Mechanical Power Aspiration With CAT RX and Indigo® System: Innovation in Coronary Thrombus Removal

Acute coronary syndrome (ACS) encompasses a spectrum of conditions caused by acute myocardial ischemia and/or infarction that is due to a reduction in coronary blood flow. Myocardial infarction (MI) is a severe sub-category of ACS where the ischemia leads to cardiac tissue damage and release of cardiac-specific biomarkers.¹ Myocardial damage in MI is typically precipitated by atherosclerotic plaque disruption and coronary thrombus formation, leading to reduced or completely eliminated blood flow to the heart muscle.¹ MI is among the leading cause of morbidity and mortality in the U.S. resulting in >$12 billion annually in hospitalization costs.²
 

Rapid myocardial reperfusion is the main treatment goal in MI. First introduced in the 1970s, percutaneous coronary intervention (PCI) has evolved into one of the primary treatment modalities for MI, with the benefits of PCI greatly outweighing the risks.³ These benefits have been well established by multiple clinical trials.³
 

Clinical evidence has shown that manual aspiration thrombectomy is capable of removing thrombotic material from occluded coronary arteries. This results in establishment of TIMI 3 flow and possibly preventing no-reflow phenomenon.^3,4 Early evidence suggested a reduction in major adverse cardiovascular events, although larger randomized clinical trials using routine aspiration for all MI patients were unable to confirm those results.^5,6,7 All prior studies included use of manual aspiration thrombectomy which utilized small volume (e.g., 30 cc) syringes. Manual aspiration suffers from decreased aspiration force as the syringe fills with fluid. With inconsistent vacuum, there is decreased efficacy and a potential for systemic embolization during catheter removal. This phenomenon was reported in the TOTAL trial in 2015 and led to a decline in the use of aspiration thrombectomy in ACS PCI.⁶ Sub group analysis exploring the high thrombus burden subset of patients highlighted the potential of improved outcomes. This motivated further innovation in the field of coronary aspiration.⁶
 

One major limitation of PCI without aspiration for ACS is microvascular obstruction of the infarct related artery due to downstream embolization of thrombotic material.⁴ PCI with aspiration thrombectomy has been regaining increased attention as a way to prevent or reduce embolization of atherothrombotic debris during PCI.³

Indigo System With CAT RX Coronary Aspiration Catheter
 

The aim of mechanical-power thrombus aspiration is to deliver consistent suction throughout the aspiration cycle in order to maximize efficiency of thrombus removal (Figure 1).* Removing thrombus from hard-to-reach vessels requires a highly deliverable, atraumatic catheter. Mechanical-power aspiration is an established technique commonly used in the neurovascular space for thrombus removal in acute ischemic stroke. In 2012, Penumbra revolutionized acute stroke therapy with the Penumbra System, enabling reperfusion of cerebrovascular occlusions. In 2015, Penumbra launched the Indigo System to remove thrombus in peripheral arterial occlusions. Now Penumbra has adapted the neuro-tracking technology of these catheters and mechanical power aspiration systems to address the limitations of traditional aspiration thrombectomy for the coronaries by the development of the CAT RX system.
 

As an analysis of our early experience, we retrospectively collected data from four institutions around the country.⁸ Of the fifty-nine patients analyzed, 76.3% had TIMI 0 flow pre-procedure and 93.2% had TIMI 3 flow post-CAT RX. Median aspiration time with CAT RX was 35 seconds and there was no incidence of stroke.
 

Two case examples demonstrating mechanical power aspiration with the CAT RX aspiration catheter are displayed on the next page. [Editor's note: to view the cases, please download the PDF of this article - located beneath the title.]

Conclusions
 

Data presented at the American College of Cardiology (ACC) Scientific Sessions showed initial safety and efficacy for the CAT RX mechanical power aspiration catheter for thrombus removal in acute MI patients.⁸ These results are very encouraging8 and CAT RX has now been used in over 5000* patients with acute coronary syndrome. Other potential advantages we have observed are a reduction in use of glycoprotein IIb/IIIa inhibitors (which may lead to higher rates of bleeding) and improved thrombus aspiration may define stent length more accurately. Both of which may reduce cost of care significantly. We are beginning to enroll in a 400 patient prospective observational trial, CHEETAH, which will evaluate initial safety and collect performance data on Penumbra’s Indigo Aspiration System with the CAT RX Aspiration Catheter. CHEETAH will focus on patients with high thrombus burden (TIMI thrombus grade 4 or 5) using CAT RX frontline. We expect the results to further refine our technique of thrombus aspiration and fine tune the utilization of the CAT RX for patients with high thrombus burden.

¹Manatee Memorial Hospital, Bradenton, Florida; ²St. Joseph Hospital, Orange, California; ³Florida Hospital, Tampa, Florida; ⁴Smidt Heart Institute at Cedars Sinai Medical Center, Los Angeles, California

This article is sponsored by Penumbra, Inc.

Disclosures: Dr. Mathews, Dr. Kolski, and Dr. Dohad report receiving honoraria from Penumbra.

Disclaimer: The opinions and clinical experiences presented herein are for informational purposes only. The results may not be predictive of all patients. Individual results may vary depending on a variety of patient-specific attributes. *Data on file at Penumbra, Inc. **Tests performed and data on file at Penumbra, Inc. Bench test results may not be indicative of clinical performance.
 

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