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Biomedical subjects

U Bortolotti

Publications and source records attributed to U Bortolotti.

At least 127 records · Page 7Linked to original sources
PubMed1989

Valve replacement in children: early and late results.

In order to analyze the problems associated with prosthetic valve replacement (PVR) in the pediatric population, we have reviewed 29 children, 3.5 to 15 years of age, who were operated upon from 1970 to 1986. The indications were congenital valve malformations in 16 patients, rheumatic valve disease in 7, degenerative disease in 2 and bacterial endocarditis in 4. Ten children underwent aortic valve replacement (AVR), 14 mitral valve replacement (MVR), 1 tricuspid valve replacement and 4 double valve replacement (mitral-aortic in 3 and mitral-tricuspid in 1). Twenty-one mechanical (11 aortic and 10 mitral) and 12 biological prostheses (8 mitral, 2 aortic, and 2 tricuspid) were implanted. There was 1 hospital death (3.4%). Follow-up data were available for all survivors from 3 to 184 months. There were 8 late deaths (5.9% patient-year), 4 among children with mechanical and 4 among those with biological prostheses. Overall actuarial survival at 14 years is 62.5 +/- 10.2% with no significant difference in survival between AVR (77.8 +/- 14%) and MVR (44.4 +/- 16%) (p = 0.31) at 10 years and between recipients of mechanical (65.7 +/- 13%) or biological prostheses (60.0 +/- 15%) (p = 0.62) at 6 years. No documented embolic or anticoagulant-related complications occurred in the entire series.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1989

Evaluation of Pericarbon valve prosthesis: in vitro, ultrastructural, and animal studies.

Pericarbon, a new generation pericardial valve, is characterized by a single, three cuspal shaped pericardium sheet, which is sutured to a second sheet lining the inner surface of the plastic, low profile stent. A coating of hemocompatible carbon film covers all the exposed, nonbiological surfaces. Optimal preservation of collagen and graft cells is achieved by fresh tissue glutaraldehyde fixation and cusp shaping without mold. Accelerated fatigue testing showed a duration of over 150 million cycles, a figure much higher than that observed when current pericardial and porcine valves were tested with the same apparatus. Results of long-term (greater than 7 months, average 10.5) implantation in 20 sheep (13 mitral, 7 tricuspid) disclosed no case of mechanical failure, mild to moderate primary calcification in older explants, and significant fibrous tissue overgrowth only in the tricuspid position. Transmission electron microscopy studies revealed collagen and elastic fiber integrity, no significant plasma protein insudation, and well-preserved graft cells. Re-endothelialization by host cells was a regular finding on scanning electronic microscopy. Early ultrastructural nuclei of calcification were seen mostly on collagen fibers. Pericarbon presents basic changes in pericardial valve design, and optimal morphological preservation is obtained after industrial processing. Accelerated fatigue tests in vitro show long duration. At medium long-term animal experimental follow-up, mechanical failure was not observed; significant host tissue reaction occurred in the tricuspid but not in the mitral position; primary calcification increased progressively with time and involved mainly collagen fibers.

Animals↗
PubMed1989

Repair of congenital malformations of the mitral valve in children: early and long-term results in 34 cases.

From March 1972 through December 1986, 34 children underwent surgical treatment of mitral valve dysplasia at our institution. There were 14 males and 20 females, with a mean age of 6 years (range, 5 months to 15 years). Eighteen patients had significant mitral valve insufficiency; 16 had significant mitral valve stenosis. Mitral valve reconstruction was possible in 30 patients (88.2%); replacement of the mitral valve with a mechanical prosthesis was necessary in the other 4 patients (11.8%), after at least 1 attempted reconstruction. Five patients died in the hospital (14.7%): 4 after conservative surgery, and 1 after mitral valve replacement. A 6th patient died 26 months after mitral valve replacement and resection of a subaortic membrane. Four patients required reoperation 2 to 66 months after conservative treatment: in 3 of these, the mitral valve was replaced; in the 4th, additional reconstruction was successful. Upon follow-up (range, 3 months to 14 years after surgery), 26 of the 28 surviving patients were asymptomatic; 2-dimensional and Doppler echocardiography performed in 22 patients after mitral valve repair showed normal pulmonary artery pressure in all, and moderate mitral valve dysfunction in 2. Our results indicate that reconstructive surgery for mitral valve dysplasia may prove effective and reliable in children, despite the frequent severity of valve malformation. We believe, therefore, that mitral valve repair should always be attempted in the pediatric population to avoid the disadvantages of prosthetic valve replacement.

