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Biomedical subjects

F Guerra

Publications and source records attributed to F Guerra.

At least 55 records · Page 3Linked to original sources
PubMed1990

Long-term performance of the Hancock porcine bioprosthesis in the tricuspid position. A review of forty-five patients with fourteen-year follow-up.

Because little information is available regarding the clinical performance of the Hancock porcine bioprosthesis (Johnson & Johnson Cardiovascular, King of Prussia, Pa.) implanted in the tricuspid position, we reviewed the long-term follow-up of patients who had tricuspid valve replacement with this device. From March 1970 to December 1983, 45 patients had tricuspid valve replacement, either isolated (seven patients) or combined with replacement of other valves (38 patients) by means of a standard, glutaraldehyde-preserved Hancock porcine bioprosthesis. Follow-up ranged from 0.2 to 14.7 years (mean, 7.6 +/- 3.6 years) and was complete. The late mortality rate was 6.6% +/- 1.6%/pt-yr and the actuarial survival rate at 14 years was 23% +/- 9%. Reoperation because of structural deterioration of the tricuspid, the mitral, or both bioprostheses was performed in nine patients (3.7% +/- 1.2%/pt-yr) from 40 to 177 months (mean, 112 +/- 43 months) and resulted in no deaths. Actuarial freedom from structural deterioration of a Hancock tricuspid porcine bioprosthesis at 14 years is 68% +/- 13%. Morphologic examination of explanted porcine bioprostheses showed that those implanted in the tricuspid position had lower degrees of calcification and less severe structural changes than those simultaneously explanted from the mitral position. We conclude that the Hancock porcine bioprosthesis has an acceptable long-term durability and satisfactory performance after tricuspid valve replacement, and we continue to favor its use in the tricuspid position even in association with mechanical prostheses in the left side of the heart.

Adolescent↗
PubMed1989

Mitral valve replacement with the Hancock, Björk-Shiley and Lillehei-Kaster prostheses. A comparison based on a 15-year follow-up.

The performance of the standard Hancock porcine bioprosthesis (HPB), the Björk-Shiley spherical disc prosthesis (BSP) and the Lillehei-Kaster tilting disc prosthesis (LKP) was compared over a 15-year follow-up in patients who underwent isolated mitral valve replacement (502 HPB, 183 LKP and 119 BSP). The cumulative duration of follow-up is 3,488 patient-years (mean, 8.0 +/- 3.7 years) for patients with a HPB, 1,302 patient-years (mean, 8.4 +/- 4.9 years) for patients with a LKP and 718 patient-years (mean, 7.1 +/- 5.6 years) for those with a BSP. At 15 years a significant difference was found among the 3 groups in freedom from (1) anticoagulant-related haemorrhages, between HPB (83% +/- 7%) and BSP (65% +/- 8%) recipients (P less than 0.05); (2) prosthetic dysfunction, BSP (96% +/- 3%) and LKP (83% +/- 6%) versus HPB (42% +/- 5%) recipients (P less than 0.001); (3) overall reoperations, BSP (94% +/- 3%) and LKP (89% +/- 3%) versus HPB (40% +/- 5%) recipients (P less than 0.001) and (4) prosthetic failure, BSP (88% +/- 4%) and LKP (71% +/- 6%) versus HPB (38% +/- 5%) recipients (P less than 0.001). No difference was found in actuarial survival, freedom from thromboembolic episodes, treatment failure and overall prosthesis-related complications. Our results confirm that the long-term performance of the HPB in the mitral position is adversely affected by the high incidence of tissue degeneration while haemorrhagic complications may limit the advantage of the longer durability of mechanical prostheses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
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

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

Allergy to pollen grains from Amaranthaceae and Chenopodiaceae in Cordoba, Spain. Annual and daily variation of pollen concentration.

We have studied the annual and daily variation of pollen grains from Amaranthaceae and Chenopodiaceae for 3 consecutive years. Samples of pollen grains from both families, which make a stenopalynologic group, were collected by the volumetric method with the aid of a Burkard spore-trap. These pollen grains were found to occur in the atmosphere of the city of Córdoba virtually throughout the year, although their presence was continual only between April and October with maximum concentrations detected in the summer months. We have also studied the daily variation of pollen concentration, which peaked between 10 AM and 3 PM. In order to determine the incidence of pollinotic patients sensitive to pollen grains from Chenopodium, we reviewed 1000 clinical records available in the Allergy Unit and found 8.42% to be allergic. On evaluation of the time evolution of the symptoms we found that most patients continued to show them until September each year.

Air Pollution↗
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

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↗
PubMed1988

[Secretory IgA and infantile respiratory pathology].

Secretory component of IgA is the major class of immunoglobulin in secretions and mucous membranes. Many causes have been involved in etiopathogenesis of respiratory tract disease in children, one of them the possible deficit of secretory component of IgA. Authors have studied 191 children with respiratory tract disease secondary to infections and/or allergy and a control group of 35 healthy children. In all of them the secretory IgA non stimulated sputum was measured. In the group with respiratory disease serum IgA, IgG, IgM and IgE were also measured. Levels of secretory IgA were greater in group with respiratory disease than in control; also serum level of IgA was above normal for their ages. Level of secretory IgA was greater in children with "wheezing respiratory disease". These findings do not agree with theory of existence of an IgA secretory deficit as a cause or respiratory tract disease in children.

Adolescent↗