Catheter-directed thrombolysis with the Endowave system in the treatment of acute massive pulmonary embolism: a retrospective multicenter case series

Comparison of outcomes and complications in conventional versus ultrasound-accelerated catheter directed thrombolysis for treatment of pulmonary embolism: A systematic review and meta-analysis

BACKGROUND

Acute submassive a massive pulmonary embolism are known as leading causes of cardiovascular morbidity and mortality in emergency departments. Choosing the optimal type of catheter directed thrombolysis (CDT) for treatment of pulmonary embolism presents a quandary to the practitioners. To the best of our knowledge, there is no meta-analysis comparing superiority of conventional CDT and ultrasound-accelerated catheter directed thrombolysis (USACDT). Therefore, in this meta-analysis, we aimed to compare conventional CDT with USACDT regarding clinical outcomes and safety profile.

METHODS

A systematic literature search of previous published studies comparing conventional CDT with USACDT regarding clinical outcomes and safety profile was carried out in the electronic databases including MEDLINE, Scopus, EBSCO, Google Scholar, Web of Science, and Cochrane from inception to December 2021. Data were analyzed by comprehensive meta-analysis software (CMA, version 3).

RESULTS

The meta-analysis included nine studies with a total of 705 patients. Our meta-analysis showed that there is no significant difference between two groups with respect to pulmonary arterial systolic pressure (SMD: -0.084; 95% CI: -0.287 to 0.12; p: 0.41), RV/LV (SMD: -0.003; 95% CI: -0.277 to 0.270; p: 0.98), and Miller score (SMD: -0.345; 95% CI: -1.376 to 0.686; p: 0.51). Similarly, we found no statistically significant differences between two groups regarding major and minor bleeding (p > .05).

CONCLUSION

Our meta-analysis showed that when compared with USACDT, conventional CDT provides similar clinical and hemodynamic outcomes or safety for treatment of pulmonary embolism without the need for very expensive technologies. However, randomized clinical trials are required to further investigate cost-effectiveness of USACDT in comparison with conventional CDT.

An Update on the Management of Acute High-Risk Pulmonary Embolism

Hemodynamic instability and right ventricular (RV) dysfunction are the key determinants of short-term prognosis in patients with acute pulmonary embolism (PE). High-risk PE encompasses a wide spectrum of clinical situations from sustained hypotension to cardiac arrest. Early recognition and treatment tailored to each individual are crucial. Systemic fibrinolysis is the first-line pulmonary reperfusion therapy to rapidly reverse RV overload and hemodynamic collapse, at the cost of a significant rate of bleeding. Catheter-directed pharmacological and mechanical techniques ensure swift recovery of echocardiographic parameters and may possess a better safety profile than systemic thrombolysis. Further clinical studies are mandatory to clarify which pulmonary reperfusion strategy may improve early clinical outcomes and fill existing gaps in the evidence.

Clinical outcomes of very elderly patients treated with ultrasound-assisted catheter-directed thrombolysis for pulmonary embolism: a systematic review

Pulmonary embolism (PE) is a significant cause of death in the very elderly (≥ 75 years) population. Ultrasound-assisted catheter-directed thrombolysis (USCDT) emerges to improve thrombolysis safety and efficacy. However, outcomes in very elderly patients are unknown, as randomized controlled trials exclude this population. Recently, we demonstrated acute kidney injury (AKI) and ischemic hepatitis in an octogenarian intermediate-risk PE patient treated with USCDT. Considering the lack of evidence, we undertook a systematic review to evaluate the clinical outcomes in very elderly PE patients treated with USCDT. We searched for very elderly PE patients treated with USCDT from 2008 to 2019. Additionally, we conducted another systematic review without age restriction to update previous evidence and compare both populations. We also did an exploratory analysis to determine if thrombolysis was followed based on current guidelines or impending clinical deterioration factors. We identified 18 very elderly patients (age 79.2, 75-86), mostly female and with intermediate-risk PE. We found an intracranial hemorrhage (ICH), and a right pulmonary artery rupture. Additionally, two significant bleedings complicated with transient AKI, and one case of AKI and ischemic hepatic injury. The patients who survived all had clinical and echocardiographic in-hospital improvement. Despite low rt-PA doses, ICH and major bleeding remain as feared complications. Thrombolysis decision was driven by impending clinical deterioration factors instead of international guideline recommendations. Our data do not suggest prohibitive risk associated with USCDT in very elderly intermediate and high-risk PE patients. Despite long-term infusions and right ventricular dysfunction, AKI and ischemic hepatic injury were infrequent.

Feasibility of ultrasound-assisted catheter-directed thrombolysis for submassive pulmonary embolism: A meta-analysis of case series

BACKGROUND

During the past few years, there has been a surge in the use of ultrasound-assisted catheter-directed thrombolysis (UACDT) for submassive pulmonary embolism (SPE). However, few studies evaluated the feasibility of UACDT for SPE.

PURPOSE

To evaluate the feasibility of UACDT in treating SPE.

METHODS

A comprehensive search of online databases was performed. Search terms UACDT in SPE were entered into PubMed, Embase, Scopus and the Cochrane Library to identify related articles published until October 2018. A quality assessment and data extraction were performed by two researchers. Meta-analysis was performed using R statistical software.

RESULTS

Twelve studies with 485 patients were included in this meta-analysis. The pooled right ventricular/left ventricular ratio decrease and pulmonary artery systolic pressure drop after treatment was -0.34 (95% CI: -0.43, -0.25) and -15.05 (95% CI: -18.10, -12.00) mm Hg, respectively. The pooled major bleeding rate was 1.0% (95% CI: 0.0%, 3.0%), and the in-hospital mortality was 0.0% (95% CI: 0.0%, 1.0%).

CONCLUSION

This up to data meta-analysis confirms that UACDT is a feasible treatment for SPE.

