Binding of 99mTc plasminogen on fibrin.

Binding of plasminogen to fibrin was studied in vitro and in vivo using 99mTc Glu- and Lys-plasminogen. Binding of Glu-plasminogen on the clot was not observed in vitro, and in vivo in the dog. Conversely, the binding of Lys-plasminogen to fibrin displays a linear relationship to the concentration of Lys-plasminogen, up to doses exceeding equimolarity; thus suggesting the existence of several Lys-plasminogen binding sites on fibrin. Binding levels were identical, regardless of whether plasminogen was incubated in normal plasma or in plasma devoid of antiplasmin. In the dog, Lys-plasminogen bound specifically to the clot, however, clot sites could not be localized by scintigraphy in the dog or in man.

Evaluation of low molecular weight heparin during and after aortic and carotid surgery: dose finding study.

Forty-four patients undergoing abdominal aortic surgery and twenty-eight patients undergoing carotid surgery were randomly treated with different anticoagulant regimens. During surgery, an unfractionated heparin (UFH) intravenous bolus of 50 IU/kg was compared with a low molecular weight heparin (LMWH) bolus of either 120 IU/kg, 80 IU/kg, 40 IU/kg or 20 IU/kg. Six hours after surgery and for 48 hours, an UFH infusion was compared with an LMWH infusion of either 10,000 IU/day or 6,000 IU/day and then, a single LMWH subcutaneous injection of 3,075 IU was administered. Heparin activity was measured by factor Xa inhibitor and by prolongation of APTT which were studied 15, 30 and 60 minutes after cross-clamping, at the end of surgery and six hours later, and on days 1, 2, 3 and 6. After a descriptive analysis of clinical and pharmacokinetic profiles of each regimen, optimal LMWH treatment is proposed.

Iliac transluminal angioplasty and distal surgical revascularisation can be performed in a one-step technique.

PURPOSE: A few authors have suggested treating double-level atherosclerotic lesions in high risk patients by an association of iliac transluminal angioplasty (ITA) and distal surgical restoration in a two-step technique with an interval of one to three weeks between the two procedures. Previous reports of ITA showed the influence of the quality of the outflow on early results, we therefore decided to perform the two procedures mentioned above during the same operation. METHODS: During a five-year period, 51 patients (42 men, 9 women) underwent an isolated ITA in 32 cases (group I) or associated with a simultaneous surgical reconstruction (group II) in 19 cases. Mean age (56.4+/-12 years versus 63.9+/-11.8 years, p<0.01), frequency of limb-threatened ischaemia (2.6% versus 42.1% p<0.001), and of an ipsilateral thrombosed or severely stenotic femoral artery (20% versus 100%, p<0.001) were significantly higher in group II. In group I (n=32), 45 unique or double iliac lesions (unilateral=25, bilateral=7) including 42 stenosis (>75%) and three thrombosis were treated. In group II (n=19), ITA was performed on unique and unilateral iliac stenosis (>75%) in association with a femoro-femoral bypass (n=4), an ipsilateral femoro-popliteal bypass (n=5) or femoro-tibial bypass (n=3) or an ipsilateral deep or common femoral reconstruction (n=7). RESULTS: Early complications consisted of one haematoma (group I), one death and one iliac restenosis (group 2). After a mean follow-up of 20 months, cumulative patency of groups I and II was respectively 81% and 88% (p=ns), with an increase in the ankle/brachial systolic pressure ratio from 0.73+/-0.14 to 0.92+/-0.14 (p<0.001) in group I, and from 0.57+/-0.15 to 0.84+/-0.12 (p<0.001) in group II. CONCLUSIONS: Early and mid-term results of the one-step technique are similar to those obtained with patients who underwent ITA with good initial outflow. This technique can therefore be recommended in high-risk patients with double-level atherosclerotic lesions including severe iliac stenosis.

Naftidrofuryl in chronic arterial disease. Results of a six month controlled multicenter study using Naftidrofuryl tablets 200 mg.

