Systemic Thrombolytic Therapy and Catheter-Directed Fragmentation with Local Thrombolytic Therapy in Patients with Pulmonary Embolism

Ultrasound-Facilitated, Catheter-Directed Thrombolysis for Acute Pulmonary Embolism

BACKGROUND

Acute pulmonary embolism (APE) poses a significant risk to patient health, with treatment options varying in efficacy and safety. Ultrasound-facilitated catheter-directed thrombolysis (USCDT) has emerged as a potential alternative to conventional catheter-directed thrombolysis (CDT) for patients with intermediate to high-risk APE. This study aimed to compare the efficacy and safety of USCDT versus conventional CDT in patients with intermediate to high-risk APE.

METHODS

This observational retrospective study was conducted at the Armed Forces Hospital, Al-Hada, Taif, the Kingdom of Saudi Arabia (KSA), on 135 patients diagnosed with APE and treated with either USCDT or CDT (58 underwent CDT, while 77 underwent USCDT). The primary efficacy outcome was the change in the right ventricle to the left ventricle (RV/LV) diameter ratio. Secondary outcomes included changes in pulmonary artery systolic pressure and the Miller angiographic obstruction index score. Safety outcomes focused on major bleeding events.

RESULTS

Both USCDT and CDT significantly reduced RV/LV diameter ratio (from 1.35 ± 0.14 to 1.05 ± 0.17, P < 0.001) and systolic pulmonary artery pressure (SPAP) (from 55 ± 7 mmHg to 38 ± 7 mmHg, P < 0.001) at 48- and 12-hours post-procedure, respectively, with no significant differences between treatments. However, USCDT was associated with a significantly lower rate of major bleeding events compared to CDT (0% vs. 3.4%, P = 0.008). Multivariate logistic regression analysis revealed that USCDT was associated with a 71.9% risk reduction of bleeding (OR = 0.281, 95% CI = 0.126 - 0.627, P = 0.002).

CONCLUSIONS

USCDT is a safe and effective alternative to CDT for the treatment of intermediate to high-risk APE, as it significantly reduces the risk of major bleeding.

Risk stratification of acute pulmonary embolism

Approximately 5% of pulmonary embolism (PE) cases present with persistent hypotension, obstructive shock, or cardiac arrest. Given the high short-term mortality, management of high-risk PE cases focuses on immediate reperfusion therapies. Risk stratification of normotensive PE is important to identify patients with an elevated risk of hemodynamic collapse or an elevated risk of major bleeding. Risk stratification for short-term hemodynamic collapse includes assessment of physiological parameters, right heart dysfunction, and identification of comorbidities. Validated tools such as European Society of Cardiology guidelines and Bova score can identify normotensive patients with PE and an elevated risk of subsequent hemodynamic collapse. At present, we lack high-quality evidence to recommend one treatment over another (systemic thrombolysis, catheter-directed therapy, or anticoagulation with close monitoring) for patients at elevated risk of hemodynamic collapse. Newer, less well-validated scores such as BACS and PE-CH may help identify patients at a high risk of major bleeding following systemic thrombolysis. The PE-SARD score may identify those at risk of major anticoagulant-associated bleeding. Patients at low risk of short-term adverse outcomes can be considered for outpatient management. The simplified Pulmonary Embolism Severity Index score or Hestia criteria are safe decision aids when combined with physician global assessment of the need for hospitalization following the diagnosis of PE.

The safety and efficacy of systemic versus catheter-based therapies: application of a prognostic model by a pulmonary embolism response team

The decision by pulmonary embolism response teams (PERTs) to utilize anticoagulation (AC) with or without systemic thrombolysis (ST) or catheter-directed therapies (CDT) for pulmonary embolism (PE) is a balance between the desire for a positive outcome and safety. Our primary aim was to develop a predictive model of in-hospital mortality for patients with high- or intermediate-risk PE managed by PERT while externally validating this model. Our secondary aim was to compare the relative safety and efficacy of ST and CDT in this cohort. Consecutive patients hospitalized between June 2014 and January 2020 at the Cleveland Clinic Foundation and The University of Rochester with acute high- or intermediate-risk PE managed by PERT were retrospectively evaluated. Groups were stratified by treatment strategy. The primary outcome was in-hospital mortality, and secondary outcome was major bleeding. A logistic regression model to predict the primary outcome was built using the derivation cohort, with 100-fold bootstrapping for internal validation. External validation was performed and the area under the receiver operating curve (AUC) was calculated. Of 549 included patients, 421 received AC alone, 71 received ST, and 64 received CDT. Predictors of major bleeding include ESC risk category, PESI score, hypoxia, hemodynamic instability, and serum lactate. CDT trended towards lower mortality but with an increased risk of bleeding relative to ST (OR = 0.42; 95% CI [0.15, 1.17] and OR = 2.14; 95% CI [0.9, 5.06] respectively). In the multivariable logistic regression model in the derivation institution cohort, predictors of in-hospital mortality were age, cancer, hemodynamic instability requiring vasopressors, and elevated NT-proBNP (AUC = 0.86). This model was validated using the validation institution cohort (AUC = 0.88). We report an externally-validated model for predicting in-hospital mortality in patients with PE managed by PERT. The decision by PERT to initiate CDT or ST for these patients had no impact on mortality or major bleeding, yet the long-term efficacy of these interventions needs to be elucidated.

Catheter directed compared to systemically delivered thrombolysis for pulmonary embolism: a systematic review and meta-analysis

To compare the efficacy and safety of systemic and catheter directed thrombolysis for patients with pulmonary embolism. Pubmed and Cochrane Central Register of Controlled Trials were systematically searched from inception to May 31st 2020 to identify relevant studies. Outcomes of interest were in-hospital mortality and major bleeding including intracranial hemorrhage. We included 8 observational studies comprising 11,932 patients with PE. Catheter directed thrombolysis was associated with lower in-hospital mortality [RR 0.52; 95% confidence interval (CI) 0.40-0.68]. Although there was no difference in major bleeding by treatment strategy (RR 0.80; 95% CI 0.37-1.76), intracranial hemorrhage was lower in patients receiving catheter directed therapy (RR 0.66; 95% CI, 0.47-0.94).The certainty in these estimates was low. Non-randomized studies suggest that catheter directed delivery of thrombolytic therapy may be associated with lower in-hospital mortality and intracranial hemorrhage rates. These results may help inform management strategies for health care and pulmonary embolism response teams (PERT) involved in the management of high risk patients with massive or submassive pulmonary emboli.