Patency and Clinical Outcome After Stent Placement for Chronic Obstruction of the Inferior Vena Cava.

OBJECTIVE/BACKGROUND: The objective was to assess the technical success, patency, and clinical outcome after stent placement for chronic obstruction of the inferior vena cava (IVC). METHODS: A retrospective analysis was carried out of patients with chronic IVC obstruction verified with computed tomography and/or magnetic resonance venography, accepted for stent placement at the Norwegian National Unit for Reconstructive Deep Venous Surgery from March 2010 to September 2015. Clinical status was categorized according to the CEAP classification and symptom severity was assessed using venous clinical severity score (VCSS). Stent patency was evaluated by colour duplex ultrasound. Large -diameter Wallstents were placed in the IVC and concurrent iliac and femoral obstructions via right internal jugular and femoral vein access. Sixteen patients presented with symptoms of chronic venous disease. Four patients had symptoms assumed to be related to a reduced cardiac preload. Twelve patients had IVC occlusion and eight had stenosis. Median follow-up was 25 months (range 3-70 months). RESULTS: Stent placement in the IVC was successful in 19 of 20 patients. Primary patency after 24 months was 67% and secondary patency 83%. Fifteen of 19 patients had open stents at final follow-up. Re-interventions were performed in four patients and included catheter directed thrombolysis in all and adjunctive stenting in three. Thirteen of 19 patients (68%) reported a sustained and significant clinical improvement. Mean VCSS improved from 8.5 (range 3-25) at baseline to 7 (range 2-23) at final follow-up (p = .007). There were no peri-procedural or long-term complications. CONCLUSION: The endovascular approach with stent placement for chronic IVC obstruction is a safe treatment option that should be offered to patients who otherwise have little opportunity for sustained clinical improvement.

Haemodynamics and catheter-based imaging in the diagnosis of venous disease. An interventional targeted approach.

The investigation of patients with severe chronic venous insufficiency (CVI, C3-C6) represents a challenge that requires the understanding of venous pathophysiology and a multidisciplinary approach; it should be aimed to assess valve function, evaluate the haemodynamic significance of obstruction and assess the function of the vein-muscle pump. Combining haemodynamic tests and imaging techniques best accomplish the investigation of these three aspects of the pathophysiology in CVI. The information obtained from ambulatory venous pressure and color duplex ultrasound is accurate when assessing reflux in the different segments of the different venous systems. The valve anatomic location and dynamic picture is supplied by descending phlebography. In case of venous obstruction, the haemodynamic tests lack accuracy and sensitivity. Therefore, imaging catheter techniques have to fill-in to depict vein morphology as well as inflow/outflow characteristics. The participation of several specialties in the investigation of these patients widens the treatment possibilities by identifying those who may benefit from advanced surgical and/or endovascular procedures. This interventional-targeted approach should be a centralized function.

Stenting for chronic post-thrombotic vena cava and iliofemoral venous occlusions: mid-term patency and clinical outcome.

OBJECTIVES: The aim of this study was to determine the mid-term patency and the clinical outcome after stenting of chronic occluded caval and iliofemoral venous segments. DESIGN: Observational study. MATERIAL/METHODS: During the period 2000 and 2009, 2400 patients with chronic venous insufficiency (CVI) were evaluated, and 34 with chronic venous occlusions after deep venous thrombosis (DVT) were selected for endovascular treatment. The median age was 41 (range 15-63) years, and 19 were female. The following investigations were undertaken: colour duplex ultrasound (CDU), ascending venography (AV), venous occlusion plethysmography (VOP), venous pressure gradient (VPG) and CT venography or trans-femoral/popliteal venography. The major symptoms were venous claudication, oedema, pain and ulcer. All patients were treated by stenting occluded segments. Self-expanding stents were deployed in 22 iliofemoral, nine iliac and one caval-iliac-femoral. Twenty-one procedures required stenting across the inguinal ligament. RESULTS: Primary recanalisation was accomplished in 32/34 (94%). The median follow-up was 33 months (1-96) with clinical examination, CDU and VOP. Two-year primary patency was 14/21 (67%), primary-assisted patency 16/21(76%), and secondary patency was 19/21 (90%). Venous claudication and oedema resolved in those successfully recanalised. Four of the seven ulcers healed. CONCLUSION: Stenting to treat venous claudication, oedema and recurrent venous ulcer caused by post-thrombotic chronic venous occlusions has positive clinical outcome and good mid-term patency.

