Search PubMed⌕ Search

Biomedical subjects

F Tronc

Publications and source records attributed to F Tronc.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Left ventricular assistance by postoperative mechanical devices in neonates].

Circulatory assistance in children and neonates has not been extensively reported. It poses specific problems related mainly to miniaturisation of systems. The authors report three cases of left ventricular assistance with the Biomedicus centrifugal pump followed by functional recovery in neonates operated for d-transposition of the great arteries. The assistance was installed by cannulation of the left atrial appendage and the ascending aorta, the canules being connected to the Biomedicus pump. The duration of assistance was 53, 116 and 120 hours respectively. The beginning of left ventricular recovery was observed after 24, 48 and 70 hours of assistance and the patients were weaned of assistance under stable haemodynamic conditions. One of the major problems during the period of assistance is decoagulation, 2 out of 3 patients requiring removal of thrombi during the first 12 hours of assistance. On the other hand, no cases of systemic embolism or thrombosis in the pump itself were observed. Decoagulation was maintained by continuous intravenous heparin with an initial dosage of 5 U/kg/h adapted to the activated cephalin time and anti Xa levels measured every 6 hours. No infectious complication was observed and the sternal wound healed satisfactorily despite systematic delayed closure of the thorax. The quality of results requires cooperation of a surgical infrastructure used to techniques of circulatory assistance, a well equipped neonatal intensive care unit and a permanently accessible laboratory for monitoring coagulation status.

Cardiac Surgical Procedures↗
PubMed1997

[Coarctation of the aorta and its surgical treatment].

Coarctation or isthmic stenosis of the aorta is defined as an abnormal obstruction situated at the junction of the aortic arch and the descending aorta near the site of ligamentus arteriosus. It is a common malformation representing 5 to 7.5% of all congenital heart diseases. Coarctation of the aorta is 2 to 3 times commoner in boys than in girls. Two clinical forms may be distinguished: asymptomatic isolated coarctation of childhood, the surgical treatment of which was first performed by Crafoord in 1944, and coarctation of the neonate and infant associated in over 2/3 of cases with other cardiovascular malformations, especially tubular hypoplasia of the aortic arch. The surgical correction of isolated coarctation is best performed between 6 months and 1 year of age in other to limit the incidence of residual hypertension. A modified Crafoord technique decreases the risk of restenosis and enables treatment of associated hypoplasia of the aortic arch in the same surgical procedure.

Adult↗
PubMed1996

Long-term results of heart transplantation deteriorate more rapidly in patients over 60 years of age.

It is generally agreed that the upper age limit for heart transplantation is 60 years. However, an increasing number of elderly candidates are accepted for heart transplantation. We retrospectively analyzed our experience with a total of 204 consecutive transplantations, performed in 195 adult patients (9 retransplantations) between March 1987 and September 1993. There were 48 patients older than 60 years (mean 62.9 +/- 3), group I (gr I) and 156 patients between 20 and 59 years old (mean 47.5 +/- 8), group II (gr II). The two groups were matched for sex-ratio (female 10.4 vs 14.2%), indications (cardiomyopathy, ischemic, others), and hemodynamic parameters (pulmonary artery pressure, capillary wedge pressure, cardiac index). A ventricular assist device was used in 14 patients as bridge to transplantation in gr II vs 0 to gr I. There were seven early deaths in gr I (14.6%) vs 14 in gr II (8.97%, NS). A total of 183 survivors (41 vs 142) have been followed up for 1 month-6.3 years (mean follow-up 20.4 +/- 19.3 months in gr I, 35.4 +/- 23 in gr II). No patient was lost to follow-up. There were 11 late deaths in gr I vs 16 in gr II. The most common cause was malignancy (n = 4) in gr I and sudden death (n = 9) in gr II, with a significant difference. The actuarial survival was 68.8% in gr I vs 88.5% in gr II at 1 year 43.5% in gr I vs 76.4% in gr II at 5 years. In conclusion, transplanted patients over 60 years of age have a significantly poorer late survival than younger patients, despite similar good early results. Moreover, the causes of late deaths were different in the two groups. So, heart transplantation in patients over 60 years of age should be carefully considered.

