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Biomedical subjects

P Nataf

Publications and source records attributed to P Nataf.

At least 19 recordsLinked to original sources
PubMed1999

Posttransplantation cytotoxic immunoglobulin G is associated with a high rate of acute allograft dysfunctions in heart transplant recipients.

BACKGROUND: The significance of anti-human leukocyte antigen immunoglobin G (IgG) detected in the posttransplantation course of heart graft recipients remains unclear. METHOD: Sera from 121 cardiac allograft recipients transplanted between January 1992 and December 1994 were screened for the presence of lymphocytotoxic antibodies in the first year after transplantation. Dithiothreitol was used to differentiate IgG from immunoglobulin M. RESULTS: Nineteen patients (15%) had cytotoxic IgG develop, mainly during the first month after transplantation. The percentage of women was higher in this group (42% vs 15.7%; P <.05). Donor to recipient mismatches for sex, blood typing, cytomegalovirus serology, and human leukocyte antigen typing were comparable between IgG producers and nonproducers. The frequency of acute allograft dysfunction during the first year after transplantation was significantly higher among patients producing IgG (42% vs 5.9; P <.001). Most of these acute allograft dysfunctions were independent of cellular rejection lesions but were associated with a thickening of the posterior wall and the interventricular septum during the acute episode. Finally, all the patients but one recovered. Recurrences were not uncommon and, at 1 year after transplantation, the dose of cyclosporine used in patients producing IgG was significantly greater, as was the left ventricular thickness. CONCLUSION: Posttransplantation cytotoxic IgG is not uncommon and appears to be associated with a high rate of acute allograft dysfunction. Development of these antibodies can be caused by a previous undetected immunization, as suggested by the higher percentage of women in the producer group. Correlation with histologic lesions of humoral rejection are discussed.

Adolescent↗
PubMed1999

Minimally invasive internal thoracic artery harvest: the hybrid approach.

BACKGROUND: Safe harvesting of the left internal thoracic artery is a difficult problem during minimally invasive coronary artery bypass grafting without cardiopulmonary bypass. A complete internal thoracic artery dissection through a limited approach is technically demanding and time consuming and different techniques have been proposed. METHODS AND RESULTS: Based on our experience, the different surgical approaches and technical considerations are reviewed. CONCLUSIONS: A hybrid technique using dissection under direct vision and completed by thoracoscopy is discussed and proposed as our preferred technique of internal thoracic artery harvesting.

Aged↗
PubMed1999

Video-assisted coronary artery bypass in patients with preexisting tracheostomy.

A new technique allowing revascularization of the left coronary artery through a small thoracotomy after videoscopic harvesting of both mammary arteries is proposed in patients with total laryngectomy. This anterior thoracotomy approach, of real interest in patients with a preexisting tracheostomy, needs to be compared with a classic sternotomy in terms of functional recovery and the prevention of mediastinal sepsis in certain high-risk categories of patients (e.g., obesity, diabetes) for bilateral mammary artery harvesting.

Aged↗
PubMed1998

Pacemaker infective endocarditis.

We identified 33 patients with definite pacemaker endocarditis--that is, with direct evidence of infective endocarditis, based on surgery or autopsy histologic findings of or bacteriologic findings (Gram stain or culture) of valvular vegetation or electrode-tip wire vegetation. Most of the patients (75%) were > or = 60 years of age (mean 66 +/- 3; range 21 to 86). Pouch hematoma or inflammation was common (58%), but other predisposing factors for endocarditis were rare. At the time that pacemaker endocarditis was found, the mean number of leads was 2.4 +/- 1.1 (range 1 to 7). The interval from the last procedure to diagnosis of endocarditis was 20 +/- 4 months (range 1 to 72). Endocarditis appeared after pacemaker implantation, early (< 3 months) in 10 patients and late (> or = 3 months) in 23 patients. Fever was the most common symptom, being isolated in 36%, associated with a poor general condition in 24%, and associated with septic shock in 9%. Transthoracic echocardiography showed vegetations in only 2 of 9 patients. Transesophageal echocardiography demonstrated the presence of lead vegetations (n = 20) or tricuspid vegetations (n = 3) in 23 of 24 patients (96%; p <0.0001 compared with transthoracic echocardiography). Pulmonary scintigraphy showed a typical pulmonary embolization in 7 of 17 patients (41%). Pathogens were mainly isolated from blood (82%) and lead (91%) cultures. The major pathogens causing pacemaker endocarditis were Staphylococcus epidermidis (n = 17) and S. aureus (n = 7). S. epidermidis was found more often in early than in late endocarditis (90% vs 50%; p = 0.05). All patients were treated with prolonged antibiotic regimens before and after electrode removal. Electrode removal was achieved by surgery (n = 29) or traction (n = 4). Associated procedures were performed in 9 patients. After the intensive care period, only 17 patients needed a new permanent pacemaker. Overall mortality was 24% after a mean follow-up period of 22 +/- 4 months (range 1 to 88). Eight patients who were significantly older (74 +/- 3 vs 63 +/- 3 years; p = 0.05) died < or = 2 months after electrode removal, whereas 25 were alive and asymptomatic.

