seen to be time-dependent and needs a long follow-up and an adequate number of patients in the sample for a meaningful assessment. There was no significant difference in the long-term performance between the frozen valves sterilized in ethylene oxide or sterilized with gamma irradiation.

Adult↗
PubMed1976

Reconstruction of right ventricular outflow tract with a valved conduit in 75 cases of congenital heart disease.

Reconstruction of the right ventricular outflow tract with an aortic homograft conduit was performed in 75 patients from 1966 to 1974. The types of congenital heart disease were as follows: pulmonary atresia, 35 cases; severe tetralogy of Fallot, 22 cases; truncus arteriosus, 6 cases; transposition of the great arteries (TGA), 3 cases; single ventricle, 2 cases; and tricuspid atresia, 7 cases. Ninety per cent of the patients had one or more previous shunts, and this was a factor affecting the mortality rate. Other factors included age, pulmonary vascular resistance, surgical anatomy, and technical problems such as bleeding, prolonged bypass, coronary artery injury, and compression of the conduit by the sternum. Our present approach is to avoid shunts, define the anatomy precisely by angiography, and to attempt total correction when severe hypoxia or effort intolerance occurs or before increased pulmonary vascular resistance develops.

Adolescent↗
PubMed1975

Analysis of homograft valve failure in 311 patients followed up to 10 years.

Homograft aortic valve replacement was performed in 311 patients at the tnational Heart thospital, London, between 1964 and 1973. Valve failure has occurred in 61 patients (20%), 32 of whom survived reoperation. From 1963 through 1967, 156 valves were freeze-dried and account for 56 of the valve failures. From 1968 to 1973, 118 fresh or fresh-frozen valves resulted in only 5 failures. Six general types of failure have been identified: calcification (13), dehiscence (15), infective endocarditis (17), prolapse (6), cusp degeneration (5), and tear or perforation (5). Valve failure may be due to surgical technical error resulting in dehiscence or valve incompetence, or it may be related to degenerative changes in the homograft. The clinical results, supported by gross and histological examination and viability testing, enable us to conclude that fresh or fresh-frozen valves are superior to freeze-dried valves, having resulted in only 4% valve failure over the past five years.

Aortic Valve↗
PubMedDate not supplied

Regurgitant flow of mitral valve prostheses: an intraoperative transesophageal echocardiographic study.

To assess the regurgitant characteristics of mitral biologic and mechanical prostheses immediately after implantation, intraoperative transesophageal echocardiography was performed in 27 patients, aged 32 to 69 years, undergoing open-heart surgery for rheumatic heart disease (n = 19), mitral valve prolapse (n = 3), malfunctioning prostheses (n = 3), or periprosthetic leaks (n = 2). The prostheses included 13 biologic (Carpentier-Edwards) and 14 mechanical valves (five Starr-Edwards, five Medtronic-Hall, and four Bjork-Shiley). Physiologic transvalvular regurgitant flow was detected in both biologic and mechanical prostheses. The spatial extent of the regurgitant jets was usually greater in the mechanical than in the biologic valves, and systolic jets, characteristic of each type of valve, were visualized consistently. Trivial periprosthetic jets (PPJs) were observed in many implanted valves (14/27). The median maximal jet area was 0.46 cm2 (range 0.1 to 1.5 cm2). Cardiopulmonary bypass was reinstituted in two patients. In one patient a PPJ was judged extensive enough (area 3.6 cm2) to warrant surgical revision of the implant, but no dehiscence was found. In the other patient a turbulent PPJ (area 5.5 cm2) was associated with a 0.5 cm dehiscence at the surgical inspection. In conclusion, (1) all mitral prostheses exhibit physiologic transvalvular regurgitation, (2) trivial mitral PPJ is a common finding in newly implanted mitral valves and does not require the revision of the implant, and (3) further experience based on larger series of patients is required to determine the maximal acceptable size of a mitral PPJ detected by intraoperative transesophageal echocardiography.

Bioprosthesis↗