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Biomedical subjects

F Guerra

Publications and source records attributed to F Guerra.

At least 73 records · Page 4Linked to original sources
PubMed1988

Repair of congenitally malformed mitral valve in children.

We report our experience with 30 children under 15 years of age treated surgically for congenital mitral valve disease from March 1972 to July 1986. Valve reconstruction was possible in 26 patients (87%), whereas in four the valve was replaced with a mechanical prosthesis. Five patients died in the hospital (16.6%), four after conservative operations and one after mitral valve replacement. There was only one late death in a child in chronic congestive heart failure. Three patients, treated conservatively, required valve replacement 2, 22, and 24 months, respectively, after the operation. Follow-up data reveal that 22 of 24 patients are asymptomatic 5 months to 15 years after operation. Two-dimensional echocardiographic studies were performed in 19 patients treated conservatively, 17 of whom are asymptomatic. Eleven of them have no signs of mitral regurgitation or stenosis, six show only mild mitral incompetence, and two have moderate mitral regurgitation or stenosis. Peak pulmonary artery pressure is within normal limits in all. Our results indicate that mitral valve reconstructive procedures for congenital valve dysplasia may be effective and reliable in children despite the frequent severity of valve malformation. Although no major prosthesis-related complications were observed in the present series, we believe that mitral valve repair should always be attempted in the pediatric population to avoid the drawbacks of the currently available prostheses.

Adolescent↗
PubMed1987

Long-term durability of the Hancock porcine bioprosthesis following combined mitral and aortic valve replacement: an 11-year experience.

Long-term evaluation of patients undergoing combined mitral and aortic valve replacement (MVR + AVR) with a porcine bioprosthesis provides the opportunity for a direct comparison of the durability of the mitral versus the aortic porcine bioprosthesis in the same patient. From 1970 to 1983, 71 patients underwent MVR + AVR with Hancock porcine bioprostheses. There were 46 men an 25 women ranging in age from 21 to 64 years (mean, 47.5 +/- 5 years). Sixteen patients (22.5%) died at operation. The survivors were followed from 0.2 to 11.5 years (mean, 5.7 +/- 3 years). Duration of follow-up was 313 patient-years and was 100% complete. Overall late mortality was 6.7 +/- 1.4% per patient-year (linearized incidence), and actuarial survival was 54.2 +/- 8% at 11 years. Endocarditis occurred in 4 patients (linearized incidence of 1.3 +/- 0.6% per patient-year); thromboembolic events were sustained by 4 patients (linearized incidence of 1.3 +/- 0.6% per patient-year); the event was fatal in 1 patient. Actuarial freedom from thromboembolism was 90 +/- 4.8% at 11 years. Reoperation for primary tissue failure was performed in 11 patients (linearized incidence of 3.5 +/- 1% per patient-year) with no deaths; in 7 patients both bioprostheses were explanted, and in 4, only the mitral bioprosthesis was replaced. The durability of explanted aortic and mitral porcine bioprostheses was not significantly different, and the evaluation of seven pairs of explanted aortic and mitral bioprostheses showed similar amounts of calcification. Actuarial freedom from reoperation because of primary tissue failure was 44.6 +/- 13.7% at 11 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1987

Early mechanical failures of the Hancock pericardial xenograft.

From August 1981 to July 1984, a total of 97 Hancock pericardial xenografts were implanted in 84 patients, whose ages ranged from 13 to 75 years (mean 55.7 +/- 13). Mitral value replacement was performed in 17, aortic valve replacement in 54, and mitral-aortic valve replacement in 13. Operative survivors were reevaluated from July to September 1985. Cumulative duration of follow-up is 167 patient-years (range 0.5 to 4.1 years), and follow-up is 99% complete. The overall late mortality (at 4 years) is 3.6% +/- 1.4% per patient year, and the actuarial survival rate is 95.4% +/- 3% for aortic valve replacement, 74.7% +/- 16.5% for mitral valve replacement, and 67.1% +/- 20.7% for mitral-aortic valve replacement. One patient sustained a thromboembolic event after mitral valve replacement, but no such complications occurred after aortic or mitral-aortic valve replacement. Actuarial freedom from embolism at 4 years is 100% for aortic and mitral-aortic valve replacement and 93.3% +/- 6.4% for mitral valve replacement. Reoperation for Hancock pericardial xenograft dysfunction was performed in seven patients (five aortic and two mitral-aortic). In the aortic valve replacement group the causes were endocarditis in one, paravalvular leak in one, and primary tissue failure in three; all survived reoperation. The two patients with mitral-aortic valve replacement required reoperation because of primary tissue failure of both Hancock pericardial xenografts, and one died. All values explanted because of primary tissue failure showed commissural tears causing severe prosthetic regurgitation. Calcium deposits were severe in one and mild but unrelated to the cusp rupture in another. Collagen disarray was seen only at the site of the tears, whereas the collagen structure was well preserved in the intact parts of the cusps. Four patients with aortic valve replacement and one with mitral valve replacement show evidence of Hancock pericardial xenograft failure and are awaiting reoperation. The actuarial freedom from primary tissue failure at 4 years is 74.3% +/- 9.8% for aortic and 78.9% +/- 13.2% for mitral Hancock pericardial xenografts. At medium-term follow-up, the Hancock pericardial xenograft has shown poor durability and an extremely high rate of early mechanical failure, especially in the aortic position. These observations suggest the need for a close follow-up of Hancock pericardial xenograft recipients and possibly elective reoperation in asymptomatic patients with clinical evidence of prosthetic failure. These results have led us to discontinue the clinical use of this pericardial xenograft.

