Deep venous thrombosis: rate of spontaneous lysis and thrombus extension.

AIM: Although recanalization occurs after an episode of venous thrombosis, the exact timing for this process, the rate of clearing at the different venous segments and the nature of the mechanisms involved and their progression are not well known. Recognition of these competing events is important in understanding the natural history and the mechanisms responsible for lysis of the thrombus and for the development of the post-thrombotic syndrome METHODS: During the course of 5 consecutive years, 110 patients (126 legs) with deep vein thrombosis (DVT) were prospectively followed using ultrasonic duplex. Follow-up studies were performed at intervals of 1 and 7 days, 1 month, every 3 months for the 1(st) year, and yearly thereafter. Mean duration of follow-up was 329 days. RESULTS: When only legs with initial complete occlusion are considered, the prevalence of occlusion progressively decreases to 33% after 6 months, 17% after the 1(st) year, and 0% after 3 years. Recanalization of individual segments occurred even more rapidly. After 3 months, recanalization of completely occluded segments was present in 93% of common femoral veins, 79% of superficial femoral veins (proximal segment), 84% of popliteal veins, and 72% of posterior tibial veins. The rate of recanalization was highest for multisegmental disease. Propagation of thrombi to adjacent venous segments occurred in 15% of the limbs. Propagation was usually limited to 1 or 2 adjacent segments. CONCLUSION: Lysis occurred early and was progressive. After 1 year most legs have recanalized. After 3 years recanalization occurred in all legs although residual thrombosis (partial obstruction) was still present in 50% of the limbs. Propagation of the thrombus was a limited process.

Markers of plasma coagulation and fibrinolysis after acute deep venous thrombosis.

OBJECTIVE: Plasma markers of coagulation and fibrinolysis have proved sensitive in the initial diagnosis of acute deep venous thrombosis (DVT). The purpose of this study was to examine the evolution and utility of measuring D-dimer and prothrombin fragment 1+2 (F 1+2) levels after an acute DVT. METHODS: Subjects with DVT confirmed by ultrasonography had quantitative plasma D-dimer and F 1+2 levels determined before anticoagulation. Ultrasound scan and coagulation studies were repeated at 3, 7, and 14 days; 1 month; and every 3 months for 1 year. RESULTS: Sixty-one patients with a median initial thrombus score of 3 (interquartile range, 2-7) were followed up for 266 days (interquartile range, 91.5-364 days). Initial D-dimer levels were elevated in 92.7% of patients and were associated with thrombus extent (P =.003), whereas F 1+2 levels were increased in 94.5% of patients and were lower in patients with isolated calf vein thrombosis (P =.001). Initial D-dimer (P =.002) and F 1+2 levels (P =.009) were significantly higher in the 26 (43%) patients with recurrent thrombosis during follow-up. Initial D-dimer levels of 2000 ng/mL or greater were predictive of recurrent events after both proximal and isolated calf vein thrombosis. Although interval increases in these markers had little value in detecting recurrent thrombotic events, D-dimer levels of 1000 ng/mL or greater and 500 ng/mL or greater had respective sensitivities of 89.3% and 100% in detecting early and late recurrences. Corresponding specificities were 35.6% and 53.9%. CONCLUSIONS: Initial D-dimer levels are determined by total thrombus load and remain elevated long after an acute DVT. F 1+2 levels are less sensitive to thrombus score and return to baseline more quickly. Initial levels of these markers may have some utility in predicting the risk of ultrasound scan-documented recurrences, whereas increased D-dimer levels are a sensitive but nonspecific marker of these events.

Deep venous thrombosis and superficial venous reflux.