Journal Article↗
PubMed1989

Aortic valve replacement with the Hancock standard, Björk-Shiley, and Lillehei-Kaster prostheses. A comparison based on follow-up from 1 to 15 years.

Three series of patients undergoing isolated aortic valve replacement with the standard glutaraldehyde-preserved Hancock porcine bioprosthesis, the standard Björk-Shiley spherical disc prosthesis, and the Lillehei-Kaster tilting disc prosthesis were compared during a 15-year follow-up. From March 1970 to December 1985, aortic valve replacement was performed in 506 patients, 379 men and 109 women, whose ages ranged from 17 to 71 years (mean, 47 +/- 12 years); 196 had a Hancock bioprosthesis, 147 a Björk-Shiley prosthesis, and 163 a Lillehei-Kaster prosthesis. There were no significant differences among the three groups in terms of mean age, preoperative New York Heart Association class, valve lesion, associated intracardiac procedures, and operative mortality (11.7% for the Hancock bioprosthesis group, 8.8% for the Björk-Shiley prosthesis group, and 9.2% for the Lillehei-Kaster prosthesis group). Cumulative duration of follow-up is 1140 patient-years (mean, 6.6 +/- 1.5 years, 100% complete) for Hancock bioprosthesis patients, 878 patient-years (mean, 5.9 +/- 0.4 years, 98% complete) for Björk-Shiley prosthesis patients, and 1184 patient-years (mean, 7.3 +/- 0.3 years, 97% complete) for Lillehei-Kaster prosthesis patients. Actuarial survival rates at 15 years are 30% +/- 15% for Hancock bioprosthesis, 49% +/- 6% for Björk-Shiley prosthesis, and 44% +/- 7% for Lillehei-Kaster prosthesis patients. There were eight embolic episodes in Hancock valve recipients (0.7% +/- 0.1%/pt-yr), nine in Björk-Shiley prosthesis recipients (1.0% +/- 0.3%/pt-yr), and nine (0.7% +/- 0.1%/pt-yr) in Lillehei-Kaster prosthesis recipients (p = no significant difference). Actuarial freedom from emboli at 15 years is 89% +/- 4% for Hancock, 92% +/- 3% for Björk-Shiley, and 93% +/- 2% for Lillehei-Kaster prosthesis recipients (p = no significant difference). A significant difference was found in the incidence of the following complications. (1) Anticoagulant-related hemorrhage: 0.1% +/- 0.1%/pt-yr for Hancock bioprosthesis, 1.3% +/- 0.3%/pt-yr for Björk-Shiley prosthesis, and 1.9% +/- 0.4%/pt-yr for Lillehei-Kaster prosthesis patients (p less than 0.001), with an actuarial freedom at 15 years of 97.6% +/- 1% for Hancock, 85% +/- 5% for Björk-Shiley, and 68.8% +/- 10% for Lillehei-Kaster recipients (p less than 0.001). (2) Structural deterioration: 3.7% +/- 0.6%/pt-yr for Hancock and none for Björk-Shiley and Lillehei-Kaster patients (p less than 0.001), with an actuarial freedom of 100% for Björk-Shiley prosthesis and Lillehei-Kaster prosthesis patients and 38.4% +/- 12% for Hancock bioprosthesis patients at 15 years.

Adolescent↗
PubMed1989

The Hancock II porcine bioprosthesis. A preliminary report.

From May 1983 to July 1987 a total of 153 Hancock II porcine bioprostheses have been implanted in 130 patients with a mean age of 59 +/- 8 years (range 29 to 76 years). Mitral valve replacement was performed in 72 patients, aortic valve replacement in 35, and mitral-aortic valve replacement in 23. Cumulative follow-up of 121 survivors is 223 patient-years and 100% complete (range 0.4 to 4.5 years). The actuarial survival rate at 4 years is 88% +/- 8% for mitral, 86% +/- 7.8% for aortic, and 84% +/- 8% for mitral-aortic valve replacement. Minor thomboembolism occurred in two patients (0.9% +/- 0.6%/pt-yr) with an actuarial freedom from emboli at 4 years of 100% for mitral, 96% +/- 3.7% for aortic, and 91% +/- 8.6% for mitral-aortic valve replacement. Anticoagulant-related hemorrhage occurred in 10 patients (4.4% +/- 1.4%/pt-yr) with an actuarial freedom at 4 years of 90% +/- 4.8% for mitral, 89% +/- 5.8% for aortic, and 84% +/- 10.6% for mitral-aortic valve replacement. Failure of the porcine bioprosthesis was observed in three patients with an actuarial freedom at 4 years of 96% +/- 3.6% for aortic, 91% +/- 8% for mitral, and 91% +/- 8.6% for mitral-aortic valve replacement. Actuarial freedom from all porcine bioprosthesis-related complications at 4 years is 85.7% +/- 6.6% for aortic, 79% +/- 9% for mitral, and 70% +/- 13% for mitral-aortic valve replacement. No instances of primary tissue failure occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1988

