Background:
Ultrasound-assisted-catheter-directed thrombolysis using the EkoSonic Endovascular System (EKOS) is an established treatment for intermediate high-risk (IHR) pulmonary embolism (PE). Although IHR-PE is at risk of hemodynamic compromise, the current European guidelines do not specify an optimal timing for EKOS therapy. Early unloading of the right ventricle (RV) may be crucial. This study evaluates differences in safety and efficacy between early (<12hours (h)) and delayed (>12h) intervention.
Methods:
We performed a retrospective multicenter study including patients with IHR-PE treated with EKOS at the University Heart Centre Lübeck, Schön Clinic Neustadt and Friedrich-Ebert-Hospital Neumünster. Patients were divided into two groups by EKOS-timing relative to the CT-confirmed diagnosis. Hereby, one group received treatment within 12h, and the other after 12h. Right and left ventricular function were assessed by transthoracic echocardiography including RV to left ventricular (RV/LV) ratio, tricuspid annular plane systolic excursion (TAPSE), and RV end diastolic diameter (RVEDD). Secondary outcomes included duration of intensive care unit (ICU) stay, complications, and mortality. Follow-up after three months was performed at University Heart Centre Lübeck and Schön Clinic Neustadt.
Results:
We included 152 patients, 106 patients received EKOS-Lysis within 12h and 46 patients after 12h. Patients in the early group suffered significantly more commonly from dyspnea NYHA class II and III (II: 4.7% vs. 23.9%, p<0.001; III: 72.6% vs. 45.7%, p=0.001). The other baseline characteristics were comparable between groups. Left ventricular ejection fraction (LVEF) measured before performing EKOS was slightly lower in the delayed group (58±8% vs. 54±6%, p=0.003). Both groups showed significant LVEF improvement (p<0.001) with a numerically greater change in the early group (2.0±4.5% vs. 0.97±3.4%, p=0.426). RV/LV ratio, TAPSE, and systolic pulmonary artery pressure (sPAP) improved significantly in both groups (p<0.001 each). The magnitude of improvement favored early treatment although differences were not statistically significant (ΔRV/LV −0.35±0.29 vs. −0.28±0.26, p=0.318; ΔTAPSE 4.9±5 mm vs. 3.5±5mm, p=0.249; ΔsPAP −14.4±13mmHg vs. −12.2±9mmHg, p=0.255). At follow-up, the magnitude of improvement was almost identical (ΔRV/LV −0.46±0.28 vs. −0.45±0.29, p=0.738; ΔsPAP −20.5±9.5mmHg vs. −20.7±9.5mmHg, p=0.952). Early treatment resulted in a significantly shorter ICU stay (34.5±29h vs. 46.6±35h, p=0.033). Complication rates (13.2% vs. 19.6%, p=0.32) and bleeding events (12.3% vs. 17.4%, p=0.4) did not differ significantly between groups, although there was a trend to more gastrointestinal bleedings in the delayed group (6.5% vs. 0.9%, p=0.083). In-hospital mortality was almost the same (6.6% vs. 6.5%, p=1).
Conclusion:
In IHR-PE, EKOS within 12h after CT diagnosis is associated with more pronounced RV recovery and a significantly shorter ICU stay compared with delayed therapy. These findings support early EKOS pathways to optimize outcomes in acute PE. Prospective studies are needed to confirm these results.
