Excimer Laser Atherectomy in Acute Myocardial Infarction-Evidence-based Treatment Approach

Excimer Laser Atherectomy in Acute Myocardial Infarction-Evidence-based Treatment Approach

Topaz On
US Cardiology 2004
Published: August 2004
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The last three years have seen the application of percutaneous excimer laser atherectomy in patients sustaining acute myocardial infarction (AMI) gaining momentum. Current efforts in the US are concentrated toward identification of the best technologies for efficacious restoration of flow in the infarct-related vessel 1 and toward shortening the time lag between the presentation of AMI patients to the emergency department and the subsequent percutaneous coronary intervention at the cardiac catheterization suite for revascularization of the infarct-related vessels.2 With this in mind, the interest of interventionalists and medical centers alike in excimer laser atherectomy as a reliable and efficient revascularization modality is justified.3,4

In August 2003, the US Food and Drug Administration (FDA) removed a decade-old set of contraindications for excimer laser use, that were originally imposed by the laser industry as a cautionary measure. Thus, the following clinical conditions are no longer considered contraindications and are currently available for the interventionalist discretions:AMI, acute thrombosis, and depressed left ventricular ejection fraction. The FDA decision and the noted growing recognition of the role of excimer laser atherectomy in AMI are based on discoveries from basic research projects that illuminate the special interaction of excimer laser with thrombus and on clinical evidence from numerous multicenter and single center studies that analyzed excimer laser utilization in coronary and peripheral revascularization.

Thrombolytic pharmacologic therapy and/or balloon angioplasty with adjunct stenting continue to be considered standard of care in the management of patients with Q-wave and non-Q-wave AMI alike.The pharmacologic approach is limited by restoration of adequate antegrade flow in only 50% to 60% of patients and by 20% to 30% post-treatment reocclusion of the infarct-related artery. Although balloon angioplasty has commonly and successfully been used in AMI, it carries significant limitations, especially in dealing with vessels and lesions that contain intracoronary thrombus. Since thrombus is highly prevalent in AMI, its presence within the infarct-related vessel is associated with a higher risk for complications during and after standard balloon angioplasty. Notably, thrombus disruption by balloon inflations or by direct stenting can increase local thrombosis, enhances platelet aggregation, and results in distal embolization. Hence, the application of 308nm ultraviolet pulsed-wave excimer laser energy is intriguing.This laser provides the following advantages:

• The laser system (CVX-300, Spectranetics) is a technically user-friendly device. It is readily available for urgent utilization in the cardiac catheterization suite, especially in AMI patients who are unstable and need rapid intervention.

• A new catheter technology5 (termed ‘optimal spacing’) that was introduced in 2001 provides a 30% increase in plaque ablation and thrombus dissolution in comparison with the previous generation of laser catheters.

• The emission of excimer light results in adequate thrombus removal and clearance,6–8 thus, contributing to rapid restoration of enhanced antegrade thrombolysis in myocardial infarction (TIMI) flow within the infarct-related vessel.

• The excimer laser energy is uniquely capable of suppression of platelets aggregation,9 significantly reducing the need for administration of expensive glycoprotein 2b/3a receptor inhibitors.

• The underlying atherosclerotic plaque is vaporized and debulked.

• The effective interaction of the excimer light with the thrombus and plaque eliminates the need to use distal protection devices, even in saphenous vein graft interventions.

• The laser facilitates subsequent stenting of the target lesion.

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References:
  1. Topaz O,“Focus on the infarct related artery: a thrombus runs through it”, Cath. Cardiovasc. Intervent. (2002), 57: pp. 340–341.
  2. Topaz O, Perin E C, Jesse R L, Mohanty P K, Carr M E and Rosenschein U, “Power thrombectomy in acute coronary syndromes”, Angiology (2003), 54: pp. 457–468.
  3. Topaz O, “The quest for laser thrombolysis”, Lasers Med. Science (2001), 16: pp. 232–235.
  4. Topaz O,“Excimer laser thrombolysis: an emerging option for acute ischemic coronary syndromes”, Lasers Med. Science (2001), 16: pp. 130–132.
  5. Topaz O, Lippincott R, Bellendis J,Taylor K and Reiser C, “‘Optimally spaced’ excimer laser coronary catheters: performance analysis”, J. Clin. Laser Med. Surg. (2001), 19: pp. 9–14.
  6. Topaz O, Bernardo N L, Shah R, McQueen R, Desai P, Janin Y, Lansky A J and Carr ME Jr, “Effectiveness of excimer laser coronary angioplasty in acute myocardial infarction or in unstable angina pectoris”, Am. J. Cardiol. (2001), 87: pp. 849–855.
  7. Topaz O, Shah R, Mohanty P K, McQueen R A, Janin Y and Bernardo N L,“Application of excimer laser angioplasty in acute myocardial infarction”, Laser Surg. Med. (2001), 29: pp. 185–192.
  8. Topaz O, Ebersole D, Das T, Alderman E L, Madyoon H,Vora K, Baker J D, Hilton D and Dahm J B, “Excimer laser angioplasty in acute myocardial infarction”,The CARMEL multicenter trial, Am. J. Cardiol. (2004), 93: pp. 694–701.
  9. Topaz O, Minisi A J, Bernardo N L, McPherson R A, Martin E, Carr S L and Carr M E Jr,“Alterations of platelet aggregation kinetics with ultraviolet laser emission: the “stunned platelet” phenomenon”, Thromb. Haemost. (2001), 86: pp. 1,087–1,093.
  10. Dahm J B,Topaz O,Woenckhaus C, Staudt A, Mox B, Hummel A and Felix S B, “Laser-facilitated thrombectomy: a new therapeutic option for treatment of thrombus-laden coronary lesions”, Cath. Cardiovasc. Intervent. (2002), 56: pp. 365–372.
  11. Topaz O, Minisi A J, Bernardo N L,Alimar R, Ereso A and Shah R,“Effectiveness of excimer laser angioplasty in patients with acute coronary syndromes in those with – versus – those without normal left ventricular ejection fraction”, Am. J. Cardiol. (2003), 91: pp. 797–802.
  12. Ebersole D, Dahm J B, Das T, Madyoon H, Vora K, Baker J, Hilton D, Alderman E and Topaz O, “Excimer laser revascularization of saphenous vein grafts in acute myocardial infarction”, J. Invas. Cardiol. (2004), 16: pp. 177–180.
  13. Topaz O, Minisi A J, Morris C, Mohanty P K and Carr M E Jr,“Photoacoustic fibrinolysis: pulsed-wave, mid-infrared laser-clot interaction”, J.Thrombosis Thrombolysis (1996), 3: pp. 209–214
  14. Topaz O, Morris C, Minisi A J, Mohanty P K and Carr M E Jr, “Enhancement of t-PA induced fibrinolysis with laser energy: in-vitro observations”, Lasers Med. Sci. (1999), 14: pp. 123–128.
  15. Topaz O, Ebersole D, Dahm J B, Das T, Madyoon H and Perin E C, “Excimer laser revascularization: current indications, applications and techniques”, Lasers Med. Sci. (2001), 16: pp. 72–77.

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