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Biomedical subjects

A Carpentier

Publications and source records attributed to A Carpentier.

At least 325 records · Page 18Linked to original sources
PubMed1982

[Clinical study of prostacyclin in extracorporeal circulation. Effects on hemodynamics and coagulation].

The effects of prostacycline (PGI2), the most powerful known platelet antiaggregant on platelet count and function during cardiopulmonary bypass, were assessed in a double blind study. One group of 13 patients received 2,5 mg/Kg of Heparin with an infusion of 25 ng/Kg/min of prostacycline instituted 15 minutes before the Heparin, continued at the beginning of cardiopulmonary bypass at a dose of 50 ng/Kg/min and terminated at the end of bypass. A second group of 15 patients were studied by the same protocol with a placebo infusion. The platelet count was significantly higher at the end of cardiopulmonary bypass in the Prostacycline group. Platelet aggregation was reduced by comparison with the control group from the beginning of Prostacycline infusion. The active thrombin time was significantly longer in the Prostacycline group. However, blood loss did not differ significantly between the two groups although it was less in the study group. The platelet count and function during cardiopulmonary bypass with Prostacycline was therefore increased and resulted in a reduction in Heparin consumption.

Anticoagulants↗
PubMed1982

Structural changes of glutaraldehyde- treated porcine bioprosthetic valves.

Gross anatomic, histologic, and transmission and scanning electron microscopic observations were made of 29 bioprosthetic valves that had been implanted in patients for up to 115 months. On the basis of these morphologic data, no significant evidence of tissue rejection was seen. However, the durability of these valve bioprostheses is still questionable. Our observation primarily emphasize three factors: (1) disruption of the endothelial cell barrier and the lack of significant host endothelialization even 115 months after transplantation; (2) increased permeability that eased diffusion of circulating host plasma proteins into valve tissue, and increased activity of infiltration processes, eg. calcification and lipid accumulation; and (3) biodegradation of the collagen framework. Each of these factors may contribute further to valve dysfunction. Development of an intimal fibrous sheath seems to occur in porcine bioprostheses that have been implanted for the longest periods of time, but the rate of host tissue ingrowth varies.

Adolescent↗
PubMed1982

Hemodynamic and metabolic effects of prostacyclin after coronary bypass surgery.

The hemodynamic and metabolic effects of prostacyclin (PGI2) were assessed in 12 patients who underwent coronary bypass surgery. PGI2 were injected intravenously at a rate of 2.5 ng/kg/min for 10 minutes, followed by three consecutive 10-minute injections of 5, 10 and 20 ng/kg/min. PGI2 infusion decreased systolic and diastolic arterial pressures by 17% (p less than 0.001) and increased cardiac index by 17% (p less than 0.001) without changing the heart rate. Right atrial, pulmonary arterial and pulmonary wedge pressures remained essentially unchanged. Total vascular resistance decreased by 37% (p less than 0.001). Rate-pressure product, an index of myocardial oxygen consumption, decreased by 13% (p less than 0.01), while stroke work index did not change. A 36% decrease in arterial PO2 (p less than 0.001) was the most consistent metabolic effect induced by PGI2 infusion. However, oxygen transport increased by 11% (p less than 0.05), suggesting that no decrease in peripheral oxygen supply was produced. Thus, PGI2 improved cardiac function and performance by a predominant effect on total vascular resistance. It may be valuable in the management of patients who undergo coronary artery surgery.

Adult↗
PubMed1982

Calcifications of cardiac valve bioprostheses. Biochemical, histologic, and ultrastructural observations in a subcutaneous implantation model system.

