Ultrasound‑enhanced, catheter‑directed thrombolysis for deep vein thrombosis

4 Efficacy

This section describes efficacy outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.

4.1 A randomised controlled trial (RCT) of 48 patients with acute iliofemoral deep vein thrombosis (DVT) comparing ultrasound‑enhanced catheter‑directed thrombolysis (UE‑CDT; n=24) against catheter‑directed thrombolysis (CDT; n=24), with a fixed dose thrombolysis regimen in all patients, reported that there was no significant difference in the percentage of thrombus load reduction from baseline to 15 hours after treatment (according to Length‑Adjusted Thrombus score, obtained from venograms) between the 2 treatment groups (UE‑CDT 55±27% and standard CDT 54±27%; p=0.91).

4.2 A retrospective comparative case series of 83 patients with DVT comparing UE‑CDT (n=64) against CDT alone (n=19) reported no significant difference between the 2 groups in the rate of substantial thrombolysis (>50% removal) at the last angiography assessment at a median follow‑up of 26 hours (UE‑CDT 89.1% [57/64] and CDT 89.5% [17/19]; p=0.96). The study also reported that there was no significant difference in overall infusion time between the 2 treatment groups (UE‑CDT 27 hours [range 21–27], CDT 25 hours [range 22–39]; p=0.39).

4.3 A retrospective comparative case series of 178 patients with DVT comparing UE‑CDT (n=46) against pharmacomechanical thrombectomy (PMT) (n=84) and against PMT plus UE‑CDT (n=27) reported that in patients with chronic DVT (n=62), the combined intervention achieved complete treatment success (defined as complete thrombus removal based on angiographic evidence) more frequently (74% [20/27]) than either UE‑CDT or PMT alone (64% [9/14] and 33% [7/21] respectively; p values not reported). Complete treatment success was similar in patients with acute DVT (n=116) who had UE‑CDT or PMT alone (88% [28/32] and 82% [69/84] respectively).

4.4 A retrospective comparative case series of 47 patients with 53 occlusive DVTs comparing UE‑CDT against historical controls who had CDT alone (n=82) reported that median total dose of each thrombolytic drug was lower in UE‑CDT compared with CDT alone (respectively, urokinase 2.0×10^ounits and 4.4×10^ounits; tissue plasminogen activator 14 mg and 21.6 mg; recombinant plasminogen activator 6.9 units and 21.4 units).

4.5 The retrospective comparative case series of 178 patients with acute and chronic DVT comparing UE‑CDT against PMT alone and combined UE‑CDT plus PMT reported that in patients with chronic DVT (n=62) immediate clinical improvement occurred more often in the UE‑CDT and combined intervention group (64% [9/14] and 63% [17/27] respectively) compared against PMT alone (28% [6/21], p values not reported).

4.6 A case series of 12 patients who underwent UE‑CDT reported that recurrent DVT needing treatment occurred in 46% (6/13) of occlusions at a mean follow‑up of 7 months.

4.7 The RCT of 48 patients with acute iliofemoral DVT comparing UE‑CDT against standard CDT reported no significant difference in the severity of post‑thrombotic syndrome, measured by mean Villalta score, between the 2 treatment groups (UE‑CDT 3.0±3.9 and standard CDT1.9±1.9; p=0.21), at 3‑month follow‑up. A case series of 26 patients who underwent UE‑CDT reported mild post‑thrombotic syndrome in 11.5% (3/26) of patients: this mainly manifested as pain, heaviness and oedema of the affected limbs after activity. The median post‑thrombotic syndrome score in these patients was 2 (range 0–7).

4.8 The specialist advisers listed efficacy outcomes as duration of thrombolysis ('enhanced' thrombolysis over a shorter period of time), dose of thrombolytic drug, recanalisation of deep veins ('resolution of thrombus'), DVT symptom relief, prevention of long term sequelae of DVT (that is, freedom from post‑thrombotic syndrome), recurrent DVT, long‑term vessel patency and quality of life.