Shock Syndromes II
Catheter-directed thrombolysis (CDT) is an emerging treatment that enables the administration
of lower-dose thrombolytic agents directly into the thrombus.
| (a) | CDT has the advantage of concurrent mechanical disruption, including ultrasound- |
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assisted fragmentation, aspiration, or embolectomy.
| (b) | Applying CDT, several clinical trials have shown improved hemodynamics and strain on |
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the RV with minimal risk of a major bleed (less than 1%).
| (c) | However, prospective comparative studies evaluating long-term outcomes with CDT are |
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currently lacking, and the site experiences and resources required limit widespread use.
| (d) | The 2021 CHEST guidelines recommend systemic thrombolytic therapy over CDT for |
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most patients; however, CDT may be considered in patients with acute PE associated with
hypotension who also have high bleeding risk, failed systemic therapy, or shock likely to
cause death before systemic thrombolysis can take effect.
xi.
Reduced-dose thrombolytic therapy has been investigated as a strategy to minimize bleeding
risk.
| (a) | Several trials have evaluated βhalf-doseβ alteplase compared with full dose, showing |
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improved hemodynamic parameters and potentially less bleeding, but all trials had severe
methodological limitations that limit generalizability.
| (b) | A retrospective database of 3768 patients showed that patients who received half-dose |
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alteplase were more likely to require treatment escalation (53.8% vs. 41.4%; p<0.01)
driven by secondary thrombolysis without notable difference in bleeding complications.
| (c) | Given the available data, experts do not recommend consideration for half-dose in PE |
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management. For patients who need reperfusion treatment because of hemodynamic
decompensation but who have absolute or relative contraindications to systemic
fibrinolysis, CDT is recommended.
| (d) | The PEITHO-3 trial (NCT04430569) aims to compare the efficacy and safety of reduced- |
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dose alteplase with standard heparin in patients with intermediate-high risk PE. Results
are expected to have a major impact on risk-adjusted acute PE treatment and guideline
recommendations.
xii.
Patients with a massive or submassive PE should be considered for surgical embolectomy or
catheter thrombectomy if they (1) have an unacceptably high risk of bleeding if administered
thrombolytics, (2) remain unstable despite thrombolytic administration, or (3) have shock
likely to cause death within hours (before the onset of systemic thrombolytics).
xiii.
Unless contraindicated, all patients should also receive a parenteral anticoagulant.
| (a) | Intravenous unfractionated heparin is recommended over alternative agents for patients in |
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whom thrombolytic therapy is being considered or planned.
| (b) | The alteplase package insert recommends holding heparin during the alteplase infusion |
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and reinstituting it when the aPTT returns to less than 2 times the upper limit of normal.
| (c) | However, in some clinical trials, heparin was continued during thrombolytic administration. |
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| (d) | Therefore, concurrent heparin administration with thrombolytic therapy in practice |
varies, and this decision should be individualized on the basis of risk assessment (e.g.,
bleeding vs. hemodynamics). If anticoagulation is contraindicated, an inferior vena cava
filter should be placed.
in the United States. This study analyzed data from the Nationwide Inpatient Sample for 2016β2018 and
identified 1,124,204 hospitalizations for acute PE among U.S. adults, with the disease of 66,570 patients
(5.9%) classified as high risk. The study found that the hospitalization rate for PE increased across racial and
ethnic groups, with Black people having the highest rate at 20.1 per 10,000 person-years, followed by White
people at 13.1 per 10,000 person-years.