CC5&6: Introduction to intervention and PCI Flashcards
What is HAC service an example of?
-Primary PCI for treatment of STEMI
In cath lab where do x rays come from?
-Bottom to top
What are features of patient monitoring?
-12 lead ECG
-Sats
-NIBP
-Transducer set up
What are the 2 forms of access in PCI?
Radial
-Post-procedure sealed with radial band
Femoral
-Closed with closure plug, stitch device, manual pressure
Radial vs Femoral access
Radial
-Smaller artery makes advancing catheter more difficult
-Easier to control bleeding
Femoral
-Requires bedrest
-Puncture above bifurcation can cause retroperitoneal bleeding
What are standard drugs in PCI?
Lidocaine - local anaesthetic
Verapamil - Prevents vasoconstriction/vasospasm
Heparin - Prevents thrombus
Nitrates - Vasodilation of coronary arteries
Features of simple PCI
-Lesion in main vessel
-Landing zones away from branching vessels
Key steps to simple PCI lesions
-Supportive guide catheter
-Good guide wire position
-Predilate lesion with balloon
-Stent lesion
-Optimise stent
-Confirm with final images successful PCI with no complications
Diagnostic vs Guide catheters
What is standard diagnostic catheter for Angiogram?
-Judkins catheter
-Good at obtaining images
-May be used for PCI but not supportive enough (use Amplatz and EBU instead)
What can invasive pressure indicate about catheter position and what would effect be?
-Catheter angled towards wall
-Too deeply engaged
-Engaged in area of lesion
-Effect is damping or ventricularisation
How do you know whether LAD or Circ?
-In LAO, LAD is on the left
-In RAO, LAD is on the right
What is the O ring?
-O ring opened to add and remove angioplasty kit
-O ring causes a false pressure drop due to loss of feedback to transducer
What are guide wires?
-Guide wire comes after guide catheter
-Act as a track for other PCI equipment to pass along (e.g. balloons, stent, imaging)
Features of guide wire
-3cm radiopaque tip
-helps guide when positioning wire
Aims to identify:
-if guide wire has moved too distal
-selecting a small side branch
-ectopy may indicate wire irritating myocardium
What balloon is used to pre-dilate lesion?
Semi-compliant balloons
-Inflated to low pressure
-Conforms to lumen size
-Indicates if lesion is compliant
-Inflated using indeflator - fluid mix of saline and contrast
What does inflating balloon cause?
-Temporarily occluding flow
-Causes chest pain and ST elevation
What is the structure of balloon catheters?
Monorail balloon catheter:
-Guide wire passes through balloon itself
-Exits catheter proximal to balloon
What’s the nominal pressure?
-Pressure at which balloon reaches its nominal diameter (diameter on label)
What’s the rated burst pressure?
-Pressure at which balloon will burst according to testing
What’s the mean burst pressure?
-Mathematical mean pressure at which a balloon bursts
What stents used to be used?
-Bare metal stents (BMS)
-However, high risk of restenosis
What stents are now used?
Drug-eluting stents
-Slow release drug coating to prevent cell proliferation
-Preventing fibrosis and thrombus formation which could cause in-stent restenosis
Where should stent be positioned?
-From normal vessel to normal vessel
What are non-compliant balloons used for?
-Used to optimise stent
-Ultra high strength to handle overinflation pressures to expand stents
What is done post PCI?
-Remove all equipment except guide catheter
-Images in two planes to confirm stent well deployed
-Confirm no complications
=>Stent well deployed
=>Good flow to distal vessel
=>No dissection
Reasons why PCI would not be simple?
-Difficult to pass PCI equipment across lesion
-Is the lesion significant?
-Need more info about pattern of disease
-Lesion does not dilate
-Bifurcation lesions
-Small vessel disease
-In stent restenosis (ISR)
What is guide extension?
-Used to provide extra support for equipment delivery in tortuous vessels
-However, increased chance of damped pressure trace
What does balloon not inflating indicate?
-Calcified/heavily fibrosed disease
What are cutting balloons?
-Have 3 or 4 atherotomes (microsurgical blades) bonded longitudinally
-Dilate to a lower pressure than NC balloons, reducing the extent of vessel wall injury
What is rotablation?
-Catheter used to shave and remove the luminal calcium or fibrosis in a coronary artery
What is shockwave balloon?
-Balloon which delivers electrical impulse using a sonic pressure wave to break down calcium
What are drug-eluting balloons?
-Balloon coated with drug with rapid uptake and prolonged retention
-30sec - 1min inflations to transfer drug to intima
-Commonly used for small vessels, side branches and ISR
-Inflated to low pressure to decrease chance of stenosis
-Longer inflation time means chest pain and ECG changes are common
Why are bifurcation lesions more complex?
-Treating one vessel’s atheroma/thrombus may narrow or occlude the other vessel
What are examples of advances in treating Chronic Total Occlusions (CTOs)?
-Advances in guidewire and microcatheter technology
-Antegrade and Retrograde techniques
When could restenosis occur and what makes it more likely?
-Gradual re-narrowing of stented segments occurs mostly between 3 and 12 months after stent placement
-Caused by exaggerated neointimal formation
-Increased risk in patients with high cholesterol, kidney disease, smoking and uncontrolled diabetes/hypertension
What 2 things must we be aware of during STEMI?
-Reperfusion can be a high risk time for reperfusion arrhythmias
-RCA - most common bradyarrhythmia
-LAD - most common tachyarrhythmia
-May be high thrombus burden
-Consider thrombus removal device (e.g. Export catheter)
-IV blood thinners (e.g. integrilin)
What are some possible risks of PCI?
-Dissection/perforation of vessel
-Allergic reaction to medication/contrast
-Irregular heart rhythm
-Infection
-Bleeding at catheter insertion site
-Kidney failure
-Acute closure of coronary artery
-Emergency coronary artery bypass graft (CABG) surgery
Why is LIMA good choice for bypass graft?
-Left internal Mammary is an artery
-LIMA only has to be sewn once
-LIMA doesn’t have valves
What is a good option to treat vein graft stenosis
-CTO of native vessel
-Stent in vein would likely restenose
