Thrombus resolution
The main outcome evaluated in our patient cohort was complete thrombus resolution (without residual thrombosis) following treatment. Follow up imaging performed at 6 months (for those patients who did not have repeat imaging performed at 6 months, the most recent image prior to 6 months was collected) revealed complete thrombus resolution in 34.5% (n=10) of patients. Of the 19 patients that did not have complete resolution, 47.4% (n=9) had residual complete occlusion and 52.6% (n=10) had residual partial occlusion noted. The last dedicated venous imaging performed was under 6 months in 62.1% (n=18) of the cases. In patients who had serial imaging beyond 6 months, no change in the thrombus burden was noted when compared to earlier time points. The range of final follow up images available was 0.5 to 15 months (median 4 months). There were three patients that transferred care to another institution (due to closer proximity to their homes) whose last available follow up image was less than 2 months following DVT diagnosis and intervention with residual thrombosis present. Doppler ultrasonography was the imaging modality for 96.6% (n=28) of final follow up images; one patient had venography as the modality of final follow up image. Overall, non-Hispanic patients (60% white, 20% each African American or Asian) had a trend for higher rate of thrombus resolution (45.5%, n=10) compared to those of Hispanic ethnicity (all white) who had no cases of thrombus resolution (p=0.06).
Patients that received bolus tPA “on-table” alone had resolution in 57.1% (n=4) while those that received CDT had resolution in 27.3% (n=6, p=0.19 fisher exact test).
Patients that received thrombolysis via Angiojet had a higher rate of thrombus resolution compared to those that did not receive Angiojet thrombolysis, 62.5% vs 23.8%, respectively, although this difference did not reach statistical significance in our sample (p=0.08). There was no difference in thrombus resolution noted when comparing those patients who underwent intravascular stent placement and those who did not.
Patients that received rivaroxaban as an anticoagulant had a higher rate of thrombus resolution compared to those who did not, 75% vs 19% (OR=12.75, 95% CI=2.10-114.33; p = 0.009). This relation remained significant after control for potential confounding influence of ethnicity (adjusted OR=7.5; 95% CI=1.17-69.21; p=0.045). Other anticoagulants used (unfractionated heparin [UFH], low molecular weight heparin [LMWH], warfarin, and bivalirudin) were not associated with thrombus resolution.
Furthermore, the risk factor of hormonal therapy use was associated with thrombus resolution, as those taking estrogen-containing hormonal therapy prior to diagnosis experienced thrombus resolution in 83.3% (n=5) of cases, while those not on hormonal therapy had thrombus resolution 21.7% (n=5) of the time (p=0.01). No other risk factor studied was associated with thrombus resolution (see Table 3 ).