Efthymios Avgerinos (University of Pittsburgh, Pittsburgh, USA) presented results from the SUNSET sPE trial during a late-breaking data session at this year’s Vascular Interventional Advances conference (VIVA 2020; 6–8 November, virtual). His concluded that catheter thrombolysis is safe and effective in tertiary expert centres and can achieve quick thrombus and right to left ventricular (RV/LV) ratio reduction, and that ultrasound-assisted thrombolysis may not confer additional benefits to standard catheter thrombolytic techniques.
The SUNSET sPE trial is a multicentre randomised trial that investigated whether ultrasound-assisted (USAT) is superior to standard-catheter (SCDT) thrombolysis in pulmonary arterial thrombus reduction.
Adults with sPE were randomised 1:1 to a USAT catheter (EKOS system, BTG) or a SCDT catheter. Thrombolysis dose and duration were left to the operators’ discretion. The primary outcome was 48-hour clearance of pulmonary thrombus assessed by pre- and post-procedure computed tomography angiography (CTA) using a refined Miller score. Secondary outcomes included RV/LV ratio improvement, intensive care unit (ICU), bleeding, and other serious adverse events.
Eighty-one patients with acute sPE were randomised and were available for analysis. The mean total dose of alteplase for USAT was 19±7mg and 18±7mg in SCDT (p=0.53) infused over 14±6 hours and 14±5 hours, respectively (p=0.99).
Addressing the VIVA audience, Avgerinos reported that in the USAT group (n=39), the mean raw pulmonary thrombus score was reduced from 31±4 at baseline to 22±7 (p<0.001). In the SCDT group (n=41), the score was reduced from 33±4 to 23±7 (p<0.001). There was no significant difference in mean thrombus score reduction between the two groups (p=0.76), and the obstruction index reduction was also similar between groups: 21% and 22% for USAT and SCDT, respectively (p=0.77). The mean difference in RV/LV ratio from baseline (1.54±0.30 for USAT, 1.69±.44 for SCDT) to 48 hours was 0.37±0.34 in USAT vs. 0.59±0.42 in SCDT (p=0.01). In five USAT and three SCDT patients there was no RV/LV ratio improvement.
He added that major bleeding (one stroke with hemianopia and one vaginal bleed requiring transfusion) occurred in two patients both in the USAT group. The average ICU stay for the entire cohort was 3.2±6.3, similar between groups.
Avgerinos summarised that in the SUNSET sPE trial, patients undergoing USAT had similar pulmonary arterial thrombus reduction compared to SCDT, using comparable mean lytic dose and duration of lysis.