Adult↗
PubMed1998

Facilitated vascular anastomoses: the one-shot device.

BACKGROUND: A mechanical system for facilitating vascular anastomosis (end-to-side, end-to-end) is described that enables the rapid construction of nonpenetrated, compliant junctions. The instrument (United States Surgical One-Shot system) simultaneously applies either 10 or 12 nonpenetrating, arcuate-legged titanium clips to everted vessel or prosthetic conduit edges. METHODS AND RESULTS: The instrument has been tested in animals (jugular and femoral vein jump grafts in carotid and femoral arteries, interpositional grafts, 20 pigs) and human cadaveric constructs (saphenous veins to left anterior descending coronary arteries, 20 cases, 5 brachiocephalic access fistulas) as end-to-side constructs. Clipped constructs have equivalent or superior physical properties to control sutured constructs (6-0 polypropylene) as gauged by burst and tensile strength. All studies were performed under Food and Drug Administration Good Laboratory Practice standards, and the device has been approved for marketing by the Food and Drug Administration. CONCLUSIONS: The device enables rapid and reproducible vascular anastomotic constructs with vessels as small as 1.8 mm outer diameter. The constructs are flanged, interrupted, and nonpenetrated.

Anastomosis, Surgical↗
PubMed1998

Minimally invasive coronary surgery: surgical considerations and assessment of cardiac troponin I.

OBJECTIVE: Minimally invasive coronary artery bypass grafting (MICABG) using internal thoracic artery (ITA) without median sternotomy and cardiopulmonary bypass (CPB) become a viable option for the management of proximal left anterior descending artery (LAD) disease. Recent studies have demonstrated that cardiac troponine I (cTnI), a new highly specific diagnostic marker of cardiomyocyte damage, is a reliable marker of cardiac ischemia during heart operations under CPB. METHODS: Between February 1996 and April 1997, 14 patients (10 males, 4 females aged 41-68) underwent MICABG with single-vessel bypass grafting for LAD stenosis (n = 9) or occlusion (n = 5). Video-assisted surgery with left anterior mini-thoracotomy was performed in ten patients and vertical parasternal thoracotomy in the other four. cTnI was measured before LAD occlusion (T0), during anastomosis (T1) and 10 min (T2), 6 h (T3), 24 h (T4), 48 h (T5), 72 h (T6) after coronary reperfusion. Assay methods used a specific enzyme-linked immunosorbent autoanalyzer (Stratus) in peripheral venous blood. Control coronary angiography was performed in all patients. RESULTS: There were no operative complications, no reoperations for bleeding. cTnI concentrations were expressed in ng/ml +/- SD. Mean cTnI level was <3.85+/-1 ng/ml (range 0-32.8). Values were: T0 = 0, T1 = 0.5+/-0.1, T2 = 1.15+/-0.2, T3 = 2.16+/-0.6, T4 = 1.5+/-0.3, T5 = 0.6+/-0.02, T6 = 0.4+/-0.01. Angiography showed patent grafts in 12 patients. A 'no flow situation' was demonstrated in a cardiac symptom-free patient, with reestablishment of flow on repeat angiogram at 6 months. In the other case, early ITA graft occlusion in a patient with two-vessel disease was correlated with a higher cTnI concentration (17.8 ng/ml). Percutaneous angioplasty was performed on the right coronary artery, complicated with dissection and cardiac failure. This patient died 3 months after the MICABG despite ventricular assist device. CONCLUSION: cTnI did not increase during and after coronary artery occlusion and local immobilization of the heart. It can be used to evaluate postoperative myocardial damage on the beating heart using MICABG.