The study was carried out on patients with intermittent claudication (Fontaine's stage II). The arterial and atheromatous origin of the disease was confirmed and localized by angiography or Doppler velocimetry examination. One hundred eighty-six patients were selected initially. Their pain-free walking distance on a treadmill (at a speed of 3 km/hour and an inclination of 10%) had to be 150-300 m. During the first month all patients received 3 placebo tablets daily. At the end of this run-in period (D-30; D 0) and after checking walking distance stability (allowed variation: +/- 20% between the two measurements) the patients were included in the study. One hundred fifty-four patients were selected and 118 remained during the whole study. The study was designed as a double-blind, using two parallel randomly selected groups. Sixty-four patients received for six months Naftidrofuryl (3 X 200 mg tablets daily with meals); 54 patients received placebo under the same conditions. During this period, clinical and paraclinical examinations were carried out every quarter (D 90 and D 180). After checking the initial homogeneity of the Naftidrofuryl and placebo-groups, the comparison between groups indicates a significant improvement in Naftidrofuryl group after 3 and 6 months of treatment. At the end of the study the observed differences in walking distance with Naftidrofuryl are approximately twice the difference in the reference group (D 90: p less than 0.05; D 180: p less than 0.02). The results of this study indicate that Naftidrofuryl is an efficient pharmacological tool for treatment of patients with chronic arterial disease (Fontaine's stage II).

[Contribution of complementary examinations in the diagnosis and treatment of emboligenic cardiopathies. Retrospective study apropos of 46 cases]. / Apport des examens complémentaires dans le diagnostic et dans le traitement des cardiopathies emboligènes. Etude prospective à propos de 46 cas.

The aim of this prospective study was to assess the value of complementary investigations in the diagnosis and follow-up of embolic heart disease. Forty-six patients having presented a systemic embolism cardiac origin underwent a standard work up which included clinical examination, ECG, chest X-ray and 2D echocardiography. Other investigations were carried out in some patients: CT cardiac scan (11 cases), gamma scintigraphy with Indium III labelled platelets (6 cases) and angiocardiography (12 cases). The diagnosis of an embolic cardiac lesion was made after the standard investigations in 82% of cases. The remaining 18% of cases hall had echocardiographic abnormalities and enable the diagnosis of clinically imapparent conditions: mitral valve prolapse, aneurysm of the interatrial septum, valvular calcification and cardiomyopathy. A potentially embolic mass was visualised in 18 patients; 6 valvular vegetations, 12 left atrial or ventricular thrombi. The other specialised radionuclide, angiographic and CT investigations only confirmed the echocardiographic diagnosis of intravavitary thrombosis. These results were confirmed surgically in 19% of cases. This study shows that complementary investigations especially echocardiography, allow diagnosis of latent embolic cardiac lesions, some of which may benefit from surgical treatment. In addition, potentially embolic intracardiac masses may be visualised, so confirming the origin of systemic emboli. When surgery is not indicated, echocardiography is a good method of following up the results of medical treatment in some of these masses.

[Late complications of abdominal aortic prostheses: false aneurysms and aorta-digestive fistulas]. / Complications tardives des prothèses aortiques sous-rénales: faux anévrismes et fistules aorto-digestives. Stratégie chirurgicale.

Pseudoaneurysms of the abdominal aorta (PAAA) are late complications of aortic reconstruction that occur with an incidence varying from 4.8 to 6.3% associated with an operative mortality of 21 to 35%. Between 1987 and 1994, 16 patients with a PAAA (14 men and two women, with a mean age of 69.5 years, ranging from 55 to 82 years) were treated in our unit. An anastomotic rupture with a pseudoaneurysm diameter varying from 50 to 75 mm was present in five cases (group 1). The eleven other cases were aorto-enteric fistula, isolated in six cases (group 2) and associated with local and/or general sepsis signs in five cases (group 3). The mean interval from the time of the primary aortic graft, which was performed as treatment for aortic aneurysm in six cases and for aortoiliac occlusive disease in 10 cases, and the diagnosis of the PAAA, was 11.3 years. An in situ replacement of the aortic graft with an interposition of the greater omentum was performed in each patient of groups 1 and 2, associated with an enteric restoration in the latter. Group 3 patients were treated by removal of the infected graft with closure of the aortic stump and extra-anatomic bypass. During the post-operative period, five deaths (31%) and one limb amputation (6%) occurred, i.e. one death in group 1 (20%), one in group 2 (17%) and three in group 3 (60%) associated with a limb amputation (20%).(ABSTRACT TRUNCATED AT 250 WORDS)

[Photoplethysmography in chronic venous insufficiency]. / La photopléthysmographie dans les insuffisances veineuses chroniques.

