[Endovascular ultrasonography. A technology with a promising future].
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Blood Vessels↗
Biomedical subjects
M Bertrand
Publications and source records attributed to M Bertrand.
Effects of thoracic extradural block on diaphragmatic electrical activity and contractility after upper abdominal surgery.
BACKGROUND: Upper abdominal surgery (UAS) induces diaphragmatic dysfunction. Thoracic extradural block (TEB) using 0.5% bupivacaine improves some pressure and motion indices of diaphragmatic function. However, no direct information on diaphragmatic activity is available after UAS. The aim of this study was to assess diaphragmatic electrical activity (Edi) after UAS before and after TEB. METHODS: A postoperative electromyogram was obtained, using intramuscular electrodes inserted by the surgeon in the costal and crural parts of the diaphragm, in 14 patients undergoing abdominal aortic surgery. Tidal changes in abdominal (VAB) and rib-cage (VRC) volumes, and gastric (delta Pgas), esophageal (delta Pes), and transdiaphragmatic (delta Pdi) pressures were used to measure tidal volume (VT) and respiratory rate and to provide indirect indices of diaphragmatic activity from the two ratios VAB/VT and delta Pgas/delta Pdi. These respiratory variables were obtained preoperatively. Postoperatively, measurements including Edi were obtained before and after a segmental epidural block, reaching a T4 level was achieved with 0.5% plain bupivacaine. RESULTS: Upper abdominal surgery induced an increase in respiratory rate (+28 +/- 15%; P < .01), associated with a decrease in VAB/VT (from 0.75 +/- 0.11 to 0.07 +/- 0.08; P < .01), delta Pgas/delta Pdi (from 0.3 +/- 0.08 to 0.01 +/- 0.19; P < .05), and VT (-30 +/- 14%; P < .01). After surgery, all patients exhibited electrical diaphragmatic activity that increased with TEB by 48 +/- 28% (P < .01) and 60 +/- 22% (P < .001) for the cural and costal segments, respectively. The ratio delta Pdi/Edi, used to evaluate diaphragmatic contractility, was not modified by TEB. Tidal volume, respiratory rate, and delta Pgas/delta Pdi returned to preoperative levels, whereas VAB/VT increased but remained different from preoperative values. CONCLUSIONS: This study demonstrates that TEB produces an increase in diaphragmatic activity, identical for the two segments of the muscle. Interruption of afferents that produce an inhibitory effect on diaphragmatic activity appears the most attractive hypothesis to explain the consequences of TEB after UAS.
Aorta, Abdominal↗
[Time and narrative: the psychic character of history].
The thesis developed here is that of the "psychic character of history", following Simmel's terminology. Psychic character must not, however, be understood as a lack of objectivity. On the contrary, it is an instrument of investigation, which indicates the conditions of objectification in the human and social sciences. If the historian always reconstructs a past time, it is because the past form is the mode, specific to history, of distancing/objectification. Anthropology and sociology make use of other modes of distancing. The reconstruction that takes place during psychoanalysis is thus, on three points of comparison, clarified by the narrative process proper to history.
History↗
[Hemangiopericytoma: a case report].
We describe one case of hemangiopericytoma touching a 44-year-old man. It is a rare vascular tumor originating from pericytes surrounding capillaries. The main typical features of it are the difficulty in doing an histologic diagnosis and the impossibility to make out a reliable prognosis. The therapy of choice is a surgical procedure sometimes in combination with radio- and/or chemotherapy.
Adult↗
[Angiography of the left ventricle].
Left ventricular angiography in the 30 degree right anterior oblique projection is the reference method of calculating volumes and assessing segmental wall motion. The calculation of volumes is based on the surface-length or Simpson's methods which assume that the ventricle has an ellipsoid shape. The use of both the right and left anterior oblique projections only slightly improves the accuracy of the method and is not necessary in routine procedures. The global parameters of left ventricular function are the end-systolic and end-diastolic volumes and the ejection fraction. Segmental wall motion assessment provides a more precise analysis of left ventricular function. Many methods have been described but only two have been validated clinically: the Stanford method proposed by Ingels in which fractional shortening is calculated with respect to a point situated at 69% of the length of the axis between the apex and the anterior aortic border, and the more complex Rotterdam method reported by Slager. The introduction of digitisation of the image has enabled calculation of these different parameters in routine investigations.
