Distal Femoral Vein Research Articles

352: RARE PRESENTATION OF CATASTROPHIC ANTIPHOSPHOLIPID SYNDROME IN A TWENTY-SEVEN-YEAR-OLD MAN

Introduction: Antiphospholipid syndrome (APS) is an autoimmune condition manifested by arterial and venous thrombosis, fetal loss, cardiac valvular damage, neurological white matter changes and renal dysfunction. APS is uncommon, with an incidence of 1-2/100,000; close to 80% are in women. We present a rare case of newly diagnosed APS in a 27 year old male. Description: A 27-year-old Hispanic male with no past medical history presented with a chief complaint of difficulty walking. Five weeks prior to admission he began to experience dry eyes and blurred vision, subjective fevers, night sweats, unintentional 20lbs weight loss, and progressive joint pain with inability to ambulate. Vital signs in the emergency room pertinent for temperature 38.5 ℃, blood pressure 126/81 mmHg, tachycardia 108 BPM, SpO2 100% on room air. Physical exam demonstrated tenderness to palpation of lower extremities. Laboratory analysis showed 2.2 x 103/uL white blood cells, hemoglobin 11.4 G/DL, and thrombocytopenia 144 x 103 /uL. Liver enzymes were elevated: ALT 58 U/L, AST 59 U/L. Creatinine was normal at 0.81 mg/dL, however the patient was noted to have an elevated erythrocyte sedimentation rate, 95 MM/HR, and C-reactive protein 47.7. Duplex ultrasound of the lower extremities bilaterally depicted diffuse deep venous thrombosis of right deep veins including the proximal femoral, popliteal, mid and distal femoral vein, and left distal femoral and popliteal vein, with mild residual flow. Given the concern for catastrophic antiphospholipid syndrome, the patient was started on full dose anticoagulation with intravenous heparin, high dose intravenous methylprednisolone, and plasmapheresis. Antinuclear antibody and rheumatoid factor were positive, and the anti-DNA DS antibody grossly elevated at 108 IU/mL. Discussion: Catastrophic Antiphospholipid Syndrome (CAPS) is a rare presentation of APS with mortality as high as 37%, requiring critical care monitoring given the high risk of decompensation. It is characterized by multiorgan dysfunction and thrombosis. A high index of clinical suspicion is essential to initiate prompt treatment. Our patient recovered well after plasmapheresis and was discharged home on apixaban.

CATHETER-DIRECTED THROMBECTOMY OF A SADDLE PULMONARY EMBOLUS

CATHETER-DIRECTED THROMBECTOMY OF A SADDLE PULMONARY EMBOLUS

Case Study of a Rare Incidence of a Leiomyosarcoma Mass Occluding the Distal Femoral Vein

This is a case study of a 47-year-old Caucasian male whose chief concern was left lower leg swelling for 1 month. A unilateral lower extremity venous duplex examination was performed. The results concluded that the distal femoral vein was occluded to the distal popliteal vein. Incidentally, a hypoechoic region in the distal thigh near the distal femoral artery was noted by the technologist. The patient was placed on anticoagulation and was told to return for further examination if there was no relief. Three months later, the patient continued to experience lower left leg swelling and returned for another sonogram. The hypoechoic region was seen again in the distal thigh and remained occluded. A computed tomographic arterial (CT-A) and magnetic resonance imaging (MRI) were ordered for further investigation of the hypoechoic area. The CT-A and the MRI revealed the presence of a mass in the distal thigh. The mass was biopsied and diagnosed as a leiomyosarcoma, grade 1. The mass caused the compression and occlusion of the distal femoral vein. The mass was removed, along with a portion of the distal femoral artery due to involvement of the artery within the mass. The artery was repaired with a graft.

Venous Myxoma of the Distal Femoral Vein: A Rare Case of Leg Pain and Swelling

Background: Myxoma is a rare tumor most frequently discovered in cardiac locations. The present report describes a rare case of extracardiac origin in the femoral vein, initially presenting as leg pain and swelling. Case Presentation: A 40-year-old woman was admitted to our regional hospital with unilateral left leg swelling and pain. She underwent a Duplex scan and CT scan, which revealed a 21 x 25 mm diameter mass in contact with the distal femoral vein, initially diagnosed as a thrombosed sacciform aneurysm. The patient underwent surgical excision of a bulging mass in the vein wall, which was directly closed by running suture. The anatomopathological report concluded with a myxoma. One-year follow-up showed a patent vein without evidence of recurrence of the tumor. Conclusion: Although very rare, peripheral venous myxoma may manifest with common symptoms as leg pain and swelling. Current vascular imaging and complete surgical excision should be performed without delay to allow a precise diagnosis and prevent further complications.

