[Atrial fibrillation: from cardiology to perioperative management]. / Fibrillation atriale en anesthésie-réanimation : de la cardiologie médicale à la période périopératoire.

Atrial fibrillation (AF) is the most frequent arythmia. During the perioperative period and in intensive care units, management of patients with AF is frequent and difficult. As in cardiology, two main issues are present: the risk of acute hemodynamically instability and the risk of thromboembolic complication. Cardiological guidelines recently published must guide the management of patients in this context. Two main factors must be kept in mind: acute AF in these situations are often of short duration; the risk of anticoagulation can be superior to the risk of thrombotic complication in this situation. An individualized benefit-risk analysis must be done in each patient. New treatments, antiarrhythmic or mainly antithrombotic drugs, are under evaluation and will be soon available.

[Dosimetry with radiosensitive gels in radiotherapy. Methods]. / Dosimétrie par gels radiosensibles en radiothérapie. Intérêt et méthodes.

The goal of conformal radiotherapy is to concentrate the dose in a well-defined volume by avoiding the neighbouring healthy structures. This technique requires powerful treatment planning software and a rigorous control of estimated dosimetry. The usual dosimetric tools are not adapted to visualize and validate complex 3D treatment. Dosimetry by radiosensitive gel permits visualization and measurement of the three-dimensional dose distribution. The objective of this work is to report on current work in this field and, based on our results and our experience, to draw prospects for an optimal use of this technique. Further developments will relate to the realization of new radiosensitive gels satisfying, as well as possible, cost requirements, easy realization and use, magnetic resonance imagery (MRI) sensitivity, tissue equivalence, and stability. Other developments focus on scanning methods, especially in MRI to measure T1 and T2.

[Recognizing interventional biology as a specialty on its own]. / Pour une reconnaissance de la Biologie Interventionnelle. Rapport au nom d'un groupe de travail bi-académique (Académie nationale de Médecine--Académie nationale de Pharmacie).

Changing therapeutic strategies have led to the development of new techniques where elements of the human body, including cells, tissues or even organs, are removed from the body in order to modify their potential before reintroducing them into the body. The ex vivo manipulations are performed by biologists working in close coordination with clinicians who determine the indications and perform the procurement and reintroduction steps. We propose the term interventional biology for this type of activity and suggest that, beyond the various domains considered including reproduction biology, and cell and gene therapy, it should be recognized as a specific form of practice of medical biology. Recognized as a specialty on its own, this type of activity could be better organized helping improve training, rules of good practice, performance assessment, and establishment of individual responsibilities. This would provide the means for guaranteeing efficacy and safety for a rapidly growing field of activity.

In vivo comparison between computed tomography and magnetic resonance image analysis of the distal radius in the assessment of osteoporosis.

In a prospective case-control cross-sectional study, we investigated the usefulness of both computed tomography (CT) and magnetic resonance (MR) image analysis of the distal radius for distinguishing a small sample of fractured osteoporotic women from control women regardless of bone mineral density. The study population included 12 subjects who were divided into two groups according to their bone status. The first group consisted of six women with at least one vertebral fracture occurring in the absence of high-energy trauma, and the second group consisted of six women without disease affecting bone mass or bone metabolism. Cross-sectional and coronal slices were obtained from both CT and MR systems. For CT images, the slice thickness was 1000 jim and the plane resolution was approx 200 jim x 200 jim. MR images were obtained from a 1.5-T imager with a two-dimensional spin-echo Ti-weighted sequence leading to a slice thickness of 2000 jim and a plane resolution of 195 jim x 195 jim. Bone texture analysis was performed using fractal and structural methods leading to the measurement of 23 features. Most of the structural variables derived from histomorphometric parameters and were measured after segmentation from a binary or a skeletonized image. Bone densitometry was measured by dual-energy X-ray absorptiometry both at the lumbar spine and the nondominant femoral neck. On cross-sectional slices, 12 variables, mainly obtained from structural analysis, were significantly different between the two groups for CT images (p < 0.05) against two variables only for MR images (p < 0.05). The number of variables statistically different between the two groups was significantly higher for CT images compared with MR images (p = 0.003). In the same way, odds ratios for fracture per 1 control group standard deviation decrease were significant for 10 variables on CT images, whereas, in contrast, none of the variables measured on MRI images led to significant odds ratios. The results obtained for the two methods on coronal slices were poorer without a difference between either CT or MR images in terms of discrimination between fracture and nonfracture subjects. In conclusion, this study suggests that bone texture analysis obtained from CT compared with MRI offers a best discrimination between controls and osteoporotic patients, probably the result to the spatial resolution. which is better for CT than for MR images.