Adult↗
PubMed1996

Primary melanoma of the heart: case report of an association with coronary stenosis.

A 63-year-old man presented with unstable angina. The coronary angiogram revealed a proximal left anterior descending artery (LAD) stenosis and an irregularity on the anterior wall of the left ventricle. Intraoperatively, a malignant melanoma, independent of the coronary stenosis, was identified and resected, and an internal mammary graft was inserted. No primary tumor was found. The patient is alive 18 months after operation, with a normal magnetic resonance imaging (MRI), which seems to be the technique of choice for following-up heart melanomas.

Coronary Disease↗
PubMed1996

Role of NO in flow-induced remodeling of the rabbit common carotid artery.

Flow-induced changes in vessel caliber tend to restore baseline wall shear stress (WSS) and have been reported to be endothelium-dependent. To investigate the role of endothelium-derived nitric oxide (NO) in the adaptive increase in artery diameter in response to a chronic increase in blood flow, an arteriovenous fistula was constructed between the left common carotid artery (CCA) and the external jugular vein in 22 New Zealand White rabbits, and NO synthesis was inhibited in 14 animals by long-term administration of NG-nitro-L-arginine-methyl ester (L-NAME) in drinking water given for 4 weeks. The remaining 8 animals served as controls. Mean arterial blood pressure was not significantly altered by L-NAME treatment (91 +/- 2 in control versus 98 +/- 3 mm Hg in L-NAME-treated rabbits). Blood flow significantly increased in the left CCA in both groups but was lower in L-NAME-treated than control animals (106.1 +/- 10.7 versus 196.2 +/- 32.3 mL/min, P < .003). The diameter of the flow-loaded left CCA also increased significantly in both groups compared with the right CCA (2.15 +/- 0.12 and 2.54 +/- 0.1 mm, respectively, P < .02), but the increase was less in the L-NAME-treated than the control group (3.24 +/- 0.09 and 4.64 +/- 0.17 mm, respectively, P < .0001). The diameter of the anastomosed veins was also increased but to a much lesser degree in L-NAME-treated animals than in controls (4.14 +/- 0.29 versus 7.94 +/- 0.51 mm, P < .0001). As a result of artery enlargement, WSS was normalized in the flow-loaded left CCA of the control group (8.87 +/- 0.77 dynes/cm2) regardless of blood flow values. In L-NAME-treated animals, however, WSS was only partially regulated, the mean value being significantly increased (18.7 +/- 2.2 dynes/cm2, P < .006). Moreover, a highly significant positive correlation between WSS and blood flow was obtained in L-NAME-treated animals (r = .84, P < .0001). We also found remodeling of the artery wall, with a larger increase in the medial cross-sectional area associated with an increased number of smooth muscle cells, in the control group compared with the L-NAME-treated group (0.75 +/- 0.09 versus 0.49 +/- 0.04 mm2 and 4504 +/- 722 versus 2717 +/- 282 cells/mm2, P < .03). We conclude that NO plays a role in the increase of vessel caliber in response to chronic increase in blood flow. As yet unidentified additional metabolic processes appear to be necessary for a complete regulatory response.

Administration, Oral↗
PubMed1994

Retrograde warm blood cardioplegia preserves hypertrophied myocardium: a clinical study.

