Effect of positive external pressure on calf volume and local venous haemodynamics.

The pressure external to the calf was increased suddenly in 11 normal subjects and the resulting change in calf volume (considered to be mainly a change of calf vein blood volume) was followed using a mercury-in-rubber strain gauge. For a small increase of pressure the volume decreased exponentially and increased linearly when the pressure was suddenly released. A simple theory was developed which treats the calf veins as a single volume with a single compliance and a single outflow resistance. Using the theory, the following average results were obtained from measured values: effective venous compliance 1-1%kPa (SD 0.3); effective venous outflow resistance 3.8 s kPa/% (SD 1-3); and total flow into the veins from themicrocirculation 0.054%/s (SD 0.020) (% refers to a change in volume expressed as a percentage of the initial volume of the calf). The significance of the findings is considered with special reference to the occurrence of calf vein thrombosis.

Pathological aspects of carotid plaques. Surgical and clinical significance.

We examined 134 carotid plaques microscopically in 125 consecutive patients, and found 21 (15.7%) had simple fibrous plaques versus 113 (84.3%) complicated plaques. The following plaque characteristics were present: intraplaque hemorrhage (73 plaques), ulceration (83 plaques), fresh thrombus (93 plaques), and recanalized thrombus (22 plaques). An average of 2.4 characteristics were observed in each complicated plaque. The only significant (p less than 0.05) clinico-pathologic correlation was the presence of fresh thrombi, found in 80% of the plaques from patients with a previous transient ischemic attack, in 93% of those with nonfocal neurologic symptoms, and in 80% of those with amaurosis fugax. Analysing the localization of the fresh thrombus (mural or intraluminal), we found that fresh thrombus in symptomatic plaques was most frequently (NS) (71 to 77%) exposed to the vessel lumen. Ulceration without fresh thrombus, plaque hemorrhage and recanalized thrombus were also found in a considerable number of asymptomatic patients, of whom 85% (33/41) presented a form of complicated plaque.

The assessment of chronic venous obstructions by non invasive haemodynamic studies and imaging with Kr-81 m venography.

We study the sequelae of venous obstructions (from 15 days to several years after the thrombosis) by non invasive haemodynamic methods: Doppler velocimetry and leg plethysmography. We describe a simple physical model which permits the calculation of the leg outflow resistance from the venous occlusion plethysmography data. A radionuclide imaging of the veins is also recorded by a gammacamera during the perfusion of the limbs with Kr-81 m. This flexible technique appears suitable to analyse persistent ilio-femoro-popliteal obstructions. The results of the Doppler investigation are well related to the phlebograms. The outflow resistance of the leg depends mainly on the duration of the persistent obstruction. Recent obstructions are generally highly resistive but the level of the resistance is becoming close to normal with time (after two years).

Effect of exercise on the leg distribution of C15O2 and 15O2 in normals and in patients with peripheral ischemia: a study using positron tomography.

In order to evaluate regional muscle blood flow and oxygen utilization, we study with positron emission tomography (PET) the distribution of C15O2 and 15O2 in 17 subjects: 5 normals (24 +/- 3 years) and 12 patients (63 +/- 13.5 years). C15O2 and 15O2 are inhalated with a steady-state technique. Positron tomograms are recorded in supine position at the greatest diameter of the leg. Exercise consists in simultaneous ankle flexions. In all normals, C15O2 and 15O2 are distributed homogeneously and symmetrically in both legs. At rest, they concentrate in the region of vascular pedicle. After exercise, C15O2 and 15O2 are electively distributed in the anterolateral region of the leg. In patients, this pattern of distribution is similar but asymmetrical. Moreover, the regional uptake of C15O2 and 15O2 often dissociates. In conclusion, C15O2 and 15O2 allow to study repeatedly muscle blood flow and oxygen utilization in patients with peripheral ischemia, both at rest and after exercise. The broad spectrum of pathological changes observed in this study needs further metabolic investigations.

Combined study of hyperemia after arterial occlusion and exercise by an isotopical test and a Doppler-ultrasonic method.

Postischemic hyperemia was studied in normal and pathologic limbs by an isotopical method, which measures the delay and the rate of appearance of tagged serum-albumin in the foot after release of an arterial femoral occlusion (T in seconds). The postexercise hyperemia was assessed by the follow-up of the ankle arterial pressure drop (deltaP). deltaP was positively correlated to the logarithm of T in the absence of proximal arterial lesions. The correlation vanished in the presence of an aortoiliac occlusive disease. Therefore we conclude that the isotopical test can be used to assess selectively the capacity of hyperemia of the arterial network below the inguinal ligament.

