Deep vein thrombosis outcome and the level of oral anticoagulation therapy.

OBJECTIVE: The purpose of this study was to assess the rate of deep vein thrombosis (DVT) resolution and DVT outcomes as functions of the level of oral anticoagulation therapy achieved with warfarin. METHODS: In 33 consecutive patients, a series of 35 limbs with acute symptomatic DVT was followed throughout 1 year of anticoagulation therapy. All the patients underwent 5 days of intravenous unfractionated sodium heparin therapy that was adjusted in dose to prolong the activated thromboplastin time to 2.0 to 2.5 times the control. In addition, warfarin was administered for a period of 6 months, with a target international normalized ratio (INR) between 2.0 and 3.0. All the patients underwent venous duplex scanning and physical examination at the time of diagnosis and at 1 week, 1 month, 3 months, 6 months, and 1 year. RESULTS: At the end of the 1-year study period, the rate of complete DVT resolution was 68%. The median INR values in patients with complete DVT resolution were significantly higher than those of patients with incomplete DVT resolution after 1, 3, and 6 months of treatment with warfarin. In addition, the proportion of patients with INR values below therapeutic range was significantly higher in patients with incomplete DVT resolution than in patients with complete DVT resolution after 1, 3, and 6 months of treatment with warfarin. The presence of occlusive thrombi was associated with incomplete DVT resolution. Of the patients with occlusive thrombi, 62% had chronic venous insufficiency symptoms develop, whereas only 11% of the patients with nonocclusive thrombi (P =.003) had these symptoms develop. CONCLUSION: Despite 6 months of oral anticoagulant therapy, almost one third of thrombi did not resolve completely. The INR values were significantly higher in those patients with complete DVT resolution. These results suggest that the maintenance of an INR level between 2.0 and 3.0 throughout oral anticoagulation therapy will minimize the rate of incomplete DVT resolution.     

The limitations of impedance plethysmography in the diagnosis of acute deep venous thrombosis

We reviewed our experience with impedance plethysmography (IPG) and duplex scanning in the diagnosis of acute deep venous thrombosis (DVT) to determine their respective accuracy and current role in our noninvasive vascular laboratory. During a recent 22-month period 1776 patients were evaluated in our laboratory for DVT. Sixty patients (64 limbs) underwent ascending venography within 48 hours of testing (49 limbs were evaluated by all three modalities). With the venograms used as the reference standard, B-mode scanning correctly identified the presence of acute thrombus in 24 of 27 limbs (88.8%) and the absence of thrombus in 31 of 34 limbs (91.2%), for an overall accuracy of 90.6%. IPG alone was less sensitive (75%) and less specific (44.8%), with an overall accuracy of only 57.1%. Twenty-eight IPGs were performed on patients with negative venous scans. Two positive IPGs were the result of chronic venous occlusion and two others detected clinically significant isolated iliac vein thrombi, but 13 patients had false positive IPGs. One false negative IPG occurred. The difference in the sensitivity of scan alone vs scan plus IPG was not significant (chi 2 = 0.045; difference not significant), but the decrease in specificity was chi 2 = 17.3; p less than 0.001). The rarity of isolated iliac vein thrombosis and the high false positive rate for IPG do not justify its continued use if B-mode venous scanning is available. Although positive scan results may be used confidently to institute therapy without the need for venography, in high-risk patients with a strong clinical suspicion of proximal DVT despite a negative scan venography should be obtained before withholding anticoagulation.     

Pathogenesis, diagnosis, and treatment of postoperative deep vein thrombosis

Most postoperative deep vein thrombosis (DVT) arises from the venous systems of the pelvis and lower extremities, especially the soleal veins. Embolization of venous thrombi is related to the size and location of thrombi and movement of the lower limbs and commonly occurs within 1 week from the onset of formation. There are three steps in the final diagnosis of DVT: probable diagnosis by anamnesis and physical examination; screening diagnosis using quantitative tests; and definitive diagnosis using imaging tests. To determine embolic sources, venous echography, which is noninvasive and convenient, is the first choice. Therapeutic methods are selected based on thrombi extent and time after formation. Anticoagulant therapy is indicated in all cases except in patients with possible bleeding tendency and continues for 3 months or more. Among the endovascular therapies, catheter-directed thrombolysis is a more effective approach when combined with a temporary vena cava filter than operative thrombectomy. Although the prevention of DVT is mandatory for surgeons, it is difficult to avoid venous thromboembolism completely. Systemic early diagnosis and emergent therapeutic strategies for venous thromboembolism are clinically effective and promising.     

