Role of Adjunct devices in PCI

Dr Mahadeva Swamy BSR Cardiology, JIPMER

Adjunct devices in PCI Plaque modification

Cutting Balloon (CBA)

Laser (ELCA)

Atherectomy (DCA, PTRA)

Thrombectomy

EPD

Plaque modification Atheroablative devices during PCI → facilitate

procedural success and reduce restenosis

Plaque modification is valuable tool for treatment of complex lesions

Vessel pretreatment → larger MLD and lower TLR rate

Lesion pretreatment & plaque modification Regular balloon & stent do not adequately

address problems of plaque shift and resistant lesions

Lesion pretreatment is to facilitate procedural success and reduces restenosis

Mechanism:Minimizes plaque shifting

Decreases recoilOptimal stent expansion

Cutting balloon angioplasty (CBA) Cutting balloon – controlled longitudinal

incisions (atherotomy)

Improve luminal enlargement at lower pressure inflation

Improved acute results with less barotrauma → long term clinical benefit

Mechanism of action of CBA Controlled microincisions in atheroma at lower

pressure – reduced barotrauma

Better luminal enlargement at lower pressures

In calcified lesions, CBA achieves larger lumen gain

Cutting Balloons

Equipment Cutting balloons – 6, 10 & 15 mm

Atherotomes (3-4)are mounted longitudinally along the balloon surface

Atherotomes Balloon diameter3 2 & 3.25 mm 4 3.5 & 4 mm

Technique Less compliant and trackability

Tortuous proximal anatomy – CBA may not be feasible

Risk of blade fracture or retention – minimized by slowly inflation and deflation

Complications: Slightly higher risk of coronary perforation (0.8 %

vs 0.0 %)

Conclusion: Cutting/scoring balloon In RCT, cutting balloon alone has not shown to

improve outcomes compared to balloon angioplasty

CBA – Plaque modification in complex procedures

Bifurcation lesions Ostial lesions Mild to moderately calcified lesions Instent restenosis

Lesion selection Bifurcation lesion – plaque shift and high

restenosis CBA lower restenosis (40 % vs 67%)

Instent restenosis (REDUCE 3 trial ) Reduced balloon slippage Plaque extension through the stent struts

Ostial lesions

CBA recommendations Class IIb

Cutting balloon angioplasty might be considered to avoid slippage-induced coronary artery trauma during PCI for in-stent restenosis or ostial lesions in side branches. (LOE: C)

Class III:Cutting balloon angioplasty should not be performed routinely during PCI. (LOE: A)

2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention

Angiosculpt Scoring balloon catheter – semicompliant

balloon with nitinol spiral cage

Low crossing profile (2.7F)

More flexible alternative to cutting balloon

Laser angioplasty ELCA – precise plaque removal

Infrequently used (high cost, lack of benefit over PCI alone)

Adjunctive method for debulking

Excimer laserExcimer laser in UV wavelength is well absorbed by both atheromatous plaques and thrombi

Laser : Thrombolysis Inhibit platelet aggregation May ablate atherosclerotic plaque

Tissue ablation mechanisms: Vaporization of tissue (Photothermal effect) Ejection of debris (Photoacoustic effect) Direct breakdown of molecules (Photochemical

dissociation)

Excimer laser (ELCA) Photoacoustic effects and collateral damage

Technique: Laser catheter 1 cm smaller than reference

diameter of vessel Saline flush Slow catheter advancement at 0.2 mm/s → maximal

ablation

ECLA: Lesion selection Long lesions

Moderately calcified lesions

Total occlusions (AMRO trial – successful recanalization in 60 % of uncrossable total occlusions with conventional guidewires)

Undilatable lesions ( ECLA has similar success rate as PTRA)

No benefit in ISR

ECLA recommendations Class IIb . Laser angioplasty might be considered for

fibrotic or moderately calcified lesions that cannot be crossed or dilated with conventional balloon angioplasty.(LOE: C)

Class III. Laser angioplasty should not be used routinely during PCI. (LOE: A)

