Thrombolysis Using the EKOS™ System: A New Improvement for Treating Blood ClotsMarch 12, 2021
The topic, “Intravascular Ultrasound Assisted Thrombolysis” was brought up at the September 10, 2019 Coordination and Maintenance Committee meeting. The issue presented was that, at the time, no ICD-10-PCS code or code combination was available to fully describe intravascular ultrasound assisted thrombolysis with tissue plasminogen activator (tPA).
Here is the link to the meeting minutes. For this topic, go to page 25. https://www.cms.gov/Medicare/Coding/ICD10/Downloads/2019-ICD10-Sep-Agenda.pdf
Related to this issue, it was noted that the Food and Drug Administration (FDA) approved the EKOS™ EkoSonic® Endovascular System (EKOS™ system) for use in the peripheral vasculature in 2003. FDA approval for the EKOS™ system use in the treatment of pulmonary embolism (PE) was obtained in 2014.
- Thrombosis: A blood clot in an artery or a vein that reduces the flow of blood through the vessel. Blood clots are made up of platelets and protein strands called fibrin.
- A deep vein thrombosis (DVT) is a thrombosis that has formed in a deep vein of the body, usually a lower leg or thigh.
- Clots in arteries have a different composition than clots in veins. Clots in arteries are mostly made up of platelets. Clots in veins are mostly made up of fibrin.
- Embolism: A condition that occurs when a piece or portion of a blood clot, foreign object, or other bodily substance moves through the vessels until it reaches a point within a vessel where it cannot pass. It becomes stuck in a blood vessel and largely obstructs the flow of blood, which is referred to as an occlusion.
- While a PE may be caused by fat, tumor tissue, or air bubbles, it is most commonly caused by a venous thrombosis.
- Thromboembolism, venous thromboembolism (VTE), thromboembolis: These terms refer to a reduction in blood flow (occlusion) that’s specifically caused by an embolism from a blood clot.
Of Note: DVTs can lead to PEs.
Treatment of DVT and PE
Therapeutic interventions for these DVTs and PEs include anticoagulation, thrombolytics, and surgical thrombectomy.
Unless contraindicated, anticoagulants are standard treatment for all PE and DVT cases. Anticoagulants are effective in limiting additional thrombus formation, but they do little to remove an existing thrombus. Two commonly used anticoagulants are heparin and warfarin.
Thrombolytics are generally used for more severe, submassive, and massive cases. Massive PEs, which can be immediately life-threatening, are often treated by surgical thrombectomy.
Thrombolytic drugs dissolve blood clots by activating plasminogen, which forms a cleaved product called plasmin.
- A cleaved product is a substance resulting from the splitting of a molecule into two or more simpler molecules.
Plasmin, a proteolytic enzyme (also called protease, proteinase, or peptidase), refers to a group of enzymes that are capable of breaking cross-links between the fibrin molecules, which provide the structural integrity of blood clots, thereby dissolving the blood clots. Because of these actions, thrombolytic drugs are also called “plasminogen activators” and “fibrinolytic drugs.”
There are three major classes of fibrinolytic drugs:
- tissue plasminogen activator (tPA)
- streptokinase (SK)
- urokinase (UK)
While drugs in these three classes all have the ability to effectively dissolve blood clots, they differ in their detailed mechanisms in ways that alter their selectivity for fibrin clots.
- Derivatives of tPA are the most commonly used thrombolytic drugs.
Tissue plasminogen activator dissolves blood clots through the following sequence:
- tPA binds to fibrin on the surface of the clot
- Activates fibrin-bound plasminogen
- Plasmin is cleaved from the plasminogen associated with the fibrin
- Fibrin molecules are broken apart by the plasmin and the clot dissolves
Fun fact: tPA was developed from an engineered Chinese hamster ovary (CHO) cell line.
Because thrombolytic drugs pose a risk of serious bleeding, the amount administered is minimized – a lower dose preferable to a higher dose. Administering a thrombolytic systemically has a higher risk of serious bleeding than administering it using a lower dose of the thrombolytic directly to the clot through catheter-directed thrombolysis (CDT).
“Conventional” CDT generally relies on a multi-side hole catheter placed adjacent to the thrombus through which thrombolytics are delivered directly to the thrombus.
Advantages of the EKOS™ system
As presented at the September 2019 Coordination and Maintenance Committee meeting, a newer method, such as the one utilized in the EKOS™ system, employs ultrasound to assist thrombolysis. Of note, “the ultrasound does not itself dissolve the thrombus, but pulses of ultrasonic energy temporarily make the fibrin in the thrombus more porous and increase fluid flow within the thrombus.”
“High frequency, low intensity ultrasonic waves create a pressure gradient that drives the thrombolytic into the thrombus and keeps it in close proximity to the binding sites. The most common indication for ultrasound assisted thrombolysis is the treatment of pulmonary embolism (about 68 % according to the manufacturer’s data). However, this therapy is also indicated for use in treating DVT and peripheral arterial occlusion (PAO).”
According to the requestor (the EKOS™ system is manufactured by Boston Scientific), results from internal investigations have shown that intravascular ultrasound assisted thrombolysis using the EKOS™ system:
- Speeds time to clot dissolution, increases clot removal, and enhances clinical improvement compared to either conventional CDT or thrombectomy.