Coronary Disease↗
PubMed1998

Safety of beating heart anastomosis during video-assisted coronary surgery attested by cardiac troponin I.

Our objective was to evaluate the safety of coronary anastomosis on the beating heart by measuring the release of cardiac troponin I during minimally invasive coronary artery bypass grafting (MICABG). Cardiac troponin I (cTnI) is a reliable marker of cardiac ischemia during heart operations under cardiopulmonary bypass (CPB). Ten patients (8 males and 2 females, aged 41-63) underwent MICABG with single vessel bypass grafting for left anterior descending coronary artery (LAD) stenosis (n = 7) or occlusion (n = 3). Video-assisted surgery with left anterior minithoracotomy was performed in all patients. Serial venous blood samples were collected for measurement of cTnI before LAD occlusion (T0), during anastomosis (T1) and 10 min (T2), 6 h (T3), 24 h (T4), 48 h (T5), and 72 h (T6) after coronary reperfusion. The assay method used a specific enzyme-linked immunosorbent Stratus autoanalyzer. Control coronary angiography was performed in all patients. There were no operative complications or reoperations for bleeding. The cTnI concentrations were expressed in ng/ml +/- SD. The mean cTnI level was less than 3.05 +/- 0.2 ng/ml (range 0-32.8). Values were T0 = 0, T1 = 0.4 +/- 0.03, T2 = 1.15 +/- 0.2, T3 = 2.16 +/- 0.6, T4 = 1.5 +/- 0.3, T5 = 0.6 +/- 0.02, and T6 = 0.4 +/- 0.01. Angiography showed patent grafts in 9 patients. In one case, early internal thoracic artery (ITA) graft occlusion in a patient with 2 vessel disease was correlated with a higher cTnI concentration (17.8 ng/ml). Percutaneous angioplasty was performed on the right coronary artery, complicated with dissection and cardiac failure. This patient died 3 months after the MICABG despite support from a ventricular assist device. In conclusion, collateral circulation developed in the setting of chronic coronary occlusion may be efficient for myocardial preservation during short periods such as coronary anastomosis. cTnI immunoassay confirmed the safety of coronary anastomosis on the beating heart during minimally invasive coronary operations.

Adult↗
PubMed1998

[The cardiowest total artificial heart: experience of 29 cases].

The authors studied the outcome of multi-organ failure in 29 patients with terminal cardiac failure and maintained with a Cardiotest total artificial heart whilst waiting for cardiac transplantation. Pre-implantation organ dysfunction was defined by the following criteria; assisted respiration of over 3 days, total billirubin and creatinine levels of over 2 mg/dL, a platelet count of less than 80,000/mL or a prothrombin ratio of less than 50% and central nervous system disturbances. Fourteen patients died during the period of circulatory assistance and 71% of deaths were due to multi-organ failure. Pre-implantation plasma total bilirubin levels were significantly higher in patients who died of multi-organ failure (p = 0.04). Eighty per cent of patients who died of multi-organ failure had at least 3 criteria of organ dysfunction before implantation of the artificial heart compared with only 37% in the other patients (p = 0.04). Finally, systemic vascular resistances before implantation were significantly lower in patients who died of multi-organ failure. The results of this study suggest that multi-organ failures does not develop during the period of circulatory assistance but represents an aggravation of a preexisting morbid condition. This observation should lead to a limitation of the indications of total circulatory assistance in some cases and, above all, to earlier intervention before multi-organ failure becomes irreversible.

Adult↗
PubMed1998

[Alcoholic cardiomyopathy and heart transplantation].