Nursing Care Practices for Patients With Pulmonary Embolism Undergoing Treatment With Ultrasound-Assisted Thrombolysis: An Integrative Review

BACKGROUND

Pulmonary embolism (PE) remains a common and life-threatening event. The use of ultrasound-assisted thrombolysis (USAT) for the delivery of thrombolytic agents to the clot has developed in the last 10 years. A search yielded no evidence-based practice guidelines for the nursing care of the patient with PE during and post USAT treatment and specifically when using the EKOS machine.

OBJECTIVE

The objective of this integrative review was to explore the literature and web for any information on the use of USAT for adults with PE both during and post treatment. Our goal was to examine nurse-specific practices to develop appropriate protocols.

METHODS

We conducted a search of PubMed, Web of Science, EBSCOhost, CINAHL, Google Scholar, and Google for any guidelines, observational studies, or experimental studies using USAT for PE in adults. Nurse authors independently reviewed the articles using a standardized data coding form. Information abstracted included sample and setting characteristics, access characteristics, medication, sheath removal, compression, and bleeding events.

RESULTS

Twenty-two articles, published in 2008-2019, met the eligibility criteria. Most studies were small retrospective studies at single sites. Variation existed on the clinician, the clinical area for placement, the amount and duration of delivery of medication, and where care was provided during the infusion. Few studies noted sheath removal or compression procedures. Fifteen studies reported 1 fatal, 12 major, 4 moderate, and 36 minor bleeding events at the catheter insertion sites.

CONCLUSION

There is lack of sufficient information for the development of nursing practice guidelines for this new technology.

Catheter-directed therapy for acute pulmonary embolism: navigating gaps in the evidence

Systemic thrombolysis for acute pulmonary embolism (PE) reduces the risk of death and cardiovascular collapse but is associated with an increased rate of bleeding. The desire to minimize the risk of bleeding events has driven the development of catheter-based strategies for pulmonary reperfusion in PE. These catheter-based strategies utilize lower-dose fibrinolytic regimens or purely mechanical techniques to expedite removal of the embolus. Several devices providing mechanical or suction embolectomy and catheter-directed thrombolysis, with or without facilitation by ultrasound, have been tested. Data are inconsistent regarding the efficacy and safety of mechanical and suction embolectomy. The most comprehensive data on catheter-based techniques stem from trials of ultrasound-facilitated catheter fibrinolysis. Ultrasound-facilitated catheter fibrinolysis relieves right ventricular pressure overload with a lower risk of major bleeding and intracranial haemorrhage than historical rates with systemic fibrinolysis. However, further research is required to determine the optimal application of ultrasound-facilitated catheter fibrinolysis and other catheter-based therapies in patients with acute PE.

Meta-Analysis of Catheter Directed Ultrasound-Assisted Thrombolysis in Pulmonary Embolism

Ultrasound-assisted catheter directed thrombolysis (USAT) has been shown to improve hemodynamic function and reduce bleeding complications in patients with acute massive or submassive pulmonary embolism. We performed a meta-analysis to better evaluate the efficacy and safety of USAT. We conducted an extensive literature search in PUBMED, MEDLINE, and EMBASE databases from January 1, 2008 to December 31, 2018. Efficacy outcomes of interest were pulmonary artery systolic pressure, mean pulmonary pressure, ratio of right ventricular to left ventricular diameter, cardiac index, tricuspid annular plane systolic excursion, Miller Index Score, and Qanadli Score. Safety outcomes were in-hospital mortality, long-term mortality, major and minor bleeding complications, and recurrent pulmonary embolism. Meta-analysis was performed using Cochrane Collaboration Review Manager (version 5.1). Effect size was estimated using random effects model, with 95% confidence intervals (CIs). Twenty-eight studies (n = 2,135) met inclusion criteria. Compared with pretreatment parameters, post-USAT was associated with a reduction in the mean Miller Index Score and Qanadli Score by 10.55 (95% CI -12.98 to -8.12) and 15.64 (95% CI -19.08 to -12.20), respectively. Cardiac index and tricuspid annular plane systolic excursion improved by 0.68 L/m² (95% CI 0.49 to 0.87) and 3.68 mm (95% CI 2.43 to 4.93), respectively. Pulmonary artery systolic pressure and mean pulmonary pressure after therapy were reduced by a mean difference of 16.69 mm Hg (95% CI -19.73 to -13.65) and 12.13 mm Hg (95% CI -14.67 to -9.59) respectively. The right ventricular to left ventricular diameter dimension ratio decreased by 0.35 (95% CI -0.40 to -0.30) after therapy. In-hospital mortality in patients who underwent USAT was 2.9%, and total long-term mortality was 4.1%. Major and minor bleeding complications were seen in in 5.4% and 6.0% of patients, respectively. Recurrent events occurred in 0.2% of patients after USAT. In conclusion, USAT is a safe and effective procedure associated with significant hemodynamic and clinical improvement in patients with massive and submassive pulmonary embolism.

The implementation of a pulmonary embolism response team in the management of intermediate- or high-risk pulmonary embolism

BACKGROUND

Massive and submassive pulmonary embolism (PE) can be life-threatening. Treatment options include anticoagulation, fibrinolysis, catheter-directed or open surgical thrombus removal, and extracorporeal membrane oxygenation. With increasing patient complexity and advanced therapeutic options, the approach to optimal care for patients with intermediate- to high-risk PE is not clearly established. Multidisciplinary, rapid response teams can optimize risk stratification and expedite management. A PE response team (PERT) composed of specialists from cardiology, vascular surgery, emergency medicine, pulmonary and critical care, interventional radiology, cardiac surgery, hospital medicine, and pharmacy was created at our institution. The team is tasked with evaluating and treating patients with massive and submassive PE by use of a risk stratification and treatment algorithm. We describe our initial experience with this approach.