AIUM Practice Parameter for the Performance of Point-of-Care Ultrasound Examinations.

AIUM Practice Parameter for the Performance of Point-of-Care Ultrasound Examinations.

Initial Results of a Clinical Feasibility Study for Endovenous Deep Venous Valve Formation to Treat Chronic Venous Insufficiency

Chronic venous insufficiency (CVI), due to superficial and deep venous reflux (DVR) and venous obstruction, is widespread and associated with significant morbidity. DVR correlates with increased symptoms. Historically, therapeutic approaches to DVR involved difficult and morbid surgical procedures or unsuccessful attempts to implant valves. The study objective was to assess the safety and effectiveness of endovenous formation of autogenous deep vein valves in patients with DVR and significant associated symptoms. The study is ongoing, and results are presented for the first 10 treated patients. Patients with DVR and correlating symptoms of CVI (Clinical, Etiology, Anatomy, and Pathophysiology [CEAP] class C4-C6) were treated with an endovenous autogenous valve formation system in four centers in New Zealand and Australia. Patients with outflow obstruction were excluded. Retrograde percutaneous access was obtained through the common femoral vein, and contrast venography and intravascular ultrasound were used to assess reflux and to identify potential treatment sites. If the patient was deemed eligible, the 16F study device was introduced and used to form monocuspid valves in femoropopliteal vein segments spanning 7 to 11 mm in diameter. Intravascular ultrasound and venography were used to assess valve functionality. Postprocedurally, patients were prescribed 7 days of low-molecular-weight heparin injections, followed by 6 months of anticoagulation. Follow-up included duplex ultrasound scan, physical examination, and questionnaires. Deep venous thrombosis (DVT) was defined as a treated vein found to be noncompressible with visible echogenic thrombus or dilated with decreased flow by ultrasound. Mural thrombus was a deposition that did not fit the DVT criteria. The patients were clinical class C4 (n = 3), C5 (n = 2), and C6 (n = 5) and of both primary (n = 8) and secondary (n = 2) etiology. One or more monocuspid valves were successfully formed in 9 of 10 patients. One valve formation was completed in four patients, two formations in four patients, and three formations in one patient; the anatomy did not accommodate successful valve formation in one patient. Follow-up ranged from 30 to 210 days with a median of 30 days. During this time, no occlusive DVTs were reported, and adverse events related to the device or procedure included access site-related events (n = 7) and mural thrombus (n = 3). All mural thrombi resolved by 90 days. At 30 days, there was a median change in reflux time (seconds) in the proximal femoral vein of 0.3 (−1.9 to 4.3), in the distal femoral vein of 0.4 (−1.4 to 5.6), and in the mid popliteal vein of 0.2 (−3.3 to 6.7). Seven of 10 patients had a ≥4-point improvement in the Venous Clinical Severity Score. Endovenous valve formation in the deep venous system is feasible. Initial experience suggests that it may be safe and effective for treatment of CVI.

Can emergency physicians perform extended compression ultrasound for the diagnosis of lower extremity deep vein thrombosis?

Current point-of-care ultrasound protocols in the evaluation of lower extremity deep vein thrombosis (DVT) can miss isolated femoral vein clots. Extended compression ultrasound (ECUS) includes evaluation of the femoral vein from the femoral vein/deep femoral vein bifurcation to the adductor canal. Our objective is to determine if emergency physicians (EPs) can learn ECUS for lower extremity DVT evaluation after a focused training session. Prospective study at an urban academic center. Participants with varied ultrasound experience received instruction in ECUS prior to evaluation. Two live models with varied levels of difficult sonographic anatomy were intentionally chosen for the evaluation. Each participant scanned both models. Pre- and post-study surveys were completed. A total of 96 ultrasound examinations were performed by 48 participants (11 attendings and 37 residents). Participants' assessment scores averaged 95.8% (95% CI 93.3%-98.3%) on the easier anatomy live model and averaged 92.3% (95% CI 88.4%-96.2%) on the difficult anatomy model. There were no statistically significant differences between attendings and residents. On the model with easier anatomy, all but 1 participant identified and compressed the proximal femoral vein successfully, and all participants identified and compressed the mid and distal femoral vein. With the difficult anatomy, 97.9% (95% CI 93.8%-102%) identified and compressed the proximal femoral vein, whereas 93.8% (95% CI 86.9%-100.6%) identified and compressed the mid femoral vein, and 91.7% (95% CI 83.9%-99.5%) identified and compressed the distal femoral vein. EPs at our institution were able to perform ECUS with good reproducibility after a focused training session.