The quantitation of blood flow/metabolism coupling at rest and after exercise in peripheral arterial insufficiency, using PET and 15-0 labeled tracers.

Regional blood flow and oxygen uptake of the lower limbs were studied in 11 patients with arterial insufficiency (10 with severe unilateral, 1 with bilateral intermittent claudication). Regional muscle blood flow (F), oxygen consumption rate (R), and oxygen extraction fraction (E) were evaluated by positron emission tomography (PET) and bolus inhalation of C15O2 and 15O2 by the patient. Tomograms were recorded at the greatest diameter of legs, at rest and ten minutes after a treadmill walk test leading to the development of ischemic pain in the affected leg. In 5 patients, F and E were correlated with the results of occlusive venous strain gauge plethysmography and with the measurements of blood gases in one brachial artery and in the femoral vein of the affected limb. Blood flow values measured at rest and after exercise by PET were poorly correlated with the plethysmographic findings. This may be because PET does not interfere with flow as venous occlusion plethysmography does in low peripheral pressure conditions. The results show that F, R, and E were not significantly different in normal and pathologic legs at rest. The values of F and R were significantly higher in pathologic than in normal lower limbs, ten minutes after exercise, whereas E was not significantly altered by exercise at any side. This suggests that, during the recovery from a walk test, the delayed increase in oxygen uptake is proportional to the delayed hyperemia in the ischemic muscles ("oxygen debt") and probably not linked to a luxury perfusion.

Assessment of flow and oxygen delivery to the lower extremity in arterial insufficiency: a PET-scan study comparison with other methods.

The authors studied muscular blood flow (F), oxygen consumption rate (R), and oxygen extraction fraction (E) in 5 patients suffering from severe intermittent claudication (stage II). They applied the bolus technique of H2150 and 1502 with a detection by positron emission tomography (PET). Tomograms were recorded at the greatest diameter of the calves, at rest and ten minutes after a treadmill walk test leading to the development of ischemic pain in the affected extremity. F and E data were compared with the values obtained by more usual methods, namely occlusive venous strain gauge plethysmography and femoral venous blood sampling. During the study, these patients received naftidrofuryl, a vasodilatator drug, in an intravenous dose of 600 mg diluted in 250 mL saline infused over a six-hour period in a placebo-controlled, double-blind, crossover protocol (two consecutive experiments, a week apart). The results showed that all blood flow values measured at rest and after exercise by PET were in close correlation (r = 0.71) with the plethysmographic findings. The agreement between the two methods of measuring blood flow was less obvious with an Altman's presentation of the data: there was a tendency to measure higher values with PET scan. Concerning E, the correlation was poor at rest. After exercise, the values were more elevated with PET and no correlation was found with blood samples. The authors found no significant effect of naftidrofuryl either on flow or metabolic data.

Giant cell arteritis (Horton's disease) of the axillary artery--case reports.

The authors recently observed 2 elderly female patients with ischemic pain of the upper extremity as the first manifestation of giant cell arteritis. They presented with rest pain of both upper extremities and even gangrene of the thumb in 1 case. Subclavian and radial pulses were absent while peripheral pulses in the lower limbs were preserved. The angiography was so typical that the diagnosis of inflammatory arteritis was made, despite negative temporal artery biopsy. The patient with thumb gangrene was successfully operated on, the occlusive axillary lesions being bypassed by a long venous carotid humeral bypass graft. A biopsy of the axillary artery showed a granulomatous lymphoplasmocellular infiltration. A high-dose corticotherapy (24 mg daily) was begun in both cases, with dramatic improvements of general state, lowering of the erythrocyte sedimentation rate, and even reapparition of a reduced radial pulse in 1 patient. The authors discuss the incidence, symptoms, diagnosis, and treatment of systemic giant cell arteritis, with special attention to extracranial involvement. These case reports may broaden the knowledge of the diverse manifestations of giant cell arteritis and of its systemic character with widespread vascular involvement.

[Intermittent claudication. Introduction to clinical diagnosis]. / Claudication intermittente. Introduction à la clinique.

The history and the physical examination are still at the basis of the approach of the patient suffering from intermittent claudication. The history makes clear the specific symptom and its localization. The evolution of the disease, the social and professional handicap are defined. Other troubles and other localizations of the vascular disease are recognized and the nature of the risk factors etablished. The physical examination indicates the pattern and the distribution of the vascular lesions and orientates the pathogenic investigations. A rough assessment of the insufficiency of the cutaneous and muscular circulation is also possible.

Application of a simplified physical model to the plethysmographic study of the leg venous outflow.