- Improves clearance of clots by comparison to conventional CDT. This is in part attributable to 48 percent greater drug absorption within 1 hour, and 84 percent greater drug absorption within 2 hours.
- Lowers the risk of bleeding and other complications.
- Requires smaller doses of thrombolytics, minimizing risk from bleeding.
“The EKOS™ system reduces dosage requirements by as much as 68 percent compared to conventional CDT. It requires up to four times less drug dosage than typically used in systemic delivery.”
This site and reference, from Boston Scientific, explains and depicts the EKOS™ system device components: https://www.bostonscientific.com/en-US/products/thrombectomy-systems/ekosonic-endovascular-system/control-unit.html
Below is a close-up of the infusion catheter. The three arrows on the top are pointing to where the tPA is administered from the catheter to the thrombus. The one bottom arrow points to the ultrasound core. The ultrasound core delivers high-frequency, low energy intravascular ultrasound along the entire treatment zone.
This site shows a video of the procedure itself and how the EKOS™ system works: https://www.dicardiology.com/videos/video-how-ekos-thrombolytic-technology-works-dissolve-clots
Coding the Procedures for Intravascular Ultrasound Assisted Thrombolysis with Tissue Plasminogen Activator (tPA) using the EKOS™ System
The Root Operation is always “Fragmentation.”
The definition for the Root Operation “Fragmentation” provided in the 2013 ICD-10-PCS Reference Manual is, “Breaking solid matter in a body part into pieces.”
The explanation provided is that the physical force applied directly or indirectly is used to break the solid matter into pieces. The solid matter may be an abnormal byproduct of a biological function or a foreign body. The pieces of solid matter are not taken out. Fragmentation is the Root Operation used for procedures to break up, but not remove, solid material, such as a thrombus or embolism.
Of Note: Do not confuse the Root Operation “Fragmentation” with the Root Operation “Extirpation.” The definition for the root operation Extirpation provided in the 2013 ICD-10-PCS Reference Manual is, “Taking or cutting out solid matter from a body part.” These Root Operations cannot be coded together as they are mutually exclusive.
New and Revised PCS Tables with the Root Operation “Fragmentation”
Three new Tables with the Root Operation “Fragmentation” were added to the Body System Tables of the Upper Arteries, Lower Arteries, Upper Veins and Lower Veins; Tables 03F, 04F, and 05F.
Additional “Body Parts” were added to Table 02F, Pulmonary Trunk, Pulmonary Artery Right and Left, Pulmonary Vein Right and Left. Body Part “Pericardium” was the only Body Part in this Table prior to FY2021.
- The three new Tables and additions to Table 02F resulted in 116 new codes, effective October 1, 2020.
- All of the resulting new PCS codes have the Approach character “3” for Percutaneous.
- Since the EKOS system device is never left in the body following the conclusion of the procedure; the Device character reported is always “Z” for No Device.
- All of the resulting new PCS codes have, as the Qualifier character, either “Z” for No Qualifier, or “0” Ultrasonic. The EKOS system always uses ultrasound. The Qualifier character is always reported as “0” when the EKOS system is used.
Coding Scenario: A patient was diagnosed with a single thrombus of the left subclavian vein. The procedure performed was a percutaneous thrombolysis of the left subclavian vein thrombus using an EKOS device to deliver tPA directly to the thrombus with ultrasonic assistance.
The PCS codes reported are:
05F63Z0 – Fragmentation of Left Subclavian Vein, Percutaneous Approach, Ultrasonic
6A750Z7 – Ultrasound therapy of other vessels, single
3E03317 – Introduction of Other Thrombolytic into Peripheral Vein, Percutaneous Approach
The Boston Scientific website contains an easy to use reference guide,”… an overview of the coding, coverage and payment landscape for the EKOS™ EkoSonic® Endovascular System.” This guide provides the PCS codes and FY 2021 MS-DRG information, and the CPT codes and CY 2020 RVU information. https://www.bostonscientific.com/content/dam/bostonscientific/Reimbursement/peripheral-intervention/pdf/EKOS_Procedure_Coding_and_Reimbursement_Guide.pdf
Here are Tables 02F, 03F, 04F, 05F and 06F. The changes are highlighted in yellow. See also the notations to the left of each Table. All of the Tables that have been changed for FY2021 can be located on the CMS.gov website. Go to https://www.cms.gov/medicare/icd-10/2021-icd-10-pcs. Click on 2021 ICD-10-PCS Addendum (ZIP) to download the file.
Three new Tables and additions to Table 02F resulted in 116 new codes, effective October 1, 2020.
Prior to October 1, 2020, there was no ICD-10-PCS code or code combination available to fully describe intravascular ultrasound assisted thrombolysis with tissue plasminogen activator (tPA).
The EKOS™ system, employs ultrasound to assist thrombolysis. High frequency, low intensity ultrasonic waves create a pressure gradient that drives the thrombolytic (tPA) into the thrombus.
The EKOS™ system is used to treat pulmonary embolisms, and arterial and/or venous thrombosis.
The Root Operation for EKOS™ system procedures is always “Fragmentation.”