OBJECTIVE: Although superficial venous reflux is an important determinant of post-thrombotic skin changes, the origin of this reflux is unknown. The purpose of this study was to evaluate the frequency and etiologic mechanisms of superficial venous reflux after acute deep venous thrombosis (DVT). METHODS: Patients with a documented acute lower extremity DVT were asked to return for serial venous duplex ultrasound examinations at 1 day, 1 week, 1 month, every 3 months for the first year, and every year thereafter. Reflux in the greater saphenous vein (GSV) and lesser saphenous vein (LSV) was assessed by standing distal pneumatic cuff deflation. RESULTS: Sixty-six patients with a DVT in 69 lower extremities were followed up for a mean of 48 (SD +/- 32) months. Initial thrombosis of the GSV was noted in 15 limbs (21.7%). At 8 years, the cumulative incidence of GSV reflux was 77.1% (SE +/- 0.11) in DVT limbs with GSV involvement, 28.9% (+/- 0.09%) in DVT limbs without GSV thrombosis, and 14.8% (+/- 0.05) in uninvolved contralateral limbs (P <.0001). For LSV reflux, the cumulative incidence in DVT limbs was 23.1% (+/- 0.06%) in comparison with 10% (+/- 0.06%) in uninvolved limbs (P =.06). In comparison with uninvolved contralateral limbs, the relative risk of GSV reflux for DVT limbs with and without GSV thrombosis was 8.7 (P <.001) and 1.4 (P =.5), respectively. The relative risk of LSV reflux in thrombosed extremities compared with uninvolved extremities was 3.2 (P =.07). Despite these observations, the fraction of observed GSV reflux that could be attributable to superficial thrombosis was only 49%. CONCLUSIONS: Superficial venous thrombosis frequently accompanies DVT and is associated with development of superficial reflux in most limbs. However, a substantial proportion of observed reflux is not directly associated with thrombosis and develops at a rate equivalent to that in uninvolved limbs.

Venous thrombus stability during acute phase of therapy.

The purpose of this study was to use serial venous duplex scans to document the status of deep venous thrombi during the early phase of therapy for acute, deep-vein thrombosis (DVT). A total of 71 consecutive participants treated for a first episode of acute DVT were monitored for new venous thrombosis using serial venous duplex scans. An average of 4.6 duplex scans were performed per patient (range, three to seven) during the 3-week study period. The cumulative incidence of contiguous/non-contiguous extension of the DVT at 3 weeks was 26% (95% CI = 14% to 38%). Nine of the 15 (60%) occurrences were asymptomatic. None of the classical risk factors for DVT was significantly associated with the development of new thrombi. The fraction of time during which the level of anticoagulation was considered 'adequate' (international normalized ratio > or =2.0 and/or heparin concentration > or =0.2 IU/ml) was inversely associated with the risk of extension/new thrombi (p = 0.01, Cox proportional hazards analysis). It was concluded that: (1) the frequency of contiguous/non-contiguous extension of venous thrombosis detectable during the first 3 weeks of therapy was higher than previously reported; (2) the majority of the occurrences were asymptomatic; and (3) the risk of developing this complication was inversely associated with the level of anticoagulation achieved.

Determinants of chronic venous disease after acute deep venous thrombosis.

PURPOSE: The purpose of this investigation was to evaluate the relationship between the presenting features of an acute deep venous thrombosis (DVT), the subsequent natural history of the thrombus, and the ultimate outcome as defined according to the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery reporting standards in venous disease. METHODS: Patients with an acute DVT were followed with serial clinical and ultrasound examinations. Thrombus extent within 7 venous segments was scored retrospectively according to the reporting standards (scores ranged from 0 to 3), and segmental reflux was scored as present (1) or not present (0). The initial and final thrombus scores, the rates of recanalization and rethrombosis, and the total reflux scores were then calculated from these grading scales and related to ultimate chronic venous disease (CVD) classification. RESULTS: Sixty-eight patients with an acute DVT in 73 limbs were followed for 18 to 110 months (mean, 55 +/- 26 months). At the completion of the follow-up period, 20 extremities (27%) were asymptomatic (class 0), 13 (18%) had pain or prominent superficial veins (class 1), 25 (34%) had manifested edema (class 3), 13 (18%) had developed hyperpigmentation (class 4), and 2 (3%) had developed ulceration (class 5). In a univariate analysis, CVD classification was correlated with the reflux score (P =.003) but not with the initial or final thrombus score or with the rate of recanalization or rethrombosis. In a multivariate model of features documented at presentation, only the tibial thrombosis score was a significant predictor of CVD classification (R2 =.06). Outcome was better predicted (R2 =.29) with a model that included variables defined during follow-up the final reflux score, the final popliteal score, and the rate of recanalization. CONCLUSION: The ability to predict the severity of CVD after an acute DVT is currently limited, although the natural history appears more important than the presenting features of the event. The extent of reflux, the presence of persistent popliteal obstruction, and the rate of recanalization are related to ultimate CVD classification, but other determinants remain to be identified.