Venous photoplethysmography (P.P.G.) is a non-invasive diagnostic technique using reflection of infrared light on the skin. The record gives a curve analogous to venous pressure. Normally the venous pressure of the leg decreases in response to calf muscle exercise. We have affixed the P.P.G. transducer to the skin above the medial malleolus and have analyzed the recovery half time (T 1/2) on 170 limbs: 49 normal, 82 with superficial venous insufficiency and 39 with deep venous insufficiency. Reference tests were ascending and retrograde phlebography and venous Doppler evaluation. A tourniquet was used to occlude the superficial venous network. T 1/2 without tourniquet is useful to screen limbs with venous insufficiency. T 1/2 with tourniquet differentiates deep and superficial venous insufficiency. P.P. G. can document the rise of deep venous insufficiency in patients with varicose veins and or repermeation of deep veins or post phlebitic syndrome among patients who have had thrombophlebitis.

[Indirect measurement of residual internal carotid pressure by photoplethysmography during the carotid occlusion test]. / Mesure indirecte de la pression résiduelle de la carotide interne par photopléthysmographie lors du test d'occlusion carotidienne.

A non invasive technique for measuring the systolic arterial pressure in the internal carotid artery during common carotid artery occlusion test is described. Its objective is to predict the efficiency of the collateral circulation through the circle of Willis during surgical carotid artery clamping. Photoplethysmographic curves were recorded on two facial areas supplied by the external carotid artery (earlobe and forehead above the center of one eyebrow). The residual carotid artery pressure during carotid clamping was estimated by considering the ratio of determined by the systolic brachial arterial pressure over the amplitude of the best photoplethysmographic curve obtained, multiplied by the amplitude of the photoplethysmographic curves recorded during the percutaneous compression of the common carotid artery. This method was verified on 15 patients (women: 6, men: 9) with carotid lesions, during carotid endarterectomy. The invasive measurement of the systolic pressure in the internal carotid during carotid clamping was compared with the calculated value. This comparison showed a highly significant correlation between the two values (p less than 0.001). Thus, a simple and non-invasive method of estimating the internal carotid systolic pressure during carotid clamping is described, so that the efficiency of the collateral circulation during this period may be assessed before surgery.

[Surgery of the perforating veins of the leg: open and endoscopic techniques]. / Chirurgie des veines perforantes jambières: les techniques à ciel ouvert et endoscopiques.

Surgical treatment of incompetent perforating veins of the leg is best carried out through a sub-aponeurotic approach after localisation by coloured Duplex-Scanning. Open techniques are long established. When there is only one perforator, a short 5 cm approach is centred over the previously localised perforator. In the presence of multiple perforators, an extensive approach is necessary. This usually means a single long incision, situated para-tibially in the Linton approach, postero-medially in the Dodd approach or posteriorly in the Felder approach. The advantage of the last two approaches is that they are situated at a distance from any eventual cutaneous lesion. The approach can also be through several separate oblique incisions (De Palma). More recently introduced, endoscopic techniques have the advantage of reducing the incidence of cutaneous complications such as necrosis or infections and of shortening the duration of hospitalisation. Some authors work with re-usable instruments. The perforators are divided after coagulation (Hauer, Sattler). Others use disposable instruments, insufflate the sub-aponeurotic space and clip the perforators to prevent bleeding (Gloviczki). These techniques are currently undergoing evaluation.

[Infections of vascular prostheses of the abdominal aorta. Diagnostic and therapeutic problems]. / Les infections de prothèses vasculaires de l'aorte sous-rénale. Problèmes diagnostiques et thérapeutiques.