The ability of retrograde warm blood cardioplegia to preserve hypertrophied myocardium remains controversial. This two-part study was undertaken to address this question in patients subjected to aortic valve replacement for calcified aortic valve stenosis complicated with echocardiographically defined left ventricular hypertrophy. Part 1 was designed to assess the intraoperative patterns of myocardial oxidative metabolism in 20 patients in whom the severity of left ventricular hypertrophy was reflected by a mean (+/- standard error of the mean) myocardial mass index of 213 +/- 15 g/m2. After antegrade arrest, warm blood cardioplegia was continuously given through the coronary sinus at a flow rate of 200 +/- 5 mL/min. The use of a low-dilution cardioplegia delivery technique enabled us to keep hematocrit at 25.6% +/- 0.9% and the core temperature was allowed to drift to 32.7 +/- 0.2 degrees C. At the end of the arrest period, blood samples were simultaneously taken from inflow (coronary sinus catheter) and outflow (left coronary ostium) cardioplegia and assayed for blood gases, oxygen content and saturation and lactate. Part II was designed to compare the clinical outcomes of these 20 warm patients with those of 20 case-matched patients in whom a conventional hypothermic myocardial protection technique was used. The results of part I show that after an average arrest period of 72 +/- 4 minutes, the residual oxygen demand was still high as reflected by a percent oxygen extraction of 34.8% +/- 4.1%. This demand, however, was adequately met by the supply, as demonstrated by (1) the absence of transmyocardial acid production, (2) a negligible release (outflow minus inflow) of lactate (0.28 +/- 0.1 mmol/L), and (3) a high residual oxygen saturation (65.7% +/- 3.8%) in outflow cardioplegia. The results of part II show that the clinical outcomes of warm patients were overall good and not different from those of the cold group. We conclude that retrograde warm blood cardioplegia can adequately preserve hypertrophied myocardium by keeping its metabolism predominantly aerobic during aortic cross-clamping provided that measures are taken to optimize the determinants of the oxygen demand/supply ratio throughout. These measures include avoidance of left ventricular distention, immediate ablation of any recurring activity during arrest, maintenance of high retrograde flow rates, limitation of hemodilution, and uninterrupted mode of cardioplegia delivery.

Acids↗
PubMed1994

Does normothermia during cardiopulmonary bypass increase neutrophil-endothelium interactions?

BACKGROUND: The use of warm blood cardioplegia is usually associated with that of warm cardiopulmonary bypass (CPB). Little is known, however, about the effect of temperature during bypass on neutrophil-endothelium interactions, which are currently considered a key component of the inflammatory response to CPB. METHODS AND RESULTS: Twenty-five patients operated on under CPB were studied. Core temperature during bypass was kept normothermic (33.5 degrees C to 37 degrees C) in 14 and lowered to 28 degrees C to 30 degrees C in the 11 remaining patients. The two groups were otherwise comparable. Arterial blood samples were collected before CPB and 30 minutes, 4 hours, and 24 hours thereafter. Samples were assayed for interleukin-1 receptor antagonist (IL-1ra), soluble intercellular adhesion molecule 1 (sICAM-1), and elastase, which are markers of cytokine production, cytokine-upregulated endothelial ligands for neutrophil adhesion molecules, and degranulation secondary to adhesion of neutrophils to endothelial cells, respectively. IL-1ra levels (mean +/- SEM) peaked 4 hours after bypass and were significantly higher in the warm group (87,926 +/- 24,067 versus 18,090 +/- 5798 mg/L, P < .02). Peak values of sICAM-1, which occurred 24 hours after bypass, were correspondingly higher in warm patients (414 +/- 74 versus 298 +/- 23 micrograms/L in cold patients). In keeping with these data, warm patients released significantly more elastase at both the 30-minute (703 +/- 101 versus 349 +/- 55 micrograms/L, P < .01) and 4-hour (627 +/- 116 versus 324 +/- 31 micrograms/L, P < .03) post-CPB study points. CONCLUSIONS: Temperature profoundly affects neutrophil-endothelium interactions, which leads one to question the use of systemic normothermia in patients at higher risk of suffering from postbypass inflammation-mediated organ damage.

Body Temperature↗
PubMed1993

Pentoxifylline decreases cyclosporine-induced renal endothelin release and vasoconstriction.