Catheter-directed thrombolysis vs. anticoagulant therapy alone in deep vein thrombosis: results of an open randomized, controlled trial reporting on short-term patency.

BACKGROUND: Approximately one in four patients with acute proximal deep vein thrombosis (DVT) given anticoagulation and compression therapy develop post-thrombotic syndrome (PTS). Accelerated removal of thrombus by thrombolytic agents may increase patency and prevent PTS. OBJECTIVES: To assess short-term efficacy of additional catheter-directed thrombolysis (CDT) compared with standard treatment alone. PATIENTS AND METHODS: Open, multicenter, randomized, controlled trial. Patients (18-75 years) with iliofemoral DVT and symptoms < 21 days were randomized to receive additional CDT or standard treatment alone. After 6 months, iliofemoral patency was investigated using duplex ultrasound and air-plethysmography assessed by an investigator blinded to previous treatment. RESULTS: One hundred and three patients (64 men, mean age 52 years) were allocated additional CDT (n = 50) or standard treatment alone (n = 53). After CDT, grade III (complete) lysis was achieved in 24 and grade II (50%-90%) lysis in 20 patients. One patient suffered major bleeding and two had clinically relevant bleeding related to the CDT procedure. After 6 months, iliofemoral patency was found in 32 (64.0%) in the CDT group vs. 19 (35.8%) controls, corresponding to an absolute risk reduction (RR) of 28.2% (95% CI: 9.7%-46.7%; P = 0.004). Venous obstruction was found in 10 (20.0%) in the CDT group vs. 26 (49.1%) controls; absolute RR 29.1% (95% CI: 20.0%-38.0%; P = 0.004). Femoral venous insufficiency did not differ between the two groups. CONCLUSIONS: After 6 months, additional CDT increased iliofemoral patency from 36% to 64%. The ongoing long-term follow-up of this study will document whether patency is related to improved functional outcome.

Noninvasive coronary angiography with 64-channel multidetector computed tomography in patients with acute coronary syndrome.

BACKGROUND: Advances in computer tomography (CT) imaging technology in recent years have facilitated the possibility of noninvasive coronary angiography. PURPOSE: To compare the diagnostic accuracy of 64-channel multidetector computed tomography (MDCT) with conventional invasive coronary angiography (ICA) for the detection of significant coronary stenosis in patients with acute coronary syndrome (ACS). MATERIAL AND METHODS: MDCT was performed in 60 patients classified with non-ST-elevation infarction (NSTEMI) or unstable angina and scheduled for ICA within 3 days. The diagnostic accuracy of MDCT was evaluated using quantitative coronary angiography (QCA) as the gold standard. RESULTS: 48 out of 60 patients had interpretable scans by both MDCT and ICA. On a segment-based analysis, 488 out of 665 segments with a diameter of > or =1.5 mm, as defined by QCA, were interpretable by MDCT. Sensitivity was 78%, specificity 87%, positive predictive value 47%, and negative predictive value 97% in detecting and excluding significant coronary stenosis, as defined with MDCT. On a per patient-based analysis, sensitivity was 89%, specificity 50%, positive predictive value 84%, and negative predictive value 60%. CONCLUSION: Limited diagnostic accuracy restricts the usefulness of coronary MDCT in patient groups with a high pretest probability of disease, such as in acute coronary syndrome.

Treatment with autologous bone marrow mononuclear cells in patients with critical lower limb ischaemia. A pilot study.