Angiography↗
Wiktor stent implantation in patients with restenosis following balloon angioplasty of a native coronary artery.
Intracoronary stenting has been introduced as an adjunct to balloon angioplasty aimed at overcoming its limitations, namely acute vessel closure and late restenosis. This study reports the first experience with the Wiktor stent implanted in the first 50 consecutive patients. All patients had restenosis of a native coronary artery lesion after prior balloon angioplasty. The target coronary artery was the left anterior descending artery in 26 patients, the circumflex artery in 7 patients and the right coronary artery in 17 patients. The implantation success rate was 98% (49 of 50 patients). There were no procedural deaths. Acute or subacute thrombotic stent occlusion occurred in 5 patients (10%). All 5 patients sustained a nonfatal acute myocardial infarction. Four of these patients underwent recanalization by means of balloon angioplasty; the remaining patient was referred for bypass surgery. A major bleeding complication occurred in 11 patients (22%): groin bleeding necessitating blood transfusion in 6, gastrointestinal bleeding in 3 and hematuria in 2. Repeat angiography was performed at a mean of 5.6 +/- 1.1 months in all but 1 patient undergoing implantation. Restenosis, defined by a reduction of greater than or equal to 0.72 mm in the minimal luminal diameter or a change in diameter stenosis from less than to greater than or equal to 50%, occurred in 20 (45%) and 13 (29%) patients, respectively. In this first experience, the easiness and high technical success rate of Wiktor stent implantation are overshadowed by a high incidence of subacute stent occlusion and bleeding complications.(ABSTRACT TRUNCATED AT 250 WORDS)
Angioplasty, Balloon, Coronary↗
The relation between triglyceride synthesis in peripheral tissues and postprandial plasma triglyceride levels: preliminary evidence of a role for acylation stimulating protein.
The present study examines the hypothesis that the rate at which peripheral tissues synthesize triglycerides is a key determinant of the rate at which they are removed from plasma. The cells of greatest interest in this regard would, of course, be the adipocytes. However, serial sampling of this tissue is not possible in man. We have approached the question indirectly, by studying triglyceride synthesis in human mononuclear cells before and after an oral fat load. In addition, plasma levels of Acylation Stimulating Protein (ASP) were measured after an overnight fast and 4 h after ingestion of the oral fat load. Similar measurements were made in the same subjects after fasting overnight and with the fast extended for 4 additional hours. With the extended fast, no parameter measured changed significantly. However, after the oral fat load, the following changes were found to be significant: plasma triglycerides increased (63.6 +/- 31.1 vs 101.5 +/- 43 mg/dl, p less than 0.005) as did d less than 1.006 g/ml triglycerides (42.3 +/- 22.8 vs 78.0 +/- 39.7 mg/dl, p less than 0.005) and plasma ASP (10.4 +/- 2.2 vs 14.7 +/- 2.3 mg/dl, p less than 0.005). In addition, the rate of triglyceride synthesis in the mononuclear cells increased significantly (1.22 +/- 0.3 vs 1.52 +/- 0.3 nmol oleate/mg cell protein per h, p less than 0.005). There was also a significant inverse relation between the increase in the d less than 1.006 triglycerides between 0 and 4 h and the increase in triglyceride synthesis in the mononuclear cells (r = 0.91, p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)
Acylation↗
Morphologic change in coronary artery stenosis with the Medtronic Wiktor stent: initial results from the core laboratory for quantitative angiography.