METHODS

The records of patients treated by the PERT since inception in October 2015 through May 2017 were reviewed (intervention group). The diagnoses codes of the PERT patients were retrieved from the Vizient database. A retrospective control cohort group was created using these specific diagnoses and a matching set of demographics (age, sex), Medicare Severity Diagnosis Related Group, admission severity of illness, and admission risk of mortality. Statistical analysis was performed using the Fisher exact test, the Pearson χ² statistic, Student t-test, and Cochran-Cox approximation. P < .05 was considered significant.

RESULTS

During the time interval, 77 patients with massive or submassive PE were treated by PERT activation; 992 patients included in the control group were treated at the discretion of an attending physician without use of the algorithm from October 2013 to 2016. Both groups had similar demographics, similar distribution of risk of mortality and severity of illness, and similar average Medicare Severity Diagnosis Related Group weighting. There was no statistically significant difference in the mortality rate between the two groups. The PERT group had significantly lower intensive care unit stay and overall length of stay. No difference was seen in direct cost between the two groups despite higher use of interventional treatment modalities in the PERT group.

CONCLUSIONS

In our institution, assembly of a dedicated team to treat patients with massive or submassive PE according to a clinical algorithm resulted in expedited treatment and reduced variation of care. Intensive care unit stay and overall length of stay were reduced by this approach, with no impact on direct cost despite the use of advanced modalities of treatment. We believe that this paradigm can be of potential value in other disease entities, particularly when multiple disciplines are involved.

Tissue plasminogen activator dose and pulmonary artery pressure reduction in catheter directed thrombolysis of submassive pulmonary embolism

Purpose

The purpose of this study is to assess the incremental effect of tissue plasminogen activator (t-PA) dose on pulmonary artery pressure (PAP) and bleeding during catheter directed thrombolysis (CDT) of submassive pulmonary embolism (PE).

Materials and methods

Records of 46 consecutive patients (25 men, 21 women, mean age 55±14 y) who underwent CDT for submassive PE between September 2009 and February 2017 were retrospectively reviewed. Mean t-PA rate was 0.7±0.3 mg/h. PAP was measured at baseline and daily until CDT termination. Mixed-effects regression modeling was performed of repeated PAP measures in individual patients. Bleeding events were classified by Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) and t-PA dose at onset.

Results

Mean t-PA dose was 43.0±30.0 mg over 61.9± 28.8 h. Mean systolic PAP decreased from 51.7±15.5 mmHg at baseline to 35.6±12.7 mmHg at CDT termination (p<0.001). Mixed-effects regression revealed a linear decrease in systolic PAP over time (β = -0.37 (SE = 0.05), p<0.001) with reduction in mean systolic PAP to 44.8±1.9 mmHg at 12 mg t-PA/20 h, 39.5±2.0 mmHg at 24 mg t-PA/40 h, and 34.9±2.1 mmHg at 36 mg/60 h. No severe, one moderate, and 8 mild bleeding events occurred; bleeding onset was more frequent at ≤24 mg t-PA (p <0.001). One patient expired from cardiopulmonary arrest after 16 h of CDT (15.4 mg t-PA); no additional intra-procedural fatalities occurred.

Conclusion

Increased total t-PA dose and CDT duration were associated with greater PAP reduction without increased bleeding events.

Efficacy evaluation of reteplase in a novel canine acute pulmonary thromboembolism model developed by minimally invasive surgery and digital subtraction angiography

Purpose

In order to evaluate the thrombolytic effects of reteplase in pulmonary thromboembolism (PTE), we developed a novel canine PTE model. The efficacy of reteplase against PTE in comparison to alteplase was clarified for the first time, and this PTE model could be further applied to studies of novel thrombolytic therapies.

Patients and methods

Twenty-four dogs were divided into four groups: sham operation, vehicle, alteplase, and reteplase. Autologous thrombi/saline were injected into the pulmonary artery, and thrombolytic agents were administrated. Thrombus formation and dissolution were monitored by real-time digital subtraction angiography (DSA), and pulmonary pressures were measured simultaneously. Blood coagulation, blood gas, hematology, and histopathologic examinations were used as subsidiary methods.

Results

The canine PTE model was established with a significant decrease of blood flow and ~75% blocking area. Administration of reteplase (0.6 mg/kg) resulted in effective thrombus dissolution with a recovery of over 80% blood flow, as effective as alteplase (1.6 mg/kg). Correspondingly, the elevated pulmonary systolic, diastolic, and mean arterial pressures declined to the normal level. Blood coagulation was changed by reteplase, with a dramatic elongation of prothrombin time, activated partial thromboplastin time, and thrombin time, even longer than alteplase. In contrast to the vehicle group, no obvious pathological changes were found in the two thrombolytic groups. Hematological, blood biochemical, and blood gas results also indicated that reteplase had no adverse reactions in this PTE model.

Conclusion

Reteplase proved to be an effective and safe therapy for PTE for the first time, and a small dosage of reteplase exerted an efficacy comparable to the routine dosage of alteplase. Our findings indicated the potential of reteplase as clinical treatment against PTE. This technically innovative, stability- and validity-proved canine PTE model developed by minimally invasive surgery and DSA resembled major clinical features. This may further facilitate our understanding of thrombotic disorders and development of prophylactic and therapeutic approaches.

Acute Massive Pulmonary Thromboembolism Treated by Selective Catheter-Directed Thrombolysis

BACKGROUND

To evaluate the safety and efficacy of selective catheter-directed thrombolysis (SCDT) in treating acute massive pulmonary thromboembolism (AMPTE).