The natural history of calf vein thrombosis: Lysis of thrombi and development of reflux

Purpose: Although the fact is well accepted that deep venous thrombosis (DVT) of the iliac, femoral, and popliteal veins can lead to the post-thrombotic (postphlebitic) syndrome, the significance of isolated calf DVT on the development of late venous sequelae and physiologic calf dysfunction is unknown. The purpose of this study was to review the outcome of 58 limbs with isolated calf DVT and report the clinical, physiologic, and imaging results up to 6 years after the onset of DVT. Methods: The study consisted of 58 limbs of 54 patients in whom isolated calf vein DVT was diagnosed between 1990 and 1995. Proximal propagation of clot, lysis of thrombi, and development of symptomatic pulmonary emboli were examined. Of the patients, 28 received anticoagulation therapy, and 26 did not, but they had follow-up with serial duplex scans. At late follow-up 1 to 6 years later (median, 3 years), 23 patients were examined for the post-thrombotic syndrome, and all 23 underwent clinical examination, color-flow duplex scanning, and air plethysmography. Results: Proximal propagation of DVT from the calf veins into the popliteal or thigh veins occurred in 2 of 49 cases (4%) within 2 weeks of diagnosis. No patient had clinically overt pulmonary emboli develop regardless of whether anticoagulation therapy was received or not. The most common site for calf DVT was the peroneal vein (71%). Complete lysis of calf thrombi was found in 88% of the cases by 3 months. At 3 years, 95% of the patients were either asymptomatic or mildly symptomatic, and 5% had discoloration of the limb. No ulcers occurred. By air plethysmography, physiologic abnormalities were found in 27% of the cases, which was not significantly different from normal controls. Valvular reflux by duplex scanning of the calf vein segment with DVT was found in 2 of 23 cases (9%). However, reflux in at least one venous segment not involved with DVT was found in 7 of 23 cases (30%), which was higher than, but not statistically different from, normal controls, with reflux occurring in 5 of 26 cases (19%). Conclusions: Isolated calf vein DVT leads to few early complications (ie, clot propagation, pulmonary emboli) and few adverse sequelae at 3 years. The peroneal vein is most commonly involved and should be a part of the routine screening for DVT. Lysis of clot usually occurs by 3 months. Although valvular reflux rarely is found in the affected calf vein at 3 years, reflux may be found in adjacent uninvolved veins in approximately 30% of the cases. The question of whether this will lead to future sequelae, such as ulceration, will require longer follow-up. (J Vasc Surg 1998;28:67-74.)     

Patterns of venous insufficiency after an acute deep vein thrombosis

BACKGROUND: The purpose of this study was to investigate patterns of venous insufficiency during a 12-month period after an acute deep vein thrombosis. STUDY DESIGN: Seventy limbs in 67 patients with an acute deep vein thrombosis (DVT) involving 147 anatomic segments were evaluated with duplex scanning at 1 month, 3 months, 6 months, and 1 year. Venous segments were examined whether they were occluded, partially recanalized, or totally recanalized, and the development of venous reflux was evaluated. RESULTS: The segments investigated were the common femoral vein (38 segments), femoral vein (33 segments), popliteal vein (36 segments), and calf veins (40 segments). There were 35 limbs with isolated DVT and the remaining 35 had multisegment DVT. At 1 year, thrombi had fully resolved in 76% of the segments, 20% remained partially recanalized, and 5% were occluded. The venous occlusion was most predominant in the femoral vein (21%) at 1 year. On the contrary, rapid recanalization was obtained in calf veins than in proximal veins at each examination (p < 0.01). Deep vein insufficiency was detected as early as 1 month after development of DVT, and the reflux was most predominant in popliteal veins (56%), followed by femoral veins (18%). No reflux was found in calf veins. Multisegment DVTs had a significantly higher incidence of deep vein insufficiency than single segment DVTs at 1 year. Development of superficial venous insufficiency was found in 5 limbs (7%) and perforating vein insufficiency in 5 (7%). CONCLUSIONS: Lower extremity venous segments showed different proportions of occlusion, partial recanalization, and total recanalization. Calf veins showed more rapid recanalization than proximal veins. Venous reflux was noted as early as 1 month. The limbs involving multisegment DVTs on initial examination had a higher incidence of deep vein insufficiency and could require much longer followup studies.     