BACKGROUND AND AIMS: Treatment with autologous, bone marrow mononuclear stem cells has shown effects in patients with chronic limb ischaemia in one randomized clinical study. The aim of the study was to test the potential effect of stem cell treatment in a strict defined group of patients with stable critical limb ischaemia (CLI). DESIGN: A prospective, combined-centre pilot study. MATERIAL: Eight patients with CLI of the lower extremities, and without any other treatment options. METHODS: Bone marrow cells were harvested from the patient's iliac crest and, after separation, injected into the calf muscles of the affected leg. Outcome was evaluated by digital subtraction angiography (DSA), visual analogue scale (VAS) and several non-invasive circulatory physiological tests. RESULTS: There were no complications from the procedures. Two patients were amputated two months after cell injection. Five patients reported pain relief after four months. Five patients could be evaluated at eight months. According to VAS and physiological tests, they were all either stable or showed improvement. CONCLUSION: This method seems to be a safe option for treating patients with CLI. Inclusion of patients took a long time, mainly because many patients with CLI are offered endovascular treatment in our institution. While symptomatic improvement was found in individual patients, larger trials are required to investigate efficacy. This will probably require multi-centre participation.

Beneficial effects of 1-year optimal medical treatment with and without additional PTA on inflammatory markers of atherosclerosis in patients with PAD. Results from the Oslo Balloon Angioplasty versus Conservative Treatment (OBACT) study.

The influence of optimal medical treatment (OMT) with or without additional percutaneous transluminal angioplasty (PTA) on vascular inflammation in peripheral arterial occlusive disease (PAD) patients was investigated. Patients with intermittent claudication (IC) and angiographically verified PAD were randomized to OMT (n = 28) or OMT + PTA (n = 28) and followed for 12 months. Ankle-brachial index (ABI), treadmill walking distances (WD), visual analogue scale (VAS), and blood sampling for the determination of selected soluble biomarkers were undertaken at baseline and after 3 and 12 months. After both 3 and 12 months, ABI, WD and VAS were highly significantly improved in favour of OMT + PTA (p < 0.05 for all). Significant improvements were recorded in both groups in serum lipids (p < 0.01 for all), except for triglycerides, and in the inflammatory markers P-selectin, interleukin-6, interleukin-10, monocyte chemoattractant protein-1 and fibrinogen (p < 0.05 for all). There were, however, no differences in the changes from baseline between the groups in any variable. Intervention with OMT alone or in combination with PTA did not differ with regard to the effects on serum lipids and markers of inflammation in our population of PAD patients. The combined treatment was, however, better for the treadmill walking distance.

The Oslo balloon angioplasty versus conservative treatment study (OBACT)--the 2-years results of a single centre, prospective, randomised study in patients with intermittent claudication.

OBJECTIVES: To compare the effect of optimal medical treatment only (OMT) with OMT combined with percutaneous transluminal angioplasty (OMT+PTA) in patients with intermittent claudication (IC). DESIGN: A single centre prospective, randomised study. Quality of life (QoL) was the primary outcome measure. Secondary measures were ankle-brachial-index (ABI), treadmill walking distances and mortality. METHODS: From a total of 434 patients considered for inclusion into the trial, only 56 patients with disabling IC fulfilled the inclusion criteria. The patients were randomised into treatment groups consisting of 28 patients each and followed for 2 years. ABI and treadmill walking distances were measured in addition to the visual analogue scale (VAS) for pain evaluation, and QoL assessment using the Short Form (SF-36 and Claudication Scale (CLAU-S). RESULTS: The demographic data in the 2 groups were almost identical. After 2 years of follow-up the ABI, the treadmill walking distances and the VAS were significant improved in the group treated with OMT+PTA, compared to the group treated with OMT only (p<0.01 for all). Furthermore, some variables from the QoL assessment also showed a significant improvement in favour of the OMT+PTA group (p<0.05 for all). CONCLUSION: The advantage of conducting a single centre study and adhering to very strict inclusion criteria was illustrated by the homogenous demographic data of the two groups. This partly outweighed the disadvantage of having included a relatively small number of patients. Early intervention with PTA in addition to OMT seems to have a generally more positive effect compared to OMT only, on haemodynamic, functional as well as QoL aspects during the first 2 years in patients with IC.