Early outcome after isolated calf vein thrombosis.

PURPOSE: The clinical significance of isolated calf vein thrombosis (CVT), particularly with respect to development of the postthrombotic syndrome, remains controversial. The purpose of this study was to define the early natural history of CVT in relation to persistent lower extremity symptoms, propagation, recanalization, and the development of valvular incompetence. METHODS: Over a 116-month period, 499 patients with acute deep venous thrombosis (DVT) were referred to our research laboratory, of whom 58 (12%) had thrombosis confined to the calf veins of at least one extremity. The lower extremities of 268 patients (29 with isolated CVT) were followed-up clinically and with duplex ultrasonography at intervals of 1 day, 7 days, 1 month, every 3 months for the first year, and yearly thereafter. RESULTS: Seventy percent of extremities with CVT were symptomatic at presentation. Although the prevalence of clinical signs and symptoms decreased to 29% by 1 month, 23% of patients had persistent pain, edema, or both at 12 months. In contrast, 9% of uninvolved extremities contralateral to a CVT and 54% of extremities with proximal DVT remained symptomatic at 1 year (p = 0.004). Recanalization proceeded rapidly such that the mean thrombus load was reduced by 50% at 1 month and to zero at 1 year. The prevalence of valvular incompetence progressively increased such that reflux was present in 24% of extremities at 1 year. Although its investigation was not a primary goal of this study, pulmonary embolism was diagnosed at presentation and during follow-up in 11% and 3% of patients, respectively. CONCLUSIONS: The natural history of CVT is complicated by persistent symptoms and the development of valvular incompetence in approximately one-quarter of patients. This potential for persistent lower extremity symptoms should be considered in evaluating the clinical relevance of isolated calf vein DVT.

The relationship of venous diameter to reflux, cephalad thrombus and cephalad reflux following deep venous thrombosis.

Duplex ultrasonography was used to measure the diameters of the common femoral, superficial femoral and popliteal vein segments in 123 patients following DVT. A cross sectional analysis was done based on the most recent visit to determine chronic venous diameter changes following DVT. Venous diameters in recanalized segments were smaller at all levels compared to those never occluded (p = 0.06 for CFV and p < 0.05 for SFV and PV). After accounting for a previous history of occlusion, the diameters of the segments with and without reflux were not significantly different. There was also no evidence of venodilation in segments caudal to cephalad reflux or thrombus. Recanalized veins are smaller in diameter than those which were never thrombosed. Cephalad thrombus or reflux is not associated with venodilatation of caudal segments. Reflux following DVT is probably secondary to valvular damage rather than hypertension, since there was no diameter difference between refluxing and non-refluxing segments.

The site of residual abnormalities in the leg veins in long-term follow-up after deep vein thrombosis and their relationship to the development of the post-thrombotic syndrome.