Extended lower limb venous ultrasound for the diagnosis of proximal and distal vein thrombosis in asymptomatic patients after total hip replacement.

OBJECTIVE: To assess the performance of extended lower limb venous ultrasound (US) for the diagnosis of asymptomatic deep vein thrombosis (DVT) and to estimate a 3-month DVT incidence on repeated US after total hip replacement. DESIGN: Diagnostic performance study and prospective cohort study. MATERIALS AND METHODS: US was compared to phlebography in 70 consecutive patients and interobserver agreement was assessed in the last 48 patients at day 8. US was repeated in these 48 patients at day 13 and day 90. RESULTS: Phlebography demonstrated a DVT in 18/70 (26%) patients, with five proximal and 13 distal and US in 23/70 (33%) patients, with eight proximal and 15 distal. Sensitivity and specificity of US with 95% CI were 94% (73-100) and 89% (76-96), respectively. Sensitivity in isolated distal vein thrombosis was 92% (67-99). The Kappa coefficient for agreement between observers was 0.84 (0.66-1.00). Follow-up showed a DVT in 15/48 (31%) patients on day 8, in 20/48 patients (42%) on day 13. DVT recurred in two patients during follow-up. CONCLUSIONS: The incidence of asymptomatic DVT is still significant despite prophylaxis but most DVTs remain distal and occur in the first 2 weeks. Extended US could replace phlebography for systematic screening in clinical trials using surrogate endpoints in view of its high accuracy and reliability.     

Duplex Venous Imaging: Role for a Comprehensive Lower Extremity Examination

Real-time compression ultrasound (CU) along with venous duplex imaging is the most commonly performed noninvasive vascular examination. It has become the definitive diagnostic test for most patients with deep venous thrombosis (DVT). Some practioners have recommended that CU alone of the common femoral vein (CFV) and of the popliteal vein (PV) are all that is required since a complete examination is time consuming and calf veins are difficult to visualize. However, if only the CFV and PV are examined, all patients with isolated superficial femoral vein (SFV) and calf DVT remain undiagnosed. The purpose of this study is to establish the value of a comprehensive venous duplex examination compared to CFV and PV compression alone for detecting both proximal and infrapopliteal DVT. From January 1996 through December 1997, the initial venous duplex examinations of 5767 extremities in 3067 patients were reviewed and results tabulated according to presence and location of clot. The ATL 3000 with a 7-14 mHz probe was utilized. Studies were interpreted as normal, proximal DVT (popliteal and above, with or without calf DVT), isolated calf, or isolated SFV deep venous thrombosis. If only the CFV and PV had been examined, 30.3% (isolated SFV + isolated calf vein DVT) of all DVT and 4.5% of proximal DVT would have been missed. A complete venous duplex examination altered the care in 288 (30.3%) of all patients examined who had DVT, and is therefore recommended as the standard noninvasive examination when evaluating patients for acute DVT.     

Endovenous laser therapy and radiofrequency ablation of the great saphenous vein: analysis of early efficacy and complications