2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention

Directional coronary atherectomy (DCA) First FDA approved non balloon PCI device (1990)

SilverHawk – novel plaque excision system

DCA failed to acheive better clinical outcome compared to PTCA in randomized trials

Periprocedural MI Difficulty in achieving optimal debulking

Rotational atherectomy (PTRA)

Mechanism of PTRA Differential cutting

Cuts more rigid, inelastic material

Orthogonal friction displacement Reduces friction between vessel wall and entering device

Rota hardwares

Rota burr

Burr /artery ratio: 0.7 Rotational speed up to 2,00,000 rpm

Lower rpm 1,40,000 a/w less heat generation and platelet activation

Runs should be limited to 20 seconds

Decelerations of >5000 should be avoided

Contraindications to Rotablation Dissection Angulated lesions (> 60-90⁰) Thrombus containing lesion Saphenous venous grafts Acute MI

Indications for PTRA Calcified lesions Undilatable lesions Bifurcation lesion Ostial lesion

Complications Slow flow, no reflow Non QWMI Coronary perforation Dissection Bradycardia & AV

block Vasospasm

Rotablator system failure

Burr entrapment (Kokesi effect)

Burr detachment Burr stalling Rota guide wire

fracture

PTRA recommendations Class IIa

Rotational atherectomy is reasonable for fibrotic or heavily calcified lesions that might not be crossed by a balloon catheter or adequately dilated before stent implantation. (LOE: C)

Class III: Rotational atherectomy should not be performed routinely for de novo lesions or in-stent restenosis. (LOE: A)

Mechanical thrombectomy PCI in acute MI @ distal emboli, no reflow & abrupt

closure

Thrombectomy in primary PCI was a/w improved myocardial perfusion (TIMI III flow, MBG 3, & ST resolution)

No difference in overall 30 day mortality

Increased risk of stroke

Survival benefit with manual aspiration catheters and worse outcome with mechanical devices

Simple vs ‘Complex’

X-Sizer AngioJet ThromCat

Pronto Export Diver

Manual thrombus aspiration Reduction of thrombotic burden Prevents of thrombus embolization Preservation of microvascular integrity Reduction of infarct size Improved myocardial tissue perfusion Improved LV function recovery and modelling

Limitations: Difficult delivery along tortuous vessels Reduced ability to aspirate at distal segment Dissection/perforation Distal embolization Insufficient thrombus removal

Power sourced thrombectomy devices Angiojet rheolytic thrombectomy Excimer laser X-Sizer

Higher extraction yield in large thrombus burden

Angiojet rheolytic thrombectomy Venturi effect:

Saline jets inside the catheter that travel at high speed to create a negative pressure zone

More effective in removing thrombus <48 hrs duration

Native coronaries, SVG grafts and peripheral arteries

Angiojet treat large thrombus burden in STEMI and provide more effective myocardial perfusion

Transient bradycardia

Recommendations

Aspiration thrombectomy is reasonable for patients undergoing primary PCI. (Level of Evidence: B)

Coronary ultrasound thrombolysis (Acolysis) Acolysis probe deliver low frequency sound –

lyse /liquify the thrombus

Therapeutic ultrasound frequency - 19 to 50 kHz

Higher power & low frequencies →higher amplitude of probe motion (20-110 micro m) → tissue disruption, cavitation and heating

Acolysis system in SVG PCI in ACS (RCT) Lower success and higher 30 day MACE

Embolic protection devices PCI of SVG grafts and thrombus lesions → distal

microembolization & spasm → no reflow and periprocedural MI

EPD’s minimize ischemic injury and no-reflow by trapping fragmented plaque & thrombus

EPD devices Primary PCI Disappointing

No benefit of routine EPD use in primary PCI (RCT- EMERALD, PROMISE, DEDICATION,

PROXIS)

Lack of benefit of EPD in acute MI Delay in reperfusion Increased embolization during delivery Embolization in to side branches

Class I Embolic protection devices (EPDs) should be used during saphenous vein graft (SVG) PCI when technically feasible. (Level of Evidence: B)

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