Image analysis of the distal radius trabecular network using computed tomography.

Bone texture analysis might provide information about bone structure in a noninvasive manner. In a prospective case-control cross-sectional study we investigated the value of computed tomography (CT) image analysis of the distal radius in the assessment of osteoporosis. Twenty patients suffering from postmenopausal osteoporosis were studied and compared with 21 age-matched controls. Eight slices were selected in each patient: four consecutive coronal slices and four consecutive cross-sectional slices. Bone texture analysis was performed using statistical, fractal and structural methods leading to the measurement of 32 features. Structural variables derived from histomorphometric parameters were measured after segmentation from a binary or a skeletonized image. Bone mineral density was measured by dual-energy X-ray absorptiometry both at the lumbar spine and the femoral neck. Eight of the 9 statistical features were significantly different in osteoporotic women as compared with controls (coronal slices, p < 0. 05). Seven structural variables were statistically different between the two groups on coronal slices (p < 0.05): valley surface area, bone volume/tissue volume, trabecular partition, Euler's number, trabecular bone pattern factor, node-to-node strut count and terminus-to-terminus strut count. The most significant results on coronal slices (p < 0.01) concerned 4 structural features: trabecular partition, Euler's number, trabecular bone pattern factor and terminus-to-terminus strut count. Three features were statistically different (p < 0.01) between the two groups on cross-sectional slices (skeletonization from gray levels). A few features yielded by texture analysis were correlated with both lumbar spine and femoral neck bone mineral density, but the level of these correlations was weak (r < 0.5). In conclusion, CT image analysis of the distal radius is a useful tool for characterizing bone texture alterations in osteoporotic women. These findings are in keeping with microarchitectural osteoporosis-related changes diagnosed on bone biopsies.

Automatic quality assessment protocol for MRI equipment.

The authors have developed a protocol and software for the quality assessment of MRI equipment with a commercial test object. Automatic image analysis consists of detecting surfaces and objects, defining regions of interest, acquiring reference point coordinates and establishing gray level profiles. Signal-to-noise ratio, image uniformity, geometrical distortion, slice thickness, slice profile, and spatial resolution are checked. The results are periodically analyzed to evaluate possible drifts with time. The measurements are performed weekly on three MRI scanners made by the Siemens Company (VISION 1.5T, EXPERT 1.0T, and OPEN 0.2T). The results obtained for the three scanners over approximately 3.5 years are presented, analyzed, and compared.

CT scan texture analysis of the distal radius: influence of age and menopausal status.

OBJECTIVES: To gain information on bone architecture by performing bone texture analysis in a sample of women covering a broad age range. PATIENTS AND METHODS: We studied 29 healthy women aged 23 to 80 years (55 +/- 18 years), 19 of whom were postmenopausal. None was taking drugs known to influence bone mass or bone metabolism. Computed tomography of the nondominant distal radius was performed with 1 mm slice thickness and 1 mm gap. Four consecutive coronal and four consecutive axial sections were selected for each patient and entered into a PC-type computer. Bone texture was evaluated using grey level run length analysis (five parameters), differential local variation analysis (four parameters), fractal analysis (two parameters), trabecular network extraction and three-dimensional relief characterization. The mean of each study parameter for the four coronal sections and for the four axial sections was calculated. Absorptiometry was done in 16 patients. RESULTS: Linear correlations with age were strongest (P < 0.001) for parameters measured on coronal sections by trabecular network extraction, i.e., trabecular bone volume (r = -0.68), trabecular plate separation (r = -0.65), total skeletal length (r = -0.71), number of nodes (r = 0.73), number of node-node segments (r = -0.74) and trabecular bone pattern factor (r = 0.71). Also, these parameters were significantly different between premenopausal women (33 +/- 9 years) and postmenopausal women (67.3 +/- 9 years). Correlations between bone mineral density and texture parameters were few in number and modest in strength, suggesting that the parameters measured may reflect bone structure rather than bone mass. CONCLUSION: Bone texture in women undergoes changes with advancing age that may reflect alterations in bone microarchitecture.