Adolescent↗
PubMed1987

Dissecting cuspal hematomas. A rare form of porcine bioprosthetic valve dysfunction.

Large dissecting cuspal hematomas (DCHs) were present in six (3%) of 193 porcine bioprostheses (PBs) explanted at reoperation. In four mitral PBs, the DCHs contributed to valve dysfunction; in one aortic PB, DCH was the only determinant of failure, causing stenosis by cusp thickening and rigidity. In another mitral PB, DCHs were occasionally found in the setting of valve incompetence due to commissural tears. While confirming that DCHs are a potential but infrequent cause of PB failure, these observations demonstrate that they may involve PBs implanted both in mitral and aortic position and might be a complication of anticoagulation.

Adult↗
PubMed1986

Awareness and recall.

Awareness and recall under anesthesia is a complication that appears to be related to the use of muscle relaxants. While little is known about unconscious awareness and its physical and psychological consequences, it is well known that recall can result in traumatic psychological sequelae under certain circumstances. The anesthesiologist must be aware of the possibility of awareness before it occurs and either try to avoid it or explain to the patient the possibility of awareness and the circumstances under which it might occur. In the event of unexpected awareness, the anesthesiologist must deal with the patient in an honest and forthright manner. Failure to do so may lead to dire psychological consequences for the patient and legal consequences for the anesthesiologist.

Anesthesia, General↗
PubMed1986

[Not Available].

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Americas↗
PubMed1986

[Not Available].

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Historiography↗
PubMed1986

[Not Available].

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Americas↗
PubMed1986

[Not Available].

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History, Early Modern 1451-1600↗
PubMed1986

[Not Available].

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Americas↗
PubMed1985

[Not Available].

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Americas↗
PubMed1985

Results of reoperation for primary tissue failure of porcine bioprostheses.

Results of reoperation for primary tissue failure of porcine bioprostheses were evaluated in 574 patients discharged from the hospital from 1970 to 1981. A total of 413 had undergone isolated mitral valve replacement and 161 isolated aortic valve replacement. Through March, 1984, 88 patients (15%) had required reoperation: 59 had undergone mitral and 29, aortic valve replacement. Primary tissue failure was the main cause of bioprosthetic dysfunction; it occurred in 64 patients (46 mitral and 18 aortic) at a mean postoperative interval of 93 +/- 4 months (range 34 to 158). During the same period, 11 patients required reoperation for bioprosthetic endocarditis, 11 for paravalvular leak, and two for thrombosis. These patients are not included in this review. Reoperation for primary tissue failure was performed after a mean interval of 72 +/- 6 months (range 38 to 158) for patients with aortic bioprostheses and after 101 +/- 5 months (range 34 to 153) for those with mitral bioprostheses (p less than 0.05). Overall mortality at reoperation was 12.5%: 11% for the mitral group and 16% for the aortic group. In 62 patients (45 mitral and 17 aortic) primary tissue failure was caused by calcification of the cusps, associated with severe fibrous tissue overgrowth in seven. Bioprosthetic failure was caused by an intracuspal hematoma in one patient with mitral valve replacement and by lipid infiltration of the cusps in one patient with aortic valve replacement. Actuarial freedom from bioprosthetic primary tissue failure at 12 years is 61% +/- 5% for the mitral group and 69% +/- 7% for the aortic group. On the basis of our long-term follow-up of patients after mitral or aortic replacement with a porcine bioprosthesis, we conclude: primary tissue failure is the most frequent indication for reoperation in patients with a porcine bioprosthesis; calcification of the cusp tissue is the leading cause of primary tissue failure; reoperation for primary tissue failure may be a major concern, although mortality for elective cases is low; and the limited durability of porcine bioprostheses suggests their use be restricted to selected patients.

Animals↗
PubMed1984

[Not Available].

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Historiography↗