Catheter-directed Thrombolysis versus Systemic Anticoagulation for Submassive Pulmonary Embolism: A Meta-Analysis

Cutting-Edge Techniques and Drugs for the Treatment of Pulmonary Embolism: Current Knowledge and Future Perspectives

Pulmonary embolism (PE) is a potentially life-threatening condition requiring prompt diagnosis and treatment. Recent advances have led to the development of newer techniques and drugs aimed at improving PE management, reducing its associated morbidity and mortality and the complications related to anticoagulation. This review provides an overview of the current knowledge and future perspectives on PE treatment. Anticoagulation represents the first-line treatment of hemodynamically stable PE, direct oral anticoagulants being a safe and effective alternative to traditional anticoagulation: these drugs have a rapid onset of action, predictable pharmacokinetics, and low bleeding risk. Systemic fibrinolysis is suggested in patients with cardiac arrest, refractory hypotension, or shock due to PE. With this narrative review, we aim to assess the state of the art of newer techniques and drugs that could radically improve PE management in the near future: (i) mechanical thrombectomy and pulmonary embolectomy are promising techniques reserved to patients with massive PE and contraindications or failure to systemic thrombolysis; (ii) catheter-directed thrombolysis is a minimally invasive approach that can be suggested for the treatment of massive or submassive PE, but the lack of large, randomized controlled trials represents a limitation to widespread use; (iii) novel pharmacological approaches, by agents inhibiting thrombin-activatable fibrinolysis inhibitor, factor Xia, and the complement cascade, are currently under investigation to improve PE-related outcomes in specific settings.

A comparison of the efficacy and safety between anticoagulation alone and combined with catheter-directed thrombolysis for treatment of pulmonary embolism on outcome: A systematic review and meta-analysis

BACKGROUND

Catheter-directed thrombolysis (CDT) is one of the newest treatment options for submassive pulmonary embolism (sPE). This study will compare the efficacy and safety of catheter-directed thrombolysis (CDT) combine with anticoagulation versus anticoagulation alone (AC) in patients with PE.

METHODS

A database search was conducted using PubMed, EMBASE, Cochrane Library, and Clinicaltrials.gov for trials that compared CDT with AC in patients with pulmonary embolism. The primary outcomes was1-year mortality. The secondary outcomes were in-hospital, 30 days, 90 days mortality, in-hospital major and minor bleeding (Thrombolysis in Myocardial Infarction (TIMI) classification), length of hospital stay (LOS), reduction of pulmonary arterial systolic pressure (PASP) and RV/LV diameter ratio.

RESULTS

A total of 16 articles (3 RCTs and 13 non-RCTs) and 10595 patients were included in this study. 2237 patients were in the CDT group and 8358 patients were in the AC group. CDT group was associated with significantly lower in-hospital mortality (2.1% vs 6.2%,OR:0.36, 95%CI:0.26-0.51, p < .00001,I2 = 0%), 30 days mortality (3.1% vs 8.6%,OR:0.39,95%CI:0.23-0.66, p = .0005, I2 = 0%), 90 days mortality (3.8% vs 7.7%,OR:0.49,95%CI:0.29-0.80,p = .005,I2 = 7%), 1-year mortality (6.1% vs 11%, OR:0.51, 95%CI:0.35-0.76, p = .0008,I2 = 36%) compared to AC group, especially in ultrasound-assisted thrombolysis (USAT) subgroup. There were no differences on major bleeding between two groups (1.8% vs 2.2%, OR:1.10, 95%CI:0.61-1.98, p = .75, I2 = 0%). Minor bleeding was significantly higher in CDT group than AC group (6.2% vs 3.8%, OR:1.93,95%CI:1.27-2.94.66, p = .002, I2 = 1%). CDT group significantly reduced PASP (WMD:11.90,95%CI:6.45-17.35, p < .0001, I2 = 72%) and RV/LV (WMD:0.17,95%CI:0.04-0.30, p = .009, I2 = 69%) rapidly than AC group after treatment. LOS was similar between two groups (WMD:0.02,95%CI: -0.68-0.73, p = .95, I2 = 51%).

CONCLUSION

Results thus confirmed that CDT reduced in-hospital, 30 days, 90 days and 1-year all-cause mortality in patients with sPE compared to AC, particularly in USAT subgroup. Nonetheless, CDT group was associated with a higher risk of minor bleeding.