UNLABELLED: Aortic graft infection is one of the most serious complication of vascular surgery. While the incidence of such infections has declined over the years, it continues to be associated with high mortality and high rates of limb loss. Graft implanted in the inguinal area have a higher rate of infection than those that lie entirely within the abdomen. Infection of the intraabdominal extremities of vascular grafts is most frequently associated with prostheto-enteric fistula. DIAGNOSIS AND TREATMENT: Despite the many available sophisticated imaging techniques diagnosis remains difficult, particularly with intra-abdominal grafts because of nonspecific clinical and imaging findings. A variety of approaches to aortic graft infection have been proposed and optimal treatment usually requires an association of systemic antibiotic administration with surgery. Removal of the entire infected graft is often necessary for cure and there are only few situations in which conservative treatment is acceptable. A careful identification of the infecting microorganisms and in vitro susceptibility testing are essential for successful therapy. PREVENTION: Prevention consists in a strict adherence to principles of asepsis and the use of prophylactic antibiotics in vascular surgery. The use of antibiotics-bound knitted grafts has been recently proposed.

[Comparative study of color Doppler echocardiography and arteriography in carotid disease]. / Etude comparative de l'écho-Doppler couleur et de l'artériographie en pathologie carotidienne.

The increasing accuracy of duplex scanning and the morbidity linked to angiography have led some authors to discard the latter when exploring patients with severe carotid lesions. In order to fully define the respective information obtained by these two explorations and to determine their impact on therapeutic decisions, were examined the file of 122 patients. The comparative analysis of preoperative color duplex scanning and angiographic results, the latter used as a reference, showed a sensitivity of 97% and a specificity of 57%, concerning the ability to detect a significant carotid artery stenosis. On the other hand, color duplex scan and angiography had the same accuracy to screen the presence of an ulceration, but could only detect two third of the ulcerations observed on pathologic examination of 94 surgically-treated patients. At last, angiography was more reliable in detecting a carotid excess of length (p < 0.001), in the identification of internal carotid thrombosis and of dissection on dysplasic arteries. In conclusion, we propose a selective indication of angiography in case of suspicion of proximal periaortic arterial lesions, of complications on dysplastic arteries, of detection of pre-thrombotic carotid lesions and in order to confirm the existence of significant stenosis in asymptomatic patients.

[Recurrence following surgery of the gastrocnemius veins]. / Récidives après chirurgie des veines jumelles.

Routine preoperative investigation of chronic venous insufficiency of the lower limbs with echo-Doppler has brought to light the presence of reflux into the gastrocnemius veins in almost 30% of the patients. Surgical treatment to stop this reflux consists in dividing the gastrocnemius vein flush to the popliteal vein. Early postoperative investigation of patients operated on in this way, who are symptomless and with no residual varices, has revealed the presence of persistent, symptomless, postoperative reflux into the gastrocnemius veins. One hundred and six patients were checked six months postoperatively by Duplex Doppler scanning. On the basis of the anatomical and functional findings, postoperative incompetence of the gastrocnemius veins could be classified into several types according to the cause: 1. Persistence of a complete and incompetent gastrocnemius vein, probably missed at operation: 16 patients (15%). 2. Neoangiogenesis: 11 patients (10%). 3. Persistence of an incompetent lower gastrocnemius perforating vein: 17 patients (16%). Thus, echography has revealed that in 44 lower limbs out of 106 (42%) in which the gastrocnemius veins were operated on, six months postoperatively evidence of reflux into the gastrocnemius venous network was present. All these patients were asymptomatic. In a sub-group of 48 lower limbs which had an interval Doppler check at 2 months: 6 already showed a reflux (12.5%), in 11 the gastrocnemius reflux appeared between the second and the sixth months (23%), 31 showed no reflux at 6 months (64.5%). From these findings, certain rules on the surgery of the gastrocnemius veins have been drawn up.

[Per and early postoperative use of low molecular weight heparin in carotid surgery]. / Utilisation per et postopératoire précoce des héparines de bas poids moléculaire en chirurgie carotidienne.