BACKGROUND: Endovenous laser therapy (EVLT) and radiofrequency ablation (RFA) are new, minimally invasive percutaneous endovenous techniques for ablation of the incompetent great saphenous vein (GSV). We have performed both procedures at the Mayo Clinic during two different consecutive periods. At the time of this report, no single-institution report has compared RFA with EVLT in the management of saphenous reflux. To evaluate early results, we reviewed saphenous closure rates and complications of both procedures. METHODS: Between June 1, 2001, and June 25, 2004, endovenous GSV ablation was performed on 130 limbs in 92 patients. RFA was the procedure of choice in 53 limbs over the first 24-month period of the study. This technique was subsequently replaced by EVLT, which was performed on the successive 77 limbs. The institutional review board approved the retrospective chart review of patients who underwent saphenous ablation. According to the CEAP classification, 124 limbs were C2-C4, and six were C5-C6. Concomitant procedures included avulsion phlebectomy in 126 limbs, subfascial endoscopic perforator surgery in 10, and small saphenous vein ablation in 4 (EVLT in 1, ligation in 1, stripping in 2). Routine postoperative duplex scanning was initiated at our institution only after recent publications reported thrombotic complications following RFA. This was obtained in 65 limbs (50%) (54/77 [70%] of the EVLT group and 11/53 [20.8%] of the RFA group) between 1 and 23 days (median, 7 days). RESULTS: Occlusion of the GSV was confirmed in 93.9% of limbs studied (94.4% in the EVLT [51/54] and 90.9% in the RFA group [10/11]). The distance between the GSV thrombus and the common femoral vein (CFV) ranged from -20 mm (protrusion in the CFV) to +50 mm (median, 9.5 mm) and was similar between the two groups (median, 9.5 mm vs 10 mm). Thrombus protruded into the lumen of the CFV in three limbs (2.3%) after EVLT. All three patients were treated with anticoagulation. One received a temporary inferior vena cava filter because of a floating thrombus in the CFV. Duplex follow-up scans of these three patients performed at 12, 14, and 95 days, respectively, showed that the thrombus previously identified at duplex scan was no longer protruding into the CFV. No cases of pulmonary embolism occurred. The distance between GSV thrombus and the saphenofemoral junction after EVLT was shorter in older patients (P = .006, r(2) = 0.13). The overall complication rate was 15.4% (20.8% in the EVLT and 7.6% in the RFA group, P =.049) and included superficial thrombophlebitis in 4, excessive pain in 6 (3 in the RFA group), hematoma in 1, edema in 3 (1 in the RFA group), and cellulitis in 2. Except for two of the three patients with thrombus extension into the CFV, none of these adverse effects required hospitalization. CONCLUSION: GSV occlusion was achieved in >90% of cases after both EVLT and RFA at 1 month. We observed three cases of thrombus protrusion into the CFV after EVLT and recommend early duplex scanning in all patients after endovenous saphenous ablations. DVT prophylaxis may be considered in patients >50 years old. Long-term follow-up and comparison with standard GSV stripping are required to confirm the durability of these endovenous procedures.     

Five-year outcome study of deep vein thrombosis in the lower limbs

OBJECTIVE: Venous disease was evaluated in relation to post-thrombotic syndrome 5 years after deep venous thrombosis (DVT) in patients treated with a regimen of low-molecular-weight heparin (LMWH) and warfarin in a Hospital-in-the-Home program. METHODS: The presence of flow, reflux and compressibility in 51 patients (102 limbs, 54 with DVT and 48 without DVT) was assessed by duplex ultrasound scanning. Blood tests were carried out for prothrombotic screening. Venous disease was related to pathologic severity of post-thrombotic syndrome, characterized by the CEAP (clinical, etiologic, anatomic, pathophysiologic) classification on a scale of 0 to 6. RESULTS: In the 102 limbs studied, 30 patients (59%) had an underlying thrombophilic disorder. The most common cause of DVT was postoperation and prolonged immobilization not related to postoperation. The most common thrombophilic abnormalities were anticardiolipin antibody and a deficiency of protein C or S, or both. Twenty-six limbs (48%) had proximal involvement (proximal and proximal plus distal DVT); resolution (recanalization or normal vein) in these limbs was seen in 85% at 6 months and 96% at 5 years. After 5 years, 25 of these proximal DVT limbs (96%) developed reflux and there were 4 limbs in CEAP class 0, 8 in classes 1 to 3, and 14 in classes 4 to 6. All of the 28 limbs (52%) with distal DVT showed DVT resolution by 6 months. After 5 years, 10 limbs (36%) developed reflux, and 13 limbs were in class 0, 12 in classes 1 to 3, and 3 limbs in classes 4 to 6. No DVT was detected in the 48 contralateral limbs, but reflux was detected in 25 limbs (52%), predominately in the superficial veins (16 limbs, 64%). CONCLUSIONS: The resolution of thrombus was more rapid and complete in patients with distal DVT than in those with proximal DVT. Patients with proximal DVT developed a more severe form of post-thrombotic syndrome that was likely related to the development of deep venous reflux. An important finding of this study was an unexpectedly high incidence of venous reflux in the apparently unaffected limb. Although these non-DVT limbs were not investigated at presentation, our data is consistent with the hypothesis that DVT may result in a more systemic disorder of venous function.     