Comparative Outcomes of Catheter-Directed Thrombolysis Plus Systemic Anticoagulation Versus Systemic Anticoagulation Alone in the Management of Intermediate-Risk Pulmonary Embolism in a Systematic Review and Meta-Analysis

There are limited and conflicting data on the initial management of intermediate-risk (or submassive) pulmonary embolism (PE). This study sought to compare the outcomes of catheter-directed thrombolysis (CDT) in combination with systemic anticoagulation (SA) to SA alone. A systematic search was conducted in MEDLINE, EMBASE, PubMed, and the Cochrane databases from inception to March 1, 2023 for studies comparing the outcomes of CDT + SA versus SA alone in intermediate-risk PE. The outcomes were in-hospital, 30-day, 90-day, and 1-year mortality; bleeding; blood transfusion; right ventricular recovery; and length of stay. Random-effects models was used to calculate the pooled incidence and risk ratios (RRs) with 95% confidence intervals (CIs). A total of 15 (2 randomized and 13 observational) studies with 10,549 (2,310 CDT + SA and 8,239 SA alone) patients were included. Compared with SA, CDT + SA was associated with significantly lower in-hospital mortality (RR 0.41, 95% CI 0.30 to 0.56, p <0.001), 30-day mortality (RR 0.34, 95% CI 0.18 to 0.67, p = 0.002), 90-day mortality (RR 0.34, 95% CI 0.17 to 0.67, p = 0.002), and 1-year mortality (RR 0.58, 95% CI 0.34 to 0.97, p = 0.04). There were no significant differences between the 2 cohorts in the rates of major bleeding (RR 1.39, 95% CI 0.72 to 2.68, p = 0.56), minor bleeding (RR 1.83, 95% CI 0.97 to 3.46, p = 0.06), and blood transfusion (RR 0.34, 95% CI 0.10 to 1.15, p = 0.08). In conclusion, CDT + SA is associated with significantly lower short-term and long-term all-cause mortality, without any differences in major/minor bleeding, in patients with intermediate-risk PE.

Angioscopy-Guided Selective Pulmonary Thrombectomy and Angioscopy-Monitored Systemic Thrombosis for a Pulmonary Embolism

Few modalities have the capacity to demonstrate massive or fragmented thrombi to evaluate the effect of catheter-based or systemic thrombosis for pulmonary embolism (PE). We herein present a patient who underwent a thrombectomy for PE using a non-obstructive general angioscopy (NOGA) system. Small floating mobile thrombi were aspirated using the original method, and massive thrombi were aspirated using the NOGA system. Systemic thrombosis was also monitored via NOGA for 30 minutes. Detachment of thrombi from the wall of the pulmonary artery began two minutes after infusion of a recombinant tissue plasminogen activator (rt-PA). Six minutes after thrombolysis, the thrombi lost their erythematous color, and the white thrombi gradually floated and dissolved. NOGA-guided selective pulmonary thrombectomy and NOGA-monitored systemic thrombosis contributed to improved patient survival. Rapid systemic thrombosis for PE using rt-PA was also demonstrated by NOGA.

Clinical efficacy and safety of ultrasound-assisted thrombolysis vs. standard catheter-directed thrombolysis in patients with acute pulmonary embolism: A study level meta-analysis of clinical trials

Aim

To compare the clinical efficacy of ultrasound-assisted thrombolysis (USAT) vs. standard catheter-directed thrombolysis (SCDT) in patients with acute pulmonary embolism (aPE).

Methods

This study analyzed the clinical outcomes of patients with non-low-risk aPE who received USAT or SCDT. The primary outcomes were all-cause death, total bleeding, and major bleeding. Secondary outcomes included pulmonary thrombotic load score (Miller), improvement in right ventricular-to-left ventricular ratio (RV/LV), dose and duration of the thrombolytic drug tissue plasminogen activator (tPA), length of stay (LOS) in the ICU, and total LOS in the hospital.

Results

A total of seven articles and 451 patients were included in this study. 241 patients were in the USAT group and 210 patients were in the SCDT group. There were no significant differences in all-cause mortality, total bleeding, and major bleeding between the two groups. Miller scores for pulmonary thrombus also showed no difference between the two groups, but pulmonary artery systolic pressure (PASP) was lower in the SCDT group after-treatment. The reduction of RV/LV from baseline was more pronounced in the SCDT group than in the USAT group (OR: -0.14, 95%CI: -0.20 to 0.07, P < 0.0001, I ² = 0%). Total dose of tPA and duration of infusion in the USAT group were lower than those in the SCDT group, but there was no significant statistical difference. LOS in the ICU was similar between the two groups, while LOS in the hospital was lower in the SCDT group.

Conclusion

This study did not detect any differences in all-cause mortality, total bleeding, and major bleeding between non-low-risk aPE patients treated with USAT or SCDT. Improvement in right ventricular function was better in the SCDT group, and hospital LOS was lower in the SCDT group.

