Venous
Procedure Guide
Indications
High-risk (“massive”) PE, though some guidelines suggest trial of anticoagulation and systemic tPA and catheter-directed therapy (CDT) only for failure or contraindication to systemic tPA.
Intermediate-high risk PE - guidelines vary often saying CDT should be considered. Similar to above, some guidelines recommend an initial trial of anticoagulation with systemic tPA and consideration of CDT if deterioration or failure to improve with anticoagulation.
Risk stratification:
High-risk (“massive”) = PE with hemodynamic instability, primarily hypotension.
Intermediate-high risk (“submassive”) = Hemodynamically stable PE with clinical signs of PE severity (PESI class III-IV or sPESI >1) OR evidence of RV dysfunction on TTE or CTA (RV:LV >1, TAPSE <=16 mm, congested IVC) with ELEVATED cardiac troponins.
Intermediate-low risk (“submassive”) = Hemodynamically stable PE with clinical signs of PE severity OR evidence of RV dysfunction but NEGATIVE elevated cardiac troponins.
Low-risk = Hemodynamically stable PE without clinical signs of PE severity OR evidence of RV dysfunction.
Indicators of severity of PE in normotensive patients:
Clinical: HR >100, BP 90-100 mHg, RR >20, Sao2 <90%, h/o chronic heart failure or active neoplasm
Imaging: RV:LV >1, TAPSE <=16 mm, congested IVC
Labs: elevated cardiac troponin, NT-proBNP >600 pg/mL, lactate >2 mmol/L
FLASH Composite PE Shock Score
Estimates risk of normotensive shock and future deterioration.
One point each for elevated troponin, BNP, mod/severe RV dysfunction on echo, saddle PE, DVT, and tachycardia
Predictors of adverse events:
Large clot burden: 17x mortality risk at 6 months
Central clot distribution: >2x PE related mortality
Concomitant DVT: >4x risk of PE- related mortality and recurrent VTE at 90d
ESC Working Group
Contraindications
Inability to tolerate anticoagulation
For fibrinolysis (t-PA):
Absolute
History of hemorrhagic stroke or stroke of unknown etiology
Ischemic stroke within 6 mo
CNS neoplasm
Major trauma, surgery, or head injury within 3 wks
Bleeding diathesis
Active bleeding
Relative
TIA within 6 mo
Oral anticoagulation
Pregnancy or first week postpartum
Noncompressible puncture sites
Traumatic resuscitation
Use of ECMO
Advanced liver disease
Infective endocarditis
Active peptic ulcer
Refractory hypertension (SBP >180 mHg)
Efficacy and alternatives
Systemic thrombolysis: superior to anticoagulation alone for submissive PE (PEITHO, TOPCOAT, and MOPETT trials), but higher risk of major hemorrhage (9-20%)
Important CDT Trials:
ULTIMA: only RCT to date showing CDT improves RV:LV at 24 hrs more than anticoagulation alone for submissive PE.
SEATTLE II: CDT improves RV:LV on CT at 48 hrs and PA pressure for submassive/massive but 11% bleeding risk (no ICH).
PERFECT: CDT achieved clinical success for 86% massive and 97% submissive PE without major complications. Pressure reduction consistent across trials.
Optalyse: No difference in RV:LV reduction at 48 hrs across 4 different lysis lengths and doses but higher doses of t-PA cleared more thrombus. Major weakness was no control arm, unclear if similar results occur without intervention.
SUNSET sPE: No benefit of ultrasound with lysis (EKOS) vs standard therapy.
FLAME Registry: 1.9% vs 64% in-hospital mortality and 17% vs 64% major adverse event rate using FlowTriever (Inari) for massive PE.
FLASH Registry: major adverse events in 1.8% (11/14 were major bleeds); all cause mortality 0.3%, 0.8%, and 5.0% at 48hrs, 30d, and 6mo; 6.2% 30d readmission using FlowTriever (Inari) for acute PE.
PERT Database: 30d all cause mortality 10.2%, 30d readmission 24.4%.
EXTRACT PE: mean RV/LV reduction 0.43, 3 major adverse events in 2 pts (1.7%), no intraprocedural thrombolytic drug use in 98.3% using Indigo aspiration system (Penumbra) for submissive acute PE
STRIKE PE: MT using Lightning 12 (Penumbra) in patients with acute PE and RV/LV >0.9. Mean RV/LV reduction 26%, mean PAP reduction 5.8 mmHg (17.1%), EBL 286 mL, MAE 2.7%, and significant improvement in QoL and dyspnea scores at 90d.
KNOCOUT Registry: US-facilitated thrombolysis for 489 patients with high risk or intermediate high risk PE. Mean t-PA dose 18 mg, procedure time 40 min, major bleeding 1.6%, no intracranial hemorrhage
RESCUE trial: lysis/thrombectomy with Bashir catheter, mean reduction in RV:LV 33% and obstruction index 36% at 48 hrs, median placement time 15 min, major bleeding within 72 hrs 0.9%, median hospital LOS 2.8 days
RiHTER Registry: 30d mortality associated with hemodynamics of PE not presence/characteristics of right heart thrombus. However, right heart thrombus associated with higher mortality and deterioration with 62% death in first 24 hrs.
Overview of evidence for interventions to treat PE from the AHA
Pre-procedure care
Should on therapeutic anticoagulation. Some data suggests enoxaparin is superior to unfractionated heparin.
Risk stratification as described above. Ideally with a multidisciplinary discussion, which can be facilitated by establishment of a PERT (Pulmonary Embolism Response Team).
Coordinate having anesthesia present or available for backup. Also helpful to alert ECMO team in case they are needed, particularly for massive PEs where available.