The goal of this study was to evaluate per and postoperative use of nadroparin during carotid surgery with mortality and neurologic morbidity as primary end points. From January 1995 to December 1999, 237 procedures were performed on 215 patients for isolated carotid surgery; 57% were symptomatic. Surgery was performed under general anesthesia. Before clamping, patients received an intravenous bolus of 70 UI/kg of nadroparin. Shunting was used in 40% of patients. Postoperatively, from the 6(th) hour, nadroparin was given subcutaneously, 2,850 UI or 3,800 UI every 12 hours depending on the patient weight (less or more than 70 kg). The only biologic surveillance was platelet count twice a week. Antiplatelet drugs were given at day 2. Completion Duplex scan was performed before day 30. Seven postoperative ischemic strokes (3 non disabling) occurred including one fatal stroke. Another patient died at day 25 from inaugural duodenal bleeding due to pancreas cancer. The 30 days stroke or death rate was 3.37% (5.92% in symptomatic; 0% in asymptomatic). No hemorrhagic stroke occurred. Four patients were reoperated for cervical hematoma (1.68%). No thrombocytopenia occurred. Duplex scan, performed on 235 operated carotid arteries, showed 2 asymptomatic carotid thromboses. No other cardiovascular complication was found on clinical data. These results are comparable to published literature data in prospective as well as retrospective studies. Per and postoperative use of nadroparin in carotid surgery gave results similar to previously published reports in terms of mortality, neurologic morbidity and hematoma. Its easy use, needing only 2 injections a day and platelet count, with a reduction of the risk of heparin-induced thrombocytopenia make the use of nadroparin very attractive during the perioperative period.

[Laparoscopic transperitoneal replacement of the abdominal aorta with left renal artery reimplantation: experimental study on pigs]. / Remplacement laparoscopique transpéritonéal de l'aorte abdominale avec réimplantation de l'artère rénale gauche.

OBJECTIVE: To study the feasibility and the tolerance of a combined laparoscopic transperitoneal aortic and renal restoration performed on animals. METHODS: Six pigs (mean weight: 79.5 kg, range 73-86) underwent laparoscopic replacement of the abdominal aorta using a 6-mm Dacron(R) graft, with direct reimplantation of the left renal artery. The study protocol was approved by the Advisory committee of Animal Ethics. The animal was placed supine on the operative table with a pillow under the lumbar region in order to raise the aortic area. A first midline, 10-mm diameter trocar was placed under direct vision, 5 cm above the pubis and allowed the insufflation of a 12-mm Hg pneumoperitoneum. One 30 degrees optic was used during the intervention. The pig was then tilted to a 30 degrees Trendelenbourg's position and two other 10-mm trocars were introduced 5 cm medially to the right and left antero-superior iliac spines ). Four other 10-mm incisions were necessary for introduction of an intestinal retractor, a suction-irrigation device and two laparoscopic aortic clamps. RESULTS: The procedure was performed in all animals in a mean operative time of 320 min (292-366), including ): - a time for aortic and renal artery dissection of 104 min (90-120), - a supra-renal aortic clamping time of 221 min (180-276), - a time for confection of proximal and distal aorto-prosthetic anastomosis of respectively 59 min (40-75) and 64 min (50-80), - a time for the left renal artery reimplantation of 72 min (40-140). Average blood loss was 525 ml (250-1050), and the mean pre and postoperative hemoglobin and pH values were 9.9 g/dl (8.9-10.7) versus 9.4 g/dl (8.5-11.3) and 7.36 (7.31-7.38) versus 7.30 (7.21-7.43) respectively. An angiogram ) performed before the sacrifice of animals showed a wide patent anastomosis in 18 (56%) cases, a<50% stenosis in 4 cases (22%), a > 50% stenosis in 1 case (5%) and a thrombosis of the first three renal artery restorations (17%) probably due to insufficient intraoperative heparinization. CONCLUSION: This experimental study shows the feasibility of laparoscopic transperitoneal abdominal aortic restoration with re-implantation of the left renal artery (fig. et ). The techniques of arterial sutures must be improved in order to decrease aortic and renal clamping times.

