Chronic Total Occlusions

Question 1

What is the association of CTO revascularization with a BMS compared to stenting of nonocclusive lesions?

Answer 1

Higher rates of restenosis and reocclusion

In the TOSCA-1 study, the rates of restenosis and reocclusion at 6-month follow-up were 55% and 11%, respectively.

Question 2

Which group of patients derives the greatest relative improvement in ejection fraction (EF) following successful revascularization?

Answer 2

Patients with global LV dysfunction

Baseline LV dysfunction was an independent predictor of improvement in LV function.

Question 3

What was the relative reduction in in-stent restenosis at 6-month follow-up when using sirolimus-eluting stents (SES) compared to BMS?

Answer 3

81% relative reduction

In the only randomized trial comparing SES and BMS, the rates were 36% vs. 7% (p < 0.0001).

Question 4

True or False: Successful total occlusion revascularization is associated with an increased need for repeat revascularization.

Answer 4

False

Successful revascularization is associated with significant improvement in event-free survival from bypass surgery.

Question 5

What is the most common mode of failure in total occlusion revascularization?

Answer 5

Inability to pass a guidewire across the occluded segment

Inability to cross the lesion occurred in 63% of cases in a study of 397 patients.

Question 6

How does cardiac tamponade typically present following PCI?

Answer 6

Diagnosed on average of 4.4 hours post-procedure

Cardiac tamponade is associated with a high likelihood of in-hospital death and MI.

Question 7

What factor has been related to recovery of impaired LV function after CTO revascularization?

Answer 7

Fibroblast growth factor expression

This factor is related to both the duration of occlusion and collateral function.

Question 8

What is the success rate of crossing lesions using laser wire compared to conventional guidewires?

Answer 8

53% for laser wire vs. 47% for conventional wire

This was observed in a randomized trial comparing the two techniques.

Question 9

Fill in the blank: Guidewires with a tapering tip diameter of _______ may facilitate wire engagement in microchannels of CTOs.

Answer 9

0.009 to 0.011 in.

These guidewires may penetrate occluded segments more easily.

Question 10

Which angiographic appearance has been associated with an increased likelihood of procedural success?

Answer 10

Tapered occlusion

This is compared to a blunted appearance or presence of side branches at the occlusion site.

Question 11

What does the hybrid algorithm for CTO revascularization assess?

Answer 11

Lesion length, proximal CTO cap ambiguity, distal vessel suitability, presence of collaterals

This algorithm improves procedural success and reduces contrast and radiation use.

Question 12

What percentage of diagnostic coronary angiograms identify a CTO?

Answer 12

Approximately one-third

However, attempted percutaneous revascularization of a total occlusion accounts for less than 10% of all PCIs.

Question 13

According to the National Heart, Lung, and Blood Dynamic Registry, where are CTOs most prevalent?

Answer 13

Right coronary artery (RCA)

CTOs are least common in the left circumflex artery (LCx).

Question 14

What is a common cause of CTO development?

Answer 14

Thrombotic occlusion

Followed by thrombus organization and collagen deposition.

Question 15

True or False: The extent of angiographic collateral flow predicts improvement in regional wall motion following successful revascularization.

Answer 15

False

Angiographic collateral flow does not predict improvement in wall motion or occurrence of restenosis.

Question 16

What access method for CTO PCI has been associated with similar technical success compared to femoral access?

Answer 16

Radial artery access

This includes bilateral radial artery approaches.

Question 17

What histological characteristic is common in approximately half of CTOs?

Answer 17

<99% stenotic despite thrombolysis in MI-0 flow

Inflammation is prevalent in the intima of CTOs, regardless of lesion age.

Question 18

What percentage of patients with STEMI not treated with reperfusion therapy have an occluded infarct-related artery within 4 hours?

Answer 18

87%

This percentage decreases over time, with 65% within 12 to 24 hours.

Question 19

What is the long-term mortality trend between failed and successful total occlusion revascularization?

Answer 19

Increased long-term mortality in failed attempts

Studies show consistently higher mortality among patients undergoing failed revascularization.

Question 20

What was the target lesion failure rate over a median follow-up period of 5.1 years for patients undergoing CTO revascularization?

Answer 20

16.0%

This data is based on a survey of 406 patients with extensive stenting.

Question 21

What were the predictors of target lesion failure identified in multivariable analysis?

Answer 21

• Number of stents implanted
• Persistent luminal narrowing

These predictors were identified despite the lesion complexity.

Question 22

True or False: The presence of a CTO in a non-IRA is a weak predictor of 5-year mortality.

Answer 22

False

It is a strong and independent predictor, especially in high-risk patients.

Question 23

What hazard ratio indicates the risk of mortality due to the presence of a CTO during the first 30 days following STEMI?

Answer 23

3.6

This hazard ratio was noted after adjusting for other factors.

Question 24

In the retrospective analysis by Valenti et al., what was reported as a survival advantage?

Answer 24

Complete revascularization involving successful treatment of the CTO

This study involved 486 patients with MVD.

Question 25

What was associated with improved survival among patients undergoing attempted CTO revascularization according to Safley and colleagues?

Answer 25

Successful CTO recanalization of the LAD artery

This finding was specific to the LAD artery and not the LCx or RCA.

Question 26

What percentage of patients experienced in-hospital mortality among those with grade III coronary perforation?

Answer 26

14.8%

This statistic was derived from a study of 56 patients undergoing PCI.

Question 27

Fill in the blank: The TLR rate among patients at late-term clinical follow-up was _____

Answer 27

13%

This was part of the outcomes reported among 24,465 patients undergoing PCI.

Question 28

What device caused coronary perforation in 50% of the cases among patients undergoing PCI?

Answer 28

Intracoronary balloon

This data comes from a study that analyzed the causes of coronary perforation.

Question 29

What was the combined procedural and in-hospital MI rate among patients with grade III coronary perforation?

Answer 29

42.9%

This rate highlights the complications associated with coronary perforation.

Question 30

What is the MACE rate reported at late-term clinical follow-up for patients who experienced grade III coronary perforation?

Answer 30

55.4%

MACE refers to major adverse cardiovascular events.