The recognition of alcoholic cardiomyopathy in patients with dilated cardiomyopathy is essential as they may regress, at least partially in a relatively short period, with abstention. The clinical history is the key to diagnosis because no other specific feature can identify the cause. Between January 1984 and July 1995, 26 candidates for cardiac transplantation with dilated cardiomyopathy and chronic alcoholism improved after withdrawal of alcohol. None of these patients was placed on the surgical waiting list. Patients with ischaemic cardiomyopathy, valvular disease or previous surgery for valvular hypertensive or congenital heart disease, documented viral myocarditis or connective tissue diseases, were excluded. The diagnostic criterion of chronic alcoholism was a total alcohol consumption of 292 kg and a duration of alcohol abuse of over 10 years. In addition to the clinical features, biological, electrocardiographic, echocardiographic and haemodynamic parameters were analysed. The mean age of the patients was 48 +/- 8 years. There were 25 men and 1 woman. The total mean alcohol consumption was 1,492 kg. The average follow-up period was 63 +/- 41 months. The interval between the onset of symptoms and abstention was 25 months. Haemodynamic improvement was observed in 25 cases. The average interval between alcoholic abstention and recovery was 11.7 months. One patient died suddenly. Improvement of symptoms, decrease of the cardiothoracic ratio and improvement of echocardiographic parameters were statistically significant. The increase in angiographic or isotopic ejection fraction and cardiac index and the decrease in mean pulmonary artery pressures were also statistically significant. These results confirmed the diagnosis of alcoholic cardiomyopathy. Therefore, patients with chronic alcohol abuse and dilated cardiomyopathy must be identified and treated for this problem and not placed on the waiting list for cardiac transplantation unless no improvement is observed after about 3 months of abstention.

Adult↗
PubMed1998

Recurrent left-sided heart leiomyosarcoma: should heart transplantation be legitimate?

Leiomyosarcoma of the heart is an uncommon primary malignant tumor with poor postoperative survival that may be measured in months. A leiomyosarcoma of the left atrium was diagnosed in a 47-year-old man. Initial admission was for acute pulmonary edema requiring emergency surgery. The tumor involved the left atrial cavity, and a radical resection was performed. Six months later an isolated myxomatous recurrence was detected. Heart transplantation was then performed. The patient is in good health 20 months after operation with no evidence of residual disease or recurrence. The literature has been reviewed. Surgical resection is not an adequate treatment for leiomyosarcoma of the left atrium and early heart transplantation probably offers the only hope for these patients.

Heart Atria↗
PubMed1997

Active native valve endocarditis: determinants of operative death and late mortality.

BACKGROUND: In this report, we reviewed 247 patients who underwent operation by our team for active native valve endocarditis between January 1979 and December 1993. METHODS: There were 201 male and 46 female patients (mean age, 45.4 +/- 6 years). The aortic valve was involved in 163 cases, the mitral valve in 36 cases, both mitral and aortic valves in 44 cases, and the tricuspid valve alone in 4 cases. The most common microorganisms were streptococci. Univariate Pearson (chi2 test) and multivariate (stepwise logistic regression [BMDPLR]) analyses were used to identify significant predictors of operative mortality, reoperation, and recurrent endocarditis. Cox proportional hazards regression model was used to study late survival. RESULTS: Operative mortality was 7.6% (n = 19). Increased age, cardiogenic shock at the time of operation, insidious illness, and greater thoracic ratio (>0.5) were the predominant risk factors; the length of antibiotic therapy appeared to have no influence. Two hundred thirteen patients were followed up. Median follow-up time was 6 years (range, 2 to 19 years). Overall survival rate (operative mortality excluded) was 71.3% +/- 3.8% at 9 years. Increased age, preoperative neurologic complications, cardiogenic shock at the time of operation, shorter duration of the illness, insidious illness before the operation, and mitral valve endocarditis were the predominant risk factors for late mortality. The probability of freedom from reoperation (operative mortality included) was 73.3% +/- 4.2% at 8 years; risk factors were younger age and aortic valve endocarditis. The rate of prosthetic valve endocarditis was 7%. No significant risk factor was found. CONCLUSIONS: Increased age, insidious illness, and hemodynamic failure are the main risk factors for operative mortality. Long-term survival is good except for patients with preoperative neurologic complications and mitral valve endocarditis.

Adult↗
PubMed1997

Nonpenetrating clips for coronary anastomosis.