We describe a simplified physical model of the leg venous outflow. It features an apparent compliance C and outflow resistance R. The venous volume accumulated during a venous occlusion discharges after the release of the compression following an exponential curve (T = time constant = RC). This model fits the curves obtained by strain gauge plethysmography in normal legs and in limbs suffering from chronic venous obstructions. The values for R, C and T are calculated from the plethysmographic measurements. The limbs with chronic obstructions differentiate themselves from the normal mainly by an increase of R but some limbs show values close to normal likely due to a compensation (collaterals or partial recanalization). T (prolonged) and C (decreased) are less affected by chronic venous obstructions. The diagnostic score of this mode of analysis is better than the usual graphic determination of the maximum venous outflow (MVO).

[Venous plethysmography in a sitting position]. / Pléthysmographie veineuse en position assise.

We studied the venous capacity of the lower limbs by strain gauge plethysmography during venous occlusion (delta v60) and by a dependency test (delta v postural) (from the supine to the sitting position). We were also interested by the performance of the calf musculovenous pump, assessed in two positions: sitting and standing (delta v exercise). The volume changes are increasing when we consider limbs with sequelae of deep vein thrombosis, normal lower limbs and extremities with primary varices. delta v60: 2.13%, 2.84%, 4.24%; p less than 0.01. delta v postural: 1.32%, 1.94%, 3.66%; p less than 0.01. delta v exercise: 0.48%, 1.47%, 2.09%; p less than 0.01. The study of the expelled volume during calf muscle exercise is easier in the sitting than in the standing position and it leads to a better discrimination between normal limbs and limbs suffering from sequelae of deep vein thrombosis. The dependency test with measurement of the venous capacity when going from the supine to the sitting position (with the leg dependent) and the assessment of the calf muscles pump, also in the sitting position, are the basis of a simple approach to the quantitation of venous insufficiency.

[Arterial pathology of the limbs. Tests for hyperemia]. / Pathologie artérielle des membres. Epreuves d'hyperhémie.

We consider the walk test on the treadmill (ET), and the postocclusive reactive hyperemia (HR). The determinations are limited to the peripheral pressures measured by the sphygmomanometric-Doppler technique. It is the method of choice for diagnostic purposes, but is necessary only for selected cases. For epidemiology, HR is interesting because it is simple to apply and the sensitivity and specificity to recognise moderate obstructions is good. The determination of the ankle pressure at rest is generally enough in the routine practice. It is reproducible and safe. ET may be applied in certain conditions taking into account some problems of interpretation due the complexity of the phenomenon.

[Value of the treadmill exercise test for long-term monitoring of lower-limb arteriopathies]. / Valeur de l'épreuve d'effort sur tapis roulant comme moyen de surveillance à long terme d'une artériopathie des membres inférieurs.

The use of the treadmill exercise test is envisaged only as a means of chronic surveillance of the arteriopathy. The walking distance measured in this way is a complex factor to analyze due to interference of non-vascular phenomena and the effect of training. Manometric data (distal arterial pressure, normalized by determination of the distal pressure/central pressure quotient expressed as percent) were collected during recuperation. Variability (of the order of 18% after 5 min) was studied and compared with that of manometric data at rest (approximately 10%). Fifty-one unoperated patients with arteriopathy were studied prospectively one year after their first visit, and an attempt made to establish a clinical judgement, as to the course of the disease, on the basis of hemodynamic tests, taking into account their variability. Examination at rest is usually sufficient for a valid clinical judgement to be made. However, certain types of treatment such as transluminal angioplasty produce effects that appear to evaluate it with greater precision by examination of dynamic data. Certain specific cases also reveal enhanced sensitivity of variables recorded in hemodynamic parameters after effort. In these cases both manometric and femoral Doppler signal data should be studied.

[Musculo-venous pump in the elderly]. / La pompe musculo-veineuse de la personne agée.

We study the musculo-venous pump in an elderly population, free of venous disease, by use of a digitized photoplethysmograph. We measure the venous refilling time (To) and the venous drainage (Vo) during active and passive movement. In the first part, we measure Vo and To during active and passive ankle flexions among 17 patients (34 limbs) aged 82.2 years. These variables are compared to the results of the same measurements obtained among 15 young adults aged 45.1 years (30 limbs). We find that To and Vo are significantly lower in the oldest population (To j 35.9 +/- 4.8 sec, To aged 16.1 +/- 5.2 sec, p < 0.001, Vo j 4.98 +/- 1.1%, Vo ag 2.97 +/- 1%, p < 0.001). In the second part of this work, a passive massage of the calf is substituted to the ankle flexions. This technique is applied to 19 elderly people aged 80.4 years (37 limbs) compared to 6 young adults aged 24 years (12 limbs). In these conditions the comparison is no more in favour of the younger group (To j 37 +/- 7.5 sec, To ag 30.6 +/- 4.1 sec, Vo j 4.03 +/- 1.5%, Vo ag 3.8 +/- 0.06%). The values measured in the elderly group are in the range of normal values. We conclude that senescence does not alter the venous system itself. The present work confirms the influence of extravascular factors as muscles, understanding and coordination of the motions, articular flexibility, on the performance of the musculo venous pomp. As far as possible, the muscular and articular activity has to be encouraged in elderly people in order to reduce the venous stasis.