Cyclosporine (CSA) causes an acute vasoconstriction of renal artery and a significant increase in renal endothelin release. Pentoxifylline, a vasodilator, has been suggested to prevent CSA toxicity. To study the effect of pentoxifylline treatment on CSA-related vasoconstriction and endothelin release, a model of renal autoperfusion in the dog was used. Oral pentoxifylline at the dose of 400 mg three times daily for 3 days was given to 15 dogs. Pure powder CSA (10 mg) was injected into the isolated renal artery perfused at constant flow; changes in perfusion pressure reflected variations in vascular resistance. In the pentoxifylline-treated group (15 dogs), the infusion of CSA caused an average increase of 27 +/- 8 mm Hg in renal perfusion pressure, compared with 60 +/- 10 mm Hg in a control group of 8 untreated animals (p < or = 0.05). Plasma concentration of endothelin in the renal vein increased from an average of 1.2 +/- 0.2 pg/mL before to 2.4 +/- 0.5 pg/mL after CSA administration (p < or = 0.05) in the control group, whereas it did not change significantly in the pentoxifylline-treated group. Thus, oral pretreatment with pentoxifylline significantly decreased the renal vasoconstriction and endothelin release due to CSA administration.

Animals↗
PubMed1993

Blockade of cyclosporine-induced vasoconstriction by the calcium channel blocker diltiazem in dogs.

The calcium channel blocker diltiazem has been shown to reduce cyclosporine toxicity both in clinical and in experimental studies. To determine the effect of diltiazem administration on cyclosporine vasoconstriction and on renal release of endothelin, we administered cyclosporine in models of renal and hind limb autoperfusion in the dog. Infusion of cyclosporine in the hind limb (20 mg) during diltiazem perfusion caused an average increase of 6 +/- 2 mm Hg in hind limb perfusion pressure compared with 17 +/- 2 mm Hg before diltiazem, a significant difference (p < 0.05). Similarly, injections of cyclosporine (10 mg) in the kidney during diltiazem infusion caused an average increase of 26 +/- 4 mm Hg in renal perfusion pressure compared with 83 +/- 13 mm Hg before diltiazem infusion, a significant decrease in the renal vascular response (p < 0.05). On the other hand, sodium nitroprusside did not change the renal vasoconstriction to cyclosporine, which suggests a specific effect of diltiazem. Serum levels of endothelin in renal venous blood increased from 0.5 +/- 0.4 pg/ml to 3.8 +/- 0.6 pg/ml with cyclosporine, despite diltiazem infusion. Therefore, although the calcium channel blocker diltiazem effectively decreases cyclosporine-induced renal and hind limb vasoconstriction, it does not act by preventing endothelin release induced by cyclosporine stimulation.

Animals↗
PubMed1992

Effect of internal mammary artery dissection on sternal vascularization.

Internal mammary artery (IMA) dissection may cause sternal devascularization and ischemia resulting in sternal wound complication. To evaluate the effect of median sternotomy and IMA dissection on sternal vascular supply, sternal bone tomography was performed 7 days and 1 month after cardiac operation in 67 patients. Seventeen nondiabetic patients had single IMA grafts, 18 had double IMA grafts, and 12 had only saphenous vein grafts or valve replacement. Twenty diabetic patients were studied after any one of these operations. Seven patients were restudied 1 month after the operation. Sternal technetium-99m-methylene diphosphate tomography was performed. The sternum was visualized and focal zones of hypoactivity represented sternal hypoperfusion. The ratio of hypoactivity area over total sternal area was calculated for every patient. After median sternotomy without single or double IMA grafts, the averaged hypoperfusion ratio was 4% +/- 1% compared with 13% +/- 3% after single IMA grafts and 24% +/- 6% after double IMA grafts (p less than 0.0001). Diabetic patients without IMA, with single IMA, and with double IMAs showed hypoperfusion areas of 5% +/- 3%, 15% +/- 5%, and 23% +/- 9%, respectively, a result similar to that of nondiabetic patients. One month after operation the hypoperfusion area decreased to 2% +/- 2% (p less than 0.05) in restudied patients. Our results indicate that IMA dissection causes a significant although partial and temporary sternal ischemia, which is more severe after double IMA than single IMA mobilization and which may be incriminated in the development of sternal wound infection. This vascularization defect was not greater among patients with diabetes mellitus.

