OBJECTIVE

To assess the effect of the adequacy of anticoagulant therapy (ACT) on the risk of pulmonary embolism (PE) in patients with proximal deep vein thrombosis.

MATERIAL AND METHODS

The analysis of a database consisting of 223 patients with proximal venous thrombosis (the thrombus location was not lower than the superficial femoral vein) was carried out. The types of detected ACT flaws and their frequency were analyzed. The role of ACT flaws in episodes of bleeding, thrombosis progression, PE, and deaths was evaluated.

RESULTS

Of the 223 patients, there were 97 women (43.5%) and 126 men (56.5%). The mean age was 63.4±16.2 years, the average hospital stay was 6.8±2.7 days. Flaws in the ACT were found in 36.3% (81 people) of cases. Among the identified flaws were: an increase in activated partial thromboplastin time (aPTT) by more than 2.5 times — 12 (5.4%) patients, lack of aPTT control in the first 3 days with unfractionated heparin (UFH) therapy — 40 people (17.9%), lack of achievement of target aPTT values in the first 3 days with UFH therapy — 20 people (13%), therapy with a reduced dose of rivaroxaban 20 mg / day in the acute phase of thrombosis without indications for dose reduction — 2 people (1.3%). 2 episodes of symptomatic PE have been recorded. In the first case, there were no ACT flaws, in the second, clinical manifestations of PE occurred in a patient receiving UFH with aPTT values equal to 26—27 seconds. There were no deaths and bleedings. In 40 patients (17.9%), an increase in the level of thrombosis was recorded against the background of ACT. The results of the logistic regression analysis showed that a statistically significant factor in increasing the level of thrombosis is the start of an act with UFH — the odds ratio is 2.52 (95% CI: 1.11—5.74) (p=0.0271).

CONCLUSION

Most often, ACT flaws occur when UFH is prescribed due to its poorly predictable pharmacokinetics and the need for laboratory monitoring. Even though the performed ACT often has defects, it is still able to prevent the progression of VTE in most cases. Even an adequate ACT is not guaranteed to prevent an embolism.