The Hancock pericardial xenograft: incidence of early mechanical failures at a medium-term follow-up.

The Hancock pericardial xenograft has been used in our Institution since August 1981 as an alternative to porcine bioprostheses. Up to July 1984, 97 Hancock pericardial xenografts have been implanted in 84 patients; of 76 operative survivors with a mean age of 55.2 +/- 13 years (range 13-75 years), 50 had undergone aortic valve replacement, 16 mitral valve replacement and 10 mitral-aortic valve replacement. Follow-up ranged from 0.5 to 5.2 years with a cumulative duration of 239 patient/years and is 99% complete. Actuarial survival is 92% +/- 4% for patients with aortic valve replacement and 84% +/- 10% for patients with mitral valve replacement at 5 years, and 77% +/- 14% for those with mitral-aortic valve replacement at 4 years. Thromboembolic episodes occurred in 2 patients (1 after aortic and 1 after mitral valve replacement). The actuarial freedom from emboli is 100% for patients with mitral-aortic valve replacement at 4 years, and 96% +/- 3% for patients with aortic and 93% +/- 6% for patients with mitral valve replacement at 5 years. Reoperation was performed in 13 patients (9 aortic, 2 mitral and 2 mitral-aortic valve replacements), because of endocarditis in 3 (2 aortic and 1 mitral valve replacement), paravalvular leak in 1 (aortic valve replacement), and primary tissue failure in 9 (6 aortic, 1 mitral and 2 mitral-aortic valve replacements). Actuarial freedom from primary tissue failure is 72% +/- 9% for aortic and 83% +/- 8% for mitral Hancock pericardial xenografts at 5 years. Eleven xenografts explanted because of primary tissue failure were studied pathologically.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Performance of the Hancock porcine bioprosthesis following aortic valve replacement: considerations based on a 15-year experience.

All patients undergoing isolated aortic valve replacement with a standard Hancock porcine bioprosthesis (PB), from 1970 to 1983, were reviewed. There were 196 patients, 162 male and 34 female patients, with a mean age of 48 +/- 12 years. Operative survivors were followed up from 3 to 15.6 years (mean follow-up, 6.6 +/- 1.5 years), with a cumulative follow-up of 1,140 patient-years, being 100% complete. Actuarial survival was 51 +/- 15% at 14 years. Eight patients sustained systemic embolic episodes (0.7 +/- 0.2%/patient-year); actuarial freedom from emboli is 89.4 +/- 4.3% at 14 years. Reoperation was performed in 53 patients: in 6 because of endocarditis (0.5 +/- 0.2%/patient-year), in 7 because of perivalvular leak (0.6 +/- 0.2%/patient-year), and in 40 because of PB primary tissue failure (3.5 +/- 0.5%/patient-year). Actuarial freedom from PB-related deaths, PB failure, and overall PB-related complications at 14 years was 66.3 +/- 19, 34.3 +/- 11, and 30 +/- 10%, respectively. This long-term experience shows that the performance of the Hancock PB appears satisfactory up to 8 years, while it progressively deteriorates beyond 10 years because of the impact of primary tissue failure on valve durability, justifying the restriction of its use in the aortic position in selected patients.

Actuarial Analysis↗
PubMed1988

Technical considerations in reoperation for porcine bioprosthetic valve failure.