Ideal to have light/moderate sedation if possible. If deeper sedation is necessary, propofol should be avoided as studies suggest increased risk of rapid right heart failure and death, particularly during induction.
Procedures
Central venous access (often common femoral vein or internal jugular)
CFV better if planning for large bore central thrombectomy.
RIJ if needed or for lysis.
Often need long sheath with size depending on planned intervention and access, e.g, device specific for thrombectomy. For lysis, 7 Fr 35-45 cm sheath and/or 5 Fr 10 cm sheath can work well. If using IJ access, may need a curved sheath such as a Flexor Balkin (Cook).
RIJ if needed or for lysis, 7F 35-45 cm sheath and/or 5F 10 cm sheath
Catheterize the pulmonary artery (PA) - classic teaching is to use a Grollman, pigtail with curved backend of a wire to create a Grollman, Van Aman Berman, or balloon catheter to avoid traversing trabeculae that could then be damaged when advancing a larger device/sheath.
If ventricular tachycardia, change wire/catheter positioning. If sustained, 150 mg amiodarone or cardioversion.
If trouble catheterizing the MPA, consider angiogram with 10 mL in 20-30* RAO to outline RV and MPA. Also help identify if one has inadvertently passed through a PFO into the LA.
(Optional) Pressure measurements in right ventricle and PA.
(Optional) Pulmonary angiogram with nonionic low osmolality contrast in single pulmonary artery at a time
Flow rates: 15-20 ml/s for 30-40 ml or 10-15 ml/s for 20-30 ml for higher pressures).
Some avoid due to risk of further elevating the right heart pressures risking deterioration.
Once in PA, advance stiffer working wire (e.g. Rosen).
Advance sheath.
Thrombolysis - should be 2 Fr larger than infusion catheter to enable pressure monitoring via sheath side port, e.g., 7 or 8 Fr Flexor sheath with 5 Fr Unifuse. If using IJ access, may need a curved sheath such as a Flexor Balkin (Cook).
Thrombectomy - sizing depends on specific device being used.
Pass wire through thrombus to treat, ideally nonhydrophilic wire but hydrophilic can be used with caution to not perforate or dissect the vessels.
Good combo are exchange length Rosen with 100 cm Berenstein or Kumpe then switch for Amplatz once in place.
Thrombectomy and/or thrombolysis: some use thrombectomy for larger central clot burden vs thrombolysis for predominantly peripheral clot burden
Thrombolysis:
Advance infusion catheter (e.g. Unifuse, Cregg-McNamara, Fountain infusion system, EkoSonic) over a wire into dominent clot burden, often bilateral lower lobes.
Start tPA infusion (0.5-1 mg/hr per catheter + supratherapeutic AC via sheath for 6-12 hrs)
Thrombectomy: multiple devices (see below), can also just use a pigtail catheter to breakup the clot (old school)
Maintain ACT ~250
Right heart thrombus tends to be large (>5cm) and snake-like so requires larger device.
Can still do thrombolysis at end for residual clot burden.
Example devices below:
FlowTreiver (Inari) - aspiration via 16-24F catheter, nitinol discs can be used to pull clot into aspiration catheter, can aspirated blood back
Lightning 7 and 12 and Flash systems (Penumbra) - computer-aided mechanical aspiration and fragmentation to help reduce blood loss, range of smaller, lower profile catheter sizes (8-16F)
AngioVac - requires perfusionist with V-V-ECMO, 26F funnel-shaped tip inflow for aspiration, 16-20F outflow
Aspirex (BD) - mechanical and suction thrombectomy via 6-8F catheters
BASHIR catheter (Thrombolex) - mechanical fragmentation and thrombolytic infusion via expandable nitinol infusion basket, comes in 7F (0.018”) and 8F (0.035”) versions
JETi (Abbot) - hydrodynamic aspiration thrombectomy with fragmentation, lower profile 6-8F catheters
AlphaVac - large bore (22-26F access) with expandable funnel and manual suction, APEX-AV trial demonstrated safety and efficacy
Magneto eTrieve PE Kit - voltage applied to catheter leading to embolus binding the electrode
Helo Thrombectomy System - lower profile catheter with self expanding funnel for large bore performance, ENGULF trial demonstrated safety and feasibility
(Optional) IVC filter placement. Debated though some consider in the setting of high risk PE with large residual proximal deep venous thrombosis clot burden.
Achieve hemostasis.
Complications
Major bleeding ~4.3% across trials, potentially less with thrombectomy, e.g., Inari trials report 1-2%
Intracranial hemorrhage ~0.7% across trials
Right heart failure and death (<1%), worse with massive PE, poor reserve, contrast injections, propofol
Damage structures along the way, e.g., puncture of pulmonary artery, heart valve damage with larger devices
Bradyarrhythmia with AngioJet, hence the blackbox warning
Post-procedure care and follow up
Often requires ICU monitoring after though some with good thrombectomy result can go to a lower level of care pending institutional policies.
For thrombolysis:
Often requires ICU monitoring with CBC +/- fibrinogen every 4-6 hrs during the infusion to reduce or stop infusion if fibrinogen falls below 150-200. Some adjust the sheath side arm anticoagulation infusion to subtherapeutic to reduce bleeding risk (e.g. 500 IU/hr UFH).
Catheters and sheath can be removed at bedside several minute after stopping tPA. May need hemostatic dressing (e.g. D-Stat). Can resume full dose anticoagulation 15 minutes post hemostasis.
Continue anticoagulation often in collaboration with hematology consultation.
Repeat echo within 48 hours to assess for resolution of right heart strain
Follow up in clinic in 1-3 months. Can repeat echo and monitor for CTEPH.