The anatomy of deep venous thrombosis of the lower extremity

BACKGROUND: The diagnosis, treatment, and long-term sequelae of lower extremity deep venous thrombosis (DVT) depend on the anatomic location and extent of the process, yet a lack of such fundamental knowledge has limited the development of effective protocols for managing patients with DVT. METHODS: Venograms with evidence of acute DVT were evaluated, and the extent of the thrombotic process was recorded and correlated with the clinical presentation. Thrombi were classified according to the venous segments involved and to the thrombus' isolation to one segment or multiple segments. The left-to-right ratio of the DVT was assessed for various etiologic subgroups. RESULTS: Among 2762 venograms performed in 2541 patients over a 10-year period, there were 885 cases (34.8%) of DVT documented. Of these cases, 344 cases (39%) were idiopathic, 307 cases (35%) were postoperative, 84 cases (10%) occurred in the setting of malignancy, and 70 cases (8%) occurred as the result of trauma. Distal thrombi were more common than proximal thrombi, with calf involvement in 734 patients (83%), femoropopliteal involvement in 470 patients (53%), and iliac involvement in 75 patients (9%). The most common site of thrombus was the peroneal vein, which was involved in 595 patients (67%). The ratio of left-to-right-sided DVT was 1.32:1 overall but was greater for proximal thrombi, with a ratio of 2.4:1 for iliac DVT versus 1.3:1 for infrainguinal DVT. The preponderance of left-sided DVT appeared to be related to the high-frequency, left common iliac vein involvement; the left-to-right ratio was much closer to equality (1.09:1) for isolated infrainguinal DVT. The anatomic configuration of the DVT was correlated with the etiologic subgroup; postoperative DVTs were more often distal, whereas DVT developing in the setting of malignancy was more frequently proximal and often right sided. Proximal, left-sided DVTs were common in the idiopathic subgroup, presumably as a result of undiagnosed left iliac vein webs. CONCLUSIONS: The frequency of distal vein involvement greatly exceeds that of proximal involvement in patients with DVTs. Proximal DVTs are more frequently left sided, whereas distal DVTs occur with a more equal left-to-right distribution. The anatomic extent of DVTs appears to depend on the etiology of the process. These observations may shed light on the pathophysiology of venous thrombosis. The findings are of value in planning therapeutic interventions directed at venous recanalization.     

Progress in the diagnosis of deep venous thrombosis: the efficacy of real-time B-mode ultrasonic imaging

Seventy-six limbs with clinically suspected acute deep venous thrombosis (DVT) were evaluated by means of ultrasonic imaging (UI) to define the ability of this technique to detect acute and chronic venous obstruction and to determine the origin and distribution of venous thrombi. UI was compared with ascending contrast phlebography in 46 limbs and was found to be 100% accurate in detecting both acute and chronic venous thrombosis. Overall, acute DVT was present in 63 of 76 limbs (83%) studied. Acute DVT was found in 24% and recurrent acute DVT in 76%. Our results indicate that although the calf veins are the most common site of involvement (89%), thrombi may frequently arise simultaneously in multiple anatomic sites. All limbs with recurrent acute DVT had evidence of previous calf thrombi but only 13% had previous proximal disease. This suggests that asymptomatic calf DVT is common and the prevalence of recurrent acute DVT is significantly greater than previously believed. We found UI is a practical, accurate, non-invasive method for investigating the pathogenesis of venous disease.     

Significance of the soleal vein for the pathogenesis of deep vein thrombosis leading to acute massive pulmonary thromboembolism

Prophylaxis of deep vein thrombosis (DVT) is a serious matter as the source of pulmonary thromboembolism (PTE) in hospitalized patients. Leg DVT is classified into three groups: iliac, femoral and calf types. Among them, calf type DVT is closely connected with PTE. Especially, soleal vein is the most frequent site of thrombi formation occurring with venous stagnation. Although most cases of soleal vein thrombosis are resolved soon without specific treatments: in around 20% of cases the thrombosis propagates to the proximal drainage vein as float thrombi e.g. from peroneal vein and posterior tibial vein to popliteal vein. Thereafter, the organization of thrombi leads to venous valve insufficiency, so-called postthrombotic syndrome. As a result, it worsens blood stagnation and induces recurrent thrombi formation. The broad prophylaxis of DVT in the soleal veins for inpatients is the most important point in the initial stage of hospitalization.     