The purpose of this study was to assess the early changes in stenosis geometry after implantation of the Medtronic Wiktor stent in human coronary arteries. Morphologic changes were evaluated by quantitative coronary angiography using automated edge detection. The hemodynamic significance of the morphologic changes were assessed by the calculation of the theoretical pressure drop across the dilated and stented stenosis derived from the Poiseuile and turbulent resistances assuming a coronary blood flow of either 0.5, 1, or 3 ml/sec. Fifty patients were studied before and immediately after stent implantation. The stented coronary artery was the left anterior descending artery in 26 patients, the circumflex artery in eight patients, and the right coronary artery in 16 patients. Stent implantation resulted in an additional increase in the minimal luminal cross-sectional area and minimal luminal diameter of the dilated vessel without changing the curvature of the stenosis. Furthermore, there was a significant reduction of the "plaque area." This was associated with a normalization of the calculated resistances to flow and pressure drop across the stenosis. To a minimal extent, recoil (0.1 +/- 0.36 mm) was observed after stent implantation.
Adult↗
A new radioimmunoassay for the determination of the angiotensin-converting enzyme inhibitor perindopril and its active metabolite in plasma and urine: advantages of a lysine derivative as immunogen to improve the assay specificity.
A new radioimmunoassay (RIA) was developed for the direct measurement of perindoprilate (PT), the active metabolite (diacid) of Perindopril (P), an angiotensin-converting enzyme (ACE) inhibitor. Antibodies were raised in rabbits against the lysine derivative of PT conjugated to bovine serum albumin. The p-hydroxyphenyl derivative of the lysine analogue was used for preparation of the radioligand by iodination (125I). Cross-reactivities for the glucuronide metabolites of P and PT are low (0.25 and 3.5%, respectively). The theoretical limit of detection is 0.2 nM, the sensitivity attainable with random samples is about 0.5 nM. Within- and between-assay variabilities observed were 4.2-6.7 and 2.8-5.9%, respectively (concentration range 2.1-41.7 nM). Serial dilution of plasma and urine samples showed excellent parallelism (r greater than 0.95; P less than 0.001). Recoveries of PT spiked to urine and plasma samples were 90-120%. The prodrug P can be measured in the same sample (plasma/urine) after chromatographic separation on a Dowex AG 1 x 2 anion-exchange column and quantitative alkaline hydrolysis of the P-containing fraction. It is concluded that the specificity and sensitivity of this assay are amply sufficient for pharmacokinetic studies and in patient monitoring.
Angiotensin-Converting Enzyme Inhibitors↗
Combined epidural and general anesthesia versus general anesthesia for abdominal aortic surgery.
The goal of this randomized study of high-risk surgical patients was to determine whether intraoperative thoracic epidural anesthesia in combination with light general anesthesia alters postoperative morbidity when compared to a standard technique of "balanced" general anesthesia. A total of 173 patients scheduled for abdominal aortic reconstruction were admitted to the study; 86 were to receive "balanced" general anesthesia (group 1) and 87 thoracic epidural anesthesia in combination with light general anesthesia (group 2). Preoperative evaluation included standard clinical tools, dipyridamole thallium gammatomography, and radionuclide angiography. In these patients, all of whom had peripheral artery disease, there were no significant differences in associated coronary artery disease, hypertension, and cardiovascular treatment. The distribution of left ventricular ejection fraction and the number of patients with thallium redistribution were not statistically different between the two groups. During the postoperative period, group 1 received analgesia of subcutaneous morphine (n = 35), epidural fentanyl (n = 30), or epidural bupivacaine (n = 21). In group 2, 6 patients with a nonfunctioning epidural catheter due to technical failure received a balanced general anesthesia and were eliminated from the study. During the postoperative period, group 2 received analgesia of subcutaneous morphine (n = 26), epidural fentanyl (n = 25), or epidural bupivacaine (n = 30). Cardiovascular morbidity did not differ between the two groups: 22 patients in group 1 and 19 patients in group 2 had a major postoperative cardiac event.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
An experimental study in electrical impedance tomography using backprojection reconstruction.