Coronary artery revascularisation without extracorporeal circulation. Indications and results.

OBJECTIVE: Coronary artery revascularisation without extracorporeal circulation is a technique which can be performed in selected patients in need of a coronary artery bypass graft. METHODS: Consecutive patients (210) underwent coronary artery bypass graft without extracorporeal circulation. Indications were high risk patients, or single coronary artery lesion. To predict perioperative mortality, preoperative risk factors were reviewed, and Parsonnet score was calculated. RESULTS: There were seven deaths (3.3%), and univariate analysis revealed greater age, NYHA, and poor ejection fraction to be the only predictors of early mortality. Perioperative myocardial infarction included 15 patients (7.1%), most of them seen in the multiple bypass group (10/39, 26%). Patients were divided into low risk (Parsonnet score < 15) 155 patients with two deaths (1.2%), and high risk (Parsonnet score > 15) 55 patients with five deaths (9%). Complete revascularisation was performed in the low risk group, while in the high risk only the symptomatic vessel was bypassed and other angiographic lesions treated with postoperative angioplasty (10 patients). A total of 12 patients developed early postoperative angina (5.7%), 9 presented an anastomosis dysfunction which was treated by angioplasty (5) and surgery (4), and 188 patients (85.7%) did not receive transfusions while 190 patients (90.4%) did not need postoperative inotropes. Length of stay, operating room time, and medical costs were all significantly reduced. CONCLUSIONS: Myocardial revascularisation without extracorporeal circulation can be performed with a low operative mortality, and minimal morbidity only in patients undergoing single bypass revascularisation. It can also be performed as part of a multiple revascularisation strategy in association with angioplasty in high risks patients.

Lung resection for recurrence after pneumonectomy for metastases.

Resection of pulmonary recurrences after pneumonectomy for metastases is exceptional. Nevertheless in carefully selected patients surgery on the residual lung might be successfully performed. From January 1987 to February 1996, 5 patients underwent metastasectomy on single lung after pneumonectomy performed for the same metastatic disease. There were 3 male and 2 female with a mean age of 38 years at the time of surgery on single lung. All patients had a FEV1 > 40%. One patient (n degree 1) had 2 consecutive operations (wedge resections) on the right lower lobe followed 17 months later by right inferior lobectomy for metastases of soft tissue sarcoma. Three patients had only an operation on the residual lung (patient n degree 2 had 2 wedge resections for carcinoma; patient n degree 3 had 7 wedge resections for carcinoma; patient n degree 4 had 6 wedge resections for osteogenic sarcoma). The last patient (n degree 5) had 2 wedge resections on the right upper lobe and a large wedge resection on the right lower lobe for metastases of malignant corticosurrenaloma using a cardiopulmonary femoro-femoral by-pass without cardiac arrest. She postoperatively developed a right lower lobe venous infarction treated subsequently with a completion right lower lobectomy. She died in the postoperative course from cardiorespiratory insufficiency. The other patients had an uneventful postoperative course. Two patients (n degree 2 and n degree 4) died of their disease 14 and 12 months respectively after the surgery on the residual lung; by contrast 2 patients (40%) (n degree 1 and n degree 3) are still alive without recurrences 36 and 27 months after the last resection. In selected patients aggressive surgery for metastases on the residual lung can be successfully performed but the benefits in terms of long-term disease-free survival remain to be determined.

