‘smash it!’ mark mason interventional cardiologist harefield hospital royal brompton and...

‘SMASH IT!’

Mark Mason

Interventional Cardiologist

Harefield HospitalRoyal Brompton and Harefield NHS Trust

Background

• Coronary occlusion in AMI comprises a variable amount of thrombus

• Evidence suggests that the degree of thrombus burden has an influence on prognosis (JACC 2007;50:573-83)

• Simply balloon dilating and stenting seems counter-intuitive in this context

• Do mechanical devices offer any greater thombus clearance than simple aspiration devices, and do they confer any clinical benefit?

ThromCat

• ‘Smash and suck’ type device

• High pressure jets ‘smash’ and internal ‘Archimedes screw’ draws in the debris

• Doesn’t require large permanent console- pack contains all that’s needed (other than some saline)

ThromCat

• Safety study presented at EuroPCR 2007 demonstrating safety and efficacy

• No randomised controlled trials

• Relatively easy to use (I said relatively!)

• Good anecdotal results

X-Sizer

• ‘Suck and smash’ type device

• Helical cutter in tip generates a vacuum and then acts as an ‘Archimedes screw’ to break up the thrombus and draw it in

• Again, no large console- all required equipment contained in disposable pack

X-Sizer

• Randomised controlled data available-• X AMINE ST trial (JACC 2005;46(2):246-52):

– 201 pts with AMI randomised to X-Sizer vs. conventional PCI

– Significantly higher overall ST resolution and >50% ST resolution

– Significant reduction in distal embolisation

– No difference in TIMI score, myocardial blush, or 6 month event rates

Angiojet

• ‘Smash and suck’ type device

• Requires large permanent console with additional disposable catheters

AngioJet Catheter- Mechanism of Action

Saline jets travel backwards at half the speed of sound to create a low pressure zone.

Thrombus is drawn into the catheter where it is fragmented by the jets and evacuated from the body.

Angiojet• Data variable-

– AiMI trial (JACC 2006;48(2):244-52)• Angiojet vs. conventional PCI:

– Higher final infarct size– Lower TIMI 3 rate– Higher MACE– Higher 30-day mortality

In the Angiojet group!

• WHY?

– Patients enrolled post-angio and did not require angiographic evidence of thrombus!

• Clearly cannot support routine use in AMI patients

So what are we supposed to do?

• De Luca et al- meta-analysis of 21 studies involving ‘rheolytic thrombectomy’ devices, simple aspiration devices, and distal protection devices (Am Heart J 2007;153(3):343-53)

– Improved TIMI grade, better myocardial blush grade, reduced distal embolisation, no difference in mortality

• No evidence that use of these devices confers a survival benefit (?TAPAS)

Should we bother at all then?

• Mortality is obviously important, butit is also commonly measured because it is

an easy ‘hard’ endpoint to assess

• The long term impact of significant infarcts is clear to us as clinicians, but

few have the will, nor the resources, to assess the morbidity associated with such scenarios

Do we use them or not?

• All three devices appear to be safe

• Routine use in AMI/rescue cannot be justified

• IMHO, they remain a useful adjunct to conventional modalities in highly selected cases and may make a difference

• No evidence exists to guide the choice of device