Experience of central venous catheterization via the distal femoral vein using ultrasound guidance

Experience of central venous catheterization via the distal femoral vein using ultrasound guidance

Definition of venous reflux in lower-extremity veins.

This prospective study was designed to determine the upper limits of normal for duration and maximum velocity of retrograde flow (RF) in lower extremity veins. Eighty limbs in 40 healthy subjects and 60 limbs in 45 patients with chronic venous disease were examined with duplex scanning in the standing and supine positions. Each limb was assessed for reflux at 16 venous sites, including the common femoral, deep femoral, and proximal and distal femoral veins; proximal and distal popliteal veins; gastrocnemial vein; anterior and posterior tibial veins; peroneal vein; greater saphenous vein, at the saphenofemoral junction, thigh, upper calf, and lower calf; and lesser saphenous vein, at the saphenopopliteal junction and mid-calf. Perforator veins along the course of these veins were also assessed. In the healthy volunteers, 1553 vein segments were assessed, including 480 superficial vein segments, 800 deep vein segments, and 273 perforator vein segments; and in the patients, 1272 vein segments were assessed, including 360 superficial vein segments, 600 deep vein segments, and 312 perforator vein segments. Detection and measurement of reflux were performed at duplex scanning. Standard pneumatic cuff compression pressure was used to elicit reflux. Duration of RF and peak vein velocity were measured immediately after release of compression. Duration of RF in the superficial veins ranged from 0 to 2400 ms (mean, 210 ms), and was less than 500 ms in 96.7% of these veins. In the perforator veins, regardless of location, outward flow ranged from 0 to 760 ms (mean, 170 ms), and was less than 350 ms in 97% of these veins. In the deep veins, RF ranged from 0 to 2600 ms. Mean RF in the deep femoral veins and calf veins was 190 ms, and was less than 500 ms in 97.6% of these veins. In the femoropopliteal veins, mean RF was 390 ms, and ranged from 510 to 2600 ms in 21 of 400 segments; however, RF was less than 990 ms in 99% of these veins. Duration of RF was significantly longer in all three veins systems in patients (P <.0001 for all comparisons). With a cutoff value of more than 1000 ms rather than more than 500 ms, prevalence of abnormal RF in the femoropopliteal veins was significantly reduced, from 29% to 18% (P =.002). Thirty-seven vein segments (2.4%) had RF greater than 500 ms in the supine position, compared with less than 500 ms in 22 of these vein segments (59%) in the standing position. Of the 48 vein segments (3.1%) with RF greater than 500 ms in the standing position, RF was less than 500 ms in 6 of these vein segments (13%) in the supine position. Similar observations were noted in patient veins. There was no association between RF and peak vein velocity. Peak vein velocity had no significance in determining reflux. The cutoff value for reflux in the superficial and deep calf veins is greater than 500 ms. However, the reflux cutoff value for the femoropopliteal veins should be greater than 1000 ms. Outward flow in the perforating veins should be considered abnormal at greater than 350 ms. Reflux testing should be performed with the patient standing.

Thrombolysis for experimental deep venous thrombosis maintains valvular competence and vasoreactivity