Markers of vascular inflammation are associated with the extent of atherosclerosis assessed as angiographic score and treadmill walking distances in patients with peripheral arterial occlusive disease.

The importance of inflammation in atherosclerosis is well established in cardiovascular disease. However, limited data exist on the relationship between vascular inflammation and the severity of peripheral arterial occlusive disease (PAD). We investigated the relationship between biochemical markers of vascular inflammation and the diagnostic measures of PAD: ankle-brachial pressure index (ABI), maximum treadmill walking distance and angiographic score. In 127 patients (mean age 66 years; 64% males) with angiographically verified PAD, fasting blood samples were drawn for determination of selected soluble cell adhesion molecules, cytokines and chemokines. Tumor necrosis factor-alpha (TNFalpha), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1) and CD40 ligand (CD40L) were all significantly correlated with the angiographic score (p < 0.05 for all). After adjustment for relevant co-variates, MCP-1 and CD40L remained statistically significant (p < 0.01 for both). IL-6 was, independent of other risk factors, inversely correlated with the maximum treadmill walking distance (p < 0.01). Our cross-sectional study in PAD patients showed that the vascular inflammatory markers MCP-1, CD40L and IL-6 were significantly associated with the extent of atherosclerosis, assessed by angiographic score and maximum treadmill walking distance. These findings indicate that vascular inflammation is implicated in PAD, which might be of importance in future diagnosis and treatment of the disease.

Gadolinium-enhanced magnetic resonance angiography, colour duplex and digital subtraction angiography of the lower limb arteries from the aorta to the tibio-peroneal trunk in patients with intermittent claudication.

OBJECTIVES: To evaluate the sensitivity, specificity, positive and negative predictive value of contrast-enhanced (gadolinium) magnetic resonance imaging (CE-MRA) and colour duplex ultrasound (CDU) of lower limb arteries. DESIGN: Prospective, single centre study. MATERIAL AND METHODS: A consecutive series of 58 patients with intermittent claudication (IC) were examined with CE-MRA and CDU from the infrarenal aorta to the tibio-peroneal trunk with digital subtraction angiography (DSA) as reference. The arterial tree was divided into 15 segments, pooled into three regions; suprainguinal, thigh and knee. Sensitivity, specificity, positive and negative predictive values for significant obstructions were calculated. Cohen Kappa statistics was used to establish agreement between the three methods. RESULTS: The sensitivity (specificity in parentheses) for significant obstructions in the suprainguinal region were 96% (94%) for CE-MRA and 91% (96%) for CDU, in the thigh region 92% (95%) for CE-MRA and 76% (99%) for CDU, and in the knee region 93% (96%) for CE-MRA and 33% (98%) for CDU. CDU failed to visualize 10% of suprainguinal, 2% of thigh and 13% of knee-region arterial segments. CONCLUSIONS: Both CE-MRA and CDU are good alternatives to DSA in the suprainguinal- and thigh-region. In the knee region only CE-MRA can be relied upon as an alternative to DSA. Imaging by CDU is not suited to situations were evaluation of runoff vessels is important.

Computed tomography of the urinary tract: optimalization of low-dose stone protocol in a clinical setting.

