Ultrasound‑enhanced, catheter‑directed thrombolysis for pulmonary embolism

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 retrospective comparative case series of 25 patients with acute massive pulmonary embolism (PE) compared ultrasound‑enhanced, catheter‑directed thrombolysis (UE‑CDT; n=11) against catheter-directed thrombolysis alone (CDT; n=14). It reported a significant difference between the 2 groups in the rate of complete thrombolysis (>90% removal) at angiography assessment performed 12–48 hours after the start of treatment (UE‑CDT 100% [11/11] and CDT 50% [7/14]; p=0.01). The study also reported that there was a significant difference in the mean overall infusion time between the 2 treatment groups (UE‑CDT group 17.4±5.23 hours, CDT group 26.7±8.64 hours; p=0.03).

4.2 In a systematic review of 7 studies (n=197), 3 studies assessed the right‑to‑left ventricular dimension (RV/LV) ratio using a chest CT scan or echocardiography, before and after UE‑CDT. The pooled mean RV/LV ratio decreased from 1.36 to 1.03 (no significance test was reported).

4.3 In the systematic review of 7 studies, 3 studies reported mean pulmonary artery pressure before and after UE‑CDT. The pooled mean pulmonary artery pressure decreased from 31.3±9.0 mmHg before treatment to 22.7±6.9 mmHg after treatment (no significance test was reported).

4.4 In the systematic review of 7 studies, 2 studies reported cardiac index before and after UE‑CDT. The pooled mean cardiac index increased from 2.2±0.7 l/min/m² before treatment to 3.1±1.3 l/min/m² after treatment (no significance test was reported).

4.5 In the systematic review of 7 studies, 4 studies assessed pulmonary thrombus load before and after UE‑CDT using various angiographic scores (Miller index, modified Miller score, and Mastora score). The pooled mean relative reduction in the pulmonary occlusion score was 41% (scores ranged from 32% to 69%; no significance test was reported).

4.6 In the systematic review of 7 studies, 2 studies reported recurrence of PE in 2 patients at follow‑up. A suspected recurrent PE 1 day after UE‑CDT was reported in a case series of 24 patients. This was treated with rescue thrombolysis (100 mg rtPA) given intravenously over 2 hours. A recurrent PE 4 months after thrombolysis, from non‑compliance with anticoagulant treatment, was reported in a case series of 10 patients. This patient died of severe right ventricular failure.

4.7 A retrospective case series of 22 patients with a sub‑massive or massive PE who had UE‑CDT reported that 86% (19/22) of patients were alive at 180 day follow‑up.

4.8 The specialist advisers listed additional efficacy outcomes as long‑term reduction in pulmonary hypertension and right ventricle dysfunction, reduction in right ventricle strain, shortened recovery time and hospital stay, symptom relief and vessel patency.