Two major sequelae of deep vein thrombosis (DVT), obstruction to outflow due to the presence of residual thrombus and reflux due to valvular damage, may contribute to the development of the post-thrombotic syndrome (PTS). We studied the nature and site of residual abnormality, non-invasively with duplex ultrasound, in the veins of 69 limbs in 66 patients, 1 to 6 years after primary acute DVT. There were clinical features of the PTS in 27 limbs and 42 legs were asymptomatic. The pattern of duplex abnormalities was complex and varied for both the PTS and asymptomatic groups. The proportion of abnormal common and external iliac veins and abnormal common, deep and superficial femoral veins was similar for limbs with the PTS and asymptomatic limbs. Twenty-six per cent of legs with the PTS had reflux at the saphenofemoral junction compared with 19% asymptomatic legs (difference not significant). The PTS was associated with proportionally more abnormal popliteal veins (81% vs 55%) and posterior tibial veins (PTV), PTV#1 (41% vs 21%) and PTV#2 (41% vs 14%) when compared with asymptomatic limbs. The odds ratio for a popliteal vein abnormality being associated with the PTS was 3.63 (95% CI 1.16 to 11.43). The odds ratios for PTV#1 and PTV#2 abnormalities in association with the PTS compared to asymptomatic limbs were 2.52 (95% CI 0.87 to 7.31) and 4.13 (95% CI 1.30 to 13.11). In conclusion, residual venous abnormalities after DVT are common and when present in the popliteal and tibial veins are associated with an increased likelihood of PTS expression.

Venous valvular reflux in veins not involved at the time of acute deep vein thrombosis.

PURPOSE: The aim of this study was to determine whether, in lower extremities with documented episodes of acute deep venous thrombosis (DVT), incompetence develops in veins that were not the site of thrombosis. METHODS: Patients were monitored with serial duplex ultrasonography at 1 day, 1 week, 1, 3, 6, 9, and 12 months, and then annually after detection of acute DVT. The following venous segments were analyzed: common femoral, greater saphenous, proximal superficial femoral, deep femoral, popliteal, and posterior tibial. The incidence of reflux development in both thrombosed and uninvolved segments was determined. Reflux was categorized as either transient or permanent. RESULTS: A total of 227 limbs in 188 patients were serially studied. Mean follow-up was 19.9 months (range 1 to 88 months). Overall, 403 of the 1423 segments (28.3% +/- 2.3%) developed reflux during the study, of which 118 (29.3% +/- 4.4%) had no prior or concurrent history of thrombosis. Considering only the segments that developed incompetence, the percent without prior thrombosis at each level was as follows: common femoral vein (40.0%), greater saphenous vein (53.1%), deep femoral vein (20.6%), proximal superficial femoral vein (23.9%), popliteal vein (8.9%), and posterior tibial vein (31.9%). Valvular insufficiency developing in segments uninvolved with thrombus was more likely to be transient (40.2%) than was the reflux in thrombosed segments (22.6%). This difference was statistically significant (p < 0.05). CONCLUSIONS: Permanent venous valvular damage can occur in the absence of thrombosis after DVT. Reflux in uninvolved venous segments has a different anatomic distribution and is more likely to be transient than the incompetence associated with thrombosis.

Propagation, rethrombosis and new thrombus formation after acute deep venous thrombosis.

PURPOSE: The purpose of this study was to determine the incidence, timing, and outcome of further thrombotic events after an initial episode of acute deep venous thrombosis. METHODS: Venous thrombi in 204 lower extremities (177 patients) were monitored with duplex ultrasonography at intervals of 1 day, 7 days, 1 month, every 3 months for 1 year, and yearly thereafter. RESULTS: Among initially involved extremities, propagation to new segments occurred in 61 (30%) and rethrombosis occurred in 63 (31%). Both propagation and rethrombosis, in different segments, occurred in 27 (13%) extremities. New thrombi were also noted in nine (6%) initially uninvolved extremities. These events were not associated with identifiable clinical risk factors, although extremities with rethrombosis were more extensively involved at presentation. Propagation in initially involved extremities was an early event, occurring within a median of 40 days in all segments. New thrombotic events in initially uninvolved extremities and rethrombosis occurred as later events. The development of reflux was significantly more common among all initially uninvolved segments to which thrombus extended and among mid and distal superficial femoral and popliteal artery segments with rethrombosis. CONCLUSIONS: Recurrent thrombotic events are common after acute deep venous thrombosis and adversely affect the ultimate development of valvular incompetence. Their occurrence is unrelated to recognized clinical risk factors and can occur despite standard anticoagulation measures.

