EKOS Catheter Directed Thrombolysis - Protocol, Setup, Procedure, Success Rate, Indications & Guidelines

Content:

• What is EKOS Catheter Directed Thrombolysis?
• EKOS Protocol
• EKOS Setup
• EKOS Procedure
• EKOS Success Rate
• EKOS Indications
• EKOS Guidelines

What is EKOS Catheter Directed Thrombolysis?

EKOS Catheter Directed Thrombolysis (EKOS CDT) is an ultrasound-assisted catheter-directed thrombolysis technique used to dissolve blood clots in selected patients with pulmonary embolism (PE), deep vein thrombosis (DVT), and certain arterial thrombotic conditions. The EKOS™ Endovascular System combines a specialized infusion catheter with low-power, high-frequency ultrasound energy. The ultrasound helps separate fibrin strands within the clot, allowing thrombolytic medications such as alteplase (tPA) to penetrate more effectively. Unlike systemic thrombolysis, where the medication circulates throughout the body, EKOS delivers the drug directly into the clot, allowing lower thrombolytic doses while aiming to reduce systemic bleeding complications.

The procedure is performed in an interventional radiology, vascular surgery, or cardiac catheterization laboratory by trained specialists. It has become an important treatment option for carefully selected patients who require more than anticoagulation alone but may have an increased bleeding risk with full-dose systemic thrombolysis. Although EKOS has shown improvements in right ventricular function and clot burden in many studies, patient selection remains essential because not every patient with PE or DVT requires catheter-directed thrombolysis. Modern treatment decisions are typically made by multidisciplinary Pulmonary Embolism Response Teams (PERT) or vascular specialists after reviewing imaging, hemodynamic status, bleeding risk, and overall clinical condition.

EKOS Protocol

The EKOS protocol begins with careful patient assessment and confirmation of the diagnosis using CT pulmonary angiography for pulmonary embolism or duplex ultrasound and venography for deep vein thrombosis. Baseline laboratory investigations include complete blood count, coagulation profile, renal function, fibrinogen level, and cardiac biomarkers when pulmonary embolism is suspected. Intravenous unfractionated heparin is usually continued at an adjusted therapeutic dose during the procedure because it prevents further clot formation while the thrombolytic medication dissolves the existing thrombus. Before treatment starts, physicians evaluate contraindications to thrombolysis, including recent surgery, active bleeding, hemorrhagic stroke, or uncontrolled hypertension.

Once the catheter has been positioned inside the thrombus, alteplase (tPA) is infused through the catheter while saline coolant simultaneously circulates around the ultrasound core. The exact infusion rate and duration vary according to institutional protocols, clot burden, and whether one or two catheters are used. Continuous monitoring includes blood pressure, oxygen saturation, ECG, neurological examinations, laboratory testing, and access-site evaluation. After completion of thrombolysis, repeat imaging and hemodynamic assessment determine treatment success and guide transition to standard anticoagulation therapy. Many centers follow standardized protocols to minimize complications while maximizing clot resolution.

EKOS Setup

Proper EKOS setup begins in a fully equipped catheterization or interventional radiology suite. Sterile preparation is essential before vascular access is obtained, usually through the common femoral vein or occasionally the internal jugular vein for pulmonary embolism treatment. After guidewire placement, the physician advances the EKOS Intelligent Drug Delivery Catheter into the affected pulmonary artery or thrombosed vein under fluoroscopic guidance. Once correctly positioned, the removable ultrasound core is inserted into the catheter. The catheter is then connected to separate infusion pumps for thrombolytic medication and coolant solution while also attaching the ultrasound control console.

The EKOS control unit continuously delivers low-energy ultrasound throughout the infusion period. Nursing staff verify infusion pump settings, catheter position, and proper coolant flow before activating ultrasound. Continuous ECG monitoring, pulse oximetry, blood pressure measurement, and regular neurological assessments remain standard throughout therapy. Because treatment often continues for several hours, patients are generally admitted to an intensive care or monitored setting until thrombolysis has been completed and the catheter safely removed. Proper equipment setup significantly contributes to both treatment effectiveness and patient safety.

