CC8: PCI and Radi-wire FFR Flashcards
What things could make PCI complex?
-Calcified lesions
-Bifurcation lesions
-Unprotected left main coronary lesions
-Chronic total occlusions
-Ostial lesion
-Graft PCI
How can calcified lesions affect stent?
-Stent under-expansion
-Stent malapposition
What is rotablation?
-Rapidly rotating burr to modify calcium
-Increase lumen size
Downsides of rotablation
-Higher complication rate compared to shockwave
-Causes trauma to vessel
-Doesn’t collect calcium so could flow downstream
What drugs are given during rotablation and why?
Heparin
-Prevents thrombus
Nitrate
-Prevents spasm
Verapamil
-no-reflow
Shockwave balloon and its benefits
-Sonic waves aim to fracture the intra-plaque calcium
-Reduced vascular intimal injury
-Ease of use
What needs to be considered when lesion is at bifurcation?
-There is a risk of losing the side branch when atheroma/thrombus is displaced
-So 2 wires are used to allow access to side branch if needed
Techniques for treating bifurcation lesions
-Jailed wires
-Post stent optimisation technique (POT)
-Kissing balloons
How to stent left main?
-Wires down LAD and Circ
-Megatron stent used because it can be over-expanded
-Likely to have pressure drop (have metaraminol)
-Left main inflations short as possible
Megatron stent and uses
-Can expand from 3.5 to 6mm
Used for:
-Tapered vessels
-Bifurcations
-Proximal optimisation technique (POT)
Issues with ostial stenting
-Ostium may be missed
-If struts extend to aorta, makes re-engaging coronary very difficult
-Stent struts can be flared
CTO antegrade technique
-Negotiate proximal cap
-Advance length of occluded segment
-Wire exchanges over micro-catheter
-Dilate and modify (rota/shockwave)
-Stent
-IVUS
CTO retrograde technique
-Soft wire negotiated through donor artery and collaterals into distal target vessel
-At site of occlusion, soft wire exchanged over microcatheter for stiff wire
Why is it easier to cross the fibrous cap retrogradely?
-Proximal cap is likely fibro-calcific
-Proximal cap is likely to be at a side branch ostium
Risks of graft PCI?
-Mean age of patients is older
-Higher burden of other disease
-Higher risk of no-reflow
-Higher risk of perforations
What factors could make PCI complex?
Patient comorbidites
-HF
-Diabetes
-Unstable angina/NSTEMI
Complex CAD
-Multi-vessel disease
-Left main disease
-Long lesion
Haemodynamic compromise
-Low EF
-Low CO
Operator experience
-Individual skills
-Personal experience
Why do we use pressure wire?
-Used for moderate/intermediate lesions to help decide whether or not a stenosis is significant
-Comparing blood pressure before and after stenosis provides information about blood flow
How is guide catheter used in pressure wire?
-Positioned at ostium of vessel
-Pressure is measured invasively via closed fluid system to transducer
How is transducer used in pressure wire?
-Ensure transducer at patient’s heart level
-Ensure good aortic pressure trace before starting pressure wire study
How to prepare pressure wire?
-Flush wire in packaging with saline
-Ensure pressure sensor fully immersed in saline, requires 20-30ml flush
-Allow pressure sensor to stabilise in saline solution for 1 min on flat surface before zeroing wire
Describe the pressure wire
-Wire has 3cm radio-opaque tip before pressure wire sensor
-Sensor is 3cm from tip of wire
4 steps in pressure wire
Step 1: Zero transducer
Step 2: Connect wire
Step 3: Equalise pressure wire
Step 4: Advance wire beyond lesion
(pressure sensor at least 2-3cm distal to lesion)
How to introduce pressure wire
-Minimal shaping to tip of wire to prevent damage to pressure sensor
-Introducer needle helps advance and position
-But must be removed prior to any equalisation or measurements being made
How are coronary spasms prevented in pressure wire study?
-Nitrates given intra-coronary beforehand
-Ensures vessel is at maximum lumen diameter