Purpose: Thrombolysis protects the structural and functional integrity of vein wall in an experimental model of acute deep venous thrombosis (DVT) immediately after treatment, but late sequelae have not been studied. We designed experiments to compare the effects of thrombolysis and surgical thrombectomy at 4 weeks after the treatment of DVT.Methods: DVT was produced bilaterally in male mongrel dogs by proximal and distal femoral vein ligation. Five dogs underwent sham operation. After 48 hours, the ligatures were removed, and the thrombosis was treated with either Fogarty balloon catheter thrombectomy (shear force, 60 g; n = 6) or catheter-directed urokinase infusion (4000 U/min for 90 minutes; n = 6). At 4 weeks, patency and valvular competence were determined by duplex ultrasound scanning. Thrombogenicity was studied by the measurement of radiolabeled fibrin and platelet deposition. Veins were explanted and prepared for histologic examination, scanning electron microscopy, and functional studies in organ chambers.Results: All veins were patent at 1 month. Recanalized thrombus was observed histologically in four (66%) thrombectomized veins, one (17%) thrombolyzed vein, and none of the sham-operated veins (P = .04). Scanning electron microscopy demonstrated similar luminal endothelial cell loss (11%–25%) in all three groups. Platelet and fibrin depositions were not different among groups. Valvular incompetence (reflux duration, >0.5 sec) did not differ significantly in the groups (thrombectomized veins, 2 of 12 (17%); thrombolyzed veins, 0 of 12 (0%); P = NS). In organ chamber studies, endothelium-dependent relaxations to calcium ionophore, but not adenosine diphosphate, were inhibited by an antagonist of nitric oxide production after thrombectomy (P < .05, thrombectomy vs sham- and thrombolysis-treated veins). All veins relaxed to exogenous nitric oxide.Conclusion: Both thrombectomy and thrombolysis restored patency and achieved similar valvular competence. Surgical thrombectomy, however, resulted in more residual thrombus and contributed to changes in endothelium-mediated relaxations at 4 weeks. Thrombolysis maintained both structural integrity and endothelial function.

Venous duplex scanning of the leg: range, variability and reproducibility

Despite the many studies on venous haemodynamics using duplex, only a few evaluated the normal values, variability and reproducibility. Therefore, the range and variability of venous diameter, compressibility, flow and reflux were measured. To obtain normal values, 42 healthy individuals (42 limbs, 714 vein segments) with no history of venous disease were scanned by duplex. To determine the reproducibility the intra-observer variability was measured in 11 healthy individuals (187 vein segments) and the inter-observer variability in 15 healthy individuals (255 vein segments) and 13 patients (169 vein segments) previously diagnosed with deep venous thrombosis. Of the 714 normal vein segments, 708 (99%) were traceable, including the crural veins. Of the traceable vein segments, 675 (95%) were compressible and in 696 (98%) flow was present. Of the 42 common femoral vein segments, in 25 (60%) the reflux duration exceeded 1.0 s, but in the other proximal vein segments the reflux duration was less than 1.0 s (95% confidence interval 3.0-10.0). With the exception of the distal long saphenous vein, in the distal vein segments the reflux duration was less than 0.5 s (95% confidence interval 3.5-8.2). The coefficient of variation of the diameter measurements ranged from 14 to 50% and that of the reflux measurements from 28 to 60%. The kappa-coefficient of the inter-observer variability in the classification of compressibility measurements in the patients was 0. 77 and that of the reflux measurements was 0.86. This study shows that almost all veins were compressible in healthy individuals, except the distal femoral veins. In healthy individuals the duration of reflux of the proximal veins was less than 1.0 s and in the distal veins it was less than 0.5 s. The inter-observer variability of the reflux and compressibility measurements in the patients was good.

Arterialization of the venous system in a rat lower limb model

Creation of alternative vascular conduits has been one of the most challenging subjects in the history of vascular surgery. In the past, afferent arteriovenous fistulas have been used by vascular surgeons to rescue ischaemic extremities. We have undertaken a comprehensive investigation to characterize arterialization of the venous system at different levels of the rat lower limb. In Group 1 ( n = 28), we performed an end-to-end anastomosis between the proximal saphenous artery and the distal saphenous vein (Superficial venous system), and ligated all other branches of the femoral artery. In Group 2 ( n = 28), we performed an end-to-end anastomosis between the proximal saphenous artery and the distal femoral vein (Deep venous system). In Group 3 ( n = 24), the control group, the femoral artery was ligated proximal to its trifurcation into the saphenous, epigastric, and distal femoral vessels. Group 4 ( n = 10), the normal group, underwent no surgery. Animals were sacrificed at the first, third, and eighth postoperative weeks. Arteriographic, India ink injection, latex injection, and histological studies were performed on all groups. Successful arterialization of veins, significant neovascularization, and less ischaemic injury of muscles were noted in the arterialized vein groups (Groups 1 and 2) when compared with the ligated group (Group 3). This model appears to depict successfully arterialization of the lower limb venous system in a small animal model.

Lysis block treatment: a new form of local thrombolysis.