A new video-assisted thoracoscopic surgical technique for interruption of patient ductus arteriosus in infants and children.

Classic surgical interruption of patent ductus arteriosus was partially replaced by transcatheter endovascular closure in 1971. We describe a new technique for ductus closure by video-assisted thoracoscopic surgical interruption, derived from video-assisted endoscopic surgery. With the patient under general anesthesia and intubated, two 5 mm holes were made through the left thoracic wall. A video camera and specially devised surgical tools were introduced; such as scissors, dissectors, and clip appliers. The ductus was dissected, and two titanium clips were applied, completely interrupting the ductus. Thirty-eight patients were operated on from April 1991 to April 1992. Mean age was 23.3 months (range 1.5 to 90 months) and mean weight was 9.5 kg (range 2.4 to 25 kg). Six had associated lesions not necessitating immediate surgical treatment. All had successful closure of the patent ductus with the video-assisted technique, but two needed two such procedures, one because of incomplete immediate ductus closure and one because of partial opening of the clip after 24 hours. One patient had recurrent laryngeal nerve injury and four had pneumothorax on the left side. The usual hospital stay was 2 or 3 days. There were no other complications and no deaths. Video-assisted thoracoscopic surgical interruption was a rapid, safe, and successful technique for closure of the patent ductus arteriosus. Better dissection of the ductus decreased the risk of recurrent laryngeal nerve injury and that of clip opening. In the last 26 patients, in whom a 2 mm multiperforated catheter was used for chest drainage during the first hours, no pneumothoraces occurred. Video-assisted thoracoscopic interruption of the patent ductus arteriosus is feasible in low-weight infants, whereas transcatheter endovascular closure of the ductus usually is not possible. The technique will be applied to premature infants with new instruments designed for the size of these patients.

Mediastinal infection after cardiac operation. A simple closed technique.

From March 1984 to March 1987, a simple closed method, previously described for the treatment of osteomyelitis after orthopedic operations, was used to treat deep sternal infection in 11 patients. The basis of this technique is, after meticulous débridement of the wound, to drain all the infected areas with small catheters connected to a bottle inside of which a strong (700 mm Hg) negative pressure is created (Redon drainage device). The method does not require irrigation. The maximum duration of the drainage was 24 days and complete recovery was obtained in all patients without further surgical treatments. The comfort of the patients was optimal.

[Postoperative inotropic treatment in cardiac surgery of the newborn infant and infant]. / Traitement inotrope postopératoire dans la chirurgie cardiaque du nouveau-né et du nourrisson.

Corrective cardiac surgery in infants and neonates induces acute circulatory and anatomical changes which, together with the myocardial ischaemia of cardiopulmonary bypass, impair cardiac function. Although this cardiac dysfunction usually disappears without any after-effects, inotropic treatment is mandatory for a short time. There, however, is no easy way to monitor cardiac output in these small patients. Neither is there much universally recognized objective data available to help choose between these drugs available or between different protocols. Physiologically, infants are not small adults. In the neonatal period, the heart works virtually at its maximum, with little reserve : the stroke volume has a limited capacity to increase because of poor compliance, and the heart rate is high. Cardiac output is therefore rate dependent. To improve therapeutic adjustment, an attempt is made to rationalize the use of inotropic drugs in the postoperative period. Cardiac dysfunction can frequently be recognized already in theatre. It is of paramount importance to exclude faulty surgical repair by measuring the pressures and oxygen saturation in all the cardiac chambers and vessels. The severity of haemodynamic impairment will then have to be defined. As well as the usual clinical criteria (blood pressure, diuresis), the trend in the capnographic curve during a reduction of extracorporeal blood flow rate and acid-base measurements are most helpful. If no further immediate surgery is found to be necessary, the most serious cases are treated by cardiopulmonary support (right to left, or cardiac left to left, or exceptionally biventricular), usually for 1 to 3 h.(ABSTRACT TRUNCATED AT 250 WORDS)