BACKGROUND: A nonsuture clip technique (nonpenetrating titanium clips applied to everted tissue edges at high compressive forces) was used to perform coronary anastomoses in a clinical setting. METHODS: Clipped coronary anastomoses were performed in 10 patients. The anastomoses incorporated the left internal mammary artery to the left anterior descending artery (n = 1) and the saphenous vein to the right coronary artery (n = 5), the posterior descending artery (n = 2), the diagonal artery (n = 2), and one vein-to-vein proximal anastomosis (n = 1). RESULTS: The mean duration for completion of the anastomoses was 15 minutes (range, 7 to 20 minutes). This time was reduced from 20 minutes at the beginning of the clinical experience to 7 minutes for the last 3 patients. No technical complication was related to clip application and all patients had uneventful outcomes. Three anastomoses studied by coronary angiography were patent without stenosis. CONCLUSION: The clipped anastomotic technique has a rapid learning curve, the same safety as suture methods, and the potential for facilitating endoscopic vascular reconstructions.

Anastomosis, Surgical↗
PubMed1997

Thoracoscopic internal mammary artery harvesting: technical considerations.

BACKGROUND: Technical details of thoracoscopic harvesting of the internal mammary artery (IMA) are reported. This procedure allows a complete dissection of the left IMA from its origin at the subclavian artery to the sixth intercostal branches with transection of all collateral branches. METHODS: Between September 1995 and September 1996, thoracoscopic harvesting of the left IMA was performed on 32 patients who had undergone a minimally invasive coronary artery bypass grafting procedure. RESULTS: There were no conversions to a standard approach because of an injury to the graft and no reoperations for bleeding. The mean duration of the IMA harvesting procedure was 58.7 minutes (range, 20 to 130 minutes). CONCLUSIONS: This procedure enlarges the field of minimally invasive coronary artery bypass grafting techniques. The thoracoscopic harvest of the full length of the IMA allows the procedure to more closely replicate the open approach.

Endoscopy↗
PubMed1997

Endothelin-1 in the lungs of patients with pulmonary hypertension.

BACKGROUND: Pulmonary hypertension (PH) is characterized by an increase in vascular tone and an abnormal proliferation of muscle cells in the walls of pulmonary arteries. Recent studies have found high plasma endothelin-1 (ET-1) concentrations in patients with PH. This study was conducted to assess whether elevated circulating ET-1 levels in PH really reflect excessive local pulmonary production. METHODS: We prospectively studied ET-1 concentration in lung specimens from 6 control subjects and 13 patients with severe PH referred for lung or heart-lung transplantation (6 patients had primary PH and 7 PH secondary to congenital heart defect). Endothelin-like immunoreactivity (ET-LI) was measured in plasma and lung tissue, using a radioimmunoassay, after ET-1 extraction. Reverse-phase high-performance liquid chromatography was also performed. RESULTS: Peripheral venous plasma ET-LI concentrations in patients with PH, whatever the cause, were greater than those in controls (10.7 +/- 0.8 vs 5.3 +/- 0.7 pg/ml; P < 0.0005). Pulmonary ET-LI was significantly higher in patients with PH, irrespective of its cause, than in controls (25.2 +/- 5.1 vs 8.1 +/- 1.1 pg/mg, P < 0.03). ET-LI pulmonary concentrations were slightly higher in Eisenmenger than in primary PH, but this was not significant (27.1 +/- 8.6 vs 22.8 +/- 5.4 pg/mg). Linear regression analysis indicated a small but significant correlation between ET-LI pulmonary concentrations and pulmonary vascular resistance in the patients with PH (r = 0.38; P = 0.047). In each case, HPLC separation of ET indicated that most of the immuno-reactivity was detected in the same fraction as ET-1. CONCLUSIONS: The striking increase in ET-1 pulmonary concentration provides new evidence that excessive local pulmonary ET-1 production may contribute to the vascular abnormalities of pulmonary hypertension.

Adult↗
PubMed1997

Effect of the oxidation state of LDL on the modulation of arterial vasomotor response in vitro.