This paper reports on experiments designed to evaluate the performance of the equipotentials backprojection method under conditions modeling those of proposed applications of electrical impedance tomography. Small spherical targets were placed inside a saline-filled tank with dimensions similar to a human torso. Data were acquired with a computer-based instrument that applies current to pairs of electrodes located on two horizontal planes and records potential differences between electrodes of a third plane. The relative contrast produced by nonconducting spheres in a uniform saline background was measured on the reconstructed images and used to determine system sensitivity to target volume and to the radial and vertical positions of single spheres. Results show that for radial positions within a critical radius sensitivity is always maximum when the spheres center is on the recording plane and decreases gradually when the target is moved outside this plane. Localization of simple targets in 3-D, with data acquired from multiple recording planes, appears feasible. The results provide guidelines for the interpretation of images with complex 3-D conductivity distributions.
Electric Conductivity↗
Relation of arteriographically defined coronary artery disease to serum lipoprotein particles mapped with monoclonal antibodies.
BACKGROUND: This study was designed to investigate the relation of a molecular analysis of apolipoprotein B (apoB)-containing atherogenic lipoprotein particles to coronary artery disease (CAD) in middle-aged men. METHODS AND RESULTS: Two groups of men were studied. The first consisted of 97 patients with angiographically documented CAD (greater than 50% stenosis of at least one coronary artery). The second group consisted of 145 subjects without symptomatic CAD, who served as controls. In both groups, measurements were obtained for total cholesterol level, triglyceride level, cholesterol contents in apoB- and nonapoB-containing particles (LpB, LpnonB), total apoB and apolipoprotein AI (apoAI levels), lipoprotein particles recognized by monoclonal antibodies anti-apoB (LpBL3, LpBL5, LpBL7) and anti-apoAI (LpAI-2GII). Taking into account age, body mass index, hypertension, diabetes, smoking habits, and drug consumption, the analysis showed that the mean levels of cholesterol were identical in both groups but differed when cholesterol content in LpB and LpnonB subfractions were assessed, thus reflecting an increase in the low density fraction and a decrease in the high density fraction, respectively. This was confirmed by an increase in total apoB and a decrease in total apoAI. Measurements of LpBL3, LpBL5, LpBL7, and LpAI-2GII particles also discriminated between the two groups. After adjustment for cholesterol content in LpnonB particles, a difference in total apoB was no longer significant between groups, whereas LpBL3, LpBL5, and LpBL7 levels remained significantly higher in CAD patients. CONCLUSIONS: The measurement of separate concentrations of apoB in different particles may permit a more-accurate assessment of CAD risk than measurements of total apoB levels.
Adult↗
[Torsades de pointes and prolongation of the duration of QT interval after injection of droperidol].
Following a case of torsades de pointe (TDP) after the injection of droperidol (D), the authors studied the electrocardiographic variations caused by the drug. Fifty five unselected patients under the same conditions (general anesthesia) were given D (0.25 mg/kg IV). Significant prolongation of the QT interval was seen in 70% of cases by the end of the first minute. QT interval and the ratio of QTm (measured) over QTt increased from 387 +/- 34 ms to 423 +/- 37 ms (p less than 0.0001) and from 1.06 +/- 0.08 to 1.28 +/- 0.1 (p less than 0.001) respectively. These changes could favourise the onset of TDP. Although exceptional in terms of the extensive use of the neuroleptic in question, this possibility indicates the need for monitoring of the duration of QT before and during treatment with droperidol and for prescription of the drug to be avoided in circumstances known to be propitious to this arrhythmia (bradycardia, hypokalemia, anti-arrhythmic drugs).
Adult↗
[Guidelines for the training of practitioners in coronary angiography and angioplasty, the organization and equipment of centres of coronary angiography and transluminal angioplasty].
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Angioplasty, Balloon, Coronary↗
Health concerns of female patients: politics or apathy?
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Female↗
[Vasomotor activity and coronary insufficiency].