[Thoracoscopic bypass from the descending thoracic aorta to the femoral artery. Experimental study and clinical application]. / Pontage thoracoscopique entre l'aorte thoracique descendante et l'artère fémorale. Etude expérimentale et application clinique.

OBJECTIVE: Descending thoracic aorta to femoral artery bypass (DTAFB) has demonstrated usefulness in the treatment of aorto-iliac occlusive disease but related morbidity and mortality are not negligible. We wanted to determine the feasibility of thoracoscopic DTAFB and to report our clinical experience. MATERIAL AND METHODS: An experimental study was performed on 8 pigs in helicoidal position under general anesthesia with right selective ventilation ). Three trocars were inserted and the descending aorta was dissected ). After tunnelisation of a 6 mm graft, a lateral aortic anastomosis was thoracoscopically performed ) then femoral anastomoses were made. At the end of the procedure, an angiogram and then an autopsy were performed ). Subsequently, three patients were operated, two for thrombosis of a previous aortobifémoral bypass and one for infrarenal aortic hypoplasia. Dissection and graft tunnelisation were performed thoracoscopically ). Then, the aortic anastomosis ) was constructed through a left lateral minithoracotomy (10 cm). RESULTS: One pig died during surgery of acute lung oedema due to the difficulties of selective ventilation. Excluding this case, the average times of surgery and of dissection were respectively 246 (205-325) and 68 minutes (50-90). The average aortic clamping and anastomosing times were 135 (105-220) and 120 minutes (80-210) ). Three aortic tears were noted; one was repaired. Angiogram was normal 5 times; one pig had a minor stenosis and a leak, and another one had a leak. All the anastomoses were patent without stenosis at autopsy; no organ lesion was found. In humans, the procedure was performed with simple postoperative course in 2 patients and a conversion (20 cm long thoracotomy) was necessary for the third due to poorly supported selective ventilation. CONCLUSION: Totally thoracoscopic DTAFB can be performed in pigs. In clinical practice, we recommend the use of a mini thoracotomy. This way, the aortic anastomosis can be performed with aortic clamping time under 30 minutes, reducing the risk of spinal cord ischemia. These results allow to propose mini invasive thoracoscopically assisted DTAFB for the patients for whom laparoscopic access of the abdominal aorta appears to be difficult (calcified aorta, hostile belly.).

[Laparoscopic replacement of the abdominal aorta. Experimental study in the pig]. / Remplacement laparoscopique de l'aorte abdominale. Etude expérimentale chez le porc.

BACKGROUND: Progress in abdominal laparoscopy led us to study end-to-end anastomoses performed laparoscopically. METHOD: An experimental protocol in 10 castrated male pigs weighing 74-95 kg was approved by the ethics committee. After conventional anesthesia, each animal was positioned in lateral decubitus and a retropneumoperitoneum was created. CO2 inflation was maintained at 14 mmHg for insertion of 3 trocars, 5 to 10 mm width. The entire infrarenal aorta was dissected and resected with insertion of a 6 mm dacron prosthesis. Postoperative arteriography was performed in all cases. The animal was sacrificed for direct examination. RESULTS: One animal died during anesthesia induction and the entire protocol was conducted in 9 animals. Mean operative time was 397 min (305-535 min) including a mean 123 min (65-150) for aortic dissection, 82 min (30-155) for proximal anastomosis and 70 min (45-105) for distal anastomosis. Total blood loss varied from 100 to 450 cc (mean 252 cc). Mean difference between pre- and postoperative hematocrits was 4% (0-6%). Among the 18 aortic anastomoses performed, arteriography showed one with moderate leakage and one anastomotic thrombus. Stenosis > 50% was found in 4 cases and < 50% in 4 cases. Analysis of the different operative parameters showed a learning curve with decreasing operative time and improved quality of the anastomoses. CONCLUSION: This study demonstrates the feasibility of aortic reconstruction via retroperitoneal laparoscopy in the animal. This procedure could be introduced in man.

[Manipulations of cervical vertebrae and trauma of the vertebral artery. Report of two cases]. / Manipulations des vertèbres cervicales et traumatisme de l'artère vertébrale: à propos de deux cas.