Although it is established that highly oxidized LDL modify both vasodilator and vasoconstrictor responses in normal and atherosclerotic arterial tissue, there is a paucity of data on the relationship between the degree of the oxidative modification of LDL and vasomotor response. We therefore compared the impact of native LDL (Nat-LDL), and of partially (P-oxLDL), of moderately (M-oxLDL) and of highly oxidized LDL (H-oxLDL) on the vasomotor response of isolated human internal mammary artery and of rat thoracic aorta. Copper-mediated oxidative modification for up to 24 h at 37 degrees C was characterised by a progressive increase in the net negative electrical charge of LDL, and in the content of oxysterols; by contrast, lipid hydroperoxide and TBARS content peaked in M-oxLDL at 6 h. Neither basal vascular tone nor vasoconstriction induced by KCl (100 mmol/l) were modified significantly in arterial segments in relation to the degree of LDL oxidation. While Nat-LDL did not modify the contractile response of rat aorta to norepinephrine, increase in the degree of oxidative modification of LDL progressively and significantly shifted the norepinephrine response curve to the right (EC50 values for Nat-LDL, M-oxLDL and H-oxLDL: 1.2+/-0.5x10(-8), 3.5+/-1x10(-7), 1.3+/-0.4x10(-6) mol/l respectively) with reduction in the maximal effect (74.5+/-12.2 and 100.1+/-6.2% for H-oxLDL and M-oxLDL respectively, P < 0.05 versus controls). Similar findings were made in human arteries treated with H-oxLDL (P < 0.05 for EC50 and maximal response versus controls). The acetylcholine-induced, endothelial-dependent relaxation of rat aortic segments was significantly and progressively impaired with increase in the degree of LDL oxidation, maximal relaxation with H-oxLDL being 3-fold less (P < 0.05) than Nat-LDL at the same protein concentration (100 microg/ml). Acetylated LDL was without effect. Our data indicate that the increase in the degree of copper-mediated, oxidative modification of LDL parallels progressive reduction in the vasomotor response of the arterial wall to norepinephrine-induced contraction and to acetylcholine-induced relaxation subsequent to precontraction. Our data are consistent with the hypothesis that the major oxysterols (7-ketocholesterol, 7beta-hydroxycholesterol) present in Ox-LDL underlie such effects.

Animals↗
PubMed1997

Video-assisted coronary bypass surgery: clinical results.

OBJECTIVE: Clinical experience with a video-assisted coronary artery bypass grafting procedure using the internal mammary artery is reported. The technique consists of a videoscopic harvesting of the left internal mammary artery (LIMA) to revascularise the left anterior descending artery (LAD) through a 4-cm left thoracotomy. METHODS: Between September 1995 and July 1996, we performed this procedure on 30 patients (29 males, 1 female; aged 38-71) with an isolated proximal LAD stenosis (n = 21) or occlusion (n = 9). All patients were symptomatic despite appropriate medication. A history of non-transmural myocardial infarction with myocardial viability was found in nine patients. Fourteen patients had a restenosis after previous percutaneous transluminal coronary angioplasty (PTCA). Mean left ventricular ejection fraction was 0.61 (< 0.3 in two patients). The LAD LIMA anastomosis was performed on the beating heart without cardiopulmonary bypass (CPB) in 26 patients. Femoral-femoral CPB was used in three patients because of unstable angina (n = 1) and intramyocardial LAD (n = 2). Conversion to sternotomy and standard CPB was necessary in one patient for extensive endarterectomy of the LAD. RESULTS: There were no operative complications and no reoperations for haemorrhage. Pulmonary infection was observed in one patient and wound infection in one patient. Patients who underwent the complete procedure on the beating heart without conversion or CPB were ready for discharge on the 5th postoperative day (36 h-13 days). Control coronary angiography was performed in 20 patients. In all cases, the graft was patent. In 17 cases, there was a patent graft with no evidence of anastomotic stenosis. An occlusion of the distal segment of the LAD with a retrograde perfusion of the proximal segment and septal branches by the LIMA was found in one case. This patient was symptom-free and the stress test was negative. An anastomotic stenosis was noted in two patients and was treated by angioplasty (n = 1) or conventional surgery (n = 1). CONCLUSION: In conclusion, the efficiency of this minimally invasive approach should be prospectively compared with similar revascularisation with PTCA or surgical approaches using sternotomy with or without CPB.

Angioplasty, Balloon, Coronary↗