PURPOSE: To establish whether information would be lost if slice reconstruction thickness was increased from 3 to 5 mm, and whether this altered how difficult it was to interpret the examinations. MATERIAL AND METHODS: Twenty-three consecutive patients referred with suspected or known urinary stones were included. All examinations were performed without intravenous contrast media. The original series, with effective mAs 50, were reconstructed with slice thickness 3 and 5 mm, respectively. All demographic and examination data were removed and the series reviewed in PACS by two independent radiologists. Objective findings, i.e. number and size of stones, signs of obstruction, and evaluation of interpretation difficulty, were registered. RESULTS: Identical findings were registered in 18 of the series of 3 mm (n=23) and 19 of the series of 5 mm (n=23). In two series reconstructed with 3 mm slice thickness and in one series with 5 mm slice thickness, the observers disagreed on the presence of urinary stones. Main reasons for interpretation difficulties were given as "lack of intra-abdominal fat" and "many phleboliths in the pelvic region", but never "disturbing noise". CONCLUSION: To determine the presence and size of urinary stones at low-dose computed tomography, 5 mm reconstruction algorithm seems equal to 3 mm. Patient-related factors influence the interpretation more than image quality.

Subintimal angioplasty in the treatment of patients with intermittent claudication: long term results.

OBJECTIVES: Reporting the long-term results of subintimal angioplasty (SA) in patients with intermittent claudication (IC). DESIGN: A prospective study. PATIENTS: One hundred and sixteen SA procedures were performed in 104 patients, from February 1997 to January 2000. METHODS: This is a prospective study of patients treated for IC with infrainguinal SA. Primary assisted patency rates were calculated, also on intention to treat basis. Univariate and multivariate Cox regression tests were used to assess whether patency was correlated with co-morbidities, run-off or occlusion length. RESULTS: There was no early mortality. Technical success was achieved in 101 cases (87%). Primary assisted patency rates on intention to treat basis (116 cases) at 6, 12, 36 and 60 months were 69, 62, 57 and 54%, respectively. For successfully recanalized patients (101 cases) these respective numbers are 79, 70, 66 and 64%. Length of occlusion, age and male gender were independent risk factors for reocclusion. CONCLUSIONS: The satisfactory results obtained in the present study are probably due to two main factors. First, the three participating radiologist are highly skilled and experienced. Secondly, a conscientious surveillance was adhered to, so that restenoses could be diagnosed and treated early. SA is a relevant alternative to bypass surgery in patients with disabling IC due to long femoro-popliteal occlusions. It is far less traumatic than conventional vascular reconstructions, complications are few and not serious. Very importantly, SA never interfered with later successful vascular surgery. Therefore, we have adopted SA as the primary treatment for patients with IC when medical treatment alone has not been satisfactory.

Outcome after catheter-directed thrombolysis of occluded prosthetic femoropopliteal bypasses. A prospective study.

PURPOSE: To evaluate the outcome after catheter-directed thrombolysis of occluded femoropopliteal prosthetic bypasses with the distal anastomosis above the knee. MATERIAL AND METHODS: Twenty-one patients were included in this prospective study. End-hole catheters, a bolus dose and continuous infusion of recombinant tissue-plasminogen activator (rt-PA) were used, with a median total dose of 10 mg (range 7-20 mg). RESULTS: With an intra-thrombotic position of the catheter, total or subtotal lysis was obtained in 19 of 21 patients (90%). No serious complications occurred. In 9 patients, the stenoses were successfully treated with balloon angioplasty (PTA, n=5), local thrombectomy/extension of bypass (n=3), or with a new bypass (n=1). After a median observation time of 18 months (6-24), 5 patients had open bypass. Re-occlusion occurred in all (6/6) bypasses in which no flow-limiting lesion was discovered, in all (4/4) bypasses treated twice with thrombolysis, as well as in all bypasses in which stenoses had not been adequately treated (3/3). One bypass re-occluded immediately due to poor runoff. CONCLUSION: In the present study, 19/21 infra-inguinal prosthetic bypasses were successfully treated with catheter-directed thrombolysis. However, re-occlusion often took place, especially in bypasses without flow-limiting lesions. If re-occlusion occurs in a bypass in which no stenoses were revealed during the primary thrombolysis procedure, a second catheter-directed thrombolytic treatment does not seem to be warranted. Our results confirm that treatment of flow-limiting lesions is a prerequisite for maintaining patency.