To study the process of calcification in bioprosthesis, 108 glutaraldehyde-treated porcine aortic valve leaflets were implanted subcutaneously in rabbits and removed 1 day to 6 months later; morphologic findings were correlated with biochemically determined levels of calcium (Ca++) and gamma-carboxyglutamic acid (Gla), a vitamin K-dependent Ca++-binding amino acid known to be present in a variety of tissues with pathological calcification. Gla and Ca++ levels began to increase about 2 months after implantation and increased progressively with time. Ca/Gla molar ratios were comparable to those in leaflets of bioprostheses explanted from patients, 22 to 64 months after implantation. Morphologically evident calcification began at the same time that Gla and Ca++ increases were detected biochemically and also increased in severity with time. Electron microscopy showed that calcification primarily involved the surface of collagen fibrils and the interfibrillar spaces. The biochemical and morphological findings in this experimental system are similar to those described in calcified porcine bioprosthetic valve leaflets removed from patients, but occurred much more rapidly. As with pathological calcification of other tissues, progressive calcification was accompanied by increased Gla levels, suggesting that Gla plays a role in the calcification of the leaflets. This model allows rapid comparative evaluation of large numbers of valve leaflets maintained under similar host conditions.

1-Carboxyglutamic Acid↗
PubMed1981

[Coronary surgery combined with peripheral vascular surgery. Apropos of 10 cases].

Coronary artery surgery may be envisaged in the context of diffuse arterial disease, especially in association with lesions of the cerebral and lower limb axes. The object of this paper is to advance the concept of coronary surgery coupled with peripheral vascular surgery. Ten patients underwent double revascularisation (coronary and peripheral vessels) between 1977 and 1979. In Group I (5 patients) coronary surgery was coupled with simultaneous cerebral revascularisation (1 aorto-brachiocephalic bypass and 4 endarterectomies). Group II comprised 5 patients undergoing simultaneous coronary and aorto-bifemoral bypass surgery. No operative deaths or serious complications were observed in this short series. The practical conclusions are in favour of widening the indications for simultaneous coronary and cerebral revascularisation. However, the indications for coronary surgery coupled with lower limb revascularisation must be precise and, therefore, more limited.

Aged↗
PubMed1981

[Atrioventricular discordance. Results of a series of 34 operations].

From 1968 to 1980, 34 patients with atrioventricular discordance underwent intracardiac repair. Thirty three patients had a ventriculoarterial discordance (corrected transposition) and one patient had a double outlet right ventricle. The age at operation ranged from 12 months to 59 years (mean 19 years). The lesions were ventricular septal defect (26 cases), pulmonary stenosis (22 cases), atrioventricular valve anomalies (20 cases). Lesions were associated in 80% of the cases. Ventricular septal defect and pulmonary stenosis were combined in eleven patients. Seven patients had had palliative operations. Pulmonary stenosis was mostly of subvalvular type and treated with a conduit. A patient with double outlet right ventricle and pulmonary atresia had a conduit on the left pulmonary artery because the right one was non-functional. Ventricular septal defects were closed through the right A-V valve, and the stitches placed on the free edge of the defect. The tricuspid valve (systemic) was replaced in 10 cases. Hospital mortality was 38% but only 3 out of 14 (21,4%) patients operated upon since 1975 have died. Late mortality was 24% (5 patients) related to conduction problems in 3 patients. Three patients were reoperated with good results. Out of twelve patients with a long-term follow-up, eleven have a good functional result. 7 patients with preoperative A-V block and 3 patients with atrial fibrillation had pacemakers implanted. 16 patients had postoperative A-V block. The incidence of conduction problems is now reduced with the use of conduit for subvalvular pulmonary stenosis.

Adolescent↗
PubMed1981

New surgical approach to aortic dissection: flow reversal and thromboexclusion.

With the aim of decreasing the complications and mortality associated with the current techniques for aortic dissections, we have developed an operation which consists of bypassing the dissected aorta and creating flow reversal in the dissected segment. Seven patients with either acute (five) or chronic aortic dissections (two) were operated upon successfully, with no early or late deaths. Three transient postoperative complications were encountered: low cardiac output, hemiparesis, and renal insufficiency. Postoperative arteriography was performed in five patients and demonstrated exclusion of the dissected lesions by thrombosis following flow reversal in the descending aorta. Follow-up is available from 2 to 28 months (average 13 months), with no long-term complications.