Patterns and distribution of isolated calf deep vein thrombosis.

PURPOSE: In the search for calf deep vein thrombosis (DVT) with color-flow duplex scanning (CFDS), most vascular laboratories investigate only the posterior tibial and peroneal veins. Few laboratories assess the soleal and gastrocnemial veins. This study was designed to determine the patterns and distribution of isolated calf DVT, including the soleal and gastrocnemial veins. METHODS: In the last 3 years, 5250 patients (mean age, 66 +/- 15 years; range, 22 to 93 years) were referred to the vascular laboratory for clinical suspicion of DVT and underwent examination with CFDS. All superficial and deep named veins, excluding the anterior tibial from groin to ankle, were imaged. Of the deep veins in the calf, the peroneal, the posterior tibial, the gastrocnemial, and the soleal veins were examined throughout their length. RESULTS: DVT was detected in 14% of the patients. Isolated calf DVT was detected in 282 limbs of 251 patients (4.8%). No significant difference was noted for the sex (114 men vs 137 women; P =.15) or the limb preference (145 left vs 137 right; P =.5). The peroneal veins were most frequently involved, with 115 limbs (41%) affected. The soleal veins were involved in 109 limbs (39%), followed by the posterior tibial in 105 limbs (37%) and the gastrocnemial in 79 limbs (29%). Thrombus in the soleal vein alone was found in 57 limbs (20%), in the gastrocnemial in 48 limbs (17%), in the peroneal in 41 limbs (15%), and in the posterior tibial vein in 35 limbs (12%). Thrombus confined to a single or paired vein was found in 181 limbs (64%). Thrombus involving two different veins (27%) was the second most frequent pattern, and thrombus in three (7%) or four (1.4%) different veins was less prevalent. Isolated thrombosis in veins not routinely investigated was found in 113 limbs (40%; soleal, n = 57; gastrocnemial, n = 48; soleal + gastrocnemial, n = 8). Multifocal origin of thrombosis, defined as thrombi in two different veins that do not anatomically communicate, was identified in 63 limbs (22%). CONCLUSION: Forty percent of the patients with acute isolated calf DVT would be judged to have normal CFDS examination results if the muscular veins in the calf were not imaged. Multifocal origin of thrombosis was found in 22% of the involved limbs. The prevalence of thrombosis in any calf vein either alone or in combination is comparable. Accordingly, the soleal and gastrocnemial veins should be examined routinely.     

The comparative value of noninvasive testing for diagnosis and surveillance of deep vein thrombosis

This is a prospective analysis of 351 patients in two distinct groups undergoing ascending phlebography, impedance plethysmography (IPG), and/or phleborheography (PRG) within the same 24-hour period. One hundred twenty patients also had a 125I-fibrinogen uptake test (RFUT). The two patient groups consisted of the following: those patients evaluated because of suspicion of deep vein thrombosis (DVT) (diagnostic) and those patients at high risk for postoperative DVT (total joint replacement) who had routine noninvasive testing and ascending phlebography (surveillance). The overall sensitivities for IPG and PRG were significantly better in the diagnosis group (71% [69 of 97 patients] and 78% [82 of 105], respectively) compared with the surveillance group (20% [14 of 71] and 27% [17 of 63], respectively) (p less than 0.0001). The sensitivities for IPG and PRG detecting proximal (A/K) thrombi was 83% (68 of 82 patients) and 92% (79 of 86) in the diagnosis group compared with 32% (11 of 34) and 33% (9 of 27) in the surveillance group (p less than 0.0001). Although there was no difference in overall incidence of DVT between the diagnosis group (56%, 118 of 212 patients) and the surveillance group (55%, 76 of 139), the results can be explained by the difference in A/K thrombi (84% [99 of 118] and 47% [36 of 76]) (p less than 0.001) and occlusive A/K thrombi (84% [58 of 69] and 23% [7 of 31]) (p less than 0.0001), respectively. Of the patients with A/K thrombi, 97% (67 of 69) in the diagnosis group had hemodynamically detectable thrombi compared with only 48% (12 of 25) in the surveillance group (p less than 0.001). Combining the RFUT with the noninvasive studies for surveillance significantly improved the sensitivity for both A/K and distal thrombi. Patient selection also appears to have a significant influence on the results of the combination of IPG and RFUT when the current surveillance group is compared with similarly performed studies in a previously reported diagnosis group. The location and magnitude of thrombi in any patient population can be skewed depending on indications and timing of testing, thereby significantly affecting the sensitivity of noninvasive tests. IPG and PRG are reliable for evaluating patients with suspected DVT. However, patients with postoperative DVT have a high incidence of nonocclusive thrombi. Because noninvasive hemodynamic tests cannot identify accurately postoperative DVT, they cannot be used to generate epidemiologic data or as end points for studies evaluating efficacy of prophylaxis in patients undergoing total joint replacement, and anatomic studies of the deep venous system continue to be required.     

