Role of catheter-based interventions in treating pulmonary embolism

Table 1 Simplified risk stratification for acute pulmonary embolism adapted from the 2019 European Society of Cardiology guidelines

Risk level	Key features	Prevalence in pulmonary embolism cases	Estimated 30-day mortality
HR	Indicators of severe circulatory compromise: Cardiac arrest; obstructive shock (systolic BP < 90 mmHg with organ damage); sustained low BP (< 90 mmHg or drop ≥ 40 mmHg for > 15 minutes) not due to arrhythmia/sepsis; high lactate levels (≥ 2 mmol/L)	5%–10%	30%–55%
Intermediate-high	Signs of RV strain and cardiac injury: RV/LV diameter ratio ≥ 1; TAPSE ≤ 16 mm; PESI class III–V or sPESI ≥ 1; elevated troponin or BNP	15%–20%	10%–15%
Intermediate-low	Presence of either: RV dysfunction (RV/LV ratio ≥ 1, TAPSE ≤ 16 mm, PESI III–V or sPESI ≥ 1); elevated cardiac biomarkers (troponin, BNP)	30%–40%	5%–15%
Low risk	Does not meet any of the above intermediate or HR criteria	30%–40%	< 3%

BNP: B-type Natriuretic Peptide; BP: Blood pressure; HR: High-risk; PESI: Pulmonary Embolism Severity Index; RV: Right ventricular; RV/LV: Right ventricular-to-left ventricle; TAPSE: Tricuspid Annular Plane Systolic Excursion; SPESI: Simplified Pulmonary Embolism Severity Index.

Table 2 Catheter-based interventions for pulmonary embolism

Therapy type	Key devices	Mechanism of action	Evidence and trials	Benefits	Complications/risks
CDT	Standard/perforated infusion catheters (Uni-Fuse, Cragg-McNamara)	Local thrombolytic drug infusion into thrombus	Supported by ULTIMA, SEATTLE II, OPTALYSE PE	Lower bleeding risk than systemic thrombolysis	Requires prolonged infusion, potential bleeding
Ultrasound-assisted thrombolysis	EKOS (EkoSonic)	Ultrasound energy enhances thrombolytic penetration	Same trials as CDT, plus KNOCOUT PE, SUNSET sPE	Effective RV-to-left ventricle ratio reduction, low bleeding	Variable efficacy vs standard catheter-directed thrombolysis, longer duration
Mechanical thrombectomy-FlowTriever	FlowTriever (Inari)	Aspiration with large-bore catheters and clot disruption tip	FLARE, FLASH registry	Immediate hemodynamic improvement, low mortality	Blood loss, procedural complexity
Mechanical thrombectomy-Indigo	Indigo system (Penumbra)	Automated aspiration using suction pump and separator wire	EXTRACT-PE, STRIKE-PE	Rapid improvement in RV strain, symptom relief	Device-related events (rare), training required
Pharmaco-mechanical thrombectomy	Combined use of thrombolytics and mechanical devices	Dual action: Clot lysis and mechanical removal	PEERLESS Trial	Improved outcomes over thrombolysis in some studies	Need for precise patient selection, limited long-term data

CDT: Catheter-directed therapy; RV: Right ventricular.