Meta-Analysis Comparing Catheter-Directed Thrombolysis Versus Systemic Anticoagulation Alone for Submassive Pulmonary Embolism

The optimal therapy for submassive pulmonary embolism (sPE), defined by right ventricular dysfunction without hemodynamic instability, is uncertain. We conducted a systematic review and meta-analysis to compare the outcomes of catheter-directed thrombolysis (CDT) versus systemic anticoagulation (SA) alone in patients with sPE. We searched PubMed, EMBASE, Cochrane, ClinicalTrials.gov, and Google Scholar (from inception through May 2022) for studies comparing outcomes of CDT versus SA in sPE. Studies were identified, and data were extracted by 2 independent reviewers. We used a random-effects model to calculate risk ratios (RRs) with 95% confidence intervals (CIs). Outcomes included in-hospital, 30-day, 90-day, and 1-year mortality, major and minor bleeding, and need for blood transfusion. A total of 12 studies (1 randomized, 11 observational) with 9,789 patients were included. Compared with SA, CDT was associated with significantly lower in-hospital mortality (RR 0.41, 95% CI 0.30 to 0.56, p <0.00001), 30-day mortality (RR 0.37, 95% CI 0.18 to 0.73, p = 0.004), 90-day mortality (RR 0.36, 95% CI 0.17 to 0.72, p = 0.004), and a tendency toward lower 1-year mortality (RR 0.56, 95% CI 0.29 to 1.05, p = 0.07). The risks of major bleeding (RR 1.31, 95% CI 0.57 to 3.01, p = 0.53), minor bleeding (RR 1.67, 95% CI 0.77 to 3.63, p = 0.20), and the rates of blood transfusion (RR 0.34, 95% CI 0.10 to 1.15, p = 0.08) were similar between the 2 strategies. In conclusion, in patients with sPE, CDT is associated with significantly lower in-hospital, 30-day, and 90-day mortality and a tendency toward lower 1-year mortality with similar bleeding rates compared with SA. This study expands the evidence supporting CDT as first-line therapy for sPE, and randomized controlled trials are indicated to confirm our findings.

Catheter-Based Therapies Decrease Mortality in Patients With Intermediate and High-Risk Pulmonary Embolism: Evidence From Meta-Analysis of 65,589 Patients

Background

Catheter-directed therapies (CDT) are an alternative to systemic thrombolysis (ST) in pulmonary embolism (PE) patients, but the mortality benefit of CDT is unclear.

Objective

We conducted a systematic review with meta-analysis to compare the efficacy and safety of CDT and ST in intermediate-high and high-risk PE.

Methods

We included (P) participants, adult PE patients; (I) intervention, CDT; (C) comparison, ST; (O) outcomes, mortality, complications, in-hospital treatment, and length of hospital stay; (S) study design, randomized controlled trials (RCTs), or cohort comparing CDT and ST. The primary endpoint was 30-day mortality. Secondary outcomes included treatment-related complications including bleeding, the use of hospital resources, and length of hospital stay.

Results

Eleven studies including 65,589 patients met the inclusion criteria. Thirty-day mortality was lower in the CDT group, compared to ST group [7.3 vs. 13.6%; odds ratio (OR) = 0.51, 95% confidence interval (CI) 0.38–0.69, p < 0.001]. The rates of myocardial injury, cardiac arrest, and stroke were lower in CDT group, compared to ST group (p < 0.001 for all). The rates of any major bleeding, intracranial hemorrhage, hemoptysis, and red blood cell transfusion were lower in patients treated with CDT, compared to ST (p ≤ 0.01 for all). Extracorporeal life support was used more often in patients treated with CDT, compared to ST (0.5 vs. 0.2%, OR = 2.52, 95% CI 1.88–3.39, p < 0.001). The use of hospital resources and length of hospital stay were comparable in both groups.

Conclusion

CDT might decrease mortality in patients with intermediate-high and high-risk PE and were associated with fewer complications, including major bleeding.

Association of annual volume and in-hospital outcomes of catheter-directed thrombolysis for pulmonary embolism

OBJECTIVE

We sought to evaluate the association between the institutional volume of catheter-directed thrombolysis (CDT) for pulmonary embolism and in-hospital mortality.

BACKGROUND

CDT is an increasingly utilized therapy in patients with intermediate/high-risk PE. However, data on the relationship between hospital volume and clinical outcomes remain limited.

METHODS

Patients who underwent CDT between October 1, 2015, and March 31, 2021, were identified in the Vizient Clinical Database. The primary outcome was in-hospital mortality. Secondary outcome were major complications, length of stay, and cost. Hospitals were dichotomized into <8 and ≥ 8 cases/year following restricted cubic spline analysis.

RESULTS

A total of 6741 CDT procedures at 171 hospitals were included with a median annual hospital volume of 4.1 cases (IQR = 1.9-8.3). A total of 44 hospitals (25.7%) were classified as high-volume ( ≥ 8 cases/year) and performed 60.9% of all CDT cases. CDT at high-volume centers was associated with lower in-hospital mortality (6.0% vs. 11.3%; p < 0.0001). Stroke and bleeding rates were similar, but pulmonary complications were more frequent at low-volume centers. CDT at high volume centers was associated with a significantly shorter length of stay and lower cost. The association between high CDT volume and in-hospital mortality persisted after adjustment for demographics (odds ratio [OR] = 0.49, [0.41-0.58]), demographics and risk factors (OR = 0.52 [0.44-0.62]), and demographics, risk factors, and troponin elevation (OR = 0.51 [0.40-0.66]).

CONCLUSION

In a large contemporary cohort of patients undergoing CDT in the United States, low annual institutional volume of CDT was associated with higher in-hospital mortality.