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Biomedical subjects

I Gallo

Publications and source records attributed to I Gallo.

At least 19 recordsLinked to original sources
PubMed2001

Failure of stavudine-lamivudine combination therapy in antiretroviral-naive patients with AZT-like HIV-1 resistance mutations.

To analyze the clinical relevance of AZT resistance mutations in AZT-naive patients, 56 HIV-1 seropositive patients treated for 18 months with stavudine/lamivudine (27 patients) or AZT/lamivudine (29 patients) were studied. AZT-like resistance mutations were found in 13 out of 29 (44%) patients treated with AZT/lamivudine and in 11 out of 27 (40%) patients treated with stavudine/lamivudine. No stavudine or multi-drug resistance mutations were detected. After 26 months of treatment more than 60% of patients showed a virological failure. Among 10 patients failing treatment with stavudine/lamivudine, 9 had AZT-like resistance mutations. The phenotypic test, performed on HIV-1 strains isolated from six of these nine patients, showed a resistance to AZT in five isolates and to stavudine in two isolates. The genotypic pattern of the latter two isolates showed the combined mutations M184V plus R211K and L214F. AZT-like resistance mutations in AZT-naive patients seem to correlate with a virological failure during long-term stavudine therapy.

Anti-HIV Agents↗
PubMed1998

[Coronary revascularization surgery with arterial grafts].

Coronary artery revascularization surgery is well established procedure throughout the world. The benefits are based on the blood perfusion through the implanted grafts distal to the coronary occlusions and continue as long as the grafts remains patent. The immediate success of this procedure is related to the surgical technique and the anatomical characteristics of the grafted coronary arteries. However, the long term results are mainly dependent on the type of grafts used. The modern era of myocardial revascularization started in the sixties with the use of saphenous vein grafts by Johnson and Favaloro. Alternative vascular conduits to the saphenous vein have been tried, and the internal mammary artery has become the first choice. In recent years, various publications have demonstrated the supremacy of the internal mammary artery over the saphenous vein when used as a single, bilateral, sequential of free graft. In order to obtain full myocardial revascularization, the use of alternatives to the internal mammary artery is required. The gastroepiploic artery, the inferior epigastric artery and the radial artery have been used as alternatives to the saphenous vein with the hope of obtaining long term results similar to the internal mammary artery.

Arteries↗
PubMed1996

Heparin-coated circuit in coronary surgery. A clinical study.

We performed a randomized study in 101 patients who underwent routine isolated coronary bypass graft surgery. In 50 cases an entire coated Carmeda circuit was used (coated group), and an uncoated circuit in the remaining 51 (uncoated group). A Medtronic Maxima oxygenator and a Biomedicus Biohead were used in all cases. Patients with coated circuits received low systemic heparinization with a heparin loading dose of 200 IU/kg, and 300 IU/kg for the control. Activated coagulation time was maintained at more than 275 s for the coated group versus more than 400 s for the uncoated one. The mean age of patients was 64.1 +/- 9.6 for coated and 63.5 +/- 9.7 for the uncoated group. The number of coronary grafts was 3.1 +/- 0.7 for the coated group and 3.1 +/- 0.1 for the uncoated one. Cross-clamp and bypass times were 53 +/- 14 and 98 +/- 24 min for the coated, versus 57 +/- 15 and 104 +/- 24 for the uncoated, group. Chest drainage was 989.4 +/- 509.5 ml for the coated group versus 1435 +/- 1027 for the uncoated one (P < 0.02). The amount of transfused homologous blood was 723 +/- 597 ml for the coated group versus 1071 +/- 831 ml for the uncoated one (P < 0.03). Postoperative endotracheal intubation time was 12.1 +/- 3.6 h for the coated and 14.6 +/- 4.5 h for the uncoated group (P < 0.05). Bleeding required rethoracotomy in 1/50 of the coated group, and in 4/51 of the uncoated one. Hospital mortality was 1/50 in the coated, and 4/51 in the uncoated, group. In our preliminary experience, heparin coating of an extracorporeal circuit reduces post-operative blood loss and blood transfusions in routine coronary bypass operations.

Aged↗
PubMed1994

Early primary tissue failure of a Labcor bioprosthesis.

A 78-year-old woman underwent re-replacement of a 19mm Labcor bioprosthesis implanted in aortic position eighteen months earlier. The rupture of the free margin of one leaflet was found at reoperation. There was no apparent cause of this rupture.

