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SIR position statement on CDT

SIR position statement on CDT for acute pulmonary embolism

• The SIR supports the use of CDT in carefully selected patients with proximal acute massive PE, especially in highly-compromised or rapidly-deteriorating PE patients who have failed systemic thrombolysis
• The SIR strongly supports the conduct of new RCTs and other prospective studies on the use of CDT for acute PE, in particular for submassive PE, with a focus on studying long-term outcomes and possible prevention of PPS and CTEPH

The Society of Interventional Radiology (SIR) has issued a position statement on catheter-directed therapy (CDT) for acute pulmonary embolism (PE), which stats that the society deems the use of CDT or thrombolysis to be an acceptable treatment option for carefully selected patients with massive (ie, high risk) PE involving the proximal pulmonary arterial vasculature, in accordance with multidisciplinary guidelines. The position paper, ‘Society of Interventional Radiology Position Statement on Catheter-Directed Therapy for Acute Pulmonary Embolism’, was published by Dr William T Kuo et al in the Journal of Vascular and Interventional Radiology.

Acute proximal PE is defined as new main or lobar emboli identified on radiographic imaging within 14 days of PE symptoms. In addition, SIR encourages the investigative use of CDT and new endovascular techniques in prospective outcomes studies and clinical trials, with particular attention to patients with acute submassive (ie, intermediate risk) PE.

Acute massive PE

The paper notes that systemic thrombolysis is currently indicated for the treatment of acute massive PE, however many patients cannot receive systemic thrombolytic therapy because of contraindications - and even when patients with acute PE are pre-screened for absolute contraindications - the rate of major haemorrhage associated with systemic thrombolysis has been estimated at 9.2%, with a 1.5% risk of intracranial haemorrhage.

According to the paper, a meta-analysis of RCTs and observational studies have shown that these bleeding risks may be higher among real-world populations. One possible advantages of CDT could include the ability to use a lower thrombolytic drug dose and obtain faster lysis as a result of the targeted intrathrombus drug delivery and the addition of mechanical treatment (ie, pharmacomechanical CDT).

Submassive PE

For patients with submassive PE, a recent meta-analysis of randomised trials revealed a much higher risk of major bleeding complications, compared with anticoagulation alone. Therefore, the paper states, the risk-to-benefit ratio of systemic thrombolysis in the submassive PE population is uncertain with regard to clinical decision-making. A potential advantage with CDT is targeted drug delivery into the clot to achieve low-dose thrombolysis, which may reduce bleeding risk, Therefore, the paper states that relative to systemic drug therapy, local CDT may improve drug effectiveness, allow a lower drug dose to be used, and result in fewer bleeding complications.

However, the evidence is still limited and a research consensus panel (sponsored by the SIR Foundation) discussed key questions and data gaps surrounding submassive PE. The research consensus panel concluded that a randomised trial of CDT vs. anticoagulation alone is a primary research priority to determine if early use of CDT can reduce the long-term risk of post–pulmonary embolism syndrome (PPS) and chronic thromboembolic pulmonary hypertension (CTEPH).

In summary the paper concludes:

  • The SIR supports the use of CDT in carefully selected patients with proximal acute massive PE, especially in highly-compromised or rapidly-deteriorating PE patients who have failed systemic thrombolysis.
  • There is insufficient to support the routine use of CDT for patients with submassive PE. Although CDT may have advantages over other modalities for specific patients, in centres that use CDT for treatment of submassive PE, SIR encourages data collection with institutional review board oversight and strongly recommends that local practices and treatment outcomes be reviewed periodically for quality-improvement purposes. Before undertaking CDT, a careful assessment should be performed to detect clinical factors that might increase the risk of bleeding or diminish the importance of any clinical benefit achieved.
  • The SIR strongly supports the conduct of new RCTs and other prospective studies on the use of CDT for acute PE, in particular for submassive PE, with a focus on studying long-term outcomes and possible prevention of PPS and CTEPH.

For patients who undergo CDT for PE, SIR suggests the following precautions:
(i) patients should be closely monitored in an advanced care unit;
(ii) US guidance for venous puncture should be routinely used to reduce bleeding risk;
(iii) because of its suspected association with severe adverse events, use of the AngioJet Rheolytic Thrombectomy System should probably be avoided except in the context of a prospective study;
(iv) to minimize the risk of compromising the condition of patients in stable condition, mechanical interventions should usually be avoided in patients with submassive PE unless as part of a prospective study; and
(v) if heparin is given during thrombolytic infusion, subtherapeutic dosing (eg, 300–500 U/h or less than 2× normal partial thromboplastin time) is suggested to reduce bleeding risk.

To access this paper, please click here