Relationship between changes in the deep venous system and the development of the postthrombotic syndrome after an acute episode of lower limb deep vein thrombosis: a one- to six-year follow-up.

PURPOSE: This study investigated changes in the deep venous system and the development of the postthrombotic syndrome (PTS) after an episode of acute deep vein thrombosis (DVT). METHODS: Seventy-eight patients (41 male patients, 37 female patients) with acute DVT in 83 legs (31 right, 42 left, five bilateral) underwent annual follow-up examinations for 1 to 6 years (median, 3 years) for symptoms and signs of the PTS. A venous duplex scan was performed at each visit to detect obstruction and reflux in the veins, both of which may contribute to the development of the PTS. DVT was primary in 69 limbs and recurrent in 14 limbs. RESULTS: When last examined 49 limbs were free of symptoms, and 34 had the PTS (23 edema only, 11 hyperpigmentation). Only two patients had ulcers during the follow-up period; both patients had the ulcers in areas of hyperpigmentation in limbs with recurrent DVT. The extent of disease was similar in limbs with the PTS (79% multisegment, 18% single segment) and those without the PTS (69% multisegment, 12% single segment). In limbs with the PTS the deep veins were normal in only one (3%), six (18%) showed reflux only, five (15%) obstruction only, and 22 had features of both obstruction and reflux (65%). In limbs without the PTS the deep veins showed no abnormality in nine (18%), reflux only in 17 (35%), obstruction only in six (12%), and reflux with obstruction in 17 (35%). In the 11 limbs with hyperpigmentation nine had obstruction and reflux noted, one had obstruction only, and one had reflux alone. CONCLUSIONS: After an episode of acute DVT 12% of the limbs returned to normal by duplex criteria. Although only 13% developed skin complications, 41% had features of the PTS. Limbs with the PTS had more than three times the odds of having combined reflux and obstruction than did limbs without the PTS (odds ratio = 3.5, 0.95 confidence intervals = 1.4, 8.6). Continued study of these patients will determine the course of those limbs with venous abnormalities that have not yet developed symptoms and signs of the PTS.

Venous diameter and compliance after deep venous thrombosis.

Duplex sonography was used to measure diameters of the common femoral, superficial femoral, and popliteal veins in 56 patients followed for more than 6 months after DVT and in 17 normal subjects. Diameter changes with Valsalva's maneuver were also measured as an index of venous compliance. Among patients with unilateral thrombosis, segments with residual disease were 0.07 to 0.28 cm smaller than the contralateral disease-free side (p < 0.05 for CFV and SFV) with a diameter index (ipsilateral/contralateral diameter) significantly less than that of normal subjects. In contrast, completely recanalized segments were not significantly different from the contralateral side and had diameter indices indistinguishable from normal subjects. Distensibility with Valsalva's maneuver was not significantly different from normal in DVT patients with either resolved or residual disease. Venous diameter does decrease following DVT, but returns to normal following complete recanalization and is not associated with chronic venous compliance changes.

A comparison of the cuff deflation method with Valsalva's maneuver and limb compression in detecting venous valvular reflux.

OBJECTIVE: This study was designed to test the results of Valsalva's maneuver and limb compression against the standing-cuff inflation-deflation method for the detection of venous valvular reflux. DESIGN: The study was conducted in 67 patients (134 extremities) who had an episode of deep vein thrombosis. An ultrasonic duplex scanner was used to evaluate two methods of testing for reflux. The most commonly used methods are Valsalva's maneuver and limb compression, both of which can raise the venous pressure and promote reflux. With the cuff method, the patient is studied in the standing position. The cuffs are segmentally placed (thigh to foot) with reflux encouraged when the inflated cuff is suddenly deflated. SETTING: The patients were a part of a long-term natural history study of acute deep vein thrombosis and its effects on venous valve function. OUTCOME MEASURES: Valvular reflux was documented by the appearance of retrograde flow in the vein when the normal transvalvular pressure gradient was reversed. RESULTS: Both limb compression and Valsalva's maneuver can elicit reflux, but the maneuvers are difficult to standardize and come up with meaningful results. With the cuff inflation-deflation method, the time to valve closure was less than 0.5 seconds in 95% of normal subjects. The results were easier to quantify and worked well for all segments of the venous systems--superficial and deep. CONCLUSIONS: The cuff inflation-deflation method provides more uniform quantifiable results for detecting reflux in the superficial and deep veins of the leg.