Aged↗
PubMed1992

[Percutaneous mitral valvuloplasty. Immediate results with the 30 mm diameter dilatation balloon].

Percutaneous balloon dilatation of the mitral valve is a promising alternative to surgical treatment for patients with mitral stenosis. We analysed echocardiographic and haemodynamic results in 62 consecutive patients who underwent mitral dilatation with a big and one chamber balloon (30 mm diameter). The relationship between the dilatation balloon area and body surface was 4.2 (in 98% of patients it was bigger than 3.5). In the whole series we get significant improvements in the haemodynamic parameters and mitral areas (0.91 cm2 versus 1.78 cm2)(p < 0.005). According to the echocardiographic score, patients were divided in two groups. Good results (mitral area > 1.5 cm2, and final, valve area 50% greater than the initial area), were obtained in 93% of patients with a score of 8 or less, and in 45% of patients with a score bigger than 8. Seventy-five percent of patients with bad results (mitral area < 1.5 cm2) were in atrial fibrillation versus 37% of patients where we get a good results. Mortality of procedure was nulle, and two patients required surgery because of procedure failure for mitral insufficiency. We can conclude: percutaneous mitral valvuloplasty with single balloon is valid alternative, and good results can be expected if there is a good relationship between the area of balloon and patient's body-surface. The echocardiographic score and presence of atrial fibrillation can predict immediate results of this technique.

Adult↗
PubMed1991

Calcified constrictive pericarditis. Ultrasonic debridement.

A case of complete debridement of a calcified pericardium in a patient with constrictive pericarditis is reported. The use of an ultrasonic surgical aspirator facilitated disintegration of calcium without damaging the adherent epicardium and myocardium.

Aged↗
PubMed1991

In situ right gastroepiploic artery. A conduit for coronary revascularization.

The internal mammary artery is widely recognized as the graft of choice for coronary artery bypass grafting at present. Alternative conduits have been investigated in order to find other adequate long-term grafts. The right gastroepiploic artery has been recently used as a graft to bypass distal coronary vessels. From November 1989 to June 1990, we have implanted this artery in 46 cases. Pedicled grafts were implanted in 20 patients to the main right coronary artery, in 21 patients we grafted the right distal branches, in 3 patients the left anterior descending, and in 2 the circumflex branches. Mean grafts per patient were 3 in this series, with a mean of 2.2 arterial grafts per patient. One patient died in the early postoperative period. The remaining patients had an uncomplicated postoperative evolution. Thirteen patients underwent graft and coronary angiography. Direct or indirect graft patency was confirmed in all cases. The final important issue concerning the long-term patency of this graft will be solved in the future, but short-term patency rates of the right gastroepiploic artery can be anticipated when proper techniques are used.

Adult↗
PubMed1991

[Myocardial revascularization with the gastroepiploic artery. The initial experience].

The internal mammary artery is widely recognized as the graft of choice for coronary artery bypass grafting at present. Alternative conduits have been investigated in order to find other adequate long-term grafts. The right gastroepiploic artery has been recently used as a graft to bypass distal coronary vessels. From November 1989 to April 1990 we have implanted this artery in 33 cases (32 in situ and one free grafts). The pedicled grafts were implanted in 17 patients in the main right coronary artery, in 13 we grafted the right distal branches, in one the left anterior descending, and the circumflex branch in one. The free graft was implanted in the first diagonal. Mean grafts per patient was of three in this series, with a mean of 2 arterial grafts per patient. One patient died in the early postoperative period. The remaining patients had an uncomplicated postoperative period. Thirteen patients underwent graft and coronary angiography. Direct or indirect graft patency was confirmed in all cases. The final important issue concerning the long-term patency of this graft will be solved in the future, but short-term patency rates of the right gastroepiploic artery can be anticipated when proper techniques are used.

Adult↗
PubMed1990

In vivo experimental assessment of polytetrafluoroethylene trileaflet heart valve prosthesis.