METHODS

Twenty-six AMPTE patients were enrolled between March 2010 and March 2013. A Uni*Fuse infusion system was inserted into the main pulmonary artery thrombus. The thrombolytic regimen included an intraoperative bolus injection of 250,000 IU urokinase, followed by continuous thrombolytic infusion of 5,000 IU/kg per (every) 24 hr urokinase for 72 hr postoperatively. Clinical symptoms, shock index (SI), systolic pulmonary artery pressure (sPAP), peripheral arterial partial pressure of oxygen (PaO₂), and Miller index (MI) were assessed before and after treatment.

RESULTS

The patients included 16 men and 10 women (49.9 ± 18.8 years old; time to onset of 50.2 ± 28.5 hr). After thrombolysis, dyspnea and cough were relieved to varying degrees; chest pain, hemoptysis, and syncope disappeared. Importantly, a clinical success rate of 100% was achieved. All objective indices were improved: SI decreased from 1.74 ± 0.38 before operation to 0.71 ± 0.09 postoperatively (P = 0.00); PaO₂ increased from 52.78 ± 6.92 mm Hg to 85.98 ± 5.91 mm Hg (P = 0.00); sPAP was reduced from 65.19 ± 8.22 mm Hg to 34.42 ± 4.05 mm Hg (P = 0.00); MI dropped from 0.69 ± 0.09 to 0.33 ± 0.06 (P = 0.00). Mean total urokinase amounts were 1,298,000 IU for each patient. Postoperative complications included 2 cases of puncture-site hematoma (cured by pressure bandage) and 1 case of gastrointestinal hemorrhage (healed by conservative treatment without blood transfusion).

CONCLUSIONS

SCDT may be considered a safe and efficacious treatment for AMPTE.

Catheter-Directed Therapy for Pulmonary Embolism: Patient Selection and Technical Considerations

Acute pulmonary embolism (PE) is the third most common cause of death among hospitalized patients. Treatment escalation beyond anticoagulation therapy is necessary in patients with cardiogenic shock and may be of benefit in select normotensive patients with right heart strain. Percutaneous catheter-based techniques (catheter-directed mechanical thrombectomy, clot maceration, and/or pharmacologic thrombolysis) as an alternative or adjunct to systemic thrombolysis can rapidly debulk central clot in patients with shock. Catheter-directed thrombolysis, which uses a low-dose intraclot prolonged thrombolytic infusion, is a promising but insufficiently studied therapy for patients presenting with acute intermediate-risk PE.

Echocardiographic assessment with right ventricular function improvement following ultrasound-accelerated catheter-directed thrombolytic therapy in submassive pulmonary embolism

Introduction The objective of this study was to evaluate the efficacy of ultrasound-accelerated catheter-directed thrombolytic therapy in patients with submassive pulmonary embolism. Methods Clinical records of 46 patients with submassive pulmonary embolism who underwent ultrasound-accelerated catheter-directed pulmonary thrombolysis using tissue plasminogen activator, from 2007 to 2017, were analyzed. All patients experienced clinical symptoms with computed tomography evidence of pulmonary thrombus burden. Right ventricular dysfunction was present in all patients by echocardiographic finding of right ventricle-to-left ventricle ratio > 0.9. Treatment outcome, procedural complications, right ventricular pressures, and thrombus clearance were evaluated. Follow-up evaluation included echocardiographic assessment of right ventricle-to-left ventricle ratio at one month, six months, and one year. Results Technical success was achieved in all patients ( n = 46, 100%). Our patients received an average of 18.4 ± 4.7 mg of tissue plasminogen activator using ultrasound-accelerated thrombolytic catheter with an average infusion time of 16.5± 5.4 h. Clinical success was achieved in all patients (100%). Significant reduction of mean pulmonary artery pressure occurred following the treatment, which decreased from 36 ± 8 to 21 ± 5 mmHg ( p < 0.001). There were no major bleeding complications. All-cause mortality at 30 days was 0%. No patient developed recurrent pulmonary embolism during follow-up. During the follow-up period, 43 patients (93%) showed improvement of right ventricular dysfunction based on echocardiographic assessment. The right ventricle-to-left ventricle ratio decreased from 1.32 ± 0.18 to 0.91 ± 0.13 at the time of hospital discharge ( p < 0.01). The right ventricular function remained improved at 6 months and 12 months of follow-up, as right ventricle-to-left ventricle ratio were 0.92 ± 0.14 ( p < 0.01) and 0.91 ± 0.15 ( p < 0.01), respectively. Conclusion Ultrasound-accelerated catheter-directed thrombolysis is a safe and efficacious treatment for submassive pulmonary embolism. It reduces pulmonary hypertension and improves right ventricular function in patients with submassive pulmonary embolism.

Comparison of Ultrasound-Accelerated versus Pigtail Catheter-Directed Thrombolysis for the Treatment of Acute Massive and Submassive Pulmonary Embolism

PURPOSE

To compare the technical and clinical effectiveness of ultrasound-accelerated endovascular thrombolysis (USAT) versus pigtail catheter-directed thrombolysis (PCDT) for the treatment of acute pulmonary embolism (PE).

MATERIALS AND METHODS

A single-center retrospective study of patients treated with USAT or PCDT for acute massive or submassive PE between January 2010 and December 2016 was performed by reviewing electronic medical records. Sixty treatments were reviewed (mean patient age, 56.7 y ± 14.6), including 52 cases of submassive PE (21 treated with USAT, 31 with PCDT) and 8 cases of massive PE (3 treated with USAT, 5 with PCDT). Endpoints included pulmonary artery pressure (PAP), Miller PE severity index, tissue plasminogen activator (TPA) dose, infusion duration, procedural variables, and complications.