Body Mass Index↗
PubMed1992

Mechanism of hind limb vasoconstriction due to cyclosporin A in the dog.

Cyclosporin A (CSA) causes an acute vasoconstriction of hind limb arterial vessels. To determine the mechanism of action of CSA on the peripheral arterial bed, studies were performed on the isolated femoral artery perfused at constant flow in 61 dogs. Changes in femoral perfusion pressure reflected variations in vascular resistance. Pure powder CSA was dissolved in autologous blood and injected at doses of 1, 5, 10, and 20 mg. Infusions of 1 and 5 mg CSA caused nonsignificant mean increases of 4 +/- 2 mm Hg (95% confidence interval [CI], 0-8; p > 0.05) and 10 +/- 4 mm Hg (95% CI, 0-21; p > 0.05) in femoral perfusion pressure, with CSA blood levels in the femoral vein averaging 40 +/- 16 and 126 +/- 50 nmol/l, respectively, at the end of the injections. Infusions of 10 and 20 mg CSA caused significant increases in femoral perfusion pressure averaging of 8 +/- 3 mm Hg (95% CI, 1-14; p < 0.05) and 20 +/- 4 mm Hg (95% CI, 11-29; p < 0.05) in femoral perfusion pressure. CSA blood levels at the end of injections averaged 271 +/- 99 and 431 +/- 146 nmol/l, respectively, in the femoral vein. Blockade of alpha-adrenergic receptors with phentolamine and surgical lumbar sympathectomy decreased significantly the CSA vasoconstrictive effect in peripheral arterial vessels, with increases in perfusion pressure averaging 29 +/- 5 mm Hg before and 14 +/- 3 mm Hg after phentolamine (p < 0.05) and 30 +/- 2 mm Hg before and 8 +/- 2 mm Hg after sympathectomy (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1992

[Traumatic double rupture of the isthmic aorta. Apropos of an unrecognised case successfully treated by two-stage surgery].

The authors report the case of a 33 year old patient, who underwent an emergency repair of a traumatic tear of the thoracic aorta, after a car accident. This operation was carried out with femoro-femoral cardiopulmonary bypass support. Associated lesions were traumatic tear of the left diaphragm repaired through left thoracotomy during repair of the aorta, rupture of the liver and multiple fractures of the left superior limb. Postoperative course was marked by liver hemorrhage and septicemia. Orthopedic treatment of the various fractures was performed. The course of thoracic lesions was uneventful. An aneurysm of the aortic isthmus was revealed during venous digital subtraction angiography routinely performed 60 days after surgery. The patient was reoperated with femoro-femoral bypass support. A second incomplete tear of the aorta, missed during the first operation was discovered 3 cm above the suture of the first one. This lesion was easily repaired and the post-operative course was uneventful. The value of systematic control angiography after aortic traumatic repair is emphasised.

Adult↗
PubMed1992

[Late revascularization of the renal artery: what are the prognostic criteria?].

Two patients with non functioning silent kidney on excretory urography and renal artery occlusion on angiography, underwent renal artery revascularization without severe hypertension or renal failure. Angiographic appearance of collateral circulation, histologic evidence of intact viable glomeruli and a normal sized kidney are necessary for successful results. Renal blood flow was restored in the two patients but one had slight return of function and the other patient showed no evidence of improvement. Both patients presented criteria for revascularization. The first case was a minor success on the renal scintigraphy. The return of renal function did not occur in the second case because of preexisting renal pathology. We therefore recommend histologic examination before every renal artery revascularization for chronic occlusion.

Angiography↗
PubMed1991

Dose-dependent effect of cyclosporin on renal arterial resistance in dogs.