Adult↗
PubMed1981

Cytotoxicity of cardioplegic solutions: evaluation by tissue culture.

Numerous cardioplegic solutions have been proposed for myocardial protection during open heart surgery. Their effectiveness has been evaluated by hemodynamic, enzymatic and histologic studies, but the cytotoxicity of these solutions has never been assessed. Human fibroblasts and endothelial cells in tissue culture were incubated for 3 hours at 19 degrees C in 12 of the most commonly used cardioplegic solutions. The solutions were then removed and replaced by tissue culture medium at 37 degrees C. The cytotoxicity of the solution was evaluated by staining the cells with trypan blue after 3 hours and 24 hours. The percentage of dead cells varied from 2--21%. Temperature and addition of blood to the various solutions significantly influenced cytotoxicity. Cardioplegic solutions appear to have different toxicity levels when tested in tissue culture.

Anti-Arrhythmia Agents↗
PubMed1981

Surgical treatment of constrictive fibrous endocarditis.

Between 1971 and 1980, 20 patients with fibrous endocarditis were treated by resection of ventricular endocardium and replacement of the atrioventricular valve. There were 13 male and seven female patients whose ages ranged between 12 and 58 years. Thirteen were white and the remaining seven were black Africans. Nine presented a right-sided form, five a left-sided one, and six presented involvement of both ventricles. The role of hypereosinophilia is discussed in the etiology of the disease. The operation was performed according to the techniques we had developed in our first operative case-excision of the atrioventricular valve. Complete resection of the endocardium, and valvular replacement. There were three operative deaths. Complete atrioventricular dissociation was observed in seven of our patients. particularly in those with right-sided endocarditis. At late follow-up, we have not observed any case of recurrence of the disease. On the basis of our experience and the results previously published in the literature, we believe that endocardiectomy is the best current treatment of this disease.

Adolescent↗
PubMed1980

Valvular xenograft and valvular xenobioprosthesis: Past, present, and future.

At the present time, glutaraldehyde-preserved porcine valves appear to be a reasonable alternative in valvular replacement. The expected durability limit of 8-15 years with the models currently commercially available is counterbalanced by a lower risk of acute complications; particularly thromboembolism. This allows the patient to be free from drugs and related problems. Our opinion is that the patient should take part in choosing between a bioprosthesis and a mechanical prosthesis. This critical choice will depend upon the relative importance for each individual of an improved quality of life with a bioprosthesis versus a lower risk of reoperation with a mechanical valve.

Aortic Valve↗
PubMed1980

[Long term hemodynamic results following complete cure of Fallot's tetralogy].

Cardiac catheterisation was carried out on an unselected series of 148 patients who had undergone complete correction of Fallot's tetralogy after an average postoperative period of si and a half years (range 2 to 20 years). 4% residual significant interventricular shunts (Qp/Qs > 1.3), 11% residual stenosis on the infundibulo-pulmonary tract (gradient greater than or equal to 10 mmHg) and 60% pulmonary incompetence was found. These findings do not reflect the excellent clinical results. All patients had normal lives: 89% remain asymptomatic since their operation and symptoms in the other patients are limited to moderate dyspnoea on effort or to arrhythmias which are usually periodic. A synthesis of the clinical and haemodynamic data shows that only a quarter of patients may be considered to be cured, that although the surgical results in 2/3 patients are not perfect, they are satisfactory, and that the results of complete correction in the remaining 12% are poor. The results do not appear to be related to the age at which correction was performed or to previous palliative surgery. On the other hand, the long-term haemodynamic results were related to the surgical method of infundibulo-pulmonary repair. Systolic right ventricular pressures of over 60 mmHg recorded at the end of operation in 33 patients, had returned to normal in 76% cases. These results suggest that the indications for prosthetic remodeling of the infundibulo-pulmonary tract should be increased, although this does not always prevent residual stenosis.

Adolescent↗