Soluble fibrin species in arterial thrombi.

The aim of this study was to characterize soluble fibrin(ogen) species in human, arterial, in-vivo-formed thrombi, using the immunoblotting technique. Specimens were collected via intra-arterial catheters in six patients scheduled for catheter-directed thrombolysis. Unreduced and reduced samples of the supernatants from the arterial thrombi-derived specimens were electrophoresed on polyacrylamide gels and immunoblotted, using specific mono- and polyclonal anti-fibrin(ogen) antibodies. The reduced samples disclosed substantial amounts of high molecular weight material, consistent with alpha-chain polymers and gammagamma-dimers, as well as lower molecular weight material, such as alpha-, beta- and gamma-chains. No fibrinogen with intact fibrinopeptide A was detectable, and des-AABB fibrin represented a major fibrin derivative in the soluble part of the arterial thrombi. The alpha-chains were C-terminally degraded, most of them distal to position 259. In conclusion, we have demonstrated the presence of cross-linked fibrin derivatives in soluble, arterial thrombus-related material, without signs of fibrinogen-fibrin hybrids. The fibrin derivatives were C-terminally degraded, thus representing X-oligomeric material, most probably originating from plasmin degradation of insoluble thrombus fibrin. The present study supports the hypothesis of a dynamic equilibrium between clotting and lysis in thrombi.

Catheter-directed intra-arterial thrombolysis: size of soluble fibrin(ogen) degradation products studied by electrophoresis and immunoblotting.

The aim of this study was to investigate the proteolytic degradation of fibrin(ogen), with special emphasis on the size of soluble fibrin(ogen) derivatives identified before, during and after intra-arterial catheter-directed thrombolysis with alteplase. Arteriography was performed before thrombolysis and after 0.5, 3, 10 and 24 h in six patients with peripheral native artery or bypass occlusions. Samples collected simultaneously intra-arterially from the thrombus and from venous blood were studied by immunoblotting patterns obtained after polyacrylamide and agarose gel electrophoresis. Supernatant from centrifuged material aspirated from the thrombus before thrombolysis contained soluble fibrin(ogen) derivatives with molecular weights of several thousand kDa. Two types of soluble fibrin(ogen)-related material were visualized during treatment: high molecular weight species (500-1000 kDa) displaying an almost continuous spectrum of molecular weights, suggesting gradual proteolytic degradation of cross-linked fibrin into X-oligomeric material; and X, Y, DD, D and E fragments. The amount and distribution of fragments strongly indicated that preferential fibrinolysis had taken place. The finding of a sustained level of fragments in post-thrombolytic plasma might indicate that insoluble fragments embolize peripherally and subsequently lyse. A close association between angiographical and molecular findings during both successful and failing thrombolysis was demonstrated.

Soluble, thrombin-related material in arterial thrombi and plasma studied during catheter-directed intra-arterial thrombolysis.

We investigated soluble, thrombin-related material in arterial thrombi and venous plasma during catheter-directed thrombolysis with alteplase. Arteriography was performed before thrombolysis and 0.5, 3, 10 and 24 h after the onset of treatment in six patients with (sub)acute lower extremity ischaemia caused by native artery or bypass occlusion. Samples were collected simultaneously from the thrombus and venous blood. After adding inhibitors of thrombin and plasmin, the centrifuged samples were assayed for prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT) and fibrinopeptide A (FPA). Levels of F1+2, TAT and FPA were extremely elevated in the thrombus-related samples before the blood flow was re-established (at 0 and 0.5 h) in all five successfully treated patients. In comparison, venous plasma levels of F1+2, TAT and FPA were moderately elevated, and reached a maximum at 3 h. In conclusion, material aspirated from lysing human thrombi formed in vivo contains large amounts of F1+2, TAT and FPA, but our methods prevented us from detecting enzymatically active thrombin.

Morphological abnormalities revealed after successful intra-arterial thrombolysis of infra-inguinal native arteries and bypasses.