[Effect of the frequency of neuromuscular electric stimulation of the leg on femoral arterial blood flow]. / Influence de la fréquence de stimulation neuromusculaire électrique de la jambe sur le débit artériel fémoral.

In a previous work we have demonstrated that the transcutaneous neuromuscular electrical stimulation of the muscles of the leg in the human increases largely the arterial femoral blood flow. This elevated flow is stable during the stimulation. The present work deals with the influence of the frequency of the stimulation on the level of this hyperaemia. The neuromuscular electrical stimulation is applied to the internal and external branches of the sciatic nerve in order to stimulate the whole muscles of the leg and the foot. The stimulus is yielded by a Compex stimulator for seven minutes with frequencies in random order between 3 and 15 Hz. The intensity of the current (mean: 31 mA) is set up at such a level to increase blood flow by at least 100% at 5 Hz. The femoral arterial flow velocity and the pulsatility index are assessed during the last minute of the stimulation by a duplex ultrasound method. The peripheral vascular resistance is calculated on the base of the femoral blood flow and the mean arterial pressure. Seven healthy volunteers are studied (6 males and one female, aged 26.9 years, +/- 6.9). The haemodynamic variables are recorded at rest (table I). We observe a linear increase of the blood flow with increasing frequencies of stimulation (181% of the rest value at 3 Hz and 276% at 9 Hz) (fig. 1).(ABSTRACT TRUNCATED AT 250 WORDS)

[Sequelae of unilateral deep venous thrombosis in plethysmography of the calf]. / Etude des séquelles de thrombose veineuse profonde unilatérale par pléthysmographie du mollet.

Twenty four patients suffering from unilateral venous disturbances revealed by Doppler and secondary to a deep venous thrombosis were examined. The calf venous haemodynamics was analyzed by use of a strain-jauge plethysmograph. We determined the increase in venous volume due to the inflation of a thigh pneumatic cuff (pressure at 20, 40 and 60 mm Hg; delta V20, delta V40, delta V60). The maximal venous output (Vout) was measured after a quick release of the 60 mm Hg pressure. The maximal venous drainage (VMM) was assessed during a rhythmic exercise (tiptoeing) while standing; delta V20, delta V40 and delta V60 were nearly constantly reduced on the abnormal side (t of Student respectively 3.49; 6.09 and 5.07). Vout dropped proportionaly to delta V60. Some abnormalities due to valvular insufficiency were frequently present in the beginning of the inflation curve at the level of the abnormal limbs. VMM was nearly always largely decreased on the affected side (t = 5.43). The unilateral flow disturbances displayed by the Doppler were regularly going with abnormalities of the capacitive system, well demonstrated by comparison with the non-affected limbs.

[Scintigraphic study (81mKr) of venous return activation using intravenous dihydroergotamine]. / Etude scintigraphique (81mKr) de la dynamisation du retour veineux par la dihydroergotamine intraveineuse.

We study by 81mKr radionuclide phlebography 13 normal lower limbs and 22 limbs suffering from sequelae of deep vein thrombosis. We assess the spontaneous venous return and the effect of an intravenous injection of 0.5 mg dihydroergotamine (DHE), a powerful venoconstrictor agent. The phlebograms are analysed on a morphological basis. Dynamic data are also collected: the delay of arrival of the radioactivity at the groin and the regional radioactivity level at steady state (during the steady 81mKr perfusion). This segmental radioactivity is a positive marker of the venous stasis because it increases when the venous system dilates and when the flow goes down. It is normalized with regard to the radioactivity measured in the proximal segment (lower vena cava and proximal iliac vein). The influence of DHE on the delay of arrival of the radioactivity in the groin is variable: it is regularly and significantly shortened in the normal limbs (mean decrease of 6.5 s, table II). The segmental radioactivity is relatively low among these limbs (2.76 at the pelvic level, 9.68 at the high, tables IV and V). It drops significantly with DHE in all segments (tables IV and V: -44% in the pelvic veins, -57% in the great saphenous vein and -46% in the femoral tract). The post-thrombotic limbs showing spontaneously an abnormal deep network are characterized by a high radioactivity level (total in the high: 14.25, deep system 5.70 and 8.55 in the saphenous vein, table V). This segmental total radioactivity does not decrease significantly under the influence of DHE; even more it increases in the deep tract (+24%, table V).(ABSTRACT TRUNCATED AT 250 WORDS)