RESULTS

Demographics, PE severity, and right:left ventricular diameter ratios were similar between groups. USAT and PCDT significantly reduced mean PAP (reductions of 7.4 mm Hg [P = .002] and 8.2 mm Hg [P < .001], respectively) and Miller index scores (reductions of 45.8% [P < .001] and 53% [P < .001], respectively) with similar effectiveness (P = .47 and P = .15, respectively). Procedure (P < .001) and fluoroscopy (P = .001) times were significantly longer in the USAT group. The USAT group underwent fewer sessions (2.2 ± 0.6 vs 2.4 ± 0.6; P = .17) with shorter infusion times (23.9 h ± 8.8 vs 30.4 h ± 12.6; P = .065) and a lower total dose of TPA (27.1 mg ± 11.3 vs 30.4 mg ± 12.6; P = .075) compared with the PCDT group, but the differences were not significant. Complications (P = .07) and 30-day mortality rates (P = .56) were not significantly different between groups.

CONCLUSIONS

USAT and PCDT demonstrated comparable effectiveness and safety in the treatment of patients with acute PE.

Interventional radiology treatment for pulmonary embolism

Venous thromboembolism (VTE) is an illness that has a potentially life-threatening condition that affects a large percentage of the global population. VTE with pulmonary embolism (PE) is the third leading cause of death after myocardial infarction and stroke. In the first three months after an acute PE, there is an estimated 15% mortality among submassive PE, and 68% mortality in massive PE. Current guidelines suggest fibrinolytic therapy regarding the clinical severity, however some studies suggest a more aggressive treatment approach. This review will summarize the available endovascular treatments and the different techniques with its indications and outcomes.

Ultrasound Assisted Catheter-Directed Thrombolysis of Acute Pulmonary Embolism: A Review of Current Literature

Pulmonary embolism continues as a very common and also presumably life-threatening disorder. For affected individuals with intermediate- as well as high-risk pulmonary embolism, catheter-based revascularization procedures have developed a possible substitute for systemic thrombolysis or for surgical embolectomy. Ultrasound-assisted catheter-directed thrombolysis is an innovative catheter-based approach; which is the main purpose of the present review article. Ultrasound-assisted catheter-directed thrombolysis is much more efficacious in reversing right ventricular dysfunction as well as dilatation in comparison to anticoagulation alone in individuals at intermediate risk. However, a direct comparison of ultrasound-assisted thrombolysis with systemic thrombolysis or surgical thrombectomy is not available. Ultrasound-assisted thrombolysis with early intrapulmonary thrombolytic bolus could also be successful in high-risk patients, but unfortunately, data from randomized trials is limited. This review article recapitulates existing information on ultrasound-assisted thrombolysis for acute pulmonary embolism.

Safety of catheter-directed thrombolysis for massive and submassive pulmonary embolism: Results of a multicenter registry and meta-analysis

OBJECTIVES

To evaluate the safety and efficacy of catheter-directed thrombolysis (CDT) in the treatment of acute pulmonary embolism (PE).

BACKGROUND

The use of CDT for the treatment of acute submassive and massive PE is increasing in frequency. However, its safety and efficacy have not been well elucidated.

METHODS

This study is made of two parts: one is a two-center registry of acute PE patients treated with CDT. The safety outcome evaluated was any major complication including fatal, intracranial (ICH), intraocular, or retroperitoneal hemorrhage or any overt bleeding requiring transfusion or surgical repair. The efficacy outcome was acute change in invasive pulmonary artery systolic pressure (PASP). The second part is a meta-analysis of all contemporary studies that used CDT for PE. Reported outcomes are the same as in the registry, with the addition of right ventricular to left ventricular (RV/LV) ratio change.

RESULTS

In the registry, 137 patients were included (age 59 ± 15, 50% male, 88% submassive PE). ICH occurred in two patients and major complications in 13 (9.4%). PASP decreased post procedure by 19 ± 15 mm Hg (95% CI 16-23). In the meta-analysis, 16 studies were included with 860 patients. Rate of ICH was 0.35% and the major complication rate was 4.65%, most requiring transfusion only. In-hospital mortality was 12.9% in the massive and 0.74% in the submassive group. All studies showed improvement in PASP and/or RV/LV ratio post CDT.

CONCLUSIONS

CDT is associated with a low major complication rate. Randomized studies are needed to evaluate its efficacy relative to anticoagulation alone. © 2017 Wiley Periodicals, Inc.

Ultrasound-Assisted Catheter-Directed Thrombolysis in High-Risk and Intermediate-High-Risk Pulmonary Embolism: Results From a Single-Center Cohort

We present our single-center results on ultrasound-assisted thrombolysis (USAT) in patients with pulmonary embolism (PE) at intermediate high risk (IHR) and high risk (HR). Our study consisted of 75 patients with PE who underwent USAT (60 at IHR and 15 at HR). The median time delay from symptoms to USAT was 5 days. Ultrasound-assisted thrombolysis resulted in improvements in tricuspid annular plane systolic excursion; pulmonary artery (PA) systolic and mean pressures; Qanadli score; right to left ventricle diameter ratio and right to left atrial diameter ratio; and diameters of main, right, and left PA regardless of the baseline risk status ( P < .0001 for all). Death was documented in 4 patients, and major and minor bleeding were noted in 2 and 5 of the patients, respectively. No PE-related event was noted during postdischarge follow-up period of median 310 days. Our study revealed that USAT facilitates the resolution of PA thrombotic burden, recovery of pulmonary hemodynamics, and right heart functions with acceptable rates of procedure-related complications in patients with PE, irrespective of the IHR or HR status.

Catheter-Directed Treatment of Pulmonary Embolism: A Systematic Review and Meta-Analysis of Modern Literature

We summarize the evidence for the safety and efficacy of catheter-directed thrombolysis (CDT) with and without ultrasound-assisted therapy for treating submassive and massive pulmonary embolism (PE) in a systematic review. The primary efficacy outcome was mortality. Outcomes were pooled across studies with the random-effects model. Twenty-four studies enrolled 700 patients in total; 653 received mechanical thromboembolectomy treatments for PE (mortality rate, 9% [95% confidence interval (CI), 6%-13%], P = .12; rate of minor complications, 6% [95% CI, 2%-13%]). In the ultrasound-accelerated thrombolysis (USAT) studies, the mortality rate was 4% (95% CI, 1%-11%) and in the non-USAT studies, it was 9% (95% CI, 6%-13%). Secondary safety outcomes were all bleeding events, which occurred in 12% (95% CI, 7%-20%) of the USAT studies and in 10% (95% CI, 5%-20%) of the non-USAT studies. Current clinical evidence does not prove USAT is superior over CDT methods.