This report summarizes the results of a series of experimental implantations of polytetrafluoroethylene valves in sheep. Twelve prostheses were implanted in the tricuspid position in weanling (3- to 4-month-old, 26 +/- 3 kg) sheep. The valve sizes were 23 mm (eight animals) and 25 mm (four animals). There were two early deaths, and the 10 survivors were killed in a stepwise manner to get a mineralization profile of the valve. There was one episode of acute thrombosis but no evidence of pulmonary thromboemboli in any animal. In all cases the leaflets were thin and unretracted, but in half of them one cusp or more were stiffened. One valve displayed a fixed outward eversion of the free margin of two leaflets. Macroscopic calcification was detected in seven specimens and always involved the commissural areas. Radiologic studies confirmed this calcium topography and revealed only one case of severe and diffuse mineralization. In most cases the cusps showed a grossly visible pannus that was thinner and less extensive than usually seen in bioprostheses. Examination with light microscopy disclosed a complete lack of infiltrating cells within the cuspal material (made of compact polytetrafluoroethylene). However, those parts of the prostheses made of expanded polytetrafluoroethylene (the material covering the valve frame and the sutures) did show infiltration by host cells and calcium. Mineralized lesions were of extrinsic type, involving fibrin and fibroelastic host tissue accumulated in the inflow aspect of the commissures. Examination with transmission electron microscopy disclosed electron-dense masses surrounded by an electron-lucent granular homogeneous material in areas of mineralization. The time-course evolution of the tissue calcium content shows a moderate mineralization rate (0.46 +/- 0.31 mg/gm of dry-weight material per week of follow-up) and a marginally significant positive correlation between calcium content and follow-up. Our results suggest that the polytetrafluoroethylene valves have a moderate overall calcification rate and that calcium deposits appear to be always related to the commissural region and to the presence of expanded polytetrafluoroethylene.

Animals↗
PubMed1988

Comparative study of primary tissue failure between porcine (Hancock and Carpentier-Edwards) and bovine pericardial (Ionescu-Shiley) bioprostheses in the aortic position at five- to nine-year follow-up.

Retrospective follow-up data on 458 consecutive patients who received a Hancock, Carpentier-Edwards (C-E) or Ionescu-Shiley (I-S) bioprosthesis in the aortic valve position between April 1978 and December 1981 are reviewed. A total of 461 valves (184 Hancock, 131 C-E and 146 I-S) were available for study of the incidence of primary tissue valve failure after 5 to 9 years of follow-up. Cumulative follow-up was 1,016 patient-years for patients with Hancock valve, 688 for the C-E and 767 for the I-S group. Of the 397 prostheses at risk (154 Hancock, 120 C-E and 123 I-S), 36 instances of primary tissue valve failure occurred (12 Hancock, 7 C-E and 17 I-S). On an actuarial basis, the calculated probability of freedom from primary tissue valve failure was 88 +/- 4% for the Hancock group, 87 +/- 6% for the C-E and 51 +/- 17% for the I-S at 9 years. The linear incidence of tissue valve failure was 1.2 failing valves per 100 patient-years for the Hancock group, 1 for the C-E and 2.2 for the I-S. In a cohort of patients older than 40 years of age at the time of valve replacement, the rate of freedom from primary failure was 98 +/- 1%, 87 +/- 9% and 44 +/- 22% for the Hancock, C-E and I-S groups, respectively, at 9 years. Comparison of actuarial curves disclosed a meaningful difference between the pericardial valve and the Hancock and C-E porcine bioprostheses at 9-year follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1988

Long-term performance of porcine heart valve bioprostheses.

To assess the results after long-term implantation of porcine bioprosthetic heart valves, 320 patients with 381 valves were retrospectively reviewed. This group included all patients receiving one such xenograft in the mitral or aortic position (or both) in our institution between June 1974 and December 1976. The patients had a follow-up of 9-11.5 years. Actuarial patient survival rats (hospital mortality excluded) were 85%-90% at 6 years and 68%-79% at 11.5 years. Thromboembolic episodes did not show any significant clustering over the first weeks or months, in fact, they appeared at a constant rate. Actuarial rates of freedom from thromboembolism were greater than 90% for aortic patients at 11.5 years and greater than 80% for mitral and mitroaortic patients at 11.5 years. The linearized rate of anticoagulant-related haemorrhage for the whole group of patients was 0.4 events/100 patient years with a related mortality of 0.2 events/100 patient years. Prosthetic valve endocarditis and paravalvular leak appeared at linearized rates of 0.6 (0.1 of related mortality) and 0.4 (0.1 of related mortality) events/100 patient years. Primary tissue valve failure constituted the most prevalent complication (82 cases) in the long term but did not significantly worsen patient survival. Actuarial rates of freedom from primary tissue failure were 91% +/- 2% at 6, and 40% +/- 14% at 11.5 years for mitral valves, and 95% +/- 4% at 6 and 64% +/- 6% at 11.5 years for aortic valves.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Incidence of primary tissue valve failure in porcine bioprosthetic heart valves.