[Study of iliac arterial axes by Doppler ultrasonography during hyperemia induced by walking and arterial occlusion]. / Etude des axes artériels iliaques par ultrasonographie doppler lors de l'hyperémie provoquée par la marche et par l'occlusion artérielle.

We measure the pulsatility index (IP) of the femoral artery by CW-Doppler on 51 limbs, after a treadmill exercise and during a postischemic reactive hyperemia. The pulsatility index (IP) is calculated from the analogic curve produced by a CW-Doppler velocimeter (DUD 400) following a previous work (3). The walking test is carried on until an intermittent caludication is achieved. The ultrasonic curve is recorded after two minutes of recuperation. The hyperemic test follows the application for one minute of a suprasystolic thigh arterial tourniquet. A significant iliac lesion is suspected when IP drops below 1.2 after exercise (3). The IP levels measured during both tests (exercise and reactive hyperemia) are well correlated (r = 0.89). The concordance is achieved among 46 limbs. There is no agreement in 5 cases. IP is lower (less than 1.2) during the reactive hyperemia and higher after exercise (greater than 1.2) in 4 cases. The walk test demonstrates a lesion when the postischemic test is negative in one single case. The CW-Doppler ultra sonography of the femoral artery after the application of a tourniquet is therefore a sensitive method to investigate the iliac flow tract. This technique may be applied on patients enable to walk on the treadmill.

[Regional blood flow and oxygen consumption in the leg muscles of normal subjects and in those with arterial insufficiency. Study of the distribution of C15O2 and of 15O2 using positron emission tomography]. / Débit sanguin régional et extraction de l'oxygène dans les muscles de la jambe chez le sujet normal et l'insuffisant artériel. Etude de la distribution du C15O2 et de l'15O2 par tomographie à émission de positons.

We first studied the distribution of radioactivity during continuous inhalation of C15O2 and 15O2 in traverse tomograms of the greatest diameter of legs, at rest and immediately after exercise (ankle flexions). C15O2 and 15O2 were distributed homogeneously and symmetrically in both legs of normal subjects at rest. The activity accumulated in the anterolateral region after exercise. In patients, this pattern of distribution was similar but asymmetrical, depending on the arterial pathology. No systematic distribution of either C15O2 or 15O2 was observed. In a second step, we studied quantitatively blood flow (F), oxygen uptake (R) and oxygen extraction (E) in 11 subjects: 5 normals (23 +/- 1 years) and 6 patients (60 +/- 11 years) suffering from unilateral intermittent claudication. We used the bolus inhalation technique of C15O2 and 15O2. In the normal leg at rest, ranges were 2.5 to 8.0 ml/min.hg for F, 0.9 to 21.3 mumol/min.hg for R and 3.6 to 33.4% for E. In the pathological leg at rest, ranges were 3.7 to 11.3 ml/min.hg for F, 3.8 to 10.6 mumol/min.hg for R and 7.1 to 24.5% for E. After exercise, ranges were 6.4 to 62.8 ml/min.hg for F, 66.0 to 386.3 mumol/min.hg for R and 29.2 to 89.5% for E in both legs. There was no straight difference between normal and pathological legs soon after exercise. This study allows us to expect that the demonstration of such a difference implies a longer delay of data acquisition following the slow post-ischemia recovery.

[Clinical approach to the patient with polyvascular disease]. / Examen du patient polyvasculaire.

The history and the physical examination are important steps in the clinical approach to the polyvascular patient. They are the foundation of a rational diagnostic and therapeutic management. Complementary investigations are nevertheless necessary. Ultrasonography has become an essential complement to the physical examination. Its field covers all peripheral vessels: supra-aortic arteries, aorta and its branches, limb arteries. The ultrasound are applied following continuous and pulsed Doppler and real time echography. The two methods may be combined (duplex echography). The investigations are performed first at rest, but assessments under strain are often necessary. The cardiac examination has been enriched by modern methods: thallium scintigraphy under dipyridamole is specially useful in order to measure the coronary reserve. Angiographic images are still a must for most of the aggressive therapeutic decisions. The modern techniques are more flexible using digitalization and a suitable investigation is chosen in function of each individual condition.