Provocative testing has provided a method of evaluating the important role of vasomotor tone in coronary artery disease. The most sensitive test is the ergonovine (Methergin) test. This is a specific and reliable method of defining the clinical situations in which coronary spasm is common: --focal coronary artery spasm is mainly observed in resting angina alone or in association with effort angina. The prognosis of spasm is excellent with calcium antagonist therapy provided there is no other associated pathology such as left ventricular failure or triple vessel disease; --in the six weeks following myocardial infarction, focal coronary artery spasm is a common event: 20% of coronary angiographies. After six weeks, spasm is much less frequent. It does not influence the prognosis. This type of spasm is probably related to the scarring process; --coronary artery spasm is frequently associated with restenosis after coronary angioplasty, a process which is histologically related to proliferation of smooth muscle; --diffuse increase in coronary vasomotor tone is a much rarer pathology, perhaps related to global changes in vascular tone as its association with the Raynaud syndrome and with migraine would suggest. It presents clinically with resting angina and sometimes by typical Prinzmetal angina; --finally, vosomotor tone plays an important role in the daily life of coronary patients. Holter recordings for the detection of silent myocardial ischemia have shown episodes of myocardial ischemia at lower myocardial oxygen consumption levels than those usually recorded during exercise stress testing, which suggests a reduction in oxygen supply, that is to say coronary vasoconstriction. Changes in coronary vasomotor tone can modify the diameter of healthy coronary arteries by 100%.(ABSTRACT TRUNCATED AT 250 WORDS)
Coronary Disease↗
Comparison of isoflurane with sodium nitroprusside for controlling hypertension during thoracic aortic cross-clamping.
The aims of this randomized study were (1) to determine if isoflurane is effective in controlling blood pressure during thoracic aortic cross-clamping, and (2) to compare its effects on hemodynamics and oxygen transport to those of sodium nitroprusside. Sodium nitroprusside (SNP group, n = 10) or isoflurane (ISO group, n = 10) was started 2 minutes before cross-clamping and was adjusted to maintain systolic arterial pressure as near as possible to preinduction values. The duration of thoracic aortic cross-clamping was 26 +/- 4 minutes in the SNP group and 30 +/- 4 minutes in the ISO group. Administration of isoflurance and sodium nitroprusside was stopped 2 minutes before unclamping. The same anesthetic technique using fentanyl, 6 micrograms/kg, flunitrazepam, 0.02 mg/kg, pancuronium, 0.1 mg/kg, and 50% N2O was used for all patients. At the time of clamping, either isoflurance (maximal expired concentration, 2.5% +/- 0.3%) or sodium nitroprusside (cumulative dose, 11.1 +/- 1.0 mg) was effective in maintaining the systolic blood pressure below 160 mm Hg, whereas the pulmonary capillary wedge pressure did not change. However, only SNP was able to bring the arterial pressure above the cross-clamp back to postinduction levels. During clamping, stroke index values were similar in both groups, but cardiac index increased only in patients receiving SNP. In both groups, at clamping and unclamping, PvO2 was higher than postinduction values, indicating that throughout the study the oxygen needs of the perfused area were adequately met. There was no evidence of acute left ventricular decompensation because pulmonary capillary wedge pressures did not abruptly increase, nor did pulmonary edema occur.(ABSTRACT TRUNCATED AT 250 WORDS)
Aorta, Abdominal↗
[Venous catheterization and congenital abnormalities of the superior vena cava].
Persistent left superior vena cava is encountered in about 0.3 to 0.4% of human beings. It derives from remnants of the left cardinal vein system. This results in either a duplication of the superior vena cava or in a single left vena cava. The diagnosis is easy in case of associated cardiovascular anomalies. Two cases of single left vena cava and one case of duplication of the superior vena cava are described. All were identified owing to repeatedly aberrant courses of central venous catheters. Diagnosis was easily provided by angiography. Clinical course was uneventful. Despite its usual good tolerance, the persistence of a left vena cava, as an isolated anomaly, must not be neglected as it carries many practical implications which are reviewed.
Adult↗