Treatment of Massive or Submassive Acute Pulmonary Embolism With Catheter-Directed Thrombolysis

The presentation of acute pulmonary thromboembolism (PE) can be highly variable resulting in diagnostic challenges and management difficulties. Current guidelines suggest that therapy must be adjusted based on the severity of PE presentation. Systemic thrombolysis is the standard therapy for acute massive PE; however, systemic thrombolysis carries an estimated 20% risk of major hemorrhage, including a 3% to 5% risk of hemorrhagic stroke. There are data supporting the use of catheter-directed therapy (CDT) in massive and submassive PE, but past studies have limited its use to patients in whom systemic thrombolysis has either failed or was contraindicated. There is a paucity of data comparing the efficacy of CDT compared to systemic thrombolysis in different risk groups. This review will summarize the available data on the techniques and indications and outcomes of CDT for acute PE.

Ultrasound Accelerated Thrombolysis May Be an Effective and Safe Treatment Modality for Intermediate Risk/Submassive Pulmonary Embolism

Pulmonary embolism (PE) is a potentially life-threatening condition and the fact that 90% of PE originate from lower limb veins highlights the significance of early detection and treatment of deep vein thrombosis. Massive/high risk PE involving circulatory collapse or systemic arterial hypotension is associated with an early mortality rate of approximately 50%, in part from right ventricular (RV) failure. Intermediate risk/submassive PE, on the other hand, is defined as PE-related RV dysfunction, troponin and/or B-type natriuretic peptide elevation despite normal arterial pressure. Without prompt treatment, patients with intermediate risk PE may progress to the massive category with a potentially fatal outcome. In patients with PE and right ventricular dysfunction (RVD), in hospital mortality ranges from 5% to 17%, significantly higher than in patients without RVD.

Alteplase for the Treatment of Pulmonary Embolism: A Review

Pulmonary embolism can present with a wide range of symptoms, from asymptomatic to cardiac arrest, making diagnosis challenging. Alteplase is a fibrinolytic that is indicated for the treatment of pulmonary embolism in intermediate- and high-risk patients. Controversy exists as to the patient population that will benefit most from fibrinolytic therapy, as well as the proper dose and administration technique. The patient's risk of bleeding should be weighed against the potential benefits of treatment in light of the clinical presentation because of the high mortality rate associated with pulmonary embolism. Nurses at the bedside must monitor for signs of bleeding when alteplase is administered. Fibrinolytic therapy will frequently be started in the emergency department, and the nurse must ensure that alteplase is administered in a safe and effective manner. This review discusses the clinical evidence for alteplase in pulmonary embolism and its specific role in treatment.

Alteplase treatment of acute pulmonary embolism in the intensive care unit

Acute pulmonary embolism accounts for 50 000 to 100 000 deaths each year in the United States. Because of the wide spectrum of clinical manifestations, ranging from massive pulmonary embolism to small peripheral emboli, stratifying and treating patients according to their signs and symptoms is important when an acute embolism is suspected. Patients' clinical findings can range from no signs or symptoms to unstable hemodynamic status and shock. The 3-month mortality is 10% to 15%, but can be as high as 60% in patients with hemodynamic shock. This article reviews the classifications of acute peripheral emboli, explains the treatment of acute peripheral emboli, reviews the pharmacology of alteplase, and presents an assessment of the literature evaluating alteplase for the treatment of acute peripheral emboli. Clinical pearls for the administration, monitoring, and care of a patient receiving alteplase in an intensive care unit also are discussed.

Fixed low-dose ultrasound-assisted catheter-directed thrombolysis for intermediate and high-risk pulmonary embolism

AIMS

No standardized local thrombolysis regimen exists for the treatment of pulmonary embolism (PE). We retrospectively investigated efficacy and safety of fixed low-dose ultrasound-assisted catheter-directed thrombolysis (USAT) for intermediate- and high-risk PE.

METHODS AND RESULTS

Fifty-two patients (65 ± 14 years) of whom 14 had high-risk PE (troponin positive in all) and 38 intermediate-risk PE (troponin positive in 91%) were treated with intravenous unfractionated heparin and USAT using 10 mg of recombinant tissue plasminogen activator per device over the course of 15 h. Bilateral USAT was performed in 83% of patients. During 3-month follow-up, two [3.8%; 95% confidence interval (CI) 0.5-13%] patients died (one from cardiogenic shock and one from recurrent PE). Major non-fatal bleeding occurred in two (3.8%; 95% CI, 0.5-13%) patients: one intrathoracic bleeding after cardiopulmonary resuscitation requiring transfusion, one intrapulmonary bleeding requiring lobectomy. Mean pulmonary artery pressure decreased from 37 ± 9 mmHg at baseline to 25 ± 8 mmHg at 15 h (P < 0.001) and cardiac index increased from 2.0 ± 0.7 to 2.7 ± 0.9 L/min/m(2) (P < 0.001). Echocardiographic right-to-left ventricular end-diastolic dimension ratio decreased from 1.42 ± 0.21 at baseline to 1.06 ± 0.23 at 24 h (n = 21; P < 0.001). The greatest haemodynamic benefit from USAT was found in patients with high-risk PE and in those with symptom duration < 14 days.

CONCLUSION

A standardized catheter intervention approach using fixed low-dose USAT for the treatment of intermediate- and high-risk PE was associated with rapid improvement in haemodynamic parameters and low rates of bleeding complications and mortality.