Important side effects of cyclosporin (CSA) are renal insufficiency and hypertension. They might be related to a renal vasoconstrictive effect of CSA, and this vascular response might be due to a local mechanism. CSA was injected in isolated renal artery perfused at constant flow in dogs. Changes in renal perfusion pressure reflected variations in vascular resistance. Pure CSA was dissolved in autologous blood and injected at doses of 0.5, 1, 5, and 10 mg. The infusion of 0.5 and 1 mg caused averaged renal perfusion pressure increases of 8 +/- 4 mmHg and 15 +/- 8 mmHg. Renal venous CSA levels averaged 32 +/- 3 and 49 +/- 9 nmol/l, respectively, at the end of injections. Infusion of 5 and 10 mg of CSA caused averaged renal perfusion pressure increases of 32 +/- 12 mmHg and 81 +/- 21 mmHg. Renal venous CSA levels at the end of injections averaged 142 +/- 30 and 382 +/- 82 nmol/l, respectively. A positive correlation was found between the changes in renal perfusion pressure and renal venous CSA levels. Blockade of alpha-adrenergic receptors, surgical renal sympathectomy, administration of thromboxane receptor antagonist, and endothelial-dependent vasodilation by acetylcholine infusion did not affect the renal vasoconstriction effect of CSA; renal response to CSA was prevented by blockade of the Ca channels with diltiazem, and the plasma endothelin concentration in renal venous blood increased significantly after injection of CSA. A dose-dependent increase in renal arterial resistance occurs with therapeutic blood levels of CSA. Renal vasoconstriction is induced by a local effect at the arterial wall, which is independent of neurogenic, adrenergic, and prostaglandin mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Effect of therapeutic doses of cyclosporine injected into the renal and femoral arteries in dogs].

Cyclosporine is the core component of all immunosuppressive protocols. Renal insufficiency and hypertension are the two major side effects of cyclosporine use. A vascular effect of cyclosporine could explain these complications. To study the effect of cyclosporine on vessel wall, a model of isolated renal and femoral artery perfusion was used in the dog. The injection of 0.5, 1, 5 and 10 mg of cyclosporine in the renal artery caused an average increase in renal perfusion pressure of 8 +/- 4, 15 +/- 8, 32 +/- 12 and 81 +/- 21 mmHg (p less than 0.05) respectively. Blockade of alpha-adrenergic receptors and renal sympathectomy did not modify the renal vascular response to cyclosporine. The injection of 1, 5, 10 and 20 mg of cyclosporine in the femoral artery caused an average increase in perfusion pressure of 4 +/- 2, 10 +/- 4, 9 +/- 2 and 20 +/- 8 mmHg (p less than 0.05) respectively. Blockade of alpha-adrenergic receptors and lumbar sympathectomy prevented the vasoconstrictive effect of cyclosporine on the femoral artery. Therefore, cyclosporine caused a significant increase in renal perfusion pressure and a modest vasoconstriction of the femoral artery. This effect appears to be related to an adrenergic mechanism only in the femoral circulation. We conclude that other studies are needed to define the mechanism responsible for the vasoconstrictive effect of cyclosporine.

Animals↗
PubMed1991

[The superior mesenteric artery syndrome. Apropos of a case and review of the literature].

During laparotomy for an appendicular peritonitis, the authors found an acute mesenteric artery syndrome. Conservative treatment consisted of mobilisation of the 4th part of the duodenum with section of the suspensory muscle of Treitz, but this was not sufficient to cure the patient. Two weeks later the patient completely recovered after a duodenojejunal anastomosis. A review of the literature confirmed that surgical treatment for scoliosis and anorexia nervosa play an important role in the aetiology of this disease.

Adult↗
PubMed1989

[The CHARGE association].

The CHARGE association includes a group of several malformations, and always a coloboma and/or choanal atresia. We present 8 cases of this syndrome, 5 complete and 3 incomplete forms. Prognosis at term seems severe, considering the visceral malformations (namely cardiac) and the cerebral handicap often associated. In most cases the CHARGE association is a sporadic event; however, one cannot exclude the possibility that certain forms follow a Mendelian pattern of inheritance. The mechanisms leading to this association have not yet been elucidated: it is probably due to migration abnormalities of the neural crests as in the VATER association of Di George syndrome.

Abnormalities, Multiple↗