Lysis block treatment (LBT) is a new form of fibrinolytic therapy for deep vein thrombosis and arterial occlusion in the distal parts of the limbs. Strictly local lysis was achieved by placing a cuff around the thigh or the upper arm, inflating the cuff to a pressure of 500 mmHg ("Bier's blockade"), and giving heparin and tissue plasminogen activator (rt-PA) by intravenous injection into the dorsal pedis or antecubital veins. Occlusion lasted for one hour. This new technique was demonstrated in 22 patients. Six patients presented with popliteal vein thromboses and 1 patient with a distal femoral vein thrombosis. In addition, 15 arterial occlusions were treated comprising 3 calf, 6 popliteal, 3 distal femoral, and 2 digital sites and 1 brachial site. Five of 7 venous and 9 of 15 arterial occlusions were partially or totally removed. The activated partial thromboplastin time remained nearly unchanged during LBT and only a limited and short-term lengthening was recorded after restoration of blood flow. This was of importance for patients with bleeding tendencies, which are normally a contraindication for systemic lysis. LBT may therefore be considered as a useful alternative to systemic fibrinolytic treatment.

The effect of venous flow alterations upon patency of rat femoral vein anastomoses.

The rat femoral vein has become a standard model for laboratory training in microvascular anastomotic technique as well as for research investigations into factors affecting venous patency. This study examined the short-term patency (1 and 7 days) of rat vein anastomoses. The influences upon patency of epigastric flap creation and distal femoral vessel ligation (epigastric flow only) were explored. In a separate experiment, blood flow from the femoral vein was determined through catheter collection of venous efflux; the influences of island epigastric flap creation and distal femoral ligation on flow rates were explored. It was found that 82% of basic femoral vein anastomoses were patent at one day, while 100% of anastomoses associated with an epigastric flap and ligated/transected distal femoral vessel circulation (creating a low-tension anastomosis) were patent (P less than 0.01). With distal femoral vessel ligation and no transection (normal tension at the repair), anastomoses were patent in 90% of the veins when an epigastric flap was also raised, and in 60% when a flap was not created. When a flap was raised without disturbing the distal femoral circulation, vein patency was 75% at one day. When the vein anastomosis was performed with distal femoral vein ligation, the patency rate was 50%. All veins patent at 1 day were also patent at 7 days post-op; 96% of veins clotted at 1 day were found to be patent at 7 days. The venous efflux was not found to vary significantly when an epigastric flap was raised.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental acute and chronic vascular access through the femoral vessels: hemodynamic study in dogs.

In a side-to-side fistula between femoral artery and vein, an external "shunt" was created that simultaneously connected the distal femoral vein and the proximal femoral vein in 14 normal dogs with weight ranging from 14 to 28 kg. Blood flow and pressure alterations of different sites of this experimental model of vascular access were studied. The results showed that the degree of blood flow on these two vascular communications depends on the structural integrity of the femoral artery with adequate blood flow and blood pressure. Also, the correct connection of external shunt with the fistula is of equal importance. It is suggested that the blood pressure as well as the blood flow rate of these two vascular communications were adequate to allow performance of acute and chronic hemodialysis.

SAFETY AND EFFICACY OF WARFARIN STARTED EARLY AFTER SUBMASSIVE VENOUS THROMBOSIS OR PULMONARY EMBOLISM

Two anticoagulant regimens, similar except for the timing of warfarin therapy, were compared in patients with clinically submassive venous thromboembolism (VTE). Warfarin was begun after 7 days of continuous intravenous heparin infusion in group L (127 patients) or within 3 days (average 1 day) of starting heparin in group S (139 patients), with similar outcomes. The frequency of symptomatic VTE recurrence during the hospital stay was 4.7% in group L and 3.6% in group S, and that of symptomless new perfusion defects 8.5% in group L and 3.9% in group S. On routine iodine-125-fibrinogen leg scanning of patients presenting with distal thrombosis (in the calf, popliteal, or distal femoral veins) 3.6% of group S but no group L patients had symptomless proximal extension. The incidence of bleeding was similar with both regimens. Outpatient follow-up showed no excess recurrent VTE in either treatment group. Early warfarin treatment significantly shortened hospital stay by an average of 3.9 days (30%) in patients admitted solely because of VTE.

Increased effective vascular compliance and venous pooling of intravascular volume during sustained venodilation in conscious dogs.