This report provides retrospective follow-up data on 324 consecutive patients who received a Hancock-I porcine valve in the aortic or the mitral position, or in both positions, between June, 1974, and December, 1976. This analysis included 319 valves (193 mitral, 126 aortic) available for study of the incidence of primary tissue valve failure after 10 to 12.5 years of follow-up. Of the 319 prostheses at risk, 114 instances of primary tissue valve failure occurred. Seventy-three of the failed valves were in the mitral position, and 41 were in the aortic position. The calculated actuarial probability of freedom from primary tissue valve failure was 52 +/- 5% for the mitral and 58 +/- 6% for the aortic prostheses at 12.5 years of follow-up. For patients older than 40 years at the time of operation, the rate of freedom from primary failure was 68 +/- 8% and 55 +/- 6% for aortic and mitral prostheses, respectively, at 12.5 years. Comparison of both actuarial curves disclosed no meaningful difference. However, a tendency toward greater failure rate was observed in the mitral prosthesis group.

Adolescent↗
PubMed1988

Degenerative pathologic findings after long-term implantation of bovine pericardial bioprosthetic heart valves.

Degeneration of bioprosthetic heart valves constitutes the most important limitation to their long-term durability and the factor that avoids a wider clinical use of these devices. We studied 26 degenerated bovine pericardial valves that belong to a series of 55 prostheses explanted for various reasons. Age of the patients at implantation of the valve and other factors predisposing to primary tissue failure did not seem to significantly influence the results obtained. Mean implantation time was longer for aortic than for mitral valves (p less than 0.05). Also, the mode of failure was different for mitral and aortic prostheses. Tearing of one or more leaflets without mineralization was more frequent (p less than 0.0025) among mitral than among aortic specimens. Coverage of the valve cusps by a macroscopically visible host sheath was more extensive on the outflow than on the inflow aspect (p less than 0.0015 aortic valves; p less than 0.015 mitral valves). On radiological examination the majority of valves had diffuse and severe mineralized lesions. Collagen degeneration was the most frequent histologic lesion to be found in both mineralized and calcium-free valves. Calcification was also frequent and appeared as mineral deposits that extended between different collagen planes. Scanning electron microscopy revealed the almost complete lack of "endothelium-like" cover on any of the valves and exposure of the underlying fibrous components of the pericardial tissue in areas subjected to abrasion. Transmission electron microscopy confirmed the collagen degeneration and disclosed electron-dense microparticles (probably mineralized) both in the extracellular space and within degenerated host connective tissue cells.

Adult↗
PubMed1987

The behavior of pericardial versus porcine valve xenografts in the growing sheep model.

The comparative long-term behavior of the pericardial versus the porcine bioprostheses is not yet known. The need for long follow-up times to answer this question makes the growing sheep model an attractive alternative, given its ability to induce early valve degeneration. Sixty-three sheep, 12 to 16 weeks old, were operated on and received 39 porcine (11 Xenomedica, 10 Carpentier-Edwards S, nine Hancock I standard, and nine Hancock I T6-treated) and 24 pericardial (14 Mitroflow and 10 Ionescu-Shiley low profile) prostheses of clinical quality in the tricuspid position. Of the 52 operative survivors (32 received porcine valves and 20 received pericardial bioprostheses), six animals (five pericardial and one porcine) were eliminated because of bioprosthetic infection. Late sudden death before the scheduled killing occurred significantly more often (p less than 0.0001) in the pericardial (8/15 or 53%) than in the porcine group (1/31 or 3%). Calcium content of the explanted valves was significantly correlated with time in the pericardial group and the Xenomedica porcine prostheses (p less than 0.05) but not in the Hancock I and Carpentier-Edwards S valves, where it was only marginally significant (0.1 greater than p greater than 0.05). Linear regression analysis of tissue calcium content showed a similar slope for the pericardial group and Xenomedica porcine valves, in comparison with the remaining porcine valves. Comparison between the two lines using covariance analysis demonstrated a statistically significant difference between them, which shows that the pericardial and Xenomedica porcine valves appear to reach higher levels of calcification in a shorter follow-up time than the Hancock I, standard and T6-treated, and the Carpentier-Edwards S valve in this animal model.

Animals↗