Incidence and time of occurrence of valvular incompetence following deep vein thrombosis.

Commencing December 1986 and over the course of 4 years, the diagnosis of acute deep vein thrombosis (DVT) was established by duplex scanning in 286 patients referred to the University of Washington Medical Center in order to rule out this problem. From this group 107 patients (123 legs with DVT) were placed in a long-term follow-up program. The documentation of valvular reflux and its site was demonstrated by duplex scanning. The duplex studies were done at intervals of 1 and 7 days, 1 month, every 3 months for the first year and then yearly thereafter. The mean follow-up time was 341 days. The presence of reflux was also determined in 502 patients with a negative duplex study and no previous history of DVT or chronic venous insufficiency. In the patients with acute DVT, valvular incompetence was noted in 17 limbs (14%) at the time of the initial study. Reflux was absent in 106 limbs (86%). In this last group reflux developed in 17% of the limbs by day 7. By the end of the first month, 37% demonstrated reflux. By the end of the first year, more than two-thirds of the involved limbs had developed valvular incompetence. The distribution of reflux at the end of the first year of follow-up was: 1) popliteal vein, 58%; 2) superficial femoral vein, 37%; 3) common femoral vein, 33%; and 4) posterior tibial vein, 18%. Reflux in the greater saphenous vein occurred in 25% of the limbs after 1 year. Reflux developed more frequently in thrombosed venous segments.(ABSTRACT TRUNCATED AT 250 WORDS)

Deep venous insufficiency: the relationship between lysis and subsequent reflux.

PURPOSE: Although venous valvular insufficiency is well recognized as the most important etiologic mechanism in the development of the postthrombotic syndrome, the factors contributing to valve incompetence after deep venous thrombosis remain obscure. METHODS: To establish the relationship between recanalization and valve competence, 113 patients with acute deep venous thrombosis were studied with serial duplex ultrasonography. RESULTS: Median lysis times for segments developing reflux (214 to 474 days) were 2.3 to 7.3 times longer than for corresponding segments not developing reflux (65 to 130 days) for all except the posterior tibial vein. In the posterior tibial vein, median lysis times for those with and without reflux were nearly identical (72 vs 80 days). The median time to onset of reflux was significantly less than the median lysis time in the mid and distal superficial femoral veins and was simultaneous with recanalization in all other segments. CONCLUSIONS: Early recanalization is important in preserving valve integrity for all but the posterior tibial segment. However, the small number of patients with reflux despite early lysis (< 1 month) or without reflux despite relatively late lysis (> 9 to 12 months) suggests that other factors may also contribute to the development of valvular incompetence. These factors may be particularly important in the posterior tibial vein, in which lysis time has little relationship to the ultimate development of reflux.

The potential role of thrombolytic therapy in venous thrombosis.