The hemodynamic effects of the long-acting antianginal drug molsidomine were studied in 8 chronically instrumented conscious dogs by measuring the partition of the intravascular volume and the effective compliance of the total vascular bed. The blood volume of the resting dogs was varied by +/- 4 ml/kg in a cycle of blood infusion, withdrawal and reinfusion within 12 minutes. Relating the observed alterations in mean right atrial pressure to the induced changes in intravascular volume, an effective compliance of 2.9 +/- 0.4 ml. mm Hg-1 . kg -1 (mean +/- SD) was found. Heart rate, total peripheral vascular resistance and the local capacity of the distal femoral vein did not change significantly during the cycle of volume alterations. Following 0.1 mg/kg molsidomine i.v., mean right atrial pressure was lowered by 1.6 mm Hg and mean left atrial pressure by 3.4 mm Hg; the effective compliance was elevated to 4.7 +/- 0.6 ml . mm Hg-1. kg -1 (p less than 0.001), and the central blood volume was lowered from 17.8 +/- 3.1 to 14.8 +/0 3.3 ml/kg (p less than 0.01), while the total blood volume remained constant. The decline in stroke volume and the reflexly induced increase in heart rate correlated with the control heart rate. Mean arterial pressure declined from 101 +/- 7 to 91 +/- 14 mm Hg (p less than 0.05) and total peripheral vascular resistance remained unaffected. It is concluded that molsidomine exerts exerts its hypotensive effect by dilation within the vascular low-pressure system and that this dilation can be described quantitatively in conscious animals by the analysis of the total effective vascular compliance.

Fistula size and hemodynamic events within and about canine femoral arteriovenous fistulas

The effects of diameters of canine femoral arteriovenous fistulas upon regional and central hemodynamics were determined to correlate fistula size with fistula flow, as well as changes in cardiac output, “reversal” of distal arterial flow, and distal venous hypertension. Flows were measured electromagnetically. Cardiac output was determined with thermodilution techniques. Fistula size, ranging from 2 to 16 mm. in diameter, was represented by four dogs in each of four groups. Unstimulated femoral arterial blood flow was 4.76 ± 0.39 (X ± S.E.) ml. min. -1 Kg. -1 ; aortic pressure (AP) was 152 ± 4 mm. Hg; certral venous pressure (CVP) was 4 ± 1 mm. Hg. Pulse (P) was 147 ± 5 beats min. -1 . Cardiac output (CO) increased progressively in response to the three largest fistulas. The 4 mm. fistula increased CO by 19.6 ± 4.5 ml. min. -1 Kg. -1 (p < 0.025). The largest fistula (16 mm.) increased CO by 44.5 ± 2.3 ml. min. -1 Kg. -1 (p < 0.001). Femoral arterial flow, proximal to the fistula, was increased fivefold by the 4 mm. fistula and further increased by a factor of 10 with the 8 mm. fistula; whereupon, flow did not further increase with the largest fistula. Changes in fistula flow (FF) were indistinguishable from changes in PAF. Distal femoral arterial flow (DAF) underwent comparable decreases in response to the three smallest fistulas, but antegrade flow was maintained. The largest fistula caused retrograde flow in the direction of the fistula (4.6 ± 0.3 ml. min. -1 Kg. -1 , p < 0.001). AP was decreased only by the largest fistula (-26 ± 3 mm. Hg, p < 0.001). CVP was unchanged by any of the four fistulas; however, pressure in the distal femoral vein was increased by the largest fistula to a value of 14 ± 1 mm. Hg (p < 0.001). There appears to be a direct correlation between fistula size and cardiac output, but there is a limit to flow through an arteriovenous fistula, as well as to that through the proximal artery contributing to the fistula. Venous hypertension, distal to the fistula, correlates the size of the fistula and is maximized by a fistula whose size exceeds the transverse diameter of the contributing vein. The larger the fistula, the greater the diminution in distal femoral artery flow and pressure.

Determination of lower leg blood flow in man by thermodilution.

A thermodilution method for measuring distal femoral vein flow in man is presented. The catheter is introduced percutaneously in central direction into the popliteal vein. Tests for accuracy in vitro (r = 0.999, range of true flow 63–2600 ml/min) and in dog experiments (r = 0.994, range of electromagnetic flow measurements 110–780 ml/min) are presented and discussed in relation to the anatomical (dissections on corpses) and functional conditions in the popliteal/distal femoral vein of man. A group of normal persons [7] and of patients suffering from ischaemic lower limb disease [17] were studied at rest and during exercise on an ergometer in supine and sitting positions. In all but two, reliable measurements were obtained. In the normals, a mean resting flow of 114 ml/min (range 82–140 ml/min) was found. The individual coefficient of correlation between load and flow measurements in the normals varied from 0.80 to 0.94 during stepwise increasing load exercise. No serious complications occurred. The method...