Venous thrombus stability during acute phase of therapy

Posttreatment ultrasound-detected residual venous thrombosis: a risk factor for recurrent venous thromboembolism and mortality

PURPOSE OF REVIEW

The cumulative risk of recurrent venous thrombosis may rise to 30% over 8 years. Extended oral anticoagulation is effective but major bleeding is increased. To balance these risks attention has focused on identifying patients with the highest likelihood of recurrence for whom continued therapy is most beneficial. Another issue of interest has been the increased probability of death after venous thrombosis, due primarily to malignancy but also to vascular disease.

RECENT FINDINGS

Unprovoked events and cancer are known to be associated with recurrent thrombosis. Residual posttreatment thrombosis confirmed by compression ultrasound is regarded as another risk for recurrence. Confounders in the published studies are the patient mix and the ultrasound technique employed. Other variables such as gender and D-dimer may also predict risk. Although arterial disease is increased in patients with venous thromboses, the association between idiopathic venous thromboembolism and atherosclerosis remains circumstantial.

SUMMARY

There are no validated approaches for predicting recurrent venous events. Ultrasound interrogation for residual thrombosis after primary therapy may improve treatment stratification by defining patients suitable for extended anticoagulation.

Calf deep venous thrombosis should be treated with anticoagulation

A 50-year-old man with hypertension presents with a 2-day history of right calf swelling and pain. Venous duplex ultrasound reveals a right soleal vein thrombosis. He denies history of bleeding, renal disease, and symptoms suggestive of pulmonary embolism (PE). Physical examination is unrevealing except for calf tenderness, redness, warmth, and swelling. He is ambulatory. A decision is made to treat the calf deep venous thrombosis (DVT) with anticoagulation.

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.

Evolution of deep venous thrombosis: a 2-year follow-up using duplex ultrasound scan and strain-gauge plethysmography

OBJECTIVE

The development of the post-thrombotic syndrome (PTS) and recurrence of deep venous thrombosis (DVT) are not yet fully understood. The aim of the study was to identify factors that lead to the long-term complications of DVT.

METHODS

In a 2-year prospective follow-up study, duplex scanning and strain-gauge plethysmography were used to evaluate DVT in relation to the development of long-term complications. Each of the 12 segments examined was assigned as a thrombosis score (TS). A total TS was calculated for each leg. Patent segments were assigned a TS = 0, noncompressible vein segments with flow TS = 1 and noncompressible vein segments without flow TS = 2. The degree of resolution of DVT and the incidence, timing, and outcome of further thrombotic events were measured during 24 months of follow-up.

RESULTS

The study involved 86 legs with DVT. The 2-year follow-up was completed for 70 legs. Within 3 months, only 1% of the originally occluded proximal deep vein segments were still occluded. Between all time intervals, from month 12 to month 24, for example, thrombus regression continued in 36% of the legs and thrombus propagation continued in 27%. Multiple regression analysis revealed that an increase in age (P = .008) and proximal location of the original DVT (P = .05) was significantly related to thrombus propagation. Multiple regression analysis showed that the risk factors for clinical signs of PTS were a high venous outflow resistance after 1-month and 12-month follow-ups (P <or= .002) and a high thrombosis score in the proximal veins after 3 months (P = .008).

CONCLUSIONS

In the follow-up of older patients and patients with proximal DVT, evolution was shown to be an unstable process with continuing propagation for 2 years. The risk factors for the development of PTS were a slow decrease in venous outflow resistance or a high thrombosis score of the proximal veins after 3 months.

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.