How to deal with thrombus in ACS "Zap it" - Laser for Thrombus Suneel Talwar Dorset Heart Centre Royal Bournemouth Hospital

Conflict of Interest Consultant/Advisory Board –Spectranetics Clinical & Research Grant Support –Boston Scientific Corporation –Cordis

- Photoablation is the use of light to vaporize and remove tissue Excimer Laser

 Photochemical  Photothermal  Photomechanical Breaking molecular bonds Producing thermal energy Creating kinetic energy Mechanism of Action Three distinct mechanisms of action contribute to Excimer Laser Photoablation

 UV light pulse hits tissue for 125 billionths of a second  50 microns penetration  Billions of molecular bonds fractured per pulse billionths of a second Photochemical Mechanism: Breaking Molecular Bonds

 Absorption creates molecular vibration in tissue  Vibration of molecules heats intracellular water  Water vaporizes, rupturing cells  Steam forms expanding vapor bubble Photothermal Mechanism: Producing thermal energy

 Expansion and collapse of vapor bubble breaks down tissue and clears by-products away from tip  By-products of ablation are water, gas, and small particles (90%<10 microns = size of red blood cell) 400 millionths of a second Photomechanical Mechanism: Creating kinetic energy

The Excimer wavelength is very close to what is used in eye surgery, indicative of its shallow depth of penetration and hence safety

Affinity for Photon Absorption The Excimer wavelength is ideally suited for absorption by the acute thrombus

The Antiplatelet Effects of Laser Energy

placebo 60mj 30mj The Laser inhibits platelet aggregation acting like a localized IIB IIIa Inhibitor

Am J Cardiol 2004;93:

The data obtained from the participating centres was submitted to independent core laboratories for quantitative coronary analysis and statistical analysis.

High risk patients included 30% of the patients had Diabetes 24% had previous CABG 23% had sustained a previous MI 28% had a contraindication to thrombolysis 13% presented to the cath lab with cardiogenic shock. The target vessel for revascularisation was an old saphenous vein graft in 21% of patients.

The greater amount of thrombus the better the result with the Laser

High flow rates post laser

The CARMEL Study-Complications Death6(4%) Laser Induced Perforation0 Laser Induced dissection6(4%) Acute closure1(0.6%) Laser induced no-flow1(0.6%) Stent induced no-flow1(0.6%) Groin bleeding complications3 (2%)

Study Summary Extended FAMILI Flow in Acute Myocardial Infarction Patients after Laser Intervention - Extended Pilot Study

Extended FAMILI Objective: To benchmark microvascular coronary blood flow in AMI patients after percutaneous intervention that includes excimer laser coronary atherectomy Study Design: Prospective non-randomized study in up to 20 sites, and up to 80 patients. Principal Investigators: Jeffrey Moses, MD Antonio Columbo, MD

EXTENDED FAMILI RESULTS Laser Success: Defined as TIMI 2-3 with > 20% reduction in %DS post laser. Procedure Success: Defined as TIMI 3 flow and < 50% DS on final angiogram without in-hospital MACE. - Laser Success: 94% - Procedure Success: 96% - 30 Day-MACE: 3% Low MACE correlated with the high Blush Scores

EXTENDED FAMILI

Svilaas T et al. N Engl J Med 2008;358: Thrombus Aspiration during Primary PCI: TAPAS study

Extended FAMILI: Conclusions –Laser appears safe for thrombus ablation in Acute MI: 30 Day MACE 3% –High Procedural Success Rate of 91% –Extended FAMILI appears equivalent in TIMI flow rates compared to other thrombectomy studies. –Blush scores post-procedure appear to be significantly better than the other thrombectomy studies..

TAAMI: Thrombus Ablation in Acute Myocardial Infarction Randomised controlled study comparing a Laser-Stent strategy to a Balloon-Stent strategy N= sites in Poland

TAAMI: Thrombus Ablation in Acute Myocardial Infarction Primary Endpoint -Complete ST resolution and MBG 3 immediately post procedure Secondary Endpoint -MACE 30 days -MBG -TIMI Flow rates post Laser -TIMI frame count -ST reolution at 60 minutes post procedure

Our Approach in AMI Turn on the Laser prior to arrival of patient in the Lab to avoid delays Laser Catheter: For most total occlusions start with a 0.9/1.4 catheter (both are 6F compatible) The laser will work over any wire The vapor bubble works best in a saline medium (blood and contrast must be flushed prior to lasing) Activate the laser a few mm proximal to the start of the lesion – to maximize the effect of the advancing vapor bubble –and to avoid cavitation into the plaque Use higher energies and rates from the start (60/40) – to create a larger vapor bubble – and lead to better inhibition of platelet aggregation In order to get the effect of the advancing vapor bubble, the laser catheter must be advanced very slowly (rate of <1mm per second)

Conclusion The use of the excimer laser is feasible and safe in the setting of an AMI Laser treatment has been shown to result in significant thrombus removal, suggesting direct laser energy absorption and thrombus vaporisation The potential clinical benefits of the stunned platelet phenomenon await clinical confirmation A prospective randomised multicentre comparing this to convention angioplasty and stenting as well as thrombectomy is necessary to confirm the observations made so far