EKOS Procedure

The EKOS procedure starts with ultrasound-guided venous access followed by insertion of a vascular sheath. Diagnostic angiography is performed to identify the exact location and extent of the thrombus. A guidewire is advanced across the clot, and the EKOS infusion catheter is carefully positioned within the thrombus. Once the catheter is in place, the ultrasound core is inserted and connected to the console. Alteplase infusion begins simultaneously with saline coolant circulation while ultrasound energy is activated. Throughout treatment, patients are monitored closely for bleeding, oxygenation, blood pressure changes, and improvement in symptoms.

Treatment duration commonly ranges from several hours to approximately one day depending on institutional protocols and clot burden. After completion of thrombolysis, the ultrasound core and catheter are removed, manual or device-assisted hemostasis is achieved, and patients continue therapeutic anticoagulation. Follow-up imaging, echocardiography, or venography evaluates clot resolution and right ventricular recovery. Early mobilization, compression therapy for DVT when appropriate, and long-term anticoagulation planning complete the overall management strategy after EKOS therapy.

EKOS Success Rate

Clinical studies have demonstrated favorable outcomes with EKOS therapy in appropriately selected patients. Research involving intermediate-risk and high-risk pulmonary embolism has shown significant improvement in right ventricular function, pulmonary artery pressures, oxygenation, and symptom relief after ultrasound-assisted catheter-directed thrombolysis. In major clinical trials such as SEATTLE II, substantial reductions in right ventricular dilation were observed while using lower total doses of alteplase than systemic thrombolysis. Additional observational studies have reported successful restoration of blood flow with relatively low rates of major bleeding compared with historical systemic thrombolysis data.

Although reported success rates are generally high, outcomes depend on patient selection, clot burden, treatment timing, and operator experience. Current evidence suggests that EKOS improves surrogate outcomes such as right ventricular strain and clot resolution, but ongoing research continues to evaluate its long-term superiority over conventional catheter-directed thrombolysis or anticoagulation alone. Most professional societies recommend individualized decision-making rather than routine use for every pulmonary embolism patient.

EKOS Indications

EKOS catheter-directed thrombolysis is considered for carefully selected patients rather than all individuals with venous thromboembolism. Common indications include intermediate-high-risk pulmonary embolism with evidence of right ventricular dysfunction, selected patients with massive pulmonary embolism who remain stable enough for catheter-based intervention, extensive iliofemoral deep vein thrombosis with severe symptoms, phlegmasia cerulea dolens, and selected patients in whom rapid clot reduction is desired while attempting to reduce systemic thrombolytic exposure. Decisions are usually made after balancing expected benefits against bleeding risk.

Contraindications generally mirror those for thrombolytic therapy and include active bleeding, recent hemorrhagic stroke, intracranial neoplasm, major recent surgery, severe uncontrolled hypertension, and other conditions associated with unacceptable bleeding risk. Many hospitals use multidisciplinary PERT teams to evaluate each patient individually before recommending EKOS therapy. This collaborative approach helps identify patients most likely to benefit while avoiding unnecessary intervention in lower-risk cases.

EKOS Guidelines

Recent multidisciplinary pulmonary embolism guidelines recognize catheter-directed thrombolysis, including EKOS, as a reasonable treatment option for selected patients with acute pulmonary embolism who have evidence of right ventricular dysfunction or clinical deterioration despite anticoagulation. However, these recommendations emphasize that catheter-directed therapy should not routinely replace anticoagulation in low-risk pulmonary embolism. Instead, therapy should be individualized according to hemodynamic status, imaging findings, bleeding risk, and institutional expertise.

Current best practice recommends management within experienced centers capable of performing advanced endovascular procedures and providing continuous intensive monitoring. Institutions are encouraged to develop standardized EKOS protocols covering patient selection, anticoagulation management, thrombolytic dosing, catheter placement, laboratory monitoring, complication management, and follow-up care. As ongoing clinical trials continue to expand the evidence base, guideline recommendations are expected to evolve further, but careful multidisciplinary patient selection remains the cornerstone of successful EKOS catheter-directed thrombolysis.