Successful pharmacomechanical intervention with ultrasonic-accelerated thrombolytic catheter for massive pulmonary embolism

An 86-year-old male with history of metastatic prostate carcinoma and hypertension was admitted due to acute onset dyspnea and lower extremity pain and swelling. Transthoracic echocardiography revealed a large right atrial thrombus extending in to the right ventricle. Within 12 h, the patient developed severe hypoxemia, tachypnea with sustained hypotension and cardiogenic shock due to presumed massive pulmonary embolism. The patient underwent emergency pulmonary angiography which showed large emboli in the right main pulmonary artery extending in to the middle and lower lobe branches. An ultrasonic-accelerated thrombolytic catheter was placed in the right main pulmonary artery for continuous infusion of alteplase for 20 h. Repeat pulmonary angiogram showed resolution of the large pulmonary emboli, with normal flow in to the distal pulmonary arteries. Significant improvement of hemodynamics, symptoms and hypoxemia occurred as well.

Massive pulmonary embolism

Massive pulmonary embolism (PE) is a potentially lethal condition, with death usually caused by right ventricular (RV) failure and cardiogenic shock. Systemic thrombolysis (unless contraindicated) is recommended as the first-line treatment of massive PE to decrease the thromboembolic burden on the RV and increase pulmonary perfusion. Surgical pulmonary embolectomy or catheter-directed thrombectomy should be considered in patients with contraindications to fibrinolysis, or those with persistent hemodynamic compromise or RV dysfunction despite fibrinolytic therapy. Critical care management predominantly involves supporting the RV, by optimizing preload, RV contractility, and coronary perfusion pressure and minimizing afterload. Despite these interventions, mortality remains high.

Thrombolytic therapy in acute pulmonary embolism

PURPOSE OF REVIEW

The goal of this review is to offer an overview of the use of thrombolytic therapy in acute pulmonary embolism. Clinicians including internists, surgeons, pulmonologists, and other specialists continue to face decisions regarding massive and submassive acute pulmonary embolism in their daily routines. Although an evidence base exists, unanswered questions remain regarding the use of thrombolytic agents.

RECENT FINDINGS

Few large, randomized trials exist in this area of medicine and unanswered questions remain. However, guidelines have been modified and new guidelines have been published over the past several years. Recent data indicating that lower doses of tissue plasminogen activator may be effective and safer are discussed. Newer thrombolytic agents may have advantages, but are less well studied.

SUMMARY

Thrombolytic therapy results in the accelerated lysis of acute pulmonary embolism. However, because nonpathologic thrombi are also lysed, these drugs, although potentially lifesaving, can cause significant bleeding complications. Massive acute pulmonary embolism is the clearest indication for the administration of thrombolytic agents, but patients with acute pulmonary embolism and significant compromise in the absence of hypotension may also merit consideration.

Moderate pulmonary embolism treated with thrombolysis (from the "MOPETT" Trial)

The role of low-dose thrombolysis in the reduction of pulmonary artery pressure in moderate pulmonary embolism (PE) has not been investigated. Because the lungs are very sensitive to thrombolysis, we postulated that effective and safe thrombolysis might be achieved by a lower dose of tissue plasminogen activator. The purpose of the present study was to evaluate the role of this "safe dose" thrombolysis in the reduction of pulmonary artery pressure in moderate PE. During a 22-month period, 121 patients with moderate PE were randomized to receive a "safe dose" of tissue plasminogen activator plus anticoagulation (thrombolysis group [TG], n = 61 patients) or anticoagulation alone (control group [CG], n = 60). The primary end points consisted of pulmonary hypertension and the composite end point of pulmonary hypertension and recurrent PE at 28 months. Pulmonary hypertension and the composite end point developed in 9 of 58 patients (16%) in the TG and 32 of 56 patients (57%) in the CG (p <0.001) and 9 of 58 patients (16%) in the TG and 35 of 56 patients (63%) in the CG (p <0.001), respectively. The secondary end points were total mortality, the duration of hospital stay, bleeding at the index hospitalization, recurrent PE, and the combination of mortality and recurrent PE. The duration of hospitalization was 2.2 ± 0.5 days in the TG and 4.9 ± 0.8 days in the CG (p <0.001). The combination of death plus recurrent PE was 1 (1.6%) in TG and 6 (10%) in the CG (p = 0.0489). No bleeding occurred in any group, and despite a positive trend in favor of a "safe dose" thrombolysis, no significant difference was noted in the rate of individual outcomes of death and recurrent PE when assessed independently. In conclusion, the results from the present prospective randomized trial suggests that "safe dose" thrombolysis is safe and effective in the treatment of moderate PE, with a significant immediate reduction in the pulmonary artery pressure that was maintained at 28 months.

Management of pulmonary embolism with rheolytic thrombectomy

BACKGROUND

Catheter thrombectomy combining thrombus destruction with local thrombolysis has been used in patients with pulmonary embolism (PE) who are unstable or have significant right heart dysfunction, but have contraindications to systemic thrombolytic therapy.

OBJECTIVES

To assess the outcomes of patients who underwent pulmonary embolectomy using a commercially available thrombectomy device.

METHODS

A retrospective chart review of patients who underwent pulmonary embolectomy between March 2007 and August 2009 was performed. Patients were classified as having clinical massive or submassive PE, and moderate or severe right ventricular dysfunction. Data collected included pre- and postprocedure shock index (heart rate divided by systolic blood pressure) and mean pulmonary artery pressure.