Vertebrobasilar-distribution stroke is a rare but sometimes severe complication of chiropractic neck manipulation. We report two patients with dissections of the vertebral arteries authenticated two and six days after the cervical manipulation. In the first case, a Wallenberg's syndrome occurred due to a dissection of the right intracranial vertebral artery; the patient was treated with anticoagulant therapy but little improvement of the disorder was noted. The second patient had transitory neurologic manifestations which led to the discovery of an intimal tear of the ostium of the right vertebral artery with a floating clot. Further embolic complications were avoided by performing a venous bypass between the right common carotid and the vertebral artery at the base of the skull. Therapists should be aware of vertebrobasilar complications after spinal manipulations and should ask for early explorations (brain CT, cerebral angiography) to institute rapidly the most appropriate treatment.

[Morphologic study of different types of venous grafts. Correlation trial with parietal fibrinolytic activity]. / Etude morphologique de différents types de greffons veineux. Essai de corrélation avec l'activité fibrinolytique pariétale.

In this experimental work, morphological aspects of different vein grafts were studied using both light microscopy, transmission electron microscopy and scanning electron microscopy. The correlation was made with their fibrinolytic activity ; 21 dogs were operated on under general anaesthesia ; "venous grafts" (perfusion of the vascular segments with venous blood) were performed by excision of the femoral vein with reanastomosis at the same site (protocol P1). "Arterialised grafts" (perfusion of a segment of vein with arterial blood at arterial pressure) were performed according to two protocols : P2 in which a segment of femoral artery was replaced with a segment of reversed femoral vein ; P3 in which a segment of femoral artery was by passed with the femoral vein left in situ after destroying the valves using a Fogarty balloon without damage of the intima. The factors affected by surgery are, therefore, disconnection of the vasa vasorum by excision of the vessel in protocols P1 and P2 and increased oxygenation and luminal pressure in protocols P2 and P3. In all the cases, endothelial cells retained the morphological characteristics of venous endothelium. However, the vein grafts in the arterial circulation were thickened and the fibrinolytic activity was changed. Pathogenic mechanisms of these changes are discussed.

[Trial of a new technic of transcutaneous diaphragmatic electrostimulation in man]. / Essai d'une nouvelle technique d'électrostimulation diaphragmatique transcutanée chez l'homme.

A new method of diaphragmatic pacing by transcutaneous electrical stimulation, using alternative currents with frequency and amplitude modulations, was tested in 12 subjects: 3 were normal and awake (group I); 4 were studied in acute respiratory failure while under mechanical ventilation and central apnea (group II) and 5 were studied while anaesthetized for peripheral venous surgery and breathing spontaneously (group III). Stimulation was performed either during spontaneous ventilation (groups I and II) or during short periods of respiratory depression (group III). Tidal volume was measured by pneumotachography. A positive correlation was found between stimulus intensity and inspired volume. This effect was not due to voluntary control alone, since diaphragmatic stimulation could support 24% of the theoretical minute ventilation in group II subjects and 64% in group III subjects. These preliminary results demonstrate the relative efficacy of this new method of diaphragmatic pacing using computerized alternative currents.

[Selective indications of cardiac studies before aortic surgery]. / Indications sélectives des explorations cardiaques avant chirurgie aortique.

OBJECTIVES: There is no consensus on heart explorations required before infra-renal reconstruction surgery of the aorta. We proposed a selective approach in 81 consecutive patients undergoing elective surgery. METHODS: Four clinical criteria were recorded: age over 70 years, diabetes mellitus and a clinical history of coronary artery disease or heart failure. RESULTS: For 23 patients (group 1), none of the criteria were positive. Surgery was performed in all without prior exploration. There was one death (4.8%) and one post-operative cardiac event (4.8%) in this group. The 58 other patients (group 2) had at least one of the criteria and had complementary heart explorations before surgery. There were 2 deaths (3.4%) and 5 cases of cardiac morbidity (8.6%) in this group. CONCLUSION: The lack of any statistical difference between the two groups with and without risk criteria has led us to propose selective indications for preoperative explorations based on specific clinical criteria.