Duplex ultrasound diagnosis of lower limb deep venous thrombosis

To compare a non-invasive technique with contrast venography in the diagnosis of lower limb deep venous thrombosis (DVT), 355 patients (380 limbs) were examined over 15 months, using Duplex ultrasound. During this period, ascending venograms were performed in 53 of these patients (56 limbs) and the results were compared. Duplex detection of intraluminal thrombus was based on venous compressibility, Doppler-derived flow spectra, and visualization of thrombus within the lumen. Venography was designated the 'gold standard'. Duplex scanning had a sensitivity of 90.9%, and specificity of 91.3% in diagnosing DVT anywhere in the lower limb. Sensitivity, specificity, and accuracy were best in the femoral segment (95.2%, 100%, 98.2%, respectively), and fell slightly in the more distal limb: popliteal segment (90.4%, 97.1% and 94.6%), and calf veins (88.8%, 92.0% and 90.4%). These results indicate that duplex scanning produces sufficiently accurate data in the diagnosis of lower limb DVT to warrant its clinical use. It provides both the facility for diagnosis without the risks of contrast venography, and permits repeated imaging to follow the immediate progression of disease and efficacy of treatment.     

Early thrombus remodelling of isolated calf deep vein thrombosis.

OBJECTIVE: this prospective study was designed to evaluate the evolution of thrombus propagation and lysis in relation to patterns and distribution of isolated calf DVT. METHODS: fifty-two limbs in 48 patients mean age 59+/-15, range 24-78 years, with isolated calf DVT that had at least one exam within 10 days of DVT detection were included in the study. Patients with a documented episode of prior DVT or evidence of post-thrombotic changes during the initial ultrasound exam were excluded. The initial thrombus length, patterns and location of the thrombi were recorded. On follow-up the propagation and lysis patterns of the clot were studied. RESULTS: remodelling of the thrombus, excluding echotexture and vein diameter changes on ultrasound, occurred in 23 limbs, (44%). Ascending propagation only was seen in seven limbs (13%) descending propagation only in two (4%) and in both directions in five (10%). Propagation at least to popliteal vein was detected in seven limbs (13%). Thrombus developed or extended to initially uninvolved veins in six limbs (12%). Pulmonary embolism developed only in one patient (2%; 95% CI: 0-11%). The site and the size of thrombus or the number of veins involved in the baseline exam did not correlate with the remodeling of thrombus. Soleal and gastrocnemial veins were comparable with the posterior tibial and peroneal veins in terms of thrombus propagation and lysis. CONCLUSIONS: early thrombus remodelling occurs in 44% of limbs with isolated calf DVT. This includes ascending and descending thrombus propagation and lysis. Thrombus development or propagation to initially uninvolved calf veins is found in 12%. Thrombus remodelling does not appear to be related to size, site and patterns of thrombosis.     

The patterns and distribution of residual abnormalities between the individual proximal venous segments after an acute deep vein thrombosis