RESULTS

Sixteen patients with a mean (± SD) age of 54.4 ± 15.8 years underwent embolectomy. Five had clinical massive PE (two in cardiogenic shock) and three of 11 submassive cases had severe right ventricular dysfunction. All were deemed to have contraindications to systemic lysis. Both shock index (1.02 ± 33 preintervention versus 0.71 ± 0.2 postintervention [P=0.001]) and mean pulmonary artery pressure (34.5 ± 9.9 mmHg preintervention versus 27.1 ± 7.1 postintervention [P=0.01]) improved. In the massive PE group, one patient died and two survivors experienced retroperitoneal bleeding and transient renal failure. At follow-up (17.3 ± 7.8 months), two patients in the massive PE group demonstrated evidence of mild cor pulmonale.

CONCLUSION

Rheolytic thrombectomy is an effective strategy in managing massive PE, particularly in patients who have well-defined contraindications to systemic lytic therapy. The effectiveness of rheolytic thrombectomy for submassive PE is not as well defined, but warrants a comparison with systemic lytic therapy.

Advances in the diagnosis and treatment of acute pulmonary embolism

Over the past two decades, considerable progress in technology and clinical research methods have led to advances in the diagnosis, treatment and prevention of acute venous thromboembolism. Despite this, however, the diagnosis is still often missed and preventive methods are often ignored. Published guidelines are useful, but are limited by the existing evidence base so that controversies remain with regard to topics such as duration of anticoagulation, indications for placement and removal of inferior vena caval filters, and when and how to administer thrombolytic therapy. The morbidity and mortality of this disease remain high, particularly when undiagnosed. While preventive approaches remain crucial, the focus of this review is on the diagnostic and therapeutic approach to acute venous thromboembolism, with an emphasis on acute pulmonary embolism.

Aggressive management of pulmonary embolism

Pulmonary embolism (PE) and deep vein thrombosis are two elements of the same pathophysiological process referred to as venous thromboembolism. PE occurs when a thrombus migrates from a deep vein to the pulmonary arteries. Although the true incidence of PE is not known, it is estimated that 530,000 cases of PE occur annually in the United States. Clinical presentation varies from asymptomatic (incidentally diagnosed) to fatal. Development of symptoms depends on the embolic burden and the severity of any underlying cardiopulmonary disease. Several treatment options are available for patients diagnosed with PE. The mainstay of treatment is anticoagulation, but given the high mortality associated with some presentations of symptomatic PE, some advocate more aggressive therapy. In this article we discuss such therapies and their potential and appropriate use.

Endovascular therapy for acute pulmonary embolism

Acute pulmonary embolism (PE) is the third most common cause of death among hospitalized patients. Treatment escalation beyond anticoagulation therapy is necessary in patients with massive PE (defined by hemodynamic shock) as well as in many patients with submassive PE (defined by right ventricular strain). The best current evidence suggests that modern catheter-directed therapy to achieve rapid central clot debulking should be considered as an early or first-line treatment option for patients with acute massive PE; and emerging evidence suggests a catheter-directed thrombolytic infusion should be considered as adjunctive therapy for many patients with acute submassive PE. This article reviews the current approach to endovascular therapy for acute PE in the context of appropriate diagnosis, risk stratification, and management of acute massive and acute submassive PE.

Minimally invasive evacuation of spontaneous intracerebral hemorrhage using sonothrombolysis

OBJECT

Catheter-based evacuation is a novel surgical approach for the treatment of brain hemorrhage. The object of this study was to evaluate the safety and efficacy of ultrasound in combination with recombinant tissue plasminogen activator (rt-PA) delivered through a microcatheter directly into spontaneous intraventricular (IVH) or intracerebral (ICH) hemorrhage in humans.

METHODS

Thirty-three patients presenting to the Swedish Medical Center in Seattle, Washington, with ICH and IVH were screened between November 21, 2008, and July 13, 2009, for entry into this study. Entry criteria included the spontaneous onset of intracranial hemorrhage ≥ 25 ml and/or IVH producing ventricular obstruction. Nine patients (6 males and 3 females, with an average age of 63 years [range 38-83 years]) who met the entry criteria consented to participate and were entered into the trial. A ventricular drainage catheter and an ultrasound microcatheter were stereotactically delivered together, directly into the IVH or ICH. Recombinant tissue plasminogen activator and 24 hours of continuous ultrasound were delivered to the clot. Gravity drainage was performed. In patients with IVHs, 3 mg of rt-PA was injected; in patients with intraparenchymal hemorrhages, 0.9 mg of rt-PA was injected. The rt-PA was delivered in 3 doses over 24 hours.

RESULTS

All patients had significant volume reductions in the treated hemorrhage. The mean percentage volume reduction after 24 hours of therapy, as determined on CT and compared with pretreatment stability scans, was 59 ± 5% (mean ± SEM) for ICH and 45.1 ± 13% for IVH (1 patient with ICH was excluded from analysis because of catheter breakage). There were no intracranial infections and no significant episodes of rebleeding according to clinical or CT assessment. One death occurred by 30 days after admission. Clinical improvements as determined by a decrease in the National Institutes of Health Stroke Scale score were demonstrated at 30 days after treatment in 7 of 9 patients. The rate of hemorrhage lysis was compared between 8 patients who completed treatment, and patient cohorts treated for IVH and ICH using identical doses of rt-PA and catheter drainage but without the ultrasound (courtesy of the MISTIE [Minimally Invasive Surgery plus T-PA for Intracerebral Hemorrhage Evacuation] and CLEAR II [Clot Lysis Evaluating Accelerated Resolution of Intraventricular Hemorrhage II] studies). Compared with the MISTIE and CLEAR data, the authors observed a faster rate of lysis during treatment for IVH and ICH in the patients treated with sonolysis plus rt-PA versus rt-PA alone.

CONCLUSIONS

Lysis and drainage of spontaneous ICH and IVH with a reduction in mass effect can be accomplished rapidly and safely through sonothrombolysis using stereotactically delivered drainage and ultrasound catheters via a bur hole. A larger clinical trial with catheters specifically designed for brain blood clot removal is warranted.