PURPOSE: To characterise morphological abnormalities depicted after successful intra-arterial thrombolysis; to determine whether these differed in infra-inguinal native arteries and bypasses; and to evaluate whether balloon angioplasty was an appropriate treatment of stenoses in the acute phase after thrombolysis. MATERIAL AND METHODS: Patient records, radiology records, and angiograms from 47 patients with acute or subacute occlusions of infra-inguinal arteries (n = 21) or bypasses (n = 26) successfully treated with continuous intra-arterial infusion of streptokinase, urokinase or tissue plasminogen activator were retrospectively reviewed. RESULTS: Angiographic morphological abnormalities were depicted in 18 of 21 arteries (86%) and in 23 of 26 bypasses (88%), the most common abnormality being stenoses. Haemodynamically significant stenoses were found in 15 arteries (71%) and 18 bypasses (69%). The majority of the stenoses were successfully treated with balloon angioplasty, both in native arteries (12/15; 80%) and in bypasses (14/18; 78%). CONCLUSION: Morphological abnormalities are most often shown after successful intra-arterial thrombolysis in arteries, autogenous and non-autogenous bypasses. In all types of conduits, stenoses are the most commonly revealed lesion, which in the majority of cases can be treated with balloon angioplasty. Short-term outcome after catheter-directed thrombolysis and angioplasty seems fair.

[Catheter-directed thrombolytic therapy--a current alternative to proximal deep venous thrombosis]. / Kateterbasert trombolytisk behandling--aktuelt alternativ ved proksimal dyp venetrombose.

Deep venous thrombosis extending into the iliac veins is associated with significant acute and late morbidity despite adequate conventional treatment with heparin and oral anticoagulants. The purpose of this paper is to focus on a multidisciplinary, aggressive approach with catheter-directed thrombolysis, in which a catheter with many side-holes is placed within the thrombus and thrombolytics infused. The aim is to eliminate the thrombus, to provide unobstructed venous drainage from the affected limb, and to prevent recurrent thrombosis. Total recanalisation of the iliofemoral segment was achieved in three of four treated patients, while partial lysis was obtained in one patient with symptoms for four weeks. Two weeks after discharge, two patients had no symptoms, while two had a moderate leg oedema. All of the three women used oral contraceptives at the time of thrombus formation; two had hereditary thrombophilia. Most probably, successful catheter-directed thrombolysis will reduce the incidence of post-thrombotic syndrome, but there are no long-term follow-up studies after such treatment.

Mechanics of intraventricular filling: study of LV early diastolic pressure gradients and flow velocities.

This study investigates mechanisms of left ventricular (LV) intracavitary flow during early, rapid filling. In eight coronary artery disease patients with normal LV ejection fraction we recorded simultaneous LV apical and outflow tract pressures and intraventricular flow velocities by color M-mode Doppler echocardiography. In five anesthetized dogs we also recorded left atrial pressure and LV volume by sonomicrometry. In patients, as the early diastolic mitral-to-apical filling wave arrived at the apex, we observed an apex-outflow tract pressure gradient of 3.5 +/- 0.3 mmHg (mean +/- SE). This pressure gradient correlated with peak early apex-to-outflow tract flow velocity (r = 0.75, P < 0.05). The gradient was reproduced in the dog model and decreased from 3.1 +/- 0.3 to 1.7 +/- 0.5 mmHg (P < 0.05) with caval constriction and increased to 4.2 +/- 0.5 mmHg (P < 0.001) with volume loading. The pressure gradient correlated with peak early transmitral flow (expressed as time derivative of LV volume; r = 0.95) and stroke volume (r = 0.97). In conclusion, arrival of the early LV filling wave at the apex was associated with a substantial pressure gradient between apex and outflow tract. The pressure gradient was sensitive to changes in preload and correlated strongly with peak early transmitral flow. The significance of this gradient for intraventricular flow propagation in the normal and the diseased heart remains to be determined.