BACKGROUND: Anticoagulant therapy for lower extremity deep-vein thrombosis (DVT) has been shown to reduce mortality from pulmonary embolism, but subsequent morbidity from the postthrombotic syndrome remains high. Thrombolytic therapy produces higher lysis rates of venous thrombi than heparin alone. Some studies suggest a lower incidence of postthrombotic sequelae after early use of streptokinase. These potential benefits are limited to those patients without contraindications for this therapy. METHODS: For the past 3 years we have prospectively studied patients with DVT documented by duplex scanning. The records of these patients were reviewed to determine what proportion of this population would have been candidates for thrombolytic therapy. For this analysis, contraindications to the use of thrombolytic agents included: (1) recent surgery (less than 1 month); (2) recent major trauma; (3) active or recent bleeding; (4) brain disease (cerebrovascular accident, brain tumor, arteriovenous malformation); (5) pregnancy; and (6) bleeding diathesis. Also, patients with prior ipsilateral DVT and those with acute symptoms present for 7 or more days were not considered to be candidates for thrombolytic therapy. RESULTS: A contraindication to thrombolytic therapy was present in 194 (93%) of 209 patients with a diagnosis of DVT, including four patients with a relative contraindication. Two or more contraindications were present in 65 cases (31%). Recent surgery was the most frequent factor precluding therapy, being present in 71 patients. A history of DVT in the affected leg was present in 45 patients. CONCLUSIONS: Only 15 (7%) of 209 patients with DVT exhibited no contraindications for thrombolytic treatment. Only a small fraction of patients with venous thrombosis will be potential candidates for this therapy.

Pattern and distribution of thrombi in acute venous thrombosis.

The location and extent of thrombosis in the deep venous system will determine immediate and long-term outcome. During the past 3 years, we have studied by duplex scanning 833 patients with suspected deep vein thrombosis. In this group, 209 patients (25%) had a positive study. The findings relative to location and extent of involvement are as follows. (1) The right leg was involved in 35% of patients, the left leg in 48%. Bilateral involvement was noted in 17%. (2) The veins most frequently affected by deep vein thrombosis were as follows: superficial femoral in 74%, popliteal in 73%, common femoral in 58%, posterior tibial in 40%, deep femoral in 29%, greater saphenous in 19%, and the inferior vena cava in 2%; multisegment involvement was common. (3) Total occlusion was present in 82% of the patients with deep vein thrombosis, and partial occlusion in 18%. (4) Isolated occlusion of single veins was uncommon. (5) The proximal (above-knee) area was involved in 95% of the cases with deep vein thrombosis, and the calf in 40% of the cases. Isolated calf deep vein thrombosis was found in 6% of the cases with right leg involvement and in 3% for the left. (6) Total leg involvement (iliocaval, femoropopliteal, and calf) occurred in 10% of the patients. Our data confirm the fallibility of the clinical diagnosis of deep vein thrombosis. The frequent involvement of both limbs stresses the importance of not examining just the symptomatic limb. Proximal venous thrombosis (popliteal to inferior vena cava) is much more common than isolated calf vein thrombosis as a cause for symptoms and the referral for study.

Valvular reflux after deep vein thrombosis: incidence and time of occurrence.

From December 1986 to December 1990, 268 patients with acute deep vein thrombosis were studied in our laboratory. From this group 107 patients (123 legs with deep vein thrombosis) were placed in our long-term follow-up program. The documentation of valvular reflux and its site was demonstrated by duplex scanning. The duplex studies were done at intervals of 1 and 7 days, 1 month, every 3 months for the first year, and then yearly thereafter. The mean follow-up time for these patients was 341 days. In addition, reflux was evaluated in 502 patients with negative duplex study results and no previous history of deep vein thrombosis or chronic venous insufficiency. In the patients with acute deep vein thrombosis, valvular incompetence was noted in 17 limbs (14%) at the time of the initial study. Reflux was absent in 106 limbs (86%). In this last group reflux developed in 17% of the limbs by day 7. By the end of the first month, 37% demonstrated reflux. By the end of the first year, more than two thirds of the involved limbs had developed valvular incompetence. The distribution of reflux at the end of the first year of follow-up was the following: (1) popliteal vein, 58%; (2) superficial femoral vein, 37%; (3) greater saphenous vein, 25%; and (4) posterior tibial vein, 18%. Reflux seems to be more frequent in the segments previously affected with deep vein thrombosis. Among cases where segments were initially affected with thrombi, after 1 year the incidence of reflux was 53%, 44%, 59%, and 33% for the common femoral vein, superficial femoral, popliteal vein, and posterior tibial vein, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)