Reoperation in porcine valve recipients is becoming increasingly frequent, owing to the limited durability of the valves. In reviewing our experience with first reoperation for porcine valve failure in 191 patients over a 17-year period, we found that following certain routine surgical steps can minimize complications and improve the surgical outcome. Extended dissection of the heart is useful during mitral bioprosthetic replacement to enhance visualization of the failing device while retracting the left atrium without undue tension on fragile structures such as the left innominate vein-superior vena cava junction. This maneuver can be avoided, however, when replacement of an aortic bioprosthesis is required. Excision of a porcine valve is performed by peeling off the fibrous tissue overgrown on the sewing ring, which exposes the underlying sutures, cutting each knot, and finding a plane between the stent and the native valve annulus by careful blunt dissection. Care is taken not to cut the Dacron cloth of the sewing ring to avoid the potential for embolization of the silicone sponge contained within it. The use of this technique helps to minimize postoperative complications such as paravalvular leak or atrioventricular block and to preserve the native annulus, which facilitates insertion of a new prosthesis. Our experience indicates that first reoperation in porcine valve recipients can be performed with low risk, particularly in elective cases, and with a low incidence of complications related to repeat median sternotomy.

Aortic Valve↗
PubMed1988

The standard Hancock porcine bioprosthesis: overall experience at the University of Padova.

All patients undergoing aortic (AVR, n = 196), mitral (MVR, n = 502), and mitral-aortic (MAVR, n = 71) valve replacement with a standard Hancock porcine bioprosthesis (HPB) from 1970 to 1983 were reviewed. A total of 665 patients discharged were followed for 5,099 patient-years with an actuarial survival at 15 years of 52% +/- 4.5%, for MVR, 37% +/- 14% for AVR, and at 12 years of 52 +/- 7.4% for MAVR. Embolic episodes occurred in 9 patients after AVR (0.7% +/- 0.2% pt-yr), in 61 after MVR (1.7% +/- 0.2% pt-yr), and in 6 after MAVR (1.7% +/- 0.7% pt-yr); actuarial freedom from emboli at 15 years is 91% +/- 3.5% after AVR, 79% +/- 14% after MVR, and at 12 years is 87% +/- 5% after MAVR. Reoperation because of primary tissue failure (PTF) was performed in 47 patients with AVR (3.9% +/- 0.5% pt-yr), 91 with MVR (2.6% +/- 0.3% pt-yr), and in 13 with MAVR (4.1% +/- 1.1% pt-yr); actuarial freedom from PTF at 15 years is 41% +/- 5.5% after MVR, 37% +/- 10% after AVR, and at 12 years is 49% +/- 13% after MAVR. After AVR and MVR, freedom from PTF is significantly better for patients over 50 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Hancock bioprosthetic valve failure: causes, and results of reoperation.

Between March 1970 and the end of December 1986, 180 porcine valve recipients underwent reoperation at our institution because of bioprosthetic failure. Of these patients, 126 (70.0%) had mitral bioprosthesis replacement (MBR), which was necessitated because of primary tissue failure in 107 cases, prosthetic valve endocarditis in eight cases, and paravalvular leakage in eleven cases. Forty-six patients (25.5%) had aortic bioprosthesis replacement (ABR), owing to primary tissue failure in 37 cases, endocarditis in six cases, and paravalvular leakage in three cases. The remaining eight patients (4.5%) all underwent double (mitral and aortic) bioprosthesis replacement (DBR) because of primary tissue failure. In a total of 152 patients who underwent reoperation for primary tissue failure, the hospital mortality was 6.5% for the MBR group, 8.0% for the ABR group, and 0% for the DBR group (mean, 6.5%). In those 14 patients who required reoperation owing to endocarditis, the hospital mortality was 75% for the MBR group and 50% for the ABR group (mean, 64%). In another 14 patients who underwent reoperation because of paravalvular leakage, the hospital mortality was 9% for the MBR group and 0% for the ABR group (mean, 7%). Morphologic studies of the explanted valves revealed that tissue calcification is the most frequent cause of primary tissue failure in Hancock-valve recipients. Calcification leads to cusp stiffening with stenosis or to cuspal and commissural rupture with incompetence. Usually, primary tissue failure causes progressive dysfunction that allows for elective reoperation, which is associated with a low mortality; rarely, however, porcine xenograft failure can occur acutely and require emergency operation, which is associated with a significantly higher risk. Such operation was necessary in nine (6%) of our patients with primary tissue failure and resulted in four deaths (44%); conversely, elective reoperation was done in 143 patients with other primary tissue failure (94%) and resulted in six deaths (4%) (p<0.001). Our long-term experience with the Hancock bioprosthesis confirms that this valve's durability is limited. Therefore, we believe that the indications for the use of porcine bioprostheses should be restricted, until consistent data become available concerning the durability of the new generation of prosthetic valves.

Journal Article↗