CTO

Question 1

What is the principle indication for CTO PCI?

Answer 1

Improve angina and quality of life

Question 2

What is the TIMI score of CTO?

Answer 2

0 with a duration of at least 3 months

Question 3

CTO PCI can improve? (3)

Answer 3

Capacity to exercise
Increase anaerobic threshold
Alleviate depression

Question 4

What are the risks of CTO PCI? (6)

Answer 4

-Acute MI
-Perforation
-CABG emergency
-Death
-Restenosis
-Stent Thrombosis

Question 5

CTO should be considered in patients with what? (2)

Answer 5

Angina resistant to medical therapy or large areas of ischemia of the occluded vessel

Question 6

What should be used and is critical for the success and safety of CTO PCI? (2)

Answer 6

Dual Angiography unless collateral circulation is originating from the CTO vessel

Question 7

How do you do dual angiography for CTO that the collaterals are not originating from the CTO vessel? (3)

Answer 7

-Donor vessel is injected first
-Followed by injection of the CTO vessel 2 to 3 seconds later with lower magnification
-Avoid panning to result degradation of image quality

Question 8

What are the four main anatomy focuses of CTO angiography?

Answer 8

-Proximal cap morphology
-Occlusion length, course, and composition (eg calcium)
-Quality of distal vessel
-Collateral circulation

Question 9

What are some CTO strategies to find the proximal cap and its type? (4)

Answer 9

-Dual injection
-Selective contrast injection through a microcatheter
-intravscular ultrasound (IVUS)
-Real time CCTA

Question 10

If the location of the proximal cap remains unclear, what should be done? (3)

Answer 10

A retrograde approach
Move the cap dissection
Reentry techniques

Question 11

What can lead to overestimation of the lesion length due to under filling and poor opacification of the distal vessel?

Answer 11

Antegrade only injections

Question 12

What guide wire is preferred when the vessel course is unclear or highly tortuous due to low risk of perforation?

Answer 12

Knuckled J tipped wire

Question 13

How should determining the feasibility of retrograde approach with high quality dual angiography be done?

Answer 13

Obtained during breath hold and no panning

Question 14

Retrograde crossings can be attempted by going through?

Answer 14

Collaterals or Bypass grafts

Question 15

The size of the collaterals is often assessed using what classification? (4)

Answer 15

Werner:
CC0: No continuous connection
CC1: Threadlike connection
CC2: Side branch like connection

Question 16

What technique is used to cross invisible septal collaterals?

Answer 16

Surfing technique (advancement of the guide wire with simultaneous rotation

Question 17

Why should previous angiograms be reviewed for potential collateral pathways because of change before or during the procedure?

Answer 17

Shifting collaterals

Question 18

What helps selective contrast tip injections that can help collateral anatomy?

Answer 18

Microcatheter

Question 19

Why are aorotcoronary bypass grafts favorable retrograde conduits? (3)

Answer 19

Absence of side branches
Predictable course
Large caliber

Question 20

Why are septal collaterals preferred over epicardial collaterals?

Answer 20

Lower risk of perforation that can cause tamponade.

Question 21

What wire is typically safe and easier to navigate through septal collaterals?

Answer 21

Soft tip polymer jacketed guidewires

Question 22

What can be used to safely dilate septal collaterals to facilitate microcatheter or device crossings?

Answer 22

Small balloons

Question 23

What is the oldest and most commonly used score for CTOs?

Answer 23

J-CTO

Question 24

What does J-CTO score developed to estimate?

Answer 24

Likelihood to successfully cross antegrade guidewire within 30 minutes based on 5 criteria

Question 25

What are the 5 criteria for J-CTO

Answer 25

1: At least 1 bend of >45 degrees in CTO entry or body 2: Occlusion length > 20 mm 3: Calcification 4: blunt proximal stump 5: Previously failed attempt.

Question 26

What are some other CTO scores? (4)

Answer 26

PROGRESS RECHARGE CASTLECT-RECTOR CTO CT

Question 27

What is used to assess the risk of CTO PCI?

Answer 27

Progress CTO complications score

Question 28

What are the 3 variables in Progress CTO complications Score?

Answer 28

-Length >23 mm -Use of Retrograde approach -age > 65 years old

Question 29

Why do you want to use micro catheters routinely for CTO crossings? (3)

Answer 29

Supporting guide wire Facilitating guide wire exchanges Tip reshaping

Question 30

Micro catheters can help cross what and protect from what?

Answer 30

-Retrograde collateral channels -Wire induced trauma

Question 31

What are the four CTO crossing techniques?

Answer 31

-Antegrade wiring -Antegrade dissection and re entry -Retrograde wiring -Retrograde dissection and re entry

Question 32

What can help determine guide wire position during crossing attempts?

Answer 32

Contralateral injections Orthogonal Angiographic Projections

Question 33

When the guidewire enters the true distal lumen, what should be done next? (2)

Answer 33

-Microcatheter is advanced into the distal true lumen -CTO guide wire is exchanged for a workhorse guide wire to minimize risk of distal vessel injury

Question 34

Why should subintimal guide wires not be advanced to the distal cap?

Answer 34

To prevent hematoma formation that can cause luminal compression and hinder guide wire crossing

Question 35

How does the STAR technique work (Subintimal Tracking and Reentry)

Answer 35

Uses non targeted reentry into the distal lumen by pushing a knuckled wire distally through the occluded segment until it reenters the true lumen distally

Question 36

What does the STAR technique often assiociate with? (2)

Answer 36

High rates of in stent restenosis Reocclusion

Question 37

What is the STAR technique currently only used for?

Answer 37

Bailout without stent implantation for preparation of a repeat CTO attempt.

Question 38

What is the most commonly used retrograde crossing technique?

Answer 38

Reverse controlled antegrade and retrograd tracking (reverse CART)

Question 39

How does reverse CART work for retrograde approach?

Answer 39

The ballon is inflated over the antegrade guidewire Followed by retrograde guide wire advancement through the space from the ballooon

Question 40

When should you stop CTO PCI? (5)

Answer 40

-High radiation dose (>5 gray air kerma dose) -Complications -High contrast volume -Exhaustion of crossing options -Fatigue of patient or doctor

Question 41

What should CTO lesions be before stent implantation?

Answer 41

Fully expanded and pre dilated with balloons/artherectomy.

Question 42

What is the average risk of complications?

Answer 42

3%

Question 43

To facilitate risk of donor vessel thrombosis, the goal for ACT is? (2)

Answer 43

-300 for antegrade cases 350 for retrograde cases