INTRODUCTION: The subsequent course of residual abnormalities after an acute deep vein thrombosis (DVT) can vary within individual venous segments. To investigate the pattern of response within the individual venous segment, we used sequential duplex scanning to determine whether certain segments are more likely to recanalize or remain occluded. METHODS: The anatomic segments involved in 63 above-knee DVTs were examined with duplex scanning at 1 week, 1 month, 6 months, and 1 year after the acute event. The segments under investigation were the external iliac vein (EIV), common femoral vein (CFV), superficial femoral vein (SFV), and popliteal vein (PV). Reflux studies were performed at each follow-up examination. During the follow-up period the segments were examined to see whether they were occluded, partially recanalized, or totally recanalized and the development of reflux was noted. RESULTS: Most DVTs were multisegmental with a total number of 171 sites involved. Initially, a greater number of segments were occluded (71%) than partially thrombosed (29%). The occluded segments were predominantly in the SFV and PV. At 1 year the thrombi had fully resolved in 60% of the venous segments, 27% remained partially recanalized, and 13% were occluded. The venous segments that resolved within the first 6 months had a higher rate of valvular competence than those that resolved from 6 months to 1 year. The SFV and PV had a higher incidence of valvular incompetence than the EIV and CFV. All venous segments that were partially recanalized at 1 year were found to have significant reflux. The SFV had the highest incidence of total occlusion at the end of 1 year (36%). Many of the occluded SFVs had established collateral pathways that displayed no evidence of reflux. CONCLUSION: The lower extremity venous segments differ in respect to their tendencies to partially or fully recanalize or remain occluded. All partially recanalized segments displayed reflux. Fully resolved segments that recanalized within the first 6 months were more likely to have competent valves than those that recanalized after 6 months. In the presence of an occluded SFV, collateral pathways establish rapidly. No reflux was found in these collaterals.     

下肢深静脉血栓形成后综合征的腔内治疗

目的:探讨下肢深静脉血栓形成后综合征(PTS)的血管腔内微创治疗效果.方法:回顾性分析7年间收治的262例(275条肢体)下肢深静脉PTS患者的临床资料.患者均行局部麻醉下的血管腔内微创介入治疗.其中经皮血管腔内成形74条肢体,血管成形联合支架置入201条肢体.结果:手术成功268条肢体(97.5％),闭塞血管完全开通,恢复正常的血液回流;7条肢体未能完全开通(左髂总静脉段未能开通)经腰升静脉回流或侧支代偿.240例(91.6％) 253条肢体获随访8～96个月,平均(48.3±20.2)个月,其中完全缓解94条肢体(37.2％);明显缓解152条肢体(60.0％);轻度缓解7条肢体(2.8％).结论:下肢深静脉PTS的微创介入治疗创伤小、恢复快、疗效可靠.     

军训伤致急性下肢深静脉血栓形成的介入治疗

目的探讨多种介入方法相互配合对军训伤所致急性下肢深静脉血栓形成（deep venous thrombosis,DVT）的疗效。方法对军训伤所致25例急性DVT行Fogarty导管取栓术,其中单纯取栓3例,取栓联合球囊导管血管成形6例,血管成形联合血管腔内超声消融11例,血管成形和（或）血管腔内超声消融联合支架置入5例。结果髂股段静脉完全开通24例,除2例造影术无血管狭窄,1例管腔直径〉90%未行扩张外,16例狭窄段血管经球囊扩张后管腔直径≥71%,5例狭窄段扩张后残留管腔狭窄仍〉50%,置入相应大小的支架;左髂总静脉开口未能开通1例。25例随访2-70个月,平均34个月,21例临床症状、体征完全消失;3例训练后患肢周径比健侧增粗0.5-1.0cm,经休息、抬高患肢或穿戴血管弹力袜后好转,可从事正常军事训练;1例髂静脉未开通者训练后仍感肢体肿胀。结论多种外科介入技术相互配合可明显提高军训伤所致DVT疗效。     

Free-floating iliofemoral thrombus. A risk of pulmonary embolism

We retrospectively evaluated the risk of pulmonary embolism in hospitalized patients with venographically proved iliofemoral deep vein thrombosis (DVT). Venograms and clinical records of 78 patients with iliofemoral DVT were reviewed and the proximal intraluminal thrombus was characterized as free-floating (greater than 5-cm nonadherent segment) or occlusive (no free-floating elements). The incidence of pulmonary embolism confirmed by high-probability radioisotope ventilation-perfusion lung scanning within ten days following venography was 9% (7/78) and was associated with 60% (3/5) free-floating and 5.5% (4/73) occlusive phlebographic criteria (P less than .05). All patients who experienced pulmonary embolism were given therapeutic heparin treatment (partial thromboplastin time, more than twice the control value). The mean (+/- SD) time from the diagnosis of DVT to pulmonary embolism was 104 +/- 60 hours, and 120 +/- 71 hours for patients with free-floating and occlusive thrombi, respectively (P greater than .05). Patients with iliofemoral DVT that met free-floating criteria are at significant risk for pulmonary embolism, despite the administration of heparin.